WorldWideScience

Sample records for hypoxia-inducible factor hif-1a

  1. Quercetin suppresses hypoxia-induced accumulation of hypoxia-inducible factor-1alpha (HIF-1alpha) through inhibiting protein synthesis.

    Science.gov (United States)

    Lee, Dae-Hee; Lee, Yong J

    2008-10-01

    Quercetin, a ubiquitous bioactive plant flavonoid, has been shown to inhibit the proliferation of cancer cells and induce the accumulation of hypoxia-inducible factor-1alpha (HIF-1alpha) in normoxia. In this study, under hypoxic conditions (1% O(2)), we examined the effect of quercetin on the intracellular level of HIF-1alpha and extracellular level of vascular endothelial growth factor (VEGF) in a variety of human cancer cell lines. Surprisingly, we observed that quercetin suppressed the HIF-1alpha accumulation during hypoxia in human prostate cancer LNCaP, colon cancer CX-1, and breast cancer SkBr3 cells. Quercetin treatment also significantly reduced hypoxia-induced secretion of VEGF. Suppression of HIF-1alpha accumulation during treatment with quercetin in hypoxia was not prevented by treatment with 26S proteasome inhibitor MG132 or PI3K inhibitor LY294002. Interestingly, hypoxia (1% O(2)) in the presence of 100 microM quercetin inhibited protein synthesis by 94% during incubation for 8 h. Significant quercetin concentration-dependent inhibition of protein synthesis and suppression of HIF-1alpha accumulation were observed under hypoxic conditions. Treatment with 100 microM cycloheximide, a protein synthesis inhibitor, replicated the effect of quercetin by inhibiting HIF-1alpha accumulation during hypoxia. These results suggest that suppression of HIF-1alpha accumulation during treatment with quercetin under hypoxic conditions is due to inhibition of protein synthesis. (c) 2008 Wiley-Liss, Inc.

  2. Unraveling the role of hypoxia-inducible factor (HIF)-1α and HIF-2α in the adaption process of human microvascular endothelial cells (HMEC-1) to hypoxia: Redundant HIF-dependent regulation of macrophage migration inhibitory factor.

    Science.gov (United States)

    Hahne, Martin; Schumann, Peggy; Mursell, Mathias; Strehl, Cindy; Hoff, Paula; Buttgereit, Frank; Gaber, Timo

    2018-03-01

    Hypoxia driven angiogenesis is a prominent feature of tissue regeneration, inflammation and tumor growth and is regulated by hypoxia-inducible factor (HIF)-1 and -2. The distinct functions of HIFs in the hypoxia-induced angiogenesis and metabolic switch of endothelial cells are still unknown and therefore aim of this study. We investigated the role of HIF-1 and -2 in the adaptation of immortalized human microvascular endothelial cells (HMEC-1) to hypoxic conditions (1% O 2 ) in terms of angiogenesis, cytokine secretion, gene expression and ATP/ADP-ratio using shRNA-mediated reduction of the oxygen sensitive α-subunits of either HIF-1 or HIF-2 or the combination of both. Reduction of HIF-1α diminished cellular energy, hypoxia-induced glycolytic gene expression, and angiogenesis not altering pro-angiogenic factors. Reduction of HIF-2α diminished hypoxia-induced pro-angiogenic factors, enhanced anti-angiogenic factors and attenuated angiogenesis not altering glycolytic gene expression. Reduction of both HIFs reduced cell survival, gene expression of glycolytic enzymes and pro-angiogenic factors as compared to the corresponding control. Finally, we identified the macrophage migration inhibitory factor (MIF) to be redundantly regulated by HIF-1 and HIF-2 and to be essential in the process of hypoxia-driven angiogenesis. Our results demonstrate a major impact of HIF-1 and HIF-2 on hypoxia-induced angiogenesis indicating distinct but also overlapping functions of HIF-1 and HIF-2. These findings open new possibilities for therapeutic approaches by specifically targeting the HIF-1 and HIF-2 or their target MIF. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Regulation of HIF prolyl hydroxylases by hypoxia-inducible factors.

    Science.gov (United States)

    Aprelikova, Olga; Chandramouli, Gadisetti V R; Wood, Matthew; Vasselli, James R; Riss, Joseph; Maranchie, Jodi K; Linehan, W Marston; Barrett, J Carl

    2004-06-01

    Hypoxia and induction of hypoxia-inducible factors (HIF-1alpha and HIF-2alpha) is a hallmark of many tumors. Under normal oxygen tension HIF-alpha subunits are rapidly degraded through prolyl hydroxylase dependent interaction with the von Hippel-Lindau (VHL) tumor suppressor protein, a component of E3 ubuiquitin ligase complex. Using microarray analysis of VHL mutated and re-introduced cells, we found that one of the prolyl hydroxylases (PHD3) is coordinately expressed with known HIF target genes, while the other two family members (PHD1 and 2) did not respond to VHL. We further tested the regulation of these genes by HIF-1 and HIF-2 and found that siRNA targeted degradation of HIF-1alpha and HIF-2alpha results in decreased hypoxia-induced PHD3 expression. Ectopic overexpression of HIF-2alpha in two different cell lines provided a much better induction of PHD3 gene than HIF-1alpha. In contrast, we demonstrate that PHD2 is not affected by overexpression or downregulation of HIF-2alpha. However, induction of PHD2 by hypoxia has HIF-1-independent and -dependent components. Short-term hypoxia (4 h) results in induction of PHD2 independent of HIF-1, while PHD2 accumulation by prolonged hypoxia (16 h) was decreased by siRNA-mediated degradation of HIF-1alpha subunit. These data further advance our understanding of the differential role of HIF factors and putative feedback loop in HIF regulation. Copyright 2004 Wiley-Liss, Inc.

  4. Characterization and functional analysis of hypoxia-inducible factor HIF1α and its inhibitor HIF1αn in tilapia.

    Science.gov (United States)

    Li, Hong Lian; Gu, Xiao Hui; Li, Bi Jun; Chen, Xiao; Lin, Hao Ran; Xia, Jun Hong

    2017-01-01

    Hypoxia is a major cause of fish morbidity and mortality in the aquatic environment. Hypoxia-inducible factors are very important modulators in the transcriptional response to hypoxic stress. In this study, we characterized and conducted functional analysis of hypoxia-inducible factor HIF1α and its inhibitor HIF1αn in Nile tilapia (Oreochromis niloticus). By cloning and Sanger sequencing, we obtained the full length cDNA sequences for HIF1α (2686bp) and HIF1αn (1308bp), respectively. The CDS of HIF1α includes 15 exons encoding 768 amino acid residues and the CDS of HIF1αn contains 8 exons encoding 354 amino acid residues. The complete CDS sequences of HIF1α and HIF1αn cloned from tilapia shared very high homology with known genes from other fishes. HIF1α show differentiated expression in different tissues (brain, heart, gill, spleen, liver) and at different hypoxia exposure times (6h, 12h, 24h). HIF1αn expression level under hypoxia is generally increased (6h, 12h, 24h) and shows extremely highly upregulation in brain tissue under hypoxia. A functional determination site analysis in the protein sequences between fish and land animals identified 21 amino acid sites in HIF1α and 2 sites in HIF1αn as significantly associated sites (α = 0.05). Phylogenetic tree-based positive selection analysis suggested 22 sites in HIF1α as positively selected sites with a p-value of at least 95% for fish lineages compared to the land animals. Our study could be important for clarifying the mechanism of fish adaptation to aquatic hypoxia environment.

  5. Menadione and ethacrynic acid inhibit the hypoxia-inducible factor (HIF) pathway by disrupting HIF-1α interaction with p300.

    Science.gov (United States)

    Na, Yu-Ran; Han, Ki-Cheol; Park, Hyunsung; Yang, Eun Gyeong

    2013-05-17

    Hypoxia is a general characteristic of most solid malignancies and intimately related to neoplastic diseases and cancer progression. Homeostatic response to hypoxia is primarily mediated by hypoxia inducible factor (HIF)-1α that elicits transcriptional activity through recruitment of the CREB binding protein (CBP)/p300 coactivator. Targeted blockade of HIF-1α binding to CBP/p300 would thus constitute a novel approach for cancer treatment by suppressing tumor angiogenesis and metastasis. Here, we identified inhibitors against the interaction between HIF-1α and p300 by a fluorescence polarization-based assay employing a fluorescently-labeled peptide containing the C-terminal activation domain of HIF-1α. Two small molecule inhibitors, menadione (MD) and ethacrynic acid (EA), were found to decrease expression of luciferase under the control of hypoxia-responsive elements in hypoxic cells as well as to efficiently block the interaction between the full-length HIF-1α and p300. While these compounds did not alter the expression level of HIF-1α, they down-regulated expression of a HIF-1α target vascular endothelial growth factor (VEGF) gene. Considering hypoxia-induced VEGF expression leading to highly aggressive tumor growth, MD and EA may provide new scaffolds for development of tumor therapeutic reagents as well as tools for a better understanding of HIF-1α-mediated hypoxic regulation. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Enhanceosomes as integrators of hypoxia inducible factor (HIF) and other transcription factors in the hypoxic transcriptional response.

    Science.gov (United States)

    Pawlus, Matthew R; Hu, Cheng-Jun

    2013-09-01

    Hypoxia is a prevalent attribute of the solid tumor microenvironment that promotes the expression of genes through posttranslational modifications and stabilization of alpha subunits (HIF1α and HIF2α) of hypoxia-inducible factors (HIFs). Despite significant similarities, HIF1 (HIF1α/ARNT) and HIF2 (HIF2α/ARNT) activate common as well as unique target genes and exhibit different functions in cancer biology. More surprisingly, accumulating data indicates that the HIF1- and/or HIF2-mediated hypoxia responses can be oncogenic as well as tumor suppressive. While the role of HIF in the hypoxia response is well established, recent data support the concept that HIF is necessary, but not sufficient for the hypoxic response. Other transcription factors that are activated by hypoxia are also required for the HIF-mediated hypoxia response. HIFs, other transcription factors, co-factors and RNA poll II recruited by HIF and other transcription factors form multifactorial enhanceosome complexes on the promoters of HIF target genes to activate hypoxia inducible genes. Importantly, HIF1 or HIF2 requires distinct partners in activating HIF1 or HIF2 target genes. Because HIF enhanceosome formation is required for the gene activation and distinct functions of HIF1 and HIF2 in tumor biology, disruption of the HIF1 or HIF2 specific enhanceosome complex may prove to be a beneficial strategy in tumor treatment in which tumor growth is specifically dependent upon HIF1 or HIF2 activity. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. TCDD Induces the Hypoxia-Inducible Factor (HIF-1α Regulatory Pathway in Human Trophoblastic JAR Cells

    Directory of Open Access Journals (Sweden)

    Tien-Ling Liao

    2014-09-01

    Full Text Available The exposure to dioxin can compromise pregnancy outcomes and increase the risk of preterm births. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD has been demonstrated to induce placental hypoxia at the end of pregnancy in a rat model, and hypoxia has been suggested to be the cause of abnormal trophoblast differentiation and placental insufficiency syndromes. In this study, we demonstrate that the non-hypoxic stimulation of human trophoblastic cells by TCDD strongly increased hypoxia inducible factor-1 alpha (HIF-1α stabilization. TCDD exposure induced the generation of reactive oxygen species (ROS and nitric oxide. TCDD-induced HIF-1α stabilization and Akt phosphorylation was inhibited by pretreatment with wortmannin (a phosphatidylinositol 3-kinase (PI3K inhibitor or N-acetylcysteine (a ROS scavenger. The augmented HIF-1α stabilization by TCDD occurred via the ROS-dependent activation of the PI3K/Akt pathway. Additionally, a significant increase in invasion and metallomatrix protease-9 activity was found in TCDD-treated cells. The gene expression of vascular endothelial growth factor and placental growth factor was induced upon TCDD stimulation, whereas the protein levels of peroxisome proliferator-activated receptor γ (PPARγ, PPARγ coactivator-1α, mitochondrial transcription factor, and uncoupling protein 2 were decreased. Our results indicate that an activated HIF-1α pathway, elicited oxidative stress, and induced metabolic stress contribute to TCDD-induced trophoblastic toxicity. These findings may provide molecular insight into the TCDD-induced impairment of trophoblast function and placental development.

  8. Hypoxia-inducible factor-1β (HIF-1β) is upregulated in a HIF-1α-dependent manner in 518A2 human melanoma cells under hypoxic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mandl, Markus, E-mail: mmandl@mail.austria.com; Kapeller, Barbara; Lieber, Roman; Macfelda, Karin

    2013-04-26

    Highlights: •HIF-1β is a hypoxia-responsive protein in 518A2 human melanoma cells. •HIF-1β is upregulated in a HIF-1α-dependent manner under hypoxic conditions. •HIF-1β is not elevated due to heterodimerization with HIF-1α per se. •HIF-1β inducibility has a biological relevance as judged in Het-CAM model. -- Abstract: Solid tumors include hypoxic areas due to excessive cell proliferation. Adaptation to low oxygen levels is mediated by the hypoxia-inducible factor (HIF) pathway promoting invasion, metastasis, metabolic alterations, chemo-resistance and angiogenesis. The transcription factor HIF-1, the major player within this pathway consists of HIF-1α and HIF-1β. The alpha subunit is continuously degraded under normoxia and becomes stabilized under reduced oxygen supply. In contrast, HIF-1β is generally regarded as constitutively expressed and being present in excess within the cell. However, there is evidence that the expression of this subunit is more complex. The aim of this study was to investigate the role of HIF-1β in human melanoma cells. Among a panel of five different cell lines, in 518A2 cells exposed to the hypoxia-mimetic cobalt chloride HIF-1β was rapidly elevated on protein level. Knockdown experiments performed under cobalt chloride-exposure and hypoxia revealed that this effect was mediated by HIF-1α. The non-canonical relationship between these subunits was further confirmed by pharmacologic inhibition of HIF-1α and by expression of a dominant-negative HIF mutant. Overexpression of HIF-1α showed a time delay in HIF-1β induction, thus arguing for HIF-1β de novo synthesis rather than protein stabilization by heterodimerization. A Hen’s egg test-chorioallantoic membrane model of angiogenesis and invasion indicated a local expression of HIF-1β and implies a biological relevance of these findings. In summary, this study demonstrates the HIF-1α-dependent regulation of HIF-1β under hypoxic conditions for the first time. The

  9. Hypoxia-inducible factor-1β (HIF-1β) is upregulated in a HIF-1α-dependent manner in 518A2 human melanoma cells under hypoxic conditions

    International Nuclear Information System (INIS)

    Mandl, Markus; Kapeller, Barbara; Lieber, Roman; Macfelda, Karin

    2013-01-01

    Highlights: •HIF-1β is a hypoxia-responsive protein in 518A2 human melanoma cells. •HIF-1β is upregulated in a HIF-1α-dependent manner under hypoxic conditions. •HIF-1β is not elevated due to heterodimerization with HIF-1α per se. •HIF-1β inducibility has a biological relevance as judged in Het-CAM model. -- Abstract: Solid tumors include hypoxic areas due to excessive cell proliferation. Adaptation to low oxygen levels is mediated by the hypoxia-inducible factor (HIF) pathway promoting invasion, metastasis, metabolic alterations, chemo-resistance and angiogenesis. The transcription factor HIF-1, the major player within this pathway consists of HIF-1α and HIF-1β. The alpha subunit is continuously degraded under normoxia and becomes stabilized under reduced oxygen supply. In contrast, HIF-1β is generally regarded as constitutively expressed and being present in excess within the cell. However, there is evidence that the expression of this subunit is more complex. The aim of this study was to investigate the role of HIF-1β in human melanoma cells. Among a panel of five different cell lines, in 518A2 cells exposed to the hypoxia-mimetic cobalt chloride HIF-1β was rapidly elevated on protein level. Knockdown experiments performed under cobalt chloride-exposure and hypoxia revealed that this effect was mediated by HIF-1α. The non-canonical relationship between these subunits was further confirmed by pharmacologic inhibition of HIF-1α and by expression of a dominant-negative HIF mutant. Overexpression of HIF-1α showed a time delay in HIF-1β induction, thus arguing for HIF-1β de novo synthesis rather than protein stabilization by heterodimerization. A Hen’s egg test-chorioallantoic membrane model of angiogenesis and invasion indicated a local expression of HIF-1β and implies a biological relevance of these findings. In summary, this study demonstrates the HIF-1α-dependent regulation of HIF-1β under hypoxic conditions for the first time. The

  10. Hypoxia-induced cytotoxic drug resistance in osteosarcoma is independent of HIF-1Alpha.

    Directory of Open Access Journals (Sweden)

    Jennifer Adamski

    Full Text Available Survival rates from childhood cancer have improved dramatically in the last 40 years, such that over 80% of children are now cured. However in certain subgroups, including metastatic osteosarcoma, survival has remained stubbornly poor, despite dose intensive multi-agent chemotherapy regimens, and new therapeutic approaches are needed. Hypoxia is common in adult solid tumours and is associated with treatment resistance and poorer outcome. Hypoxia induces chemotherapy resistance in paediatric tumours including neuroblastoma, rhabdomyosarcoma and Ewing's sarcoma, in vitro, and this drug resistance is dependent on the oxygen-regulated transcription factor hypoxia inducible factor-1 (HIF-1. In this study the effects of hypoxia on the response of the osteosarcoma cell lines 791T, HOS and U2OS to the clinically relevant cytotoxics cisplatin, doxorubicin and etoposide were evaluated. Significant hypoxia-induced resistance to all three agents was seen in all three cell lines and hypoxia significantly reduced drug-induced apoptosis. Hypoxia also attenuated drug-induced activation of p53 in the p53 wild-type U2OS osteosarcoma cells. Drug resistance was not induced by HIF-1α stabilisation in normoxia by cobalt chloride nor reversed by the suppression of HIF-1α in hypoxia by shRNAi, siRNA, dominant negative HIF or inhibition with the small molecule NSC-134754, strongly suggesting that hypoxia-induced drug resistance in osteosarcoma cells is independent of HIF-1α. Inhibition of the phosphoinositide 3-kinase (PI3K pathway using the inhibitor PI-103 did not reverse hypoxia-induced drug resistance, suggesting the hypoxic activation of Akt in osteosarcoma cells does not play a significant role in hypoxia-induced drug resistance. Targeting hypoxia is an exciting prospect to improve current anti-cancer therapy and combat drug resistance. Significant hypoxia-induced drug resistance in osteosarcoma cells highlights the potential importance of hypoxia as a target

  11. Hypoxia Inducible Factor-1α (HIF-1 α and its Role in Tumour Progression to Malignancy

    Directory of Open Access Journals (Sweden)

    Gaurav Mrinal Sharma

    2008-07-01

    Full Text Available Hypoxia is a condition in which an area of the body or a tissue is deprived of sufficient supply of oxygen. The lack of nutrients in a hypoxic tissue generally causes apoptosis but some cells are able to adapt to this hypoxic environment and resist apoptosis. This adaptation occurs as a result of gene activation. Hypoxia is a characteristic feature of many cancers and is the stimulus for overexpression of HIF-1α - a basic loop-helix PAS protein family subunit of HIF, which allows the cell to adapt and survive in hostile environment. The presence of hypoxia and HIF-1α is correlated with an increased risk of metastasis and techniques that can inhibit hypoxia inducible factor may be instrumental in finding a cure for cancer.

  12. Hypoxia-inducible factor-1β (HIF-1β) is upregulated in a HIF-1α-dependent manner in 518A2 human melanoma cells under hypoxic conditions.

    Science.gov (United States)

    Mandl, Markus; Kapeller, Barbara; Lieber, Roman; Macfelda, Karin

    2013-04-26

    Solid tumors include hypoxic areas due to excessive cell proliferation. Adaptation to low oxygen levels is mediated by the hypoxia-inducible factor (HIF) pathway promoting invasion, metastasis, metabolic alterations, chemo-resistance and angiogenesis. The transcription factor HIF-1, the major player within this pathway consists of HIF-1α and HIF-1β. The alpha subunit is continuously degraded under normoxia and becomes stabilized under reduced oxygen supply. In contrast, HIF-1β is generally regarded as constitutively expressed and being present in excess within the cell. However, there is evidence that the expression of this subunit is more complex. The aim of this study was to investigate the role of HIF-1β in human melanoma cells. Among a panel of five different cell lines, in 518A2 cells exposed to the hypoxia-mimetic cobalt chloride HIF-1β was rapidly elevated on protein level. Knockdown experiments performed under cobalt chloride-exposure and hypoxia revealed that this effect was mediated by HIF-1α. The non-canonical relationship between these subunits was further confirmed by pharmacologic inhibition of HIF-1α and by expression of a dominant-negative HIF mutant. Overexpression of HIF-1α showed a time delay in HIF-1β induction, thus arguing for HIF-1β de novo synthesis rather than protein stabilization by heterodimerization. A Hen's egg test-chorioallantoic membrane model of angiogenesis and invasion indicated a local expression of HIF-1β and implies a biological relevance of these findings. In summary, this study demonstrates the HIF-1α-dependent regulation of HIF-1β under hypoxic conditions for the first time. The results indicate a novel cell specific mechanism which might prevent HIF-1β to become a limiting factor. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Flavonoids-induced accumulation of hypoxia-inducible factor (HIF)-1alpha/2alpha is mediated through chelation of iron.

    Science.gov (United States)

    Park, Sung-Soo; Bae, Insoo; Lee, Yong J

    2008-04-15

    Hypoxia-inducible factor-1 alpha (HIF-1alpha) is the regulatory subunit of the heterodimeric transcription factor HIF-1 that is the key regulator of cellular response to low oxygen tension. Under normoxic conditions, HIF-1alpha is continuously degraded by the ubiquitin-proteasome pathway through pVHL (von Hippel-Lindau tumor suppressor protein). Under hypoxic conditions, HIF-1alpha is stabilized and induces the transcription of HIF-1 target genes. Quercetin, a flavonoid with anti-oxidant, anti-inflammatory, and kinase modulating properties, has been found to induce HIF-1alpha accumulation and VEGF secretion in normoxia. In this study, the molecular mechanisms of quercetin-mediated HIF-1alpha accumulation were investigated. Previous studies have shown that, in addition to being induced by hypoxia, HIF-1alpha can be induced through the phosphatidylinositol 3-kinase (PI3K)/Akt and p53 signaling pathways. But our study revealed, through p53 mutant-type as well as p53 null cell lines, that neither the PI3K/Akt nor the p53 signaling pathway is required for quercetin-induced HIF-1alpha accumulation. And we observed that HIF-1alpha accumulated by quercetin is not ubiquitinated and the interaction of HIF-1alpha with pVHL is reduced, compared with HIF-1alpha accumulated by the proteasome inhibitor MG132. The use of quercetin's analogues showed that only quercetin and galangin induce HIF-1/2alpha accumulation and this effect is completely reversed by additional iron ions. This is because quercetin and galangin are able to chelate cellular iron ions that are cofactors of HIF-1/2alpha proline hydroxylase (PHD). These data suggest that quercetin inhibits the ubiquitination of HIF-1/2alpha in normoxia by hindering PHD through chelating iron ions.

  14. Hif1a inactivation rescues photoreceptor degeneration induced by a chronic hypoxia-like stress.

    Science.gov (United States)

    Barben, Maya; Ail, Divya; Storti, Federica; Klee, Katrin; Schori, Christian; Samardzija, Marijana; Michalakis, Stylianos; Biel, Martin; Meneau, Isabelle; Blaser, Frank; Barthelmes, Daniel; Grimm, Christian

    2018-04-17

    Reduced choroidal blood flow and tissue changes in the ageing human eye impair oxygen delivery to photoreceptors and the retinal pigment epithelium. As a consequence, mild but chronic hypoxia may develop and disturb cell metabolism, function and ultimately survival, potentially contributing to retinal pathologies such as age-related macular degeneration (AMD). Here, we show that several hypoxia-inducible genes were expressed at higher levels in the aged human retina suggesting increased activity of hypoxia-inducible transcription factors (HIFs) during the physiological ageing process. To model chronically elevated HIF activity and investigate ensuing consequences for photoreceptors, we generated mice lacking von Hippel Lindau (VHL) protein in rods. This activated HIF transcription factors and led to a slowly progressing retinal degeneration in the ageing mouse retina. Importantly, this process depended mainly on HIF1 with only a minor contribution of HIF2. A gene therapy approach using AAV-mediated RNA interference through an anti-Hif1a shRNA significantly mitigated the degeneration suggesting a potential intervention strategy that may be applicable to human patients.

  15. HIF-1 and NDRG2 contribute to hypoxia-induced radioresistance of cervical cancer Hela cells

    International Nuclear Information System (INIS)

    Liu, Junye; Zhang, Jing; Wang, Xiaowu; Li, Yan; Chen, Yongbin; Li, Kangchu; Zhang, Jian; Yao, Libo; Guo, Guozhen

    2010-01-01

    Hypoxia inducible factor 1 (HIF-1), the key mediator of hypoxia signaling pathways, has been shown involved in hypoxia-induced radioresistance. However, the underlying mechanisms are unclear. The present study demonstrated that both hypoxia and hypoxia mimetic cobalt chloride could increase the radioresistance of human cervical cancer Hela cells. Meanwhile, ectopic expression of HIF-1 could enhance the resistance of Hela cells to radiation, whereas knocking-down of HIF-1 could increase the sensitivity of Hela cells to radiation in the presence of hypoxia. N-Myc downstream-regulated gene 2 (NDRG2), a new HIF-1 target gene identified in our lab, was found to be upregulated by hypoxia and radiation in a HIF-1-dependent manner. Overexpression of NDRG2 resulted in decreased sensitivity of Hela cells to radiation while silencing NDRG2 led to radiosensitization. Moreover, NDRG2 was proved to protect Hela cells from radiation-induced apoptosis and abolish radiation-induced upregulation of Bax. Taken together, these data suggest that both HIF-1 and NDRG2 contribute to hypoxia-induced tumor radioresistance and that NDRG2 acts downstream of HIF-1 to promote radioresistance through suppressing radiation-induced Bax expression. It would be meaningful to further explore the clinical application potential of HIF-1 and NDRG2 blockade as radiosensitizer for tumor therapy.

  16. Overexpression of Hypoxia-Inducible Factor-1α Exacerbates Endothelial Barrier Dysfunction Induced by Hypoxia

    Directory of Open Access Journals (Sweden)

    Pei Wang

    2013-09-01

    Full Text Available Background/Aims: The mechanisms involved in endothelial barrier dysfunction induced by hypoxia are incompletely understood. There is debate about the role of hypoxia-inducible factor-1α (HIF-1α in endothelial barrier disruption. The aim of this study was to investigate the effect of genetic overexpression of HIF-1α on barrier function and the underlying mechanisms in hypoxic endothelial cells. Methods: The plasmid pcDNA3.1/V5-His-HIF-1α was stably transfected into human endothelial cells. The cells were exposed to normoxia or hypoxia. The mRNA and protein expressions of HIF-1α were detected by RT-PCR and Western blot respectively. The barrier function was assessed by measuring the transendothelial electrical resistance (TER. The Western blot analysis was used to determine the protein expression of glucose transporter-1 (GLUT-1, zonular occludens-1 (ZO-1, occludin, and myosin light chain kinase (MLCK in endothelial cells. The mRNA expression of proinflammatory cytokines was detected by qRT-PCR. Results: Genetic overexpression of HIF-1α significantly increased the mRNA and protein expression of HIF-1α in endothelial cells. The overexpression of HIF-1α enhanced the hypoxia-induced increase of HIF-1α and GLUT-1 protein expression. HIF-1α overexpression not only exacerbated hypoxia-induced endothelial barrier dysfunction but also augmented hypoxia-induced up-regulation of MLCK protein expression. HIF-1α overexpression also enhanced IL-1β, IL-6 and TNF-α mRNA expression. Conclusion: We provide evidence that genetic overexpression of HIF-1α aggravates the hypoxia-induced endothelial barrier dysfunction via enhancing the up-regulation of MLCK protein expression caused by hypoxia, suggesting a potential role for HIF-1α in the pathogenesis of endothelial barrier dysfunction in hypoxia.

  17. HIF1 Contributes to Hypoxia-Induced Pancreatic Cancer Cells Invasion via Promoting QSOX1 Expression

    Directory of Open Access Journals (Sweden)

    Chen-Ye Shi

    2013-08-01

    Full Text Available Background: Quiescin sulfhydryl oxidase 1 (QSOX1, which oxidizes sulfhydryl groups to form disulfide bonds in proteins, is found to be over-expressed in various pancreatic cancer cell lines and patients. QSOX1 promotes invasion of pancreatic cancer cells by activating MMP-2 and MMP-9. However, its regulatory mechanism remains largely undefined. Methods: Real-time PCR and Western blot were employed to detect the expression of QSOX1 in human pancreatic cancer cell lines under hypoxic condition. Luciferase reporter and ChIP assays were used to assess the regulation of QSOX1 by hypoxia-inducible factor 1 (HIF-1. Small interfering RNA (siRNA was applied to knock down endogenous expression of QSOX1. Matrigel-coated invasion chamber essays were conducted to detect the invasion capacity of QSOX1-depleted cells. Results: Both hypoxia and hypoxia mimicking reagent up-regulated the expression of QSOX1 in human pancreatic cancer cell lines. Knockdown of HIF-1α eliminated hypoxia induced QSOX1 expression. HIF-1α was found directly bound to two hypoxia-response elements (HRE of QSOX1 gene, both of which were required for HIF-1 induced QSOX1 expression. Moreover, QSOX1 silencing blocked hypoxia-induced pancreatic cancer cells invasion. Conclusion: QSOX1 is a direct target of HIF-1 and may contribute to hypoxia-induced pancreatic cancer cells invasion.

  18. Dexamethasone impairs hypoxia-inducible factor-1 function

    International Nuclear Information System (INIS)

    Wagner, A.E.; Huck, G.; Stiehl, D.P.; Jelkmann, W.; Hellwig-Buergel, T.

    2008-01-01

    Hypoxia-inducible factor-1 (HIF-1) is a heterodimeric transcription-factor composed of α- and β-subunits. HIF-1 is not only necessary for the cellular adaptation to hypoxia, but it is also involved in inflammatory processes and wound healing. Glucocorticoids (GC) are therapeutically used to suppress inflammatory responses. Herein, we investigated whether GC modulate HIF-1 function using GC receptor (GR) possessing (HepG2) and GR deficient (Hep3B) human hepatoma cell cultures as model systems. Dexamethasone (DEX) treatment increased HIF-1α levels in the cytosol of HepG2 cells, while nuclear HIF-1α levels and HIF-1 DNA-binding was reduced. In addition, DEX dose-dependently lowered the hypoxia-induced luciferase activity in a reporter gene system. DEX suppressed the hypoxic stimulation of the expression of the HIF-1 target gene VEGF (vascular endothelial growth factor) in HepG2 cultures. DEX did not reduce hypoxically induced luciferase activity in HRB5 cells, a Hep3B derivative lacking GR. Transient expression of the GR in HRB5 cells restored the susceptibility to DEX. Our study discloses the inhibitory action of GC on HIF-1 dependent gene expression, which may be important with respect to the impaired wound healing in DEX-treated patients

  19. Induction of gastrin expression in gastrointestinal cells by hypoxia or cobalt is independent of hypoxia-inducible factor (HIF).

    Science.gov (United States)

    Xiao, Lin; Kovac, Suzana; Chang, Mike; Shulkes, Arthur; Baldwin, Graham S; Patel, Oneel

    2012-07-01

    Gastrin and its precursors have been shown to promote mitogenesis and angiogenesis in gastrointestinal tumors. Hypoxia stimulates tumor growth, but its effect on gastrin gene regulation has not been examined in detail. Here we have investigated the effect of hypoxia on the transcription of the gastrin gene in human gastric cancer (AGS) cells. Gastrin mRNA was measured by real-time PCR, gastrin peptides were measured by RIA, and gastrin promoter activity was measured by dual-luciferase reporter assay. Exposure to a low oxygen concentration (1%) increased gastrin mRNA concentrations in wild-type AGS cells (AGS) and in AGS cells overexpressing the gastrin receptor (AGS-cholecystokinin receptor 2) by 2.1 ± 0.4- and 4.1 ± 0.3-fold (P factor hypoxia-inducible factor 1 (HIF-1) or knockdown of either the HIF-1α or HIF-1β subunit did not affect gastrin promoter inducibility under hypoxia indicated that the hypoxic activation of the gastrin gene is likely HIF independent. Mutational analysis of previously identified Sp1 regulatory elements in the gastrin promoter also failed to abrogate the induction of promoter activity by hypoxia. The observations that hypoxia up-regulates the gastrin gene in AGS cells by HIF-independent mechanisms, and that this effect is enhanced by the presence of gastrin receptors, provide potential targets for gastrointestinal cancer therapy.

  20. Myeloid cell leukemia-1 (Mc1-1 is a candidate target gene of hypoxia-inducible factor-1 (HIF-1 in the testis

    Directory of Open Access Journals (Sweden)

    Palladino Michael A

    2012-12-01

    Full Text Available Abstract Background Spermatic cord torsion can lead to testis ischemia (I and subsequent ischemia-reperfusion (I/R causing germ cell-specific apoptosis. Previously, we demonstrated that the hypoxia-inducible factor-1 (HIF-1 transcription factor, a key regulator of physiological responses to hypoxia, is abundant in Leydig cells in normoxic and ischemic testes. We hypothesize that testicular HIF-1 activates the expression of antiapoptotic target genes to protect Leydig cells from apoptosis. In silico analysis of testis genes containing a consensus hypoxia response element (HRE, 5’-RCGTG-3’ identified myeloid cell leukemia-1 (Mcl-1 as a potential HIF-1 target gene. The purpose of this study was to determine whether HIF-1 shows DNA-binding activity in normoxic and ischemic testes and whether Mcl-1 is a target gene of testicular HIF-1. Methods The testicular HIF-1 DNA-binding capacity was analyzed in vitro using a quantitative enzyme-linked immunosorbent assay (ELISA and electrophoretic mobility shift assays (EMSA. MCL-1 protein expression was evaluated by immunoblot analysis and immunohistochemistry. The binding of testicular HIF-1 to the Mcl-1 gene was examined via chromatin immunoprecipitation (ChIP analysis. Results The ELISA and EMSA assays demonstrated that testicular HIF-1 from normoxic and ischemic testes binds DNA equally strongly, suggesting physiological roles for HIF-1 in the normoxic testis, unlike most tissues in which HIF-1 is degraded under normoxic conditions and is only activated by hypoxia. MCL-1 protein was determined to be abundant in both normoxic and ischemic testes and expressed in Leydig cells. In a pattern identical to that of HIF-1 expression, the steady-state levels of MCL-1 were not significantly affected by I or I/R and MCL-1 co-localized with HIF-1α in Leydig cells. Chromatin immunoprecipitation (ChIP analysis using a HIF-1 antibody revealed sequences enriched for the Mcl-1 promoter. Conclusions The results

  1. Hypoxia-inducible factor (HIF)-1α and CCN2 form a regulatory circuit in hypoxic nucleus pulposus cells: CCN2 suppresses HIF-1α level and transcriptional activity.

    Science.gov (United States)

    Tran, Cassie M; Fujita, Nobuyuki; Huang, Bau-Lin; Ong, Jessica R; Lyons, Karen M; Shapiro, Irving M; Risbud, Makarand V

    2013-05-03

    The objective of the study was to investigate if hypoxia-inducible factor (HIF)-1α and connective tissue growth factor (CCN2) form a regulatory network in hypoxic nucleus pulposus (NP) cells. A decrease in CCN2 expression and proximal promoter activity was observed in NP cells after hypoxic culture. Analysis of both human and mouse CCN2 promoters using the JASPAR core database revealed the presence of putative hypoxia response elements. Transfection experiments showed that both promoter activities and CCN2 expression decreases in hypoxia in a HIF-1α-dependent fashion. Interestingly, deletion analysis and mutation of the hypoxia responsive elements individually or in combination resulted in no change in promoter activity in response to hypoxia or in response to HIF-1α, suggesting an indirect mode of regulation. Notably, silencing of endogenous CCN2 increased HIF-1α levels and its target gene expression, suggesting a role for CCN2 in controlling basal HIF-1α levels. On the other hand, treatment of cells with rCCN2 resulted in a decrease in the ability of HIF-1α transactivating domain to recruit co-activators and diminished target gene expression. Last, knockdown of CCN2 in NP cells results in a significant decrease in GAG synthesis and expression of AGGRECAN and COLLAGEN II. Immunohistochemical staining of intervertebral discs of Ccn2 null embryos shows a decrease in aggrecan. These findings reveal a negative feedback loop between CCN2 and HIF-1α in NP cells and demonstrate a role for CCN2 in maintaining matrix homeostasis in this tissue.

  2. The tyrosine phosphatase SHP-1 regulates hypoxia inducible factor-1α (HIF-1α protein levels in endothelial cells under hypoxia.

    Directory of Open Access Journals (Sweden)

    Stefan K Alig

    Full Text Available The tyrosine phosphatase SHP-1 negatively influences endothelial function, such as VEGF signaling and reactive oxygen species (ROS formation, and has been shown to influence angiogenesis during tissue ischemia. In ischemic tissues, hypoxia induced angiogenesis is crucial for restoring oxygen supply. However, the exact mechanism how SHP-1 affects endothelial function during ischemia or hypoxia remains unclear. We performed in vitro endothelial cell culture experiments to characterize the role of SHP-1 during hypoxia.SHP-1 knock-down by specific antisense oligodesoxynucleotides (AS-Odn increased cell growth as well as VEGF synthesis and secretion during 24 hours of hypoxia compared to control AS-Odn. This was prevented by HIF-1α inhibition (echinomycin and apigenin. SHP-1 knock-down as well as overexpression of a catalytically inactive SHP-1 (SHP-1 CS further enhanced HIF-1α protein levels, whereas overexpression of a constitutively active SHP-1 (SHP-1 E74A resulted in decreased HIF-1α levels during hypoxia, compared to wildtype SHP-1. Proteasome inhibition (MG132 returned HIF-1α levels to control or wildtype levels respectively in these cells. SHP-1 silencing did not alter HIF-1α mRNA levels. Finally, under hypoxic conditions SHP-1 knock-down enhanced intracellular endothelial reactive oxygen species (ROS formation, as measured by oxidation of H2-DCF and DHE fluorescence.SHP-1 decreases half-life of HIF-1α under hypoxic conditions resulting in decreased cell growth due to diminished VEGF synthesis and secretion. The regulatory effect of SHP-1 on HIF-1α stability may be mediated by inhibition of endothelial ROS formation stabilizing HIF-1α protein. These findings highlight the importance of SHP-1 in hypoxic signaling and its potential as therapeutic target in ischemic diseases.

  3. Protein S-glutathionylation induced by hypoxia increases hypoxia-inducible factor-1α in human colon cancer cells.

    Science.gov (United States)

    Jeon, Daun; Park, Heon Joo; Kim, Hong Seok

    2018-01-01

    Hypoxia is a common characteristic of many types of solid tumors. Intratumoral hypoxia selects for tumor cells that survive in a low oxygen environment, undergo epithelial-mesenchymal transition, are more motile and invasive, and show gene expression changes driven by hypoxia-inducible factor-1α (HIF-1α) activation. Therefore, targeting HIF-1α is an attractive strategy for disrupting multiple pathways crucial for tumor growth. In the present study, we demonstrated that hypoxia increases the S-glutathionylation of HIF-1α and its protein levels in colon cancer cells. This effect is significantly prevented by decreasing oxidized glutathione as well as glutathione depletion, indicating that S-glutathionylation and the formation of protein-glutathione mixed disulfides is related to HIF-1α protein levels. Moreover, colon cancer cells expressing glutaredoxin 1 are resistant to inducing HIF-1α and expressing hypoxia-responsive genes under hypoxic conditions. Therefore, S-glutathionylation of HIF-1α induced by tumor hypoxia may be a novel therapeutic target for the development of new drugs. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Hypoxia-inducible factor-1α induces multidrug resistance protein in colon cancer

    Directory of Open Access Journals (Sweden)

    Lv Y

    2015-07-01

    Full Text Available Yingqian Lv, Shan Zhao, Jinzhu Han, Likang Zheng, Zixin Yang, Li Zhao Department of Oncology, The Second Hospital, Hebei Medical University, Shijiazhuang, Hebei Province, People’s Republic of China Abstract: Multidrug resistance is the major cause of chemotherapy failure in many solid tumors, including colon cancer. Hypoxic environment is a feature for all solid tumors and is important for the development of tumor resistance to chemotherapy. Hypoxia-inducible factor (HIF-1α is the key transcription factor that mediates cellular response to hypoxia. HIF-1α has been shown to play an important role in tumor resistance; however, the mechanism is still not fully understood. Here, we found that HIF-1α and the drug resistance-associated gene multidrug resistance associated protein 1 (MRP1 were induced by treatment of colon cancer cells with the hypoxia-mimetic agent cobalt chloride. Inhibition of HIF-1α by RNA interference and dominant-negative protein can significantly reduce the induction of MRP1 by hypoxia. Bioinformatics analysis showed that a hypoxia response element is located at -378 to -373 bp upstream of the transcription start site of MRP1 gene. Luciferase reporter assay combined with mutation analysis confirmed that this element is essential for hypoxia-mediated activation of MRP gene. Furthermore, RNA interference revealed that HIF-1α is necessary for this hypoxia-driven activation of MRP1 promoter. Importantly, chromatin immunoprecipitation analysis demonstrated that HIF-1α could directly bind to this HRE site in vivo. Together, these data suggest that MRP1 is a downstream target gene of HIF-1α, which provides a potential novel mechanism for HIF-1α-mediated drug resistance in colon cancer and maybe other solid tumors as well. Keywords: hypoxia, hypoxia-inducible factor-1α, multidrug resistance associated protein, transcriptional regulation, chemotherapy tolerance

  5. Altered expression of hypoxia-inducible factor-1α (HIF-1α and its regulatory genes in gastric cancer tissues.

    Directory of Open Access Journals (Sweden)

    Jihan Wang

    Full Text Available Tissue hypoxia induces reprogramming of cell metabolism and may result in normal cell transformation and cancer progression. Hypoxia-inducible factor 1-alpha (HIF-1α, the key transcription factor, plays an important role in gastric cancer development and progression. This study aimed to investigate the underlying regulatory signaling pathway in gastric cancer using gastric cancer tissue specimens. The integration of gene expression profile and transcriptional regulatory element database (TRED was pursued to identify HIF-1α ↔ NFκB1 → BRCA1 → STAT3 ← STAT1 gene pathways and their regulated genes. The data showed that there were 82 differentially expressed genes that could be regulated by these five transcription factors in gastric cancer tissues and these genes formed 95 regulation modes, among which seven genes (MMP1, TIMP1, TLR2, FCGR3A, IRF1, FAS, and TFF3 were hub molecules that are regulated at least by two of these five transcription factors simultaneously and were associated with hypoxia, inflammation, and immune disorder. Real-Time PCR and western blot showed increasing of HIF-1α in mRNA and protein levels as well as TIMP1, TFF3 in mRNA levels in gastric cancer tissues. The data are the first study to demonstrate HIF-1α-regulated transcription factors and their corresponding network genes in gastric cancer. Further study with a larger sample size and more functional experiments is needed to confirm these data and then translate into clinical biomarker discovery and treatment strategy for gastric cancer.

  6. Hypoxia induces epithelial-mesenchymal transition via activation of SNAI1 by hypoxia-inducible factor -1α in hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Zhang, Lin; Feng, Xiaobin; Dong, Jiahong; Qian, Cheng; Huang, Gang; Li, Xiaowu; Zhang, Yujun; Jiang, Yan; Shen, Junjie; Liu, Jia; Wang, Qingliang; Zhu, Jin

    2013-01-01

    High invasion and metastasis are the primary factors causing poor prognosis of patients with hepatocellular carcinoma (HCC). However, the molecular mechanisms underlying these biological behaviors have not been completely elucidated. In this study, we investigate the molecular mechanism by which hypoxia promotes HCC invasion and metastasis through inducing epithelial-mesenchymal transition (EMT). The expression of EMT markers was analyzed by immunohistochemistry. Effect of hypoxia on induction of EMT and ability of cell migration and invasion were performed. Luciferase reporter system was used for evaluation of Snail regulation by hypoxia-inducible factor -1α (HIF-1α). We found that overexpression of HIF-1α was observed in HCC liver tissues and was related to poor prognosis of HCC patients. HIF-1α expression profile was correlated with the expression levels of SNAI1, E-cadherin, N-cadherin and Vimentin. Hypoxia was able to induce EMT and enhance ability of invasion and migration in HCC cells. The same phenomena were also observed in CoCl2-treated cells. The shRNA-mediated HIF-1α suppression abrogated CoCl2-induced EMT and reduced ability of migration and invasion in HCC cells. Luciferase assay showed that HIF-1α transcriptional regulated the expression of SNAI1 based on two hypoxia response elements (HREs) in SNAI1 promoter. We demonstrated that hypoxia-stabilized HIF1α promoted EMT through increasing SNAI1 transcription in HCC cells. This data provided a potential therapeutic target for HCC treatment

  7. Effects of 12 metal ions on iron regulatory protein 1 (IRP-1) and hypoxia-inducible factor-1 alpha (HIF-1α) and HIF-regulated genes

    International Nuclear Information System (INIS)

    Li Qin; Chen Haobin; Huang Xi; Costa, Max

    2006-01-01

    Several metal ions that are carcinogenic affect cellular iron homeostasis by competing with iron transporters or iron-regulated enzymes. Some metal ions can mimic a hypoxia response in cells under normal oxygen tension, and induce expression of HIF-1α-regulated genes. This study investigated whether 12 metal ions altered iron homeostasis in human lung carcinoma A549 cells as measured by an activation of IRP-1 and ferritin level. We also studied hypoxia signaling by measuring HIF-1α protein levels, hypoxia response element (HRE)-driven luciferase reporter activity, and Cap43 protein level (an HIF-1α responsive gene). Our results show the following: (i) Ni(II), Co(II), V(V), Mn(II), and to a lesser extent As(III) and Cu(II) activated the binding of IRP-1 to IRE after 24 h, while the other metal ions had no effect; (ii) 10 of 12 metal ions induced HIF-1α protein but to strikingly different degrees. Two of these metal ions, Al(III) and Cd(II), did not induce HIF-1α protein; however, as indicated below, only Ni(II), Co (II), and to lesser extent Mn(II) and V(V) activated HIF-1α-dependent transcription. The combined effects of both [Ni(II) + As(III)] and [Ni(II) + Cr(VI)] on HIF-1α protein were synergistic; (iii) Addition of Fe(II) with Ni(II), Co(II), and Cr(VI) attenuated the induction of HIF-1α after 4 h treatment; (iv) Ni(II), Co(II), and Mn(II) significantly decrease ferritin level after 24 h exposure; (v) Ni(II), Co(II), V(V), and Mn(II) activated HRE reporter gene after 20 h treatment; (vi) Ni(II), Co(II), V(V), and Mn(II) increased the HIF-1-dependent Cap43 protein level after 24 h treatment. In conclusion, only Ni (II), Co (II), and to a lesser extent Mn(II) and V(V) significantly stabilized HIF-1α protein, activated IRP, decreased the levels of ferritin, induced the transcription of HIF-dependent reporter, and increased the expression of Cap43 protein levels (HIF-dependent gene). The mechanism for the significant stabilization and elevation of HIF-1

  8. Hypoxia-inducible factor-2α (HIF-2α), but not HIF-1α, is essential for hypoxic induction of class III β-tubulin expression in human glioblastoma cells.

    Science.gov (United States)

    Bordji, Karim; Grandval, Alexandra; Cuhna-Alves, Leilane; Lechapt-Zalcman, Emmanuèle; Bernaudin, Myriam

    2014-12-01

    Glioblastoma multiforme (GBM) is the deadliest form of primary brain cancer. Several reports have indicated aberrant levels of βIII-tubulin (βIII-t) in human GBM. βIII-t overexpression was linked to increasing malignancy in glial tumors and described to determine the onset of resistance to chemotherapy. Furthermore, a linkage was suggested between the induction of βIII-t expression and hypoxia, a hallmark of GBM. We investigated the role of hypoxia-inducible factor (HIF)-1α and HIF-2α in the regulation of the βIII-t gene (TUBB3) in GBM cells cultured in either normoxia or hypoxia. We report for the first time that HIF-2α, but not HIF-1α, is involved in hypoxia-induced βIII-t expression in GBM cells. By gene-reporter experiments and site-directed mutagenesis, we found that two overlapping hypoxia response elements located in the 3' UTR of the gene were involved in the activation of TUBB3. This occurred through an enhanced binding of HIF-2α to the 3' region, as revealed by an electrophoretic mobility shift assay. Conversely, the promoter of TUBB3 was shown to be inactive. In addition, we observed that HIF-1α exhibits a repressive effect on βIII-t expression in cells cultured in normoxia. These results show that both HIF-α isoforms have opposing effects on βIII-t expression in GBM cells. Finally, we observed that hypoxia-induced βIII-t expression is well correlated with the kinetics of HIF-2α protein stabilization. The evidence for a direct linkage between HIF-2α and increased expression of βIII-t by hypoxia suggests that an anti-HIF-2α strategy (i.e. by downregulating βIII-t) could be of potential interest for improving the treatment of GBM. © 2014 FEBS.

  9. The histone demethylases JMJD1A and JMJD2B are transcriptional targets of hypoxia-inducible factor HIF

    DEFF Research Database (Denmark)

    Beyer, Sophie; Kristensen, Malene Maag; Jensen, Kim Steen

    2008-01-01

    of these modifications is exerted by histone methyltransferases and the recently discovered histone demethylases. Here we show that the hypoxia-inducible factor HIF-1a binds to specific recognition sites in the genes encoding the jumonji family histone demethylases JMJD1A and JMJD2B and induces their expression....... Accordingly, hypoxic cells express elevated levels of JMJD1A and JMJD2B mRNA and protein. Furthermore, we find increased expression of JMJD1A and JMJD2B in renal cancer cells that have lost the von Hippel Lindau tumor suppressor protein VHL and therefore display a deregulated expression of HIF. Studies...... on ectopically expressed JMJD1A and JMJD2B indicate that both proteins retain their histone lysine demethylase activity in hypoxia and thereby might impact the hypoxic gene expression program....

  10. Hypoxia-inducible transcription factor-1α promotes hypoxia-induced A549 apoptosis via a mechanism that involves the glycolysis pathway

    International Nuclear Information System (INIS)

    Luo, FengMing; Liu, XiaoJing; Yan, NaiHong; Li, ShuangQing; Cao, GuiQun; Cheng, QingYing; Xia, QingJie; Wang, HongJing

    2006-01-01

    Hypoxia-inducible transcription factor-1α (HIF-1α), which plays an important role in controlling the hypoxia-induced glycolysis pathway, is a 'master' gene in the tissue hypoxia response during tumor development. However, its role in the apoptosis of non-small cell lung cancer remains unknown. Here, we have studied the effects of HIF-1α on apoptosis by modulating HIF-1α gene expression in A549 cells through both siRNA knock-down and over-expression. A549 cells were transfected with a HIF-1α siRNA plasmid or a HIF-1α expression vector. Transfected cells were exposed to a normoxic or hypoxic environment in the presence or absence of 25 mM HEPES and 2-deoxyglucose (2-DG) (5 mM). The expression of three key genes of the glycolysis pathway, glucose transporter type 1(GLUT1), phosphoglycerate kinase 1(PGK1), and hexokinase 1(HK1), were measured using real-time RT-PCR. Glycolysis was monitored by measuring changes of pH and lactate concentration in the culture medium. Apoptosis was detected by TUNEL assay and flow cytometry. Knocking down expression of HIF-1α inhibited the glycolysis pathway, increased the pH of the culture medium, and protected the cells from hypoxia-induced apoptosis. In contrast, over-expression of HIF-1α accelerated glycolysis in A549 cells, decreased the pH of the culture medium, and enhanced hypoxia-induced apoptosis. These effects of HIF-1α on glycolysis, pH of the medium, and apoptosis were reversed by treatment with the glycolytic inhibitor, 2-DG. Apoptosis induced by HIF-1α over-expression was partially inhibited by increasing the buffering capacity of the culture medium by adding HEPES. During hypoxia in A549 cells, HIF-1α promotes activity of the glycolysis pathway and decreases the pH of the culture medium, resulting in increased cellular apoptosis

  11. Suppression of the expression of hypoxia-inducible factor-1α by RNA interference alleviates hypoxia-induced pulmonary hypertension in adult rats.

    Science.gov (United States)

    Li, Ying; Shi, Bo; Huang, Liping; Wang, Xin; Yu, Xiaona; Guo, Baosheng; Ren, Weidong

    2016-12-01

    Hypoxia-inducible factor-1α (HIF-1α) has been implicated in the pathogenesis of hypoxic pulmonary hypertension (PH). However, the potential clinical value of HIF-1α as a therapeutic target in the treatment of PH has not yet been evaluated. In this study, an animal model of hypoxia-induced PH was established by exposing adult rats to 10% O2 for 3 weeks, and the effects of the lentivirus-mediated delivery of HIF-1α short hairpin RNA (shRNA) by intratracheal instillation prior to exposure to hypoxia on the manifestations of hypoxia-induced PH were assessed. The successful delivery of HIF-1α shRNA into the pulmonary arteries effectively suppressed the hypoxia-induced upregulation of HIF-1α, accompanied by the prominent attenuation the symptoms associated with hypoxia-induced PH, including the elevation of pulmonary arterial pressure, hypertrophy and hyperplasia of pulmonary artery smooth muscle cells (PASMCs), as well as the muscularization of pulmonary arterioles. In addition, the knockdown of HIF-1α in cultured rat primary PASMCs significantly inhibited the hypoxia-induced acceleration of the cell cycle and the proliferation of the PASMCs, suggesting that HIF-1α may be a direct mediator of PASMC hyperplasia in hypoxia-induced PH. In conclusion, this study demonstrates the potent suppressive effects of HIF-1α shRNA on hypoxia-induced PH and PASMC hyperplasia, providing evidence for the potential application of HIF-1α shRNA in the treatment of hypoxic PH.

  12. KNK437, abrogates hypoxia-induced radioresistance by dual targeting of the AKT and HIF-1α survival pathways

    International Nuclear Information System (INIS)

    Oommen, Deepu; Prise, Kevin M.

    2012-01-01

    Highlights: ► KNK437, a benzylidene lactam compound, is a novel radiosensitizer. ► KNK437 inhibits AKT signaling and abrogates the accumulation of HIF-1α under hypoxia. ► KNK437 abrogates hypoxia induced resistance to radiation. -- Abstract: KNK437 is a benzylidene lactam compound known to inhibit stress-induced synthesis of heat shock proteins (HSPs). HSPs promote radioresistance and play a major role in stabilizing hypoxia inducible factor-1α (HIF-1α). HIF-1α is widely responsible for tumor resistance to radiation under hypoxic conditions. We hypothesized that KNK437 sensitizes cancer cells to radiation and overrides hypoxia-induced radioresistance via destabilizing HIF-1α. Treatment of human cancer cells MDA-MB-231 and T98G with KNK437 sensitized them to ionizing radiation (IR). Surprisingly, IR did not induce HSPs in these cell lines. As hypothesized, KNK437 abrogated the accumulation of HIF-1α in hypoxic cells. However, there was no induction of HSPs under hypoxic conditions. Moreover, the proteosome inhibitor MG132 did not restore HIF-1α levels in KNK437-treated cells. This suggested that the absence of HIF-1α in hypoxic cells was not due to the enhanced protein degradation. HIF-1α is mainly regulated at the level of post-transcription and AKT is known to modulate the translation of HIF-1α mRNA. Interestingly, pre-treatment of cells with KNK437 inhibited AKT signaling. Furthermore, down regulation of AKT by siRNA abrogated HIF-1α levels under hypoxia. Interestingly, KNK437 reduced cell survival in hypoxic conditions and inhibited hypoxia-induced resistance to radiation. Taken together, these data suggest that KNK437 is an effective radiosensitizer that targets multiple pro-survival stress response pathways.

  13. A RNA antagonist of hypoxia-inducible factor-1alpha, EZN-2968, inhibits tumor cell growth

    DEFF Research Database (Denmark)

    Greenberger, Lee M; Horak, Ivan D; Filpula, David

    2008-01-01

    Hypoxia-inducible factor-1 (HIF-1) is a transcription factor that plays a critical role in angiogenesis, survival, metastasis, drug resistance, and glucose metabolism. Elevated expression of the alpha-subunit of HIF-1 (HIF-1alpha), which occurs in response to hypoxia or activation of growth facto...

  14. Zinc promotes the death of hypoxic astrocytes by upregulating hypoxia-induced hypoxia-inducible factor-1alpha expression via poly(ADP-ribose) polymerase-1.

    Science.gov (United States)

    Pan, Rong; Chen, Chen; Liu, Wen-Lan; Liu, Ke-Jian

    2013-07-01

    Pathological release of excess zinc ions has been implicated in ischemic brain cell death. However, the underlying mechanisms remain to be elucidated. In stroke, ischemia-induced zinc release and hypoxia-inducible factor-1 (HIF-1) accumulation concurrently occur in the ischemic tissue. The present study tests the hypothesis that the presence of high intracellular zinc concentration is a major cause of modifications to PARP-1 and HIF-1α during hypoxia, which significantly contributes to cell death during ischemia. Primary cortical astrocytes and C8-D1A cells were exposed to different concentrations of zinc chloride. Cell death rate and protein expression of HIF-1 and Poly(ADP-ribose) polymerase (PARP)-1 were examined after 3-h hypoxic treatment. Although 3-h hypoxia or 100 μM of zinc alone did not induce noticeable cytotoxicity, their combination led to a dramatic increase in astrocytic cell death in a zinc-concentration-dependent manner. Exposure of astrocytes to hypoxia for 3 h remarkably increased the levels of intracellular zinc and HIF-1α protein, which was further augmented by added exogenous zinc. Notably, HIF-1α knockdown blocked zinc-induced astrocyte death. Moreover, knockdown of PARP-1, another important protein in the response of hypoxia, attenuated the overexpression of HIF-1α and reduced the cell death rate. Our studies show that zinc promotes hypoxic cell death through overexpression of the hypoxia response factor HIF-1α via the cell fate determine factor PARP-1 modification, which provides a novel mechanism for zinc-mediated ischemic brain injury. © 2013 John Wiley & Sons Ltd.

  15. Changes in Hypoxia-Inducible Factor-1 (HIF-1) and Regulatory Prolyl Hydroxylase (PHD) Enzymes Following Hypoxic-Ischemic Injury in the Neonatal Rat.

    Science.gov (United States)

    Chu, Hannah X; Jones, Nicole M

    2016-03-01

    Hypoxia leads to activation of many cellular adaptive processes which are regulated by the transcription factor hypoxia-inducible factor-1 (HIF-1). HIF-1 consists of HIF-1α and HIF-1ß subunits and levels of HIF-1α protein are regulated by HIF prolyl-hydroxylase enzymes (PHD1, 2, 3). The aim of the current study was to investigate the expression of HIF-1α and PHDs at various time points after hypoxia-ischemia (HI), using a neonatal rat model of HI brain injury. Sprague-Dawley rat pups (postnatal day 7) were anaesthetized and underwent right carotid artery occlusion and were then exposed to 6 % oxygen for 2.5 h at 37 °C. HI injured animals demonstrated a significant reduction in the size of the ipsilateral hemisphere, compared to sham controls. Protein analysis using western blotting and enzyme-linked immunosorbent assay showed that 24 h after HI, there was a significant increase in PHD3 protein and an increase of HIF-1α compared to controls. At the 72 h time point, there was a reduction in PHD3 protein, which appeared to relate to cellular loss. There were no changes in PHD1 or PHD2 protein levels after HI when compared to age-matched controls. Further studies are necessary to establish roles for the HIF-1 regulatory enzyme PHD3 in brain injury processes.

  16. Hypoxia-inducible factor-1 alpha has a key role in hypoxic preconditioning.

    Science.gov (United States)

    Taie, Satoshi; Ono, Junichiro; Iwanaga, Yasuyuki; Tomita, Shuhei; Asaga, Takehiko; Chujo, Kosuke; Ueki, Masaaki

    2009-08-01

    Sublethal hypoxia induces tolerance to subsequent hypoxic insults in a process known as hypoxic preconditioning (HP). Hypoxia-inducible factor-1 alpha (HIF-1 alpha) is a key transcription protein involved in the mechanism of HP. In this study, we investigated the effects of HP on tissue oxygenation and expression of HIF-1 alpha gene targets in the brain using neural cell-specific HIF-1 alpha-deficient mice. The animals were exposed to 8% oxygen for 3 hours. Twenty-four hours later, the oxygen partial pressure (pO(2)) of brain tissue and gene expression were measured during hypoxia. HP improved the pO(2) of brain tissue during subsequent hypoxia with upregulated inducible nitric oxide synthase in wild-type mice, whereas HP had no detectable effect in the mutant mice. Our results indicate that the protective effects of HP may be partially mediated by improving tissue oxygenation via HIF-1 alpha and inducible nitric oxide synthase.

  17. A hypoxia-inducible factor (HIF)-3α splicing variant, HIF-3α4 impairs angiogenesis in hypervascular malignant meningiomas with epigenetically silenced HIF-3α4

    Energy Technology Data Exchange (ETDEWEB)

    Ando, Hitoshi [Department of Neurosurgery, Nagoya University School of Medicine, Nagoya (Japan); Department of Neurosurgery, Fukushima Medical University School of Medicine, Fukushima (Japan); Natsume, Atsushi, E-mail: anatsume@med.nagoya-u.ac.jp [Department of Neurosurgery, Nagoya University School of Medicine, Nagoya (Japan); Iwami, Kenichiro; Ohka, Fumiharu [Department of Neurosurgery, Nagoya University School of Medicine, Nagoya (Japan); Kuchimaru, Takahiro; Kizaka-Kondoh, Shinae [Department of Biomolecular Engineering, Tokyo Institute of Technology Graduate School of Bioscience and Biotechnology, Yokohama (Japan); Ito, Kengo [National Center for Geriatrics and Gerontology, Aichi (Japan); Saito, Kiyoshi [Department of Neurosurgery, Fukushima Medical University School of Medicine, Fukushima (Japan); Sugita, Sachi; Hoshino, Tsuneyoshi [MICRON Inc.Medical Facilities Support Department, Aichi (Japan); Wakabayashi, Toshihiko [Department of Neurosurgery, Nagoya University School of Medicine, Nagoya (Japan)

    2013-03-29

    Highlights: ► HIF-3α4 is silenced by DNA methylation in meningiomas. ► Induction of HIF-3α4 impaired angiogenesis in meningiomas. ► Induction of HIF-3α4 impaired proliferation and oxygen-dependent metabolism. -- Abstract: Hypoxia inducible factor is a dominant regulator of adaptive cellular responses to hypoxia and controls the expression of a large number of genes regulating angiogenesis as well as metabolism, cell survival, apoptosis, and other cellular functions in an oxygen level-dependent manner. When a neoplasm is able to induce angiogenesis, tumor progression occurs more rapidly because of the nutrients provided by the neovasculature. Meningioma is one of the most hypervascular brain tumors, making anti-angiogenic therapy an attractive novel therapy for these tumors. HIF-3α has been conventionally regarded as a dominant-negative regulator of HIF-1α, and although alternative HIF-3α splicing variants are extensively reported, their specific functions have not yet been determined. In this study, we found that the transcription of HIF-3α4 was silenced by the promoter DNA methylation in meningiomas, and inducible HIF-3α4 impaired angiogenesis, proliferation, and metabolism/oxidation in hypervascular meningiomas. Thus, HIF-3α4 could be a potential molecular target in meningiomas.

  18. A hypoxia-inducible factor (HIF)-3α splicing variant, HIF-3α4 impairs angiogenesis in hypervascular malignant meningiomas with epigenetically silenced HIF-3α4

    International Nuclear Information System (INIS)

    Ando, Hitoshi; Natsume, Atsushi; Iwami, Kenichiro; Ohka, Fumiharu; Kuchimaru, Takahiro; Kizaka-Kondoh, Shinae; Ito, Kengo; Saito, Kiyoshi; Sugita, Sachi; Hoshino, Tsuneyoshi; Wakabayashi, Toshihiko

    2013-01-01

    Highlights: ► HIF-3α4 is silenced by DNA methylation in meningiomas. ► Induction of HIF-3α4 impaired angiogenesis in meningiomas. ► Induction of HIF-3α4 impaired proliferation and oxygen-dependent metabolism. -- Abstract: Hypoxia inducible factor is a dominant regulator of adaptive cellular responses to hypoxia and controls the expression of a large number of genes regulating angiogenesis as well as metabolism, cell survival, apoptosis, and other cellular functions in an oxygen level-dependent manner. When a neoplasm is able to induce angiogenesis, tumor progression occurs more rapidly because of the nutrients provided by the neovasculature. Meningioma is one of the most hypervascular brain tumors, making anti-angiogenic therapy an attractive novel therapy for these tumors. HIF-3α has been conventionally regarded as a dominant-negative regulator of HIF-1α, and although alternative HIF-3α splicing variants are extensively reported, their specific functions have not yet been determined. In this study, we found that the transcription of HIF-3α4 was silenced by the promoter DNA methylation in meningiomas, and inducible HIF-3α4 impaired angiogenesis, proliferation, and metabolism/oxidation in hypervascular meningiomas. Thus, HIF-3α4 could be a potential molecular target in meningiomas

  19. Hypoxia Induces Epithelial-Mesenchymal Transition in Follicular Thyroid Cancer: Involvement of Regulation of Twist by Hypoxia Inducible Factor-1α.

    Science.gov (United States)

    Yang, Yeon Ju; Na, Hwi Jung; Suh, Michelle J; Ban, Myung Jin; Byeon, Hyung Kwon; Kim, Won Shik; Kim, Jae Wook; Choi, Eun Chang; Kwon, Hyeong Ju; Chang, Jae Won; Koh, Yoon Woo

    2015-11-01

    Although follicular thyroid cancer (FTC) has a relatively fair prognosis, distant metastasis sometimes results in poor prognosis and survival. There is little understanding of the mechanisms contributing to the aggressiveness potential of thyroid cancer. We showed that hypoxia inducible factor-1α (HIF-1α) induced aggressiveness in FTC cells and identified the underlying mechanism of the HIF-1α-induced invasive characteristics. Cells were cultured under controlled hypoxic environments (1% O₂) or normoxic conditions. The effect of hypoxia on HIF-1α, and epithelial-to-mesenchymal transition (EMT) related markers were evaluated by quantitative real-time PCR, Western blot analysis and immunocytochemistry. Invasion and wound healing assay were conducted to identify functional character of EMT. The involvement of HIF-1α and Twist in EMT were studied using gene overexpression or silencing. After orthotopic nude mouse model was established using the cells transfected with lentiviral shHIF-1α, tissue analysis was done. Hypoxia induces HIF-1α expression and EMT, including typical morphologic changes, cadherin shift, and increased vimentin expression. We showed that overexpression of HIF-1α via transfection resulted in the aforementioned changes without hypoxia, and repression of HIF-1α with RNA interference suppressed hypoxia-induced HIF-1α and EMT. Furthermore, we also observed that Twist expression was regulated by HIF-1α. These were confirmed in the orthotopic FTC model. Hypoxia induced HIF-1α, which in turn induced EMT, resulting in the increased capacity for invasion and migration of cells via regulation of the Twist signal pathway in FTC cells. These findings provide insight into a possible therapeutic strategy to prevent invasive and metastatic FTC.

  20. Hypoxia-inducible factor-1 plays a role in phosphate-induced vascular smooth muscle cell calcification.

    Science.gov (United States)

    Mokas, Sophie; Larivière, Richard; Lamalice, Laurent; Gobeil, Stéphane; Cornfield, David N; Agharazii, Mohsen; Richard, Darren E

    2016-09-01

    Medial vascular calcification is a common complication of chronic kidney disease (CKD). Although elevated inorganic phosphate stimulates vascular smooth muscle cell (VSMC) osteogenic transdifferentiation and calcification, the mechanisms involved in their calcification during CKD are not fully defined. Because hypoxic gene activation is linked to CKD and stimulates bone cell osteogenic differentiation, we used in vivo and in vitro rodent models to define the role of hypoxic signaling during elevated inorganic phosphate-induced VSMC calcification. Cell mineralization studies showed that elevated inorganic phosphate rapidly induced VSMC calcification. Hypoxia strongly enhanced elevated inorganic phosphate-induced VSMC calcification and osteogenic transdifferentiation, as seen by osteogenic marker expression. Hypoxia-inducible factor-1 (HIF-1), the key hypoxic transcription factor, was essential for enhanced VSMC calcification. Targeting HIF-1 expression in murine VSMC blocked calcification in hypoxia with elevated inorganic phosphate while HIF-1 activators, including clinically used FG-4592/Roxadustat, recreated a procalcifying environment. Elevated inorganic phosphate rapidly activated HIF-1, even in normal oxygenation; an effect mediated by HIF-1α subunit stabilization. Thus, hypoxia synergizes with elevated inorganic phosphate to enhance VSMC osteogenic transdifferentiation. Our work identifies HIF-1 as an early CKD-related pathological event, prospective marker, and potential target against vascular calcification in CKD-relevant conditions. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

  1. Saururus cernuus lignans-Potent small molecule inhibitors of hypoxia-inducible factor-1

    International Nuclear Information System (INIS)

    Hossain, Chowdhury Faiz; Kim, Yong-Pil; Baerson, Scott R.; Zhang Lei; Bruick, Richard K.; Mohammed, Kaleem A.; Agarwal, Ameeta K.; Nagle, Dale G.; Zhou Yudong

    2005-01-01

    Hypoxia-inducible factor-1 (HIF-1) represents an important tumor-selective therapeutic target for solid tumors. In search of novel small molecule HIF-1 inhibitors, 5400 natural product-rich extracts from plants, marine organisms, and microbes were examined for HIF-1 inhibitory activities using a cell-based reporter assay. Bioassay-guided fractionation and isolation, followed by structure elucidation, yielded three potent natural product-derived HIF-1 inhibitors and two structurally related inactive compounds. In a T47D cell-based reporter assay, manassantin B 1 , manassantin A, and 4-O-methylsaucerneol inhibited hypoxia-induced HIF-1 activation with IC 50 values of 3, 3, and 20 nM, respectively. All three compounds are relatively hypoxia-specific inhibitors of HIF-1 activation, in comparison to other stimuli. The hypoxic induction of HIF-1 target genes CDKN1A, VEGF, and GLUT-1 were also inhibited. These compounds inhibit HIF-1 by blocking hypoxia-induced nuclear HIF-1α protein accumulation without affecting HIF-1α mRNA levels. In addition, preliminary structure-activity studies suggest specific structural requirements for this class of HIF-1 inhibitors

  2. Hypoxia-inducible factor-1α upregulation in microglia following hypoxia protects against ischemia-induced cerebral infarction.

    Science.gov (United States)

    Huang, Tao; Huang, Weiyi; Zhang, Zhiqiang; Yu, Lei; Xie, Caijun; Zhu, Dongan; Peng, Zizhuang; Chen, Jiehan

    2014-10-01

    Activated microglia were considered to be the toxic inflammatory mediators that induce neuron degeneration after brain ischemia. Hypoxia can enhance the expression of hypoxia-inducible factor-1α (HIF-1α) in microglia and cause microglial activation. However, intermittent hypoxia has been reported recently to be capable of protecting the body from myocardial ischemia. We established a high-altitude environment as the hypoxic condition in this study. The hypoxic condition displayed a neuroprotective effect after brain ischemia, and mice exposed to this condition presented better neurological performance and smaller infarct size. At the same time, a high level of HIF-1α, low level of isoform of nitric oxide synthase, and a reduction in microglial activation were also seen in ischemic focus of hypoxic mice. However, this neuroprotective effect could be blocked by 2-methoxyestradiol, the HIF-1α inhibitor. Our finding suggested that HIF-1α expression was involved in microglial activation in vitro and was regulated by oxygen supply. The microglia were inactivated by re-exposure to hypoxia, which might be due to overexpression of HIF-1α. These results indicated that hypoxic conditions can be exploited to achieve maximum neuroprotection after brain ischemia. This mechanism possibly lies in microglial inactivation through regulation of the expression of HIF-1α.

  3. Hypoxia-Inducible Factor 3 Is an Oxygen-Dependent Transcription Activator and Regulates a Distinct Transcriptional Response to Hypoxia

    Directory of Open Access Journals (Sweden)

    Peng Zhang

    2014-03-01

    Full Text Available Hypoxia-inducible factors (HIFs play key roles in the cellular response to hypoxia. It is widely accepted that whereas HIF-1 and HIF-2 function as transcriptional activators, HIF-3 inhibits HIF-1/2α action. Contrary to this idea, we show that zebrafish Hif-3α has strong transactivation activity. Hif-3α is degraded under normoxia. Mutation of P393, P493, and L503 inhibits this oxygen-dependent degradation. Transcriptomics and chromatin immunoprecipitation analyses identify genes that are regulated by Hif-3α, Hif-1α, or both. Under hypoxia or when overexpressed, Hif-3α binds to its target gene promoters and upregulates their expression. Dominant-negative inhibition and knockdown of Hif-3α abolish hypoxia-induced Hif-3α-promoter binding and gene expression. Hif-3α not only mediates hypoxia-induced growth and developmental retardation but also possesses hypoxia-independent activities. Importantly, transactivation activity is conserved and human HIF-3α upregulates similar genes in human cells. These findings suggest that Hif-3 is an oxygen-dependent transcription factor and activates a distinct transcriptional response to hypoxia.

  4. Hypoxia and hypoxia inducible factor-1α are required for normal endometrial repair during menstruation.

    Science.gov (United States)

    Maybin, Jacqueline A; Murray, Alison A; Saunders, Philippa T K; Hirani, Nikhil; Carmeliet, Peter; Critchley, Hilary O D

    2018-01-23

    Heavy menstrual bleeding (HMB) is common and debilitating, and often requires surgery due to hormonal side effects from medical therapies. Here we show that transient, physiological hypoxia occurs in the menstrual endometrium to stabilise hypoxia inducible factor 1 (HIF-1) and drive repair of the denuded surface. We report that women with HMB have decreased endometrial HIF-1α during menstruation and prolonged menstrual bleeding. In a mouse model of simulated menses, physiological endometrial hypoxia occurs during bleeding. Maintenance of mice under hyperoxia during menses decreases HIF-1α induction and delays endometrial repair. The same effects are observed upon genetic or pharmacological reduction of endometrial HIF-1α. Conversely, artificial induction of hypoxia by pharmacological stabilisation of HIF-1α rescues the delayed endometrial repair in hypoxia-deficient mice. These data reveal a role for HIF-1 in the endometrium and suggest its pharmacological stabilisation during menses offers an effective, non-hormonal treatment for women with HMB.

  5. Hypoxia-Inducible Factor-1 as a Therapeutic Target in Endometrial Cancer Management

    Directory of Open Access Journals (Sweden)

    Laura M. S. Seeber

    2010-01-01

    Full Text Available In the Western world, endometrial cancer (EC is the most common malignant tumor of the female genital tract. Solid tumors like EC outgrow their vasculature resulting in hypoxia. Tumor hypoxia is important because it renders an aggressive phenotype and leads to radio- and chemo-therapy resistance. Hypoxia-inducible factor-1 (HIF-1 plays an essential role in the adaptive cellular response to hypoxia and is associated with poor clinical outcome in EC. Therefore, HIF-1 could be an attractive therapeutic target. Selective HIF-1 inhibitors have not been identified. A number of nonselective inhibitors which target signaling pathways upstream or downstream HIF-1 are known to decrease HIF-1 protein levels. In clinical trials for the treatment of advanced and/or recurrent EC are the topoisomerase I inhibitor Topotecan, mTOR-inhibitor Rapamycin, and angiogenesis inhibitor Bevacizumab. Preliminary data shows encouraging results for these agents. Further work is needed to identify selective HIF-1 inhibitors and to translate these into clinical trials.

  6. Hypoxia-Inducible Factor-1α in carcinogenesis and progression of breast cancer

    NARCIS (Netherlands)

    Bos, R.

    2004-01-01

    This thesis is primarily focused on the previously hardly explored role of HIF-1 in breast cancer. HIF-1 is a transcription factor induced by hypoxia, but also by some oncogenes, tumor suppressor genes and growth factors. Activated HIF-1 can induce angiogenesis, glycolysis, erythropoiesis, and other

  7. Regulation of hypoxia-inducible factor-1α (HIF-1α expression by interleukin-1β (IL-1 β, insulin-like growth factors I (IGF-I and II (IGF-II in human osteoarthritic chondrocytes

    Directory of Open Access Journals (Sweden)

    Angelica Rossi Sartori-Cintra

    2012-01-01

    Full Text Available OBJECTIVE: Hypoxia-inducible factor 1 alpha regulates genes related to cellular survival under hypoxia. This factor is present in osteroarthritic chondrocytes, and cytokines, such as interleukin-1 beta, participate in the pathogenesis of osteoarthritis, thereby increasing the activities of proteolytic enzymes, such as matrix metalloproteinases, and accelerating cartilage destruction. We hypothesize that Hypoxia Inducible Factor-1 alpha (HIF-1α can regulate cytokines (catabolic action and/or growth factors (anabolic action in osteoarthritis. The purpose of this study was to investigate the modulation of HIF-1α in human osteoarthritic chondrocytes by interleukin-1 beta (IL-1β and insulin-like growth factors I (IGF-I and II (IGF-II and to determine the involvement of the phosphatidylinositol-3kinase (PI-3K pathway in this process. METHODS: Human osteroarthritic chondrocytes were stimulated with IL-1β, IGF-I and IGF-II and LY294002, a specific inhibitor of PI-3K. Nuclear protein levels and gene expression were analyzed by western blot and quantitative reverse transcription-polymerase chain reaction analyses, respectively. RESULTS: HIF-1α expression was upregulated by IL-1β at the protein level but not at the gene level. IGF-I treatment resulted in increases in both the protein and mRNA levels of HIF-1α , whereas IGF-II had no effect on its expression. However, all of these stimuli exploited the PI-3K pathway. CONCLUSION: IL-1β upregulated the levels of HIF-1α protein post-transcriptionally, whereas IGF-I increased HIF-1α at the transcript level. In contrast, IGF-II did not affect the protein or gene expression levels of HIF-1α . Furthermore, all of the tested stimuli exploited the PI-3K pathway to some degree. Based on these findings, we are able to suggest that Hypoxia inducible Factor-1 exhibits protective activity in chondrocytes during osteoarthritis.

  8. Diacetoxyscirpenol as a new anticancer agent to target hypoxia-inducible factor 1

    Science.gov (United States)

    Choi, Yong-Joon; Shin, Hyun-Woo; Chun, Yang-Sook; Leutou, Alain Simplice; Son, Byeng Wha; Park, Jong-Wan

    2016-01-01

    Hypoxia activates hypoxia-inducible factor 1, which promotes the progression of malignancy by stimulating angiogenesis and by augmenting the ability of tumors to survive. Thus, HIF-1 is one of the most compelling targets for treating cancers. The aim of this study was to find a small molecule that inhibits HIF-1 under hypoxia in cancer cells. 7,280 compounds in a chemical library were tested in a cancer cell line expressing luciferase HIF-dependently. Through three rounds of screening, we finally picked up a compound that originates from a marine bacterium parasitizing red alga. The antibiotic potently inhibited HIF-1 expression and its transcriptional activity in cancer cells exposed to hypoxia. Through two-step fractionation, diacetoxyscirpenol was purified and identified as a HIF-inhibiting ingredient. Mechanistically, diacetoxyscirpenol inhibits the synthesis of HIF-1α protein and also interferes with the dimerization of HIF-1α and ARNT. It attenuates HIF-mediated gene expression in cancer cells exposed to hypoxia, and by doing so reduces tumorigenic and angiogenic potentials of cancer cells. More importantly, diacetoxyscirpenol retarded tumor growth in mice, and reduced HIF-1α expression and vascular formation in the tumors. Overall, diacetoxyscirpenol is considered a potential drug deregulating the HIF-1 signaling pathway, and it could be beneficially employed for treating malignant tumors with hypoxic microenvironment. PMID:27613833

  9. Hypoxia regulates the expression of the neuromedin B receptor through a mechanism dependent on hypoxia-inducible factor-1α.

    Directory of Open Access Journals (Sweden)

    Hyun-Joo Park

    Full Text Available The neuromedin B receptor (NMB-R, a member of the mammalian bombesin receptor family, is frequently overexpressed in various tumors. In the present study, we found that exposure to hypoxic conditions increases the levels of NMBR mRNA and protein in breast cancer cells, which are tightly regulated by hypoxia-inducible factor-1α (HIF-1α. We confirmed the effect of HIF-1α on NMBR transcription by performing an NMBR promoter-driven reporter assay and then identified a functional hypoxia-responsive element (HRE in the human NMBR promoter region. Further, the binding of HIF-1α to the NMBR promoter was corroborated by electrophoretic mobility shift and chromatin immunoprecipitation assays, which showed that HIF-1α specifically and directly bound to the NMBR promoter in response to hypoxia. Immunohistochemical analysis of a xenograft and a human breast cancer tissue array revealed a significant correlation between NMB-R and HIF-1α expression. Taken together, our findings indicate that hypoxia induces NMB-R expression through a novel mechanism to regulate HIF-1α expression in breast cancer cells.

  10. The role of hypoxia inducible factor-1 alpha in bypassing oncogene-induced senescence.

    Directory of Open Access Journals (Sweden)

    Mehtap Kilic Eren

    Full Text Available Oncogene induced senescence (OIS is a sustained anti-proliferative response acutely induced in primary cells via activation of mitogenic oncogenes such as Ras/BRAF. This mechanism acts as an initial barrier preventing normal cells transformation into malignant cell. Besides oncogenic activation and DNA damage response (DDR, senescence is modulated by a plethora of other factors, and one of the most important one is oxygen tension of the tissue. The aim of this study was to determine the impact of hypoxia on RasV12-induced senescence in human diploid fibroblasts (HDFs. We showed here that hypoxia prevents execution of oncogene induced senescence (OIS, through a strong down-regulation of senescence hallmarks, such as SA- β-galactosidase, H3K9me3, HP1γ, p53, p21CIP1 and p16INK4a in association with induction of hypoxia inducible factor-1α (HIF-1α. In addition, hypoxia also decreased marks of H-RasV12-induced DDR in both cell lines through down-regulation of ATM/ATR, Chk1 and Chk2 phosphorylation as well as decreased γ-H2AX positivity. Utilizing shRNA system targeting HIF-1α we show that HIF-1α is directly involved in down regulation of p53 and its target p21CIP1 but not p16INK4a. In line with this finding we found that knock down of HIF-1α leads to a strong induction of apoptotic response, but not restoration of senescence in Ras expressing HDFs in hypoxia. This indicates that HIF-1α is an important player in early steps of tumorigenesis, leading to suppression of senescence through its negative regulation of p53 and p21CIP1. In our work we describe a mechanism through which hypoxia and specifically HIF-1α preclude cells from maintaining senescence-driven anti proliferative response. These findings indicate the possible mechanism through which hypoxic environment helps premalignant cells to evade impingement of cellular failsafe pathways.

  11. MiR-142 modulates human pancreatic cancer proliferation and invasion by targeting hypoxia-inducible factor 1 (HIF-1α in the tumor microenvironments

    Directory of Open Access Journals (Sweden)

    Yebin Lu

    2017-02-01

    Full Text Available MicroRNAs regulate most protein-coding genes, including genes important in cancer and other diseases. In this study, we demonstrated that the expression of miR-142 could be significantly suppressed in pancreatic cancer specimens and cell lines compared to their adjacent tissues and normal pancreatic cells. Growth and invasion of PANC-1 and SW1990 cells were attenuated by overexpression of miR-142 in vitro. With the help of bioinformatics analysis, hypoxia-inducible factor 1 (HIF-1α was identified to be a direct target of miR-142, and a luciferase reporter experiment confirmed this discovery. Overexpression of miR-142 decreases protein expression of HIF-1α. In the hypoxic microenvironment, HIF-1α was up-regulated while miR-142 was down-regulated. The invaded cells significantly increased in the hypoxic microenvironment compared to the normoxic microenvironment. The hypoxia treatment induced cells’ proliferation, and invasion could be inhibited by miR-142 overexpression or HIF-1α inhibition. Moreover, expression of epithelial-mesenchymal transition (EMT markers, Vimentin, VEGF-C and E-cad, was altered under hypoxia conditions and regulated by miR-142/HIF-1α. Above all, these findings provided insights on the functional mechanism of miR-142, suggesting that the miR-142/HIF-1α axis may interfere with the proliferative and invasive properties of pancreatic cancer cells, and indicated that miR-142 could be a potential therapeutic target for pancreatic cancer.

  12. Hypoxia-independent upregulation of placental hypoxia inducible factor-1α gene expression contributes to the pathogenesis of preeclampsia.

    Science.gov (United States)

    Iriyama, Takayuki; Wang, Wei; Parchim, Nicholas F; Song, Anren; Blackwell, Sean C; Sibai, Baha M; Kellems, Rodney E; Xia, Yang

    2015-06-01

    Accumulation of hypoxia inducible factor-1α (HIF-1α) is commonly an acute and beneficial response to hypoxia, whereas chronically elevated HIF-1α is associated with multiple disease conditions, including preeclampsia, a serious hypertensive disease of pregnancy. However, the molecular basis underlying the persistent elevation of placental HIF-1α in preeclampsia and its role in the pathogenesis of preeclampsia are poorly understood. Here we report that Hif-1α mRNA and HIF-1α protein were elevated in the placentas of pregnant mice infused with angiotensin II type I receptor agonistic autoantibody, a pathogenic factor in preeclampsia. Knockdown of placental Hif-1α mRNA by specific siRNA significantly attenuated hallmark features of preeclampsia induced by angiotensin II type I receptor agonistic autoantibody in pregnant mice, including hypertension, proteinuria, kidney damage, impaired placental vasculature, and elevated maternal circulating soluble fms-like tyrosine kinase-1 levels. Next, we discovered that Hif-1α mRNA levels and HIF-1α protein levels were induced in an independent preeclampsia model with infusion of the inflammatory cytokine tumor necrosis factor superfamily member 14 (LIGHT). SiRNA knockdown experiments also demonstrated that elevated HIF-1α contributed to LIGHT-induced preeclampsia features. Translational studies with human placentas showed that angiotensin II type I receptor agonistic autoantibody or LIGHT is capable of inducing HIF-1α in a hypoxia-independent manner. Moreover, increased HIF-1α was found to be responsible for angiotensin II type I receptor agonistic autoantibody or LIGHT-induced elevation of Flt-1 gene expression and production of soluble fms-like tyrosine kinase-1 in human villous explants. Overall, we demonstrated that hypoxia-independent stimulation of HIF-1α gene expression in the placenta is a common pathogenic mechanism promoting disease progression. Our findings reveal new insight to preeclampsia and highlight

  13. Epigenetic control of hypoxia inducible factor-1α-dependent expression of placental growth factor in hypoxic conditions.

    Science.gov (United States)

    Tudisco, Laura; Della Ragione, Floriana; Tarallo, Valeria; Apicella, Ivana; D'Esposito, Maurizio; Matarazzo, Maria Rosaria; De Falco, Sandro

    2014-04-01

    Hypoxia plays a crucial role in the angiogenic switch, modulating a large set of genes mainly through the activation of hypoxia-inducible factor (HIF) transcriptional complex. Endothelial cells play a central role in new vessels formation and express placental growth factor (PlGF), a member of vascular endothelial growth factor (VEGF) family, mainly involved in pathological angiogenesis. Despite several observations suggest a hypoxia-mediated positive modulation of PlGF, the molecular mechanism governing this regulation has not been fully elucidated. We decided to investigate if epigenetic modifications are involved in hypoxia-induced PlGF expression. We report that PlGF expression was induced in cultured human and mouse endothelial cells exposed to hypoxia (1% O 2), although DNA methylation at the Plgf CpG-island remains unchanged. Remarkably, robust hyperacetylation of histones H3 and H4 was observed in the second intron of Plgf, where hypoxia responsive elements (HREs), never described before, are located. HIF-1α, but not HIF-2α, binds to identified HREs. Noteworthy, only HIF-1α silencing fully inhibited PlGF upregulation. These results formally demonstrate a direct involvement of HIF-1α in the upregulation of PlGF expression in hypoxia through chromatin remodeling of HREs sites. Therefore, PlGF may be considered one of the putative targets of anti-HIF therapeutic applications.

  14. Hypoxia and hypoglycaemia in Ewing's sarcoma and osteosarcoma: regulation and phenotypic effects of Hypoxia-Inducible Factor.

    Science.gov (United States)

    Knowles, Helen J; Schaefer, Karl-Ludwig; Dirksen, Uta; Athanasou, Nicholas A

    2010-07-16

    Hypoxia regulates gene expression via the transcription factor HIF (Hypoxia-Inducible Factor). Little is known regarding HIF expression and function in primary bone sarcomas. We describe HIF expression and phenotypic effects of hypoxia, hypoglycaemia and HIF in Ewing's sarcoma and osteosarcoma. HIF-1alpha and HIF-2alpha immunohistochemistry was performed on a Ewing's tumour tissue array. Ewing's sarcoma and osteosarcoma cell lines were assessed for HIF pathway induction by Western blot, luciferase assay and ELISA. Effects of hypoxia, hypoglycaemia and isoform-specific HIF siRNA were assessed on proliferation, apoptosis and migration. 17/56 Ewing's tumours were HIF-1alpha-positive, 15 HIF-2alpha-positive and 10 positive for HIF-1alpha and HIF-2alpha. Expression of HIF-1alpha and cleaved caspase 3 localised to necrotic areas. Hypoxia induced HIF-1alpha and HIF-2alpha in Ewing's and osteosarcoma cell lines while hypoglycaemia specifically induced HIF-2alpha in Ewing's. Downstream transcription was HIF-1alpha-dependent in Ewing's sarcoma, but regulated by both isoforms in osteosarcoma. In both cell types hypoglycaemia reduced cellular proliferation by >or= 45%, hypoxia increased apoptosis and HIF siRNA modulated hypoxic proliferation and migration. Co-localisation of HIF-1alpha and necrosis in Ewing's sarcoma suggests a role for hypoxia and/or hypoglycaemia in in vivo induction of HIF. In vitro data implicates hypoxia as the primary HIF stimulus in both Ewing's and osteosarcoma, driving effects on proliferation and apoptosis. These results provide a foundation from which to advance understanding of HIF function in the pathobiology of primary bone sarcomas.

  15. Hypoxia-inducible factor-1 signalling promotes goblet cell hyperplasia in airway epithelium

    Science.gov (United States)

    Polosukhin, Vasiliy V; Cates, Justin M; Lawson, William E; Milstone, Aaron P; Matafonov, Anton G; Massion, Pierre P; Lee, Jae Woo; Randell, Scott H; Blackwell, Timothy S

    2018-01-01

    Goblet cell hyperplasia is a common feature of chronic obstructive pulmonary disease (COPD) airways, but the mechanisms that underlie this epithelial remodelling in COPD are not understood. Based on our previous finding of hypoxia-inducible factor-1α (HIF-1α) nuclear localization in large airways from patients with COPD, we investigated whether hypoxia-inducible signalling could influence the development of goblet cell hyperplasia. We evaluated large airway samples obtained from 18 lifelong non-smokers and 13 former smokers without COPD, and 45 former smokers with COPD. In these specimens, HIF-1α nuclear staining occurred almost exclusively in COPD patients in areas of airway remodelling. In COPD patients, 93.2 ± 3.9% (range 65 – 100%) of goblet cells were HIF-1α positive in areas of goblet cell hyperplasia, whereas nuclear HIF-1α was not detected in individuals without COPD or in normal-appearing pseudostratified epithelium from COPD patients. To determine the direct effects of hypoxia-inducible signalling on epithelial cell differentiation in vitro, human bronchial epithelial cells (HBECs) were grown in air-liquid interface cultures under hypoxia (1% O2) or following treatment with a selective HIF-1α stabilizer, (2R)-[(4-biphenylylsulphonyl)amino]-N-hydroxy-3-phenyl-propionamide (BiPS). HBECs grown in hypoxia or with BiPS treatment were characterized by HIF-1α activation, carbonic anhydrase IX expression, mucus-producing cell hyperplasia and increased expression of MUC5AC. Analysis of signal transduction pathways in cells with HIF-1α activation showed increased ERK1/2 phosphorylation without activation of epidermal growth factor receptor, Ras, PI3K-Akt or STAT6. These data indicate an important effect of hypoxia-inducible signalling on airway epithelial cell differentiation and identify a new potential target to limit mucus production in COPD. PMID:21557221

  16. Role of hypoxia and hypoxia inducible factor in physiological and pathological conditions

    Directory of Open Access Journals (Sweden)

    Mozhgan Jahani

    2017-11-01

    Full Text Available Introduction: Organisms are exposed to oxygen deprivation (Hypoxia in various physiological and pathological conditions. There are different conserve evolutionary responses to counterview with this stress that primary transcriptional response to stress related to hypoxia is interceded by hypoxia-inducible factor (HIF-1 in mammals. This factor can regulate different genes that have essential roles in adaptation to this condition. In this review, the role of this factor in physiological and pathological conditions under hypoxic condition has been evaluated after examining structural features and regulation characteristics of HIF-1. Methods: First, articles related to the keywords of hypoxia and HIF-1 (from 1991-2016 were searched from valid databases such as Springer Link, Google Scholar, PubMed and Science direct. Then, the articles correlated with hypoxia, HIF-1 and their roles in physiological and pathological conditions (120 articles were searched and just 64 articles were selected for this study. Result: According to studies, there are different genes in cells and organs that can be regulated by HIF-1. Activation of genes expression by this protein occurs through its linkage to cis-acting of 50 base pair hypoxia response element (HRE region located in their promotor and enhancer. Depending on circumstances, activation of these genes can be beneficial or harmful. Conclusion: Activation of different genes in hypoxia by HIF-1 has different effects on physiological and pathological conditions. Therefore, HIF-1, as a hypoxia-inducible factor in hypoxic conditions, plays an essential role in the adaptation of cells and organs to changes related to the presence of oxygen.

  17. Eukaryotic translation initiation factor 5A (eIF5A) is essential for HIF-1α activation in hypoxia

    Energy Technology Data Exchange (ETDEWEB)

    Tariq, Mohammad [Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Graduate School of Science and Engineering, Saitama University, 645 Shimo-Okubo, Sakura-ku, Saitama 338-8570 (Japan); Ito, Akihiro, E-mail: akihiro-i@riken.jp [Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Chemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Japan Agency for Medical Research and Development, AMED-CREST, 1-7-1 Otemachi, Chiyoda-ku, Tokyo, 100-0004 (Japan); Ishfaq, Muhammad; Bradshaw, Elliot [Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Graduate School of Science and Engineering, Saitama University, 645 Shimo-Okubo, Sakura-ku, Saitama 338-8570 (Japan); Yoshida, Minoru [Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Chemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Graduate School of Science and Engineering, Saitama University, 645 Shimo-Okubo, Sakura-ku, Saitama 338-8570 (Japan); Japan Agency for Medical Research and Development, AMED-CREST, 1-7-1 Otemachi, Chiyoda-ku, Tokyo, 100-0004 (Japan)

    2016-02-05

    The eukaryotic initiation factor 5A (eIF5A) is an essential protein involved in translation elongation and cell proliferation. eIF5A undergoes several post-translational modifications including hypusination and acetylation. Hypusination is indispensable for the function of eIF5A. On the other hand, the precise function of acetylation remains unknown, but it may render the protein inactive since hypusination blocks acetylation. Here, we report that acetylation of eIF5A increases under hypoxia. During extended hypoxic periods an increase in the level of eIF5A acetylation correlated with a decrease in HIF-1α, suggesting involvement of eIF5A activity in HIF-1α expression under hypoxia. Indeed, suppression of eIF5A by siRNA oligo-mediated knockdown or treatment with GC7, a deoxyhypusine synthase inhibitor, led to significant reduction of HIF-1α activity. Furthermore, knockdown of eIF5A or GC7 treatment reduced tumor spheroid formation with a concomitant decrease in HIF-1α expression. Our results suggest that functional, hypusinated eIF5A is necessary for HIF-1α expression during hypoxia and that eIF5A is an attractive target for cancer therapy. - Highlights: • Hypoxia induces acetylation of eIF5A. • Active eIF5A is necessary for HIF-1α activation in hypoxia. • Active eIF5A is important for tumor spheroid growth.

  18. Eukaryotic translation initiation factor 5A (eIF5A) is essential for HIF-1α activation in hypoxia

    International Nuclear Information System (INIS)

    Tariq, Mohammad; Ito, Akihiro; Ishfaq, Muhammad; Bradshaw, Elliot; Yoshida, Minoru

    2016-01-01

    The eukaryotic initiation factor 5A (eIF5A) is an essential protein involved in translation elongation and cell proliferation. eIF5A undergoes several post-translational modifications including hypusination and acetylation. Hypusination is indispensable for the function of eIF5A. On the other hand, the precise function of acetylation remains unknown, but it may render the protein inactive since hypusination blocks acetylation. Here, we report that acetylation of eIF5A increases under hypoxia. During extended hypoxic periods an increase in the level of eIF5A acetylation correlated with a decrease in HIF-1α, suggesting involvement of eIF5A activity in HIF-1α expression under hypoxia. Indeed, suppression of eIF5A by siRNA oligo-mediated knockdown or treatment with GC7, a deoxyhypusine synthase inhibitor, led to significant reduction of HIF-1α activity. Furthermore, knockdown of eIF5A or GC7 treatment reduced tumor spheroid formation with a concomitant decrease in HIF-1α expression. Our results suggest that functional, hypusinated eIF5A is necessary for HIF-1α expression during hypoxia and that eIF5A is an attractive target for cancer therapy. - Highlights: • Hypoxia induces acetylation of eIF5A. • Active eIF5A is necessary for HIF-1α activation in hypoxia. • Active eIF5A is important for tumor spheroid growth.

  19. Cobalt-alloy implant debris induce HIF-1α hypoxia associated responses: a mechanism for metal-specific orthopedic implant failure.

    Directory of Open Access Journals (Sweden)

    Lauryn Samelko

    Full Text Available The historical success of orthopedic implants has been recently tempered by unexpected pathologies and early failures of some types of Cobalt-Chromium-Molybdenum alloy containing artificial hip implants. Hypoxia-associated responses to Cobalt-alloy metal debris were suspected as mediating this untoward reactivity at least in part. Hypoxia Inducible Factor-1α is a major transcription factor involved in hypoxia, and is a potent coping mechanism for cells to rapidly respond to changing metabolic demands. We measured signature hypoxia associated responses (i.e. HIF-1α, VEGF and TNF-α to Cobalt-alloy implant debris both in vitro (using a human THP-1 macrophage cell line and primary human monocytes/macrophages and in vivo. HIF-1α in peri-implant tissues of failed metal-on-metal implants were compared to similar tissues from people with metal-on-polymer hip arthroplasties, immunohistochemically. Increasing concentrations of cobalt ions significantly up-regulated HIF-1α with a maximal response at 0.3 mM. Cobalt-alloy particles (1 um-diameter, 10 particles/cell induced significantly elevated HIF-1α, VEGF, TNF-α and ROS expression in human primary macrophages whereas Titanium-alloy particles did not. Elevated expression of HIF-1α was found in peri-implant tissues and synovial fluid of people with failing Metal-on-Metal hips (n = 5 compared to failed Metal-on-Polymer articulating hip arthroplasties (n = 10. This evidence suggests that Cobalt-alloy, more than other metal implant debris (e.g. Titanium alloy, can elicit hypoxia-like responses that if unchecked can lead to unusual peri-implant pathologies, such as lymphocyte infiltration, necrosis and excessive fibrous tissue growths.

  20. A new pharmacological agent (AKB-4924) stabilizes hypoxia inducible factor-1 (HIF-1) and increases skin innate defenses against bacterial infection.

    Science.gov (United States)

    Okumura, Cheryl Y M; Hollands, Andrew; Tran, Dan N; Olson, Joshua; Dahesh, Samira; von Köckritz-Blickwede, Maren; Thienphrapa, Wdee; Corle, Courtney; Jeung, Seung Nam; Kotsakis, Anna; Shalwitz, Robert A; Johnson, Randall S; Nizet, Victor

    2012-09-01

    Hypoxia inducible factor-1 (HIF-1) is a transcription factor that is a major regulator of energy homeostasis and cellular adaptation to low oxygen stress. HIF-1 is also activated in response to bacterial pathogens and supports the innate immune response of both phagocytes and keratinocytes. In this work, we show that a new pharmacological compound AKB-4924 increases HIF-1 levels and enhances the antibacterial activity of phagocytes and keratinocytes against both methicillin-sensitive and methicillin-resistant strains of Staphylococcus aureus in vitro. AKB-4924 is also effective in stimulating the killing capacity of keratinocytes against the important opportunistic skin pathogens Pseudomonas aeruginosa and Acinetobacter baumanii. The effect of AKB-4924 is mediated through the activity of host cells, as the compound exerts no direct antimicrobial activity. Administered locally as a single agent, AKB-4924 limits S. aureus proliferation and lesion formation in a mouse skin abscess model. This approach to pharmacologically boost the innate immune response via HIF-1 stabilization may serve as a useful adjunctive treatment for antibiotic-resistant bacterial infections.

  1. Hypoxia-Independent Downregulation of Hypoxia-Inducible Factor 1 Targets by Androgen Deprivation Therapy in Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ragnum, Harald Bull [Department of Radiation Biology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Røe, Kathrine [Department of Radiation Biology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Division of Medicine, Department of Oncology, Akershus University Hospital, Lørenskog (Norway); Holm, Ruth; Vlatkovic, Ljiljana [Department of Pathology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Nesland, Jahn Marthin [Department of Pathology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Medical Faculty, University of Oslo, Oslo (Norway); Aarnes, Eva-Katrine [Department of Radiation Biology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Ree, Anne Hansen [Division of Medicine, Department of Oncology, Akershus University Hospital, Lørenskog (Norway); Medical Faculty, University of Oslo, Oslo (Norway); Flatmark, Kjersti [Department of Tumor Biology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Department of Gastrointestinal Surgery, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Seierstad, Therese [Department of Radiology and Nuclear Medicine, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Faculty of Health Sciences, Buskerud University College, Drammen (Norway); Lilleby, Wolfgang [Department of Oncology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Lyng, Heidi, E-mail: heidi.lyng@rr-research.no [Department of Radiation Biology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway)

    2013-11-15

    Purpose: We explored changes in hypoxia-inducible factor 1 (HIF1) signaling during androgen deprivation therapy (ADT) of androgen-sensitive prostate cancer xenografts under conditions in which no significant change in immunostaining of the hypoxia marker pimonidazole had occurred. Methods and Materials: Gene expression profiles of volume-matched androgen-exposed and androgen-deprived CWR22 xenografts, with similar pimonidazole-positive fractions, were compared. Direct targets of androgen receptor (AR) and HIF1 transcription factors were identified among the differentially expressed genes by using published lists. Biological processes affected by ADT were determined by gene ontology analysis. HIF1α protein expression in xenografts and biopsy samples from 35 patients receiving neoadjuvant ADT was assessed by immunohistochemistry. Results: A total of 1344 genes showed more than 2-fold change in expression by ADT, including 35 downregulated and 5 upregulated HIF1 targets. Six genes were shared HIF1 and AR targets, and their downregulation was confirmed with quantitative RT-PCR. Significant suppression of the biological processes proliferation, metabolism, and stress response in androgen-deprived xenografts was found, consistent with tumor regression. Nineteen downregulated HIF1 targets were involved in those significant biological processes, most of them in metabolism. Four of these were shared AR and HIF1 targets, including genes encoding the regulatory glycolytic proteins HK2, PFKFB3, and SLC2A1. Most of the downregulated HIF1 targets were induced by hypoxia in androgen-responsive prostate cancer cell lines, confirming their role as hypoxia-responsive HIF1 targets in prostate cancer. Downregulation of HIF1 targets was consistent with the absence of HIF1α protein in xenografts and downregulation in patients by ADT (P<.001). Conclusions: AR repression by ADT may lead to downregulation of HIF1 signaling independently of hypoxic fraction, and this may contribute to

  2. Hypoxia-Independent Downregulation of Hypoxia-Inducible Factor 1 Targets by Androgen Deprivation Therapy in Prostate Cancer

    International Nuclear Information System (INIS)

    Ragnum, Harald Bull; Røe, Kathrine; Holm, Ruth; Vlatkovic, Ljiljana; Nesland, Jahn Marthin; Aarnes, Eva-Katrine; Ree, Anne Hansen; Flatmark, Kjersti; Seierstad, Therese; Lilleby, Wolfgang; Lyng, Heidi

    2013-01-01

    Purpose: We explored changes in hypoxia-inducible factor 1 (HIF1) signaling during androgen deprivation therapy (ADT) of androgen-sensitive prostate cancer xenografts under conditions in which no significant change in immunostaining of the hypoxia marker pimonidazole had occurred. Methods and Materials: Gene expression profiles of volume-matched androgen-exposed and androgen-deprived CWR22 xenografts, with similar pimonidazole-positive fractions, were compared. Direct targets of androgen receptor (AR) and HIF1 transcription factors were identified among the differentially expressed genes by using published lists. Biological processes affected by ADT were determined by gene ontology analysis. HIF1α protein expression in xenografts and biopsy samples from 35 patients receiving neoadjuvant ADT was assessed by immunohistochemistry. Results: A total of 1344 genes showed more than 2-fold change in expression by ADT, including 35 downregulated and 5 upregulated HIF1 targets. Six genes were shared HIF1 and AR targets, and their downregulation was confirmed with quantitative RT-PCR. Significant suppression of the biological processes proliferation, metabolism, and stress response in androgen-deprived xenografts was found, consistent with tumor regression. Nineteen downregulated HIF1 targets were involved in those significant biological processes, most of them in metabolism. Four of these were shared AR and HIF1 targets, including genes encoding the regulatory glycolytic proteins HK2, PFKFB3, and SLC2A1. Most of the downregulated HIF1 targets were induced by hypoxia in androgen-responsive prostate cancer cell lines, confirming their role as hypoxia-responsive HIF1 targets in prostate cancer. Downregulation of HIF1 targets was consistent with the absence of HIF1α protein in xenografts and downregulation in patients by ADT (P<.001). Conclusions: AR repression by ADT may lead to downregulation of HIF1 signaling independently of hypoxic fraction, and this may contribute to

  3. Hypoxia and hypoglycaemia in Ewing's sarcoma and osteosarcoma: regulation and phenotypic effects of Hypoxia-Inducible Factor

    Directory of Open Access Journals (Sweden)

    Dirksen Uta

    2010-07-01

    Full Text Available Abstract Background Hypoxia regulates gene expression via the transcription factor HIF (Hypoxia-Inducible Factor. Little is known regarding HIF expression and function in primary bone sarcomas. We describe HIF expression and phenotypic effects of hypoxia, hypoglycaemia and HIF in Ewing's sarcoma and osteosarcoma. Methods HIF-1α and HIF-2α immunohistochemistry was performed on a Ewing's tumour tissue array. Ewing's sarcoma and osteosarcoma cell lines were assessed for HIF pathway induction by Western blot, luciferase assay and ELISA. Effects of hypoxia, hypoglycaemia and isoform-specific HIF siRNA were assessed on proliferation, apoptosis and migration. Results 17/56 Ewing's tumours were HIF-1α-positive, 15 HIF-2α-positive and 10 positive for HIF-1α and HIF-2α. Expression of HIF-1α and cleaved caspase 3 localised to necrotic areas. Hypoxia induced HIF-1α and HIF-2α in Ewing's and osteosarcoma cell lines while hypoglycaemia specifically induced HIF-2α in Ewing's. Downstream transcription was HIF-1α-dependent in Ewing's sarcoma, but regulated by both isoforms in osteosarcoma. In both cell types hypoglycaemia reduced cellular proliferation by ≥ 45%, hypoxia increased apoptosis and HIF siRNA modulated hypoxic proliferation and migration. Conclusions Co-localisation of HIF-1α and necrosis in Ewing's sarcoma suggests a role for hypoxia and/or hypoglycaemia in in vivo induction of HIF. In vitro data implicates hypoxia as the primary HIF stimulus in both Ewing's and osteosarcoma, driving effects on proliferation and apoptosis. These results provide a foundation from which to advance understanding of HIF function in the pathobiology of primary bone sarcomas.

