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

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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.

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

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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.

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

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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

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

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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.

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

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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.

HIF1α deficiency reduces inflammation in a mouse model of proximal colon cancer

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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

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

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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.

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

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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.

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

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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.

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

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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

Inhibition of HIF-2.alpha. heterodimerization with HIF1.beta. (ARNT)

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Bruick, Richard K.; Caldwell, Charles G.; Frantz, Doug E.; Gardner, Kevin H.; MacMillan, John B.; Scheuermann, Thomas H.; Tambar, Uttam K.

2017-09-12

Provided is a method of inhibiting heterodimerization of HIF-2.alpha. to HIF1.beta. (ARNT) comprising binding certain small molecules to the HIF-2.alpha. PAS-B domain cavity but not to HIF1.alpha. and inhibiting HIF-2.alpha. heterodimerization to HIF1.beta. (ARNT) but not inhibiting HIF1.alpha. heterodimerization to HIF1.beta. (ARNT). Those certain small molecules are also referenced synonymously as HIF2-HDI and HIF2.alpha. heterodimerization inhibitors and also simply as certain small molecules.

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

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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

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

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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.

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

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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.

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

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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.

Pin1, a new player in the fate of HIF-1α degradation: an hypothetical mechanism inside vascular damage as Alzheimer’s disease risk factor.

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Elena eLonati

2014-01-01

Full Text Available Aetiology of neurodegenerative mechanisms underlying Alzheimer's disease (AD are still under elucidation. The contribution of cerebrovascular deficiencies (such as cerebral ischemia/stroke has been strongly endorsed in recent years. Reduction of blood supply leading to hypoxic condition is known to activate cellular responses mainly controlled by hypoxia-inducible transcription factor-1 (HIF-1. Thus alterations of oxygen responsive HIF-1α subunit in the central nervous system may contribute to the cognitive decline, especially influencing mechanisms associated to APP (amyloid precursor protein amyloidogenic metabolism. Although HIF-1α protein level is known to be regulated by von Hippel-Lindau (VHL ubiquitin-proteasome system, it has been recently suggested that Gsk-3β (glycogen synthase kinase-3β promotes a VHL-independent HIF-1α degradation. Here we provide evidences that in rat primary hippocampal cell cultures, HIF-1α degradation might be mediated by a synergic action of Gsk-3β and Pin1 (peptidyl-prolyl cis/trans isomerase. In post-ischemic conditions, such as those mimicked with oxygen glucose deprivation (OGD, HIF-1α protein level increases remaining unexpectedly high for long time after normal condition restoration jointly with the increase of LDH (lactate dehydrogenase and BACE1 (β-secretase 1 protein expression (70% and 140% respectively. Interestingly the Pin1 activity decreases about 40%-60% and Pin1S16 inhibitory phosphorylation significantly increases, indicating that Pin1 binding to its substrate and enzymatic activity are reduced by treatment. Co-immunoprecipitation experiments demonstrate that HIF-1α/Pin1 in normoxia are associated, and that in presence of specific Pin1 and Gsk-3β inhibitors their interaction is reduced in parallel to an increase of HIF-1α protein level. Thus we suggest that in post-OGD neurons the high level of HIF-1α might be due to Pin1 binding ability and activity reduction which affects HIF-1�

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

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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.

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

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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.

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

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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.

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

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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.

Differential regulation of HIF-1α and HIF-2α in neuroblastoma: Estrogen-related receptor alpha (ERRα) regulates HIF2A transcription and correlates to poor outcome

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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

Differential regulation of HIF-1α and HIF-2α in neuroblastoma: Estrogen-related receptor alpha (ERRα) regulates HIF2A transcription and correlates to poor outcome

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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.

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)

Basal HIF-1a expression levels are not predictive for radiosensitivity of human cancer cell lines

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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.)

Combination of HIF-1α gene transfection and HIF-1-activated bone marrow-derived angiogenic cell infusion improves burn wound healing in aged mice.

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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.

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

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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.

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

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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.

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

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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.

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

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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.

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.

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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

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

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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.

HIF1-alpha overexpression indicates a good prognosis in early stage squamous cell carcinomas of the oral floor

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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.

Effects of HIF-1 and HIF2 on Growth and Metabolism of Clear-Cell Renal Cell Carcinoma 786-0 Xenografts

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Swethajit Biswas

2010-01-01

Full Text Available In cultured clear-cell renal carcinoma (CCRCC 786-0 cells transfected with HIF1 (HIF-1+, HIF-2 (HIF-2+, or empty vector (EV, no significant differences were observed in the growth rates in vitro, but when grown in vivo as xenografts HIF-2 significantly increased, and HIF-1 significantly decreased growth rates, compared to EV tumors. Factors associated with proliferation were increased and factors associated with cell death were decreased in HIF-2+ tumors. Metabolite profiles showed higher glucose and lower lactate and alanine levels in the HIF-2+ tumors whilst immunostaining demonstrated higher pyruvate dehydrogenase and lower pyruvate dehydrogenase kinase 1, compared to control tumors. Taken together, these results suggest that overexpression of HIF-2 in CCRCC 786-0 tumors regulated growth both by maintaining a low level of glycolysis and by allowing more mitochondrial metabolism and tolerance to ROS induced DNA damage. The growth profiles observed may be mediated by adaptive changes to a more oxidative phenotype.

Myeloid HIF-1 is protective in Helicobacter pylori-mediated gastritis.

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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.

HIF1α and HIF2α: sibling rivalry in hypoxic tumour growth and progression.

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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.

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

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

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

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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.

The interplay between HIF-1 and calcium signalling in cancer.

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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.

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....

Hif-1α and Hif-2α synergize to suppress AML development but are dispensable for disease maintenance.

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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.

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

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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.

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

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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.

Increased Levels of VEGF-A and HIF-1α in Turkish Children with Crimean-Congo Hemorrhagic Fever

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Murat Sefikogullari

2017-04-01

Full Text Available Background: Crimean-Congo Hemorrhagic Fever (CCHF is a disease characterized by serious course, including acute viral fever, ecchymosis, thrombocytopenia, liver dysfunction and high rate of mortality. Hypoxia Inducible Factor-1α (HIF-1α and Vascular Endothelial Growth Factor-A (VEGF-A play an important role both in the inflamma­tory process and plasma leakage. The aim of this study was to define HIF-1α and VEGF-A serum levels obtained from CCHF patients and control group and to investigate whether these factors were correlated with the pathogenesis of this disease.Methods: Thirty cases younger than 17 yr confirmed by RT-PCR and/or ELISA for CCHF were included in this study. Thirty age and sex matched healthy peoples were enrolled as controls. Blood samples collected from the pa­tient and control groups. Serum levels of HIF-1α and VEGF-A were measured with ELISA.Results: Levels of HIF-1α and VEGF-A were statistically significantly increased in CCHF patients compared to the control group (P< 0.05.  A significant positive correlation was found between the levels of HIF-1α and VEGF-A in the patient group (P< 0.01. The levels of ALT, AST, CK, aPTT, WBC and Thrombocyte count were significantly higher in the patients than in the control group (P< 0.001. A positive correlation was found among the levels of AST and CK from biochemical parame­ters and VEGF and HIF-1α in the patient group (P< 0.05Conclusion: HIF-1α and VEGF-A might play an important role in CCHF pathogenesis.

Wogonin inhibits tumor angiogenesis via degradation of HIF-1α protein

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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. �

Wogonin inhibits tumor angiogenesis via degradation of HIF-1α protein

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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. �

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

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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

Differential expression of OPN, VEGF-A, and HIF-1α and its clinical significance in hepatocellular carcinoma

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ZHENG Yan

2013-01-01

Full Text Available ObjectiveTo investigate the expression patterns of osteopontin (OPN, vascular endothelial growth factor-A (VEGF-A, and hypoxia-inducible factor-1α(HIF-1α in primary hepatocellular carcinoma (HCC and determine the clinical significance of this differential expression profile. MethodsImmunohistochemical staining of OPN, VEGF-A, and HIF-1α was carried out on primary HCC tissues from 90 patients, HCC-adjacent cirrhosis tissues from 20 of those patients, and normal liver tissues from 15 healthy controls. Correlations between expression levels and HCC clinicopathological characteristics were assessed by Spearman's correlation coefficient. ResultsThe majority of HCC tissues showed positive immunostaining for OPN (69/90, 76.67%, VEGF-A (64/90, 71.11%, and HIF-1α (66/90, 73.33%. OPN- and VEGF-A-positivity were significantly higher than the results from the cirrhosis tissues and normal tissues. HIF-1α-positivity was similar between the HCC and cirrhosis tissues, but both were significantly different from the normal tissues. The differential expressions of OPN, VEGF-A, and HIF-1α were significantly correlated with tumor thrombus, capsular integrity, tumor differentiation and stage, and metastasis (P＜0.05. ConclusionHCC tissues overexpress OPN, VEGF-A, and HIF-1α and this differential profile may be related to HCC progression. Future investigations of this triad of factors may provide novel insights into the biological characteristics of HCC and reveal important targets of molecular therapy.

HIF-1α effects on angiogenic potential in human small cell lung carcinoma

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Xia Wanli

2011-08-01

Full Text Available Abstract Background Hypoxia-inducible factor-1 alpha (HIF-1α maybe an important regulatory factor for angiogenesis of small cell lung cancer (SCLC. Our study aimed to investigate the effect of HIF-1α on angiogenic potential of SCLC including two points: One is the effect of HIF-1α on the angiogenesis of SCLC in vivo. The other is the regulation of angiogenic genes by HIF-1α in vitro and in vivo. Methods In vivo we used an alternative method to study the effect of HIF-1a on angiogenic potential of SCLC by buliding NCI-H446 cell transplantation tumor on the chick embryo chorioallantoic membrane (CAM surface. In vitro we used microarray to screen out the angiogenic genes regulated by HIF-1a and tested their expression level in CAM transplantation tumor by RT-PCR and Western-blot analysis. Results In vivo angiogenic response surrounding the SCLC transplantation tumors in chick embryo chorioallantoic membrane (CAM was promoted after exogenous HIF-1α transduction (p In vitro the changes of angiogenic genes expression induced by HIF-1α in NCI-H446 cells were analyzed by cDNA microarray experiments. HIF-1α upregulated the expression of angiogenic genes VEGF-A, TNFAIP6, PDGFC, FN1, MMP28, MMP14 to 6.76-, 6.69-, 2.26-, 2.31-, 4.39-, 2.97- fold respectively and glycolytic genes GLUT1, GLUT2 to2.98-, 3.74- fold respectively. In addition, the expression of these angiogenic factors were also upregulated by HIF-1α in the transplantion tumors in CAM as RT-PCR and Western-blot analysis indicated. Conclusions These results indicated that HIF-1α may enhance the angiogenic potential of SCLC by regulating some angiogenic genes such as VEGF-A, MMP28 etc. Therefore, HIF-1α may be a potential target for the gene targeted therapy of SCLC.

