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Sample records for hypoxia-inducible factor induces

  1. Structural integration in hypoxia-inducible factors

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Dalei; Potluri, Nalini; Lu, Jingping; Kim, Youngchang; Rastinejad, Fraydoon

    2015-08-20

    The hypoxia-inducible factors (HIFs) coordinate cellular adaptations to low oxygen stress by regulating transcriptional programs in erythropoiesis, angiogenesis and metabolism. These programs promote the growth and progression of many tumours, making HIFs attractive anticancer targets. Transcriptionally active HIFs consist of HIF-alpha and ARNT (also called HIF-1 beta) subunits. Here we describe crystal structures for each of mouse HIF-2 alpha-ARNT and HIF-1 alpha-ARNT heterodimers in states that include bound small molecules and their hypoxia response element. A highly integrated quaternary architecture is shared by HIF-2 alpha-ARNT and HIF-1 alpha-ARNT, wherein ARNT spirals around the outside of each HIF-alpha subunit. Five distinct pockets are observed that permit small-molecule binding, including PAS domain encapsulated sites and an interfacial cavity formed through subunit heterodimerization. The DNA-reading head rotates, extends and cooperates with a distal PAS domain to bind hypoxia response elements. HIF-alpha mutations linked to human cancers map to sensitive sites that establish DNA binding and the stability of PAS domains and pockets.

  2. Effects of hypoxia-inducible factor 1 on ischemic cerebrovascular disease

    Institute of Scientific and Technical Information of China (English)

    Yongjie Luo; Xiaoping Wang; Hongbin Sun

    2008-01-01

    Hypoxia-inducible factor I, a nuclear transcription factor, is induced by hypoxia. Hypoxia-inducible factor I, a heterodimeric DNA-binding protein, is composed of hypoxia-inducible factor 1α and hypoxia-inducible factor 1 β subunits, which are family members of the basic helix-loop-helix-PER, ARNT, SIM (PAS) protein. O2 concentration regulates hypoxia-inducible factor 1 activity via this subunit. Hypoxia-inducible factor 1α plays a major role in response to hypoxia and transcriptional activation, as well as in the target gene specificity of the DNA enhancer. Hypoxia-inducible factor 1β cannot be induced by hypoxia. This effect may be due to hypoxia-inducible factor 1 stability and activated conformation due to dimerization. Previous studies have shown that hypoxia-inducible factor 1 mRNA expression increases in the penumbra following ischemia/hypoxia. Hypoxia-inducible factor 1 plays an important role in brain tissue injury alter ischemia by affecting a series of target genes, elevating tolerance to hypoxia, and ensuring survival of neural cells. This article summarizes the structure, function, expression, regulatory mechanisms, biological effects, and significance of hypoxia-inducible factor 1 in patients with ischemic cerebrovascular disease. As a transcriptional activator, hypoxia- inducible factor 1 plays a key role in hypoxic responses by stabilizing the internal environment. It also has been shown to regulate the expression of several genes. The regulatory effects of hypoxia-inducible factor 1 in patients with ischemic cerebrovascular disease have been described. The present review re-examined the concept of brain protection at the level of gene regulation.

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

    DEFF Research Database (Denmark)

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

    to a standardized scheme. 2. The prognostic value of HIF-1α is investigated by SNP analysis and HIF-1α expression in tissue from 300 patients operated for colorectal cancer and the results is validated in a prospectively population of 200 patients. 3. The predictive value of HIF-1α will be investigated in patients......Clinical Aspects of Hypoxia-inducible Factors in Colorectal Cancer   Birgitte Mayland Havelund1,4 MD, Karen-Lise Garm Spindler1,4 MD, PhD, Flemming Brandt Sørensen2,4 MD, DMSc, Ivan Brandslund3 MD, DMSc, Anders Jakobsen1,4 MD, DMSc. 1Department of Oncology, 2Pathology and 3Biochemistry, Vejle...... Hospital, Vejle, Denmark 4Institute of Regional Health Services Research, University of Southern Denmark, Odense Denmark Background Prognostic and predictive markers are needed for individualizing the treatment of colorectal cancer. Hypoxia-inducible factor 1α (HIF-1α) is a transcription-inducing factor...

  4. Functional pathway mapping analysis for hypoxia-inducible factors.

    Science.gov (United States)

    Chuang, Chia-Sheng; Pai, Tun-Wen; Hu, Chin-Hua; Tzou, Wen-Shyong; Dah-Tsyr Chang, Margaret; Chang, Hao-Teng; Chen, Chih-Chia

    2011-06-20

    Hypoxia-inducible factors (HIFs) are transcription factors that play a crucial role in response to hypoxic stress in living organisms. The HIF pathway is activated by changes in cellular oxygen levels and has significant impacts on the regulation of gene expression patterns in cancer cells. Identifying functional conservation across species and discovering conserved regulatory motifs can facilitate the selection of reference species for empirical tests. This paper describes a cross-species functional pathway mapping strategy based on evidence of homologous relationships that employs matrix-based searching techniques for identifying transcription factor-binding sites on all retrieved HIF target genes. HIF-related orthologous and paralogous genes were mapped onto the conserved pathways to indicate functional conservation across species. Quantitatively measured HIF pathways are depicted in order to illustrate the extent of functional conservation. The results show that in spite of the evolutionary process of speciation, distantly related species may exhibit functional conservation owing to conservative pathways. The novel terms OrthRate and ParaRate are proposed to quantitatively indicate the flexibility of a homologous pathway and reveal the alternative regulation of functional genes. The developed functional pathway mapping strategy provides a bioinformatics approach for constructing biological pathways by highlighting the homologous relationships between various model species. The mapped HIF pathways were quantitatively illustrated and evaluated by statistically analyzing their conserved transcription factor-binding elements. hypoxia-inducible factor (HIF), hypoxia-response element (HRE), transcription factor (TF), transcription factor binding site (TFBS), KEGG (Kyoto Encyclopedia of Genes and Genomes), cross-species comparison, orthology, paralogy, functional pathway.

  5. Hypoxia-Inducible Factor as an Angiogenic Master Switch

    Science.gov (United States)

    Hashimoto, Takuya; Shibasaki, Futoshi

    2015-01-01

    Hypoxia-inducible factors (HIFs) regulate the transcription of genes that mediate the response to hypoxia. HIFs are constantly expressed and degraded under normoxia, but stabilized under hypoxia. HIFs have been widely studied in physiological and pathological conditions and have been shown to contribute to the pathogenesis of various vascular diseases. In clinical settings, the HIF pathway has been studied for its role in inhibiting carcinogenesis. HIFs might also play a protective role in the pathology of ischemic diseases. Clinical trials of therapeutic angiogenesis after the administration of a single growth factor have yielded unsatisfactory or controversial results, possibly because the coordinated activity of different HIF-induced factors is necessary to induce mature vessel formation. Thus, manipulation of HIF activity to simultaneously induce a spectrum of angiogenic factors offers a superior strategy for therapeutic angiogenesis. Because HIF-2α plays an essential role in vascular remodeling, manipulation of HIF-2α is a promising approach to the treatment of ischemic diseases caused by arterial obstruction, where insufficient development of collateral vessels impedes effective therapy. Eukaryotic initiation factor 3 subunit e (eIF3e)/INT6 interacts specifically with HIF-2α and induces the proteasome inhibitor-sensitive degradation of HIF-2α, independent of hypoxia and von Hippel-Lindau protein. Treatment with eIF3e/INT6 siRNA stabilizes HIF-2α activity even under normoxic conditions and induces the expression of several angiogenic factors, at levels sufficient to produce functional arteries and veins in vivo. We have demonstrated that administration of eIF3e/INT6 siRNA to ischemic limbs or cold-injured brains reduces ischemic damage in animal models. This review summarizes the current understanding of the relationship between HIFs and vascular diseases. We also discuss novel oxygen-independent regulatory proteins that bind HIF-α and the implications

  6. Hypoxia-inducible factor 3 biology: complexities and emerging themes.

    Science.gov (United States)

    Duan, Cunming

    2016-02-15

    The hypoxia-inducible factor (HIF) family has three distinct members in most vertebrates. All three HIFs consist of a unique and oxygen-labile α-subunit and a common and stable β-subunit. While HIF-1 and HIF-2 function as master regulators of the transcriptional response to hypoxia, much less is known about HIF-3. The HIF-3α gene gives rise to multiple HIF-3α variants due to the utilization of different promoters, different transcription initiation sites, and alternative splicing. These HIF-3α variants are expressed in different tissues, at different developmental stages, and are differentially regulated by hypoxia and other factors. Recent studies suggest that different HIF-3α variants have different and even opposite functions. There is strong evidence that full-length HIF-3α protein functions as an oxygen-regulated transcription activator and that it activates a unique transcriptional program in response to hypoxia. Many HIF-3α target genes have been identified. While some short HIF-3α variants act as dominant-negative regulators of HIF-1/2α actions, other HIF-3α variants can inhibit HIF-1/2α actions by competing for the common HIF-β. There are also a number of HIF-3α variants yet to be explored. Future studies of these naturally occurring HIF-3α variants will provide new and important insights into HIF biology and may lead to the development of new therapeutic strategies.

  7. Epithelial Barrier Regulation by Hypoxia-Inducible Factor.

    Science.gov (United States)

    Glover, Louise E; Colgan, Sean P

    2017-09-01

    Mucosal tissues represent surfaces that are exposed to the outside world and provide a conduit for internal and external communication. Tissues such as the intestine and the lung are lined by layer(s) of epithelial cells that, when organized in three dimensions, provide a critical barrier to the flux of luminal contents. This selective barrier is provided through the regulated expression of junctional proteins and mucins. Tissue oxygen metabolism is central to the maintenance of homeostasis in the mucosa. In some organs (e.g., the colon), low baseline Po2 determines tissue metabolism and results in basal expression of the transcription factor, hypoxia-inducible factor (HIF), which is enhanced after ischemia/inflammation. Recent studies have indicated that HIF contributes fundamentally to the expression of barrier-related genes and in the regulation of barrier-adaptive responses within the mucosa. Here, we briefly review recent literature on the topic of hypoxia and HIF regulation of barrier in mucosal health and during disease.

  8. Musashi mediates translational repression of the Drosophila hypoxia inducible factor

    Science.gov (United States)

    Bertolin, Agustina P.; Katz, Maximiliano J.; Yano, Masato; Pozzi, Berta; Acevedo, Julieta M.; Blanco-Obregón, Dalmiro; Gándara, Lautaro; Sorianello, Eleonora; Kanda, Hiroshi; Okano, Hideyuki; Srebrow, Anabella; Wappner, Pablo

    2016-01-01

    Adaptation to hypoxia depends on a conserved α/β heterodimeric transcription factor called Hypoxia Inducible Factor (HIF), whose α-subunit is regulated by oxygen through different concurrent mechanisms. In this study, we have identified the RNA binding protein dMusashi, as a negative regulator of the fly HIF homologue Sima. Genetic interaction assays suggested that dMusashi participates of the HIF pathway, and molecular studies carried out in Drosophila cell cultures showed that dMusashi recognizes a Musashi Binding Element in the 3′ UTR of the HIFα transcript, thereby mediating its translational repression in normoxia. In hypoxic conditions dMusashi is downregulated, lifting HIFα repression and contributing to trigger HIF-dependent gene expression. Analysis performed in mouse brains revealed that murine Msi1 protein physically interacts with HIF-1α transcript, suggesting that the regulation of HIF by Msi might be conserved in mammalian systems. Thus, Musashi is a novel regulator of HIF that inhibits responses to hypoxia specifically when oxygen is available. PMID:27141964

  9. Thioredoxin interacting protein inhibits hypoxia-inducible factor transcriptional activity

    Science.gov (United States)

    Farrell, Michael R; Rogers, Lynette K; Liu, Yusen; Welty, Stephen E; Tipple, Trent E

    2010-01-01

    Vascular endothelial growth factor (VEGF) is required for proper lung development and is transcriptionally regulated in alveolar epithelial cells by hypoxia inducible factor (HIF). Previous findings in a newborn mouse model of bronchopulmonary dysplasia (BPD) suggest that thioredoxin interacting protein (Txnip) is a novel regulator of VEGF expression. The present studies were designed to test the hypothesis that Txnip negatively regulates VEGF through effects on HIF-mediated gene expression. To test this hypothesis, we first examined the levels of VEGF and Txnip protein in the lungs of 1 day-old newborn and E19 embryos and detected a significant inverse correlation. To elucidate the mechanisms underlying this relationship, we studied the effects of Txnip overexpression on HIF-mediated transcription using murine lung epithelial (MLE-12) cells. Overexpression of Txnip inhibited HIF-mediated reporter activity in both hypoxia and room air. Suppression of HIF activity by Txnip appeared to be independent of the ability of Txnip to bind to thioredoxin. Thus, our studies support a model in which Txnip is a potentially critical regulator of HIF-mediated gene transcription in the murine lung. Alterations in Txnip expression could alter lung VEGF expression in prematurely born human infants and contribute to the development of BPD. PMID:20692333

  10. Expression of DDX3 is directly modulated by hypoxia inducible factor-1 alpha in breast epithelial cells.

    Directory of Open Access Journals (Sweden)

    Mahendran Botlagunta

    Full Text Available DEAD box protein, DDX3, is aberrantly expressed in breast cancer cells ranging from weakly invasive to aggressive phenotypes and functions as an important regulator of cancer cell growth and survival. Here, we demonstrate that hypoxia inducible factor-1α is a transcriptional activator of DDX3 in breast cancer cells. Within the promoter region of the human DDX3 gene, we identified three putative hypoxia inducible factor-1 responsive elements. By luciferase reporter assays in combination with mutated hypoxia inducible factor-1 responsive elements, we determined that the hypoxia inducible factor-1 responsive element at position -153 relative to the translation start site is essential for transcriptional activation of DDX3 under hypoxic conditions. We also demonstrated that hypoxia inducible factor-1 binds to the DDX3 promoter and that the binding is specific, as revealed by siRNA against hypoxia inducible factor-1 and chromatin immunoprecipitation assays. Thus, the activation of DDX3 expression during hypoxia is due to the direct binding of hypoxia inducible factor-1 to hypoxia responsive elements in the DDX3 promoter. In addition, we observed a significant overlap in the protein expression pattern of hypoxia inducible factor-1α and DDX3 in MDA-MB-231 xenograft tumors. Taken together, our results demonstrate, for the first time, the role of DDX3 as a hypoxia-inducible gene that exhibits enhanced expression through the interaction of hypoxia inducible factor-1 with hypoxia inducible factor-1 responsive elements in its promoter region.

  11. Expression of DDX3 is directly modulated by hypoxia inducible factor-1 alpha in breast epithelial cells.

    Science.gov (United States)

    Botlagunta, Mahendran; Krishnamachary, Balaji; Vesuna, Farhad; Winnard, Paul T; Bol, Guus M; Patel, Arvind H; Raman, Venu

    2011-03-23

    DEAD box protein, DDX3, is aberrantly expressed in breast cancer cells ranging from weakly invasive to aggressive phenotypes and functions as an important regulator of cancer cell growth and survival. Here, we demonstrate that hypoxia inducible factor-1α is a transcriptional activator of DDX3 in breast cancer cells. Within the promoter region of the human DDX3 gene, we identified three putative hypoxia inducible factor-1 responsive elements. By luciferase reporter assays in combination with mutated hypoxia inducible factor-1 responsive elements, we determined that the hypoxia inducible factor-1 responsive element at position -153 relative to the translation start site is essential for transcriptional activation of DDX3 under hypoxic conditions. We also demonstrated that hypoxia inducible factor-1 binds to the DDX3 promoter and that the binding is specific, as revealed by siRNA against hypoxia inducible factor-1 and chromatin immunoprecipitation assays. Thus, the activation of DDX3 expression during hypoxia is due to the direct binding of hypoxia inducible factor-1 to hypoxia responsive elements in the DDX3 promoter. In addition, we observed a significant overlap in the protein expression pattern of hypoxia inducible factor-1α and DDX3 in MDA-MB-231 xenograft tumors. Taken together, our results demonstrate, for the first time, the role of DDX3 as a hypoxia-inducible gene that exhibits enhanced expression through the interaction of hypoxia inducible factor-1 with hypoxia inducible factor-1 responsive elements in its promoter region.

  12. Hypoxia and hypoxia-inducible factors in leukaemias

    Directory of Open Access Journals (Sweden)

    Margaux eDeynoux

    2016-02-01

    Full Text Available Despite huge improvements in the treatment of leukaemia, the percentage of patients suffering relapse still remains significant. Relapse most often results from a small number of leukaemic stem cells (LSCs within the bone marrow, which are able to self-renew and therefore re-establish the full tumour. The marrow microenvironment contributes considerably in supporting the protection and development of leukaemic cells. LSCs share specific niches with normal haematopoietic stem cells with the niche itself being composed of a variety of cell types including mesenchymal stem/stromal cells, bone cells, immune cells, neuronal cells and vascular cells. A hallmark of the haematopoietic niche is low oxygen partial pressure, indeed this hypoxia is necessary for the long-term maintenance of HSCs. Hypoxia is a strong signal, principally maintained by members of the hypoxia-inducible factor family. In solid tumours, it has been well-established that hypoxia triggers intrinsic metabolic changes and microenvironmental modifications, such as the stimulation of angiogenesis, through activation of HIFs. As leukaemia is not considered a solid tumour, the role of oxygen in the disease was presumed to be inconsequential and remained long overlooked. This view has now been revised since hypoxia has been shown to influence leukaemic cell proliferation, differentiation and resistance to chemotherapy. However, the role of HIF proteins remains controversial with HIFs being considered as either oncogenes or tumour suppressor genes, depending on the study and model. The purpose of this review is to highlight our knowledge of hypoxia and HIFs in leukaemic development and therapeutic resistance, and to discuss the recent hypoxia-based strategies proposed to eradicate leukaemias.

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

    Directory of Open Access Journals (Sweden)

    Pei Wang

    2013-09-01

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

  14. Hypoxia-induced cell death and changes in hypoxia-inducible factor-1 activity in PC12 cells upon exposure to nerve growth factor.

    Science.gov (United States)

    Charlier, Nico; Leclere, Norbert; Felderhoff, Ursula; Heldt, Julia; Kietzmann, Thomas; Obladen, Michael; Gross, Johann

    2002-07-15

    The transcription factor hypoxia-inducible factor-1 (HIF-1) strongly contributes to the expression of adaptive genes under hypoxic conditions. In addition, HIF-1 has been implicated in the regulation of delayed neuronal cell death. Suspension-grown and adherent PC12 cells treated with NGF were used as an experimental model for studying the relationship between hypoxia-induced cell death and activation of HIF-1. Cell damage was assessed by flow cytometry of double-stained (Annexin V and propidiumiodide) cells, and by analysis of the overall death parameters LDH and mitochondrial dehydrogenase. In parallel, cells were transfected with a control and a three-hypoxia-responsive-elements (HRE)-containing vector and HIF-1-driven luciferase activity was determined. Exposure of NGF-treated PC12 cells to hypoxia resulted in a higher cell death rate when compared to untreated controls. PC12 cells exposed for 2 days to NGF exhibited a decrease of HIF-1 activity up to a factor of ten. This decrease may contribute to the enhanced hypoxia-induced cell death via reduced expression of HIF-1alpha-regulated genes responsible for adaptation to hypoxia, like those for glucose transport proteins and enzymes of the glycolytic chain. The decrease in HIF-1 activity and the increase in hypoxia sensitivity may suggest that NGF act as an hierarchically organized signaling molecule.

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

    DEFF Research Database (Denmark)

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

    2008-01-01

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

  16. Hypoxia-inducible factors - regulation, role and comparative aspects in tumourigenesis

    DEFF Research Database (Denmark)

    Hansen, A E; Kristensen, A T; Law, I;

    2011-01-01

    Hypoxia-inducible factors (HIFs) play a key role in the cellular response experienced in hypoxic tumours, mediating adaptive responses that allow hypoxic cells to survive in the hostile environment. Identification and understanding of tumour hypoxia and the influence on cellular processes carries...

  17. Role of chronic hypoxia and hypoxia inducible factor in kidney disease

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Cells are endowed with a defensive mechanism against hypoxia,namely hypoxia-inducible factor (HIF) and hypoxia-responsive element (HRE).Under hypoxic conditions,activation of HIF leads to expression of a variety of adaptive genes with HRE in a coordinated manner.

  18. Hypoxia-Inducible Factor 2α Mutation-Related Paragangliomas Classify as Discrete Pseudohypoxic Subcluster

    NARCIS (Netherlands)

    S.M.J. Fliedner (Stephanie); U. Shankavaram (Uma); Marzouca, G. (Geena); Elkahloun, A. (Abdel); Jochmanova, I. (Ivana); Daerr, R. (Roland); Linehan, W.M. (W. Marston); H.J. Timmers (Henri); A.S. Tischler (Arthur); K. Papaspyrou (Konstantinos); Brieger, J. (Jürgen); R.R. de Krijger (Ronald); Breza, J. (Jan); Eisenhofer, G. (Graeme); Zhuang, Z. (Zhengping); Lehnert, H. (Hendrik); K. Pacak (Karel)

    2016-01-01

    textabstractRecently, activating mutations of the hypoxia-inducible factor 2α gene (HIF2A/EPAS1) have been recognized to predispose to multiple paragangliomas (PGLs) and duodenal somatostatinomas associated with polycythemia, and ocular abnormalities. Previously, mutations in the SDHA/B/C/D, SDHAF2,

  19. Hypoxia-Inducible Factor 2alpha Mutation-Related Paragangliomas Classify as Discrete Pseudohypoxic Subcluster

    NARCIS (Netherlands)

    Fliedner, S.M.; Shankavaram, U.; Marzouca, G.; Elkahloun, A.; Jochmanova, I.; Daerr, R.; Linehan, W.M.; Timmers, H.J.; Tischler, A.S.; Papaspyrou, K.; Brieger, J.; Krijger, R. de; Breza, J.; Eisenhofer, G.; Zhuang, Z.; Lehnert, H.; Pacak, K.

    2016-01-01

    Recently, activating mutations of the hypoxia-inducible factor 2alpha gene (HIF2A/EPAS1) have been recognized to predispose to multiple paragangliomas (PGLs) and duodenal somatostatinomas associated with polycythemia, and ocular abnormalities. Previously, mutations in the SDHA/B/C/D, SDHAF2, VHL,

  20. Hypoxia-inducible factor prolyl 4-hydroxylases regulating erythropoiesis, and hypoxia-inducible lysyl oxidase regulating skeletal muscle development during embryogenesis

    OpenAIRE

    Laitala, A. (Anu)

    2014-01-01

    Abstract Erythropoiesis is the process of red blood cell production. The main regulator is the erythropoietin (EPO) hormone, which is strongly upregulated in low oxygen concentration (hypoxia) in cells via the hypoxia-inducible transcription factor HIF. The stability of HIF is regulated in an oxygen-dependent manner by three HIF prolyl 4-hydroxylases, all of which are known to participate in the regulation of erythropoiesis. A role in erythropoiesis of a fourth prolyl 4-hydroxylase, P4H-TM...

  1. Puerarin decreases hypoxia inducible factor-1 alpha in the hippocampus of vascular dementia rats

    Institute of Scientific and Technical Information of China (English)

    Haiqin Wu; Huqing Wang; Bei Zhang; Guilian Zhang; Ru Zhang; Lingfeng Zhang

    2012-01-01

    In this study, a rat vascular dementia model was established by permanent bilateral common carotid arterial occlusion. Rats were intraperitoneally injected with puerarin 3 days before modeling, for 45 successive days. Results demonstrated that in treated animals hippocampal structures were clear, nerve cells arranged neatly, and cytoplasm was rich in Nissl bodies. The number of cells positive for hypoxia inducible factor-1 alpha, erythropoietin and endothelial nitric oxide synthase was reduced; and the learning and memory abilities of rats were significantly improved. Our experimental findings indicate that puerarin can significantly improve learning and memory in a vascular dementia model, and that the underlying mechanism may be associated with the regulation of the expression of hypoxia inducible factor-1 alpha.

  2. A Synthetic Manassantin A Derivative Inhibits Hypoxia-Inducible Factor 1 and Tumor Growth

    OpenAIRE

    Liwei Lang; Xiaoyu Liu; Yan Li; Qing Zhou; Ping Xie; Chunhong Yan; Xiaoguang Chen

    2014-01-01

    The dineolignan manassantin A from Saururaceae was recently identified as a hypoxia-inducible factor 1 (HIF-1) inhibitor, but its in-vivo anti-tumor effect has not been explored. We synthesized a series of manassantin A derivatives, and found that replacing the central tetrahydrofuran moiety with a cyclopentane ring yielded a compound (LXY6006) with increased HIF-1-inhibitory activity yet decreased stereochemically complexity amenable to a simplified synthesis scheme. LXY6006 inhibited HIF-1α...

  3. Synthesis and Biological Evaluation of Manassantin Analogues for Hypoxia-Inducible Factor 1α Inhibition

    OpenAIRE

    Kwon, Do-Yeon; Lee, Hye Eun; Weitzel, Douglas H.; PARK, KYUNGHYE; Lee, Sun Hee; Lee, Chen-Ting; Stephenson, Tesia N.; Park, Hyeri; Fitzgerald, Michael C.; Chi, Jen-Tsan; Mook, Robert A.; Dewhirst, Mark W.; Lee, You Mie; Hong, Jiyong

    2015-01-01

    To cope with hypoxia, tumor cells have developed a number of adaptive mechanisms mediated by hypoxia-inducible factor 1 (HIF-1) to promote angiogenesis and cell survival. Due to significant roles of HIF-1 in the initiation, progression, metastasis, and resistance to treatment of most solid tumors, a considerable amount of effort has been made to identify HIF-1 inhibitors for treatment of cancer. Isolated from Saururus cernuus, manassantins A (1) and B (2) are potent inhibitors of HIF-1 activi...

  4. Saururus cernuus Lignans - Potent Small Molecule Inhibitors of Hypoxia-Inducible Factor-1

    OpenAIRE

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

    2005-01-01

    Hypoxia-inducible factor-1 (HIF-1) represents an important tumor-selective therapeutic target for solid tumors. In search of novel small molecule HIF-1 inhibitors, 5400 natural product-rich extracts from plants, marine organisms, and microbes were examined for HIF-1 inhibitory activities using a cell-based reporter assay. Bioassay-guided fractionation and isolation, followed by structure elucidation, yielded three potent natural product-derived HIF-1 inhibitors and two structurally related in...