  4. MicroRNA-195 induced apoptosis in hypoxic chondrocytes by targeting hypoxia-inducible factor 1 alpha.

    Science.gov (United States)

    Bai, R; Zhao, A-Q; Zhao, Z-Q; Liu, W-L; Jian, D-M

    2015-02-01

    The chondrocytes, the resident cells of cartilage, are maintained and take effects in the whole life upon chronic hypoxic exposure, which hypoxia-inducible factor 1 alpha (HIF-1α) play pivotal roles in response to. Dysregulation of some microRNA (miRNAs) have also been identified to be involved in hypoxia-related physiologic and pathophysiologic responses in some tissues or cell lines. However, the mechanism of miRNAs reponse to hypoxia remain largely unknown in chondrocytes, including the microRNA-195 (miR-195). AIM To investigate the effects of microRNAs (miRNAs) and hypoxia-inducible factor 1 alpha (HIF-1α) on chondrocytes in physiologic environment. We compared the expression of miR-195 and HIF-1α mRNA on hypoxia with that on normoxia in ATDC 5 cells by qRT-PCR. Further experiments was performed to confirmed the relationships of miR-195 and HIF-1α by bioinformatics analysis and dual reporter gene assay. we also assessed the effect of miR-195 on apoptosis in hypoxic ATDC 5 cells by transfect with miR-195 mimics. It was found the downregulated miR-195 and upregulated HIF-1α were present in hypoxic ATDC 5 cells. miR-195 negatively regulated HIF-1α by targeting its 3'-untranslated region. Moreover, the founding indicated miR-195 greatly increased apoptosis and downregulated HIF-1α mRNA occurred simultaneously in hypoxic chondrocytes. We concluded that miR-195 induced apoptosis in hypoxic chondrocytes by directly targeting HIF-1α.

  5. Hypoxia Inducible Factor 1 (HIF1) Activation in U87 Glioma Cells Involves a Decrease in Reactive Oxygen Species Production and Protein Kinase C Activity

    Science.gov (United States)

    1998-06-29

    Curcumin DFX Desferrioxamine DNA Deoxyribonucleic Acid DPI Diphenyliodinium DPPD Diphenylphenylenediamine DTH Dithionite EMSA Electrophoretic mobility shift... neuroprotective effects (Fern et al., 1996, Morishita et al., 1 1997). The identification of a hypoxia inducible transcription factor known as HIF-1 (Semenza...derived EPO in the eNS neuroprotective response to hypoxia. Cloning of the human and murine EPO gene, the availability of a convenient EPa producing

  6. Suppression of hypoxia inducible factor-1α (HIF-1α) by YC-1 is dependent on murine double minute 2 (Mdm2)

    International Nuclear Information System (INIS)

    Lau, C.K.; Yang, Z.F.; Lam, C.T.; Tam, K.H.; Poon, R.T.P.; Fan, S.T.

    2006-01-01

    Inhibition of HIF-1α activity provides an important strategy for the treatment of cancer. Recently, 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1) has been identified as an anti-HIF-1α drug in cancer therapy with unclear molecular mechanism. In the present study, we aimed to investigate the effect and mechanism of YC-1 on HIF-1α in a hepatocellular carcinoma cell line under hypoxic condition, which was generated by incubating cells with 0.1% O 2 . The phenotypic and molecular changes of cells were determined by cell proliferation assay, apoptosis assay, luciferase promoter assay, and Western blot analysis. YC-1 arrested tumor cell growth in a dose-dependent manner, whereas it did not induce cell apoptosis. Hypoxia-induced upregulation of HIF-1α was suppressed by YC-1 administration. YC-1 inhibited HIF-1α protein synthesis under normoxia and affected protein stability under hypoxia. YC-1 suppressed the expression of total and phosphorylated forms of murine double minute 2 (Mdm2), whereas this inhibitory effect was blocked by overexpression of Mdm2. In conclusion, YC-1 suppressed both protein synthesis and stability of HIF-1α in HCC cells, and its inhibitory effects on HIF-1α were dependent on Mdm2

  7. Hypoxia inducible factor 1-alpha (HIF-1 alpha is induced during reperfusion after renal ischemia and is critical for proximal tubule cell survival.

    Directory of Open Access Journals (Sweden)

    Elisa Conde

    Full Text Available Acute tubular necrosis (ATN caused by ischemia/reperfusion (I/R during renal transplantation delays allograft function. Identification of factors that mediate protection and/or epithelium recovery could help to improve graft outcome. We studied the expression, regulation and role of hypoxia inducible factor 1-alpha (HIF-1 α, using in vitro and in vivo experimental models of I/R as well as human post-transplant renal biopsies. We found that HIF-1 α is stabilized in proximal tubule cells during ischemia and unexpectedly in late reperfusion, when oxygen tension is normal. Both inductions lead to gene expression in vitro and in vivo. In vitro interference of HIF-1 α promoted cell death and in vivo interference exacerbated tissue damage and renal dysfunction. In pos-transplant human biopsies, HIF-1 α was expressed only in proximal tubules which exhibited normal renal structure with a significant negative correlation with ATN grade. In summary, using experimental models and human biopsies, we identified a novel HIF-1 α induction during reperfusion with a potential critical role in renal transplant.

  8. Low Molecular Weight Fucoidan Inhibits Tumor Angiogenesis through Downregulation of HIF-1/VEGF Signaling under Hypoxia

    Directory of Open Access Journals (Sweden)

    Meng-Chuan Chen

    2015-07-01

    Full Text Available Activation of hypoxia-induced hypoxia-inducible factors-1 (HIF-1 plays a critical role in promoting tumor angiogenesis, growth and metastasis. Low molecular weight fucoidan (LMWF is prepared from brown algae, and exhibits anticancer activity. However, whether LMWF attenuates hypoxia-induced angiogenesis in bladder cancer cells and the molecular mechanisms involved remain unclear. This is the first study to demonstrate that LMWF can inhibit hypoxia-stimulated H2O2 formation, HIF-1 accumulation and transcriptional activity vascular endothelial growth factor (VEGF secretion, and the migration and invasion in hypoxic human bladder cancer cells (T24 cells. LMWF also downregulated hypoxia-activated phosphorylation of PI3K/AKT/mTOR/p70S6K/4EBP-1 signaling in T24 cells. Blocking PI3K/AKT or mTOR activity strongly diminished hypoxia-induced HIF-1α expression and VEGF secretion in T24 cells, supporting the involvement of PI3K/AKT/mTOR in the induction of HIF-1α and VEGF. Additionally, LMWF significantly attenuated angiogenesis in vitro and in vivo evidenced by reduction of tube formation of hypoxic human umbilical vascular endothelial cells and blood capillary generation in the tumor. Similarly, administration of LMWF also inhibited the HIF-1α and VEGF expression in vivo, accompanied by a reduction of tumor growth. In summary, under hypoxia conditions, the antiangiogenic activity of LMWF in bladder cancer may be associated with suppressing HIF-1/VEGF-regulated signaling pathway.

  9. Expression of hypoxia-inducible factor-1 by trophectoderm cells in response to hypoxia and epidermal growth factor

    International Nuclear Information System (INIS)

    Jeong, Wooyoung; Bazer, Fuller W.; Song, Gwonhwa; Kim, Jinyoung

    2016-01-01

    The low oxygen environment in the uterine environment requires pre-implantation embryos to adapt to oxygen deficiency. Hypoxia-inducible factor (HIF)-1 is a master regulator whereby cells adapt to changes in oxygen concentrations. In addition to hypoxic conditions, non-hypoxic stimuli such as growth factors also activate expression of HIF-1. In this study, the mechanisms underlying low oxygen-dependent and epidermal growth factor (EGF)-dependent expression of HIF-1α were explored using porcine trophectoderm (pTr) cells. The results indicated that expression of HIF-1α and HIF-1β mRNAs was not affected by low concentrations of oxygen; however, hypoxic conditions markedly increased the abundance of HIF-1α protein, especially in nuclei of pTr cells. Even under normoxic conditions, the abundance of HIF-1α protein increased in response to EGF. This EGF-mediated increase in HIF-1α protein was blocked through inhibition of translation by cycloheximide. The inhibitors LY294002 (PI3K-AKT inhibitor), U0126 (inhibitor of ERK1/2) and rapamycin (mTOR inhibitor) also blocked the ability of EGF to increase HIF-1α protein and to phosphorylate AKT, ERK1/2 and mTOR proteins. Both hypoxia and EGF induced proliferation of pTr cells. This ability of EGF to stimulate proliferation of pTr cells was suppressed by EGFR siRNA, but not HIF-1α siRNA, but a significant decrease in EGF-induced HIF-1α protein occurred when pTr cells were transfected with HIF-1α siRNA. The results of the present study suggest that pTr cells adapt to oxygen deficiency and proliferate in response to an oxygen-dependent HIF-1 system, and that EGF at maternal–conceptus interface can increase the abundance of HIF-1α protein via translational regulation through AKT, ERK1/2 and mTOR signaling cascades. - Highlights: • HIF-1α expression is up-regulated in pTr cells under low oxygen concentrations. • EGF induces HIF-1α accumulation in pTr cells. • EGF-induced HIF-1α accumulation is blocked by de

  10. Expression of hypoxia-inducible factor-1 by trophectoderm cells in response to hypoxia and epidermal growth factor

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Wooyoung [Department of Animal Resources Science, Dankook University, Cheonan (Korea, Republic of); Bazer, Fuller W. [Center for Animal Biotechnology and Genomics and Department of Animal Science, Texas A& M University, College Station, TX (United States); Song, Gwonhwa, E-mail: ghsong@korea.ac.kr [Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul (Korea, Republic of); Kim, Jinyoung, E-mail: jinyoungkim@dankook.ac.kr [Department of Animal Resources Science, Dankook University, Cheonan (Korea, Republic of)

    2016-01-08

    The low oxygen environment in the uterine environment requires pre-implantation embryos to adapt to oxygen deficiency. Hypoxia-inducible factor (HIF)-1 is a master regulator whereby cells adapt to changes in oxygen concentrations. In addition to hypoxic conditions, non-hypoxic stimuli such as growth factors also activate expression of HIF-1. In this study, the mechanisms underlying low oxygen-dependent and epidermal growth factor (EGF)-dependent expression of HIF-1α were explored using porcine trophectoderm (pTr) cells. The results indicated that expression of HIF-1α and HIF-1β mRNAs was not affected by low concentrations of oxygen; however, hypoxic conditions markedly increased the abundance of HIF-1α protein, especially in nuclei of pTr cells. Even under normoxic conditions, the abundance of HIF-1α protein increased in response to EGF. This EGF-mediated increase in HIF-1α protein was blocked through inhibition of translation by cycloheximide. The inhibitors LY294002 (PI3K-AKT inhibitor), U0126 (inhibitor of ERK1/2) and rapamycin (mTOR inhibitor) also blocked the ability of EGF to increase HIF-1α protein and to phosphorylate AKT, ERK1/2 and mTOR proteins. Both hypoxia and EGF induced proliferation of pTr cells. This ability of EGF to stimulate proliferation of pTr cells was suppressed by EGFR siRNA, but not HIF-1α siRNA, but a significant decrease in EGF-induced HIF-1α protein occurred when pTr cells were transfected with HIF-1α siRNA. The results of the present study suggest that pTr cells adapt to oxygen deficiency and proliferate in response to an oxygen-dependent HIF-1 system, and that EGF at maternal–conceptus interface can increase the abundance of HIF-1α protein via translational regulation through AKT, ERK1/2 and mTOR signaling cascades. - Highlights: • HIF-1α expression is up-regulated in pTr cells under low oxygen concentrations. • EGF induces HIF-1α accumulation in pTr cells. • EGF-induced HIF-1α accumulation is blocked by de

  11. Hypoxia-inducible factor 1-mediated human GATA1 induction promotes erythroid differentiation under hypoxic conditions.

    Science.gov (United States)

    Zhang, Feng-Lin; Shen, Guo-Min; Liu, Xiao-Ling; Wang, Fang; Zhao, Ying-Ze; Zhang, Jun-Wu

    2012-08-01

    Hypoxia-inducible factor promotes erythropoiesis through coordinated cell type-specific hypoxia responses. GATA1 is essential to normal erythropoiesis and plays a crucial role in erythroid differentiation. In this study, we show that hypoxia-induced GATA1 expression is mediated by HIF1 in erythroid cells. Under hypoxic conditions, significantly increased GATA1 mRNA and protein levels were detected in K562 cells and erythroid induction cultures of CD34(+) haematopoietic stem/progenitor cells. Enforced HIF1α expression increased GATA1 expression, while HIF1α knockdown by RNA interference decreased GATA1 expression. In silico analysis revealed one potential hypoxia response element (HRE). The results from reporter gene and mutation analysis suggested that this element is necessary for hypoxic response. Chromatin immunoprecipitation (ChIP)-PCR showed that the putative HRE was recognized and bound by HIF1 in vivo. These results demonstrate that the up-regulation of GATA1 during hypoxia is directly mediated by HIF1.The mRNA expression of some erythroid differentiation markers was increased under hypoxic conditions, but decreased with RNA interference of HIF1α or GATA1. Flow cytometry analysis also indicated that hypoxia, desferrioxamine or CoCl(2) induced expression of erythroid surface markers CD71 and CD235a, while expression repression of HIF1α or GATA1 by RNA interference led to a decreased expression of CD235a. These results suggested that HIF1-mediated GATA1 up-regulation promotes erythropoiesis in order to satisfy the needs of an organism under hypoxic conditions. © 2011 The Authors Journal of Cellular and Molecular Medicine © 2011 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.

  12. The role of factor inhibiting HIF (FIH-1 in inhibiting HIF-1 transcriptional activity in glioblastoma multiforme.

    Directory of Open Access Journals (Sweden)

    Enfeng Wang

    Full Text Available Glioblastoma multiforme (GBM accounts for about 38% of primary brain tumors in the United States. GBM is characterized by extensive angiogenesis induced by vascular growth factors and cytokines. The transcription of these growth factors and cytokines is regulated by the Hypoxia-Inducible-Factor-1(HIF-1, which is a key regulator mediating the cellular response to hypoxia. It is known that Factor Inhibiting HIF-1, or FIH-1, is also involved in the cellular response to hypoxia and has the capability to physically interact with HIF-1 and block its transcriptional activity under normoxic conditions. Delineation of the regulatory role of FIH-1 will help us to better understand the molecular mechanism responsible for tumor growth and progression and may lead to the design of new therapies targeting cellular pathways in response to hypoxia. Previous studies have shown that the chromosomal region of 10q24 containing the FIH-1 gene is often deleted in GBM, suggesting a role for the FIH-1 in GBM tumorigenesis and progression. In the current study, we found that FIH-1 is able to inhibit HIF-mediated transcription of GLUT1 and VEGF-A, even under hypoxic conditions in human glioblastoma cells. FIH-1 has been found to be more potent in inhibiting HIF function than PTEN. This observation points to the possibility that deletion of 10q23-24 and loss or decreased expression of FIH-1 gene may lead to a constitutive activation of HIF-1 activity, an alteration of HIF-1 targets such as GLUT-1 and VEGF-A, and may contribute to the survival of cancer cells in hypoxia and the development of hypervascularization observed in GBM. Therefore FIH-1 can be potential therapeutic target for the treatment of GBM patients with poor prognosis.

  13. Radiation protective effect of hypoxia-inducible factor-1α (HIF-1α) on human oral squamous cell carcinoma cell lines

    International Nuclear Information System (INIS)

    Hosokawa, Y.; Okumura, K.; Terashima, S.; Sakakura, Y.

    2012-01-01

    We examined the effects of 5-Gy radiation on the expression of hypoxia-inducible factor-1α (HIF-1α) and the radiosensitivity of five human oral squamous cell carcinoma (OSCC) cell lines (SAS, Ca9-22, TT, BSC-OF and IS-FOM). In all of the cell lines, HIF-1α was expressed in mRNA, and radiation had no influence on gene transcription. The number of apoptotic cells increased 72 h after irradiation in cell lines SAS, Ca9-22 and TT cells, indicating low transcriptional levels of HIF-1α, and the levels of non-cleaved caspase-3, an executioner of apoptosis, and non-cleaved poly (adenosine diphosphate-ribose) polymerase (PARP), a marker of DNA damage early in apoptosis, decreased simultaneously. Conversely, radiation failed to induce apoptosis or to decrease expression of non-cleaved caspase-3 and PARP in cell-lines BSC-OF and IS-FOM cells that expressed high levels of HIF-1α. BSC-OF and IS-FOM cells exhibited high migratory capacity. When CoCl 2 was present in the medium, HIF-1α expression increased along with the survival of Ca9-22 cells after radiation exposure. These results suggest that OSCC cells expressing high levels of HIF-1α are resistant to radiation. HIF-1α can be used to control the short term radiosensitivity of cells. (authors)

  14. Hypoxia and hypoglycaemia in Ewing's sarcoma and osteosarcoma: regulation and phenotypic effects of Hypoxia-Inducible Factor

    International Nuclear Information System (INIS)

    Knowles, Helen J; Schaefer, Karl-Ludwig; Dirksen, Uta; Athanasou, Nicholas A

    2010-01-01

    Hypoxia regulates gene expression via the transcription factor HIF (Hypoxia-Inducible Factor). Little is known regarding HIF expression and function in primary bone sarcomas. We describe HIF expression and phenotypic effects of hypoxia, hypoglycaemia and HIF in Ewing's sarcoma and osteosarcoma. HIF-1α and HIF-2α immunohistochemistry was performed on a Ewing's tumour tissue array. Ewing's sarcoma and osteosarcoma cell lines were assessed for HIF pathway induction by Western blot, luciferase assay and ELISA. Effects of hypoxia, hypoglycaemia and isoform-specific HIF siRNA were assessed on proliferation, apoptosis and migration. 17/56 Ewing's tumours were HIF-1α-positive, 15 HIF-2α-positive and 10 positive for HIF-1α and HIF-2α. Expression of HIF-1α and cleaved caspase 3 localised to necrotic areas. Hypoxia induced HIF-1α and HIF-2α in Ewing's and osteosarcoma cell lines while hypoglycaemia specifically induced HIF-2α in Ewing's. Downstream transcription was HIF-1α-dependent in Ewing's sarcoma, but regulated by both isoforms in osteosarcoma. In both cell types hypoglycaemia reduced cellular proliferation by ≥ 45%, hypoxia increased apoptosis and HIF siRNA modulated hypoxic proliferation and migration. Co-localisation of HIF-1α and necrosis in Ewing's sarcoma suggests a role for hypoxia and/or hypoglycaemia in in vivo induction of HIF. In vitro data implicates hypoxia as the primary HIF stimulus in both Ewing's and osteosarcoma, driving effects on proliferation and apoptosis. These results provide a foundation from which to advance understanding of HIF function in the pathobiology of primary bone sarcomas

  15. Sphingosine-1-Phosphate as a Regulator of Hypoxia-Induced Factor-1α in Thyroid Follicular Carcinoma Cells

    Science.gov (United States)

    Asghar, Muhammad Yasir; Bergelin, Nina; Jaakkola, Panu; Törnquist, Kid

    2013-01-01

    Sphingosine-1-phosphate (S1P) is a bioactive lipid, which regulates several cancer-related processes including migration and angiogenesis. We have previously shown S1P to induce migration of follicular ML-1 thyroid cancer cells. Hypoxia-induced factor-1 (HIF-1) is an oxygen-sensitive transcription factor, which adapts cells to hypoxic conditions through increased survival, motility and angiogenesis. Due to these properties and its increased expression in response to intratumoral hypoxia, HIF-1 is considered a significant regulator of tumor biology. We found S1P to increase expression of the regulatory HIF-1α subunit in normoxic ML-1 cells. S1P also increased HIF-1 activity and expression of HIF-1 target genes. Importantly, inhibition or knockdown of HIF-1α attenuated the S1P-induced migration of ML-1 cells. S1P-induced HIF-1α expression was mediated by S1P receptor 3 (S1P3), Gi proteins and their downstream effectors MEK, PI3K, mTOR and PKCβI. Half-life measurements with cycloheximide indicated that S1P treatment stabilized the HIF-1α protein. On the other hand, S1P activated translational regulators eIF-4E and p70S6K, which are known to control HIF-1α synthesis. In conclusion, we have identified S1P as a non-hypoxic regulator of HIF-1 activity in thyroid cancer cells, studied the signaling involved in S1P-induced HIF-1α expression and shown S1P-induced migration to be mediated by HIF-1. PMID:23824493

  16. Sphingosine-1-Phosphate as a Regulator of Hypoxia-Induced Factor-1α in Thyroid Follicular Carcinoma Cells.

    Directory of Open Access Journals (Sweden)

    Veronica Kalhori

    Full Text Available Sphingosine-1-phosphate (S1P is a bioactive lipid, which regulates several cancer-related processes including migration and angiogenesis. We have previously shown S1P to induce migration of follicular ML-1 thyroid cancer cells. Hypoxia-induced factor-1 (HIF-1 is an oxygen-sensitive transcription factor, which adapts cells to hypoxic conditions through increased survival, motility and angiogenesis. Due to these properties and its increased expression in response to intratumoral hypoxia, HIF-1 is considered a significant regulator of tumor biology. We found S1P to increase expression of the regulatory HIF-1α subunit in normoxic ML-1 cells. S1P also increased HIF-1 activity and expression of HIF-1 target genes. Importantly, inhibition or knockdown of HIF-1α attenuated the S1P-induced migration of ML-1 cells. S1P-induced HIF-1α expression was mediated by S1P receptor 3 (S1P3, Gi proteins and their downstream effectors MEK, PI3K, mTOR and PKCβI. Half-life measurements with cycloheximide indicated that S1P treatment stabilized the HIF-1α protein. On the other hand, S1P activated translational regulators eIF-4E and p70S6K, which are known to control HIF-1α synthesis. In conclusion, we have identified S1P as a non-hypoxic regulator of HIF-1 activity in thyroid cancer cells, studied the signaling involved in S1P-induced HIF-1α expression and shown S1P-induced migration to be mediated by HIF-1.

  17. Andrographolide inhibits hypoxia-induced HIF-1α-driven endothelin 1 secretion by activating Nrf2/HO-1 and promoting the expression of prolyl hydroxylases 2/3 in human endothelial cells.

    Science.gov (United States)

    Lin, Hung-Chih; Su, Shih-Li; Lu, Chia-Yang; Lin, Ai-Hsuan; Lin, Wan-Chun; Liu, Chin-San; Yang, Ya-Chen; Wang, Hsiu-Miao; Lii, Chong-Kuei; Chen, Haw-Wen

    2017-03-01

    Andrographolide, the main bioactive component of the medicinal plant Andrographis paniculata, has been shown to possess potent anti-inflammatory activity. Endothelin 1 (ET-1), a potent vasoconstrictor peptide produced by vascular endothelial cells, displays proinflammatory property. Hypoxia-inducible factor 1α (HIF-1α), the regulatory member of the transcription factor heterodimer HIF-1α/β, is one of the most important molecules that responds to hypoxia. Changes in cellular HIF-1α protein level are the result of altered gene transcription and protein stability, with the latter being dependent on prolyl hydroxylases (PHDs). In this study, inhibition of pro-inflammatory ET-1 expression and changes of HIF-1α gene transcription and protein stability under hypoxia by andrographolide in EA.hy926 endothelial-like cells were investigated. Hypoxic conditions were created using the hypoxia-mimetic agent CoCl 2. We found that hypoxia stimulated the production of reactive oxygen species (ROS), the expression of HIF-1α mRNA and protein, and the expression and secretion of ET-1. These effects, however, were attenuated by co-exposure to andrographolide, bilirubin, and RuCO. Silencing Nrf2 and heme oxygenase 1 (HO-1) reversed the inhibitory effects of andrographolide on hypxoia-induced HIF-1α mRNA and protein expression. Moreover, andrographolide increased the expression of prolyl hydroxylases (PHD) 2/3, which hydroxylate HIF-1α and promotes HIF-1α proteasome degradation, with an increase in HIF-1α hydroxylation was noted under hypoxia. Inhibition of p38 MAPK abrogated the hypoxia-induced increases in HIF-1α mRNA and protein expression as well as ET-1 mRNA expression and secretion. Taken together, these results suggest that andrographolide suppresses hypoxia-induced pro-inflammatory ET-1 expression by activating Nrf2/HO-1, inhibiting p38 MAPK signaling, and promoting PHD2/3 expression. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 918-930, 2017. © 2016 Wiley

  18. Zeaxanthin Inhibits Hypoxia-Induced VEGF Secretion by RPE Cells through Decreased Protein Levels of Hypoxia-Inducible Factors-1α

    Directory of Open Access Journals (Sweden)

    Richard Rosen

    2015-01-01

    Full Text Available Hypoxia is the most important stimulus leading to upregulation of VEGF in the retina and this is caused by accumulation of hypoxia-inducible factors-1α (HIF-1α protein. The effects of zeaxanthin, a natural phytochemical, on the VEGF and HIF-1α expression in the primary culture of human retinal pigment epithelial (RPE cells were studied. An in vitro RPE cell hypoxia model was established by placing cells under 1% oxygen pressure or by adding cobalt chloride (CoCl2 to the culture medium. RPE cells and conditioned media were collected from cultures treated with and without zeaxanthin under normoxic and hypoxic conditions. VEGF and HIF-1α protein and RNA levels were measured by ELISA kits and RT-PCR, respectively. Hypoxia caused a significant increase of VEGF expression and accumulation of HIF-1α in RPE cells. Zeaxanthin at 50–150 μM significantly inhibited the expression of VEGF and accumulation of HIF-1α protein caused by hypoxia but did not affect expression of VEGF and HIF-1α under normoxic conditions. This is the first report on the effect of zeaxanthin on VEGF and HIF-1α levels in cultured RPE cells and suggests that zeaxanthin may have potential value in the prevention and treatment of various retinal diseases associated with vascular leakage and neovascularization.

  19. Potent inhibition of tumoral hypoxia-inducible factor 1α by albendazole

    International Nuclear Information System (INIS)

    Pourgholami, Mohammad H; Cai, Zhao Y; Badar, Samina; Wangoo, Kiran; Poruchynsky, Marianne S; Morris, David L

    2010-01-01

    Emerging reports suggest resistance, increased tumor invasiveness and metastasis arising from treatment with drugs targeting vascular endothelial growth factor (VEGF). It is believed that increased tumoral hypoxia plays a prominent role in the development of these phenomena. Inhibition of tumoral hypoxia inducible factor (HIF-1α) is thus becoming an increasingly attractive therapeutic target in the treatment of cancer. We hypothesized that the anti-VEGF effect of albendazole (ABZ) could be mediated through inhibition of tumoral HIF-1α. In vitro, the effects of ABZ on HIF-1α levels in human ovarian cancer cells (OVCAR-3) were investigated using hypoxic chamber or desferrioxamine (DFO) induced-hypoxia. In vivo, the effects of ABZ (150 mg/kg, i.p., single dose) on the tumor levels of HIF-1α and VEGF protein and mRNA were investigated by western blotting, RT-PCR and real time-PCR. In vitro, ABZ inhibited cellular HIF-1α protein accumulation resulting from placement of cells under hypoxic chamber or exposure to DFO. In vivo, tumors excised from vehicle treated mice showed high levels of both HIF-1α and VEGF. Whereas, tumoral HIF-1α and VEGF protein levels were highly suppressed in ABZ treated mice. Tumoral VEGFmRNA (but not HIF-1αmRNA) was also found to be highly suppressed by ABZ. These results demonstrate for the first time the effects of an acute dose of ABZ in profoundly suppressing both HIF-1α and VEGF within the tumor. This dual inhibition may provide additional value in inhibiting angiogenesis and be at least partially effective in inhibiting tumoral HIF-1α surge, tumor invasiveness and metastasis

  20. Retinal neuroprotection by hypoxic preconditioning is independent of hypoxia-inducible factor-1 alpha expression in photoreceptors.

    Science.gov (United States)

    Thiersch, Markus; Lange, Christina; Joly, Sandrine; Heynen, Severin; Le, Yun Zheng; Samardzija, Marijana; Grimm, Christian

    2009-06-01

    Hypoxic preconditioning stabilizes hypoxia-inducible factor (HIF) 1 alpha in the retina and protects photoreceptors against light-induced cell death. HIF-1 alpha is one of the major transcription factors responding to low oxygen tension and can differentially regulate a large number of target genes. To analyse whether photoreceptor-specific expression of HIF-1 alpha is essential to protect photoreceptors by hypoxic preconditioning, we knocked down expression of HIF-1 alpha specifically in photoreceptor cells, using the cyclization recombinase (Cre)-lox system. The Cre-mediated knockdown caused a 20-fold reduced expression of Hif-1 alpha in the photoreceptor cell layer. In the total retina, RNA expression was reduced by 65%, and hypoxic preconditioning led to only a small increase in HIF-1 alpha protein levels. Accordingly, HIF-1 target gene expression after hypoxia was significantly diminished. Retinas of Hif-1 alpha knockdown animals did not show any pathological alterations, and tolerated hypoxic exposure in a comparable way to wild-type retinas. Importantly, the strong neuroprotective effect of hypoxic preconditioning against light-induced photoreceptor degeneration persisted in knockdown mice, suggesting that hypoxia-mediated survival of light exposure does not depend on an autocrine action of HIF-1 alpha in photoreceptor cells. Hypoxia-mediated stabilization of HIF-2 alpha and phosphorylation of signal transducer and activator of transcription 3 (STAT 3) were not affected in the retinas of Hif-1 alpha knockdown mice. Thus, these factors are candidates for regulating the resistance of photoreceptors to light damage after hypoxic preconditioning, along with several potentially neuroprotective genes that were similarly induced in hypoxic knockdown and control mice.

  1. Erythropoietin inhibits HIF-1α expression via upregulation of PHD-2 transcription and translation in an in-vitro model of hypoxia ischemia

    Science.gov (United States)

    Souvenir, Rhonda; Flores, Jerry J.; Ostrowski, Robert P.; Manaenko, Anatol; Duris, Kamil; Tang, Jiping

    2014-01-01

    Hypoxia inducible factor (HIF)-1α is the central transcriptional factor for the regulation of oxygen-associated genes in response to hypoxia. Erythropoietin (EPO), a hematopoietic growth factor, increases oxygen availability during hypoxia/ischemia and is associated with neuroprotection following hypoxia ischemia in laboratory models of stroke. However, EPO has failed to translate in a clinical setting. Thus it is critical to elucidate the key players in EPO-induced neuroprotection. Our preliminary studies have shown that EPO, as a downstream gene of hypoxia inducible factor (HIF), inhibits HIF-1α in a dose-dependent manner in an in-vitro model of hypoxia ischemia. This study is designed to elucidate the primary mediator of EPO-induced HIF-1α inhibition and subsequent cell survival/neuroprotection. Oxygen and glucose deprivation (OGD) of nerve growth factor (NGF) differentiated rat pheochromocytoma (PC-12) cells were used to model hypoxia ischemia in an in vitro environment. The profile of HIF-1α, HIF-2α and PHD-2 expression, HIF-1α and prolyl hydroxylase (PHD-2) mRNA levels, MMP-9 and cell death was evaluated in the presence and absence of either EPO or PHD-2 inhibitor during OGD. Our findings showed that EPO treatment resulted in an increase in PHD-2 transcription and translation, inhibition of HIF-1α expression, reactive oxygen species (ROS) formation and matrix metalloproteinase (MMP)-9 activity, resulting in increased cell survival after OGD. We also observed that EPO-induced cell survival/neuroprotection was reversed by siRNA silencing of PHD-2. This led to the conclusion that PHD-2 is a key mediator of EPO-induced HIF-1α inhibition and subsequent neuroprotection in an in vitro model of hypoxia ischemia. PMID:24323731

  2. Glycogen synthesis is induced in hypoxia by the hypoxia-inducible factor and promotes cancer cell survival

    Directory of Open Access Journals (Sweden)

    Joffrey ePelletier

    2012-02-01

    Full Text Available The hypoxia-inducible factor 1 (HIF-1, in addition to genetic and epigenetic changes, is largely responsible for alterations in cell metabolism in hypoxic tumor cells. This transcription factor not only favors cell proliferation through the metabolic shift from oxidative phosphorylation to glycolysis and lactic acid production but also stimulates nutrient supply by mediating adaptive survival mechanisms. In this study we showed that glycogen synthesis is enhanced in non-cancer and cancer cells when exposed to hypoxia, resulting in a large increase in glycogen stores. Furthermore, we demonstrated that the mRNA and protein levels of the first enzyme of glycogenesis, phosphoglucomutase1 (PGM1, were increased in hypoxia. We showed that induction of glycogen storage as well as PGM1 expression were dependent on HIF-1 and HIF-2. We established that hypoxia-induced glycogen stores are rapidly mobilized in cells that are starved of glucose. Glycogenolysis allows these hypoxia-preconditioned cells to confront and survive glucose deprivation. In contrast normoxic control cells exhibit a high rate of cell death following glucose removal. These findings point to the important role of hypoxia and HIF in inducing mechanisms of rapid adaptation and survival in response to a decrease in oxygen tension. We propose that a decrease in pO2 acts as an alarm that prepares the cells to face subsequent nutrient depletion and to survive.

  3. Glycogen Synthesis is Induced in Hypoxia by the Hypoxia-Inducible Factor and Promotes Cancer Cell Survival

    Energy Technology Data Exchange (ETDEWEB)

    Pelletier, Joffrey; Bellot, Grégory [Institute of Developmental Biology and Cancer Research, CNRS-UMR 6543, Centre Antoine Lacassagne, University of Nice-Sophia Antipolis, Nice (France); Gounon, Pierre; Lacas-Gervais, Sandra [Centre Commun de Microscopie Appliquée, University of Nice-Sophia Antipolis, Nice (France); Pouysségur, Jacques; Mazure, Nathalie M., E-mail: mazure@unice.fr [Institute of Developmental Biology and Cancer Research, CNRS-UMR 6543, Centre Antoine Lacassagne, University of Nice-Sophia Antipolis, Nice (France)

    2012-02-28

    The hypoxia-inducible factor 1 (HIF-1), in addition to genetic and epigenetic changes, is largely responsible for alterations in cell metabolism in hypoxic tumor cells. This transcription factor not only favors cell proliferation through the metabolic shift from oxidative phosphorylation to glycolysis and lactic acid production but also stimulates nutrient supply by mediating adaptive survival mechanisms. In this study we showed that glycogen synthesis is enhanced in non-cancer and cancer cells when exposed to hypoxia, resulting in a large increase in glycogen stores. Furthermore, we demonstrated that the mRNA and protein levels of the first enzyme of glycogenesis, phosphoglucomutase1 (PGM1), were increased in hypoxia. We showed that induction of glycogen storage as well as PGM1 expression were dependent on HIF-1 and HIF-2. We established that hypoxia-induced glycogen stores are rapidly mobilized in cells that are starved of glucose. Glycogenolysis allows these “hypoxia-preconditioned” cells to confront and survive glucose deprivation. In contrast normoxic control cells exhibit a high rate of cell death following glucose removal. These findings point to the important role of hypoxia and HIF in inducing mechanisms of rapid adaptation and survival in response to a decrease in oxygen tension. We propose that a decrease in pO{sub 2} acts as an “alarm” that prepares the cells to face subsequent nutrient depletion and to survive.

  4. Glycogen Synthesis is Induced in Hypoxia by the Hypoxia-Inducible Factor and Promotes Cancer Cell Survival

    International Nuclear Information System (INIS)

    Pelletier, Joffrey; Bellot, Grégory; Gounon, Pierre; Lacas-Gervais, Sandra; Pouysségur, Jacques; Mazure, Nathalie M.

    2012-01-01

    The hypoxia-inducible factor 1 (HIF-1), in addition to genetic and epigenetic changes, is largely responsible for alterations in cell metabolism in hypoxic tumor cells. This transcription factor not only favors cell proliferation through the metabolic shift from oxidative phosphorylation to glycolysis and lactic acid production but also stimulates nutrient supply by mediating adaptive survival mechanisms. In this study we showed that glycogen synthesis is enhanced in non-cancer and cancer cells when exposed to hypoxia, resulting in a large increase in glycogen stores. Furthermore, we demonstrated that the mRNA and protein levels of the first enzyme of glycogenesis, phosphoglucomutase1 (PGM1), were increased in hypoxia. We showed that induction of glycogen storage as well as PGM1 expression were dependent on HIF-1 and HIF-2. We established that hypoxia-induced glycogen stores are rapidly mobilized in cells that are starved of glucose. Glycogenolysis allows these “hypoxia-preconditioned” cells to confront and survive glucose deprivation. In contrast normoxic control cells exhibit a high rate of cell death following glucose removal. These findings point to the important role of hypoxia and HIF in inducing mechanisms of rapid adaptation and survival in response to a decrease in oxygen tension. We propose that a decrease in pO 2 acts as an “alarm” that prepares the cells to face subsequent nutrient depletion and to survive.

  5. Hypoxia inducible factor-1 (HIF-1)–flavin containing monooxygenase-2 (FMO-2) signaling acts in silver nanoparticles and silver ion toxicity in the nematode, Caenorhabditis elegans

    International Nuclear Information System (INIS)

    Eom, Hyun-Jeong; Ahn, Jeong-Min; Kim, Younghun; Choi, Jinhee

    2013-01-01

    In the present study, nanotoxicity mechanism associated with silver nanoparticles (AgNPs) exposure was investigated on the nematode, Caenorhabditis elegans focusing on the hypoxia response pathway. In order to test whether AgNPs-induced hypoxia inducible factor-1 (HIF-1) activation was due to hypoxia or to oxidative stress, depletion of dissolved oxygen (DO) in the test media and a rescue effect using an antioxidant were investigated, respectively. The results suggested that oxidative stress was involved in activation of the HIF-1 pathway. We then investigated the toxicological implications of HIF-1 activation by examining the HIF-1 mediated transcriptional response. Of the genes tested, increased expression of the flavin containing monooxygenase-2 (FMO-2) gene was found to be the most significant as induced by AgNPs exposure. We found that AgNPs exposure induced FMO-2 activation in a HIF-1 and p38 MAPK PMK-1 dependent manner, and oxidative stress was involved in it. We conducted all experiments to include comparison of AgNPs and AgNO 3 in order to evaluate whether any observed toxicity was due to dissolution or particle specific. The AgNPs and AgNO 3 did not produce any qualitative differences in terms of exerting toxicity in the pathways observed in this study, however, considering equal amount of silver mass, in every endpoint tested the AgNPs were found to be more toxic than AgNO 3 . These results suggest that Ag nanotoxicity is dependent not only on dissolution of Ag ion but also on particle specific effects and HIF-1–FMO-2 pathway seems to be involved in it. - Highlights: • HIF-1 signaling was investigated in C. elegans exposed to AgNPs and AgNO 3 . • HIF-1 and PMK-1 were needed for AgNPs- and AgNO 3 -induced fmo-2 gene expression. • PMK-1HIF-1–FMO-2 pathway was dependent on oxidative stress. • AgNPs and AgNO 3 did not produce any qualitative differences in HIF-1 signaling. • AgNPs were more toxic than an equal amount of silver mass contained

  6. Hypoxia inducible factor-1 (HIF-1)–flavin containing monooxygenase-2 (FMO-2) signaling acts in silver nanoparticles and silver ion toxicity in the nematode, Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Eom, Hyun-Jeong; Ahn, Jeong-Min [School of Environmental Engineering and Graduate School of Energy and Environmental System Engineering, University of Seoul, 90 Jeonnong-dong, Dongdaemun-gu, Seoul 130-743 (Korea, Republic of); Kim, Younghun [Department of Chemical Engineering, Kwangwoon University, 447-1, Wolgye-dong, Nowon-gu, Seoul 139-701 (Korea, Republic of); Choi, Jinhee, E-mail: jinhchoi@uos.ac.kr [School of Environmental Engineering and Graduate School of Energy and Environmental System Engineering, University of Seoul, 90 Jeonnong-dong, Dongdaemun-gu, Seoul 130-743 (Korea, Republic of)

    2013-07-15

    In the present study, nanotoxicity mechanism associated with silver nanoparticles (AgNPs) exposure was investigated on the nematode, Caenorhabditis elegans focusing on the hypoxia response pathway. In order to test whether AgNPs-induced hypoxia inducible factor-1 (HIF-1) activation was due to hypoxia or to oxidative stress, depletion of dissolved oxygen (DO) in the test media and a rescue effect using an antioxidant were investigated, respectively. The results suggested that oxidative stress was involved in activation of the HIF-1 pathway. We then investigated the toxicological implications of HIF-1 activation by examining the HIF-1 mediated transcriptional response. Of the genes tested, increased expression of the flavin containing monooxygenase-2 (FMO-2) gene was found to be the most significant as induced by AgNPs exposure. We found that AgNPs exposure induced FMO-2 activation in a HIF-1 and p38 MAPK PMK-1 dependent manner, and oxidative stress was involved in it. We conducted all experiments to include comparison of AgNPs and AgNO{sub 3} in order to evaluate whether any observed toxicity was due to dissolution or particle specific. The AgNPs and AgNO{sub 3} did not produce any qualitative differences in terms of exerting toxicity in the pathways observed in this study, however, considering equal amount of silver mass, in every endpoint tested the AgNPs were found to be more toxic than AgNO{sub 3}. These results suggest that Ag nanotoxicity is dependent not only on dissolution of Ag ion but also on particle specific effects and HIF-1–FMO-2 pathway seems to be involved in it. - Highlights: • HIF-1 signaling was investigated in C. elegans exposed to AgNPs and AgNO{sub 3}. • HIF-1 and PMK-1 were needed for AgNPs- and AgNO{sub 3}-induced fmo-2 gene expression. • PMK-1HIF-1–FMO-2 pathway was dependent on oxidative stress. • AgNPs and AgNO{sub 3} did not produce any qualitative differences in HIF-1 signaling. • AgNPs were more toxic than an equal

  7. Hypoxia-inducible factor 1 alpha is a poor prognostic factor and potential therapeutic target in malignant peripheral nerve sheath tumor.

    Directory of Open Access Journals (Sweden)

    Suguru Fukushima

    Full Text Available Malignant peripheral nerve sheath tumor (MPNST is a rare soft tissue sarcoma with poor prognosis. Hypoxia-inducible factor 1 (HIF-1 plays a crucial role in the cellular response to hypoxia and regulates the expression of multiple genes involved in tumor progression in various cancers. However, the importance of the expression of HIF-1α in MPNSTs is unclear.The expression of HIF-1α was examined immunohistochemically in 82 MPNST specimens. Cell culture assays of human MPNST cells under normoxic and hypoxic conditions were used to evaluate the impact of anti-HIF-1α-specific siRNA inhibition on cell survival. A screening kit was employed to identify small molecules that inhibited HIF-1α.The nuclear expression of HIF-1α was positive in 75.6% of MPNST samples (62/82 cases. Positivity for HIF-1α was a significant poor prognostic factor both in univariate (P = 0.048 and multivariate (P ≤ 0.0001 analyses. HIF-1α knockdown abrogated MPNST cell growth, inducing apoptosis. Finally, chetomin, an inhibitor of HIF-1α, effectively inhibited the growth of MPNST cells and induced their apoptosis.Inhibition of HIF-1α signaling is a potential treatment option for MPNSTs.

  8. Specific inhibition of hypoxia-inducible factor (HIF)-1 alpha activation and of vascular endothelial growth factor (VEGF) production by flavonoids.

    Science.gov (United States)

    Hasebe, Yuki; Egawa, Kiyoshi; Yamazaki, Yoko; Kunimoto, Setsuko; Hirai, Yasuaki; Ida, Yoshiteru; Nose, Kiyoshi

    2003-10-01

    Screening using a reporter under the control of the hypoxia-response element (HRE) identified several flavonoids and homoisoflavonoids that inhibit the activation of HRE under hypoxic conditions. Among various compounds, isorhamnetin, luteolin, quercetin, and methyl ophiopogonanone B (MOB) were effective at 3 to 9 microg/ml in inhibiting the reporter activity. The expression of vascular endothelial growth factor (VEGF) mRNA during hypoxia was also inhibited by MOB in HepG2 cells, but the effective doses were 10 to 20 microg/ml. MOB caused destabilization of hypoxia-inducible factor (HIF)-1alpha, as revealed by Western blotting, that was dependent on proteasome activity and the tumor suppressor, p53. The tubular formation and migration of human umbilical vein endothelial cells was also inhibited by MOB. MOB is expected to act as an inhibitor of angiogenesis.

  9. Molecular basis for the regulation of hypoxia-inducible factor-1α levels by 2-deoxy-D-ribose.

    Science.gov (United States)

    Ikeda, Ryuji; Tabata, Sho; Tajitsu, Yusuke; Nishizawa, Yukihiko; Minami, Kentaro; Furukawa, Tatsuhiko; Yamamoto, Masatatsu; Shinsato, Yoshinari; Akiyama, Shin-Ichi; Yamada, Katsushi; Takeda, Yasuo

    2013-09-01

    The angiogenic factor, platelet-derived endothelial cell growth factor/thymidine phosphorylase (PD-ECGF/TP), stimulates the chemotaxis of endothelial cells and confers resistance to apoptosis induced by hypoxia. 2-Deoxy-D-ribose, a degradation product of thymidine generated by TP enzymatic activity, inhibits the upregulation of hypoxia-inducible factor (HIF) 1α, BNIP3 and caspase-3 induced by hypoxia. In the present study, we investigated the molecular basis for the suppressive effect of 2-deoxy-D-ribose on the upregulation of HIF-1α. 2-Deoxy-D-ribose enhanced the interaction of HIF-1α and the von Hippel-Lindau (VHL) protein under hypoxic conditions. It did not affect the expression of HIF-1α, prolyl hydroxylase (PHD)1/2/3 and VHL mRNA under normoxic or hypoxic conditions, but enhanced the interaction of HIF-1α and PHD2 under hypoxic conditions. 2-Deoxy-D-ribose also increased the amount of hydroxy-HIF-1α in the presence of the proteasome inhibitor MG-132. The expression levels of TP are elevated in many types of malignant solid tumors and, thus, 2-deoxy-D-ribose generated by TP in these tumors may play an important role in tumor progression by preventing hypoxia-induced apoptosis.

  10. Hypoxia and hypoxia mimetics decrease aquaporin 5 (AQP5 expression through both hypoxia inducible factor-1α and proteasome-mediated pathways.

    Directory of Open Access Journals (Sweden)

    Jitesh D Kawedia

    Full Text Available The alveolar epithelium plays a central role in gas exchange and fluid transport, and is therefore critical for normal lung function. Since the bulk of water flux across this epithelium depends on the membrane water channel Aquaporin 5 (AQP5, we asked whether hypoxia had any effect on AQP5 expression. We show that hypoxia causes a significant (70% decrease in AQP5 expression in the lungs of mice exposed to hypoxia. Hypoxia and the hypoxia mimetic, cobalt, also caused similar decreases in AQP5 mRNA and protein expression in the mouse lung epithelial cell line MLE-12. The action of hypoxia and cobalt on AQP5 transcription was demonstrated by directly quantifying heternonuclear RNA by real-time PCR. Dominant negative mutants of Hypoxia Inducible Factor (HIF-1α and HIF-1α siRNA blocked the action of cobalt, showing that HIF-1α is a key component in this mechanism. The proteasome inhibitors, lactacystin or proteasome inhibitor-III completely abolished the effect of hypoxia and cobalt both at the protein and mRNA level indicating that the proteasome pathway is probably involved not only for the stability of HIF-1α protein, but for the stability of unidentified transcription factors that regulate AQP5 transcription. These studies reveal a potentially important physiological mechanism linking hypoxic stress and membrane water channels.

  11. Hypoxia and Hypoxia Mimetics Decrease Aquaporin 5 (AQP5) Expression through Both Hypoxia Inducible Factor-1α and Proteasome-Mediated Pathways

    Science.gov (United States)

    Kawedia, Jitesh D.; Yang, Fan; Sartor, Maureen A.; Gozal, David; Czyzyk-Krzeska, Maria; Menon, Anil G.

    2013-01-01

    The alveolar epithelium plays a central role in gas exchange and fluid transport, and is therefore critical for normal lung function. Since the bulk of water flux across this epithelium depends on the membrane water channel Aquaporin 5 (AQP5), we asked whether hypoxia had any effect on AQP5 expression. We show that hypoxia causes a significant (70%) decrease in AQP5 expression in the lungs of mice exposed to hypoxia. Hypoxia and the hypoxia mimetic, cobalt, also caused similar decreases in AQP5 mRNA and protein expression in the mouse lung epithelial cell line MLE-12. The action of hypoxia and cobalt on AQP5 transcription was demonstrated by directly quantifying heternonuclear RNA by real-time PCR. Dominant negative mutants of Hypoxia Inducible Factor (HIF-1α) and HIF-1α siRNA blocked the action of cobalt, showing that HIF-1α is a key component in this mechanism. The proteasome inhibitors, lactacystin or proteasome inhibitor-III completely abolished the effect of hypoxia and cobalt both at the protein and mRNA level indicating that the proteasome pathway is probably involved not only for the stability of HIF-1α protein, but for the stability of unidentified transcription factors that regulate AQP5 transcription. These studies reveal a potentially important physiological mechanism linking hypoxic stress and membrane water channels. PMID:23469202

  12. Furan- and Thiophene-2-Carbonyl Amino Acid Derivatives Activate Hypoxia-Inducible Factor via Inhibition of Factor Inhibiting Hypoxia-Inducible Factor-1

    Directory of Open Access Journals (Sweden)

    Shin-ichi Kawaguchi

    2018-04-01

    Full Text Available Induction of a series of anti-hypoxic proteins protects cells during exposure to hypoxic conditions. Hypoxia-inducible factor-α (HIF-α is a major transcription factor that orchestrates this protective effect. To activate HIF exogenously, without exposing cells to hypoxic conditions, many small-molecule inhibitors targeting prolyl hydroxylase domain-containing protein have been developed. In addition, suppression of factor inhibiting HIF-1 (FIH-1 has also been shown to have the potential to activate HIF-α. However, few small-molecule inhibitors of FIH-1 have been developed. In this study, we synthesized a series of furan- and thiophene-2-carbonyl amino acid derivatives having the potential to inhibit FIH-1. The inhibitory activities of these compounds were evaluated in SK-N-BE(2c cells by measuring HIF response element (HRE promoter activity. Several furan- and thiophene-2-carbonyl amino acid derivatives inhibited FIH-1 based on correlations among the docking score of the FIH-1 active site, the chemical structure of the compounds, and biological HIF-α/HRE transcriptional activity.

  13. Cancer cell-associated cytoplasmic B7–H4 is induced by hypoxia through hypoxia-inducible factor-1α and promotes cancer cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, You-Kyoung [Department of Microbiology and Immunology, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Advanced Research Center for Multiple Myeloma, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Park, Sae-Gwang; Choi, Il-Whan [Department of Microbiology and Immunology, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Lee, Soo-Woong [Advanced Research Center for Multiple Myeloma, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Lee, Sang Min [Department of Internal Medicine, Division of Hematology/Oncology, Busan Paik Hospital, Inje University, Busan 614-735 (Korea, Republic of); Choi, Inhak, E-mail: miccih@inje.ac.kr [Department of Microbiology and Immunology, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Advanced Research Center for Multiple Myeloma, Inje University College of Medicine, Busan 614-735 (Korea, Republic of)

    2015-04-03

    Aberrant B7–H4 expression in cancer tissues serves as a novel prognostic biomarker for poor survival in patients with cancer. However, the factor(s) that induce cancer cell-associated B7–H4 remain to be fully elucidated. We herein demonstrate that hypoxia upregulates B7–H4 transcription in primary CD138{sup +} multiple myeloma cells and cancer cell lines. In support of this finding, analysis of the Multiple Myeloma Genomics Portal (MMGP) data set revealed a positive correlation between the mRNA expression levels of B7–H4 and the endogenous hypoxia marker carbonic anhydrogenase 9. Hypoxia-induced B7–H4 expression was detected in the cytoplasm, but not in cancer cell membranes. Chromatin immunoprecipitation analysis demonstrated binding of hypoxia-inducible factor-1α (HIF-1α) to proximal hypoxia-response element (HRE) sites within the B7–H4 promoter. Knockdown of HIF-1α and pharmacological inhibition of HIF-1α diminished B7–H4 expression. Furthermore, knockdown of cytoplasmic B7–H4 in MCF-7 decreased the S-phase cell population under hypoxia. Finally, MMGP analysis revealed a positive correlation between the transcript levels of B7–H4 and proliferation-related genes including MKI67, CCNA1, and Myc in several patients with multiple myeloma. Our results provide insight into the mechanisms underlying B7–H4 upregulation and its role in cancer cell proliferation in a hypoxic tumor microenvironment. - Highlights: • Hypoxia upregulates B7–H4 transcription and protein expression. • Hypoxia-induced B7–H4 is detected in the cytoplasm, but not on membrane. • ChIP assay reveals a binding of HIF-1α to B7–H4 promoter at HRE site. • Knockdown and pharmacological inhibition of HIF-1α reduce B7–H4 expression. • B7–H4 knockdown decrease the number of cells in S-phase of cell cycle.

  14. Interaction between hypoxia, AKT and HIF-1 signaling in HNSCC and NSCLC: implications for future treatment strategies

    NARCIS (Netherlands)

    Stegeman, H.; Span, P.N.; Peeters, W.J.M.; Verheijen, M.M.; Grenman, R.; Meijer, T.W.H.; Kaanders, J.H.A.M.; Bussink, J.

    2016-01-01

    BACKGROUND: Hypoxia is a negative prognostic factor and this study investigated the relationship between hypoxia, hypoxia inducible factor 1 (HIF-1) and AKT signaling in head and neck squamous cell carcinoma (HNSCC) and non-small-cell lung cancer (NSCLC). RESULTS/METHODOLOGY: pAKT was induced by

  15. IBMX protects human proximal tubular epithelial cells from hypoxic stress through suppressing hypoxia-inducible factor-1α expression.

    Science.gov (United States)

    Hasan, Arif Ul; Kittikulsuth, Wararat; Yamaguchi, Fuminori; Musarrat Ansary, Tuba; Rahman, Asadur; Shibayama, Yuki; Nakano, Daisuke; Hitomi, Hirofumi; Tokuda, Masaaki; Nishiyama, Akira

    2017-09-15

    Hypoxia predisposes renal fibrosis. This study was conducted to identify novel approaches to ameliorate the pathogenic effect of hypoxia. Using human proximal tubular epithelial cells we showed that a pan-phosphodiesterase (PDE) inhibitor, 3-isobutyl-1-methylxanthine (IBMX) dose and time dependently downregulated hypoxia-inducible factor 1α (HIF-1α) mRNA expression, which was further augmented by addition of a transcriptional inhibitor, actinomycin D. IBMX also increased the cellular cyclic adenosine monophosphate (cAMP) level. Luciferase assay showed that blocking of protein kinase A (PKA) using H89 reduced, while 8-Br-cAMP agonized the repression of HIF-1α promoter activity in hypoxic condition. Deletion of cAMP response element binding sites from the HIF-1α promoter abrogated the effect of IBMX. Western blot and immunofluorescent study confirmed that the CoCl 2 induced increased HIF-1α protein in whole cell lysate and in nucleus was reduced by the IBMX. Through this process, IBMX attenuated both CoCl 2 and hypoxia induced mRNA expressions of two pro-fibrogenic factors, platelet-derived growth factor B and lysyl oxidase. Moreover, IBMX reduced production of a mesenchymal transformation factor, β-catenin; as well as protected against hypoxia induced cell-death. Taken together, our study showed novel evidence that the PDE inhibitor IBMX can downregulate the transcription of HIF-1α, and thus may attenuate hypoxia induced renal fibrosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Down-regulation of hypoxia-inducible factor-1 alpha and vascular endothelial growth factor by HEXIM1 attenuates myocardial angiogenesis in hypoxic mice.

    Science.gov (United States)

    Yoshikawa, Noritada; Shimizu, Noriaki; Ojima, Hidenori; Kobayashi, Hiroshi; Hosono, Osamu; Tanaka, Hirotoshi

    2014-10-24

    Pulmonary hypertension (PH) sustains elevation of pulmonary vascular resistance and ultimately leads to right ventricular (RV) hypertrophy and failure and death. Recently, proangiogenic factors hypoxia-inducible factor-1 alpha (HIF-1α) and vascular endothelial growth factor (VEGF) have been known to promote left ventricular myocardial angiogenesis and lead to cardiac hypertrophy, and this would be involved in RV hypertrophy of PH patients. Previously, we revealed that overexpression of HEXIM1 prevents endothelin-1-induced cardiomyocyte hypertrophy and hypertrophic genes expression, and that cardiomyocyte-specific HEXIM1 transgenic mice ameliorates RV hypertrophy in hypoxia-induced PH model. Given these results, here we analyzed the effect of HEXIM1 on the expression of HIF-1α and VEGF and on myocardial angiogenesis of RV in PH. We revealed that overexpression of HEXIM1 prevented hypoxia-induced expression of HIF-1α protein and its target genes including VEGF in the cultured cardiac myocytes and fibroblasts, and that cardiomyocyte-specific HEXIM1 transgenic mice repressed RV myocardial angiogenesis in hypoxia-induced PH model. Thus, we conclude that HEXIM1 could prevent RV hypertrophy, at least in part, via suppression of myocardial angiogenesis through down-regulation of HIF-1α and VEGF in the myocardium under hypoxic condition. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Hypoxic stress simultaneously stimulates vascular endothelial growth factor via hypoxia-inducible factor-1α and inhibits stromal cell-derived factor-1 in human endometrial stromal cells.

    Science.gov (United States)

    Tsuzuki, Tomoko; Okada, Hidetaka; Cho, Hisayuu; Tsuji, Shoko; Nishigaki, Akemi; Yasuda, Katsuhiko; Kanzaki, Hideharu

    2012-02-01

    Hypoxia of the human endometrium is a physiologic event occurring during the perimenstrual period and the local stimulus for angiogenesis. The aim of this study was to investigate the effects of hypoxic stress on the regulation of vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1 (SDF-1/CXCL12), and the potential role of hypoxia-inducible factor-1α (HIF-1α) in the endometrium. Human endometrial stromal cells (ESCs, n= 22 samples) were studied in vitro. ESCs were cultured under hypoxic and normoxic conditions and treated with cobalt chloride (CoCl₂; a hypoxia-mimicking agent) and/or echinomycin, a small-molecule inhibitor of HIF-1α activity. The mRNA levels and production of VEGF and SDF-1 were assessed by real-time PCR and ELISA, respectively. The HIF-1α protein levels were measured using western blot analysis. Hypoxia simultaneously induced the expression of mRNA and production of VEGF and attenuated the expression and production of SDF-1 from ESCs in a time-dependent manner. Similar changes were observed in the ESCs after stimulation with CoCl₂ in a dose-dependent manner. CoCl₂ significantly induced the expression of HIF-1α protein, and its highest expression was observed at 6 h. Echinomycin inhibited hypoxia-induced VEGF production without affecting the HIF-1α protein level and cell toxicity and had no effect on SDF-1 secretion (P hypoxic conditions that could influence angiogenesis in the human endometrium.

  18. Proline-hydroxylated hypoxia-inducible factor 1α (HIF-1α upregulation in human tumours.

    Directory of Open Access Journals (Sweden)

    Cameron E Snell

    Full Text Available The stabilisation of HIF-α is central to the transcriptional response of animals to hypoxia, regulating the expression of hundreds of genes including those involved in angiogenesis, metabolism and metastasis. HIF-α is degraded under normoxic conditions by proline hydroxylation, which allows for recognition and ubiquitination by the von-Hippel-Lindau (VHL E3 ligase complex. The aim of our study was to investigate the posttranslational modification of HIF-1α in tumours, to assess whether there are additional mechanisms besides reduced hydroxylation leading to stability. To this end we optimised antibodies against the proline-hydroxylated forms of HIF-1α for use in formalin fixed paraffin embedded (FFPE immunohistochemistry to assess effects in tumour cells in vivo. We found that HIF-1α proline-hydroxylated at both VHL binding sites (Pro402 and Pro564, was present in hypoxic regions of a wide range of tumours, tumour xenografts and in moderately hypoxic cells in vitro. Staining for hydroxylated HIF-1α can identify a subset of breast cancer patients with poorer prognosis and may be a better marker than total HIF-1α levels. The expression of unhydroxylated HIF-1α positively correlates with VHL in breast cancer suggesting that VHL may be rate-limiting for HIF degradation. Our conclusions are that the degradation of proline-hydroxylated HIF-1α may be rate-limited in tumours and therefore provides new insights into mechanisms of HIF upregulation. Persistence of proline-hydroxylated HIF-1α in perinecrotic areas suggests there is adequate oxygen to support prolyl hydroxylase domain (PHD activity and proline-hydroxylated HIF-1α may be the predominant form associated with the poorer prognosis that higher levels of HIF-1α confer.

  19. The hypoxia factor Hif-1α controls neural crest chemotaxis and epithelial to mesenchymal transition

    Science.gov (United States)

    Barriga, Elias H.; Maxwell, Patrick H.

    2013-01-01

    One of the most important mechanisms that promotes metastasis is the stabilization of Hif-1 (hypoxia-inducible transcription factor 1). We decided to test whether Hif-1α also was required for early embryonic development. We focused our attention on the development of the neural crest, a highly migratory embryonic cell population whose behavior has been likened to cancer metastasis. Inhibition of Hif-1α by antisense morpholinos in Xenopus laevis or zebrafish embryos led to complete inhibition of neural crest migration. We show that Hif-1α controls the expression of Twist, which in turn represses E-cadherin during epithelial to mesenchymal transition (EMT) of neural crest cells. Thus, Hif-1α allows cells to initiate migration by promoting the release of cell–cell adhesions. Additionally, Hif-1α controls chemotaxis toward the chemokine SDF-1 by regulating expression of its receptor Cxcr4. Our results point to Hif-1α as a novel and key regulator that integrates EMT and chemotaxis during migration of neural crest cells. PMID:23712262

  20. HIF-1α-induced HSP70 regulates anabolic responses in articular chondrocytes under hypoxic conditions.

    Science.gov (United States)

    Tsuchida, Shinji; Arai, Yuji; Takahashi, Kenji A; Kishida, Tsunao; Terauchi, Ryu; Honjo, Kuniaki; Nakagawa, Shuji; Inoue, Hiroaki; Ikoma, Kazuya; Ueshima, Keiichiro; Matsuki, Tomohiro; Mazda, Osam; Kubo, Toshikazu

    2014-08-01

    We assessed whether heat shock protein 70 (HSP70) is involved in hypoxia inducible factor 1 alpha (HIF-1α)-dependent anabolic pathways in articular chondrocytes under hypoxic conditions. Primary rabbit chondrocytes were cultured under normoxia (20% oxygen condition) or hypoxia (1% oxygen condition). Alternatively, cells cultured under normoxia were treated with CoCl2 , which induces HIF-1α, to simulate hypoxia, or transfected with siRNAs targeting HIF-1α (si-HIF-1α) and HSP70 (si-HSP70) under hypoxia. HSP70 expression was enhanced by the increased expression of HIF-1α under hypoxia or simulated hypoxia, but not in the presence of si-HIF-1α. Hypoxia-induced overexpression of ECM genes was significantly suppressed by si-HIF-1α or si-HSP70. Cell viability positively correlated with hypoxia, but transfection with si-HIF-1α or si-HSP70 abrogated the chondroprotective effects of hypoxia. Although LDH release from sodium nitroprusside-treated cells and the proportion of TUNEL positive cells were decreased under hypoxia, transfection with si-HIF-1α or si-HSP70 almost completely blocked these effects. These findings indicated that HIF-1α-induced HSP70 overexpression increased the expression levels of ECM genes and cell viability, and protected chondrocytes from apoptosis. HIF-1α may regulate the anabolic effects of chondrocytes under hypoxic conditions by regulating HSP70 expression. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  1. Erythropoietin inhibits HIF-1α expression via upregulation of PHD-2 transcription and translation in an in vitro model of hypoxia-ischemia.

    Science.gov (United States)

    Souvenir, Rhonda; Flores, Jerry J; Ostrowski, Robert P; Manaenko, Anatol; Duris, Kamil; Tang, Jiping

    2014-02-01

    Hypoxia inducible factor (HIF)-1α is the central transcriptional factor for the regulation of oxygen-associated genes in response to hypoxia. Erythropoietin (EPO), a hematopoietic growth factor, increases oxygen availability during hypoxia/ischemia and is associated with neuroprotection following hypoxia-ischemia in laboratory models of stroke. However, EPO has failed to translate in a clinical setting. Thus, it is critical to elucidate the key players in EPO-induced neuroprotection. Our preliminary studies have shown that EPO, as a downstream gene of HIF, inhibits HIF-1α in a dose-dependent manner in an in vitro model of hypoxia-ischemia. This study is designed to elucidate the primary mediator of EPO-induced HIF-1α inhibition and subsequent cell survival/neuroprotection. Oxygen and glucose deprivation (OGD) of nerve growth factor-differentiated rat pheochromocytoma (PC-12) cells were used to model hypoxia-ischemia in an in vitro environment. The profile of HIF-1α, HIF-2α and prolyl hydroxylase domain 2 (PHD-2) expression; HIF-1α and prolyl hydroxylase (PHD-2) mRNA levels; matrix metalloproteinase (MMP)-9; and cell death was evaluated in the presence and absence of either EPO or PHD-2 inhibitor during OGD. Our findings showed that EPO treatment resulted in an increase in PHD-2 transcription and translation, inhibition of HIF-1α expression, reactive oxygen species formation, and MMP-9 activity, resulting in increased cell survival after OGD. We also observed that EPO-induced cell survival/neuroprotection was reversed by siRNA silencing of PHD-2. This led to the conclusion that PHD-2 is a key mediator of EPO-induced HIF-1α inhibition and subsequent neuroprotection in an in vitro model of hypoxia-ischemia.

  2. Hypoxia-Inducible Factor-1α (HIF-1α) Expression on Endothelial Cells in Juvenile Nasopharyngeal Angiofibroma: A Review of 70 cases and Tissue Microarray Analysis.

    Science.gov (United States)

    Song, Xiaole; Yang, Chenhe; Zhang, Huankang; Wang, Jingjing; Sun, Xicai; Hu, Li; Liu, Zhuofu; Wang, Dehui

    2018-06-01

    To examine the expression of hypoxia-inducible factor-1α (HIF-1α) and its related molecules (cellular repressor of E1A-stimulated genes [CREG], osteopontin [OPN], proto-oncogene tyrosine-protein kinase Src [c-Src], and vascular endothelial growth factor [VEGF]) in juvenile nasopharyngeal angiofibroma (JNA) and explore the correlation between clinical prognosis and HIF-1α expression. The study performed a retrospective review of the clinical records of patients with JNA treated between 2003 and 2007. Specimens were analyzed by immunohistochemistry for HIF-1α, CREG, OPN, c-Src, and VEGF expression, and microvessel density (MVD) was assessed by tissue microarray. The correlation between expression levels and clinicopathological features including age, tumor stage, intraoperative blood loss, and recurrence was analyzed. HIF-1α, CREG, OPN, c-Src, and VEGF were upregulated in endothelial cells (ECs) of patients with JNA, and strong correlations in the expression of these molecules were observed. HIF-1α expression was higher in young patients ( P = .032) and in recurrent cases ( P = .01). Survival analysis showed that low HIF-1α levels in ECs predicted longer time to recurrence (log rank test P = .006). Receiver operating characteristic curve analysis showed that HIF-1α was a prognostic factor for recurrence (area under the curve = 0.690, P = .019). No correlation was found between the expression of molecules and Radkowski stage or intraoperative blood loss. In cases of JNA treated surgically, HIF-1α expression in ECs is a useful prognostic factor for tumor recurrence.

  3. Development of 1-aryl-3-furanyl/thienyl-imidazopyridine templates for inhibitors against hypoxia inducible factor (HIF)-1 transcriptional activity.

    Science.gov (United States)

    Fuse, Shinichiro; Ohuchi, Toshiaki; Asawa, Yasunobu; Sato, Shinichi; Nakamura, Hiroyuki

    2016-12-15

    1,3-Disubstituted-imidazopyridines were designed for developing inhibitors against HIF-1 transcriptional activity. Designed compounds were rapidly synthesized from a key aromatic scaffold via microwave-assisted Suzuki-Miyaura coupling/CH direct arylation sequence. Evaluation of ability to inhibit the hypoxia induced transcriptional activity of HIF-1 revealed that the compound 2i and 3a retained the same level of the inhibitory activity comparing with that of known inhibitor, YC-1 (1). Identified, readily accessible 1-aryl-3-furanyl/thienyl-imidazopyridine templates should be useful for future drug development. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Role of hypoxia-inducible factor in diabetic myocardial hypertrophy ...

    African Journals Online (AJOL)

    Purpose: This study was carried out to investigate the role of hypoxia-inducible factor (HIF) in diabetic cardiomyopathy in vitro. Methods: Hypoxia was induced chemically in H9C2 cells (cardiac hypertrophy model), and the cells were treated with phenylephrine (PE), deferoxamine (DFO), PE + DFO, and HIF-1α siRNA under ...

  5. Molecular characterization and mRNA expression of two key enzymes of hypoxia-sensing pathways in eastern oysters Crassostrea virginica (Gmelin): Hypoxia-inducible factor α (HIF-α) and HIF-prolyl hydroxylase (PHD)

    Science.gov (United States)

    Piontkivska, Helen; Chung, J. Sook; Ivanina, Anna V.; Sokolov, Eugene P.; Techa, Sirinart; Sokolova, Inna M.

    2010-01-01

    Oxygen homeostasis is crucial for development, survival and normal function of all metazoans. A family of transcription factors called hypoxia-inducible factors (HIF) is critical in mediating the adaptive responses to reduced oxygen availability. The HIF transcription factor consists of a constitutively expressed β subunit and an oxygen-dependent α subunit; the abundance of the latter determines the activity of HIF and is regulated by a family of O2- and Fe2+-dependent enzymes prolyl hydroxylases (PHDs). Currently very little is known about the function of this important pathway and the molecular structure of its key players in hypoxia-tolerant intertidal mollusks including oysters, which are among the animal champions of anoxic and hypoxic tolerance and thus can serve as excellent models to study the role of HIF cascade in adaptations to oxygen deficiency. We have isolated transcripts of two key components of the oxygen sensing pathway - the oxygen-regulated HIF-α subunit and PHD - from an intertidal mollusk, the eastern oyster Crassostrea virginica, and determined the transcriptional responses of these two genes to anoxia, hypoxia and cadmium (Cd) stress. HIF-α and PHD homologs from eastern oysters C. virginica show significant sequence similarity and share key functional domains with the earlier described isoforms from vertebrates and invertebrates. Phylogenetic analysis shows that genetic diversification of HIF and PHD isoforms occurred within the vertebrate lineage indicating functional diversification and specialization of the oxygen-sensing pathways in this group, which parallels situation observed for many other important genes. HIF-α and PHD homologs are broadly expressed at the mRNA level in different oyster tissues and show transcriptional responses to prolonged hypoxia in the gills consistent with their putative role in oxygen sensing and the adaptive response to hypoxia. Similarity in amino acid sequence, domain structure and transcriptional

  6. Hypoxia-inducible factor 1–mediated characteristic features of cancer cells for tumor radioresistance

    International Nuclear Information System (INIS)

    Harada, Hiroshi

    2016-01-01

    Tumor hypoxia has been attracting increasing attention in the fields of radiation biology and oncology since Thomlinson and Gray detected hypoxic cells in malignant solid tumors and showed that they exert a negative impact on the outcome of radiation therapy. This unfavorable influence has, at least partly, been attributed to cancer cells acquiring a radioresistant phenotype through the activation of the transcription factor, hypoxia-inducible factor 1 (HIF-1). On the other hand, accumulating evidence has recently revealed that, even though HIF-1 is recognized as an important regulator of cellular adaptive responses to hypoxia, it may not become active and induce tumor radioresistance under hypoxic conditions only. The mechanisms by which HIF-1 is activated in cancer cells not only under hypoxic conditions, but also under normoxic conditions, through cancer-specific genetic alterations and the resultant imbalance in intermediate metabolites have been summarized herein. The relevance of the HIF-1–mediated characteristic features of cancer cells, such as the production of antioxidants through reprogramming of the glucose metabolic pathway and cell cycle regulation, for tumor radioresistance has also been reviewed

  7. Hypoxia-inducible factor 1α regulates branching morphogenesis during kidney development.

    Science.gov (United States)

    Tsuji, Kenji; Kitamura, Shinji; Makino, Hirofumi

    2014-04-25

    The kidneys are exposed to hypoxic conditions during development. Hypoxia-inducible factor (HIF), an important mediator of the response to hypoxia, is believed to have an important role in development. However, the relationship between HIF and branching morphogenesis has not been elucidated clearly. In this study, we examined whether HIF regulates kidney development. We harvested kidneys from day 13 rat embryos (E13Ks) and cultured the organs under normoxic (20% O2/5% CO2) or hypoxic (5% O2/5% CO2) conditions. We evaluated the kidneys based on morphology and gene expression. E13Ks cultured under hypoxic conditions had significantly more ureteric bud (UB) branching than the E13Ks cultured under normoxic conditions. In addition, the mRNA levels of GDNF and GDNF receptor (GFR-α1), increased under hypoxic conditions in E13Ks. When we cultured E13Ks with the HIF-1α inhibitor digoxin or with siRNA targeting HIF-1α under hypoxic conditions, we did not observe increased UB branching. In addition, the expression of GDNF and GFR-α1 was inhibited under hypoxic conditions when the kidneys were treated with siRNA targeting HIF-1α. We also elucidated that hypoxia inhibited UB cell apoptosis and promoted the expression of FGF7 mRNA levels in metanephric mesenchymal (MM) cells in vitro. These findings suggest that hypoxic condition has important roles in inducing branching morphogenesis during kidney development. Hypoxia might mediate branching morphogenesis via not only GDNF/Ret but also FGF signaling pathway. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. RNAi Knockdown of Hypoxia-Inducible Factor-1α Decreased the Proliferation, Migration, and Invasion of Hypoxic Hepatocellular Carcinoma Cells.

    Science.gov (United States)

    Chen, ChengShi; Liu, Rong; Wang, JianHua; Yan, ZhiPing; Qian, Sheng; Zhang, Wei

    2015-04-01

    The obstruction of hepatic arterial blood flow results in tumor tissue hypoxia and elevated expression of hypoxia-inducible factor-1alpha (HIF-1α). Our study evaluated whether lentivirus-mediated short interference RNA against HIF-1α inhibits proliferation, invasion, and migration of hepatocellular carcinoma (HCC) cells under hypoxia. RNA interference knockdown of HIF-1α was achieved by HIF-1α-directed lentiviral shRNA, in a rat HCC cell line cultured under hypoxia condition for varying length of times. The expression levels of HIF-1α and vascular endothelial growth factor were examined using reverse transcription polymerase chain reaction and western blot analyses. Cell proliferation, migration, and invasion were measured by cell viability, transwell migration, and invasion assays, respectively. Inhibition of HIF-1α expression by shRNA suppressed vascular endothelial growth factor mRNA and protein levels under both normoxia and hypoxia. It also suppressed cell migration and invasion, which were enhanced under hypoxic conditions. RNAi knockdown of HIF-1α further suppressed hypoxia-mediated inhibition of the cell proliferation. These data suggest that shRNA of HIF-1α could antagonize the hypoxia-mediated increase in hepatic cancer cell migration and invasion, and synergize with hypoxia to inhibit the cell proliferation in HCC cells.

  9. Cinnamic aldehyde suppresses hypoxia-induced angiogenesis via inhibition of hypoxia-inducible factor-1α expression during tumor progression.

    Science.gov (United States)

    Bae, Woom-Yee; Choi, Jae-Sun; Kim, Ja-Eun; Jeong, Joo-Won

    2015-11-01

    During tumor progression, hypoxia-inducible factor 1 (HIF-1) plays a critical role in tumor angiogenesis and tumor growth by regulating the transcription of several genes in response to a hypoxic environment and changes in growth factors. This study was designed to investigate the effects of cinnamic aldehyde (CA) on tumor growth and angiogenesis and the mechanisms underlying CA's anti-angiogenic activities. We found that CA administration inhibits tumor growth and blocks tumor angiogenesis in BALB/c mice. In addition, CA treatment decreased HIF-1α protein expression and vascular endothelial growth factor (VEGF) expression in mouse tumors and Renca cells exposed to hypoxia in vitro. Interestingly, CA treatment did not affect the stability of von Hippel-Lindau protein (pVHL)-associated HIF-1α and CA attenuated the activation of mammalian target of rapamycin (mTOR) pathway. Collectively, these findings strongly indicate that the anti-angiogenic activity of CA is, at least in part, regulated by the mTOR pathway-mediated suppression of HIF-1α protein expression and these findings suggest that CA may be a potential drug for human cancer therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Hypoxia inducible factor-1α-dependent epithelial to mesenchymal transition under hypoxic conditions in prostate cancer cells.

    Science.gov (United States)

    Li, Mingchuan; Wang, Yong Xing; Luo, Yong; Zhao, Jiahui; Li, Qing; Zhang, Jiao; Jiang, Yongguang

    2016-07-01

    Prostate cancer is the most commonly diagnosed cancer in men and the second leading cause of cancer death. Hypoxia is an environmental stimulus that plays an important role in the development and cancer progression especially for solid tumors. The key regulator under hypoxic conditions is stabilized hypoxia-inducible factor (HIF)-1α. In the present study, immune-fluorescent staining, siRNAs, qRT-PC, immunoblotting, cell migration and invasion assays were carried out to test typical epithelial to mesenchymal transition under hypoxia and the key regulators of this process in PC3, a human prostate cancer cell line. Our data demonstrated that hypoxia induces diverse molecular, phenotypic and functional changes in prostate cancer cells that are consistent with EMT. We also showed that a cell signal factor such as HIF-1α, which might be stabilized under hypoxic environment, is involved in EMT and cancer cell invasive potency. The induced hypoxia could be blocked by HIF-1α gene silencing and reoxygenation of EMT in prostate cancer cells, hypoxia partially reversed accompanied by a process of mesenchymal-epithelial reverting transition (MErT). EMT might be induced by activation of HIF-1α-dependent cell signaling in hypoxic prostate cancer cells.

  11. Knockdown of hypoxia-inducible factor-1 alpha reduces proliferation, induces apoptosis and attenuates the aggressive phenotype of retinoblastoma WERI-Rb-1 cells under hypoxic conditions.

    Science.gov (United States)

    Xia, Tian; Cheng, Hao; Zhu, Yu

    2014-01-01

    Hypoxia-inducible factor-1 alpha (HIF-1α) plays a critical role in tumor cell adaption to hypoxia by inducing the transcription of numerous genes. The role of HIF-1α in malignant retinoblastoma remains unclear. We analyzed the role of HIF-1α in WERI-Rb-1 retinoblastoma cells under hypoxic conditions. CoCl2 (125 mmol/L) was added to the culture media to mimic hypoxia. HIF-1α was silenced using siRNA. Gene and protein expression were measured by semi-quantitative RT-PCR and Western blotting. Cell cycle and apoptosis were analyzed by flow cytometry. Cell proliferation, adhesion and invasion were assayed using MTT, Transwell invasion, and cell adhesion assays respectively. Hypoxia significantly upregulated HIF-1α protein expression and the HIF-1α target genes VEGF, GLUT1, and Survivin mRNA. HIF-1α mRNA expression was not affected by hypoxia. Transfection of the siRNA expression plasmid pRNAT-CMV3.2/Neo-HIF-1α silenced HIF-1α by approximately 80% in hypoxic WERI-Rb-1 cells. The knockdown of HIF-1α under hypoxic conditions downregulated VEGF, GLUT1, and Survivin mRNA. It also inhibited proliferation, promoted apoptosis, induced the G0/G1 phase cell cycle arrest, and reduced the adhesion and invasion of WERI-Rb-1 cells. HIF-1α plays a major role in the survival and aggressive phenotype of retinoblastoma cells under hypoxic conditions. Targeting HIF-1α may be a promising therapeutic strategy for human malignant retinoblastoma.

  12. Structural and functional analysis of coral Hypoxia Inducible Factor.

    Directory of Open Access Journals (Sweden)

    Didier Zoccola

    Full Text Available Tissues of symbiotic Cnidarians are exposed to wide, rapid and daily variations of oxygen concentration. Indeed, during daytime, intracellular O2 concentration increases due to symbiont photosynthesis, while during night, respiration of both host cells and symbionts leads to intra-tissue hypoxia. The Hypoxia Inducible Factor 1 (HIF-1 is a heterodimeric transcription factor used for maintenance of oxygen homeostasis and adaptation to hypoxia. Here, we carried out a mechanistic study of the response to variations of O2 concentrations of the coral model Stylophora pistillata. In silico analysis showed that homologs of HIF-1 α (SpiHIF-1α and HIF-1β (SpiHIF-1β exist in coral. A specific SpiHIF-1 DNA binding on mammalian Hypoxia Response Element (HRE sequences was shown in extracts from coral exposed to dark conditions. Then, we cloned the coral HIF-1α and β genes and determined their expression and transcriptional activity. Although HIF-1α has an incomplete Oxygen-dependent Degradation Domain (ODD relative to its human homolog, its protein level is increased under hypoxia when tested in mammalian cells. Moreover, co-transfection of SpiHIF-1α and β in mammalian cells stimulated an artificial promoter containing HRE only in hypoxic conditions. This study shows the strong conservation of molecular mechanisms involved in adaptation to O2 concentration between Cnidarians and Mammals whose ancestors diverged about 1,200-1,500 million years ago.

  13. Structural and functional analysis of coral Hypoxia Inducible Factor.

    Science.gov (United States)

    Zoccola, Didier; Morain, Jonas; Pagès, Gilles; Caminiti-Segonds, Natacha; Giuliano, Sandy; Tambutté, Sylvie; Allemand, Denis

    2017-01-01

    Tissues of symbiotic Cnidarians are exposed to wide, rapid and daily variations of oxygen concentration. Indeed, during daytime, intracellular O2 concentration increases due to symbiont photosynthesis, while during night, respiration of both host cells and symbionts leads to intra-tissue hypoxia. The Hypoxia Inducible Factor 1 (HIF-1) is a heterodimeric transcription factor used for maintenance of oxygen homeostasis and adaptation to hypoxia. Here, we carried out a mechanistic study of the response to variations of O2 concentrations of the coral model Stylophora pistillata. In silico analysis showed that homologs of HIF-1 α (SpiHIF-1α) and HIF-1β (SpiHIF-1β) exist in coral. A specific SpiHIF-1 DNA binding on mammalian Hypoxia Response Element (HRE) sequences was shown in extracts from coral exposed to dark conditions. Then, we cloned the coral HIF-1α and β genes and determined their expression and transcriptional activity. Although HIF-1α has an incomplete Oxygen-dependent Degradation Domain (ODD) relative to its human homolog, its protein level is increased under hypoxia when tested in mammalian cells. Moreover, co-transfection of SpiHIF-1α and β in mammalian cells stimulated an artificial promoter containing HRE only in hypoxic conditions. This study shows the strong conservation of molecular mechanisms involved in adaptation to O2 concentration between Cnidarians and Mammals whose ancestors diverged about 1,200-1,500 million years ago.

  14. Neuroprotection by hypoxic preconditioning involves upregulation of hypoxia-inducible factor-1 in a prenatal model of acute hypoxia.

    Science.gov (United States)

    Giusti, Sebastián; Fiszer de Plazas, Sara

    2012-02-01

    The molecular pathways underlying the neuroprotective effects of preconditioning are promising, potentially drugable targets to promote cell survival. However, these pathways are complex and are not yet fully understood. In this study we have established a paradigm of hypoxic preconditioning based on a chick embryo model of normobaric acute hypoxia previously developed by our group. With this model, we analyzed the role of hypoxia-inducible factor-1α (HIF-1α) stabilization during preconditioning in HIF-1 signaling after the hypoxic injury and in the development of a neuroprotective effect against the insult. To this end, we used a pharmacological approach, based on the in vivo administration of positive (Fe(2+), ascorbate) and negative (CoCl(2)) modulators of the activity of HIF-prolyl hydroxylases (PHDs), the main regulators of HIF-1. We have found that preconditioning has a reinforcing effect on HIF-1 accumulation during the subsequent hypoxic injury. In addition, we have also demonstrated that HIF-1 induction during hypoxic preconditioning is necessary to obtain an enhancement in HIF-1 accumulation and to develop a tolerance against a subsequent hypoxic injury. We provide in vivo evidence that administration of Fe(2+) and ascorbate modulates HIF accumulation, suggesting that PHDs might be targets for neuroprotection in the CNS. Copyright © 2011 Wiley Periodicals, Inc.

  15. Andrographolide inhibits hypoxia-induced hypoxia-inducible factor 1α and endothelin 1 expression through the heme oxygenase 1/CO/cGMP/MKP-5 pathways in EA.hy926 cells.

    Science.gov (United States)

    Lin, Hung-Chih; Su, Shih-Li; Lin, Wan-Chun; Lin, Ai-Hsuan; Yang, Ya-Chen; Lii, Chong-Kuei; Chen, Haw-Wen

    2018-03-01

    Andrographolide is a potent anti-inflammatory agent found in Andrographis paniculata. Endothelin 1 (ET-1) is an endothelium-derived vasoconstrictor with pro-inflammatory properties secreted in response to hypoxia. Mitogen-activated protein kinase phosphatase 5 (MKP-5) is a dual-specificity phosphatase that dephosphorylates threonine and tyrosine residues of MAPKs. We showed previously that hypoxia-induced HIF-1α expression and ET-1 secretion are dependent on p38 MAPK in EA.hy926 cells. Here, we investigate what role MKP-5 plays in andrographolide's inhibition of hypoxia-induced expression of HIF-1α and ET-1. Hypoxic conditions were created using the hypoxia-mimetic agent CoCl 2 . Andrographolide enhanced HO-1 and MKP-5 expression and cellular cGMP content in addition to inhibiting hypoxia-induced ROS generation. Concomitantly, the HO-1 byproduct CO and the cGMP analogue 8-bromoguanosine 3',5'-cyclic monophosphate (8-Br-cGMP) increased MKP-5 expression, and pretreatment with CO and 8-Br-cGMP inhibited hypoxia-induced HIF-1α and ET-1 expression. Transfection of HO-1 siRNA or pretreatment with the HO-1 inhibitor ZnPP-9 or 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a specific inhibitor of soluble guanylate cyclase, reduced andrographolide-induced MKP-5 expression. Moreover, silencing MKP-5 or treatment with the phosphatase inhibitor vanadate abrogated andrographolide's suppressing hypoxia-induced p38 MAPK activation and HIF-1α expression. The inhibition of hypoxia-induced HIF-1α and ET-1 expression by andrographolide is likely associated with HO-1/CO/cGMP/MKP-5 pathways, which is involved in inhibiting hypoxia-induced p38 MAPK activation. © 2017 Wiley Periodicals, Inc.

  16. Peptidyl Prolyl Isomerase PIN1 Directly Binds to and Stabilizes Hypoxia-Inducible Factor-1α.

    Directory of Open Access Journals (Sweden)

    Hyeong-Jun Han

    Full Text Available Peptidyl prolyl isomerase (PIN1 regulates the functional activity of a subset of phosphoproteins through binding to phosphorylated Ser/Thr-Pro motifs and subsequently isomerization of the phosphorylated bonds. Interestingly, PIN1 is overexpressed in many types of malignancies including breast, prostate, lung and colon cancers. However, its oncogenic functions have not been fully elucidated. Here, we report that PIN1 directly interacts with hypoxia-inducible factor (HIF-1α in human colon cancer (HCT116 cells. PIN1 binding to HIF-1α occurred in a phosphorylation-dependent manner. We also found that PIN1 interacted with HIF-1α at both exogenous and endogenous levels. Notably, PIN1 binding stabilized the HIF-1α protein, given that their levels were significantly increased under hypoxic conditions. The stabilization of HIF-1α resulted in increased transcriptional activity, consequently upregulating expression of vascular endothelial growth factor, a major contributor to angiogenesis. Silencing of PIN1 or pharmacologic inhibition of its activity abrogated the angiogenesis. By utilizing a bioluminescence imaging technique, we were able to demonstrate that PIN1 inhibition dramatically reduced the tumor volume in a subcutaneous mouse xenograft model and angiogenesis as well as hypoxia-induced transcriptional activity of HIF-1α. These results suggest that PIN1 interacting with HIF-1α is a potential cancer chemopreventive and therapeutic target.

  17. Anti-vascular agent Combretastatin A-4-P modulates Hypoxia Inducible Factor-1 and gene expression

    Directory of Open Access Journals (Sweden)

    Currie Margaret J

    2006-12-01

    Full Text Available Abstract Background A functional vascular network is essential for the survival, growth and spread of solid tumours, making blood vessels a key target for therapeutic strategies. Combretastatin A-4 phosphate (CA-4-P is a tubulin-depolymerising agent in Phase II clinical trials as a vascular disrupting agent. Not much is known of the molecular effect of CA-4-P under tumour conditions. The tumour microenvironment differs markedly from that in normal tissue, specifically with respect to oxygenation (hypoxia. Gene regulation under tumour conditions is governed by hypoxia inducible factor 1 (HIF-1, controlling angiogenic and metastatic pathways. Methods We investigated the effect of CA-4-P on factors of the upstream and downstream signalling pathway of HIF-1 in vitro. Results CA-4-P treatment under hypoxia tended to reduce HIF-1 accumulation in a concentration-dependent manner, an effect which was more prominent in endothelial cells than in cancer cell lines. Conversely, CA-4-P increased HIF-1 accumulation under aerobic conditions in vitro. At these concentrations of CA-4-P under aerobic conditions, nuclear factor κB was activated via the small GTPase RhoA, and expression of the HIF-1 downstream angiogenic effector gene, vascular endothelial growth factor (VEGF-A, was increased. Conclusion Our findings advance the understanding of signal transduction pathways involved in the actions of the anti-vascular agent CA-4-P.

  18. Hypoxia-Induced Autophagy Is Mediated through Hypoxia-Inducible Factor Induction of BNIP3 and BNIP3L via Their BH3 Domains▿ †

    OpenAIRE

    Bellot, Grégory; Garcia-Medina, Raquel; Gounon, Pierre; Chiche, Johanna; Roux, Danièle; Pouysségur, Jacques; Mazure, Nathalie M.

    2009-01-01

    While hypoxia-inducible factor (HIF) is a major actor in the cell survival response to hypoxia, HIF also is associated with cell death. Several studies implicate the HIF-induced putative BH3-only proapoptotic genes bnip3 and bnip3l in hypoxia-mediated cell death. We, like others, do not support this assertion. Here, we clearly demonstrate that the hypoxic microenvironment contributes to survival rather than cell death by inducing autophagy. The ablation of Beclin1, a major actor of autophagy,...

  19. Small interfering RNA targeting HIF-1{alpha} reduces hypoxia-dependent transcription and radiosensitizes hypoxic HT 1080 human fibrosarcoma cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Staab, Adrian [Wuerzburg Univ. (Germany). Dept. of Radiation Oncology; Paul Scherrer Institute (PSI), Villigen (Switzerland); Fleischer, Markus [Wuerzburg Univ. (Germany). Dept. of Radiation Oncology; Wuerzburg Univ. (Germany). Medical Clinic II; Loeffler, Juergen; Einsele, Herrmann [Wuerzburg Univ. (Germany). Medical Clinic II; Said, Harun M.; Katzer, Astrid; Flentje, Michael [Wuerzburg Univ. (Germany). Dept. of Radiation Oncology; Plathow, Christian [Freiburg Univ. (Germany). Dept. of Nuclear Medicine; Vordermark, Dirk [Wuerzburg Univ. (Germany). Dept. of Radiation Oncology; Halle-Wittenberg Univ. (Germany). Dept. of Radiation Oncology

    2011-04-15

    Background: Hypoxia inducible factor-1 has been identified as a potential target to overcome hypoxia-induced radioresistance The aim of the present study was to investigate whether selective HIF-1 inhibition via small interfering RNA (siRNA) targeting hypoxia-inducible factor 1{alpha} (HIF-1{alpha}) affects hypoxia-induced radioresistance in HT 1080 human fibrosarcoma cells. Material and Methods: HIF-1{alpha} expression in HT 1080 human fibrosarcoma cells in vitro was silenced using HIF-1{alpha} siRNA sequence primers. Quantitative real-time polymerase chain reaction assay was performed to quantify the mRNA expression of HIF-1{alpha}. HIF-1{alpha} protein levels were studied by Western blotting at 20% (air) or after 12 hours at 0.1% O{sub 2} (hypoxia). Cells were assayed for clonogenic survival after irradiation with 2, 5, or 10 Gy, under normoxic or hypoxic conditions in the presence of HIF-1{alpha}-targeted or control siRNA sequences. A modified oxygen enhancement ratio (OER') was calculated as the ratio of the doses to achieve the same survival at 0.1% O{sub 2} as at ambient oxygen tensions. OER' was obtained at cell survival levels of 50%, 37%, and 10%. Results: HIF-1{alpha}-targeted siRNA enhanced radiation treatment efficacy under severely hypoxic conditions compared to tumor cells treated with scrambled control siRNA. OER was reduced on all survival levels after treatment with HIF-1{alpha}-targeted siRNA, suggesting that inhibition of HIF-1 activation by using HIF-1{alpha}-targeted siRNA increases radiosensitivity of hypoxic tumor cells in vitro. Conclusion: Inhibition of HIF-1 activation by using HIF-1{alpha}-targeted siRNA clearly acts synergistically with radiotherapy and increase radiosensitivity of hypoxic cells in vitro. (orig.)

  20. Small interfering RNA targeting HIF-1α reduces hypoxia-dependent transcription and radiosensitizes hypoxic HT 1080 human fibrosarcoma cells in vitro

    International Nuclear Information System (INIS)

    Staab, Adrian; Fleischer, Markus; Wuerzburg Univ.; Loeffler, Juergen; Einsele, Herrmann; Said, Harun M.; Katzer, Astrid; Flentje, Michael; Plathow, Christian; Vordermark, Dirk; Halle-Wittenberg Univ.

    2011-01-01

    Background: Hypoxia inducible factor-1 has been identified as a potential target to overcome hypoxia-induced radioresistance The aim of the present study was to investigate whether selective HIF-1 inhibition via small interfering RNA (siRNA) targeting hypoxia-inducible factor 1α (HIF-1α) affects hypoxia-induced radioresistance in HT 1080 human fibrosarcoma cells. Material and Methods: HIF-1α expression in HT 1080 human fibrosarcoma cells in vitro was silenced using HIF-1α siRNA sequence primers. Quantitative real-time polymerase chain reaction assay was performed to quantify the mRNA expression of HIF-1α. HIF-1α protein levels were studied by Western blotting at 20% (air) or after 12 hours at 0.1% O 2 (hypoxia). Cells were assayed for clonogenic survival after irradiation with 2, 5, or 10 Gy, under normoxic or hypoxic conditions in the presence of HIF-1α-targeted or control siRNA sequences. A modified oxygen enhancement ratio (OER') was calculated as the ratio of the doses to achieve the same survival at 0.1% O 2 as at ambient oxygen tensions. OER' was obtained at cell survival levels of 50%, 37%, and 10%. Results: HIF-1α-targeted siRNA enhanced radiation treatment efficacy under severely hypoxic conditions compared to tumor cells treated with scrambled control siRNA. OER was reduced on all survival levels after treatment with HIF-1α-targeted siRNA, suggesting that inhibition of HIF-1 activation by using HIF-1α-targeted siRNA increases radiosensitivity of hypoxic tumor cells in vitro. Conclusion: Inhibition of HIF-1 activation by using HIF-1α-targeted siRNA clearly acts synergistically with radiotherapy and increase radiosensitivity of hypoxic cells in vitro. (orig.)

  1. Hypoxia-inducible factor-1α expression requires PI 3-kinase activity and correlates with Akt1 phosphorylation in invasive breast carcinomas

    NARCIS (Netherlands)

    Gort, E.H.; Groot, A.J.; Derks van de Ven, T.L.P.; Groep, P. van der; Verlaan, I.; Laar, T. van; Diest, P.J. van; Wall, E. van der; Shvarts, A.

    2006-01-01

    Hypoxia-inducible factor-1 alpha (HIF-1a) is the regulatory subunit of the heterodimeric transcription factor HIF-1 and the key factor in cellular response to low oxygen tension. Expression of HIF-1a protein is associated with poor patient survival and therapy resistance in many types of solid

  2. Study on radiation regulation of hypoxia inducible factor-1α expression and its correlation with hepatoma radiosensitivity

    International Nuclear Information System (INIS)

    Jin Wensen; Kong Zhaolu; Shen Zhifen; Tong Shungao; Ji Huajun; Jin Yizun

    2008-01-01

    Objective: To study the regulation of hypoxia inducible factor-1α (HIF-1α) expression in hepatoma cells after irradiation and the expression of HIF-1α effect on the radiosensitivity of heptoma cells. Methods: HepG2 cells were pretreated by Cobalt chloride (COCl 2 ), a chemical hypoxia agent, to induce and stabilize the expression of HIF-1α, and then exposed to different γ-irradiation doses. Clonogenic assay was used to evaluate HepG2 cell survival fraction (SF) after irradiation under normoxia and chemical hypoxia. Reverse transcriptase polymerase chain reaction (RT-PCR) and immunoblot assay (Western blot) were utilized to detect the changes of intracellular HIF-1α on the level of transcripation and translation. Results: Cell survival level was elevated by chemical hypoxia and there was a statistical difference between chemical hypoxic group and normoxic group. The ratios of SF(SF co /SF o 2 )on two different conditions were increased with irradiation doses. Meanwhile, the irradiation induced up-regulation of HIF-1α in dose-dependent manner. The expression of HIF-1α was correlated with HepG2 cell survival level to some extent. Conclusions: Irradiation could up-regulate the level of HIF-1α expression in HepG2 cells under chemical hypoxic condition. The cells survival level might be influenced by the changes in HIF-1α expression. (authors)

  3. A New Pharmacological Agent (AKB-4924) Stabilizes Hypoxia Inducible Factor (HIF) and Increases Skin Innate Defenses Against Bacterial Infection

    Science.gov (United States)

    Okumura, Cheryl Y.M.; Hollands, Andrew; Tran, Dan N.; Olson, Joshua; Dahesh, Samira; von Köckritz-Blickwede, Maren; Thienphrapa, Wdee; Corle, Courtney; Jeung, Seung Nam; Kotsakis, Anna; Shalwitz, Robert A.; Johnson, Randall S.; Nizet, Victor

    2013-01-01

    Hypoxia inducible factor-1 (HIF-1) is a transcription factor that is a major regulator of energy homeostasis and cellular adaptation to low oxygen stress. HIF-1 is also activated in response to bacterial pathogens and supports the innate immune response of both phagocytes and keratinocytes. In this work, we show that a new pharmacological compound AKB-4924 (Akebia Therapeutics) increases HIF-1α levels and enhances the antibacterial activity of phagocytes and keratinocytes against both methicillin-sensitive and -resistant strains of Staphylococcus aureus in vitro. AKB-4924 is also effective in stimulating the killing capacity of keratinocytes against the important opportunistic skin pathogens Pseudomonas aeruginosa and Acinitobacter baumanii. The effect of AKB-4924 is mediated through the activity of host cells, as the compound exerts no direct antimicrobial activity. Administered locally as a single agent, AKB-4924 limits S. aureus proliferation and lesion formation in a mouse skin abscess model. This approach to pharmacologically boost the innate immune response via HIF-1 stabilization may serve as a useful adjunctive treatment for antibiotic-resistant bacterial infections. PMID:22371073

  4. Caffeic acid phenethyl ester inhibits 3-MC-induced CYP1A1 expression through induction of hypoxia-inducible factor-1α

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung Gyun [Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon (Korea, Republic of); Han, Eun Hee [Division of Life Science, Korea Basic Science Institute, Daejeon (Korea, Republic of); Im, Ji Hye; Lee, Eun Ji; Jin, Sun Woo [Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon (Korea, Republic of); Jeong, Hye Gwang, E-mail: hgjeong@cnu.ac.kr [Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon (Korea, Republic of)

    2015-09-25

    Caffeic acid phenethyl ester (CAPE), a natural component of propolis, is reported to have anticarcinogenic properties, although its precise chemopreventive mechanism remains unclear. In this study, we examined the effects of CAPE on 3-methylcholanthrene (3-MC)-induced CYP1A1 expression and activities. CAPE reduced the formation of the benzo[a]pyrene-DNA adduct. Moreover, CAPE inhibited 3-MC-induced CYP1A1 activity, mRNA expression, protein level, and promoter activity. CAPE treatment also decreased 3-MC-inducible xenobiotic-response element (XRE)-linked luciferase, aryl hydrocarbons receptor (AhR) transactivation and nuclear localization. CAPE induced hypoxia inducible factor-1α (HIF-1α) protein level and HIF-1α responsible element (HRE) transcriptional activity. CAPE-mediated HIF-1α reduced 3-MC-inducible CYP1A1 protein expression. Taken together, CAPE decreases 3-MC-mediated CYP1A1 expression, and this inhibitory response is associated with inhibition of AhR and HIF-1α induction. - Highlights: • CAPE reduced the formation of the benzo[a]pyrene-DNA adduct. • CAPE inhibited 3-MC-induced CYP1A1 expression. • CAPE induced HIF-1α induction. • CAPE-mediated HIF-1α reduced 3-MC-inducible CYP1A1 expression.

  5. Clinical Aspects of Hypoxia-inducible Factors in Colorectal Cancer

    DEFF Research Database (Denmark)

    Havelund, Birgitte Mayland; Spindler, Karen-Lise Garm; Sørensen, Flemming Brandt

    2010-01-01

    Clinical Aspects of Hypoxia-inducible Factors in Colorectal Cancer  Birgitte Mayland Havelund1,4 MD, Karen-Lise Garm Spindler1,4 MD, PhD, Flemming Brandt Sørensen2,4 MD, DMSc, Ivan Brandslund3 MD, DMSc, Anders Jakobsen1,4 MD, DMSc.1Department of Oncology, 2Pathology and 3Biochemistry, Vejle...... Hospital, Vejle, Denmark4Institute of Regional Health Services Research, University of Southern Denmark, Odense DenmarkBackgroundPrognostic and predictive markers are needed for individualizing the treatment of colorectal cancer. Hypoxia-inducible factor 1α (HIF-1α) is a transcription-inducing factor which...... the predictive and prognostic value of HIF-1α in colorectal cancer.Materials and MethodsThe project is divided into 3 substudies:1. Biological and methodological aspects. The expression of HIF-1α measured by immunohistochemistry in paraffin embedded tissue is related to single nucleotide polymorphism (SNP...

  6. A3 Adenosine Receptors Modulate Hypoxia-inducible Factor-1a Expression in Human A375 Melanoma Cells

    Directory of Open Access Journals (Sweden)

    Stefania Merighi

    2005-10-01

    Full Text Available Hypoxia-inducible factor-1 (HIF-1 is a key regulator of genes crucial to many aspects of cancer biology. The purine nucleoside, adenosine, accumulates within many tissues under hypoxic conditions, including that of tumors. Because the levels of both HIF-1 and adenosine are elevated within the hypoxic environment of solid tumors, we investigated whether adenosine may regulate HIF-1. Here we show that, under hypoxic conditions (< 2% 02, adenosine upregulates HIF-1α protein expression in a dose-dependent and timedependent manner, exclusively through the A3 receptor subtype. The response to adenosine was generated at the cell surface because the inhibition of A3 receptor expression, by using small interfering RNA, abolished nucleoside effects. A3 receptor stimulation in hypoxia also increases angiopoietin-2 (Ang-2 protein accumulation through the induction of HIF-1α. In particular, we found that A3 receptor stimulation activates p44/p42 and p38 mitogen-activated protein kinases, which are required for A3-induced increase of HIF-1a and Ang-2. Collectively, these results suggest a cooperation between hypoxic and adenosine signals that ultimately may lead to the increase in HIF-1-mediated effects in cancer cells.

  7. Fibroblast-Specific Deletion of Hypoxia Inducible Factor-1 Critically Impairs Murine Cutaneous Neovascularization and Wound Healing.

    Science.gov (United States)

    Duscher, Dominik; Maan, Zeshaan N; Whittam, Alexander J; Sorkin, Michael; Hu, Michael S; Walmsley, Graham G; Baker, Hutton; Fischer, Lauren H; Januszyk, Michael; Wong, Victor W; Gurtner, Geoffrey C

    2015-11-01

    Diabetes and aging are known risk factors for impaired neovascularization in response to ischemic insult, resulting in chronic wounds, and poor outcomes following myocardial infarction and cerebrovascular injury. Hypoxia-inducible factor (HIF)-1α, has been identified as a critical regulator of the response to ischemic injury and is dysfunctional in diabetic and elderly patients. To better understand the role of this master hypoxia regulator within cutaneous tissue, the authors generated and evaluated a fibroblast-specific HIF-1α knockout mouse model. The authors generated floxed HIF-1 mice (HIF-1) by introducing loxP sites around exon 1 of the HIF-1 allele in C57BL/6J mice. Fibroblast-restricted HIF-1α knockout (FbKO) mice were generated by breeding our HIF-1 with tamoxifen-inducible Col1a2-Cre mice (Col1a2-CreER). HIF-1α knockout was evaluated on a DNA, RNA, and protein level. Knockout and wild-type mice were subjected to ischemic flap and wound healing models, and CD31 immunohistochemistry was performed to assess vascularity of healed wounds. Quantitative real-time polymerase chain reaction of FbKO skin demonstrated significantly reduced Hif1 and Vegfa expression compared with wild-type. This finding was confirmed at the protein level (p wound closure and vascularity (p wound healing, reduced wound vascularity, and significant impairment in the ischemic neovascular response. These findings provide new insight into the importance of cell-specific responses to hypoxia during cutaneous neovascularization.

  8. Celecoxib Down-Regulates the Hypoxia-Induced Expression of HIF-1α and VEGF Through the PI3K/AKT Pathway in Retinal Pigment Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Yi-zhou Sun

    2017-12-01

    Full Text Available Background/Aims: The goal of this study was to detect the expression of hypoxia-inducible factor 1α (HIF-1α and vascular endothelial growth factor (VEGF in human retinal pigmented epithelial (RPE cells treated with celecoxib, a selective cyclooxygenase-2 (COX-2 inhibitor, under hypoxic and normoxic conditions and to explore the signaling mechanism involved in regulating the hypoxia-induced expression of HIF-1α and VEGF in RPE cells. Methods: D407 cells were cultured in normoxic or hypoxic conditions, with or without celecoxib or a PI3K inhibitor (LY294002. The anti-proliferative effect of celecoxib was assessed using the MTT assay. RT-PCR, Western blotting and ELISA were performed to detect the levels of PI3K, phosphorylated AKT (p-AKT, HIF-1α, VEGF and COX-2. Results: Celecoxib inhibited the proliferation of RPE cells in a dose-dependent manner. Celecoxib suppressed the expression of VEGF at both the mRNA and protein levels and decreased HIF-1α protein expression. HIF-1α activation was regulated by the PI3K/AKT pathway. The celecoxib-induced down-regulation of HIF-1α and VEGF required the suppression of the hypoxia-induced PI3K/AKT pathway. However, the down-regulation of COX-2 did not occur in cells treated with celecoxib. Conclusions: The antiangiogenic effects of celecoxib in RPE cells under hypoxic conditions resulted from the inhibition of HIF-1α and VEGF expression, which may be partly mediated by a COX-2-independent, PI3K/AKT-dependent pathway.