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

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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.

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

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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.

Trichostatin A resistance is facilitated by HIF-1α acetylation in HeLa human cervical cancer cells under normoxic conditions

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Lee, Jae-Wook; Yang, Dong Hee; Park, Sojin; Han, Hae-Kyoung; Park, Jong-Wan; Kim, Bo Yeon; Um, Sung Hee; Moon, Eun-Yi

2018-01-01

Trichostatin A (TSA) is an anticancer drug that inhibits histone deacetylases (HDACs). Hypoxia-inducible factor 1 (HIF-1) participates in tumor angiogenesis by upregulating target genes, such as vascular endothelial growth factor (VEGF). In the present study, we investigated whether TSA treatment increases HIF-1α stabilization via acetylation under normoxic conditions, which would lead to VEGF upregulation and resistance to anticancer drugs. TSA enhanced total HIF-1α and VEGF-HRE reporter activity under normoxic conditions. When cells were transfected with GFP-HIF-1α, treatment with TSA increased the number of green fluorescence protein (GFP)-positive cells. TSA also enhanced the nuclear translocation of HIF-1α protein, as assessed by immunoblotting and as evidenced by increased nuclear localization of GFP-HIF-1α. An increase in the interaction between HIF-1α and the VEGF promoter, which was assessed by a chromatin immunoprecipitation (ChIP) assay, led to activation of the VEGF promoter. TSA acetylated HIF-1α at lysine (K) 674, which led to an increase in TSA-induced VEGF-HRE reporter activity. In addition, TSA-mediated cell death was reduced by the overexpression of HIF-1α but it was rescued by transfection with a HIF-1α mutant (K674R). These data demonstrate that HIF-1α may be stabilized and translocated into the nucleus for the activation of VEGF promoter by TSA-mediated acetylation at K674 under normoxic conditions. These findings suggest that HIF-1α acetylation may lead to resistance to anticancer therapeutics, such as HDAC inhibitors, including TSA. PMID:29416751

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

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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.

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

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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.

Silencing HIF-1α reduces the adhesion and secretion functions of acute leukemia hBMSCs

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Zeng, Dong-Feng; Liu, Ting; Chang, Cheng; Zhang, Xi; Liang, Xue; Chen, Xing-Hua; Kong, Pei-Yan

2012-01-01

Hypoxia inducible factor-1α (HIF-1α) is an important transcription factor, which plays a critical role in the formation of solid tumor and its microenvironment. The objective of the present study was to evaluate the expression and function of HIF-1α in human leukemia bone marrow stromal cells (BMSCs) and to identify the downstream targets of HIF-1α. HIF-1α expression was detected at both the RNA and protein levels using real-time PCR and immunohistochemistry, respectively. Vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1α (SDF-1α) were detected in stromal cells by enzyme-linked immunosorbent assay. HIF-1α was blocked by constructing the lentiviral RNAi vector system and infecting the BMSCs. The Jurkat cell/BMSC co-cultured system was constructed by putting the two cells into the same suitable cultured media and conditions. Cell adhesion and secretion functions of stromal cells were evaluated after transfection with the lentiviral RNAi vector of HIF-1α. Increased HIF-1α mRNA and protein was detected in the nucleus of the acute myeloblastic and acute lymphoblastic leukemia compared with normal BMSCs. The lentiviral RANi vector for HIF-1α was successfully constructed and was applied to block the expression of HIF-1α. When HIF-1α of BMSCs was blocked, the expression of VEGF and SDF-1α secreted by stromal cells was decreased. When HIF-1α was blocked, the co-cultured Jurkat cell's adhesion and migration functions were also decreased. Taken together, these results suggest that HIF-1α acts as an important transcription factor and can significantly affect the secretion and adhesion functions of leukemia BMSCs

Silencing HIF-1α reduces the adhesion and secretion functions of acute leukemia hBMSCs

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Zeng, Dong-Feng [Department of Hematology, XinQiao Hospital, Third Military Medical University, ChongQing (China); Liu, Ting [Department of Ophthalmology, DaPing Hospital, Third Military Medical University, ChongQing (China); Chang, Cheng; Zhang, Xi; Liang, Xue; Chen, Xing-Hua; Kong, Pei-Yan [Department of Hematology, XinQiao Hospital, Third Military Medical University, ChongQing (China)

2012-06-29

Hypoxia inducible factor-1α (HIF-1α) is an important transcription factor, which plays a critical role in the formation of solid tumor and its microenvironment. The objective of the present study was to evaluate the expression and function of HIF-1α in human leukemia bone marrow stromal cells (BMSCs) and to identify the downstream targets of HIF-1α. HIF-1α expression was detected at both the RNA and protein levels using real-time PCR and immunohistochemistry, respectively. Vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1α (SDF-1α) were detected in stromal cells by enzyme-linked immunosorbent assay. HIF-1α was blocked by constructing the lentiviral RNAi vector system and infecting the BMSCs. The Jurkat cell/BMSC co-cultured system was constructed by putting the two cells into the same suitable cultured media and conditions. Cell adhesion and secretion functions of stromal cells were evaluated after transfection with the lentiviral RNAi vector of HIF-1α. Increased HIF-1α mRNA and protein was detected in the nucleus of the acute myeloblastic and acute lymphoblastic leukemia compared with normal BMSCs. The lentiviral RANi vector for HIF-1α was successfully constructed and was applied to block the expression of HIF-1α. When HIF-1α of BMSCs was blocked, the expression of VEGF and SDF-1α secreted by stromal cells was decreased. When HIF-1α was blocked, the co-cultured Jurkat cell's adhesion and migration functions were also decreased. Taken together, these results suggest that HIF-1α acts as an important transcription factor and can significantly affect the secretion and adhesion functions of leukemia BMSCs.

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

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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.

Necrosis related HIF-1α expression predicts prognosis in patients with endometrioid endometrial carcinoma

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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

Upregulation of the Chemokine Receptor CCR7 expression by HIF-1αand HIF-2α in non-small cell lung cancer

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Yang LI

2008-10-01

Full Text Available Background and objective CCR7 is closely related with the lymph node metastasis of non-small cell lung cancer. The objective of this work is to investigate the expressions of chemokine receptor CCR7, hypoxiainducible factor 1α (HIF-1α and hypoxia inducible factor 2α (HIF-2α protein in non small cell lung cancer and the relationships of their expression, and to study the mechanism of CCR7 upregulation in NSCLC. Methods T he levels of expressions of CCR7, HIF-1α and HIF-2α protein were detected in 94 specimens of human primary non small cell lung cancer by immunohistochemical S-P method. Human lung adenocarcinoma cell line A549 cells were transfected by lipofection with HIF-1α siRNA、HIF-2α siRNA, the change of CCR7 was observed by RT-PCR and immunofluorescence staining. Correlations between the expression of CCR7 and HIF-1α, HIF-2α were respectively analyzed. Results Immunohistochemistry showed that CCR7 was distributed in cytoplasm and/or membrane of tumor cells, HIF-1α, HIF-2α was distributed in nucleus and/or cytoplasm of tumor cells. The levels of expressions of CCR7, HIF-1α and HIF-2α protein were found to be 75.53% (71/94, 54.25% (51/ 94 and 70.21% (66/94 in non small celllung cancer, respectively. the levels of expression of CCR7 protein were closely related to the clinical stages (P 0.05. Furthermore, A significant correlation were found among CCR7, Hif-1α and HIF-2α (r =0.272, P <0.01 (r=0.225, P <0.05. In addition, the expression of CCR7 mRNA and protein levels were decreased in the transfected specificHIF-1α, HIF-2αsiRNA group (P <0.05. Conclusion CCR7 expression is significantly associated with non small cell lung cancer invasion and metastasis. The upregulation of CCR7 is regulated by HIF-1α and HIF-2α in non small cell lung cancer.

Regulation of HIF prolyl hydroxylases by hypoxia-inducible factors.

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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.

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.

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

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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

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

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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.

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

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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.

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...

HIF-1α pathway: role, regulation and intervention for cancer therapy

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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.

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

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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.

The epigenetic regulation of HIF-1α by SIRT1 in MPP{sup +} treated SH-SY5Y cells

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Dong, Su-Yan; Guo, Yan-Jie; Feng, Ya; Cui, Xin-Xin [Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080 (China); Kuo, Sheng-Han [Department of Neurology, College of Physicians and Surgeons, Columbia University, New York (United States); Liu, Te, E-mail: liute1979@126.com [Shanghai Geriatric Institute of Chinese Medicine, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200031 (China); Wu, Yun-Cheng, E-mail: yunchw@medmail.com.cn [Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080 (China)

2016-02-05

Both silent information regulator 1 (SIRT1) and hypoxia inducible factor 1 (HIF-1) have been found to play important roles in the pathophysiology of Parkinson's disease (PD). However, their mechanisms and their relationship still require further study. In the present study, we focused on the change and relationship of SIRT1 and HIF-1α in PD. PD cell models were established by using methyl-4-phenylpyridinium (MPP{sup +}), which induced inhibition of cell proliferation, cell cycle arrest and apoptosis. We found that the expression of HIF-1α and its target genes VEGFA and LDHA increased and that SIRT1 expression was inhibited in MPP{sup +} treated cells. With further analysis, we found that the acetylation of H3K14 combined with the HIF-1α promoter was dramatically increased in cells treated with MPP{sup +}, which resulted in the transcriptional activation of HIF-1α. Moreover, the acetylation of H3K14 and the expression of HIF-1α increased when SIRT1 was knocked down, suggesting that SIRT1 was involved in the epigenetic regulation of HIF-1α. At last, phenformin, another mitochondrial complex1 inhibitor, was used to testify that the increased HIF-1a was not due to off target effects of MPP{sup +}. Therefore, our results support a link between PD and SIRT1/HIF-1α signaling, which may serve as a clue for understanding PD.

HIF-1α inhibition reverses multidrug resistance in colon cancer cells via downregulation of MDR1/P-glycoprotein.

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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.

Lung macrophages contribute to house dust mite driven airway remodeling via HIF-1α.