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

    Science.gov (United States)

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

    2005-08-05

    Hypoxia-inducible factor-1 (HIF-1) represents an important tumor-selective therapeutic target for solid tumors. In search of novel small molecule HIF-1 inhibitors, 5400 natural product-rich extracts from plants, marine organisms, and microbes were examined for HIF-1 inhibitory activities using a cell-based reporter assay. Bioassay-guided fractionation and isolation, followed by structure elucidation, yielded three potent natural product-derived HIF-1 inhibitors and two structurally related inactive compounds. In a T47D cell-based reporter assay, manassantin B1, manassantin A, and 4-O-methylsaucerneol inhibited hypoxia-induced HIF-1 activation with IC50 values of 3, 3, and 20 nM, respectively. All three compounds are relatively hypoxia-specific inhibitors of HIF-1 activation, in comparison to other stimuli. The hypoxic induction of HIF-1 target genes CDKN1A, VEGF, and GLUT-1 were also inhibited. These compounds inhibit HIF-1 by blocking hypoxia-induced nuclear HIF-1alpha protein accumulation without affecting HIF-1alpha mRNA levels. In addition, preliminary structure-activity studies suggest specific structural requirements for this class of HIF-1 inhibitors.

  6. Saururus cernuus Lignans - Potent Small Molecule Inhibitors of Hypoxia-Inducible Factor-1

    Science.gov (United States)

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

    2010-01-01

    Hypoxia-inducible factor-1 (HIF-1) represents an important tumor-selective therapeutic target for solid tumors. In search of novel small molecule HIF-1 inhibitors, 5400 natural product-rich extracts from plants, marine organisms, and microbes were examined for HIF-1 inhibitory activities using a cell-based reporter assay. Bioassay-guided fractionation and isolation, followed by structure elucidation, yielded three potent natural product-derived HIF-1 inhibitors and two structurally related inactive compounds. In a T47D cell-based reporter assay, manassantin B1, manassantin A, and 4-O-methylsaucerneol inhibited hypoxia-induced HIF-1 activation with IC50 values of 3, 3, and 20 nM, respectively. All three compounds are relatively hypoxia-specific inhibitors of HIF-1 activation, in comparison to other stimuli. The hypoxic induction of HIF-1 target genes CDKN1A, VEGF and GLUT-1 were also inhibited. These compounds inhibit HIF-1 by blocking hypoxia-induced nuclear HIF-1α protein accumulation without affecting HIF-1α mRNA levels. In addition, preliminary structure-activity studies suggest specific structural requirements for this class of HIF-1 inhibitors. PMID:15967416

  7. Hypoxia-inducible factor-1 alpha regulates the role of vascular endothelial growth factor on pulmonary arteries of rats with hypoxia-induced pulmonary hypertension

    Institute of Scientific and Technical Information of China (English)

    李启芳; 戴爱国

    2004-01-01

    Background Hypoxia-inducible factor-1α (HIF-1α) is one of the pivotal mediators in the response of lungs to decreased oxygen availability, and increasingly has been implicated in the pathogenesis of pulmonary hypertension. Vascular endothelial growth factor (VEGF), a downstream target gene of HIF-1α, plays an important role in the pathogenesis of hypoxic pulmonary hypertension and hypoxic pulmonary artery remodelling. In this study, we investigated the dynamic expression of HIF-1α and VEGF in pulmonary artery of rats with hypoxia-induced pulmonary hypertension. Methods Forty male Wistar rats were exposed to hypoxia for 0, 3, 7, 14 or 21 days. Mean pulmonary arterial pressure (mPAP), vessel morphometry and right ventricle hypertrophy index (RVHI) were estimated. Lungs were inflated and fixed for in situ hybridisation and immunohistochemistry. Results mPAP values were significantly higher than the control values after 7days of hypoxia [(18.4±0.4) mmHg, P<0.05]. RVHI developed significantly after 14 days of hypoxia. Expression of HIF-1α protein increased in pulmonary arterial tunica intima of all hypoxic rats. In pulmonary arterial tunica media, HIF-1α protein was markedly increased by day 3 (0.20±0.02, P<0.05), reached the peak by day 7, then declined after day 14 of hypoxia. HIF-1α mRNA increased significantly after day 14 of hypoxia (0.20±0.02, P<0.05). VEGF protein began to increase markedly after day 7 of hypoxia, reaching its peak around day 14 of hypoxia (0.15±0.02, P<0.05). VEGF mRNA began to increase after day 7 of hypoxia, then remained more or less stable from day 7 onwards. VEGF mRNA is located mainly in tunica intima and tunica media, whereas VEGF protein is located predominantly in tunica intima. Linear analysis showed that HIF-1α mRNA, VEGF and mPAP were correlated with hypoxic pulmonary artery remodelling. HIF-1α mRNA was positively correlated with VEGF mRNA and protein (P<0.01). Conclusion HIF-1α and VEGF are both involved in the

  8. Expression and role of factor inhibiting hypoxia-inducible factor-1 in pulmonary arteries of rat with hypoxia-induced hypertension

    Institute of Scientific and Technical Information of China (English)

    Daiyan Fu; Aiguo Dai; Ruicheng Hu; Yunrong Chen; Liming Zhu

    2008-01-01

    Hypoxia-inducible factor-11α subunit (HIF-1α) plays a pivotal role during the development of hypoxia-induced pulmonary hypertension (HPH) by transactivating it's target genes. As an oxygen-sensitive attenuator, factor inhibiting HIF-1 (FIH)hydroxylates a conserved asparagine residue within the C-terminal transactivation domain of HIF-1α under normoxia and moderate hypoxia. FIH protein is downregulated in response to hypoxia, but its dynamic expression and role during the development of HPH remains unclear. In this study,an HPH rat model was established. The mean pulmonary arterial pressure increased significantly after 7 d of hypoxia.The pulmonary artery remodeling index became evident after 7 d of hypoxia, while the right ventricular hypertrophy index became significant after 14 d of hypoxia. The messenger RNA (mRNA) and protein expression of HIF-1α and vascular endothelial growth factor (VEGF), a well-characterized target gene of HIF-1α, were markedly upregulated after exposure to hypoxia in pulmonary arteries. FIH protein in lung tissues declined after 7 d of hypoxia and continued to decline through the duration of hypoxia. FIH mRNA had few changes after exposure to hypoxia compared with after exposure to normoxia.In hypoxic rats, FIH protein showed significant negative correlation with VEGF mRNA and VEGF protein. FIH protein was negatively correlated with mean pulmonary arterial pressure, pulmonary artery remodeling index and right ventricular hypertrophy index. Taken together, our results suggest that, in the pulmonary arteries of rat exposed to moderate hypoxia, a time-dependent decrease in FIH protein may contribute to the development of rat HPH by enhancing the transactivation of HIF-1α target genes such as VEGF.

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

    African Journals Online (AJOL)

    under prolonged high glucose, the low expression of HIF-1α led to low expressions of Glut-1, HXK-2 and enolase. ... role in the regulation of physiological and .... significantly altered glucose and lipid metabolism .... growth factor and its receptors in insulin-resistant and ... density, and activation of cell survival signaling. Eur J.

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

    Directory of Open Access Journals (Sweden)

    Lv Y

    2015-07-01

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

  11. Hypoxia-inducible factor and vascular endothelial growth factor in the neuroretina and retinal blood vessels after retinal ischemia

    DEFF Research Database (Denmark)

    Håkansson, Gisela; Gesslein, Bodil; Gustafsson, Lotta

    2010-01-01

    Retinal ischemia arises from circulatory failure. As the retinal blood vessels are key organs in circulatory failure, our aim was to study the retinal vasculature separately from the neuroretina to elucidate the role of hypoxia-inducible factor (HIF) 1α and 1β and vascular endothelial growth factor...

  12. Hypoxia inducible factor-1αaccumulation in steatotic liver preservation:Role of nitric oxide

    Institute of Scientific and Technical Information of China (English)

    Mohamed; Amine; Zaouali; Ismail; Ben; Mosbah; Eleonora; Boncompagni; Hassen; Ben; Abdennebi; Maria; Teresa; Mitjavila; Ramon; Bartrons; Isabel; Freitas; Antoni; Rimola; Joan; Roselló-Catafau

    2010-01-01

    AIM:To examine the relevance of hypoxia inducible factor(HIF-1)and nitric oxide(NO)on the preservation of fatty liver against cold ischemia-reperfusion injury(IRI). METHODS:We used an isolated perfused rat liver model and we evaluated HIF-1αin steatotic and non-steatotic livers preserved for 24 h at 4℃in University of Wisconsin and IGL-1 solutions,and then subjected to 2 h of normothermic reperfusion.After normoxic reperfusion,liver enzymes,bile production,bromosulfophthalein clearance,as well as HIF-1αand ...

  13. Isorhamnetin Inhibits Reactive Oxygen Species-Dependent Hypoxia Inducible Factor (HIF)-1α Accumulation.

    Science.gov (United States)

    Seo, Suho; Seo, Kyuhwa; Ki, Sung Hwan; Shin, Sang Mi

    2016-01-01

    Isorhamnetin is a flavonoid metabolite of quercetin and isolated from water dropwort (Oenanthe javanica, Umbelliferae). It has been reported that isorhamnetin exerts beneficial effects including antioxidant, anti-inflammatory, and anti-proliferative activities. The present study investigated whether the antioxidant activity of isorhamnetin is correlated with its anti-cancer effects on colorectal cancer cells. Isorhamnetin significantly repressed cobalt chloride (CoCl2)- or hypoxia-induced hypoxia inducible factor-1α (HIF-1α) accumulation in HCT116 and HT29 cells. When compared with quercetin, isorhamnetin showed potent inhibition of HIF-1α. Moreover, it inhibited CoCl2-induced activity of hypoxia response element reporter gene and HIF-1α-dependent transcription of genes such as glucose transporter 1, lactate dehydrogenase A, carbonic anhydrase-IX, and pyruvate dehydrogenase kinase 1. Isorhamnetin also blocked hydrogen peroxide (H2O2)-induced HIF-1α accumulation. The antioxidant effects of isorhamnetin were confirmed by observation of CoCl2- or H2O2-induced reactive oxygen species (ROS) production. Consistently, overexpressed HIF-1α was decreased by isorhamnetin or N-acetyl-L-cysteine in HEK293 cells. In vitro migration and invasion assay further confirmed the inhibitory effects of isorhamnetin on cancer cells. Collectively, these results demonstrate that isorhamnetin inhibits ROS-mediated HIF-1α accumulation, which contributes to its anti-metastatic efficacy.

  14. Synthesis and Biological Evaluation of Manassantin Analogues for Hypoxia-Inducible Factor 1α Inhibition.

    Science.gov (United States)

    Kwon, Do-Yeon; Lee, Hye Eun; Weitzel, Douglas H; Park, Kyunghye; Lee, Sun Hee; Lee, Chen-Ting; Stephenson, Tesia N; Park, Hyeri; Fitzgerald, Michael C; Chi, Jen-Tsan; Mook, Robert A; Dewhirst, Mark W; Lee, You Mie; Hong, Jiyong

    2015-10-08

    To cope with hypoxia, tumor cells have developed a number of adaptive mechanisms mediated by hypoxia-inducible factor 1 (HIF-1) to promote angiogenesis and cell survival. Due to significant roles of HIF-1 in the initiation, progression, metastasis, and resistance to treatment of most solid tumors, a considerable amount of effort has been made to identify HIF-1 inhibitors for treatment of cancer. Isolated from Saururus cernuus, manassantins A (1) and B (2) are potent inhibitors of HIF-1 activity. To define the structural requirements of manassantins for HIF-1 inhibition, we prepared and evaluated a series of manassantin analogues. Our SAR studies examined key regions of manassantin's structure in order to understand the impact of these regions on biological activity and to define modifications that can lead to improved performance and drug-like properties. Our efforts identified several manassantin analogues with reduced structural complexity as potential lead compounds for further development. Analogues MA04, MA07, and MA11 down-regulated hypoxia-induced expression of the HIF-1α protein and reduced the levels of HIF-1 target genes, including cyclin-dependent kinase 6 (Cdk6) and vascular endothelial growth factor (VEGF). These findings provide an important framework to design potent and selective HIF-1α inhibitors, which is necessary to aid translation of manassantin-derived natural products to the clinic as novel therapeutics for cancers.

  15. Hypoxia-inducible factor 1 alpha and vascular endothelial growth factor overexpression in ischemic colitis

    Institute of Scientific and Technical Information of China (English)

    Tomoyuki Okuda; Takeshi Azuma; Masahiro Ohtani; Ryuho Masaki; Yoshiyuki Ito; Yukinao Yamazaki; Shigeji Ito; Masaru Kuriyama

    2005-01-01

    AIM: To examine the etiology and pathophysiology in human ischemic colitis from the viewpoint of ischemic favors such as hypoxia-inducible factor 1 alpha (HIF-1alpha and vascular endothelial growth factor (VEGF).METHODS: Thirteen patients with ischemic colitis and 21 normal controls underwent colonoscopy. The follow-up colonoscopy was performed in 8 patients at 7 to 10 d after theoccurrence of ischemic colitis. Biopsy samples were subjected to real-time RT-PCR and immunohistochemistry to detect the expression of HIF-1 alpha and VEGF.RESULTS: HIF-1 alpha and VEGF expression were found in the normal colon tissues by RT-PCR and immunohistochemistry.HIF-1 alpha and VEGF were overexpressed in the lesions of ischemic colitis. Overexpressed HIF-1 alpha and VEGF RNA quickly decreased to the normal level in the scar regions at 7 to 10 d after the occurrence of ischemic colitis.CONCLUSION: Constant expression of HIF-1 alpha and VEGF in normal human colon tissue suggested that HIF-1alpha and VEGF play an important role in maintaining tissue integrity. We confirmed the ischemic crisis in ischemic colitis at the molecular level, demonstrating overexpression of HIF-1 alpha and VEGF in ischemic lesions. These ischemic factors may play an important role in the pathophysiology of ischemic colitis.

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

    Directory of Open Access Journals (Sweden)

    Shunsuke Ohnishi

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

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

    NARCIS (Netherlands)

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

    2005-01-01

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

  18. Expression of hypoxia-inducible factor 1α in human normal, benign, and malignant prostate tissue

    Institute of Scientific and Technical Information of China (English)

    都镇先; 藤山千里; 陈永昕; 真崎善二郎

    2003-01-01

    Objective To investigate hypoxia-inducible factor 1α (HIF-1α) protein expression in normal prostates (NP), benign prostatic glandular hyperplasia (BPH), and prostate adenocarcinoma (Pca).Methods HIF-1α protein expression was determined by immunohistochemistry in formalin-fixed and paraffin-embedded specimens obtained from 13 cases of NP, 28 cases of BPH, and 34 cases of Pca. In cases of Pca, the relationship between HIF-1α protein expression and certain clinicopathological factors, such as clinicopathologic stage and Gleason score, was evaluated.Results NP manifested no immunoreactivity, whereas Pca and BPH showed significantly increased HIF-1α protein expression. A significantly higher expression was observed in Pca specimens compared with BPH samples. In Pca, no significant relationship between HIF-1α protein expression and clinicopathological factors was found.Conclusion Our findings of increased HIF-1α protein expression in BPH and Pca specimens suggests the potential role of this protein in BPH and Pca.

  19. Therapeutic treatment with a novel hypoxia-inducible factor hydroxylase inhibitor (TRC160334 ameliorates murine colitis

    Directory of Open Access Journals (Sweden)

    Gupta R

    2014-01-01

    Full Text Available Ram Gupta,1 Anita R Chaudhary,2 Binita N Shah,1 Avinash V Jadhav,3 Shitalkumar P Zambad,1 Ramesh Chandra Gupta,4 Shailesh Deshpande,4 Vijay Chauthaiwale,4 Chaitanya Dutt4 1Department of Pharmacology, 2Cellular and Molecular Biology, 3Preclinical Safety Evaluation, 4Discovery, Torrent Research Centre, Torrent Pharmaceuticals Ltd, Gandhinagar, Gujarat, India Background and aim: Mucosal healing in inflammatory bowel disease (IBD can be achieved by improvement of intestinal barrier protection. Activation of hypoxia-inducible factor (HIF has been identified as a critical factor for barrier protection during mucosal insult and is linked with improvement in symptoms of colitis. Although prophylactic efficacy of HIF hydroxylase inhibitors in murine colitis have been established, its therapeutic efficacy in clinically relevant therapeutic settings have not been established. In the present study we aim to establish therapeutic efficacy of TRC160334, a novel HIF hydroxylase inhibitor, in animal models of colitis. Methods: The efficacy of TRC160334 was evaluated in two different mouse models of colitis by oral route. A prophylactic efficacy study was performed in a 2,4,6-trinitrobenzene sulfonic acid-induced mouse model of colitis representing human Crohn's disease pathology. Additionally, a therapeutic efficacy study was performed in a dextran sulfate sodium-induced mouse model of colitis, a model simulating human ulcerative colitis. Results: TRC160334 treatment resulted in significant improvement in disease end points in both models of colitis. TRC160334 treatment resulted into cytoprotective heatshock protein 70 induction in inflamed colon. TRC160334 successfully attenuated the rate of fall in body weight, disease activity index, and macroscopic and microscopic scores of colonic damage leading to overall improvement in study outcome. Conclusion: Our findings are the first to demonstrate that therapeutic intervention with a HIF hydroxylase inhibitor

  20. A synthetic manassantin a derivative inhibits hypoxia-inducible factor 1 and tumor growth.

    Science.gov (United States)

    Lang, Liwei; Liu, Xiaoyu; Li, Yan; Zhou, Qing; Xie, Ping; Yan, Chunhong; Chen, Xiaoguang

    2014-01-01

    The dineolignan manassantin A from Saururaceae was recently identified as a hypoxia-inducible factor 1 (HIF-1) inhibitor, but its in-vivo anti-tumor effect has not been explored. We synthesized a series of manassantin A derivatives, and found that replacing the central tetrahydrofuran moiety with a cyclopentane ring yielded a compound (LXY6006) with increased HIF-1-inhibitory activity yet decreased stereochemically complexity amenable to a simplified synthesis scheme. LXY6006 inhibited HIF-1α nuclear accumulation induced by hypoxia, and inhibited cancer cell growth as a consequence of G2/M arrest. Oral administration of LXY6006 significantly inhibited growth of breast, lung, and pancreatic tumors implanted in nude mice. These results indicate that LXY6006 represents a novel class of agents targeting a broad range of human cancers.

  1. A synthetic manassantin a derivative inhibits hypoxia-inducible factor 1 and tumor growth.

    Directory of Open Access Journals (Sweden)

    Liwei Lang

    Full Text Available The dineolignan manassantin A from Saururaceae was recently identified as a hypoxia-inducible factor 1 (HIF-1 inhibitor, but its in-vivo anti-tumor effect has not been explored. We synthesized a series of manassantin A derivatives, and found that replacing the central tetrahydrofuran moiety with a cyclopentane ring yielded a compound (LXY6006 with increased HIF-1-inhibitory activity yet decreased stereochemically complexity amenable to a simplified synthesis scheme. LXY6006 inhibited HIF-1α nuclear accumulation induced by hypoxia, and inhibited cancer cell growth as a consequence of G2/M arrest. Oral administration of LXY6006 significantly inhibited growth of breast, lung, and pancreatic tumors implanted in nude mice. These results indicate that LXY6006 represents a novel class of agents targeting a broad range of human cancers.

  2. Hypoxia inducible factor 1α promotes survival of mesenchymal stem cells under hypoxia

    Science.gov (United States)

    Lv, Bingke; Li, Feng; Fang, Jie; Xu, Limin; Sun, Chengmei; Han, Jianbang; Hua, Tian; Zhang, Zhongfei; Feng, Zhiming; Jiang, Xiaodan

    2017-01-01

    Mesenchymal stem cells (MSCs) are ideal materials for cell therapy. Research has indicated that hypoxia benefits MSC survival, but little is known about the underlying mechanism. This study aims to uncover potential mechanisms involving hypoxia inducible factor 1α (HIF1A) to explain the promoted MSC survival under hypoxia. MSCs were obtained from Sprague-Dawley rats and cultured under normoxia or hypoxia condition. The overexpression vector or small interfering RNA of Hif1a gene was transfected to MSCs, after which cell viability, apoptosis and expression of HIF1A were analyzed by MTT assay, flow cytometry, qRT-PCR and Western blot. Factors in p53 pathway were detected to reveal the related mechanisms. Results showed that hypoxia elevated MSCs viability and up-regulated HIF1A (P cell CLL/lymphoma 2 (BCL2) expression had the opposite pattern (P cell therapy.

  3. Endothelium-derived hyperpolarizing factor contributes to hypoxia-induced skeletal muscle vasodilation in humans.

    Science.gov (United States)

    Spilk, Samson; Herr, Michael D; Sinoway, Lawrence I; Leuenberger, Urs A

    2013-12-01

    Systemic hypoxia causes skeletal muscle vasodilation, thereby preserving O2 delivery to active tissues. Nitric oxide (NO), adenosine, and prostaglandins contribute to this vasodilation, but other factors may also play a role. We tested the hypothesis that regional inhibition of endothelium-derived hyperpolarizing factor with the cytochrome P-450 2C9 antagonist fluconazole, alone or combined with the NO synthase antagonist N(G)-monomethyl-L-arginine (L-NMMA), attenuates hypoxia-induced vasodilation. We compared forearm blood flow (FBF) and skin blood flow before and during brachial artery infusion of fluconazole (0.3 mg/min; trial 1) or fluconazole + L-NMMA (50 mg over 10 min; trial 2) and during systemic hypoxia (10 min, arterial Po2 ~37 mmHg) in infused (experimental) and control forearms of 12 healthy humans. During normoxia, fluconazole and fluconazole + L-NMMA reduced (P vasodilation and could be particularly relevant when other vasodilator systems are impaired.

  4. No amplifications of hypoxia-inducible factor-1α gene in invasive breast cancer: A tissue microarray study

    NARCIS (Netherlands)

    Vleugel, M.M.; Bos, R.; Buerger, Horst; Groep, P. van der; Saramäki, O.R.; Visakorpi, T.; Wall, E. van der; Diest, P.J. van

    2004-01-01

    OBJECTIVE: Hypoxia Inducible Factor-1 (HIF-1) is an important transcription factor that stimulates tumour growth and metastases via several pathways, including angiogenesis and altered metabolism. Activation of HIF-1 depends on the levels of its α-subunit, which increase during hypoxia. Recent

  5. Retinal hypoxia induces vascular endothelial growth factor through induction of estrogen-related receptor γ

    Energy Technology Data Exchange (ETDEWEB)

    Do, Ji Yeon; Choi, Young Keun [Leading-edge Research Center for Drug Discovery and Development for Diabetes and Metabolic Disease, Kyungpook National University School of Medicine, Kyungpook National University, Daegu (Korea, Republic of); Kook, Hyun [Department of Pharmacology, Chonnam National University Medical School, Gwangju (Korea, Republic of); Suk, Kyoungho [Department of Pharmacology, Brain Science & Engineering Institute, Kyungpook National University School of Medicine, Daegu (Korea, Republic of); Lee, In-Kyu [Leading-edge Research Center for Drug Discovery and Development for Diabetes and Metabolic Disease, Kyungpook National University School of Medicine, Kyungpook National University, Daegu (Korea, Republic of); Division of Endocrinology and Metabolism, Department of Internal Medicine, Research Institute of Aging and Metabolism, Kyungpook National University School of Medicine, Daegu (Korea, Republic of); Park, Dong Ho, E-mail: sarasate2222@gmail.com [Department of Ophthalmology, Kyungpook National University School of Medicine, Daegu (Korea, Republic of)

    2015-05-01

    Ischemic retinopathies causing overexpression of pro-angiogenic factors, including vascular endothelial growth factor (VEGF), are the most common cause of blindness. Thus, understanding the pathophysiology of targetable pathways that regulate retinal VEGF is of great interest. A conserved binding site for estrogen-related receptor γ (ERRγ) has been identified in the promoter of the Vegfa gene. ERRγ is a constitutively active orphan nuclear receptor and its expression is increased by hypoxic stimuli in metabolically active tissues. This study evaluated the role of ERRγ in the ischemic retina and the anti-VEGF potential of GSK5182, a selective inverse agonist of ERRγ. In an oxygen-induced retinopathy (OIR) mouse model, immunohistochemistry showed significantly increased ERRγ expression in the ganglion cell layer at postnatal day (P) 17. In a ganglion cell line (RGC-5), mRNA and protein levels of ERRγ were increased by desferrioxamine treatment and hypoxic conditions (1% O{sub 2}). Transient transfection of RGC-5 cells revealed that ERRγ regulated Vegfa expression and this was inhibited by GSK5182. Intravitreal injection of GSK5182 into the OIR model at P14 inhibited retinal Vegfa mRNA expression at P17. GSK5182 suppresses hypoxia-induced VEGF expression via ERRγ; therefore, ERRγ could be a treatment target for ischemic retinopathies. - Highlights: • OIR mice exhibited increased ERRγ expression in the ganglion cell layer. • Hypoxia-induced ERRγ expression was observed in retinal ganglion cells. • ERRγ overexpression increased VEGFA expression in retinal ganglion cells. • An ERRγ inverse agonist suppressed VEGFA expression in retinal ganglion cells. • Intravitreal injection of an ERRγ inverse agonist suppressed VEGFA in OIR mice.