  9. Chronic deficiency of nitric oxide affects hypoxia inducible factor-1α (HIF-1α stability and migration in human endothelial cells.

    Directory of Open Access Journals (Sweden)

    Maria Grazia Cattaneo

    Full Text Available BACKGROUND: Endothelial dysfunction in widely diffuse disorders, such as atherosclerosis, hypertension, diabetes and senescence, is associated with nitric oxide (NO deficiency. Here, the behavioural and molecular consequences deriving from NO deficiency in human umbilical vein endothelial cells (HUVECs were investigated. RESULTS: Endothelial nitric oxide synthase (eNOS was chronically inhibited either by N(G-Nitro-L-arginine methyl ester (L-NAME treatment or its expression was down-regulated by RNA interference. After long-term L-NAME treatment, HUVECs displayed a higher migratory capability accompanied by an increased Vascular Endothelial Growth Factor (VEGF and VEGF receptor-2 (kinase insert domain receptor, KDR expression. Moreover, both pharmacological and genetic inhibition of eNOS induced a state of pseudohypoxia, revealed by the stabilization of hypoxia-inducible factor-1α (HIF-1α. Furthermore, NO loss induced a significant decrease in mitochondrial mass and energy production accompanied by a lower O(2 consumption. Notably, very low doses of chronically administered DETA/NO reverted the HIF-1α accumulation, the increased VEGF expression and the stimulated migratory behaviour detected in NO deficient cells. CONCLUSION: Based on our results, we propose that basal release of NO may act as a negative controller of HIF-1α levels with important consequences for endothelial cell physiology. Moreover, we suggest that our experimental model where eNOS activity was impaired by pharmacological and genetic inhibition may represent a good in vitro system to study endothelial dysfunction.

  10. Hypoxia inducible factor-1 alpha stabilization for regenerative therapy in traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Mushfiquddin Khan

    2017-01-01

    Full Text Available Mild traumatic brain injury (TBI, also called concussion, initiates sequelae leading to motor deficits, cognitive impairments and subtly compromised neurobehaviors. While the acute phase of TBI is associated with neuroinflammation and nitroxidative burst, the chronic phase shows a lack of stimulation of the neurorepair process and regeneration. The deficiency of nitric oxide (NO, the consequent disturbed NO metabolome, and imbalanced mechanisms of S-nitrosylation are implicated in blocking the mechanisms of neurorepair processes and functional recovery in the both phases. Hypoxia inducible factor-1 alpha (HIF-1α, a master regulator of hypoxia/ischemia, stimulates the process of neurorepair and thus aids in functional recovery after brain trauma. The activity of HIF-1α is regulated by NO via the mechanism of S-nitrosylation of HIF-1α. S-nitrosylation is dynamically regulated by NO metabolites such as S-nitrosoglutathione (GSNO and peroxynitrite. GSNO stabilizes, and peroxynitrite destabilizes HIF-1α. Exogenously administered GSNO was found not only to stabilize HIF-1α and to induce HIF-1α-dependent genes but also to stimulate the regeneration process and to aid in functional recovery in TBI animals.

  11. HIF-1alpha and HIF-2alpha are differentially activated in distinct cell populations in retinal ischaemia.

    Directory of Open Access Journals (Sweden)

    Freya M Mowat

    2010-06-01

    Full Text Available Hypoxia plays a key role in ischaemic and neovascular disorders of the retina. Cellular responses to oxygen are mediated by hypoxia-inducible transcription factors (HIFs that are stabilised in hypoxia and induce the expression of a diverse range of genes. The purpose of this study was to define the cellular specificities of HIF-1alpha and HIF-2alpha in retinal ischaemia, and to determine their correlation with the pattern of retinal hypoxia and the expression profiles of induced molecular mediators.We investigated the tissue distribution of retinal hypoxia during oxygen-induced retinopathy (OIR in mice using the bio-reductive drug pimonidazole. We measured the levels of HIF-1alpha and HIF-2alpha proteins by Western blotting and determined their cellular distribution by immunohistochemistry during the development of OIR. We measured the temporal expression profiles of two downstream mediators, vascular endothelial growth factor (VEGF and erythropoietin (Epo by ELISA. Pimonidazole labelling was evident specifically in the inner retina. Labelling peaked at 2 hours after the onset of hypoxia and gradually declined thereafter. Marked binding to Müller glia was evident during the early hypoxic stages of OIR. Both HIF-1alpha and HIF-2alpha protein levels were significantly increased during retinal hypoxia but were evident in distinct cellular distributions; HIF-1alpha stabilisation was evident in neuronal cells throughout the inner retinal layers whereas HIF-2alpha was restricted to Müller glia and astrocytes. Hypoxia and HIF-alpha stabilisation in the retina were closely followed by upregulated expression of the downstream mediators VEGF and EPO.Both HIF-1alpha and HIF-2alpha are activated in close correlation with retinal hypoxia but have contrasting cell specificities, consistent with differential roles in retinal ischaemia. Our findings suggest that HIF-2alpha activation plays a key role in regulating the response of Müller glia to hypoxia.

  12. Mipu1, a novel direct target gene, is involved in hypoxia inducible factor 1-mediated cytoprotection.

    Directory of Open Access Journals (Sweden)

    Kangkai Wang

    Full Text Available Mipu1 (myocardial ischemic preconditioning up-regulated protein 1, recently identified in our lab, is a novel zinc-finger transcription factor which is up-regulated during ischemic preconditioning. However, it is not clear what transcription factor contributes to its inducible expression. In the present study, we reported that HIF-1 regulates the inducible expression of Mipu1 which is involved in the cytoprotection of HIF-1α against oxidative stress by inhibiting Bax expression. Our results showed that the inducible expression of Mipu1 was associated with the expression and activation of transcription factor HIF-1 as indicated by cobalt chloride (CoCl2 treatment, HIF-1α overexpression and knockdown assays. EMSA and luciferase reporter gene assays showed that HIF-1α bound to the hypoxia response element (HRE within Mipu1 promoter region and promoted its transcription. Moreover, our results revealed that Mipu1 inhibited the expression of Bax, an important pro-apoptosis protein associated with the intrinsic pathway of apoptosis, elevating the cytoprotection of HIF-1 against hydrogen peroxide (H2O2-mediated injury in H9C2 cells. Our findings implied that Bax may be a potential target gene of transcription factor Mipu1, and provided a novel insight for understanding the cytoprotection of HIF-1 and new clues for further elucidating the mechanisms by which Mipu1 protects cell against pathological stress.

  13. Hypoxia-inducible factor 1-alpha up-regulates the expression of phospholipase D2 in colon cancer cells under hypoxic conditions.

    Science.gov (United States)

    Liu, Maoxi; Du, Kunli; Fu, Zhongxue; Zhang, Shouru; Wu, Xingye

    2015-01-01

    Hypoxia is a common characteristic of solid tumors. Recent studies confirmed that phospholipase D2 (PLD2) plays significant roles in cancer progression. In this study, correlation between the expression of PLD2 and the change in the protein level of hypoxia-inducible factor 1-alpha (HIF1-α) was studied. Thirty human colon cancer tissues were examined for the expression of HIF1-α and PLD2 protein, and mRNA levels. SW480 and SW620 cells were exposed to normoxia (20 %) or hypoxia (Hypoxic stress induced PLD2 mRNA and protein expression in SW480 and SW620 cells. Cells transfected with HIF1-α siRNA showed attenuation of hypoxia stress-induced PLD2 expression. In vivo growth decreased in response to HIF1-α and PLD2 inhibition. These results suggest that PLD2 expression in colon cancer cells is up-regulated via HIF1-α in response to hypoxic stress and underscores the crucial role of HIF1-α-induced PLD2 in tumor growth.

  14. Hypoxia promotes apoptosis of neuronal cells through hypoxia-inducible factor-1α-microRNA-204-B-cell lymphoma-2 pathway.

    Science.gov (United States)

    Wang, Xiuwen; Li, Ji; Wu, Dongjin; Bu, Xiangpeng; Qiao, Yong

    2016-01-01

    Neuronal cells are highly sensitive to hypoxia and may be subjected to apoptosis when exposed to hypoxia. Several apoptosis-related genes and miRNAs involve in hypoxia-induced apoptosis. This study aimed to examine the role of HIF1α-miR-204-BCL-2 pathway in hypoxia-induced apoptosis in neuronal cells. Annexin V/propidium iodide assay was performed to analyze cell apoptosis in AGE1.HN and PC12 cells under hypoxic or normoxic conditions. The expression of BCL-2 and miR-204 were determined by Western blot and qRT-PCR. The effects of miR-204 overexpression or knockdown on the expression of BCL-2 were evaluated by luciferase assay and Western blot under hypoxic or normoxic conditions. HIF-1α inhibitor YC-1 and siHIF-1α were employed to determine the effect of HIF-1α on the up-regulation of miR-204 and down-regulation of BCL-2 induced by hypoxia. Apoptosis assay showed the presence of apoptosis induced by hypoxia in neuronal cells. Moreover, we found that hypoxia significantly down-regulated the expression of BCL-2, and increased the mRNA level of miR-204 in neuronal cells than that in control. Bioinformatic analysis and luciferase reporter assay demonstrated that miR-204 directly targeted and regulated the expression of BCL-2. Specifically, the expression of BCL-2 was inhibited by miR-204 mimic and enhanced by miR-204 inhibitor. Furthermore, we detected that hypoxia induced cell apoptosis via HIF-1α/miR-204/BCL-2 in neuronal cells. This study demonstrated that HIF-1α-miR-204-BCL-2 pathway contributed to apoptosis of neuronal cells induced by hypoxia, which could potentially be exploited to prevent spinal cord ischemia-reperfusion injury. © 2015 by the Society for Experimental Biology and Medicine.

  15. Transient ureteral obstruction prevents against kidney ischemia/reperfusion injury via hypoxia-inducible factor (HIF-2α activation.

    Directory of Open Access Journals (Sweden)

    Shun Zhang

    Full Text Available Although the protective effect of transient ureteral obstruction (UO prior to ischemia on subsequent renal ischemia/reperfusion (I/R injury has been documented, the underlying molecular mechanism remains to be understood. We showed in the current study that 24 h of UO led to renal tubular hypoxia in the ipsilateral kidney in mice, with the accumulation of hypoxia-inducible factor (HIF-2α, which lasted for a week after the release of UO. To address the functions of HIF-2α in UO-mediated protection of renal IRI, we utilized the Mx-Cre/loxP recombination system to knock out target genes. Inactivation of HIF-2α, but not HIF-1α blunted the renal protective effects of UO, as demonstrated by much higher serum creatinine level and severer histological damage. UO failed to prevent postischemic neutrophil infiltration and apoptosis induction in HIF-2α knockout mice, which also diminished the postobstructive up-regulation of the protective molecule, heat shock protein (HSP-27. The renal protective effects of UO were associated with the improvement of the postischemic recovery of intra-renal microvascular blood flow, which was also dependent on the activation of HIF-2α. Our results demonstrated that UO protected the kidney via activation of HIF-2α, which reduced tubular damages via preservation of adequate renal microvascular perfusion after ischemia. Thus, preconditional HIF-2α activation might serve as a novel therapeutic strategy for the treatment of ischemic acute renal failure.

  16. The role of hypoxia inducible factor 1 (HIF-1) in hypoxia induced apoptosis

    NARCIS (Netherlands)

    Greijer, A.E.; Wall, E. van der

    2004-01-01

    Apoptosis can be induced in response to hypoxia. The severity of hypoxia determines whether cells become apoptotic or adapt to hypoxia and survive. A hypoxic environment devoid of nutrients prevents the cell undergoing energy dependent apoptosis and cells become necrotic. Apoptosis regulatory

  17. Inhibition of hypoxia inducible factor 1 and topoisomerase with acriflavine sensitizes perihilar cholangiocarcinomas to photodynamic therapy

    NARCIS (Netherlands)

    Weijer, Ruud; Broekgaarden, Mans; Krekorian, Massis; Alles, Lindy K.; van Wijk, Albert C.; Mackaaij, Claire; Verheij, Joanne; van der Wal, Allard C.; van Gulik, Thomas M.; Storm, Gert; Heger, Michal

    2016-01-01

    Photodynamic therapy (PDT) induces tumor cell death by oxidative stress and hypoxia but also survival signaling through activation of hypoxia-inducible factor 1 (HIF-1). Since perihilar cholangiocarcinomas are relatively recalcitrant to PDT, the aims were to (1) determine the expression levels of

  18. Inhibition of hypoxia inducible factor 1 and topoisomerase with acriflavine sensitizes perihilar cholangiocarcinomas to photodynamic therapy

    NARCIS (Netherlands)

    Weijer, R.; Broekgaarden, M.; Krekorian, M.; Alles, L.K.; van Wijk, A.C; Mackaaij, C.; Verheij, J.; van der Wal, A.C.; van Gullik, T.M.; Storm, Gerrit; Heger, M.

    2016-01-01

    Background: Photodynamic therapy (PDT) induces tumor cell death by oxidative stress and hypoxia but also survival signaling through activation of hypoxia-inducible factor 1 (HIF-1). Since perihilar cholangiocarcinomas are relatively recalcitrant to PDT, the aims were to (1) determine the expression

  19. The metal-responsive transcription factor-1 contributes to HIF-1 activation during hypoxic stress

    International Nuclear Information System (INIS)

    Murphy, Brian J.; Sato, Barbara G.; Dalton, Timothy P.; Laderoute, Keith R.

    2005-01-01

    Hypoxia-inducible factor-1 (HIF-1), the major transcriptional regulator of the mammalian cellular response to low oxygen (hypoxia), is embedded within a complex network of signaling pathways. We have been investigating the importance of another stress-responsive transcription factor, MTF-1, for the adaptation of cells to hypoxia. This article reports that MTF-1 plays a central role in hypoxic cells by contributing to HIF-1 activity. Loss of MTF-1 in transformed Mtf1 null mouse embryonic fibroblasts (MEFs) results in an attenuation of nuclear HIF-1α protein accumulation, HIF-1 transcriptional activity, and expression of an established HIF-1 target gene, glucose transporter-1 (Glut1). Mtf1 null (Mtf1 KO) MEFs also have constitutively higher levels of both glutathione (GSH) and the rate-limiting enzyme involved in GSH synthesis-glutamate cysteine ligase catalytic subunit-than wild type cells. The altered cellular redox state arising from increased GSH may perturb oxygen-sensing mechanisms in hypoxic Mtf1 KO cells and decrease the accumulation of HIF-1α protein. Together, these novel findings define a role for MTF-1 in the regulation of HIF-1 activity

  20. Hypoxia-inducible factor 1α mediates neuroprotection of hypoxic postconditioning against global cerebral ischemia.

    Science.gov (United States)

    Zhu, Tingna; Zhan, Lixuan; Liang, Donghai; Hu, Jiaoyue; Lu, Zhiwei; Zhu, Xinyong; Sun, Weiwen; Liu, Liu; Xu, En

    2014-10-01

    Hypoxia administered after transient global cerebral ischemia (tGCI) has been shown to induce neuroprotection in adult rats, but the underlying mechanisms for this protection are unclear. Here, we tested the hypothesis that hypoxic postconditioning (HPC) induces neuroprotection through upregulation of hypoxia-inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF), and that this involves phosphatidylinositol-3-kinase (PI3K), p38 mitogen-activated protein kinase (p38 MAPK), and mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK) pathways. The expression of HIF-1α, VEGF, and cleaved caspase-9 were determined by immunohistochemistry and Western blot. As pharmacologic interventions, the HIF-1α inhibitor 2-methoxyestradiol (2ME2), PI3K inhibitor LY294002, p38 MAPK inhibitor SB203580, and MEK inhibitor U0126 were administered before HPC or after tGCI. We found that HPC maintained the higher expression of HIF-1α and VEGF and decreased cleaved caspase-9 levels in CA1 after tGCI. These effects were reversed by 2ME2 administered before HPC, and the neuroprotection of HPC was abolished. LY294002 and SB203580 decreased the expression of HIF-1α and VEGF after HPC, whereas U0126 increased HIF-1α and VEGF after tGCI. These findings suggested that HIF-1α exerts neuroprotection induced by HPC against tGCI through VEGF upregulation and cleaved caspase-9 downregulation, and that the PI3K, p38 MAPK, and MEK pathways are involved in the regulation of HIF-1α and VEGF.

  1. Aspartyl-(asparaginyl β-Hydroxylase, Hypoxia-Inducible Factor-1α and Notch Cross-Talk in Regulating Neuronal Motility

    Directory of Open Access Journals (Sweden)

    Margot Lawton

    2010-01-01

    Full Text Available Aspartyl-(Asparaginyl-β-Hydroxylase (AAH promotes cell motility by hydroxylating Notch. Insulin and insulin-like growth factor, type 1 (IGF-I stimulate AAH through Erk MAP K and phosphoinositol-3-kinase-Akt (PI3K-Akt. However, hypoxia/oxidative stress may also regulate AAH . Hypoxia-inducible factor-1alpha (HIF-1α regulates cell migration, signals through Notch, and is regulated by hypoxia/oxidative stress, insulin/IGF signaling and factor inhibiting HIF-1α (FIH hydroxylation. To examine cross-talk between HIF-1α and AAH , we measured AAH , Notch-1, Jagged-1, FIH, HIF-1α, HIF-1β and the hairy and enhancer of split 1 (HE S-1 transcription factor expression and directional motility in primitive neuroectodermal tumor 2 (PNET2 human neuronal cells that were exposed to H2O2 or transfected with short interfering RNA duplexes (siRNA targeting AAH , Notch-1 or HIF-1α. We found that: (1 AAH , HIF-1α and neuronal migration were stimulated by H2O2; (2 si-HIF-1α reduced AAH expression and cell motility; (3 si-AAH inhibited Notch and cell migration, but not HIF-1α and (4 si-Notch-1 increased FIH and inhibited HIF-1α. These findings suggest that AAH and HIF-1α crosstalk within a hydroxylation-regulated signaling pathway that may be transiently driven by oxidative stress and chronically regulated by insulin/IGF signaling.

  2. Hypoxia-inducible factor-dependent production of profibrotic mediators by hypoxic hepatocytes.

    Science.gov (United States)

    Copple, Bryan L; Bustamante, Juan J; Welch, Timothy P; Kim, Nam Deuk; Moon, Jeon-Ok

    2009-08-01

    During the development of liver fibrosis, mediators are produced that stimulate cells in the liver to differentiate into myofibroblasts and to produce collagen. Recent studies demonstrated that the transcription factor, hypoxia-inducible factor-1alpha (HIF-1alpha), is critical for upregulation of profibrotic mediators, such as platelet-derived growth factor-A (PDGF-A), PDGF-B and plasminogen activator inhibitor-1 (PAI-1) in the liver, during the development of fibrosis. What remains unknown is the cell type-specific regulation of these genes by HIF-1alpha in liver cell types. Accordingly, the hypothesis was tested that HIF-1alpha is activated in hypoxic hepatocytes and regulates the production of profibrotic mediators by these cells. In this study, hepatocytes were isolated from the livers of control and HIF-1alpha- or HIF-1beta-deficient mice and exposed to hypoxia. Exposure of primary mouse hepatocytes to 1% oxygen stimulated nuclear accumulation of HIF-1alpha and upregulated PAI-1, vascular endothelial cell growth factor and the vasoactive peptides adrenomedullin-1 (ADM-1) and ADM-2. In contrast, the levels of PDGF-A and PDGF-B mRNAs were unaffected in these cells by hypoxia. Exposure of HIF-1alpha-deficient hepatocytes to 1% oxygen only partially prevented upregulation of these genes, suggesting that other hypoxia-regulated transcription factors, such as HIF-2alpha, may also regulate these genes. In support of this, HIF-2alpha was activated in hypoxic hepatocytes, and exposure of HIF-1beta-deficient hepatocytes to 1% oxygen completely prevented upregulation of PAI-1, vascular endothelial cell growth factor and ADM-1, suggesting that HIF-2alpha may also contribute to upregulation of these genes in hypoxic hepatocytes. Collectively, our results suggest that HIFs may be important regulators of profibrotic and vasoactive mediators by hypoxic hepatocytes.

  3. Targeting Hypoxia-Inducible Factor 1α in a New Orthotopic Model of Glioblastoma Recapitulating the Hypoxic Tumor Microenvironment.

    Science.gov (United States)

    Nigim, Fares; Cavanaugh, Jill; Patel, Anoop P; Curry, William T; Esaki, Shin-ichi; Kasper, Ekkehard M; Chi, Andrew S; Louis, David N; Martuza, Robert L; Rabkin, Samuel D; Wakimoto, Hiroaki

    2015-07-01

    Tissue hypoxia and necrosis represent pathophysiologic and histologic hallmarks of glioblastoma (GBM). Although hypoxia inducible factor 1α (HIF-1α) plays crucial roles in the malignant phenotypes of GBM, developing HIF-1α-targeted agents has been hampered by the lack of a suitable preclinical model that recapitulates the complex biology of clinical GBM. We present a new GBM model, MGG123, which was established from a recurrent human GBM. Orthotopic xenografting of stem-like MGG123 cells reproducibly generated lethal tumors that were characterized by foci of palisading necrosis, hypervascularity, and robust stem cell marker expression. Perinecrotic neoplastic cells distinctively express HIF-1α and are proliferative in both xenografts and the patient tissue. The xenografts contain scattered hypoxic foci that were consistently greater than 50 μm distant from blood vessels, indicating intratumoral heterogeneity of oxygenation. Hypoxia enhanced HIF-1α expression in cultured MGG123 cells, which was abrogated by the HIF-1α inhibitors digoxin or ouabain. In vivo, treatment of orthotopic MGG123 xenografts with digoxin decreased HIF-1α expression, vascular endothelial growth factor mRNA levels, and CD34-positive vasculature within the tumors, and extended survival of mice bearing the aggressive MGG123 GBM. This preclinical tumor model faithfully recapitulates the GBM-relevant hypoxic microenvironment and stemness and is a suitable platform for studying disease biology and developing hypoxia-targeted agents.

  4. Enzyme 15-lipoxygenase 1 promotes hypoxia-inducible factor 1α turnover and reduces vascular endothelial growth factor expression: implications for angiogenesis

    International Nuclear Information System (INIS)

    Zhong, Hua; Wang, Ruoxiang; Kelavkar, Uddhav; Wang, Christopher Y; Simons, Jonathan

    2014-01-01

    Hypoxia-inducible factor 1α (HIF-1α) is the regulatory subunit of the heterodimeric HIF-1 that plays a critical role in transcriptional regulation of genes in angiogenesis and hypoxic adaptation, while fatty acid metabolism mediated by lipoxygenases has been implicated in a variety of pathogeneses, including cancers. In this study, we report that 15-lipoxygenase 1 (15-LO1), a key member of the lipoxygenase family, promotes HIF-1α ubiquitination and degradation. Altering the level of 15-LO1 yields inverse changes in HIF-1α and HIF-1 transcriptional activity, under both normoxia and hypoxia, and even in CoCl 2 -treated cells where HIF-1α has been artificially elevated. The antagonistic effect of 15-LO1 is mediated by the Pro 564 /hydroxylation/26S proteasome system, while both the enzymatic activity and the intracellular membrane-binding function of 15-LO1 appear to contribute to HIF-1α suppression. Our findings provide a novel mechanism for HIF-1α regulation, in which oxygen-dependent HIF-1 activity is modulated by an oxygen-insensitive lipid metabolic enzyme

  5. Fentanyl activates hypoxia-inducible factor 1 in neuronal SH-SY5Y cells and mice under non-hypoxic conditions in a μ-opioid receptor-dependent manner.

    Science.gov (United States)

    Daijo, Hiroki; Kai, Shinichi; Tanaka, Tomoharu; Wakamatsu, Takuhiko; Kishimoto, Shun; Suzuki, Kengo; Harada, Hiroshi; Takabuchi, Satoshi; Adachi, Takehiko; Fukuda, Kazuhiko; Hirota, Kiichi

    2011-09-30

    Hypoxia-inducible factor 1 (HIF-1) is the main transcription factor responsible for hypoxia-induced gene expression. Perioperative drugs including anesthetics have been reported to affect HIF-1 activity. However, the effect of fentanyl on HIF-1 activity is not well documented. In this study, we investigated the effect of fentanyl and other opioids on HIF-1 activity in human SH-SY5Y neuroblastoma cells, hepatoma Hep3B cells, lung adenocarcinoma A549 cells and mice. Cells were exposed to fentanyl, and HIF-1 protein expression was examined by Western blot analysis using anti-HIF-1α and β antibodies. HIF-1-dependent gene expression was investigated by semi-quantitative real-time reverse transcriptase (RT)-PCR (qRT-PCR) and luciferase assay. Furthermore, fentanyl was administered intraperitoneally and HIF-1-dependent gene expression was investigated by qRT-PCR in the brains and kidneys of mice. A 10-μM concentration of fentanyl and other opioids, including 1 μM morphine and 4 μM remifentanil, induced HIF-1α protein expression and HIF-1 target gene expression in an opioid receptor-dependent manner in SH-SY5Y cells with activity peaking at 24h. Fentanyl did not augment HIF-1α expression during hypoxia-induced induction. HIF-1α stabilization assays and experiments with cycloheximide revealed that fentanyl increased translation from HIF-1α mRNA but did not stabilize the HIF-1α protein. Furthermore, fentanyl induced HIF-1 target gene expression in the brains of mice but not in their kidneys in a naloxone-sensitive manner. In this report, we describe for the first time that fentanyl, both in vitro and in vivo, induces HIF-1 activation under non-hypoxic conditions, leading to increases in expression of genes associated with adaptation to hypoxia. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Overexpression of ERβ is sufficient to inhibit hypoxia-inducible factor-1 transactivation

    International Nuclear Information System (INIS)

    Park, Choa; Lee, YoungJoo

    2014-01-01

    Highlights: • We examined the effect of ERβ specific ligand on HIF-1 inhibition. • DPN down-regulates the ARNT protein levels in PC3 cells. • DPN did not show additional effect in ERβ transfected MCF-7 cells. • Our study shows that unliganded ERβ is sufficient to inhibit HIF-1 in systems of overexpression. - Abstract: Estrogen receptor (ER) β is predicted to play an important role in the prevention of breast cancer development and progression. We have previously shown that ERβ suppresses hypoxia inducible factor (HIF)-1-mediated transcription through aryl hydrocarbon receptor nuclear translocator (ARNT) degradation via ubiquitination processes. In this study, we attempted to examine the effect of ERβ specific ligand on HIF-1 inhibition in ERβ positive PC3 cells and ERβ transfected MCF-7 cells. ERβ specific agonist diarylpropionitrile (DPN) stimulated estrogen response element (ERE)-luciferase activity in a similar fashion to estradiol in PC3 cells. We observed that DPN down-regulates the ARNT protein levels leading to an attenuation of hypoxia-induced hypoxia response element (HRE)-driven luciferase reporter gene activation in PC3 cells. Treatment of DPN reduced vascular endothelial growth factor (VEGF) expression and co-treatment with ERβ specific antagonist PHTPP abrogated the effect in PC3 cells. We then examined the effect of DPN in ERβ transfected MCF-7 cells. HIF-1 transcriptional activity repression by ERβ was not further reduced by DPN, as examined by HRE-driven luciferase assays. Expression of ERβ significantly decreased VEGF secretion and ARNT expression under hypoxic conditions. However, DPN did not additionally affect this suppression in MCF-7 cells transfected with ERβ. This result shows that unliganded ERβ is sufficient to inhibit HIF-1 in systems of overexpression

  7. Overexpression of ERβ is sufficient to inhibit hypoxia-inducible factor-1 transactivation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Choa; Lee, YoungJoo, E-mail: yjlee@sejong.ac.kr

    2014-07-18

    Highlights: • We examined the effect of ERβ specific ligand on HIF-1 inhibition. • DPN down-regulates the ARNT protein levels in PC3 cells. • DPN did not show additional effect in ERβ transfected MCF-7 cells. • Our study shows that unliganded ERβ is sufficient to inhibit HIF-1 in systems of overexpression. - Abstract: Estrogen receptor (ER) β is predicted to play an important role in the prevention of breast cancer development and progression. We have previously shown that ERβ suppresses hypoxia inducible factor (HIF)-1-mediated transcription through aryl hydrocarbon receptor nuclear translocator (ARNT) degradation via ubiquitination processes. In this study, we attempted to examine the effect of ERβ specific ligand on HIF-1 inhibition in ERβ positive PC3 cells and ERβ transfected MCF-7 cells. ERβ specific agonist diarylpropionitrile (DPN) stimulated estrogen response element (ERE)-luciferase activity in a similar fashion to estradiol in PC3 cells. We observed that DPN down-regulates the ARNT protein levels leading to an attenuation of hypoxia-induced hypoxia response element (HRE)-driven luciferase reporter gene activation in PC3 cells. Treatment of DPN reduced vascular endothelial growth factor (VEGF) expression and co-treatment with ERβ specific antagonist PHTPP abrogated the effect in PC3 cells. We then examined the effect of DPN in ERβ transfected MCF-7 cells. HIF-1 transcriptional activity repression by ERβ was not further reduced by DPN, as examined by HRE-driven luciferase assays. Expression of ERβ significantly decreased VEGF secretion and ARNT expression under hypoxic conditions. However, DPN did not additionally affect this suppression in MCF-7 cells transfected with ERβ. This result shows that unliganded ERβ is sufficient to inhibit HIF-1 in systems of overexpression.

  8. Silver nanoparticles inhibit the function of hypoxia-inducible factor-1 and target genes: insight into the cytotoxicity and antiangiogenesis

    Directory of Open Access Journals (Sweden)

    Yang T

    2016-12-01

    Full Text Available Tieshan Yang,1 Qian Yao,1 Fei Cao,1 Qianqian Liu,1 Binlei Liu,2 Xiu-Hong Wang1 1Laboratory for Biomedical Photonics, Institute of Laser Engineering, Beijing University of Technology, 2Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of China Abstract: Hypoxia-inducible factor-1 (HIF-1 is a transcription factor that is activated upon exposure to hypoxic stress. It modulates a number of cellular responses including proliferation, apoptosis, angiogenesis, and metabolism by activating a panel of target genes in response to hypoxia. The HIF-1 level is often upregulated in the hypoxic microenvironment of solid tumors, which contributes to cancer treatment failure. Here we report that silver nanoparticles (AgNPs, which are widely used as an antimicrobial agent, are an effective inhibitor of HIF-1. AgNPs inhibited the activation of a HIF-dependent reporter construct after the cells were exposed to hypoxic conditions or treated with cobalt chloride, a hypoxia mimetic agent. The AgNPs also interfered with the accumulation of HIF-1α protein and the induction of the endogenous HIF target genes, VEGF-A and GLUT1. Since both HIF-1 and vascular endothelial growth factor-A play an important role in angiogenesis, AgNPs also inhibited angiogenesis in vitro. Our data reveal a new mechanism of how AgNPs act on cellular function, that is, they disrupt HIF signaling pathway. This finding provides a novel insight into how AgNPs can inhibit cancer cell growth and angiogenesis. Keywords: silver nanoparticles (AgNPs, hypoxia-inducible factor, transcriptional activity, vascular endothelial growth factor-A, angiogenesis

  9. Differential roles of Sirt1 in HIF-1α and HIF-2α mediated hypoxic responses

    International Nuclear Information System (INIS)

    Yoon, Haejin; Shin, Seung-Hyun; Shin, Dong Hoon; Chun, Yang-Sook; Park, Jong-Wan

    2014-01-01

    Highlights: • Roles of SIRT1 in HIF-1α and HIF-2α regulations are reevaluated using specific antibodies and Gal4 reporters. • SIRT1 represses the HIF-1α-driven transcription constantly in ten cancer cell-lines. • SIRT1 regulates the HIF-2α-driven transcription cell context-dependently. • SIRT1 determines cell growth under hypoxia by regulating HIF-1α and HIF-2α activities. - Abstract: Hypoxia-inducible factors 1α and 2α (HIF-1α and HIF-2α) determine cancer cell fate under hypoxia. Despite the similarities of their structures, HIF-1α and HIF-2α have distinct roles in cancer growth under hypoxia, that is, HIF-1α induces growth arrest whereas HIF-2α promotes cell growth. Recently, sirtuin 1 (Sirt1) was reported to fine-tune cellular responses to hypoxia by deacetylating HIF-1α and HIF-2α. Yet, the roles of Sirt1 in HIF-1α and HIF-2α functions have been controversial. We here investigated the precise roles of Sirt1 in HIF-1α and HIF-2α regulations. Immunological analyses revealed that HIF-1α K674 and HIF-2α K741 are acetylated by PCAF and CBP, respectively, but are deacetylated commonly by Sirt1. In the Gal4 reporter systems, Sirt1 was found to repress HIF-1α activity constantly in ten cancer cell-lines but to regulate HIF-2α activity cell type-dependently. Moreover, Sirt1 determined cell growth under hypoxia depending on HIF-1α and HIF-2α. Under hypoxia, Sirt1 promoted cell proliferation of HepG2, in which Sirt1 differentially regulates HIF-1α and HIF-2α. In contrast, such an effect of Sirt1 was not shown in HCT116, in which Sirt1 inactivates both HIF-1α and HIF-2α because conflicting actions of HIF-1α and HIF-2α on cell growth may be offset. Our results provide a better understanding of the roles of Sirt1 in HIF-mediated hypoxic responses and also a basic concept for developing anticancer strategy targeting Sirt1

  10. Hepatocyte Hypoxia Inducible Factor-1 Mediates the Development of Liver Fibrosis in a Mouse Model of Nonalcoholic Fatty Liver Disease.

    Directory of Open Access Journals (Sweden)

    Omar A Mesarwi

    Full Text Available Obstructive sleep apnea (OSA is associated with the progression of non-alcoholic fatty liver disease (NAFLD to steatohepatitis and fibrosis. This progression correlates with the severity of OSA-associated hypoxia. In mice with diet induced obesity, hepatic steatosis leads to liver tissue hypoxia, which worsens with exposure to intermittent hypoxia. Emerging data has implicated hepatocyte cell signaling as an important factor in hepatic fibrogenesis. We hypothesized that hepatocyte specific knockout of the oxygen sensing α subunit of hypoxia inducible factor-1 (HIF-1, a master regulator of the global response to hypoxia, may be protective against the development of liver fibrosis.Wild-type mice and mice with hepatocyte-specific HIF-1α knockout (Hif1a-/-hep were fed a high trans-fat diet for six months, as a model of NAFLD. Hepatic fibrosis was evaluated by Sirius red stain and hydroxyproline assay. Liver enzymes, fasting insulin, and hepatic triglyceride content were also assessed. Hepatocytes were isolated from Hif1a-/-hep mice and wild-type controls and were exposed to sustained hypoxia (1% O2 or normoxia (16% O2 for 24 hours. The culture media was used to reconstitute type I collagen and the resulting matrices were examined for collagen cross-linking.Wild-type mice on a high trans-fat diet had 80% more hepatic collagen than Hif1a-/-hep mice (2.21 μg collagen/mg liver tissue, versus 1.23 μg collagen/mg liver tissue, p = 0.03, which was confirmed by Sirius red staining. Body weight, liver weight, mean hepatic triglyceride content, and fasting insulin were similar between groups. Culture media from wild-type mouse hepatocytes exposed to hypoxia allowed for avid collagen cross-linking, but very little cross-linking was seen when hepatocytes were exposed to normoxia, or when hepatocytes from Hif1a-/-hep mice were used in hypoxia or normoxia.Hepatocyte HIF-1 mediates an increase in liver fibrosis in a mouse model of NAFLD, perhaps due to liver

  11. Hypoxia-Inducible Factor-1 in Physiological and Pathophysiological Angiogenesis: Applications and Therapies

    Science.gov (United States)

    Zimna, Agnieszka; Kurpisz, Maciej

    2015-01-01

    The cardiovascular system ensures the delivery of oxygen and nutrients to all cells, tissues, and organs. Under extended exposure to reduced oxygen levels, cells are able to survive through the transcriptional activation of a series of genes that participate in angiogenesis, glucose metabolism, and cell proliferation. The oxygen-sensitive transcriptional activator HIF-1 (hypoxia-inducible factor-1) is a key transcriptional mediator of the response to hypoxic conditions. The HIF-1 pathway was found to be a master regulator of angiogenesis. Whether the process is physiological or pathological, HIF-1 seems to participate in vasculature formation by synergistic correlations with other proangiogenic factors such as VEGF (vascular endothelial growth factor), PlGF (placental growth factor), or angiopoietins. Considering the important contributions of HIF-1 in angiogenesis and vasculogenesis, it should be considered a promising target for treating ischaemic diseases or cancer. In this review, we discuss the roles of HIF-1 in both physiological/pathophysiological angiogenesis and potential strategies for clinical therapy. PMID:26146622

  12. Epidermal growth factor receptor inhibition reduces angiogenesis via hypoxia-inducible factor-1α and Notch1 in head neck squamous cell carcinoma.

    Directory of Open Access Journals (Sweden)

    Wei-Ming Wang

    Full Text Available Angiogenesis, a marker of cancer development, affects response to radiotherapy sensibility. This preclinical study aims to understand the receptor tyrosine kinase-mediated angiogenesis in head neck squamous cell carcinoma (HNSCC. The receptor tyrosine kinase activity in a transgenic mouse model of HNSCC was assessed. The anti-tumorigenetic and anti-angiogenetic effects of cetuximab-induced epidermal growth factor receptor (EGFR inhibition were investigated in xenograft and transgenic mouse models of HNSCC. The signaling transduction of Notch1 and hypoxia-inducible factor-1α (HIF-1α was also analyzed. EGFR was overexpressed and activated in the Tgfbr1/Pten deletion (2cKO mouse model of HNSCC. Cetuximab significantly delayed tumor onset by reducing tumor angiogenesis. This drug exerted similar effects on heterotopic xenograft tumors. In the human HNSCC tissue array, increased EGFR expression correlated with increased HIF-1α and micro vessel density. Cetuximab inhibited tumor-induced angiogenesis in vitro and in vivo by significantly downregulating HIF-1α and Notch1. EGFR is involved in the tumor angiogenesis of HNSCC via the HIF-1α and Notch1 pathways. Therefore, targeting EGFR by suppressing hypoxia- and Notch-induced angiogenesis may benefit HNSCC therapy.

  13. Nuclear factor-κB-dependent epithelial to mesenchymal transition induced by HIF-1α activation in pancreatic cancer cells under hypoxic conditions.

    Directory of Open Access Journals (Sweden)

    Zhuo-Xin Cheng

    Full Text Available Epithelial to mesenchymal transition (EMT induced by hypoxia is one of the critical causes of treatment failure in different types of human cancers. NF-κB is closely involved in the progression of EMT. Compared with HIF-1α, the correlation between NF-κB and EMT during hypoxia has been less studied, and although the phenomenon was observed in the past, the molecular mechanisms involved remained unclear.Here, we report that hypoxia or overexpression of hypoxia-inducible factor-1α (HIF-1α promotes EMT in pancreatic cancer cells. On molecular or pharmacologic inhibition of NF-κB, hypoxic cells regained expression of E-cadherin, lost expression of N-cadherin, and attenuated their highly invasive and drug-resistant phenotype. Introducing a pcDNA3.0/HIF-1α into pancreatic cancer cells under normoxic conditions heightened NF-κB activity, phenocopying EMT effects produced by hypoxia. Conversely, inhibiting the heightened NF-κB activity in this setting attenuated the EMT phenotype.These results suggest that hypoxia or overexpression of HIF-1α induces the EMT that is largely dependent on NF-κB in pancreatic cancer cells.

  14. Unilateral Partial Nephrectomy with Warm Ischemia Results in Acute Hypoxia Inducible Factor 1-Alpha (HIF-1α and Toll-Like Receptor 4 (TLR4 Overexpression in a Porcine Model.

    Directory of Open Access Journals (Sweden)

    Zhiyong Zhang

    Full Text Available Ischemia/reperfusion (I/R during partial nephrectomy (PN contributes to acute kidney injury (AKI, which is inaccurately assessed using existent clinical markers of renal function. We evaluated I/R-related changes in expression in hypoxia inducible factor 1α (HIF-1α and toll-like receptor 4 (TLR4, within kidney tissue and peripheral blood leukocytes (PBL in a porcine model of PN.Three adult pigs each underwent unilateral renal hilar cross clamping for 180 min followed by a 15 min reperfusion. The contralateral kidney served as control. Biopsies of clamped kidneys were obtained at baseline (time 0, every 60 min during the hypoxic phase, and post-reperfusion. Control kidneys were biopsied once at 180 min. Peripheral blood was sampled at time 0, every 30 min during the hypoxic phase, and post-reperfusion. HIF-1α and TLR4 expression in kidney tissue and PBL were analyzed by Western blotting. I/R-related histological changes were assessed.Expression of HIF-1α in clamped kidneys and PBL was below detection level at baseline, rising to detectable levels after 60 min of hypoxia, and continuing to rise throughout the hypoxic and reperfusion phases. Expression of TLR-4 in clamped kidneys followed a similar trend with initial detection after 30-60 min of hypoxia. Control kidneys exhibited no change in HIF-1α or TLR-4 expression. I/R-related histologic changes were minimal, primarily mild tubular dilatation.In a porcine model of PN, HIF-1α and TLR4 exhibited robust, I/R-related increases in expression in kidney tissue and PBL. Further studies investigating these molecules as potential markers of AKI are warranted.

  15. Ubiquitination is absolutely required for the degradation of hypoxia-inducible factor - 1 alpha protein in hypoxic conditions

    International Nuclear Information System (INIS)

    Wang, Ronghai; Zhang, Ping; Li, Jinhang; Guan, Hongzai; Shi, Guangjun

    2016-01-01

    The hypoxia-inducible factor (HIF) is recognized as the master regulator of hypoxia response. HIF-α subunits expression are tightly regulated. In this study, our data show that ts20 cells still expressed detectable E1 protein even at 39.5° C for 12 h, and complete depletion of E1 protein expression at 39.5° C by siRNA enhanced HIF-1α and P53 protein expression. Further inhibition of E1 at 39.5 °C by siRNA, or E1 inhibitor Ube1-41 completely blocked HIF-1α degradation. Moreover, immunoprecipitations of co-transfection of HA-ubiquitin and FLAG–HIF–1α plasmids directly confirmed the involvement of ubiquitin in the hypoxic degradation of HIF-1α. Additionally, hypoxic HIF-1 α degradation is independent of HAF, RACK1, sumoylation or nuclear/cytoplasmic localization. Taken together, our data suggest that constitutive HIF-1α protein degradation in hypoxia is absolutely ubiquitination-dependent, and unidentified E3 ligase may exist for this degradation pathway. - Highlights: • HIF-1α protein is constitutively degraded in hypoxic conditions. • Requirement of ubiquitination for HIF-1α degradation in hypoxia. • Hypoxic HIF-1α degradation is independent of HAF, RACK1, sumoylation or nuclear/cytoplasmic localization.

  16. Ubiquitination is absolutely required for the degradation of hypoxia-inducible factor - 1 alpha protein in hypoxic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ronghai [Department of Urology, Linzi District People' s Hospital, Zibo, 255400 (China); Zhang, Ping, E-mail: zpskx001@163.com [Department of Gynecology, Qingdao Municipal Hospital, Qingdao, 266011 (China); Li, Jinhang [Department of Gynecology, Qingdao Municipal Hospital, Qingdao, 266011 (China); Guan, Hongzai [Laboratory Department, School of Medicine, Qingdao University, Qingdao, 266071 (China); Shi, Guangjun, E-mail: qdmhshigj@yahoo.com [Department of Hepatobiliary Surgery, Qingdao Municipal Hospital, Qingdao, 266071 (China)

    2016-01-29

    The hypoxia-inducible factor (HIF) is recognized as the master regulator of hypoxia response. HIF-α subunits expression are tightly regulated. In this study, our data show that ts20 cells still expressed detectable E1 protein even at 39.5° C for 12 h, and complete depletion of E1 protein expression at 39.5° C by siRNA enhanced HIF-1α and P53 protein expression. Further inhibition of E1 at 39.5 °C by siRNA, or E1 inhibitor Ube1-41 completely blocked HIF-1α degradation. Moreover, immunoprecipitations of co-transfection of HA-ubiquitin and FLAG–HIF–1α plasmids directly confirmed the involvement of ubiquitin in the hypoxic degradation of HIF-1α. Additionally, hypoxic HIF-1 α degradation is independent of HAF, RACK1, sumoylation or nuclear/cytoplasmic localization. Taken together, our data suggest that constitutive HIF-1α protein degradation in hypoxia is absolutely ubiquitination-dependent, and unidentified E3 ligase may exist for this degradation pathway. - Highlights: • HIF-1α protein is constitutively degraded in hypoxic conditions. • Requirement of ubiquitination for HIF-1α degradation in hypoxia. • Hypoxic HIF-1α degradation is independent of HAF, RACK1, sumoylation or nuclear/cytoplasmic localization.

  17. The redox protein thioredoxin-1 (Trx-1) increases hypoxia-inducible factor 1alpha protein expression: Trx-1 overexpression results in increased vascular endothelial growth factor production and enhanced tumor angiogenesis.

    Science.gov (United States)

    Welsh, Sarah J; Bellamy, William T; Briehl, Margaret M; Powis, Garth

    2002-09-01

    Hypoxia-inducible factor 1 (HIF-1), a heterodimer of HIF-1alpha and HIF-1beta subunits, is a transcriptional activator central to the cellular response to low oxygen that includes metabolic adaptation, angiogenesis, metastasis, and inhibited apoptosis. Thioredoxin-1 (Trx-1) is a small redox protein overexpressed in a number of human primary tumors. We have examined the effects of Trx-1 on HIF activity and the activation of downstream genes. Stable transfection of human breast carcinoma MCF-7 cells with human Trx-1 caused a significant increase in HIF-1alpha protein levels under both normoxic (20% oxygen) and hypoxic (1% oxygen) conditions. Trx-1 increased hypoxia-induced HIF-1 transactivation activity measured using a luciferase reporter under the control of the hypoxia response element. Changes in HIF-1alpha mRNA levels did not account for the changes observed at the protein level, and HIF-1beta protein levels did not change. Trx-1 transfection also caused a significant increase in the protein products of hypoxia-responsive genes, including vascular endothelial growth factor (VEGF) and nitric oxide synthase 2 in a number of different cell lines (MCF-7 human breast and HT29 human colon carcinomas and WEHI7.2 mouse lymphoma cells) under both normoxic and hypoxic conditions. The pattern of expression of the different isoforms of VEGF was not changed by Trx-1. Transfection of a redox-inactive Trx-1 (C32S/C35S) markedly decreased levels of HIF-1alpha protein, HIF-1 transactivating activity, and VEGF protein in MCF-7 cells compared with empty vector controls. In vivo studies using WEHI7.2 cells transfected with Trx-1 showed significantly increased tumor VEGF and angiogenesis. The results suggest that Trx-1 increases HIF-1alpha protein levels in cancer cells and increases VEGF production and tumor angiogenesis.

  18. Survival of hypoxic human mesenchymal stem cells is enhanced by a positive feedback loop involving miR-210 and hypoxia-inducible factor 1.

    Science.gov (United States)

    Chang, Woochul; Lee, Chang Youn; Park, Jun-Hee; Park, Moon-Seo; Maeng, Lee-So; Yoon, Chee Soon; Lee, Min Young; Hwang, Ki-Chul; Chung, Yong-An

    2013-01-01

    The use of mesenchymal stem cells (MSCs) has emerged as a potential new treatment for myocardial infarction. However, the poor viability of MSCs after transplantation critically limits the efficacy of this new strategy. The expression of microRNA-210 (miR-210) is induced by hypoxia and is important for cell survival under hypoxic conditions. Hypoxia increases the levels of hypoxia inducible factor-1 (HIF-1) protein and miR-210 in human MSCs (hMSCs). miR-210 positively regulates HIF-1α activity. Furthermore, miR-210 expression is also induced by hypoxia through the regulation of HIF-1α. To investigate the effect of miR-210 on hMSC survival under hypoxic conditions, survival rates along with signaling related to cell survival were evaluated in hMSCs over-expressing miR-210 or ones that lacked HIF-1α expression. Elevated miR-210 expression increased survival rates along with Akt and ERK activity in hMSCs with hypoxia. These data demonstrated that a positive feedback loop involving miR-210 and HIF-1α was important for MSC survival under hypoxic conditions.

  19. Radiolabeled Probes Targeting Hypoxia-Inducible Factor-1-Active Tumor Microenvironments

    Directory of Open Access Journals (Sweden)

    Masashi Ueda

    2014-01-01

    Full Text Available Because tumor cells grow rapidly and randomly, hypoxic regions arise from the lack of oxygen supply in solid tumors. Hypoxic regions in tumors are known to be resistant to chemotherapy and radiotherapy. Hypoxia-inducible factor-1 (HIF-1 expressed in hypoxic regions regulates the expression of genes related to tumor growth, angiogenesis, metastasis, and therapy resistance. Thus, imaging of HIF-1-active regions in tumors is of great interest. HIF-1 activity is regulated by the expression and degradation of its α subunit (HIF-1α, which is degraded in the proteasome under normoxic conditions, but escapes degradation under hypoxic conditions, allowing it to activate transcription of HIF-1-target genes. Therefore, to image HIF-1-active regions, HIF-1-dependent reporter systems and injectable probes that are degraded in a manner similar to HIF-1α have been recently developed and used in preclinical studies. However, no probe currently used in clinical practice directly assesses HIF-1 activity. Whether the accumulation of 18F-FDG or 18F-FMISO can be utilized as an index of HIF-1 activity has been investigated in clinical studies. In this review, the current status of HIF-1 imaging in preclinical and clinical studies is discussed.

  20. The role of hypoxia-inducible factor-2 in digestive system cancers.

    Science.gov (United States)

    Zhao, J; Du, F; Shen, G; Zheng, F; Xu, B

    2015-01-15

    Hypoxia is an all but ubiquitous phenomenon in cancers. Two known hypoxia-inducible factors (HIFs), HIF-1α and HIF-2α, primarily mediate the transcriptional response to hypoxia. Despite the high homology between HIF-1α and HIF-2α, emerging evidence suggests differences between both molecules in terms of transcriptional targets as well as impact on multiple physiological pathways and tumorigenesis. To date, much progress has been made toward understanding the roles of HIF-2α in digestive system cancers. Indeed, HIF-2α has been shown to regulate multiple aspects of digestive system cancers, including cell proliferation, angiogenesis and apoptosis, metabolism, metastasis and resistance to chemotherapy. These findings make HIF-2α a critical regulator of this malignant phenotype. Here we summarize the function of HIF-2 during cancer development as well as its contribution to tumorigenesis in digestive system malignancies.

  1. [Research progress of mechanism of hypoxia-inducible factor-1α signaling pathway in condylar cartilage growth and remodeling].

    Science.gov (United States)

    Gaoli, Xu; Lili, Wu; Zhiwu, Wu; Zhiyuan, Gu

    2016-12-01

    The condylar cartilage was adapted to hypoxic conditions in vivo. However, condylar cartilage cells exposed in normoxia in vitro affect the chondrocyte phenotype and cartilage matrix formation. This condition also resulted in great difficulty in chondrocyte research. Culturing chondrocyte should be simulated in in vivo hypoxia environment as much as possible. The hypoxia-inducible factor-1α (HIF-1α) demonstrates an important transcription factor of adaptive response to hypoxic conditions. HIF-1α also plays an active role in maintaining homeostasis and function of chondrocytes. This review summarized current knowledge of the HIF-1α structure, signaling pathway, and mechanism of HIF-1α in the condylar cartilage repair.

  2. High frequency of HIF-1 alpha overexpression in BRCA1 related breast cancer

    NARCIS (Netherlands)

    van der Groep, Petra; Bouter, Alwin; Menko, Fred H.; van der Wall, Elsken; van Diest, Paul J.

    2008-01-01

    Hypoxia is a hallmark of cancer. Hypoxia inducible factor-1 alpha (HIF-1 alpha) is the key regulator of the hypoxia response. HIF-1 alpha is overexpressed during sporadic breast carcinogenesis and correlated with poor prognosis. Little is known on the role of HIF-1 alpha in hereditary breast

  3. Hypoxia Inducible Factors and Hypertension: Lessons from Sleep Apnea Syndrome

    Science.gov (United States)

    Nanduri, Jayasri; Peng, Ying-Jie; Yuan, Guoxiang; Kumar, Ganesh K.; Prabhakar, Nanduri R.

    2015-01-01

    Systemic hypertension is one of the most prevalent cardiovascular diseases. Sleep disordered breathing (SDB) with recurrent apnea is a major risk factor for developing essential hypertension. Chronic intermittent hypoxia (CIH) is a hallmark manifestation of recurrent apnea. Rodent models patterned after the O2 profiles seen with SDB patients showed that CIH is the major stimulus for causing systemic hypertension. This article reviews the physiological and molecular basis of CIH-induced hypertension. Physiological studies have identified that augmented carotid body chemosensory reflex and the resulting increase in sympathetic nerve activity is a major contributor to CIH-induced hypertension. Analysis of molecular mechanisms revealed that CIH activates hypoxia-inducible factor (HIF)-1 and suppresses HIF-2- mediated transcription. Dysregulation of HIF-1- and HIF-2- mediated transcription leads to imbalance of pro-oxidant and anti-oxidant enzyme gene expression resulting in increased reactive species (ROS) generation in the chemosensory reflex which is central for developing hypertension. PMID:25772710

  4. Ubiquitination is absolutely required for the degradation of hypoxia-inducible factor--1 alpha protein in hypoxic conditions.

    Science.gov (United States)

    Wang, Ronghai; Zhang, Ping; Li, Jinhang; Guan, Hongzai; Shi, Guangjun

    2016-01-29

    The hypoxia-inducible factor (HIF) is recognized as the master regulator of hypoxia response. HIF-α subunits expression are tightly regulated. In this study, our data show that ts20 cells still expressed detectable E1 protein even at 39.5° C for 12 h, and complete depletion of E1 protein expression at 39.5° C by siRNA enhanced HIF-1α and P53 protein expression. Further inhibition of E1 at 39.5 °C by siRNA, or E1 inhibitor Ube1-41 completely blocked HIF-1α degradation. Moreover, immunoprecipitations of co-transfection of HA-ubiquitin and FLAG-HIF-1α plasmids directly confirmed the involvement of ubiquitin in the hypoxic degradation of HIF-1α. Additionally, hypoxic HIF-1 α degradation is independent of HAF, RACK1, sumoylation or nuclear/cytoplasmic localization. Taken together, our data suggest that constitutive HIF-1α protein degradation in hypoxia is absolutely ubiquitination-dependent, and unidentified E3 ligase may exist for this degradation pathway. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. HIF-1 α as a Key Factor in Bile Duct Ligation-Induced Liver Fibrosis in Rats.

    Science.gov (United States)

    Moczydlowska, Joanna; Miltyk, Wojciech; Hermanowicz, Adam; Lebensztejn, Dariusz M; Palka, Jerzy A; Debek, Wojciech

    2017-02-01

    Although several studies suggested hypoxia as an important microenvironmental factor contributing to inflammation and fibrosis in chronic liver diseases, the mechanism of this process is not fully understood. We considered hypoxia inducible factor (HIF-1α) as a key transcription factor in liver fibrosis. The aim of the study was to evaluate the mechanisms of signaling pathway during bile duct ligation (BDL)-induced liver fibrosis in rats. BDL animal model of liver fibrosis was used in the study. Male Wistar rats were divided randomly into two experimental groups: sham group (n = 15), BDL group (n = 30). Hydroxyproline (Hyp) content as a marker of collagen accumulation in liver of rats subjected to BDL was evaluated according to the method described by Gerling B et al. Expression of signaling proteins [integrin β 1 receptor, HIF-1α, nuclear factor kappa B (NF-κB), and transforming growth factor (TGF-β)] was evaluated applying Western-immunoblot analysis. In all experiments, the mean values for six assays ± standard deviations (SD) were calculated. The results were submitted to the statistical analysis using the Student's "t" test, accepting p bile ducts was found to increase Hyp content in rat liver, accompanied by increase of HIF-1α expression during 10 weeks after BDL. The Hyp level was time dependent. There was not such a difference in control group (p livers were increased 1 week after surgery and remained increased until the end of the experiment. The mechanism of development of liver fibrosis involves activation of Matrix metalloproteinase-2 (MMP-2) and Matrix metalloproteinase-9 (MMP-9), upregulation of HIF-1α transcriptional activity and its related factors, NF-κB and TGF-β. It suggests that they may represent targets for the treatment of the disease.

  6. Fatty Acid Uptake and Lipid Storage Induced by HIF-1α Contribute to Cell Growth and Survival after Hypoxia-Reoxygenation

    Directory of Open Access Journals (Sweden)

    Karim Bensaad

    2014-10-01

    Full Text Available Summary: An in vivo model of antiangiogenic therapy allowed us to identify genes upregulated by bevacizumab treatment, including Fatty Acid Binding Protein 3 (FABP3 and FABP7, both of which are involved in fatty acid uptake. In vitro, both were induced by hypoxia in a hypoxia-inducible factor-1α (HIF-1α-dependent manner. There was a significant lipid droplet (LD accumulation in hypoxia that was time and O2 concentration dependent. Knockdown of endogenous expression of FABP3, FABP7, or Adipophilin (an essential LD structural component significantly impaired LD formation under hypoxia. We showed that LD accumulation is due to FABP3/7-dependent fatty acid uptake while de novo fatty acid synthesis is repressed in hypoxia. We also showed that ATP production occurs via β-oxidation or glycogen degradation in a cell-type-dependent manner in hypoxia-reoxygenation. Finally, inhibition of lipid storage reduced protection against reactive oxygen species toxicity, decreased the survival of cells subjected to hypoxia-reoxygenation in vitro, and strongly impaired tumorigenesis in vivo. : Bensaad et al. now show that FABP3 and FABP7 are induced by HIF-1α and lead to a significant lipid droplet (LD accumulation in hypoxia. In hypoxia-reoxygenation, ATP production occurs via fatty acid β-oxidation or glycogen degradation in a cell-type-dependent manner, while inhibition of LD formation increases ROS toxicity and decreases cell survival in vitro and strongly impairs tumorigenesis in vivo.

  7. Role of hypoxia inducing factor-1β in alcohol-induced autophagy, steatosis and liver injury in mice.

    Directory of Open Access Journals (Sweden)

    Hong-Min Ni

    Full Text Available Chronic alcohol causes liver hypoxia and steatosis, which eventually develops into alcoholic liver disease (ALD. While it has been known that alcohol consumption activates hepatic hypoxia inducing factor-1α (HIF-1α, conflicting results regarding the role of HIF-1α in alcohol-induced liver injury and steatosis in mice have been reported. In the present study, we aimed to use hepatocyte-specific HIF-1β knockout mice to eliminate the possible compensatory effects of the single knockout of the 1α subunit of HIF to study the role of HIFs in ALD. C57BL/6 wild type mice were treated with acute ethanol to mimic human binge drinking. Matched wild-type and hepatocyte specific HIF-1β knockout mice were also subjected to a recently established Gao-binge alcohol model to mimic chronic plus binge conditions, which is quite common in human alcoholics. We found that acute alcohol treatment increased BNIP3 and BNIP3L/NIX expression in primary cultured hepatocytes and in mouse livers, suggesting that HIF may be activated in these models. We further found that hepatocyte-specific HIF-1β knockout mice developed less steatosis and liver injury following the Gao-binge model or acute ethanol treatment compared with their matched wild type mice. Mechanistically, protection against Gao-binge treatment-induced steatosis and liver injury was likely associated with increased FoxO3a activation and subsequent induction of autophagy in hepatocyte-specific HIF-1β knockout mice.

  8. Notch-1 mediates hypoxia-induced angiogenesis in rheumatoid arthritis.

    Science.gov (United States)

    Gao, Wei; Sweeney, Catherine; Connolly, Mary; Kennedy, Aisling; Ng, Chin Teck; McCormick, Jennifer; Veale, Douglas J; Fearon, Ursula

    2012-07-01

    To examine the effect of hypoxia on Notch-1 signaling pathway components and angiogenesis in inflammatory arthritis. The expression and regulation of Notch-1, its ligand delta-like protein 4 (DLL-4) and downstream signaling components (hairy-related transcription factor 1 [HRT-1], HRT-2), and hypoxia-inducible factor 1α (HIF-1α) under normoxic and hypoxic conditions (1-3%) were assessed in synovial tissue specimens from patients with inflammatory arthritis and controls and in human dermal microvascular endothelial cells (HDMECs) by immunohistology, dual immunofluorescence staining (Notch-1/factor VIII), Western blotting, and real-time polymerase chain reaction. In vivo synovial tissue oxygen levels (tissue PO2) were measured under direct visualization at arthroscopy. HDMEC activation under hypoxic conditions in the presence of Notch-1 small interfering RNA (siRNA), the γ-secretase inhibitor DAPT, or dimethyloxalylglycine (DMOG) was assessed by Matrigel tube formation assay, migration assay, invasion assay, and matrix metalloproteinase 2 (MMP-2)/MMP-9 zymography. Expression of Notch-1, its ligand DLL-4, and HRT-1 was demonstrated in synovial tissue, with the strongest expression localized to perivascular/vascular regions. Localization of Notch-1 to synovial endothelium was confirmed by dual immunofluorescence staining. Notch-1 intracellular domain (NICD) expression was significantly higher in synovial tissue from patients with tissue PO2 of PO2 of >20 mm Hg (>3% O2). Exposure of HDMECs to 3% hypoxia induced HIF-1α and NICD protein expression and DLL-4, HRT-1, and HRT-2 messenger RNA expression. DMOG directly induced NICD expression, while Notch-1 siRNA inhibited hypoxia-induced HIF-1α expression, suggesting that Notch-1/HIF-1α signaling is bidirectional. Finally, 3% hypoxia-induced angiogenesis, endothelial cell migration, endothelial cell invasion, and proMMP-2 and proMMP-9 activities were inhibited by Notch-1 siRNA and/or the γ-secretase inhibitor DAPT. Our

  9. Anthrax lethal toxin inhibits translation of hypoxia-inducible factor 1α and causes decreased tolerance to hypoxic stress.

    Science.gov (United States)

    Ouyang, Weiming; Torigoe, Chikako; Fang, Hui; Xie, Tao; Frucht, David M

    2014-02-14

    Hypoxia is considered to be a contributor to the pathology associated with administration of anthrax lethal toxin (LT). However, we report here that serum lactate levels in LT-treated mice are reduced, a finding inconsistent with the anaerobic metabolism expected to occur during hypoxia. Reduced lactate levels are also observed in the culture supernatants of LT-treated cells. LT inhibits the accumulation of hypoxia-inducible factor (HIF)-1α, a subunit of HIF-1, the master regulator directing cellular responses to hypoxia. The toxin has no effect on the transcription or protein turnover of HIF-1α, but instead it acts to inhibit HIF-1α translation. LT treatment diminishes phosphorylation of eIF4B, eIF4E, and rpS6, critical components of the intracellular machinery required for HIF-1α translation. Moreover, blockade of MKK1/2-ERK1/2, but not p38 or JNK signaling, lowers HIF-1α protein levels in both normoxic and hypoxic conditions, consistent with a role for MKK1 and MKK2 as the major targets of LT responsible for the inhibition of HIF-1α translation. The physiological importance of the LT-induced translation blockade is demonstrated by the finding that LT treatment decreases the survival of hepatocyte cell lines grown in hypoxic conditions, an effect that is overcome by preinduction of HIF-1α. Taken together, these data support a role for LT in dysregulating HIF-1α and thereby disrupting homeostatic responses to hypoxia, an environmental characteristic of certain tissues at baseline and/or during disseminated infection with Bacillus anthracis.

  10. CD133 Modulate HIF-1α Expression under Hypoxia in EMT Phenotype Pancreatic Cancer Stem-Like Cells

    Directory of Open Access Journals (Sweden)

    Koki Maeda

    2016-06-01

    Full Text Available Although CD133 is a known representative cancer stem cell marker, its function in tumor aggressiveness under hypoxia is not fully known. The aim of this study is to demonstrate that CD133 regulates hypoxia inducible factor (HIF-1α expression with tumor migration. The CD133+ pancreatic cancer cell line, Capan1M9, was compared with the CD133− cell line, shCD133M9, under hypoxia. HIF-1α expression levels were compared by Western blot, HIF-1α nucleus translocation assay and real-time (RT-PCR. The hypoxia responsive element (HRE was observed by luciferase assay. The migration ability was analyzed by migration and wound healing assays. Epithelial mesenchymal transition (EMT related genes were analyzed by real-time RT-PCR. HIF-1α was highly expressed in Capan1M9 compared to shCD133M9 under hypoxia because of the high activation of HRE. Furthermore, the migration ability of Capan1M9 was higher than that of shCD133M9 under hypoxia, suggesting higher expression of EMT related genes in Capan1M9 compared to shCD133M9. Conclusion: HIF-1α expression under hypoxia in CD133+ pancreatic cancer cells correlated with tumor cell migration through EMT gene expression. Understanding the function of CD133 in cancer aggressiveness provides a novel therapeutic approach to eradicate pancreatic cancer stem cells.

  11. Hypoxic preconditioning protects photoreceptors against light damage independently of hypoxia inducible transcription factors in rods.

    Science.gov (United States)

    Kast, Brigitte; Schori, Christian; Grimm, Christian

    2016-05-01

    Hypoxic preconditioning protects photoreceptors against light-induced degeneration preserving retinal morphology and function. Although hypoxia inducible transcription factors 1 and 2 (HIF1, HIF2) are the main regulators of the hypoxic response, photoreceptor protection does not depend on HIF1 in rods. Here we used rod-specific Hif2a single and Hif1a;Hif2a double knockout mice to investigate the potential involvement of HIF2 in rods for protection after hypoxic preconditioning. To identify potential HIF2 target genes in rods we determined the retinal transcriptome of hypoxic control and rod-specific Hif2a knockouts by RNA sequencing. We show that rods do not need HIF2 for hypoxia-induced increased survival after light exposure. The transcriptomic analysis revealed a number of genes that are potentially regulated by HIF2 in rods; among those were Htra1, Timp3 and Hmox1, candidates that are interesting due to their connection to human degenerative diseases of the retina. We conclude that neither HIF1 nor HIF2 are required in photoreceptors for protection by hypoxic preconditioning. We hypothesize that HIF transcription factors may be needed in other cells to produce protective factors acting in a paracrine fashion on photoreceptor cells. Alternatively, hypoxic preconditioning induces a rod-intrinsic response that is independent of HIF transcription factors. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Effect of hypoxia-inducible factor 1-alpha (HIF-1α) on proliferation ...

    African Journals Online (AJOL)

    Jane

    2011-07-25

    Jul 25, 2011 ... Full Length Research Paper. Effect of hypoxia-inducible factor 1-alpha ... 1Department of Neurosurgery, Ruijin Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200025,. China. 2Department of Neurosurgery, Chaoyang Hospital, Huainan, Anhui, China. 3Department of Neurosurgery ...

  13. mtDNA as a Mediator for Expression of Hypoxia-Inducible Factor 1α and ROS in Hypoxic Neuroblastoma Cells.

    Science.gov (United States)

    Kuo, Chung-Wen; Tsai, Meng-Han; Lin, Tsu-Kung; Tiao, Mao-Meng; Wang, Pei-Wen; Chuang, Jiin-Haur; Chen, Shang-Der; Liou, Chia-Wei

    2017-06-07

    Mitochondria consume O₂ to produce ATP and are critical for adaption of hypoxia, but the role of mitochondria in HIF-1α pathway is as yet unclear. In this study, mitochondrial DNA (mtDNA) enriched (SK-N-AS) and depleted (ρ⁰) cells of neuroblastoma were cultured in a hypoxic chamber to simulate a hypoxic condition and then the major components involved in mitochondrial related pathways, hypoxia-inducible factor 1α (HIF-1α) and reactive oxygen species (ROS) were measured. The results showed that hypoxia-stimulated exposure elevated expression of HIF-1α, which was additionally influenced by level of generated ROS within the cytosol. Moreover, elevation of HIF-1α also resulted in increases of lactate dehydrogenase A (LDH-A) and pyruvate dehydrogenase kinase 1 (PDK1) in both hypoxic cells. The expression of mitochondrial biogenesis related proteins and metabolic components were noted to increase significantly in hypoxic SK-N-AS cells, indicating that mtDNA was involved in mitochondrial retrograde signaling and metabolic pathways. An analysis of dynamic proteins found elevated levels of HIF-1α causing an increased expression of dynamin-related protein 1 (DRP1) during hypoxia; further, the existence of mtDNA also resulted in higher expression of DRP1 during hypoxia. By using siRNA of HIF-1α or DRP1, expression of DRP1 decreased after suppression of HIF-1α; moreover, the expression of HIF-1α was also affected by the suppression of DRP1. In this study, we demonstrated that mtDNA is a mediator of HIF-1α in eliciting metabolic reprogramming, and mitochondrial biogenesis. Identification of a mutual relationship between HIF-1α and DRP1 may be a critical tool in the future development of clinical applications.

  14. Transcription factor HIF1A: downstream targets, associated pathways, polymorphic hypoxia response element (HRE) sites, and initiative for standardization of reporting in scientific literature.

    Science.gov (United States)

    Slemc, Lucija; Kunej, Tanja

    2016-11-01

    Hypoxia-inducible factor-1α (HIF-1α) has crucial role in adapting cells to hypoxia through expression regulation of many genes. Identification of HIF-1α target genes (HIF-1α-TGs) is important for understanding the adapting mechanism. The aim of the present study was to collect known HIF-1α-TGs and identify their associated pathways. Targets and associated genomics data were retrieved using PubMed, WoS ( http://apps.webofknowledge.com/ ), HGNC ( http://www.genenames.org/ ), NCBI ( http://www.ncbi.nlm.nih.gov/ ), Ensemblv.84 ( http://www.ensembl.org/index.html ), DAVID Bioinformatics Resources ( https://david.ncifcrf.gov /), and Disease Ontology database ( http://disease-ontology.org/ ). From 51 papers, we collected 98 HIF-1α TGs found to be associated with 20 pathways, including metabolism of carbohydrates and pathways in cancer. Reanalysis of genomic coordinates of published HREs (hypoxia response elements) revealed six polymorphisms within HRE sites (HRE-SNPs): ABCG2, ACE, CA9, and CP. Due to large heterogeneity of results presentation in scientific literature, we also propose a first step towards reporting standardization of HIF-1α-target interactions consisting of ten relevant data types. Suggested minimal checklist for reporting will enable faster development of a complete catalog of HIF-1α-TGs, data sharing, bioinformatics analyses, and setting novel more targeted hypotheses. The proposed format for data standardization is not yet complete but presents a baseline for further optimization of the protocol with additional details, for example, regarding the experimental validation.

  15. Silver nanoparticles inhibit the function of hypoxia-inducible factor-1 and target genes: insight into the cytotoxicity and antiangiogenesis.

    Science.gov (United States)

    Yang, Tieshan; Yao, Qian; Cao, Fei; Liu, Qianqian; Liu, Binlei; Wang, Xiu-Hong

    Hypoxia-inducible factor-1 (HIF-1) is a transcription factor that is activated upon exposure to hypoxic stress. It modulates a number of cellular responses including proliferation, apoptosis, angiogenesis, and metabolism by activating a panel of target genes in response to hypoxia. The HIF-1 level is often upregulated in the hypoxic microenvironment of solid tumors, which contributes to cancer treatment failure. Here we report that silver nanoparticles (AgNPs), which are widely used as an antimicrobial agent, are an effective inhibitor of HIF-1. AgNPs inhibited the activation of a HIF-dependent reporter construct after the cells were exposed to hypoxic conditions or treated with cobalt chloride, a hypoxia mimetic agent. The AgNPs also interfered with the accumulation of HIF-1α protein and the induction of the endogenous HIF target genes, VEGF-A and GLUT1. Since both HIF-1 and vascular endothelial growth factor-A play an important role in angiogenesis, AgNPs also inhibited angiogenesis in vitro. Our data reveal a new mechanism of how AgNPs act on cellular function, that is, they disrupt HIF signaling pathway. This finding provides a novel insight into how AgNPs can inhibit cancer cell growth and angiogenesis.

  16. Reactive oxygen species (ROS) and the heat stress response of Daphnia pulex: ROS-mediated activation of hypoxia-inducible factor 1 (HIF-1) and heat shock factor 1 (HSF-1) and the clustered expression of stress genes.

    Science.gov (United States)

    Klumpen, Eva; Hoffschröer, Nadine; Zeis, Bettina; Gigengack, Ulrike; Dohmen, Elias; Paul, Rüdiger J

    2017-01-01

    Heat stress in ectotherms involves direct (e.g. protein damage) and/or indirect effects (temperature-induced hypoxia and ROS formation), which cause activation of the transcription factors (TF) heat shock factor 1 (HSF-1) and/or hypoxia-inducible factor 1 (HIF-1). The present study focused on the links between stress (ROS) signals, nuclear (n) and cytoplasmic (c) HSF-1/HIF-1 levels, and stress gene expression on mRNA and protein levels (e.g. heat-shock protein 90, HSP90) upon acute heat and ROS (H 2 O 2 ) stress. Acute heat stress (30°C) evoked fluctuations in ROS level. Different feeding regimens, which affected the glutathione (GSH) level, allowed altering the frequency of ROS fluctuations. Other data showed fluctuation frequency to depend also on ROS production rate. The heat-induced slow or fast ROS fluctuations (at high or low GSH levels) evoked slow or fast fluctuations in the levels of nHIF-1α, nHSF-1 and gene products (mRNAs and protein), albeit after different time delays. Time delays to ROS fluctuations were, for example,shorter for nHIF-1α than for nHSF-1 fluctuations, and nHIF-1α fluctuations preceded and nHSF-1 fluctuations followed fluctuations in HSP90 mRNA level. Cytoplasmic TF levels either changed little (cHIF-1α) or showed a steady increase (cHSF-1). Applying acute H 2 O 2 stress (at 20°C) revealed effects on nHIF-1α and mRNA levels, but no significant effects on nHSF-1 level. Transcriptome data additionally showed coordinated fluctuations of mRNA levels upon acute heat stress, involving mRNAs for HSPs and other stress proteins, with all corresponding genes carrying DNA binding motifs for HIF-1 and HSF-1. This study provided evidence for promoting effects of ROS and HIF-1 on early haemoglobin, HIF-1α and HSP90 mRNA expressions upon heat or ROS stress. The increasing cHSF-1 level likely affected nHSF-1 level and later HSP90 mRNA expression. Heat stress evoked ROS fluctuations, with this stress signal forwarded via nHIF-1 and nHSF-1

  17. The β3-Integrin Binding Protein β3-Endonexin Is a Novel Negative Regulator of Hypoxia-Inducible Factor-1

    Science.gov (United States)

    Kračun, Damir; Rieß, Florian; Kanchev, Ivan; Gawaz, Meinrad

    2014-01-01

    Abstract Aims: Integrins are multifunctional heterodimeric adhesion receptors that mediate the attachment between a cell and the extracellular matrix or other surrounding cells. In endothelial cells, integrins can modulate cell migration and motility. In particular, β3-integrin is expressed in angiogenic vessels. Signal transduction by β3-integrins requires the recruitment of intracellular signaling molecules. β3-endonexin is a highly spliced molecule that has been identified as a β3-integrin binding protein. β3-endonexin isoforms are expressed in endothelial cells and have been suggested to act as shuttle proteins between the membrane and the nucleus. However, their functional role in angiogenesis is unclear. In this study, we investigated whether β3-endonexin isoforms are involved in endothelial angiogenic processes under hypoxia. Results: The overexpression of β3-endonexin isoforms decreased endothelial proliferation and tube formation under hypoxia, while the depletion of β3-endonexin by RNAi promoted angiogenic responses in vitro and in vivo. In hypoxia, β3-endonexin accumulated in the nucleus, and prevention of this response by depletion of β3-endonexin increased hypoxic activation and induction of the hypoxia-inducible factor (HIF)-1 and its target genes VEGF and PAI-1. β3-endonexin diminished nuclear factor kappa B (NFκB) activation and decreased NFκB binding to the HIF-1α promoter under hypoxia, subsequently diminishing NFκB-dependent transcription of HIF-1α under hypoxia. Innovation: Our results indicate for the first time that the overexpression of β3-endonexin can decrease hypoxic induction and activation of HIF-1α and can prevent hypoxic endothelial proliferation and angiogenic responses. Conclusion: β3-endonexin can act as a novel anti-angiogenic factor specifically in the response to hypoxia due to its negative impact on the activation of HIF-1. Antioxid. Redox Signal. 20, 1964–1976. PMID:24386901

  18. Inhibition of HIF-1{alpha} activity by BP-1 ameliorates adjuvant induced arthritis in rats

    Energy Technology Data Exchange (ETDEWEB)

    Shankar, J. [Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago (United States); Thippegowda, P.B., E-mail: btprabha@uic.edu [Department of Pharmacology, (M/C 868), College of Medicine, University of Illinois at Chicago, 835 S. Wolcott Ave., Chicago, IL 60612 (United States); Kanum, S.A. [Department of Chemistry, Yuvaraj' s College, University of Mysore, Mysore (India)

    2009-09-18

    Rheumatoid arthritis (RA) is a chronic inflammatory, angiogenic disease. Inflamed synovitis is a hallmark of RA which is hypoxic in nature. Vascular endothelial growth factor (VEGF), one of the key regulators of angiogenesis, is overexpressed in the pathogenesis of RA. VEGF expression is regulated by hypoxia-inducible factor-1{alpha} (HIF-1{alpha}), a master regulator of homeostasis which plays a pivotal role in hypoxia-induced angiogenesis. In this study we show that synthetic benzophenone analogue, 2-benzoyl-phenoxy acetamide (BP-1) can act as a novel anti-arthritic agent in an experimental adjuvant induced arthritis (AIA) rat model by targeting VEGF and HIF-1{alpha}. BP-1 administered hypoxic endothelial cells and arthritic animals clearly showed down regulation of VEGF expression. Further, BP-1 inhibits nuclear translocation of HIF-1{alpha}, which in turn suppresses transcription of the VEGF gene. These results suggest a further possible clinical application of the BP-1 derivative as an anti-arthritic agent in association with conventional chemotherapeutic agents.

  19. MDM2 regulates hypoxic hypoxia-inducible factor 1α stability in an E3 ligase, proteasome, and PTEN-phosphatidylinositol 3-kinase-AKT-dependent manner.

    Science.gov (United States)

    Joshi, Shweta; Singh, Alok R; Durden, Donald L

    2014-08-15

    Hypoxia-inducible factor 1 (HIF1) is a heterodimeric transcription factor containing an inducibly expressed HIF1α subunit and a constitutively expressed HIF1β subunit. Under hypoxic conditions, the HIF1α subunit accumulates because of a decrease in the rate of proteolytic degradation, and the resulting HIF1α-HIF1β heterodimers undergo post-translational modifications that promote transactivation. Previous reports suggest that amplified signaling through PI3K enhances HIF1-dependent gene expression; however, its role is controversial, and the mechanism is unclear. Using genetically engineered PTEN-deficient cell lines, we demonstrate that PTEN specifically inhibited the accumulation of HIF1α in response to hypoxia. Furthermore, we report that in glioblastoma cell lines, inhibition of PI3K pathway, using pan as well as isoform-specific PI3K inhibitors SF1126, PF4691502, BEZ-235, GDC0941, and TGX221 blocked the induction of HIF1α protein and its targets vascular endothelial growth factor, HK1, and GLUT1 mRNA in response to hypoxia. Herein, we describe the first evidence that HIF1α can be degraded under hypoxic conditions via the 26 S proteasome and that MDM2 is the E3 ligase that induces the hypoxic degradation of HIF1α. Moreover, the action of MDM2 on HIF1α under hypoxia occurs in the cytoplasm and is controlled by the PTEN-PI3K-AKT signaling axis. These data strongly suggest a new role for PTEN in the regulation of HIF1α and importantly that PI3K-AKT activation is required for the hypoxic stabilization of HIF1α and that hypoxia alone is not sufficient to render HIF1α resistant to proteasomal cleavage and degradation. Moreover, these findings suggest new therapeutic considerations for PI3K and/or AKT inhibitors for cancer therapeutics. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. MDM2 Regulates Hypoxic Hypoxia-inducible Factor 1α Stability in an E3 Ligase, Proteasome, and PTEN-Phosphatidylinositol 3-Kinase-AKT-dependent Manner*

    Science.gov (United States)

    Joshi, Shweta; Singh, Alok R.; Durden, Donald L.

    2014-01-01

    Hypoxia-inducible factor 1 (HIF1) is a heterodimeric transcription factor containing an inducibly expressed HIF1α subunit and a constitutively expressed HIF1β subunit. Under hypoxic conditions, the HIF1α subunit accumulates because of a decrease in the rate of proteolytic degradation, and the resulting HIF1α–HIF1β heterodimers undergo post-translational modifications that promote transactivation. Previous reports suggest that amplified signaling through PI3K enhances HIF1-dependent gene expression; however, its role is controversial, and the mechanism is unclear. Using genetically engineered PTEN-deficient cell lines, we demonstrate that PTEN specifically inhibited the accumulation of HIF1α in response to hypoxia. Furthermore, we report that in glioblastoma cell lines, inhibition of PI3K pathway, using pan as well as isoform-specific PI3K inhibitors SF1126, PF4691502, BEZ-235, GDC0941, and TGX221 blocked the induction of HIF1α protein and its targets vascular endothelial growth factor, HK1, and GLUT1 mRNA in response to hypoxia. Herein, we describe the first evidence that HIF1α can be degraded under hypoxic conditions via the 26 S proteasome and that MDM2 is the E3 ligase that induces the hypoxic degradation of HIF1α. Moreover, the action of MDM2 on HIF1α under hypoxia occurs in the cytoplasm and is controlled by the PTEN-PI3K-AKT signaling axis. These data strongly suggest a new role for PTEN in the regulation of HIF1α and importantly that PI3K-AKT activation is required for the hypoxic stabilization of HIF1α and that hypoxia alone is not sufficient to render HIF1α resistant to proteasomal cleavage and degradation. Moreover, these findings suggest new therapeutic considerations for PI3K and/or AKT inhibitors for cancer therapeutics. PMID:24982421

  1. Hypoxia-Inducible Factor 1 Is an Inductor of Transcription Factor Activating Protein 2 Epsilon Expression during Chondrogenic Differentiation

    Directory of Open Access Journals (Sweden)

    Stephan Niebler

    2015-01-01

    Full Text Available The transcription factor AP-2ε (activating enhancer-binding protein epsilon is expressed in cartilage of humans and mice. However, knowledge about regulatory mechanisms influencing AP-2ε expression is limited. Using quantitative real time PCR, we detected a significant increase in AP-2ε mRNA expression comparing initial and late stages of chondrogenic differentiation processes in vitro and in vivo. Interestingly, in these samples the expression pattern of the prominent hypoxia marker gene angiopoietin-like 4 (Angptl4 strongly correlated with that of AP-2ε suggesting that hypoxia might represent an external regulator of AP-2ε expression in mammals. In order to show this, experiments directly targeting the activity of hypoxia-inducible factor-1 (HIF1, the complex mediating responses to oxygen deprivation, were performed. While the HIF1-activating compounds 2,2′-dipyridyl and desferrioxamine resulted in significantly enhanced mRNA concentration of AP-2ε, siRNA against HIF1α led to a significantly reduced expression rate of AP-2ε. Additionally, we detected a significant upregulation of the AP-2ε mRNA level after oxygen deprivation. In sum, these different experimental approaches revealed a novel role for the HIF1 complex in the regulation of the AP-2ε gene in cartilaginous cells and underlined the important role of hypoxia as an important external regulatory stimulus during chondrogenic differentiation modulating the expression of downstream transcription factors.

  2. Andrographolide inhibits hypoxia-inducible factor-1 through phosphatidylinositol 3-kinase/AKT pathway and suppresses breast cancer growth

    Directory of Open Access Journals (Sweden)

    Li J

    2015-02-01

    Full Text Available Jie Li,1 Chao Zhang,1 Hongchuan Jiang,1 Jiao Cheng21Department of General Surgery, 2Department of Gynaecology and Obstetrics, Beijing Chao-Yang Hospital, Beijing, People’s Republic of ChinaAbstract: Hypoxia-inducible factor-1 (HIF-1 is a master regulator of the transcriptional response to hypoxia. HIF-1α is one of the most compelling anticancer targets. Andrographolide (Andro was newly identified to inhibit HIF-1 in T47D cells (a half maximal effective concentration [EC50] of 1.03×10-7 mol/L, by a dual-luciferase reporter assay. It suppressed HIF-1α protein and gene accumulation, which was dependent on the inhibition of upstream phosphatidylinositol 3-kinase (PI3K/AKT pathway. It also abrogated the expression of HIF-1 target vascular endothelial growth factor (VEGF gene and protein. Further, Andro inhibited T47D and MDA-MB-231 cell proliferation and colony formation. In addition, it exhibited significant in vivo efficacy and antitumor potential against the MDA-MB-231 xenograft in nude mice. In conclusion, these results highlighted the potential effects of Andro, which inhibits HIF-1, and hence may be developed as an antitumor agent for breast cancer therapy in future.Keywords: Andrographolide (Andro, HIF-1α, inhibit, breast cancer, hypoxia, PI3k/AKT/mTOR pathway

  3. Hypoxia-inducible factor-1α, vascular endothelial growth factor, inducible nitric oxide synthase, and endothelin-1 expression correlates with angiogenesis in congenital heart disease

    Directory of Open Access Journals (Sweden)

    Hsin-Ling Yin

    2016-07-01

    Full Text Available In Taiwan, the average prevalence of congenital heart disease (CHD is 13.08/1000 live births. Most children with CHD die before the age of 5 years; therefore, identifying treatment methods to extend the life of CHD patients is an important issue in clinical practice. The objective of this study is to evaluate the roles of hypoxia-inducible factor-1α (HIF-1α, vascular endothelial growth factor (VEGF, inducible nitric oxide synthase (iNOS, endothelin-1 (ET-1, and CD34 in CHD autopsy cases in comparison with autopsy cases without CHD. The study included 19 autopsy cases, which were divided into the following four groups: acyanotic CHD (n = 11, cyanotic CHD (n = 3, CHD associated with chromosomal abnormalities (n = 3, and complex CHD (n = 2. Heart specimens obtained from 10 autopsy cases without CHD were included as controls. Our results indicated that high percentages of HIF-1α (100%, VEGF (89.5%, iNOS (78.9%, and ET-1 (84.2% expressions were observed in CHD autopsy cases and this was found to be significant. HIF-1α induced by hypoxia could play a potential role in relating downstream gene expressions in CHD patients. Upregulation of VEGF by HIF-1α could play an important role in triggering angiogenesis to protect myocardial cell survival in a hypoxic microenvironment. Therefore, HIF-1α could be a significant prognosis marker in CHD and be a prospective candidate in the development of target therapy in cardiovascular diseases.

  4. Correlation between expressions of hypoxia -inducible factor (HIF-1α, blood vessels density, cell proliferation, and apoptosis intensity in canine fibromas and fibrosarcomas

    Directory of Open Access Journals (Sweden)

    Madej Janusz A.

    2014-03-01

    Full Text Available The study aimed to demonstrate the expression of hypoxia-inducible factor (HIF-1α in soft tissue mesenchymal tumours (fibroma and fibrosarcoma in dogs. An attempt was made to correlate the obtained results with density of blood vessels (expression of von Willebrand Factor, vWF, expression of Ki-67 proliferation antigen, and with intensity of apoptosis in studied tumours. The study was performed on paraffin sections of 15 fibromas and 40 fibrosarcomas sampled from 55 female dogs aged 6 to 16 years. Immunohistochemical staining against HIF-1α, vWF, and Ki-67 was performed. Apoptosis was detected with the use of TUNEL reaction. A significantly higher HIF-1α expression was noted in fibrosarcomas in comparison to fibromas (P < 0.0001. HIF-1α expression in fibromas manifested strong positive correlation with tumour vascularity (r = 0.67, P = 0.007. Moreover, HIF-1α expression in fibrosarcomas manifested a moderate positive correlation with tumour malignancy grade (r = 0.44, P = 0.004, tumour vascularity (r = 0.52, P < 0.001, Ki-67 antigen expression (r = 0.42; P = 0.007, and TUNELpositive cells (r = 0.37, P = 0.017. Expression of HIF-1α was detected in 86.7% of fibroma type tumours and in 100% of fibrosarcomas. In all studied tumours expression of HIF-1α manifested positive correlation with the density of blood vessels, and in fibrosarcomas it correlated also with malignancy grade, intensity of Ki-67 expression, and with intensity of apoptosis in tumour cells.

  5. Rapid detection of hypoxia-inducible factor-1-active tumours: pretargeted imaging with a protein degrading in a mechanism similar to hypoxia-inducible factor-1{alpha}

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, Masashi [Kyoto University, Radioisotopes Research Laboratory, Kyoto University Hospital, Faculty of Medicine, Kyoto (Japan); Kyoto University, Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto (Japan); Kudo, Takashi; Konishi, Hiroaki; Miyano, Azusa; Ono, Masahiro; Saji, Hideo [Kyoto University, Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto (Japan); Kuge, Yuji [Kyoto University, Department of Patho-Functional Bioanalysis, Graduate School of Pharmaceutical Sciences, Kyoto (Japan); Hokkaido University, Central Institute of Isotope Science, Sapporo (Japan); Mukai, Takahiro [Kyushu University, Department of Biomolecular Recognition Chemistry, Graduate School of Pharmaceutical Sciences, Fukuoka (Japan); Tanaka, Shotaro; Kizaka-Kondoh, Shinae; Hiraoka, Masahiro [Kyoto University, Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto (Japan)

    2010-08-15

    Hypoxia-inducible factor-1 (HIF-1) plays an important role in malignant tumour progression. For the imaging of HIF-1-active tumours, we previously developed a protein, POS, which is effectively delivered to and selectively stabilized in HIF-1-active cells, and a radioiodinated biotin derivative, (3-{sup 123}I-iodobenzoyl)norbiotinamide ({sup 123}I-IBB), which can bind to the streptavidin moiety of POS. In this study, we aimed to investigate the feasibility of the pretargeting method using POS and {sup 123}I-IBB for rapid imaging of HIF-1-active tumours. Tumour-implanted mice were pretargeted with POS. After 24 h, {sup 125}I-IBB was administered and subsequently, the biodistribution of radioactivity was investigated at several time points. In vivo planar imaging, comparison between {sup 125}I-IBB accumulation and HIF-1 transcriptional activity, and autoradiography were performed at 6 h after the administration of {sup 125}I-IBB. The same sections that were used in autoradiographic analysis were subjected to HIF-1{alpha} immunohistochemistry. {sup 125}I-IBB accumulation was observed in tumours of mice pretargeted with POS (1.6%ID/g at 6 h). This result is comparable to the data derived from {sup 125}I-IBB-conjugated POS-treated mice (1.4%ID/g at 24 h). In vivo planar imaging provided clear tumour images. The tumoral accumulation of {sup 125}I-IBB significantly correlated with HIF-1-dependent luciferase bioluminescence (R=0.84, p<0.01). The intratumoral distribution of {sup 125}I-IBB was heterogeneous and was significantly correlated with HIF-1{alpha}-positive regions (R=0.58, p<0.0001). POS pretargeting with {sup 123}I-IBB is a useful technique in the rapid imaging and detection of HIF-1-active regions in tumours. (orig.)

  6. Hypoxia-inducible factor-1α/interleukin-1β signaling enhances hepatoma epithelial-mesenchymal transition through macrophages in a hypoxic-inflammatory microenvironment.

    Science.gov (United States)

    Zhang, Jingying; Zhang, Qi; Lou, Yu; Fu, Qihan; Chen, Qi; Wei, Tao; Yang, Jiaqi; Tang, Jinlong; Wang, Jianxin; Chen, Yiwen; Zhang, Xiaoyu; Zhang, Jian; Bai, Xueli; Liang, Tingbo

    2018-05-01

    The development and progression of hepatocellular carcinoma (HCC) are dependent on its local microenvironment. Hypoxia and inflammation are two critical factors that shape the HCC microenvironment; however, the interplay between the two factors and the involvement of cancer cells under such conditions remain poorly understood. We found that tumor-associated macrophages, the primary proinflammatory cells within tumors, secreted more interleukin 1β (IL-1β) under moderate hypoxic conditions due to increased stability of hypoxia inducible factor 1α (HIF-1α). Under persistent and severe hypoxia, we found that the necrotic debris of HCC cells induced potent IL-1β release by tumor-associated macrophages with an M2 phenotype. We further confirmed that the necrotic debris-induced IL-1β secretion was mediated through Toll-like receptor 4/TIR domain-containing adapter-inducing interferon-β/nuclear factor kappa-light-chain-enhancer of activated B cells signaling in a similar, but not identical, fashion to lipopolysaccharide-induced inflammation. Using mass spectrometry, we identified a group of proteins with O-linked glycosylation to be responsible for the necrotic debris-induced IL-1β secretion. Following the increase of IL-1β in the local microenvironment, the synthesis of HIF-1α was up-regulated by IL-1β in HCC cells through cyclooxygenase-2. The epithelial-mesenchymal transition of HCC cells was enhanced by overexpression of HIF-1α. We further showed that IL-1β promoted HCC metastasis in mouse models and was predictive of poor prognosis in HCC patients. Our findings revealed an HIF-1α/IL-1β signaling loop between cancer cells and tumor-associated macrophages in a hypoxic microenvironment, resulting in cancer cell epithelial-mesenchymal transition and metastasis; more importantly, our results suggest a potential role of an anti-inflammatory strategy in HCC treatment. (Hepatology 2018;67:1872-1889). © 2017 by the American Association for the Study of Liver

  7. Genome-wide identification of hypoxia-inducible factor-1 and -2 binding sites in hypoxic human macrophages alternatively activated by IL-10.

    Science.gov (United States)

    Tausendschön, Michaela; Rehli, Michael; Dehne, Nathalie; Schmidl, Christian; Döring, Claudia; Hansmann, Martin-Leo; Brüne, Bernhard

    2015-01-01

    Macrophages (MΦ) often accumulate in hypoxic areas, where they significantly influence disease progression. Anti-inflammatory cytokines, such as IL-10, generate alternatively activated macrophages that support tumor growth. To understand how alternative activation affects the transcriptional profile of hypoxic macrophages, we globally mapped binding sites of hypoxia-inducible factor (HIF)-1α and HIF-2α in primary human monocyte-derived macrophages prestimulated with IL-10. 713 HIF-1 and 795 HIF-2 binding sites were identified under hypoxia. Pretreatment with IL-10 altered the binding pattern, with 120 new HIF-1 and 188 new HIF-2 binding sites emerging. HIF-1 binding was most prominent in promoters, while HIF-2 binding was more abundant in enhancer regions. Comparison of ChIP-seq data obtained in other cells revealed a highly cell type specific binding of HIF. In MΦ HIF binding occurred preferentially in already active enhancers or promoters. To assess the roles of HIF on gene expression, primary human macrophages were treated with siRNA against HIF-1α or HIF-2α, followed by genome-wide gene expression analysis. Comparing mRNA expression to the HIF binding profile revealed a significant enrichment of hypoxia-inducible genes previously identified by ChIP-seq. Analysis of gene expression under hypoxia alone and hypoxia/IL-10 showed the enhanced induction of a set of genes including PLOD2 and SLC2A3, while another group including KDM3A and ADM remained unaffected or was reduced by IL-10. Taken together IL-10 influences the DNA binding pattern of HIF and the level of gene induction. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Hypoxia-inducible factor-1α regulates chemotactic migration of pancreatic ductal adenocarcinoma cells through directly transactivating the CX3CR1 gene.

    Directory of Open Access Journals (Sweden)

    Tiansuo Zhao

    Full Text Available CX3CR1 is an important chemokine receptor and regulates the chemotactic migration of pancreatic ductal adenocarcinoma (PDAC cells. Up to now, its regulatory mechanism remains largely undefined. Here, we report that hypoxia upregulates the expression of CX3CR1 in pancreatic cancer cells. When hypoxia-inducible factor (HIF-1α expression was knocked down in vitro and in vivo, the expression of CX3CR1 was significantly decreased. Chromatin immunoprecipitation assay demonstrated that HIF-1α bound to the hypoxia-response element (HRE; 5'-A/GCGTG-3' of CX3CR1 promoter under normoxia, and this binding was significantly enhanced under hypoxia. Overexpression of HIF-1α significantly upregulated the expression of luciferase reporter gene under the control of the CX3CR1 promoter in pancreatic cancer cells. Importantly, we demonstrated that HIF-1α may regulate cancer cell migration through CX3CR1. The HIF-1α/CX3CR1 pathway might represent a valuable therapeutic target to prevent invasion and distant metastasis in PDAC.

  9. Low hypoxia inducible factor-1α (HIF-1α) expression in testicular germ cell tumors - a major reason for enhanced chemosensitivity?

    Science.gov (United States)

    Shenoy, Niraj; Dronca, Roxana; Quevedo, Fernando; Boorjian, Stephen A; Cheville, John; Costello, Brian; Kohli, Manish; Witzig, Thomas; Pagliaro, Lance

    2017-08-01

    The molecular basis for enhanced chemosensitivity of testicular germ cell tumors (GCT) has been an area of great interest, as it could potentially give us therapeutic leads in other resistant malignancies. Thus far, however, the increased sensitivity of GCT has been variously attributed to multiple factors - an inability to detoxify cisplatin, a lack of export pumps, an inability to repair the DNA damage, an intact apoptotic cascade and lack of p53 mutation; but a unifying underlying etiology leading to the aforementioned processes and having a translational implication has so far been elusive. Herein, we offer evidence to support a potential significant role for the previously demonstrated low hypoxia inducible factor-1α (HIF-1α) expression in mediating the general exquisite chemosensitivity of testicular GCT, through the aforementioned processes. This molecular mechanism based hypothesis could have a significant translational implication in platinum refractory GCT as well as other platinum resistant malignancies.

  10. Thiamine deficiency activates hypoxia inducible factor-1α to facilitate pro-apoptotic responses in mouse primary astrocytes.

    Directory of Open Access Journals (Sweden)

    Kristy Zera

    Full Text Available Thiamine is an essential enzyme cofactor required for proper metabolic function and maintenance of metabolism and energy production in the brain. In developed countries, thiamine deficiency (TD is most often manifested following chronic alcohol consumption leading to impaired mitochondrial function, oxidative stress, inflammation and excitotoxicity. These biochemical lesions result in apoptotic cell death in both neurons and astrocytes. Comparable histological injuries in patients with hypoxia/ischemia and TD have been described in the thalamus and mammillary bodies, suggesting a congruency between the cellular responses to these stresses. Consistent with hypoxia/ischemia, TD stabilizes and activates Hypoxia Inducible Factor-1α (HIF-1α under physiological oxygen levels. However, the role of TD-induced HIF-1α in neurological injury is currently unknown. Using Western blot analysis and RT-PCR, we have demonstrated that TD induces HIF-1α expression and activity in primary mouse astrocytes. We observed a time-dependent increase in mRNA and protein expression of the pro-apoptotic and pro-inflammatory HIF-1α target genes MCP1, BNIP3, Nix and Noxa during TD. We also observed apoptotic cell death in TD as demonstrated by PI/Annexin V staining, TUNEL assay, and Cell Death ELISA. Pharmacological inhibition of HIF-1α activity using YC1 and thiamine repletion both reduced expression of pro-apoptotic HIF-1α target genes and apoptotic cell death in TD. These results demonstrate that induction of HIF-1α mediated transcriptional up-regulation of pro-apoptotic/inflammatory signaling contributes to astrocyte cell death during thiamine deficiency.

  11. Hypoxia Inducible Factor Signaling and Experimental Persistent Pulmonary Hypertension of the Newborn: A Therapeutic Opportunity

    Directory of Open Access Journals (Sweden)

    Stephen eWedgwood

    2015-03-01

    Full Text Available BACKGROUND: Mitochondrial reactive oxygen species levels and nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB activity are increased in a lamb model of persistent pulmonary hypertension of the newborn (PPHN. These events can trigger hypoxia inducible factor (HIF signaling in response to hypoxia, which has been shown to contribute to pulmonary vascular remodeling in rodent models of pulmonary hypertension. However the role of HIF signaling in chronic intrauterine pulmonary hypertension is not well understood.AIM: To determine if HIF signaling is increased in the lamb model of PPHN, and to identify the underlying mechanisms. RESULTS: PPHN was induced in lambs by antenatal ligation of the ductus arteriosus at 128 days gestation. After 9 days, lungs and pulmonary artery smooth muscle cells (PASMC were isolated from control and PPHN lambs. HIF-1α expression was increased in PPHN lungs and HIF activity was increased in PPHN PASMC relative to controls. Hypoxia increased HIF activity to a greater degree in PPHN vs. control PASMC. Control PASMC were exposed to cyclic stretch at 1Hz and 15% elongation for 24h, as an in vitro model of vascular stress. Stretch increased HIF activity, which was attenuated by inhibition of mitochondrial complex III and NFκB.CONCLUSION: Increased HIF signaling in PPHN is triggered by stretch, via mechanisms involving mitochondrial ROS and NFκB. Hypoxia substantially amplifies HIF activity in PPHN vascular cells. Targeting these signaling molecules may attenuate and reverse pulmonary vascular remodeling associated with PPHN.

  12. Protein arginine methyltransferase 5 is an essential component of the hypoxia-inducible factor 1 signaling pathway

    International Nuclear Information System (INIS)

    Lim, Ji-Hong; Choi, Yong-Joon; Cho, Chung-Hyun; Park, Jong-Wan

    2012-01-01

    Highlights: ► HIF-1α is expressed PRMT5-dependently in hypoxic cancer cells. ► The HIF-1 regulation of hypoxia-induced genes is attenuated in PRMT5-knocked-down cells. ► The de novo synthesis of HIF-1α depends on PRMT5. ► PRMT5 is involved in the HIF-1α translation initiated by 5′ UTR of HIF-1α mRNA. -- Abstract: Protein arginine methyltransferase 5 (PRMT5) is an enzyme that transfers one or two methyl groups to the arginine residues of histones or non-histone proteins, and that plays critical roles in cellular processes as diverse as receptor signaling and gene expression. Furthermore, PRMT5 is highly expressed in tumors, where it may be associated with tumor growth. Although much research has been conducted on PRMT5, little is known regarding its role in adaption to hypoxia. As hypoxia-inducible factor 1 (HIF-1) is a key player in hypoxic response, we examined the possible involvement of PRMT5 in the HIF-1 signaling pathway. Of the siRNAs targeting PRMT1–8, only PRMT5 siRNA attenuated the hypoxic induction of HIF-1α in A549 cells, and this result was reproducible in all three cancer cell lines examined. PRMT5 knock-down also repressed the promoter activities and the transcript levels of HIF-1-governed genes. Mechanistically, de novo synthesis of HIF-1α protein was reduced in PRMT5-knocked-down A549 cells, and this was rescued by PRMT5 restoration. In contrast, HIF-1α transcription, RNA processing, and protein stability were unaffected by PRMT5 knock-down. Furthermore, PRMT5 was found to be essential for the HIF-1α translation initiated by the 5′ UTR of HIF-1α mRNA. Given our results and previous reports, we believe that PRMT5 probably promotes tumor growth by stimulating cell proliferation and by participating in the construction of a tumor-favorable microenvironment via HIF-1 activation.

  13. The role of metformin and resveratrol in the prevention of hypoxia-inducible factor 1α accumulation and fibrosis in hypoxic adipose tissue.

    Science.gov (United States)

    Li, Xiaole; Li, Jia; Wang, Lulu; Li, Aiyun; Qiu, Zhixia; Qi, Lian-Wen; Kou, Junping; Liu, Kang; Liu, Baolin; Huang, Fang

    2016-06-01

    Hypoxic activation of hypoxia-inducible factor 1α (HIF-1α) and fibrosis in adipose tissue contribute to adipose dysfunction. This study was designed to investigate the effects of metformin and resveratrol on the regulation of HIF-1α and fibrosis in hypoxic adipose tissue. Mice were fed a high-fat diet to induce hypoxia and fibrosis in adipose tissue; adipose tissue incubated in vitro in 1% O2 showed a similar change. The effects of metformin and resveratrol on hypoxia, HIF-1α accumulation, endoplasmic reticulum stress and gene expressions of extracellular matrix components and pro-inflammatory cytokines were examined. Oral administration of metformin or resveratrol prevented hypoxia and reduced HIF-1α accumulation with dephosphorylation of inositol-requiring enzyme 1α and eukaryotic initiation factor 2α, indicative of suppression of hypoxic HIF-1α activation and endoplasmic reticulum stress. Metformin and resveratrol down-regulated gene expressions of Col3α, Col6α, elastin and lysyl oxidase and thereby reduced collagen deposition in adipose tissue. The increased gene expressions of TNF-α, IL-6, monocyte chemoattractant protein 1 and F4/80 were also down-regulated by metformin and resveratrol. Metformin and resveratrol had similar effects in adipose tissue exposed to 1% O2 . Metformin reduced ATP production and prevented the reduction in oxygen tension in 3T3-L1 cells, suggesting that it prevented hypoxia by limiting oxygen consumption, whereas resveratrol reduced HIF-1α accumulation by promoting its proteasomal degradation via the regulation of AMPK/SIRT1. Hypoxia and fibrosis are early causes of adipose dysfunction in obesity. Both metformin and resveratrol effectively inhibited HIF-1α activation-induced fibrosis and inflammation in adipose tissue, although by different mechanisms. © 2016 The British Pharmacological Society.

  14. In vitro ischemia suppresses hypoxic induction of hypoxia-inducible factor-1α by inhibition of synthesis and not enhanced degradation.

    Science.gov (United States)

    Karuppagounder, Saravanan S; Basso, Manuela; Sleiman, Sama F; Ma, Thong C; Speer, Rachel E; Smirnova, Natalya A; Gazaryan, Irina G; Ratan, Rajiv R

    2013-08-01

    Hypoxia-inducible factor (HIF) mediates a broad, conserved adaptive response to hypoxia, and the HIF pathway is a potential therapeutic target in cerebral ischemia. This study investigated the mechanism by which in vitro ischemia (oxygen-glucose deprivation; OGD) affects canonical hypoxic HIF-1α stabilization. We validated the use of a reporter containing the oxygen-dependent degradation domain of HIF-1α fused to firefly luciferase (ODD-luc) to monitor quantitatively distinct biochemical events leading to hypoxic HIF-1α expression or stabilization in a human neuroblastoma cell line (SH-SY5Y). When OGD was imposed following a 2-hr hypoxic stabilization of ODD-luc, the levels of the reporter were reduced, consistent with prior models proposing that OGD enhances HIF prolylhydroxylase (PHD) activity. Surprisingly, PHD inhibitors and proteasome inhibitors do not stabilize ODD-luc in OGD. Furthermore, OGD does not affect the half-life of ODD-luc protein following hypoxia, suggesting that OGD abrogates hypoxic HIF-1α induction by reducing HIF-1α synthesis rather than by enhancing its degradation. We observed ATP depletion under OGD vs. hypoxia and propose that ATP depletion enhances translational suppression, overcoming the selective synthesis of HIF concurrent with global decreases in protein synthesis in hypoxia. Taken together, these findings biochemically characterize a practical reporter for monitoring HIF-1α levels and support a novel model for HIF regulation in an in vitro model of human ischemia. Copyright © 2013 Wiley Periodicals, Inc.

  15. Expression of angiopoietin-1 in hypoxic pericytes: Regulation by hypoxia-inducible factor-2α and participation in endothelial cell migration and tube formation.