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Adam J Byrne

Full Text Available HIF-1α is a transcription factor that is activated during hypoxia and inflammation and is a key regulator of angiogenesis in vivo. During the development of asthma, peribronchial angiogenesis is induced in response to aeroallergens and is thought to be an important feature of sustained chronic allergic inflammation. Recently, elevated HIF-1α levels have been demonstrated in both the lung tissue and bronchoalveolar lavage of allergic patients, respectively. Therefore, we investigated the role of HIF-1α on the development of angiogenesis and inflammation following acute and chronic allergen exposure. Our data shows that intranasal exposure to house dust mite (HDM increases the expression of HIF-1α in the lung, whilst reducing the expression of the HIF-1α negative regulators, PHD1 and PHD3. Blockade of HIF-1α in vivo, significantly decreased allergic inflammation and eosinophilia induced by allergen, due to a reduction in the levels of IL-5 and Eotaxin-2. Importantly, HIF-1α blockade significantly decreased levels of VEGF-A and CXCL1 in the lungs, which in turn led to a profound decrease in the recruitment of endothelial progenitor cells and a reduction of peribronchial angiogenesis. Furthermore, HDM or IL-4 treatment of primary lung macrophages resulted in significant production of both VEGF-A and CXCL1; inhibition of HIF-1α activity abrogated the production of these factors via an up-regulation of PHD1 and PHD3. These findings suggest that novel strategies to reduce the expression and activation of HIF-1α in lung macrophages may be used to attenuate allergen-induced airway inflammation and angiogenesis through the modulation of VEGF-A and CXCL1 expression.This study provides new insights into the role of HIF-1α in the development of peribronchial angiogenesis and inflammation in a murine model of allergic airway disease. These findings indicate that strategies to reduce activation of macrophage derived HIF-1α may be used as a target to

HIF-2alpha-dependent PAI-1 induction contributes to angiogenesis in hepatocellular carcinoma

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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.

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

Aminoflavone, a ligand of the Aryl Hydrocarbon Receptor (AhR), inhibits HIF-1α expression in an AhR-independent fashion

Science.gov (United States)

Terzuoli, Erika; Puppo, Maura; Rapisarda, Annamaria; Uranchimeg, Badarch; Cao, Liang; Burger, Angelika M.; Ziche, Marina; Melillo, Giovanni

2010-01-01

Aminoflavone (AF), the active component of a novel anticancer agent (AFP464) in phase I clinical trials, is a ligand of the aryl hydrocarbon receptor (AhR). AhR dimerizes with HIF-1β/ARNT, which is shared with HIF-1α, a transcription factor critical for the response of cells to oxygen deprivation. To address whether pharmacological activation of the AhR pathway might be a potential mechanism for inhibition of HIF-1, we tested the effects of AF on HIF-1 expression. AF inhibited HIF-1α transcriptional activity and protein accumulation in MCF-7 cells. However, inhibition of HIF-1α by AF was independent from a functional AhR pathway. Indeed, AF inhibited HIF-1α expression in AhR100 cells, in which the AhR pathway is functionally impaired, yet did not induce cytotoxicity, providing evidence that these effects are mediated by distinct signaling pathways. Moreover, AF was inactive in MDA-MB-231 cells, yet inhibited HIF-1α in MDA-MB-231 cells transfected with the SULT1A1 gene. AF inhibited HIF-1α mRNA expression by approximately 50%. Notably, actinomycin-D completely abrogated the ability of AF to down-regulate HIF-1α mRNA, indicating that active transcription was required for the inhibition of HIF-1α expression. Finally, AF inhibited HIF-1α protein accumulation and the expression of HIF-1-target genes in MCF-7 xenografts. These results demonstrate that AF inhibits HIF-1α in an AhR-independent fashion and they unveil additional activities of AF that may be relevant for its further clinical development. PMID:20736373

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

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.

HIF-1α and GLUT-1 Expression in Atypical Endometrial Hyperplasia, Type I and II Endometrial Carcinoma: A Potential Role in Pathogenesis

Science.gov (United States)

Abdou, Asmaa Gaber; Wahed, Moshira Mohammed Abdel; Kassem, Hend Abdou

2016-01-01

Introduction Hypoxia-Inducible Factor 1α (HIF-1α) is one of the major adaptive responses to hypoxia, regulating the activity of glucose transporter -1 (GLUT-1), responsible for glucose uptake. Aim To evaluate the immunohistochemical expression of both HIF-1α and GLUT-1 in type I and II endometrial carcinoma and their correlation with the available clinicopathologic variables in each type. Materials and Methods A retrospective study was conducted on archival blocks diagnosed from pathology department between April 2010 and August 2014 included 9 cases of atypical hyperplasia and 67 cases of endometrial carcinoma. Evaluation of both HIF-1α and GLUT-1 expression using standard immunohistochemical techniques performed on cut sections from selected paraffin embedded blocks. Statistical Analysis Descriptive analysis of the variables and statistical significances were calculated by non-parametric chi-square test using the Statistical Package for the Social Sciences version 12.0 (SPSS). Results HIF-1α was expressed in epithelial (88.9%, 52.2%, 61.2% and 50%) and stromal (33.3%, 74.6%. 71.4% and 83.3%) components of hyperplasia, total cases of EC, type I and II EC, respectively. GLUT-1 was expressed in the epithelial component of 88.9%, 98.5%, 98% and 100% of hyperplasia, total EC cases, type I and II EC, respectively. The necrosis related pattern of epithelial HIF-1α expression was in favour of type II (p=0.018) and grade III (p=0.038). HIF-1α H-score was associated with high apoptosis in both type I and total cases of EC (p=0.04). GLUT-1 H-score was negatively correlated with apoptotic count (p=0.04) and associated with high grade (p=0.003) and advanced stage in total EC (p=0.004). GLUT-1 H-score was correlated with the pattern of HIF-1α staining in all cases of EC (p= 0.04). Conclusion The role of HIF-1α in epithelial cells may differ from that of stromal cells in EC; however they augment the expression of each other supporting the crosstalk between them. The

Downregulation of HIF-1a sensitizes U251 glioma cells to the temozolomide (TMZ) treatment

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Tang, Jun-Hai [Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, Chongqing 400037 (China); Ma, Zhi-Xiong [National Institute of Biological Sciences, Beijing 102206 (China); Huang, Guo-Hao; Xu, Qing-Fu; Xiang, Yan [Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, Chongqing 400037 (China); Li, Ningning; Sidlauskas, Kastytis [Division of Neuropathology and Department of Neurodegenerative Disease, Institute of Neurology, University College London, London WC1N 3BG (United Kingdom); Zhang, Eric Erquan [National Institute of Biological Sciences, Beijing 102206 (China); Lv, Sheng-Qing, E-mail: lvsq0518@hotmail.com [Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, Chongqing 400037 (China)

2016-05-01

Purpose: The aim of this study was to investigate the effect of downregulation of HIF-1α gene on human U251 glioma cells and examine the consequent changes of TMZ induced effects and explore the molecular mechanisms. Methods: U251 cell line stably expressing HIF-1α shRNA was acquired via lentiviral vector transfection. The mRNA and protein expression alterations of genes involved in our study were determined respectively by qRT-PCR and Western blot. Cell proliferation was measured by MTT assay and colony formation assay, cell invasion/migration capacity was determined by transwell invasion assay/wound healing assay, and cell apoptosis was detected by flow cytometry. Results: We successfully established a U251 cell line with highly efficient HIF-1α knockdown. HIF-1a downregulation sensitized U251 cells to TMZ treatment and enhanced the proliferation-inhibiting, invasion/migration-suppressing, apoptosis-inducing and differentiation-promoting effects exerted by TMZ. The related molecular mechanisms demonstrated that expression of O{sup 6}-methylguanine DNA methyltransferase gene (MGMT) and genes of Notch1 pathway were significantly upregulated by TMZ treatment. However, this upregulation was abrogated by HIF-1α knockdown. We further confirmed important regulatory roles of HIF-1α in the expression of MGMT and activation of Notch1 pathways. Conclusion: HIF-1α downregulation sensitizes U251 glioma cells to the temozolomide treatment via inhibiting MGMT expression and Notch1 pathway activation. - Highlights: • TMZ caused more significant proliferation inhibition and apoptosis in U251 cells after downregulating HIF-1α. • Under TMZ treatment, HIF-1 downregulated U251 cells exhibited weaker mobility and more differentiated state. • TMZ caused MGMT over-expression and Notch1 pathway activation, which could be abrogated by HIF-1α downregulation.

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

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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.

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.

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.

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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.

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

Hispidulin inhibits proliferation and enhances chemosensitivity of gallbladder cancer cells by targeting HIF-1α

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Gao, Hui; Xie, Jing [Medical College, Qingdao University, Qingdao, Shandong 266071 (China); Peng, Jianjun, E-mail: jianjunpeng@126.com [College of Life Sciences, Chongqing Normal University, Chongqing 401331 (China); Han, Yantao, E-mail: hanyt19@126.com [Medical College, Qingdao University, Qingdao, Shandong 266071 (China); Jiang, Qixiao; Han, Mei; Wang, Chunbo [Medical College, Qingdao University, Qingdao, Shandong 266071 (China)

2015-03-15

Gallbladder cancer (GBC) is an aggressive malignancy of the bile duct, which is associated with a low (5-year) survival and poor prognosis. The transcription factor HIF-1α is implicated in the angiogenesis, cell survival, epithelial mesenchymal transition (EMT) and invasiveness of GBC. In this study, we have investigated the role of HIF-1α in the pathobilogy of GBC and effect of hispidulin on the molecular events controlled by this transcription factor. We observed that hispidulin caused induction of apoptosis, blockade of growth and cell cycle progression in GBC cells. Our results have demonstrated for the first time that hispidulin-exerted anti-tumor effect involved the suppression of HIF-1α signaling. Hispidulin was found to repress the expression of HIF-1α protein dose-dependently without affecting the HIF-1α mRNA expression. In addition, the inhibition of HIF-1α protein synthesis was revealed to be mediated through the activation of AMPK signaling. Hispidulin also sensitized the tumor cells to Gemcitabine and 5-Fluoroucil by down-regulating HIF-1α/P-gp signaling. Given the low cost and exceedingly safe profile, hispidulin appears to be a promising and novel chemosensitizer for GBC treatment. - Highlights: • Hispidulin inhibits proliferation of gallbladder cancer cells by targeting HIF-1α. • Hispidulin regulates HIF-1α via activating AMPK signaling. • Hispidulin sensitized the GBC cells to chemotherapeutics by down-regulating P-gp.

Intermittent induction of HIF-1α produces lasting effects on malignant progression independent of its continued expression.

Directory of Open Access Journals (Sweden)

Hyunsung Choi

Full Text Available Dysregulation of hypoxia-inducible transcription factors HIF-1α and HIF-2α correlates with poor prognosis in human cancers; yet, divergent and sometimes opposing activities of these factors in cancer biology have been observed. Adding to this complexity is that HIF-1α apparently possesses tumor-suppressing activities, as indicated by the loss-of-function mutations or even homozygous deletion of HIF1A in certain human cancers. As a step towards understanding this complexity, we employed 8-week intermittent induction of a stable HIF-1α variant, HIF1α(PP, in various cancer cell lines and examined the effects on malignant progression in xenografts of immunocompromised mice in comparison to those of HIF2α(PP. Although 8-week treatment led to eventual loss of HIF1α(PP expression, treated osteosarcoma U-2 OS cells acquired tumorigenicity in the subcutaneous tissue. Furthermore, the prior treatment resulted in widespread invasion of malignant glioma U-87 MG cells in the mouse brain and sustained growth of U-118 MG glioma cells. The lasting effects of HIF-1α on malignant progression are specific because neither HIF2α(PP nor β-galactosidase yielded similar effects. By contrast, transient expression of HIF1α(PP in U-87 MG cells or constitutive expression of HIF1α(PP but not HIF2α(PP in a patient-derived glioma sphere culture inhibited tumor growth and spread. Our results indicate that intermittent induction of HIF-1α produces lasting effects on malignant progression even at its own expense.