  6. EXPRESSION OF HYPOXIA INDUCIBLE FACTOR-1α AND ITS REGULATORY ROLE IN DEVELOPING VERTEBRAE

    Institute of Scientific and Technical Information of China (English)

    ZHU Xun-bing; DENG Lian-fu; XIAO Yu-zhou

    2009-01-01

    Objective To explore the expression pattern and possible role of hypoxia inducible factor-1α(HIF-1α) in fetal vertebrae development of mouse.Methods The developmental stages of mice fetal vertebrae were observed from embryonic days 13.5 to 18.5 (E13.5 to E18.5) by stereoscopic and light microscopes respectively, and the expressions of HIF-1α at various times were also detected at levels of mRNA and protein by using methods of RT-PCR and Western blotting. Distribution of HIF-1α in the vertebrae was examined by immunohistochemical assay. Vascular endothelia growth factor (VEGF) mRNA and other chondro-osteoblast marker genes as type Ⅱ collagen a1 (Coll2a1) and osteocalcin (OCN) were detected by RT-PCR too.Results The cartilaginous spine column began to form at E13.5, followed by the arising of the primary ossification center in vertebrae at E15.5, then the osteogenesis expanded and extended to both sides of the vertebrae. HIF-1α mRNA began to express at E13.5, and showed significantly higher level at E14.5 (P<0.05), then declined to a low level. VEGF mRNA expressed coincidently with HIF-1α. While HIF-1α protein expression was observed at E14.5 and lasted at low level till to birth. The expression pattern of Coll2a1 and OCN elucidated the cell evolution from chondrocyte to osteoblast.Conclusion The developmental pattern of vertebrae appears to be an endochondral osteogenesis process. Existed hypoxia microenviroment in the vertebrae may increase HIF-1α mRNA and protein contents thus activate VEGF expression, as may be related to the activation of other downstream genes of hypoxia inducible factor-1α and initiate the cascade of endochondral osteogenesis.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-08-15

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

  8. Copper is required for cobalt-induced transcriptional activity of hypoxia-inducible factor-1.

    Science.gov (United States)

    Qiu, Liying; Ding, Xueqin; Zhang, Zhen; Kang, Y James

    2012-08-01

    Cobalt inhibits prolyl hydroxylases, leading to the accumulation of hypoxia-inducible factor-1α (HIF-1α) and a concomitant increase in the transcriptional activity of HIF-1. Therefore, cobalt has been under development as a drug for activating HIF-1 under some disease conditions. However, it has been shown that ischemic conditions resulted in the loss of copper, and the activation of HIF-1 would not occur unless copper was supplemented. The present study was undertaken to test the hypothesis that copper is also required for the cobalt activation of HIF-1 transcriptional activity. Human umbilical vein endothelial cells subjected to treatment with cobalt chloride (CoCl(2)) at concentrations above 25 μM for 2 h resulted in an accumulation of HIF-1α, which was determined by Western blot analysis, and an increase in the expression of vascular endothelial growth factor (VEGF), which was determined by real-time reverse transcription-polymerase chain reaction analysis for mRNA levels and enzyme-linked immunosorbent assay analysis for protein levels. The copper chelator tetraethylenepentamine at 25 μM did not significantly affect the accumulation of HIF-1α but blocked increases in VEGF mRNA and protein levels, an effect that could be reversed by the addition of 25 μM copper sulfate (CuSO(4)). In addition, gene silencing of the copper chaperone for Cu,Zn-superoxide dismutase blocked VEGF expression with little effect on cobalt-induced HIF-1α accumulation. The present study thus demonstrates that copper was required for cobalt-activated transcriptional activity of HIF-1, although copper did not affect cobalt-induced accumulation of HIF-1α in the cells.

  9. Sequential changes of hypoxia- inducible factor 1 alpha in experimental spinal cord injury and its significance

    Institute of Scientific and Technical Information of China (English)

    鞠延; 贺民; 毛伯镛

    2002-01-01

    Objective: To study the sequential changes of HIF-1α(hypoxia-inducible factor 1 alpha) in experimental spinalcord injury in rats and to analyze its potential effects inSCI.Methods: A static compression model of SCI wasemployed in this study. Expressions of HIF-1α weremeasured with immunohistochemical staining, while flowcytometry was used to determine the apoptotic ratio andbcl-2 expressions.Results: HIF-1α began to increase 1 day after injury,and reached the peak at 3-7 days. Two weeks later, itdeclined significantly. The sequential changes of HIF-1αcoincided well with the alterations of apoptotic ratio andcontents of bel-2.Conclusions: HIF-1α possibly participates in thesecondary ischemic and hypoxic procedures after spinalcord injury, and may mediate the traumatic apoptosis.Further understanding of HIF-1α may provide newtherapeutic regimens for SCI.

  10. 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.

  11. Recent Advances in Developing Inhibitors for Hypoxia-Inducible Factor Prolyl Hydroxylases and Their Therapeutic Implications

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    So Yeon Kim

    2015-11-01

    Full Text Available Hypoxia-inducible factor (HIF prolyl hydroxylases (PHDs are members of the 2-oxoglutarate dependent non-heme iron dioxygenases. Due to their physiological roles in regulation of HIF-1α stability, many efforts have been focused on searching for selective PHD inhibitors to control HIF-1α levels for therapeutic applications. In this review, we first describe the structure of PHD2 as a molecular basis for structure-based drug design (SBDD and various experimental methods developed for measuring PHD activity. We further discuss the current status of the development of PHD inhibitors enabled by combining SBDD approaches with high-throughput screening. Finally, we highlight the clinical implications of small molecule PHD inhibitors.

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

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

    2014-07-18

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

  13. Hypoxia inducible factor-1α mediates protective effects of ischemic preconditioning on ECV-304 endothelial cells

    Institute of Scientific and Technical Information of China (English)

    Liu-Bin Shi; Jian-Hua Huang; Bao-San Han

    2007-01-01

    AIM: To investigate whether hypoxia inducible factor-1α (HIF-1α) is linked to the protective effects of ischemic preconditioning (IP) on sinusoidal endothelial cells against ischemia/reperfusion injury.METHODS: Sinusoidal endothelial cell lines ECV-304 were cultured and divided into four groups: control group, cells were cultured in complete DMEM medium; cold anoxia/warm reoxygenation (A/R) group, cells were preserved in a 4℃ UW solution in a mixture of 95% N2 and 5% CO2 for 24 h; anoxia-preconditioning (ARC) group, cells were treated with 4 cycles of short anoxia and reoxygenation before prolonged anoxia-preconditioning treatment; and anoxia-preconditioning and hypoxia inducible factor-1α (HIF-1α) inhibitor (I-HIF-1) group, cells were pretreated with 5 μm of HIF-1α inhibitor NS398 in DMEM medium before subjected to the same treatment as group ARC. After the anoxia treatment, each group was reoxygenated in a mixture of 95% air and 5% CO2 incubator for 6 h. Cytoprotections were evaluated by cell viabilities from Trypan blue, lactate dehydrogenase (LDH) release rates, and intracellular cell adhesion molecule-1 (ICAM-1) expressions. Expressions of HIF-1α mRNA and HIF-1α protein from each group were determined by the RT-PCR method and Western blotting, respectively.RESULTS: Ischemia preconditioning increased cell viability, and reduced LDH release and ICAM-1 expressions. Ischemia preconditioning also upregulated the HIF-1α mRNA level and HIF-1α protein expression. However, all of these changes were reversed by HIF-1α inhibitor NS398.CONCLUSION: Ischemia preconditioning effectively inhibited cold hypoxia/warm reoxygenation injury to endothelial cells, and the authors showed for the first time HIF-1α is causally linked to the protective effects of ischemic preconditioning on endothelial cells.

  14. Hypoxia inducible factor: It’s role in angiogenesis and tumor

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    Mozhgan Jahani

    2016-02-01

    Full Text Available Angiogenesis, as the process of new vessel formation from pre-existing vessels is dependent on a delicate equilibrium between endogenous angiogenic and antiangiogenic factors. However, under pathological conditions, this tight regulation becomes lost which can result in the formation of the different diseases such as cancer. Angiogenesis is a complex process that includes many gene products that are produced by different cells. Each of the processes influenced by specific genes that their expression can be regulated by hypoxi inducible factor-1 (HIF-1. Hypoxia, the imbalance between the oxygen in need and the oxygen available, usually occurs in tumors and ischemic cardiovascular diseases. In order to overcome this challenge, tumors regulate and control the expression of genes related to angiogenesis, cell cycle and metabolism using hypoxia-inducible factor 1 (HIF-1. HIF-1 was first recognized as a transcription factor involved in hypoxia-induced erythropoietin expression. As angiogenesis pathway molecules are being described, this factor has been characterized as a key transcription regulator for these molecules. In this review article, after discussing HIF-1 structure and characterization, the role of this important factor in angiogenesis and cancer as a pathological case and finally, the clinical applications has been evaluated. Articles related to the key words of hypoxia, HIF-1 and angiogenesis were searched from valid databases such as Springer Link, google scholar, Pubmed and Sciencedirect. Then, the articles related to the role of hypoxia and HIF-1 in activation of genes that are involved in angiogenesis and cancer were searched and selected for this study. Studies show that, HIF-1 activation of genes including vascular endothelial growth factor (VEGF, angiopoietin-1 (Ang-1 and angiopoietin-2 (Ang-2, etc., induced angiogenesis in the tumor cells. Furthermore, the activation of genes such as insulin-like growth factor 2 (IGF2

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

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    Mehtap Kilic Eren

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

  16. A viral vector expressing hypoxia-inducible factor 1 alpha inhibits hippocampal neuronal apoptosis

    Institute of Scientific and Technical Information of China (English)

    Xiqing Chai; Weina Kong; Lingyun Liu; Wenguo Yu; Zhenqing Zhang; Yimin Sun

    2014-01-01

    Hypoxia-inducible factor 1 (HIF-1) attenuates amyloid-beta protein neurotoxicity and decreases apoptosis induced by oxidative stress or hypoxia in cortical neurons. In this study, we construct-ed a recombinant adeno-associated virus (rAAV) vector expressing the human HIF-1αgene (rAAV-HIF-1α), and tested the assumption that rAAV-HIF-1αrepresses hippocampal neuronal apoptosis induced by amyloid-beta protein. Our results conifrmed that rAAV-HIF-1αsigniifcant-ly reduces apoptosis induced by amyloid-beta protein in primary cultured hippocampal neurons. Direct intracerebral rAAV-HIF-1αadministration also induced robust and prolonged HIF-1αproduction in rat hippocampus. Single rAAV-HIF-1αadministration resulted in decreased apoptosis of hippocampal neurons in an Alzheimer’s disease rat model established by intrace-rebroventricular injection of aggregated amyloid-beta protein (25-35). Our in vitro and in vivo ifndings demonstrate that HIF-1 has potential for attenuating hippocampal neuronal apoptosis induced by amyloid-beta protein, and provides experimental support for treatment of neurode-generative diseases using gene therapy.

  17. Expression of hypoxia-inducible factor 1 alpha and oligodendrocyte lineage gene-1 in cultured brain slices after oxygen-glucose deprivation

    Institute of Scientific and Technical Information of China (English)

    Hong Cui; Weijuan Han; Lijun Yang; Yanzhong Chang

    2013-01-01

    Oligodendrocyte lineage gene-1 expressed in oligodendrocytes may trigger the repair of neuronal myelin impairment, and play a crucial role in myelin repair. Hypoxia-inducible factor 1α, a transcription factor, is of great significance in premature infants with hypoxic-ischemic brain damage. There is little evidence of direct regulatory effects of hypoxia-inducible factor 1α on oligodendrocyte lineage gene-1. In this study, brain slices of Sprague-Dawley rats were cultured and subjected to oxygen-glucose deprivation. Then, slices were transfected with hypoxia-inducible factor 1α or oligodendrocyte lineage gene-1. The expression levels of hypoxia-inducible factor 1α and oligodendrocyte lineage gene-1 were significantly up-regulated in rat brains prior to transfection, as detected by immunohistochemical staining. Eight hours after transfection of slices with hypoxia-inducible factor 1α, oligodendrocyte lineage gene-1 expression was upregulated, and reached a peak 24 hours after transfection. Oligodendrocyte lineage gene-1 transfection induced no significant differences in hypoxia-inducible factor 1α levels in rat brain tissues with oxygen-glucose deprivation. These experimental findings indicate that hypoxia-inducible factor 1α can regulate oligodendrocyte lineage gene-1 expression in hypoxic brain tissue, thus repairing the neural impairment.

  18. Hypoxia Inducible Factor Pathway and Physiological Adaptation: A Cell Survival Pathway?

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    Hemant Kumar

    2015-01-01

    Full Text Available Oxygen homeostasis reflects the constant body requirement to generate energy. Hypoxia (0.1–1% O2, physioxia or physoxia (∼1–13%, and normoxia (∼20% are terms used to define oxygen concentration in the cellular environment. A decrease in oxygen (hypoxia or excess oxygen (hyperoxia could be deleterious for cellular adaptation and survival. Hypoxia can occur under both physiological (e.g., exercise, embryonic development, underwater diving, or high altitude and pathological conditions (e.g., inflammation, solid tumor formation, lung disease, or myocardial infarction. Hypoxia plays a key role in the pathophysiology of heart disease, cancers, stroke, and other causes of mortality. Hypoxia inducible factor(s (HIFs are key oxygen sensors that mediate the ability of the cell to cope with decreased oxygen tension. These transcription factors regulate cellular adaptation to hypoxia and protect cells by responding acutely and inducing production of endogenous metabolites and proteins to promptly regulate metabolic pathways. Here, we review the role of the HIF pathway as a metabolic adaptation pathway and how this pathway plays a role in cell survival. We emphasize the roles of the HIF pathway in physiological adaptation, cell death, pH regulation, and adaptation during exercise.

  19. Hypoxia Inducible Factor Pathway and Physiological Adaptation: A Cell Survival Pathway?

    Science.gov (United States)

    Kumar, Hemant; Choi, Dong-Kug

    2015-01-01

    Oxygen homeostasis reflects the constant body requirement to generate energy. Hypoxia (0.1-1% O2), physioxia or physoxia (∼1-13%), and normoxia (∼20%) are terms used to define oxygen concentration in the cellular environment. A decrease in oxygen (hypoxia) or excess oxygen (hyperoxia) could be deleterious for cellular adaptation and survival. Hypoxia can occur under both physiological (e.g., exercise, embryonic development, underwater diving, or high altitude) and pathological conditions (e.g., inflammation, solid tumor formation, lung disease, or myocardial infarction). Hypoxia plays a key role in the pathophysiology of heart disease, cancers, stroke, and other causes of mortality. Hypoxia inducible factor(s) (HIFs) are key oxygen sensors that mediate the ability of the cell to cope with decreased oxygen tension. These transcription factors regulate cellular adaptation to hypoxia and protect cells by responding acutely and inducing production of endogenous metabolites and proteins to promptly regulate metabolic pathways. Here, we review the role of the HIF pathway as a metabolic adaptation pathway and how this pathway plays a role in cell survival. We emphasize the roles of the HIF pathway in physiological adaptation, cell death, pH regulation, and adaptation during exercise.

  20. Upregulation of hypoxia-inducible factors in normal and psoriatic skin.

    Science.gov (United States)

    Rosenberger, Christian; Solovan, Caius; Rosenberger, Alina D; Jinping, Li; Treudler, Regina; Frei, Ulrich; Eckardt, Kai-Uwe; Brown, Lawrence F

    2007-10-01

    Angiogenesis induced by vascular endothelial growth factor (VEGF) plays an important role in psoriasis. Hypoxic adaptation is conferred through hypoxia-inducible transcription factors (HIFs). VEGF and its receptor Flt-1 are HIF target genes. Growth factors and inflammatory cytokines activate the phosphoinositol-3 kinase pathway, and via activated protein kinase B (phospho-Akt) augment HIF activity. Here, we demonstrate that the major oxygen-dependent HIF isoforms are strongly upregulated in psoriatic skin: HIF-1alpha mainly in the epidermis, in an expression pattern similar to VEGF mRNA; HIF-2alpha in both the epidermis and in capillary endothelial cells of the dermis. In contrast, normal human skin shows low expression of HIF-alpha proteins, with the exception of hair follicles, and glands, which strongly express HIF-1alpha. In normal human skin, phospho-Akt appeared in the basal epidermal layer, in hair follicles, and in dermal glands. In contrast, in psoriasis, phospho-Akt expression was low in the epidermis, but markedly enhanced in the dermal capillaries and in surrounding interstitial/inflammatory cells. Our data suggest that hypoxia initiates a potentially self-perpetuating cycle involving HIF, VEGF, and Akt activation, which could drive physiologic growth of hair follicles and skin glands. Furthermore, such a cycle may exist in psoriasis in dermal capillaries and contribute to disease progression.

  1. 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.

  2. Hypoxia-inducible factor directs POMC gene to mediate hypothalamic glucose sensing and energy balance regulation.

    Science.gov (United States)

    Zhang, Hai; Zhang, Guo; Gonzalez, Frank J; Park, Sung-Min; Cai, Dongsheng

    2011-07-01

    Hypoxia-inducible factor (HIF) is a nuclear transcription factor that responds to environmental and pathological hypoxia to induce metabolic adaptation, vascular growth, and cell survival. Here we found that HIF subunits and HIF2α in particular were normally expressed in the mediobasal hypothalamus of mice. Hypothalamic HIF was up-regulated by glucose to mediate the feeding control of hypothalamic glucose sensing. Two underlying molecular pathways were identified, including suppression of PHDs by glucose metabolites to prevent HIF2α degradation and the recruitment of AMPK and mTOR/S6K to regulate HIF2α protein synthesis. HIF activation was found to directly control the transcription of POMC gene. Genetic approach was then employed to develop conditional knockout mice with HIF inhibition in POMC neurons, revealing that HIF loss-of-function in POMC neurons impaired hypothalamic glucose sensing and caused energy imbalance to promote obesity development. The metabolic effects of HIF in hypothalamic POMC neurons were independent of leptin signaling or pituitary ACTH pathway. Hypothalamic gene delivery of HIF counteracted overeating and obesity under conditions of nutritional excess. In conclusion, HIF controls hypothalamic POMC gene to direct the central nutrient sensing in regulation of energy and body weight balance.

  3. Hypoxia-inducible factor directs POMC gene to mediate hypothalamic glucose sensing and energy balance regulation.

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    Hai Zhang

    2011-07-01

    Full Text Available Hypoxia-inducible factor (HIF is a nuclear transcription factor that responds to environmental and pathological hypoxia to induce metabolic adaptation, vascular growth, and cell survival. Here we found that HIF subunits and HIF2α in particular were normally expressed in the mediobasal hypothalamus of mice. Hypothalamic HIF was up-regulated by glucose to mediate the feeding control of hypothalamic glucose sensing. Two underlying molecular pathways were identified, including suppression of PHDs by glucose metabolites to prevent HIF2α degradation and the recruitment of AMPK and mTOR/S6K to regulate HIF2α protein synthesis. HIF activation was found to directly control the transcription of POMC gene. Genetic approach was then employed to develop conditional knockout mice with HIF inhibition in POMC neurons, revealing that HIF loss-of-function in POMC neurons impaired hypothalamic glucose sensing and caused energy imbalance to promote obesity development. The metabolic effects of HIF in hypothalamic POMC neurons were independent of leptin signaling or pituitary ACTH pathway. Hypothalamic gene delivery of HIF counteracted overeating and obesity under conditions of nutritional excess. In conclusion, HIF controls hypothalamic POMC gene to direct the central nutrient sensing in regulation of energy and body weight balance.

  4. Hypoxia inducible factors are dispensable for myeloid cell migration into the inflamed mouse eye

    Science.gov (United States)

    Gardner, Peter J.; Liyanage, Sidath E.; Cristante, Enrico; Sampson, Robert D.; Dick, Andrew D.; Ali, Robin R.; Bainbridge, James W.

    2017-01-01

    Hypoxia inducible factors (HIFs) are ubiquitously expressed transcription factors important for cell homeostasis during dynamic oxygen levels. Myeloid specific HIFs are crucial for aspects of myeloid cell function, including their ability to migrate into inflamed tissues during autoimmune disease. This contrasts with the concept that accumulation of myeloid cells at ischemic and hypoxic sites results from a lack of chemotactic responsiveness. Here we seek to address the role of HIFs in myeloid trafficking during inflammation in a mouse model of human uveitis. We show using mice with myeloid-specific Cre-deletion of HIFs that myeloid HIFs are dispensable for leukocyte migration into the inflamed eye. Myeloid-specific deletion of Hif1a, Epas1, or both together, had no impact on the number of myeloid cells migrating into the eye. Additionally, stabilization of HIF pathways via deletion of Vhl in myeloid cells had no impact on myeloid trafficking into the inflamed eye. Finally, we chemically induce hypoxemia via hemolytic anemia resulting in HIF stabilization within circulating leukocytes to demonstrate the dispensable role of HIFs in myeloid cell migration into the inflamed eye. These data suggest, contrary to previous reports, that HIF pathways in myeloid cells during inflammation and hypoxia are dispensable for myeloid cell tissue trafficking. PMID:28112274

  5. Activation of hypoxia inducible factor 1 is a general phenomenon in infections with human pathogens.

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    Nadine Werth

    Full Text Available BACKGROUND: Hypoxia inducible factor (HIF-1 is the key transcriptional factor involved in the adaptation process of cells and organisms to hypoxia. Recent findings suggest that HIF-1 plays also a crucial role in inflammatory and infectious diseases. METHODOLOGY/PRINCIPAL FINDINGS: Using patient skin biopsies, cell culture and murine infection models, HIF-1 activation was determined by immunohistochemistry, immunoblotting and reporter gene assays and was linked to cellular oxygen consumption. The course of a S. aureus peritonitis was determined upon pharmacological HIF-1 inhibition. Activation of HIF-1 was detectable (i in all ex vivo in biopsies of patients suffering from skin infections, (ii in vitro using cell culture infection models and (iii in vivo using murine intravenous and peritoneal S. aureus infection models. HIF-1 activation by human pathogens was induced by oxygen-dependent mechanisms. Small colony variants (SCVs of S. aureus known to cause chronic infections did not result in cellular hypoxia nor in HIF-1 activation. Pharmaceutical inhibition of HIF-1 activation resulted in increased survival rates of mice suffering from a S. aureus peritonitis. CONCLUSIONS/SIGNIFICANCE: Activation of HIF-1 is a general phenomenon in infections with human pathogenic bacteria, viruses, fungi and protozoa. HIF-1-regulated pathways might be an attractive target to modulate the course of life-threatening infections.

  6. Hypoxia-inducible factor-1a restricts the anabolic actions of parathyroid hormone

    Institute of Scientific and Technical Information of China (English)

    Julie L Frey; David P Stonko; Marie-Claude Faugere; Ryan C Riddle

    2014-01-01

    The hypoxia inducible factors (Hifs) are evolutionarily conserved transcriptional factors that control homeostatic responses to low oxygen. In developing bone, Hif-1 generated signals induce angiogenesis necessary for osteoblast specification, but in mature bone, loss of Hif-1 in osteoblasts resulted in a more rapid accumulation of bone. These findings suggested that Hif-1 exerts distinct developmental functions and acts as a negative regulator of bone formation. To investigate the function of Hif-1a in osteoanabolic signaling, we assessed the effect of Hif-1a loss-of-function on bone formation in response to intermittent parathyroid hormone (PTH). Mice lacking Hif-1a in osteoblasts and osteocytes form more bone in response to PTH, likely through a larger increase in osteoblast activity and increased sensitivity to the hormone. Consistent with this effect, exposure of primary mouse osteoblasts to PTH resulted in the rapid induction of Hif-1a protein levels via a post-transcriptional mechanism. The enhanced anabolic response appears to result from the removal of Hif-1a-mediated suppression of b-catenin transcriptional activity. Together, these data indicate that Hif-1a functions in the mature skeleton to restrict osteoanabolic signaling. The availability of pharmacological agents that reduce Hif-1a function suggests the value in further exploration of this pathway to optimize the therapeutic benefits of PTH.

  7. Regulation of hypoxia-inducible factor-1α in human buccal mucosal fibroblasts stimulated with arecoline

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    Yung-Chuan Ho

    2017-06-01

    Full Text Available Hypoxia-inducible factor (HIF-1α is consistently and dramatically upregulated in a variety of fibrotic diseases. The aim of this study was to compare HIF-1α expression from fibroblasts derived from human normal buccal mucosa and oral submucous fibrosis (OSF specimens and further to explore the potential mechanisms that may lead to induce HIF-1α expression. OSF buccal mucosal fibroblasts (BMFs demonstrated significantly higher HIF-1α mRNA expression than normal BMFs (p<0.005. Arecoline, the major areca nut alkaloid, was also found to elevate HIF-1α mRNA expression in a dose-dependent manner (p<0.05. Moreover, arecoline-induced HIF-1α expression was downregulated by mitogen-activated protein kinase inhibitor U0126, phosphatidylinositol 3-kinase inhibitor LY294002, p38 inhibitor SB203580, cyclooxygenase-2 inhibitor NS-398, and glutathione precursor N-acetyl-L-cysteine (p<0.05. Taken together, hypoxia plays an important role in the pathogenesis of areca quid chewing-associated OSF. These pharmacological agents may be further used as chemoprevention agents for OSF.

  8. Differential Expression of Three Hypoxia-inducible Factor-α Subunits in Pulmonary Arteries of Rat with Hypoxia-induced Hypertension

    Institute of Scientific and Technical Information of China (English)

    Qi-Fang LI; Ai-Guo DAI

    2005-01-01

    Hypoxia inducible transcription factor (HIF)-1α plays an important role in the development of hypoxic pulmonary hypertension, but little is known about HIF-2α and HIF-3α with respect to transcriptional regulation by hypoxia. To examine the expression patterns of all HIF-α subunits (HIF-1α, HIF-2α and HIF-3α) in pulmonary arteries of rats undergoing systemic hypoxia, five groups of healthy male Wistar rats were exposed to normoxia (N) and hypoxia for 3 (H3), 7 (H7), 14 (H14) and 21 (H21) d respectively. Mean pulmonary arterial pressure (mPAP), vessel morphometry and right ventricular hypertrophy index were measured. Lungs were inflation fixed for immunohistochemistry and in situ hybridization, and homogenized for Western blot. mPAP increased significantly after 7 d of hypoxia [(18.4±0.4) vs. (14.4±0.4) mmHg, H7 vs.N], reached its peak after 14 d of hypoxia, then remained stable. Pulmonary artery remodeling and right ventricular hypertrophy developed significantly after 14 d of hypoxia. During normoxia, HIF-1 α and HIF-3α staining were slightly positive regarding mRNA levels. A substantial alteration of HIF-1 α and HIF-3α staining occurred in pulmonary arteries after 14 d and 7 d of hypoxia, respectively, but HIF-2α stainin g showed an inversed trend after 14 d of hypoxia. Protein levels of all HIF-α subunits except HIF-3α showed a marked increase corresponding to the duration of hypoxia, which was obtained by Western blot. Our study found that HIF-1 α, HIF-2α and HIF-3α may not only confer different target genes, but also play key pathogenetic roles in hypoxic-induced pulmonary hypertension.