    Science.gov (United States)

    Park, Yoon Shin; Kim, Gyungah; Jin, Yoon Mi; Lee, Jee Young; Shin, Jong Wook; Jo, Inho

    2016-01-08

    We previously reported that hypoxia increases angiopoietin-1 (Ang1), but not Ang2, mRNA expression in bovine retinal pericytes (BRP). However, the mechanism underlying Ang1 expression is unknown. Here, we report that Ang1 protein expression increased in hypoxic BRP in a dose- and time-dependent manner. This increase was accompanied by an increase in hypoxia-inducible factor-2α (HIF2α) expression. Transfection with an antisense oligonucleotide for HIF2α partially inhibited the hypoxia-induced increase in Ang1 expression. HIF2α overexpression further potentiated hypoxia-stimulated Ang1 expression, suggesting that HIF2α plays an important role in Ang1 regulation in BRP. When fused the Ang1 promoter (-3040 to +199) with the luciferase reporter gene, we found that hypoxia significantly increased promoter activity by 4.02 ± 1.68 fold. However, progressive 5'-deletions from -3040 to -1799, which deleted two putative hypoxia response elements (HRE), abolished the hypoxia-induced increase in promoter activity. An electrophoretic mobility shift assay revealed that HIF2α was predominantly bound to a HRE site, located specifically at nucleotides -2715 to -2712. Finally, treatment with conditioned medium obtained from hypoxic pericytes stimulated endothelial cell migration and tube formation, which was completely blocked by co-treatment with anti-Ang1 antibody. This study is the first to demonstrate that hypoxia upregulates Ang1 expression via HIF2α-mediated transcriptional activation in pericytes, which plays a key role in angiogenesis. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Regular endurance training reduces the exercise induced HIF-1alpha and HIF-2alpha mRNA expression in human skeletal muscle in normoxic conditions

    DEFF Research Database (Denmark)

    Lundby, Carsten; Gassmann, Max; Pilegaard, Henriette

    2005-01-01

    and 2 (HIFs) are clearly related heterodimeric transcription factors that consist of an oxygen-depended alpha-subunit and a constitutive beta-subunit. With hypoxic exposure, HIF-1alpha and HIF-2alpha protein are stabilized. Upon heterodimerization, HIFs induce the transcription of a variety of genes......Regular exercise induces a variety of adaptive responses that enhance the oxidative and metabolic capacity of human skeletal muscle. Although the physiological adjustments of regular exercise have been known for decades, the underlying mechanisms are still unclear. The hypoxia inducible factors 1...... including erythropoietin (EPO), transferrin and its receptor, as well as vascular endothelial growth factor (VEGF) and its receptor. Considering that several of these genes are also induced with exercise, we tested the hypothesis that the mRNA level of HIF-1alpha and HIF-2alpha subunits increases...

  17. [Effects of interleukin-18 and hypoxia-inducible factor-1α in serum and gingival tissues of rat model with periodontitis exposed to chronic intermittent hypoxia].

    Science.gov (United States)

    Wang, Bin; Wang, Xiaoqin

    2015-08-01

    This study evaluates the expression of interleukin-18 (IL-18) and hypoxia-inducible factor (HIF)-lα in rat periodontitis model exposed to normoxia and chronic intermittent hypoxia (CIH) environments. The possible correlation between periodontitis and obstructive sleep apnea-hypopnea syndrome (OSAHS) was also investigated. Methods: Thirty-two Sprague-Dawley (SD) rats were randomly assigned into four groups: normoxia control, normoxia periodontitis, hypoxia control, and hypoxia periodontitis groups. The periodontitis models were established by ligating the bilateral maxillary second molars and employing high-carbohydrate diets. Rats in hypoxia control and hypoxia periodontitis groups were exposed to CIH treatment mimicking a moderately severe OSAHS condition. All animals were sacrificed after eight weeks, and the clinical periodontal indexes were detected. The levels of IL-18 and HIF-1α in serum and gingival tissues were determined using enzyme-linked immunosorbent assay (ELISA). The correlation between attachment loss (AL) and the levels of IL-18 and HIF-lα in hypoxia periodontitis group was evaluated. The levels of IL-18 and HIF-lα in hypoxia periodontitis group were significantly higher than that in normoxia periodontitis and hypoxia control groups (Pperiodontal tissues, which is correlated with IL-18 and HIF-lα levels.

  18. Hypoxia Downregulates MAPK/ERK but Not STAT3 Signaling in ROS-Dependent and HIF-1-Independent Manners in Mouse Embryonic Stem Cells

    Directory of Open Access Journals (Sweden)

    Jan Kučera

    2017-01-01

    Full Text Available Hypoxia is involved in the regulation of stem cell fate, and hypoxia-inducible factor 1 (HIF-1 is the master regulator of hypoxic response. Here, we focus on the effect of hypoxia on intracellular signaling pathways responsible for mouse embryonic stem (ES cell maintenance. We employed wild-type and HIF-1α-deficient ES cells to investigate hypoxic response in the ERK, Akt, and STAT3 pathways. Cultivation in 1% O2 for 24 h resulted in the strong dephosphorylation of ERK and its upstream kinases and to a lesser extent of Akt in an HIF-1-independent manner, while STAT3 phosphorylation remained unaffected. Downregulation of ERK could not be mimicked either by pharmacologically induced hypoxia or by the overexpression. Dual-specificity phosphatases (DUSP 1, 5, and 6 are hypoxia-sensitive MAPK-specific phosphatases involved in ERK downregulation, and protein phosphatase 2A (PP2A regulates both ERK and Akt. However, combining multiple approaches, we revealed the limited significance of DUSPs and PP2A in the hypoxia-mediated attenuation of ERK signaling. Interestingly, we observed a decreased reactive oxygen species (ROS level in hypoxia and a similar phosphorylation pattern for ERK when the cells were supplemented with glutathione. Therefore, we suggest a potential role for the ROS-dependent attenuation of ERK signaling in hypoxia, without the involvement of HIF-1.

  19. Inhibition of calcium uptake during hypoxia in developing zebrafish is mediated by hypoxia-inducible factor.

    Science.gov (United States)

    Kwong, Raymond W M; Kumai, Yusuke; Tzaneva, Velislava; Azzi, Estelle; Hochhold, Nina; Robertson, Cayleih; Pelster, Bernd; Perry, Steve F

    2016-12-15

    The present study investigated the potential role of hypoxia-inducible factor (HIF) in calcium homeostasis in developing zebrafish (Danio rerio). It was demonstrated that zebrafish raised in hypoxic water (30 mmHg; control, 155 mmHg P O 2 ) until 4 days post-fertilization exhibited a substantial reduction in whole-body Ca 2+ levels and Ca 2+ uptake. Ca 2+ uptake in hypoxia-treated fish did not return to pre-hypoxia (control) levels within 2 h of transfer back to normoxic water. Results from real-time PCR showed that hypoxia decreased the whole-body mRNA expression levels of the epithelial Ca 2+ channel (ecac), but not plasma membrane Ca 2+ -ATPase (pmca2) or Na + /Ca 2+ -exchanger (ncx1b). Whole-mount in situ hybridization revealed that the number of ecac-expressing ionocytes was reduced in fish raised in hypoxic water. These findings suggested that hypoxic treatment suppressed the expression of ecac, thereby reducing Ca 2+ influx. To further evaluate the potential mechanisms for the effects of hypoxia on Ca 2+ regulation, a functional gene knockdown approach was employed to prevent the expression of HIF-1αb during hypoxic treatment. Consistent with a role for HIF-1αb in regulating Ca 2+ balance during hypoxia, the results demonstrated that the reduction of Ca 2+ uptake associated with hypoxic exposure was not observed in fish experiencing HIF-1αb knockdown. Additionally, the effects of hypoxia on reducing the number of ecac-expressing ionocytes was less pronounced in HIF-1αb-deficient fish. Overall, the current study revealed that hypoxic exposure inhibited Ca 2+ uptake in developing zebrafish, probably owing to HIF-1αb-mediated suppression of ecac expression. © 2016. Published by The Company of Biologists Ltd.

  20. Nutrient-Deprived Retinal Progenitors Proliferate in Response to Hypoxia: Interaction of the HIF-1 and mTOR Pathway

    Directory of Open Access Journals (Sweden)

    Helena Khaliullina

    2016-05-01

    Full Text Available At a cellular level, nutrients are sensed by the mechanistic Target of Rapamycin (mTOR. The response of cells to hypoxia is regulated via action of the oxygen sensor Hypoxia-Inducible Factor 1 (HIF-1. During development, injury and disease, tissues might face conditions of both low nutrient supply and low oxygen, yet it is not clear how cells adapt to both nutrient restriction and hypoxia, or how mTOR and HIF-1 interact in such conditions. Here we explore this question in vivo with respect to cell proliferation using the ciliary marginal zone (CMZ of Xenopus. We found that both nutrient-deprivation and hypoxia cause retinal progenitors to decrease their proliferation, yet when nutrient-deprived progenitors are exposed to hypoxia there is an unexpected rise in cell proliferation. This increase, mediated by HIF-1 signalling, is dependent on glutaminolysis and reactivation of the mTOR pathway. We discuss how these findings in non-transformed tissue may also shed light on the ability of cancer cells in poorly vascularised solid tumours to proliferate.

  1. Notch1 is required for hypoxia-induced proliferation, invasion and chemoresistance of T-cell acute lymphoblastic leukemia cells

    Directory of Open Access Journals (Sweden)

    Zou Jie

    2013-01-01

    Full Text Available Abstract Background Notch1 is a potent regulator known to play an oncogenic role in many malignancies including T-cell acute lymphoblastic leukemia (T-ALL. Tumor hypoxia and increased hypoxia-inducible factor-1α (HIF-1α activity can act as major stimuli for tumor aggressiveness and progression. Although hypoxia-mediated activation of the Notch1 pathway plays an important role in tumor cell survival and invasiveness, the interaction between HIF-1α and Notch1 has not yet been identified in T-ALL. This study was designed to investigate whether hypoxia activates Notch1 signalling through HIF-1α stabilization and to determine the contribution of hypoxia and HIF-1α to proliferation, invasion and chemoresistance in T-ALL. Methods T-ALL cell lines (Jurkat, Sup-T1 transfected with HIF-1α or Notch1 small interference RNA (siRNA were incubated in normoxic or hypoxic conditions. Their potential for proliferation and invasion was measured by WST-8 and transwell assays. Flow cytometry was used to detect apoptosis and assess cell cycle regulation. Expression and regulation of components of the HIF-1α and Notch1 pathways and of genes related to proliferation, invasion and apoptosis were assessed by quantitative real-time PCR or Western blot. Results Hypoxia potentiated Notch1 signalling via stabilization and activation of the transcription factor HIF-1α. Hypoxia/HIF-1α-activated Notch1 signalling altered expression of cell cycle regulatory proteins and accelerated cell proliferation. Hypoxia-induced Notch1 activation increased the expression of matrix metalloproteinase-2 (MMP2 and MMP9, which increased invasiveness. Of greater clinical significance, knockdown of Notch1 prevented the protective effect of hypoxia/HIF-1α against dexamethasone-induced apoptosis. This sensitization correlated with losing the effect of hypoxia/HIF-1α on Bcl-2 and Bcl-xL expression. Conclusions Notch1 signalling is required for hypoxia/HIF-1α-induced proliferation

  2. Expression of hypoxia-inducible factor 1 alpha and its downstream targets in fibroepithelial tumors of the breast

    NARCIS (Netherlands)

    Kuijper, Arno; Groep, P. van der; Wall, E. van der; Diest, P.J. van

    2005-01-01

    INTRODUCTION Hypoxia-inducible factor 1 (HIF-1) alpha and its downstream targets carbonic anhydrase IX (CAIX) and vascular endothelial growth factor (VEGF) are key factors in the survival of proliferating tumor cells in a hypoxic microenvironment. We studied the expression and prognostic relevance

  3. 4-Hydroxyphenylacetic Acid Attenuated Inflammation and Edema via Suppressing HIF-1α in Seawater Aspiration-Induced Lung Injury in Rats

    Science.gov (United States)

    Liu, Zhongyang; Xi, Ronggang; Zhang, Zhiran; Li, Wangping; Liu, Yan; Jin, Faguang; Wang, Xiaobo

    2014-01-01

    4-Hydroxyphenylacetic acid (4-HPA) is an active component of Chinese herb Aster tataricus which had been widely used in China for the treatment of pulmonary diseases. The aim of this study is to investigate the effect of 4-HPA on seawater aspiration-induced lung injury. Pulmonary inflammation and edema were assessed by enzyme-linked immunosorbent assay (ELISA), bronchoalveolar lavage fluid (BALF) white cell count, Evans blue dye analysis, wet to dry weight ratios, and histology study. Hypoxia-inducible factor-1α (HIF-1α) siRNA and permeability assay were used to study the effect of 4-HPA on the production of inflammatory cytokines and monolayer permeability in vitro. The results showed that 4-HPA reduced seawater instillation-induced mortality in rats. In lung tissues, 4-HPA attenuated hypoxia, inflammation, vascular leak, and edema, and decreased HIF-1α protein level. In primary rat alveolar epithelial cells (AEC), 4-HPA decreased hypertonicity- and hypoxia-induced HIF-1α protein levels through inhibiting the activations of protein translational regulators and via promoting HIF-1α protein degradation. In addition, 4-HPA lowered inflammatory cytokines levels through suppressing hypertonicity- and hypoxia-induced HIF-1α in NR8383 macrophages. Moreover, 4-HPA decreased monolayer permeability through suppressing hypertonicity and hypoxia-induced HIF-1α, which was mediated by inhibiting vascular endothelial growth factor (VEGF) in rat lung microvascular endothelial cell line (RLMVEC). In conclusion, 4-HPA attenuated inflammation and edema through suppressing hypertonic and hypoxic induction of HIF-1α in seawater aspiration-induced lung injury in rats. PMID:25050781

  4. Ptpmt1 induced by HIF-2α regulates the proliferation and glucose metabolism in erythroleukemia cells

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Qin-Qin [High Altitude Medicine of Ministry of Chinese Education and Research Center for High Altitude Medicine, Qinghai University, Xining, 810001 (China); Qinghai Provincial People' s Hospital, Xining (China); Xiao, Feng-Jun; Sun, Hui-Yan [Department of Experimental Hematology, Beijing Institute of Radiation Medicine, Beijing, 100850 (China); Shi, Xue-Feng [High Altitude Medicine of Ministry of Chinese Education and Research Center for High Altitude Medicine, Qinghai University, Xining, 810001 (China); Qinghai Provincial People' s Hospital, Xining (China); Wang, Hua; Yang, Yue-Feng; Li, Yu-Xiang [Department of Experimental Hematology, Beijing Institute of Radiation Medicine, Beijing, 100850 (China); Wang, Li-Sheng, E-mail: wangls@bmi.ac.cn [Department of Experimental Hematology, Beijing Institute of Radiation Medicine, Beijing, 100850 (China); Ge, Ri-Li, E-mail: geriligao@hotmail.com [High Altitude Medicine of Ministry of Chinese Education and Research Center for High Altitude Medicine, Qinghai University, Xining, 810001 (China)

    2016-03-18

    Hypoxia provokes metabolism misbalance, mitochondrial dysfunction and oxidative stress in both human and animal cells. However, the mechanisms which hypoxia causes mitochondrial dysfunction and energy metabolism misbalance still remain unclear. In this study, we presented evidence that mitochondrial phosphatase Ptpmt1 is a hypoxia response molecule that regulates cell proliferation, survival and glucose metabolism in human erythroleukemia TF-1 cells. Exposure to hypoxia or DFO treatment results in upregulation of HIF1-α, HIF-2α and Ptpmt1. Only inhibition of HIF-2α by shRNA transduction reduces Ptpmt1 expression in TF-1 cells under hypoxia. Ptpmt1 inhibitor suppresses the growth and induces apoptosis of TF-1 cells. Furthermore, we demonstrated that Ptpmt1 inhibition reduces the Glut1 and Glut3 expression and decreases the glucose consumption in TF-1 cells. In additional, Ptpmt1 knockdown also results in the mitochondrial dysfunction determined by JC1 staining. These results delineate a key role for HIF-2α-induced Ptpmt1 upregulation in proliferation, survival and glucose metabolism of erythroleukemia cells. It is indicated that Ptpmt1 plays important roles in hypoxia-induced cell metabolism and mitochondrial dysfunction. - Highlights: • Hypoxia induces upregulation of HIF-1α, HIF-2α and Ptpmt1; HIF-2a induces Ptpmt1 upregulation in TF-1 cells. • PTPMT-1 inhibition reduces growth and induces apoptosis of TF-1 cells. • PTPMT1 inhibition downregulates Glut-1, Glut-3 expression and reduces glucose consumption.

  5. Hypoxia and Inflammation in Cancer, Focus on HIF and NF-κB

    Directory of Open Access Journals (Sweden)

    Laura D’Ignazio

    2017-05-01

    Full Text Available Cancer is often characterised by the presence of hypoxia and inflammation. Paramount to the mechanisms controlling cellular responses under such stress stimuli, are the transcription factor families of Hypoxia Inducible Factor (HIF and Nuclear Factor of κ-light-chain-enhancer of activated B cells (NF-κB. Although, a detailed understating of how these transcription factors respond to their cognate stimulus is well established, it is now appreciated that HIF and NF-κB undergo extensive crosstalk, in particular in pathological situations such as cancer. Here, we focus on the current knowledge on how HIF is activated by inflammation and how NF-κB is modulated by hypoxia. We summarise the evidence for the possible mechanism behind this activation and how HIF and NF-κB function impacts cancer, focusing on colorectal, breast and lung cancer. We discuss possible new points of therapeutic intervention aiming to harness the current understanding of the HIF-NF-κB crosstalk.

  6. Hypoxia inducible factor 3α plays a critical role in alveolarization and distal epithelial cell differentiation during mouse lung development.

    Directory of Open Access Journals (Sweden)

    Yadi Huang

    Full Text Available Lung development occurs under relative hypoxia and the most important oxygen-sensitive response pathway is driven by Hypoxia Inducible Factors (HIF. HIFs are heterodimeric transcription factors of an oxygen-sensitive subunit, HIFα, and a constitutively expressed subunit, HIF1β. HIF1α and HIF2α, encoded by two separate genes, contribute to the activation of hypoxia inducible genes. A third HIFα gene, HIF3α, is subject to alternative promoter usage and splicing, leading to three major isoforms, HIF3α, NEPAS and IPAS. HIF3α gene products add to the complexity of the hypoxia response as they function as dominant negative inhibitors (IPAS or weak transcriptional activators (HIF3α/NEPAS. Previously, we and others have shown the importance of the Hif1α and Hiffactors in lung development, and here we investigated the role of Hif3α during pulmonary development. Therefore, HIF3α was conditionally expressed in airway epithelial cells during gestation and although HIF3α transgenic mice were born alive and appeared normal, their lungs showed clear abnormalities, including a post-pseudoglandular branching defect and a decreased number of alveoli. The HIF3α expressing lungs displayed reduced numbers of Clara cells, alveolar epithelial type I and type II cells. As a result of HIF3α expression, the level of Hif2α was reduced, but that of Hif1α was not affected. Two regulatory genes, Rarβ, involved in alveologenesis, and Foxp2, a transcriptional repressor of the Clara cell specific Ccsp gene, were significantly upregulated in the HIF3α expressing lungs. In addition, aberrant basal cells were observed distally as determined by the expression of Sox2 and p63. We show that Hif3α binds a conserved HRE site in the Sox2 promoter and weakly transactivated a reporter construct containing the Sox2 promoter region. Moreover, Hif3α affected the expression of genes not typically involved in the hypoxia response, providing evidence for a novel

  7. Effects of HIF-1 inhibition by chetomin on hypoxia-related transcription and radiosensitivity in HT 1080 human fibrosarcoma cells

    International Nuclear Information System (INIS)

    Staab, Adrian; Einsele, Hermann; Flentje, Michael; Vordermark, Dirk; Loeffler, Jürgen; Said, Harun M; Diehlmann, Désirée; Katzer, Astrid; Beyer, Melanie; Fleischer, Markus; Schwab, Franz; Baier, Kurt

    2007-01-01

    Hypoxia-inducible factor-1 (HIF-1) overexpression has been linked to tumor progression and poor prognosis. We investigated whether targeting of HIF-1 using chetomin, a disrupter of the interaction of HIF-1 with the transcriptional coactivator p300, influences the radiosensitivity of hypoxic HT 1080 human fibrosarcoma cells. Optimal dose of chetomin was determined by EGFP-HRE gene reporter assay in stably transfected HT 1080 cells. Cells were assayed for expression of the hypoxia-inducible genes carbonic anhydrase 9 (CA9) and vascular endothelial growth factor (VEGF) by RT-PCR and for clonogenic survival after irradiation with 2, 5 or 10 Gy, under normoxic or hypoxic (0.1% O 2 , 12 h) conditions in the presence or absence of chetomin (150 nM, 12 h, pre-treatment of 4 h). Chetomin treatment significantly reduced CA9 and VEGF mRNA expression in hypoxic cells to 44.4 ± 7.2% and 39.6 ± 16.0%, respectively, of untreated hypoxic controls. Chetomin clearly reduced the modified oxygen enhancement ratio (OER') compared to untreated cells, from 2.02 to 1.27, from 1.86 to 1.22 and from 1.49 to 1.06 at the 50%, 37% and 10% clonogenic survival levels, respectively. HIF-1 inhibition by chetomin effectively reduces hypoxia-dependent transcription and radiosensitizes hypoxic HT 1080 human fibrosarcoma cells in vitro

  8. Protein arginine methyltransferase 5 is an essential component of the hypoxia-inducible factor 1 signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Ji-Hong; Choi, Yong-Joon; Cho, Chung-Hyun [Department of Pharmacology, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul 110-799 (Korea, Republic of); Park, Jong-Wan, E-mail: parkjw@snu.ac.kr [Department of Pharmacology, Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul 110-799 (Korea, Republic of)

    2012-02-10

    Highlights: Black-Right-Pointing-Pointer HIF-1{alpha} is expressed PRMT5-dependently in hypoxic cancer cells. Black-Right-Pointing-Pointer The HIF-1 regulation of hypoxia-induced genes is attenuated in PRMT5-knocked-down cells. Black-Right-Pointing-Pointer The de novo synthesis of HIF-1{alpha} depends on PRMT5. Black-Right-Pointing-Pointer PRMT5 is involved in the HIF-1{alpha} translation initiated by 5 Prime UTR of HIF-1{alpha} mRNA. -- Abstract: Protein arginine methyltransferase 5 (PRMT5) is an enzyme that transfers one or two methyl groups to the arginine residues of histones or non-histone proteins, and that plays critical roles in cellular processes as diverse as receptor signaling and gene expression. Furthermore, PRMT5 is highly expressed in tumors, where it may be associated with tumor growth. Although much research has been conducted on PRMT5, little is known regarding its role in adaption to hypoxia. As hypoxia-inducible factor 1 (HIF-1) is a key player in hypoxic response, we examined the possible involvement of PRMT5 in the HIF-1 signaling pathway. Of the siRNAs targeting PRMT1-8, only PRMT5 siRNA attenuated the hypoxic induction of HIF-1{alpha} in A549 cells, and this result was reproducible in all three cancer cell lines examined. PRMT5 knock-down also repressed the promoter activities and the transcript levels of HIF-1-governed genes. Mechanistically, de novo synthesis of HIF-1{alpha} protein was reduced in PRMT5-knocked-down A549 cells, and this was rescued by PRMT5 restoration. In contrast, HIF-1{alpha} transcription, RNA processing, and protein stability were unaffected by PRMT5 knock-down. Furthermore, PRMT5 was found to be essential for the HIF-1{alpha} translation initiated by the 5 Prime UTR of HIF-1{alpha} mRNA. Given our results and previous reports, we believe that PRMT5 probably promotes tumor growth by stimulating cell proliferation and by participating in the construction of a tumor-favorable microenvironment via HIF-1 activation.

  9. Silibinin inhibits hypoxia-induced HIF-1α-mediated signaling, angiogenesis and lipogenesis in prostate cancer cells: In vitro evidence and in vivo functional imaging and metabolomics.

    Science.gov (United States)

    Deep, Gagan; Kumar, Rahul; Nambiar, Dhanya K; Jain, Anil K; Ramteke, Anand M; Serkova, Natalie J; Agarwal, Chapla; Agarwal, Rajesh

    2017-03-01

    Hypoxia is associated with aggressive phenotype and poor prognosis in prostate cancer (PCa) patients suggesting that PCa growth and progression could be controlled via targeting hypoxia-induced signaling and biological effects. Here, we analyzed silibinin (a natural flavonoid) efficacy to target cell growth, angiogenesis, and metabolic changes in human PCa, LNCaP, and 22Rv1 cells under hypoxic condition. Silibinin treatment inhibited the proliferation, clonogenicity, and endothelial cells tube formation by hypoxic (1% O 2 ) PCa cells. Interestingly, hypoxia promoted a lipogenic phenotype in PCa cells via activating acetyl-Co A carboxylase (ACC) and fatty acid synthase (FASN) that was inhibited by silibinin treatment. Importantly, silibinin treatment strongly decreased hypoxia-induced HIF-1α expression in PCa cells together with a strong reduction in hypoxia-induced NADPH oxidase (NOX) activity. HIF-1α overexpression in LNCaP cells significantly increased the lipid accumulation and NOX activity; however, silibinin treatment reduced HIF-1α expression, lipid levels, clonogenicity, and NOX activity even in HIF-1α overexpressing LNCaP cells. In vivo, silibinin feeding (200 mg/kg body weight) to male nude mice with 22Rv1 tumors, specifically inhibited tumor vascularity (measured by dynamic contrast-enhanced MRI) resulting in tumor growth inhibition without directly inducing necrosis (as revealed by diffusion-weighted MRI). Silibinin feeding did not significantly affect tumor glucose uptake measured by FDG-PET; however, reduced the lipid synthesis measured by quantitative 1 H-NMR metabolomics. IHC analyses of tumor tissues confirmed that silibinin feeding decreased proliferation and angiogenesis as well as reduced HIF-1α, FASN, and ACC levels. Together, these findings further support silibinin usefulness against PCa through inhibiting hypoxia-induced signaling. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  10. Downregulation of a tumor suppressor RECK by hypoxia through recruitment of HDAC1 and HIF-1alpha to reverse HRE site in the promoter.

    Science.gov (United States)

    Lee, Kyung Ju; Lee, Kwang Youl; Lee, You Mie

    2010-05-01

    Reversion-inducing cysteine-rich protein with Kazal motifs (RECK) is a tumor suppressor and the suppression of RECK is induced by Ras or Her-2/neu oncogenes. However, regulation of RECK under hypoxic microenvironment is largely unknown. Here, we identified that hypoxia significantly downregulates RECK mRNA and protein expression using semiquantitative RT-PCR, real-time RT-PCR and western blot analysis. This repression was reversed by the HDAC inhibitor, trichostatin A (TSA) and HIF-1 inhibitor, YC-1. Hypoxia-induced downregulation of RECK was abolished by knockdown of HDAC1 and HIF-1alpha with respective small interfering RNAs (siRNAs), whereas overexpression of HDAC1 and HIF-1alpha suppressed RECK expression similar to the level under hypoxic conditions. Transfection of a deletion mutant of the second reverse HRE (rHRE2, -2345 to -2333) site of RECK promoter completely removed RECK suppression under hypoxia, indicating that the rHRE2 site is responsible for the inhibition of RECK. Chromatin immunoprecipitation and DNA affinity precipitation assays demonstrated that HDAC1 and HIF-1alpha were recruited to the rHRE2 region of RECK promoter under hypoxic conditions, but the treatment of TSA or YC-1 inhibited their binding to the rHRE2 site. Moreover, TSA and YC-1 inhibited hypoxia-induced cancer cell migration, invasion and MMPs secretion. Taken together, we can conclude that hypoxia induces RECK downregulation through the recruitment of HDAC1 and HIF-1alpha to the rHRE2 site in the promoter and the inhibition of hypoxic RECK silencing would be a therapeutic and preventive target for early tumorigenesis. Copyright 2010 Elsevier B.V. All rights reserved.

  11. Identification of small molecule compounds that inhibit the HIF-1 signaling pathway

    Directory of Open Access Journals (Sweden)

    Sun Yi

    2009-12-01

    Full Text Available Abstract Background Hypoxia-inducible factor-1 (HIF-1 is the major hypoxia-regulated transcription factor that regulates cellular responses to low oxygen environments. HIF-1 is composed of two subunits: hypoxia-inducible HIF-1α and constitutively-expressed HIF-1β. During hypoxic conditions, HIF-1α heterodimerizes with HIF-1β and translocates to the nucleus where the HIF-1 complex binds to the hypoxia-response element (HRE and activates expression of target genes implicated in cell growth and survival. HIF-1α protein expression is elevated in many solid tumors, including those of the cervix and brain, where cells that are the greatest distance from blood vessels, and therefore the most hypoxic, express the highest levels of HIF-1α. Therapeutic blockade of the HIF-1 signaling pathway in cancer cells therefore provides an attractive strategy for development of anticancer drugs. To identify small molecule inhibitors of the HIF-1 pathway, we have developed a cell-based reporter gene assay and screened a large compound library by using a quantitative high-throughput screening (qHTS approach. Results The assay is based upon a β-lactamase reporter under the control of a HRE. We have screened approximate 73,000 compounds by qHTS, with each compound tested over a range of seven to fifteen concentrations. After qHTS we have rapidly identified three novel structural series of HIF-1 pathway Inhibitors. Selected compounds in these series were also confirmed as inhibitors in a HRE β-lactamase reporter gene assay induced by low oxygen and in a VEGF secretion assay. Three of the four selected compounds tested showed significant inhibition of hypoxia-induced HIF-1α accumulation by western blot analysis. Conclusion The use of β-lactamase reporter gene assays, in combination with qHTS, enabled the rapid identification and prioritization of inhibitors specific to the hypoxia induced signaling pathway.

  12. Enhanced response to radiotherapy in tumours deficient in the function of hypoxia-inducible factor-1

    International Nuclear Information System (INIS)

    Williams, Kaye J.; Telfer, Brian A.; Xenaki, Dia; Sheridan, Mary R.; Desbaillets, Isabelle; Peters, Hans J.W.; Honess, Davina; Harris, Adrian L.; Dachs, Gabi U.; Kogel, Albert van der; Stratford, Ian J.

    2005-01-01

    Background and purpose: To test the hypothesis that deficiency in expression of the transcription factor, HIF-1, renders tumours more radioresponsive than HIF-1 proficient tumours. Patients and methods: Tumours comprising mouse hepatoma cells lacking HIF-1β (and thereby HIF-1 function) were grown in nude mice and radiation-induced growth delay compared with that seen for wild-type tumours and tumours derived from HIF-1β negative cells where HIF-1 function had been restored. Results: The xenografts that lack HIF-1 activity take longer to establish their growth and are more radioresponsive than both parental xenografts and those with restored HIF-1 function. Pre-treatment of the HIF-1 deficient xenografts with the hypoxic radiosensitizer misonidazole, had little effect on radioresponse. In contrast this treatment radiosensitized the parental xenografts. In spite of this, no difference in oxygenation status was found between the tumour types as measured by Eppendorf O 2 -electrodes and by binding of the hypoxic cell marker NITP. Admixing wild type and HIF-1 deficient cells in the same tumour at ratios of 1 in 10 and 1 in 100 restores the growth of the mixed tumours to that of a 100% HIF-1 proficient cell population. However, when comparing the effects of radiation on the mixed tumours, radioresponsiveness is maintained in those tumours containing the high proportion of HIF-1 deficient cells. Conclusions: The differences in radioresponse do not correlate with tumour oxygenation, suggesting that the hypoxic cells within the HIF-1 deficient tumours do not contribute to the outcome of radiotherapy. Thus, hypoxia impacts on tumour radioresponsiveness not simply because of the physio-chemical mechanism of oxygen with radiation-induced radicals causing damage 'fixation', but also because hypoxia/HIF-1 promotes expression of genes that allow tumour cells to survive under these adverse conditions. Further, the results from the cell mixing experiments uncouple the growth

  13. Reciprocal Regulation of Hypoxia-Inducible Factor 2α and GLI1 Expression Associated With the Radioresistance of Renal Cell Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jiancheng [Department of Urology, First Affiliated Hospital of Medical School, Xi' an Jiaotong University, Xi' an (China); Department of Urology, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Wu, Kaijie [Department of Urology, First Affiliated Hospital of Medical School, Xi' an Jiaotong University, Xi' an (China); Gao, Dexuan [Department of Urology, Shandong Provincial Hospital affiliated with Shandong University, Ji' nan (China); Zhu, Guodong; Wu, Dapeng; Wang, Xinyang; Chen, Yule; Du, Yuefeng; Song, Wenbin; Ma, Zhenkun [Department of Urology, First Affiliated Hospital of Medical School, Xi' an Jiaotong University, Xi' an (China); Authement, Craig; Saha, Debabrata [Department of Urology, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Hsieh, Jer-Tsong, E-mail: jt.hsieh@utsouthwestern.edu [Department of Urology, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); He, Dalin, E-mail: dalinhe@yahoo.com [Department of Urology, First Affiliated Hospital of Medical School, Xi' an Jiaotong University, Xi' an (China)

    2014-11-15

    Purpose: Renal cell carcinoma (RCC) is often considered a radioresistant tumor, but the molecular mechanism underlying its radioresistance is poorly understood. This study explored the roles of hypoxia-inducible factor 2α (HIF2α) and sonic hedgehog (SHH)-GLI1 signaling in mediating the radioresistance of RCC cells and to unveil the interaction between these 2 signaling pathways. Methods and Materials: The activities of SHH-GLI1 signaling pathway under normoxia and hypoxia in RCC cells were examined by real-time polymerase chain reaction, Western blot, and luciferase reporter assay. The expression of HIF2α and GLI1 in RCC patients was examined by immunohistochemistry, and their correlation was analyzed. Furthermore, RCC cells were treated with HIF2α-specific shRNA (sh-HIF2α), GLI1 inhibitor GANT61, or a combination to determine the effect of ionizing radiation (IR) on RCC cells based on clonogenic assay and double-strand break repair assay. Results: RCC cells exhibited elevated SHH-GLI1 activities under hypoxia, which was mediated by HIF2α. Hypoxia induced GLI1 activation through SMO-independent pathways that could be ablated by PI3K inhibitor or MEK inhibitor. Remarkably, the SHH-GLI1 pathway also upregulated HIF2α expression in normoxia. Apparently, there was a positive correlation between HIF2α and GLI1 expression in RCC patients. The combination of sh-HIF2α and GLI1 inhibitor significantly sensitized RCC cells to IR. Conclusions: Cross-talk between the HIF2α and SHH-GLI1 pathways was demonstrated in RCC. Cotargeting these 2 pathways, significantly sensitizing RCC cells to IR, provides a novel strategy for RCC treatment.

  14. Hypoxic regulation of β-1,3-glucuronyltransferase 1 expression in nucleus pulposus cells of the rat intervertebral disc: role of hypoxia-inducible factor proteins.

    Science.gov (United States)

    Gogate, Shilpa S; Nasser, Rena; Shapiro, Irving M; Risbud, Makarand V

    2011-07-01

    To determine whether hypoxia and hypoxia-inducible factor (HIF) proteins regulate expression of β-1,3-glucuronyltransferase 1 (GlcAT-1), a key enzyme in glycosaminoglycan synthesis in nucleus pulposus cells. Real-time reverse transcriptase-polymerase chain reaction and Western blotting were used to measure GlcAT-1 expression. Transfections were performed to determine the effect of HIF-1α and HIF-2α on GlcAT-1 promoter activity. Under hypoxic conditions there was an increase in GlcAT-1 expression; a significant increase in promoter activity was seen both in nucleus pulposus cells and in N1511 chondrocytes. We investigated whether HIF controlled GlcAT-1 expression. Suppression of HIF-1α and HIF-2α induced GlcAT-1 promoter activity and expression only in nucleus pulposus cells. Transfection with CA-HIF-1α as well as with CA-HIF-2α suppressed GlcAT-1 promoter activity only in nucleus pulposus cells, suggesting a cell type-specific regulation. Site-directed mutagenesis and deletion constructs were used to further confirm the suppressive effect of HIFs on GlcAT-1 promoter function in nucleus pulposus cells. Although it was evident that interaction of HIF with hypoxia-responsive elements resulted in suppression of basal promoter activity, it was not necessary for transcriptional suppression. This result suggested both a direct and an indirect mode of regulation, possibly through recruitment of a HIF-dependent repressor. Finally, we showed that hypoxic expression of GlcAT-1 was also partially dependent on MAPK signaling. These studies demonstrate that hypoxia regulates GlcAT-1 expression through a signaling network comprising both activator and suppressor molecules, and that this regulation is unique to nucleus pulposus cells. Copyright © 2011 by the American College of Rheumatology.

  15. Stanniocalcin-2 is a HIF-1 target gene that promotes cell proliferation in hypoxia

    Energy Technology Data Exchange (ETDEWEB)

    Law, Alice Y.S. [Department of Biology, Hong Kong Baptist University, Kowloon Tong (Hong Kong); Wong, Chris K.C., E-mail: ckcwong@hkbu.edu.hk [Department of Biology, Hong Kong Baptist University, Kowloon Tong (Hong Kong)

    2010-02-01

    Stanniocalcin-2 (STC2), the paralog of STC1, has been suggested as a novel target of oxidative stress response to protect cells from apoptosis. The expression of STC2 has been reported to be highly correlated with human cancer development. In this study, we reported that STC2 is a HIF-1 target gene and is involved in the regulation of cell proliferation. STC2 was shown to be up-regulated in different breast and ovarian cancer cells, following exposure to hypoxia. Using ovarian cancer cells (SKOV3), the underlying mechanism of HIF-1 mediated STC2 gene transactivation was characterized. Hypoxia-induced STC2 expression was found to be HIF-1{alpha} dependent and required the recruitment of p300 and HDAC7. Using STC2 promoter deletion constructs and site-directed mutagenesis, two authentic consensus HIF-1 binding sites were identified. Under hypoxic condition, the silencing of STC2 reduced while the overexpression of STC2 increased the levels of phosphorylated retinoblastoma and cyclin D in both SKOV3 and MCF7 cells. The change in cell cycle proteins correlated with the data of the serial cell counts. The results indicated that cell proliferation was reduced in STC2-silenced cells but was increased in STC2-overexpressing hypoxic cells. Solid tumor progression is usually associated with hypoxia. The identification and functional analysis of STC2 up-regulation by hypoxia, a feature of the tumor microenvironment, sheds light on a possible role for STC2 in tumors.

  16. NEU3 sialidase is activated under hypoxia and protects skeletal muscle cells from apoptosis through the activation of the epidermal growth factor receptor signaling pathway and the hypoxia-inducible factor (HIF)-1α.

    Science.gov (United States)

    Scaringi, Raffaella; Piccoli, Marco; Papini, Nadia; Cirillo, Federica; Conforti, Erika; Bergante, Sonia; Tringali, Cristina; Garatti, Andrea; Gelfi, Cecilia; Venerando, Bruno; Menicanti, Lorenzo; Tettamanti, Guido; Anastasia, Luigi

    2013-02-01

    NEU3 sialidase, a key enzyme in ganglioside metabolism, is activated under hypoxic conditions in cultured skeletal muscle cells (C2C12). NEU3 up-regulation stimulates the EGF receptor signaling pathway, which in turn activates the hypoxia-inducible factor (HIF-1α), resulting in a final increase of cell survival and proliferation. In the same cells, stable overexpression of sialidase NEU3 significantly enhances cell resistance to hypoxia, whereas stable silencing of the enzyme renders cells more susceptible to apoptosis. These data support the working hypothesis of a physiological role played by NEU3 sialidase in protecting cells from hypoxic stress and may suggest new directions in the development of therapeutic strategies against ischemic diseases, particularly of the cerebro-cardiovascular system.

  17. Radiosensitive effect of hypoxia-inducible factor 1α inhibitor YC-1 on hypoxic glioma SHG44 cell line

    International Nuclear Information System (INIS)

    Guo Xinwei; Lu Xueguan; Tong Liumei; Zong Tianzhou; Chen Liesong

    2011-01-01

    Objective: To investigate the radiosensitive effect of hypoxia-inducible factor 1α (HIF-1α) inhibitor YC-1 on hypoxic glioma SHG44 cell line and its related mechanism. Methods: Glioma SHG44 cell line was cultured in normoxic (20% O 2 ), continuous hypoxia (1% O 2 ) for 12 h and 24 h, continuous hypoxia plus YC-1 was performed for 12 h and 24 h, respectively. The expression of HIF-1α was assessed by Western blot. The radiosensitivity was evaluated by the survival curve, and the sublethal damage repair (SLDR) ability was measured by dose-fraction experiment. Results: HIF-1α protein levels of glioma SHG44 cells were significantly increased after hypoxic cultures for 12 h and 24 h than those of the corresponding cells cultured in normoxic, while the radiosensitivity was lower. The OER (oxygen-enhancement ratio) of SHG44 cells in hypoxia for 12 h and 24 h were 1.22 and 1.37, respectively. By the further statistical analysis it was found that SLDR ability of glioma SHG44 was increased at hypoxia, and when irradiation was carried one at the interval of 8, 10, 12 h it was statistically significant (P<0.05). HIF-1α protein levels of glioma SHG44 cells cultured in hypoxia plus YC-1 for 12 h and 24 h were decreased significantly compared to the corresponding cells cultured in hypoxia only, while the radiosensitivity was significantly increased. the EF (enhancement factor) of YC-1 for glioma SHG44 cells at hypoxia for 12 h and 24 h was 1.27. By the further statistical analysis it was also found that SLDR ability was decreased significantly for hypoxic SHG44 cells which was co-cultured with YC-1, and at the interval of 8, 10, 12 h irradiation was statistically significant (P<0.05). Conclusion: YC-1 can increase the radiosensitivity of hypoxic glioma SHG44 cell line, and its mechanism is related to SLDR inhibited by YC-1. (authors)

  18. The Critical Impact of HIF-1α on Gastric Cancer Biology

    Energy Technology Data Exchange (ETDEWEB)

    Kitajima, Yoshihiko, E-mail: kitajiy@esaga.hosp.go.jp [Department of Surgery, Saga University Faculty of Medicine, Saga 849-8501 (Japan); Department of Surgery, NHO Higashisaga Hospital, Saga 849-0101 (Japan); Miyazaki, Kohji [Saga University Faculty of Medicine, Saga 849-8501 (Japan)

    2013-01-10

    Hypoxia inducible factor-1 (HIF-1) monitors the cellular response to the oxygen levels in solid tumors. Under hypoxia conditions, HIF-1α protein is stabilized and forms a heterodimer with the HIF-1β subunit. The HIF-1 complex activates the transcription of numerous target genes in order to adapt the hypoxic environment in human cancer cells. In gastric cancer patients, HIF-1α activation following extended hypoxia strongly correlates with an aggressive tumor phenotype and a poor prognosis. HIF-1α activation has been also reported to occur via hypoxia-independent mechanisms such as PI3K/AKT/mTOR signaling and ROS production. This article argues for the critical roles of HIF-1α in glucose metabolism, carcinogenesis, angiogenesis, invasion, metastasis, cell survival and chemoresistance, focusing on gastric cancer.

  19. Hypoxia-inducible factor 1 alpha expression increases during colorectal carcinogenesis and tumor progression

    International Nuclear Information System (INIS)

    Simiantonaki, Nektaria; Taxeidis, Marios; Jayasinghe, Caren; Kurzik-Dumke, Ursula; Kirkpatrick, Charles James

    2008-01-01

    Hypoxia-inducible factor 1 alpha (HIF-1α) is involved in processes promoting carcinogenesis of many tumors. However, its role in the development of colorectal cancer is unknown. To investigate the significance of HIF-1α during colorectal carcinogenesis and progression we examined its expression in precursor lesions constituting the conventional and serrated pathways, as well as in non-metastatic and metastatic adenocarcinomas. Immunohistochemistry and Western blot is used to analyse HIF-1α expression in normal colonic mucosa, hyperplastic polyps (HPP), sessile serrated adenomas (SSA), low-grade (TA-LGD) and high-grade (TA-HGD) traditional adenomas as well as in non-metastatic and metastatic colorectal adenocarcinomas. Eight colorectal carcinoma cell lines are tested for their HIF-1α inducibility after lipopolysaccharide (LPS) stimulation using western blot and immunocytochemistry. In normal mucosa, HPP and TA-LGD HIF-1α was not expressed. In contast, perinuclear protein accumulation and nuclear expression of HIF-1α were shown in half of the examined SSA and TA-HGD. In all investigated colorectal carcinomas a significant nuclear HIF-1α overexpression compared to the premalignant lesions was observed but a significant correlation with the metastatic status was not found. Nuclear HIF-1α expression was strongly accumulated in perinecrotic regions. In these cases HIF-1α activation was seen in viable cohesive tumor epithelia surrounding necrosis and in dissociated tumor cells, which subsequently die. Enhanced distribution of HIF-1α was also seen in periiflammatory regions. In additional in vitro studies, treatment of diverse colorectal carcinoma cell lines with the potent pro-inflammatory factor lipopolysaccharide (LPS) led to HIF-1α expression and nuclear translocation. We conclude that HIF-1α expression occurs in early stages of colorectal carcinogenesis and achieves a maximum in the invasive stage independent of the metastatic status. Perinecrotic

  20. Hypoxia-inducible factor 1 regulates heat and cold pain sensitivity and persistence.

    Science.gov (United States)

    Kanngiesser, Maike; Mair, Norbert; Lim, Hee-Young; Zschiebsch, Katja; Blees, Johanna; Häussler, Annett; Brüne, Bernhard; Ferreiròs, Nerea; Kress, Michaela; Tegeder, Irmgard

    2014-06-01

    The present study assessed the functions of the transcription factor hypoxia-inducible factor (HIF) in sensory neurons in models of acute, inflammatory, ischemic, and neuropathic pain. The alpha subunit, HIF1α, was specifically deleted in neurons of the dorsal root ganglia by mating HIF1α(fl/fl) mice with SNScre mice. SNS-HIF1α(-/-) mice were more sensitive to noxious heat and cold pain stimulation than were HIF1α(fl/fl) control mice. They also showed heightened first-phase nociceptive responses in the formalin and capsaicin tests with increased numbers of cFos-positive neurons in the dorsal horn, and intensified hyperalgesia in early phases after paw inflammation and hind limb ischemia/reperfusion. The behavioral cold and heat pain hypersensitivity was explained by increased calcium fluxes after transient receptor potential channel activation in primary sensory neurons of SNS-HIF1α(-/-) mice and lowered electrical activation thresholds of sensory fibers. SNS-HIF1α(-/-) mice however, developed less neuropathic pain after sciatic nerve injury, which was associated with an abrogation of HIF1-mediated gene up-regulation. The results suggest that HIF1α is protective in terms of acute heat and cold pain but in case of ongoing activation in injured neurons, it may promote the development of neuropathic pain. The duality of HIF1 in pain regulation may have an impact on the side effects of drugs targeting HIF1, which are being developed, for example, as anticancer agents. Specifically, in patients with cancer neuropathy, however, temporary HIF1 inhibition might provide a welcome combination of growth and pain reduction.

  1. Loss of Hif-2α Rescues the Hif-1α Deletion Phenotype of Neonatal Respiratory Distress In Mice.

    Directory of Open Access Journals (Sweden)

    Yogesh Saini

    Full Text Available Hypoxia is a state of decreased oxygen reaching the tissues of the body. During prenatal development, the fetus experiences localized occurrences of hypoxia that are essential for proper organogenesis and survival. The response to decreased oxygen availability is primarily regulated by hypoxia-inducible factors (HIFs, a family of transcription factors that modulate the expression of key genes involved in glycolysis, angiogenesis, and erythropoiesis. HIF-1α and HIF-2α, two key isoforms, are important in embryonic development, and likely are involved in lung morphogenesis. We have recently shown that the inducible loss of Hif-1α in lung epithelium starting at E4.5 leads to death within an hour of parturition, with symptoms similar to neonatal respiratory distress syndrome (RDS. In addition to Hif-1α, Hif-2α is also expressed in the developing lung, although the overlapping roles of Hif-1α and Hif-2α in this context are not fully understood. To further investigate the independent role of Hif-2α in lung epithelium and its ability to alter Hif-1α-mediated lung maturation, we generated two additional lung-specific inducible Hif-α knockout models (Hif-2α and Hif-1α+Hif-2α. The intrauterine loss of Hif-2α in the lungs does not lead to decreased viability or observable phenotypic changes in the lung. More interestingly, survivability observed after the loss of both Hif-1α and Hif-2α suggests that the loss of Hif-2α is capable of rescuing the neonatal RDS phenotype seen in Hif-1α-deficient pups. Microarray analyses of lung tissue from these three genotypes identified several factors, such as Scd1, Retlnγ, and Il-1r2, which are differentially regulated by the two HIF-α isoforms. Moreover, network analysis suggests that modulation of hormone-mediated, NF-κB, C/EBPα, and c-MYC signaling are central to HIF-mediated changes in lung development.

  2. Inhibition of hypoxia inducible factor 1 and topoisomerase with acriflavine sensitizes perihilar cholangiocarcinomas to photodynamic therapy.

    Science.gov (United States)

    Weijer, Ruud; Broekgaarden, Mans; Krekorian, Massis; Alles, Lindy K; van Wijk, Albert C; Mackaaij, Claire; Verheij, Joanne; van der Wal, Allard C; van Gulik, Thomas M; Storm, Gert; Heger, Michal

    2016-01-19

    Photodynamic therapy (PDT) induces tumor cell death by oxidative stress and hypoxia but also survival signaling through activation of hypoxia-inducible factor 1 (HIF-1). Since perihilar cholangiocarcinomas are relatively recalcitrant to PDT, the aims were to (1) determine the expression levels of HIF-1-associated proteins in human perihilar cholangiocarcinomas, (2) investigate the role of HIF-1 in PDT-treated human perihilar cholangiocarcinoma cells, and (3) determine whether HIF-1 inhibition reduces survival signaling and enhances PDT efficacy. Increased expression of VEGF, CD105, CD31/Ki-67, and GLUT-1 was confirmed in human perihilar cholangiocarcinomas. PDT with liposome-delivered zinc phthalocyanine caused HIF-1α stabilization in SK-ChA-1 cells and increased transcription of HIF-1α downstream genes. Acriflavine was taken up by SK-ChA-1 cells and translocated to the nucleus under hypoxic conditions. Importantly, pretreatment of SK-ChA-1 cells with acriflavine enhanced PDT efficacy via inhibition of HIF-1 and topoisomerases I and II. The expression of VEGF, CD105, CD31/Ki-67, and GLUT-1 was determined by immunohistochemistry in human perihilar cholangiocarcinomas. In addition, the response of human perihilar cholangiocarcinoma (SK-ChA-1) cells to PDT with liposome-delivered zinc phthalocyanine was investigated under both normoxic and hypoxic conditions. Acriflavine, a HIF-1α/HIF-1β dimerization inhibitor and a potential dual topoisomerase I/II inhibitor, was evaluated for its adjuvant effect on PDT efficacy. HIF-1, which is activated in human hilar cholangiocarcinomas, contributes to tumor cell survival following PDT in vitro. Combining PDT with acriflavine pretreatment improves PDT efficacy in cultured cells and therefore warrants further preclinical validation for therapy-recalcitrant perihilar cholangiocarcinomas.

  3. Hypoxia Inducible Factor 1α Promotes Endogenous Adaptive Response in Rat Model of Chronic Cerebral Hypoperfusion

    Directory of Open Access Journals (Sweden)

    Ying Yang

    2017-01-01

    Full Text Available Hypoxia inducible factor 1α (HIF-1α, a pivotal regulator of gene expression in response to hypoxia and ischemia, is now considered to regulate both pro-survival and pro-death responses depending on the duration and severity of the stress. We previously showed that chronic global cerebral hypoperfusion (CCH triggered long-lasting accumulation of HIF-1α protein in the hippocampus of rats. However, the role of the stabilized HIF-1α in CCH is obscure. Here, we knock down endogenous HIF-1α to determine whether and how HIF-1α affects the disease processes and phenotypes of CCH. Lentivirus expressing HIF-1α small hairpin RNA was injected into the bilateral hippocampus and bilateral ventricles to knock down HIF-1α gene expression in the hippocampus and other brain areas. Permanent bilateral common carotid artery occlusions, known as 2-vessel occlusions (2VOs, were used to induce CCH in rats. Angiogenesis, oxidative stress, histopathological changes of the brain, and cognitive function were tested. Knockdown of HIF-1α prior to 2VO significantly exacerbates the impairment of learning and memory after four weeks of CCH. Mechanically, reduced cerebral angiogenesis, increased oxidative damage, and increased density of astrocytes and microglia in the cortex and some subregions of hippocampus are also shown after four weeks of CCH. Furthermore, HIF-1α knockdown also disrupts upregulation of regulated downstream genes. Our findings suggest that HIF-1α-protects the brain from oxidative stress and inflammation response in the disease process of CCH. Accumulated HIF-1α during CCH mediates endogenous adaptive processes to defend against more severe hypoperfusion injury of the brain, which may provide a therapeutic benefit.

  4. Expression of N-WASP is regulated by HiF1α through the hypoxia response element in the N-WASP promoter

    Directory of Open Access Journals (Sweden)

    Amrita Salvi

    2017-03-01

    Full Text Available Cancer cell migration and invasion involves temporal and spatial regulation of actin cytoskeleton reorganization, which is regulated by the WASP family of proteins such as N-WASP (Neural- Wiskott Aldrich Syndrome Protein. We have previously shown that expression of N-WASP was increased under hypoxic conditions. In order to characterize the regulation of N-WASP expression, we constructed an N-WASP promoter driven GFP reporter construct, N-WASPpro-GFP. Transfection of N-WASPpro-GFP construct and plasmid expressing HiF1α (Hypoxia Inducible factor 1α enhanced the expression of GFP suggesting that increased expression of N-WASP under hypoxic conditions is mediated by HiF1α. Sequence analysis of the N-WASP promoter revealed the presence of two hypoxia response elements (HREs characterized by the consensus sequence 5′-GCGTG-3′ at -132 bp(HRE1 and at -662 bp(HRE2 relative to transcription start site (TSS. Site-directed mutagenesis of HRE1(-132 but not HRE2(-662 abolished the HiF1α induced activation of N-WASP promoter. Similarly ChIP assay demonstrated that HiF1α bound to HRE1(-132 but not HRE2(-662 under hypoxic condition. MDA-MB-231 cells but not MDA-MB-231KD cells treated with hypoxia mimicking agent, DMOG showed enhanced gelatin degradation. Similarly MDA-MB-231KD(N-WASPpro-N-WASPR cells expressing N-WASPR under the transcriptional regulation of WT N-WASPpro but not MDA-MB-231KD(N-WASPproHRE1-N-WASPR cells expressing N-WASPR under the transcriptional regulation of N-WASPproHRE1 showed enhanced gelatin degradation when treated with DMOG. Thus indicating the importance of N-WASP in hypoxia induced invadopodia formation. Thus, our data demonstrates that hypoxia-induced activation of N-WASP expression is mediated by interaction of HiF1α with the HRE1(-132 and explains the role of N-WASP in hypoxia induced invadopodia formation.

  5. Intermittent Hypoxia Is Associated With High Hypoxia Inducible Factor-1α but Not High Vascular Endothelial Growth Factor Cell Expression in Tumors of Cutaneous Melanoma Patients

    Directory of Open Access Journals (Sweden)

    Isaac Almendros

    2018-04-01

    Full Text Available Epidemiological associations linking between obstructive sleep apnea and poorer solid malignant tumor outcomes have recently emerged. Putative pathways proposed to explain that these associations have included enhanced hypoxia inducible factor (HIF-1α and vascular endothelial growth factor (VEGF cell expression in the tumor and altered immune functions via intermittent hypoxia (IH. Here, we examined relationships between HIF-1α and VEGF expression and nocturnal IH in cutaneous melanoma (CM tumor samples. Prospectively recruited patients with CM tumor samples were included and underwent overnight polygraphy. General clinical features, apnea–hypopnea index (AHI, desaturation index (DI4%, and CM characteristics were recorded. Histochemical assessments of VEGF and HIF-1α were performed, and the percentage of positive cells (0, <25, 25–50, 51–75, >75% was blindly tabulated for VEGF expression, and as 0, 0–5.9, 6.0–10.0, >10.0% for HIF-1α expression, respectively. Cases with HIF-1α expression >6% (high expression were compared with those <6%, and VEGF expression >75% of cells was compared with those with <75%. 376 patients were included. High expression of VEGF and HIF-1α were seen in 88.8 and 4.2% of samples, respectively. High expression of VEGF was only associated with increasing age. However, high expression of HIF-1α was significantly associated with age, Breslow index, AHI, and DI4%. Logistic regression showed that DI4% [OR 1.03 (95% CI: 1.01–1.06] and Breslow index [OR 1.28 (95% CI: 1.18–1.46], but not AHI, remained independently associated with the presence of high HIF-1α expression. Thus, IH emerges as an independent risk factor for higher HIF-1α expression in CM tumors and is inferentially linked to worse clinical CM prognostic indicators.

  6. Toll-like Receptor 3 Regulates Angiogenesis and Apoptosis in Prostate Cancer Cell Lines through Hypoxia-Inducible Factor 1α

    Directory of Open Access Journals (Sweden)

    Alessio Paone

    2010-07-01

    Full Text Available Toll-like receptors (TLRs recognize microbial/viral-derived components that trigger innate immune response and conflicting data implicate TLR agonists in cancer, either as protumor or antitumor agents. We previously demonstrated that TLR3 activation mediated by its agonist poly(I:C induces antitumor signaling, leading to apoptosis of prostate cancer cells LNCaP and PC3 with much more efficiency in the former than in the second more aggressive line. The transcription factor hypoxia-induciblefactor 1 (HIF-1regulates several cellular processes, includingapoptosis, in response to hypoxia and to other stimuli also in normoxic conditions. Here we describe a novel protumor machinery triggered by TLR3 activation in PC3 cells consisting of increased expression of the specific 1.3 isoform of HIF-1α and nuclear accumulation of HIF-1 complex in normoxia, resulting in reduced apoptosis and in secretion of functional vascular endothelial growth factor (VEGF. Moreover, we report that, in the less aggressive LNCaP cells, TLR3 activation fails to induce nuclear accumulation of HIF-1α. However, the transfection of 1.3 isoform of hif-1α in LNCaP cells allows poly(I:CI-induced HIF-1 activation, resulting in apoptosis protection and VEGF secretion. Altogether, our findings demonstrate that differences in the basal level of HIF-1α expression in different prostate cancer cell lines underlie their differential response to TLR3 activation, suggesting a correlation between different stages of malignancy, hypoxic gene expression, and beneficial responsiveness to TLR agonists.

  7. SCF, regulated by HIF-1α, promotes pancreatic ductal adenocarcinoma cell progression.

    Directory of Open Access Journals (Sweden)

    Chuntao Gao

    Full Text Available Stem cell factor (SCF and hypoxia-inducible factor-1α (HIF-1α both have important functions in pancreatic ductal adenocarcinoma (PDAC. This study aims to analyze the expression and clinicopathological significance of SCF and HIF-1α in PDAC specimens and explore the molecular mechanism at PDAC cells in vitro and in vivo. We showed that the expression of SCF was significantly correlated with HIF-1α expression via Western blot, PCR, chromatin immunoprecipitation (ChIP assay, and luciferase assay analysis. The SCF level was also correlated with lymph node metastasis and the pathological tumor node metastasis (pTNM stage in PDAC samples. The SCF higher-expression group had significantly lower survival rates than the SCF lower-expression group (p<0.05. Hypoxia up-regulated the expression of SCF through the hypoxia-inducible factor (HIF-1α in PDAC cells at the protein and RNA levels. When HIF-1α was knocked down by RNA interference, the SCF level decreased significantly. Additionally, ChIP and luciferase results demonstrated that HIF-1α can directly bind to the hypoxia response element (HRE region of the SCF promoter and activate the SCF transcription under hypoxia. The results of colony formation, cell scratch, and transwell migration assay showed that SCF promoted the proliferation and invasion of PANC-1 cells under hypoxia. Furthermore, the down-regulated ability of cell proliferation and invasion following HIF-1α knockdown was rescued by adding exogenous SCF under hypoxia in vitro. Finally, when the HIF-1α expression was inhibited by digoxin, the tumor volume and the SCF level decreased, thereby proving the relationship between HIF-1α and SCF in vivo. In conclusion, SCF is an important factor for the growth of PDAC. In our experiments, we proved that SCF, a downstream gene of HIF-1α, can promote the development of PDAC under hypoxia. Thus, SCF might be a potential therapeutic target for PDAC.

  8. Knockdown of HIF-1α and IL-8 induced apoptosis of hepatocellular carcinoma triggers apoptosis of vascular endothelial cells.

    Science.gov (United States)

    Choi, Sung Hoon; Park, Jun Yong; Kang, Wonseok; Kim, Seung Up; Kim, Do Young; Ahn, Sang Hoon; Ro, Simon Wonsang; Han, Kwang-Hyub

    2016-01-01

    A local hypoxic microenvironment is one of the most important characteristics of solid tumors. Hypoxia inducible factor-1α (HIF-1α) and Interleukin-8 (IL-8) activate tumor survival from hypoxic-induced apoptosis in each pathway. This study aimed to evaluate whether knockdown of HIF-1α and IL-8 induced apoptosis of the hepatocellular carcinoma (HCC) and endothelial cell lines. HCC cell lines were infected with adenovirus-expressing shRNA for HIF-1α and IL-8 and maintained under hypoxic conditions (1% O2, 24 h). The expression levels of HIF-1α and both apoptotic and growth factors were examined by real-time quantitative PCR and western blot. We also investigated apoptosis by TUNEL assay (FACS and Immunofluorescence) and measured the concentration of cytochrome C. Inhibition of HIF-1α and IL-8 up-regulated the expression of apoptotic factors while downregulating anti-apoptotic factors simultaneously. Knockdown of HIF-1α and IL-8 increased the concentration of cytochrome C and enhanced DNA fragmentation in HCC cell lines. Moreover, culture supernatant collected from the knockdown of HIF-1α and IL-8 in HCC cell lines induced apoptosis in human umbilical vein endothelial cells under hypoxia, and the expression of variable apoptotic ligand increased from HCC cell lines, time-dependently. These data suggest that adenovirus-mediated knockdown of HIF-1α and IL-8 induced apoptosis in HCC cells and triggered apoptosis of vascular endothelial cells.

  9. Acetaminophen hepatotoxicity and HIF-1α induction in acetaminophen toxicity in mice occurs without hypoxia

    International Nuclear Information System (INIS)

    Chaudhuri, Shubhra; McCullough, Sandra S.; Hennings, Leah; Letzig, Lynda; Simpson, Pippa M.; Hinson, Jack A.; James, Laura P.

    2011-01-01

    HIF-1α is a nuclear factor important in the transcription of genes controlling angiogenesis including vascular endothelial growth factor (VEGF). Both hypoxia and oxidative stress are known mechanisms for the induction of HIF-1α. Oxidative stress and mitochondrial permeability transition (MPT) are mechanistically important in acetaminophen (APAP) toxicity in the mouse. MPT may occur as a result of oxidative stress and leads to a large increase in oxidative stress. We previously reported the induction of HIF-1α in mice with APAP toxicity and have shown that VEGF is important in hepatocyte regeneration following APAP toxicity. The following study was performed to examine the relative contribution of hypoxia versus oxidative stress to the induction of HIF-1α in APAP toxicity in the mouse. Time course studies using the hypoxia marker pimonidazole showed no staining for pimonidazole at 1 or 2 h in B6C3F1 mice treated with APAP. Staining for pimonidazole was present in the midzonal to periportal regions at 4, 8, 24 and 48 h and no staining was observed in centrilobular hepatocytes, the sites of the toxicity. Subsequent studies with the MPT inhibitor cyclosporine A showed that cyclosporine A (CYC; 10 mg/kg) reduced HIF-1α induction in APAP treated mice at 1 and 4 h and did not inhibit the metabolism of APAP (depletion of hepatic non-protein sulfhydryls and hepatic protein adduct levels). The data suggest that HIF-1α induction in the early stages of APAP toxicity is secondary to oxidative stress via a mechanism involving MPT. In addition, APAP toxicity is not mediated by a hypoxia mechanism.

  10. Hypoxia-inducible factors regulate pluripotency factor expression by ZNF217- and ALKBH5-mediated modulation of RNA methylation in breast cancer cells.

    Science.gov (United States)

    Zhang, Chuanzhao; Zhi, Wanqing Iris; Lu, Haiquan; Samanta, Debangshu; Chen, Ivan; Gabrielson, Edward; Semenza, Gregg L

    2016-10-04

    Exposure of breast cancer cells to hypoxia increases the percentage of breast cancer stem cells (BCSCs), which are required for tumor initiation and metastasis, and this response is dependent on the activity of hypoxia-inducible factors (HIFs). We previously reported that exposure of breast cancer cells to hypoxia induces the ALKBH5-mediated demethylation of N6-methyladenosine (m6A) in NANOG mRNA leading to increased expression of NANOG, which is a pluripotency factor that promotes BCSC specification. Here we report that exposure of breast cancer cells to hypoxia also induces ZNF217-dependent inhibition of m6A methylation of mRNAs encoding NANOG and KLF4, which is another pluripotency factor that mediates BCSC specification. Although hypoxia induced the BCSC phenotype in all breast-cancer cell lines analyzed, it did so through variable induction of pluripotency factors and ALKBH5 or ZNF217. However, in every breast cancer line, the hypoxic induction of pluripotency factor and ALKBH5 or ZNF217 expression was HIF-dependent. Immunohistochemistry revealed that expression of HIF-1α and ALKBH5 was concordant in all human breast cancer biopsies analyzed. ALKBH5 knockdown in MDA-MB-231 breast cancer cells significantly decreased metastasis from breast to lungs in immunodeficient mice. Thus, HIFs stimulate pluripotency factor expression and BCSC specification by negative regulation of RNA methylation.

  11. Up-regulation of hypoxia-inducible factor (HIF)-1α and HIF-target genes in cortical neurons by the novel multifunctional iron chelator anti-Alzheimer drug, M30.

    Science.gov (United States)

    Avramovich-Tirosh, Y; Bar-Am, O; Amit, T; Youdim, M B H; Weinreb, O

    2010-06-01

    Based on a multimodal drug design paradigm, we have synthesized a multifunctional non-toxic, brain permeable iron chelator, M30, possessing the neuroprotective propargylamine moiety of the anti-Parkinsonian drug, rasagiline (Azilect) and antioxidant-iron chelator moiety of an 8-hydroxyquinoline derivative of our iron chelator, VK28. M30 was recently found to confer potential neuroprotective effects in vitro and in various preclinical neurodegenerative models and regulate the levels and processing of the Alzheimer's amyloid precursor protein and its toxic amyloidogenic derivative, Abeta. Here, we show that M30 activates the hypoxia-inducible factor (HIF)-1alpha signaling pathway, thus promoting HIF-1alpha mRNA and protein expression levels, as well as increasing transcription of HIF-1alpha-dependent genes, including vascular endothelial growth factor, erythropoietin, enolase-1, p21 and tyrosine hydroxylase in rat primary cortical cells. In addition, M30 also increased the expression levels of the transcripts of brain derived neurotrophic factor (BDNF) and growth-associated protein-43 (GAP-43). Regarding aspects of relevance to Alzheimer's disease (AD), western blotting analysis of glycogen synthase kinase- 3beta (GSK-3beta) signaling pathway revealed that M30 enhanced the levels of phospho-AKT (Ser473) and phospho- GSK-3beta (Ser9) and attenuated Tau phosphorylation. M30 was also shown to protect cultured cortical neurons against Abeta(25-35) toxicity. All these multimodal pharmacological activities of M30 might be beneficial for its potent efficacy in the prevention and treatment of neurodegenerative conditions, such as Parkinson's disease and AD in which oxidative stress and iron-mediated toxicity are involved.

  12. Hypoxic Culture Promotes Dopaminergic-Neuronal Differentiation of Nasal Olfactory Mucosa Mesenchymal Stem Cells via Upregulation of Hypoxia-Inducible Factor-1α.

    Science.gov (United States)

    Zhuo, Yi; Wang, Lei; Ge, Lite; Li, Xuan; Duan, Da; Teng, Xiaohua; Jiang, Miao; Liu, Kai; Yuan, Ting; Wu, Pei; Wang, Hao; Deng, Yujia; Xie, Huali; Chen, Ping; Xia, Ying; Lu, Ming

    2017-08-01

    Olfactory mucosa mesenchymal stem cells (OM-MSCs) display significant clonogenic activity and may be easily propagated for Parkinson's disease therapies. Methods of inducing OM-MSCs to differentiate into dopaminergic (DAergic) neurons using olfactory ensheathing cells (OECs) are thus an attractive topic of research. We designed a hypoxic induction protocol to generate DAergic neurons from OM-MSCs using a physiological oxygen (O 2 ) level of 3% and OEC-conditioned medium (OCM; HI group). The normal induction (NI) group was cultured in O 2 at ambient air level (21%). The role of hypoxia-inducible factor-1α (HIF-1α) in the differentiation of OM-MSCs under hypoxia was investigated by treating cells with an HIF-1α inhibitor before induction (HIR group). The proportions of β-tubulin- and tyrosine hydroxylase (TH)-positive cells were significantly increased in the HI group compared with the NI and HIR groups, as shown by immunocytochemistry and Western blotting. Furthermore, the level of dopamine was significantly increased in the HI group. A slow outward potassium current was recorded in differentiated cells after 21 d of induction using whole-cell voltage-clamp tests. A hypoxic environment thus promotes OM-MSCs to differentiate into DAergic neurons by increasing the expression of HIF-1α and by activating downstream target gene TH. This study indicated that OCM under hypoxic conditions could significantly upregulate key transcriptional factors involved in the development of DAergic neurons from OM-MSCs, mediated by HIF-1α. Hypoxia promotes DAergic neuronal differentiation of OM-MSCs, and HIF-1α may play an important role in hypoxia-inducible pathways during DAergic lineage specification and differentiation in vitro.

  13. Hypoxia, hypoxia-inducible transcription factor, and macrophages in human atherosclerotic plaques are correlated with intraplaque angiogenesis

    NARCIS (Netherlands)

    Sluimer, Judith C.; Gasc, Jean-Marie; van Wanroij, Job L.; Kisters, Natasja; Groeneweg, Mathijs; Sollewijn Gelpke, Maarten D.; Cleutjens, Jack P.; van den Akker, Luc H.; Corvol, Pierre; Wouters, Bradly G.; Daemen, Mat J.; Bijnens, Ann-Pascale J.

    2008-01-01

    We sought to examine the presence of hypoxia in human carotid atherosclerosis and its association with hypoxia-inducible transcription factor (HIF) and intraplaque angiogenesis. Atherosclerotic plaques develop intraplaque angiogenesis, which is a typical feature of hypoxic tissue and expression of

  14. aHIF but not HIF-1α transcript is a poor prognostic marker in human breast cancer

    International Nuclear Information System (INIS)

    Cayre, Anne; Rossignol, Fabrice; Clottes, Eric; Penault-Llorca, Frédérique

    2003-01-01

    Hypoxia-inducible factor-1α (HIF-1α) is part of a transcriptional factor that regulates genes involved in metabolic and vascular adaptation of tumours to oxygen restriction. A splicing variant lacking exon 14 (sHIF-1α) encodes a truncated protein that competes with the normal HIF-1α protein, decreasing its activity. A natural antisense transcript (aHIF) complementary to the 3'-untranslated region of HIF-1α mRNA was described recently. With a semiquantitative multiplex reverse transcriptase–PCR (RT–PCR) assay, we assessed transcript concentrations of HIF-1α, sHIF-1α and aHIF in 110 patients with invasive breast carcinoma. We found a strong positive association between HIF-1α and sHIF-1α, sHIF-1α and aHIF, and an inverse correlation between HIF-1α /sHIF-1α and aHIF. aHIF transcript expression was associated with poor disease-free survival in univariate (P = 0.0038) and multivariate (P = 0.0016) analyses in this series of high-risk primary breast carcinomas. In our series of breast cancer patients, aHIF, and not HIF-1α transcript, is a marker of poor prognosis

  15. Helicobacter pylori induces vascular endothelial growth factor production in gastric epithelial cells through hypoxia-inducible factor-1α-dependent pathway.

    Science.gov (United States)

    Kang, Min-Jung; Song, Eun-Jung; Kim, Bo-Yeon; Kim, Dong-Jae; Park, Jong-Hwan

    2014-12-01

    Although Helicobacter pylori have been known to induce vascular endothelial growth factor (VEGF) production in gastric epithelial cells, the precise mechanism for cellular signaling is incompletely understood. In this study, we investigated the role of bacterial virulence factor and host cellular signaling in VEGF production of H. pylori-infected gastric epithelial cells. We evaluated production of VEGF, activation of nuclear factor nuclear factor-kappaB (NF-κB) and mitogen-activated protein kinases (MAPKs) and hypoxia-inducible factor-1α (HIF-1α) stabilization in gastric epithelial cells infected with H. pylori WT or isogenic mutants deficient in type IV secretion system (T4SS). H. pylori induced VEGF production in gastric epithelial cells via both T4SS-dependent and T4SS-independent pathways, although T4SS-independent pathway seems to be the dominant signaling. The inhibitor assay implicated that activation of NF-κB and MAPKs is dispensable for H. pylori-induced VEGF production in gastric epithelial cells. H. pylori led to HIF-1α stabilization in gastric epithelial cells independently of T4SS, NF-κB, and MAPKs, which was essential for VEGF production in these cells. N-acetyl-cysteine (NAC), a reactive oxygen species (ROS) inhibitor, treatment impaired H. pylori-induced HIF-1α stabilization and VEGF production in gastric epithelial cells. We defined the important role of ROS-HIF-1α axis in VEGF production of H. pylori-infected gastric epithelial cells, and bacterial T4SS has a minor role in H. pylori-induced VEGF production of gastric epithelial cells. © 2014 John Wiley & Sons Ltd.

  16. Inhibition of Vascular Endothelial Growth Factor A and Hypoxia-Inducible Factor 1α Maximizes the Effects of Radiation in Sarcoma Mouse Models Through Destruction of Tumor Vasculature

    International Nuclear Information System (INIS)

    Lee, Hae-June; Yoon, Changhwan; Park, Do Joong; Kim, Yeo-Jung; Schmidt, Benjamin; Lee, Yoon-Jin; Tap, William D.; Eisinger-Mathason, T.S. Karin; Choy, Edwin; Kirsch, David G.; Simon, M. Celeste

    2015-01-01

    Purpose: To examine the addition of genetic or pharmacologic inhibition of hypoxia-inducible factor 1α (HIF-1α) to radiation therapy (RT) and vascular endothelial growth factor A (VEGF-A) inhibition (ie trimodality therapy) for soft-tissue sarcoma. Methods and Materials: Hypoxia-inducible factor 1α was inhibited using short hairpin RNA or low metronomic doses of doxorubicin, which blocks HIF-1α binding to DNA. Trimodality therapy was examined in a mouse xenograft model and a genetically engineered mouse model of sarcoma, as well as in vitro in tumor endothelial cells (ECs) and 4 sarcoma cell lines. Results: In both mouse models, any monotherapy or bimodality therapy resulted in tumor growth beyond 250 mm 3 within the 12-day treatment period, but trimodality therapy with RT, VEGF-A inhibition, and HIF-1α inhibition kept tumors at <250 mm 3 for up to 30 days. Trimodality therapy on tumors reduced HIF-1α activity as measured by expression of nuclear HIF-1α by 87% to 95% compared with RT alone, and cytoplasmic carbonic anhydrase 9 by 79% to 82%. Trimodality therapy also increased EC-specific apoptosis 2- to 4-fold more than RT alone and reduced microvessel density by 75% to 82%. When tumor ECs were treated in vitro with trimodality therapy under hypoxia, there were significant decreases in proliferation and colony formation and increases in DNA damage (as measured by Comet assay and γH2AX expression) and apoptosis (as measured by cleaved caspase 3 expression). Trimodality therapy had much less pronounced effects when 4 sarcoma cell lines were examined in these same assays. Conclusions: Inhibition of HIF-1α is highly effective when combined with RT and VEGF-A inhibition in blocking sarcoma growth by maximizing DNA damage and apoptosis in tumor ECs, leading to loss of tumor vasculature

  17. Effect of oxygen on cardiac differentiation in mouse iPS cells: role of hypoxia inducible factor-1 and Wnt/beta-catenin signaling.

    Directory of Open Access Journals (Sweden)

    Tanya L Medley

    Full Text Available BACKGROUND: Disturbances in oxygen levels have been found to impair cardiac organogenesis. It is known that stem cells and differentiating cells may respond variably to hypoxic conditions, whereby hypoxia may enhance stem cell pluripotency, while differentiation of multiple cell types can be restricted or enhanced under hypoxia. Here we examined whether HIF-1alpha modulated Wnt signaling affected differentiation of iPS cells into beating cardiomyocytes. OBJECTIVE: We investigated whether transient and sustained hypoxia affects differentiation of cardiomyocytes derived from murine induced pluripotent stem (iPS cells, assessed the involvement of HIF-1alpha (hypoxia-inducible factor-1alpha and the canonical Wnt pathway in this process. METHODS: Embryoid bodies (EBs derived from iPS cells were differentiated into cardiomyocytes and were exposed either to 24 h normoxia or transient hypoxia followed by a further 13 days of normoxic culture. RESULTS: At 14 days of differentiation, 59 ± 2% of normoxic EBs were beating, whilst transient hypoxia abolished beating at 14 days and EBs appeared immature. Hypoxia induced a significant increase in Brachyury and islet-1 mRNA expression, together with reduced troponin C expression. Collectively, these data suggest that transient and sustained hypoxia inhibits maturation of differentiating cardiomyocytes. Compared to normoxia, hypoxia increased HIF-1alpha, Wnt target and ligand genes in EBs, as well as accumulation of HIF-1alpha and beta-catenin in nuclear protein extracts, suggesting involvement of the Wnt/beta-catenin pathway. CONCLUSION: Hypoxia impairs cardiomyocyte differentiation and activates Wnt signaling in undifferentiated iPS cells. Taken together the study suggests that oxygenation levels play a critical role in cardiomyocyte differentiation and suggest that hypoxia may play a role in early cardiogenesis.

  18. Kinetic Investigations of the Role of Factor Inhibiting Hypoxia-inducible Factor (FIH) as an Oxygen Sensor.

    Science.gov (United States)

    Tarhonskaya, Hanna; Hardy, Adam P; Howe, Emily A; Loik, Nikita D; Kramer, Holger B; McCullagh, James S O; Schofield, Christopher J; Flashman, Emily

    2015-08-07

    The hypoxia-inducible factor (HIF) hydroxylases regulate hypoxia sensing in animals. In humans, they comprise three prolyl hydroxylases (PHD1-3 or EGLN1-3) and factor inhibiting HIF (FIH). FIH is an asparaginyl hydroxylase catalyzing post-translational modification of HIF-α, resulting in reduction of HIF-mediated transcription. Like the PHDs, FIH is proposed to have a hypoxia-sensing role in cells, enabling responses to changes in cellular O2 availability. PHD2, the most important human PHD isoform, is proposed to be biochemically/kinetically suited as a hypoxia sensor due to its relatively high sensitivity to changes in O2 concentration and slow reaction with O2. To ascertain whether these parameters are conserved among the HIF hydroxylases, we compared the reactions of FIH and PHD2 with O2. Consistent with previous reports, we found lower Km(app)(O2) values for FIH than for PHD2 with all HIF-derived substrates. Under pre-steady-state conditions, the O2-initiated FIH reaction is significantly faster than that of PHD2. We then investigated the kinetics with respect to O2 of the FIH reaction with ankyrin repeat domain (ARD) substrates. FIH has lower Km(app)(O2) values for the tested ARDs than HIF-α substrates, and pre-steady-state O2-initiated reactions were faster with ARDs than with HIF-α substrates. The results correlate with cellular studies showing that FIH is active at lower O2 concentrations than the PHDs and suggest that competition between HIF-α and ARDs for FIH is likely to be biologically relevant, particularly in hypoxic conditions. The overall results are consistent with the proposal that the kinetic properties of individual oxygenases reflect their biological capacity to act as hypoxia sensors. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. The acquired radioresistance in HeLa cells under conditions mimicking hypoxia was attenuated by a decreased expression of HIF subunit genes induced by RNA interference

    International Nuclear Information System (INIS)

    Doi, Nobutaka; Ogawa, Ryohei; Cui, Zheng-Guo; Morii, Akihiro; Watanabe, Akihiko; Kanayama, Shinji; Yoneda, Yuko; Kondo, Takashi

    2015-01-01

    The cancer cells residing in the hypoxic layer are resistant to radiation and these are ones responsible for cancer recurrence after radiation therapy. One of the reasons why hypoxic cancer cells acquire radioresistance may be attributable to changes in the gene expression profile by the activation of hypoxia inducible factors (HIFs). However, the details underlying this process remain unknown. In this study, we investigated the effects of knockdown of HIF subunit genes to elucidate how HIF subunit genes may be involved in the radioresistance acquired by HeLa cells following exposure to a hypoxia mimic. Interestingly, HIF-1α and HIF-2α seemed mutually complementary for each other when either of them was suppressed. We thus suppressed the expression of both genes simultaneously. To do this, we developed a short hairpin RNA (shRNA) targeting a high homology region between HIF-1α and HIF-2α. It was shown that the expression of the shRNA effectively suppressed the acquisition of radioresistance following the hypoxia mimic. Moreover, it was confirmed that suppression of both subunits resulted in the downregulation of stem cell markers and the suppression of spheroid formation during the hypoxia mimicking-conditions. This shRNA-mediated knockdown method targeting a common region shared by a family of genes may offer a new candidate cancer treatment. - Highlights: • Incubation with CoCl 2 confers radioresistance to HeLa cells. • Both HIF-1α and HIF-2α are involved in the acquisition of radioresistance. • An shRNA to a homology region of HIF-1α and HIF-2α suppressed the radioresistance. • The shRNA decreased cells with stem cell markers and a stem cell phenotype

  20. The acquired radioresistance in HeLa cells under conditions mimicking hypoxia was attenuated by a decreased expression of HIF subunit genes induced by RNA interference

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Nobutaka [Department of Radiological Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194 (Japan); New Products Research & Development, Gene Engineering Division, NIPPON GENE Co., Ltd. (Japan); Ogawa, Ryohei, E-mail: ogawa@med.u-toyama.ac.jp [Department of Radiological Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194 (Japan); Cui, Zheng-Guo [Department of Public Health, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama (Japan); Morii, Akihiro; Watanabe, Akihiko [Department of Urology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama (Japan); Kanayama, Shinji; Yoneda, Yuko [New Products Research & Development, Gene Engineering Division, NIPPON GENE Co., Ltd. (Japan); Kondo, Takashi [Department of Radiological Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194 (Japan)

    2015-05-01

    The cancer cells residing in the hypoxic layer are resistant to radiation and these are ones responsible for cancer recurrence after radiation therapy. One of the reasons why hypoxic cancer cells acquire radioresistance may be attributable to changes in the gene expression profile by the activation of hypoxia inducible factors (HIFs). However, the details underlying this process remain unknown. In this study, we investigated the effects of knockdown of HIF subunit genes to elucidate how HIF subunit genes may be involved in the radioresistance acquired by HeLa cells following exposure to a hypoxia mimic. Interestingly, HIF-1α and HIF-2α seemed mutually complementary for each other when either of them was suppressed. We thus suppressed the expression of both genes simultaneously. To do this, we developed a short hairpin RNA (shRNA) targeting a high homology region between HIF-1α and HIF-2α. It was shown that the expression of the shRNA effectively suppressed the acquisition of radioresistance following the hypoxia mimic. Moreover, it was confirmed that suppression of both subunits resulted in the downregulation of stem cell markers and the suppression of spheroid formation during the hypoxia mimicking-conditions. This shRNA-mediated knockdown method targeting a common region shared by a family of genes may offer a new candidate cancer treatment. - Highlights: • Incubation with CoCl{sub 2} confers radioresistance to HeLa cells. • Both HIF-1α and HIF-2α are involved in the acquisition of radioresistance. • An shRNA to a homology region of HIF-1α and HIF-2α suppressed the radioresistance. • The shRNA decreased cells with stem cell markers and a stem cell phenotype.

  1. Enhancement of the HIF-1α/15-LO/15-HETE axis promotes hypoxia-induced endothelial proliferation in preeclamptic pregnancy.

    Directory of Open Access Journals (Sweden)

    Dandan Yuan

    Full Text Available Preeclampsia (PE is an extremely serious condition in pregnant women and the leading cause of maternal and fetal morbidity and mortality. Despite active research, the etiological factors of this disorder remain elusive. The increased release of 15-hydroxyeicosatetraenoic acid (15-HETE in the placenta of preeclamptic patients has been studied, but its exact role in PE pathogenesis remains unknown. Mounting evidence shows that PE is associated with placental hypoxia, impaired placental angiogenesis, and endothelial dysfunction. In this study, we confirmed the upregulated expression of hypoxia-inducible factor 1α (HIF-1α and 15-lipoxygenase-1/2 (15-LO-1/2 in patients with PE. Production of the arachidonic acid metabolite, 15-HETE, also increased in the preeclamptic placenta, which suggests enhanced activation of the HIF-1α-15-LO-15-HETE axis. Furthermore, this study is the first to show that the umbilical cord of preeclamptic women contains significantly higher serum concentrations of 15-HETE than that of healthy pregnant women. The results also show that expression of 15-LO-1/2 is upregulated in both human umbilical vein endothelial cells (HUVECs collected from preeclamptic women and in those cultured under hypoxic conditions. Exogenous 15-HETE promotes the migration of HUVECs and in vitro tube formation and promotes cell cycle progression from the G0/G1 phase to the G2/M + S phase, whereas the 15-LO inhibitor, NDGA, suppresses these effects. The HIF-1α/15-LO/15-HETE pathway is therefore significantly associated within the pathology of PE.

  2. Hepcidin: A Critical Regulator Of Iron Metabolism During Hypoxia

    Science.gov (United States)

    2011-01-01

    inducible factor (HIF)/hypoxia response element ( HRE ) system, as well as recent evidence indicating that localized adipose hypoxia due to obesity may...mechanisms by which hypoxia affects hepcidin expression, to include a review of the hypoxia inducible factor (HIF)/hypoxia response element ( HRE ) system, as...a battery of genes are induced by the hypoxia inducible factor (HIF)/hypoxia response element ( HRE ) system. The HIF system senses O2 levels through

  3. Expression patterns of the hypoxia-related genes osteopontin, CA9, erythropoietin, VEGF and HIF-1α in human glioma in vitro and in vivo

    International Nuclear Information System (INIS)

    Said, Harun M.; Hagemann, Carsten; Staab, Adrian; Stojic, Jelena; Kuehnel, Siglinde; Vince, Giles H.; Flentje, Michael; Roosen, Klaus; Vordermark, Dirk

    2007-01-01

    Background and purpose: To identify molecular markers of tumor hypoxia and potential therapeutic targets in glioblastoma (GBM), we investigated the hypoxia-related expression of osteopontin (OPN), carbonic anhydrase 9 (CA9), erythropoietin (EPO), vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α (HIF-1α) in vitro in human GBM cell lines and in vivo in human tumor samples of GBM, compared to low-grade astrocytoma (LGA). Materials and methods: Expression of the hypoxia-induced genes OPN, CA9, EPO, VEGF and HIF-1α was analyzed in three GBM cell lines, GaMG, U373 and U251, under in vitro hypoxia (1, 6 or 24 h at 5%, 1% or 0.1% O 2 ) and in tumor samples from two patient groups with LGA and GBM (n = 15 each), at the mRNA level (semiquantitative RT-PCR). Selected conditions and representative tumor samples were also evaluated at the protein level by Western blot. Results: OPN and CA9 mRNA was most consistently upregulated in relation to severity and duration of in vitro hypoxia. In tumor samples, mean expression levels (LGA vs. GBM, normalized to mean expression in normal brain) were 1.71 vs. 4.57 (p < 0.001) for OPN, 1.11 vs. 3.35 (p < 0.001) for CA9, 2.79 vs. 5.28 (not significant, n.s.) for Epo, 1.13 vs. 2.0 (p = 0.007) for VEGF and 0.97 vs. 0.97 (n.s.) for HIF-1α. In tumor samples, GBM showed a particularly strong protein expression of OPN. Conclusions: Among a panel of known hypoxia-inducible genes, OPN and CA9 emerge as most consistently induced by in vitro hypoxia in human GBM cell lines and most specifically expressed in patient GBM tumor tissue, rendering these two genes attractive targets for hypoxia-directed treatment approaches

  4. Chenodeoxycholic Acid Reduces Hypoxia Inducible Factor-1α Protein and Its Target Genes.

    Directory of Open Access Journals (Sweden)

    Yunwon Moon

    Full Text Available This study evaluated HIF-1α inhibitors under different hypoxic conditions, physiological hypoxia (5% O2 and severe hypoxia (0.1% O2. We found that chenodeoxy cholic acid (CDCA reduced the amount of HIF-1α protein only under physiological hypoxia but not under severe hypoxia without decreasing its mRNA level. By using a proteasome inhibitor MG132 and a translation inhibitor cyclohexamide, we showed that CDCA reduced HIF-1α protein by decreasing its translation but not by enhancing its degradation. The following findings indicated that farnesoid X receptor (FXR, a CDCA receptor and its target gene, Small heterodimer partner (SHP are not involved in this effect of CDCA. Distinctly from CDCA, MG132 prevented SHP and an exogenous FXR agonist, GW4064 from reducing HIF-1α protein. Furthermore a FXR antagonist, guggulsterone failed to prevent CDCA from decreasing HIF-1α protein. Furthermore, guggulsterone by itself reduced HIF-1α protein even in the presence of MG132. These findings suggested that CDCA and guggulsterone reduced the translation of HIF-1α in a mechanism which FXR and SHP are not involved. This study reveals novel therapeutic functions of traditional nontoxic drugs, CDCA and guggulsterone, as inhibitors of HIF-1α protein.

  5. HIF2α/EFEMP1 cascade mediates hypoxic effects on breast cancer stem cell hierarchy.

    Science.gov (United States)

    Kwak, Ji-Hye; Lee, Na-Hee; Lee, Hwa-Yong; Hong, In-Sun; Nam, Jeong-Seok

    2016-07-12

    Breast cancer stem cells (BCSCs) have been shown to contribute to tumor growth, metastasis, and recurrence. They are also markedly resistant to conventional cancer treatments, such as chemotherapy and radiation. Recent studies have suggested that hypoxia is one of the prominent micro-environmental factors that increase the self-renewal ability of BCSCs, partially by enhancing CSC phenotypes. Thus, the identification and development of new therapeutic approaches based on targeting the hypoxia-dependent responses in BCSCs is urgent. Through various in vitro studies, we found that hypoxia specifically up-regulates BCSC sphere formation and a subset of CD44+/CD24-/low CSCs. Hypoxia inducible factors 2α (HIF2α) depletion suppressed CSC-like phenotypes and CSC-mediated drug resistance in breast cancer. Furthermore, the stimulatory effects of hypoxia-induced HIF2α on BCSC sphere formation were successfully attenuated by epidermal growth factor-containing fibulin-like extracellular matrix protein 1 (EFEMP1) knockdown. Taken together, these data suggest that HIF2α mediates hypoxia-induced cancer growth/metastasis and that EFEMP1 is a downstream effector of hypoxia-induced HIF2α during breast tumorigenesis.

  6. Induction of the nuclear factor HIF-1α in acetaminophen toxicity: Evidence for oxidative stress

    International Nuclear Information System (INIS)

    James, Laura P.; Donahower, Brian; Burke, Angela S.; McCullough, Sandra; Hinson, Jack A.

    2006-01-01

    Hypoxia inducible factor (HIF) controls the transcription of genes involved in angiogenesis, erythropoiesis, glycolysis, and cell survival. HIF-1α levels are a critical determinant of HIF activity. The induction of HIF-1α was examined in the livers of mice treated with a toxic dose of APAP (300 mg/kg IP) and sacrificed at 1, 2, 4, 8, and 12 h. HIF-1α was induced at 1-12 h and induction occurred prior to the onset of toxicity. Pre-treatment of mice with N-acetylcysteine (1200 mg/kg IP) prevented toxicity and HIF-1α induction. In further studies, hepatocyte suspensions were incubated with APAP (1 mM) in the presence of an oxygen atmosphere. HIF-1α was induced at 1 h, prior to the onset of toxicity. Inclusion of cyclosporine A (10 μM), an inhibitor of mitochondrial permeability transition, oxidative stress, and toxicity, prevented the induction of HIF-1α. Thus, HIF-1α is induced before APAP toxicity and can occur under non-hypoxic conditions. The data suggest a role for oxidative stress in the induction of HIF-1α in APAP toxicity

  7. Expression of hypoxia-inducible factor-1α and cell cycle proteins in invasive breast cancer are estrogen receptor related

    International Nuclear Information System (INIS)

    Bos, Reinhard; Diest, Paul J van; Groep, Petra van der; Shvarts, Avi; Greijer, Astrid E; Wall, Elsken van der

    2004-01-01

    The transcription factor hypoxia-inducible factor-1 (HIF-1) is a key regulator of the cellular response to hypoxia. Previous studies showed that concentrations of its subunit HIF-1α, as a surrogate for HIF-1 activity, are increased during breast carcinogenesis and can independently predict prognosis in breast cancer. During carcinogenesis, the cell cycle is progressively deregulated, and proliferation rate is a strong prognostic factor in breast cancer. In this study we undertook a detailed evaluation of the relationships between HIF-1α and cell cycle-associated proteins. In a representative estrogen receptor (ER) group of 150 breast cancers, the expression of HIF-1α, vascular endothelial growth factor, the ER, HER-2/neu, Ki-67, cyclin A, cyclin D 1 , p21, p53, and Bcl-2 was investigated by immunohistochemistry. High concentrations (5% or more) of HIF-1α were associated with increased proliferation as shown by positive correlations with Ki-67 (P < 0.001) and the late S–G2-phase protein cyclin A (P < 0.001), but not with the G1-phase protein cyclin D 1 . High HIF-1α concentrations were also strongly associated with p53 positivity (P < 0.001) and loss of Bcl-2 expression (P = 0.013). No association was found between p21 and HIF-1α (P = 0.105) in the whole group of patients. However, the subgroup of ER-positive cancers was characterized by a strong positive association between HIF-1α and p21 (P = 0.023), and HIF-1α lacked any relation with proliferation. HIF-1α overexpression is associated with increased proliferation, which might explain the adverse prognostic impact of increased concentrations of HIF-1α in invasive breast cancer. In ER-positive tumors, HIF-1α is associated with p21 but not against proliferation. This shows the importance of further functional analysis to unravel the role of HIF-1 in late cell cycle progression, and the link between HIF-1, p21, and ER

  8. Increased hypoxia-inducible factor-1α in striated muscle of tumor-bearing mice.

    Science.gov (United States)

    Devine, Raymond D; Bicer, Sabahattin; Reiser, Peter J; Wold, Loren E

    2017-06-01

    Cancer cachexia is a progressive wasting disease resulting in significant effects on the quality of life and high mortality. Most studies on cancer cachexia have focused on skeletal muscle; however, the heart is now recognized as a major site of cachexia-related effects. To elucidate possible mechanisms, a proteomic study was performed on the left ventricles of colon-26 (C26) adenocarcinoma tumor-bearing mice. The results revealed several changes in proteins involved in metabolism. An integrated pathway analysis of the results revealed a common mediator in hypoxia-inducible factor-1α (HIF-1α). Work by other laboratories has shown that extensive metabolic restructuring in the C26 mouse model causes changes in gene expression that may be affected directly by HIF-1α, such as glucose metabolic genes. M-mode echocardiography showed progressive decline in heart function by day 19 , exhibited by significantly decreased ejection fraction and fractional shortening, along with posterior wall thickness. Using Western blot analysis, we confirmed that HIF-1α is significantly upregulated in the heart, whereas there were no changes in its regulatory proteins, prolyl hydroxylase domain-containing protein 2 (PHD2) and von Hippel-Lindau protein (VHL). PHD2 requires both oxygen and iron as cofactors for the hydroxylation of HIF-1α, marking it for ubiquination via VHL and subsequent destruction by the proteasome complex. We examined venous blood gas values in the tumor-bearing mice and found significantly lower oxygen concentration compared with control animals in the third week after tumor inoculation. We also examined select skeletal muscles to determine whether they are similarly affected. In the diaphragm, extensor digitorum longus, and soleus, we found significantly increased HIF-1α in tumor-bearing mice, indicating a hypoxic response, not only in the heart, but also in skeletal muscle. These results indicate that HIF-1α may contribute, in part, to the metabolic changes

  9. Polymorphisms in the hypoxia-inducible factor 1 alpha gene in Mexican patients with preeclampsia: A case-control study

    Directory of Open Access Journals (Sweden)

    Nava-Salazar Sonia

    2011-03-01

    Full Text Available Abstract Background Although the etiology of preeclampsia is still unclear, recent work suggests that changes in circulating angiogenic factors play a key role in its pathogenesis. In the trophoblast of women with preeclampsia, hypoxia-inducible factor 1 alpha (HIF-1α is over-expressed, and induces the expression of non-angiogenic factors and inhibitors of trophoblast differentiation. This observation prompted the study of HIF-1α and its relation to preeclampsia. It has been described that the C1772T (P582S and G1790A (A588T polymorphisms of the HIF1A gene have significantly greater transcriptional activity, correlated with an increased expression of their proteins, than the wild-type sequence. In this work, we studied whether either or both HIF1A variants contribute to preeclampsia susceptibility. Results Genomic DNA was isolated from 150 preeclamptic and 105 healthy pregnant women. Exon 12 of the HIF1A gene was amplified by PCR, and the genotypes of HIF1A were determined by DNA sequencing. In preeclamptic women and controls, the frequencies of the T allele for C1772T were 4.3 vs. 4.8%, and the frequencies of the A allele for G1790A were 0.0 vs. 0.5%, respectively. No significant differences were found between groups. Conclusion The frequency of the C1772T and G1790A polymorphisms of the HIF1A gene is very low, and neither polymorphism is associated with the development of preeclampsia in the Mexican population.

  10. 4-Hydroxy estradiol but not 2-hydroxy estradiol induces expression of hypoxia-inducible factor 1α and vascular endothelial growth factor A through phosphatidylinositol 3-kinase/Akt/FRAP pathway in OVCAR-3 and A2780-CP70 human ovarian carcinoma cells

    International Nuclear Information System (INIS)

    Gao Ning; Nester, Rebecca A.; Sarkar, Mohamadi A.

    2004-01-01

    Hypoxia-inducible factor 1 (HIF-1) is a heterodimeric basic helix-loop-helix transcription factor composed of HIF-1α and HIF-1β subunits. HIF-1 expression is induced by hypoxia, growth factors, and activation of oncogenes. HIF-1 activates downstream target genes such as vascular endothelial growth factor A (VEGF-A), which plays an important role in tumor progression and angiogenesis. Estrogen exposure is considered to be the major risk factor for ovarian cancer. Estradiol (E2) is usually metabolized by CYP1A1/1A2 and CYP3A4 to the 2-hydroxy estradiol (2-OHE2) and 4-hydroxy estradiol (4-OHE2) in human liver. Many reports have suggested that the formation of 4-OHE2 is important for mammary carcinogenesis. However, the formation of 2-OHE2 may play an important role in exhibiting anticarcinogenic effects. In the present study, we have demonstrated that one of the catechol estrogen metabolites of E2, 4-OHE2, induces HIF-1α and VEGF-A expression at protein level in two human ovarian cancer cell lines, OVCAR-3 and A2780-CP70 cells, in dose- and time-dependent manners, whereas the other catechol estrogen metabolite of E2, 2-OHE2, does not alter HIF-1α and VEGF-A expression. To explore the mechanism of 4-OHE2-induced HIF-1α and VEGF-A expression, we studied whether phosphatidylinositol 3-kinase (PI3K) or mitogen-activated protein kinase (MAPK) signaling pathways are involved in 4-OHE2-induced HIF-1α and VEGF-A expression. Our findings indicate that PI3K inhibitors, LY294002 and wortmannin, inhibited HIF-1α and VEGF-A expression, whereas MAPK inhibitor, PD98059, did not alter HIF-1α and VEGF-A expression induced by 4-OHE2. 4-OHE2, but not 2-OHE2, also induced Akt phosphorylation at Ser473 in dose- and time-dependent manners, and LY294002 and wortmannin inhibited Akt phosphorylation at Ser473 induced by 4-OHE2. Our results also indicated that the mTOR/FRAP inhibitor, rapamycin, inhibited 4-OHE2-induced HIF-1α and VEGF-A expression. These results suggest that the PI3K

  11. hypoxia-inducible factors activate CD133 promoter through ETS family transcription factors.

    Directory of Open Access Journals (Sweden)

    Shunsuke Ohnishi

    Full Text Available CD133 is a cellular surface protein that has been reported to be a cancer stem cell marker, and thus it is considered to be a potential target for cancer treatment. However, the mechanism regulating CD133 expression is not yet understood. In this study, we analyzed the activity of five putative promoters (P1-P5 of CD133 in human embryonic kidney (HEK 293 cells and colon cancer cell line WiDr, and found that the activity of promoters, particularly of P5, is elevated by overexpression of hypoxia-inducible factors (HIF-1α and HIF-2α. Deletion and mutation analysis identified one of the two E-twenty six (ETS binding sites (EBSs in the P5 region as being essential for its promoter activity induced by HIF-1α and HIF-2α. In addition, a chromatin imunoprecipitation assay demonstrated that HIF-1α and HIF-2α bind to the proximal P5 promoter at the EBSs. The immunoprecipitation assay showed that HIF-1α physically interacts with Elk1; however, HIF-2α did not bind to Elk1 or ETS1. Furthermore, knockdown of both HIF-1α and HIF-2α resulted in a reduction of CD133 expression in WiDr. Taken together, our results revealed that HIF-1α and HIF-2α activate CD133 promoter through ETS proteins.

  12. Adult hematopoietic stem cells lacking Hif-1α self-renew normally

    Science.gov (United States)

    Vukovic, Milica; Sepulveda, Catarina; Subramani, Chithra; Guitart, Amélie V.; Mohr, Jasmine; Allen, Lewis; Panagopoulou, Theano I.; Paris, Jasmin; Lawson, Hannah; Villacreces, Arnaud; Armesilla-Diaz, Alejandro; Gezer, Deniz; Holyoake, Tessa L.; Ratcliffe, Peter J.

    2016-01-01

    The hematopoietic stem cell (HSC) pool is maintained under hypoxic conditions within the bone marrow microenvironment. Cellular responses to hypoxia are largely mediated by the hypoxia-inducible factors, Hif-1 and Hif-2. The oxygen-regulated α subunits of Hif-1 and Hif-2 (namely, Hif-1α and Hif-2α) form dimers with their stably expressed β subunits and control the transcription of downstream hypoxia-responsive genes to facilitate adaptation to low oxygen tension. An initial study concluded that Hif-1α is essential for HSC maintenance, whereby Hif-1α–deficient HSCs lost their ability to self-renew in serial transplantation assays. In another study, we demonstrated that Hif-2α is dispensable for cell-autonomous HSC maintenance, both under steady-state conditions and following transplantation. Given these unexpected findings, we set out to revisit the role of Hif-1α in cell-autonomous HSC functions. Here we demonstrate that inducible acute deletion of Hif-1α has no impact on HSC survival. Notably, unstressed HSCs lacking Hif-1α efficiently self-renew and sustain long-term multilineage hematopoiesis upon serial transplantation. Finally, Hif-1α–deficient HSCs recover normally after hematopoietic injury induced by serial administration of 5-fluorouracil. We therefore conclude that despite the hypoxic nature of the bone marrow microenvironment, Hif-1α is dispensable for cell-autonomous HSC maintenance. PMID:27060169

  13. Correlation of hypoxia inducible factor-1α and vascular endothelium growth factor in rat myocardium during aerobic and anaerobic exercise

    Directory of Open Access Journals (Sweden)

    Rostika Flora

    2012-08-01

    Full Text Available Background: Exercise increases the need for oxygen to generate ATP through oxidative phosphorylation. If the high energy demand during exercise is not balanced by sufficient oxygen supply, hypoxia occurs in skeletal muscle tissue leading to upregulation of hypoxia inducible factor-1α (HIF-1α. The activity of HIF-1α increases the expression of various genes in order to reduce the metabolic dependence on oxygen and to increase oxygen supply to the tissue, e.g., VEGF which plays a role in angiogenesis. In myocardium, it is unclear whether exercise leads to hypoxia and whether HIF-1α and VEGF play a role in the mechanism of hypoxic adaptation. This study aimed to investigate the correlation of HIF-1α and VEGF in heart muscle tissue of rats during aerobic and anaerobic exercise.Methods: A rat treadmill was used with a specific exercise program for 1, 3, 7 and 10 days. The concentrations of HIF-1α and VEGF were measured the myocardium.Results: Both, HIF-1α protein and VEGF were increased (p < 0.05 in the groups with aerobic and anaerobic exercise. Concentrations of HIF-1α were highest on the first day of activity, being higher in the anaerobic than in the aerobic group (156.8 ± 33.1 vs. 116.03 ± 5.66. Likewise, the highest concentration of VEGF in the group with anaerobic exercise occurred on the first day (36.37 ± 2:35, while in the aerobic group, VEGF concentration was highest on day 3 (40.66 ± 1.73. The correlation between the myocardial tissue consentrations of HIF-1α and VEGF is moderate (r = 0.59 in the aerobic group and strong in the anaerobic group (r = 0.69.Conclusion: Aerobic and anaerobic exercise increase HIF-1α and VEGF concentrations in rat myocardium in specific patterns. The anaerobic condition triggers vascularization stronger and obviously earlier than aerobic exercise. (Med J Indones. 2012;21:133-40Keywords: Exercise, HIF-1α, myocardium, VEGF

  14. Stimulating retinal blood vessel protection with hypoxia-inducible factor stabilization: identification of novel small-molecule hydrazones to inhibit hypoxia-inducible factor prolyl hydroxylase (an American Ophthalmological Society thesis).

    Science.gov (United States)

    Sears, Jonathan E; Hoppe, George

    2013-09-01

    To discover novel small molecules that inhibit hypoxia-inducible factor (HIF) prolyl hydroxylase (PHD), a key enzyme that regulates the posttranslational stability and hence activity of HIF. NIH3T3 cell line stably transfected with firefly luciferase under a HIF-1-inducible promoter was used to screen a Chembridge library of 34,000 small molecules of molecular weight 250 to 550 Da. Positive hits were considered at 4.5-fold higher luminescence than control. Selected compounds were validated in vitro. The most effective dose was then used to treat mice expressing firefly luciferase fused to the oxygen-dependent degradation domain (lucODD) in order to determine the location of the receptor for systemic treatment with small-molecule HIF PHD inhibitors. Twenty-three novel small molecules were discovered, the majority of which were hydrazones and hydrazines. Of the 23 compounds, each had different selectivity for expression of erythropoietin or vascular endothelial growth factor, two angiogenic, HIF-regulated gene products. In addition, each showed different selectivity for hepatocytes or kidney, or both or neither, when injected intraperitoneally in an in vivo reporter gene assay. The discovery of multiple small molecules that inhibit HIF PHD identifies new reagents to develop strategies to prevent the degradation of HIF by its selective PHD. These molecules are novel hypoxia mimetics that may provide new strategies to protect retinovasculature from hyperoxia.

  15. Hypoxia regulates the expression and localization of CCAAT/enhancer binding protein α by hypoxia inducible factor-1α in bladder transitional carcinoma cells.