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-1–HIF-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

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-1–HIF-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

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.

Prognostic impact of HIF-1{alpha} expression in patients with definitive radiotherapy for cervical cancer

Energy Technology Data Exchange (ETDEWEB)

Dellas, K.; Bache, M.; Kappler, M.; Haensgen, G. [Halle-Wittenberg Univ., Halle (Germany). Dept. of Radiotherapy; Pigorsch, S.U. [Technische Univ. Muenchen (Germany). Dept. of Radiotherapy and Radiation Oncology; Taubert, H.; Holzhausen, H.J. [Halle-Wittenberg Univ., Halle (Germany). Inst. of Pathology; Holzapfel, D.; Zorn, E. [Halle-Wittenberg Univ., Halle (Germany). Dept. of Radiotherapy; Halle-Wittenberg Univ., Halle (Germany). Inst. of Pathology

2008-03-15

Purpose: To investigate the relationship between the hypoxia-inducible factor-(HIF-)1{alpha} expression in tumor tissue, tumor oxygenation and hemoglobin levels in patients with advanced cervical cancers prior to radiotherapy and the effect on clinical outcome. Patients and Methods: The investigation included 44 patients who underwent definitive radiotherapy for advanced cervical cancers between May 1995 and March 1999. Tumor biopsies were taken prior to treatment, and HIF-1{alpha} expression was determined by immunohistochemistry. In the same tumor area, tumor tissue oxygenation (pO{sub 2}) was measured using the Eppendorf device. Results: The 5-year cancer-specific survival of all patients was 60%. Twelve of 44 tumor specimens were HIF-1{alpha}-negative with a significantly better 5-year survival (92 {+-} 8%) versus 32 patients who were HIF-1{alpha}-positive (45 {+-} 10%; p < 0.02). There was no correlation between HIF-1{alpha} expression and tumor oxygenation (p = 0.57 both for pO{sub 2} median and hypoxic fraction < 5 mmHg vs. HIF-1{alpha} expression). However, patients with hemoglobin levels < 11 g/dl showed elevated HIF-1{alpha} expression compared to patients with hemoglobin levels > 12.5 g/dl (p = 0.04). Furthermore, HIF-1{alpha} correlated with vascular endothelial growth factor expression (p = 0.002). In a multivariate Cox regression model, HIF-1{alpha} expression (relative risk [RR] = 7.5; p = 0.05) revealed an increased risk of tumor-related death. Conclusion: The study indicates, that endogenous tumor markers such as HIF-1{alpha} may serve as prognostic markers of clinical outcome concerning cervical cancer after primary radiotherapy. (orig.)

Iron overload promotes erythroid apoptosis through regulating HIF-1a/ROS signaling pathway in patients with myelodysplastic syndrome.

Science.gov (United States)

Zheng, Qing-Qing; Zhao, You-Shan; Guo, Juan; Zhao, Si-da; Song, Lu-Xi; Fei, Cheng-Ming; Zhang, Zheng; Li, Xiao; Chang, Chun-Kang

2017-07-01

Erythroid apoptosis increases significantly in myelodysplastic syndrome (MDS) patients with iron overload, but the underlying mechanism is not fully clear. In this study, we aim to explore the effect of HIF-1a/ROS on erythroid apoptosis in MDS patients with iron overload. We found that iron overload injured cellular functions through up-regulating ROS levels in MDS/AML cells, including inhibited cell viability, increased cell apoptosis and blocked cell cycle at G0/G1 phase. Interestingly, overexpression of hypoxia inducible factor-1a (HIF-1a), which was under-expressed in iron overload models, reduced ROS levels and attenuated cell damage caused by iron overload in MDS/AML cells. And gene knockdown of HIF-1a got the similar results as iron overload in MDS/AML cells. Furthermore, iron overload caused high erythroid apoptosis was closely related with ROS in MDS patients. Importantly, the HIF-1a protein levels of erythrocytes elevated obviously after incubation with desferrioxamine (DFO) from MDS patients with iron overload, accompanied by ROS levels inhibited and erythroid apoptosis reduced. Taken together, our findings determine that the HIF-1a/ROS signaling pathway plays a key role in promoting erythroid apoptosis in MDS patients with iron overload. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

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.

Increased expression of HIF-1α, VEGF-A and its receptors, MMP-2, TIMP-1, and ADAMTS-1 at the venous stenosis of arteriovenous fistula in a mouse model with renal insufficiency

Science.gov (United States)

Misra, Sanjay; Shergill, Uday; Yang, Binxia; Janardhanan, Rajiv; Misra, Khamal D.

2010-01-01

Purpose A mouse model of renal insufficiency with arteriovenous fistula (AVF) and venous stenosis was created. We tested the hypothesis that there is increased gene expression of hypoxia inducible factor-1 alpha (HIF-1α), vascular endothelial growth factor- A (VEGF-A) and its receptors (VEGFR-1, -2), matrix metalloproteinase-2 (MMP-2), -9 (MMP-9), tissue inhibitor of metalloproteinase-1, -2 (TIMP-1, -2), and a disintegrin and metalloproteinase thrombospondin-1 (ADAMTS-1) at the venous stenosis. Materials and methods Nineteen male C57BL/6 mice underwent a left nephrectomy and a surgical occlusion of the right upper pole to induce renal insufficiency and characterized in eight mice. Twenty eight days later, an AVF (n=11) was created from the right carotid artery to ipsilateral jugular vein and the mice were sacrificed at day 7 (n=4) and day 14 (n=4). The outflow and control veins were removed for gene expression. Three mice were sacrificed at day 28 for histologic analysis. Results The mean serum blood urea nitrogen remained significantly elevated for 8 weeks when compared to baseline (P<0.05). By day 7, there was a significant increase in the expression of HIF-1α, VEGF-A, VEGFR-1, VEGFR-2, MMP-2, TIMP-1, and ADAMTS-1 at the outflow vein with HIF-1α and TIMP-1 being significantly elevated at day 14 (P<0.05). By day 28, the venous stenosis was characterized by a thickened vein wall and neointima. Conclusions A mouse model of renal insufficiency with AVF was developed which had increased expression of HIF-1α, VEGF-A, VEGFR-1, VEGFR-2, MMP-2, TIMP-1, and ADAMTS-1 at the outflow vein with venous stenosis by day 28. PMID:20598569

Increased expression of HIF-1alpha, VEGF-A and its receptors, MMP-2, TIMP-1, and ADAMTS-1 at the venous stenosis of arteriovenous fistula in a mouse model with renal insufficiency.

Science.gov (United States)

Misra, Sanjay; Shergill, Uday; Yang, Binxia; Janardhanan, Rajiv; Misra, Khamal D

2010-08-01

A mouse model of renal insufficiency with arteriovenous fistula (AVF) and venous stenosis was created. The authors tested the hypothesis that there is increased gene expression of hypoxia-inducible factor-1 alpha (HIF-1alpha); vascular endothelial growth factor-A (VEGF-A) and its receptors (VEGFR-1, -2); matrix metalloproteinase-2 (MMP-2), -9 (MMP-9); tissue inhibitor of metalloproteinase-1, -2 (TIMP-1, -2); and a disintegrin and metalloproteinase thrombospondin-1 (ADAMTS-1) at the venous stenosis. Nineteen male C57BL/6 mice underwent a left nephrectomy and a surgical occlusion of the right upper pole to induce renal function characterized in eight animals. Twenty eight days later, an AVF (n = 11) was created from the right carotid artery to ipsilateral jugular vein, and the mice were killed at day 7 (n = 4) and day 14 (n = 4). The outflow and control veins were removed for gene expression. Three mice were killed at day 28 for histologic analysis. The mean serum blood urea nitrogen level remained significantly elevated for 8 weeks when compared with baseline (P < .05). By day seven, there was a significant increase in the expression of HIF-1alpha, VEGF-A, VEGFR-1, VEGFR-2, MMP-2, TIMP-1, and ADAMTS-1 at the outflow vein, with HIF-1alpha and TIMP-1 levels significantly elevated at day 14 (P < .05). By day 28, the venous stenosis was characterized by a thickened vein wall and neointima. A mouse model of renal insufficiency with AVF was developed that had increased expression of HIF-1alpha, VEGF-A, VEGFR-1, VEGFR-2, MMP-2, TIMP-1, and ADAMTS-1 at the outflow vein with venous stenosis by day 28. Copyright (c) 2010 SIR. Published by Elsevier Inc. All rights reserved.

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.

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....

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.

SDF-1 alpha expression during wound healing in the aged is HIF dependent.

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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.

KAI1 suppresses HIF-1α and VEGF expression by blocking CDCP1-enhanced Src activation in prostate cancer

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Park Jung-Jin

2012-03-01

Full Text Available Abstract Background KAI1 was initially identified as a metastasis-suppressor gene in prostate cancer. It is a member of the tetraspan transmembrane superfamily (TM4SF of membrane glycoproteins. As part of a tetraspanin-enriched microdomain (TEM, KAI1 inhibits tumor metastasis by negative regulation of Src. However, the underlying regulatory mechanism has not yet been fully elucidated. CUB-domain-containing protein 1 (CDCP1, which was previously known as tetraspanin-interacting protein in TEM, promoted metastasis via enhancement of Src activity. To better understand how KAI1 is involved in the negative regulation of Src, we here examined the function of KAI1 in CDCP1-mediated Src kinase activation and the consequences of this process, focusing on HIF-1 α and VEGF expression. Methods We used the human prostate cancer cell line PC3 which was devoid of KAI1 expression. Vector-transfected cells (PC3-GFP clone #8 and KAI1-expressing PC3 clones (PC3-KAI1 clone #5 and #6 were picked after stable transfection with KAI1 cDNA and selection in 800 μg/ml G418. Protein levels were assessed by immunoblotting and VEGF reporter gene activity was measured by assaying luciferase activitiy. We followed tumor growth in vivo and immunohistochemistry was performed for detection of HIF-1, CDCP1, and VHL protein level. Results We demonstrated that Hypoxia-inducible factor 1α (HIF-1α and VEGF expression were significantly inhibited by restoration of KAI1 in PC3 cells. In response to KAI1 expression, CDCP1-enhanced Src activation was down-regulated and the level of von Hippel-Lindau (VHL protein was significantly increased. In an in vivo xenograft model, KAI1 inhibited the expression of CDCP1 and HIF-1α. Conclusions These novel observations may indicate that KAI1 exerts profound metastasis-suppressor activity in the tumor malignancy process via inhibition of CDCP1-mediated Src activation, followed by VHL-induced HIF-1α degradation and, ultimately, decreased VEGF

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

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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.