  9. Hypoxia-inducible factor-2α is an essential catabolic regulator of inflammatory rheumatoid arthritis.

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    Je-Hwang Ryu

    2014-06-01

    Full Text Available Rheumatoid arthritis (RA is a systemic autoimmune disorder that manifests as chronic inflammation and joint tissue destruction. However, the etiology and pathogenesis of RA have not been fully elucidated. Here, we explored the role of the hypoxia-inducible factors (HIFs, HIF-1α (encoded by HIF1A and HIF-2α (encoded by EPAS1. HIF-2α was markedly up-regulated in the intimal lining of RA synovium, whereas HIF-1α was detected in a few cells in the sublining and deep layer of RA synovium. Overexpression of HIF-2α in joint tissues caused an RA-like phenotype, whereas HIF-1α did not affect joint architecture. Moreover, a HIF-2α deficiency in mice blunted the development of experimental RA. HIF-2α was expressed mainly in fibroblast-like synoviocytes (FLS of RA synovium and regulated their proliferation, expression of RANKL (receptor activator of nuclear factor-κB ligand and various catabolic factors, and osteoclastogenic potential. Moreover, HIF-2α-dependent up-regulation of interleukin (IL-6 in FLS stimulated differentiation of TH17 cells-crucial effectors of RA pathogenesis. Additionally, in the absence of IL-6 (Il6-/- mice, overexpression of HIF-2α in joint tissues did not cause an RA phenotype. Thus, our results collectively suggest that HIF-2α plays a pivotal role in the pathogenesis of RA by regulating FLS functions, independent of HIF-1α.

  10. Cancer drug troglitazone stimulates the growth and response of renal cells to hypoxia inducible factors

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    Taub, Mary, E-mail: biochtau@buffalo.edu

    2016-03-11

    Troglitazone has been used to suppress the growth of a number of tumors through apoptosis and autophagy. However, previous in vitro studies have employed very high concentrations of troglitazone (≥10{sup −5} M) in order to elicit growth inhibitory effects. In this report, when employing lower concentrations of troglitazone in defined medium, troglitazone was observed to stimulate the growth of primary renal proximal tubule (RPT) cells. Rosiglitazone, like troglitazone, is a thiazolidinedione (TZD) that is known to activate Peroxisome Proliferator Activated Receptor Υ (PPARΥ). Notably, rosiglitazone also stimulates RPT cell growth, as does Υ-linolenic acids, another PPARΥ agonist. The PPARΥ antagonist GW9662 inhibited the growth stimulatory effect of troglitazone. In addition, troglitazone stimulated transcription by a PPAR Response Element/Luciferase construct. These results are consistent with the involvement of PPARΥ as a mediator of the growth stimulatory effect of troglitazone. In a number of tumor cells, the expression of hypoxia inducible factor (HIF) is increased, promoting the expression of HIF inducible genes, and vascularization. Troglitazone was observed to stimulate transcription by a HIF/luciferase construct. These observations indicate that troglitazone not only promotes growth, also the survival of RPT cells under conditions of hypoxia. - Highlights: • Troglitazone and rosiglitazone stimulate renal proximal tubule cell growth. • Troglitazone and linolenic acid stimulate growth via PPARϒ. • Linolenic acid stimulates growth in the presence of fatty acid free serum albumin. • Rosiglitazone stimulates transcription by a HRE luciferase construct.

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

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    Mushfiquddin Khan

    2017-01-01

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

  12. Interplay between sirtuins, MYC and hypoxia-inducible factor in cancer-associated metabolic reprogramming

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    Bernadette M. M. Zwaans

    2014-09-01

    Full Text Available In the early twentieth century, Otto Heinrich Warburg described an elevated rate of glycolysis occurring in cancer cells, even in the presence of atmospheric oxygen (the Warburg effect. Despite the inefficiency of ATP generation through glycolysis, the breakdown of glucose into lactate provides cancer cells with a number of advantages, including the ability to withstand fluctuations in oxygen levels, and the production of intermediates that serve as building blocks to support rapid proliferation. Recent evidence from many cancer types supports the notion that pervasive metabolic reprogramming in cancer and stromal cells is a crucial feature of neoplastic transformation. Two key transcription factors that play major roles in this metabolic reprogramming are hypoxia inducible factor-1 (HIF1 and MYC. Sirtuin-family deacetylases regulate diverse biological processes, including many aspects of tumor biology. Recently, the sirtuin SIRT6 has been shown to inhibit the transcriptional output of both HIF1 and MYC, and to function as a tumor suppressor. In this Review, we highlight the importance of HIF1 and MYC in regulating tumor metabolism and their regulation by sirtuins, with a main focus on SIRT6.

  13. Molecular characterisation, evolution and expression of hypoxia-inducible factor in Aurelia sp.1.

    Science.gov (United States)

    Wang, Guoshan; Yu, Zhigang; Zhen, Yu; Mi, Tiezhu; Shi, Yan; Wang, Jianyan; Wang, Minxiao; Sun, Song

    2014-01-01

    The maintenance of physiological oxygen homeostasis is mediated by hypoxia-inducible factor (HIF), a key transcriptional factor of the PHD-HIF system in all metazoans. However, the molecular evolutionary origin of this central physiological regulatory system is not well characterized. As the earliest eumetazoans, Cnidarians can be served as an interesting model for exploring the HIF system from an evolutionary perspective. We identified the complete cDNA sequence of HIF-1α (ASHIF) from the Aurelia sp.1, and the predicted HIF-1α protein (pASHIF) was comprised of 674 amino acids originating from 2,025 bp nucleotides. A Pairwise comparison revealed that pASHIF not only possessed conserved basic helix-loop-helix (bHLH) and Per-Arnt-Sim (PAS) domains but also contained the oxygen dependent degradation (ODD) and the C-terminal transactivation domains (C-TAD), the key domains for hypoxia regulation. As indicated by sequence analysis, the ASHIF gene contains 8 exons interrupted by 7 introns. Western blot analysis indicated that pASHIF that existed in the polyps and medusa of Aurelia. sp.1 was more stable for a hypoxic response than normoxia.

  14. Myeloid translocation gene-16 co-repressor promotes degradation of hypoxia-inducible factor 1.

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    Parveen Kumar

    Full Text Available The myeloid translocation gene 16 (MTG16 co-repressor down regulates expression of multiple glycolytic genes, which are targets of the hypoxia-inducible factor 1 (HIF1 heterodimer transcription factor that is composed of oxygen-regulated labile HIF1α and stable HIF1β subunits. For this reason, we investigated whether MTG16 might regulate HIF1 negatively contributing to inhibition of glycolysis and stimulation of mitochondrial respiration. A doxycycline Tet-On system was used to control levels of MTG16 in B-lymphoblastic Raji cells. Results from co-association studies revealed MTG16 to interact with HIF1α. The co-association required intact N-terminal MTG16 residues including Nervy Homology Region 1 (NHR1. Furthermore, electrophoretic mobility shift assays demonstrated an association of MTG16 with hypoxia response elements (HREs in PFKFB3, PFKFB4 and PDK1 promoters in-vitro. Results from chromatin immunoprecipitation assays revealed co-occupancy of these and other glycolytic gene promoters by HIF1α, HIF1β and MTG16 in agreement with possible involvement of these proteins in regulation of glycolytic target genes. In addition, MTG16 interacted with prolyl hydroxylase D2 and promoted ubiquitination and proteasomal degradation of HIF1α. Our findings broaden the area of MTG co-repressor functions and reveal MTG16 to be part of a protein complex that controls the levels of HIF1α.

  15. Myeloid derived hypoxia inducible factor 1-alpha is required for protection against pulmonary Aspergillus fumigatus infection.

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    Kelly M Shepardson

    2014-09-01

    Full Text Available Hypoxia inducible factor 1α (HIF1α is the mammalian transcriptional factor that controls metabolism, survival, and innate immunity in response to inflammation and low oxygen. Previous work established that generation of hypoxic microenvironments occurs within the lung during infection with the human fungal pathogen Aspergillus fumigatus. Here we demonstrate that A. fumigatus stabilizes HIF1α protein early after pulmonary challenge that is inhibited by treatment of mice with the steroid triamcinolone. Utilizing myeloid deficient HIF1α mice, we observed that HIF1α is required for survival and fungal clearance early following pulmonary challenge with A. fumigatus. Unlike previously reported research with bacterial pathogens, HIF1α deficient neutrophils and macrophages were surprisingly not defective in fungal conidial killing. The increase in susceptibility of the myeloid deficient HIF1α mice to A. fumigatus was in part due to decreased early production of the chemokine CXCL1 (KC and increased neutrophil apoptosis at the site of infection, resulting in decreased neutrophil numbers in the lung. Addition of recombinant CXCL1 restored neutrophil survival and numbers, murine survival, and fungal clearance. These results suggest that there are unique HIF1α mediated mechanisms employed by the host for protection and defense against fungal pathogen growth and invasion in the lung. Additionally, this work supports the strategy of exploring HIF1α as a therapeutic target in specific immunosuppressed populations with fungal infections.

  16. Myeloid derived hypoxia inducible factor 1-alpha is required for protection against pulmonary Aspergillus fumigatus infection.

    Science.gov (United States)

    Shepardson, Kelly M; Jhingran, Anupam; Caffrey, Alayna; Obar, Joshua J; Suratt, Benjamin T; Berwin, Brent L; Hohl, Tobias M; Cramer, Robert A

    2014-09-01

    Hypoxia inducible factor 1α (HIF1α) is the mammalian transcriptional factor that controls metabolism, survival, and innate immunity in response to inflammation and low oxygen. Previous work established that generation of hypoxic microenvironments occurs within the lung during infection with the human fungal pathogen Aspergillus fumigatus. Here we demonstrate that A. fumigatus stabilizes HIF1α protein early after pulmonary challenge that is inhibited by treatment of mice with the steroid triamcinolone. Utilizing myeloid deficient HIF1α mice, we observed that HIF1α is required for survival and fungal clearance early following pulmonary challenge with A. fumigatus. Unlike previously reported research with bacterial pathogens, HIF1α deficient neutrophils and macrophages were surprisingly not defective in fungal conidial killing. The increase in susceptibility of the myeloid deficient HIF1α mice to A. fumigatus was in part due to decreased early production of the chemokine CXCL1 (KC) and increased neutrophil apoptosis at the site of infection, resulting in decreased neutrophil numbers in the lung. Addition of recombinant CXCL1 restored neutrophil survival and numbers, murine survival, and fungal clearance. These results suggest that there are unique HIF1α mediated mechanisms employed by the host for protection and defense against fungal pathogen growth and invasion in the lung. Additionally, this work supports the strategy of exploring HIF1α as a therapeutic target in specific immunosuppressed populations with fungal infections.

  17. Hypoxia-inducible factor plays a gut-injurious role in intestinal ischemia reperfusion injury.

    Science.gov (United States)

    Kannan, Kolenkode B; Colorado, Iriana; Reino, Diego; Palange, David; Lu, Qi; Qin, Xiaofa; Abungu, Billy; Watkins, Anthony; Caputo, Francis J; Xu, Da-Zhong; Semenza, Gregg L; Deitch, Edwin A; Feinman, Rena

    2011-05-01

    Gut injury and loss of normal intestinal barrier function are key elements in the paradigm of gut-origin systemic inflammatory response syndrome, acute lung injury, and multiple organ dysfunction syndrome (MODS). As hypoxia-inducible factor (HIF-1) is a critical determinant of the physiological and pathophysiological response to hypoxia and ischemia, we asked whether HIF-1 plays a proximal role in the induction of gut injury and subsequent lung injury. Using partially HIF-1α-deficient mice in an isolated superior mesenteric artery occlusion (SMAO) intestinal ischemia reperfusion (I/R) injury model (45 min SMAO followed by 3 h of reperfusion), we showed a direct relationship between HIF-1 activation and intestinal I/R injury. Specifically, partial HIF-1α deficiency attenuated SMAO-induced increases in intestinal permeability, lipid peroxidation, mucosal caspase-3 activity, and IL-1β mRNA levels. Furthermore, partial HIF-1α deficiency prevented the induction of ileal mucosal inducible nitric oxide synthase (iNOS) protein levels after SMAO and iNOS deficiency ameliorated SMAO-induced villus injury. Resistance to SMAO-induced gut injury was also associated with resistance to lung injury, as reflected by decreased levels of myeloperoxidase, IL-6 and IL-10 in the lungs of HIF-1α(+/-) mice. In contrast, a short duration of SMAO (15 min) followed by 3 h of reperfusion neither induced mucosal HIF-1α protein levels nor caused significant gut and lung injury in wild-type or HIF-1α(+/-) mice. This study indicates that intestinal HIF-1 activation is a proximal regulator of I/R-induced gut mucosal injury and gut-induced lung injury. However, the duration and severity of the gut I/R insult dictate whether HIF-1 plays a gut-protective or deleterious role.

  18. Cell physiology regulation by hypoxia inducible factor-1: Targeting oxygen-related nanomachineries of hypoxic cells.

    Science.gov (United States)

    Eskandani, Morteza; Vandghanooni, Somayeh; Barar, Jaleh; Nazemiyeh, Hossein; Omidi, Yadollah

    2017-06-01

    Any dysfunctionality in maintaining the oxygen homeostasis by mammalian cells may elicit hypoxia/anoxia, which results in inescapable oxidative stress and possible subsequent detrimental impacts on certain cells/tissues with high demands to oxygen molecules. The ischemic damage in turn can trigger initiation of a number of diseases including organs ischemia, metabolic disorders, inflammatory diseases, different types of malignancies, and alteration in wound healing process. Thus, full comprehension of molecular mechanism(s) and cellular physiology of the oxygen homeostasis is the cornerstone of the mammalian cells metabolism, energetic pathways and health and disease conditions. An imbalance in oxygen content within the cellular microenvironment activates a cascade of molecular events that are often compensated, otherwise pathologic condition occurs through a complexed network of biomolecules. Hypoxia inducible factor-1 (HIF-1) plays a key transcriptional role in the adaptation of cell physiology in relation with the oxygen content within a cell. In this current study, we provide a comprehensive review on the molecular mechanisms of oxygen sensing and homeostasis and the impacts of HIF-1 in hypoxic/anoxic conditions. Moreover, different molecular and biochemical responses of the cells to the surrounding environment are discussed in details. Finally, modern technological approaches for targeting the hypoxia related proteins are articulated. Copyright © 2017. Published by Elsevier B.V.

  19. Interleukin-1β, cyclooxygenase-2, and hypoxia-inducible factor-1α in asthenozoospermia.

    Science.gov (United States)

    Salvolini, Eleonora; Buldreghini, Eddi; Lucarini, Guendalina; Vignini, Arianna; Giulietti, Alessia; Lenzi, Andrea; Mazzanti, Laura; Di Primio, Roberto; Balercia, Giancarlo

    2014-11-01

    Impaired male fertility may have a variety of causes, among which asthenozoospermia. In its etiology, several bioactive substances, such as cytokines may be involved. In this context, our aim was to evaluate the expression of interleukin-1β, cyclooxygenase-2, and hypoxia-inducible factor-1α, in spermatozoa isolated from normospermic fertile donors and asthenozoospermic infertile patients. We evaluated twenty-eight infertile patients affected by idiopathic asthenozoospermia and twenty-three normospermic fertile donors, age-matched. Sperm parameters were evaluated; immunohistochemical analysis and enzyme-linked immunosorbent assay were then performed in isolated spermatozoa. Spermatozoa from the asthenozoospermic group presented an increased expression of IL-1β, COX-2, and HIF-1α compared with the normospermic fertile subjects. Our results can lead us to speculate that the increased expression of these substances may influence sperm motility. Nevertheless, further studies are needed in order to assess whether these bioactive mediators have a potential relevance as targets in future therapeutic strategies for the treatment of male infertility.

  20. Hypoxia-Inducible Factors: Mediators of Cancer Progression; Prognostic and Therapeutic Targets in Soft Tissue Sarcomas

    Energy Technology Data Exchange (ETDEWEB)

    Sadri, Navid; Zhang, Paul J., E-mail: pjz@mail.med.upenn.edu [Anatomic Pathology, Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania, 3400 Spruce Street, 6th Floor Founders Building, Philadelphia, PA 19104 (United States)

    2013-04-02

    Soft-tissue sarcomas remain aggressive tumors that result in death in greater than a third of patients due to either loco-regional recurrence or distant metastasis. Surgical resection remains the main choice of treatment for soft tissue sarcomas with pre- and/or post-operational radiation and neoadjuvant chemotherapy employed in more advanced stage disease. However, in recent decades, there has been little progress in the average five-year survival for the majority of patients with high-grade soft tissue sarcomas, highlighting the need for improved targeted therapeutic agents. Clinical and preclinical studies demonstrate that tumor hypoxia and up-regulation of hypoxia-inducible factors (HIFs) is associated with decreased survival, increased metastasis, and resistance to therapy in soft tissue sarcomas. HIF-mediated gene expression regulates many critical aspects of tumor biology, including cell survival, metabolic programming, angiogenesis, metastasis, and therapy resistance. In this review, we discuss HIFs and HIF-mediated genes as potential prognostic markers and therapeutic targets in sarcomas. Many pharmacological agents targeting hypoxia-related pathways are in development that may hold therapeutic potential for treating both primary and metastatic sarcomas that demonstrate increased HIF expression.

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

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    Masashi Ueda

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Laura M. S. Seeber

    2010-01-01

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

  3. Hypoxia-inducible factor-1a contributes to dendritic overgrowth in tuberous sclerosis.

    Science.gov (United States)

    Zhang, Longbo; Feliciano, David M; Huang, Tianxiang; Zhang, Shiliang; Bordey, Angélique

    2016-01-26

    Expression of hypoxia-inducible factor 1a (HIF1a) is increased under several pathological conditions such as hyperactive mechanistic target of rapamycin complex 1 (mTORC1) in tuberous sclerosis complex (TSC). Hyperactive mTORC1 and the resulting increased dendritic complexity of neurons are shared molecular and cellular alterations in several neurological disorders associated with cognitive disabilities. Despite some evidence that HIF1a contributes to dendritic overgrowth in vitro, it remains unknown whether increased HIF1a in TSC neurons could contribute to their increased dendritic complexity. To address this use in vivo, we generated TSC neurons by deleting Tsc1 in newborn olfactory bulb (OB) neurons of conditional Tsc1 transgenic mice using neonatal electroporation. In addition to their increased dendritic complexity, Tsc1(null) neurons have been reported to display increased Hif1a mRNA level and HIF1a transcriptional activity. We found that Tsc1(null)-dependent dendritic overgrowth was prevented by knocking down HIF1a or expressing a dominant negative HIF1a. In addition, overexpressing HIF1a in wild-type developing neurons resulted in increased dendritic complexity in vivo. These data highlight that an increase in HIF1a levels contributes to abnormal dendritic patterning in developing neurons under normal conditions and hyperactive mTORC1 conditions as in TSC.

  4. Hypoxia inducible factors 1 and 2 are important transcriptional effectors in primary macrophages experiencing hypoxia

    Science.gov (United States)

    Fang, Hsin-Yu; Hughes, Russell; Murdoch, Craig; Coffelt, Seth; Biswas, Subhra K.; Harris, Adrian L.; Johnson, Randall S.; Imityaz, Hongxia Z.; Simon, M. Celeste; Fredlund, Erik; Greten, Florian; Rius, Jordi; Lewis, Claire E.

    2010-01-01

    Ischemia exists in many diseased tissues including arthritic joints, atherosclerotic plaques and malignant tumors. Macrophages accumulate in these sites and upregulate hypoxia-inducible transcription factors (HIFs) 1 and 2 in response to the hypoxia present. Here we show that the gene expression profile in primary human and murine macrophages changes markedly when they are exposed to hypoxia for 18h. For example, they were seen to upregulate the cell surface receptors, CXCR4 and GLUT1, and the potent, tumor-promoting cytokines, VEGFA, interleukins 1β and 8, adrenomedullin, CXCR4 and angiopoietin-2. Hypoxia also stimulated their expression and/or phosphorylation of various proteins in the NF-κB signalling pathway. We then used both genetic and pharmacological methods to manipulate the levels of HIFs 1α and 2α or NF-κB in primary macrophages in order to elucidate their role in the hypoxic induction of many of these key genes. These studies showed that both HIFs 1 and 2, but not NF-κB, are important transcriptional effectors regulating the responses of macrophages to such a period of hypoxia. Further studies using experimental mouse models are now warranted to investigate the role of such macrophage responses in the progression of various diseased tissues like malignant tumors. PMID:19454749

  5. Cellular Oxygen Sensing: Crystal Structure of Hypoxia-Inducible Factor Prolyl Hydroxylase (PHD2)

    Energy Technology Data Exchange (ETDEWEB)

    McDonough,M.; Li, V.; Flashman, E.; Chowdhury, R.; Mohr, C.; Lienard, B.; Zondlo, J.; Oldham, N.; Clifton, I.; et al.

    2006-01-01

    Cellular and physiological responses to changes in dioxygen levels in metazoans are mediated via the posttranslational oxidation of hypoxia-inducible transcription factor (HIF). Hydroxylation of conserved prolyl residues in the HIF-{alpha} subunit, catalyzed by HIF prolyl-hydroxylases (PHDs), signals for its proteasomal degradation. The requirement of the PHDs for dioxygen links changes in dioxygen levels with the transcriptional regulation of the gene array that enables the cellular response to chronic hypoxia; the PHDs thus act as an oxygen-sensing component of the HIF system, and their inhibition mimics the hypoxic response. We describe crystal structures of the catalytic domain of human PHD2, an important prolyl-4-hydroxylase in the human hypoxic response in normal cells, in complex with Fe(II) and an inhibitor to 1.7 Angstroms resolution. PHD2 crystallizes as a homotrimer and contains a double-stranded {beta}-helix core fold common to the Fe(II) and 2-oxoglutarate-dependant dioxygenase family, the residues of which are well conserved in the three human PHD enzymes (PHD 1-3). The structure provides insights into the hypoxic response, helps to rationalize a clinically observed mutation leading to familial erythrocytosis, and will aid in the design of PHD selective inhibitors for the treatment of anemia and ischemic disease.

  6. Myeloid-Derived Vascular Endothelial Growth Factor and Hypoxia-Inducible Factor Are Dispensable for Ocular Neovascularization—Brief Report

    Science.gov (United States)

    Liyanage, Sidath E.; Fantin, Alessandro; Villacampa, Pilar; Lange, Clemens A.; Denti, Laura; Cristante, Enrico; Smith, Alexander J.; Ali, Robin R.; Luhmann, Ulrich F.

    2016-01-01

    Objective— Ocular neovascularization (ONV) is a pathological feature of sight-threatening human diseases, such as diabetic retinopathy and age-related macular degeneration. Macrophage depletion in mouse models of ONV reduces the formation of pathological blood vessels, and myeloid cells are widely considered an important source of the vascular endothelial growth factor A (VEGF). However, the importance of VEGF or its upstream regulators hypoxia-inducible factor-1α (HIF1α) and hypoxia-inducible factor-2α (HIF2α) as myeloid-derived regulators of ONV remains to be determined. Approach and Results— We used 2 mouse models of ONV, choroidal neovascularization and oxygen-induced retinopathy, to show that Vegfa is highly expressed by several cell types, but not myeloid cells during ONV. Moreover, myeloid-specific VEGF ablation did not reduce total ocular VEGF during choroidal neovascularization or oxygen-induced retinopathy. In agreement, the conditional inactivation of Vegfa, Hif1a, or Epas1 in recruited and resident myeloid cells that accumulated at sites of neovascularization did not significantly reduce choroidal neovascularization or oxygen-induced retinopathy. Conclusions— The finding that myeloid cells are not a significant local source of VEGF in these rodent models of ONV suggests that myeloid function in neovascular eye disease differs from skin wound healing and other neovascular pathologies. PMID:26603154

  7. Emodin Decreases Hepatic Hypoxia-Inducible Factor-1[Formula: see text] by Inhibiting its Biosynthesis.

    Science.gov (United States)

    Ma, Feifei; Hu, Lijuan; Yu, Ming; Wang, Feng

    2016-01-01

    Hypoxia-inducible factor-1 (HIF-1) is an [Formula: see text] dimeric transcription factor. Because HIF-1[Formula: see text] is instable with oxygen, HIF-1 is scarce in normal mammalian cells. However, HIF-1[Formula: see text] is expressed in pathological conditions such as cancer and obesity. Inhibiting HIF-1[Formula: see text] may be of therapeutic value for these pathologies. Here, we investigated whether emodin, derived from the herb of Rheum palmatum L, which is also known as Chinese rhubarb, and is native to China, regulates HIF-1[Formula: see text] expression. Male C57BL/6 mice without or with diet-induced obesity were treated with emodin for two weeks, while control mice were treated with vehicle. HIF-1[Formula: see text] expression was determined by Western blot. We found that emodin inhibited obesity-induced HIF-1[Formula: see text] expression in liver and skeletal muscle but did not regulate HIF-1[Formula: see text] expression in the kidneys or in intra-abdominal fat. In vitro, emodin inhibited HIF-1[Formula: see text] expression in human HepG2 hepatic cells and Y1 adrenocortical cells. Further, we investigated the mechanisms of HIF-1[Formula: see text] expression in emodin-treated HepG2 cells. First, we found that HIF-1[Formula: see text] had normal stability in the presence of emodin. Thus, emodin did not decrease HIF-1[Formula: see text] by stimulating its degradation. Importantly, emodin decreased the activity of the signaling pathways that led to HIF-1[Formula: see text] biosynthesis. Interestingly, emodin increased HIF-1[Formula: see text] mRNA in HepG2 cells. This may be a result of feedback in response to the emodin-induced decrease in the protein of HIF-1[Formula: see text]. In conclusion, emodin decreases hepatic HIF-1[Formula: see text] by inhibiting its biosynthesis.