    Science.gov (United States)

    Xue, Mei; Li, Xu; Chen, Wei

    2015-08-01

    Hypoxia inducible factor-1α (HIF-1α) is overexpressed in various types of solid tumor in humans, including bladder cancer. HIF-1α regulates the expression of a series of genes, which are involved in cell proliferation, differentiation, apoptosis, angiogenesis, migration and invasion and represents a potential therapeutic target for the treatment of human cancer. Despite extensive investigation of the effects of HIF-1α in the progression and metastasis of bladder cancer, the possible regulatory mechanisms underlying the effects of HIF-1α on bladder cancer cell proliferation and differentiation remain to be elucidated. It has been suggested that the transcription factor CCAAT/enhancer binding protein α (C/EBPα) acts as a tumor suppressor in several types of cancer cell, which are involved in regulating cell differentiation, proliferation and apoptosis. The present study confirmed that, in bladder cancer cells, the expression and localization of C/EBPα was regulated by hypoxia through an HIF-1α -dependent mechanism, which may be significant in bladder cancer cell proliferation and differentiation. The 5637 and T24 bladder cancer cell lines were incubated under normoxic and hypoxic conditions. The expression levels of HIF-1α and C/EBPα were detected by reverse transcription-quantitative polymerase chain reaction, western blotting and immunofluorescence analysis. The results revealed that, under hypoxic conditions, the protein expression levels of HIF-1α were markedly upregulated, but the mRNA levels were not altered. However, the mRNA and protein levels of C/EBPα were significantly reduced. The present study further analyzed the subcellular localization of C/EBPα, which was markedly decreased in the nuclei under hypoxic conditions. Following HIF-1α small interference RNA silencing of HIF-1α, downregulation of C/EBPα was prevented in the bladder cancer cells cultured under hypoxic conditions. In addition, groups of cells treated with 3-(5'-hydroxymethyl

  16. The 2-oxoglutarate analog 3-oxoglutarate decreases normoxic hypoxia-inducible factor-1α in cancer cells, induces cell death, and reduces tumor xenograft growth

    Directory of Open Access Journals (Sweden)

    Koivunen P

    2016-03-01

    Full Text Available Peppi Koivunen,1 Stuart M Fell,2,3 Wenyun Lu,4 Joshua D Rabinowitz,4 Andrew L Kung,5,6 Susanne Schlisio,2,7 1Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, Oulu Center for Cell-Matrix Research, University of Oulu, Oulu, Finland; 2Ludwig Institute for Cancer Research Ltd, Stockholm, Sweden; 3Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden; 4Department of Chemistry and Integrative Genomics, Princeton University, Princeton, NJ, 5Department of Medical Oncology, Dana Farber Cancer Institute, Harvard Medical School, Boston, MA, 6Department of Pediatrics, Columbia University Medical Center, New York, NY, USA; 7Department of Microbiology and Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden Abstract: The cellular response to hypoxia is primarily regulated by the hypoxia-inducible factors (HIFs. HIF-1α is also a major mediator of tumor physiology, and its abundance is correlated with therapeutic resistance in a broad range of cancers. Accumulation of HIF-1α under hypoxia is mainly controlled by the oxygen-sensing HIF prolyl 4-hydroxylases (EGLNs, also known as PHDs. Here, we identified a high level of normoxic HIF-1α protein in various cancer cell lines. EGLNs require oxygen and 2-oxoglutarate for enzymatic activity. We tested the ability of several cell-permeable 2-oxoglutarate analogs to regulate the abundance of HIF-1α protein. We identified 3-oxoglutarate as a potent regulator of HIF-1α in normoxic conditions. In contrast to 2-oxoglutarate, 3-oxoglutarate decreased the abundance of HIF-1α protein in several cancer cell lines in normoxia and diminished HIF-1α levels independent of EGLN enzymatic activity. Furthermore, we observed that 3-oxoglutarate was detrimental to cancer cell survival. We show that esterified 3-oxoglutarate, in combination with the cancer chemotherapeutic drug vincristine, induces apoptosis and inhibits tumor growth in vitro and in vivo. Our data

  17. Investigating the Regulation and Potential Role of Nonhypoxic Hypoxia-Inducible Factor 1 (HIF-1) in Aromatase Inhibitor Resistant Breast Cancer

    Science.gov (United States)

    2013-10-01

    hypoxia responsive element ( HRE ) to which HIF-1 binds in order to regulate vimentin gene expresson has not been identified. We have currently, analyzed...the vimentin promoter and have identified 2 potential HRE sites, based on sequence (Figure 5). Primers have been designed and ordered, and

  18. Schedule-dependent inhibition of hypoxia-inducible factor-1alpha protein accumulation, angiogenesis, and tumor growth by topotecan in U251-HRE glioblastoma xenografts.

    Science.gov (United States)

    Rapisarda, Annamaria; Zalek, Jessica; Hollingshead, Melinda; Braunschweig, Till; Uranchimeg, Badarch; Bonomi, Carrie A; Borgel, Suzanne D; Carter, John P; Hewitt, Stephen M; Shoemaker, Robert H; Melillo, Giovanni

    2004-10-01

    We have previously shown that topotecan, a topoisomerase I poison, inhibits hypoxia-inducible factor (HIF)-1alpha protein accumulation by a DNA damage-independent mechanism. Here, we report that daily administration of topotecan inhibits HIF-1alpha protein expression in U251-HRE glioblastoma xenografts. Concomitant with HIF-1alpha inhibition, topotecan caused a significant tumor growth inhibition associated with a marked decrease of angiogenesis and expression of HIF-1 target genes in tumor tissue. These results provide a compelling rationale for testing topotecan in clinical trials to target HIF-1 in cancer patients.

  19. Activation of the Hypoxia Inducible Factor 1α Subunit Pathway in Steatotic Liver Contributes to Formation of Cholesterol Gallstones.

    Science.gov (United States)

    Asai, Yoichiro; Yamada, Tetsuya; Tsukita, Sohei; Takahashi, Kei; Maekawa, Masamitsu; Honma, Midori; Ikeda, Masanori; Murakami, Keigo; Munakata, Yuichiro; Shirai, Yuta; Kodama, Shinjiro; Sugisawa, Takashi; Chiba, Yumiko; Kondo, Yasuteru; Kaneko, Keizo; Uno, Kenji; Sawada, Shojiro; Imai, Junta; Nakamura, Yasuhiro; Yamaguchi, Hiroaki; Tanaka, Kozo; Sasano, Hironobu; Mano, Nariyasu; Ueno, Yoshiyuki; Shimosegawa, Tooru; Katagiri, Hideki

    2017-05-01

    Hypoxia-inducible factor 1α subunit (HIF1A) is a transcription factor that controls the cellular response to hypoxia and is activated in hepatocytes of patients with nonalcoholic fatty liver disease (NAFLD). NAFLD increases the risk for cholesterol gallstone disease by unclear mechanisms. We studied the relationship between HIF1A and gallstone formation associated with liver steatosis. We performed studies with mice with inducible disruption of Hif1a in hepatocytes via a Cre adenoviral vector (inducible hepatocyte-selective HIF1A knockout [iH-HIFKO] mice), and mice without disruption of Hif1a (control mice). Mice were fed a diet rich in cholesterol and cholate for 1 or 2 weeks; gallbladders were collected and the number of gallstones was determined. Livers and biliary tissues were analyzed by histology, quantitative reverse-transcription polymerase chain reaction, immunohistochemistry, and immunoblots. We measured concentrations of bile acid, cholesterol, and phospholipid in bile and rates of bile flow. Primary hepatocytes and cholangiocytes were isolated and analyzed. HIF1A was knocked down in Hepa1-6 cells with small interfering RNAs. Liver biopsy samples from patients with NAFLD, with or without gallstones, were analyzed by quantitative reverse-transcription polymerase chain reaction. Control mice fed a diet rich in cholesterol and cholate developed liver steatosis with hypoxia; levels of HIF1A protein were increased in hepatocytes around central veins and 90% of mice developed cholesterol gallstones. Only 20% of the iH-HIFKO mice developed cholesterol gallstones. In iH-HIFKO mice, the biliary lipid concentration was reduced by 36%, compared with control mice, and bile flow was increased by 35%. We observed increased water secretion from hepatocytes into bile canaliculi to mediate these effects, resulting in suppression of cholelithogenesis. Hepatic expression of aquaporin 8 (AQP8) protein was 1.5-fold higher in iH-HIFKO mice than in control mice. Under hypoxic

  20. Inflammatory cytokine tumor necrosis factor α suppresses neuroprotective endogenous erythropoietin from astrocytes mediated by hypoxia-inducible factor-2α.

    Science.gov (United States)

    Nagaya, Yoshiaki; Aoyama, Mineyoshi; Tamura, Tetsuya; Kakita, Hiroki; Kato, Shin; Hida, Hideki; Saitoh, Shinji; Asai, Kiyofumi

    2014-12-01

    Interest in erythropoietin (EPO) as a neuroprotective mediator has grown since it was found that systemically administered EPO is protective in several animal models of disease. However, given that the blood-brain barrier limits EPO entry into the brain, alternative approaches that induce endogenous EPO production in the brain may be more effective clinically and associated with fewer untoward side-effects. Astrocytes are the main source of EPO in the central nervous system. In the present study we investigated the effect of the inflammatory cytokine tumor necrosis factor α (TNFα) on hypoxia-induced upregulation of EPO in rat brain. Hypoxia significantly increased EPO mRNA expression in the brain and kidney, and this increase was suppressed by TNFα in vivo. In cultured astrocytes exposed to hypoxic conditions for 6 and 12 h, TNFα suppressed the hypoxia-induced increase in EPO mRNA expression in a concentration-dependent manner. TNFα inhibition of hypoxia-induced EPO expression was mediated primarily by hypoxia-inducible factor (HIF)-2α rather than HIF-1α. The effects of TNFα in reducing hypoxia-induced upregulation of EPO mRNA expression probably involve destabilization of HIF-2α, which is regulated by the nuclear factor (NF)-κB signaling pathway. TNFα treatment attenuated the protective effects of astrocytes on neurons under hypoxic conditions via EPO signaling. The effective blockade of TNFα signaling may contribute to the maintenance of the neuroprotective effects of EPO even under hypoxic conditions with an inflammatory response. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  1. Ursodeoxycholic acid protects cardiomyocytes against cobalt chloride induced hypoxia by regulating transcriptional mediator of cells stress hypoxia inducible factor 1α and p53 protein.

    Science.gov (United States)

    Mohamed, Anis Syamimi; Hanafi, Noorul Izzati; Sheikh Abdul Kadir, Siti Hamimah; Md Noor, Julina; Abdul Hamid Hasani, Narimah; Ab Rahim, Sharaniza; Siran, Rosfaiizah

    2017-10-01

    In hepatocytes, ursodeoxycholic acid (UDCA) activates cell signalling pathways such as p53, intracellular calcium ([Ca 2+ ] i ), and sphingosine-1-phosphate (S1P)-receptor via Gα i -coupled-receptor. Recently, UDCA has been shown to protect the heart against hypoxia-reoxygenation injury. However, it is not clear whether UDCA cardioprotection against hypoxia acts through a transcriptional mediator of cells stress, HIF-1α and p53. Therefore, in here, we aimed to investigate whether UDCA could protect cardiomyocytes (CMs) against hypoxia by regulating expression of HIF-1α, p53, [Ca 2+ ] i , and S1P-Gα i -coupled-receptor. Cardiomyocytes were isolated from newborn rats (0-2 days), and hypoxia was induced by using cobalt chloride (CoCl 2 ). Cardiomyocytes were treated with UDCA and cotreated with either FTY720 (S1P-receptor agonist) or pertussis toxin (PTX; Gα i inhibitor). Cells were subjected for proliferation assay, beating frequency, QuantiGene Plex assay, western blot, immunofluorescence, and calcium imaging. Our findings showed that UDCA counteracted the effects of CoCl 2 on cell viability, beating frequency, HIF-1α, and p53 protein expression. We found that these cardioprotection effects of UDCA were similar to FTY720, S1P agonist. Furthermore, we observed that UDCA protects CMs against CoCl 2 -induced [Ca 2+ ] i dynamic alteration. Pharmacological inhibition of the Gα i -sensitive receptor did not abolish the cardioprotection of UDCA against CoCl 2 detrimental effects, except for cell viability and [Ca 2+ ] i . Pertussis toxin is partially effective in inhibiting UDCA protection against CoCl 2 effects on CM cell viability. Interestingly, PTX fully inhibits UDCA cardioprotection on CoCl 2 -induced [Ca 2+ ] i dynamic changes. We conclude that UDCA cardioprotection against CoCl 2 -induced hypoxia is similar to FTY720, and its actions are not fully mediated by the Gα i -coupled protein sensitive pathways. Ursodeoxycholic acid is the most hydrophilic bile

  2. Hypoxia-inducible factor-1α plays roles in Epstein-Barr virus's natural life cycle and tumorigenesis by inducing lytic infection through direct binding to the immediate-early BZLF1 gene promoter.

    Directory of Open Access Journals (Sweden)

    Richard J Kraus

    2017-06-01

    Full Text Available When confronted with poor oxygenation, cells adapt by activating survival signaling pathways, including the oxygen-sensitive transcriptional regulators called hypoxia-inducible factor alphas (HIF-αs. We report here that HIF-1α also regulates the life cycle of Epstein-Barr virus (EBV. Incubation of EBV-positive gastric carcinoma AGS-Akata and SNU-719 and Burkitt lymphoma Sal and KemIII cell lines with a prolyl hydroxylase inhibitor, L-mimosine or deferoxamine, or the NEDDylation inhibitor MLN4924 promoted rapid and sustained accumulation of both HIF-1α and lytic EBV antigens. ShRNA knockdown of HIF-1α significantly reduced deferoxamine-mediated lytic reactivation. HIF-1α directly bound the promoter of the EBV primary latent-lytic switch BZLF1 gene, Zp, activating transcription via a consensus hypoxia-response element (HRE located at nt -83 through -76 relative to the transcription initiation site. HIF-1α did not activate transcription from the other EBV immediate-early gene, BRLF1. Importantly, expression of HIF-1α induced EBV lytic-gene expression in cells harboring wild-type EBV, but not in cells infected with variants containing base-pair substitution mutations within this HRE. Human oral keratinocyte (NOK and gingival epithelial (hGET cells induced to differentiate by incubation with either methyl cellulose or growth in organotypic culture accumulated both HIF-1α and Blimp-1α, another cellular factor implicated in lytic reactivation. HIF-1α activity also accumulated along with Blimp-1α during B-cell differentiation into plasma cells. Furthermore, most BZLF1-expressing cells observed in lymphomas induced by EBV in NSG mice with a humanized immune system were located distal to blood vessels in hypoxic regions of the tumors. Thus, we conclude that HIF-1α plays central roles in both EBV's natural life cycle and EBV-associated tumorigenesis. We propose that drugs that induce HIF-1α protein accumulation are good candidates for

  3. Increased accumulation of hypoxia-inducible factor-1α with reduced transcriptional activity mediates the antitumor effect of triptolide

    Directory of Open Access Journals (Sweden)

    Li Zheng

    2010-10-01

    Full Text Available Abstract Background Hypoxia-inducible factor-1α (HIF-1α, a critical transcription factor to reduced O2 availability, has been demonstrated to be extensively involved in tumor survival, aggressive progression, drug resistance and angiogenesis. Thus it has been considered as a potential anticancer target. Triptolide is the main principle responsible for the biological activities of the Traditional Chinese Medicine tripterygium wilfordii Hook F. Triptolide possesses great chemotherapy potential for cancer with its broad-spectrum anticancer, antiangiogenesis, and drug-resistance circumvention activities. Numerous biological molecules inhibited by triptolide have been viewed as its possible targets. However, the anticancer action mechanisms of triptolide remains to be further investigated. Here we used human ovarian SKOV-3 cancer cells as a model to probe the effect of triptolide on HIF-1α. Results Triptolide was observed to inhibit the proliferation of SKOV-3 cells, and meanwhile, to enhance the accumulation of HIF-1α protein in SKOV-3, A549 and DU145 cells under different conditions. Triptolide did not change the kinetics or nuclear localization of HIF-1α protein or the 26 S proteasome activity in SKOV-3 cells. However, triptolide was found to increase the levels of HIF-1α mRNA. Unexpectedly, the HIF-1α protein induced by triptolide appeared to lose its transcriptional activity, as evidenced by the decreased mRNA levels of its target genes including VEGF, BNIP3 and CAIX. The results were further strengthened by the lowered secretion of VEGF protein, the reduced sprout outgrowth from the rat aorta rings and the inhibitory expression of the hypoxia responsive element-driven luciferase reporter gene. Moreover, the silencing of HIF-1α partially prevented the cytotoxicity and apoptosis triggered by triptolide. Conclusions The potent induction of HIF-1α protein involved in its cytotoxicity, together with the suppression of HIF-1 transcriptional

  4. [Association between pulmonary vascular remodeling and expression of hypoxia-inducible factor-1α, endothelin-1 and inducible nitric oxide synthase in pulmonary vessels in neonatal rats with hypoxic pulmonary hypertension].

    Science.gov (United States)

    Wang, Jian-Rong; Zhou, Ying; Sang, Kui; Li, Ming-Xia

    2013-02-01

    To investigate the association between pulmonary vascular remodeling and expression of hypoxia-inducible factor-1α (HIF-1α), endothelin-1 (ET-1) and inducible nitric oxide synthase (iNOS) in pulmonary vessels in neonatal rats with hypoxic pulmonary hypertension (HPH). A neonatal rat model of HPH was established as an HPH group, and normal neonatal rats were enrolled as a control group. The mean pulmonary arterial pressure (mPAP) was measured. The percentage of medial thickness to outer diameter of the small pulmonary arteries (MT%) and the percentage of medial cross-section area to total cross-section area of the pulmonary small arteries (MA%) were measured as the indicators for pulmonary vascular remodeling. The immunohistochemical reaction intensities for HIF-1α, ET-1 and iNOS and their mRNA expression in lung tissues of neonatal rats were measured. Correlation analysis was performed to determine the relationship between pulmonary vascular remodeling and mRNA expression of HIF-1α, ET-1 and iNOS. The mPAP of the HPH group kept increasing on days 3, 5, 7, 10, 14, and 21 of hypoxia, with a significant difference compared with the control group (P<0.05). The HPH group had significantly higher MT% and MA% than the control group from day 7 of hypoxia (P<0.05). HIF-1α protein expression increased significantly on days 3, 5, 7 and 10 days of hypoxia, and HIF-1α mRNA expression increased significantly on days 3, 5 and 7 days of hypoxia in the HPH group compared with the control group (P<0.05). ET-1 protein expression increased significantly on days 3, 5 and 7 days of hypoxia and ET-1 mRNA expression increased significantly on day 3 of hypoxia in the HPH group compared with the control group (P<0.05). Both iNOS protein and mRNA expression were significantly higher on days 3, 5 and 7 days of hypoxia than the control group (P<0.05). Both MT% and MA% were positively correlated with HIF-1α mRNA expression (r=0.835 and 0.850 respectively; P<0.05). Pulmonary vascular

  5. Hypoxic stress up-regulates the expression of Toll-like receptor 4 in macrophages via hypoxia-inducible factor.

    Science.gov (United States)

    Kim, So Young; Choi, Yong Jun; Joung, Sun Myung; Lee, Byung Ho; Jung, Yi-Sook; Lee, Joo Young

    2010-04-01

    Toll-like receptors (TLRs) are germline-encoded innate immune receptors that recognize invading micro-organisms and induce immune and inflammatory responses. Deregulation of TLRs is known to be closely linked to various immune disorders and inflammatory diseases. Cells at sites of inflammation are exposed to hypoxic stress, which further aggravates inflammatory processes. We have examined if hypoxic stress modulates the TLR activity of macrophages. Hypoxia and CoCl(2) (a hypoxia mimetic) enhanced the expression of TLR4 messenger RNA and protein in macrophages (RAW264.7 cells), whereas the messenger RNA of other TLRs was not increased. To determine the underlying mechanism, we investigated the role of hypoxia-inducible factor 1 (HIF-1) in the regulation of TLR4 expression. Knockdown of HIF-1alpha expression by small interfering RNA inhibited hypoxia-induced and CoCl(2)-induced TLR4 expression in macrophages, while over-expression of HIF-1alpha potentiated TLR4 expression. Chromatin immunoprecipitation assays revealed that HIF-1alpha binds to the TLR4 promoter region under hypoxic conditions. In addition, deletion or mutation of a putative HIF-1-binding motif in the TLR4 promoter greatly attenuated HIF-1alpha-induced TLR4 promoter reporter expression. Up-regulation of TLR4 expression by hypoxic stress enhanced the response of macrophages to lipopolysaccharide, resulting in increased expression of cyclooxygenase-2, interleukin-6, regulated on activation normal T cell expressed and secreted, and interferon-inducible protein-10. These results demonstrate that TLR4 expression in macrophages is up-regulated via HIF-1 in response to hypoxic stress, suggesting that hypoxic stress at sites of inflammation enhances susceptibility to subsequent infection and inflammatory signals by up-regulating TLR4.

  6. Cold shock protein YB-1 is involved in hypoxia-dependent gene transcription

    International Nuclear Information System (INIS)

    Rauen, Thomas; Frye, Bjoern C.; Wang, Jialin; Raffetseder, Ute; Alidousty, Christina; En-Nia, Abdelaziz; Floege, Jürgen; Mertens, Peter R.

    2016-01-01

    Hypoxia-dependent gene regulation is largely orchestrated by hypoxia-inducible factors (HIFs), which associate with defined nucleotide sequences of hypoxia-responsive elements (HREs). Comparison of the regulatory HRE within the 3′ enhancer of the human erythropoietin (EPO) gene with known binding motifs for cold shock protein Y-box (YB) protein-1 yielded strong similarities within the Y-box element and 3′ adjacent sequences. DNA binding assays confirmed YB-1 binding to both, single- and double-stranded HRE templates. Under hypoxia, we observed nuclear shuttling of YB-1 and co-immunoprecipitation assays demonstrated that YB-1 and HIF-1α physically interact with each other. Cellular YB-1 depletion using siRNA significantly induced hypoxia-dependent EPO production at both, promoter and mRNA level. Vice versa, overexpressed YB-1 significantly reduced EPO-HRE-dependent gene transcription, whereas this effect was minor under normoxia. HIF-1α overexpression induced hypoxia-dependent gene transcription through the same element and accordingly, co-expression with YB-1 reduced HIF-1α-mediated EPO induction under hypoxic conditions. Taken together, we identified YB-1 as a novel binding factor for HREs that participates in fine-tuning of the hypoxia transcriptome. - Highlights: • Hypoxia drives nuclear translocation of cold shock protein YB-1. • YB-1 physically interacts with hypoxia-inducible factor (HIF)-1α. • YB-1 binds to the hypoxia-responsive element (HRE) within the erythropoietin (EPO) 3′ enhancer. • YB-1 trans-regulates transcription of hypoxia-dependent genes such as EPO and VEGF.

  7. Loss of PINK1 attenuates HIF-1α induction by preventing 4E-BP1-dependent switch in protein translation under hypoxia.

    Science.gov (United States)

    Lin, William; Wadlington, Natasha L; Chen, Linan; Zhuang, Xiaoxi; Brorson, James R; Kang, Un Jung

    2014-02-19

    Parkinson's disease (PD) has multiple proposed etiologies with implication of abnormalities in cellular homeostasis ranging from proteostasis to mitochondrial dynamics to energy metabolism. PINK1 mutations are associated with familial PD and here we discover a novel PINK1 mechanism in cellular stress response. Using hypoxia as a physiological trigger of oxidative stress and disruption in energy metabolism, we demonstrate that PINK1(-/-) mouse cells exhibited significantly reduced induction of HIF-1α protein, HIF-1α transcriptional activity, and hypoxia-responsive gene upregulation. Loss of PINK1 impairs both hypoxia-induced 4E-BP1 dephosphorylation and increase in the ratio of internal ribosomal entry site (IRES)-dependent to cap-dependent translation. These data suggest that PINK1 mediates adaptive responses by activating IRES-dependent translation, and the impairments in translation and the HIF-1α pathway may contribute to PINK1-associated PD pathogenesis that manifests under cellular stress.

  8. Pathophysiological response to hypoxia - from the molecular mechanisms of malady to drug discovery: epigenetic regulation of the hypoxic response via hypoxia-inducible factor and histone modifying enzymes.

    Science.gov (United States)

    Mimura, Imari; Tanaka, Tetsuhiro; Wada, Youichiro; Kodama, Tatsuhiko; Nangaku, Masaomi

    2011-01-01

    The hypoxia response regulated primarily by hypoxia-inducible factor (HIF) influences metabolism, cell survival, and angiogenesis to maintain biological homeostasis. In addition to the traditional transcriptional regulation by HIF, recent studies have shown that epigenetic modulation such as histone methylation, acetylation, and DNA methylation could change the regulation of the response to hypoxia. Eukaryotic chromatin is known to be modified by multiple post-translational histone methylation and demethylation, which result in the chromatin conformation change to adapt to hypoxic stimuli. Interestingly, some of the histone demethylase enzymes, which have the Jumonji domain-containing family, require oxygen to function and are induced by hypoxia in an HIF-1-dependent manner. Recent studies have demonstrated that histone modifiers play important roles in the hypoxic environment such as that in cancer cells and that they may become new therapeutic targets for cancer patients. It may lead to finding a new therapy for cancer to clarify a new epigenetic mechanism by HIF and histone demethylase such as JMJD1A (KDM3A) under hypoxia.

  9. Effect of hypoxia on tissue factor pathway inhibitor expression in breast cancer.

    Science.gov (United States)

    Cui, X Y; Tinholt, M; Stavik, B; Dahm, A E A; Kanse, S; Jin, Y; Seidl, S; Sahlberg, K K; Iversen, N; Skretting, G; Sandset, P M

    2016-02-01

    ESSENTIALS: A hypoxic microenvironment is a common feature of tumors that may influence activation of coagulation. MCF-7 and SK-BR-3 breast cancer cells and breast cancer tissue samples were used. The results showed transcriptional repression of tissue factor pathway inhibitor expression in hypoxia. Hypoxia-inducible factor 1α may be a target for the therapy of cancer-related coagulation and thrombosis. Activation of coagulation is a common finding in patients with cancer, and is associated with an increased risk of venous thrombosis. As a hypoxic microenvironment is a common feature of solid tumors, we investigated the role of hypoxia in the regulation of tissue factor (TF) pathway inhibitor (TFPI) expression in breast cancer. To explore the transcriptional regulation of TFPI by hypoxia-inducible factor (HIF)-1α in breast cancer cells and their correlation in breast cancer tissues. MCF-7 and SK-BR-3 breast cancer cells were cultured in 1% oxygen or treated with cobalt chloride (CoCl2 ) to mimic hypoxia. Time-dependent and dose-dependent downregulation of TFPI mRNA (quantitative RT-PCR) and of free TFPI protein (ELISA) were observed in hypoxia. Western blotting showed parallel increases in the levels of HIF-1α protein and TF. HIF-1α inhibitor abolished or attenuated the hypoxia-induced downregulation of TFPI. Luciferase reporter assay showed that both hypoxia and HIF-1α overexpression caused strong repression of TFPI promoter activity. Subsequent chromatin immunoprecipitation and mutagenesis analysis demonstrated a functional hypoxia response element within the TFPI promoter, located at -1065 to -1060 relative to the transcriptional start point. In breast cancer tissue samples, gene expression analyses showed a positive correlation between the mRNA expression of TFPI and that of HIF-1α. This study demonstrates that HIF-1α is involved in the transcriptional regulation of the TFPI gene, and suggests that a hypoxic microenvironment inside a breast tumor may

  10. Hypoxia-Induced Cisplatin Resistance in Non-Small Cell Lung Cancer Cells Is Mediated by HIF-1α and Mutant p53 and Can Be Overcome by Induction of Oxidative Stress.

    Science.gov (United States)

    Deben, Christophe; Deschoolmeester, Vanessa; De Waele, Jorrit; Jacobs, Julie; Van den Bossche, Jolien; Wouters, An; Peeters, Marc; Rolfo, Christian; Smits, Evelien; Lardon, Filip; Pauwels, Patrick

    2018-04-21

    The compound APR-246 (PRIMA-1 MET ) is a known reactivator of (mutant) p53 and inducer of oxidative stress which can sensitize cancer cells to platinum-based chemotherapeutics. However, the effect of a hypoxic tumor environment has been largely overlooked in this interaction. This study focusses on the role of hypoxia-inducible factor-1α (HIF-1α) and the p53 tumor suppressor protein in hypoxia-induced cisplatin resistance in non-small cell lung cancer (NSCLC) cells and the potential of APR-246 to overcome this resistance. We observed that hypoxia-induced cisplatin resistance only occurred in the p53 mutant NCI-H2228 Q331 * cell line, and not in the wild type A549 and mutant NCI-H1975 R273H cell lines. Cisplatin reduced HIF-1α protein levels in NCI-H2228 Q331 * cells, leading to a shift in expression from HIF-1α-dependent to p53-dependent transcription targets under hypoxia. APR-246 was able to overcome hypoxia-induced cisplatin resistance in NCI-H2228 Q331 * cells in a synergistic manner without affecting mutant p53 Q331 * transcriptional activity, but significantly depleting total glutathione levels more efficiently under hypoxic conditions. Synergism was dependent on the presence of mutant p53 Q331 * and the induction of reactive oxygen species, with depletion of one or the other leading to loss of synergism. Our data further support the rationale of combining APR-246 with cisplatin in NSCLC, since their synergistic interaction is retained or enforced under hypoxic conditions in the presence of mutant p53.

  11. Hypoxia-Induced Cisplatin Resistance in Non-Small Cell Lung Cancer Cells Is Mediated by HIF-1α and Mutant p53 and Can Be Overcome by Induction of Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Christophe Deben

    2018-04-01

    Full Text Available The compound APR-246 (PRIMA-1MET is a known reactivator of (mutant p53 and inducer of oxidative stress which can sensitize cancer cells to platinum-based chemotherapeutics. However, the effect of a hypoxic tumor environment has been largely overlooked in this interaction. This study focusses on the role of hypoxia-inducible factor-1α (HIF-1α and the p53 tumor suppressor protein in hypoxia-induced cisplatin resistance in non-small cell lung cancer (NSCLC cells and the potential of APR-246 to overcome this resistance. We observed that hypoxia-induced cisplatin resistance only occurred in the p53 mutant NCI-H2228Q331* cell line, and not in the wild type A549 and mutant NCI-H1975R273H cell lines. Cisplatin reduced HIF-1α protein levels in NCI-H2228Q331* cells, leading to a shift in expression from HIF-1α-dependent to p53-dependent transcription targets under hypoxia. APR-246 was able to overcome hypoxia-induced cisplatin resistance in NCI-H2228Q331* cells in a synergistic manner without affecting mutant p53Q331* transcriptional activity, but significantly depleting total glutathione levels more efficiently under hypoxic conditions. Synergism was dependent on the presence of mutant p53Q331* and the induction of reactive oxygen species, with depletion of one or the other leading to loss of synergism. Our data further support the rationale of combining APR-246 with cisplatin in NSCLC, since their synergistic interaction is retained or enforced under hypoxic conditions in the presence of mutant p53.

  12. Andrographolide down-regulates hypoxia-inducible factor-1{alpha} in human non-small cell lung cancer A549 cells

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Hui-Hsuan [School of Medical Laboratory and Biotechnology, Chung Shan Medical University, Taichung, Taiwan (China); Department of Medical Research, Chung Shan Medical University Hospital, Taichung, Taiwan (China); Tsai, Chia-Wen [Department of Nutrition, China Medical University, Taichung, Taiwan (China); Chou, Fen-Pi [Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung, Taiwan (China); Wang, Chau-Jong [Department of Medical Research, Chung Shan Medical University Hospital, Taichung, Taiwan (China); Institute of Biochemistry and Biotechnology, Chung Shan Medical University, Taichung, Taiwan (China); Hsuan, Shu-Wen [Department of Medical Laboratory Science and Biotechnology, College of Medicine and Life Science, Chung Hwa University of Medical Technology, No.89, Wen Hwa 1st St., Rende Shiang, Tainan County 717, Taiwan (China); Wang, Cheng-Kun [E-Chyun Dermatology Clinic, No.70, Sec. 3, Jhonghua E. Rd., East District, Tainan, Taiwan (China); Chen, Jing-Hsien [Department of Medical Laboratory Science and Biotechnology, College of Medicine and Life Science, Chung Hwa University of Medical Technology, No.89, Wen Hwa 1st St., Rende Shiang, Tainan County 717, Taiwan (China)

    2011-02-01

    Andrographolide (Andro), a diterpenoid lactone isolated from a traditional herbal medicine Andrographis paniculata, is known to possess multiple pharmacological activities. In our previous study, Andro had been shown to inhibit non-small cell lung cancer (NSCLC) A549 cell migration and invasion via down-regulation of phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. Here we demonstrated that Andro inhibited the expression of hypoxia-inducible factor-1{alpha} (HIF-1{alpha}) in A549 cells. HIF-1{alpha} plays an important role in tumor growth, angiogenesis and lymph node metastasis of NSCLC. The Andro-induced decrease of cellular protein level of HIF-1{alpha} was correlated with a rapid ubiquitin-dependent degradation of HIF-1{alpha}, and was accompanied by increased expressions of hydroxyl-HIF-1{alpha} and prolyl hydroxylase (PHD2), and a later decrease of vascular endothelial growth factor (VEGF) upon the treatment of Andro. The Andro-inhibited VEGF expression appeared to be a consequence of HIF-1{alpha} inactivation, because its DNA binding activity was suppressed by Andro. Molecular data showed that all these effects of Andro might be mediated via TGF{beta}1/PHD2/HIF-1{alpha} pathway, as demonstrated by the transfection of TGF{beta}1 overexpression vector and PHD2 siRNA, and the usage of a pharmacological MG132 inhibitor. Furthermore, we elucidated the involvement of Andro in HIF-1{alpha} transduced VEGF expression in A549 cells and other NSCLC cell lines. In conclusion, these results highlighted the potential effects of Andro, which may be developed as a chemotherapeutic or an anti-angiogenesis agent for NSCLC in the future.

  13. Andrographolide down-regulates hypoxia-inducible factor-1α in human non-small cell lung cancer A549 cells

    International Nuclear Information System (INIS)

    Lin, Hui-Hsuan; Tsai, Chia-Wen; Chou, Fen-Pi; Wang, Chau-Jong; Hsuan, Shu-Wen; Wang, Cheng-Kun; Chen, Jing-Hsien

    2011-01-01

    Andrographolide (Andro), a diterpenoid lactone isolated from a traditional herbal medicine Andrographis paniculata, is known to possess multiple pharmacological activities. In our previous study, Andro had been shown to inhibit non-small cell lung cancer (NSCLC) A549 cell migration and invasion via down-regulation of phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. Here we demonstrated that Andro inhibited the expression of hypoxia-inducible factor-1α (HIF-1α) in A549 cells. HIF-1α plays an important role in tumor growth, angiogenesis and lymph node metastasis of NSCLC. The Andro-induced decrease of cellular protein level of HIF-1α was correlated with a rapid ubiquitin-dependent degradation of HIF-1α, and was accompanied by increased expressions of hydroxyl-HIF-1α and prolyl hydroxylase (PHD2), and a later decrease of vascular endothelial growth factor (VEGF) upon the treatment of Andro. The Andro-inhibited VEGF expression appeared to be a consequence of HIF-1α inactivation, because its DNA binding activity was suppressed by Andro. Molecular data showed that all these effects of Andro might be mediated via TGFβ1/PHD2/HIF-1α pathway, as demonstrated by the transfection of TGFβ1 overexpression vector and PHD2 siRNA, and the usage of a pharmacological MG132 inhibitor. Furthermore, we elucidated the involvement of Andro in HIF-1α transduced VEGF expression in A549 cells and other NSCLC cell lines. In conclusion, these results highlighted the potential effects of Andro, which may be developed as a chemotherapeutic or an anti-angiogenesis agent for NSCLC in the future.

  14. Sestrin2 induced by hypoxia inducible factor1 alpha protects the blood-brain barrier via inhibiting VEGF after severe hypoxic-ischemic injury in neonatal rats.

    Science.gov (United States)

    Shi, Xudan; Doycheva, Desislava Met; Xu, Liang; Tang, Jiping; Yan, Min; Zhang, John H

    2016-11-01

    Hypoxic ischemic (HI) encephalopathy remains the leading cause of perinatal brain injury resulting in long term disabilities. Stabilization of blood brain barrier (BBB) after HI is an important target, therefore, in this study we aim to determine the role of sestrin2, a stress inducible protein which is elevated after various insults, on BBB stabilization after moderate and severe HI injuries. Rat pups underwent common carotid artery ligation followed by either 150min (severe model) or 100min (moderate model) of hypoxia. 1h post HI, rats were intranasally administered with recombinant human sestrin2 (rh-sestrin2) and sacrificed for infarct area, brain water content, righting reflex and geotaxis reflex. Sestrin2 was silenced using siRNA and an activator/inhibitor of hypoxia inducible factor1α (HIF1α) was used to examine their roles on BBB permeability. Rats subjected to severe HI exhibited larger infarct area and higher sestrin2 expression compared to rats in the moderate HI group. rh-sestrin2 attenuated brain infarct and edema, while silencing sestrin2 reversed these protective effects after severe HI. HIF1α induced sestrin2 activation in severe HI but not in moderate HI groups. A HIF1a agonist was shown to increase permeability of the BBB via vascular endothelial growth factor (VEGF) after moderate HI. However, after severe HI, HIF1α activated both VEGF and sestrin2. But HIF1α dependent sestrin2 activation was the predominant pathway after severe HI which inhibited VEGF and attenuated BBB permeability. rh-sestrin2 attenuated BBB permeability via upregulation of endogenous sestrin2 which was induced by HIF1α after severe HI. However, HIF1α's effects as a prodeath or prosurvival signal were influenced by the severity of HI injury. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Inhibition of Vascular Endothelial Growth Factor A and Hypoxia-Inducible Factor 1α Maximizes the Effects of Radiation in Sarcoma Mouse Models Through Destruction of Tumor Vasculature

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hae-June [Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Yoon, Changhwan [Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Park, Do Joong [Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Department of Surgery, Seoul National University Bundang Hospital, Sungnam (Korea, Republic of); Kim, Yeo-Jung [Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Schmidt, Benjamin [Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Lee, Yoon-Jin [Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Tap, William D. [Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Eisinger-Mathason, T.S. Karin [Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Choy, Edwin [Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts (United States); Kirsch, David G. [Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Simon, M. Celeste [Abramson Family Cancer Research Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania (United States); Howard Hughes Medical Institute (United States); and others

    2015-03-01

    Purpose: To examine the addition of genetic or pharmacologic inhibition of hypoxia-inducible factor 1α (HIF-1α) to radiation therapy (RT) and vascular endothelial growth factor A (VEGF-A) inhibition (ie trimodality therapy) for soft-tissue sarcoma. Methods and Materials: Hypoxia-inducible factor 1α was inhibited using short hairpin RNA or low metronomic doses of doxorubicin, which blocks HIF-1α binding to DNA. Trimodality therapy was examined in a mouse xenograft model and a genetically engineered mouse model of sarcoma, as well as in vitro in tumor endothelial cells (ECs) and 4 sarcoma cell lines. Results: In both mouse models, any monotherapy or bimodality therapy resulted in tumor growth beyond 250 mm{sup 3} within the 12-day treatment period, but trimodality therapy with RT, VEGF-A inhibition, and HIF-1α inhibition kept tumors at <250 mm{sup 3} for up to 30 days. Trimodality therapy on tumors reduced HIF-1α activity as measured by expression of nuclear HIF-1α by 87% to 95% compared with RT alone, and cytoplasmic carbonic anhydrase 9 by 79% to 82%. Trimodality therapy also increased EC-specific apoptosis 2- to 4-fold more than RT alone and reduced microvessel density by 75% to 82%. When tumor ECs were treated in vitro with trimodality therapy under hypoxia, there were significant decreases in proliferation and colony formation and increases in DNA damage (as measured by Comet assay and γH2AX expression) and apoptosis (as measured by cleaved caspase 3 expression). Trimodality therapy had much less pronounced effects when 4 sarcoma cell lines were examined in these same assays. Conclusions: Inhibition of HIF-1α is highly effective when combined with RT and VEGF-A inhibition in blocking sarcoma growth by maximizing DNA damage and apoptosis in tumor ECs, leading to loss of tumor vasculature.

  16. Inositol Polyphosphate Multikinase Inhibits Angiogenesis via Inositol Pentakisphosphate-Induced HIF-1α Degradation.

    Science.gov (United States)

    Fu, Chenglai; Tyagi, Richa; Chin, Alfred C; Rojas, Tomas; Li, Ruo-Jing; Guha, Prasun; Bernstein, Isaac A; Rao, Feng; Xu, Risheng; Cha, Jiyoung Y; Xu, Jing; Snowman, Adele M; Semenza, Gregg L; Snyder, Solomon H

    2018-02-02

    Inositol polyphosphate multikinase (IPMK) and its major product inositol pentakisphosphate (IP5) regulate a variety of cellular functions, but their role in vascular biology remains unexplored. We have investigated the role of IPMK in regulating angiogenesis. Deletion of IPMK in fibroblasts induces angiogenesis in both in vitro and in vivo models. IPMK deletion elicits a substantial increase of VEGF (vascular endothelial growth factor), which mediates the regulation of angiogenesis by IPMK. The regulation of VEGF by IPMK requires its catalytic activity. IPMK is predominantly nuclear and regulates gene transcription. However, IPMK does not apparently serve as a transcription factor for VEGF. HIF (hypoxia-inducible factor)-1α is a major determinant of angiogenesis and induces VEGF transcription. IPMK deletion elicits a major enrichment of HIF-1α protein and thus VEGF. HIF-1α is constitutively ubiquitinated by pVHL (von Hippel-Lindau protein) followed by proteasomal degradation under normal conditions. However, HIF-1α is not recognized and ubiquitinated by pVHL in IPMK KO (knockout) cells. IP5 reinstates the interaction of HIF-1α and pVHL. HIF-1α prolyl hydroxylation, which is prerequisite for pVHL recognition, is interrupted in IPMK-deleted cells. IP5 promotes HIF-1α prolyl hydroxylation and thus pVHL-dependent degradation of HIF-1α. Deletion of IPMK in mouse brain increases HIF-1α/VEGF levels and vascularization. The increased VEGF in IPMK KO disrupts blood-brain barrier and enhances brain blood vessel permeability. IPMK, via its product IP5, negatively regulates angiogenesis by inhibiting VEGF expression. IP5 acts by enhancing HIF-1α hydroxylation and thus pVHL-dependent degradation of HIF-1α. © 2017 American Heart Association, Inc.

  17. Urothelial carcinoma associated 1 is a hypoxia-inducible factor-1α-targeted long noncoding RNA that enhances hypoxic bladder cancer cell proliferation, migration, and invasion.

    Science.gov (United States)

    Xue, Mei; Li, Xu; Li, Zhengkun; Chen, Wei

    2014-07-01

    Urothelial carcinoma associated 1 (UCA1) has been identified as an oncogenic long noncoding RNA (lncRNA) that is involved in bladder cancer progression and acts as a diagnostic biomarker for bladder carcinoma. Here, we studied the expression and function of lncRNA-UCA1 in the hypoxic microenvironment of bladder cancer. The expression and transcriptional activity of lncRNA-UCA1 were measured by quantitative real-time polymerase chain reaction and luciferase assays. Cell proliferation and apoptosis were evaluated by MTT assays and flow cytometry. Cell migration and invasion were detected by wound healing, migration, and invasion assays. The binding of hypoxia-inducible factor-1α (HIF-1α) to hypoxia response elements (HREs) in the lncRNA-UCA1 promoter was confirmed by electrophoretic mobility shift assay and chromatin immunoprecipitation. HRE mutations were generated by using a site-directed mutagenesis kit, and HIF-1α knockdown was mediated by small interfering RNA. The effect of HIF-1α inhibition by YC-1 on lncRNA-UCA1 expression was also examined. LncRNA-UCA1 was upregulated by hypoxia in bladder cancer cells. Under hypoxic conditions, lncRNA-UCA1 upregulation increased cell proliferation, migration, and invasion and inhibited apoptosis. The underlying mechanism of hypoxia-upregulated lncRNA-UCA1 expression was that HIF-1α specifically bound to HREs in the lncRNA-UCA1 promoter. Furthermore, HIF-1α knockdown or inhibition could prevent lncRNA-UCA1 upregulation under hypoxia. These findings revealed the mechanism of lncRNA-UCA1 upregulation in hypoxic bladder cancer cells and suggested that effective blocking of lncRNA-UCA1 expression in the hypoxic microenvironment of bladder cancer could be a novel therapeutic strategy.

  18. CypA, a gene downstream of HIF-1α, promotes the development of PDAC.

    Directory of Open Access Journals (Sweden)

    Huan Zhang

    Full Text Available Hypoxia-inducible factor-1α (HIF-1α is a highly important transcription factor involved in cell metabolism. HIF-1α promotes glycolysis and inhibits of mitochondrial respiration in pancreatic ductal adenocarcinoma (PDAC. In response to tumor hypoxia, cyclophilin A (CypA is over-expressed in various cancer types, and is associated with cell apoptosis, tumor invasion, metastasis, and chemoresistance in PDAC. In this study, we showed that both HIF-1α and CypA expression were significantly associated with lymph node metastasis and tumor stage. The expression of CypA was correlated with HIF-1α. Moreover, the mRNA and protein expression of CypA markedly decreased or increased following the suppression or over-expression of HIF-1α in vitro. Chromatin immunoprecipitation analysis showed that HIF-1α could directly bind to the hypoxia response element (HRE in the CypA promoter regions and regulated CypA expression. Consistent with other studies, HIF-1α and CypA promoted PDAC cell proliferation and invasion, and suppressed apoptosis in vitro. Furthermore, we proved the combination effect of 2-methoxyestradiol and cyclosporin A both in vitro and in vivo. These results suggested that,CypA, a gene downstream of HIF-1α, could promote the development of PDAC. Thus, CypA might serve as a potential therapeutic target for PDAC.

  19. Role of hypoxia-inducible factor-α in hepatitis-B-virus X protein-mediated MDR1 activation

    International Nuclear Information System (INIS)

    Han, Hyo-Kyung; Han, Chang Yeob; Cheon, Eun-Pa; Lee, Jaewon; Kang, Keon Wook

    2007-01-01

    The transition from chemotherapy-responsive cancer cells to chemotherapy-resistant cancer cells is mainly accompanied by the increased expression of multi-drug resistance 1 (MDR1). We found that hepatitis-B-virus X protein (HBx) increases the transcriptional activity and protein level of MDR1 in a hepatoma cell line, H4IIE. In addition, HBx overexpression made H4IIE cells more resistant to verapamil-uptake. HBx stabilized hypoxia-inducible factor-1α (HIF-1α) and induced the nuclear translocation of C/EBPβ. Reporter gene analyses showed that HBx increased the reporter activity in the cells transfected with the reporter containing MDR1 gene promoter. Moreover, the luciferase reporter gene activity was significantly inhibited by HIF-1α siRNA but not by overexpression of C/EBP dominant negative mutant. These results imply that HBx increases the MDR1 transporter activity through the transcriptional activation of the MDR1 gene with HIF-1α activation, and suggest HIF-1α for the therapeutic target of HBV-mediated chemoresistance

  20. SN-38 Acts as a Radiosensitizer for Colorectal Cancer by Inhibiting the Radiation-induced Up-regulation of HIF-1α.

    Science.gov (United States)

    Okuno, Takayuki; Kawai, Kazushige; Hata, Keisuke; Murono, Koji; Emoto, Shigenobu; Kaneko, Manabu; Sasaki, Kazuhito; Nishikawa, Takeshi; Tanaka, Toshiaki; Nozawa, Hiroaki

    2018-06-01

    Hypoxia offers resistance to therapy in human solid tumors. The aim of the study was to investigate whether SN-38, the active metabolite of irinotecan, acts as a radiosensitizer through inhibition of hypoxia-inducible factor (HIF)-1α in the human colorectal cancer (CRC) cells. HT29 and SW480 cells were cultured with SN-38 (0-4 μM) immediately after irradiation (0-8 Gy). HIF-1α expression was assessed using flow-cytometry and western blot analysis. Cell proliferation was evaluated by the calcein assay. Apoptosis and cell cycle were determined by flow-cytometry. Radiation up-regulated HIF-1α, and SN-38 inhibited the radiation-induced HIF-1α. The combination of radiation and SN-38 inhibited cell proliferation more than radiation alone; treatment with SN-38 after radiation exposure did not increase the number of apoptotic cells, whereas, it enhanced the S and G 2 /M cell-cycle arrest and decreased the population of cells in G 1 Conclusion: SN-38 inhibits the radiation-induced up-regulation of HIF-1α and acts as a radiosensitizer by inducing cell-cycle arrest in CRC cells. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  1. Role of HIF-1α signaling pathway in osteoarthritis: a systematic review

    Directory of Open Access Journals (Sweden)

    Javier Fernández-Torres

    Full Text Available Abstract Osteoarthritis (OA is the most common form of arthritis and is frequently diagnosed and managed in primary care; it is characterized by loss of articular hyaline cartilage, which is a unique connective tissue that physiologically lacks blood vessels. Articular cartilage survives in a microenvironment devoid of oxygen, which is regulated by hypoxia inducible factor (HIF-1α. HIF-1α is considered the main transcriptional regulator of cellular and developmental response to hypoxia. To date, the relevance of HIF-1α in the assessment of cartilage has increased since its participation is essential in the homeostasis of this tissue. Taking into account the new emerging insights of HIF-1α in the scientific literature in the last years, we focused the present review on the potential role of HIF-1α signaling pathway in OA development, especially in how some genetic factors may influence the maintenance or breakdown of articular cartilage.

  2. HIF-1α Promotes Epithelial-Mesenchymal Transition and Metastasis through Direct Regulation of ZEB1 in Colorectal Cancer.

    Directory of Open Access Journals (Sweden)

    Wenjing Zhang

    Full Text Available It is well recognized that hypoxia-inducible factor 1 alpha (HIF-1α is involved in cancer metastasis, chemotherapy and poor prognosis. We previously found that deferoxamine, a hypoxia-mimetic agent, induces epithelial-mesenchymal transition (EMT in colorectal cancer. Therefore, here we explored a new molecular mechanism for HIF-1α contributing to EMT and cancer metastasis through binding to ZEB1. In this study, we showed that overexpression of HIF-1α with adenovirus infection promoted EMT, cell invasion and migration in vitro and in vivo. On a molecular level, HIF-1α directly binding to the proximal promoter of ZEB1 via hypoxia response element (HRE sites thus increasing the transactivity and expression of ZEB1. In addition, inhibition of ZEB1 was able to abrogate the HIF-1α-induced EMT and cell invasion. HIF-1α expression was highly correlated with the expression of ZEB1 in normal colorectal epithelium, primary and metastatic CRC tissues. Interestingly, both HIF-1α and ZEB1 were positively associated with Vimentin, an important mesenchymal marker of EMT, whereas negatively associated with E-cadherin expression. These findings suggest that HIF-1α enhances EMT and cancer metastasis by binding to ZEB1 promoter in CRC. HIF-1α and ZEB1 are both widely considered as tumor-initiating factors, but our results demonstrate that ZEB1 is a direct downstream of HIF-1α, suggesting a novel molecular mechanism for HIF-1α-inducing EMT and cancer metastasis.

  3. Hypoxia-Inducible Factor-1α: A Potential Factor for the Enhancement of Osseointegration between Dental Implants and Tissue-Engineered Bone

    Directory of Open Access Journals (Sweden)

    Duohong Zou

    2011-07-01

    Full Text Available Introduction: Tissue-engineered bones are widely utilized to protect healthy tissue, reduce pain, and increase the success rate of dental implants. one of the most challenging obstacles lies in obtaining effective os-seointegration between dental implants and tissue-engineered structures. Deficiencies in vascularization, osteogenic factors, oxygen, and other nutrients inside the tissue-engineered bone during the early stages following implantation all inhibit effective osseointe-gration. Oxygen is required for aerobic metabolism in bone and blood vessel tissues, but oxygen levels inside tissue-engineered bone are not suf-ficient for cell proliferation. HIF-1α is a pivotal regulator of hypoxic and ischemic vascular responses, driving transcriptional activation of hundreds of genes involved in vascular reactivity, angiogenesis, arteriogenesis, and osteogenesis.The hypothesis: Hypoxia-Inducible Factor-1α seems a potential factor for the enhancement of osseointegration between dental implants and tissue-engineered bone.Evaluation of the hypothesis: Enhancement of HIF-1α protein expression is recognized as the most promising approach for angiogenesis, because it can induce multiple angiogenic targets in a coordinated manner. Therefore, it will be a novel potential therapeutic methods targeting HIF-1α expression to enhance osseointegration be-tween dental implants and tissue-engineered bone.

  4. Essential role for SphK1/S1P signaling to regulate hypoxia-inducible factor 2α expression and activity in cancer.

    Science.gov (United States)

    Bouquerel, P; Gstalder, C; Müller, D; Laurent, J; Brizuela, L; Sabbadini, R A; Malavaud, B; Pyronnet, S; Martineau, Y; Ader, I; Cuvillier, O

    2016-03-14

    The sphingosine kinase-1/sphingosine 1-phosphate (SphK1/S1P) signaling pathway has been reported to modulate the expression of the canonical transcription factor hypoxia-inducible HIF-1α in multiple cell lineages. HIF-2α is also frequently overexpressed in solid tumors but its role has been mostly studied in clear cell renal cell carcinoma (ccRCC), the most common form of kidney cancer, where HIF-2α has been established as a driver of a more aggressive disease. In this study, the role of SphK1/S1P signaling with regard to HIF-2α was investigated in various cancer cell models including ccRCC cells. Under hypoxic conditions or in ccRCC lacking a functional von Hippel-Lindau (VHL) gene and expressing high levels of HIF-2α, SphK1 activity controls HIF-2α expression and transcriptional activity through a phospholipase D (PLD)-driven mechanism. SphK1 silencing promotes a VHL-independent HIF-2α loss of expression and activity and reduces cell proliferation in ccRCC. Importantly, downregulation of SphK1 is associated with impaired Akt and mTOR signaling in ccRCC. Taking advantage of a monoclonal antibody neutralizing extracellular S1P, we show that inhibition of S1P extracellular signaling blocks HIF-2α accumulation in ccRCC cell lines, an effect mimicked when the S1P transporter Spns2 or the S1P receptor 1 (S1P1) is silenced. Here, we report the first evidence that the SphK1/S1P signaling pathway regulates the transcription factor hypoxia-inducible HIF-2α in diverse cancer cell lineages notably ccRCC, where HIF-2α has been established as a driver of a more aggressive disease. These findings demonstrate that SphK1/S1P signaling may act as a canonical regulator of HIF-2α expression in ccRCC, giving support to its inhibition as a therapeutic strategy that could contribute to reduce HIF-2 activity in ccRCC.

  5. l-2-Oxothiazolidine-4-Carboxylic Acid or α-Lipoic Acid Attenuates Airway Remodeling: Involvement of Nuclear Factor-κB (NF-κB, Nuclear Factor Erythroid 2p45-Related Factor-2 (Nrf2, and Hypoxia-Inducible Factor (HIF

    Directory of Open Access Journals (Sweden)

    Heung Bum Lee

    2012-06-01

    Full Text Available Reactive oxygen species (ROS play a crucial role in the pathogenesis of acute and chronic respiratory diseases. Antioxidants have been found to ameliorate airway inflammation and hyperresponsiveness in animal models employing short-term exposure to allergen. However, little data are available on the effect of antioxidants on airway remodeling and signaling pathways in chronic asthma. In the present study, we used a long-term exposure murine model of allergic airway disease to evaluate the effects of an antioxidant, l-2-oxothiazolidine-4-carboxylic acid (OTC or α-lipoic acid (LA on airway remodeling, focusing on the ROS-related hypoxia-inducible signaling. Long-term challenge of ovalbumin (OVA increased ROS production, airway inflammation, and airway hyperresponsiveness, and developed features of airway remodeling such as excessive mucus secretion, subepithelial fibrosis, and thickening of the peribronchial smooth muscle layer. Administration of OTC or LA reduced these features of asthma, including airway remodeling, which was accompanied by suppression of transforming growth factor1, vascular endothelial growth factor, and T-helper 2 cytokines. In addition, OVA-induced activation of nuclear factor-κB (NF-κB, nuclear factor erythroid 2p45-related factor-2 (Nrf2, hypoxia-inducible factor (HIF-1α, and HIF-2α was reduced by OTC or LA. Our results also showed that OTC or LA down-regulated phosphoinositide 3-kinase activity and decreased phosphorylation of p38 mitogen-activated protein kinase but not extracellular signal-regulated kinase 1/2 or c-Jun N-terminal kinase. These findings demonstrate that OTC and LA can inhibit activation of NF-κB, Nrf2, and HIF, leading to attenuate allergen-induced airway remodeling.

  6. The histone deacetylase inhibitor, Vorinostat, represses hypoxia inducible factor 1 alpha expression through translational inhibition.

    Directory of Open Access Journals (Sweden)

    Darren M Hutt

    Full Text Available Hypoxia inducible factor 1α (HIF-1α is a master regulator of tumor angiogenesis being one of the major targets for cancer therapy. Previous studies have shown that Histone Deacetylase Inhibitors (HDACi block tumor angiogenesis through the inhibition of HIF-1α expression. As such, Vorinostat (Suberoylanilide Hydroxamic Acid/SAHA and Romidepsin, two HDACis, were recently approved by the Food and Drug Administration (FDA for the treatment of cutaneous T cell lymphoma. Although HDACis have been shown to affect HIF-1α expression by modulating its interactions with the Hsp70/Hsp90 chaperone axis or its acetylation status, the molecular mechanisms by which HDACis inhibit HIF-1α expression need to be further characterized. Here, we report that the FDA-approved HDACi Vorinostat/SAHA inhibits HIF-1α expression in liver cancer-derived cell lines, by a new mechanism independent of p53, prolyl-hydroxylases, autophagy and proteasome degradation. We found that SAHA or silencing of HDAC9 mechanism of action is due to inhibition of HIF-1α translation, which in turn, is mediated by the eukaryotic translation initiation factor--eIF3G. We also highlighted that HIF-1α translation is dramatically inhibited when SAHA is combined with eIF3H silencing. Taken together, we show that HDAC activity regulates HIF-1α translation, with HDACis such as SAHA representing a potential novel approach for the treatment of hepatocellular carcinoma.

  7. [Genetic cloning and expression of hypoxia inducible factor 1 alpha in high altitude hypoxic adaptation species Tibetan antelope (Pantholops hodgsonii)].

    Science.gov (United States)

    Liu, Fang; Wuren, Tana; Ma, Lan; Yang, Ying-Zhong; Ge, Ri-Li

    2011-12-25

    In order to investigate the role of the hypoxia inducible factor 1 alpha (HIF-1α) in the adaptation mechanism to high altitude hypoxia, the cloning of the HIF-1α gene cDNA of Tibetan antelope (Pantholops hodgsonii), using RT-PCR and RACE, was applied, and the comparative analysis of the tissue-specific expressions of HIF-1α among Tibetan antelope, Tibetan sheep and plain sheep was performed using real-time PCR and Western blot. The sequence analysis indicated that the cDNA sequences acquired by cloning from the HIF-1α gene of Tibetan antelope comprised a 2 471-bp open reading frame (ORF) and a 1 911-bp 3'UTR. The similarity between its coding sequence, predicted amino acid sequence and HIF-1α of other mammals exceeded 87%, in which the similarity with cow was up to more than 98%, which showed that this sequence was the cDNA of HIF-1α of Tibetan antelope. The results of real-time PCR and Western blot showed that expressions of HIF-1α mRNA and protein appeared in Tibetan antelope's lung, cardiac muscle and skeletal muscle, with the highest expression in lung. HIF-1α mRNA and protein had obvious differential expression in these tissues. Further research showed that Tibetan antelope and Tibetan sheep possessed higher expressions of HIF-1α protein in the three tissues above-mentioned compared with plain sheep, and the expressions of HIF-1α mRNA and protein in Tibetan antelope's lung, cardiac muscle and skeletal muscle were higher than those of Tibetan sheep. It illustrates that the hypoxic HIF-1α-specific expression is one of the molecular bases of high altitude hypoxia adaptation in Tibetan antelope.

  8. Multiple roles of hypoxia in ovarian function: roles of hypoxia-inducible factor-related and -unrelated signals during the luteal phase

    OpenAIRE

    Nishimura, Ryo; Okuda, Kiyoshi

    2015-01-01

    There is increasing interest in the role of oxygen conditions in the microenvironment of organs because of the discovery of a hypoxia-specific transcription factor, namely hypoxia-inducible factor (HIF) 1. Ovarian function has several phases that change day by day, including ovulation, follicular growth and corpus luteum formation and regression. These phases are regulated by many factors, including pituitary hormones and local hormones, such as steroids, peptides and cytokines, as well as ox...

  9. Radiosensitization of normoxic and hypoxic h1339 lung tumor cells by heat shock protein 90 inhibition is independent of hypoxia inducible factor-1α.

    Science.gov (United States)

    Schilling, Daniela; Bayer, Christine; Li, Wei; Molls, Michael; Vaupel, Peter; Multhoff, Gabriele

    2012-01-01

    Ionizing irradiation is a commonly accepted treatment modality for lung cancer patients. However, the clinical outcome is hampered by normal tissue toxicity and tumor hypoxia. Since tumors often have higher levels of active heat shock protein 90 (Hsp90) than normal tissues, targeting of Hsp90 might provide a promising strategy to sensitize tumors towards irradiation. Hsp90 client proteins include oncogenic signaling proteins, cell cycle activators, growth factor receptors and hypoxia inducible factor-1α (HIF-1α). Overexpression of HIF-1α is assumed to promote malignant transformation and tumor progression and thus might reduce the accessibility to radiotherapy. Herein, we describe the effects of the novel Hsp90 inhibitor NVP-AUY922 and 17-allylamino-17-demethoxygeldanamycin (17-AAG), as a control, on HIF-1α levels and radiosensitivity of lung carcinoma cells under normoxic and hypoxic conditions. NVP-AUY922 exhibited a similar biological activity to that of 17-AAG, but at only 1/10 of the dose. As expected, both inhibitors reduced basal and hypoxia-induced HIF-1α levels in EPLC-272H lung carcinoma cells. However, despite a down-regulation of HIF-1α upon Hsp90 inhibition, sensitivity towards irradiation remained unaltered in EPLC-272H cells under normoxic and hypoxic conditions. In contrast, treatment of H1339 lung carcinoma cells with NVP-AUY922 and 17-AAG resulted in a significant up-regulation of their initially high HIF-1α levels and a concomitant increase in radiosensitivity. In summary, our data show a HIF-1α-independent radiosensitization of normoxic and hypoxic H1339 lung cancer cells by Hsp90 inhibition.

  10. Effects of YC-1 on hypoxia-inducible factor 1 alpha in hypoxic human bladder transitional carcinoma cell line T24 cells.

    Science.gov (United States)

    Li, Yangle; Zhao, Xiaokun; Tang, Huiting; Zhong, Zhaohui; Zhang, Lei; Xu, Ran; Li, Songchao; Wang, Yi

    2012-01-01

    It was the aim of this study to explore the effects of 3-(5'-hydroxymethyl-2'-furyl)-l-benzyl indazole (YC-1) on transcription activity, cell proliferation and apoptosis of hypoxic human bladder transitional carcinoma cells (BTCC), mediated by hypoxia-inducible factor 1α (HIF-1α). BTCC cell line T24 cells were incubated under normoxic or hypoxic conditions, adding different doses of YC-1. The protein expression of HIF-1α and HIF-1α-mediated genes was detected by Western blotting. RT-PCR was used to detect HIF-1α mRNA expression. Cell proliferation, apoptosis and migration activity were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry and transwell migration assay. The cells were pretreated by two ERK/p38 MAPK pathway-specific inhibitors, PD98059 or SB203580, and then incubated with YC-1 treatment under hypoxic condition. HIF-1α protein expression was detected by Western blotting. Hypoxic T24 cells expressed a higher level of HIF-1α, vascular endothelial growth factor, matrix metalloproteinases-2, B-cell lymphoma/leukemia-2 protein and HIF-1α mRNA compared with normoxic controls, in which the above-mentioned expression was downregulated by YC-1 in a dose-dependent manner. Cell proliferation and migration activity were inhibited while apoptosis was induced by YC-1 under hypoxic condition. Moreover, YC-1-downregulated HIF-1α expression was reversed by PD98059 and SB203580, respectively. YC-1 inhibits HIF-1α and HIF-1α-mediated gene expression, cell proliferation and migration activity and induces apoptosis in hypoxic BTCC. The ERK/p38 MAPK pathway may be involved in YC-1-mediated inhibition of HIF-1α. Copyright © 2011 S. Karger AG, Basel.

  11. Prognostic role of hypoxia-inducible factor-1 alpha expression in osteosarcoma: a meta-analysis

    Directory of Open Access Journals (Sweden)

    Ren HY

    2016-03-01

    Full Text Available Hai-Yong Ren,1 Yin-Hua Zhang,1,2 Heng-Yuan Li,1 Tao Xie,1 Ling-Ling Sun,1 Ting Zhu,1 Sheng-Dong Wang,1 Zhao-Ming Ye1 1Department of Orthopaedics, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, 2The First Department of Orthopaedics, Hospital of Zhejiang General Corps of Armed Police Forces, Jiaxing, People’s Republic of China Background: Hypoxia-inducible factor-1α (HIF-1α plays an important role in tumor progression and metastasis. A number of studies have investigated the association of HIF-1α with prognosis and clinicopathological characteristics of osteosarcoma but yielded inconsistent results.  Method: Systematic computerized searches were performed in PubMed, Embase, and Web of Science databases for relevant original articles. The pooled hazard ratios (HRs and odds ratios (ORs with corresponding confidence intervals (CIs were calculated to assess the prognostic value of HIF-1α expression. The standard mean difference was used to analyze the continuous variable.  Results: Finally, nine studies comprising 486 patients were subjected to final analysis. Protein expression level of HIF-1α was found to be significantly related to overall survival (HR =3.0; 95% CI: 1.46–6.15, disease-free survival (HR =2.23; 95% CI: 1.26–3.92, pathologic grade (OR =21.33; 95% CI: 4.60–98.88, tumor stage (OR =10.29; 95% CI: 3.55–29.82, chemotherapy response (OR =9.68; 95% CI: 1.87–50.18, metastasis (OR =5.06; 95% CI: 2.87–8.92, and microvessel density (standard mean difference =2.83; 95% CI: 2.28–3.39.  Conclusion: This meta-analysis revealed that overexpression of HIF-1α is a predictive factor of poor outcomes for osteosarcoma. HIF-1α appeared to play an important role in prognostic evaluation and may be a potential target in antitumoral therapy. Keywords: HIF-1α, osteosarcoma, prognosis, meta-analysis

  12. Manganese (II) induces chemical hypoxia by inhibiting HIF-prolyl hydroxylase: Implication in manganese-induced pulmonary inflammation

    International Nuclear Information System (INIS)

    Han, Jeongoh; Lee, Jong-Suk; Choi, Daekyu; Lee, Youna; Hong, Sungchae; Choi, Jungyun; Han, Songyi; Ko, Yujin; Kim, Jung-Ae; Mi Kim, Young; Jung, Yunjin

    2009-01-01

    Manganese (II), a transition metal, causes pulmonary inflammation upon environmental or occupational inhalation in excess. We investigated a potential molecular mechanism underlying manganese-induced pulmonary inflammation. Manganese (II) delayed HIF-1α protein disappearance, which occurred by inhibiting HIF-prolyl hydroxylase (HPH), the key enzyme for HIF-1α hydroxylation and subsequent von Hippel-Lindau(VHL)-dependent HIF-1α degradation. HPH inhibition by manganese (II) was neutralized significantly by elevated dose of iron. Consistent with this, the induction of cellular HIF-1α protein by manganese (II) was abolished by pretreatment with iron. Manganese (II) induced the HIF-1 target gene involved in pulmonary inflammation, vascular endothelial growth factor (VEGF), in lung carcinoma cell lines. The induction of VEGF was dependent on HIF-1. Manganese-induced VEGF promoted tube formation of HUVEC. Taken together, these data suggest that HIF-1 may be a potential mediator of manganese-induced pulmonary inflammation

  13. ERRα augments HIF-1 signalling by directly interacting with HIF-1α in normoxic and hypoxic prostate cancer cells.

    Science.gov (United States)

    Zou, Chang; Yu, Shan; Xu, Zhenyu; Wu, Dinglan; Ng, Chi-Fai; Yao, Xiaoqiang; Yew, David T; Vanacker, Jean-Marc; Chan, Franky L

    2014-05-01

    Adaptation of cancer cells to a hypoxic microenvironment is important for their facilitated malignant growth and advanced development. One major mechanism mediating the hypoxic response involves up-regulation of hypoxia-inducible factor 1 (HIF-1) expression, which controls reprogramming of energy metabolism and angiogenesis. Oestrogen-related receptor-α (ERRα) is a pivotal regulator of cellular energy metabolism and many biosynthetic pathways, and has also been proposed to be an important factor promoting the Warburg effect in advanced cancer. We and others have previously shown that ERRα expression is increased in prostate cancer and is also a prognostic marker. Here we show that ERRα is oncogenic in prostate cancer and also a key hypoxic growth regulator. ERRα-over-expressing prostate cancer cells were more resistant to hypoxia and showed enhanced HIF-1α protein expression and HIF-1 signalling. These effects could also be observed in ERRα-over-expressing cells grown under normoxia, suggesting that ERRα could function to pre-adapt cancer cells to meet hypoxia stress. Immunoprecipitation and FRET assays indicated that ERRα could physically interact with HIF-1α via its AF-2 domain. A ubiquitination assay showed that this ERRα-HIF-1α interaction could inhibit ubiquitination of HIF-1α and thus reduce its degradation. Such ERRα-HIF-1α interaction could be attenuated by XCT790, an ERRα-specific inverse agonist, resulting in reduced HIF-1α levels. In summary, we show that ERRα can promote the hypoxic growth adaptation of prostate cancer cells via a protective interaction with HIF-1α, suggesting ERRα as a potential therapeutic target for cancer treatment. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  14. The potential role of Brachyury in inducing epithelial-to-mesenchymal transition (EMT) and HIF-1α expression in breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Chao [Department of Mammary Surgery, Zhongshan Hospital of Sun Yat-sen University, Zhongshan, 528403 (China); Zhang, Jingjing, E-mail: jingjingzhangzs@163.com [Department of Cancer Radiotherapy, Zhongshan Hospital of Sun Yat-sen University, Zhongshan, 528403 (China); Fu, Jianhua [Department of Thoracic Surgery, Cancer Center, Zhongshan Hospital of Sun Yat-sen University, Zhongshan, 528403 (China); Ling, Feihai, E-mail: feihailingfhl@163.com [Department of Mammary Surgery, Zhongshan Hospital of Sun Yat-sen University, Zhongshan, 528403 (China)

    2015-11-27

    One of transcription factors of the T-box family, Brachyury has been implicated in tumorigenesis of many types of cancers, regulating cancer cell proliferation, metastasis, invasion and epithelial-to-mesenchymal transition (EMT). However, the role of Brachyury in breast cancer cells has been scarcely reported. The present study aimed to investigate the expression and role of Brachyury in breast cancer. Brachyury expression was analyzed by qRT-PCR and Western blot. The correlations between Brachyury expression and clinicopathological factors of breast cancer were determined. Involvement of EMT stimulation and hypoxia-inducible factor-1α (HIF-1α) expression induction by Brachyury was also evaluated. Moreover, the effect of Brachyury on tumor growth and metastasis in vivo was examined in a breast tumor xenograft model. Brachyury expression was enhanced in primary breast cancer tissues and Brachyury expression was correlated with tumor stage and lymph node metastasis. Hypoxia enhanced Brachyury expression, the silencing of which blocked the modulation effect of hypoxia on E-cadherin and vimentin expression. Brachyury significantly augmented HIF-1alpha expression via PTEN/Akt signaling as well as accelerated cell proliferation and migration in vitro. Additionally, Brachyury accelerated breast tumor xenograft growth and increased lung metastasis in nude mice. In summary, our data confirmed that Brachyury might contribute to hypoxia-induced EMT of breast cancer and trigger HIF-1alpha expression via PTEN/Akt signaling. - Highlights: • Brachyury expression was correlated with tumor stage and lymph node metastasis. • Hypoxia enhanced Brachyury expression, which contributes to hypoxia-induced EMT. • Brachyury significantly augmented HIF-1alpha expression via PTEN/Akt signaling. • Brachyury accelerated tumor xenograft growth and increased lung metastasis.

  15. [Effects of intermittent hypoxic exposure on the parameter of erythrocyte and serum hypoxia inducible factor-1 alpha and erythropoietin levels].

    Science.gov (United States)

    Zhang, Cheng-yan; Zhang, Ji-xin; Lü, Xiao-tao; Li, Bao-yu

    2009-10-01

    To investigate the effects of intermittent hypoxic exposure and normoxic convalescence on the parameter of erythrocyte and serum hypoxia inducible factor-1 alpha (HIF-1alpha) and erythropoietin (EPO) levels. Rat models of intermittent hypoxic exposure were established, combined with the clinical research on volunteers experiencing the intermittent plateau work. Blood samples for red blood cell (RBC) counts, hemoglobin (Hb) and hematocrit (HCT) were collected, serum HIF-1alpha and EPO levels were measured using enzyme linked immunosorbent assay. RBC counts, Hb concentration and HCT were significantly higher than the normoxic group (P hypoxic exposure can enhance serum hypoxia inducible factor-1 alpha and erythropointin levels and the generation of red blood cells, which leads to an increase in hemoglobin concentration and hematocrit. The results have changed with the hypoxic exposure period prolonged. Normoxic convalescence after intermittent hypoxic exposure can make the related indexes reduced, and contribute to the organism recovery.

  16. HIF-2α Expression Regulates Sprout Formation into 3D Fibrin Matrices in Prolonged Hypoxia in Human Microvascular Endothelial Cells.

    Science.gov (United States)

    Nauta, Tessa D; Duyndam, Monique C A; Weijers, Ester M; van Hinsbergh, Victor M W; Koolwijk, Pieter

    2016-01-01

    During short-term hypoxia, Hypoxia Inducible Factors (particular their subunits HIF-1α and HIF-2α) regulate the expression of many genes including the potent angiogenesis stimulator VEGF. However, in some pathological conditions chronic hypoxia occurs and is accompanied by reduced angiogenesis. We investigated the effect of prolonged hypoxia on the proliferation and sprouting ability of human microvascular endothelial cells and the involvement of the HIFs and Dll4/Notch signaling. Human microvascular endothelial cells (hMVECs), cultured at 20% oxygen for 14 days and seeded on top of 3D fibrin matrices, formed sprouts when stimulated with VEGF-A/TNFα. In contrast, hMVECs precultured at 1% oxygen for 14 days were viable and proliferative, but did not form sprouts into fibrin upon VEGF-A/TNFα stimulation at 1% oxygen. Silencing of HIF-2α with si-RNA partially restored the inhibition of endothelial sprouting, whereas HIF-1α or HIF-3α by si-RNA had no effect. No involvement of Dll4/Notch pathway in the inhibitory effect on endothelial sprouting by prolonged hypoxia was found. In addition, hypoxia decreased the production of urokinase-type plasminogen activator (uPA), needed for migration and invasion, without a significant effect on its inhibitor PAI-1. This was independent of HIF-2α, as si-HIF-2α did not counteract uPA reduction. Prolonged culturing of hMVECs at 1% oxygen inhibited endothelial sprouting into fibrin. Two independent mechanisms contribute. Silencing of HIF-2α with si-RNA partially restored the inhibition of endothelial sprouting pointing to a HIF-2α-dependent mechanism. In addition, reduction of uPA contributed to reduced endothelial tube formation in a fibrin matrix during prolonged hypoxia.

  17. The stabilization of hypoxia inducible factor modulates differentiation status and inhibits the proliferation of mouse embryonic stem cells.

    Science.gov (United States)

    Binó, Lucia; Kučera, Jan; Štefková, Kateřina; Švihálková Šindlerová, Lenka; Lánová, Martina; Kudová, Jana; Kubala, Lukáš; Pacherník, Jiří

    2016-01-25

    Hypoxic conditions are suggested to affect the differentiation status of stem cells (SC), including embryonic stem cells (ESC). Hypoxia inducible factor (HIF) is one of the main intracellular molecules responsible for the cellular response to hypoxia. Hypoxia stabilizes HIF by inhibiting the activity of HIF prolyl-hydroxylases (PHD), which are responsible for targeting HIF-alpha subunits for proteosomal degradation. To address the impact of HIF stabilization on the maintenance of the stemness signature of mouse ESC (mESC), we tested the influence of the inhibition of PHDs and hypoxia (1% O2 and 5% O2) on spontaneous ESC differentiation triggered by leukemia inhibitory factor withdrawal for 24 and 48 h. The widely used panhydroxylase inhibitor dimethyloxaloylglycine (DMOG) and PHD inhibitor JNJ-42041935 (JNJ) with suggested higher specificity towards PHDs were employed. Both inhibitors and both levels of hypoxia significantly increased HIF-1alpha and HIF-2alpha protein levels and HIF transcriptional activity in spontaneously differentiating mESC. This was accompanied by significant downregulation of cell proliferation manifested by the complete inhibition of DNA synthesis and partial arrest in the S phase after 48 h. Further, HIF stabilization enhanced downregulation of the expressions of some pluripotency markers (OCT-4, NANOG, ZFP-42, TNAP) in spontaneously differentiating mESC. However, at the same time, there was also a significant decrease in the expression of some genes selected as markers of cell differentiation (e.g. SOX1, BRACH T, ELF5). In conclusion, the short term stabilization of HIF mediated by the PHD inhibitors JNJ and DMOG and hypoxia did not prevent the spontaneous loss of pluripotency markers in mESC. However, it significantly downregulated the proliferation of these cells. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  18. Baltic salmon (Salmo salar) yolk-sac fry mortality is associated with disturbances in the function of hypoxia-inducible transcription factor (HIF-1α) and consecutive gene expression

    International Nuclear Information System (INIS)

    Vuori, Kristiina A.M.; Soitamo, Arto; Vuorinen, Pekka J.; Nikinmaa, Mikko

    2004-01-01

    Baltic salmon (Salmo salar) suffer from abnormally high yolk-sac fry mortality designated as M74-syndrome. In 1990s, 25-80% of salmon females, which ascended rivers to spawn, produced yolk-sac fry suffering from the syndrome. Symptoms of M74-affected fry include neurological disturbances, impaired vascular development and abnormal haemorrhages. The latter symptoms are observed in mammalian embryos if the function of hypoxia inducible transcription factor (HIF-1α), its dimerization partner aryl hydrocarbon nuclear translocator (ARNT) or target gene vascular endothelial growth factor (VEGF) is disturbed. To study the possible involvement of HIF-1α and its target gene VEGF in the development of the syndrome, we collected healthy and M74-affected wild Baltic salmon yolk-sac fry and analyzed HIF-1α mRNA and protein expression, HIF-1α DNA-binding, target gene VEGF protein expression, and blood vessel density in both groups at different stages of yolk-sac fry development. In addition, since Baltic salmon females contain organochlorine contaminants, which have been suggested to be the cause of M74 syndrome via the aryl hydrocarbon receptor (AhR)-dependent gene expression pathway, we studied AhR protein expression, AhR DNA-binding and target gene CYP1A protein expression. Since the parents of both healthy and M74-affected wild fry will have experienced the organochlorine load from the Baltic Sea, hatchery-reared fry were included in the studies as an additional control. The results show that the vascular defects observed in fry suffering from M74 are associated with reduced DNA-binding activity of HIF-1α and subsequent downregulation of its target gene vascular endothelial growth factor (VEGF). In addition, also AhR function is decreased in diseased fry making it unlikely that symptoms of M74-affected fry would be caused by an upregulation of xenobiotically induced AhR-dependent gene expression pathway

  19. Expression of hypoxia-inducible factor-1α and hepatocyte growth factor in development of fibrosis in the transplanted kidney

    DEFF Research Database (Denmark)

    Kellenberger, Terese; Marcussen, Niels; Nyengaard, Jens Randel

    2014-01-01

    Late renal graft loss is associated with interstitial fibrosis. Hypoxia-inducible factor-1α (HIF-1α) is thought to facilitate fibrosis through interaction with TGF-β1, while hepatocyte growth factor (HGF) may act antifibrotic in the kidney allograft. The aim of this study was to investigate...... transplantation, but an inverse significant correlation between the HGF expression and the fibrosis score 1 year after transplantation was shown. Even when adjusting for human leucocyte antigen mismatches, there was a significant relationship between fibrosis and HGF expression. Graft survival...... was not significantly correlated to HIF-1α or HGF at 1 year, although the trend was towards better graft survival with high HGF. HGF may have antifibrotic effects in human renal transplants. (Central.Denmark.Region.Committee number: 1-10-72-318-13)....

  20. Edaravone Improves Septic Cardiac Function by Inducing an HIF-1α/HO-1 Pathway

    Directory of Open Access Journals (Sweden)

    Chao He

    2018-01-01

    Full Text Available Septic myocardial dysfunction remains prevalent and raises mortality rate in patients with sepsis. During sepsis, tissues undergo tremendous oxidative stress which contributes critically to organ dysfunction. Edaravone, a potent radical scavenger, has been proved beneficial in ischemic injuries involving hypoxia-inducible factor- (HIF- 1, a key regulator of a prominent antioxidative protein heme oxygenase- (HO- 1. However, its effect in septic myocardial dysfunction remains unclarified. We hypothesized that edaravone may prevent septic myocardial dysfunction by inducing the HIF-1/HO-1 pathway. Rats were subjected to cecal ligation and puncture (CLP with or without edaravone infusion at three doses (50, 100, or 200 mg/kg, resp. before CLP and intraperitoneal injection of the HIF-1α antagonist, ME (15 mg/kg, after CLP. After CLP, rats had cardiac dysfunction, which was associated with deformed myocardium, augmented lipid peroxidation, and increased myocardial apoptosis and inflammation, along with decreased activities of catalase, HIF-1α, and HO-1 in the myocardium. Edaravone pretreatment dose-dependently reversed the changes, of which high dose most effectively improved cardiac function and survival rate of septic rats. However, inhibition of HIF-1α by ME demolished the beneficial effects of edaravone at high dose, reducing the survival rate of the septic rats without treatments. Taken together, edaravone, by inducing the HIF-1α/HO-1 pathway, suppressed oxidative stress and protected the heart against septic myocardial injury and dysfunction.

  1. The zebrafish miR-125c is induced under hypoxic stress via hypoxia-inducible factor 1α and functions in cellular adaptations and embryogenesis.

    Science.gov (United States)

    He, Yan; Huang, Chun-Xiao; Chen, Nan; Wu, Meng; Huang, Yan; Liu, Hong; Tang, Rong; Wang, Wei-Min; Wang, Huan-Ling

    2017-09-26

    Hypoxia is a unique environmental stress. Hypoxia inducible factor-lα (HIF-lα) is a major transcriptional regulator of cellular adaptations to hypoxic stress. MicroRNAs (miRNAs) as posttranscriptional gene expression regulators occupy a crucial role in cell survival under low-oxygen environment. Previous evidences suggested that miR-125c is involved in hypoxia adaptation, but its precise biological roles and the regulatory mechanism underlying hypoxic responses remain unknown. The present study showed that zebrafish miR-125c is upregulated by hypoxia in a Hif-lα-mediated manner in vitro and in vivo . Dual-luciferase assay revealed that cdc25a is a novel target of miR-125c. An inverse correlation between miR-125c and cdc25a was further confirmed in vivo , suggesting miR-125c as a crucial physiological inhibitor of cdc25a which responds to cellular hypoxia. Overexpression of miR-125c suppressed cell proliferation, led to cell cycle arrest at the G1 phase in ZF4 cells and induced apoptotic responses during embryo development. More importantly, miR-125c overexpression resulted in severe malformation and reduction of motility during zebrafish embryonic development. Taken together, we conclude that miR-125c plays a pivotal role in cellular adaptations to hypoxic stress at least in part through the Hif-1α/miR-125c/cdc25a signaling and has great impact on zebrafish early embryonic development.

  2. Sumoylation of hypoxia-inducible factor-1α ameliorates failure of brain stem cardiovascular regulation in experimental brain death.

    Directory of Open Access Journals (Sweden)

    Julie Y H Chan

    2011-03-01

    Full Text Available One aspect of brain death is cardiovascular deregulation because asystole invariably occurs shortly after its diagnosis. A suitable neural substrate for mechanistic delineation of this aspect of brain death resides in the rostral ventrolateral medulla (RVLM. RVLM is the origin of a life-and-death signal that our laboratory detected from blood pressure of comatose patients that disappears before brain death ensues. At the same time, transcriptional upregulation of heme oxygenase-1 in RVLM by hypoxia-inducible factor-1α (HIF-1α plays a pro-life role in experimental brain death, and HIF-1α is subject to sumoylation activated by transient cerebral ischemia. It follows that sumoylation of HIF-1α in RVLM in response to hypoxia may play a modulatory role on brain stem cardiovascular regulation during experimental brain death.A clinically relevant animal model that employed mevinphos as the experimental insult in Sprague-Dawley rat was used. Biochemical changes in RVLM during distinct phenotypes in systemic arterial pressure spectrum that reflect maintained or defunct brain stem cardiovascular regulation were studied. Western blot analysis, EMSA, ELISA, confocal microscopy and immunoprecipitation demonstrated that drastic tissue hypoxia, elevated levels of proteins conjugated by small ubiquitin-related modifier-1 (SUMO-1, Ubc9 (the only known conjugating enzyme for the sumoylation pathway or HIF-1α, augmented sumoylation of HIF-1α, nucleus-bound translocation and enhanced transcriptional activity of HIF-1α in RVLM neurons took place preferentially during the pro-life phase of experimental brain death. Furthermore, loss-of-function manipulations by immunoneutralization of SUMO-1, Ubc9 or HIF-1α in RVLM blunted the upregulated nitric oxide synthase I/protein kinase G signaling cascade, which sustains the brain stem cardiovascular regulatory machinery during the pro-life phase.We conclude that sumoylation of HIF-1α in RVLM ameliorates brain stem

  3. Preferential activation of HIF-2α adaptive signalling in neuronal-like cells in response to acute hypoxia.

    Directory of Open Access Journals (Sweden)

    Miguel A S Martín-Aragón Baudel

    Full Text Available Stroke causes severe neuronal damage as disrupted cerebral blood flow starves neurons of oxygen and glucose. The hypoxia inducible factors (HIF-1α and HIF-2α orchestrate oxygen homeostasis and regulate specific aspects of hypoxic adaptation. Here we show the importance of HIF-2α dependant signalling in neuronal adaptation to hypoxic insult. PC12 and NT2 cells were differentiated into neuronal-like cells using NGF and retinoic acid, and exposed to acute hypoxia (1% O2. Gene and protein expression was analysed by qPCR and immunoblotting and the neuronal-like phenotype was examined. PC12 and NT2 differentiation promoted neurite extension and expression of neuronal markers, NSE and KCC2. Induction of HIF-1α mRNA or protein was not detected in hypoxic neuronal-like cells, however marked induction of HIF-2α mRNA and protein expression was observed. Induction of HIF-1α target genes was also not detected in response to acute hypoxia, however significant induction of HIF-2α transcriptional targets was clearly evident. Furthermore, hypoxic insult dramatically reduced both neurite number and length, and attenuated expression of neuronal markers, NSE and KCC2. This correlated with an increase in expression of the neural progenitor and stem cell-like markers, CD44 and vimentin, suggesting HIF-2α molecular mechanisms could potentially promote regression of neuronal-like cells to a stem-like state and trigger neuronal recovery following ischaemic insult. Our findings suggest the HIF-2α pathway predominates over HIF-1α signalling in neuronal-like cells following acute hypoxia.

  4. Development of a novel fluorescent imaging probe for tumor hypoxia by use of a fusion protein with oxygen-dependent degradation domain of HIF-1α

    Science.gov (United States)

    Tanaka, Shotaro; Kizaka-Kondoh, Shinae; Harada, Hiroshi; Hiraoka, Masahiro

    2007-02-01

    More malignant tumors contain more hypoxic regions. In hypoxic tumor cells, expression of a series of hypoxiaresponsive genes related to malignant phenotype such as angiogenesis and metastasis are induced. Hypoxia-inducible factor-1 (HIF-1) is a master transcriptional activator of such genes, and thus imaging of hypoxic tumor cells where HIF-1 is active, is important in cancer therapy. We have been developing PTD-ODD fusion proteins, which contain protein transduction domain (PTD) and the VHL-mediated protein destruction motif in oxygen-dependent degradation (ODD) domain of HIF-1 alpha subunit (HIF-1α). Thus PTD-ODD fusion proteins can be delivered to any tissue in vivo through PTD function and specifically stabilized in hypoxic cells through ODD function. To investigate if PTD-ODD fusion protein can be applied to construct hypoxia-specific imaging probes, we first constructed a fluorescent probe because optical imaging enable us to evaluate a probe easily, quickly and economically in a small animal. We first construct a model fusion porein PTD-ODD-EGFP-Cy5.5 named POEC, which is PTD-ODD protein fused with EGFP for in vitro imaging and stabilization of fusion protein, and conjugated with a near-infrared dye Cy5.5. This probe is designed to be degraded in normoxic cells through the function of ODD domain and followed by quick clearance of free fluorescent dye. On the other hand, this prove is stabilized in hypoxic tumor cells and thus the dye is stayed in the cells. Between normoxic and hypoxic conditions, the difference in the clearance rate of the dye will reveals suited contrast for tumor-hypoxia imaging. The optical imaging probe has not been optimized yet but the results presented here exhibit a potential of PTD-ODD fusion protein as a hypoxia-specific imaging probe.

  5. IGF-1R Promotes Symmetric Self-Renewal and Migration of Alkaline Phosphatase+ Germ Stem Cells through HIF-2α-OCT4/CXCR4 Loop under Hypoxia

    Directory of Open Access Journals (Sweden)

    Yung-Che Kuo

    2018-02-01

    Full Text Available Summary: Hypoxia cooperates with endocrine signaling to maintain the symmetric self-renewal proliferation and migration of embryonic germline stem cells (GSCs. However, the lack of an appropriate in vitro cell model has dramatically hindered the understanding of the mechanism underlying this cooperation. Here, using a serum-free system, we demonstrated that hypoxia significantly induced the GSC mesenchymal transition, increased the expression levels of the pluripotent transcription factor OCT4 and migration-associated proteins (SDF-1, CXCR4, IGF-1, and IGF-1R, and activated the cellular expression and translocalization of the CXCR4-downstream proteins ARP3/pFAK. The underlying mechanism involved significant IGF-1/IGF-1R activation of OCT4/CXCR4 expression through HIF-2α regulation. Picropodophyllin-induced inhibition of IGF-1R phosphorylation significantly suppressed hypoxia-induced SDF-1/CXCR4 expression and cell migration. Furthermore, transactivation between IGF-1R and CXCR4 was involved. In summary, we demonstrated that niche hypoxia synergistically cooperates with its associated IGF-1R signaling to regulate the symmetric division (self-renewal proliferation and cell migration of alkaline phosphatase-positive GSCs through HIF-2α-OCT4/CXCR4 during embryogenesis. : In this article, Huang and colleagues demonstrate that niche hypoxia promotes symmetric self-renewal proliferation and migration of PGC-like CD49f+AP+GSCs through IGF-IR regulation. Using a serum-free culture system, the crosstalk between IGF-1R and CXCR4 signaling was discovered. This work demonstrated that embryonic hypoxia synergistically cooperated with IGF-1R signaling to regulate the symmetric self-renewal and migration of PGC-like GSCs through a HIF-2α–OCT4/CXCR4 loop. Keywords: hypoxia, niche, germline stem cells, self-renewal, migration, IGF-1R, HIF-2α, OCT4, SDF-1, CXCR4

  6. Neutralizing S1P inhibits intratumoral hypoxia, induces vascular remodelling and sensitizes to chemotherapy in prostate cancer

    Science.gov (United States)

    Ader, Isabelle; Golzio, Muriel; Andrieu, Guillaume; Zalvidea, Santiago; Richard, Sylvain; Sabbadini, Roger A.; Malavaud, Bernard; Cuvillier, Olivier

    2015-01-01

    Hypoxia promotes neovascularization, increased tumor growth, and therapeutic resistance. The transcription factor, hypoxia-inducible factor 1α (HIF-1α), has been reported as the master driver of adaptation to hypoxia. We previously identified the sphingosine kinase 1/sphingosine 1-phosphate (SphK1/S1P) pathway as a new modulator of HIF-1α under hypoxia. Taking advantage of a monoclonal antibody neutralizing extracellular S1P (sphingomab), we report that inhibition of S1P extracellular signaling blocks HIF-1α accumulation and activity in several cancer cell models exposed to hypoxia. In an orthotopic xenograft model of prostate cancer, we show that sphingomab reduces hypoxia and modifies vessel architecture within 5 days of treatment, leading to increased intratumoral blood perfusion. Supporting the notion that a transient vascular normalization of tumor vessels is the mechanism by which sphingomab exerts its effects, we demonstrate that administration of the antibody for 5 days before chemotherapy is more effective at local tumor control and metastatic dissemination than any other treatment scheduling. These findings validate sphingomab as a potential new normalization agent that could contribute to successful sensitization of hypoxic tumors to chemotherapy. PMID:25915662

  7. Effects of stem cell factor on hypoxia-inducible factor 1 alpha accumulation in human acute myeloid leukaemia and LAD2 mast cells.

    Directory of Open Access Journals (Sweden)

    Bernhard F Gibbs

    Full Text Available Stem cell factor (SCF is a hematopoietic growth factor that exerts its activity by signalling through the tyrosine kinase receptor known as Kit or CD117. SCF-Kit signalling is crucial for the survival, proliferation and differentiation of hematopoietic cells of myeloid lineage. Furthermore, since myeloid leukaemia cells express the Kit receptor, SCF may play an important role in myeloid leukaemia progression too. However, the mechanisms of this pathophysiological effect remain unclear. Recent evidence shows that SCF triggers accumulation of the inducible alpha subunit of hypoxia-inducible factor 1 (HIF-1 in hematopoietic cells--a transcription complex that plays a pivotal role in cellular adaptation to low oxygen availability. However, it is unknown how SCF impacts on HIF-1α accumulation in human myeloid leukaemia and mast cells. Here we show that SCF induces HIF-1α accumulation in THP-1 human myeloid leukaemia cells but not in LAD2 mast cells. We demonstrated that LAD2 cells have a more robust glutathione (GSH-dependent antioxidative system compared to THP-1 cells and are therefore protected against the actions of ROS generated in an SCF-dependent manner. BSO-induced GSH depletion led to a significant decrease in HIF-1α prolyl hydroxylase (PHD activity in THP-1 cells and to near attenuation of it in LAD2 cells. In THP-1 cells, SCF-induced HIF-1α accumulation is controlled via ERK, PI3 kinase/PKC-δ/mTOR-dependent and to a certain extent by redox-dependent mechanisms. These results demonstrate for the first time an important cross-talk of signalling pathways associated with HIF-1 activation--an important stage of the myeloid leukaemia cell life cycle.

  8. In vivo evidence suggesting reciprocal renal hypoxia-inducible factor-1 upregulation and signal transducer and activator of transcription 3 activation in response to hypoxic and non-hypoxic stimuli.

    Science.gov (United States)

    Nechemia-Arbely, Yael; Khamaisi, Mogher; Rosenberger, Christian; Koesters, Robert; Shina, Ahuva; Geva, Carmit; Shriki, Anat; Klaus, Stephen; Rosen, Seymour; Rose-John, Stefan; Galun, Eithan; Axelrod, Jonathan H; Heyman, Samuel N

    2013-04-01

    In vitro studies suggest that combined activation of hypoxia-inducible factor (HIF) and signal transducer and activator of transcription 3 (STAT3) promotes the hypoxia response. However, their interrelationship in vivo remains poorly defined. The present study investigated the possible relationship between HIF-1 upregulation and STAT3 activation in the rodent kidney in vivo. Activation of HIF-1 and STAT3 was analysed by immunohistochemical staining and western blot analysis in: (i) models of hypoxia-associated kidney injury induced by radiocontrast media or rhabdomyolysis; (ii) following activation of STAT3 by the interleukin (IL)-6-soluble IL-6 receptor complex; or (iii) following HIF-1α stabilization using hypoxic and non-hypoxic stimuli (mimosine, FG-4497, CO, CoCl(2)) and in targeted von Hippel-Lindau-knockout mice. Western blot analysis and immunostaining revealed marked induction of both transcription factors under all conditions tested, suggesting that in vivo STAT3 can trigger HIF and vice versa. Colocalization of HIF-1α and phosphorylated STAT3 was detected in some, but not all, renal cell types, suggesting that in some cells a paracrine mechanism may be responsible for the reciprocal activation of the two transcription factors. Nevertheless, in several cell types spatial concordance was observed under the majority of conditions tested, suggesting that HIF-1 and STAT3 may act as cotranscription factors. These in vivo studies suggest that, in response to renal hypoxic-stress, upregulation of HIF-1 and activation of STAT3 may be both reciprocal and cell type dependent. © 2013 The Authors Clinical and Experimental Pharmacology and Physiology © 2013 Wiley Publishing Asia Pty Ltd.

  9. Targeting HIF-2α as therapy for advanced cancers.

    Science.gov (United States)

    Murugesan, Thanabal; Rajajeyabalachandran, Gurukumari; Kumar, Swetha; Nagaraju, Shruthi; Kumar, Sooriya

    2018-05-14

    Hypoxia-inducible factors (HIF-1α, -2α -3α, and -β) are key factors that control hypoxia-induced carcinogenic pathways. HIF-1α is predominantly involved in the early stages of cancer, whereas HIF-2α is actively involved in the later stages; in addition, chronic (prolonged) rather than acute (short) hypoxia is a feature of metastasis and chemoresistance that occur during the later stages of cancer. Oncometabolites, onco-miRNAs, glucose deprivation, pseudohypoxia, cytokine/chemokine secretion, and some unique upstream proteins are involved in the signaling switch from HIF-1α to HIF-2α; thus, understanding this signaling switch is critical for the treatment of advanced cancer. In this review, we highlight data relating to HIF-2α rather than HIF-1α signaling in cancer pathways and discuss prospective drugs that target this important factor. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. [Effects of hypoxia inducible factor-1α on P311 and its influence on the migration of murine epidermal stem cells].

    Science.gov (United States)

    Xu, Z D; Li, H S; Wang, S; He, W F; Wu, J; Luo, G X

    2017-05-20

    Objective: To explore the effects of hypoxia inducible factor-1α (HIF-1α) on P311 and its influence on the migration of murine epidermal stem cells (ESCs) under hypoxia in vitro. Methods: Two kinds of murine ESCs were isolated and obtained from 15 neonatal wild-type C57BL/6J mice and 5 congeneric source P311 gene knock-out mice, respectively. The first passage of cells were used in the following experiments after morphologic observation and detection of expression of cell surface markers CD71 and CD49f with flow cytometer. (1) After cell scratch assay, according to the random number table (the same dividing method below), ESCs of P311 gene knock-out mice were divided into normoxia group (cells were cultured with complete medium in normoxic carbon dioxide incubator, and the subsequent normoxic treatments were the same) and hypoxia group (cells were cultured in hypoxic carbon dioxide incubator containing 1% oxygen, and the subsequent hypoxic treatments were the same), with 12 inserts in each group. ESCs of wild-type mice were divided into normoxia group, pure hypoxia group, dimethyl sulfoxide (DMSO) control group (2 μL DMSO solvent was added for 1 h of normoxia treatment before hypoxia treatment), HIF-1α inhibitor group (cells were treated with 11 μmol/L HIF-1 inhibitor of 2 μL under normoxia condition for 1 h before hypoxia treatment), HIF-1α stabilizer group (the cells were treated with 2 μmol/L FG-4592 of 2 μL under normoxia condition for 1 h before hypoxia treatment), with 12 inserts in each group. Three inserts of each time point in each group were adopted respectively to measure the residual width of scratch under inverted phase contrast microscope at post scratch hour (PSH) 0 (immediately), 12, 24, and 48. (2) After hypoxia treatment, the protein level of HIF-1α in ESCs of wild-type mice was detected by Western blotting at post hypoxia hour (PHH) 0, 12, 24, and 48. (3) ESCs of wild-type mice were divided into pure hypoxia group, DMSO control group

  11. Hypoxia-inducible factor-2α-dependent hypoxic induction of Wnt10b expression in adipogenic cells.

    Science.gov (United States)

    Park, Young-Kwon; Park, Bongju; Lee, Seongyeol; Choi, Kang; Moon, Yunwon; Park, Hyunsung

    2013-09-06

    Adipocyte hyperplasia and hypertrophy in obesity can lead to many changes in adipose tissue, such as hypoxia, metabolic dysregulation, and enhanced secretion of cytokines. In this study, hypoxia increased the expression of Wnt10b in both human and mouse adipogenic cells, but not in hypoxia-inducible factor (HIF)-2α-deficient adipogenic cells. Chromatin immunoprecipitation analysis revealed that HIF-2α, but not HIF-1α, bound to the Wnt10b enhancer region as well as upstream of the Wnt1 gene, which is encoded by an antisense strand of the Wnt10b gene. Hypoxia-conditioned medium (H-CM) induced phosphorylation of lipoprotein-receptor-related protein 6 as well as β-catenin-dependent gene expression in normoxic cells, which suggests that H-CM contains canonical Wnt signals. Furthermore, adipogenesis of both human mesenchymal stem cells and mouse preadipocytes was inhibited by H-CM even under normoxic conditions. These results suggest that O2 concentration gradients influence the formation of Wnt ligand gradients, which are involved in the regulation of pluripotency, cell proliferation, and cell differentiation.

  12. Up-regulation of hypoxia inducible factor-1α by cobalt chloride correlates with proliferation and apoptosis in PC-2 cells

    Directory of Open Access Journals (Sweden)

    Dai Zhi-Jun

    2012-03-01

    Full Text Available Abstract Background The exact mechanism of the effects of hypoxia on the proliferation and apoptosis in carcinoma cells is still conflicting. This study investigated the variation of hypoxia-inducible factor-1α(HIF-1α expression and the apoptosis effect of hypoxia stimulated by cobalt chloride (CoCl2 in pancreatic cancer PC-2 cells. Methods PC-2 cells were cultured with different concentration (50-200 μmol/L of CoCl2 after 24-120 hours to simulate hypoxia in vitro. The proliferation of PC-2 cells was examined by MTT assay. The cellular morphology of PC-2 cells were observed by light inverted microscope and transmission electron microscope(EM. The expression of HIF-1α on mRNA and protein level was measured by semi-quantitive RT-PCR and Western blot analysis. Apoptosis of PC-2 cells were demonstrated by flow cytometry with Annexin V-FITC/PI double staining. Results MTT assay showed that the proliferation of PC-2 cells were stimulated in the first 72 h, while after treated over 72 h, a dose- dependent inhibition of cell growth could be observed. By using transmission electron microscope, swollen chondrosomes, accumulated chromatin under the nuclear membrane and apoptosis bodies were observed. Flow cytometer(FCM analysis showed the apoptosis rate was correlated with the dosage of CoCl2. RT-PCR and Western blot analysis indicated that hypoxia could up-regulate the expression of HIF-1α on both mRNA and protein levels. Conclusion Hypoxic microenvironment stimulated by CoCl2 could effectively induce apoptosis and influence cell proliferation in PC-2 cells, the mechanism could be related to up-expression of HIF-1α.

  13. Hypoxia-inducible factor directs POMC gene to mediate hypothalamic glucose sensing and energy balance regulation.

    Directory of Open Access Journals (Sweden)

    Hai Zhang

    2011-07-01

    Full Text Available Hypoxia-inducible factor (HIF is a nuclear transcription factor that responds to environmental and pathological hypoxia to induce metabolic adaptation, vascular growth, and cell survival. Here we found that HIF subunits and HIF2α in particular were normally expressed in the mediobasal hypothalamus of mice. Hypothalamic HIF was up-regulated by glucose to mediate the feeding control of hypothalamic glucose sensing. Two underlying molecular pathways were identified, including suppression of PHDs by glucose metabolites to prevent HIF2α degradation and the recruitment of AMPK and mTOR/S6K to regulate HIF2α protein synthesis. HIF activation was found to directly control the transcription of POMC gene. Genetic approach was then employed to develop conditional knockout mice with HIF inhibition in POMC neurons, revealing that HIF loss-of-function in POMC neurons impaired hypothalamic glucose sensing and caused energy imbalance to promote obesity development. The metabolic effects of HIF in hypothalamic POMC neurons were independent of leptin signaling or pituitary ACTH pathway. Hypothalamic gene delivery of HIF counteracted overeating and obesity under conditions of nutritional excess. In conclusion, HIF controls hypothalamic POMC gene to direct the central nutrient sensing in regulation of energy and body weight balance.

  14. Hypoxia-Inducible Factor Directs POMC Gene to Mediate Hypothalamic Glucose Sensing and Energy Balance Regulation

    Science.gov (United States)

    Zhang, Hai; Zhang, Guo; Gonzalez, Frank J.; Park, Sung-min; Cai, Dongsheng

    2011-01-01

    Hypoxia-inducible factor (HIF) is a nuclear transcription factor that responds to environmental and pathological hypoxia to induce metabolic adaptation, vascular growth, and cell survival. Here we found that HIF subunits and HIF2α in particular were normally expressed in the mediobasal hypothalamus of mice. Hypothalamic HIF was up-regulated by glucose to mediate the feeding control of hypothalamic glucose sensing. Two underlying molecular pathways were identified, including suppression of PHDs by glucose metabolites to prevent HIF2α degradation and the recruitment of AMPK and mTOR/S6K to regulate HIF2α protein synthesis. HIF activation was found to directly control the transcription of POMC gene. Genetic approach was then employed to develop conditional knockout mice with HIF inhibition in POMC neurons, revealing that HIF loss-of-function in POMC neurons impaired hypothalamic glucose sensing and caused energy imbalance to promote obesity development. The metabolic effects of HIF in hypothalamic POMC neurons were independent of leptin signaling or pituitary ACTH pathway. Hypothalamic gene delivery of HIF counteracted overeating and obesity under conditions of nutritional excess. In conclusion, HIF controls hypothalamic POMC gene to direct the central nutrient sensing in regulation of energy and body weight balance. PMID:21814490

  15. The Factor Inhibiting HIF Asparaginyl Hydroxylase Regulates Oxidative Metabolism and Accelerates Metabolic Adaptation to Hypoxia.

    Science.gov (United States)

    Sim, Jingwei; Cowburn, Andrew S; Palazon, Asis; Madhu, Basetti; Tyrakis, Petros A; Macías, David; Bargiela, David M; Pietsch, Sandra; Gralla, Michael; Evans, Colin E; Kittipassorn, Thaksaon; Chey, Yu C J; Branco, Cristina M; Rundqvist, Helene; Peet, Daniel J; Johnson, Randall S

    2018-04-03

    Animals require an immediate response to oxygen availability to allow rapid shifts between oxidative and glycolytic metabolism. These metabolic shifts are highly regulated by the HIF transcription factor. The factor inhibiting HIF (FIH) is an asparaginyl hydroxylase that controls HIF transcriptional activity in an oxygen-dependent manner. We show here that FIH loss increases oxidative metabolism, while also increasing glycolytic capacity, and that this gives rise to an increase in oxygen consumption. We further show that the loss of FIH acts to accelerate the cellular metabolic response to hypoxia. Skeletal muscle expresses 50-fold higher levels of FIH than other tissues: we analyzed skeletal muscle FIH mutants and found a decreased metabolic efficiency, correlated with an increased oxidative rate and an increased rate of hypoxic response. We find that FIH, through its regulation of oxidation, acts in concert with the PHD/vHL pathway to accelerate HIF-mediated metabolic responses to hypoxia. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

  16. Expression of MUC17 is regulated by HIF1α-mediated hypoxic responses and requires a methylation-free hypoxia responsible element in pancreatic cancer.