Expression and clinical significance of the HIF-1a/ET-2 signaling pathway during the development and treatment of polycystic ovary syndrome.

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Wang, Fan; Zhang, Zhenghong; Wang, Zhaokai; Xiao, Kaizhuan; Wang, Qing; Su, Jingqian; Wang, Zhengchao

2015-04-01

Polycystic ovary syndrome (PCOS) is a major health problem in reproductive-aged women worldwide, but the precise pathogenesis of PCOS remains unclear. Our previous study revealed that hypoxia-inducible factor (HIF)-1a mediated endothelin (ET)-2 signaling plays an important role in ovulation in rats. Therefore, the present study used a PCOS rat model to test the hypotheses that HIF-1a signaling is expressed and inhibited in ovaries during PCOS formation and that the HIF-1a/ET-2 signaling pathway is a target of dimethyldiguanide (DMBG) in the clinical treatment of PCOS. First, the development of a PCOS model and the effect of DMBG treatment were examined through ovarian histology and serum hormone levels, which were consistent with previous reports. Second, HIF-1a and ET-2 expression were detected by immunohistochemistry and western blot. The results showed decreased HIF-1a/ET-2 expression in the ovaries of PCOS rats, whereas DMBG treatment reversed the protein decreases and improved the PCOS symptoms. Third, to understand the molecular mechanism, HIF-1a/ET-2 mRNA expression was also examined. Interestingly, HIF-1a mRNA increased in the ovaries of PCOS rats, while ET-2 mRNA decreased, indicating that HIF-1a protein degradation may be involved in POCS development and treatment. Finally, HIF prolyl hydroxylase (PHD) activity was examined to further clarify the contribution of HIF-1a signaling to the development and treatment of PCOS. The results suggested that the inhibition of HIF-1a/ET-2 signaling may be caused by increased PHD activity in PCOS. DMBG-treated PCOS may further activate HIF-1a signaling at least partly through inhibiting PHD activity. Taken together, these results indicate that HIF-1a signaling is inhibited in a PCOS rat model through increasing PHD activity. DMBG treatment improved PCOS by rescuing this pathway, suggesting that HIF-1a signaling plays an important role in the development and treatment of PCOS. This HIF-1a-mediated ET-2 signaling pathway

SIRT3 opposes reprogramming of cancer cell metabolism through HIF1α destabilization

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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

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

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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.

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

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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...

HIF-1-dependent regulation of lifespan in Caenorhabditis elegans by the acyl-CoA-binding protein MAA-1

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Shamalnasab, Mehrnaz; Dhaoui, Manel; Thondamal, Manjunatha

2017-01-01

In yeast, the broadly conserved acyl-CoA-binding protein (ACBP) is a negative regulator of stress resistance and longevity. Here, we have turned to the nematode C. elegans as a model organism in which to determine whether ACBPs play similar roles in multicellular organisms. We systematically...... inactivated each of the seven C. elegans ACBP paralogs and found that one of them, maa-1 (which encodes membrane-associated ACBP 1), is indeed involved in the regulation of longevity. In fact, loss of maa-1 promotes lifespan extension and resistance to different types of stress. Through genetic and gene...... of the proteome. Our work extends to C. elegans the role of ACBP in aging, implicates HIF-1 in the increase of lifespan of maa-1-deficient worms, and sheds light on the anti-aging function of HIF-1. Given that both ACBP and HIF-1 are highly conserved, our results suggest the possible involvement of these proteins...

Digoxin Downregulates NDRG1 and VEGF through the Inhibition of HIF-1α under Hypoxic Conditions in Human Lung Adenocarcinoma A549 Cells

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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.

Triiodothyronine (T3) induces HIF1A and TGFA expression in MCF7 cells by activating PI3K.

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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.

Increased size of solid organs in patients with Chuvash polycythemia and in mice with altered expression of HIF-1α and HIF-2α

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Yoon, Donghoon; Okhotin, David V.; Kim, Bumjun; Okhotina, Yulia; Okhotin, Daniel J.; Miasnikova, Galina Y.; Sergueeva, Adelina I.; Polyakova, Lydia A.; Maslow, Alexei; Lee, Yonggu; Semenza, Gregg L.; Prchal, Josef T.

2010-01-01

Chuvash polycythemia, the first hereditary disease associated with dysregulated oxygen-sensing to be recognized, is characterized by a homozygous germ-line loss-of-function mutation of the VHL gene (VHLR200W) resulting in elevated hypoxia inducible factor (HIF)-1α and HIF-2α levels, increased red cell mass and propensity to thrombosis. Organ volume is determined by the size and number of cells, and the underlying molecular control mechanisms are not fully elucidated. Work from several groups has demonstrated that the proliferation of cells is regulated in opposite directions by HIF-1α and HIF-2α. HIF-1α inhibits cell proliferation by displacing MYC from the promoter of the gene encoding the cyclin-dependent kinase inhibitor, p21Cip1, thereby inducing its expression. In contrast, HIF-2α promotes MYC activity and cell proliferation. Here we report that the volumes of liver, spleen, and kidneys relative to body mass were larger in 30 individuals with Chuvash polycythemia than in 30 matched Chuvash controls. In Hif1a+/− mice, which are heterozygous for a null (knockout) allele at the locus encoding HIF-1α, hepatic HIF-2α mRNA was increased (2-fold) and the mass of the liver was increased, compared with wild-type littermates, without significant difference in cell volume. Hepatic p21Cip1 mRNA levels were 9.5-fold lower in Hif1a+/− mice compared with wild-type littermates. These data suggest that, in addition to increased red cell mass, the sizes of liver, spleen, and kidneys are increased in Chuvash polycythemia. At least in the liver, this phenotype may result from increased HIF-2α and decreased p21Cip1 levels leading to increased hepatocyte proliferation. PMID:20140661

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

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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.

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

6-Mercaptopurine, an activator of Nur77, enhances transcriptional activity of HIF-1alpha resulting in new vessel formation.

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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.

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

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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.

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

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.

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

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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.

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}

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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.)

Dexamethasone impairs hypoxia-inducible factor-1 function

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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

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.

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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.

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

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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.

β2-Adrenergic Receptor-Mediated HIF-1α Upregulation Mediates Blood Brain Barrier Damage in Acute Cerebral Ischemia

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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.

Bile acids destabilise HIF-1α and promote anti-tumour phenotypes in cancer cell models

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Phelan, J. P.; Reen, F. J.; Dunphy, N.; O'Connor, R.; O'Gara, F.

2016-01-01

The role of the microbiome has become synonymous with human health and disease. Bile acids, as essential components of the microbiome, have gained sustained credibility as potential modulators of cancer progression in several disease models. At physiological concentrations, bile acids appear to influence cancer phenotypes, although conflicting data surrounds their precise physiological mechanism of action. Previously, we demonstrated bile acids destabilised the HIF-1α subunit of the Hypoxic-Inducible Factor-1 (HIF-1) transcription factor. HIF-1 overexpression is an early biomarker of tumour metastasis and is associated with tumour resistance to conventional therapies, and poor prognosis in a range of different cancers. Here we investigated the effects of bile acids on the cancer growth and migratory potential of cell lines where HIF-1α is known to be active under hypoxic conditions. HIF-1α status was investigated in A-549 lung, DU-145 prostate and MCF-7 breast cancer cell lines exposed to bile acids (CDCA and DCA). Cell adhesion, invasion, migration was assessed in DU-145 cells while clonogenic growth was assessed in all cell lines. Intracellular HIF-1α was destabilised in the presence of bile acids in all cell lines tested. Bile acids were not cytotoxic but exhibited greatly reduced clonogenic potential in two out of three cell lines. In the migratory prostate cancer cell line DU-145, bile acids impaired cell adhesion, migration and invasion. CDCA and DCA destabilised HIF-1α in all cells and significantly suppressed key cancer progression associated phenotypes; clonogenic growth, invasion and migration in DU-145 cells. These findings suggest previously unobserved roles for bile acids as physiologically relevant molecules targeting hypoxic tumour progression

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

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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.

Structural Insights into the Association of Hif1 with Histones H2A-H2B Dimer and H3-H4 Tetramer.

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Zhang, Mengying; Liu, Hejun; Gao, Yongxiang; Zhu, Zhongliang; Chen, Zijun; Zheng, Peiyi; Xue, Lu; Li, Jixi; Teng, Maikun; Niu, Liwen

2016-10-04

Histone chaperones are critical for guiding specific post-transcriptional modifications of histones, safeguarding the histone deposition (or disassociation) of nucleosome (dis)assembly, and regulating chromatin structures to change gene activities. HAT1-interacting factor 1 (Hif1) has been reported to be an H3-H4 chaperone and to be involved in telomeric silencing and nucleosome (dis)assembly. However, the structural basis for the interaction of Hif1 with histones remains unknown. Here, we report the complex structure of Hif1 binding to H2A-H2B for uncovering the chaperone specificities of Hif1 on binding to both the H2A-H2B dimer and the H3-H4 tetramer. Our findings reveal that Hif1 interacts with the H2A-H2B dimer and the H3-H4 tetramer via distinct mechanisms, suggesting that Hif1 is a pivotal scaffold on alternate binding of H2A-H2B and H3-H4. These specificities are conserved features of the Sim3-Hif1-NASP interrupted tetratricopeptide repeat proteins, which provide clues for investigating their potential roles in nucleosome (dis)assembly. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

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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

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

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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.

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

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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.