  8. Hypoxia inducible factor-1alpha mediates protection of DL-3-n-butylphthalide in brain microvascular endothelial cells against oxygen glucose deprivation-induced injury

    Institute of Scientific and Technical Information of China (English)

    Weihong Yang; Ling Li; Ruxun Huang; Zhong Pei; Songjie Liao; Jinsheng Zeng

    2012-01-01

    Studies have demonstrated that DL-3-n-butylphthalide can significantly alleviate oxygen glucose deprivation-induced injury of human umbilical vein endothelial cells at least partly associated with its enhancement on oxygen glucose deprivation -induced hypoxia inducible factor-1α expression. In this study, we hypothesized that DL-3-n-butylphthalide can protect against oxygen glucose deprivation-induced injury of newborn rat brain microvascular endothelial cells by means of upregulating hypoxia inducible factor-1α expression. MTT assay and Hoechst staining results showed that DL-3-n-butylphthalide protected brain microvascular endothelial cells against oxygen glucose deprivation-induced injury in a dose-dependent manner. Western blot and immunofluorescent staining results further confirmed that the protective effect was related to upregulation of hypoxia inducible factor-1α. Real-time RT-PCR reaction results showed that DL-3-n-butylphthalide reduced apoptosis by inhibiting downregulation of pro-apoptotic gene caspase-3 mRNA expression and upregulation of apoptosis-executive protease bcl-2 mRNA expression; however, DL-3-n-butylphthalide had no protective effects on brain microvascular endothelial cells after knockdown of hypoxia inducible factor-1α by small interfering RNA. These findings suggest that DL-3-n-butylphthalide can protect brain microvascular endothelial cells against oxygen glucose deprivation-induced injury by upregulating bcl-2 expression and downregulating caspase-3 expression though hypoxia inducible factor-1α pathway.

  9. Discovery of Indenopyrazoles as a New Class of Hypoxia Inducible Factor (HIF)-1 Inhibitors

    Science.gov (United States)

    2013-01-01

    The indenopyrazole framework was investigated as a new class of HIF-1α inhibitors. Indenopyrazole 2l was found to most strongly inhibit the hypoxia-induced HIF-1α transcriptional activity (IC50 = 0.014 μM) among all of the known compounds having relatively simple structures, unlike manassantins. Indenopyrazole 2l suppressed HIF-1α transcriptional activity without affecting both HIF-1α protein accumulation and HIF-1α/HIF-1β heterodimerization in nuclei under the hypoxic conditions, suggesting that 2l probably affected the transcriptional pathway induced by the HIF-1α/HIF-1β heterodimer. PMID:24900662

  10. LXY6090 – a novel manassantin A derivative – limits breast cancer growth through hypoxia-inducible factor-1 inhibition

    OpenAIRE

    Lai, Fangfang; Liu, Qian; LIU, Xiaoyu; Ji, Ming; Xie, Ping; Chen, Xiaoguang

    2016-01-01

    Hypoxia-inducible factor-1 (HIF-1) represents a novel antitumor target owing to its involvement in vital processes considered hallmarks of cancer phenotypes. Manassantin A (MA) derived from Saururus cernuus has been reported as a selective HIF-1 inhibitor. Herein, the structure of MA was optimized to achieve new derivatives with simple chemical properties while retaining its activity. LXY6090 was designed to replace the central tetrahydrofuran moiety of MA with a cyclopentane ring and was ide...

  11. Therapeutic treatment with a novel hypoxia-inducible factor hydroxylase inhibitor (TRC160334) ameliorates murine colitis

    Science.gov (United States)

    Gupta, Ram; Chaudhary, Anita R; Shah, Binita N; Jadhav, Avinash V; Zambad, Shitalkumar P; Gupta, Ramesh Chandra; Deshpande, Shailesh; Chauthaiwale, Vijay; Dutt, Chaitanya

    2014-01-01

    Background and aim Mucosal healing in inflammatory bowel disease (IBD) can be achieved by improvement of intestinal barrier protection. Activation of hypoxia-inducible factor (HIF) has been identified as a critical factor for barrier protection during mucosal insult and is linked with improvement in symptoms of colitis. Although prophylactic efficacy of HIF hydroxylase inhibitors in murine colitis have been established, its therapeutic efficacy in clinically relevant therapeutic settings have not been established. In the present study we aim to establish therapeutic efficacy of TRC160334, a novel HIF hydroxylase inhibitor, in animal models of colitis. Methods The efficacy of TRC160334 was evaluated in two different mouse models of colitis by oral route. A prophylactic efficacy study was performed in a 2,4,6-trinitrobenzene sulfonic acid-induced mouse model of colitis representing human Crohn’s disease pathology. Additionally, a therapeutic efficacy study was performed in a dextran sulfate sodium-induced mouse model of colitis, a model simulating human ulcerative colitis. Results TRC160334 treatment resulted in significant improvement in disease end points in both models of colitis. TRC160334 treatment resulted into cytoprotective heatshock protein 70 induction in inflamed colon. TRC160334 successfully attenuated the rate of fall in body weight, disease activity index, and macroscopic and microscopic scores of colonic damage leading to overall improvement in study outcome. Conclusion Our findings are the first to demonstrate that therapeutic intervention with a HIF hydroxylase inhibitor ameliorates IBD in disease models. These findings highlight the potential of TRC160334 for its clinical application in the treatment of IBD. PMID:24493931

  12. Effect of β-sodium aescinate on hypoxia-inducible factor-1α expression in rat brain neurons after cardiopulmonary resuscitation

    Institute of Scientific and Technical Information of China (English)

    康健

    2013-01-01

    Objective To investigate the expression of the hypoxia-inducible factor(HIF)-1α in rat brain neuronsand the intervention of β-sodium aescinate after restoration of spontaneous circulation(ROSC).Methods Sixty

  13. Osteogenic Differentiation of Adipose-Derived Stem Cells Is Hypoxia-Inducible Factor-1 Independent

    Science.gov (United States)

    Sahai, Suchit; Williams, Amanda; Skiles, Matthew L.

    2013-01-01

    Tissue engineering is a promising approach to repair critical-size defects in bone. Damage to vasculature at the defect site can create a lower O2 environment compared with healthy bone. Local O2 levels influence stem cell behavior, as O2 is not only a nutrient, but also a signaling molecule. The hypoxia-inducible factor-1 (HIF-1) is a transcription factor that regulates a wide range of O2-related genes and its contribution in bone repair/formation is an important area that can be exploited. In this study, we examined the effect of low O2 environments (1% and 2% O2) on the osteogenic differentiation of adipose-derived stem cells in both two-dimensional (2-D) and three-dimensional (3-D) culture systems. To determine the role of HIF-1 in the differentiation process, an inhibitor was used to block the HIF-1 activity. The samples were examined for osteogenesis markers as measured by quantification of the alkaline phosphatase (ALP) activity, mineral deposition, and expression of osteonectin (ON) and osteopontin (OPN). Results show a downregulation of the osteogenic markers (ALP activity, mineralization, ON, OPN) in both 1% and 2% O2 when compared to 20% O2 in both 2-D and 3-D culture. Vascular endothelial growth factor secretion over 28 days was significantly higher in low O2 environments and HIF-1 inhibition reduced this effect. The inhibition of the HIF-1 activity did not have a significant impact on the expression of the osteogenic markers, suggesting HIF-1-independent inhibition of osteogenic differentiation in hypoxic conditions. PMID:23394201

  14. Expression of hypoxia-inducible factor-1α and erythropoietin at corneal neovascularization in rats

    Directory of Open Access Journals (Sweden)

    Ji-Min Wang

    2014-12-01

    Full Text Available AIM: To describe the expression of hypoxia-inducible factor-1α(HIF-1αand erythropoietin(EPOin rats' corneal and evaluate its potential effect on corneal neovascularization(CNVgrowth. METHODS: The young SD rats(3mowas chosen and randomly divided into 2 groups, which were experimental group and normal control group. CNV model was established by alkali burn, and the length and area of CNV was observed everyday after operation by slit lamp. After that, the expression of HIF-1α and EPO was measured by SABC and RT-PCR methods at 1, 3, 5, 7, and 14d after alkali burn. The data was analyzed by SPSS 20.0. RESULTS: The area of CNV was increasing at 1, 3, 5, 7, and 14d after alkali burn, and the peak point appear at 7d. The growth speed was decreased after 14d. SABC method told us that no HIF-1α and very tiny amount EPO was detected at normal rats' corneal. The expression of the two factors increased at 1d after alkali burn in corneal epithelium and endoderm. The results of RT-PCR showed that a few amounts of HIF-1α and EPO mRNA were detected at normal group. The expression of the two factors was increased at 3d after alkali burn, and the peak value was found at 7d, however, it was decreased at 14d. Statistical difference was found at different time(PCONCLUSION: HIF-1α and EPO is closely related to CNV.

  15. Physiological and Therapeutic Vascular Remodeling Mediated by Hypoxia-Inducible Factor 1

    Science.gov (United States)

    Sarkar, Kakali; Semenza, Gregg L.

    Angiogenesis along with arteriogenesis and vasculogenesis is a fundamental process in ischemic repair in adult animals including humans. Hypoxia-inducible factor 1 (HIF-1) plays a central role in mediating adaptive responses to hypoxia/ischemia by expressing angiogenic cytokines/growth factors and their cognate receptors. Angiogenic growth factors are the homing signal for circulating angiogenic cells (CACs), which are mobilized to peripheral blood from bone marrow, recruited to target tissues, and promote vascularization. Impairment of HIF-1-mediated gene transcription contributes to the impaired vascular responses in peripheral vascular disease that are associated with aging and diabetes. Promoting neovascularization in ischemic tissues is a promising strategy for the treatment of peripheral vascular disease when surgical or catheter-based revascularization is not possible. Intramuscular injection of an adenovirus encoding a constitutively active form of HIF-1α (AdCA5), into the ischemic limb of diabetic mice increases the recovery of limb perfusion and function, rescues the diabetes-associated impairment of CACs, and increases vascularization. Administration of AdCA5 overcomes the effect of aging on recovery of blood flow in middle-aged mice following femoral artery ligation in a mouse model of age-dependent critical limb ischemia. Intramuscular injection of AdCA5 along with intravenous injection of bone-marrow-derived angiogenic cells cultured in the presence of prolyl-4-hydroxylase inhibitor dimethyloxalylglycine, increases blood flow and limb salvage in old mice following femoral artery ligation. HIF-1α gene therapy increases homing of bone-marrow-derived cells, whereas induction of HIF-1 in these cells increases their retention in the ischemic tissue by increasing their adhesion to endothelium leading to synergistic effects of combined therapy on improving blood flow.

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

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    Peng Zhang

    2014-03-01

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

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

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    Joffrey ePelletier

    2012-02-01

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

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

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    Ying Yang

    2017-01-01

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

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

    Science.gov (United States)

    Yang, Ying; Ju, Jieyang; Deng, Min; Wang, Jing; Liu, Hui; Xiong, Li; Zhang, Junjian

    2017-01-17

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

  20. Noninvasive Imaging of Hypoxia-Inducible Factor-1α Gene Therapy for Myocardial Ischemia

    Science.gov (United States)

    Chen, Ian Y.; Gheysens, Olivier; Li, Zongjin; Rasooly, Julia A.; Wang, Qian; Paulmurugan, Ramasamy; Rosenberg, Jarrett; Rodriguez-Porcel, Martin; Willmann, Juergen K.; Wang, David S.; Contag, Christopher H.; Robbins, Robert C.; Wu, Joseph C.

    2013-01-01

    Abstract Hypoxia-inducible factor-1 alpha (HIF-1α) gene therapy holds great promise for the treatment of myocardial ischemia. Both preclinical and clinical evaluations of this therapy are underway and can benefit from a vector strategy that allows noninvasive assessment of HIF-1α expression as an objective measure of gene delivery. We have developed a novel bidirectional plasmid vector (pcTnT-HIF-1α-VP2-TSTA-fluc), which employs the cardiac troponin T (cTnT) promoter in conjunction with a two-step transcriptional amplification (TSTA) system to drive the linked expression of a recombinant HIF-1α gene (HIF-1α-VP2) and the firefly luciferase gene (fluc). The firefly luciferase (FLuc) activity serves as a surrogate for HIF-1α-VP2 expression, and can be noninvasively assessed in mice using bioluminescence imaging after vector delivery. Transfection of cultured HL-1 cardiomyocytes with pcTnT-HIF-1α-VP2-TSTA-fluc led to a strong correlation between FLuc and HIF-1α-dependent vascular endothelial growth factor expression (r2=0.88). Intramyocardial delivery of pcTnT-HIF-1α-VP2-TSTA-fluc into infarcted mouse myocardium led to persistent HIF-1α-VP2 expression for 4 weeks, even though it improved neither CD31+ microvessel density nor echocardiographically determined left ventricular systolic function. These results lend support to recent findings of suboptimal efficacy associated with plasmid-mediated HIF-1α therapy. The imaging techniques developed herein should be useful for further optimizing HIF-1α-VP2 therapy in preclinical models of myocardial ischemia. PMID:23937265

  1. Antagonism of Stem Cell Factor/c-kit Signaling Attenuates Neonatal Chronic Hypoxia-Induced Pulmonary Vascular Remodeling

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    Young, Karen C; Torres, Eneida; Hehre, Dorothy; Wu, Shu; Suguihara, Cleide; Hare, Joshua M.

    2015-01-01

    Background Accumulating evidence suggests that c-kit positive cells are present in the remodeled pulmonary vasculature bed of patients with pulmonary hypertension (PH). Whether stem cell factor (SCF)/ c-kit regulated pathways potentiate pulmonary vascular remodeling is unknown. Here, we tested the hypothesis that attenuated c-kit signaling would decrease chronic hypoxia-induced pulmonary vascular remodeling by decreasing pulmonary vascular cell mitogenesis. Methods Neonatal FVB/NJ mice treated with non-immune IgG (PL), or c-kit neutralizing antibody (ACK2) as well as c-kit mutant mice (WBB6F1- Kit W− v/ +) and their congenic controls, were exposed to normoxia (FiO2=0.21) or hypoxia (FiO2=0.12) for two weeks. Following this exposure, right ventricular systolic pressure (RVSP), right ventricular hypertrophy (RVH), pulmonary vascular cell proliferation and remodeling were evaluated. Results As compared to chronically hypoxic controls, c-kit mutant mice had decreased RVSP, RVH, pulmonary vascular remodeling and proliferation. Consistent with these findings, administration of ACK2 to neonatal mice with chronic hypoxia-induced PH decreased RVSP, RVH, pulmonary vascular cell proliferation and remodeling. This attenuation in PH was accompanied by decreased extracellular signal-regulated protein kinase (ERK) 1/2 activation. Conclusion SCF/c-kit signaling may potentiate chronic hypoxia-induced vascular remodeling by modulating ERK activation. Inhibition of c-kit activity may be a potential strategy to alleviate PH. PMID:26705118

  2. Compound C prevents Hypoxia-Inducible Factor-1α protein stabilization by regulating the cellular oxygen availability via interaction with Mitochondrial Complex I

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    Hagen Thilo

    2011-04-01

    Full Text Available Abstract The transcription factor Hypoxia-Inducible Factor-1α is a master regulator of the cellular response to low oxygen concentration. Compound C, an inhibitor of AMP-activated kinase, has been reported to inhibit hypoxia dependent Hypoxia-Inducible Factor-1α activation via a mechanism that is independent of AMP-activated kinase but dependent on its interaction with the mitochondrial electron transport chain. The objective of this study is to characterize the interaction of Compound C with the mitochondrial electron transport chain and to determine the mechanism through which the drug influences the stability of the Hypoxia-Inducible Factor-1α protein. We found that Compound C functions as an inhibitor of complex I of the mitochondrial electron transport chain as demonstrated by its effect on mitochondrial respiration. It also prevents hypoxia-induced Hypoxia-Inducible Factor-1α stabilization in a dose dependent manner. In addition, Compound C does not have significant effects on reactive oxygen species production from complex I via both forward and reverse electron flux. This study provides evidence that similar to other mitochondrial electron transport chain inhibitors, Compound C regulates Hypoxia-Inducible Factor-1α stability by controlling the cellular oxygen concentration.

  3. Hypoxia-inducible factor-1α expression in the different stages of rat thromboangiitis obliterans.

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    He, T; Qu, B H; Wang, D L; Hu, M

    2015-06-18

    We investigated the expression and effects of hypoxia-inducible factor-1α (HIF-1α) in rat thromboangiitis obliterans (TO). Rats were divided into sham and model groups. The model group was further divided into groups based on observation duration. Lauric acid was injected below an artery clamp to simulate TO in the model group; saline was used in the sham group. Clamps were removed 15 min after injection in both groups, and physiological changes were observed at different times (gross observation and hematoxylin and eosin staining). The animals were killed at various times following the operation and serum and muscle tissues were sampled. For the sham group: the endometrium was relatively intact; medial membrane and epineurium lesions were absent; and blood vessels and surrounding tissues had no inflammatory cell infiltration. For the model group: all subgroups displayed inflammation; large numbers of inflammatory cells were gathered; muscle tissue lost its normal texture and structure; and the internal elastic membrane was integrated. Compared with the preoperative status, HIF-1α expression increased significantly in all subgroups (P < 0.05); there was no change in the sham group. HIF-1α expression in each subgroup was different (F = 14.267, P < 0.05). Femoral artery injection of lauric acid can be used as a rat TO model owing to its simple application and success rate. HIF-1α expression increased in the early stage of TO and gradually decreased with the extension of ischemia time; it may play a leading role in TO development and can be used for diagnosis and cure evaluation.

  4. Synthesis and biological evaluation of diaryl-substituted carboranes as inhibitors of hypoxia inducible factor (HIF)-1 transcriptional activity.

    Science.gov (United States)

    Minegishi, Hidemitsu; Matsukawa, Takuya; Nakamura, Hiroyuki

    2013-02-01

    Diaromatic-substituted ortho- and meta-carboranes were synthesized as mimics of manassantin A. Among the carboranes synthesized, compounds 1 and 2 showed significant inhibition of hypoxia-induced HIF-1 transcriptional activity, with IC(50) values of 3.2 and 2.2 μM, respectively. Compounds 1 and 2 similarly suppressed hypoxia-induced HIF-1α accumulation in a concentration-dependent manner without affecting the expression level of HIF-1α mRNA. The hypoxia-induced accumulation and translocation of HIF-1α into nuclei were not observed in HeLa cells treated with compounds 1 and 2 by immunofluorescence analysis, revealing that the inhibition of hypoxia-induced HIF-1 transcriptional activity is induced by compounds 1 and 2 through a degradation pathway of the HIF-1α protein under hypoxic conditions.

  5. 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

  6. Effects of exposure to a DNA damaging agent on the hypoxia inducible factors in organogenesis stage mouse limbs.

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    Chunwei Huang

    Full Text Available Hypoxia plays a critical role in coordinating cell survival, differentiation and death in normal embryogenesis; during limb pattern formation, hypoxia affects two key processes, chondrogenesis and cell death. Hypoxia promotes chondrocyte differentiation and cartilage matrix synthesis and suppresses terminal differentiation. Depending on the context, hypoxia may induce cell cycle arrest, pro- or anti-apoptotic genes, or autophagy. The response to hypoxia is controlled by hypoxia inducible transcription factors, specifically Hif1a, Hif2a and Hif3a. Under normoxia, the hypoxia-inducible factors respond to a variety of stimuli that include several well established teratogens, such as retinoic acid, heavy metals and hyperglycemia. We hypothesize that teratogenic exposures disrupt limb development by altering the hypoxia signalling pathway. To test this hypothesis, we assessed the effects of a DNA damaging alkylating agent, 4-hydroperoxycyclophosphamide, on the hypoxia inducible factor (HIF transcription factors and on hypoxia in the murine limb bud culture system. 4-Hydroperoxycyclophosphamide exposure increased HIF1 DNA binding activity and HIF1A and HIF2A, but not HIF3A, protein concentrations. HIF1A and HIF2A immunoreactivities were detected in the apical ectodermal ridge and interdigital regions, where cell death sculpts the limb; 4-hydroperoxycyclophosphamide treatment enhanced their immunoreactivities, specifically in these regions. In contrast, hypoxia was localized to areas of chondrogenesis, the cartilaginous anlagen of the developing long bone and phalanges, and was not enhanced by drug exposure. Thus, the exposure of limb buds in vitro to a DNA damaging teratogen triggered a hypoxia signalling response that was associated with cell death. During limb development the HIFs have oxygen-independent functions.

  7. Expression and significance of PTEN, hypoxia-inducible factor-1 alpha in colorectal adenoma and adenocarcinoma

    Institute of Scientific and Technical Information of China (English)

    Ying-An Jiang; Li-Fang Fan; Chong-Qing Jiang; You-Yuan Zhang; He-Sheng Luo; Zhi-Jiao Tang; Dong Xia; Ming Wang

    2003-01-01

    AIM: To investigate the expression and significance of PTEN,hypoxia-inducible factor-1 alpha (HIF-1α), and targeting gene VEGF during colorectal carciogenesis.METHODS: Total 71 cases colorectal neoplasms (9 cases of colorectal adenoma and 62 colorectal adenocarcinoma)were formalin fixed and paraffin-embedded, and all specimens were evaluated for PTEN mRNA, HIF-1α mRNA and VEGF protein expression. PTEN mRNA, HIF-1α mRNA were detected by in situ hybridization. VEGF protein was identified by citrate-microwave SP immunohistochemical method.RESULTS: There were significant differences in PTEN, HIF1α and VEGF expression between colorectal adenomas and colorectal adenocarcinoma (P<0.05). The level of PTEN expression decreased as the pathologic stage increased.Conversely, HIF-1α and VEGF expression increased with the Dukes stage as follows: stage A (0.1029±0.0457:0.1207± 0.0436), stage B (0.1656±0.0329: 0.1572±0.0514),and stage C+D (0.2335±0.0748: 0.2219±0.0803). For PTEN expression, there was a significant difference among Dukes stage A, B, and C+D, and the level of PTEN expression was found to be significant higher in Dukes stage A or B than that of Dukes stage C or D. For HIF-1α expression,there was a significant difference between Dukes stage A and B, and the level of HIF-1α expression was found to be significantly higher in Dukes stage C+D than that of Dukes stage A or B. The VEGF expression had similar results as HIF-1α expression. In colorectal adenocarcinoma,decreased levels of PTEN were significantly associated with increased expression of HIF-1α mRNA (r=-0.36, P<0.05)and VEGF protein (r=-0.48, P<0.05) respectively. The levels of HIF-1 were positively correlated with VEGF expression (r=0.71, P<0.01).CONCLUSION: Loss of PTEN expression and increased levels of HIF-1α and VEGF may play an important role in carcinogenesis and progression of colorectal adenocarcinoma.

  8. Role of hypoxia-inducible factor-1 in transcriptional activation of ceruloplasmin by iron deficiency

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    Mukhopadhyay, C. K.; Mazumder, B.; Fox, P. L.

    2000-01-01

    A role of the copper protein ceruloplasmin (Cp) in iron metabolism is suggested by its ferroxidase activity and by the tissue iron overload in hereditary Cp deficiency patients. In addition, plasma Cp increases markedly in several conditions of anemia, e.g. iron deficiency, hemorrhage, renal failure, sickle cell disease, pregnancy, and inflammation. However, little is known about the cellular and molecular mechanism(s) involved. We have reported that iron chelators increase Cp mRNA expression and protein synthesis in human hepatocarcinoma HepG2 cells. Furthermore, we have shown that the increase in Cp mRNA is due to increased rate of transcription. We here report the results of new studies designed to elucidate the molecular mechanism underlying transcriptional activation of Cp by iron deficiency. The 5'-flanking region of the Cp gene was cloned from a human genomic library. A 4774-base pair segment of the Cp promoter/enhancer driving a luciferase reporter was transfected into HepG2 or Hep3B cells. Iron deficiency or hypoxia increased luciferase activity by 5-10-fold compared with untreated cells. Examination of the sequence showed three pairs of consensus hypoxia-responsive elements (HREs). Deletion and mutation analysis showed that a single HRE was necessary and sufficient for gene activation. The involvement of hypoxia-inducible factor-1 (HIF-1) was shown by gel-shift and supershift experiments that showed HIF-1alpha and HIF-1beta binding to a radiolabeled oligonucleotide containing the Cp promoter HRE. Furthermore, iron deficiency (and hypoxia) did not activate Cp gene expression in Hepa c4 hepatoma cells deficient in HIF-1beta, as shown functionally by the inactivity of a transfected Cp promoter-luciferase construct and by the failure of HIF-1 to bind the Cp HRE in nuclear extracts from these cells. These results are consistent with in vivo findings that iron deficiency increases plasma Cp and provides a molecular mechanism that may help to understand these

  9. TCDD induces the hypoxia-inducible factor (HIF)-1α regulatory pathway in human trophoblastic JAR cells.

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    Liao, Tien-Ling; Chen, Su-Chee; Tzeng, Chii-Reuy; Kao, Shu-Huei

    2014-09-30

    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.