    Directory of Open Access Journals (Sweden)

    Sho Kitamoto

    Full Text Available MUC17 is a type 1 membrane-bound glycoprotein that is mainly expressed in the digestive tract. Recent studies have demonstrated that the aberrant overexpression of MUC17 is correlated with the malignant potential of pancreatic ductal adenocarcinomas (PDACs; however, the exact regulatory mechanism of MUC17 expression has yet to be identified. Here, we provide the first report of the MUC17 regulatory mechanism under hypoxia, an essential feature of the tumor microenvironment and a driving force of cancer progression. Our data revealed that MUC17 was significantly induced by hypoxic stimulation through a hypoxia-inducible factor 1α (HIF1α-dependent pathway in some pancreatic cancer cells (e.g., AsPC1, whereas other pancreatic cancer cells (e.g., BxPC3 exhibited little response to hypoxia. Interestingly, these low-responsive cells have highly methylated CpG motifs within the hypoxia responsive element (HRE, 5'-RCGTG-3', a binding site for HIF1α. Thus, we investigated the demethylation effects of CpG at HRE on the hypoxic induction of MUC17. Treatment of low-responsive cells with 5-aza-2'-deoxycytidine followed by additional hypoxic incubation resulted in the restoration of hypoxic MUC17 induction. Furthermore, DNA methylation of HRE in pancreatic tissues from patients with PDACs showed higher hypomethylation status as compared to those from non-cancerous tissues, and hypomethylation was also correlated with MUC17 mRNA expression. Taken together, these findings suggested that the HIF1α-mediated hypoxic signal pathway contributes to MUC17 expression, and DNA methylation of HRE could be a determinant of the hypoxic inducibility of MUC17 in pancreatic cancer cells.

  17. Clinical Aspects of Hypoxia-inducible Factors in Colorectal Cancer

    DEFF Research Database (Denmark)

    Havelund, Birgitte Mayland; Spindler, Karen-Lise Garm; Sørensen, Flemming Brandt

    Clinical Aspects of Hypoxia-inducible Factors in Colorectal Cancer  Birgitte Mayland Havelund1,4 MD, Karen-Lise Garm Spindler1,4 MD, PhD, Flemming Brandt Sørensen2,4 MD, DMSc, Ivan Brandslund3 MD, DMSc, Anders Jakobsen1,4 MD, DMSc.1Department of Oncology, 2Pathology and 3Biochemistry, Vejle...... activates transcription of numerous genes associated with angiogenesis, ATP-metabolism, cell-proliferation, glycolysis and apoptosis. HIF-1α is over expressed in many malignant tumors and is reported to play an important role in tumor invasion and progression. The aim of this Ph.D. project is to investigate...... the predictive and prognostic value of HIF-1α in colorectal cancer.Materials and MethodsThe project is divided into 3 substudies:1. Biological and methodological aspects. The expression of HIF-1α measured by immunohistochemistry in paraffin embedded tissue is related to single nucleotide polymorphism (SNP...

  18. Therapeutic treatment with a novel hypoxia-inducible factor hydroxylase inhibitor (TRC160334 ameliorates murine colitis

    Directory of Open Access Journals (Sweden)

    Gupta R

    2014-01-01

    Full Text Available Ram Gupta,1 Anita R Chaudhary,2 Binita N Shah,1 Avinash V Jadhav,3 Shitalkumar P Zambad,1 Ramesh Chandra Gupta,4 Shailesh Deshpande,4 Vijay Chauthaiwale,4 Chaitanya Dutt4 1Department of Pharmacology, 2Cellular and Molecular Biology, 3Preclinical Safety Evaluation, 4Discovery, Torrent Research Centre, Torrent Pharmaceuticals Ltd, Gandhinagar, Gujarat, India Background and aim: Mucosal healing in inflammatory bowel disease (IBD can be achieved by improvement of intestinal barrier protection. Activation of hypoxia-inducible factor (HIF has been identified as a critical factor for barrier protection during mucosal insult and is linked with improvement in symptoms of colitis. Although prophylactic efficacy of HIF hydroxylase inhibitors in murine colitis have been established, its therapeutic efficacy in clinically relevant therapeutic settings have not been established. In the present study we aim to establish therapeutic efficacy of TRC160334, a novel HIF hydroxylase inhibitor, in animal models of colitis. Methods: The efficacy of TRC160334 was evaluated in two different mouse models of colitis by oral route. A prophylactic efficacy study was performed in a 2,4,6-trinitrobenzene sulfonic acid-induced mouse model of colitis representing human Crohn's disease pathology. Additionally, a therapeutic efficacy study was performed in a dextran sulfate sodium-induced mouse model of colitis, a model simulating human ulcerative colitis. Results: TRC160334 treatment resulted in significant improvement in disease end points in both models of colitis. TRC160334 treatment resulted into cytoprotective heatshock protein 70 induction in inflamed colon. TRC160334 successfully attenuated the rate of fall in body weight, disease activity index, and macroscopic and microscopic scores of colonic damage leading to overall improvement in study outcome. Conclusion: Our findings are the first to demonstrate that therapeutic intervention with a HIF hydroxylase inhibitor

  19. PACAP and VIP inhibit the invasiveness of glioblastoma cells exposed to hypoxia through the regulation of HIFs and EGFR expression

    OpenAIRE

    Grazia eMaugeri; Agata Grazia eD'Amico; Agata Grazia eD'Amico; Rita eReitano; Gaetano eMagro; Sebastiano eCavallaro; Salvatore eSalomone; Velia eD'Agata

    2016-01-01

    Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) through the binding of vasoactive intestinal peptide receptors (VIPRs), perform a wide variety of effects in human cancers, including glioblastoma multiforme (GBM). This tumor is characterized by extensive areas of hypoxia, which triggers the expression of hypoxia-inducible factors (HIFs). HIFs not only mediate angiogenesis but also tumor cell migration and invasion. Furthermore, HIFs activation...

  20. Pretreatment HIF-1α and GLUT-1 expressions do not correlate with outcome after preoperative chemoradiotherapy in rectal cancer

    DEFF Research Database (Denmark)

    Havelund, Birgitte Mayland; Sørensen, Flemming Brandt; Lindebjerg, Jan

    2011-01-01

    The aim of the present study was to investigate hypoxia-inducible factor 1α (HIF-1α) and glucose transporter-1 (GLUT-1) expressions as predictors of response and survival after chemoradiotherapy in pretreatment biopsy specimens from patients with rectal cancer.......The aim of the present study was to investigate hypoxia-inducible factor 1α (HIF-1α) and glucose transporter-1 (GLUT-1) expressions as predictors of response and survival after chemoradiotherapy in pretreatment biopsy specimens from patients with rectal cancer....

  1. Hypoxic induction of the regulator of G-protein signalling 4 gene is mediated by the hypoxia-inducible factor pathway.

    Directory of Open Access Journals (Sweden)

    Sam W Z Olechnowicz

    Full Text Available The transcriptional response to hypoxia is largely dependent on the Hypoxia Inducible Factors (HIF-1 and HIF-2 in mammalian cells. Many target genes have been characterised for these heterodimeric transcription factors, yet there is evidence that the full range of HIF-regulated genes has not yet been described. We constructed a TetON overexpression system in the rat pheochromocytoma PC-12 cell line to search for novel HIF and hypoxia responsive genes. The Rgs4 gene encodes the Regulator of G-Protein Signalling 4 (RGS4 protein, an inhibitor of signalling from G-protein coupled receptors, and dysregulation of Rgs4 is linked to disease states such as schizophrenia and cardiomyopathy. Rgs4 was found to be responsive to HIF-2α overexpression, hypoxic treatment, and hypoxia mimetic drugs in PC-12 cells. Similar responses were observed in human neuroblastoma cell lines SK-N-SH and SK-N-BE(2C, but not in endothelial cells, where Rgs4 transcript is readily detected but does not respond to hypoxia. Furthermore, this regulation was found to be dependent on transcription, and occurs in a manner consistent with direct HIF transactivation of Rgs4 transcription. However, no HIF binding site was detectable within 32 kb of the human Rgs4 gene locus, leading to the possibility of regulation by long-distance genomic interactions. Further research into Rgs4 regulation by hypoxia and HIF may result in better understanding of disease states such as schizophrenia, and also shed light on the other roles of HIF yet to be discovered.

  2. Hypoxic Induction of the Regulator of G-Protein Signalling 4 Gene Is Mediated by the Hypoxia-Inducible Factor Pathway

    Science.gov (United States)

    Olechnowicz, Sam W. Z.; Fedele, Anthony O.; Peet, Daniel J.

    2012-01-01

    The transcriptional response to hypoxia is largely dependent on the Hypoxia Inducible Factors (HIF-1 and HIF-2) in mammalian cells. Many target genes have been characterised for these heterodimeric transcription factors, yet there is evidence that the full range of HIF-regulated genes has not yet been described. We constructed a TetON overexpression system in the rat pheochromocytoma PC-12 cell line to search for novel HIF and hypoxia responsive genes. The Rgs4 gene encodes the Regulator of G-Protein Signalling 4 (RGS4) protein, an inhibitor of signalling from G-protein coupled receptors, and dysregulation of Rgs4 is linked to disease states such as schizophrenia and cardiomyopathy. Rgs4 was found to be responsive to HIF-2α overexpression, hypoxic treatment, and hypoxia mimetic drugs in PC-12 cells. Similar responses were observed in human neuroblastoma cell lines SK-N-SH and SK-N-BE(2)C, but not in endothelial cells, where Rgs4 transcript is readily detected but does not respond to hypoxia. Furthermore, this regulation was found to be dependent on transcription, and occurs in a manner consistent with direct HIF transactivation of Rgs4 transcription. However, no HIF binding site was detectable within 32 kb of the human Rgs4 gene locus, leading to the possibility of regulation by long-distance genomic interactions. Further research into Rgs4 regulation by hypoxia and HIF may result in better understanding of disease states such as schizophrenia, and also shed light on the other roles of HIF yet to be discovered. PMID:22970249

  3. Expression of hypoxia-inducible factor-1α and erythropoietin at corneal neovascularization in rats

    Directory of Open Access Journals (Sweden)

    Ji-Min Wang

    2014-12-01

    Full Text Available AIM: To describe the expression of hypoxia-inducible factor-1α(HIF-1αand erythropoietin(EPOin rats' corneal and evaluate its potential effect on corneal neovascularization(CNVgrowth. METHODS: The young SD rats(3mowas chosen and randomly divided into 2 groups, which were experimental group and normal control group. CNV model was established by alkali burn, and the length and area of CNV was observed everyday after operation by slit lamp. After that, the expression of HIF-1α and EPO was measured by SABC and RT-PCR methods at 1, 3, 5, 7, and 14d after alkali burn. The data was analyzed by SPSS 20.0. RESULTS: The area of CNV was increasing at 1, 3, 5, 7, and 14d after alkali burn, and the peak point appear at 7d. The growth speed was decreased after 14d. SABC method told us that no HIF-1α and very tiny amount EPO was detected at normal rats' corneal. The expression of the two factors increased at 1d after alkali burn in corneal epithelium and endoderm. The results of RT-PCR showed that a few amounts of HIF-1α and EPO mRNA were detected at normal group. The expression of the two factors was increased at 3d after alkali burn, and the peak value was found at 7d, however, it was decreased at 14d. Statistical difference was found at different time(PCONCLUSION: HIF-1α and EPO is closely related to CNV.

  4. Strategies To Assess Hypoxic/HIF-1-Active Cancer Cells for the Development of Innovative Radiation Therapy

    International Nuclear Information System (INIS)

    Yeom, Chan Joo; Zeng, Lihua; Zhu, Yuxi; Hiraoka, Masahiro; Harada, Hiroshi

    2011-01-01

    Local tumor recurrence and distant tumor metastasis frequently occur after radiation therapy and result in the death of cancer patients. These problems are caused, at least in part, by a tumor-specific oxygen-poor microenvironment, hypoxia. Oxygen-deprivation is known to inhibit the chemical ionization of both intracellular macro-molecules and water, etc., and thus reduce the cytotoxic effects of radiation. Moreover, DNA damage produced by free radicals is known to be more repairable under hypoxia than normoxia. Hypoxia is also known to induce biological tumor radioresistance through the activation of a transcription factor, hypoxia-inducible factor 1 (HIF-1). Several potential strategies have been devised in radiation therapy to overcome these problems; however, they have not yet achieved a complete remission. It is essential to reveal the intratumoral localization and dynamics of hypoxic/HIF-1-active tumor cells during tumor growth and after radiation therapy, then exploit the information to develop innovative therapeutic strategies, and finally damage radioresistant cells. In this review, we overview problems caused by hypoxia/HIF-1-active cells in radiation therapy for cancer and introduce strategies to assess intratumoral hypoxia/HIF-1 activity

  5. Strategies To Assess Hypoxic/HIF-1-Active Cancer Cells for the Development of Innovative Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yeom, Chan Joo [Group of Radiation and Tumor Biology, Career-Path Promotion Unit for Young Life Scientists, Kyoto University, Yoshida Konoe-cho, Sakyo-ku, Kyoto 606-8501 (Japan); Zeng, Lihua; Zhu, Yuxi [Group of Radiation and Tumor Biology, Career-Path Promotion Unit for Young Life Scientists, Kyoto University, Yoshida Konoe-cho, Sakyo-ku, Kyoto 606-8501 (Japan); Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507 (Japan); Hiraoka, Masahiro [Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507 (Japan); Harada, Hiroshi, E-mail: hharada@kuhp.kyoto-u.ac.jp [Group of Radiation and Tumor Biology, Career-Path Promotion Unit for Young Life Scientists, Kyoto University, Yoshida Konoe-cho, Sakyo-ku, Kyoto 606-8501 (Japan)

    2011-09-15

    Local tumor recurrence and distant tumor metastasis frequently occur after radiation therapy and result in the death of cancer patients. These problems are caused, at least in part, by a tumor-specific oxygen-poor microenvironment, hypoxia. Oxygen-deprivation is known to inhibit the chemical ionization of both intracellular macro-molecules and water, etc., and thus reduce the cytotoxic effects of radiation. Moreover, DNA damage produced by free radicals is known to be more repairable under hypoxia than normoxia. Hypoxia is also known to induce biological tumor radioresistance through the activation of a transcription factor, hypoxia-inducible factor 1 (HIF-1). Several potential strategies have been devised in radiation therapy to overcome these problems; however, they have not yet achieved a complete remission. It is essential to reveal the intratumoral localization and dynamics of hypoxic/HIF-1-active tumor cells during tumor growth and after radiation therapy, then exploit the information to develop innovative therapeutic strategies, and finally damage radioresistant cells. In this review, we overview problems caused by hypoxia/HIF-1-active cells in radiation therapy for cancer and introduce strategies to assess intratumoral hypoxia/HIF-1 activity.

  6. The zebrafish miR-462/miR-731 cluster is induced under hypoxic stress via hypoxia-inducible factor 1α and functions in cellular adaptations.

    Science.gov (United States)

    Huang, Chun-Xiao; Chen, Nan; Wu, Xin-Jie; Huang, Cui-Hong; He, Yan; Tang, Rong; Wang, Wei-Min; Wang, Huan-Ling

    2015-12-01

    Hypoxia, a unique and essential environmental stress, evokes highly coordinated cellular responses, and hypoxia-inducible factor (HIF) 1 in the hypoxia signaling pathway, an evolutionarily conserved cellular signaling pathway, acts as a master regulator of the transcriptional response to hypoxic stress. MicroRNAs (miRNAs), a major class of posttranscriptional gene expression regulators, also play pivotal roles in orchestrating hypoxia-mediated cellular adaptations. Here, global miRNA expression profiling and quantitative real-time PCR indicated that the up-regulation of the miR-462/miR-731 cluster in zebrafish larvae is induced by hypoxia. It was further validated that miR-462 and miR-731 are up-regulated in a Hif-1α-mediated manner under hypoxia and specifically target ddx5 and ppm1da, respectively. Overexpression of miR-462 and miR-731 represses cell proliferation through blocking cell cycle progress of DNA replication, and induces apoptosis. In situ detection revealed that the miR-462/miR-731 cluster is highly expressed in a consistent and ubiquitous manner throughout the early developmental stages. Additionally, the transcripts become restricted to the notochord, pharyngeal arch, liver, and gut regions from postfertilization d 3 to 5. These data highlight a previously unidentified role of the miR-462/miR-731 cluster as a crucial signaling mediator for hypoxia-mediated cellular adaptations and provide some insights into the potential function of the cluster during embryonic development. © FASEB.

  7. General applicability of chicken egg yolk antibodies: the performance of IgY immunoglobulins raised against the hypoxia-inducible factor 1alpha

    OpenAIRE

    Camenisch, G; Tini, M; Chilov, D; Kvietikova, I; Srinivas, V; Caro, J; Spielmann, P; Wenger, R H; Gassmann, M

    1999-01-01

    Avian embryos and neonates acquire passive immunity by transferring maternal immunoglobulins from serum to egg yolk. Despite being a convenient source of antibodies, egg yolk immunoglobulins (IgY) from immunized hens have so far received scant attention in research. Here we report the generation and rapid isolation of IgY from the egg yolk of hens immunized against the alpha subunit of the human hypoxia-inducible factor 1 (HIF-1alpha). Anti-HIF-1alpha IgY antibodies were affinity purified and...

  8. Aromatic Hydrocarbon Receptor Suppresses Prostate Cancer Bone Metastasis Cells-Induced Vasculogenesis of Endothelial Progenitor Cells under Hypoxia

    Directory of Open Access Journals (Sweden)

    Shuai Huang

    2016-07-01

    Full Text Available Background/Aims: Hypoxia leads to the development of neovascularization in solid tumor by regulating VEGF expression. Aromatic hydrocarbon receptor (AHR, a receptor for dioxin-like compounds, functions as a transcription factor through dimerization with hypoxia-inducible factors 1β (HIF-1β and inhibits the secretion of vascular endothelial growth factor (VEGF. The purpose of this study was to explore whether AHR can suppress hypoxia-induced VEGF production in prostate bone metastasis cells and repress neovascularization in endothelial progenitor cells (EPCs, and, if so, through what mechanisms. Methods: PC-3 or LNCaP cells induced angiogenesis was detected by Matrigel-based tube formation assay, mRNA expression levels was measured by qRT-PCR, VEGF secretion level was determined by ELISA assay, respectively. Results: AHR activation inhibits hypoxia-induced adhesiveness and vasculogenesis of EPCs induced by PC-3 or LNCaP cells under hypoxia. Moreover, AHR activation suppressed hypoxia-induced VEGF production in PC-3 and LNCaP cells (48 ± 14% in PC-3, p = 0.000; 41 ± 14% in LNCaP, p = 0.000 by attenuating HIF-1α and HIF-1β level that in turn diminished the angiogenic ability of EPCs in vitro. Furthermore, we found the mRNA level of hypoxia-inducible factors 1α (HIF-1α (1.54 ± 0.13 fold in PC-3, p = 0.002, 1.62 ± 0.12 fold in LNCaP, p = 0.001 and HIF-1β (1.67 ± 0.23 fold in PC-3, p = 0.007; 1.75 ± 0.26 fold in LNCaP, p=0.008 were upregulated in prostate cancer bone metastasis PC-3 and LNCaP cell lines in response to hypoxia, and revealed that the regulation of VEGF by HIF-1α and HIF-1β was possibly mediated by the activation of phosphatidylinositol 3-kinase pathway. Conclusion: By providing a mechanistic insight into the modulation of neovascularization by AHR ligand, we suggest that AHR ligand has a strong potential of being a new therapeutic agent with applications in the field of bone metastatic prostate cancer.

  9. Chronic intermittent hypoxia induces atherosclerosis via activation of adipose angiopoietin-like 4.

    Science.gov (United States)

    Drager, Luciano F; Yao, Qiaoling; Hernandez, Karen L; Shin, Mi-Kyung; Bevans-Fonti, Shannon; Gay, Jason; Sussan, Thomas E; Jun, Jonathan C; Myers, Allen C; Olivecrona, Gunilla; Schwartz, Alan R; Halberg, Nils; Scherer, Philipp E; Semenza, Gregg L; Powell, David R; Polotsky, Vsevolod Y

    2013-07-15

    Obstructive sleep apnea is a risk factor for dyslipidemia and atherosclerosis, which have been attributed to chronic intermittent hypoxia (CIH). Intermittent hypoxia inhibits a key enzyme of lipoprotein clearance, lipoprotein lipase, and up-regulates a lipoprotein lipase inhibitor, angiopoietin-like 4 (Angptl4), in adipose tissue. The effects and mechanisms of Angptl4 up-regulation in sleep apnea are unknown. To examine whether CIH induces dyslipidemia and atherosclerosis by increasing adipose Angptl4 via hypoxia-inducible factor-1 (HIF-1). ApoE(-/-) mice were exposed to intermittent hypoxia or air for 4 weeks while being treated with Angptl4-neutralizing antibody or vehicle. In vehicle-treated mice, hypoxia increased adipose Angptl4 levels, inhibited adipose lipoprotein lipase, increased fasting levels of plasma triglycerides and very low density lipoprotein cholesterol, and increased the size of atherosclerotic plaques. The effects of CIH were abolished by the antibody. Hypoxia-induced increases in plasma fasting triglycerides and adipose Angptl4 were not observed in mice with germline heterozygosity for a HIF-1α knockout allele. Transgenic overexpression of HIF-1α in adipose tissue led to dyslipidemia and increased levels of adipose Angptl4. In cultured adipocytes, constitutive expression of HIF-1α increased Angptl4 levels, which was abolished by siRNA. Finally, in obese patients undergoing bariatric surgery, the severity of nocturnal hypoxemia predicted Angptl4 levels in subcutaneous adipose tissue. HIF-1-mediated increase in adipose Angptl4 and the ensuing lipoprotein lipase inactivation may contribute to atherosclerosis in patients with sleep apnea.

  10. Cell physiology regulation by hypoxia inducible factor-1: Targeting oxygen-related nanomachineries of hypoxic cells.

    Science.gov (United States)

    Eskandani, Morteza; Vandghanooni, Somayeh; Barar, Jaleh; Nazemiyeh, Hossein; Omidi, Yadollah

    2017-06-01

    Any dysfunctionality in maintaining the oxygen homeostasis by mammalian cells may elicit hypoxia/anoxia, which results in inescapable oxidative stress and possible subsequent detrimental impacts on certain cells/tissues with high demands to oxygen molecules. The ischemic damage in turn can trigger initiation of a number of diseases including organs ischemia, metabolic disorders, inflammatory diseases, different types of malignancies, and alteration in wound healing process. Thus, full comprehension of molecular mechanism(s) and cellular physiology of the oxygen homeostasis is the cornerstone of the mammalian cells metabolism, energetic pathways and health and disease conditions. An imbalance in oxygen content within the cellular microenvironment activates a cascade of molecular events that are often compensated, otherwise pathologic condition occurs through a complexed network of biomolecules. Hypoxia inducible factor-1 (HIF-1) plays a key transcriptional role in the adaptation of cell physiology in relation with the oxygen content within a cell. In this current study, we provide a comprehensive review on the molecular mechanisms of oxygen sensing and homeostasis and the impacts of HIF-1 in hypoxic/anoxic conditions. Moreover, different molecular and biochemical responses of the cells to the surrounding environment are discussed in details. Finally, modern technological approaches for targeting the hypoxia related proteins are articulated. Copyright © 2017. Published by Elsevier B.V.

  11. Investigating the Regulation and Potential Role of Nonhypoxic Hypoxia Inducible Factor 1 (HIF 1) in Aromatase Inhibitor Resistant Breast Cancer

    Science.gov (United States)

    2015-12-01

    hypoxia response element ( HRE , 5’-GCGTG- 3’) occurs under basal conditions in LTLTCa cells and is significantly decreased by treatment with HER2...inhibitor lapatinib. Experiments to accomplish this task for vimentin were completed and reported in the 2014 annual summary. A potential HRE was located... HRE to which HIF-1 binds, were used for real-time PCR. ChIP real-time PCR results are expressed as the fold increase, compared with vehicle-treated

  12. Developmental Expression and Hypoxic Induction of Hypoxia Inducible Transcription Factors in the Zebrafish.

    Science.gov (United States)

    Köblitz, Louise; Fiechtner, Birgit; Baus, Katharina; Lussnig, Rebecca; Pelster, Bernd

    2015-01-01

    The hypoxia inducible transcription factor (HIF) has been shown to coordinate the hypoxic response of vertebrates and is expressed in three different isoforms, HIF-1α, HIF-2α and HIF-3α. Knock down of either Hif-1α or Hif-2α in mice results in lethality in embryonic or perinatal stages, suggesting that this transcription factor is not only controlling the hypoxic response, but is also involved in developmental phenomena. In the translucent zebrafish embryo the performance of the cardiovascular system is not essential for early development, therefore this study was designed to analyze the expression of the three Hif-isoforms during zebrafish development and to test the hypoxic inducibility of these transcription factors. To complement the existing zfHif-1α antibody we expressed the whole zfHif-2α protein and used it for immunization and antibody generation. Similarly, fragments of the zfHif-3α protein were used for immunization and generation of a zfHif-3α specific antibody. To demonstrate presence of the Hif-isoforms during development [between 1 day post fertilization (1 dpf) and 9 dpf] affinity-purified antibodies were used. Hif-1α protein was present under normoxic conditions in all developmental stages, but no significant differences between the different developmental stages could be detected. Hif-2α was also present from 1 dpf onwards, but in post hatching stages (between 5 and 9 dpf) the expression level was significantly higher than prior to hatching. Similarly, Hif-3α was expressed from 1 dpf onwards, and the expression level significantly increased until 5 dpf, suggesting that Hif-2α and Hif-3α play a particular role in early development. Hypoxic exposure (oxygen partial pressure = 5 kPa) in turn caused a significant increase in the level of Hif-1α protein even at 1 dpf and in later stages, while neither Hif-2α nor Hif-3α protein level were affected. In these early developmental stages Hif-1α therefore appears to be more important for

  13. Expression of Hypoxia-Associated Protein HIF-1α in Follicular Thyroid Cancer is Associated with Distant Metastasis.

    Science.gov (United States)

    Klaus, Aumayr; Fathi, Osmen; Tatjana, Traub-Weidinger; Bruno, Niederle; Oskar, Koperek

    2018-04-01

    Follicular thyroid carcinomas (FTCs) are the second most common malignant neoplasia of the thyroid and in general its prognosis is quite favorable. However, the occurrence of metastases or non-responsiveness to radioiodine therapy worsens the prognosis considerably. We evaluated immunohistochemically the expression of hypoxia-associated proteins by hypoxia-induced factor 1α (HIF-1α), the stroma-remodeling marker Tenascin C, as well as markers for the epithelial-mesenchymal transition (EMT), namely E-cadherin and slug in a series of 59 sporadic FTCs. In addition, various clinicopathologic parameters were assessed like TNM-staging, age, tumor size as well as tumor characteristics like desmoplasia, necrosis, and calcification. Overexpression of HIF-1α was seen in 29 of 59 tumors (49.2%) including 21 (35.6%) FTC with strong expression of tumor cell groups. HIF-1α correlated significantly with metastasis (p test), degree of desmoplasia (p = 0.042, Kruskal-Wallis test), tenascin C expression (p = 0.042, Kruskal-Wallis test), calcification (p Kruskal-Wallis test), necrosis (p = 0.002), age (p = 0.011, Kruskal-Wallis test) and tumor stage UICC (p = 0.022, Kruskal-Wallis test). Furthermore, metastasis was associated with the degree of desmoplasia (p = 0.014; Fisher's exact test), calcification (p = 0.008, Fisher's exact test), necrosis (p = 0.042, Fisher's exact test), tumor size (p = 0.015, Mann-Whitney U test), and age (p = 0.001, Mann-Whitney U test). In a Cox proportional hazards model, only metastasis remained as an independent risk factor for overall survival (hazard rate: 10.2 [95% CI, 02.19 to 47.26]; p = 0.003). Our data suggest that HIF-1α plays a critical role in the remodeling of the extracellular matrix as well as metastasizing process of follicular thyroid carcinoma and targeting hypoxia-associated and -regulated proteins may be considered as potential targets for personalized medicine.

  14. Effect of Hypoxia-Inducible Factor 1α on Early Healing in Extraction Sockets

    Directory of Open Access Journals (Sweden)

    Hyun-Chang Lim

    2018-01-01

    Full Text Available The aim of the present study was to investigate the effect of hypoxia-inducible factor 1α (HIF1A on the early healing (4 weeks of extraction sockets exhibiting partial loss of the labial bone. Two extraction sockets of the maxillary incisors from each of six dogs were assigned to two treatment modalities: deproteinized bovine bone mineral (i with 10% collagen (DBBM-C soaked with HIF1A and covered by a collagen membrane (CM (HIF group or (ii treated with DBBM-C only and covered by a CM (control group. Microcomputed tomography revealed some degree of collapse of the labial contour. The totally augmented volume and new bone volume did not differ significantly between two groups (P>0.05. The histological analysis revealed that the apical area of the socket was mostly filled with newly formed bone, while there was less newly formed bone in the coronal area and incomplete cortex formation. The histomorphometric analysis revealed that the area of newly formed bone was significantly larger in the HIF group than the control group (12.16±3.04 versus 9.48±2.01 mm2, P<0.05, while there was no significant intergroup difference in the total augmented area. In conclusion, even though DBBM-C soaked with HIF1A enhanced histomorphometric bone formation, this intervention did not demonstrate superiority in preventing ridge shrinkage compared to DBBM-C alone. Clinical relevance of these findings should be further studied.

  15. Baicalin inhibits hypoxia-induced pulmonary artery smooth muscle cell proliferation via the AKT/HIF-1α/p27-associated pathway.

    Science.gov (United States)

    Zhang, Lin; Pu, Zhichen; Wang, Junsong; Zhang, Zhifeng; Hu, Dongmei; Wang, Junjie

    2014-05-09

    Baicalin, a flavonoid compound purified from the dry roots of Scutellaria baicalensis Georgi, has been shown to possess various pharmacological actions. Previous studies have revealed that baicalin inhibits the growth of cancer cells through the induction of apoptosis. Pulmonary arterial hypertension (PAH) is a devastating disease characterized by enhanced pulmonary artery smooth muscle cell (PASMCs) proliferation and suppressed apoptosis. However, the potential mechanism of baicalin in the regulation of PASMC proliferation and the prevention of cardiovascular diseases remains unexplored. To test the effects of baicalin on hypoxia, we used rats treated with or without baicalin (100 mg·kg⁻¹ each rat) at the beginning of the third week after hypoxia. Hemodynamic and pulmonary pathomorphology data showed that right ventricular systolic pressures (RVSP), the weight of the right ventricle/left ventricle plus septum (RV/LV + S) ratio and the medial width of pulmonary arterioles were much higher in chronic hypoxia. However, baicalin treatment repressed the elevation of RVSP, RV/LV + S and attenuated the pulmonary vascular structure remodeling (PVSR) of pulmonary arterioles induced by chronic hypoxia. Additionally, baicalin (10 and 20 μmol·L⁻¹) treatment suppressed the proliferation of PASMCs and attenuated the expression of hypoxia-inducible factor-α (HIF-α) under hypoxia exposure. Meanwhile, baicalin reversed the hypoxia-induced reduction of p27 and increased AKT/protein kinase B phosphorylation p-AKT both in vivo and in vitro. These results suggested that baicalin could effectively attenuate PVSR and hypoxic pulmonary hypertension.

  16. Differential regulation of HIF-1α and HIF-2α in neuroblastoma: Estrogen-related receptor alpha (ERRα) regulates HIF2A transcription and correlates to poor outcome

    International Nuclear Information System (INIS)

    Hamidian, Arash; Stedingk, Kristoffer von; Munksgaard Thorén, Matilda; Mohlin, Sofie; Påhlman, Sven

    2015-01-01

    Hypoxia-inducible factors (HIFs) are differentially regulated in tumor cells. While the current paradigm supports post-translational regulation of the HIF-α subunits, we recently showed that hypoxic HIF-2α is also transcriptionally regulated via insulin-like growth factor (IGF)-II in the childhood tumor neuroblastoma. Here, we demonstrate that transcriptional regulation of HIF-2α seems to be restricted to neural cell-derived tumors, while HIF-1α is canonically regulated at the post-translational level uniformly across different tumor forms. Enhanced expression of HIF2A mRNA at hypoxia is due to de novo transcription rather than increased mRNA stability, and chemical stabilization of the HIF-α proteins at oxygen-rich conditions unexpectedly leads to increased HIF2A transcription. The enhanced HIF2A levels do not seem to be dependent on active HIF-1. Using a transcriptome array approach, we identified members of the Peroxisome proliferator-activated receptor gamma coactivator (PGC)/Estrogen-related receptor (ERR) complex families as potential regulators of HIF2A. Knockdown or inhibition of one of the members, ERRα, leads to decreased expression of HIF2A, and high expression of the ERRα gene ESRRA correlates with poor overall and progression-free survival in a clinical neuroblastoma material consisting of 88 tumors. Thus, targeting of ERRα and pathways regulating transcriptional HIF-2α are promising therapeutic avenues in neuroblastoma. - Highlights: • Transcriptional control of HIF-2α is restricted to neural cell-derived tumors. • Enhanced transcription of HIF2A is not due to increased mRNA stability. • Chemical stabilization of the HIF-α subunits leads to increased HIF2A transcription. • ERRα regulates HIF2A mRNA expression in neuroblastoma. • High expression of ESRRA correlates to poor outcome in neuroblastoma

  17. Differential regulation of HIF-1α and HIF-2α in neuroblastoma: Estrogen-related receptor alpha (ERRα) regulates HIF2A transcription and correlates to poor outcome

    Energy Technology Data Exchange (ETDEWEB)

    Hamidian, Arash; Stedingk, Kristoffer von; Munksgaard Thorén, Matilda; Mohlin, Sofie; Påhlman, Sven, E-mail: sven.pahlman@med.lu.se

    2015-06-05

    Hypoxia-inducible factors (HIFs) are differentially regulated in tumor cells. While the current paradigm supports post-translational regulation of the HIF-α subunits, we recently showed that hypoxic HIF-2α is also transcriptionally regulated via insulin-like growth factor (IGF)-II in the childhood tumor neuroblastoma. Here, we demonstrate that transcriptional regulation of HIF-2α seems to be restricted to neural cell-derived tumors, while HIF-1α is canonically regulated at the post-translational level uniformly across different tumor forms. Enhanced expression of HIF2A mRNA at hypoxia is due to de novo transcription rather than increased mRNA stability, and chemical stabilization of the HIF-α proteins at oxygen-rich conditions unexpectedly leads to increased HIF2A transcription. The enhanced HIF2A levels do not seem to be dependent on active HIF-1. Using a transcriptome array approach, we identified members of the Peroxisome proliferator-activated receptor gamma coactivator (PGC)/Estrogen-related receptor (ERR) complex families as potential regulators of HIF2A. Knockdown or inhibition of one of the members, ERRα, leads to decreased expression of HIF2A, and high expression of the ERRα gene ESRRA correlates with poor overall and progression-free survival in a clinical neuroblastoma material consisting of 88 tumors. Thus, targeting of ERRα and pathways regulating transcriptional HIF-2α are promising therapeutic avenues in neuroblastoma. - Highlights: • Transcriptional control of HIF-2α is restricted to neural cell-derived tumors. • Enhanced transcription of HIF2A is not due to increased mRNA stability. • Chemical stabilization of the HIF-α subunits leads to increased HIF2A transcription. • ERRα regulates HIF2A mRNA expression in neuroblastoma. • High expression of ESRRA correlates to poor outcome in neuroblastoma.

  18. BAY 87-2243, a highly potent and selective inhibitor of hypoxia-induced gene activation has antitumor activities by inhibition of mitochondrial complex I

    International Nuclear Information System (INIS)

    Ellinghaus, Peter; Heisler, Iring; Unterschemmann, Kerstin; Haerter, Michael; Beck, Hartmut; Greschat, Susanne; Ehrmann, Alexander; Summer, Holger; Flamme, Ingo; Oehme, Felix; Thierauch, Karlheinz; Michels, Martin; Hess-Stumpp, Holger; Ziegelbauer, Karl

    2013-01-01

    The activation of the transcription factor hypoxia-inducible factor-1 (HIF-1) plays an essential role in tumor development, tumor progression, and resistance to chemo- and radiotherapy. In order to identify compounds targeting the HIF pathway, a small molecule library was screened using a luciferase-driven HIF-1 reporter cell line under hypoxia. The high-throughput screening led to the identification of a class of aminoalkyl-substituted compounds that inhibited hypoxia-induced HIF-1 target gene expression in human lung cancer cell lines at low nanomolar concentrations. Lead structure BAY 87-2243 was found to inhibit HIF-1α and HIF-2α protein accumulation under hypoxic conditions in non-small cell lung cancer (NSCLC) cell line H460 but had no effect on HIF-1α protein levels induced by the hypoxia mimetics desferrioxamine or cobalt chloride. BAY 87-2243 had no effect on HIF target gene expression levels in RCC4 cells lacking Von Hippel–Lindau (VHL) activity nor did the compound affect the activity of HIF prolyl hydroxylase-2. Antitumor activity of BAY 87-2243, suppression of HIF-1α protein levels, and reduction of HIF-1 target gene expression in vivo were demonstrated in a H460 xenograft model. BAY 87-2243 did not inhibit cell proliferation under standard conditions. However under glucose depletion, a condition favoring mitochondrial ATP generation as energy source, BAY 87-2243 inhibited cell proliferation in the nanomolar range. Further experiments revealed that BAY 87-2243 inhibits mitochondrial complex I activity but has no effect on complex III activity. Interference with mitochondrial function to reduce hypoxia-induced HIF-1 activity in tumors might be an interesting therapeutic approach to overcome chemo- and radiotherapy-resistance of hypoxic tumors

  19. Regulation of glucose transporter protein-1 and vascular endothelial growth factor by hypoxia inducible factor 1α under hypoxic conditions in Hep-2 human cells.

    Science.gov (United States)

    Xu, Ou; Li, Xiaoming; Qu, Yongtao; Liu, Shuang; An, Jie; Wang, Maoxin; Sun, Qingjia; Zhang, Wen; Lu, Xiuying; Pi, Lihong; Zhang, Min; Shen, Yupeng

    2012-12-01

    The present study evaluated the regulation of glucose transporter protein-1 (Glut-1) and vascular endothelial growth factor (VEGF) by hypoxia inducible factor 1α (HIF-1α) under hypoxic conditions in Hep-2 human cells to explore the feasibility of these three genes as tumor markers. Hep-2 cells were cultured under hypoxic and normoxic conditions for 6, 12, 24, 36 and 48 h. The proliferation of Hep-2 cells was evaluated using an MTT assay. The protein and mRNA expression levels of HIF-1α, Glut-1 and VEGF were detected using the S-P immunocytochemical method, western blotting and reverse transcription polymerase chain reaction (RT-PCR). The results revealed that the expression levels of HIF-1α, Glut-1 and VEGF protein in Hep-2 cells were significantly elevated under hypoxic conditions compared with those under normoxic conditions over 36 h. Under hypoxic conditions, mRNA levels of HIF-1α were stable, while mRNA levels of Glut-1 and VEGF changed over time. In conclusion, Glut-1 and VEGF were upregulated by HIF-1α under hypoxic conditions in a time-dependent manner in Hep-2 cells and their co-expression serves as a tumor marker.

  20. Loss of hypoxia-inducible factor 2 alpha in the lung alveolar epithelium of mice leads to enhanced eosinophilic inflammation in cobalt-induced lung injury.

    Science.gov (United States)

    Proper, Steven P; Saini, Yogesh; Greenwood, Krista K; Bramble, Lori A; Downing, Nathaniel J; Harkema, Jack R; Lapres, John J

    2014-02-01

    Hard metal lung disease (HMLD) is an occupational lung disease specific to inhalation of cobalt-containing particles whose mechanism is largely unknown. Cobalt is a known hypoxia mimic and stabilizer of the alpha subunits of hypoxia-inducible factors (HIFs). Previous work revealed that though HIF1α contrib utes to cobalt toxicity in vitro, loss of HIF1α in the alveolar epithelial cells does not provide in vivo protection from cobalt-induced lung inflammation. HIF1α and HIF2α show unique tissue expression profiles, and HIF2α is known to be the predominant HIF mRNA isoform in the adult lung. Thus, if HIF2α activation by cobalt contributes to pathophysiology of HMLD, we hypothesized that loss of HIF2α in lung epithelium would provide protection from cobalt-induced inflammation. Mice with HIF2α-deficiency in Club and alveolar type II epithelial cells (ATIIs) (HIF2α(Δ/Δ)) were exposed to cobalt (60 µg/day) or saline using a subacute occupational exposure model. Bronchoalveolar lavage cellularity, cytokines, qRT-PCR, and histopathology were analyzed. Results show that loss of HIF2α leads to enhanced eosinophilic inflammation and increased goblet cell metaplasia. Additionally, control mice demonstrated a mild recovery from cobalt-induced lung injury compared with HIF2α(Δ/Δ) mice, suggesting a role for epithelial HIF2α in repair mechanisms. The expression of important cytokines, such as interleukin (IL)-5 and IL-10, displayed significant differences following cobalt exposure when HIF2α(Δ/Δ) and control mice were compared. In summary, our data suggest that although loss of HIF2α does not afford protection from cobalt-induced lung inflammation, epithelial HIF2α signaling does play an important role in modulating the inflammatory and repair response in the lung.

  1. HIF1α and HIF2α: sibling rivalry in hypoxic tumour growth and progression.

    Science.gov (United States)

    Keith, Brian; Johnson, Randall S; Simon, M Celeste

    2011-12-15

    Hypoxia-inducible factors (HIFs) are broadly expressed in human cancers, and HIF1α and HIF2α were previously suspected to promote tumour progression through largely overlapping functions. However, this relatively simple model has now been challenged in light of recent data from various approaches that reveal unique and sometimes opposing activities of these HIFα isoforms in both normal physiology and disease. These effects are mediated in part through the regulation of unique target genes, as well as through direct and indirect interactions with important oncoproteins and tumour suppressors, including MYC and p53. As HIF inhibitors are currently undergoing clinical evaluation as cancer therapeutics, a more thorough understanding of the unique roles performed by HIF1α and HIF2α in human neoplasia is warranted.

  2. CB2 cannabinoid receptors modulate HIF-1α and TIM-3 expression in a hypoxia-ischemia mouse model.

    Science.gov (United States)

    Kossatz, Elk; Maldonado, Rafael; Robledo, Patricia

    2016-12-01

    The role of CB2 cannabinoid receptors (CB 2 R) in global brain lesions induced by hypoxia-ischemia (HI) insult is still unresolved. The aim of this study was to evaluate the involvement of CB 2 R in the behavioural and biochemical underpinnings related to brain damage induced by HI in adult mice, and the mechanisms involved. CB 2 R knockout (KO) mice and wild-type littermates (WT) underwent permanent ligation of the left common carotid artery and hypoxia. Behavioural measurements in the rotarod, beam walking, object recognition, open field, and Irwin tests were carried out 24h, 72h and 7 days. In KO mice, more extensive brain injury was observed. Behavioural deficits in the Irwin test were observed in both genotypes; while WT mice showed progressive recovery by day 7, KO mice did not. Only KO mice showed alterations in motor learning, coordination and balance, and did not recover over time. A higher expression of microglia and astrocytes was observed in several brain areas of lesioned WT and KO mice. The possible alteration of the inflammatory-related factors HIF-1α and TIM-3 was evaluated in these animals. In both genotypes, HIF-1α and TIM-3 expression was observed in lesioned areas associated with activated microglia. However, the expression levels of these proteins were exacerbated in KO mice in several lesioned and non-lesioned brain structures. Our results indicate that CB 2 R may have a crucial neuroprotective role following HI insult through the modulation of the inflammatory-related HIF-1α/TIM-3 signalling pathway in microglia. Copyright © 2016 Elsevier B.V. and ECNP. All rights reserved.

  3. Hypoxia induces cancer-associated cAMP/PKA signalling through HIF-mediated transcriptional control of adenylyl cyclases VI and VII.

    Science.gov (United States)

    Simko, Veronika; Iuliano, Filippo; Sevcikova, Andrea; Labudova, Martina; Barathova, Monika; Radvak, Peter; Pastorekova, Silvia; Pastorek, Jaromir; Csaderova, Lucia

    2017-08-31

    Hypoxia is a phenomenon often arising in solid tumours, linked to aggressive malignancy, bad prognosis and resistance to therapy. Hypoxia-inducible factor-1 has been identified as a key mediator of cell and tissue adaptation to hypoxic conditions through transcriptional activation of many genes involved in glucose metabolism and other cancer-related processes, such as angiogenesis, cell survival and cell invasion. Cyclic adenosine 3'5'-monophosphate is one of the most ancient and evolutionarily conserved signalling molecules and the cAMP/PKA signalling pathway plays an important role in cellular adaptation to hypoxia. We have investigated possible new mechanisms behind hypoxic activation of the cAMP/PKA pathway. For the first time, we have shown that hypoxia induces transcriptional up-regulation of the system of adenylyl cyclases, enzymes responsible for cAMP production, in a panel of carcinoma cell lines of various origin. Our data prove functional relevance of the hypoxic increase of adenylyl cyclases VI and VII at least partially mediated by HIF-1 transcription factor. We have identified adenylyl cyclase VI and VII isoforms as mediators of cellular response to hypoxia, which led to the elevation of cAMP levels and enhanced PKA activity, with an impact on cell migration and pH regulation.

  4. Steroid receptor coactivator-3 regulates glucose metabolism in bladder cancer cells through coactivation of hypoxia inducible factor 1α.

    Science.gov (United States)

    Zhao, Wei; Chang, Cunjie; Cui, Yangyan; Zhao, Xiaozhi; Yang, Jun; Shen, Lan; Zhou, Ji; Hou, Zhibo; Zhang, Zhen; Ye, Changxiao; Hasenmayer, Donald; Perkins, Robert; Huang, Xiaojing; Yao, Xin; Yu, Like; Huang, Ruimin; Zhang, Dianzheng; Guo, Hongqian; Yan, Jun

    2014-04-18

    Cancer cell proliferation is a metabolically demanding process, requiring high glycolysis, which is known as "Warburg effect," to support anabolic growth. Steroid receptor coactivator-3 (SRC-3), a steroid receptor coactivator, is overexpressed and/or amplified in multiple cancer types, including non-steroid targeted cancers, such as urinary bladder cancer (UBC). However, whether SRC-3 regulates the metabolic reprogramming for cancer cell growth is unknown. Here, we reported that overexpression of SRC-3 accelerated UBC cell growth, accompanied by the increased expression of genes involved in glycolysis. Knockdown of SRC-3 reduced the UBC cell glycolytic rate under hypoxia, decreased tumor growth in nude mice, with reduction of proliferating cell nuclear antigen and lactate dehydrogenase expression levels. We further revealed that SRC-3 could interact with hypoxia inducible factor 1α (HIF1α), which is a key transcription factor required for glycolysis, and coactivate its transcriptional activity. SRC-3 was recruited to the promoters of HIF1α-target genes, such as glut1 and pgk1. The positive correlation of expression levels between SRC-3 and Glut1 proteins was demonstrated in human UBC patient samples. Inhibition of glycolysis through targeting HK2 or LDHA decelerated SRC-3 overexpression-induced cell growth. In summary, overexpression of SRC-3 promoted glycolysis in bladder cancer cells through HIF1α to facilitate tumorigenesis, which may be an intriguing drug target for bladder cancer therapy.

  5. Hypoxia in Tumor Angiogenesis and Metastasis: Evaluation of VEGF and MMP Over-expression and Down-Regulation of HIF-1alpha with RNAi in Hypoxic Tumor Cells

    Science.gov (United States)

    Shah, Shruti

    Background: As tumor mass grows beyond a few millimeters in diameter, the angiogenic "switch" is turned on leading to recruitment of blood vessels from surrounding artery and veins. However, the tumor mass is poorly perfused and there are pockets of hypoxia or lower oxygen concentrations relative to normal tissue. Hypoxia-inducing factor-1a (HIF-1a), a transcription factor, is activated when the oxygen concentration is low. Upon activation of HIF-1a, a number of other genes also turn on that allows the tumor to become more aggressive and resistant to therapy. Purpose: The main objectives of this study were to evaluate the effect of hypoxia-induced HIF-1a followed by over-expression of angiogenic and metastatic markers in tumor cells and down-regulation of HIF-1a using nanoparticle-delivered RNA interference therapy. Methods: Human ovarian (SKOV3) and breast (MDA-MB-231) adenocarcinoma cells were incubated under normoxic and hypoxic conditions. Following hypoxia treatment of the cells, HIF-1α, vascular endothelial growth factor (VEGF), matrix metalloproteinase 2 (MMP-2), and MMP-9 expression was analyzed qualitatively and quantitatively. For intracellular delivery of HIF-1a gene silencing small interfering RNA (siRNA), type B gelatin nanoparticles were fabricated using the solvent displacement method and the surface was modified with poly(ethylene glycol) (PEG, Mol. wt. 2kDa). Cellular uptake and distribution of the nanoparticles was observed with Cy3-siRNA loaded, FITC-conjugated gelatin nanoparticles. Cytotoxicity of the nanoparticle formulations was evaluated in both the cell lines. siRNA was transfected in the gelatin nanoparticles under hypoxic conditions. Total cellular protein and RNA were extracted for analysis of HIF1a, VEGF, MMP-2 and MMP-9 expression. Results: MDA-MB-231 and SKOV3 cells show increased expression of HIF1a under hypoxic conditions compared to baseline levels at normoxic conditions. ELISA and western blots of VEGF, MMP-2 and MMP-9 appear to

  6. Emerging roles of hypoxia-inducible factors and reactive oxygen species in cancer and pluripotent stem cells

    Directory of Open Access Journals (Sweden)

    Shigeo Saito

    2015-06-01

    Full Text Available Eukaryotic organisms require oxygen homeostasis to maintain proper cellular function for survival. During conditions of low oxygen tension (hypoxia, cells activate the transcription of genes that induce an adaptive response, which supplies oxygen to tissues. Hypoxia and hypoxia-inducible factors (HIFs may contribute to the maintenance of putative cancer stem cells, which can continue self-renewal indefinitely and express stemness genes in hypoxic stress environments (stem cell niches. Reactive oxygen species (ROS have long been recognized as toxic by-products of aerobic metabolism that are harmful to living cells, leading to DNA damage, senescence, or cell death. HIFs may promote a cancer stem cell state, whereas the loss of HIFs induces the production of cellular ROS and activation of proteins p53 and p16Ink4a, which lead to tumor cell death and senescence. ROS seem to inhibit HIF regulation in cancer cells. By contrast, controversial data have suggested that hypoxia increases the generation of ROS, which prevents hydroxylation of HIF proteins by inducing their transcription as negative feedback. Moreover, hypoxic conditions enhance the generation of induced pluripotent stem cells (iPSCs. During reprogramming of somatic cells into a PSC state, cells attain a metabolic state typically observed in embryonic stem cells (ESCs. ESCs and iPSCs share similar bioenergetic metabolisms, including decreased mitochondrial number and activity, and induced anaerobic glycolysis. This review discusses the current knowledge regarding the emerging roles of ROS homeostasis in cellular reprogramming and the implications of hypoxic regulation in cancer development.

  7. Roles of p300 and cyclic adenosine monophosphate response element binding protein in high glucose-induced hypoxia-inducible factor 1α inactivation under hypoxic conditions.

    Science.gov (United States)

    Ding, Lingtao; Yang, Minlie; Zhao, Tianlan; Lv, Guozhong

    2017-05-01

    Given the high prevalence of diabetes and burn injuries worldwide, it is essential to dissect the underlying mechanism of delayed burn wound healing in diabetes patients, especially the high glucose-induced hypoxia-inducible factor 1 (HIF-1)-mediated transcription defects. Human umbilical vein endothelial cells were cultured with low or high concentrations of glucose. HIF-1α-induced vascular endothelial growth factor (VEGF) transcription was measured by luciferase assay. Immunofluorescence staining was carried out to visualize cyclic adenosine monophosphate response element binding protein (CREB) localization. Immunoprecipitation was carried out to characterize the association between HIF-1α/p300/CREB. To test whether p300, CREB or p300+CREB co-overexpression was sufficient to rescue the HIF-1-mediated transcription defect after high glucose exposure, p300, CREB or p300+CREB co-overexpression were engineered, and VEGF expression was quantified. Finally, in vitro angiogenesis assay was carried out to test whether the high glucose-induced angiogenesis defect is rescuable by p300 and CREB co-overexpression. Chronic high glucose treatment resulted in impaired HIF-1-induced VEGF transcription and CREB exclusion from the nucleus. P300 or CREB overexpression alone cannot rescue high glucose-induced HIF-1α transcription defects. In contrast, co-overexpression of p300 and CREB dramatically ameliorated high glucose-induced impairment of HIF-1-mediated VEGF transcription, as well as in vitro angiogenesis. Finally, we showed that co-overexpression of p300 and CREB rectifies the dissociation of HIF-1α-p300-CREB protein complex in chronic high glucose-treated cells. Both p300 and CREB are required for the function integrity of HIF-1α transcription machinery and subsequent angiogenesis, suggesting future studies to improve burn wound healing might be directed to optimization of the interaction between p300, CREB and HIF-1α. © 2016 The Authors. Journal of Diabetes

  8. Silencing of reversion-inducing cysteine-rich protein with Kazal motifs stimulates hyperplastic phenotypes through activation of epidermal growth factor receptor and hypoxia-inducible factor-2α.

    Directory of Open Access Journals (Sweden)

    You Mie Lee

    Full Text Available Reversion-inducing cysteine-rich protein with Kazal motifs (RECK, a tumor suppressor is down-regulated by the oncogenic signals and hypoxia, but the biological function of RECK in early tumorigenic hyperplastic phenotypes is largely unknown. Knockdown of RECK by small interfering RNA (siRECK or hypoxia significantly promoted cell proliferation in various normal epithelial cells. Hypoxia as well as knockdown of RECK by siRNA increased the cell cycle progression, the levels of cyclin D1 and c-Myc, and the phosphorylation of Rb protein (p-pRb, but decreased the expression of p21(cip1, p27(kip1, and p16(ink4A. HIF-2α was upregulated by knockdown of RECK, indicating HIF-2α is a downstream target of RECK. As knockdown of RECK induced the activation of epidermal growth factor receptor (EGFR and treatment of an EGFR kinase inhibitor, gefitinib, suppressed HIF-2α expression induced by the silencing of RECK, we can suggest that the RECK silenicng-EGFR-HIF-2α axis might be a key molecular mechanism to induce hyperplastic phenotype of epithelial cells. It was also found that shRNA of RECK induced larger and more numerous colonies than control cells in an anchorage-independent colony formation assay. Using a xenograft assay, epithelial cells with stably transfected with shRNA of RECK formed a solid mass earlier and larger than those with control cells in nude mice. In conclusion, the suppression of RECK may promote the development of early tumorigenic hyperplastic characteristics in hypoxic stress.

  9. Relationship between serum hypoxia-inducible factor-1α and carotid plaque in patients with type 2 diabetes mellitus

    International Nuclear Information System (INIS)

    E Weiqin; Shi Bimin

    2012-01-01

    Objective: To observe the changes of type 2 diabetes mellitus (T2DM) patients' serum hypoxia inducible factor-1α (HIF-1α), and evaluate the relationship between serum HIF-1α and vascular lesions of atherosclerosis. Methods: The serum level of HIF-1α in 32 T2DM with carotid plaques (T2DM+CP group), 24 T2DM without macrovascular complications (T2DM group), and 24 controls was studied with ELISA method. Results: The serum HIF-1α level in T2DM with and without carotid plaque group was significantly higher than that in the controls (all P<0.01). Furthermore, among T2DM, the level of HIF-1α was higher in patients with carotid plaque than that without carotid plaque (P<0.05) . The serum HIF-1α was positively correlated with fasting plasma glucose, HbAlc and HOMA-IR (all P<0.05). Multiple linear stepwise regression analysis showed that HbAlc was the independent determinants of HIF-1α. Conclusion: High level of serum HIF-1α in T2DM patients concerns with blood glucose and insulin resistance, which plays an important role in the development of macrovascular complications. (authors)

  10. The expression of vascular endothelial growth factor is affected by hypoxia inducible factor-1α in peritoneum of endometriosis mice treated with genistein

    Directory of Open Access Journals (Sweden)

    Sylvi Wafda Nur Amellia

    2016-09-01

    Full Text Available This study aimed to investigate whether the genistein is able to decrease the expressions of vascular endothelial growth factor-A (VEGF-A and hypoxia inducible factor-1α (HIF-1α in mouse model of endometriosis. Forty female mice (Mus musculus were divided into eight groups (n = 5 each, including the control (untreated group, endometriosis group, and endometriosis groups treated with various doses of genistein (50; 100; 200; 300; 400; and 500 mg/day. VEGF-A and HIF-1α analyses were performed by immunohistochemistry. We found significant increases in the VEGF-A and HIF-α expressions in endometriosis group compared to the control group. The increased expressions of VEGF-A and HIF-1α were significantly (p < 0.05 attenuated by the administration of all doses of genistein. In conclusion, in mouse model of endometriosis, genistein potentially inhibits the increase in angiogenesis in peritoneal tissue. Therefore, this result may provide a novel anti-angiogenic treatment strategy for the therapy of endometriosis.

  11. cAMP-response Element-binding Protein (CREB) and NF-κB Transcription Factors Are Activated during Prolonged Hypoxia and Cooperatively Regulate the Induction of Matrix Metalloproteinase MMP1*

    Science.gov (United States)

    Nakayama, Koh

    2013-01-01

    Responses to low levels of oxygen (hypoxia) are essential to maintain homeostasis. During the hypoxic response, gene expression is altered by various transcription factors. The transcription factor, hypoxia-inducible factor (HIF), plays a central role in the hypoxic response. The α subunit of HIF, which is actively degraded during normoxia, becomes stabilized during hypoxia, which leads to HIF activation. A microarray analysis of HeLa cells showed that expression of matrix metalloproteinase 1 (MMP1) was markedly induced during prolonged hypoxia. CREB and NF-κB binding sites were identified in the MMP1 promoter region between 1945 and 1896 nucleotides upstream of the transcription start site. Assays with luciferase reporters demonstrated that HIF activity was induced during the early phase of hypoxia, whereas CREB and NF-κB were activated during the later (prolonged) phase. Depletion of CREB and/or NF-κB reduced MMP1 induction during prolonged hypoxia both at the mRNA and protein levels. A chromatin immunoprecipitation assay demonstrated binding of CREB and NF-κB to the MMP1 promoter. Finally, cell migration and invasion on a collagen matrix and pulmonary metastasis in nude mice were inhibited after depletion of CREB and NF-κB in MDA-MB-231 cells. Taken together, these results suggest that the cooperative action of CREB and NF-κB plays an important role to induce MMP1 expression during prolonged hypoxia and regulates cell migration and invasion in cancer cells. PMID:23775082

  12. Inhibition of hypoxia inducible factor-1alpha by dihydroxyphenylethanol, a product from olive oil, blocks microsomal prostaglandin-E synthase-1/vascular endothelial growth factor expression and reduces tumor angiogenesis.

    Science.gov (United States)

    Terzuoli, Erika; Donnini, Sandra; Giachetti, Antonio; Iñiguez, Miguel A; Fresno, Manuel; Melillo, Giovanni; Ziche, Marina

    2010-08-15

    2-(3,4-dihydroxyphenil)-ethanol (DPE), a polyphenol present in olive oil, has been found to attenuate the growth of colon cancer cells, an effect presumably related to its anti-inflammatory activity. To further explore the effects of DPE on angiogenesis and tumor growth we investigated the in vivo efficacy of DPE in a HT-29 xenograft model and in vitro activities in colon cancer cells exposed to interleukin-1beta (IL-1beta) and prostaglandin E-2 (PGE-2). DPE (10 mg/kg/day for 14 days) inhibited tumor growth, reducing vessel lumina and blood perfusion to tumor, and diminished expression of hypoxia inducible factor-1alpha (HIF-1alpha), vascular endothelial growth factor (VEGF), and microsomal prostaglandin-E synthase-1 (mPGEs-1). In vitro, DPE (100 mumol/L) neither affected cell proliferation nor induced apoptosis in HT-29 and WiDr cells. DPE prevented the IL-1beta-mediated increase of mPGEs-1 expression and PGE-2 generation, as it did the silencing of HIF-1alpha. Moreover, DPE blocked mPGEs-1-dependent expression of VEGF and inhibited endothelial sprouting induced by tumor cells in a coculture system. PGE-2 triggers a feed-forward loop involving HIF-1alpha, which impinges on mPGEs-1 and VEGF expression, events prevented by DPE via extracellular signal-related kinase 1/2. The reduction of PGE-2 and VEGF levels, caused by DPE, was invariably associated with a marked decrease in HIF-1alpha expression and activity, independent of proteasome activity, indicating that the DPE effects on tumor growth and angiogenesis are dependent on the inhibition of HIF-1alpha translation. We show that the in vivo DPE antitumor effect is associated with anti-inflammatory and antiangiogenic activities resulting from the downregulation of the HIF-1alpha/mPGEs-1/VEGF axis.

  13. Leukemia kidney infiltration can cause secondary polycythemia by activating hypoxia-inducible factor (HIF) pathway.

    Science.gov (United States)

    Osumi, Tomoo; Awazu, Midori; Fujimura, Eriko; Yamazaki, Fumito; Hashiguchi, Akinori; Shimada, Hiroyuki

    2013-06-01

    Secondary polycythemia with increased production of erythropoietin (EPO) is known to occur in kidney diseases such as hydronephrosis and cystic disease, but the mechanism remains unclear. We report an 18-year-old female with isolated renal relapse of acute lymphoblastic leukemia accompanied by polycythemia. At the relapse, she presented with bilateral nephromegaly, mild renal dysfunction, and erythrocytosis with increased serum EPO levels up to 52.1 mIU/mL (9.1-32.8). Renal biopsy demonstrated diffuse lymphoblastic infiltration. The expression of hypoxia-inducible factor (HIF)-1α, which is undetectable in normal kidney, was observed in the renal tubule epithelium compressed by lymphoblastic cells. These findings suggest that erythrocytosis was caused by renal ischemia due to leukemic infiltration. Polycythemia probably became apparent because of the lack of leukemic involvement of the bone marrow. With chemotherapy, the serum EPO level rapidly decreased to normal range accompanied by the normalization of kidney size and function. Renal leukemic infiltration may enhance EPO production, although not recognized in the majority of cases because of bone marrow involvement. Our case has clarified the mechanism of previously reported polycythemia associated with renal diseases as renal ischemia. Furthermore, we have added renal ischemia resulting from tumor infiltration to the list of causes of secondary polycythemia.

  14. Platelet lysate activates quiescent cell proliferation and reprogramming in human articular cartilage: Involvement of hypoxia inducible factor 1.

    Science.gov (United States)

    Nguyen, Van Thi; Cancedda, Ranieri; Descalzi, Fiorella

    2018-03-01

    The idea of rescuing the body self-repair capability lost during evolution is progressively gaining ground in regenerative medicine. In particular, growth factors and bioactive molecules derived from activated platelets emerged as promising therapeutic agents acting as trigger for repair of tissue lesions and restoration of tissue functions. Aim of this study was to assess the potential of a platelet lysate (PL) for human articular cartilage repair considering its activity on progenitor cells and differentiated chondrocytes. PL induced the re-entry in the cell cycle of confluent, growth-arrested dedifferentiated/progenitor cartilage cells. In a cartilage permissive culture environment, differentiated cells also resumed proliferation after exposure to PL. These findings correlated with an up-regulation of the proliferation/survival pathways ERKs and Akt and with an induction of cyclin D1. In short- and long-term cultures of articular cartilage explants, we observed a release of proliferating chondroprogenitors able to differentiate and form an "in vitro" tissue with properties of healthy articular cartilage. Moreover, in cultured cartilage cells, PL induced a hypoxia-inducible factor (HIF-1) alpha increase, its nuclear relocation and the binding to HIF-1 responsive elements. These events were possibly related to the cell proliferation because the HIF-1 inhibitor acriflavine inhibited HIF-1 binding to HIF-1 responsive elements and cell proliferation. Our study demonstrates that PL induces quiescent cartilage cell activation and proliferation leading to new cartilage formation, identifies PL activated pathways playing a role in these processes, and provides a rationale to the application of PL for therapeutic treatment of damaged articular cartilage. Copyright © 2017 John Wiley & Sons, Ltd.

  15. The Role of Hypoxia-Inducible Factor-1α, Glucose Transporter-1, (GLUT-1 and Carbon Anhydrase IX in Endometrial Cancer Patients

    Directory of Open Access Journals (Sweden)

    Pawel Sadlecki

    2014-01-01

    Full Text Available Hypoxia-inducible factor-1α (HIF-1α, glucose transporter-1 (GLUT-1, and carbon anhydrase IX (CAIX are important molecules that allow adaptation to hypoxic environments. The aim of our study was to investigate the correlation between HIF-1α, GLUT-1, and CAIX protein level with the clinicopathological features of endometrial cancer patients. Materials and Methods. 92 endometrial cancer patients, aged 37–84, were enrolled to our study. In all patients clinical stage, histologic grade, myometrial invasion, lymph node, and distant metastases were determined. Moreover, the survival time was assessed. Immunohistochemical analyses were performed on archive formalin fixed paraffin embedded tissue sections. Results. High significant differences (P=0.0115 were reported between HIF-1α expression and the histologic subtype of cancer. Higher HIF-1α expression was associated with the higher risk of recurrence (P=0.0434. The results of GLUT-1 and CAIX expression did not reveal any significant differences between the proteins expression in the primary tumor and the clinicopathological features. Conclusion. The important role of HIF-1α in the group of patients with the high risk of recurrence and the negative histologic subtype of the tumor suggest that the expression of this factor might be useful in the panel of accessory pathomorphological tests and could be helpful in establishing more accurate prognosis in endometrial cancer patients.

  16. Correlation of Hypoxia-Inducible Factor 1α with Angiogenesis in Liver Tumors After Transcatheter Arterial Embolization in an Animal Model

    International Nuclear Information System (INIS)

    Liang Bin; Zheng Chuansheng; Feng, Gan-Sheng; Wu Hanping; Wang Yong; Zhao Hui; Qian Jun; Liang Huimin

    2010-01-01

    This study sought to determine the expression of hypoxia-inducible factor 1α (HIF-1α) and its relation to angiogenesis in liver tumors after transcatheter arterial embolization (TAE) in an animal model. A total of 20 New Zealand White rabbits were implanted with VX2 tumor in liver. TAE-treated group animals (n = 10) received TAE with polyvinyl alcohol particles. Control group animals (n = 10) received sham embolization with distilled water. Six hours or 3 days after TAE, animals were humanely killed, and tumor samples were collected. Immunohistochemical staining was performed to evaluate HIF-1α and vascular endothelial growth factor (VEGF) protein expression and microvessel density (MVD). Real-time polymerase chain reaction was performed to examine VEGF mRNA levels. The levels of HIF-1α protein were significantly higher in TAE-treated tumors than those in the control tumors (P = 0.001). HIF-1α protein was expressed in viable tumor cells that were located predominantly at the periphery of necrotic tumor regions. The levels of VEGF protein and mRNA, and mean MVD were significantly increased in TAE-treated tumors compared with the control tumors (P = 0.001, 0.000, and 0.001, respectively). HIF-1α protein level was significantly correlated with VEGF mRNA (r = 0.612, P = 0.004) and protein (r = 0.554, P = 0.011), and MVD (r = 0.683, P = 0.001). We conclude that HIF-1α is overexpressed in VX2 tumors treated with TAE as a result of intratumoral hypoxia generated by the procedure and involved in activation of the TAE-associated tumor angiogenesis. HIF-1α might represent a promising therapeutic target for antiangiogenesis in combination with TAE against liver tumors.

  17. HIF-1 Alpha and Placental Growth Factor in Pregnancies Complicated With Preeclampsia: A Qualitative and Quantitative Analysis.

    Science.gov (United States)

    Rath, Gayatri; Aggarwal, Ruby; Jawanjal, Poonam; Tripathi, Richa; Batra, Aruna

    2016-01-01

    The pathophysiology of preeclampsia is not clearly understood worldwide. Hypoxia inducible factor 1α (HIF-1α) is thought to be the preliminary factor for the hypoxic conditions prevailing in preeclampsia, which causes imbalance in the expression of angiogenic proteins. A proangiogenic protein, placental growth factor (PIGF), is reported to be dysregulated in preeclampsia. Therefore, this study focuses on the investigation of HIF-1α and PIGF in preeclamptic conditions and a possible molecular association between them. Placental tissue (n = 45 + 45) and serum samples (n = 80 + 80) of preeclamptic patients and healthy control were collected and processed for the analysis of HIF-1α and PIGF by immunohistochemistry and enzyme-linked immunosorbent assay (ELISA). In preeclamptic group, the significant nuclear and cytoplasmic expression of HIF-1α was noticed in syncytiotrophoblast (P = 0.0001) but in control placenta, it was localized to cytoplasm (P = 0.0001). The intensity of PIGF expression was lower in syncytiotrophoblast cytoplasm (P = 0.0001) in preeclamptic cases as compared with control. Also, the significant upregulated concentration of HIF-1α and downregulated PIGF was observed in serum samples of preeclamptic woman (P = 0.0001). Thus, there was a significant direct negative correlation between HIF-1α and PIGF both at tissue and serum level (P preeclampsia. © 2014 Wiley Periodicals, Inc.

  18. Combination of HIF-1α gene transfection and HIF-1-activated bone marrow-derived angiogenic cell infusion improves burn wound healing in aged mice.

    Science.gov (United States)

    Du, J; Liu, L; Lay, F; Wang, Q; Dou, C; Zhang, X; Hosseini, S M; Simon, A; Rees, D J; Ahmed, A K; Sebastian, R; Sarkar, K; Milner, S; Marti, G P; Semenza, G L; Harmon, J W

    2013-11-01

    Impaired burn wound healing in the elderly represents a major clinical problem. Hypoxia-inducible factor-1 (HIF-1) is a transcriptional activator that orchestrates the cellular response to hypoxia. Its actions in dermal wounds promote angiogenesis and improve healing. In a murine burn wound model, aged mice had impaired wound healing associated with reduced levels of HIF-1. When gene therapy with HIF-1 alone did not correct these deficits, we explored the potential benefit of HIF-1 gene therapy combined with the intravenous infusion of bone marrow-derived angiogenic cells (BMDACs) cultured with dimethyloxalylglycine (DMOG). DMOG is known to reduce oxidative degradation of HIF-1. The mice treated with a plasmid DNA construct expressing a stabilized mutant form of HIF-1α (CA5-HIF-1α)+BMDACs had more rapid wound closure. By day 17, there were more mice with completely closed wounds in the treated group (χ(2), P=0.05). The dermal blood flow measured by laser Doppler showed significantly increased wound perfusion on day 11. Homing of BMDACs to the burn wound was dramatically enhanced by CA5-HIF-1α gene therapy. HIF-1α mRNA expression in the burn wound was increased after transfection with CA5-HIF-1α plasmid. Our findings offer insight into the pathophysiology of burns in the elderly and point to potential targets for developing new therapeutic strategies.

  19. Reactive oxygen species-driven HIF1α triggers accelerated glycolysis in endothelial cells exposed to low oxygen tension

    International Nuclear Information System (INIS)

    Paik, Jin-Young; Jung, Kyung-Ho; Lee, Jin-Hee; Park, Jin-Won; Lee, Kyung-Han

    2017-01-01

    Endothelial cells and their metabolic state regulate glucose transport into underlying tissues. Here, we show that low oxygen tension stimulates human umbilical vein endothelial cell 18 F–fluorodeoxyglucose ( 18 F–FDG) uptake and lactate production. This was accompanied by augmented hexokinase activity and membrane Glut-1, and increased accumulation of hypoxia-inducible factor-1α (HIF1α). Restoration of oxygen reversed the metabolic effect, but this was blocked by HIF1α stabilization. Hypoxia-stimulated 18 F–FDG uptake was completely abrogated by silencing of HIF1α expression or by a specific inhibitor. There was a rapid and marked increase of reactive oxygen species (ROS) by hypoxia, and ROS scavenging or NADPH oxidase inhibition completely abolished hypoxia-stimulated HIF1α and 18 F–FDG accumulation, placing ROS production upstream of HIF1α signaling. Hypoxia-stimulated HIF1α and 18 F–FDG accumulation was blocked by the protein kinase C (PKC) inhibitor, staurosporine. The phosphatidylinositol 3-kinase (PI3K) inhibitor, wortmannin, blocked hypoxia-stimulated 18 F–FDG uptake and attenuated hypoxia-responsive element binding of HIF1α without influencing its accumulation. Thus, ROS-driven HIF1α accumulation, along with PKC and PI3K signaling, play a key role in triggering accelerated glycolysis in endothelial cells under hypoxia, thereby contributing to 18 F–FDG transport.

  20. Transplantation of Rat Mesenchymal Stem Cells Overexpressing Hypoxia-Inducible Factor 2α Improves Blood Perfusion and Arteriogenesis in a Rat Hindlimb Ischemia Model

    Directory of Open Access Journals (Sweden)

    Weifeng Lu

    2017-01-01

    Full Text Available Mesenchymal stem cells (MSCs have been increasingly tested in cell-based therapy to treat numerous diseases. Genetic modification to improve MSC behavior may enhance posttransplantation outcome. This study aims to test the potential therapeutic benefits of rat bone marrow MSCs overexpressing hypoxia-inducible factor 2α (rMSCsHIF-2α in a rat hindlimb ischemia model. PBS, rMSCs, or rMSCsHIF-2α were injected into rat ischemic hindlimb. Compared with the injection of PBS or rMSCs, transplantation of rMSCsHIF-2α significantly improved blood perfusion, increased the number of vessel branches in the muscle of the ischemic hindlimb, and improved the foot mobility of the ischemic hindlimb (all P<0.05. rMSCHIF-2α transplantation also markedly increased the expression of proangiogenic factors VEGF, bFGF, and SDF1 and Notch signaling proteins including DII4, NICD, Hey1, and Hes1, whereas it reduced the expression of proapoptotic factor Bax in the muscle of the ischemic hindlimb. Overexpression of HIF-2α did not affect rMSC stemness and proliferation under normoxia but significantly increased rMSC migration and tube formation in matrigel under hypoxia (all P<0.05. RMSCsHIF-2α stimulated endothelial cell invasion under hypoxia significantly (P<0.05. Genetic modification of rMSCs via overexpression of HIF-2α improves posttransplantation outcomes in a rat hindlimb ischemia model possibly by stimulating proangiogenic growth factors and cytokines.

  1. HIF-1α Deletion in the Endothelium, but Not in the Epithelium, Protects From Radiation-Induced Enteritis

    Directory of Open Access Journals (Sweden)

    Aurore Toullec

    2018-01-01

    Conclusions: We demonstrate in vivo that HIF-1α impacts radiation-induced enteritis and that this role differs according to the targeted cell type. Our work provides a new role for HIF-1α and endothelium-dependent mechanisms driving inflammatory processes in gut mucosae. Results presented show that effects on normal tissues have to be taken into account in approaches aiming to modulate hypoxia or hypoxia-related molecular mechanisms.

  2. The novel hypoxic cytotoxin, TX-2098 has antitumor effect in pancreatic cancer; possible mechanism through inhibiting VEGF and hypoxia inducible factor-1α targeted gene expression.

    Science.gov (United States)

    Miyake, Kotaro; Nishioka, Masanori; Imura, Satoru; Batmunkh, Erdenebulgan; Uto, Yoshihiro; Nagasawa, Hideko; Hori, Hitoshi; Shimada, Mitsuo

    2012-08-01

    Tumor hypoxia has been considered to be a potential therapeutic target, because hypoxia is a common feature of solid tumors and is associated with their malignant phenotype. In the present study, we investigated the antitumor effect of a novel hypoxic cytotoxin, 3-[2-hydroxyethyl(methyl)amino]-2-quinoxalinecarbonitrile 1,4-dioxide (TX-2098) in inhibiting the expression of hypoxia inducible factor-1α (HIF-1α), and consequently vascular endothelial cell growth factor (VEGF) expression in pancreatic cancer. The antitumor effects of TX-2098 under hypoxia were tested against various human pancreatic cancer cell lines using WST-8 assay. VEGF protein induced pancreatic cancer was determined on cell-free supernatant by ELISA. Moreover, nude mice bearing subcutaneously (s.c.) or orthotopically implanted human SUIT-2 were treated with TX-2098. Tumor volume, survival and expression of HIF-1 and associated molecules were evaluated in treatment versus control groups. In vitro, TX-2098 inhibited the proliferation of various pancreatic cancer cell lines. In s.c model, tumors from nude mice injected with pancreatic cancer cells and treated with TX-2098 showed significant reductions in volume (P<0.01 versus control). Quantitative real-time reverse transcription-PCR analysis revealed that TX-2098 significantly inhibited mRNA expression of the HIF-1 associated molecules, VEGF, glucose transporter 1 and Aldolase A (P<0.01 versus control). These treatments also prolong the survival in orthotopic models. These results suggest that the effect of TX-2098 in pancreatic cancer might be correlated with the expression of VEGF and HIF-1 targeted molecules. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Myeloid HIF-1 is protective in Helicobacter pylori-mediated gastritis.

    Science.gov (United States)

    Matak, Pavle; Heinis, Mylène; Mathieu, Jacques R R; Corriden, Ross; Cuvellier, Sylvain; Delga, Stéphanie; Mounier, Rémi; Rouquette, Alexandre; Raymond, Josette; Lamarque, Dominique; Emile, Jean-François; Nizet, Victor; Touati, Eliette; Peyssonnaux, Carole

    2015-04-01

    Helicobacter pylori infection triggers chronic inflammation of the gastric mucosa that may progress to gastric cancer. The hypoxia-inducible factors (HIFs) are the central mediators of cellular adaptation to low oxygen levels (hypoxia), but they have emerged recently as major transcriptional regulators of immunity and inflammation. No studies have investigated whether H. pylori affects HIF signaling in immune cells and a potential role for HIF in H. pylori-mediated gastritis. HIF-1 and HIF-2 expression was examined in human H. pylori-positive gastritis biopsies. Subsequent experiments were performed in naive and polarized bone marrow-derived macrophages from wild-type (WT) and myeloid HIF-1α-null mice (HIF-1(Δmyel)). WT and HIF-1(Δmyel) mice were inoculated with H. pylori by oral gavage and sacrificed 6 mo postinfection. HIF-1 was specifically expressed in macrophages of human H. pylori-positive gastritis biopsies. Macrophage HIF-1 strongly contributed to the induction of proinflammatory genes (IL-6, IL-1β) and inducible NO synthase in response to H. pylori. HIF-2 expression and markers of M2 macrophage differentiation were decreased in response to H. pylori. HIF-1(Δmyel) mice inoculated with H. pylori for 6 mo presented with a similar bacterial colonization than WT mice but, surprisingly, a global increase of inflammation, leading to a worsening of the gastritis, measured by an increased epithelial cell proliferation. In conclusion, myeloid HIF-1 is protective in H. pylori-mediated gastritis, pointing to the complex counterbalancing roles of innate immune and inflammatory phenotypes in driving this pathology. Copyright © 2015 by The American Association of Immunologists, Inc.

  4. Yak response to high-altitude hypoxic stress by altering mRNA expression and DNA methylation of hypoxia-inducible factors.

    Science.gov (United States)

    Xiong, Xianrong; Fu, Mei; Lan, Daoliang; Li, Jian; Zi, Xiangdong; Zhong, Jincheng

    2015-01-01

    Hypoxia-inducible factors (HIFs) are oxygen-dependent transcriptional activators, which play crucial roles in tumor angiogenesis and mammalian development, and regulate the transcription of genes involved in oxygen homeostasis in response to hypoxia. However, information on HIF-1α and HIF-2α in yak (Bos grunniens) is scarce. The complete coding region of yak HIF-2α was cloned, its mRNA expression in several tissues were determined, and the expression levels were compared with those of closely related low-altitude cattle (Bos taurus), and the methylation status of promoter regions were analyzed to better understand the roles of HIF-1α and HIF-2α in domesticated yak. The yak HIF-2α cDNA was cloned and sequenced in the present work reveals the evolutionary conservation through multiple sequence alignment, although 15 bases changed, resulting in 8 amino acid substitutions in the translated proteins in cattle. The tissue-specific expression results showed that HIF-1α is ubiquitously expressed, whereas HIF-2α expression is limited to endothelial tissues (kidney, heart, lung, spleen, and liver) and blood in yak. Both HIF-1α and HIF-2α expressions were higher in yak tissues than in cattle. The HIF-1α expression level is much higher in yak than cattle in these organs, except for the lung (P hypoxic stress response mechanism and may assist current medical research to understand hypoxia-related diseases.

  5. Coumestrol suppresses hypoxia inducible factor 1α by inhibiting ROS mediated sphingosine kinase 1 in hypoxic PC-3 prostate cancer cells.

    Science.gov (United States)

    Cho, Sung-Yun; Cho, Sunmi; Park, Eunkyung; Kim, Bonglee; Sohn, Eun Jung; Oh, Bumsuk; Lee, Eun-Ok; Lee, Hyo-Jeong; Kim, Sung-Hoon

    2014-06-01

    Among many signals to regulate hypoxia inducible factor 1α (HIF-1α), sphingosine kinase 1 (SPHK1) is also involved in various biological activities such as cell growth, survival, invasion, angiogenesis, and carcinogenesis. Thus, in the present study, molecular mechanisms of coumestrol were investigated on the SPHK1 and HIF-1α signaling pathway in hypoxic PC-3 prostate cancer cells. Coumestrol significantly suppressed SPHK1 activity and accumulation of HIF-1α in a time- and concentration-dependent manner in hypoxic PC-3 cells. In addition, coumestrol inhibited the phosphorylation status of AKT and glycogen synthase kinase-3β (GSK 3β) signaling involved in cancer metabolism. Furthermore, SPHK1 siRNA transfection, sphigosine kinase inhibitor (SKI), reactive oxygen species (ROS) enhanced the inhibitory effect of coumestrol on the accumulation of HIF-1α and the expression of pAKT and pGSK 3β in hypoxic PC-3 cells by combination index. Overall, our findings suggest that coumestrol suppresses the accumulation of HIF-1α via suppression of SPHK1 pathway in hypoxic PC-3 cells. Copyright © 2014. Published by Elsevier Ltd.

  6. Hif-1α and Hif-2α synergize to suppress AML development but are dispensable for disease maintenance.

    Science.gov (United States)

    Vukovic, Milica; Guitart, Amelie V; Sepulveda, Catarina; Villacreces, Arnaud; O'Duibhir, Eoghan; Panagopoulou, Theano I; Ivens, Alasdair; Menendez-Gonzalez, Juan; Iglesias, Juan Manuel; Allen, Lewis; Glykofrydis, Fokion; Subramani, Chithra; Armesilla-Diaz, Alejandro; Post, Annemarie E M; Schaak, Katrin; Gezer, Deniz; So, Chi Wai Eric; Holyoake, Tessa L; Wood, Andrew; O'Carroll, Dónal; Ratcliffe, Peter J; Kranc, Kamil R

    2015-12-14

    Leukemogenesis occurs under hypoxic conditions within the bone marrow (BM). Knockdown of key mediators of cellular responses to hypoxia with shRNA, namely hypoxia-inducible factor-1α (HIF-1α) or HIF-2α, in human acute myeloid leukemia (AML) samples results in their apoptosis and inability to engraft, implicating HIF-1α or HIF-2α as therapeutic targets. However, genetic deletion of Hif-1α has no effect on mouse AML maintenance and may accelerate disease development. Here, we report the impact of conditional genetic deletion of Hif-2α or both Hif-1α and Hif-2α at different stages of leukemogenesis in mice. Deletion of Hif-2α accelerates development of leukemic stem cells (LSCs) and shortens AML latency initiated by Mll-AF9 and its downstream effectors Meis1 and Hoxa9. Notably, the accelerated initiation of AML caused by Hif-2α deletion is further potentiated by Hif-1α codeletion. However, established LSCs lacking Hif-2α or both Hif-1α and Hif-2α propagate AML with the same latency as wild-type LSCs. Furthermore, pharmacological inhibition of the HIF pathway or HIF-2α knockout using the lentiviral CRISPR-Cas9 system in human established leukemic cells with MLL-AF9 translocation have no impact on their functions. We therefore conclude that although Hif-1α and Hif-2α synergize to suppress the development of AML, they are not required for LSC maintenance. © 2015 Vukovic et al.

  7. Sphingosine kinase-1 is a hypoxia-regulated gene that stimulates migration of human endothelial cells

    International Nuclear Information System (INIS)

    Schwalm, Stephanie; Doell, Frauke; Roemer, Isolde; Bubnova, Svetlana; Pfeilschifter, Josef; Huwiler, Andrea

    2008-01-01

    Sphingosine kinases (SK) catalyze the production of sphingosine-1-phosphate which in turn regulates cell responses such as proliferation and migration. Here, we show that exposure of the human endothelial cell line EA.hy 926 to hypoxia stimulates a increased SK-1, but not SK-2, mRNA, protein expression, and activity. This effect was due to stimulated SK-1 promoter activity which contains two putative hypoxia-inducible factor-responsive-elements (HRE). By deletion of one of the two HREs, hypoxia-induced promoter activation was abrogated. Furthermore, hypoxia upregulated the expression of HIF-1α and HIF-2α, and both contributed to SK-1 gene transcription as shown by selective depletion of HIF-1α or HIF-2α by siRNA. The hypoxia-stimulated SK-1 upregulation was functionally coupled to increased migration since the selective depletion of SK-1, but not of SK-2, by siRNAs abolished the migratory response. In summary, these data show that hypoxia upregulates SK-1 activity and results in an accelerated migratory capacity of endothelial cells. SK-1 may thus serve as an attractive therapeutic target to treat diseases associated with increased endothelial migration and angiogenesis such as cancer growth and progression

  8. Long noncoding RNA HOTAIR, a hypoxia-inducible factor-1α activated driver of malignancy, enhances hypoxic cancer cell proliferation, migration, and invasion in non-small cell lung cancer.

    Science.gov (United States)

    Zhou, Chunxia; Ye, Lincai; Jiang, Chuan; Bai, Jie; Chi, Yongbin; Zhang, Haibo

    2015-12-01

    Despite the fact that great advances have been made in the management of non-small cell lung cancer (NSCLC), the prognosis of advanced NSCLC remains very poor. HOX transcript antisense intergenic RNA (HOTAIR) has been identified as an oncogenic long noncoding RNA (lncRNA) that is involved in the progression of a variety of carcinomas and acts as a negative prognostic biomarker. Yet, little is known about the effect of HOTAIR in the hypoxic microenvironment of NSCLC. The expression and promoter activity of HOTAIR were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and luciferase reporter assay. The function of the hypoxia-inducible factor-1α (HIF-1α) binding site to hypoxia-responsive elements (HREs) in the HOTAIR promoter region was tested by luciferase reporter assay with nucleotide substitutions. The binding of HIF-1α to the HOTAIR promoter in vivo was confirmed by chromatin immunoprecipitation assay (CHIP) and electrophoretic mobility shift assay (EMSA). The effect of HIF-1α suppression by small interference RNA or YC-1 on HOTAIR expression was also determined. In the present study, we demonstrated that HOTAIR was upregulated by hypoxia in NSCLC cells. HOTAIR is a direct target of HIF-1α through interaction with putative HREs in the upstream region of HOTAIR in NSCLC cells. Furthermore, HIF-1α knockdown or inhibition could prevent HOTAIR upregulation under hypoxic conditions. Under hypoxic conditions, HOTAIR enhanced cancer cell proliferation, migration, and invasion. These data suggested that suppression of HOTAIR upon hypoxia of NSCLC could be a novel therapeutic strategy.

  9. Stromal Expression of Hypoxia Regulated Proteins Is an Adverse Prognostic Factor in Colorectal Carcinomas

    Directory of Open Access Journals (Sweden)

    Arjen H. G. Cleven

    2007-01-01

    Full Text Available Background: Hypoxia modifies the phenotype of tumors in a way that promotes tumor aggressiveness and resistance towards chemotherapy and radiotherapy. However, the expression and influence of hypoxia-regulated proteins on tumor biology are not well characterized in colorectal tumors. We studied the role of protein expression of hypoxia-inducible factor (HIF-1α, HIF-2α, carbonic anhydrase 9 (CA9 and glucose transporter 1 (GLUT1 in patients with colorectal adenocarcinomas. Methods: Expression of HIF-1α, HIF-2α, CA9 and GLUT1 was quantified by immunohistochemistry in 133 colorectal adenocarcinomas. The expression of hypoxia markers was correlated with clinicopathological variables and overall patient survival. Results: Expression of these hypoxia markers was detected in the epithelial compartment of the tumor cells as well as in tumor-associated stromal cells. Although tumor cells frequently showed expression of one or more of the investigated hypoxia markers, no correlation among these markers or with clinical response was found. However, within the tumor stroma, positive correlations between the hypoxia markers HIF-2α, CA9 and GLUT1 were observed. Furthermore expression of HIF-2α and CA9 in tumor-associated stroma were both associated with a significantly reduced overall survival. In the Cox proportional hazard model, stromal HIF-2α expression was an independent prognostic factor for survival. Conclusion: These observations show, that expression of hypoxia regulated proteins in tumor-associated stromal cells, as opposed to their expression in epithelial tumor cells, is associated with poor outcome in colorectal cancer. This study suggests that tumor hypoxia may influence tumor-associated stromal cells in a way that ultimately contributes to patient prognosis.

  10. HIF-2alpha-dependent PAI-1 induction contributes to angiogenesis in hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Geis, Theresa, E-mail: geis@biochem.uni-frankfurt.de [Institute of Biochemistry I—Pathobiochemistry, Faculty of Medicine, Goethe-University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Döring, Claudia, E-mail: C.Doering@em.uni-frankfurt.de [Dr. Senckenberg Institute of Pathology, Faculty of Medicine, Goethe-University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Popp, Rüdiger, E-mail: popp@vrc.uni-frankfurt.de [Institute for Vascular Signalling, Centre for Molecular Medicine, Faculty of Medicine Medicine, Goethe-University Frankfurt, Theodor-Stern-Kai 7, 60596 Frankfurt am Main (Germany); Grossmann, Nina, E-mail: grossmann@biochem.uni-frankfurt.de [Institute of Biochemistry I—Pathobiochemistry, Faculty of Medicine, Goethe-University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Fleming, Ingrid, E-mail: fleming@vrc.uni-frankfurt.de [Institute for Vascular Signalling, Centre for Molecular Medicine, Faculty of Medicine Medicine, Goethe-University Frankfurt, Theodor-Stern-Kai 7, 60596 Frankfurt am Main (Germany); Hansmann, Martin-Leo, E-mail: m.l.hansmann@em.uni-frankfurt.de [Dr. Senckenberg Institute of Pathology, Faculty of Medicine, Goethe-University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Dehne, Nathalie, E-mail: dehne@biochem.uni-frankfurt.de [Institute of Biochemistry I—Pathobiochemistry, Faculty of Medicine, Goethe-University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Brüne, Bernhard, E-mail: b.bruene@biochem.uni-frankfurt.de [Institute of Biochemistry I—Pathobiochemistry, Faculty of Medicine, Goethe-University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany)

    2015-02-01

    Hypoxia promotes progression of hepatocellular carcinoma (HCC), not only affecting tumor cell proliferation and invasion, but also angiogenesis and thus, increasing the risk of metastasis. Hypoxia inducible factors (HIF)-1α and -2α cause adaptation of tumors to hypoxia, still with uncertainties towards the angiogenic switch. We created a stable knockdown of HIF-1α and HIF-2α in HepG2 cells and generated cocultures of HepG2 spheroids with embryonic bodies as an in vitro tumor model mimicking the cancer microenvironment. The naturally occuring oxygen and nutrient gradients within the cocultures allow us to question the role of distinct HIF isoforms in regulating HCC angiogenesis. In cocultures with a HIF-2α knockdown, angiogenesis was attenuated, while the knockdown of HIF-1α was without effect. Microarray analysis identified plasminogen activator inhibitor 1 (PAI-1) as a HIF-2α target gene in HepG2 cells. The knockdown of PAI-1 in HepG2 cells also lowered angiogenesis. Blocking plasmin, the downstream target of PAI-1, with aprotinin in HIF-2α knockdown (k/d) cells proved a cause–effect relation and restored angiogenesis, with no effect on control cocultures. Suggestively, HIF-2α increases PAI-1 to lower concentrations of active plasmin, thereby supporting angiogenesis. We conclude that the HIF-2α target gene PAI-1 favors the angiogenic switch in HCC. - Highlights: • HepG2 were cocultured with stem cells to mimic a cancer microenvironment in vitro. • A knockdown of HIF-2α reduces angiogenesis. • PAI-1 was identified as a HIF-2α target gene in HCC by microarray analysis. • HIF-2α induces the angiogenic switch via inhibition of plasmin.

  11. HIF-2alpha-dependent PAI-1 induction contributes to angiogenesis in hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Geis, Theresa; Döring, Claudia; Popp, Rüdiger; Grossmann, Nina; Fleming, Ingrid; Hansmann, Martin-Leo; Dehne, Nathalie; Brüne, Bernhard

    2015-01-01

    Hypoxia promotes progression of hepatocellular carcinoma (HCC), not only affecting tumor cell proliferation and invasion, but also angiogenesis and thus, increasing the risk of metastasis. Hypoxia inducible factors (HIF)-1α and -2α cause adaptation of tumors to hypoxia, still with uncertainties towards the angiogenic switch. We created a stable knockdown of HIF-1α and HIF-2α in HepG2 cells and generated cocultures of HepG2 spheroids with embryonic bodies as an in vitro tumor model mimicking the cancer microenvironment. The naturally occuring oxygen and nutrient gradients within the cocultures allow us to question the role of distinct HIF isoforms in regulating HCC angiogenesis. In cocultures with a HIF-2α knockdown, angiogenesis was attenuated, while the knockdown of HIF-1α was without effect. Microarray analysis identified plasminogen activator inhibitor 1 (PAI-1) as a HIF-2α target gene in HepG2 cells. The knockdown of PAI-1 in HepG2 cells also lowered angiogenesis. Blocking plasmin, the downstream target of PAI-1, with aprotinin in HIF-2α knockdown (k/d) cells proved a cause–effect relation and restored angiogenesis, with no effect on control cocultures. Suggestively, HIF-2α increases PAI-1 to lower concentrations of active plasmin, thereby supporting angiogenesis. We conclude that the HIF-2α target gene PAI-1 favors the angiogenic switch in HCC. - Highlights: • HepG2 were cocultured with stem cells to mimic a cancer microenvironment in vitro. • A knockdown of HIF-2α reduces angiogenesis. • PAI-1 was identified as a HIF-2α target gene in HCC by microarray analysis. • HIF-2α induces the angiogenic switch via inhibition of plasmin

  12. Hypoxia perturbs aryl hydrocarbon receptor signaling and CYP1A1 expression induced by PCB 126 in human skin and liver-derived cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Vorrink, Sabine U. [Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA (United States); Department of Radiation Oncology, The University of Iowa, Iowa City, IA (United States); Severson, Paul L. [Department of Pharmacology and Toxicology, The University of Arizona, Tucson, AZ (United States); Kulak, Mikhail V. [Department of Surgery, The University of Iowa, Iowa City, IA (United States); Futscher, Bernard W. [Department of Pharmacology and Toxicology, The University of Arizona, Tucson, AZ (United States); Domann, Frederick E., E-mail: frederick-domann@uiowa.edu [Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA (United States); Department of Radiation Oncology, The University of Iowa, Iowa City, IA (United States); Department of Surgery, The University of Iowa, Iowa City, IA (United States)

    2014-02-01

    The aryl hydrocarbon receptor (AhR) is an important mediator of toxic responses after exposure to xenobiotics including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and dioxin-like polychlorinated biphenyls (PCBs). Activation of AhR responsive genes requires AhR dimerization with the aryl hydrocarbon receptor nuclear translocator (ARNT), a heterodimeric partner also shared by the hypoxia-inducible factor-1α (HIF-1α) protein. TCDD-stimulated AhR transcriptional activity can be influenced by hypoxia; however, it less well known whether hypoxia interferes with AhR transcriptional transactivation in the context of PCB-mediated AhR activation in human cells. Elucidation of this interaction is important in liver hepatocytes which extensively metabolize ingested PCBs and experience varying degrees of oxygen tension during normal physiologic function. This study was designed to assess the effect of hypoxia on AhR transcriptional responses after exposure to 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126). Exposure to 1% O{sub 2} prior to PCB 126 treatment significantly inhibited CYP1A1 mRNA and protein expression in human HepG2 and HaCaT cells. CYP1A1 transcriptional activation was significantly decreased upon PCB 126 stimulation under conditions of hypoxia. Additionally, hypoxia pre-treatment reduced PCB 126 induced AhR binding to CYP1 target gene promoters. Importantly, ARNT overexpression rescued cells from the inhibitory effect of hypoxia on XRE-luciferase reporter activity. Therefore, the mechanism of interference of the signaling crosstalk between the AhR and hypoxia pathways appears to be at least in part dependent on ARNT availability. Our results show that AhR activation and CYP1A1 expression induced by PCB 126 were significantly inhibited by hypoxia and hypoxia might therefore play an important role in PCB metabolism and toxicity. - Highlights: • Significant crosstalk exists between AhR and HIF-1α signaling. • Hypoxia perturbs PCB 126 induced AhR function and

  13. Forchlorfenuron disrupts SEPT9_i1 filaments and inhibits HIF-1.

    Directory of Open Access Journals (Sweden)

    Dikla Vardi-Oknin

    Full Text Available Forchlorfenuron (FCF is a synthetic plant cytokinin that has been shown to alter yeast and mammalian septin organization. Septins are a highly conserved family of GTP-binding cytoskeletal proteins. Mammalian septins are involved in diverse cellular processes including tumorigenesis. We have been studying the interaction between septin 9 isoform 1 (SEPT9_i1 and hypoxia inducible factor-1α (HIF-1α, the oxygen regulated subunit of HIF-1. HIF-1 is a key transcription factor in the hypoxic responses pathway, and its activation has been observed in carcinogenesis and numerous cancers. SEPT9_i1/HIF-1α interaction plays an important role in upregulation of HIF-1 transcriptional activity by preventing HIF-1α's ubiquitination and degradation leading to increased tumor growth and angiogenesis. We tested the hypothesis whether FCF affects SEPT9_i1 filamentous structures and consequently HIF-1 pathway in cancer cells. We showed that FCF suppresses tumorigenic properties, including proliferation, migration and transformation, in prostate cancer cells. FCF did not alter SEPT9_i1 steady state protein expression levels but it affected its filamentous structures and subcellular localization. FCF induced degradation of HIF-1α protein in a dose- and time-dependent manner. This inhibition was also shown in other common cancer types tested. Rapid degradation of HIF-1α protein levels was accompanied by respective inhibition in HIF-1α transcriptional activity. Moreover, HIF-1α protein half-life was markedly decreased in the presence of FCF compared with that in the absence of FCF. The FCF-induced degradation of HIF-1α was mediated in a significant part via the proteasome. To the best of our knowledge, this is the first demonstration of specific manipulation of septin filaments by pharmacological means having downstream inhibitory effects on the HIF-1 pathway.

  14. Expression and Function of Hypoxia Inducible Factor-1α and Vascular Endothelial Growth Factor in Pulp Tissue of Teeth under Orthodontic Movement

    Directory of Open Access Journals (Sweden)

    Fulan Wei

    2015-01-01

    Full Text Available Orthodontic force may lead to cell damage, circulatory disturbances, and vascular changes of the dental pulp, which make a hypoxic environment in pulp. In order to maintain the homeostasis of dental pulp, hypoxia will inevitably induce the defensive reaction. However, this is a complex process and is regulated by numerous factors. In this study, we established an experimental animal model of orthodontic tooth movement to investigate the effects of mechanical force on the expression of VEGF and HIF-1α in dental pulp. Histological analysis of dental pulp and expressions of HIF-1α and VEGF proteins in dental pulp were examined. The results showed that inflammation and vascular changes happened in dental pulp tissue in different periods. Additionally, there were significant changes in the expression of HIF-1α and VEGF proteins under orthodontic force. After application of mechanical load, expression of HIF-1α and VEGF was markedly positive in 1, 3, 7 d, and 2 w groups, and then it weakened in 4 w group. These findings suggested that the expression of HIF-1α and VEGF was enhanced by mechanical force. HIF-1α and VEGF may play an important role in retaining the homeostasis of dental pulp during orthodontic tooth movement.

  15. HIF-1α inhibition reverses multidrug resistance in colon cancer cells via downregulation of MDR1/P-glycoprotein.

    Directory of Open Access Journals (Sweden)

    Jianfang Chen

    Full Text Available Multidrug resistance (MDR is one of the major reasons chemotherapy-based treatments fail. Hypoxia is generally associated with tumor chemoresistance. However, the correlation between the heterodimeric hypoxia-inducible factor-1 (HIF-1 and the multidrug resistance (MDR1 gene/transporter P-glycoprotein (P-gp remains unclear. This study aims to explore the molecular mechanisms of reversing colon cancer MDR by focusing on the target gene HIF-1α.A chemotherapeutic sensitivity assay was used to observe the efficiency of MDR reversal in LoVo multicellular spheroids (MCS. The apoptotic level induced by different drugs was examined by flow cytometry (FCM. Binding of HIF-1α to the MDR1 gene promoter was evaluated by Chromatin immunoprecipitation (ChIP. The relationship between HIF-1α/P-gp expression and sensitivity to chemotherapy was analyzed.The sensitivity of LoVo MCS to all four chemotherapy drugs was decreased to varying degrees under hypoxic conditions. After silencing the HIF-1α gene, the sensitivities of LoVo MCS to all four chemotherapy drugs were restored. The apoptotic levels that all the drugs induced were all decreased to various extents in the hypoxic group. After silencing HIF-1α, the apoptosis level induced by all four chemotherapy drugs increased. The expression of HIF-1α and P-gp was significantly enhanced in LoVo MCS after treatment with hypoxia. Inhibiting HIF-1α significantly decreased the expression of MDR1/P-gp mRNA or protein in both the LoVo monolayers and LoVo MCS. The ChIP assay showed that HIF-1α was bound to the MDR1 gene promoter. Advanced colon carcinoma patients with expression of both HIF-1α and P-gp were more resistant to chemotherapy than that with non expression.HIF-1α inhibition reverses multidrug resistance in colon cancer cells via downregulation of MDR1/P-gp. The expression of HIF-1α and MDR1/P-gp can be used as a predictive marker for chemotherapy resistance in colon cancer.

  16. The novel hypoxic cytotoxin, TX-2098 has antitumor effect in pancreatic cancer; possible mechanism through inhibiting VEGF and hypoxia inducible factor-1α targeted gene expression

    International Nuclear Information System (INIS)

    Miyake, Kotaro; Nishioka, Masanori; Imura, Satoru; Batmunkh, Erdenebulgan; Uto, Yoshihiro; Nagasawa, Hideko; Hori, Hitoshi; Shimada, Mitsuo

    2012-01-01

    Tumor hypoxia has been considered to be a potential therapeutic target, because hypoxia is a common feature of solid tumors and is associated with their malignant phenotype. In the present study, we investigated the antitumor effect of a novel hypoxic cytotoxin, 3-[2-hydroxyethyl(methyl)amino]-2-quinoxalinecarbonitrile 1,4-dioxide (TX-2098) in inhibiting the expression of hypoxia inducible factor-1α (HIF-1α), and consequently vascular endothelial cell growth factor (VEGF) expression in pancreatic cancer. The antitumor effects of TX-2098 under hypoxia were tested against various human pancreatic cancer cell lines using WST-8 assay. VEGF protein induced pancreatic cancer was determined on cell-free supernatant by ELISA. Moreover, nude mice bearing subcutaneously (s.c.) or orthotopically implanted human SUIT-2 were treated with TX-2098. Tumor volume, survival and expression of HIF-1 and associated molecules were evaluated in treatment versus control groups. In vitro, TX-2098 inhibited the proliferation of various pancreatic cancer cell lines. In s.c model, tumors from nude mice injected with pancreatic cancer cells and treated with TX-2098 showed significant reductions in volume (P < 0.01 versus control). Quantitative real-time reverse transcription-PCR analysis revealed that TX-2098 significantly inhibited mRNA expression of the HIF-1 associated molecules, VEGF, glucose transporter 1 and Aldolase A (P < 0.01 versus control). These treatments also prolong the survival in orthotopic models. These results suggest that the effect of TX-2098 in pancreatic cancer might be correlated with the expression of VEGF and HIF-1 targeted molecules. -- Highlights: ► We designed and synthesized novel hypoxic cytoxin, TX-2098. ► TX-2098 inhibited the proliferation of human pancreatic cancer cells than TPZ. ► TX-2098 reduced VEGF protein level than TPZ. ► TX-2098 inhibited mRNA expression of VEGF, GLUT1 and Aldolase A, not HIF-1α. ► TX-2098 improved the survival in

  17. The novel hypoxic cytotoxin, TX-2098 has antitumor effect in pancreatic cancer; possible mechanism through inhibiting VEGF and hypoxia inducible factor-1{alpha} targeted gene expression

    Energy Technology Data Exchange (ETDEWEB)

    Miyake, Kotaro, E-mail: hif.panc@gmail.com [Department of Surgery, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503 (Japan); Nishioka, Masanori; Imura, Satoru; Batmunkh, Erdenebulgan [Department of Surgery, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503 (Japan); Uto, Yoshihiro [Department of Biological Science and Technology, Institute of Socio Technosciences, The University of Tokushima Graduate School, Tokushima 770-8503 (Japan); Nagasawa, Hideko [Laboratory of Pharmaceutical and Medicinal Chemistry, Gifu Pharmaceutical University, Gifu 501-1196 (Japan); Hori, Hitoshi [Department of Biological Science and Technology, Institute of Socio Technosciences, The University of Tokushima Graduate School, Tokushima 770-8503 (Japan); Shimada, Mitsuo [Department of Surgery, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503 (Japan)

    2012-08-01

    Tumor hypoxia has been considered to be a potential therapeutic target, because hypoxia is a common feature of solid tumors and is associated with their malignant phenotype. In the present study, we investigated the antitumor effect of a novel hypoxic cytotoxin, 3-[2-hydroxyethyl(methyl)amino]-2-quinoxalinecarbonitrile 1,4-dioxide (TX-2098) in inhibiting the expression of hypoxia inducible factor-1{alpha} (HIF-1{alpha}), and consequently vascular endothelial cell growth factor (VEGF) expression in pancreatic cancer. The antitumor effects of TX-2098 under hypoxia were tested against various human pancreatic cancer cell lines using WST-8 assay. VEGF protein induced pancreatic cancer was determined on cell-free supernatant by ELISA. Moreover, nude mice bearing subcutaneously (s.c.) or orthotopically implanted human SUIT-2 were treated with TX-2098. Tumor volume, survival and expression of HIF-1 and associated molecules were evaluated in treatment versus control groups. In vitro, TX-2098 inhibited the proliferation of various pancreatic cancer cell lines. In s.c model, tumors from nude mice injected with pancreatic cancer cells and treated with TX-2098 showed significant reductions in volume (P < 0.01 versus control). Quantitative real-time reverse transcription-PCR analysis revealed that TX-2098 significantly inhibited mRNA expression of the HIF-1 associated molecules, VEGF, glucose transporter 1 and Aldolase A (P < 0.01 versus control). These treatments also prolong the survival in orthotopic models. These results suggest that the effect of TX-2098 in pancreatic cancer might be correlated with the expression of VEGF and HIF-1 targeted molecules. -- Highlights: Black-Right-Pointing-Pointer We designed and synthesized novel hypoxic cytoxin, TX-2098. Black-Right-Pointing-Pointer TX-2098 inhibited the proliferation of human pancreatic cancer cells than TPZ. Black-Right-Pointing-Pointer TX-2098 reduced VEGF protein level than TPZ. Black-Right-Pointing-Pointer TX-2098

  18. [Altered expressions of alkane monooxygenase and hypoxia inducible factor-1α expression in lung tissue of rat hypoxic pulmonary hypertension].