MicroRNA-101 negatively regulates Ezh2 and its expression is modulated by androgen receptor and HIF-1α/HIF-1β

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Xu Jianfeng

2010-05-01

Full Text Available Abstract Background In prostate cancer (PCa, the common treatment involving androgen ablation alleviates the disease temporarily, but results in the recurrence of highly aggressive and androgen-independent metastatic cancer. Therefore, more effective therapeutic approaches are needed. It is known that aberrant epigenetics contributes to prostate malignancy. Unlike genetic changes, these epigenetic alterations are reversible, which makes them attractive targets in PCa therapy to impede cancer progression. As a histone methyltransferease, Ezh2 plays an essential role in epigenetic regulation. Since Ezh2 is overexpressed and acts as an oncogene in PCa, it has been proposed as a bona fide target of PCa therapy. MicroRNAs (miRNAs regulate gene expression through modulating protein translation. Recently, the contribution of miRNAs in cancer development is increasingly appreciated. In this report, we present our study showing that microRNA-101 (miR-101 inhibits Ezh2 expression and differentially regulates prostate cancer cells. In addition, the expression of miR-101 alters upon androgen treatment and HIF-1α/HIF-1β induction. Result In our reporter assays, both miR-101 and miR-26a inhibit the expression of a reporter construct containing the 3'-UTR of Ezh2. When ectopically expressed in PC-3, DU145 and LNCaP cells, miR-101 inhibits endogenous Ezh2 expression in all three cell lines, while miR-26a only decreases Ezh2 in DU145. Ectopic miR-101 reduces the invasion ability of PC-3 cells, while restored Ezh2 expression rescues the invasiveness of PC-3 cells. Similarly, miR-101 also inhibits cell invasion and migration of DU145 and LNCaP cells, respectively. Interestingly, ectopic miR-101 exhibits differential effects on the proliferation of PC-3, DU-145 and LNCaP cells and also causes morphological changes of LNCaP cells. In addition, the expression of miR-101 is regulated by androgen receptor and HIF-1α/HIF-1β. While HIF-1α/HIF-1β induced by

HIF-1α inhibition blocks the cross talk between multiple myeloma plasma cells and tumor microenvironment

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Borsi, Enrica, E-mail: enrica.borsi2@unibo.it [Department of Experimental Diagnostic and Specialty Medicine (DIMES), “L. and A. Seràgnoli”, Bologna University School of Medicine, S. Orsola' s University Hospital (Italy); Perrone, Giulia [Fondazione IRCCS Istituto Nazionale dei Tumori, Hematology Department, Via Venezian 1, 20133 Milano (Italy); Terragna, Carolina; Martello, Marina; Zamagni, Elena; Tacchetti, Paola; Pantani, Lucia; Brioli, Annamaria; Dico, Angela Flores; Zannetti, Beatrice Anna; Rocchi, Serena; Cavo, Michele [Department of Experimental Diagnostic and Specialty Medicine (DIMES), “L. and A. Seràgnoli”, Bologna University School of Medicine, S. Orsola' s University Hospital (Italy)

2014-11-01

Multiple myeloma (MM) is a malignant disorder of post-germinal center B cells, characterized by the clonal proliferation of malignant plasma cells (PCs) within the bone marrow (BM). The reciprocal and complex interactions that take place between the different compartments of BM and the MM cells result in tumor growth, angiogenesis, bone disease, and drug resistance. Given the importance of the BM microenvironment in MM pathogenesis, we investigated the possible involvement of Hypoxia-Inducible transcription Factor-1 alpha (HIF-1α) in the PCs-bone marrow stromal cells interplay. To test this hypothesis, we used EZN-2968, a 3rd generation antisense oligonucleotide against HIF-1α, to inhibit HIF-1α functions. Herein, we provide evidence that the interaction between MM cells and BM stromal cells is drastically reduced upon HIF-1α down-modulation. Notably, we showed that upon exposure to HIF-1α inhibitor, neither the incubation with IL-6 nor the co-culture with BM stromal cells were able to revert the anti-proliferative effect induced by EZN-2968. Moreover, we observed a down-modulation of cytokine-induced signaling cascades and a reduction of MM cells adhesion capability to the extracellular matrix proteins in EZN-2968-treated samples. Taken together, these results strongly support the concept that HIF-1α plays a critical role in the interactions between bone BM cells and PCs in Multiple Myeloma. - Highlights: • HIF-1α inhibition induces a mild apoptotic cell death. • Down-modulation of cytokine-induced signaling cascades upon HIF-1α inhibition. • Reduced interaction between MM cells and BMSCs upon HIF-1α down-modulation. • Reduced PCs adhesion to the extracellular matrix protein induced by EZN-2968. • HIF-1α inhibition may be an attractive therapeutic strategy for Multiple Myeloma.

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

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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.

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

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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.

HIF-1α is essential for effective PMN bacterial killing, antimicrobial peptide production and apoptosis in Pseudomonas aeruginosa keratitis.

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Elizabeth A Berger

Full Text Available 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 antagonist (17-DMAG, the role of HIF-1α was assessed in P. aeruginosa-infected BALB/c mice. Clinical score and slit lamp photography indicated HIF-1α inhibition exacerbated disease and corneal destruction. Real time RT-PCR, immunohistochemistry, ELISA, Greiss and MPO assays, bacterial load, intracellular killing, phagocytosis and apoptosis assays further tested the regulatory role of HIF-1α. Despite increased pro-inflammatory cytokine expression and increased MPO levels after knocking down HIF-1α expression, in vivo studies revealed a decrease in NO production and higher bacterial load. In vitro studies using PMN provided evidence that although inhibition of HIF-1α did not affect phagocytosis, both bacterial killing and apoptosis were significantly affected, as was production of antimicrobial peptides. Overall, data provide evidence that inhibition of HIF-1α converts a normally resistant disease response to susceptible (corneal thinning and perforation after induction of bacterial keratitis. Although this inhibition does not appear to affect PMN transmigration or phagocytosis, both in vivo and in vitro approaches indicate that the transcriptional factor is essential for effective bacterial killing, apoptosis and antimicrobial peptide production.

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

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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.

Vanillin Suppresses Cell Motility by Inhibiting STAT3-Mediated HIF-1α mRNA Expression in Malignant Melanoma Cells.

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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.

ON THE PRO-METASTATIC STRESS RESPONSE TO CANCER THERAPIES: EVIDENCE FOR A POSITIVE CO-OPERATION BETWEEN TIMP-1, HIF-1α, AND miR-210

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Haissi eCui

2012-07-01

Full Text Available In contrast to expectations in the past that tumor starvation or unselective inhibition of proteolytic activity would cure cancer, there is accumulating evidence that microenvironmental stress, such as hypoxia or broad spectrum inhibition of metalloproteinases can promote metastasis. In fact, malignant tumor cells, due to their genetic and epigenetic instability, are predisposed to react to stress by adaptation and, if the stress persists, by escape and formation of metastasis. Recent recognition of the concepts of dynamic evolution as well as population and systems biology is extremely helpful to understand the disappointments of clinical trials with new drugs and may lead to paradigm-shifts in therapy strategies. This must be complemented by an increased understanding of molecular mechanism involved in stress response. Here, we review new roles of Hypoxia-inducible factor-1 (HIF-1, one transcription factor regulating stress response-related gene expression: HIF-1 is crucial for invasion and metastasis, independent from its pro-survival function. In addition, HIF-1 mediates pro-metastatic microenvironmental changes of the proteolytic balance as triggered by high systemic levels of tissue inhibitor of metalloproteinases-1 (TIMP-1, typical for many aggressive cancers, and regulates the metabolic switch to glycolysis, notably via activation of the microRNA miR-210. There is preliminary evidence that TIMP-1 also induces miR-210. Such positive-regulatory co-operation of HIF-1α, miR-210, and TIMP-1, all described to correlate with bad prognosis of cancer patients, opens new perspectives of gaining insight into molecular mechanisms of metastasis-inducing evasion of tumor cells from stress.

HIF-1α as a Regulator of BMP2-Induced Chondrogenic Differentiation, Osteogenic Differentiation, and Endochondral Ossification in Stem Cells

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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.

Limitation of HIF-1α with pentoxifillyne on renal tubular ischemia result of hiperoxaluria and ESWL.

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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.

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

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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

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.

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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.

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

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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

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

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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.

Radiation enhancement effect of RNA interference for HIF-1α on the transplant tumor

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Ren Ruimei; Sun Xindong; Zhao Hanxi; Yan Qingxia; Huang Guangwu

2008-01-01

Objective: To determine and explore the radiation enhancement of RNA interference for HIF-1α on the transplant tumor using polycationic polyethylenimine (PEI), as a new kind of gene vector. Methods: SPCA-1 nude mouse model was used. 160 nude mice bearing SPCA-1 were randomly divided into 4 treated groups and 1 control groups, each group had 32 mice. The expression of HIF-1α was studied by immunohistochemical method after RNA interference for HIF-1α. The differences of the volume, weight, survival time of the transplant tumor were studied among the simple radiation group, the simple RNA interference for HIF- 1α group and the combination of radiation and RNA interference for HIF-1α. Results: The expression of HIF-1α was decreased after RNA interference for HIF-1α. RNA interference for HIF-1α combined with radiation decreased the volume, weight of the transplant tumor, and prolonged its survival time period significantly than other methods. Conclusions: RNA interference targeting HIF-1α might enhance the radiosensitivity of the transplant tumor using PEI as a new kind of gene vector in vitro. (authors)

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

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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.)

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.)

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

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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.

Novel mechanism of cardiac protection by valsartan: synergetic roles of TGF-β1 and HIF-1α in Ang II-mediated fibrosis after myocardial infarction.

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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

Reactive oxygen species-driven HIF1α triggers accelerated glycolysis in endothelial cells exposed to low oxygen tension

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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.

Role for HIF-1α and Downstream Pathways in Regulating Neuronal Injury after Intracerebral Hemorrhage in Diabetes

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Zhen Yu

2015-08-01

Full Text Available Background/Aims: HIF-1α is accumulated in the cellular nucleus and cytoplasm under conditions of oxygen deprivation and engaged in pathophysiologic changes of homeostasis by modulating the expression of several target genes. As an endogenous signaling protein, HIF-1α contributes to in neuroprotection, erythropoiesis, and apoptosis modulation. The purpose of this study was to examine the role played by HIF-1α in regulating neurological injury evoked by intracerebral hemorrhage (ICH through its downstream product, namely vascular endothelial growth factor (VEGF. In particular, we examined the effects of diabetic hyperglycemia on HIF-1α response in the processing of ICH. Methods: ELISA was used to measure HIF-1α and VEGF; and Western Blot analysis to examine the protein expression of VEGFR-2 and Caspase-3. Neurological Severity Score and brain water content were used to indicate neurological function and brain edema. Results: HIF-1α and VEGF were significantly increased in the brain after induction of ICH in non-diabetic control rats and diabetic rats; however, the amplified levels of HIF-1α and VEGF were attenuated in diabetic rats (Pvs. non-diabetic rats as compared with non-diabetic rats. Also, the protein expression of VEGF receptor subtype 2 was significantly less in the brain of diabetic rats (Pvs. non-diabetic rats. Further, cerebral infusion of HIF-1 activator stabilized VEGF levels, attenuated Caspase-3 and improved neurological deficits induced by ICH and the effects are smaller in diabetic animals. Conclusion: HIF-1α activated by ICH likely plays a beneficial role via VEGF mechanisms and response of HIF-1α is largely impaired in diabetes. This has pharmacological implications to target specific HIF-1α and VEGF pathway for neuronal dysfunction and vulnerability related to ICH.

Strategies To Assess Hypoxic/HIF-1-Active Cancer Cells for the Development of Innovative Radiation Therapy

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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

Strategies To Assess Hypoxic/HIF-1-Active Cancer Cells for the Development of Innovative Radiation Therapy

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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.

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

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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.

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

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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.