  10. The hypoxia-inducible factor-1α activates ectopic production of fibroblast growth factor 23 in tumor-induced osteomalacia

    Science.gov (United States)

    Zhang, Qian; Doucet, Michele; Tomlinson, Ryan E; Han, Xiaobin; Quarles, L Darryl; Collins, Michael T; Clemens, Thomas L

    2016-01-01

    Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome in which ectopic production of fibroblast growth factor 23 (FGF23) by non-malignant mesenchymal tumors causes phosphate wasting and bone fractures. Recent studies have implicated the hypoxia-inducible factor-1α (HIF-1α) in other phosphate wasting disorders caused by elevated FGF23, including X-linked hypophosphatemic rickets and autosomal dominant hypophosphatemia. Here we provide evidence that HIF-1α mediates aberrant FGF23 in TIO by transcriptionally activating its promoter. Immunohistochemical studies in phosphaturic mesenchymal tumors resected from patients with documented TIO showed that HIF-1α and FGF23 were co-localized in spindle-shaped cells adjacent to blood vessels. Cultured tumor tissue produced high levels of intact FGF23 and demonstrated increased expression of HIF-1α protein. Transfection of MC3T3-E1 and Saos-2 cells with a HIF-1α expression construct induced the activity of a FGF23 reporter construct. Prior treatment of tumor organ cultures with HIF-1α inhibitors decreased HIF-1α and FGF23 protein accumulation and inhibited HIF-1α-induced luciferase reporter activity in transfected cells. Chromatin immunoprecipitation assays confirmed binding to a HIF-1α consensus sequence within the proximal FGF23 promoter, which was eliminated by treatment with a HIF-1α inhibitor. These results show for the first time that HIF-1α is a direct transcriptional activator of FGF23 and suggest that upregulation of HIF-1α activity in TIO contributes to the aberrant FGF23 production in these patients. PMID:27468359

  11. Vascular endothelial growth factor and hypoxia-inducible factor-1α gene polymorphisms and coronary collateral formation in patients with coronary chronic total occlusions

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    Vincent Amoah

    2016-06-01

    Full Text Available Introduction: We evaluated the association between two single nucleotide polymorphisms of the vascular endothelial growth factor gene and one of the hypoxia-inducible factor-1α gene and the degree of coronary collateral formation in patients with a coronary chronic total occlusion. Methods: Totally, 98 patients with symptomatic coronary artery disease and a chronic total occlusion observed during coronary angiography were recruited. Genotyping of two vascular endothelial growth factor promoter single nucleotide polymorphisms (−152G>A and −165C>T and the C1772T single nucleotide polymorphism of hypoxia-inducible factor-1α were performed using polymerase chain reaction and restriction fragment length polymorphism analysis. The presence and extent of collateral vessel filling was scored by blinded observers using the Rentrop grade. Results: We found no association between the vascular endothelial growth factor −152G>A, −165C>T and hypoxia-inducible factor-1α −1772C>T with the presence and filling of coronary collateral vessels. A history of percutaneous coronary intervention and transient ischaemic attack/cerebrovascular accident were associated with the presence of enhanced collateral vessel formation following binary logistic regression analysis. Conclusion: The study findings suggest that coronary collateral formation is not associated with the tested polymorphic variants of vascular endothelial growth factor and hypoxia-inducible factor-1α in patients with symptomatic coronary artery disease and the presence of a chronic total occlusion.

  12. Renal Overexpression of Atrial Natriuretic Peptide and Hypoxia Inducible Factor-1α as Adaptive Response to a High Salt Diet

    OpenAIRE

    Silvana Lorena Della Penna; Gabriel Cao; Andrea Carranza; Elsa Zotta; Susana Gorzalczany; Carolina Susana Cerrudo; Natalia Lucía Rukavina Mikusic; Alicia Correa; Verónica Trida; Jorge Eduardo Toblli; María Inés Rosón; Belisario Enrique Fernández

    2014-01-01

    In the kidney, a high salt intake favors oxidative stress and hypoxia and causes the development of fibrosis. Both atrial natriuretic peptide (ANP) and hypoxia inducible factor (HIF-1α) exert cytoprotective effects. We tested the hypothesis that renal expression of ANP and HIF-1α is involved in a mechanism responding to the oxidative stress produced in the kidneys of rats chronically fed a high sodium diet. Sprague-Dawley rats were fed with a normal salt (0.4% NaCl) (NS) or a high salt (8% Na...

  13. Insulin Promotes Proliferative Vitality and Invasive Capability of Pancreatic Cancer Cells via Hypoxia-inducible Factor 1α Pathway

    Institute of Scientific and Technical Information of China (English)

    汪理; 周伟; 勾善淼; 王统玲; 刘涛; 王春友

    2010-01-01

    This study examined whether insulin-stimulated hypoxia-inducible factor 1α(HIF-1α) expression plays a crucial role in promoting the proliferative vitality and invasive capability in human pancreatic cancer cells.PANC-1 cells were divided into three groups:Control group,insulin group and insulin+YC-1(a pharmacological inhibitor of HIF-1α) group in terms of different treatments.Cells in the insulin group or insulin+YC-1 group were treated with insulin(0.1,1,10 and 100 nmol/L) alone or combined with 3-(5'-hydr...

  14. The role of endogenous nitric oxide and platelet-activating factor in hypoxia-induced intestinal injury in rats.

    Science.gov (United States)

    Caplan, M S; Hedlund, E; Hill, N; MacKendrick, W

    1994-02-01

    Nitric oxide is an endothelium-derived relaxing factor that promotes capillary integrity, inhibits leukocyte adherence and activation, and scavenges oxygen radicals. Because these effects are important in experimental intestinal injury, we studied the role of NO inhibition on hypoxia-induced bowel necrosis in the rat and investigated the interaction between platelet-activating factor (PAF) and NO in this model. Sprague-Dawley rats were treated with either hypoxia, NO synthase inhibition (NG-methyl-L-arginine [LNMA] or NG-nitro-L-arginine methyl ester [L-NAME]), hypoxia+LNMA, hypoxia+LNMA+NO donors, or hypoxia+LNMA+PAF receptor inhibition. Evaluations included blood pressure, superior mesenteric artery blood flow, arterial blood gases, histological intestinal injury, intestinal myeloperoxidase activity, and intestinal PAF activity. We found that hypoxia alone for 90 minutes (10% O2, partial O2 pressure = 45 mm Hg) or LNMA alone had no detrimental effects. However, hypoxia+LNMA together caused hypotension, metabolic acidosis, intestinal injury, increased intestinal myeloperoxidase activity, and elevated intestinal PAF concentrations that were prevented by exogenous L-arginine. Furthermore, the hypotension and intestinal injury was prevented by PAF receptor blockade. We conclude that endogenous NO protects the intestine from hypoxia-induced inflammation and injury, and the balance between local PAF and NO modulates the outcome of hypoxia-stressed intestine.

  15. Hinokitiol protects primary neuron cells against prion peptide-induced toxicity via autophagy flux regulated by hypoxia inducing factor-1.

    Science.gov (United States)

    Moon, Ji-Hong; Lee, Ju-Hee; Lee, You-Jin; Park, Sang-Youel

    2016-05-24

    Prion diseases are fatal neurodegenerative disorders that are derived from structural changes of the native PrPc. Recent studies indicated that hinokitiol induced autophagy known to major function that keeps cells alive under stressful conditions. We investigated whether hinokitiol induces autophagy and attenuates PrP (106-126)-induced neurotoxicity. We observed increase of LC3-II protein level, GFP-LC3 puncta by hinokitiol in neuronal cells. Addition to, electron microscopy showed that hinokitiol enhanced autophagic vacuoles in neuronal cells. We demonstrated that hinokitiol protects against PrP (106-126)-induced neurotoxicity via autophagy by using autophagy inhibitor, wortmannin and 3MA, and ATG5 small interfering RNA (siRNA). We checked hinokitiol activated the hypoxia-inducible factor-1α (HIF-1α) and identified that hinokitiol-induced HIF-1α regulated autophagy. Taken together, this study is the first report demonstrating that hinokitiol protected against prion protein-induced neurotoxicity via autophagy regulated by HIF-1α. We suggest that hinokitiol is a possible therapeutic strategy in neuronal disorders including prion disease.

  16. Flavonoid Compound Icariin Activates Hypoxia Inducible Factor-1α in Chondrocytes and Promotes Articular Cartilage Repair.

    Directory of Open Access Journals (Sweden)

    Pengzhen Wang

    Full Text Available Articular cartilage has poor capability for repair following trauma or degenerative pathology due to avascular property, low cell density and migratory ability. Discovery of novel therapeutic approaches for articular cartilage repair remains a significant clinical need. Hypoxia is a hallmark for cartilage development and pathology. Hypoxia inducible factor-1alpha (HIF-1α has been identified as a key mediator for chondrocytes to response to fluctuations of oxygen availability during cartilage development or repair. This suggests that HIF-1α may serve as a target for modulating chondrocyte functions. In this study, using phenotypic cellular screen assays, we identify that Icariin, an active flavonoid component from Herba Epimedii, activates HIF-1α expression in chondrocytes. We performed systemic in vitro and in vivo analysis to determine the roles of Icariin in regulation of chondrogenesis. Our results show that Icariin significantly increases hypoxia responsive element luciferase reporter activity, which is accompanied by increased accumulation and nuclear translocation of HIF-1α in murine chondrocytes. The phenotype is associated with inhibiting PHD activity through interaction between Icariin and iron ions. The upregulation of HIF-1α mRNA levels in chondrocytes persists during chondrogenic differentiation for 7 and 14 days. Icariin (10-6 M increases the proliferation of chondrocytes or chondroprogenitors examined by MTT, BrdU incorporation or colony formation assays. Icariin enhances chondrogenic marker expression in a micromass culture including Sox9, collagen type 2 (Col2α1 and aggrecan as determined by real-time PCR and promotes extracellular matrix (ECM synthesis indicated by Alcian blue staining. ELISA assays show dramatically increased production of aggrecan and hydroxyproline in Icariin-treated cultures at day 14 of chondrogenic differentiation as compared with the controls. Meanwhile, the expression of chondrocyte catabolic

  17. Acute Cobalt-Induced Lung Injury and the Role of Hypoxia-Inducible Factor 1α in Modulating Inflammation

    Science.gov (United States)

    Saini, Yogesh; Greenwood, Krista K.; Merrill, Christian; Kim, Kyung Y.; Patial, Sonika; Parameswaran, Narayanan; Harkema, Jack R.; LaPres, John J.

    2010-01-01

    Air pollution is a critical factor in the development and exacerbation of pulmonary diseases. Ozone, automobile exhaust, cigarette smoke, and metallic dust are among the potentially harmful pollution components that are linked to disease progression. Transition metals, such as cobalt, have been identified at significant levels in air pollution. Cobalt exerts numerous biological effects, including mimicking hypoxia. Similar to hypoxia, cobalt exposure results in the stabilization of hypoxia-inducible factors (HIFs), a family of proteins that regulate the cellular response to oxygen deficit. HIFs also play an important role in innate immunity and inflammatory processes. To characterize the role of HIF1α, the most ubiquitously expressed HIF, in the early events during cobalt-induced lung inflammation, an inducible lung-specific HIF1α deletion model was employed. Control mice showed classical signs of metal-induced injury following cobalt exposure, including neutrophilic infiltration and induction of Th1 cytokines. In contrast, HIF1α-deficient mice exhibited pronounced eosinophil counts in bronchoalveolar lavage fluid and lung tissue complemented with Th2 cytokine induction. The timing of these results suggests that the loss of epithelial-derived HIF1α alters the lung's innate immune response and biases the tissue toward a Th2-mediated inflammation. PMID:20511350

  18. 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.

  19. El factor inducible por la hipoxia y la actividad física hypoxia-inducible factor and physical activity

    Directory of Open Access Journals (Sweden)

    Juan Camilo Calderón Vélez

    2007-04-01

    Full Text Available Los animales superiores dependen de un adecuado flujo de oxígeno. Los mecanismos involucrados en los procesos de percibir la hipoxia y responder a ella se han ido aclarando, desde hace unos 15 años, con el descubrimiento de las subunidades α y β del factor inducible por la hipoxia (HIF, por su sigla en inglés y de las hidroxilasas involucradas en su regulación. Las especies reactivas de oxígeno (ERO, al parecer, también participan en el proceso de percibir y responder a la hipoxia. Las células musculares podrían ser un modelo útil para estudiar la interrelación hipoxia-ERO-HIF- respuesta celular, con importantes implicaciones básico-clínicas. Sin embargo, apenas comienza el estudio de esta relación en el músculo esquelético. Se revisan en este artículo algunos aspectos interesantes de la investigación en el músculo esquelético y se plantean algunas preguntas e hipótesis que podrían ser evaluadas en este tipo de células. Higher animals depend on an adequate oxygen flux. Mechanisms involved in the process of sensing and responding to hypoxia have become clearer in the last 15 years with the discovery of the y hypoxia-inducible factor (HIF subunits and hydroxylases involved in their regulation. Reactive oxygen species seem to play some role in the process of sensing and responding to hypoxia. Skeletal muscle cells seem to be a suitable model for studying the hypoxia-reactive oxygen species-HIF-cellular response relationship. Its study has important basic and clinic implications. However, the study of this relationship just begins. Some interesting aspects regarding skeletal muscle research are reviewed in this article, and some questions and hypotheses suitable for being evaluated with muscle cells are discussed.

  20. The Expression of Hypoxia Inducible Factor 1-alpha in Lung Cancer and Its Correlation with P53 and VEGF

    Institute of Scientific and Technical Information of China (English)

    张惠兰; 张珍祥; 徐永健; 邢丽华; 刘剑波; 郦俊; 谭庆

    2004-01-01

    To investigate the expression of hypoxia inducible factor 1-alpha (HIF-1α) and its corre lation with P53 and vascular endothelial growth factor (VEGF), immunohistochemical technique was employed to detect the protein expressions of HIF-1α, P53 and VEGF in specimens from 57 patients with lung cancer. The results indicated that the total positive proportion of HIF-1α expression was 63% and the HIF-1α expression was more frequent in bronchiole-alveolar carcinoma (86[作者]) than in other lung cancer. There was a strong association of HIF-1α with VEGF and P53 protein expressions. It is concluded that HIF-1α overexpression is a common event in lung cancer,which may be related to the up-regulation of the angiogenic factor VEGF and oncogene mutant P53 protein.

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

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    Stephan Niebler

    2015-01-01

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

  2. Expression of hypoxia-inducible factors and vascular endothelial growth factor during pregnancy in the feline uterus.

    Science.gov (United States)

    Agaoglu, Ozgecan Korkmaz; Agaoglu, Ali Reha; Guzeloglu, Aydin; Kurar, Ercan; Kayis, Seyit Ali; Ozmen, Ozlem; Schäfer-Somi, Sabine; Aslan, Selim

    2015-07-01

    Hypoxia-inducible factors (HIFs) and vascular endothelial growth factor (VEGF) have critical roles during the development of the fetomaternal unit. The HIFs regulate placentation and vascularization by stimulation of VEGF gene expression. This study aimed to investigate the expression profiles of HIF gene family and VEGF in the cat uterus during pregnancy. Tissue samples of the whole uterine wall were collected after ovariohysterectomy and allocated to the following groups: embryo positive (group 1 [G1], n = 7, 7 days after mating), early pregnancy (group 2 [G2], n = 7, 20 days after mating), mid-pregnancy (group 3 [G3], n = 7, 24 days after mating), late pregnancy (group 4 [G4], n = 7, 30-45 days after mating), and oocyte positive groups (group 5 [G5], n = 7, 7 days after induction of ovulation with GnRH analog). Relative mRNA levels were determined by real-time polymerase chain reaction. As housekeeping gene, glyceraldehyde-3-phosphate dehydrogenase was used. The relative gene expression of HIF1A in G5 was found to be significantly higher than that of other groups (G1, G2, G3, and G4) (P pregnancy and oocyte groups. The expression of HIF3A did not change significantly in any group investigated. These observations suggest that HIFs and VEGF may play a role in the establishment and development of pregnancy.

  3. Targeting angiogenesis via a c-Myc/hypoxia-inducible factor-1alpha-dependent pathway in multiple myeloma.

    Science.gov (United States)

    Zhang, Jing; Sattler, Martin; Tonon, Giovanni; Grabher, Clemens; Lababidi, Samir; Zimmerhackl, Alexander; Raab, Marc S; Vallet, Sonia; Zhou, Yiming; Cartron, Marie-Astrid; Hideshima, Teru; Tai, Yu-Tzu; Chauhan, Dharminder; Anderson, Kenneth C; Podar, Klaus

    2009-06-15

    Bone marrow angiogenesis is associated with multiple myeloma (MM) progression. Here, we report high constitutive hypoxia-inducible factor-1alpha (Hif-1alpha) expression in MM cells, which is associated with oncogenic c-Myc. A drug screen for anti-MM agents that decrease Hif-1alpha and c-Myc levels identified a variety of compounds, including bortezomib, lenalidomide, enzastaurin, and adaphostin. Functionally, based on transient knockdowns and overexpression, our data delineate a c-Myc/Hif-1alpha-dependent pathway mediating vascular endothelial growth factor production and secretion. The antiangiogenic activity of our tool compound, adaphostin, was subsequently shown in a zebrafish model and translated into a preclinical in vitro and in vivo model of MM in the bone marrow milieu. Our data, therefore, identify Hif-1alpha as a novel molecular target in MM and add another facet to anti-MM drug activity.

  4. ATR controls cellular adaptation to hypoxia through positive regulation of hypoxia-inducible factor 1 (HIF-1) expression.

    Science.gov (United States)

    Fallone, F; Britton, S; Nieto, L; Salles, B; Muller, C

    2013-09-12

    Tumor cells adaptation to severe oxygen deprivation (hypoxia) plays a major role in tumor progression. The transcription factor HIF-1 (hypoxia-inducible factor 1), whose α-subunit is stabilized under hypoxic conditions is a key component of this process. Recent studies showed that two members of the phosphoinositide 3-kinase-related kinases (PIKKs) family, ATM (ataxia telangiectasia mutated) and DNA-PK (DNA-dependent protein kinase), regulate the hypoxic-dependent accumulation of HIF-1. These proteins initiate cellular stress responses when DNA damage occurs. In addition, it has been demonstrated that extreme hypoxia induces a replicative stress resulting in regions of single-stranded DNA at stalled replication forks and the activation of ATR (ataxia telangiectasia and Rad3 related protein), another member of the PIKKs family. Here, we show that even less severe hypoxia (0.1% O2) also induces activation of ATR through replicative stress. Importantly, in using either transiently silenced ATR cells, cells expressing an inactive form of ATR or cells exposed to an ATR inhibitor (CGK733), we demonstrate that hypoxic ATR activation positively regulates the key transcription factor HIF-1 independently of the checkpoint kinase Chk1. We show that ATR kinase activity regulates HIF-1α at the translational level and we find that the elements necessary for the regulation of HIF-1α translation are located within the coding region of HIF-1α mRNA. Finally, by using three independent cellular models, we clearly show that the loss of ATR expression and/or kinase activity results in the decrease of HIF-1 DNA binding under hypoxia and consequently affects protein expression levels of two HIF-1 target genes, GLUT-1 and CAIX. Taken together, our data show a new function for ATR in cellular adaptation to hypoxia through regulation of HIF-1α translation. Our work offers new prospect for cancer therapy using ATR inhibitors with the potential to decrease cellular adaptation in hypoxic

  5. Hypoxia-induced mitogenic factor (HIMF/FIZZ1/RELMα in chronic hypoxia- and antigen-mediated pulmonary vascular remodeling

    Directory of Open Access Journals (Sweden)

    Angelini Daniel J

    2013-01-01

    Full Text Available Abstract Background Both chronic hypoxia and allergic inflammation induce vascular remodeling in the lung, but only chronic hypoxia appears to cause PH. We investigate the nature of the vascular remodeling and the expression and role of hypoxia-induced mitogenic factor (HIMF/FIZZ1/RELMα in explaining this differential response. Methods We induced pulmonary vascular remodeling through either chronic hypoxia or antigen sensitization and challenge. Mice were evaluated for markers of PH and pulmonary vascular remodeling throughout the lung vascular bed as well as HIMF expression and genomic analysis of whole lung. Results Chronic hypoxia increased both mean pulmonary artery pressure (mPAP and right ventricular (RV hypertrophy; these changes were associated with increased muscularization and thickening of small pulmonary vessels throughout the lung vascular bed. Allergic inflammation, by contrast, had minimal effect on mPAP and produced no RV hypertrophy. Only peribronchial vessels were significantly thickened, and vessels within the lung periphery did not become muscularized. Genomic analysis revealed that HIMF was the most consistently upregulated gene in the lungs following both chronic hypoxia and antigen challenge. HIMF was upregulated in the airway epithelial and inflammatory cells in both models, but only chronic hypoxia induced HIMF upregulation in vascular tissue. Conclusions The results show that pulmonary vascular remodeling in mice induced by chronic hypoxia or antigen challenge is associated with marked increases in HIMF expression. The lack of HIMF expression in the vasculature of the lung and no vascular remodeling in the peripheral resistance vessels of the lung is likely to account for the failure to develop PH in the allergic inflammation model.

  6. Low Ascorbate Levels Are Associated with Increased Hypoxia-Inducible Factor-1 Activity and an Aggressive Tumor Phenotype in Endometrial Cancer

    NARCIS (Netherlands)

    Kuiper, Caroline; Molenaar, Ilona G. M.; Dachs, Gabi U.; Currie, Margaret J.; Sykes, Peter H.; Vissers, Margreet C. M.

    2010-01-01

    Activation of the transcription factor hypoxia-inducible factor (HIF)-1 allows solid tumors to thrive under conditions of metabolic stress. Because HIF-1 is switched off by hydroxylation reactions that require ascorbate, inadequate intracellular ascorbate levels could contribute to HIF-1 overactivat

  7. Myeloid cell-derived hypoxia-inducible factor attenuates inflammation in unilateral ureteral obstruction-induced kidney injury.

    Science.gov (United States)

    Kobayashi, Hanako; Gilbert, Victoria; Liu, Qingdu; Kapitsinou, Pinelopi P; Unger, Travis L; Rha, Jennifer; Rivella, Stefano; Schlöndorff, Detlef; Haase, Volker H

    2012-05-15

    Renal fibrosis and inflammation are associated with hypoxia, and tissue pO(2) plays a central role in modulating the progression of chronic kidney disease. Key mediators of cellular adaptation to hypoxia are hypoxia-inducible factor (HIF)-1 and -2. In the kidney, they are expressed in a cell type-specific manner; to what degree activation of each homolog modulates renal fibrogenesis and inflammation has not been established. To address this issue, we used Cre-loxP recombination to activate or to delete both Hif-1 and Hif-2 either globally or cell type specifically in myeloid cells. Global activation of Hif suppressed inflammation and fibrogenesis in mice subjected to unilateral ureteral obstruction, whereas activation of Hif in myeloid cells suppressed inflammation only. Suppression of inflammatory cell infiltration was associated with downregulation of CC chemokine receptors in renal macrophages. Conversely, global deletion or myeloid-specific inactivation of Hif promoted inflammation. Furthermore, prolonged hypoxia suppressed the expression of multiple inflammatory molecules in noninjured kidneys. Collectively, we provide experimental evidence that hypoxia and/or myeloid cell-specific HIF activation attenuates renal inflammation associated with chronic kidney injury.

  8. Expression of Hypoxia Inducible Factor-1α and Its Relationship to Apoptosis and Proliferation in Human Laryngeal Squamous Cell Carcinoma

    Institute of Scientific and Technical Information of China (English)

    俞琳琳; 刘洋; 崔永华

    2004-01-01

    To investigate the expression of hypoxia inducible factor-1 alpha (HIF-1α) and its relationship to apoptosis and proliferation in laryngeal squamous cell carcinoma (LSCC), immunohistochemical method was used to detect the expression of HIF-1α and PCNA. Tunnel technique was used to detect in situ cell apoptosis in LSCC. Our results showed that the expression of HIF-1α was related to the clinical stages of cancer and lymph node metastasis (P<0. 05). The relationship between HIF-1α and PCNA was statistically significant (P<0.05) and no relationship was found between HIF-1α and apoptosis (P>0.05) It is concluded that HIF-1α plays a role in the carcinogenesis of laryngeal carcinoma and is correlated with proliferation, but bears no relationship with the apoptosis of tumor cells in LSCC.

  9. Expression and clinical significance of CD73 and hypoxia-inducible factor-1α in gastric carcinoma.

    Science.gov (United States)

    Lu, Xiao-Xia; Chen, Yi-Tian; Feng, Bing; Mao, Xiao-Bei; Yu, Bo; Chu, Xiao-Yuan

    2013-03-28

    To investigate the expression of CD73 and hypoxia-inducible factor-1α (HIF-1α) in human gastric carcinoma, and explore their clinical significance and prognostic value. CD73 and HIF-1α expressions were detected by immunohistochemistry in consecutive sections of tissue samples from 68 gastric carcinoma patients. The peritumor tissues 2 cm away from the tumor were obtained and served as controls. The presence of CD73 and HIF-1α was analyzed by immunohistochemistry using the Envision technique. CD73 and HIF-1α expressions in gastric carcinoma were significantly higher than those in gastric mucosal tissues as control (P gastric carcinoma by both multivariate Cox regression analysis (P = 0.021) and receiver operating characteristic curves (P = 0.001). CD73 expression correlates closely with HIF-1α expression in gastric carcinoma. CD73 could be an independent prognostic indicator for gastric carcinoma.

  10. Pentamidine reduces expression of hypoxia-inducible factor-1α in DU145 and MDA-MB-231 cancer cells.

    Science.gov (United States)

    Jung, Hui-Jung; Suh, Seong-Il; Suh, Min-Ho; Baek, Won-Ki; Park, Jong-Wook

    2011-04-01

    Pentamidine is an aromatic diamine used for the treatment of human protozoa infections. Recently, pentamidine has been reported to exhibit anticancer properties. In this study, we report that pentamidine inhibits expression of hypoxia-inducible factor (HIF)-1α in cancer cells. Pentamidine decreased HIF-1α protein translation and enhanced its protein degradation in DU145 prostate cancer and MDA-MB-231 breast cancer cells. In parallel with reduction of de novo synthesis of HIF-1α, pentamidine was able to suppress global protein translation, an effect accompanied by the reduction of eIF4F complex formation and also the induction of eIF2α phosphorylation. These results show that pentamidine is a potential inhibitor of HIF-1α and its potential as a cancer therapeutic reagent warrants further study.

  11. Hypoxia-inducible factor prolyl hydroxylases as targets for neuroprotection by "antioxidant" metal chelators: From ferroptosis to stroke.

    Science.gov (United States)

    Speer, Rachel E; Karuppagounder, Saravanan S; Basso, Manuela; Sleiman, Sama F; Kumar, Amit; Brand, David; Smirnova, Natalya; Gazaryan, Irina; Khim, Soah J; Ratan, Rajiv R

    2013-09-01

    Neurologic conditions including stroke, Alzheimer disease, Parkinson disease, and Huntington disease are leading causes of death and long-term disability in the United States, and efforts to develop novel therapeutics for these conditions have historically had poor success in translating from bench to bedside. Hypoxia-inducible factor (HIF)-1α mediates a broad, evolutionarily conserved, endogenous adaptive program to hypoxia, and manipulation of components of the HIF pathway is neuroprotective in a number of human neurological diseases and experimental models. In this review, we discuss molecular components of one aspect of hypoxic adaptation in detail and provide perspective on which targets within this pathway seem to be ripest for preventing and repairing neurodegeneration. Further, we highlight the role of HIF prolyl hydroxylases as emerging targets for the salutary effects of metal chelators on ferroptosis in vitro as well in animal models of neurological diseases.