    Science.gov (United States)

    Deng, Hua-jun; Yuan, Ya-dong

    2013-10-29

    To explore the altered expressions of alkane monooxygenase (AlkB) and hypoxia-inducible factor-1α (HIF-1α) in a rat model of hypoxic pulmonary arterial hypertension. Twenty Wistar rats were divided randomly into normal control and hypoxia groups after 1-week adaptive feeding. Hypoxia group was raised in a homemade organic glass tank with a 24-h continuous supply of air and nitrogen atmospheric mixed gas. And the oxygen concentration of (10.0 ± 0.5)% was controlled by oxygen monitoring control system. The control group was maintained in room air. Both groups stayed in the same room with the same diet. After 8 weeks, the level of mean pulmonary pressure (mPAP) was measured by right-heart catheterization, right ventricular hypertrophy index (RVHI) calculated by the ratio of right ventricle to left ventricle plus septum and hypoxic pulmonary vascular remodeling (HPSR) observed under microscope. And the levels of AlkB and HIF-1α mRNA and protein in lungs were measured by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot. At 8 weeks post-hypoxia, compared with the control group [11.0 ± 0.7 mm Hg (1 mm Hg = 0.133 kPa), 0.210 ± 0.035], the levels of mPAP and RVHI in hypoxia group (33.3 ± 1.3 mm Hg, 0.448 ± 0.013) increased significantly (both P < 0.05), the expressions of AlkB mRNA and protein in pulmonary tissue decreased significantly (0.338 ± 0.085 vs 0.688 ± 0.020, P < 0.01) (0.483 ± 0.052 vs 0.204 ± 0.010, P < 0.01), and the expressions of HIF-1α mRNA and protein increased significantly (0.790 ± 0.161 vs 0.422 ± 0.096, P < 0.01) (0.893 ± 0.080 vs 0.346 ± 0.008, P < 0.01). The down-regulation of AlkB in lung tissue may increase the activity of HIF-1 to participate in the occurrence and development of pulmonary hypertension.

  19. Intermittent Hypoxia Influences Alveolar Bone Proper Microstructure via Hypoxia-Inducible Factor and VEGF Expression in Periodontal Ligaments of Growing Rats

    Directory of Open Access Journals (Sweden)

    Shuji Oishi

    2016-09-01

    Full Text Available Intermittent hypoxia (IH recapitulates morphological changes in the maxillofacial bones in children with obstructive sleep apnea (OSA. Recently, we found that IH increased bone mineral density (BMD in the inter-radicular alveolar bone (reflecting enhanced osteogenesis in the mandibular first molar (M1 region in the growing rats, but the underlying mechanism remains unknown. In this study, we focused on the hypoxia-inducible factor (HIF pathway to assess the effect of IH by testing the null hypothesis of no significant differences in the mRNA-expression levels of relevant factors associated with the HIF pathway, between control rats and growing rats with IH. To test the null hypothesis, we investigated how IH enhances mandibular osteogenesis in the alveolar bone proper with respect to HIF-1α and vascular endothelial growth factor (VEGF in periodontal ligament (PDL tissues. Seven-week-old male Sprague–Dawley rats were exposed to IH for 3 weeks. The microstructure and BMD in the alveolar bone proper of the distal root of the mandibular M1 were evaluated using micro-computed tomography (micro-CT. Expression of HIF-1α and VEGF mRNA in PDL tissues were measured, whereas osteogenesis was evaluated by measuring mRNA levels for alkaline phosphatase (ALP and bone morphogenetic protein-2 (BMP-2. The null hypothesis was rejected: we found an increase in the expression of all of these markers after IH exposure. The results provided the first indication that IH enhanced osteogenesis of the mandibular M1 region in association with PDL angiogenesis during growth via HIF-1α in an animal model.

  20. Development of an oxygen-sensitive degradable peptide probe for the imaging of hypoxia-inducible factor-1-active regions in tumors.

    Science.gov (United States)

    Ueda, Masashi; Ogawa, Kei; Miyano, Azusa; Ono, Masahiro; Kizaka-Kondoh, Shinae; Saji, Hideo

    2013-12-01

    We aimed to develop a radiolabeled peptide probe for the imaging of hypoxia-inducible factor-1 (HIF-1)-active tumors. We synthesized the peptide probes that contain or lack an essential sequence of the oxygen-dependent degradation of HIF-1α in proteasomes ((123/125)I-DKOP30 or (125)I-mDKOP, respectively). The degradation of probes was evaluated in vitro using cell lysates containing proteasomes. In vivo biodistribution study, planar imaging, autoradiography, and comparison between probe accumulation and HIF-1 transcriptional activity were also performed. The (125)I-DKOP30 underwent degradation in a proteasome-dependent manner, while (125)I-mDKOP was not degraded. Biodistribution analysis showed (125)I-DKOP30 accumulation in tumors. The tumors were clearly visualized by in vivo imaging, and intratumoral distribution of (125)I-DKOP30 coincided with the HIF-1α-positive hypoxic regions. Tumoral accumulation of (125)I-DKOP30 was significantly correlated with HIF-1-dependent luciferase bioluminescence, while that of (125)I-mDKOP was not. (123)I-DKOP30 is a useful peptide probe for the imaging of HIF-1-active tumors.

  1. El factor inducible por la hipoxia y la actividad física hypoxia-inducible factor and physical activity

    Directory of Open Access Journals (Sweden)

    Juan Camilo Calderón Vélez

    2007-04-01

    Full Text Available Los animales superiores dependen de un adecuado flujo de oxígeno. Los mecanismos involucrados en los procesos de percibir la hipoxia y responder a ella se han ido aclarando, desde hace unos 15 años, con el descubrimiento de las subunidades α y β del factor inducible por la hipoxia (HIF, por su sigla en inglés y de las hidroxilasas involucradas en su regulación. Las especies reactivas de oxígeno (ERO, al parecer, también participan en el proceso de percibir y responder a la hipoxia. Las células musculares podrían ser un modelo útil para estudiar la interrelación hipoxia-ERO-HIF- respuesta celular, con importantes implicaciones básico-clínicas. Sin embargo, apenas comienza el estudio de esta relación en el músculo esquelético. Se revisan en este artículo algunos aspectos interesantes de la investigación en el músculo esquelético y se plantean algunas preguntas e hipótesis que podrían ser evaluadas en este tipo de células. Higher animals depend on an adequate oxygen flux. Mechanisms involved in the process of sensing and responding to hypoxia have become clearer in the last 15 years with the discovery of the y hypoxia-inducible factor (HIF subunits and hydroxylases involved in their regulation. Reactive oxygen species seem to play some role in the process of sensing and responding to hypoxia. Skeletal muscle cells seem to be a suitable model for studying the hypoxia-reactive oxygen species-HIF-cellular response relationship. Its study has important basic and clinic implications. However, the study of this relationship just begins. Some interesting aspects regarding skeletal muscle research are reviewed in this article, and some questions and hypotheses suitable for being evaluated with muscle cells are discussed.

  2. IGF-1R Promotes Symmetric Self-Renewal and Migration of Alkaline Phosphatase+ Germ Stem Cells through HIF-2α-OCT4/CXCR4 Loop under Hypoxia.

    Science.gov (United States)

    Kuo, Yung-Che; Au, Heng-Kien; Hsu, Jue-Liang; Wang, Hsiao-Feng; Lee, Chiung-Ju; Peng, Syue-Wei; Lai, Ssu-Chuan; Wu, Yu-Chih; Ho, Hong-Nerng; Huang, Yen-Hua

    2018-02-13

    Hypoxia cooperates with endocrine signaling to maintain the symmetric self-renewal proliferation and migration of embryonic germline stem cells (GSCs). However, the lack of an appropriate in vitro cell model has dramatically hindered the understanding of the mechanism underlying this cooperation. Here, using a serum-free system, we demonstrated that hypoxia significantly induced the GSC mesenchymal transition, increased the expression levels of the pluripotent transcription factor OCT4 and migration-associated proteins (SDF-1, CXCR4, IGF-1, and IGF-1R), and activated the cellular expression and translocalization of the CXCR4-downstream proteins ARP3/pFAK. The underlying mechanism involved significant IGF-1/IGF-1R activation of OCT4/CXCR4 expression through HIF-2α regulation. Picropodophyllin-induced inhibition of IGF-1R phosphorylation significantly suppressed hypoxia-induced SDF-1/CXCR4 expression and cell migration. Furthermore, transactivation between IGF-1R and CXCR4 was involved. In summary, we demonstrated that niche hypoxia synergistically cooperates with its associated IGF-1R signaling to regulate the symmetric division (self-renewal proliferation) and cell migration of alkaline phosphatase-positive GSCs through HIF-2α-OCT4/CXCR4 during embryogenesis. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  3. Potent and Selective Triazole-Based Inhibitors of the Hypoxia-Inducible Factor Prolyl-Hydroxylases with Activity in the Murine Brain.

    Directory of Open Access Journals (Sweden)

    Mun Chiang Chan

    Full Text Available As part of the cellular adaptation to limiting oxygen availability in animals, the expression of a large set of genes is activated by the upregulation of the hypoxia-inducible transcription factors (HIFs. Therapeutic activation of the natural human hypoxic response can be achieved by the inhibition of the hypoxia sensors for the HIF system, i.e. the HIF prolyl-hydroxylases (PHDs. Here, we report studies on tricyclic triazole-containing compounds as potent and selective PHD inhibitors which compete with the 2-oxoglutarate co-substrate. One compound (IOX4 induces HIFα in cells and in wildtype mice with marked induction in the brain tissue, revealing that it is useful for studies aimed at validating the upregulation of HIF for treatment of cerebral diseases including stroke.

  4. HIF- and Non-HIF-Regulated Hypoxic Responses Require the Estrogen-Related Receptor in Drosophila melanogaster

    Science.gov (United States)

    Li, Yan; Padmanabha, Divya; Gentile, Luciana B.; Dumur, Catherine I.; Beckstead, Robert B.; Baker, Keith D.

    2013-01-01

    Low-oxygen tolerance is supported by an adaptive response that includes a coordinate shift in metabolism and the activation of a transcriptional program that is driven by the hypoxia-inducible factor (HIF) pathway. The precise contribution of HIF-1a in the adaptive response, however, has not been determined. Here, we investigate how HIF influences hypoxic adaptation throughout Drosophila melanogaster development. We find that hypoxic-induced transcriptional changes are comprised of HIF-dependent and HIF-independent pathways that are distinct and separable. We show that normoxic set-points of carbohydrate metabolites are significantly altered in sima mutants and that these animals are unable to mobilize glycogen in hypoxia. Furthermore, we find that the estrogen-related receptor (dERR), which is a global regulator of aerobic glycolysis in larvae, is required for a competent hypoxic response. dERR binds to dHIFa and participates in the HIF-dependent transcriptional program in hypoxia. In addition, dERR acts in the absence of dHIFa in hypoxia and a significant portion of HIF-independent transcriptional responses can be attributed to dERR actions, including upregulation of glycolytic transcripts. These results indicate that competent hypoxic responses arise from complex interactions between HIF-dependent and -independent mechanisms, and that dERR plays a central role in both of these programs. PMID:23382692

  5. Novel therapeutic approach targeting the HIF-HRE system in the kidney.

    Science.gov (United States)

    Nangaku, Masaomi

    2009-01-01

    Recent studies emphasize the role of chronic hypoxia in the tubulointerstitium as a final common pathway to end-stage renal disease. Therefore, therapeutic approaches which target the chronic hypoxia should prove effective against a broad range of renal diseases. Many of hypoxia-triggered protective mechanisms are hypoxia inducible factor (HIF)-dependent. Although HIF-1 alpha and HIF-2 alpha share both structural and functional similarity, they have different localization and can contribute in a non-redundant manner. While gene transfer of constitutively active HIF has been shown effective, pharmacological approaches to activate HIF are more desirable. Oxygen-dependent activation of prolyl hydroxylases (PHD) regulates the amount of HIF by degradation of this transcription factor. Therefore, PHD inhibitors have been the focus of recent studies on novel strategies to stabilize HIF. Cobalt is one of the inhibitors of PHD, and stimulation of HIF with cobalt is effective in a variety of kidney disease models. Furthermore, crystal structures of the catalytic domain of human prolyl hydroxylase 2 have been clarified recently. The structure aids in the design of PHD selective inhibitors for the treatment of hypoxic tissue injury. Current advance has elucidated the detailed mechanism of hypoxia-induced transcription, giving hope for the development of novel therapeutic approaches against hypoxia.

  6. Cellular Oxygen Sensing: Crystal Structure of Hypoxia-Inducible Factor Prolyl Hydroxylase (PHD2)

    Energy Technology Data Exchange (ETDEWEB)

    McDonough,M.; Li, V.; Flashman, E.; Chowdhury, R.; Mohr, C.; Lienard, B.; Zondlo, J.; Oldham, N.; Clifton, I.; et al.

    2006-01-01

    Cellular and physiological responses to changes in dioxygen levels in metazoans are mediated via the posttranslational oxidation of hypoxia-inducible transcription factor (HIF). Hydroxylation of conserved prolyl residues in the HIF-{alpha} subunit, catalyzed by HIF prolyl-hydroxylases (PHDs), signals for its proteasomal degradation. The requirement of the PHDs for dioxygen links changes in dioxygen levels with the transcriptional regulation of the gene array that enables the cellular response to chronic hypoxia; the PHDs thus act as an oxygen-sensing component of the HIF system, and their inhibition mimics the hypoxic response. We describe crystal structures of the catalytic domain of human PHD2, an important prolyl-4-hydroxylase in the human hypoxic response in normal cells, in complex with Fe(II) and an inhibitor to 1.7 Angstroms resolution. PHD2 crystallizes as a homotrimer and contains a double-stranded {beta}-helix core fold common to the Fe(II) and 2-oxoglutarate-dependant dioxygenase family, the residues of which are well conserved in the three human PHD enzymes (PHD 1-3). The structure provides insights into the hypoxic response, helps to rationalize a clinically observed mutation leading to familial erythrocytosis, and will aid in the design of PHD selective inhibitors for the treatment of anemia and ischemic disease.

  7. β-N-oxalyl-L-α, β- diaminopropionic acid induces HRE expression by inhibiting HIF-prolyl hydroxylase-2 in normoxic conditions.

    Science.gov (United States)

    Eslavath, Ravi Kumar; Sharma, Deepshikha; Bin Omar, Nabil A M; Chikati, Rajasekhar; Teli, Mahesh Kumar; Rajanikant, G K; Singh, Surya S

    2016-11-15

    Hypoxia inducible factor (HIF)-1α, a subunit of HIF transcription factor, regulates cellular response to hypoxia. In normoxic conditions, it is hydroxylated by prolyl hydroxylase (PHD)-2 and targeted for proteosomal degradation. Drugs which inhibit PHD-2 have implications in conditions arising from insufficient blood supply. β-ODAP (β-N- oxalyl-L-α, β- diaminopropionic acid), a non-protein excitatory amino acid present in Lathyrus sativus, is an α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor agonist known to activate conventional protein kinase C and stabilize HIF-1α under normoxic conditions. However, the mechanism of HIF-1α stabilization by this compound is unknown. In silico approach was used to understand the mechanism of stabilization of HIF-1α which revealed β-ODAP interacts with key amino acid residues and Fe 2+ at the catalytic site of PHD-2. These results were further corroborated with luciferase HRE (hypoxia response element) reporter system in HeLa cells. Different chemical modulators of PHD-2 activity and HIF-1α levels were included in the study for comparison. Results obtained indicate that β-ODAP inhibits PHD-2 and facilitates HIF dependent HRE expression and hence, might be helpful in conditions arising from hypoxia. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. HIF-1α pathway: role, regulation and intervention for cancer therapy

    Directory of Open Access Journals (Sweden)

    Georgina N. Masoud

    2015-09-01

    Full Text Available Hypoxia-inducible factor-1 (HIF-1 has been recognized as an important cancer drug target. Many recent studies have provided convincing evidences of strong correlation between elevated levels of HIF-1 and tumor metastasis, angiogenesis, poor patient prognosis as well as tumor resistance therapy. It was found that hypoxia (low O2 levels is a common character in many types of solid tumors. As an adaptive response to hypoxic stress, hypoxic tumor cells activate several survival pathways to carry out their essential biological processes in different ways compared with normal cells. Recent advances in cancer biology at the cellular and molecular levels highlighted the HIF-1α pathway as a crucial survival pathway for which novel strategies of cancer therapy could be developed. However, targeting the HIF-1α pathway has been a challenging but promising progresses have been made in the past twenty years. This review summarizes the role and regulation of the HIF-1α in cancer, and recent therapeutic approaches targeting this important pathway.

  9. The anti-proliferative effect of L-carnosine correlates with a decreased expression of hypoxia inducible factor 1 alpha in human colon cancer cells.

    Directory of Open Access Journals (Sweden)

    Barbara Iovine

    Full Text Available In recent years considerable attention has been given to the use of natural substances as anticancer drugs. The natural antioxidant dipeptide L-carnosine belongs to this class of molecules because it has been proved to have a significant anticancer activity both in vitro and in vivo. Previous studies have shown that L-carnosine inhibits the proliferation of human colorectal carcinoma cells by affecting the ATP and Reactive Oxygen Species (ROS production. In the present study we identified the Hypoxia-Inducible Factor 1α (HIF-1α as a possible target of L-carnosine in HCT-116 cell line. HIF-1α protein is over-expressed in multiple types of human cancer and is the major cause of resistance to drugs and radiation in solid tumours. Of particular interest are experimental data supporting the concept that generation of ROS provides a redox signal for HIF-1α induction, and it is known that some antioxidants are able to suppress tumorigenesis by inhibiting HIF-1α. In the current study we found that L-carnosine reduces the HIF-1α protein level affecting its stability and decreases the HIF-1 transcriptional activity. In addition, we demonstrated that L-carnosine is involved in ubiquitin-proteasome system promoting HIF-1α degradation. Finally, we compared the antioxidant activity of L-carnosine with that of two synthetic anti-oxidant bis-diaminotriazoles (namely 1 and 2, respectively. Despite these three compounds have the same ability in reducing intracellular ROS, 1 and 2 are more potent scavengers and have no effect on HIF-1α expression and cancer cell proliferation. These findings suggest that an analysis of L-carnosine antioxidant pathway will clarify the mechanism underlying the anti-proliferative effects of this dipeptide on colon cancer cells. However, although the molecular mechanism by which L-carnosine down regulates or inhibits the HIF-1α activity has not been yet elucidated, this ability may be promising in treating hypoxia

  10. HIF-1α as a Regulator of BMP2-Induced Chondrogenic Differentiation, Osteogenic Differentiation, and Endochondral Ossification in Stem Cells

    Directory of Open Access Journals (Sweden)

    Nian Zhou

    2015-04-01

    Full Text Available Background/Aims: Joint cartilage defects are difficult to treat due to the limited self-repair capacities of cartilage. Cartilage tissue engineering based on stem cells and gene enhancement is a potential alternative for cartilage repair. Bone morphogenetic protein 2 (BMP2 has been shown to induce chondrogenic differentiation in mesenchymal stem cells (MSCs; however, maintaining the phenotypes of MSCs during cartilage repair since differentiation occurs along the endochondral ossification pathway. In this study, hypoxia inducible factor, or (HIF-1α, was determined to be a regulator of BMP2-induced chondrogenic differentiation, osteogenic differentiation, and endochondral bone formation. Methods: BMP2 was used to induce chondrogenic and osteogenic differentiation in stem cells and fetal limb development. After HIF-1α was added to the inducing system, any changes in the differentiation markers were assessed. Results: HIF-1α was found to potentiate BMP2-induced Sox9 and the expression of chondrogenesis by downstream markers, and inhibit Runx2 and the expression of osteogenesis by downstream markers in vitro. In subcutaneous stem cell implantation studies, HIF-1α was shown to potentiate BMP2-induced cartilage formation and inhibit endochondral ossification during ectopic bone/cartilage formation. In the fetal limb culture, HIF-1α and BMP2 synergistically promoted the expansion of the proliferating chondrocyte zone and inhibited chondrocyte hypertrophy and endochondral ossification. Conclusion: The results of this study indicated that, when combined with BMP2, HIF-1α induced MSC differentiation could become a new method of maintaining cartilage phenotypes during cartilage tissue engineering.

  11. Recent Advances in Developing Inhibitors for Hypoxia-Inducible Factor Prolyl Hydroxylases and Their Therapeutic Implications

    Directory of Open Access Journals (Sweden)

    So Yeon Kim

    2015-11-01

    Full Text Available Hypoxia-inducible factor (HIF prolyl hydroxylases (PHDs are members of the 2-oxoglutarate dependent non-heme iron dioxygenases. Due to their physiological roles in regulation of HIF-1α stability, many efforts have been focused on searching for selective PHD inhibitors to control HIF-1α levels for therapeutic applications. In this review, we first describe the structure of PHD2 as a molecular basis for structure-based drug design (SBDD and various experimental methods developed for measuring PHD activity. We further discuss the current status of the development of PHD inhibitors enabled by combining SBDD approaches with high-throughput screening. Finally, we highlight the clinical implications of small molecule PHD inhibitors.

  12. Transient HIF2A inhibition promotes satellite cell proliferation and muscle regeneration.

    Science.gov (United States)

    Xie, Liwei; Yin, Amelia; Nichenko, Anna S; Beedle, Aaron M; Call, Jarrod A; Yin, Hang

    2018-03-13

    The remarkable regeneration capability of skeletal muscle depends on coordinated proliferation and differentiation of satellite cells. The self-renewal of satellite cells is critical for long-term maintenance of muscle regeneration potential. Hypoxia profoundly affects the proliferation, differentiation, and self-renewal of cultured myoblasts. However, the physiological relevance of hypoxia and hypoxia signaling in satellite cells in vivo remains largely unknown. Here, we report that satellite cells are in an intrinsic hypoxic state in vivo and express hypoxia-inducible factor 2A (HIF2A). HIF2A promotes the stemness and long-term homeostatic maintenance of satellite cells by maintaining the quiescence, increasing the self-renewal and blocking the myogenic differentiation of satellite cells. HIF2A stabilization in satellite cells cultured under normoxia augmented their engraftment potential in regenerative muscle. Reversely, HIF2A ablation led to the depletion of satellite cells and the consequent regenerative failure in the long-term. In contrast, transient pharmacological inhibition of HIF2A accelerated muscle regeneration by increasing satellite cell proliferation and differentiation. Mechanistically, HIF2A induces the quiescence/self-renewal of satellite cells by binding the promoter of Spry1 gene and activating Spry1 expression. These findings suggest that HIF2A is a pivotal mediator of hypoxia signaling in satellite cells and may be therapeutically targeted to improve muscle regeneration.

  13. The effects of doxycycline and micronized purified flavonoid fraction on human vein wall remodeling are not hypoxia-inducible factor pathway-dependent.

    Science.gov (United States)

    Lim, Chung Sim; Kiriakidis, Serafim; Paleolog, Ewa M; Davies, Alun H

    2012-10-01

    Doxycycline and micronized purified flavonoid fraction (MPFF) modulate vein wall remodeling that may be associated with hypoxia in varicose veins (VVs), vein graft stenosis, and deep venous thrombosis. We recently reported that in vitro exposure of non-VV (NVVs) and VVs to hypoxic conditions activates the hypoxia-inducible factor (HIF) pathway. This study investigated the in vitro effects of doxycycline and MPFF on the HIF pathway in hypoxic NVVs and VVs. Six NVVs and six VVs obtained from surgery were used to prepare vein organ cultures, which were exposed to hypoxia (1% O(2)), with and without MPFF (10(-5) mol/L) or doxycycline (5 μg/mL) for 16 hours. The veins were analyzed for HIF-1α, HIF-2α, and their target gene expression, with real-time polymerase chain reaction and Western blot. The differences between gene expressions were tested with one-way analysis of variance with repeated measures, followed by the Dunnett test for multiple comparisons. P factor, B-cell lymphoma 2/adenovirus E1B 19-kDa protein-interacting protein 3, prolyl hydroxylase domain-2, and prolyl hydroxylase domain-3, was not significantly altered in NVVs and VVs exposed to hypoxia and treated with doxycycline or MPFF compared with those untreated. Doxycycline and MPFF at a concentration corresponding to a therapeutic dose do not alter the activation of the HIF pathway in NVV and VV organ cultures exposed to hypoxia. Our findings suggest vein wall remodeling actions in NVVs and VVs are likely not HIF-dependent. Copyright © 2012 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  14. NF-κB suppresses HIF-1α response by competing for P300 binding

    International Nuclear Information System (INIS)

    Mendonca, Daniela B.S.; Mendonca, Gustavo; Aragao, Francisco J.L.; Cooper, Lyndon F.

    2011-01-01

    Research highlights: → p65 completely blocked HIF-1α activity at the HRE on different cell lines. → p65 caused minor changes in HIF-1α and HIF-1α target genes mRNA expression. → p65 reduced transcription of VEGF promoter. → p65 competes with HIF-1α for p300. -- Abstract: Hypoxia has emerged as a key determinant of osteogenesis. HIF-1α is the transcription factor mediating hypoxia responses that include induction of VEGF and related bone induction. Inflammatory signals antagonize bone repair via the NF-κB pathway. The present investigation explored the functional relationship of hypoxia (HIF-1α function) and inflammatory signaling (NF-κB) in stem like and osteoprogenitor cell lines. The potential interaction between HIF-1α and NF-κB signaling was explored by co-transfection studies in hFOB with p65, HIF-1α and 9x-HRE-luc or HIF-1α target genes reporter plasmids. Nuclear cross-talk was directly tested using the mammalian Gal4/VP16 two-hybrid, and confirmed by co-immunoprecipitation/western blotting assays. The results show that inflammatory stimulation (TNF-α treatment) causes a marked inhibition of HIF-1α function at the HRE in all cell lines studied. Also, co-transfection with p65 expression vector leads to reduced hVEGFp transcription after DFO-induced hypoxia. However, TNF-α treatment had little effect on HIF-1α mRNA levels. The functional interaction of Gal4-HIF-1α and VP16-p300 fusion proteins is effectively blocked by expression of p65 in a dose dependent manner. It was concluded that NF-κB-mediated inflammatory signaling is able to block HIF-1α transactivation at HRE-encoding genes by direct competition for p300 binding at the promoter. Inflammation may influence the stem cell niche and tissue regeneration by influencing cellular responses to hypoxia.

  15. Hypoxia-Inducible Factors: Mediators of Cancer Progression; Prognostic and Therapeutic Targets in Soft Tissue Sarcomas

    International Nuclear Information System (INIS)

    Sadri, Navid; Zhang, Paul J.

    2013-01-01

    Soft-tissue sarcomas remain aggressive tumors that result in death in greater than a third of patients due to either loco-regional recurrence or distant metastasis. Surgical resection remains the main choice of treatment for soft tissue sarcomas with pre- and/or post-operational radiation and neoadjuvant chemotherapy employed in more advanced stage disease. However, in recent decades, there has been little progress in the average five-year survival for the majority of patients with high-grade soft tissue sarcomas, highlighting the need for improved targeted therapeutic agents. Clinical and preclinical studies demonstrate that tumor hypoxia and up-regulation of hypoxia-inducible factors (HIFs) is associated with decreased survival, increased metastasis, and resistance to therapy in soft tissue sarcomas. HIF-mediated gene expression regulates many critical aspects of tumor biology, including cell survival, metabolic programming, angiogenesis, metastasis, and therapy resistance. In this review, we discuss HIFs and HIF-mediated genes as potential prognostic markers and therapeutic targets in sarcomas. Many pharmacological agents targeting hypoxia-related pathways are in development that may hold therapeutic potential for treating both primary and metastatic sarcomas that demonstrate increased HIF expression

  16. Lesion Size Is Exacerbated in Hypoxic Rats Whereas Hypoxia-Inducible Factor-1 Alpha and Vascular Endothelial Growth Factor Increase in Injured Normoxic Rats: A Prospective Cohort Study of Secondary Hypoxia in Focal Traumatic Brain Injury.

    Science.gov (United States)

    Thelin, Eric Peter; Frostell, Arvid; Mulder, Jan; Mitsios, Nicholas; Damberg, Peter; Aski, Sahar Nikkhou; Risling, Mårten; Svensson, Mikael; Morganti-Kossmann, Maria Cristina; Bellander, Bo-Michael

    2016-01-01

    Hypoxia following traumatic brain injury (TBI) is a severe insult shown to exacerbate the pathophysiology, resulting in worse outcome. The aim of this study was to investigate the effects of a hypoxic insult in a focal TBI model by monitoring brain edema, lesion volume, serum biomarker levels, immune cell infiltration, as well as the expression of hypoxia-inducible factor-1 alpha (HIF-1α) and vascular endothelial growth factor (VEGF). Female Sprague-Dawley rats (n = 73, including sham and naive) were used. The rats were intubated and mechanically ventilated. A controlled cortical impact device created a 3-mm deep lesion in the right parietal hemisphere. Post-injury, rats inhaled either normoxic (22% O2) or hypoxic (11% O2) mixtures for 30 min. The rats were sacrificed at 1, 3, 7, 14, and 28 days post-injury. Serum was collected for S100B measurements using ELISA. Ex vivo magnetic resonance imaging (MRI) was performed to determine lesion size and edema volume. Immunofluorescence was employed to analyze neuronal death, changes in cerebral macrophage- and neutrophil infiltration, microglia proliferation, apoptosis, complement activation (C5b9), IgG extravasation, HIF-1α, and VEGF. The hypoxic group had significantly increased blood levels of lactate and decreased pO2 (p hypoxic animals (p hypoxic group at 1 day after trauma (p = 0.0868). No differences were observed between the groups in cytotoxic and vascular edema, IgG extravasation, neutrophils and macrophage aggregation, microglia proliferation, or C5b-9 expression. Hypoxia following focal TBI exacerbated the lesion size and neuronal loss. Moreover, there was a tendency to higher levels of S100B in the hypoxic group early after injury, indicating a potential validity as a biomarker of injury severity. In the normoxic group, the expression of HIF-1α and VEGF was found elevated, possibly indicative of neuro-protective responses occurring in this less severely injured group. Further studies are

  17. Hypoxia-Induced Signaling Promotes Prostate Cancer Progression: Exosomes Role as Messenger of Hypoxic Response in Tumor Microenvironment

    Science.gov (United States)

    Deep, Gagan; Panigrahi, Gati K.

    2017-01-01

    Prostate cancer (PCA) is the leading malignancy in men and the second leading cause of cancer-related deaths. Hypoxia (low O2 condition) is considered an early event in prostate carcinogenesis associated with an aggressive phenotype. In fact, clinically, hypoxia and hypoxia-related biomarkers are associated with treatment failure and disease progression. Hypoxia-inducible factor 1 (HIF-1) is the key factor that is activated under hypoxia, and mediates adaptation of cells to hypoxic conditions through regulating the expression of genes associated with angiogenesis, epithelial-to-mesenchymal transition (EMT), metastasis, survival, proliferation, metabolism, stemness, hormone-refractory progression, and therapeutic resistance. Besides HIF-1, several other signaling pathways including PI3K/Akt/mTOR, NADPH oxidase (NOX), Wnt/β-catenin, and Hedgehog are activated in cancer cells under hypoxic conditions, and also contribute in hypoxia-induced biological effects in HIF-1-dependent and -independent manners. Hypoxic cancer cells cause extensive changes in the tumor microenvironment both local and distant, and recent studies have provided ample evidence supporting the crucial role of nanosized vesicles “exosomes” in mediating hypoxia-induced tumor microenvironment remodeling. Exosomes’ role has been reported in hypoxia-induced angiogenesis, stemness, activation of cancer-associated fibroblasts (CAFs), and EMT. Together, existing literature suggests that hypoxia plays a predominant role in PCA growth and progression, and PCA could be effectively prevented and treated via targeting hypoxia/hypoxia-related signaling pathways. PMID:27279239

  18. Expression and function of hypoxia inducible factor-1 alpha in human melanoma under non-hypoxic conditions

    Directory of Open Access Journals (Sweden)

    Joshi Sandeep S

    2009-11-01

    Full Text Available Abstract Background Hypoxia inducible factor-1 alpha (HIF-1α protein is rapidly degraded under normoxic conditions. When oxygen tensions fall HIF-1α protein stabilizes and transactivates genes involved in adaptation to hypoxic conditions. We have examined the normoxic expression of HIF-1α RNA and protein in normal human melanocytes and a series of human melanoma cell lines isolated from radial growth phase (RGP, vertical growth phase (VGP and metastatic (MET melanomas. Results HIF-1α mRNA and protein was increased in RGP vs melanocytes, VGP vs RGP and MET vs VGP melanoma cell lines. We also detected expression of a HIF-1α mRNA splice variant that lacks part of the oxygen-dependent regulation domain in WM1366 and WM9 melanoma cells. Over-expression of HIF-1α and its splice variant in the RGP cell line SbCl2 resulted in a small increase in soft agar colony formation and a large increase in matrigel invasion relative to control transfected cells. Knockdown of HIF-1α expression by siRNA in the MET WM9 melanoma cell line resulted in a large decrease in both soft agar colony formation and matrigel invasion relative to cells treated with non-specific siRNA. There is a high level of ERK1/2 phosphorylation in WM9 cells, indicating an activated Ras-Raf-MEK-ERK1/2 MAPK pathway. Treatment of WM9 cells with 30 μM U0126 MEK inhibitor, decreased ERK1/2 phosphorylation and resulted in a decrease in HIF-1α expression. However, a 24 h treatment with 10 μM U0126 totally eliminated Erk1/2 phosphorylation, but did not change HIF-1alpha levels. Furthermore, siRNA knockdown of MEK siRNA did not change HIF-1alpha levels. Conclusion We speculate that metabolic products of U0126 decrease HIF-1alpha expression through "off target" effects. Overall our data suggest that increased HIF-1α expression under normoxic conditions contributes to some of the malignant phenotypes exhibited by human melanoma cells. The expanded role of HIF-1α in melanoma biology increases

  19. Chronic cerebral hypoperfusion-induced impairment of Aβ clearance requires HB-EGF-dependent sequential activation of HIF1α and MMP9.

    Science.gov (United States)

    Ashok, Anushruti; Rai, Nagendra Kumar; Raza, Waseem; Pandey, Rukmani; Bandyopadhyay, Sanghamitra

    2016-11-01

    Chronic cerebral hypoperfusion (CCH) manifests Alzheimer's Disease (AD) neuropathology, marked by increased amyloid beta (Aβ). Besides, hypoxia stimulates Heparin-binding EGF-like growth factor (HB-EGF) mRNA expression in the hippocampus. However, involvement of HB-EGF in CCH-induced Aβ pathology remains unidentified. Here, using Bilateral Common Carotid Artery Occlusion mouse model, we explored the mechanism of HB-EGF regulated Aβ induction in CCH. We found that HB-EGF inhibition suppressed, while exogenous-HB-EGF triggered hippocampal Aβ, proving HB-EGF-dependent Aβ increase. We also detected that HB-EGF affected the expression of primary Aβ transporters, receptor for advanced glycation end-products (RAGE) and lipoprotein receptor-related protein-1 (LRP-1), indicating impaired Aβ clearance across the blood-brain barrier (BBB). An HB-EGF-dependent loss in BBB integrity supported impaired Aβ clearance. The effect of HB-EGF on Amyloid Precursor Protein pathway was relatively insignificant, suggesting a lesser effect on Aβ generation. Delving into BBB disruption mechanism demonstrated HB-EGF-mediated stimulation of Matrix metalloprotease-9 (MMP9), which affected BBB via HB-EGF-ectodomain shedding and epidermal growth factor receptor activation. Examining the intersection of HB-EGF-regulated pathway and hypoxia revealed HB-EGF-dependent increase in transcription factor, Hypoxia-inducible factor-1alpha (HIF1α). Further, via binding to hypoxia-responsive elements in MMP9 gene, HIF1α stimulated MMP9 expression, and therefore appeared as a prominent intermediary in HB-EGF-induced BBB damage. Overall, our study reveals the essential role of HB-EGF in triggering CCH-mediated Aβ accumulation. The proposed mechanism involves an HB-EGF-dependent HIF1α increase, generating MMP9 that stimulates soluble-HB-EGF/EGFR-induced BBB disintegration. Consequently, CCH-mediated hippocampal RAGE and LRP-1 deregulation together with BBB damage impair Aβ transport and clearance

  20. Targeting the ROS-HIF-1-endothelin axis as a therapeutic approach for the treatment of obstructive sleep apnea-related cardiovascular complications.

    Science.gov (United States)

    Belaidi, Elise; Morand, Jessica; Gras, Emmanuelle; Pépin, Jean-Louis; Godin-Ribuot, Diane

    2016-12-01

    Obstructive sleep apnea (OSA) is now recognized as an independent and important risk factor for cardiovascular diseases such as hypertension, coronary heart disease, heart failure and stroke. Clinical and experimental data have confirmed that intermittent hypoxia is a major contributor to these deleterious consequences. The repetitive occurrence of hypoxia-reoxygenation sequences generates significant amounts of free radicals, particularly in moderate to severe OSA patients. Moreover, in addition to hypoxia, reactive oxygen species (ROS) are potential inducers of the hypoxia inducible transcription factor-1 (HIF-1) that promotes the transcription of numerous adaptive genes some of which being deleterious for the cardiovascular system, such as the endothelin-1 gene. This review will focus on the involvement of the ROS-HIF-1-endothelin signaling pathway in OSA and intermittent hypoxia and discuss current and potential therapeutic approaches targeting this pathway to treat or prevent cardiovascular disease in moderate to severe OSA patients. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Targeting the ROS-HIF-1-endothelin axis as a therapeutic approach for the treatment of obstructive sleep apnea-related cardiovascular complications

    Science.gov (United States)

    Belaidi, Elise; Morand, Jessica; Gras, Emmanuelle; Pépin, Jean-Louis; Godin-Ribuot, Diane

    2016-01-01

    Obstructive sleep apnea (OSA) is now recognized as an independent and important risk factor for cardiovascular diseases such as hypertension, coronary heart disease, heart failure and stroke. Clinical and experimental data have confirmed that intermittent hypoxia is a major contributor to these deleterious consequences. The repetitive occurrence of hypoxia-reoxygenation sequences generates significant amounts of free radicals, particularly in moderate to severe OSA patients. Moreover, in addition to hypoxia, reactive oxygen species (ROS) are potential inducers of the hypoxia inducible transcription factor-1 (HIF-1) that promotes the transcription of numerous adaptive genes some of which being deleterious for the cardiovascular system, such as the endothelin-1 gene. This review will focus on the involvement of the ROS-HIF-1-endotelin signaling pathway in OSA and intermittent hypoxia and discuss current and potential therapeutic approaches targeting this pathway to treat or prevent cardiovascular disease in moderate to severe OSA patients. PMID:27492897

  2. β2-Adrenergic Receptor-Mediated HIF-1α Upregulation Mediates Blood Brain Barrier Damage in Acute Cerebral Ischemia

    Directory of Open Access Journals (Sweden)

    Yanyun Sun

    2017-08-01

    Full Text Available Disruption of the blood brain barrier (BBB within the thrombolytic time window is an antecedent event to intracerebral hemorrhage in ischemic stroke. Our recent studies showed that 2-h cerebral ischemia induced BBB damage in non-infarcted area and secreted matrix metalloproteinase-2 (MMP-2 accounted for this disruption. However, the factors that affect MMP-2 secretion and regulate BBB damage remains unknown. Since hypoxia-inducible factor-1 alpha (HIF-1α was discovered as a mater regulator in hypoxia, we sought to investigate the roles of HIF-1α in BBB damage as well as the factors regulating HIF-1α expression in the ischemic brain. in vivo rat middle cerebral artery occlusion (MCAO and in vitro oxygen glucose deprivation (OGD models were used to mimic ischemia. Pretreatment with HIF-1α inhibitor YC-1 significantly inhibited 2-h MCAO-induced BBB damage, which was accompanied by suppressed occludin degradation and vascular endothelial growth factor (VEGF mRNA upregulation. Interestingly, β2-adrenergic receptor (β2-AR antagonist ICI 118551 attenuated ischemia-induced BBB damage by regulating HIF-1α expression. Double immunostaining showed that HIF-1α was upregulated in ischemic neurons but not in astrocytes andendothelial cells. Of note, HIF-1α inhibition with inhibitor YC-1 or siRNA significantly prevented OGD-induced VEGF upregulation as well as the secretion of VEGF and MMP-2 in neurons. More importantly, blocking β2-AR with ICI 118551 suppressedHIF-1α upregulation in ischemic neurons and attenuated occludin degradation induced by the conditioned media of OGD-treatedneurons. Taken together, blockade of β2-AR-mediated HIF-1α upregulation mediates BBB damage during acute cerebral ischemia. These findings provide new mechanistic understanding of early BBB damage in ischemic stroke and may help reduce thrombolysis-related hemorrhagic complications.

  3. HIF1-alpha overexpression indicates a good prognosis in early stage squamous cell carcinomas of the oral floor

    Directory of Open Access Journals (Sweden)

    Joos Ulrich

    2005-07-01

    Full Text Available Abstract Background Hypoxia-inducible factor 1 (HIF-1 is a transcription factor, which plays a central role in biologic processes under hypoxic conditions, especially concerning tumour angiogenesis. HIF-1α is the relevant, oxygen-dependent subunit and its overexpression has been associated with a poor prognosis in a variety of malignant tumours. Therefore, HIF-1α expression in early stage oral carcinomas was evaluated in relation to established clinico-pathological features in order to determine its value as a prognostic marker. Methods 85 patients with histologically proven surgically treated T1/2 squamous cell carcinoma (SCC of the oral floor were eligible for the study. Tumor specimens were investigated by means of tissue micro arrays (TMAs and immunohistochemistry for the expression of HIF-1. Correlations between clinical features and the expression of HIF-1 were evaluated by Kaplan-Meier curves, log-rank tests and multivariate Cox regression analysis. Results HIF-1α was frequently overexpressed in a probably non-hypoxia related fashion. The expression of HIF-1α was related with a significantly improved 5-year survival rate (p Conclusion HIF-1α overexpression is an indicator of favourable prognosis in T1 and T2 SCC of the oral floor. Node negative patients lacking HIF-1α expression may therefore be considered for adjuvant radiotherapy.

  4. Inhibition of Hypoxia Inducible Factor Alpha and Astrocyte-Elevated Gene-1 Mediates Cryptotanshinone Exerted Antitumor Activity in Hypoxic PC-3 Cells

    Directory of Open Access Journals (Sweden)

    Hyo-Jeong Lee

    2012-01-01

    Full Text Available Although cryptotanshinone (CT was known to exert antitumor activity in several cancers, its molecular mechanism under hypoxia still remains unclear. Here, the roles of AEG-1 and HIF-1α in CT-induced antitumor activity were investigated in hypoxic PC-3 cells. CT exerted cytotoxicity against prostate cancer cells and suppressed HIF-1α accumulation and AEG-1 expression in hypoxic PC-3 cells. Also, AEG-1 was overexpressed in prostate cancer cells. Interestingly, HIF-1α siRNA transfection enhanced the cleavages of caspase-9,3, and PAPR and decreased expression of Bcl-2 and AEG1 induced by CT in hypoxic PC-3 cells. Of note, DMOG enhanced the stability of AEG-1 and HIF-1α during hypoxia. Additionally, CT significantly reduced cellular level of VEGF in PC-3 cells and disturbed tube formation of HUVECs. Consistently, ChIP assay revealed that CT inhibited the binding of HIF-1α to VEGF promoter. Furthermore, CT at 10 mg/kg suppressed the growth of PC-3 cells in BALB/c athymic nude mice by 46.4% compared to untreated control. Consistently, immunohistochemistry revealed decreased expression of Ki-67, CD34, VEGF, carbonic anhydrase IX, and AEG-1 indices in CT-treated group compared to untreated control. Overall, our findings suggest that CT exerts antitumor activity via inhibition of HIF-1α, AEG1, and VEGF as a potent chemotherapeutic agent.

  5. The Long Non-coding RNA HIF1A-AS2 Facilitates the Maintenance of Mesenchymal Glioblastoma Stem-like Cells in Hypoxic Niches

    Directory of Open Access Journals (Sweden)

    Marco Mineo

    2016-06-01

    Full Text Available Long non-coding RNAs (lncRNAs have an undefined role in the pathobiology of glioblastoma multiforme (GBM. These tumors are genetically and phenotypically heterogeneous with transcriptome subtype-specific GBM stem-like cells (GSCs that adapt to the brain tumor microenvironment, including hypoxic niches. We identified hypoxia-inducible factor 1 alpha-antisense RNA 2 (HIF1A-AS2 as a subtype-specific hypoxia-inducible lncRNA, upregulated in mesenchymal GSCs. Its deregulation affects GSC growth, self-renewal, and hypoxia-dependent molecular reprogramming. Among the HIF1A-AS2 interactome, IGF2BP2 and DHX9 were identified as direct partners. This association was needed for maintenance of expression of their target gene, HMGA1. Downregulation of HIF1A-AS2 led to delayed growth of mesenchymal GSC tumors, survival benefits, and impaired expression of HMGA1 in vivo. Our data demonstrate that HIF1A-AS2 contributes to GSCs’ speciation and adaptation to hypoxia within the tumor microenvironment, acting directly through its interactome and targets and indirectly by modulating responses to hypoxic stress depending on the subtype-specific genetic context.

  6. Role of Hypoxia-inducible factor-1 and its target genes in human lung adenocarcinoma cells after photon- versus carbon ion irradiation; Expression HIF-1-abhaengiger Gene in humanen Lungenadenokarzinom (A549)-Zellen und deren Regulation nach Photonen- und Schwerionenbestrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Bill, Verena Maria

    2013-11-26

    Exposed to hypoxia tumor cells are notably resistant to photon irradiation. The hypoxiainducible transcription factor 1α (HIF-1α) seems to play a fundamental role in this resistance, while its role after heavy-ion beam remains unknown. The intention of this study was to determine how A549-cells (non-small-cell lung carcinoma) react in different oxygenation states after irradiation with photons or heavy ions, particularly in regards to their expression of HIF-1 target genes. Resistance of hypoxic A549 cells after photon irradiation was documented by cellular and clonogenic survival. In contrast, cellular survival after heavy-ion irradiation in hypoxic cells was not elevated to normoxic cells. Among the oxygen dependent regulation of HIF-1 target genes, gene expression analyses showed an increased expression of GLUT-1, LDH-A, PDK-1 and VEGF after photon irradiation but not after heavy-ion irradiation after 48 hours in normoxic cells. As expected, CDKN1A as inhibitor of cell cycle progression showed higher expression after both radiation forms; interestingly CDKN1A was also in an oxygen dependent manner lightly upregulated. In western blot analyses we demonstrated a significant increase of HIF-1 and GLUT-1 caused by hypoxia, but only a tendency of increased protein level in hypoxia after photon irradiation and no changes after heavy-ion irradiation. Significantly higher protein level of secreted VEGF-A could be measured 72 hours after photon irradiation in normoxic cells by ELISA analyses. Controversially discussed, I could not detect an association between HIF-1 and SCF or Trx-1 in A549-cells in this study. Whereas Trx-1-expression was neither influenced by changed oxygen partial pressure nor irradiation, I could show increased SCF mRNA by quantitative Real Time-PCR and secreted protein level by ELISA after photon irradiation independent of oxygen state. In summary, this study showed that HIF-1 and its target genes (GLUT-1, LDHA; PDK, VEGF) and also SCF was

  7. Induction of erythropoiesis by hypoxia-inducible factor prolyl hydroxylase inhibitors without promotion of tumor initiation, progression, or metastasis in a VEGF-sensitive model of spontaneous breast cancer

    Directory of Open Access Journals (Sweden)

    Seeley TW

    2017-03-01

    Full Text Available Todd W Seeley, Mark D Sternlicht, Stephen J Klaus, Thomas B Neff, David Y Liu Therapeutics R&D, FibroGen, Inc., San Francisco, CA, USA Abstract: The effects of pharmacological hypoxia-inducible factor (HIF stabilization were investigated in the MMTV-Neundl-YD5 (NeuYD mouse model of breast cancer. This study first confirmed the sensitivity of this model to increased vascular endothelial growth factor (VEGF, using bigenic NeuYD;MMTV-VEGF-25 mice. Tumor initiation was dramatically accelerated in bigenic animals. Bigenic tumors were also more aggressive, with shortened doubling times and increased lung metastasis as compared to NeuYD controls. In separate studies, NeuYD mice were treated three times weekly from 7 weeks of age until study end with two different HIF prolyl hydroxylase inhibitors (HIF-PHIs, FG-4497 or roxadustat (FG-4592. In NeuYD mice, HIF-PHI treatments elevated erythropoiesis markers, but no differences were detected in tumor onset or the phenotypes of established tumors. Keywords: cancer progression, erythropoiesis, hypoxia-inducible factor, hypoxia-inducible factor prolyl hydroxylase inhibitors, vascular endothelial growth factor, MMTV-Neu breast cancer model

  8. Immunohistochemical detection of osteopontin in advanced head-and-neck cancer: Prognostic role and correlation with oxygen electrode measurements, hypoxia-inducible-factor-1α-related markers, and hemoglobin levels

    International Nuclear Information System (INIS)

    Bache, Matthias; Reddemann, Rolf; Said, Harun M.; Holzhausen, Hans-Juergen; Taubert, Helge; Becker, Axel; Kuhnt, Thomas; Haensgen, Gabriele; Dunst, Juergen; Vordermark, Dirk

    2006-01-01

    Purpose: The tumor-associated glycoprotein osteopontin (OPN) is discussed as a plasma marker of tumor hypoxia. However, the association of immunohistochemical OPN expression in tumor sections with tumor oxygenation parameters (HF5, median pO 2 ), the hypoxia-related markers hypoxia-inducible factor-1α (HIF-1α) and carbonic anhydrase IX (CAIX), or hemoglobin and systemic vascular endothelial growth factor (VEGF) levels has not been investigated. Methods and Materials: Tumor tissue sections of 34 patients with advanced head-and-neck cancer treated with radiotherapy were assessed by immunochemistry for the expression of OPN, HIF-1α, and CA IX. Relationship of OPN expression with tumor oxygenation parameters (HF5, median pO 2 ), HIF-1α and CA IX expression, hemoglobin and serum VEGF level, and clinical parameters was studied. Results: Bivariate analysis showed a significant correlation of positive OPN staining with low hemoglobin level (p = 0.02), high HIF-1α expression (p = 0.02), and high serum vascular endothelial growth factor level (p = 0.02) for advanced head-and-neck cancer. Furthermore, considering the 31 Stage IV patients, the median pO 2 correlated significantly with the OPN expression (p = 0.02). OPN expression alone had only a small impact on prognosis. However, in a univariate Cox proportional hazard regression model, the expression of either OPN or HIF-1α or CA IX was associated with a 4.1-fold increased risk of death (p = 0.02) compared with negativity of all three markers. Conclusion: Osteopontin expression detected immunohistochemically is associated with oxygenation parameters in advanced head-and-neck cancer. When the results of OPN, HIF-1α, and CA IX immunohistochemistry are combined into a hypoxic profile, a strong and statistically significant impact on overall survival is found

  9. Proteomic Alterations in Response to Hypoxia Inducible Factor 2α in Normoxic Neuroblastoma Cells.

    Science.gov (United States)

    Cimmino, Flora; Pezone, Lucia; Avitabile, Marianna; Persano, Luca; Vitale, Monica; Sassi, Mauro; Bresolin, Silvia; Serafin, Valentina; Zambrano, Nicola; Scaloni, Andrea; Basso, Giuseppe; Iolascon, Achille; Capasso, Mario

    2016-10-07

    Hypoxia inducible factor (HIF)-2α protein expression in solid tumors promotes stem-like phenotype in cancer stem cells and increases tumorigenic potential in nonstem cancer cells. Recently, we have shown that HIF-1/2α gene expression is correlated to neuroblastoma (NB) poor survival and to undifferentiated tumor state; HIF-2α protein was demonstrated to enhance aggressive features of the disease. In this study, we used proteomic experiments on NB cells to investigate HIF-2α downstream-regulated proteins or pathways with the aim of providing novel therapeutic targets or bad prognosis markers. We verified that pathways mostly altered by HIF-2α perturbation are involved in tumor progression. In particular, HIF-2α induces alteration of central metabolism and splicing control pathways. Simultaneously, WNT, RAS/MAPK, and PI3K/AKT activity or expression are affected and may impact the sensitivity and the intensity of HIF-2α-regulated pathways. Furthermore, genes coding the identified HIF-2α-related markers built a signature able to stratify NB patients with unfavorable outcome. Taken together, our findings underline the relevance of dissecting the downstream effects of a poor survival marker in developing targeted therapy and improving patient stratification. Future prospective studies are needed to translate the use of these data into the clinical practice.

  10. Necrosis related HIF-1α expression predicts prognosis in patients with endometrioid endometrial carcinoma

    International Nuclear Information System (INIS)

    Seeber, Laura MS; Horrée, Nicole; Groep, Petra van der; Wall, Elsken van der; Verheijen, René HM; Diest, Paul J van

    2010-01-01

    Hypoxia inducible factor 1α (HIF-1α) plays an essential role in the adaptive response of cells to hypoxia and is associated with aggressive tumour behaviour. We have shown p27 kip1 , which is generally reduced in endometrial cancer, to be re-expressed in hypoxic regions. This possibly contributes to survival of cancer cells. The aim of this study was to evaluate the prognostic value of HIF-1α and p27 kip expression in patients with endometrioid endometrial cancer. Expression levels of HIF-1α, CAIX, Glut-1, and p27 kip1 were analyzed by immunohistochemistry. Percentage of positive cells, staining pattern (perinecrotic, diffuse, or mixed) and presence of necrosis were noted. Necrosis was correlated with shortened disease free survival (DFS) (p = 0.008) and overall survival (OS) (p = 0.045). For DFS, perinecrotic HIF-1α expression was also prognostic (p = 0.044). Moreover, high p27 kip1 expression was an additional prognostic factor for these patients with perinecrotic HIF-1α expression. In multivariate Cox regression, perinecrotic HIF-expression emerged as an independent prognostic factor. Perinecrotic HIF-1α expression was significantly associated with CAIX and Glut-1 expression, pointing towards functional HIF-1. In patients with endometrioid endometrial cancer, necrosis and necrosis-related expression of HIF-1α are important prognostic factors. More aggressive adjuvant treatment might be necessary to improve the outcome of patients with these characteristics

  11. Ginsenoside Rg3 enhances radiosensitization of hypoxic oesophageal cancer cell lines through vascular endothelial growth factor and hypoxia inducible factor 1α.

    Science.gov (United States)

    Ge, Xiaolin; Zhen, Fuxi; Yang, Baixia; Yang, Xi; Cai, Jing; Zhang, Chi; Zhang, Sheng; Cao, Yuandong; Ma, Jianxin; Cheng, Hongyan; Sun, Xinchen

    2014-06-01

    To determine if the pretreatment of hypoxic human oesophageal carcinoma cell lines (EC109, TE1 and KYSE170) with ginsenoside Rg3 (Rg3) increases their radiosensitivity to X-rays. The growth inhibitory effect of different Rg3 concentrations was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay. Radiation sensitivity was measured using a clone formation assay and flow cytometry was used to measure the effects of Rg3 on radiation-induced apoptosis. Western blot analysis was used to measure the effects of Rg3 on the levels of hypoxia inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF). Rg3 inhibited EC109, TE1 and KYSE170 cell growth in a dose- and time-dependent manner. Pretreatment with 10 µmol/ml Rg3 increased EC109, TE1 and KYSE170 radiosensitivity. Rg3 plus radiation significantly increased the apoptosis rate compared with radiation alone. Rg3 also decreased VEGF and HIF-1α protein levels in EC109 cells in a dose-dependent manner. The combination of Rg3 and radiation increased the fragmentation of double-stranded DNA. Rg3 enhanced the radiosensitivity of human oesophageal carcinoma cell lines cultured under hypoxic conditions possibly by downregulating VEGF and HIF-1α protein levels. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  12. 6-Mercaptopurine, an activator of Nur77, enhances transcriptional activity of HIF-1alpha resulting in new vessel formation.

    Science.gov (United States)

    Yoo, Y-G; Na, T-Y; Yang, W-K; Kim, H-J; Lee, I-K; Kong, G; Chung, J-H; Lee, M-O

    2007-05-31

    Hypoxia-inducible factor-1alpha (HIF-1alpha) plays a central role in oxygen homeostasis. Previously, we reported that the orphan nuclear receptor Nur77 functions in stabilizing HIF-1alpha. Here, we demonstrate that 6-mercaptopurine (6-MP), an activator of the NR4A family members, enhances transcriptional activity of HIF-1. 6-MP enhanced the protein-level of HIF-1alpha as well as vascular endothelial growth factor (VEGF) in a dose- and time-dependent manner. The induction of HIF-1alpha was abolished by the transfection of either a dominant-negative Nur77 mutant or si-Nur77, indicating a critical role of Nur77 in the 6-MP action. The HIF-1alpha protein level remained up to 60 min in the presence of 6-MP when de novo protein synthesis was blocked by cycloheximide, suggesting that 6-MP induces stabilization of the HIF-1alpha protein. The fact that 6-MP decreased the association of HIF-1alpha with von Hippel-Lindau protein and the acetylation of HIF-1alpha, may explain how 6-MP induced stability of HIF-1alpha. Further, 6-MP induced the transactivation function of HIF-1alpha by recruiting co-activator cyclic-AMP-response-element-binding protein. Finally, 6-MP enhanced the expression of HIF-1alpha and VEGF, and the formation of capillary tubes in human umbilical vascular endothelial cells. Together, our results provide a new insight for 6-MP action in the stabilization of HIF-1alpha and imply a potential application of 6-MP in hypoxia-associated human vascular diseases.

  13. Hypoxia inducible factor-1 is activated by transcriptional co-activator with PDZ-binding motif (TAZ) versus WWdomain-containing oxidoreductase (WWOX) in hypoxic microenvironment of bone metastasis from breast cancer.

    Science.gov (United States)

    Bendinelli, Paola; Maroni, Paola; Matteucci, Emanuela; Luzzati, Alessandro; Perrucchini, Giuseppe; Desiderio, Maria Alfonsina

    2013-07-01

    The hypoxic microenvironment of bone marrow favours the bone metastasis process. Hypoxia inducible factor (HIF)-1α is hallmark for hypoxia, correlating with poor prognosis and radio/chemotherapy resistance of primary-breast carcinoma. For bone metastasis, the molecular mechanisms involved in HIF-1α expression and HIF-1 (α/β heterodimer)-transcription factor activity are scarcely known. We studied the role played by HIF-1 in the cross-talk between neoplastic and supportive-microenvironmental cells. Also, WWdomain-containing oxidoreductase (Wwox) and transcriptional co-activator with PDZ-binding motif (TAZ) were taken into consideration evaluating whether these Hippo-pathway effectors affect bone-metastatic phenotype through HIF-1 activity. Considering bone-metastasis specimens, nuclear HIF-1α-TAZ co-localisation occurred in neoplastic and supportive cells, such as fibroblasts and endotheliocytes. Based on these data, the functional importance was verified using 1833-bone metastatic clone under hypoxia: nuclear HIF-1α and TAZ expression increased and co-immunoprecipitated, activating HIF-1-DNA binding and transactivation. In contrast, Wwox localised at perinuclear level in neoplastic cells of bone metastasis, being almost absent in supportive cells, and Wwox-protein expression diminished in hypoxic-1833 cells. Thus, TAZ regulation of HIF-1 activity might be important for bone-secondary growth, participating in metastasis-stroma cross-talk. Further, TAZ and HIF-1α-protein levels seemed correlated. In fact, blocking cyclooxygenase-2 with NS398 in hypoxic-1833 cells, not only HIF-1α decreased but also molecular-mechanism(s) upstream of the Hippo pathway were triggered: LATS-dependent TAZ phosphorylation seemed responsible for TAZ nucleus/cytoplasm translocation and degradation. In the 1833-xenograft model, NS398 largely prevented the outgrowth of bone-metastatic cells, probably related to remarkable-extracellular matrix assembly. We gained clinical insight into

  14. Effects of 17β-estradiol and 2-methoxyestradiol on the oxidative stress-hypoxia inducible factor-1 pathway in hypoxic pulmonary hypertensive rats.

    Science.gov (United States)

    Wang, Li; Zheng, Quan; Yuan, Yadong; Li, Yanpeng; Gong, Xiaowei

    2017-05-01

    The present study aimed to investigate the effects of 17β-estradiol (E2) and 2-methoxyestradiol (2ME) on the oxidative stress-hypoxia inducible factor-1 (OS-HIF-1) pathway in hypoxic pulmonary hypertensive rats. Female Sprague-Dawley rats were divided randomly into 4 groups, as follows: i) Control (Group A); ii) ovariectomy (OVX) + hypoxia (Group B); iii) OVX + hypoxia + E2 injection (Group C); and iv) 2ME injection (Group D). The rats were maintained under hypoxic conditions for 8 weeks, and mean pulmonary artery pressure (mPAP) and pulmonary arteriole morphology were measured. The reactive oxygen species, superoxide dismutase (SOD), manganese superoxide dismutase (MnSOD), and copper-zinc superoxide dismutase (Cu/ZnSOD) levels in serum were also measured. MnSOD and HIF-1α expression levels in lung tissue were determined by western blotting and reverse transcription-quantitative polymerase chain reaction. The mPAP and arterial remodeling index were significantly elevated following chronic hypoxia exposure; however, experimental data revealed a reduced response in E2 and 2ME intervention rats. Compared with Group A, Group B had significantly elevated oxidative stress levels, as illustrated by increased serum ROS levels, decreased serum SOD and MnSOD levels and decreased MnSOD mRNA and protein expression levels in lung tissue. Furthermore, HIF-1α mRNA and protein expression in Group B was significantly elevated compared with Group A. E2 and 2ME intervention significantly attenuated the aforementioned parameter changes, suggesting that E2 and 2ME partially ameliorate hypoxic pulmonary hypertension. The underlying mechanism of this may be associated with the increase in MnSOD activity and expression and reduction in ROS level, which reduces the levels of transcription and translation of HIF-1α.

  15. Hypoxia induces copper stable isotope fractionation in hepatocellular carcinoma, in a HIF-independent manner.

    Science.gov (United States)

    Bondanese, Victor P; Lamboux, Aline; Simon, Melanie; Lafont, Jérôme E; Albalat, Emmanuelle; Pichat, Sylvain; Vanacker, Jean-Marc; Telouk, Philippe; Balter, Vincent; Oger, Philippe; Albarède, Francis

    2016-11-09

    Hepatocellular carcinoma (HCC) is the most frequent type of primary liver cancer, with increasing incidence worldwide. The unrestrained proliferation of tumour cells leads to tumour hypoxia which in turn promotes cancer aggressiveness. While changes in the concentration of copper (Cu) have long been observed upon cancerization, we have recently reported that the isotopic composition of copper is also altered in several types of cancer. In particular, we showed that in hepatocellular carcinoma, tumour tissue contains heavier copper compared to the surrounding parenchyma. However, the reasons behind such isotopic signature remained elusive. Here we show that hypoxia causes heavy copper enrichment in several human cell lines. We also demonstrate that this effect of hypoxia is pH, HIF-1 and -2 independent. Our data identify a previously unrecognized cellular process associated with hypoxia, and suggests that in vivo tumour hypoxia determines copper isotope fractionation in HCC and other solid cancers.

  16. The accumulations of HIF-1α and HIF-2α by JNK and ERK are involved in biphasic effects induced by different levels of arsenite in human bronchial epithelial cells

    International Nuclear Information System (INIS)

    Xu, Yuan; Li, Yuan; Li, Huiqiao; Pang, Ying; Zhao, Yue; Jiang, Rongrong; Shen, Lu; Zhou, Jianwei; Wang, Xinru; Liu, Qizhan

    2013-01-01

    The biphasic effects of arsenite, in which low levels of arsenite induce cell proliferation and high levels of arsenite induce DNA damage and apoptosis, apparently contribute to arsenite-induced carcinogenesis. However, the mechanisms underlying this phenomenon are not well understood. In this study, we investigated the effects of different levels of arsenite on cell proliferation, DNA damage and apoptosis as well as on signal transduction pathways in human bronchial epithelial (HBE) cells. Our results show that a low level of arsenite activates extracellular signal-regulated kinases (ERK), which probably mediate arsenite-inhibited degradation of ubiquitinated hypoxia-inducible factor-2α (HIF-2α) in HBE cells. ERK inhibition blocks cell proliferation induced by a low level of arsenite, in part via HIF-2α. In contrast, a high level of arsenite activates c-Jun N-terminal kinases (JNK), which provoke a response to suppress ubiquitinated HIF-1α degradation. Down-regulation of HIF-1α by inhibiting JNK, however, increases the DNA damage but decreases the apoptosis induced by a high level of arsenite. Thus, data in the present study suggest that the accumulations of HIF-1α and HIF-2α by JNK and ERK are involved in different levels of arsenite-induced biphasic effects, with low levels of arsenite inducing cell proliferation and high levels of arsenite inducing DNA damage and apoptosis in HBE cells. -- Highlights: ► Biphasic effects induced by different concentrations of arsenite. ► Different regulation of ERK or JNK signal pathway by arsenite. ► Different regulation of HIF1α or HIF 2α by arsenite.

  17. High Nuclear Hypoxia-Inducible Factor 1 Alpha Expression Is a Predictor of Distant Recurrence in Patients With Resected Pancreatic Adenocarcinoma

    International Nuclear Information System (INIS)

    Colbert, Lauren E.; Fisher, Sarah B.; Balci, Serdar; Saka, Burcu; Chen, Zhengjia; Kim, Sungjin; El-Rayes, Bassel F.; Adsay, N. Volkan; Maithel, Shishir K.; Landry, Jerome C.

    2015-01-01

    Purpose: To evaluate nuclear hypoxia-inducible factor 1α (HIF-1α) expression as a prognostic factor for distant recurrence (DR) and local recurrence (LR) after pancreatic adenocarcinoma resection. Methods and Materials: Tissue specimens were collected from 98 patients with pancreatic adenocarcinoma who underwent resection without neoadjuvant therapy between January 2000 and December 2011. Local recurrence was defined as radiographic or pathologic evidence of progressive disease in the pancreas, pancreatic bed, or associated nodal regions. Distant recurrence was defined as radiographically or pathologically confirmed recurrent disease in other sites. Immunohistochemical staining was performed and scored by an independent pathologist blinded to patient outcomes. High HIF-1α overall expression score was defined as high percentage and intensity staining and thus score >1.33. Univariate analysis was performed for HIF-1α score with LR alone and with DR. Multivariate logistic regression was used to determine predictors of LR and DR. Results: Median follow-up time for all patients was 16.3 months. Eight patients (8%) demonstrated isolated LR, 26 patients (26.5%) had isolated DR, and 13 patients had both LR and DR. Fifty-three patients (54%) had high HIF-1α expression, and 45 patients (46%) had low HIF-1α expression. High HIF-1α expression was significantly associated with DR (P=.03), and low HIF-1α expression was significantly associated with isolated LR (P=.03). On multivariate logistic regression analysis, high HIF-1α was the only significant predictor of DR (odds ratio 2.46 [95% confidence interval 1.06-5.72]; P=.03). In patients with a known recurrence, an HIF-1α score ≥2.5 demonstrated a specificity of 100% for DR. Conclusions: High HIF-1α expression is a significant predictor of distant failure versus isolated local failure in patients undergoing resection of pancreatic adenocarcinoma. Expression of HIF-1α may have utility in determining candidates for

  18. Computational modeling on the recognition of the HRE motif by HIF-1: molecular docking and molecular dynamics studies.

    Science.gov (United States)

    Sokkar, Pandian; Sathis, Vani; Ramachandran, Murugesan

    2012-05-01

    Hypoxia inducible factor-1 (HIF-1) is a bHLH-family transcription factor that controls genes involved in glycolysis, angiogenesis, migration, as well as invasion factors that are important for tumor progression and metastasis. HIF-1, a heterodimer of HIF-1α and HIF-1β, binds to the hypoxia responsive element (HRE) present in the promoter regions of hypoxia responsive genes, such as vascular endothelial growth factor (VEGF). Neither the structure of free HIF-1 nor that of its complex with HRE is available. Computational modeling of the transcription factor-DNA complex has always been challenging due to their inherent flexibility and large conformational space. The present study aims to model the interaction between the DNA-binding domain of HIF-1 and HRE. Experiments showed that rigid macromolecular docking programs (HEX and GRAMM-X) failed to predict the optimal dimerization of individually modeled HIF-1 subunits. Hence, the HIF-1 heterodimer was modeled based on the phosphate system positive regulatory protein (PHO4) homodimer. The duplex VEGF-DNA segment containing HRE with flanking nucleotides was modeled in the B form and equilibrated via molecular dynamics (MD) simulation. A rigid docking approach was used to predict the crude binding mode of HIF-1 dimer with HRE, in which the putative contacts were found to be present. An MD simulation (5 ns) of the HIF-1-HRE complex in explicit water was performed to account for its flexibility and to optimize its interactions. All of the conserved amino acid residues were found to play roles in the recognition of HRE. The present work, which sheds light on the recognition of HRE by HIF-1, could be beneficial in the design of peptide or small molecule therapeutics that can mimic HIF-1 and bind with the HRE sequence.

  19. A New Hypoxia Inducible Factor-2 Inhibitory Pyrrolinone Alkaloid from Roots and Stems of Piper sarmentosum

    OpenAIRE

    BOKESCH, Heidi Rose; GARDELLA, Roberta Scott; RABE, Daniel Christopher; BOTTARO, Donald Paul; LINEHAN, William Marston; MCMAHON, James Brislin; MCKEE, Tawnya Carlene

    2011-01-01

    A new trimethoxycinnamoyl-2-pyrrolinone alkaloid, langkamide (1), along with the known compounds piplartine (2) and 3,4,5-trimethoxycinnamic acid (3) were isolated from the roots and stems of the shrub Piper sarmentosum Roxb. The structures were established by spectroscopic analyses and comparison of their spectral data with values reported in the literature. The compounds were tested for their ability to modulate hypoxia inducible factor-2 (HIF-2) transcription activity and all three showed ...

  20. Protective role of hypoxia-inducible factor-1α-dependent CD39 and CD73 in fulminant acute liver failure

    Energy Technology Data Exchange (ETDEWEB)

    Tak, Eunyoung [Asan Institute for Life Sciences and Asan-Minnesota Institute for Innovating Transplantation, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Jung, Dong-Hwan; Kim, Seok-Hwan; Park, Gil-Chun [Division of Liver Transplantation and Hepatobiliary Surgery, Asan-Minnesota Institute for Innovating Transplantation, Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Jun, Dae Young; Lee, Jooyoung [Asan Institute for Life Sciences and Asan-Minnesota Institute for Innovating Transplantation, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Jung, Bo-hyun [Department of Surgery, Inje University Haeundae Paik Hospital, Inje University College of Medicine, Busan (Korea, Republic of); Kirchner, Varvara A. [Division of Transplantation, Department of Surgery and Asan-Minnesota Institute for Innovating Transplantation, University of Minnesota, Minneapolis, MN (United States); Hwang, Shin [Division of Liver Transplantation and Hepatobiliary Surgery, Asan-Minnesota Institute for Innovating Transplantation, Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Song, Gi-Won, E-mail: drsong71@amc.seoul.kr [Division of Liver Transplantation and Hepatobiliary Surgery, Asan-Minnesota Institute for Innovating Transplantation, Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Lee, Sung-Gyu [Division of Liver Transplantation and Hepatobiliary Surgery, Asan-Minnesota Institute for Innovating Transplantation, Department of Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2017-01-01

    Acute liver failure (ALF) is a severe life-threatening disease which usually arises in patients with-irreversible liver illnesses. Although human ectonucleotide triphosphate diphosphohydrolase-1, E-NTPDase1 (CD39) and ecto-5′-nucleotidase, Ecto5′NTase (CD73) are known to protect tissues from ALF, the expression and function of CD39 and CD73 during ALF are currently not fully investigated. We tested whether CD39 and CD73 are upregulated by hypoxia inducible factor (HIF)-1α, and improve ischemic tolerance to ALF. To test our hypothesis, liver biopsies were obtained and we found that CD39 and CD73 mRNA and proteins from human specimens were dramatically elevated in ALF. We investigated that induction of CD39 and CD73 in ALF-related with wild type mice. In contrast, deletion of cd39 and cd73 mice has severe ALF. In this study, we concluded that CD39 and CD73 are molecular targets for the development of drugs for ALF patients care. - Highlights: • HIF-1a is stabilized during acute liver failure • Upregulation of CD39 and CD73 following acute liver failure • CD39 and CD73 are transcriptionally induced by HIF-1a • Deletion of Cd39 and CD73 aggravates murine acute liver failure • DMOG treatment induces HIF-1a stabilization, CD39 and CD73 during acute liver failure in WT mice.

  1. Hypoxia-Inducible Factor and Its Role in the Management of Anemia in Chronic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Joshua M. Kaplan

    2018-01-01

    Full Text Available Hypoxia-inducible factor (HIF plays a crucial role in the response to hypoxia at the cellular, tissue, and organism level. New agents under development to pharmacologically manipulate HIF may provide new and exciting possibilities in the treatment of anemia of chronic kidney disease (CKD as well as in multiple other disease states involving ischemia–reperfusion injury. This article provides an overview of recent studies describing current standards of care for patients with anemia in CKD and associated clinical issues, and those supporting the clinical potential for targeting HIF stabilization with HIF prolyl-hydroxylase inhibitors (HIF-PHI in these patients. Additionally, articles reporting the clinical potential for HIF-PHIs in ‘other’ putative therapeutic areas, the tissue and intracellular distribution of HIF- and prolyl-hydroxylase domain (PHD isoforms, and HIF isoforms targeted by the different PHDs, were identified. There is increasing uncertainty regarding the optimal treatment for anemia of CKD with poorer outcomes associated with treatment to higher hemoglobin targets, and the increasing use of iron and consequent risk of iron imbalance. Attainment and maintenance of more physiologic erythropoietin levels associated with HIF stabilization may improve the management of patients resistant to treatment with erythropoiesis-stimulating agents and improve outcomes at higher hemoglobin targets.

  2. Hypoxia-Inducible Histone Lysine Demethylases: Impact on the Aging Process and Age-Related Diseases

    Science.gov (United States)

    Salminen, Antero; Kaarniranta, Kai; Kauppinen, Anu

    2016-01-01

    Hypoxia is an environmental stress at high altitude and underground conditions but it is also present in many chronic age-related diseases, where blood flow into tissues is impaired. The oxygen-sensing system stimulates gene expression protecting tissues against hypoxic insults. Hypoxia stabilizes the expression of hypoxia-inducible transcription factor-1α (HIF-1α), which controls the expression of hundreds of survival genes related to e.g. enhanced energy metabolism and autophagy. Moreover, many stress-related signaling mechanisms, such as oxidative stress and energy metabolic disturbances, as well as the signaling cascades via ceramide, mTOR, NF-κB, and TGF-β pathways, can also induce the expression of HIF-1α protein to facilitate cell survival in normoxia. Hypoxia is linked to prominent epigenetic changes in chromatin landscape. Screening studies have indicated that the stabilization of HIF-1α increases the expression of distinct histone lysine demethylases (KDM). HIF-1α stimulates the expression of KDM3A, KDM4B, KDM4C, and KDM6B, which enhance gene transcription by demethylating H3K9 and H3K27 sites (repressive epigenetic marks). In addition, HIF-1α induces the expression of KDM2B and KDM5B, which repress transcription by demethylating H3K4me2,3 sites (activating marks). Hypoxia-inducible KDMs support locally the gene transcription induced by HIF-1α, although they can also control genome-wide chromatin landscape, especially KDMs which demethylate H3K9 and H3K27 sites. These epigenetic marks have important role in the control of heterochromatin segments and 3D folding of chromosomes, as well as the genetic loci regulating cell type commitment, proliferation, and cellular senescence, e.g. the INK4 box. A chronic stimulation of HIF-1α can provoke tissue fibrosis and cellular senescence, which both are increasingly present with aging and age-related diseases. We will review the regulation of HIF-1α-dependent induction of KDMs and clarify their role in

  3. SDF-1 alpha expression during wound healing in the aged is HIF dependent.

    Science.gov (United States)

    Loh, Shang A; Chang, Edward I; Galvez, Michael G; Thangarajah, Hariharan; El-ftesi, Samyra; Vial, Ivan N; Lin, Darius A; Gurtner, Geoffrey C

    2009-02-01

    Age-related impairments in wound healing are associated with decreased neovascularization, a process that is regulated by hypoxia-responsive cytokines, including stromal cell-derived factor (SDF)-1 alpha. Interleukin-1 beta is an important inflammatory cytokine involved in wound healing and is believed to regulate SDF-1 alpha expression independent of hypoxia signaling. Thus, the authors examined the relative importance of interleukin (IL)-1 beta and hypoxia-inducible factor (HIF)-1 alpha on SDF-1 alpha expression in aged wound healing. Young and aged mice (n = 4 per group) were examined for wound healing using a murine excisional wound model. Wounds were harvested at days 0, 1, 3, 5, and 7 for histologic analysis, immunohistochemistry, enzyme-linked immunosorbent assay, and Western blot. An engineered wild-type and mutated SDF luciferase reporter construct were used to determine HIF transactivation. Aged mice demonstrated significantly impaired wound healing, reduced granulation tissue, and increased epithelial gap compared with young controls. Real-time polymerase chain reaction demonstrated reduced SDF-1 alpha levels in aged wounds that correlated with reduced CD31+ neovessels. Western blots revealed decreased HIF-1 alpha protein in aged wounds. However, both IL-1 beta and macrophage infiltrate were unchanged between young and aged animals. Using the wild-type and mutated SDF luciferase reporter construct in which the hypoxia response element was deleted, only young fibroblasts were able to respond to IL-1 beta stimulation, and this response was abrogated by mutating the HIF-binding sites. This suggests that HIF binding is essential for SDF-1 transactivation in response to both inflammatory and hypoxic stimuli. SDF-1 alpha deficiency observed during aged wound healing is attributable predominantly to decreased HIF-1 alpha levels rather than impaired IL-1 beta expression.

  4. Hypoxic inactivation of glycogen synthase kinase-3β promotes gastric tumor growth and angiogenesis by facilitating hypoxia-inducible factor-1 signaling.

    Science.gov (United States)

    Ko, Young San; Cho, Sung Jin; Park, Jinju; Choi, Yiseul; Lee, Jae-Seon; Youn, Hong-Duk; Kim, Woo Ho; Kim, Min A; Park, Jong-Wan; Lee, Byung Lan

    2016-09-01

    Since the molecular mechanism of hypoxic adaptation in cancer cells is cell-type specific, we investigated whether glycogen synthase kinase-3β (GSK-3β) activation is involved in hypoxia-induced gastric tumor promotion. Stable gastric cancer cell lines (SNU-638, SNU-484, MKN1, and MKN45) were cultured under hypoxic conditions. Cells overexpressing wild-type GSK-3β (WT-GSK-3β) or kinase-dead mutant of GSK-3β (KD-GSK-3β) were generated and used for cell culture and animal studies. In cell culture experiments, hypoxia decreased GSK-3β activation in gastric cancer cells. Cell viability and the expressions of HIF-1α protein and VEGF mRNA in gastric cancer cells were higher in KD-GSK-3β transfectants than in WT-GSK-3β transfectants under hypoxic conditions, but not under normoxic conditions. Gastric cancer xenografts showed that tumor growth, microvessel area, HIF-1α activation, and VEGF expression were higher in KD-GSK-3β tumors than in WT-GSK-3β tumors in vivo. In addition, the expression of hypoxia-induced HIF-1α protein was regulated by GSK-3β at the translational level. Our data suggest that GSK-3β is involved in hypoxic adaptation of gastric cancer cells as an inhibitory upstream regulator of the HIF-1α/VEGF signaling pathway. © 2016 APMIS. Published by John Wiley & Sons Ltd.

  5. Interleukin-17 limits hypoxia-inducible factor 1α and development of hypoxic granulomas during tuberculosis.

    Science.gov (United States)

    Domingo-Gonzalez, Racquel; Das, Shibali; Griffiths, Kristin L; Ahmed, Mushtaq; Bambouskova, Monika; Gopal, Radha; Gondi, Suhas; Muñoz-Torrico, Marcela; Salazar-Lezama, Miguel A; Cruz-Lagunas, Alfredo; Jiménez-Álvarez, Luis; Ramirez-Martinez, Gustavo; Espinosa-Soto, Ramón; Sultana, Tamanna; Lyons-Weiler, James; Reinhart, Todd A; Arcos, Jesus; de la Luz Garcia-Hernandez, Maria; Mastrangelo, Michael A; Al-Hammadi, Noor; Townsend, Reid; Balada-Llasat, Joan-Miquel; Torrelles, Jordi B; Kaplan, Gilla; Horne, William; Kolls, Jay K; Artyomov, Maxim N; Rangel-Moreno, Javier; Zúñiga, Joaquín; Khader, Shabaana A

    2017-10-05

    Mycobacterium tuberculosis (Mtb) is a global health threat, compounded by the emergence of drug-resistant strains. A hallmark of pulmonary tuberculosis (TB) is the formation of hypoxic necrotic granulomas, which upon disintegration, release infectious Mtb. Furthermore, hypoxic necrotic granulomas are associated with increased disease severity and provide a niche for drug-resistant Mtb. However, the host immune responses that promote the development of hypoxic TB granulomas are not well described. Using a necrotic Mtb mouse model, we show that loss of Mtb virulence factors, such as phenolic glycolipids, decreases the production of the proinflammatory cytokine IL-17 (also referred to as IL-17A). IL-17 production negatively regulates the development of hypoxic TB granulomas by limiting the expression of the transcription factor hypoxia-inducible factor 1α (HIF1α). In human TB patients, HIF1α mRNA expression is increased. Through genotyping and association analyses in human samples, we identified a link between the single nucleotide polymorphism rs2275913 in the IL-17 promoter (-197G/G), which is associated with decreased IL-17 production upon stimulation with Mtb cell wall. Together, our data highlight a potentially novel role for IL-17 in limiting the development of hypoxic necrotic granulomas and reducing disease severity in TB.

  6. Wogonin inhibits tumor angiogenesis via degradation of HIF-1α protein

    International Nuclear Information System (INIS)

    Song, Xiuming; Yao, Jing; Wang, Fei; Zhou, Mi; Zhou, Yuxin; Wang, Hu; Wei, Libin; Zhao, Li; Li, Zhiyu; Lu, Na; Guo, Qinglong

    2013-01-01

    Wogonin, a plant-derived flavone, has been shown recently to have antitumor effects. However, the mechanisms that wogonin inhibits tumor angiogenesis are not well known. In this study, we investigated the effects of wogonin on expression of hypoxia-inducible factor-1α (HIF-1α) and secretion of vascular endothelial growth factor (VEGF) in tumor cells. We found that wogonin decreased the expression of HIF-1α by affecting its stability and reduced the secretion of VEGF, which suppressed angiogenesis in cancer. Wogonin promoted the degradation of HIF-1α by increasing its prolyl hydroxylation, which depended on prolyl hydroxylase (PHD) and the von Hippel–Lindau tumor suppressor (VHL). Intriguingly, wogonin impeded the binding between heat-shock protein 90 (Hsp90) and HIF-1α. In addition, wogonin down-regulated the Hsp90 client proteins EGFR, Cdk4 and survivin, but did not affect the level of Hsp90. Wogonin also increased ubiquitination of HIF-1α and promoted its degradation in proteasome. We also found that wogonin could inhibit nuclear translocation of HIF-1α. Electrophoresis mobility shift assay (EMSA) showed that wogonin decreased the binding activity of exogenous consensus DNA oligonucleotide with HIF-1α in nuclear extracts from MCF-7 cells. Chromatin immunoprecipitation (ChIP) assay also revealed that HIF-1α directly binded to endogenous hypoxia-responsive element (HRE) and this binding was significantly decreased in MCF-7 cells treated with wogonin. Preliminary results indicated in vivo activity of wogonin against xenograft-induced angiogenesis in nude mice. Taken together, the results suggested that wogonin was a potent inhibitor of HIF-1α and provided a new insight into the mechanisms of wogonin against cancers. - Highlights: • Wogonin is an all around inhibitor of VEGF signaling. • We firstly demonstrate that wogonin inhibits secretion of VEGF by decreasing HIF-1α. • Wogonin enhances PDH and VHL expression and inhibits Hsp90 function.

  7. Wogonin inhibits tumor angiogenesis via degradation of HIF-1α protein

    Energy Technology Data Exchange (ETDEWEB)

    Song, Xiuming; Yao, Jing; Wang, Fei; Zhou, Mi; Zhou, Yuxin; Wang, Hu; Wei, Libin; Zhao, Li; Li, Zhiyu; Lu, Na, E-mail: luna555@163.com; Guo, Qinglong, E-mail: anticancer_drug@yahoo.com.cn

    2013-09-01

    Wogonin, a plant-derived flavone, has been shown recently to have antitumor effects. However, the mechanisms that wogonin inhibits tumor angiogenesis are not well known. In this study, we investigated the effects of wogonin on expression of hypoxia-inducible factor-1α (HIF-1α) and secretion of vascular endothelial growth factor (VEGF) in tumor cells. We found that wogonin decreased the expression of HIF-1α by affecting its stability and reduced the secretion of VEGF, which suppressed angiogenesis in cancer. Wogonin promoted the degradation of HIF-1α by increasing its prolyl hydroxylation, which depended on prolyl hydroxylase (PHD) and the von Hippel–Lindau tumor suppressor (VHL). Intriguingly, wogonin impeded the binding between heat-shock protein 90 (Hsp90) and HIF-1α. In addition, wogonin down-regulated the Hsp90 client proteins EGFR, Cdk4 and survivin, but did not affect the level of Hsp90. Wogonin also increased ubiquitination of HIF-1α and promoted its degradation in proteasome. We also found that wogonin could inhibit nuclear translocation of HIF-1α. Electrophoresis mobility shift assay (EMSA) showed that wogonin decreased the binding activity of exogenous consensus DNA oligonucleotide with HIF-1α in nuclear extracts from MCF-7 cells. Chromatin immunoprecipitation (ChIP) assay also revealed that HIF-1α directly binded to endogenous hypoxia-responsive element (HRE) and this binding was significantly decreased in MCF-7 cells treated with wogonin. Preliminary results indicated in vivo activity of wogonin against xenograft-induced angiogenesis in nude mice. Taken together, the results suggested that wogonin was a potent inhibitor of HIF-1α and provided a new insight into the mechanisms of wogonin against cancers. - Highlights: • Wogonin is an all around inhibitor of VEGF signaling. • We firstly demonstrate that wogonin inhibits secretion of VEGF by decreasing HIF-1α. • Wogonin enhances PDH and VHL expression and inhibits Hsp90 function.

  8. The interplay between HIF-1 and calcium signalling in cancer.

    Science.gov (United States)

    Azimi, Iman

    2018-04-01

    The interplay between hypoxia-inducible factor-1 (HIF-1) and calcium in cancer has begun to be unravelled with recent findings demonstrating the relationships between the two in different cancer types. This is an area of significance considering the crucial roles of both HIF-1 and calcium signalling in cancer progression and metastasis. This review summarises the experimental evidence of the crosstalk between HIF-1 and specific calcium channels, pumps and regulators in the context of cancer. HIF-1 as a master regulator of hypoxic transcriptional responses, mediates transcription of several calcium modulators. On the other hand, specific calcium channels and pumps regulate HIF-1 activity through controlling its transcription, translation, stabilisation, or nuclear translocation. Identifying the interplay between HIF-1 and components of the calcium signal will give new insights into mechanisms underlying cellular responses to physiological and pathophysiological cues, and may provide novel and more efficient therapeutic strategies for the control of cancer progression. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. [The effect of hypoxia preconditioning no binding activity of HIF-1 on the HRE with EPO in the hippocampus of mice].

    Science.gov (United States)

    Shao, Guo; Zhou, Wei-Hua; Gao, Cui-Ying; Zhang, Ran; Lu, Guo-Wei

    2007-02-01

    To observe change of binding activity of HIF-1 with erythropoietin (EPO) hypoxia response element (HRE) in the hippocampus of mice preconditioned to hypoxia and explore relationship between the changes and the preconditioning. The hippocampus was removed from mice exposed to hypoxia for 0 run (control group), 1 run (H1 group) and 4 runs(H4 group). Electrophoretic mobility shift assays (EMSA), chromatin immunoprecipitation (ChIP)and real time PCR were used to detect the change of activity of HIF-1 on HRE of EPO. Both in vitro and in vivo binding tests showed that the HIF-1 DNA-binding activities were increased in group H1 and markedly increased in group H4. The increase of HIF-1 and HRE of EPO binding activities is thought be involved in hypoxic preconditioning.

  10. PACAP and VIP inhibit the invasiveness of glioblastoma cells exposed to hypoxia through the regulation of HIFs and EGFR expression

    Directory of Open Access Journals (Sweden)

    Grazia eMaugeri

    2016-05-01

    Full Text Available Pituitary adenylate cyclase-activating polypeptide (PACAP and vasoactive intestinal peptide (VIP through the binding of vasoactive intestinal peptide receptors (VIPRs, perform a wide variety of effects in human cancers, including glioblastoma multiforme (GBM. This tumor is characterized by extensive areas of hypoxia, which triggers the expression of hypoxia-inducible factors (HIFs. HIFs not only mediate angiogenesis but also tumor cell migration and invasion. Furthermore, HIFs activation is linked to epidermal growth factor receptor (EGFR overexpression. Previous studies have shown that VIP interferes with the invasive nature of gliomas by regulating cell migration. However, the role of VIP family members in GBM infiltration under low oxygen tension has not been clarified yet. Therefore, in the present study we have investigated, for the first time, the molecular mechanisms involved in the anti-invasive effect of PACAP or VIP in U87MG glioblastoma cells exposed to hypoxia induced by treatment with desferrioxamine (DFX. The results suggest that either PACAP or VIP exert an anti-infiltrative effect under low oxygen tension by modulating HIFs and EGFR expression, key elements involved in cell migration and angiogenesis. These peptides act through the inhibition of PI3K/Akt and MAPK/ERK signaling pathways, which are known to have a crucial role in HIFs regulation. In conclusion, the modulation of hypoxic event and the anti-invasive effect exerted by some VIP family members might open new insights in the therapeutic approach to GBM.

  11. HIF1-alpha overexpression indicates a good prognosis in early stage squamous cell carcinomas of the oral floor

    International Nuclear Information System (INIS)

    Fillies, Thomas; Werkmeister, Richard; Diest, Paul J van; Brandt, Burkhard; Joos, Ulrich; Buerger, Horst

    2005-01-01

    Hypoxia-inducible factor 1 (HIF-1) is a transcription factor, which plays a central role in biologic processes under hypoxic conditions, especially concerning tumour angiogenesis. HIF-1α is the relevant, oxygen-dependent subunit and its overexpression has been associated with a poor prognosis in a variety of malignant tumours. Therefore, HIF-1α expression in early stage oral carcinomas was evaluated in relation to established clinico-pathological features in order to determine its value as a prognostic marker. 85 patients with histologically proven surgically treated T1/2 squamous cell carcinoma (SCC) of the oral floor were eligible for the study. Tumor specimens were investigated by means of tissue micro arrays (TMAs) and immunohistochemistry for the expression of HIF-1. Correlations between clinical features and the expression of HIF-1 were evaluated by Kaplan-Meier curves, log-rank tests and multivariate Cox regression analysis. HIF-1α was frequently overexpressed in a probably non-hypoxia related fashion. The expression of HIF-1α was related with a significantly improved 5-year survival rate (p < 0.01) and a significantly increased disease free period (p = 0.01) independent from nodal status and tumour size. In primary node negative T1/T2 SCC of the oral floor, absence of HIF-1α expression specified a subgroup of high-risk patients (p < 0.05). HIF-1α overexpression is an indicator of favourable prognosis in T1 and T2 SCC of the oral floor. Node negative patients lacking HIF-1α expression may therefore be considered for adjuvant radiotherapy

  12. Ascofuranone suppresses EGF-induced HIF-1α protein synthesis by inhibition of the Akt/mTOR/p70S6K pathway in MDA-MB-231 breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Yun-Jeong; Cho, Hyun-Ji [Research Institute of Biomedical Engineering and Department of Medicine, Catholic University of Daegu School of Medicine, Daegu 705-718 (Korea, Republic of); Magae, Junji [Magae Bioscience Institute, 49-4 Fujimidai, Tsukuba 300-1263 (Japan); Lee, In-Kyu [Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu 700-721 (Korea, Republic of); Park, Keun-Gyu, E-mail: kpark@knu.ac.kr [Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu 700-721 (Korea, Republic of); Chang, Young-Chae, E-mail: ycchang@cu.ac.kr [Research Institute of Biomedical Engineering and Department of Medicine, Catholic University of Daegu School of Medicine, Daegu 705-718 (Korea, Republic of)

    2013-12-15

    Hypoxia-inducible factor (HIF)-1 plays an important role in tumor progression, angiogenesis and metastasis. In this study, we investigated the potential molecular mechanisms underlying the anti-angiogenic effect of ascofuranone, an isoprenoid antibiotic from Ascochyta viciae, in epidermal growth factor (EGF)-1 responsive human breast cancer cells. Ascofuranone significantly and selectively suppressed EGF-induced HIF-1α protein accumulation, whereas it did not affect the expression of HIF-1β. Furthermore, ascofuranone inhibited the transcriptional activation of vascular endothelial growth factor (VEGF) by reducing protein HIF-1α. Mechanistically, we found that the inhibitory effects of ascofuranone on HIF-1α protein expression are associated with the inhibition of synthesis HIF-1α through an EGF-dependent mechanism. In addition, ascofuranone suppressed EGF-induced phosphorylation of Akt/mTOR/p70S6 kinase, but the phosphorylation of ERK/JNK/p38 kinase was not affected by ascofuranone. These results suggest that ascofuranone suppresses EGF-induced HIF-1α protein translation through the inhibition of Akt/mTOR/p70S6 kinase signaling pathways and plays a novel role in the anti-angiogenic action. - Highlights: • Inhibitory effect of ascofuranone on HIF-1α expression is EGF-specific regulation. • Ascofuranone decreases HIF-1α protein synthesis through Akt/mTOR pathways. • Ascofuranone suppresses EGF-induced VEGF production and tumor angiogenesis.

  13. Insights into the therapeutic potential of hypoxia-inducible factor-1α small interfering RNA in malignant melanoma delivered via folate-decorated cationic liposomes

    Directory of Open Access Journals (Sweden)

    Chen Z

    2016-03-01

    Full Text Available Zhongjian Chen,1,* Tianpeng Zhang,2,* Baojian Wu,2 Xingwang Zhang2 1Department of Pharmaceutics, Shanghai Dermatology Hospital, 2Division of Pharmaceutics, College of Pharmacy, Jinan University, Gangzhou, People’s Republic of China *These authors contributed equally to this work Abstract: Malignant melanoma (MM represents the most dangerous form of skin cancer, and its incidence is expected to rise in the coming time. However, therapy for MM is limited by low topical drug concentration and multidrug resistance. This article aimed to develop folate-decorated cationic liposomes (fc-LPs for hypoxia-inducible factor-1α (HIF-1α small interfering (siRNA delivery, and to evaluate the potential of such siRNA/liposome complexes in MM therapy. HIF-1α siRNA-loaded fc-LPs (siRNA-fc-LPs were prepared by a film hydration method followed by siRNA incubation. Folate decoration of liposomes was achieved by incorporation of folate/oleic acid-diacylated oligochitosans. The resulting siRNA-fc-LPs were 95.3 nm in size with a ζ potential of 2.41 mV. The liposomal vectors exhibited excellent loading capacity and protective effect toward siRNA. The in vitro cell transfection efficiency was almost parallel to the commercially available Lipofectamine™ 2000. Moreover, the anti-melanoma activity of HIF-1α siRNA was significantly enhanced through fc-LPs. Western blot analysis and apoptosis test demonstrated that siRNA-fc-LPs substantially reduced the production of HIF-1α-associated protein and induced the apoptosis of hypoxia-tolerant melanoma cells. Our designed liposomal vectors might be applicable as siRNA delivery vehicle to systemically or topically treat MM. Keywords: malignant melanoma, HIF-1α siRNA, chitosan, cationic liposomes, gene therapy

  14. Increased tumour ascorbate is associated with extended disease-free survival and decreased hypoxia-inducible factor-1 activation in human colorectal cancer

    Directory of Open Access Journals (Sweden)

    Caroline eKuiper

    2014-02-01

    Full Text Available Ascorbate is a co-factor for the hydroxylases that regulate the transcription factor hypoxia-inducible factor (HIF-1, which provides cancer cells with a metabolic and survival advantage in the hypoxic environment of solid tumors. However, whether ascorbate affects tumor development is a highly debated issue. We aimed to determine whether tumor ascorbate was associated with HIF-1 activation and patient disease-free survival. In this study we undertook a retrospective observational analysis of tissue-banked tumor and paired normal tissue from 49 colorectal cancer patients, measuring ascorbate levels, HIF-1α and its downstream gene products BNIP3 and VEGF. Patient survival was monitored for the first six years after surgery. We found that ascorbate levels were lower in tumor tissue compared to normal tissue (p< 0.001 but overall levels varied considerably. HIF-1α, VEGF and BNIP3 were elevated in tumor samples (p< 0.01. There was an inverse relationship between tumor ascorbate content and HIF-1 pathway activation (p=0.002 and tumor size (p=0.018. Higher tumor ascorbate content was associated with significantly improved disease-free survival in the first 6 years after surgery (p=0.006, with 141 - 1,094 additional disease free days. This was independent of tumor grade and stage. Survival advantage was associated with the amount of ascorbate in the tumor, but not with the amount in adjacent normal tissue. Our results demonstrate that higher tumor ascorbate content is associated decreased HIF-1 activation, most likely due to the co-factor activity of ascorbate for the regulatory HIF hydroxylases. Our findings support the need for future studies to determine whether raising tumor ascorbate is possible with clinical intervention and whether this results in modification of hydroxylase-dependent pathways in the tumor.

  15. D-Glucosamine down-regulates HIF-1{alpha} through inhibition of protein translation in DU145 prostate cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jee-Young; Park, Jong-Wook; Suh, Seong-Il [Chronic Disease Research Center, School of Medicine, Keimyung University, 194 Dongsan-Dong, Jung-Gu, Daegu 700-712 (Korea, Republic of); Baek, Won-Ki, E-mail: wonki@dsmc.or.kr [Chronic Disease Research Center, School of Medicine, Keimyung University, 194 Dongsan-Dong, Jung-Gu, Daegu 700-712 (Korea, Republic of)

    2009-04-24

    D-Glucosamine has been reported to inhibit proliferation of cancer cells in culture and in vivo. In this study we report a novel response to D-glucosamine involving the translation regulation of hypoxia inducible factor (HIF)-1{alpha} expression. D-Glucosamine caused a decreased expression of HIF-1{alpha} under normoxic and hypoxic conditions without affecting HIF-1{alpha} mRNA expression in DU145 prostate cancer cells. D-Glucosamine inhibited HIF-1{alpha} accumulation induced by proteasome inhibitor MG132 and prolyl hydroxylase inhibitor DMOG suggesting D-glucosamine reduces HIF-1{alpha} protein expression through proteasome-independent pathway. Metabolic labeling assays indicated that D-glucosamine inhibits translation of HIF-1{alpha} protein. In addition, D-glucosamine inhibited HIF-1{alpha} expression induced by serum stimulation in parallel with inhibition of p70S6K suggesting D-glucosamine inhibits growth factor-induced HIF-1{alpha} expression, at least in part, through p70S6K inhibition. Taken together, these results suggest that D-glucosamine inhibits HIF-1{alpha} expression through inhibiting protein translation and provide new insight into a potential mechanism of the anticancer properties of D-glucosamine.

  16. IL-1β upregulates Muc5ac expression via NF-κB-induced HIF-1α in asthma.

    Science.gov (United States)

    Wu, Shouzhen; Li, Hailong; Yu, Lijuan; Wang, Ning; Li, Xu; Chen, Wei

    2017-12-01

    The manifest and important feature in respiratory diseases, including asthma and COPD (chronic obstructive pulmonary disease), is the increased numbers and hypersecretion of goblet cells and overexpression of mucins, especially Muc5ac. Many proinflammatory cytokines play important roles in goblet cell metaplasia and overproduction of Muc5ac. However, the effect of IL-1β on Muc5ac expression in asthma remains unknown. Here, we detected the correlation between IL-1β and Muc5ac in asthma patients and further explored the mechanism of IL-1β-induced Muc5ac overexpression. Our results showed that Muc5ac and IL-1β were up-regulated in 41 patients with asthma and that Muc5ac overexpression was related with IL-1β in asthma (R 2 =0.668, p≪0.001). Furthermore, the correlation between IL-1β and Muc5ac is higher in severe group than that in moderate group. In vitro experiments with normal human bronchial epithelial cells (NHBECs) showed that IL-1β up-regulated Muc5ac expression in NHBEC in a time- and dosage-dependent manner. Hypoxia-induced HIF-1α was responsible for Muc5ac expression mediated by IL-1β. Knocking down HIF-1α by siRNA decreased Muc5ac expression under hypoxia even in IL-1β-treated NHBEC cells. Luciferase reporter assay showed that HIF-1α enhanced Muc5ac promoter activity in HEK293T cells. HIF-1α could specifically bind to the promoter of Muc5ac by EMSA. The correlation among IL-1β, HIF-1α and Muc5ac was observed in patients with asthma. Mechanically, NF-κB activation was essential to IL-1β-induced HIF-1α upregulation via the canonical pathway of NF-κB. The level of nuclear p65, a subunit of NF-κB, was obviously increased in NHBEC cells under IL-1β treatment. IL-1β did not change either HIF-1α or Muc5ac expression when inhibiting NF-κB signaling with Bay11-7082, an inhibitor of NF-κB. Collectively, we concluded that IL-1β up-regulated Muc5ac expression via NF-κB-induced HIF-1α in asthma and provided a potential therapeutic target for

  17. Copper Deficiency Leads to Anemia, Duodenal Hypoxia, Upregulation of HIF-2α and Altered Expression of Iron Absorption Genes in Mice

    Science.gov (United States)

    Matak, Pavle; Zumerle, Sara; Mastrogiannaki, Maria; El Balkhi, Souleiman; Delga, Stephanie; Mathieu, Jacques R. R.; Canonne-Hergaux, François; Poupon, Joel; Sharp, Paul A.; Vaulont, Sophie; Peyssonnaux, Carole

    2013-01-01

    Iron and copper are essential trace metals, actively absorbed from the proximal gut in a regulated fashion. Depletion of either metal can lead to anemia. In the gut, copper deficiency can affect iron absorption through modulating the activity of hephaestin - a multi-copper oxidase required for optimal iron export from enterocytes. How systemic copper status regulates iron absorption is unknown. Mice were subjected to a nutritional copper deficiency-induced anemia regime from birth and injected with copper sulphate intraperitoneally to correct the anemia. Copper deficiency resulted in anemia, increased duodenal hypoxia and Hypoxia inducible factor 2α (HIF-2α) levels, a regulator of iron absorption. HIF-2α upregulation in copper deficiency appeared to be independent of duodenal iron or copper levels and correlated with the expression of iron transporters (Ferroportin - Fpn, Divalent Metal transporter – Dmt1) and ferric reductase – Dcytb. Alleviation of copper-dependent anemia with intraperitoneal copper injection resulted in down regulation of HIF-2α-regulated iron absorption genes in the gut. Our work identifies HIF-2α as an important regulator of iron transport machinery in copper deficiency. PMID:23555700

  18. Prolonged fasting activates hypoxia inducible factors-1α, -2α and -3α in a tissue-specific manner in northern elephant seal pups.

    Science.gov (United States)

    Soñanez-Organis, José G; Vázquez-Medina, José P; Crocker, Daniel E; Ortiz, Rudy M

    2013-09-10

    Hypoxia inducible factors (HIFs) are important regulators of energy homeostasis and cellular adaptation to low oxygen conditions. Northern elephant seals are naturally adapted to prolonged periods (1-2 months) of food deprivation (fasting) which result in metabolic changes that may activate HIF-1. However, the effects of prolonged fasting on HIFs are not well defined. We obtained the full-length cDNAs of HIF-1α and HIF-2α, and partial cDNA of HIF-3α in northern elephant seal pups. We also measured mRNA and nuclear protein content of HIF-1α, -2α, -3α in muscle and adipose during prolonged fasting (1, 3, 5 & 7 weeks), along with mRNA expression of HIF-mediated genes, LDH and VEGF. HIF-1α, -2α and -3α are 2595, 2852 and 1842 bp and encode proteins of 823, 864 and 586 amino acid residues with conserved domains needed for their function (bHLH and PAS) and regulation (ODD and TAD). HIF-1α and -2α mRNA expression increased 3- to 5-fold after 7 weeks of fasting in adipose and muscle, whereas HIF-3α increased 5-fold after 7 weeks of fasting in adipose. HIF-2α protein expression was detected in nuclear fractions from adipose and muscle, increasing approximately 2-fold, respectively with fasting. Expression of VEGF increased 3-fold after 7 weeks in adipose and muscle, whereas LDH mRNA expression increased 12-fold after 7 weeks in adipose. While the 3 HIFα genes are expressed in muscle and adipose, only HIF-2α protein was detectable in the nucleus suggesting that HIF-2α may contribute more significantly in the up-regulation of genes involved in the metabolic adaptation during fasting in the elephant seal. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Hypoxia-inducible factor-1α mediates the toll-like receptor 4 signaling pathway leading to anti-tumor effects in human hepatocellular carcinoma cells under hypoxic conditions.

    Science.gov (United States)

    Zhang, Xiaoyu; Li, Shuchen; Li, Mingrong; Huang, Haiying; Li, Jingyuan; Zhou, Changwei

    2016-08-01

    Hypoxia-inducible factor-1α (HIF-1α) and toll-like receptor 4 (TLR4) are involved in numerous mechanisms of cancer biology, including cell proliferation and survival; however the interaction of the two factors under hypoxic conditions remains unclear. The present study investigated the in vitro mechanism that results in the suppression of tumor cell growth and cellular functions when HIF-1α is silenced. In the present study, the human hepatocellular carcinoma HepG2 cell line was transfected with short hairpin RNA (shRNA) against HIF-1α and cultured under hypoxic conditions (1% O 2 for 24 h). The expression of HIF-1α and various growth factors, including epidermal growth factor (EGF), hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF2), were examined using quantitative polymerase chain reaction and immunoblotting. Tumor growth was measured using a Cell Counting Kit-8 assay and tumor activity was measured using tumor cell invasion and migration assays. Lipopolysaccharide and TAK-242 were used to activate and inhibit TLR4, respectively, to observe the role of TLR4 in the HIF-1α silenced tumor cells. The expression of TLR4 signaling pathway associates, including myeloid differentiation primary response gene 88 (MyD88), apoptosis signal-regulating kinase 1 (ASK1), p38 mitogen-activated protein kinases and HIF-1α, were analyzed by western blot assay. Under hypoxic conditions, silencing of HIF-1α expression suppressed tumor cell growth and regulated the expression of tumor growth-associated genes, including EGF, HGF, VEGF and FG2. Suppression of tumor cell invasion and migration was also observed in the HIF-1α silenced HepG2 cell line. In addition, TLR4 was identified to be involved in HIF-1α and MyD88 accumulation, and activation of ASK1 and p38 were demonstrated to be critical for TLR4-mediated HIF-1α pathway. In conclusion, silencing of HIF-1α expression may induce anti-tumor effects under hypoxic

  20. Hypoxia-Inducible Factor Pathway Inhibition Resolves Tumor Hypoxia and Improves Local Tumor Control After Single-Dose Irradiation

    International Nuclear Information System (INIS)

    Helbig, Linda; Koi, Lydia; Brüchner, Kerstin; Gurtner, Kristin; Hess-Stumpp, Holger; Unterschemmann, Kerstin; Pruschy, Martin

    2014-01-01

    Purpose: To study the effects of BAY-84-7296, a novel orally bioavailable inhibitor of mitochondrial complex I and hypoxia-inducible factor 1 (HIF-1) activity, on hypoxia, microenvironment, and radiation response of tumors. Methods and Materials: UT-SCC-5 and UT-SCC-14 human squamous cell carcinomas were transplanted subcutaneously in nude mice. When tumors reached 4 mm in diameter BAY-84-7296 (Bayer Pharma AG) or carrier was daily administered to the animals. At 7 mm tumors were either excised for Western blot and immunohistologic investigations or were irradiated with single doses. After irradiation animals were randomized to receive BAY-84-7296 maintenance or carrier. Local tumor control was evaluated 150 days after irradiation, and the dose to control 50% of tumors (TCD 50 ) was calculated. Results: BAY-84-7296 decreased nuclear HIF-1α expression. Daily administration of inhibitor for approximately 2 weeks resulted in a marked decrease of pimonidazole hypoxic fraction in UT-SCC-5 (0.5% vs 21%, P 50 , with an enhancement ratio of 1.37 (95% confidence interval [CI] 1.13-1.72) in UT-SCC-5 and of 1.55 (95% CI 1.26-1.94) in UT-SCC-14. BAY-84-7296 maintenance after irradiation did not further decrease TCD 50 . Conclusions: BAY-84-7296 resulted in a marked decrease in tumor hypoxia and substantially reduced radioresistance of tumor cells with the capacity to cause a local recurrence after irradiation. The data suggest that reduction of cellular hypoxia tolerance by BAY-84-7296 may represent the primary biological mechanism underlying the observed enhancement of radiation response. Whether this mechanism contributes to the improved outcome of fractionated chemoradiation therapy warrants further investigation

  1. Andrographolide inhibits the migration, invasion and matrix metalloproteinase expression of rheumatoid arthritis fibroblast-like synoviocytes via inhibition of HIF-1α signaling.