Isoflurane Preconditioning Increases Survival of Rat Skin Random-Pattern Flaps by Induction of HIF-1α Expression

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Yu Sun

2013-04-01

Full Text Available Background: Survival of random-pattern skin flaps is important for the success of plastic and reconstructive surgeries. This study investigates isoflurane-induced protection against ischemia of skin flap and the underlying molecular mechanism in this process. Methods: Human umbilical vein endothelial cells (HUVECs and human skin fibroblast cells were exposed to isoflurane for 4 h. Expression of hypoxia inducible factor-1α (HIF-1α, heme oxygenase-1 (HO-1 and vascular endothelial growth factor (VEGF were analyzed up to 24 h post isoflurane exposure using qRT-PCR and western blot, or ELISA analyses. PI3K inhibitors - LY 294002 and wortmannin, mTOR inhibitor - rapamycin, and GSK3β inhibitor - SB 216763 were used respectively to assess the effects of isoflurane treatment and HIF-1α expression. Furthermore, 40 rats were randomly divided into 5 groups (control, isoflurane, scrambled siRNA plus isoflurane, HIF-1α siRNA plus isoflurane, and DMOG and subjected to random-pattern skin flaps operation. Rats were prepared for evaluation of flap survival and full-feld laser perfusion imager (FLPI (at 7 day and microvessel density evaluation (at 10 day. Results: Isoflurane exposure induced expression of HIF-1α protein, HO-1 and VEGF mRNA and proteins in a time-dependent manner. Both LY 294002 and wortmannin inhibited phospho-Akt, phospho-mTOR, phospho-GSK 3β and HIF-1α expression after isoflurane exposure. Both wortmannin and rapamycin inhibited isoflurane-induced phospho-4E-BP1 (Ser 65 and phospho-P70s6k (Thr 389 and HIF-1α expression. SB 216763 pre-treatment could further enhance isoflurane-induced expression of phospho-GSK 3β (Ser 9 and HIF-1α protein compared to the isoflurane-alone cells. In animal experiments, isoflurane alone, scrambled siRNA plus isoflurane, or DMOG groups had significantly upregulated vascularity and increased survival of the skin flaps compared to the controls. However, HIF-1α knockdown abrogated the protective effect of

The Long Non-coding RNA HIF1A-AS2 Facilitates the Maintenance of Mesenchymal Glioblastoma Stem-like Cells in Hypoxic Niches

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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.

Albendazole inhibits HIF-1α-dependent glycolysis and VEGF expression in non-small cell lung cancer cells.

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Zhou, Fang; Du, Jin; Wang, Jianjun

2017-04-01

Albendazole (ABZ) has an anti-tumor ability and inhibits HIF-1α activity. HIF-1α is associated with glycolysis and vascular endothelial cell growth factor (VEGF) expression, which plays an important role in cancer progression. These clues indicate that ABZ exerts an anti-cancer effect by regulating glycolysis and VEGF expression. The aim of this study is to clarify the effects of ABZ on non-small cell lung cancer (NSCLC) cells and explore the underlying molecular mechanisms. The expression levels of HIF-1α and VEGF were detected using western blot analysis, and the effect of ABZ on glycolysis was evaluated by measuring the relative activities of hexokinase (HK), pyruvate kinase (PK), and lactate dehydrogenase (LDH) and detecting the production of lactate in A549 and H1299 cells. The results showed that ABZ decreased the expression levels of HIF-1α and VEGF and suppressed glycolysis in under hypoxia, but not normoxic condition. Inhibiting HIF-1α also suppressed glycolysis and VEGF expression. Additionally, ABZ inhibited the volume and weight, decreased the relative activities of HK, PK, and LDH, and reduced the levels of HIF-1α and VEGF of A549 xenografts in mouse models. In conclusion, ABZ inhibited growth of NSCLC cells by suppressing HIF-1α-dependent glycolysis and VEGF expression.

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.

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

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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

ECM-dependent HIF induction directs trophoblast stem cell fate via LIMK1-mediated cytoskeletal rearrangement.

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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.

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

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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.

Inhibition of HIF-1α decreases expression of pro-inflammatory IL-6 and TNF-α in diabetic retinopathy.

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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.

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

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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

Egr-1 and serum response factor are involved in growth factors- and serum-mediated induction of E2-EPF UCP expression that regulates the VHL-HIF pathway.

Science.gov (United States)

Lim, Jung Hwa; Jung, Cho-Rok; Lee, Chan-Hee; Im, Dong-Soo

2008-11-01

E2-EPF ubiquitin carrier protein (UCP) has been shown to be highly expressed in common human cancers and target von Hippel-Lindau (VHL) for proteosomal degradation in cells, thereby stabilizing hypoxia-inducible factor (HIF)-1alpha. Here, we investigated cellular factors that regulate the expression of UCP gene. Promoter deletion assay identified binding sites for early growth response-1 (Egr-1) and serum response factor (SRF) in the UCP promoter. Hepatocyte or epidermal growth factor (EGF), or phorbol 12-myristate 13-acetate induced UCP expression following early induction of Egr-1 expression in HeLa cells. Serum increased mRNA and protein levels of SRF and UCP in the cell. By electrophoretic mobility shift and chromatin immunoprecipitation assays, sequence-specific DNA-binding of Egr-1 and SRF to the UCP promoter was detected in nuclear extracts from HeLa cells treated with EGF and serum, respectively. Overexpression of Egr-1 or SRF increased UCP expression. RNA interference-mediated depletion of endogenous Egr-1 or SRF impaired EGF- or serum-mediated induction of UCP expression, which was required for cancer cell proliferation. Systemic delivery of EGF into mice also increased UCP expression following early induction of Egr-1 expression in mouse liver. The induced UCP expression by the growth factors or serum increased HIF-1alpha protein level under non-hypoxic conditions, suggesting that the Egr-1/SRF-UCP-VHL pathway is in part responsible for the increased HIF-1alpha protein level in vitro and in vivo. Thus, growth factors and serum induce expression of Egr-1 and SRF, respectively, which in turn induces UCP expression that positively regulates cancer cell growth.

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

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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.

Development of a Combination Therapy for Prostate Cancer by Targeting Stat3 and HIF-1alpha

Science.gov (United States)

2013-07-01

inflammation-induced cancer, making it an attractive target (25-27). A3. Innovation 1. TEL03 is a novel anti-cancer agent from Chinese herbal medicine ...agents from Chinese herbal medicine (CHM) that targets HIF-1α /2α for prostate cancer therapy. Hypoxia orchestrated by HIF-1αis crucial for tumor...Stat3 for treatment of prostate and other cancers. TEL03, which is a novel anti-cancer agent derived from Chinese herbal medicine (CHM: Hypocrella

HIF1α is a regulator of hematopoietic progenitor and stem cell development in hypoxic sites of the mouse embryo

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Parisa Imanirad

2014-01-01

Full Text Available Hypoxia affects many physiologic processes during early stages of mammalian ontogeny, particularly placental and vascular development. In the adult, the hypoxic bone marrow microenvironment plays a role in regulating hematopoietic stem cell (HSC function. HSCs are generated from the major vasculature of the embryo, but whether the hypoxic response affects the generation of these HSCs is as yet unknown. Here we examined whether Hypoxia Inducible Factor1-alpha (HIF1α, a key modulator of the response to hypoxia, is essential for HSC development. We found hypoxic cells in embryonic tissues that generate and expand hematopoietic cells (aorta, placenta and fetal liver, and specifically aortic endothelial and hematopoietic cluster cells. A Cre/loxP conditional knockout (cKO approach was taken to delete HIF1α in Vascular Endothelial-Cadherin expressing endothelial cells, the precursors to definitive hematopoietic cells. Functional assays show that HSC and hematopoietic progenitor cells (HPCs are significantly reduced in cKO aorta and placenta. Moreover, decreases in phenotypic aortic hematopoietic cluster cells in cKO embryos indicate that HIF1α is necessary for generation and/or expansion of HPCs and HSCs. cKO adult BM HSCs are also affected under transplantation conditions. Thus, HIF1α is a regulator of HSC generation and function beginning at the earliest embryonic stages.

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

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.

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.

The dietary flavonoid kaempferol effectively inhibits HIF-1 activity and hepatoma cancer cell viability under hypoxic conditions

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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.

HIF1α protein and mRNA expression as a new marker for post mortem interval estimation in human gingival tissue.

Science.gov (United States)

Fais, Paolo; Mazzotti, Maria Carla; Teti, Gabriella; Boscolo-Berto, Rafael; Pelotti, Susi; Falconi, Mirella

2018-06-01

Estimating the post mortem interval (PMI) is still a crucial step in Forensic Pathology. Although several methods are available for assessing the PMI, a precise estimation is still quite unreliable and can be inaccurate. The present study aimed to investigate the immunohistochemical distribution and mRNA expression of hypoxia inducible factor (HIF-1α) in post mortem gingival tissues to establish a correlation between the presence of HIF-1α and the time since death, with the final goal of achieving a more accurate PMI estimation. Samples of gingival tissues were obtained from 10 cadavers at different PMIs (1-3 days, 4-5 days and 8-9 days), and were processed for immunohistochemistry and quantitative reverse transcription-polymerase chain reaction. The results showed a time-dependent correlation of HIF-1α protein and its mRNA with different times since death, which suggests that HIF-1α is a potential marker for PMI estimation. The results showed a high HIF-1α protein signal that was mainly localized in the stratum basale of the oral mucosa in samples collected at a short PMI (1-3 days). It gradually decreased in samples collected at a medium PMI (4-5 days), but it was not detected in samples collected at a long PMI (8-9 days). These results are in agreement with the mRNA data. These data indicate an interesting potential utility of Forensic Anatomy-based techniques, such as immunohistochemistry, as important complementary tools to be used in forensic investigations. © 2018 The Authors. Journal of Anatomy published by John Wiley & Sons Ltd on behalf of Anatomical Society.

IL-1β upregulates Muc5ac expression via NF-κB-induced HIF-1α in asthma.

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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

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

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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

MicroRNA 107 partly inhibits endothelial progenitor cells differentiation via HIF-1β.

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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.

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

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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

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

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

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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.

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

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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.