  12. Adipocyte-Specific Hypoxia-Inducible Factor 2α Deficiency Exacerbates Obesity-Induced Brown Adipose Tissue Dysfunction and Metabolic Dysregulation

    OpenAIRE

    García-Martín, Rubén; Alexaki, Vasileia I.; Qin, Nan; Rubín de Celis, María F.; Economopoulou, Matina; Ziogas, Athanasios; Gercken, Bettina; Kotlabova, Klara; Phieler, Julia; Ehrhart-Bornstein, Monika; Bornstein, Stefan R.; Eisenhofer, Graeme; BREIER, GEORG; Blüher, Matthias; Hampe, Jochen

    2016-01-01

    Angiogenesis is a central regulator for white (WAT) and brown (BAT) adipose tissue adaptation in the course of obesity. Here we show that deletion of hypoxia-inducible factor 2α (HIF2α) in adipocytes (by using Fabp4-Cre transgenic mice) but not in myeloid or endothelial cells negatively impacted WAT angiogenesis and promoted WAT inflammation, WAT dysfunction, hepatosteatosis, and systemic insulin resistance in obesity. Importantly, adipocyte HIF2α regulated vascular endothelial growth factor ...

  13. Apigenin ameliorates hypertension-induced cardiac hypertrophy and down-regulates cardiac hypoxia inducible factor-lα in rats.

    Science.gov (United States)

    Zhu, Zeng-Yan; Gao, Tian; Huang, Yan; Xue, Jie; Xie, Mei-Lin

    2016-04-01

    Apigenin is a natural flavonoid compound that can inhibit hypoxia-inducible factor (HIF)-1α expression in cultured tumor cells under hypoxic conditions. Hypertension-induced cardiac hypertrophy is always accompanied by abnormal myocardial glucolipid metabolism due to an increase of HIF-1α. However, whether or not apigenin may ameliorate the cardiac hypertrophy and abnormal myocardial glucolipid metabolism remains unknown. This study aimed to examine the effects of apigenin. Rats with cardiac hypertrophy induced by renovascular hypertension were treated with apigenin 50-100 mg kg(-1) (the doses can be achieved by pharmacological or dietary supplementation for an adult person) by gavage for 4 weeks. The results showed that after treatment with apigenin, the blood pressure, heart weight, heart weight index, cardiomyocyte cross-sectional area, serum angiotensin II, and serum and myocardial free fatty acids were reduced. It is important to note that apigenin decreased the expression level of myocardial HIF-1α protein. Moreover, apigenin simultaneously increased the expression levels of myocardial peroxisome proliferator-activated receptor (PPAR) α, carnitine palmitoyltransferase (CPT)-1, and pyruvate dehydrogenase kinase (PDK)-4 proteins and decreased the expression levels of myocardial PPARγ, glycerol-3-phosphate acyltransferase genes (GPAT), and glucose transporter (GLUT)-4 proteins. These findings demonstrated that apigenin could improve hypertensive cardiac hypertrophy and abnormal myocardial glucolipid metabolism in rats, and its mechanisms might be associated with the down-regulation of myocardial HIF-1α expression and, subsequently increasing the expressions of myocardial PPARα and its target genes CPT-1 and PDK-4, and decreasing the expressions of myocardial PPARγ and its target genes GPAT and GLUT-4.

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

    Directory of Open Access Journals (Sweden)

    Hong-Min Ni

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

  15. Emerging roles of hypoxia-inducible factors and reactive oxygen species in cancer and pluripotent stem cells

    Directory of Open Access Journals (Sweden)

    Shigeo Saito

    2015-06-01

    Full Text Available Eukaryotic organisms require oxygen homeostasis to maintain proper cellular function for survival. During conditions of low oxygen tension (hypoxia, cells activate the transcription of genes that induce an adaptive response, which supplies oxygen to tissues. Hypoxia and hypoxia-inducible factors (HIFs may contribute to the maintenance of putative cancer stem cells, which can continue self-renewal indefinitely and express stemness genes in hypoxic stress environments (stem cell niches. Reactive oxygen species (ROS have long been recognized as toxic by-products of aerobic metabolism that are harmful to living cells, leading to DNA damage, senescence, or cell death. HIFs may promote a cancer stem cell state, whereas the loss of HIFs induces the production of cellular ROS and activation of proteins p53 and p16Ink4a, which lead to tumor cell death and senescence. ROS seem to inhibit HIF regulation in cancer cells. By contrast, controversial data have suggested that hypoxia increases the generation of ROS, which prevents hydroxylation of HIF proteins by inducing their transcription as negative feedback. Moreover, hypoxic conditions enhance the generation of induced pluripotent stem cells (iPSCs. During reprogramming of somatic cells into a PSC state, cells attain a metabolic state typically observed in embryonic stem cells (ESCs. ESCs and iPSCs share similar bioenergetic metabolisms, including decreased mitochondrial number and activity, and induced anaerobic glycolysis. This review discusses the current knowledge regarding the emerging roles of ROS homeostasis in cellular reprogramming and the implications of hypoxic regulation in cancer development.

  16. Lysyl oxidase is essential for hypoxia-induced metastasis

    DEFF Research Database (Denmark)

    Erler, Janine Terra; Bennewith, Kevin L; Nicolau, Monica

    2006-01-01

    role in tumorigenesis seems dependent on cellular location, cell type and transformation status. Here we show that LOX expression is regulated by hypoxia-inducible factor (HIF) and is associated with hypoxia in human breast and head and neck tumours. Patients with high LOX-expressing tumours have poor...

  17. Hypoxia-inducible factor-1 α/platelet derived growth factor axis in HIV-associated pulmonary vascular remodeling

    Directory of Open Access Journals (Sweden)

    Bartolome Sonja

    2011-08-01

    Full Text Available Abstract Background Human immunodeficiency virus (HIV infected patients are at increased risk for the development of pulmonary arterial hypertension (PAH. Recent reports have demonstrated that HIV associated viral proteins induce reactive oxygen species (ROS with resultant endothelial cell dysfunction and related vascular injury. In this study, we explored the impact of HIV protein induced oxidative stress on production of hypoxia inducible factor (HIF-1α and platelet-derived growth factor (PDGF, critical mediators implicated in the pathogenesis of HIV-PAH. Methods The lungs from 4-5 months old HIV-1 transgenic (Tg rats were assessed for the presence of pulmonary vascular remodeling and HIF-1α/PDGF-BB expression in comparison with wild type controls. Human primary pulmonary arterial endothelial cells (HPAEC were treated with HIV-associated proteins in the presence or absence of pretreatment with antioxidants, for 24 hrs followed by estimation of ROS levels and western blot analysis of HIF-1α or PDGF-BB. Results HIV-Tg rats, a model with marked viral protein induced vascular oxidative stress in the absence of active HIV-1 replication demonstrated significant medial thickening of pulmonary vessels and increased right ventricular mass compared to wild-type controls, with increased expression of HIF-1α and PDGF-BB in HIV-Tg rats. The up-regulation of both HIF-1α and PDGF-B chain mRNA in each HIV-Tg rat was directly correlated with an increase in right ventricular/left ventricular+septum ratio. Supporting our in-vivo findings, HPAECs treated with HIV-proteins: Tat and gp120, demonstrated increased ROS and parallel increase of PDGF-BB expression with the maximum induction observed on treatment with R5 type gp-120CM. Pre-treatment of endothelial cells with antioxidants or transfection of cells with HIF-1α small interfering RNA resulted in abrogation of gp-120CM mediated induction of PDGF-BB, therefore, confirming that ROS generation and

  18. 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

  19. Hypoxic regulation of lactate dehydrogenase A. Interaction between hypoxia-inducible factor 1 and cAMP response elements.

    Science.gov (United States)

    Firth, J D; Ebert, B L; Ratcliffe, P J

    1995-09-08

    The oxygen-regulated control system responsible for the induction of erythropoietin (Epo) by hypoxia is present in most (if not all) cells and operates on other genes, including those involved in energy metabolism. To understand the organization of cis-acting sequences that are responsible for oxygen-regulated gene expression, we have studied the 5' flanking region of the mouse gene encoding the hypoxically inducible enzyme lactate dehydrogenase A (LDH). Deletional and mutational analysis of the function of mouse LDH-reporter fusion gene constructs in transient transfection assays defined three domains, between -41 and -84 base pairs upstream of the transcription initiation site, which were crucial for oxygen-regulated expression. The most important of these, although not capable of driving hypoxic induction in isolation, had the consensus of a hypoxia-inducible factor 1 (HIF-1) site, and cross-competed for the binding of HIF-1 with functionally active Epo and phosphoglycerate kinase-1 sequences. The second domain was positioned close to the HIF-1 site, in an analogous position to one of the critical regions in the Epo 3' hypoxic enhancer. The third domain had the motif of a cAMP response element (CRE). Activation of cAMP by forskolin had no effect on the level of LDH mRNA in normoxia, but produced a magnified response to hypoxia that was dependent upon the integrity of the CRE, indicating an interaction between inducible factors binding the HIF-1 and CRE sites.

  20. Distinctive expression patterns of hypoxia-inducible factor-1α and endothelial nitric oxide synthase following hypergravity exposure

    Science.gov (United States)

    Yoon, Gun; Oh, Choong Sik; Kim, Hyun-Soo

    2016-01-01

    This study was designed to examine the expression of hypoxia-inducible factor-1α (HIF-1α) and the level and activity of endothelial nitric oxide synthase (eNOS) in the hearts and livers of mice exposed to hypergravity. Hypergravity-induced hypoxia and the subsequent post-exposure reoxygenation significantly increased cardiac HIF-1α levels. Furthermore, the levels and activity of cardiac eNOS also showed significant increase immediately following hypergravity exposure and during the reoxygenation period. In contrast, the expression of phosphorylated Akt (p-Akt) and phosphorylated extracellular signal-regulated kinase (p-ERK) showed significant elevation only during the reoxygenation period. These data raise the possibility that the increase in cardiac HIF-1α expression induced by reoxygenation involves a cascade of signaling events, including activation of the Akt and ERK pathways. In the liver, HIF-1α expression was significantly increased immediately after hypergravity exposure, indicating that hypergravity exposure to causes hepatocellular hypoxia. The hypergravity-exposed livers showed significantly higher eNOS immunoreactivity than did those of control mice. Consistent with these results, significant increases in eNOS activity and nitrate/nitrite levels were also observed. These findings suggest that hypergravity-induced hypoxia plays a significant role in the upregulation of hepatic eNOS. PMID:27191892

  1. The involvement of hypoxia-inducible factor 1 alpha in Toll-like receptor 7/8-mediated inflammatory response

    Institute of Scientific and Technical Information of China (English)

    Sally A Nicholas; Vadim V Sumbayev

    2009-01-01

    Toll-like receptors (TLRs) 7 and 8 are crucial in host defence against single-stranded RNA (ssRNA) viruses. Such viruses cause severe illnesses, which remain a serious medical burden in both industrialised and developing countries. TLR7/8 downstream signaling leads to a dramatic cellular stress associated with energy consumption. However, the molecular mechanisms of cell survival and adaptation to TLR7/8-induced stress, which give the cells an opportunity to initiate proper inflammatory reactions, are not clear at all. Here we report for the first time that ligand-induced ac-tivation of TLR7/8 leads to the accumulation of hypoxia-inducible factor 1 alpha (HIF-1α) protein in THP-1 human myeloid macrophages via redox-and reactive nitrogen species-dependent mechanisms. MAP kinases and phosphoi-nositol-3K are not involved in TLR7/8-mediated HIF-1α accumulation. Experiments with HIF-la knockdown THP-1 cells have clearly demonstrated that HIF-1α is important for the protection of these cells against TLR7/8-induced depletion of ATP. Thus, HIF-1α might support both cell survival and the production of pro-inflammatory cytokines upon TLR7/8 activation.

  2. Hypoxia-induced angiogenesis: good and evil.

    Science.gov (United States)

    Krock, Bryan L; Skuli, Nicolas; Simon, M Celeste

    2011-12-01

    The vascular network delivers oxygen (O(2)) and nutrients to all cells within the body. It is therefore not surprising that O(2) availability serves as a primary regulator of this complex organ. Most transcriptional responses to low O(2) are mediated by hypoxia-inducible factors (HIFs), highly conserved transcription factors that control the expression of numerous angiogenic, metabolic, and cell cycle genes. Accordingly, the HIF pathway is currently viewed as a master regulator of angiogenesis. HIF modulation could provide therapeutic benefit for a wide array of pathologies, including cancer, ischemic heart disease, peripheral artery disease, wound healing, and neovascular eye diseases. Hypoxia promotes vessel growth by upregulating multiple pro-angiogenic pathways that mediate key aspects of endothelial, stromal, and vascular support cell biology. Interestingly, recent studies show that hypoxia influences additional aspects of angiogenesis, including vessel patterning, maturation, and function. Through extensive research, the integral role of hypoxia and HIF signaling in human disease is becoming increasingly clear. Consequently, a thorough understanding of how hypoxia regulates angiogenesis through an ever-expanding number of pathways in multiple cell types will be essential for the identification of new therapeutic targets and modalities.

  3. Steroid receptor coactivator-3 regulates glucose metabolism in bladder cancer cells through coactivation of hypoxia inducible factor 1α.

    Science.gov (United States)

    Zhao, Wei; Chang, Cunjie; Cui, Yangyan; Zhao, Xiaozhi; Yang, Jun; Shen, Lan; Zhou, Ji; Hou, Zhibo; Zhang, Zhen; Ye, Changxiao; Hasenmayer, Donald; Perkins, Robert; Huang, Xiaojing; Yao, Xin; Yu, Like; Huang, Ruimin; Zhang, Dianzheng; Guo, Hongqian; Yan, Jun

    2014-04-18

    Cancer cell proliferation is a metabolically demanding process, requiring high glycolysis, which is known as "Warburg effect," to support anabolic growth. Steroid receptor coactivator-3 (SRC-3), a steroid receptor coactivator, is overexpressed and/or amplified in multiple cancer types, including non-steroid targeted cancers, such as urinary bladder cancer (UBC). However, whether SRC-3 regulates the metabolic reprogramming for cancer cell growth is unknown. Here, we reported that overexpression of SRC-3 accelerated UBC cell growth, accompanied by the increased expression of genes involved in glycolysis. Knockdown of SRC-3 reduced the UBC cell glycolytic rate under hypoxia, decreased tumor growth in nude mice, with reduction of proliferating cell nuclear antigen and lactate dehydrogenase expression levels. We further revealed that SRC-3 could interact with hypoxia inducible factor 1α (HIF1α), which is a key transcription factor required for glycolysis, and coactivate its transcriptional activity. SRC-3 was recruited to the promoters of HIF1α-target genes, such as glut1 and pgk1. The positive correlation of expression levels between SRC-3 and Glut1 proteins was demonstrated in human UBC patient samples. Inhibition of glycolysis through targeting HK2 or LDHA decelerated SRC-3 overexpression-induced cell growth. In summary, overexpression of SRC-3 promoted glycolysis in bladder cancer cells through HIF1α to facilitate tumorigenesis, which may be an intriguing drug target for bladder cancer therapy.

  4. Intestine-specific Disruption of Hypoxia-inducible Factor (HIF)-2α Improves Anemia in Sickle Cell Disease*

    Science.gov (United States)

    Das, Nupur; Xie, Liwei; Ramakrishnan, Sadeesh K.; Campbell, Andrew; Rivella, Stefano; Shah, Yatrik M.

    2015-01-01

    Sickle cell disease (SCD) is caused by genetic defects in the β-globin chain. SCD is a frequently inherited blood disorder, and sickle cell anemia is a common type of hemoglobinopathy. During anemia, the hypoxic response via the transcription factor hypoxia-inducible factor (HIF)-2α is highly activated in the intestine and is essential in iron absorption. Intestinal disruption of HIF-2α protects against tissue iron accumulation in iron overload anemias. However, the role of intestinal HIF-2α in regulating anemia in SCD is currently not known. Here we show that in mouse models of SCD, disruption of intestinal HIF-2α significantly decreased tissue iron accumulation. This was attributed to a decrease in intestinal iron absorptive genes, which were highly induced in a mouse model of SCD. Interestingly, disruption of intestinal HIF-2α led to a robust improvement in anemia with an increase in RBC, hemoglobin, and hematocrit. This was attributed to improvement in RBC survival, hemolysis, and insufficient erythropoiesis, which is evident from a significant decrease in serum bilirubin, reticulocyte counts, and serum erythropoietin following intestinal HIF-2α disruption. These data suggest that targeting intestinal HIF-2α has a significant therapeutic potential in SCD pathophysiology. PMID:26296885

  5. Intestine-specific Disruption of Hypoxia-inducible Factor (HIF)-2α Improves Anemia in Sickle Cell Disease.

    Science.gov (United States)

    Das, Nupur; Xie, Liwei; Ramakrishnan, Sadeesh K; Campbell, Andrew; Rivella, Stefano; Shah, Yatrik M

    2015-09-25

    Sickle cell disease (SCD) is caused by genetic defects in the β-globin chain. SCD is a frequently inherited blood disorder, and sickle cell anemia is a common type of hemoglobinopathy. During anemia, the hypoxic response via the transcription factor hypoxia-inducible factor (HIF)-2α is highly activated in the intestine and is essential in iron absorption. Intestinal disruption of HIF-2α protects against tissue iron accumulation in iron overload anemias. However, the role of intestinal HIF-2α in regulating anemia in SCD is currently not known. Here we show that in mouse models of SCD, disruption of intestinal HIF-2α significantly decreased tissue iron accumulation. This was attributed to a decrease in intestinal iron absorptive genes, which were highly induced in a mouse model of SCD. Interestingly, disruption of intestinal HIF-2α led to a robust improvement in anemia with an increase in RBC, hemoglobin, and hematocrit. This was attributed to improvement in RBC survival, hemolysis, and insufficient erythropoiesis, which is evident from a significant decrease in serum bilirubin, reticulocyte counts, and serum erythropoietin following intestinal HIF-2α disruption. These data suggest that targeting intestinal HIF-2α has a significant therapeutic potential in SCD pathophysiology.

  6. Ascent to altitude as a weight loss method: the good and bad of hypoxia inducible factor activation.

    Science.gov (United States)

    Palmer, Biff F; Clegg, Deborah J

    2014-02-01

    Given the epidemic of obesity worldwide there is a need for more novel and effective weight loss methods. Altitude is well known to be associated with weight loss and has actually been used as a method of weight reduction in obese subjects. This review demonstrates the critical role of hypoxia inducible factor (HIF) in bringing about reductions in appetite and increases in energy expenditure characteristic of hypobaric hypoxia A MEDLINE search of English language articles through February 2013 identified publications associating altitude or hypobaric hypoxia with key words to include HIF, weight loss, appetite, basal metabolic rate, leptin, cellular energetics, and obesity. The data from these articles were synthesized to formulate a unique and novel mechanism by which HIF activation leads to alterations in appetite, basal metabolic rate, and reductions in body adiposity. A synthesis of previously published literature revealed mechanisms by which altitude induces activation of HIF, thereby suggesting this transcription factor regulates changes in cellular metabolism/energetics, activation of the central nervous system, as well as peripheral pathways leading to reductions in food intake and increases in energy expenditure. Here a unifying hypothesis is present suggesting that activation of HIF under conditions of altitude potentially leads to metabolic benefits that are dose dependent, gender and genetic specific, and results in adverse effects if the exposure is extreme. Copyright © 2013 The Obesity Society.

  7. Hypoxia-inducing factors as master regulators of stemness properties and altered metabolism of cancer- and metastasis-initiating cells

    Science.gov (United States)

    Mimeault, Murielle; Batra, Surinder K

    2013-01-01

    Accumulating lines of experimental evidence have revealed that hypoxia-inducible factors, HIF-1α and HIF-2α, are key regulators of the adaptation of cancer- and metastasis-initiating cells and their differentiated progenies to oxygen and nutrient deprivation during cancer progression under normoxic and hypoxic conditions. Particularly, the sustained stimulation of epidermal growth factor receptor (EGFR), insulin-like growth factor-1 receptor (IGF-1R), stem cell factor (SCF) receptor KIT, transforming growth factor-β receptors (TGF-βRs) and Notch and their downstream signalling elements such as phosphatidylinositol 3′-kinase (PI3K)/Akt/molecular target of rapamycin (mTOR) may lead to an enhanced activity of HIFs. Moreover, the up-regulation of HIFs in cancer cells may also occur in the hypoxic intratumoral regions formed within primary and secondary neoplasms as well as in leukaemic cells and metastatic prostate and breast cancer cells homing in the hypoxic endosteal niche of bone marrow. The activated HIFs may induce the expression of numerous gene products such as induced pluripotency-associated transcription factors (Oct-3/4, Nanog and Sox-2), glycolysis- and epithelial-mesenchymal transition (EMT) programme-associated molecules, including CXC chemokine receptor 4 (CXCR4), snail and twist, microRNAs and angiogenic factors such as vascular endothelial growth factor (VEGF). These gene products in turn can play critical roles for high self-renewal ability, survival, altered energy metabolism, invasion and metastases of cancer cells, angiogenic switch and treatment resistance. Consequently, the targeting of HIF signalling network and altered metabolic pathways represents new promising strategies to eradicate the total mass of cancer cells and improve the efficacy of current therapies against aggressive and metastatic cancers and prevent disease relapse. PMID:23301832

  8. Wheatgrass extract inhibits hypoxia-inducible factor-1-mediated epithelial-mesenchymal transition in A549 cells

    Science.gov (United States)

    Do, Nam Yong; Shin, Hyun-Jae

    2017-01-01

    BACKGROUND/OBJECTIVES Epithelial-mesenchymal transition (EMT) is involved in not only cancer development and metastasis but also non-cancerous conditions. Hypoxia is one of the proposed critical factors contributing to formation of chronic rhinosinusitis or nasal polyposis. Wheatgrass (Triticum aestivum) has antioxidant, anti-aging, and anti-inflammatory effects. In this study, we analyzed whether wheatgrass has an inhibitory effect on the EMT process in airway epithelial cells. MATERIALS/METHODS A549 human lung adenocarcinoma cells were incubated in hypoxic conditions (CO2 5%/O2 1%) for 24 h in the presence of different concentrations of wheatgrass extract (50, 75, 100, and 150 µg/mL) and changes in expression of epithelial or mesenchymal markers were evaluated by immunoblotting and immunofluorescence. Accordingly, associated EMT-related transcriptional factors, Snail and Smad, were also evaluated. RESULTS Hypoxia increased expression of N-cadherin and reduced expression of E-cadherin. Mechanistically, E-cadherin levels were recovered during hypoxia by silencing hypoxia inducible factor (HIF)-1α or administering wheatgrass extract. Wheatgrass inhibited the hypoxia-mediated EMT by reducing the expression of phosphorylated Smad3 (pSmad3) and Snail. It suppressed the hypoxia-mediated EMT processes of airway epithelial cells via HIF-1α and the pSmad3 signaling pathway. CONCLUSION These results suggest that wheatgrass has potential as a therapeutic or supplementary agent for HIF-1-related diseases.

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

    Science.gov (United States)

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

    2015-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Stefania Merighi

    2005-10-01

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

  11. Hypoxia-Inducible Factor-1alpha Suppressing Apoptosis and Increasing Tolerance of Lung Cancer Cells to Chemotherapy

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wanguang; ZHANG Huilan

    2006-01-01

    In order to construct plasmid of hypoxia-inducible factor-lalpha (HIF-1α), and transfect into human lung cancer cells A549, the change in sensitivity of lung cancer cells A549 to chemotherapy was observed. HIF-1α mRNA structure region was amplified by RT-PCR and inserted into plasmid pcDNA3. The expression plasmid pcDNA3/HIF-1α was transfected into A549 with LipofectAMINETM2000. The expression of HIF-1α protein was detected by Western blot. After A549 cells were transfected with HIF-1α prior to addition of 5-Fu, the growth activity was measured by growth curve, apoptosis was detected by flow cytometry at 48 h, and the levels of caspase3 and MDR-1 were determined by Western blot. The results showed that the constructed expression plasmid was analyzed with restriction enzymes and gel electrophoresis. Two DNA lanes at 2.55 kb and 5.4 kb respectively were found, which were consistent with that expected. The growth rate in 5-Fu group was significantly inhibited, and the apoptosis index and caspase3 activity were increased significantly as compared with control group. After HIF-1 α being transfected into A549, the activity of MDR-1 was increased and the effect of 5-Fu was weakened. In conclusion, HIF-1α can promote chemoresistance by increasing the activation of MDR1 and suppressing apoptosis during lung cancer cells A549 induced with 5-Fu.

  12. Hypoxia-inducible Factor Prolyl 4-Hydroxylase Inhibition A TARGET FOR NEUROPROTECTION IN THE CENTRAL NERVOUS SYSTEM*

    Science.gov (United States)

    Siddiq, Ambreena; Ayoub, Issam A.; Chavez, Juan C.; Aminova, Leila; Shah, Sapan; LaManna, Joseph C.; Patton, Stephanie M.; Connor, James R.; Cherny, Robert A.; Volitakis, Irene; Bush, Ashley I.; Langsetmo, Ingrid; Seeley, Todd; Gunzler, Volkmar; Ratan, Rajiv R.