    Science.gov (United States)

    Li, Guo-feng; Qin, Yu-hua; Du, Peng-qiang

    2015-09-01

    Hypoxia is implicated in the pathogenesis of rheumatoid arthritis (RA), contributing to the tumor-like phenotypes of RA fibroblast-like synoviocytes (RA-FLSs). Andrographolide is the main bioactive component of Andrographis paniculata, an herbal medicine that shows therapeutic benefits in RA patients. Here, we explored the effects of andrographolide on hypoxia-induced migration and invasion of RA-FLSs. RA-FLSs were exposed to hypoxia in the presence or absence of andrographolide and cell migration and invasion were tested by Transwell assays. The expression of hypoxia-inducible factor-1 alpha (HIF-1α), matrix metalloproteinase (MMP)-1, MMP-3 and MMP-9 was measured by semi-quantitative reverse transcription polymerase chain reaction and Western blot analysis. HIF-1α DNA binding activity was assessed by electrophoretic mobility shift assay. The effects of overexpression of exogenous HIF-1α on the action of andrographolide in RA-FLSs were investigated. Andrographolide inhibited FLS migration and invasion under hypoxic conditions in a dose-dependent manner. The upregulation of MMP-1, MMP-3 and MMP-9 in response to hypoxia was significantly (Pandrographolide. Moreover, the expression and DNA binding activity of HIF-1α were dose-dependently decreased in andrographolide-treated cells under hypoxic conditions. Overexpression of HIF-1α almost completely reversed the suppressive effects of andrographolide on the migration, invasion and MMP expression of hypoxic RA-FLSs. These results indicate the ability of andrographolide to attenuate hypoxia-induced invasiveness of RA-FLSs via inhibition of HIF-1α signaling, and warrant further exploration of andrographolide for the treatment of RA. Copyright © 2015. Published by Elsevier Inc.

  2. Slit2 ameliorates renal inflammation and fibrosis after hypoxia-and lipopolysaccharide-induced epithelial cells injury in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xiangjun [Department of Urology, Taihe Hospital, Hubei University of Medicine, Hubei (China); Yao, Qisheng, E-mail: yymcyqs@126.com [Department of Urology, Taihe Hospital, Hubei University of Medicine, Hubei (China); Sun, Xinbo; Gong, Xiaoxin; Yang, Yong; Chen, Congbo [Department of Urology, Taihe Hospital, Hubei University of Medicine, Hubei (China); Shan, Guang [Department of Urology, Renmin Hospital of Wuhan University, Hubei (China)

    2017-03-01

    Hypoxic acute kidney injury (AKI) is often incompletely repaired and leads to chronic kidney disease (CKD), which is characterized by tubulointerstitial inflammation and fibrosis. The Slit2 family of secreted glycoproteins is expressed in the kidney, it has been shown to exert an anti-inflammatory activity and prevent ischemic renal injury in vivo. However, whether Slit2 reduces renal fibrosis and inflammation after hypoxic and inflammatory epithelial cells injury in vitro remains unknown. In this study, we aimed to evaluate whether Slit2 ameliorated fibrosis and inflammation in two renal epithelial cells line challenged with hypoxia and lipopolysaccharide (LPS). Renal epithelial cells were treated with hypoxia and LPS to induce cell injury. Hoechst staining and Western blot analysis was conducted to examine epithelial cells injury. Immunofluorescence staining and Western blot analysis was performed to evaluate tubulointerstitial fibrosis. Real-time polymerase chain reaction (PCR) tested the inflammatory factor interleukin (IL)−1β and tumor necrosis factor (TNF)-α, and Western blot analysis determined the hypoxia-inducible factor (HIF)−1α, Toll-like receptor 4 (TLR4) and nuclear factor (NF)-κB. Results revealed that hypoxia induced epithelial cells apoptosis, inflammatory factor IL-1β and TNF-α release and tubulointerstitial fibrosis. LPS could exacerbate hypoxia -induced epithelial cells apoptosis, IL-1β and TNF-α release and fibrosis. Slit2 reduced the expression of fibronectin, the rate of epithelial cell apoptosis, and the expression of inflammatory factor. Slit2 could also inhibit the expression of TLR4 and NF-κB, but not the expression of HIF-1α. Therefore, Slit2 attenuated inflammation and fibrosis after LPS- and hypoxia-induced epithelial cells injury via the TLR4/NF-κB signaling pathway, but not depending on the HIF-1α signaling pathway. - Highlights: • Slit2 ameliorates inflammation after hypoxia-and LPS-induced epithelial cells injury

  3. [Effects of feixin decoction on the contents of hypoxia-inducible factor-1alpha and vascular endothelial growth factor in the rat model of hypoxic pulmonary hypertension].

    Science.gov (United States)

    He, Hong-Jun; Dai, Ai-Guo

    2012-05-01

    To explore the effects of Feixin Decoction (FXD) on the hypoxia-inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) in the rat model of hypoxic pulmonary hypertension (HPH), and to study its mechanisms for treating HPH. Forty healthy male SD rats were randomly divided into four groups, i. e., the normal control group, the HPH model group, the FXD group, and the Nifedipine group, 10 rats in each group. The HPH rat model was prepared using normal pressure intermittent hypoxia method. Except the normal control group, rats in the rest groups were fed in a self-made hypoxic plexiglass cabin, with the poor oxygen condition for 8 h daily for 14 successive days. Then the distilled water (at 30 mL/kg) was given by gastrogavage to rats in the normal control group and the HPH model group. FXD (at 28 g/kg) and Nifedipine (at 20 mg/kg) were given by gastrogavage to rats in the FXD group and the Nifedipine group respectively, once daily, for 14 successive days. Besides, hypoxia was continued for 14 days while medicating. The mean pulmonary artery pressure (mPAP) was detected on the second day after the last medication. The morphology of the pulmonary arteriole was detected. The ratio of pulmonary artery wall area and tube area (WA%) was determined. The protein and mRNA expressions of HIF-1alpha and VEGF were detected using immunohistochemistry and in situ hybridization technique. Compared with the normal control group, mPAP, WA%, and the protein and mRNA expressions of HIF-1alpha and VEGF significantly increased in the model group (P < 0.01, P < 0.05). Compared with the HPH model group, mPAP, WA%, and the protein and mRNA expressions of HIF-1alpha and VEGF significantly decreased in the FXD group (P < 0.01, P < 0.05). FXD down-regulated the expression of VEGF through decreasing the expression of HIF-1alpha. One of its mechanisms for treating HPH might be partially due to reversing the remodeling of pulmonary vascular smooth muscle.

  4. Hypoxia promotes uveal melanoma invasion through enhanced Notch and MAPK activation.

    Directory of Open Access Journals (Sweden)

    Laura Asnaghi

    Full Text Available The transcriptional response promoted by hypoxia-inducible factors has been associated with metastatic spread of uveal melanoma. We found expression of hypoxia-inducible factor 1α (HIF-1α protein in well-vascularized tumor regions as well as in four cell lines grown in normoxia, thus this pathway may be important even in well-oxygenated uveal melanoma cells. HIF-1α protein accumulation in normoxia was inhibited by rapamycin. As expected, hypoxia (1% pO2 further induced HIF-1α protein levels along with its target genes VEGF and LOX. Growth in hypoxia significantly increased cellular invasion of all 5 uveal melanoma lines tested, as did the introduction of an oxygen-insensitive HIF-1α mutant into Mel285 cells with low HIF-1α baseline levels. In contrast, HIF-1α knockdown using shRNA significantly decreased growth in hypoxia, and reduced by more than 50% tumor invasion in four lines with high HIF-1α baseline levels. Pharmacologic blockade of HIF-1α protein expression using digoxin dramatically suppressed cellular invasion both in normoxia and in hypoxia. We found that Notch pathway components, including Jag1-2 ligands, Hes1-Hey1 targets and the intracellular domain of Notch1, were increased in hypoxia, as well as the phosphorylation levels of Erk1-2 and Akt. Pharmacologic and genetic inhibition of Notch largely blocked the hypoxic induction of invasion as did the pharmacologic suppression of Erk1-2 activity. In addition, the increase in Erk1-2 and Akt phosphorylation by hypoxia was partially reduced by inhibiting Notch signaling. Our findings support the functional importance of HIF-1α signaling in promoting the invasive capacity of uveal melanoma cells in both hypoxia and normoxia, and suggest that pharmacologically targeting HIF-1α pathway directly or through blockade of Notch or Erk1-2 pathways can slow tumor spread.

  5. Click Chemistry-based Discovery of [3-Hydroxy-5-(1H-1,2,3-triazol-4-yl)picolinoyl]glycines as Orally Active Hypoxia Inducing Factor Prolyl Hydroxylase Inhibitors with Favorable Safety Profiles for the Treatment of Anemia.

    Science.gov (United States)

    Wu, Yue; Jiang, Zhensheng; Li, Zhihong; Gu, Jing; You, Qi-Dong; Zhang, Xiaojin

    2018-06-01

    As a gene associated with anemia, the erythropoiesis gene is physiologically expressed under hypoxia regulated by hypoxia-inducing factor-α (HIF-α). Thus, stabilizing HIF-α is a potent strategy to stimulate the expression and secretion of erythropoiesis. In this study we applied click chemistry to the discovery of HIF prolyl hydroxylase 2 (HIF-PHD2) inhibitors for the first time and a series of triazole compounds showed preferable inhibitory activity in fluorescence polarization assay. Of particular note was the orally active HIF-PHD inhibitor 15i (IC50 = 62.23 nM), which was almost ten times more active than the phase III drug FG-4592 (IC50 = 591.4 nM). Furthermore, it can upregulate the hemoglobin of cisplatin induced anemia mice (120 g/L) to normal levels (160 g/L) with no apparent toxicity observed in vivo. These results confirm that triazole compound 15i is a promising candidate for the treatment of renal anemia.

  6. Anti-Proliferation and Anti-Invasion Effects of Diosgenin on Gastric Cancer BGC-823 Cells with HIF-1α shRNAs

    Directory of Open Access Journals (Sweden)

    Yuan-Neng Chou

    2012-05-01

    Full Text Available Drug resistance is a major factor for the limited efficacy of chemotherapy in gastric cancer treatment. Hypoxia-inducible factor-1α (HIF-1α, a central transcriptional factor in hypoxia, is suggested to participate in the resistance. Here, we identified a hypoxia-mimic (cobalt chloride sensitive gastric cell line BGC-823 to explore whether diosgenin, an aglycone of steroidal saponins, can inhibit cancer cell invasion and survival of solid tumor in a hypoxic mimic microenvironment. We have shown that diosgenin is a potent candidate for decreasing the ability of invasion and survival in cobalt chloride treated BGC-823 cells. In addition, when combined with HIF-1α specific short hairpin RNA (shRNA, diosgenin can inhibit BGC-823 cells more effectively. The anti-invasion role of diosgenin may be related to E-cadherin, integrinα5 and integrinβ6. These results suggest that diosgenin may be a useful compound in controlling gastric cancer cells in hypoxia condition, especially when combined with down-regulated HIF-1α.

  7. Vanillin Suppresses Cell Motility by Inhibiting STAT3-Mediated HIF-1α mRNA Expression in Malignant Melanoma Cells.

    Science.gov (United States)

    Park, Eun-Ji; Lee, Yoon-Mi; Oh, Taek-In; Kim, Byeong Mo; Lim, Beong-Ou; Lim, Ji-Hong

    2017-03-01

    Recent studies have shown that vanillin has anti-cancer, anti-mutagenic, and anti-metastatic activity; however, the precise molecular mechanism whereby vanillin inhibits metastasis and cancer progression is not fully elucidated. In this study, we examined whether vanillin has anti-cancer and anti-metastatic activities via inhibition of hypoxia-inducible factor-1α (HIF-1α) in A2058 and A375 human malignant melanoma cells. Immunoblotting and quantitative real time (RT)-PCR analysis revealed that vanillin down-regulates HIF-1α protein accumulation and the transcripts of HIF-1α target genes related to cancer metastasis including fibronectin 1 ( FN1 ), lysyl oxidase-like 2 ( LOXL2 ), and urokinase plasminogen activator receptor ( uPAR ). It was also found that vanillin significantly suppresses HIF-1α mRNA expression and de novo HIF-1α protein synthesis. To understand the suppressive mechanism of vanillin on HIF-1α expression, chromatin immunoprecipitation was performed. Consequently, it was found that vanillin causes inhibition of promoter occupancy by signal transducer and activator of transcription 3 (STAT3), but not nuclear factor-κB (NF-κB), on HIF1A . Furthermore, an in vitro migration assay revealed that the motility of melanoma cells stimulated by hypoxia was attenuated by vanillin treatment. In conclusion, we demonstrate that vanillin might be a potential anti-metastatic agent that suppresses metastatic gene expression and migration activity under hypoxia via the STAT3-HIF-1α signaling pathway.

  8. Hypoxia, Epithelial-Mesenchymal Transition, and TET-Mediated Epigenetic Changes

    Directory of Open Access Journals (Sweden)

    Shih-Han Kao

    2016-02-01

    Full Text Available Tumor hypoxia is a pathophysiologic outcome of disrupted microcirculation with inadequate supply of oxygen, leading to enhanced proliferation, epithelial-mesenchymal transition (EMT, metastasis, and chemo-resistance. Epigenetic changes induced by hypoxia are well documented, and they lead to tumor progression. Recent advances show that DNA demethylation mediated by the Ten-eleven translocation (TET proteins induces major epigenetic changes and controls key steps of cancer development. TET enzymes serve as 5mC (5-methylcytosine-specific dioxygenases and cause DNA demethylation. Hypoxia activates the expression of TET1, which also serves as a co-activator of HIF-1α transcriptional regulation to modulate HIF-1α downstream target genes and promote epithelial-mesenchymal transition. As HIF is a negative prognostic factor for tumor progression, hypoxia-activated prodrugs (HAPs may provide a favorable therapeutic approach to lessen hypoxia-induced malignancy.

  9. The hypoxia-inducible factor-responsive proteins semaphorin 4D and vascular endothelial growth factor promote tumor growth and angiogenesis in oral squamous cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Hua; Yang, Ying-Hua [Department of Oncology and Diagnostic Sciences, University of Maryland Dental School, 650W. Baltimore Street, 7-North, Baltimore, MD 21201 (United States); Binmadi, Nada O. [Department of Oncology and Diagnostic Sciences, University of Maryland Dental School, 650W. Baltimore Street, 7-North, Baltimore, MD 21201 (United States); Department of Oral Basic and Clinical Sciences, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Proia, Patrizia [Department of Oncology and Diagnostic Sciences, University of Maryland Dental School, 650W. Baltimore Street, 7-North, Baltimore, MD 21201 (United States); Department of Sports Science (DISMOT), University of Palermo, Via Eleonora Duse 2 90146, Palermo (Italy); Basile, John R., E-mail: jbasile@umaryland.edu [Department of Oncology and Diagnostic Sciences, University of Maryland Dental School, 650W. Baltimore Street, 7-North, Baltimore, MD 21201 (United States); Greenebaum Cancer Center, 22S. Greene Street, Baltimore, MD 21201 (United States)

    2012-08-15

    Growth and metastasis of solid tumors requires induction of angiogenesis to ensure the delivery of oxygen, nutrients and growth factors to rapidly dividing transformed cells. Through either mutations, hypoxia generated by cytoreductive therapies, or when a malignancy outgrows its blood supply, tumor cells undergo a change from an avascular to a neovascular phenotype, a transition mediated by the hypoxia-inducible factor (HIF) family of transcriptional regulators. Vascular endothelial growth factor (VEGF) is one example of a gene whose transcription is stimulated by HIF. VEGF plays a crucial role in promoting tumor growth and survival by stimulating new blood vessel growth in response to such stresses as chemotherapy or radiotherapy-induced hypoxia, and it therefore has become a tempting target for neutralizing antibodies in the treatment of advanced neoplasms. Emerging evidence has shown that the semaphorins, proteins originally associated with control of axonal growth and immunity, are regulated by changes in oxygen tension as well and may play a role in tumor-induced angiogenesis. Through the use of RNA interference, in vitro and in vivo angiogenesis assays and tumor xenograft experiments, we demonstrate that expression of semaphorin 4D (SEMA4D), which is under the control of the HIF-family of transcription factors, cooperates with VEGF to promote tumor growth and vascularity in oral squamous cell carcinoma (OSCC). We use blocking antibodies to show that targeting SEMA4D function along with VEGF could represent a novel anti-angiogenic therapeutic strategy for the treatment of OSCC and other solid tumors. -- Highlights: Black-Right-Pointing-Pointer Similar to VEGF, SEMA4D promotes angiogenesis in vitro and in vivo. Black-Right-Pointing-Pointer Both VEGF and SEMA4D are produced by OSCC cells in a HIF-dependent manner. Black-Right-Pointing-Pointer These factors combine to elicit a robust pro-angiogenic phenotype in OSCC. Black-Right-Pointing-Pointer Anti-SEMA4D

  10. The hypoxia-inducible factor-responsive proteins semaphorin 4D and vascular endothelial growth factor promote tumor growth and angiogenesis in oral squamous cell carcinoma

    International Nuclear Information System (INIS)

    Zhou, Hua; Yang, Ying-Hua; Binmadi, Nada O.; Proia, Patrizia; Basile, John R.

    2012-01-01

    Growth and metastasis of solid tumors requires induction of angiogenesis to ensure the delivery of oxygen, nutrients and growth factors to rapidly dividing transformed cells. Through either mutations, hypoxia generated by cytoreductive therapies, or when a malignancy outgrows its blood supply, tumor cells undergo a change from an avascular to a neovascular phenotype, a transition mediated by the hypoxia-inducible factor (HIF) family of transcriptional regulators. Vascular endothelial growth factor (VEGF) is one example of a gene whose transcription is stimulated by HIF. VEGF plays a crucial role in promoting tumor growth and survival by stimulating new blood vessel growth in response to such stresses as chemotherapy or radiotherapy-induced hypoxia, and it therefore has become a tempting target for neutralizing antibodies in the treatment of advanced neoplasms. Emerging evidence has shown that the semaphorins, proteins originally associated with control of axonal growth and immunity, are regulated by changes in oxygen tension as well and may play a role in tumor-induced angiogenesis. Through the use of RNA interference, in vitro and in vivo angiogenesis assays and tumor xenograft experiments, we demonstrate that expression of semaphorin 4D (SEMA4D), which is under the control of the HIF-family of transcription factors, cooperates with VEGF to promote tumor growth and vascularity in oral squamous cell carcinoma (OSCC). We use blocking antibodies to show that targeting SEMA4D function along with VEGF could represent a novel anti-angiogenic therapeutic strategy for the treatment of OSCC and other solid tumors. -- Highlights: ► Similar to VEGF, SEMA4D promotes angiogenesis in vitro and in vivo. ► Both VEGF and SEMA4D are produced by OSCC cells in a HIF-dependent manner. ► These factors combine to elicit a robust pro-angiogenic phenotype in OSCC. ► Anti-SEMA4D blocking antibody inhibits Plexin-B1 activation. ► SEMA4D is a valid anti-angiogenic target in the

  11. Inhibitory PAS domain protein is a negative regulator of hypoxia-inducible gene expression

    Science.gov (United States)

    Makino, Yuichi; Cao, Renhai; Svensson, Kristian; Bertilsson, Göran; Asman, Mikael; Tanaka, Hirotoshi; Cao, Yihai; Berkenstam, Anders; Poellinger, Lorenz

    2001-11-01

    Alteration of gene expression is a crucial component of adaptive responses to hypoxia. These responses are mediated by hypoxia-inducible transcription factors (HIFs). Here we describe an inhibitory PAS (Per/Arnt/Sim) domain protein, IPAS, which is a basic helix-loop-helix (bHLH)/PAS protein structurally related to HIFs. IPAS contains no endogenous transactivation function but demonstrates dominant negative regulation of HIF-mediated control of gene expression. Ectopic expression of IPAS in hepatoma cells selectively impairs induction of genes involved in adaptation to a hypoxic environment, notably the vascular endothelial growth factor (VEGF) gene, and results in retarded tumour growth and tumour vascular density in vivo. In mice, IPAS was predominantly expressed in Purkinje cells of the cerebellum and in corneal epithelium of the eye. Expression of IPAS in the cornea correlates with low levels of expression of the VEGF gene under hypoxic conditions. Application of an IPAS antisense oligonucleotide to the mouse cornea induced angiogenesis under normal oxygen conditions, and demonstrated hypoxia-dependent induction of VEGF gene expression in hypoxic corneal cells. These results indicate a previously unknown mechanism for negative regulation of angiogenesis and maintenance of an avascular phenotype.

  12. Novel mechanism of cardiac protection by valsartan: synergetic roles of TGF-β1 and HIF-1α in Ang II-mediated fibrosis after myocardial infarction.

    Science.gov (United States)

    Sui, Xizhong; Wei, Hongchao; Wang, Dacheng

    2015-08-01

    Transforming growth factor (TGF)-β1 is a known factor in angiotensin II (Ang II)-mediated cardiac fibrosis after myocardial infarction (MI). Hypoxia inducible factor-1 (Hif-1α) was recently demonstrated to involve in the tissue fibrosis and influenced by Ang II. However, whether Hif-1α contributed to the Ang II-mediated cardiac fibrosis after MI, and whether interaction or synergetic roles between Hif-1α and TGF-β pathways existed in the process was unclear. In vitro, cardiac cells were incubated under hypoxia or Ang II to mimic ischaemia. In vivo, valsartan was intravenously injected into Sprague-Dawley rats with MI daily for 1 week; saline and hydralazine (another anti-hypertensive agent like valsartan) was used as control. The fibrosis-related proteins were detected by Western blotting. Cardiac structure and function were assessed with multimodality methods. We demonstrated in vitro that hypoxia would induce the up-regulation of Ang II, TGF-β/Smad and Hif-1α, which further induced collagen accumulation. By blocking with valsartan, a blocker of Ang II type I (AT1) receptor, we confirmed that the up-regulation of TGF-β/Smad and Hif-1α was through the Ang II-mediated pathway. By administering TGF-β or dimethyloxalylglycine, we determined that both TGF-β/Smad and Hif-1α contributed to Ang II-mediated collagen accumulation and a synergetic effect between them was observed. Consistent with in vitro results, valsartan significantly attenuated the expression of TGF-β/Smad, Hif-1α and fibrosis-related protein in rats after MI. Heart function, infarcted size, wall thickness as well as myocardial vascularization of ischaemic hearts were also significantly improved by valsartan compared with saline and hydralazine. Our study may provide novel insights into the mechanisms of Ang II-induced cardiac fibrosis as well as into the cardiac protection of valsartan. © 2015 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and

  13. The yeast genome may harbor hypoxia response elements (HRE).

    Science.gov (United States)

    Ferreira, Túlio César; Hertzberg, Libi; Gassmann, Max; Campos, Elida Geralda

    2007-01-01

    The hypoxia-inducible factor-1 (HIF-1) is a heterodimeric transcription factor activated when cells are submitted to hypoxia. The heterodimer is composed of two subunits, HIF-1alpha and the constitutively expressed HIF-1beta. During normoxia, HIF-1alpha is degraded by the 26S proteasome, but hypoxia causes HIF-1alpha to be stabilized, enter the nucleus and bind to HIF-1beta, thus forming the active complex. The complex then binds to the regulatory sequences of various genes involved in physiological and pathological processes. The specific regulatory sequence recognized by HIF-1 is the hypoxia response element (HRE) that has the consensus sequence 5'BRCGTGVBBB3'. Although the basic transcriptional regulation machinery is conserved between yeast and mammals, Saccharomyces cerevisiae does not express HIF-1 subunits. However, we hypothesized that baker's yeast has a protein analogous to HIF-1 which participates in the response to changes in oxygen levels by binding to HRE sequences. In this study we screened the yeast genome for HREs using probabilistic motif search tools. We described 24 yeast genes containing motifs with high probability of being HREs (p-value<0.1) and classified them according to biological function. Our results show that S. cerevisiae may harbor HREs and indicate that a transcription factor analogous to HIF-1 may exist in this organism.

  14. MicroRNA 107 partly inhibits endothelial progenitor cells differentiation via HIF-1β.

    Directory of Open Access Journals (Sweden)

    Shu Meng

    Full Text Available Endothelial progenitor cells (EPCs play an important role in tissue repair after ischemic heart disease. In particular, the recovery of endothelial function is reliant on the ability and rate of EPCs differentiate into mature endothelial cells. The present study evaluated the effect of microRNA 107 (miR-107 on the mechanism of EPCs differentiation. EPCs were isolated from rats' bone marrow and miR-107 expression of EPCs in hypoxic and normoxic conditions were measured by real-time qualitative PCR. CD31 was analyzed by flow cytometry and eNOS was examined by real-time qualitative PCR and western blotting and these were used as markers of EPC differentiation. In order to reveal the mechanism, we used miR107 inhibitor and lentiviral vector expressing a short hairpin RNA (shRNA that targets miR-107 and hypoxia-inducible factor-1 β (HIF-1β to alter miR107 and HIF-1β expression. MiR-107 expression were increased in EPCs under hypoxic conditions. Up-regulation of miR-107 partly suppressed the EPCs differentiation induced in hypoxia, while down-regulation of miR-107 promoted EPC differentiation. HIF-1β was the target. This study indicated that miR-107 was up-regulated in hypoxia to prevent EPCs differentiation via its target HIF-1β. The physiological mechanisms of miR-107 must be evaluated if it is to be used as a potential anti-ischemia therapeutic regime.

  15. Endothelial monocyte activating polypeptide-II modulates endothelial cell responses by degrading hypoxia-inducible factor-1alpha through interaction with PSMA7, a component of the proteasome

    International Nuclear Information System (INIS)

    Tandle, Anita T.; Calvani, Maura; Uranchimeg, Badarch; Zahavi, David; Melillo, Giovanni; Libutti, Steven K.

    2009-01-01

    The majority of human tumors are angiogenesis dependent. Understanding the specific mechanisms that contribute to angiogenesis may offer the best approach to develop therapies to inhibit angiogenesis in cancer. Endothelial monocyte activating polypeptide-II (EMAP-II) is an anti-angiogenic cytokine with potent effects on endothelial cells (ECs). It inhibits EC proliferation and cord formation, and it suppresses primary and metastatic tumor growth in-vivo. However, very little is known about the molecular mechanisms behind the anti-angiogenic activity of EMAP-II. In the present study, we explored the molecular mechanism behind the anti-angiogenic activity exerted by this protein on ECs. Our results demonstrate that EMAP-II binds to the cell surface α5β1 integrin receptor. The cell surface binding of EMAP-II results in its internalization into the cytoplasmic compartment where it interacts with its cytoplasmic partner PSMA7, a component of the proteasome degradation pathway. This interaction increases hypoxia-inducible factor 1-alpha (HIF-1α) degradation under hypoxic conditions. The degradation results in the inhibition of HIF-1α mediated transcriptional activity as well as HIF-1α mediated angiogenic sprouting of ECs. HIF-1α plays a critical role in angiogenesis by activating a variety of angiogenic growth factors. Our results suggest that one of the major anti-angiogenic functions of EMAP-II is exerted through its inhibition of the HIF-1α activities.

  16. Endothelial monocyte activating polypeptide-II modulates endothelial cell responses by degrading hypoxia-inducible factor-1alpha through interaction with PSMA7, a component of the proteasome

    Energy Technology Data Exchange (ETDEWEB)

    Tandle, Anita T. [Tumor Angiogenesis Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892 (United States); Calvani, Maura; Uranchimeg, Badarch [DTP-Tumor Hypoxia Laboratory, SAIC Frederick, Inc., National Cancer Institute, Frederick, Maryland 21702 (United States); Zahavi, David [Tumor Angiogenesis Section, Surgery Branch, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland 20892 (United States); Melillo, Giovanni [DTP-Tumor Hypoxia Laboratory, SAIC Frederick, Inc., National Cancer Institute, Frederick, Maryland 21702 (United States); Libutti, Steven K., E-mail: slibutti@montefiore.org [Department of Surgery, Montefiore-Einstein Center for Cancer Care, Albert Einstein College of Medicine, Greene Medical Arts Pavilion, 4th Floor 3400, Bainbridge Avenue, Bronx, New York 10467 (United States)

    2009-07-01

    The majority of human tumors are angiogenesis dependent. Understanding the specific mechanisms that contribute to angiogenesis may offer the best approach to develop therapies to inhibit angiogenesis in cancer. Endothelial monocyte activating polypeptide-II (EMAP-II) is an anti-angiogenic cytokine with potent effects on endothelial cells (ECs). It inhibits EC proliferation and cord formation, and it suppresses primary and metastatic tumor growth in-vivo. However, very little is known about the molecular mechanisms behind the anti-angiogenic activity of EMAP-II. In the present study, we explored the molecular mechanism behind the anti-angiogenic activity exerted by this protein on ECs. Our results demonstrate that EMAP-II binds to the cell surface {alpha}5{beta}1 integrin receptor. The cell surface binding of EMAP-II results in its internalization into the cytoplasmic compartment where it interacts with its cytoplasmic partner PSMA7, a component of the proteasome degradation pathway. This interaction increases hypoxia-inducible factor 1-alpha (HIF-1{alpha}) degradation under hypoxic conditions. The degradation results in the inhibition of HIF-1{alpha} mediated transcriptional activity as well as HIF-1{alpha} mediated angiogenic sprouting of ECs. HIF-1{alpha} plays a critical role in angiogenesis by activating a variety of angiogenic growth factors. Our results suggest that one of the major anti-angiogenic functions of EMAP-II is exerted through its inhibition of the HIF-1{alpha} activities.

  17. Expression of DDX3 is directly modulated by hypoxia inducible factor-1 alpha in breast epithelial cells.

    Directory of Open Access Journals (Sweden)

    Mahendran Botlagunta

    2011-03-01

    Full Text Available DEAD box protein, DDX3, is aberrantly expressed in breast cancer cells ranging from weakly invasive to aggressive phenotypes and functions as an important regulator of cancer cell growth and survival. Here, we demonstrate that hypoxia inducible factor-1α is a transcriptional activator of DDX3 in breast cancer cells. Within the promoter region of the human DDX3 gene, we identified three putative hypoxia inducible factor-1 responsive elements. By luciferase reporter assays in combination with mutated hypoxia inducible factor-1 responsive elements, we determined that the hypoxia inducible factor-1 responsive element at position -153 relative to the translation start site is essential for transcriptional activation of DDX3 under hypoxic conditions. We also demonstrated that hypoxia inducible factor-1 binds to the DDX3 promoter and that the binding is specific, as revealed by siRNA against hypoxia inducible factor-1 and chromatin immunoprecipitation assays. Thus, the activation of DDX3 expression during hypoxia is due to the direct binding of hypoxia inducible factor-1 to hypoxia responsive elements in the DDX3 promoter. In addition, we observed a significant overlap in the protein expression pattern of hypoxia inducible factor-1α and DDX3 in MDA-MB-231 xenograft tumors. Taken together, our results demonstrate, for the first time, the role of DDX3 as a hypoxia-inducible gene that exhibits enhanced expression through the interaction of hypoxia inducible factor-1 with hypoxia inducible factor-1 responsive elements in its promoter region.

  18. [Characteristics of sublingual vein and expressions of vascular endothelial growth factor and hypoxia-inducible factor 1alpha proteins in sublingual tissues of Beagle dogs with portal hypertension].

    Science.gov (United States)

    Li, Bai-yu; Wang, Li-na; Yue, Xiao-qiang; Li, Bai

    2009-05-01

    To observe sublingual vein characteristics and the expressions of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1alpha (HIF-1alpha) proteins in sublingual tissues of Beagle dogs with cirrhotic portal hypertension. Twelve Beagle dogs were randomly divided into normal control group and cirrhotic portal hypertension group. There were 6 dogs in each group. A canine model of cirrhosis portal hypertension was established by injecting dimethylnitrosamine (DMN) into portal vein once a week for 7 weeks. The characteristics of sublingual vein were observed. Portal venous pressure was measured by using bioelectric recording techniques. The expressions of VEGF and HIF-1alpha proteins in sublingual vein were detected by immunohistochemical method. The shape and color of sublingual vein in beagle dogs in the cirrhotic portal hypertension group changed obviously as compared with the normal control group. Immunohistochemical results showed that there were almost no expressions of VEGF and HIF-1alpha proteins in sublingual tissues in the normal control group; however, the expressions of VEGF and HIF-1alpha proteins in sublingual tissues in the cirrhotic portal hypertension group significantly increased. Changes of portal pressure may lead to the formation of the abnormal sublingual vein by increasing the expressions of VEGF and HIF-1alpha proteins in sublingual tissues in Beagle dogs with portal hypertension.

  19. The effect of within-instar development on tracheal diameter and hypoxia-inducible factors α and β in the tobacco hornworm, Manduca sexta.

    Science.gov (United States)

    Lundquist, Taylor A; Kittilson, Jeffrey D; Ahsan, Rubina; Greenlee, Kendra J

    2017-12-12

    As insects grow within an instar, body mass increases, often more than doubling. The increase in mass causes an increase in metabolic rate and hence oxygen demand. However, the insect tracheal system is hypothesized to increase only after molting and may be compressed as tissues grow within an instar. The increase in oxygen demand in the face of a potentially fixed or decreasing supply could result in hypoxia as insects near the end of an instar. To test these hypotheses, we first used synchrotron X-ray imaging to determine how diameters of large tracheae change within an instar and after molting to the next instar in the tobacco hornworm, Manduca sexta. Large tracheae did not increase in diameter within the first, second, third, and fourth instars, but increased upon molting. To determine if insects are hypoxic at the end of instars, we used the presence of hypoxia-inducible factors (HIFs) as an index. HIF-α and HIF-β dimerize in hypoxia and act as a transcription factor that turns on genes that will increase oxygen delivery. We sequenced both of these genes and measured their mRNA levels at the beginning and end of each larval instar. Finally, we obtained an antibody to HIF-α and measured protein expression during the same time. Both mRNA and protein levels of HIFs were increased at the end of most instars. These data support the hypothesis that some insects may experience hypoxia at the end of an instar, which could be a signal for molting. As caterpillars grow within an instar, major tracheae do not increase in size, while metabolic demand increases. At the same life stages, caterpillars increased expression of hypoxia inducible factors, suggesting that they become hypoxic near the end of an instar. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Optical Imaging of Tumor Hypoxia and Evaluation of Efficacy of a Hypoxia-Targeting Drug in Living Animals

    Directory of Open Access Journals (Sweden)

    Hiroshi Harada

    2005-07-01

    Full Text Available Solid tumors containing more hypoxic regions show a more malignant phenotype by increasing the expression of genes encoding angiogenic and metastatic factors. Hypoxia-inducible factor-1 (HIF-1 is a master transcriptional activator of such genes, and thus, imaging and targeting hypoxic tumor cells where HIF-1 is active are important in cancer therapy. In the present study, HIF-1 activity was monitored via an optical in vivo imaging system by using a luciferase reporter gene under the regulation of an artificial HIF-1-dependent promoter, 5HRE. To monitor tumor hypoxia, we isolated a stable reporter-transfectant, HeLa/5HRE-Luc, which expressed more than 100-fold luciferase in response to hypoxic stress, and observed bioluminescence from its xenografts. Immunohistochemical analysis of the xenografts with a hypoxia marker, pimonidazole, confirmed that the luciferase-expressing cells were hypoxic. Evaluation of the efficacy of a hypoxia-targeting prodrug, TOP3, using this optical imaging system revealed that hypoxic cells were significantly diminished by TOP3 treatment. Immunohistochemical analysis of the TOP3-treated xenografts confirmed that hypoxic cells underwent apoptosis and were removed after TOP3 treatment. These results demonstrate that this model system using the 5HRE-luciferase reporter construct provides qualitative information (hypoxic status of solid tumors and enables one to conveniently evaluate the efficacy of cancer therapy on hypoxia in malignant solid tumors.

  1. A genetically encoded biosensor for visualising hypoxia responses in vivo

    Directory of Open Access Journals (Sweden)

    Tvisha Misra

    2017-02-01

    Full Text Available Cells experience different oxygen concentrations depending on location, organismal developmental stage, and physiological or pathological conditions. Responses to reduced oxygen levels (hypoxia rely on the conserved hypoxia-inducible factor 1 (HIF-1. Understanding the developmental and tissue-specific responses to changing oxygen levels has been limited by the lack of adequate tools for monitoring HIF-1 in vivo. To visualise and analyse HIF-1 dynamics in Drosophila, we used a hypoxia biosensor consisting of GFP fused to the oxygen-dependent degradation domain (ODD of the HIF-1 homologue Sima. GFP-ODD responds to changing oxygen levels and to genetic manipulations of the hypoxia pathway, reflecting oxygen-dependent regulation of HIF-1 at the single-cell level. Ratiometric imaging of GFP-ODD and a red-fluorescent reference protein reveals tissue-specific differences in the cellular hypoxic status at ambient normoxia. Strikingly, cells in the larval brain show distinct hypoxic states that correlate with the distribution and relative densities of respiratory tubes. We present a set of genetic and image analysis tools that enable new approaches to map hypoxic microenvironments, to probe effects of perturbations on hypoxic signalling, and to identify new regulators of the hypoxia response.

  2. Gene expression and enzyme activities of carbonic anhydrase and glutaminase in rat kidneys induced by chronic systemic hypoxia

    Directory of Open Access Journals (Sweden)

    Andi N.K. Syarifin

    2015-11-01

    Full Text Available Background: Hypoxia can cause acidosis. Kidney plays an essential role in maintaining acid-base balance, which involves the activities of carbonic anhydrase (CA and glutaminase (GLS. This study is aimed to determine the expression and activities of the CA9 and GLS1 enzymes in relation to hypoxia inducible factor-1α (HIF-1α, a transcription factor protein which is a marker of hypoxia.Methods: This study was an in vivo experimental study with coupled paralel design. used 25 male Sprague-Dawley rats weighing 150-200 g. Rats were divided into 5 groups: the control group (normoxic condition and 4 treatment groups. The latter were kept in a hypoxic chamber (10% O2: 90% N2 for 1, 3, 5 and 7 days. All rats were euthanized after treatment, kidneys excised, tissues homogenized and investigated for gene expression of CA9, GLS1 and HIF-1α. On protein level, total enzymatic activities of CA and GLS and protein of HIF-1α were also investigated. Data were analyzed statistically using ANOVA for significance, and as its alternative, used Mann-Whitney and Kruskal-Wallis test.Results: Results showed that HIF-1α mRNA increased during hypoxia, but not HIF-1α protein. It seemed that acidosis occurs in kidney tissue, indicated by increased CA9 and GLS1 mRNA expression and specific activity of total CA and GLS1. Expression of CA9 and GLS1 mRNA both showed strong positive correlation with HIF-1α mRNA, but not with HIF-1α protein.Conclusion: It is suggested that during chronic systemic hypoxia, gene expression of CA9 and GLS1 and their enzyme activities were increased as a response to acidosis and related with the expression of HIF-1α mRNA.

  3. Digoxin Downregulates NDRG1 and VEGF through the Inhibition of HIF-1α under Hypoxic Conditions in Human Lung Adenocarcinoma A549 Cells

    Directory of Open Access Journals (Sweden)

    Dong Wei

    2013-04-01

    Full Text Available Digoxin, an inhibitor of Na+/K+ ATPase, has been used in the treatment of heart-related diseases (such as congestive heart failure and atrial arrhythmia for decades. Recently, it was reported that digoxin is also an effective HIF-1α inhibitor. We investigated whether digoxin could suppress tumor cell growth through HIF-1α in non-small cell lung cancer cells (A549 cells under hypoxic conditions. An MTT assay was used to measure cell viability. RT-PCR and western blotting were performed to analyze the mRNA and protein expression of VEGF, NDRG1, and HIF-1α. HIF-1α nuclear translocation was then determined by EMSA. Digoxin was found to inhibit the proliferation of A549 cells under hypoxic conditions. Our results showed that hypoxia led to the upregulation of VEGF, NDRG1, and HIF-1α both at the mRNA and protein levels. We also found that the hypoxia-induced overexpression of VEGF, NDRG1, and HIF-1α was suppressed by digoxin in a concentration-dependent manner. As expected, our EMSA results demonstrated that under hypoxic conditions HIF-1α nuclear translocation was also markedly reduced by digoxin in a concentration-dependent manner. Our results suggest that digoxin downregulated hypoxia-induced overexpression of VEGF and NDRG1 at the transcriptional level probably through the inhibition of HIF-1α synthesis in A549 cells.

  4. Desferrioxamine, an iron chelator, enhances HIF-1α accumulation via cyclooxygenase-2 signaling pathway

    International Nuclear Information System (INIS)

    Woo, Kyung Jin; Lee, Tae-Jin; Park, Jong-Wook; Kwon, Taeg Kyu

    2006-01-01

    Cyclooxygenase-2 (COX-2) is an important inducible enzyme in inflammation and is overexpressed in a variety of cancers. Evidence is rapidly accumulating that chronic inflammation may contribute to carcinogenesis through increase of cell proliferation, angiogenesis, and metastasis in a number of neoplasms, including colorectal carcinoma. In the present study, we investigated some mechanistic aspects of DFX-induced hypoxia-driven COX-2 expression. Desferrioxamine (DFX), an iron chelator, is known to upregulate inflammatory mediators. DFX induced the expression of COX-2 and accumulation of HIF-1α protein in dose-dependent manners, but hypoxia mimetic agent cobalt chloride (CoCl 2 ) induced accumulation of HIF-1α protein but not increase of COX-2 expression. DFX-induced increase of COX-2 expression and HIF-1α protein level was attenuated by addition of ferric citrate. This result suggested that the iron chelating function of DFX was important to induce the increase of COX-2 and HIF-1α protein. PD98059 significantly inhibited the induction of COX-2 protein and accumulation of HIF-1α, suggesting that DFX-induced increase of HIF-1α and COX-2 protein was mediated, at least in part, through the ERK signaling pathway. In addition, pretreatment with NS-398 to inhibit COX-2 activity also effectively suppressed DFX-induced HIF-1α accumulation in human colon cancer cells, providing the evidence that COX-2 plays as a regulator of HIF-1α accumulation in DFX-treated colon cancer cells. Together, our findings suggest that iron metabolism may regulate stabilization of HIF-1α protein by modulating cyclooxygenase-2 signaling pathway

  5. Silencing of osteopontin promotes the radiosensitivity of breast cancer cells by reducing the expression of hypoxia inducible factor 1 and vascular endothelial growth factor

    Institute of Scientific and Technical Information of China (English)

    YANG Li; ZHAO Wei; ZUO Wen-shu; WEI Ling; SONG Xian-rang; WANG Xing-wu; ZHENG Gang; ZHENG Mei-zhu

    2012-01-01

    Background Osteopontin (OPN) is a secreted phosphoglycoprotein (SSP) that is overexpressed in a variety of tumors and was regarded as a molecular marker of tumors.In this study,we intended to demonstrate the role of OPN in human breast cancer cell line MDA-MB-231.Methods Recombinant plasmid expressing small interfering RNA (siRNA) specific to OPN mRNA was transfected into MDA-MB-231 cells to generate the stable transfected cell line MDA-MB-343,and the empty plasmid tansfected cells (MDA-MB-neg) or wildtype MDA-MB-231 cells were used as control cells respectively.Expression of OPN,hypoxia inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) proteins was analyzed by Western blotting analysis.The radiosensitivity of cells was determined by detecting cell apoptosis,cell proliferation and cell senescence.Results HIF-1 and VEGF proteins in MDA-MB-343 cells were significantly downregulated upon the efficient knockdown of OPN expression under either hypoxia or normoxia environment.Moreover,expression of OPN protein was upregualted upon hypoxic culture.Stable OPN-silencing also decreased cell invasion,increased cell apoptosis and cell senescence,as well as reduced clonogenic survival,resulting in increase radiation tolerance.Conclusions Suppression of OPN gene expression can enhance radiosensitivity and affect cell apoptosis in breast cancer cells.OPN seems to be an attractive target for the improvement of radiotherapy.

  6. Non-electron transfer chain mitochondrial defects differently regulate HIF-1α degradation and transcription

    Directory of Open Access Journals (Sweden)

    Antonina N. Shvetsova

    2017-08-01

    Full Text Available Mitochondria are the main consumers of molecular O2 in a cell as well as an abundant source of reactive oxygen species (ROS. Both, molecular oxygen and ROS are powerful regulators of the hypoxia-inducible factor-1α-subunit (HIF-α. While a number of mechanisms in the oxygen-dependent HIF-α regulation are quite well known, the view with respect to mitochondria is less clear. Several approaches using pharmacological or genetic tools targeting the mitochondrial electron transport chain (ETC indicated that ROS, mainly formed at the Rieske cluster of complex III of the ETC, are drivers of HIF-1α activation. However, studies investigating non-ETC located mitochondrial defects and their effects on HIF-1α regulation are scarce, if at all existing. Thus, in the present study we examined three cell lines with non-ETC mitochondrial defects and focused on HIF-1α degradation and transcription, target gene expression, as well as ROS levels. We found that cells lacking the key enzyme 2-enoyl thioester reductase/mitochondrial enoyl-CoA reductase (MECR, and cells lacking manganese superoxide dismutase (MnSOD showed a reduced induction of HIF-1α under long-term (20 h hypoxia. By contrast, cells lacking the mitochondrial DNA depletion syndrome channel protein Mpv17 displayed enhanced levels of HIF-1α already under normoxic conditions. Further, we show that ROS do not exert a uniform pattern when mediating their effects on HIF-1α, although all mitochondrial defects in the used cell types increased ROS formation. Moreover, all defects caused a different HIF-1α regulation via promoting HIF-1α degradation as well as via changes in HIF-1α transcription. Thereby, MECR- and MnSOD-deficient cells showed a reduction in HIF-1α mRNA levels whereas the Mpv17 lacking cells displayed enhanced HIF-1α mRNA levels under normoxia and hypoxia. Altogether, our study shows for the first time that mitochondrial defects which are not related to the ETC and Krebs cycle

  7. Hypoxia Inducible Factor-2 Alpha and Prolinhydroxylase 2 Polymorphisms in Patients with Acute Respiratory Distress Syndrome (ARDS

    Directory of Open Access Journals (Sweden)

    Annika Dötsch

    2017-06-01

    Full Text Available Hypoxia-inducible-factor-2α (HIF-2α and HIF-2 degrading prolyl-hydroxylases (PHD are key regulators of adaptive hypoxic responses i.e., in acute respiratory distress syndrome (ARDS. Specifically, functionally active genetic variants of HIF-2α (single nucleotide polymorphism (SNP [ch2:46441523(hg18] and PHD2 (C/T; SNP rs516651 and T/C; SNP rs480902 are associated with improved adaptation to hypoxia i.e., in high-altitude residents. However, little is known about these SNPs’ prevalence in Caucasians and impact on ARDS-outcome. Thus, we tested the hypotheses that in Caucasian ARDS patients SNPs in HIF-2α or PHD2 genes are (1 common, and (2 independent risk factors for 30-day mortality. After ethics-committee approval, 272 ARDS patients were prospectively included, genotyped for PHD2 (Taqman SNP Genotyping Assay and HIF-2α-polymorphism (restriction digest + agarose-gel visualization, and genotype dependent 30-day mortality was analyzed using Kaplan-Meier-plots and multivariate Cox-regression analyses. Frequencies were 99.62% for homozygous HIF-2α CC-carriers (CG: 0.38%; GG: 0%, 2.3% for homozygous PHD2 SNP rs516651 TT-carriers (CT: 18.9%; CC: 78.8%, and 3.7% for homozygous PHD2 SNP rs480902 TT-carriers (CT: 43.9%; CC: 52.4%. PHD2 rs516651 TT-genotype in ARDS was independently associated with a 3.34 times greater mortality risk (OR 3.34, CI 1.09–10.22; p = 0.034 within 30-days, whereas the other SNPs had no significant impact (p = ns. The homozygous HIF-2α GG-genotype was not present in our Caucasian ARDS cohort; however PHD2 SNPs exist in Caucasians, and PHD2 rs516651 TT-genotype was associated with an increased 30-day mortality suggesting a relevance for adaptive responses in ARDS.

  8. HIF1α deficiency reduces inflammation in a mouse model of proximal colon cancer

    Directory of Open Access Journals (Sweden)

    Dessislava N. Mladenova

    2015-09-01

    Full Text Available Hypoxia-inducible factor 1α (HIF1α is a transcription factor that regulates the adaptation of cells to hypoxic microenvironments, for example inside solid tumours. Stabilisation of HIF1α can also occur in normoxic conditions in inflamed tissue or as a result of inactivating mutations in negative regulators of HIF1α. Aberrant overexpression of HIF1α in many different cancers has led to intensive efforts to develop HIF1α-targeted therapies. However, the role of HIF1α is still poorly understood in chronic inflammation that predisposes the colon to carcinogenesis. We have previously reported that the transcription of HIF1α is upregulated and that the protein is stabilised in inflammatory lesions that are caused by the non-steroidal anti-inflammatory drug (NSAID sulindac in the mouse proximal colon. Here, we exploited this side effect of long-term sulindac administration to analyse the role of HIF1α in colon inflammation using mice with a Villin-Cre-induced deletion of Hif1α exon 2 in the intestinal epithelium (Hif1αΔIEC. We also analysed the effect of sulindac sulfide on the aryl hydrocarbon receptor (AHR pathway in vitro in colon cancer cells. Most sulindac-treated mice developed visible lesions, resembling the appearance of flat adenomas in the human colon, surrounded by macroscopically normal mucosa. Hif1αΔIEC mice still developed lesions but they were smaller than in the Hif1α-floxed siblings (Hif1αF/F. Microscopically, Hif1αΔIEC mice had significantly less severe colon inflammation than Hif1αF/F mice. Molecular analysis showed reduced MIF expression and increased E-cadherin mRNA expression in the colon of sulindac-treated Hif1αΔIEC mice. However, immunohistochemistry analysis revealed a defect of E-cadherin protein expression in sulindac-treated Hif1αΔIEC mice. Sulindac sulfide treatment in vitro upregulated Hif1α, c-JUN and IL8 expression through the AHR pathway. Taken together, HIF1α expression augments inflammation

  9. Requirement of Hsp105 in CoCl{sub 2}-induced HIF-1α accumulation and transcriptional activation

    Energy Technology Data Exchange (ETDEWEB)

    Mikami, Hiroki; Saito, Youhei, E-mail: ysaito@mb.kyoto-phu.ac.jp; Okamoto, Namiko; Kakihana, Ayana; Kuga, Takahisa; Nakayama, Yuji, E-mail: nakayama@mb.kyoto-phu.ac.jp

    2017-03-15

    The mammalian stress protein Hsp105α protects cells from stress conditions. Several studies have indicated that Hsp105α is overexpressed in many types of solid tumors, which contain hypoxic microenvironments. However, the role of Hsp105α in hypoxic tumors remains largely unknown. We herein demonstrated the involvement of Hsp105α in HIF-1 functions induced by the hypoxia-mimetic agent CoCl{sub 2}. While Hsp105α is mainly localized in the cytoplasm under normal conditions, a treatment with CoCl{sub 2} induces the nuclear localization of Hsp105α, which correlated with HIF-1α expression levels. The overexpression of degradation-resistant HIF-1α enhances the nuclear localization of Hsp105α without the CoCl{sub 2} treatment. The CoCl{sub 2}-dependent transcriptional activation of HIF-1, which is measured using a reporter gene containing a HIF-responsive element, is reduced by the knockdown of Hsp105α. Furthermore, the CoCl{sub 2}-induced accumulation of HIF-1α is enhanced by heat shock, which results in the nuclear localization of Hsp105, and is suppressed by the knockdown of Hsp105. Hsp105 associates with HIF-1α in CoCl{sub 2}-treated cells. These results suggest that Hsp105α plays an important role in the functions of HIF-1 under hypoxic conditions, in which Hsp105α enhances the accumulation and transcriptional activity of HIF-1 through the HIF-1α-mediated nuclear localization of Hsp105α. - Highlights: • Hsp105α is required for the CoCl{sub 2}-induced transcriptional activation and accumulation of HIF-1. • Hsp105α localizes to the nucleus and interacts with HIF-1α in CoCl{sub 2}-treated cells. • Hsp105 enhances the CoCl{sub 2}-induced accumulation of HIF-1α under heat shock conditions.

  10. Hypoxia-inducing factors as master regulators of stemness properties and altered metabolism of cancer- and metastasis-initiating cells

    Science.gov (United States)

    Mimeault, Murielle; Batra, Surinder K

    2013-01-01

    Accumulating lines of experimental evidence have revealed that hypoxia-inducible factors, HIF-1α and HIF-2α, are key regulators of the adaptation of cancer- and metastasis-initiating cells and their differentiated progenies to oxygen and nutrient deprivation during cancer progression under normoxic and hypoxic conditions. Particularly, the sustained stimulation of epidermal growth factor receptor (EGFR), insulin-like growth factor-1 receptor (IGF-1R), stem cell factor (SCF) receptor KIT, transforming growth factor-β receptors (TGF-βRs) and Notch and their downstream signalling elements such as phosphatidylinositol 3′-kinase (PI3K)/Akt/molecular target of rapamycin (mTOR) may lead to an enhanced activity of HIFs. Moreover, the up-regulation of HIFs in cancer cells may also occur in the hypoxic intratumoral regions formed within primary and secondary neoplasms as well as in leukaemic cells and metastatic prostate and breast cancer cells homing in the hypoxic endosteal niche of bone marrow. The activated HIFs may induce the expression of numerous gene products such as induced pluripotency-associated transcription factors (Oct-3/4, Nanog and Sox-2), glycolysis- and epithelial-mesenchymal transition (EMT) programme-associated molecules, including CXC chemokine receptor 4 (CXCR4), snail and twist, microRNAs and angiogenic factors such as vascular endothelial growth factor (VEGF). These gene products in turn can play critical roles for high self-renewal ability, survival, altered energy metabolism, invasion and metastases of cancer cells, angiogenic switch and treatment resistance. Consequently, the targeting of HIF signalling network and altered metabolic pathways represents new promising strategies to eradicate the total mass of cancer cells and improve the efficacy of current therapies against aggressive and metastatic cancers and prevent disease relapse. PMID:23301832

  11. Expression and significance of HIF-1α and VEGF in rats with diabetic retinopathy

    Institute of Scientific and Technical Information of China (English)

    Hong-Tao Yan; Guan-Fang Su

    2014-01-01

    Objective:To investigate the expression of hypoxia inducible factor-1α(HIF-1α) and vascular endothelial growth factor(VEGF) in diabetic retinopathy(DR) rats and its effect on theDR occurrence and development.Methods:A total of120SD rats were randomly divided into trial group and control group with60 in each.STZi.p. was used in the trial group to establish theDM model, citrate buffer salt of same amount was usedi.p. to the control group.1,3 and6 months after injection, respective20 rats were sacrificed in each group to observe expression ofHIF-1α andVEGF in the rat retina tissue at different time points.Results:Expression ofHIF-1α andVEGF were negative in the control group; expression ofHIF-1α andVEGF protein in retinal tissue were weak after1 month ofDR mold formation.It showed progressive enhancement along with the progression in different organizations, differences between groups were significant (P<0.05).Conclusions:Expressions ofHIF-1α andVEGF were correlated with disease progression in early diabetic retinopathy.Retinal oxygen can induce over-expression ofHIF-1α andVEGF.It shows thatHIF-1α andVEGF play an important role in the pathogenesis ofDR.

  12. Understanding and exploiting the genomic response to hypoxia

    International Nuclear Information System (INIS)

    Giaccia, A.J.

    2003-01-01

    The tumor microenvironment influences both therapeutic outcome and malignant progression. Of the many factors that may be altered in the tumor microenvironment, changes in tumor oxygenation have been strongly associated with a lower probability of local tumor control and survival. In vitro studies indicate that cells exposed to a low oxygen environment exhibit multiple phenotypes, including cell-cycle arrest, increased expression of pro-angiogenic genes, increased invasive capacity, increased apoptosis, increased anaerobic metabolism and altered differentiation programs. While the mechanistic basis of hypoxia as an impediment to radiotherapy and chemotherapy is well understood, it is unclear what changes in the cellular phenotype are important in understanding how hypoxia modifies malignant progression. One insight into how hypoxia modulates malignant progression comes from understanding the critical transcriptional regulators of gene expression under hypoxic conditions such as hypoxia inducible factor 1 (HIF-1) as well as changes in gene expression in untransformed and transformed cells. Overall, about 1.5% of the genome is found to be transcriptionally responsive to changes in oxygenation. Most importantly, the coordinated changes in gene expression under hypoxic conditions underscore the physiologic basis for altering gene expression in response to a low oxygen environment. In addition, some hypoxia-induced genes exhibit increased expression after reoxygenation, suggesting that they are regulated both by hypoxia and oxidative stress. Analysis of the genomic response to hypoxia has several therapeutic uses. First, it allows one to ask the question of what the cellular consequences are to inhibition of the transcriptional response to hypoxia such as by targeting the HIF-1 transcription factor. While the effect of loss of HIF-1 in tumors leads to inhibition of tumor growth, it does not eliminate tumors. In fact, studies indicate that inhibition of HIF-1 leads to a

  13. Factors regulated by interferon gamma and hypoxia-inducible factor 1A contribute to responses that protect mice from Coccidioides immitis infection

    Directory of Open Access Journals (Sweden)

    Woelk Christopher H

    2012-09-01

    Full Text Available Abstract Background Coccidioidomycosis results from airborne infections caused by either Coccidioides immitis or C. posadasii. Both are pathogenic fungi that live in desert soil in the New World and can infect normal hosts, but most infections are self-limited. Disseminated infections occur in approximately 5% of cases and may prove fatal. Mouse models of the disease have identified strains that are resistant (e.g. DBA/2 or susceptible (e.g. C57BL/6 to these pathogens. However, the genetic and immunological basis for this difference has not been fully characterized. Results Microarray technology was used to identify genes that were differentially expressed in lung tissue between resistant DBA/2 and sensitive C57BL/6 mice after infection with C. immitis. Differentially expressed genes were mapped onto biological pathways, gene ontologies, and protein interaction networks, which revealed that innate immune responses mediated by Type II interferon (i.e., IFNG and the signal transducer and activator of transcription 1 (STAT1 contribute to the resistant phenotype. In addition, upregulation of hypoxia inducible factor 1A (HIF1A, possibly as part of a larger inflammatory response mediated by tumor necrosis factor alpha (TNFA, may also contribute to resistance. Microarray gene expression was confirmed by real-time quantitative PCR for a subset of 12 genes, which revealed that IFNG HIF1A and TNFA, among others, were significantly differentially expressed between the two strains at day 14 post-infection. Conclusion These results confirm the finding that DBA/2 mice express more Type II interferon and interferon stimulated genes than genetically susceptible strains and suggest that differential expression of HIF1A may also play a role in protection.

  14. Triiodothyronine (T3) induces HIF1A and TGFA expression in MCF7 cells by activating PI3K.

    Science.gov (United States)

    Moretto, Fernanda Cristina Fontes; De Sibio, Maria Teresa; Luvizon, Aline Carbonera; Olimpio, Regiane Marques Castro; de Oliveira, Miriane; Alves, Carlos Augusto Barnabe; Conde, Sandro José; Nogueira, Célia Regina

    2016-06-01

    High expression levels of hypoxia inducing factor 1 alpha are related to mammary carcinogenesis. In previous studies, we demonstrated that expression of transforming growth factor alpha increases upon treatment with triiodothyronine, but this expression does not occur in cellular models that do not express the estrogen receptor, or when cells are co-treated with the anti-estrogen, tamoxifen. The aim of this study was to determine the effect of the hormone triiodothyronine on the expression of the genes HIF1A and TGFA in the breast cancer cell line MCF7. The cell line was subjected to treatment with triiodothyronine at the supraphysiological dose of 10(-8)M for 10min, 30min, 1h, and 4h in the presence or absence of actinomycin D, the gene expression inhibitor, cycloheximide, the protein synthesis inhibitor, and LY294002, the phosphoinositide 3 kinase inhibitor. HIF1A and TGFA mRNA expression was analyzed by reverse transcription polymerase chain reaction. For data analysis, we used analysis of variance complemented by Tukey test and an adopted minimum of 5% significance. We found that HIF1A and TGFA expression increased in the presence of triiodothyronine at all times studied. HIF1A expression decreased in triiodothyronine-treated cells when gene transcription was also inhibited; however, TGFA expression decreased after 10 and 30min of treatment even when transcription was not inhibited. We found that activation of PI3K was necessary for triiodothyronine to modulate HIF1A and TGFA expression. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Peritoneal milky spots serve as a hypoxic niche and favor gastric cancer stem/progenitor cell peritoneal dissemination through hypoxia-inducible factor 1α.

    Science.gov (United States)

    Miao, Zhi-Feng; Wang, Zhen-Ning; Zhao, Ting-Ting; Xu, Ying-Ying; Gao, Jian; Miao, Feng; Xu, Hui-Mian

    2014-12-01

    Peritoneal dissemination is the most common cause of death in gastric cancer patients. The hypoxic microenvironment plays a major role in controlling the tumor stem cell phenotype and is associated with patients' prognosis through hypoxia-inducible factor-1α (HIF-1α), a key transcriptional factor that responds to hypoxic stimuli. During the peritoneal dissemination process, gastric cancer stem/progenitor cells (GCSPCs) are thought to enter into and maintained in peritoneal milky spots (PMSs), which have hypoxic microenvironments. However, the mechanism through which the hypoxic environment of PMSs regulated GCSPC maintenance is still poorly understood. Here, we investigated whether hypoxic PMSs were an ideal cancer stem cell niche suitable for GCSPC engraftment. We also evaluated the mechanisms through which the HIF-1α-mediated hypoxic microenvironment regulated GCSPC fate. We observed a positive correlation between HIF-1α expression and gastric cancer peritoneal dissemination (GCPD) in gastric cancer patients. Furthermore, the GCSPC population expanded in primary gastric cancer cells under hypoxic condition in vitro, and hypoxic GCSPCs showed enhanced self-renewal ability, but reduced differentiation capacity, mediated by HIF-1α. In an animal model, GCSPCs preferentially resided in the hypoxic zone of PMSs; moreover, when the hypoxic microenvironment in PMSs was destroyed, GCPD was significantly alleviated. In conclusion, our results demonstrated that PMSs served as a hypoxic niche and favored GCSPCs peritoneal dissemination through HIF-1α both in vitro and in vivo. These results provided new insights into the GCPD process and may lead to advancements in the clinical treatment of gastric cancer. © 2014 The Authors. STEM CELLS Published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.

  16. Hypoxia Induced Factor in Chronic Kidney Disease: Friend or Foe?

    Science.gov (United States)

    Li, Weiying; Zhao, Yuliang; Fu, Ping

    2017-01-01

    Many studies have shown evidence that erythropoiesis-stimulating agents (ESAs), as a classic treatment for chronic kidney disease (CKD)-related anemia, have several disadvantages and may trigger various adverse events with long-term use. The hypoxia-induced factor (HIF) pathway has been intensively investigated in kidney disease, especially in CKD, as research has shown that HIF-mediated erythropoiesis might work as a potential therapeutic strategy for managing CKD-related anemia. Development of prolyl hydroxylase domain inhibitors (PHIs), as an effective HIF activator, is a valuable step toward finding a replacement for ESAs, which showed an effective erythropoiesis through a comprehensive and physiological approach by promoting erythropoietin production, increasing iron bioavailability and improving chronic inflammatory status. Heretofore no adverse events or obvious off-target effects have been reported in clinical trials of PHIs. Nevertheless, a cautious inspection with extended follow-up period is warranted to validate the safety of prolonged HIF elevation, especially considering its ambiguous role in fibrogenesis and inflammation responses and possible risks in accelerating vascular calcification and tumorigenesis. A weighed dosing strategy might be the key to circumvent the unexpected side-effect brought by pleotropic effects of HIF elevation and achieve a selective augmentation of HIF-mediated signaling pathway. New studies with longer follow-up period and adequate analysis about the risks for proinflammation, vascular calcification and tumorigenesis are needed to ensure the drugs are safe for long-term use before being widely accepted in daily clinical practice.

  17. The dietary flavonoid kaempferol effectively inhibits HIF-1 activity and hepatoma cancer cell viability under hypoxic conditions

    International Nuclear Information System (INIS)

    Mylonis, Ilias; Lakka, Achillia; Tsakalof, Andreas; Simos, George

    2010-01-01

    Research highlights: → Kaempferol inhibits HIF-1 activity in hepatocarcinoma cells; → Kaempferol causes cytoplasmic mislocalization of HIF-1α by impairing the MAPK pathway. → Viability of hepatocarcinoma cells under hypoxia is reduced by kaempferol. -- Abstract: Hepatocellular carcinoma (HCC) is characterized by high mortality rates and resistance to conventional treatment. HCC tumors usually develop local hypoxia, which stimulates proliferation of cancer cells and renders them resilient to chemotherapy. Adaptation of tumor cells to the hypoxic conditions depends on the hypoxia-inducible factor 1 (HIF-1). Over-expression of its regulated HIF-1α subunit, an important target of anti-cancer therapy, is observed in many cancers including HCC and is associated with severity of tumor growth and poor patient prognosis. In this report we investigate the effect of the dietary flavonoid kaempferol on activity, expression levels and localization of HIF-1α as well as viability of human hepatoma (Huh7) cancer cells. Treatment of Huh7 cells with kaempferol under hypoxic conditions (1% oxygen) effectively inhibited HIF-1 activity in a dose-dependent manner (IC 50 = 5.16 μM). The mechanism of this inhibition did not involve suppression of HIF-1α protein levels but rather its mislocalization into the cytoplasm due to inactivation of p44/42 MAPK by kaempferol (IC 50 = 4.75 μM). Exposure of Huh7 cells to 10 μΜ kaempferol caused significant reduction of their viability, which was remarkably more evident under hypoxic conditions. In conclusion, kaempferol, a non-toxic natural food component, inhibits both MAPK and HIF-1 activity at physiologically relevant concentrations (5-10 μM) and suppresses hepatocarcinoma cell survival more efficiently under hypoxia. It has, therefore, potential as a therapeutic or chemopreventive anti-HCC agent.

  18. The dietary flavonoid kaempferol effectively inhibits HIF-1 activity and hepatoma cancer cell viability under hypoxic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mylonis, Ilias; Lakka, Achillia; Tsakalof, Andreas [Laboratory of Biochemistry, School of Medicine, University of Thessaly, BIOPOLIS, 41110 Larissa (Greece); Institute of Biomedical Research and Technology (BIOMED), 51 Papanastasiou str., 41222 Larissa (Greece); Simos, George, E-mail: simos@med.uth.gr [Laboratory of Biochemistry, School of Medicine, University of Thessaly, BIOPOLIS, 41110 Larissa (Greece); Institute of Biomedical Research and Technology (BIOMED), 51 Papanastasiou str., 41222 Larissa (Greece)

    2010-07-16

    Research highlights: {yields} Kaempferol inhibits HIF-1 activity in hepatocarcinoma cells; {yields} Kaempferol causes cytoplasmic mislocalization of HIF-1{alpha} by impairing the MAPK pathway. {yields} Viability of hepatocarcinoma cells under hypoxia is reduced by kaempferol. -- Abstract: Hepatocellular carcinoma (HCC) is characterized by high mortality rates and resistance to conventional treatment. HCC tumors usually develop local hypoxia, which stimulates proliferation of cancer cells and renders them resilient to chemotherapy. Adaptation of tumor cells to the hypoxic conditions depends on the hypoxia-inducible factor 1 (HIF-1). Over-expression of its regulated HIF-1{alpha} subunit, an important target of anti-cancer therapy, is observed in many cancers including HCC and is associated with severity of tumor growth and poor patient prognosis. In this report we investigate the effect of the dietary flavonoid kaempferol on activity, expression levels and localization of HIF-1{alpha} as well as viability of human hepatoma (Huh7) cancer cells. Treatment of Huh7 cells with kaempferol under hypoxic conditions (1% oxygen) effectively inhibited HIF-1 activity in a dose-dependent manner (IC{sub 50} = 5.16 {mu}M). The mechanism of this inhibition did not involve suppression of HIF-1{alpha} protein levels but rather its mislocalization into the cytoplasm due to inactivation of p44/42 MAPK by kaempferol (IC{sub 50} = 4.75 {mu}M). Exposure of Huh7 cells to 10 {mu}{Mu} kaempferol caused significant reduction of their viability, which was remarkably more evident under hypoxic conditions. In conclusion, kaempferol, a non-toxic natural food component, inhibits both MAPK and HIF-1 activity at physiologically relevant concentrations (5-10 {mu}M) and suppresses hepatocarcinoma cell survival more efficiently under hypoxia. It has, therefore, potential as a therapeutic or chemopreventive anti-HCC agent.

  19. Expression of hypoxia-induced factor-1 alpha in early-stage and in metastatic oral squamous cell carcinoma.

    Science.gov (United States)

    Ribeiro, Maisa; Teixeira, Sarah R; Azevedo, Monarko N; Fraga, Ailton C; Gontijo, Antônio Pm; Vêncio, Eneida F

    2017-04-01

    To investigate hypoxia-induced factor-1 alpha expression in distinct oral squamous cell carcinoma subtypes and topographies and correlate with clinicopathological data. Hypoxia-induced factor-1 alpha expression was assessed by immunohistochemistry in 93 cases of OSCC. Clinical and histopathological data were reviewed from medical records. Hypoxia-induced factor-1 alpha status was distinct according to tumor location, subtype and topography affect. In superficial oral squamous cell carcinomas, most tumor cells overexpressed hypoxia-induced factor-1 alpha, whereas hypoxia-induced factor-1 alpha was restricted to the intratumoral region in conventional squamous cell carcinomas. All basaloid squamous cell carcinomas exhibited downregulation of hypoxia-induced factor-1 alpha. Interestingly, metastatic lymph nodes (91.7%, p = 0.001) and the intratumoral regions of corresponding primary tumors (58.3%, p = 0.142) showed hypoxia-induced factor-1 alpha-positive tumor cells. Overall survival was poor in patients with metastatic lymph nodes. Hypoxia-induced factor-1 alpha has distinct expression patterns in different oral squamous cell carcinoma subtypes and topographies, suggesting that low oxygen tension promotes the growth pattern of superficial and conventional squamous cell carcinoma, but not basaloid squamous cell carcinoma. Indeed, a hypoxic environment may facilitate regional metastasis, making it a useful diagnostic and prognostic marker in primary tumors.

  20. Metabolic profiling reveals potential metabolic markers associated with Hypoxia Inducible Factor-mediated signalling in hypoxic cancer cells.

    Science.gov (United States)

    Armitage, Emily G; Kotze, Helen L; Allwood, J William; Dunn, Warwick B; Goodacre, Royston; Williams, Kaye J

    2015-10-28

    Hypoxia inducible factors (HIFs) plays an important role in oxygen compromised environments and therefore in tumour survival. In this research, metabolomics has been applied to study HIFs metabolic function in two cell models: mouse hepatocellular carcinoma and human colon carcinoma, whereby the metabolism has been profiled for a range of oxygen potentials. Wild type cells have been compared to cells deficient in HIF signalling to reveal its effect on cellular metabolism under normal oxygen conditions as well as low oxygen, hypoxic and anoxic environments. Characteristic responses to hypoxia that were conserved across both cell models involved the anti-correlation between 2-hydroxyglutarate, 2-oxoglutarate, fructose, hexadecanoic acid, hypotaurine, pyruvate and octadecenoic acid with 4-hydroxyproline, aspartate, cysteine, glutamine, lysine, malate and pyroglutamate. Further to this, network-based correlation analysis revealed HIF specific pathway responses to each oxygen condition that were also conserved between cell models. From this, 4-hydroxyproline was revealed as a regulating hub in low oxygen survival of WT cells while fructose appeared to be in HIF deficient cells. Pathways surrounding these hubs were built from the direct connections of correlated metabolites that look beyond traditional pathways in order to understand the mechanism of HIF response to low oxygen environments.

  1. HIF-1? Is Essential for Effective PMN Bacterial Killing, Antimicrobial Peptide Production and Apoptosis in Pseudomonas aeruginosa Keratitis

    OpenAIRE

    Berger, Elizabeth A.; McClellan, Sharon A.; Vistisen, Kerry S.; Hazlett, Linda D.

    2013-01-01

    Hypoxia-inducible factor (HIF)-1α, is a transcription factor that controls energy metabolism and angiogenesis under hypoxic conditions, and a potent regulator of innate immunity. The studies described herein examined the role of HIF-1α in disease resolution in BALB/c (resistant, cornea heals) mice after ocular infection with Pseudomonas (P.) aeruginosa. Furthermore, the current studies focused on the neutrophil (PMN), the predominant cell infiltrate in keratitis. Using both siRNA and an antag...

  2. ECM-dependent HIF induction directs trophoblast stem cell fate via LIMK1-mediated cytoskeletal rearrangement.

    Directory of Open Access Journals (Sweden)

    Hwa J Choi

    Full Text Available The Hypoxia-inducible Factor (HIF family of transcriptional regulators coordinates the expression of dozens of genes in response to oxygen deprivation. Mammalian development occurs in a hypoxic environment and HIF-null mice therefore die in utero due to multiple embryonic and placental defects. Mouse embryonic stem cells do not differentiate into placental cells; therefore, trophoblast stem cells (TSCs are used to study mouse placental development. Consistent with a requirement for HIF activity during placental development in utero, TSCs derived from HIF-null mice exhibit severe differentiation defects and fail to form trophoblast giant cells (TGCs in vitro. Interestingly, differentiating TSCs induce HIF activity independent of oxygen tension via unclear mechanisms. Here, we show that altering the extracellular matrix (ECM composition upon which TSCs are cultured changes their differentiation potential from TGCs to multinucleated syncytiotropholasts (SynTs and blocks oxygen-independent HIF induction. We further find that modulation of Mitogen Activated Protein Kinase Kinase-1/2 (MAP2K1/2, MEK-1/2 signaling by ECM composition is responsible for this effect. In the absence of ECM-dependent cues, hypoxia-signaling pathways activate this MAPK cascade to drive HIF induction and redirect TSC fate along the TGC lineage. In addition, we show that integrity of the microtubule and actin cytoskeleton is critical for TGC fate determination. HIF-2α ensures TSC cytoskeletal integrity and promotes invasive TGC formation by interacting with c-MYC to induce non-canonical expression of Lim domain kinase 1-an enzyme that regulates microtubule and actin stability, as well as cell invasion. Thus, we find that HIF can integrate positional and metabolic cues from within the TSC niche to regulate placental development by modulating the cellular cytoskeleton via non-canonical gene expression.

  3. Alpha5 nicotinic acetylcholine receptor mediates nicotine-induced HIF-1α and VEGF expression in non-small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xiaoli; Jia, Yanfei; Zu, Shanshan [Central Laboratory, Jinan Central Hospital Affiliated to Shandong University, Jinan 250013 (China); Li, Ruisheng [Institute of Infectious Diseases, 302 Military Hospital, Beijing 100039 (China); Jia, Ying; Zhao, Yun; Xiao, Dongjie [Central Laboratory, Jinan Central Hospital Affiliated to Shandong University, Jinan 250013 (China); Dang, Ningning [Department of Dermatology, Jinan Central Hospital Affiliated to Shandong University, Jinan 250013 (China); Wang, Yunshan [Central Laboratory, Jinan Central Hospital Affiliated to Shandong University, Jinan 250013 (China)

    2014-07-15

    By binding to nicotinic acetylcholine receptors (nAChRs), nicotine induces the proliferation and apoptosis of non-small cell lung cancer (NSCLC). Previous studies have indicated that α5-nAChR is highly associated with lung cancer risk and nicotine dependence. However, the mechanisms through which α5-nAChRs may influence lung carcinogenesis are far from clear. In the present study, we investigated the roles of α5-nAChR in the nicotine-induced expression of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF). Immunohistochemistry was used to detect the expression of α5-nAChR and HIF-1α in 60 specimens of lung cancer and para-carcinoma tissue. The correlations between the expression levels of α5-nAChR and HIF-1α and other clinicopathological data were analyzed. In a cell line that highly expressed α5-nAChR, the loss of α5-nAChR function by siRNA was used to study whether α5-nAChR is involved in the nicotine-induced expression of HIF-1α and VEGF through the activation of the ERK1/2 and PI3K/Akt signaling pathways. Cell growth was detected using the cell counting kit-8 (CCK-8). α5-nAChR (78.3%) and HIF-1α (88.3%) were both overexpressed in NSCLC, and their expression levels were found to be correlated with each other (P < 0.05). In the A549 cell line, α5-nAChR and HIF-1α were found to be expressed under normal conditions, and their expression levels were significantly increased in response to nicotine treatment. The silencing of α5-nAChR significantly inhibited the nicotine-induced cell proliferation compared with the control group and attenuated the nicotine-induced upregulation of HIF-1α and VEGF, and these effects required the cooperation of the ERK1/2 and PI3K/Akt signaling pathways. These results show that the α5-nAChR/HIF-1α/VEGF axis is involved in nicotine-induced tumor cell proliferation, which suggests that α5-nAChR may serve as a potential anticancer target in nicotine-associated lung cancer. - Highlights

  4. Alpha5 nicotinic acetylcholine receptor mediates nicotine-induced HIF-1α and VEGF expression in non-small cell lung cancer

    International Nuclear Information System (INIS)

    Ma, Xiaoli; Jia, Yanfei; Zu, Shanshan; Li, Ruisheng; Jia, Ying; Zhao, Yun; Xiao, Dongjie; Dang, Ningning; Wang, Yunshan

    2014-01-01

    By binding to nicotinic acetylcholine receptors (nAChRs), nicotine induces the proliferation and apoptosis of non-small cell lung cancer (NSCLC). Previous studies have indicated that α5-nAChR is highly associated with lung cancer risk and nicotine dependence. However, the mechanisms through which α5-nAChRs may influence lung carcinogenesis are far from clear. In the present study, we investigated the roles of α5-nAChR in the nicotine-induced expression of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF). Immunohistochemistry was used to detect the expression of α5-nAChR and HIF-1α in 60 specimens of lung cancer and para-carcinoma tissue. The correlations between the expression levels of α5-nAChR and HIF-1α and other clinicopathological data were analyzed. In a cell line that highly expressed α5-nAChR, the loss of α5-nAChR function by siRNA was used to study whether α5-nAChR is involved in the nicotine-induced expression of HIF-1α and VEGF through the activation of the ERK1/2 and PI3K/Akt signaling pathways. Cell growth was detected using the cell counting kit-8 (CCK-8). α5-nAChR (78.3%) and HIF-1α (88.3%) were both overexpressed in NSCLC, and their expression levels were found to be correlated with each other (P < 0.05). In the A549 cell line, α5-nAChR and HIF-1α were found to be expressed under normal conditions, and their expression levels were significantly increased in response to nicotine treatment. The silencing of α5-nAChR significantly inhibited the nicotine-induced cell proliferation compared with the control group and attenuated the nicotine-induced upregulation of HIF-1α and VEGF, and these effects required the cooperation of the ERK1/2 and PI3K/Akt signaling pathways. These results show that the α5-nAChR/HIF-1α/VEGF axis is involved in nicotine-induced tumor cell proliferation, which suggests that α5-nAChR may serve as a potential anticancer target in nicotine-associated lung cancer. - Highlights

  5. Experimental study of the correlation between 99Tcm-EC-MNZ SPECT imaging and the expression of hypoxia inducible factor-1α in tumor tissuse

    International Nuclear Information System (INIS)

    Chen Jie; Lu Xueguan; Tang Jun; Fan Wo

    2005-01-01

    Objective: To evaluate the correlation between 99 Tc m -ethylene dicysteinc-metronidazaole ( 99 Tc M -EC-MNZ) SPECT imaging and the expression of hypoxia inducible factor-1α (HIF-1α) in tumor tissue. Methods: Twelve S180 sarcoma-bearing Kunming mice tumor models were established. Hypoxic imaging was obtained by SPECT with 99 Tc m -EC-MNZ and the corresponding tumor/muscle ratios (T/M) were measured. Then the animals were sacrificed and the tumor specimen was resected, the expression of HIF-1α and vascular endothelial growth factor (VEGF) was measured by immunohistochemistry. Results: Three hours after injection of 99 Tc m -EC-MNZ, the T/M ranged from 1.93 to 4.46 (median 3.13). The expression of HIF-1α ranged from 31.2% to 60.8% (median 50.4%) and was linearly correlated with the T/M (t=2.732, r=0.654, P=0.021). The expression of VEGF ranged from 33.8% to 57.5% (median 53.1%) and also linearly correlated with the expression of HIF-1α (t=3.011, r=0.690, P=0.0131). Conclusions: There is linear correlation between 99 Tc m -EC-MNZ hypoxic SPECT imaging and the expression of HIF-1α. Combining them can reliably reflect the hypoxic status of the tumor. (authors)

  6. Hypoxic Preconditioning Promotes the Bioactivities of Mesenchymal Stem Cells via the HIF-1α-GRP78-Akt Axis.

    Science.gov (United States)

    Lee, Jun Hee; Yoon, Yeo Min; Lee, Sang Hun

    2017-06-21

    Mesenchymal stem cells (MSC) are ideal materials for stem cell-based therapy. As MSCs reside in hypoxic microenvironments (low oxygen tension of 1% to 7%), several studies have focused on the beneficial effects of hypoxic preconditioning on MSC survival; however, the mechanisms underlying such effects remain unclear. This study aimed to uncover the potential mechanism involving 78-kDa glucose-regulated protein (GRP78) to explain the enhanced MSC bioactivity and survival in hindlimb ischemia. Under hypoxia (2% O₂), the expression of GRP78 was significantly increased via hypoxia-inducible factor (HIF)-1α. Hypoxia-induced GRP78 promoted the proliferation and migration potential of MSCs through the HIF-1α-GRP78-Akt signal axis. In a murine hind-limb ischemia model, hypoxic preconditioning enhanced the survival and proliferation of transplanted MSCs through suppression of the cell death signal pathway and augmentation of angiogenic cytokine secretion. These effects were regulated by GRP78. Our findings indicate that hypoxic preconditioning promotes survival, proliferation, and angiogenic cytokine secretion of MSCs via the HIF-1α-GRP78-Akt signal pathway, suggesting that hypoxia-preconditioned MSCs might provide a therapeutic strategy for MSC-based therapies and that GRP78 represents a potential target for the development of functional MSCs.

  7. CD44 Interacts with HIF-2α to Modulate the Hypoxic Phenotype of Perinecrotic and Perivascular Glioma Cells

    DEFF Research Database (Denmark)

    Johansson, Elinn; Grassi, Elisa S.; Pantazopoulou, Vasiliki

    2017-01-01

    Hypoxia-inducible factors enhance glioma stemness, and glioma stem cells have an amplified hypoxic response despite residing within a perivascular niche. Still, little is known about differential HIF regulation in stem versus bulk glioma cells. We show that the intracellular domain of stem cell...... marker CD44 (CD44ICD) is released at hypoxia, binds HIF-2α (but not HIF-1α), enhances HIF target gene activation, and is required for hypoxia-induced stemness in glioma. In a glioma mouse model, CD44 was restricted to hypoxic and perivascular tumor regions, and in human glioma, a hypoxia signature...... correlated with CD44. The CD44ICD was sufficient to induce hypoxic signaling at perivascular oxygen tensions, and blocking CD44 cleavage decreased HIF-2α stabilization in CD44-expressing cells. Our data indicate that the stem cell marker CD44 modulates the hypoxic response of glioma cells and that the pseudo-hypoxic...

  8. Apigenin ameliorates hypertension-induced cardiac hypertrophy and down-regulates cardiac hypoxia inducible factor-lα in rats.

    Science.gov (United States)

    Zhu, Zeng-Yan; Gao, Tian; Huang, Yan; Xue, Jie; Xie, Mei-Lin

    2016-04-01

    Apigenin is a natural flavonoid compound that can inhibit hypoxia-inducible factor (HIF)-1α expression in cultured tumor cells under hypoxic conditions. Hypertension-induced cardiac hypertrophy is always accompanied by abnormal myocardial glucolipid metabolism due to an increase of HIF-1α. However, whether or not apigenin may ameliorate the cardiac hypertrophy and abnormal myocardial glucolipid metabolism remains unknown. This study aimed to examine the effects of apigenin. Rats with cardiac hypertrophy induced by renovascular hypertension were treated with apigenin 50-100 mg kg(-1) (the doses can be achieved by pharmacological or dietary supplementation for an adult person) by gavage for 4 weeks. The results showed that after treatment with apigenin, the blood pressure, heart weight, heart weight index, cardiomyocyte cross-sectional area, serum angiotensin II, and serum and myocardial free fatty acids were reduced. It is important to note that apigenin decreased the expression level of myocardial HIF-1α protein. Moreover, apigenin simultaneously increased the expression levels of myocardial peroxisome proliferator-activated receptor (PPAR) α, carnitine palmitoyltransferase (CPT)-1, and pyruvate dehydrogenase kinase (PDK)-4 proteins and decreased the expression levels of myocardial PPARγ, glycerol-3-phosphate acyltransferase genes (GPAT), and glucose transporter (GLUT)-4 proteins. These findings demonstrated that apigenin could improve hypertensive cardiac hypertrophy and abnormal myocardial glucolipid metabolism in rats, and its mechanisms might be associated with the down-regulation of myocardial HIF-1α expression and, subsequently increasing the expressions of myocardial PPARα and its target genes CPT-1 and PDK-4, and decreasing the expressions of myocardial PPARγ and its target genes GPAT and GLUT-4.

  9. A preclinical model for noninvasive imaging of hypoxia-induced gene expression; comparison with an exogenous marker of tumor hypoxia

    Energy Technology Data Exchange (ETDEWEB)

    Wen Bixiu; Burgman, Paul; Zanzonico, Pat; O' Donoghue, Joseph; Li, Gloria C.; Ling, C. Clifton [Memorial Sloan-Kettering Cancer Center, Department of Medical Physics, New York (United States); Cai Shangde; Finn, Ron [Memorial Sloan-Kettering Cancer Center, Department of Radiology, New York (United States); Serganova, Inna [Memorial Sloan-Kettering Cancer Center, Department of Neurology, New York (United States); Blasberg, Ronald; Gelovani, Juri [Memorial Sloan-Kettering Cancer Center, Department of Radiology, New York (United States); Memorial Sloan-Kettering Cancer Center, Department of Neurology, New York (United States)

    2004-11-01

    Hypoxia is associated with tumor aggressiveness and is an important cause of resistance to radiation therapy and chemotherapy. Assays of tumor hypoxia could provide selection tools for hypoxia-modifying treatments. The purpose of this study was to develop and characterize a rodent tumor model with a reporter gene construct that would be transactivated by the hypoxia-inducible molecular switch, i.e., the upregulation of HIF-1. The reporter gene construct is the herpes simplex virus 1-thymidine kinase (HSV1-tk) fused with the enhanced green fluorescent protein (eGFP) under the regulation of an artificial hypoxia-responsive enhancer/promoter. In this model, tumor hypoxia would up-regulate HIF-1, and through the hypoxia-responsive promoter transactivate the HSV1-tkeGFPfusion gene. The expression of this reporter gene can be assessed with the {sup 124}I-labeled reporter substrate 2'-fluoro-2'-deoxy-1-{beta}-d-arabinofuranosyl-5-iodouracil ({sup 124}I-FIAU), which is phosphorylated by the HSV1-tk enzyme and trapped in the hypoxic cells. Animal positron emission tomography (microPET) and phosphor plate imaging (PPI) were used in this study to visualize the trapped {sup 124}I-FIAU, providing a distribution of the hypoxia-induced molecular events. The distribution of {sup 124}I-FIAU was also compared with that of an exogenous hypoxic cell marker, {sup 18}F-fluoromisonidazole (FMISO). Our results showed that {sup 124}I-FIAU microPET imaging of the hypoxia-induced reporter gene expression is feasible, and that the intratumoral distributions of {sup 124}I-FIAU and {sup 18}F-FMISO are similar. In tumor sections, detailed radioactivity distributions were obtained with PPI which also showed similarity between {sup 124}I-FIAU and {sup 18}F-FMISO. This reporter system is sufficiently sensitive to detect hypoxia-induced transcriptional activation by noninvasive imaging and might provide a valuable tool in studying tumor hypoxia and in validating existing and future

  10. Hypoxia-induced secretion of TGF-β1 in mesenchymal stem cell promotes breast cancer cell progression.

    Science.gov (United States)

    Hung, Shun-Pei; Yang, Muh-Hwa; Tseng, Kuo-Fung; Lee, Oscar K

    2013-01-01

    In solid tumors, a decreased oxygen and nutrient supply creates a hypoxic microenvironment in the central region. This hypoxic condition induces molecular responses of normal and cancer cells in the local area, including angiogenesis, metabolic changes, and metastasis. In addition, other cells including mesenchymal stem cells (MSCs) have been reported to be recruited into the hypoxic area of solid tumors. In our previous study, we found that hypoxic condition induces the secretion of growth factors and cytokines in MSCs, and here we demonstrate that elevated secretion of transforming growth factor1 (TGF-β1) by MSCs under hypoxia promotes the growth, motility, and invasive ability of breast cancer cells. It was found that TGF-β1 promoter activity was regulated by hypoxia, and the major hypoxia-regulated element was located between bp -1030 to -666 in front of the TGF-β1 promoter region. In ChIP assay, the results revealed that HIF-1 was bound to the hypoxia response element (HRE) of TGF-β1 promoter. Collectively, the results indicate that hypoxia microenvironment can enhance cancer cell growth through the paracrine effects of the MSCs by driving their TGF-β1 gene expression and secretion. Therefore, extra caution has to be exercised when considering hypoxia pretreatment of MSCs before cell transplantation into patients for therapeutic purposes, particularly in patients susceptible to tumor growth.

  11. Minoxidil Induction of VEGF Is Mediated by Inhibition of HIF-Prolyl Hydroxylase

    Science.gov (United States)

    Yum, Soohwan; Jeong, Seongkeun; Kim, Dohoon; Lee, Sunyoung; Kim, Wooseong; Yoo, Jin-Wook; Kwon, Oh Sang; Kim, Dae-Duk; Min, Do Sik; Jung, Yunjin

    2017-01-01

    The topical application of minoxidil may achieve millimolar concentrations in the skin. We investigated whether millimolar minoxidil could induce vascular endothelial growth factor (VEGF), a possible effector for minoxidil-mediated hair growth, and how it occurred at the molecular level. Cell-based experiments were performed to investigate a molecular mechanism underlying the millimolar minoxidil induction of VEGF. The inhibitory effect of minoxidil on hypoxia-inducible factor (HIF) prolyl hydroxylase-2 (PHD-2) was tested by an in vitro von Hippel–Lindau protein (VHL) binding assay. To examine the angiogenic potential of millimolar minoxidil, a chorioallantoic membrane (CAM) assay was used. In human keratinocytes and dermal papilla cells, millimolar minoxidil increased the secretion of VEGF, which was not attenuated by a specific adenosine receptor antagonist that inhibits the micromolar minoxidil induction of VEGF. Millimolar minoxidil induced hypoxia-inducible factor-1α (HIF-1α), and the induction of VEGF was dependent on HIF-1. Moreover, minoxidil applied to the dorsal area of mice increased HIF-1α and VEGF in the skin. In an in vitro VHL binding assay, minoxidil directly inhibited PHD-2, thus preventing the hydroxylation of cellular HIF-1α and VHL-dependent proteasome degradation and resulting in the stabilization of HIF-1α protein. Minoxidil inhibition of PHD-2 was reversed by ascorbate, a cofactor of PHD-2, and the minoxidil induction of cellular HIF-1α was abrogated by the cofactor. Millimolar minoxidil promoted angiogenesis in the CAM assay, an in vivo angiogenic test, and this was nullified by the specific inhibition of VEGF. Our data demonstrate that PHD may be the molecular target for millimolar minoxidil-mediated VEGF induction via HIF-1. PMID:29295567

  12. SIRT3 opposes reprogramming of cancer cell metabolism through HIF1α destabilization

    Science.gov (United States)

    Finley, Lydia W.S.; Carracedo, Arkaitz; Lee, Jaewon; Souza, Amanda; Egia, Ainara; Zhang, Jiangwen; Teruya-Feldstein, Julie; Moreira, Paula I.; Cardoso, Sandra M.; Clish, Clary B.; Pandolfi, Pier Paolo; Haigis, Marcia C.

    2011-01-01

    Summary Tumor cells exhibit aberrant metabolism characterized by high glycolysis even in the presence of oxygen. This metabolic reprogramming, known as the Warburg effect, provides tumor cells with the substrates required for biomass generation. Here, we show that the mitochondrial NAD-dependent deacetylase SIRT3 is a crucial regulator of the Warburg effect. Mechanistically, SIRT3 mediates metabolic reprogramming by destabilizing hypoxia-inducible factor-1α (HIF1α), a transcription factor that controls glycolytic gene expression. SIRT3 loss increases reactive oxygen species production, leading to HIF1α stabilization. SIRT3 expression is reduced in human breast cancers, and its loss correlates with the upregulation of HIF1α target genes. Finally, we find that SIRT3 overexpression represses glycolysis and proliferation in breast cancer cells, providing a metabolic mechanism for tumor suppression. PMID:21397863

  13. The role of hypoxia-induced factor in the regulation of oxygen homeostasis during reparative regeneration in compromised microcirculation

    Directory of Open Access Journals (Sweden)

    S. G. Izmaylov

    2017-01-01

    Full Text Available The aim of the present review is to find an answer to the clinically important question on the mechanisms regulating the activity of reparative regeneration in hypoxic conditions and potential ways to modify this process. In the recent studies, compensated hypoxia is characterized as a trigger for the regeneration, with the central regulating factor being the member of the cytokine family, hypoxia-inducible factor-1 (HIF-1. Changes in the concentration of this protein modulates cell migration, angiogenesis and epithelialmesenchymal integration; it also stimulates the proliferation of endothelial cells and fibroblasts, playing a  major role in the stimulation of wound healing, especially with compromised microcirculation, for example, diabetes mellitus. 

  14. Inhibition of HIF-1α decreases expression of pro-inflammatory IL-6 and TNF-α in diabetic retinopathy.

    Science.gov (United States)

    Gao, Xiuhua; Li, Yonghua; Wang, Hongxia; Li, Chuanbao; Ding, Jianguang

    2017-12-01

    Recent studies demonstrate that pro-inflammatory cytokines (PICs, i.e. IL-1β, IL-6 and TNF-α) in retinal tissues are likely involved in the development of diabetic retinopathy (DR). In this report, we particularly examined contributions of hypoxia inducible factor subtype 1α (HIF-1α) to the expression of PICs and their receptors in diabetic retina. Streptozotocin (STZ) was systemically injected to induce hyperglycaemia in rats. ELISA and Western blot analysis were employed to determine the levels of HIF-1α and PICs as well as PIC receptors in retinal tissues of control rats and STZ rats. The levels of retinal HIF-1α were significantly increased in STZ rats 4-10 weeks after induction of hyperglycaemia as compared with control animals. With increasing HIF-1α retinal PICs including IL-1β, IL-6 and TNF-α, their respective receptors, namely IL-1R, IL-6R and TNFR1, were also elevated in STZ rats. Moreover, inhibition of HIF-1α by injection of 2-methoxyestradiol (2-MET) significantly decreased the amplified expression IL-6, TNF-α, IL-6R and TNFR1 in diabetic retina, but did not modify IL-1β pathway. In addition, we examined protein expression of Caspase-3 indicating cell apoptosis in the retina of STZ rats after infusing 2-MET, demonstrating that 2-MET attenuated an increase in Caspase-3 evoked by STZ. Hypoxia inducible factor subtype 1α (HIF-1α) activated in diabetic retina is likely to play a role in regulating pathophysiological process via IL-6 and TNF-α mechanism. This has pharmacological implications to target specific HIF-1α, IL-6 and TNF-α signalling pathway for dysfunction and vulnerability related to DR. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  15. Telomere elongation protects heart and lung tissue cells from fatal damage in rats exposed to severe hypoxia.

    Science.gov (United States)

    Wang, Yaping; Zhao, Zhen; Zhu, Zhiyong; Li, Pingying; Li, Xiaolin; Xue, Xiaohong; Duo, Jie; Ma, Yingcai

    2018-02-17

    The effects of acute hypoxia at high altitude on the telomere length of the cells in the heart and lung tissues remain unclear. This study aimed to investigate the change in telomere length of rat heart and lung tissue cells in response to acute exposure to severe hypoxia and its role in hypoxia-induced damage to heart and lung tissues. Forty male Wistar rats (6-week old) were randomized into control group (n = 10) and hypoxia group (n = 30). Rats in control group were kept at an altitude of 1500 m, while rats in hypoxia group were exposed to simulated hypoxia with an altitude of 5000 m in a low-pressure oxygen chamber for 1, 3, and 7 days (n = 10). The left ventricular and right middle lobe tissues of each rat were collected for measurement of telomere length and reactive oxygen species (ROS) content, and the mRNA and protein levels of telomerase reverse transcriptase (TERT), hypoxia-inducible factor1α (HIF-1α), and hypoxia-inducible factor1α (HIF-2α). Increased exposure to hypoxia damaged rat heart and lung tissue cells and increased ROS production and telomere length. The mRNA and protein levels of TERT and HIF-1α were significantly higher in rats exposed to hypoxia and increased with prolonged exposure; mRNA and protein levels of HIF-2α increased only in rats exposed to hypoxia for 7 days. TERT was positively correlated with telomere length and the levels of HIF-1α but not HIF-2α. Acute exposure to severe hypoxia causes damage to heart and lung tissues due to the production of ROS but promotes telomere length and adaptive response by upregulating TERT and HIF-1α, which protect heart and lung tissue cells from fatal damage.

  16. S1P prophylaxis mitigates acute hypobaric hypoxia-induced molecular, biochemical, and metabolic disturbances: A preclinical report.

    Science.gov (United States)

    Chawla, Sonam; Rahar, Babita; Saxena, Shweta

    2016-05-01

    Sphingosine-1-phosphate (S1P) is emerging to have hypoxic preconditioning potential in various preclinical studies. The study aims to evaluate the preclinical preconditioning efficacy of exogenously administered S1P against acute hypobaric hypoxia (HH)-induced pathological disturbances. Male Sprague Dawley rats (200 ± 20 g) were preconditioned with 1, 10, and 100 μg/kg body weight (b.w.) S1P (i.v.) for three consecutive days. On the third day, S1P preconditioned animals, along with hypoxia control animals, were exposed to HH equivalent to 7,620 m (280 mm Hg) for 6 h. Postexposure status of cardiac energy production, circulatory vasoactive mediators, pulmonary and cerebral oxidative damage, and inflammation were assessed. HH exposure led to cardiac energy deficit indicated by low ATP levels and pronounced AMPK activation levels, raised circulatory levels of brain natriuretic peptide and endothelin-1 with respect to total nitrate (NOx), redox imbalance, inflammation, and alterations in NOx levels in the pulmonary and cerebral tissues. These pathological precursors have been routinely reported to be coincident with high-altitude diseases. Preconditioning with S1P, especially 1 µg/kg b.w. dose, was seen to reverse the manifestation of these pathological disturbances. The protective efficacy could be attributed, at least in part, to enhanced activity of cardioprotective protein kinase C and activation of small GTPase Rac1, which led to further induction of hypoxia-adaptive molecular mediators: hypoxia-inducible factor (HIF)-1α and Hsp70. This is a first such report, to the best of our knowledge, elucidating the mechanism of exogenous S1P-mediated HIF-1α/Hsp70 induction. Conclusively, systemic preconditioning with 1 μg/kg b.w. S1P in rats protects against acute HH-induced pathological disturbances. © 2016 IUBMB Life 68(5):365-375, 2016. © 2016 International Union of Biochemistry and Molecular Biology.

  17. Limitation of HIF-1α with pentoxifillyne on renal tubular ischemia result of hiperoxaluria and ESWL.

    Science.gov (United States)

    Erturhan, Sakip; Bayrak, Omer; Seckiner, Ilker; Celik, Mehmet; Karakok, Metin

    2014-03-01

    To evaluate hypoxia-inducible factor 1 subunit α (HIF-1α) expression during the performance of extracorporeal shock wave lithotripsy (ESWL) and to investigate the effects of pentoxyphylline on HIF-1α expression. One hundred New Zealand Albino rabbit were used in the study divided in 5 groups. There were 20 rabbits in each group. The groups were divided in two parts: early (7 days) and late period (14 days) according to follow up duration. Immunohistochemical analyses were performed using nuclear staining to show HIF-1α expression in rabbit renal tissue sample. HIF-1α expression was higher in rabbits undergoing ESWL (group 4). In the hyperoxaluria group taking pentoxyphylline before ESWL (group 5), HIF-1α expression was lower in both early and late period subgroups (p ESWL may cause renal cell injury. Our results suggest that pentoxyphylline, as a circulatory regulator agent, may prevent renal cell injury induced by ESWL.

  18. Cytoprotective effects of fisetin against hypoxia-induced cell death in PC12 cells.

    Science.gov (United States)

    Chen, Pei-Yi; Ho, Yi-Ru; Wu, Ming-Jiuan; Huang, Shun-Ping; Chen, Po-Kong; Tai, Mi-Hsueh; Ho, Chi-Tang; Yen, Jui-Hung

    2015-01-01

    Fisetin (3,7,3',4'-tetrahydroxyflavone), a flavonol compound of flavonoids, exhibits a broad spectrum of biological activities including anti-oxidant, anti-inflammatory, anti-cancer and neuroprotective effects. The aim of this study is to investigate the cytoprotective effect of fisetin and the underlying molecular mechanism against hypoxia-induced cell death in PC12 cells. The results of this study showed that fisetin significantly restored the cell viability of PC12 cells under both cobalt chloride (CoCl₂)- and low oxygen-induced hypoxic conditions. Treatment with fisetin successfully reduced the CoCl₂-mediated reactive oxygen species (ROS) production, which was accompanied by an increase in the cell viability of PC12 cells. Furthermore, we found that treatment of PC12 cells with fisetin markedly upregulated hypoxia-inducible factor 1α (HIF-1α), its nuclear accumulation and the hypoxia-response element (HRE)-driven transcriptional activation. The fisetin-mediated cytoprotection during CoCl₂ exposure was significantly attenuated through the administration of HIF-1α siRNA. Moreover, we demonstrated that MAPK/ERK kinase 1/2 (MEK1/2), p38 MAPK and phosphatidylinositol 3-kinase (PI3 K) inhibitors significantly blocked the increase in cell survival that was induced by fisetin treatment under hypoxic conditions. Consistently, increased phosphorylation of ERK, p38 and Akt proteins was observed in PC12 cells treated with fisetin. However, the fisetin-induced HRE-driven transcription was not affected by inhibition of these kinase signaling pathways. Current results reveal for the first time that fisetin promotes cell survival and protects against hypoxia-induced cell death through ROS scavenging and the activation of HIF1α-, MAPK/ERK-, p38 MAPK- and PI3 K/Akt-dependent signaling pathways in PC12 cells.

  19. Hypoxia decreases creatine uptake in cardiomyocytes, while creatine supplementation enhances HIF activation.

    Science.gov (United States)

    Santacruz, Lucia; Arciniegas, Antonio Jose Luis; Darrabie, Marcus; Mantilla, Jose G; Baron, Rebecca M; Bowles, Dawn E; Mishra, Rajashree; Jacobs, Danny O

    2017-08-01

    Creatine (Cr), phosphocreatine (PCr), and creatine kinases (CK) comprise an energy shuttle linking ATP production in mitochondria with cellular consumption sites. Myocytes cannot synthesize Cr: these cells depend on uptake across the cell membrane by a specialized creatine transporter (CrT) to maintain intracellular Cr levels. Hypoxia interferes with energy metabolism, including the activity of the creatine energy shuttle, and therefore affects intracellular ATP and PCr levels. Here, we report that exposing cultured cardiomyocytes to low oxygen levels rapidly diminishes Cr transport by decreasing V max and K m Pharmacological activation of AMP-activated kinase (AMPK) abrogated the reduction in Cr transport caused by hypoxia. Cr supplementation increases ATP and PCr content in cardiomyocytes subjected to hypoxia, while also significantly augmenting the cellular adaptive response to hypoxia mediated by HIF-1 activation. Our results indicate that: (1) hypoxia reduces Cr transport in cardiomyocytes in culture, (2) the cytoprotective effects of Cr supplementation are related to enhanced adaptive physiological responses to hypoxia mediated by HIF-1, and (3) Cr supplementation increases the cellular ATP and PCr content in RNCMs exposed to hypoxia. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  20. Basal HIF-1a expression levels are not predictive for radiosensitivity of human cancer cell lines

    International Nuclear Information System (INIS)

    Schilling, D.; Multhoff, G.; Helmholtz Center Munich, CCG - Innate Immunity in Tumor Biology, Munich; Bayer, C.; Emmerich, K.; Molls, M.; Vaupel, P.; Huber, R.M.

    2012-01-01

    High levels of hypoxia inducible factor (HIF)-1a in tumors are reported to be associated with tumor progression and resistance to therapy. To examine the impact of HIF-1a on radioresistance under normoxia, the sensitivity towards irradiation was measured in human tumor cell lines that differ significantly in their basal HIF-1a levels. HIF-1a levels were quantified in lysates of H1339, EPLC-272H, A549, SAS, XF354, FaDu, BHY, and CX- tumor cell lines by ELISA. Protein levels of HIF-1a, HIF-2a, carbonic anhydrase IX (CA IX), and GAPDH were assessed by Western blot analysis. Knock-down experiments were performed using HIF-1a siRNA. Clonogenic survival after irradiation was determined by the colony forming assay. According to their basal HIF-1a status, the tumor cell lines were divided into low (SAS, XF354, FaDu, A549, CX-), intermediate (EPLC-272H, BHY), and high (H1339) HIF-1a expressors. The functionality of the high basal HIF-1a expression in H1339 cells was proven by reduced CA IX expression after knocking-down HIF-1a. Linear regression analysis revealed no correlation between basal HIF-1a levels and the survival fraction at either 2 or 4 Gy in all tumor cell lines investigated. Our data suggest that basal HIF-1a levels in human tumor cell lines do not predict their radiosensitivity under normoxia. (orig.)