HIF-1α Activation Attenuates IL-6 and TNF-α Pathways in Hippocampus of Rats Following Transient Global Ischemia

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Jihong Xing

2016-07-01

Full Text Available Background/Aims: This study was to examine the role played by hypoxia inducible factor-1 (HIF-1α in regulating pro-inflammatory cytokines (PICs pathway in the rat hippocampus after cardiac arrest (CA induced-transient global ischemia followed by cardiopulmonary resuscitation (CPR. Those PICs include interleukin-1β (IL-1β, interleukin-6 (IL-6 and tumor necrosis factor-α (TNF-α. Methods: A rat model of CA induced by asphyxia was used in the current study. Following CPR, the hippocampus CA1 region was obtained for ELISA to determine the levels of HIF-1α and PICs; and Western Blot analysis to determine the protein levels of PIC receptors. Results: Our data show that IL-1β, IL-6 and TNF-α were significant elevated in the hippocampus after CPR as compared with control group. This was companied with increasing of HIF-1α and the time courses for HIF-1α and PICs were similar. In addition, PIC receptors, namely IL-1R, IL-6R and TNFR1 were upregulated in CA rats. Also, stimulation of HIF-1α by systemic administration of ML228, HIF-1α activator, significantly attenuated the amplified IL-6/IL-6R and TNF-α /TNFR1 pathway in the hippocampus of CA rats, but did not modify IL-1β and its receptor. Moreover, ML228 attenuated upregulated expression of Caspase-3 indicating cell apoptosis evoked by CA. Conclusion: Transient global ischemia induced by CA increases the levels of IL-1β, IL-6 and TNF-α and thereby leads to enhancement in their respective receptor in the rat hippocampus. Stabilization of HIF-1α plays a role in attenuating amplified expression IL-6R, TNFR1 and Caspase-3 in the processing of transient global ischemia. Results of our study suggest that PICs contribute to cerebral injuries evoked by transient global ischemia and in this pathophysiological process activation of HIF-1α improves tissues against ischemic injuries. Our data revealed specific signaling pathways in alleviating CA-evoked global cerebral ischemia by elucidating that

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...

Involvement of HIF-1α activation in the doxorubicin resistance of human osteosarcoma cells.

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Roncuzzi, Laura; Pancotti, Fabia; Baldini, Nicola

2014-07-01

Osteosarcoma is the most common primary bone cancer in children and adolescents. Despite aggressive treatment regimens, survival outcomes remain unsatisfactory, particularly in patients with metastatic and/or recurrent disease. Unfortunately, treatment failure is commonly due to the development of chemoresistance, for which the underlying molecular mechanisms remain unclear. The aim of the present study was to investigate the role of hypoxia-inducible factor 1α (HIF‑1α) and its signalling pathways as mediators of drug-resistance in human osteosarcoma. Toward this aim, we established two osteosarcoma cell lines selected for resistance to doxorubicin, a drug of choice in the treatment of this tumour. Our results showed that the multidrug resistance (MDR) phenotype was also mediated by HIF-1α, the most important regulator of cell adaptation to hypoxia. Our data showed that this transcription factor promoted the outward transport of intracellular doxorubicin by activating the P-glycoprotein (P-gp) expression in osteosarcoma cells maintained in normoxic conditions. In addition, it hindered doxorubicin-induced apoptosis by regulating the expression of c-Myc and p21. Finally, we observed that the doxorubicin-resistant cells maintained for 2 months of continuous culture in a drug-free medium, lost their drug-resistance and this effect was associated with the absence of HIF-1α expression. The emerging role of HIF-1α in osteosarcoma biology indicates its use as a valuable therapeutic target.

Endothelial HIF-1α Enables Hypothalamic Glucose Uptake to Drive POMC Neurons.

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Varela, Luis; Suyama, Shigetomo; Huang, Yan; Shanabrough, Marya; Tschöp, Matthias H; Gao, Xiao-Bing; Giordano, Frank J; Horvath, Tamas L

2017-06-01

Glucose is the primary driver of hypothalamic proopiomelanocortin (POMC) neurons. We show that endothelial hypoxia-inducible factor 1α (HIF-1α) controls glucose uptake in the hypothalamus and that it is upregulated in conditions of undernourishment, during which POMC neuronal activity is decreased. Endothelium-specific knockdown of HIF-1α impairs the ability of POMC neurons to adapt to the changing metabolic environment in vivo, resulting in overeating after food deprivation in mice. The impaired functioning of POMC neurons was reversed ex vivo or by parenchymal glucose administration. These observations indicate an active role for endothelial cells in the central control of metabolism and suggest that central vascular impairments may cause metabolic disorders. © 2017 by the American Diabetes Association.

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.

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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.

Overexpression of HIF-1α in mesenchymal stem cells contributes to repairing hypoxic-ischemic brain damage in rats.

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Lin, Deju; Zhou, Liping; Wang, Biao; Liu, Lizhen; Cong, Li; Hu, Chuanqin; Ge, Tingting; Yu, Qin

2017-01-01

Preclinical researches on mesenchymal stem cells (MSCs) transplantation, which is used to treat hypoxic-ischemic (HI) brain damage, have received inspiring achievements. However, the insufficient migration of active cells to damaged tissues has limited their potential therapeutic effects. There are some evidences that hypoxia inducible factor-1 alpha (HIF-1α) promotes the viability and migration of the cells. Here, we aim to investigate whether overexpression of HIF-1α in MSCs could improve the viability and migration capacity of cells, and its therapeutic efficiency on HI brain damage. In the study, MSCs with HIF-1α overexpression was achieved by recombinant lentiviral vector and transplanted to the rats subsequent to HI. Our data indicated that overexpression of HIF-1α promoted the viability and migration of MSCs, HIF-1α overexpressed MSCs also had a stronger therapeutic efficiency on HI brain damaged treatment by mitigating the injury on behavioral and histological changes evoked by HI insults, accompanied with more MSCs migrating to cerebral damaged area. This study demonstrated that HIF-1α overexpression could increase the MSCs' therapeutic efficiency in HI and the promotion of the cells' directional migration to cerebral HI area by overexpression may be responsible for it, which showed that transplantation of MSCs with HIF-1α overexpression is an attractive therapeutic option to treat HI-induced brain injury in the future. Copyright © 2016 Académie des sciences. Published by Elsevier SAS. All rights reserved.

The dietary flavonoid kaempferol effectively inhibits HIF-1 activity and hepatoma cancer cell viability under hypoxic conditions.

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Mylonis, Ilias; Lakka, Achillia; Tsakalof, Andreas; Simos, George

2010-07-16

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-1alpha 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-1alpha 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)=5.16microM). The mechanism of this inhibition did not involve suppression of HIF-1alpha protein levels but rather its mislocalization into the cytoplasm due to inactivation of p44/42 MAPK by kaempferol (IC(50)=4.75microM). Exposure of Huh7 cells to 10microM 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 (5-10microM) and suppresses hepatocarcinoma cell survival more efficiently under hypoxia. It has, therefore, potential as a therapeutic or chemopreventive anti-HCC agent. Copyright 2010 Elsevier Inc. All rights reserved.

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

Functional cooperation between HIF-1α and c-Jun in mediating primary and acquired resistance to gefitinib in NSCLC cells with activating mutation of EGFR.

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Meng, Shuyan; Wang, Guorui; Lu, Yang; Fan, Zhen

2018-07-01

Hypoxia-inducible factor 1 (HIF-1) and activator protein 1 (AP-1) are important transcription factors regulating expression of genes involved in cell survival. HIF-1α and c-Jun are key components of HIF-1 and AP-1, respectively, and are regulated by epidermal growth factor receptor (EGFR)-mediated cell signaling and tumor microenvironmental cues. The roles of HIF-1α and c-Jun in development of resistance to EGFR tyrosine kinase inhibitor (TKI) in non-small cell lung cancer (NSCLC) with activating mutation of EGFR have not been explored. In this study, we investigated the roles of HIF-1α and c-Jun in mediating primary and acquired resistance to gefitinib in NSCLC cells with activating mutation of EGFR. Changes in HIF-1α protein and in total and phosphorylated c-Jun levels in relation to changes in total and phosphorylated EGFR levels before and after gefitinib treatment were measured using Western blot analysis in NSCLC cells sensitive or resistant to gefitinib. The impact of overexpression of a constitutively expressed HIF-1α (HIF-1α/ΔODD) or a constitutively active c-Jun upstream regulator (SEK1 S220E/T224D mutant) on cell response to gefitinib was also examined. The effect of pharmacological inhibition of SEK1-JNK-c-Jun pathway on cell response to gefitinib was evaluated. Downregulation of HIF-1α and total and phosphorylated c-Jun levels correlated with cell inhibitory response to gefitinib better than decrease in phosphorylated EGFR did in NSCLC cells with intrinsic or acquired resistance to gefitinib. Overexpression of HIF-1α/ΔODD or SEK1 S220E/T224D mutant conferred resistance to gefitinib. There exists a positive feed-forward regulation loop between HIF-1 and c-Jun. The JNK inhibitor SP600125 sensitized gefitinib-resistant NSCLC cells to gefitinib. HIF-1α and c-Jun functionally cooperate in development of resistance to gefitinib in NSCLC cells. The translational value of inhibiting HIF-1α/c-Jun cooperation in overcoming resistance to EGFR TKI

HIF-1{alpha} is necessary to support gluconeogenesis during liver regeneration

Energy Technology Data Exchange (ETDEWEB)

Tajima, Toshihide [Department of Obstetrics and Gynecology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Goda, Nobuhito, E-mail: goda@waseda.jp [Department of Life Science and Medical Bio-Science, School of Advanced Science and Engineering, Waseda University, TWIns 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480 (Japan); Fujiki, Natsuko; Hishiki, Takako; Nishiyama, Yasumasa [Department of Biochemistry and Integrative Medical Biology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Senoo-Matsuda, Nanami [Department of Life Science and Medical Bio-Science, School of Advanced Science and Engineering, Waseda University, TWIns 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480 (Japan); Shimazu, Motohide [Department of Surgery, Tokyo Medical University Hachioji Medical Center, 1163 Tatemachi, Hachioji, Tokyo 193-0998 (Japan); Soga, Tomoyoshi [The Institute for Advanced Biosciences, Keio University, Tsuruoka City, Yamagata 997-0052 (Japan); Yoshimura, Yasunori [Department of Obstetrics and Gynecology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Johnson, Randall S. [Molecular Biology Section, Division of Biology, University of California, San Diego, La Jolla, CA 92093 (United States); Suematsu, Makoto [Department of Biochemistry and Integrative Medical Biology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan)

2009-10-02

Coordinated recovery of hepatic glucose metabolism is prerequisite for normal liver regeneration. To examine roles of hypoxia inducible factor-1{alpha} (HIF-1{alpha}) for hepatic glucose homeostasis during the reparative process, we inactivated the gene in hepatocytes in vivo. Following partial hepatectomy (PH), recovery of residual liver weight was initially retarded in the mutant mice by down-regulation of hepatocyte proliferation, but occurred comparably between the mutant and control mice at 72 h after PH. At this time point, the mutant mice showed lowered blood glucose levels with enhanced accumulation of glycogen in the liver. The mutant mice exhibited impairment of hepatic gluconeogenesis as assessed by alanine tolerance test. This appeared to result from reduced expression of PGK-1 and PEPCK since 3-PG, PEP and malate were accumulated to greater extents in the regenerated liver. In conclusion, these findings provide evidence for roles of HIF-1{alpha} in the regulation of gluconeogenesis under liver regeneration.

HIF-1α is necessary to support gluconeogenesis during liver regeneration