    2008-01-01

    Hypoxia-inducible factor (HIF) prolyl 4-hydroxylases are a family of iron- and 2-oxoglutarate-dependent dioxygenases that negatively regulate the stability of several proteins that have established roles in adaptation to hypoxic or oxidative stress. These proteins include the transcriptional activators HIF-1α and HIF-2α. The ability of the inhibitors of HIF prolyl 4-hydroxylases to stabilize proteins involved in adaptation in neurons and to prevent neuronal injury remains unclear. We reported that structurally diverse low molecular weight or peptide inhibitors of the HIF prolyl 4-hydroxylases stabilize HIF-1α and up-regulate HIF-dependent target genes (e.g. enolase, p21waf1/cip1, vascular endothelial growth factor, or erythropoietin) in embryonic cortical neurons in vitro or in adult rat brains in vivo. We also showed that structurally diverse HIF prolyl 4-hydroxylase inhibitors prevent oxidative death in vitro and ischemic injury in vivo. Taken together these findings identified low molecular weight and peptide HIF prolyl 4-hydroxylase inhibitors as novel neurological therapeutics for stroke as well as other diseases associated with oxidative stress. PMID:16227210

  13. Detection of the onset of ischemia and carcinogenesis by hypoxia-inducible transcription factor-based in vivo bioluminescence imaging.

    Directory of Open Access Journals (Sweden)

    Tetsuya Kadonosono

    Full Text Available An animal model for the early detection of common fatal diseases such as ischemic diseases and cancer is desirable for the development of new drugs and treatment strategies. Hypoxia-inducible factor 1 (HIF-1 is a transcription factor that regulates oxygen homeostasis and plays key roles in a number of diseases, including cancer. Here, we established transgenic (Tg mice that carry HRE/ODD-luciferase (HOL gene, which generates bioluminescence in an HIF-1-dependent manner and was successfully used in this study to monitor HIF-1 activity in ischemic tissues. To monitor carcinogenesis in vivo, we mated HOL mice with rasH2 Tg mice, which are highly sensitive to carcinogens and are used for short-term carcinogenicity assessments. After rasH2-HOL Tg mice were treated with N-methyl-N-nitrosourea, bioluminescence was detected noninvasively as early as 9 weeks in tissues that contained papillomas and malignant lesions. These results suggest that the Tg mouse lines we established hold significant potential for monitoring the early onset of both ischemia and carcinogenesis and that these lines will be useful for screening chemicals for carcinogenic potential.

  14. The Hypoxia-Inducible Factor Pathway, Prolyl Hydroxylase Domain Protein Inhibitors, and Their Roles in Bone Repair and Regeneration

    Directory of Open Access Journals (Sweden)

    Lihong Fan

    2014-01-01

    Full Text Available Hypoxia-inducible factors (HIFs are oxygen-dependent transcriptional activators that play crucial roles in angiogenesis, erythropoiesis, energy metabolism, and cell fate decisions. The group of enzymes that can catalyse the hydroxylation reaction of HIF-1 is prolyl hydroxylase domain proteins (PHDs. PHD inhibitors (PHIs activate the HIF pathway by preventing degradation of HIF-α via inhibiting PHDs. Osteogenesis and angiogenesis are tightly coupled during bone repair and regeneration. Numerous studies suggest that HIFs and their target gene, vascular endothelial growth factor (VEGF, are critical regulators of angiogenic-osteogenic coupling. In this brief perspective, we review current studies about the HIF pathway and its role in bone repair and regeneration, as well as the cellular and molecular mechanisms involved. Additionally, we briefly discuss the therapeutic manipulation of HIFs and VEGF in bone repair and bone tumours. This review will expand our knowledge of biology of HIFs, PHDs, PHD inhibitors, and bone regeneration, and it may also aid the design of novel therapies for accelerating bone repair and regeneration or inhibiting bone tumours.

  15. Effect of Hachimijiogan against Renal Dysfunction and Involvement of Hypoxia-Inducible Factor-1α in the Remnant Kidney Model

    Directory of Open Access Journals (Sweden)

    Hiroshi Oka

    2011-01-01

    Full Text Available In chronic renal failure, hypoxia of renal tissue is thought to be the common final pathway leading to end-stage renal failure. In this study the effects of hachimijiogan, a Kampo formula, were studied with respect to hypoxia-inducible factor (HIF. Using remnant kidney rats, we studied the effects of hachimijiogan on renal function in comparison with angiotensin II receptor blocker. The result showed that oral administration of hachimijiogan for seven days suppressed urinary protein excretion and urinary 8-OHdG, a marker of antioxidant activity, equally as well as oral administration of candesartan cilexetil. In contrast, the protein volume of HIF-1α in the renal cortex was not increased in the candesartan cilexetil group, but that in the hachimijiogan group was increased. In immunohistochemical studies as well, the expression of HIF-1α of the high-dose hachimijiogan group increased compared to that of the control group. Vascular endothelial growth factor and glucose transporter 1, target genes of HIF-1α, were also increased in the hachimijiogan group. These results suggest that hachimijiogan produces a protective effect by a mechanism different from that of candesartan cilexetil.

  16. Regulation of the Drosophila Hypoxia-Inducible Factor α Sima by CRM1-Dependent Nuclear Export ▿

    Science.gov (United States)

    Romero, Nuria M.; Irisarri, Maximiliano; Roth, Peggy; Cauerhff, Ana; Samakovlis, Christos; Wappner, Pablo

    2008-01-01

    Hypoxia-inducible factor α (HIF-α) proteins are regulated by oxygen levels through several different mechanisms that include protein stability, transcriptional coactivator recruitment, and subcellular localization. It was previously reported that these transcription factors are mainly nuclear in hypoxia and cytoplasmic in normoxia, but so far the molecular basis of this regulation is unclear. We show here that the Drosophila melanogaster HIF-α protein Sima shuttles continuously between the nucleus and the cytoplasm. We identified the relevant nuclear localization signal and two functional nuclear export signals (NESs). These NESs are in the Sima basic helix-loop-helix (bHLH) domain and promote CRM1-dependent nuclear export. Site-directed mutagenesis of either NES provoked Sima nuclear retention and increased transcriptional activity, suggesting that nuclear export contributes to Sima regulation. The identified NESs are conserved and probably functional in the bHLH domains of several bHLH-PAS proteins. We propose that rapid nuclear export of Sima regulates the duration of cellular responses to hypoxia. PMID:18332128

  17. Time-dependent stabilization of hypoxia inducible factor-1α by different intracellular sources of reactive oxygen species.

    Directory of Open Access Journals (Sweden)

    Maura Calvani

    Full Text Available Intratumoral hypoxia is a major obstacle in the development of effective cancer chemotherapy, decreasing the efficacy of anti-neoplastic drugs in several solid tumours. The hypoxic environment, through its master regulator hypoxia inducible factor-1 (HIF-1, is able to maintain an anti-apoptotic potential through activation of critical genes associated with drug resistance. Besides affecting metabolism and motility of tumour cells, hypoxia also paradoxically increases production of reactive oxygen species (ROS, which contribute to stabilize HIF-1 through a redox-mediated inhibition of its proteolysis. Here we reported that 1% O(2 hypoxia increases the resistance of human metastatic melanoma cells to conventional chemotherapy with etoposide, and that the increase in chemoresistance strongly depends on ROS delivery due to hypoxia. We reported a biphasic redox-dependent role of HIF-1, involving mitochondrial complex III and NADPH oxidase as oxidants sources, synergising in enhancing survival to chemotherapy. The feed-forward loop engaged by hypoxia involves first an HIF-1-dependent vascular endothelial growth factor-A (VEGF-A autocrine production and, in the later phase, activation of NADPH oxidase from VEGF/VEGFR2 interaction, finally leading to a further redox-dependent long lasting stabilization of HIF-1. We therefore identified a redox-dependent circuitry linking hypoxia-driven ROS to VEGF-A secretion and to enhanced melanoma cell survival to etoposide chemotherapy.

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

    Science.gov (United States)

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

    2015-07-01

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

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

    Science.gov (United States)

    Li, Jie; Zhang, Chao; Jiang, Hongchuan; Cheng, Jiao

    2015-01-01

    Hypoxia-inducible factor-1 (HIF-1) is a master regulator of the transcriptional response to hypoxia. HIF-1α is one of the most compelling anticancer targets. Andrographolide (Andro) was newly identified to inhibit HIF-1 in T47D cells (a half maximal effective concentration [EC50] of 1.03×10−7 mol/L), by a dual-luciferase reporter assay. It suppressed HIF-1α protein and gene accumulation, which was dependent on the inhibition of upstream phosphatidylinositol 3-kinase (PI3K)/AKT pathway. It also abrogated the expression of HIF-1 target vascular endothelial growth factor (VEGF) gene and protein. Further, Andro inhibited T47D and MDA-MB-231 cell proliferation and colony formation. In addition, it exhibited significant in vivo efficacy and antitumor potential against the MDA-MB-231 xenograft in nude mice. In conclusion, these results highlighted the potential effects of Andro, which inhibits HIF-1, and hence may be developed as an antitumor agent for breast cancer therapy in future. PMID:25709476

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

    Directory of Open Access Journals (Sweden)

    Li J

    2015-02-01

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

  1. Correlation between the Expression of Aquaporin 1 and Hypoxia-inducible Factor 1 in Breast Cancer Tissues

    Institute of Scientific and Technical Information of China (English)

    Tiejun YIN; Shiying YU; Liang XIAO; Jun ZHANG; Chong LIU; Yunping LU; Chengping LIU

    2008-01-01

    The correlation between aquaporin 1 (AQP1) and hypoxia-inducible factor 1 (HIF 1) in breast cancer tissues was preliminarily studied. In 155 cases of breast cancer, the expression levels of AQP1 were detected by immunohistochemisty in HIF1-positive group or HIF1-negative group, and the correlation between AQP1 and HIF1 was analyzed. The overexpression of AQP1 and HIF1 were observed in 155 cases of breast cancer tissues. The expression level of AQP1 in HIF1-positive group was significantly higher than that in HIF1-negative group. The positive expression rate of AQP1 was 296.55±24.67 and 168.37±37.53 in HIF1-positive group and HIF1-negative group respectively with the difference being very significant between them (P<0.001). It was concluded that AQP1 was overexpressed in the HIF1-positive group and there were some correlations between AQP1 and HIF1, suggesting they interact each other and regulate the oncogenesis of breast cancer.

  2. Role of Hypoxia Inducible Factor-1α (HIF-1α in Innate Defense against Uropathogenic Escherichia coli Infection.

    Directory of Open Access Journals (Sweden)

    Ann E Lin

    2015-04-01

    Full Text Available Uropathogenic E. coli (UPEC is the primary cause of urinary tract infections (UTI affecting approximately 150 million people worldwide. Here, we revealed the importance of transcriptional regulator hypoxia-inducible factor-1 α subunit (HIF-1α in innate defense against UPEC-mediated UTI. The effects of AKB-4924, a HIF-1α stabilizing agent, were studied using human uroepithelial cells (5637 and a murine UTI model. UPEC adherence and invasion were significantly reduced in 5637 cells when HIF-1α protein was allowed to accumulate. Uroepithelial cells treated with AKB-4924 also experienced reduced cell death and exfoliation upon UPEC challenge. In vivo, fewer UPEC were recovered from the urine, bladders and kidneys of mice treated transurethrally with AKB-4924, whereas increased bacteria were recovered from bladders of mice with a HIF-1α deletion. Bladders and kidneys of AKB-4924 treated mice developed less inflammation as evidenced by decreased pro-inflammatory cytokine release and neutrophil activity. AKB-4924 impairs infection in uroepithelial cells and bladders, and could be correlated with enhanced production of nitric oxide and antimicrobial peptides cathelicidin and β-defensin-2. We conclude that HIF-1α transcriptional regulation plays a key role in defense of the urinary tract against UPEC infection, and that pharmacological HIF-1α boosting could be explored further as an adjunctive therapy strategy for serious or recurrent UTI.

  3. Hypoxia-inducible factor-1α activation improves renal oxygenation and mitochondrial function in early chronic kidney disease.

    Science.gov (United States)

    Thomas, Joanna L; Pham, Hai; Li, Ying; Hall, Elanore; Perkins, Guy A; Ali, Sameh S; Patel, Hemal H; Singh, Prabhleen

    2017-08-01

    The pathophysiology of chronic kidney disease (CKD) is driven by alterations in surviving nephrons to sustain renal function with ongoing nephron loss. Oxygen supply-demand mismatch, due to hemodynamic adaptations, with resultant hypoxia, plays an important role in the pathophysiology in early CKD. We sought to investigate the underlying mechanisms of this mismatch. We utilized the subtotal nephrectomy (STN) model of CKD to investigate the alterations in renal oxygenation linked to sodium (Na) transport and mitochondrial function in the surviving nephrons. Oxygen delivery was significantly reduced in STN kidneys because of lower renal blood flow. Fractional oxygen extraction was significantly higher in STN. Tubular Na reabsorption was significantly lower per mole of oxygen consumed in STN. We hypothesized that decreased mitochondrial bioenergetic capacity may account for this and uncovered significant mitochondrial dysfunction in the early STN kidney: higher oxidative metabolism without an attendant increase in ATP levels, elevated superoxide levels, and alterations in mitochondrial morphology. We further investigated the effect of activation of hypoxia-inducible factor-1α (HIF-1α), a master regulator of cellular hypoxia response. We observed significant improvement in renal blood flow, glomerular filtration rate, and tubular Na reabsorption per mole of oxygen consumed with HIF-1α activation. Importantly, HIF-1α activation significantly lowered mitochondrial oxygen consumption and superoxide production and increased mitochondrial volume density. In conclusion, we report significant impairment of renal oxygenation and mitochondrial function at the early stages of CKD and demonstrate the beneficial role of HIF-1α activation on renal function and metabolism.

  4. Reversing hypoxic cell chemoresistance in vitro using genetic and small molecule approaches targeting hypoxia inducible factor-1.

    Science.gov (United States)

    Brown, Louisa M; Cowen, Rachel L; Debray, Camille; Eustace, Amanda; Erler, Janine T; Sheppard, Freda C D; Parker, Catriona A; Stratford, Ian J; Williams, Kaye J

    2006-02-01

    The resistance of hypoxic cells to conventional chemotherapy is well documented. Using both adenovirus-mediated gene delivery and small molecules targeting hypoxia-inducible factor-1 (HIF-1), we evaluated the impact of HIF-1 inhibition on the sensitivity of hypoxic tumor cells to etoposide. The genetic therapy exploited a truncated HIF-1alpha protein that acts as a dominant-negative HIF-1alpha (HIF-1alpha-no-TAD). Its functionality was validated in six human tumor cell lines using HIF-1 reporter assays. An EGFP-fused protein demonstrated that the dominant-negative HIF-1alpha was nucleus-localized and constitutively expressed irrespective of oxygen tension. The small molecules studied were quinocarmycin monocitrate (KW2152), its analog 7-cyanoquinocarcinol (DX-52-1), and topotecan. DX-52-1 and topotecan have been previously established as HIF-1 inhibitors. HT1080 and HCT116 cells were treated with either AdHIF-1alpha-no-TAD or nontoxic concentrations (0.1 microM; TAD (multiplicity of infection 50) ablated the anoxic resistance in both cell lines (IC(50) values: HT1080, 0.7 +/- 0.04 microM; HCT116, 3 +/- 1 microM). HIF-1alpha-no-TAD expression inhibited HIF-1-mediated down-regulation of the proapoptotic protein Bid under anoxia. These data support the potential development of HIF-1 targeted approaches in combination with chemotherapy, where hypoxic cell resistance contributes to treatment failure.

  5. Quantifying the Binding Interaction between the Hypoxia-Inducible Transcription Factor and the von Hippel-Lindau Suppressor.

    Science.gov (United States)

    Domene, Carmen; Jorgensen, Christian; Vanommeslaeghe, Kenno; Schofield, Christopher J; MacKerell, Alexander

    2015-08-11

    The hypoxia-inducible transcription factors (HIF) play a central role in the human oxygen sensing signaling pathway. The binding of the von Hippel-Lindau tumor suppressor protein (pVHL)-ElonginC-ElonginB complex (VCB) to HIF-1α is highly selective for the trans-4-hydroxylation form of when Pro564 in the C-terminal oxygen-dependent degradation domain (ODDD) of HIF-1α. The binding of HIFα for VCB is increased by ∼1000-fold upon addition of a single hydroxyl group to either of two conserved proline-residues. Here, we address how this addition governs selective recognition and characterizes the strength of the interaction of this "switch-like" signaling event. A new set of molecular mechanics parameters for 4-hydroxyproline has been developed following the CHARMM force field philosophy. Using the free energy perturbation (FEP) formalism, the difference in the binding free energies between HIF-1α in the nonhydroxylated and hydroxylated forms with the VCB complex was estimated using over 3 μs of MD trajectories. These results can favorably be compared to an experimental value of ∼4 kcal mol(-1). It is observed that the optimized hydrogen bonding network to the buried hydroxyprolyl group confers precise discrimination between hydroxylated and unmodified prolyl residues. These observations provide insight that will aid in developing therapeutic agents that block HIF-α recognition by pVHL.

  6. Intracellular ascorbate enhances hypoxia-inducible factor (HIF)-hydroxylase activity and preferentially suppresses the HIF-1 transcriptional response.

    Science.gov (United States)

    Kuiper, Caroline; Dachs, Gabi U; Currie, Margaret J; Vissers, Margreet C M

    2014-04-01

    Hypoxia-inducible factor (HIF)-1 drives the transcription of hundreds of genes to support cell survival under conditions of microenvironmental and metabolic stress. HIF-1 is downregulated by iron-containing 2-oxoglutarate-dependent enzymes that require ascorbate as a cofactor. The HIF hydroxylases control both protein stability and the formation of an active transcription complex and, consequently, ascorbate could affect HIF-1α stabilization and/or gene expression, but the relative effect of ascorbate on these separate processes has not been well characterized. In this study we examined the effects of known intracellular ascorbate concentrations on both processes in response to various means of hydroxylase inhibition, including CoCl2, NiCl2, desferrioxamine, dimethyloxalylglycine, and hypoxia. Ascorbate inhibited HIF-1 activity most dramatically with all mechanisms of iron competition. In addition, HIF-1-dependent gene expression was effectively prevented by ascorbate and was inhibited even under conditions that allowed HIF-1α protein stabilization. This suggests that (1) ascorbate acts primarily to stabilize and reduce the iron atom in the hydroxylase active site and (2) the asparagine hydroxylase controlling HIF-1 transcriptional activity is particularly susceptible to fluctuations in intracellular ascorbate. These findings suggest that ascorbate plays a significant role in supporting HIF-hydroxylase function and that it could thereby modulate the cell survival response.

  7. Non-invasive Bioluminescence Imaging of Myoblast-Mediated Hypoxia-Inducible Factor-1 Alpha Gene Transfer

    Science.gov (United States)

    Gheysens, Olivier; Chen, Ian Y.; Rodriguez-Porcel, Martin; Chan, Carmel; Rasooly, Julia; Vaerenberg, Caroline; Paulmurugan, Ramasamy; Willmann, Juergen K.; Deroose, Christophe; Wu, Joseph; Gambhir, Sanjiv S.

    2011-01-01

    Purpose We tested a novel imaging strategy, in which both the survival of transplanted myoblasts and their therapeutic transgene expression, a recombinant hypoxia-inducible factor-1α (HIF-1α-VP2), can be monitored using firefly luciferase (fluc) and Renilla luciferase (hrl) bioluminescence reporter genes, respectively. Procedures The plasmid pUbi-hrl-pUbi-HIF-1α-VP2, which expresses both hrl and HIF-1α-VP2 using two ubiquitin promoters, was characterized in vitro. C2c12 myoblasts stably expressing fluc and transiently transfected with pUbi-hrl-pUbi-HIF-1α-VP2 were injected into the mouse hindlimb. Both hrl and fluc expression were monitored using bioluminescence imaging (BLI). Results Strong correlations existed between the expression of hRL and each of HIF-1α-VP2, VEGF, and PlGF (r2>0.83, r2>0.82, and r2>0.97, respectively). In vivo, both transplanted cells and HIF-1α-VP2 transgene expression were successfully imaged using BLI. Conclusions An objective evaluation of myoblast-mediated gene transfer in living mice can be performed by monitoring both the survival and the transgene expression of transplanted myoblasts using the techniques developed herein. PMID:21267661

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

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    Shun Zhang

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

  9. Prognostic value of Annexin A3 in human colorectal cancer and its correlation with hypoxia-inducible factor-1α

    Science.gov (United States)

    Xie, Yong-Qiu; Fu, DI; He, Zheng-Hua; Tan, Qing-Dong

    2013-12-01

    Annexins are a family of intracellular proteins that bind membrane phospholipids in a Ca(2+) concentration-dependent manner and are involved in cellular processes, including apoptosis, proliferation and differentiation. Hypoxia-inducible factor-1α (HIF-1α) has been hypothesized to be critical in the angiogenesis of tumors. We hypothesized that Annexin A3, a member of the Annexin family, and HIF-1α may be associated with each other in colorectal cancer. The expression of Annexin A3 and HIF-1α in 60 colorectal cancer tissues was assessed by immunohistochemistry to statistically analyze the association between the clinicopathological features and survival of these cases. In the present study, 65 and 47% of colorectal cancer specimens were found to show Annexin A3 and HIF-1α immunoreactivity, respectively. Annexin A3 expression was found to significantly correlate with tumor size and Dukes' stage (all PA3 and HIF-1α protein expression exhibited a similar pattern in these samples, and their expression was found to correlate with poor survival in colorectal cancer patients. The results of the current study indicated for the first time that the increased expression of Annexin A3 in colorectal cancer correlates significantly with tumor growth and poor prognosis. Furthermore, Annexin A3 has been found to correlate with HIF-1α expression. These observations highlight an improved understanding of the carcinogenesis of colorectal cancer.

  10. Assessment of hypoxia inducible factor levels in cancer cell lines upon hypoxic induction using a novel reporter construct.

    Directory of Open Access Journals (Sweden)

    Wenyu Zhou

    Full Text Available Hypoxia Inducible Factor (HIF signaling pathway is important for tumor cells with limited oxygen supplies, as it is shown to be involved in the process of proliferation and angiogenesis. Given its pivotal role in cancer biology, robust assays for tracking changes in HIF expression are necessary for understanding its regulation in cancer as well as developing therapies that target HIF signaling. Here we report a novel HIF reporter construct containing tandem repeats of minimum HIF binding sites upstream of eYFP coding sequence. We show that the reporter construct has an excellent signal to background ratio and the reporter activity is HIF dependent and directly correlates with HIF protein levels. By utilizing this new construct, we assayed HIF activity levels in different cancer cell lines cultured in various degrees of hypoxia. This analysis reveals a surprising cancer cell line specific variation of HIF activity in the same level of hypoxia. We further show that in two cervical cancer cell lines, ME180 and HeLa, the different HIF activity levels observed correlate with the levels of hsp90, a cofactor that protects HIF against VHL-independent degradation. This novel HIF reporter construct serves as a tool to rapidly define HIF activity levels and therefore the therapeutic capacity of potential HIF repressors in individual cancers.

  11. LXY6090 - a novel manassantin A derivative - limits breast cancer growth through hypoxia-inducible factor-1 inhibition.

    Science.gov (United States)

    Lai, Fangfang; Liu, Qian; Liu, Xiaoyu; Ji, Ming; Xie, Ping; Chen, Xiaoguang

    2016-01-01

    Hypoxia-inducible factor-1 (HIF-1) represents a novel antitumor target owing to its involvement in vital processes considered hallmarks of cancer phenotypes. Manassantin A (MA) derived from Saururus cernuus has been reported as a selective HIF-1 inhibitor. Herein, the structure of MA was optimized to achieve new derivatives with simple chemical properties while retaining its activity. LXY6090 was designed to replace the central tetrahydrofuran moiety of MA with a cyclopentane ring and was identified as a potent HIF-1 inhibitor with an IC50 value of 4.11 nM. It not only inhibited the activity of HIF-1 in breast cancer cells but also downregulated the protein level of HIF-1α, which depended on von Hippel-Lindau for proteasome degradation. The related biological evaluation showed that the activity of HIF-1 target genes, VEGF and IGF-2, was decreased by LXY6090 in breast cancer cell lines. LXY6090 presented potent antitumor activity in vitro. Furthermore, LXY6090 showed in vivo anticancer efficacy by decreasing the HIF-1α expression in nude mice bearing MX-1 tumor xenografts. In conclusion, our data provide a basis for the future development of the novel compound LXY6090 as a potential therapeutic agent for breast cancer.

  12. LXY6090 – a novel manassantin A derivative – limits breast cancer growth through hypoxia-inducible factor-1 inhibition

    Science.gov (United States)

    Lai, Fangfang; Liu, Qian; Liu, Xiaoyu; Ji, Ming; Xie, Ping; Chen, Xiaoguang

    2016-01-01

    Hypoxia-inducible factor-1 (HIF-1) represents a novel antitumor target owing to its involvement in vital processes considered hallmarks of cancer phenotypes. Manassantin A (MA) derived from Saururus cernuus has been reported as a selective HIF-1 inhibitor. Herein, the structure of MA was optimized to achieve new derivatives with simple chemical properties while retaining its activity. LXY6090 was designed to replace the central tetrahydrofuran moiety of MA with a cyclopentane ring and was identified as a potent HIF-1 inhibitor with an IC50 value of 4.11 nM. It not only inhibited the activity of HIF-1 in breast cancer cells but also downregulated the protein level of HIF-1α, which depended on von Hippel–Lindau for proteasome degradation. The related biological evaluation showed that the activity of HIF-1 target genes, VEGF and IGF-2, was decreased by LXY6090 in breast cancer cell lines. LXY6090 presented potent antitumor activity in vitro. Furthermore, LXY6090 showed in vivo anticancer efficacy by decreasing the HIF-1α expression in nude mice bearing MX-1 tumor xenografts. In conclusion, our data provide a basis for the future development of the novel compound LXY6090 as a potential therapeutic agent for breast cancer. PMID:27445487

  13. Role of Hypoxia Inducible Factor-1α (HIF-1α) in Innate Defense against Uropathogenic Escherichia coli Infection.

    Science.gov (United States)

    Lin, Ann E; Beasley, Federico C; Olson, Joshua; Keller, Nadia; Shalwitz, Robert A; Hannan, Thomas J; Hultgren, Scott J; Nizet, Victor

    2015-04-01

    Uropathogenic E. coli (UPEC) is the primary cause of urinary tract infections (UTI) affecting approximately 150 million people worldwide. Here, we revealed the importance of transcriptional regulator hypoxia-inducible factor-1 α subunit (HIF-1α) in innate defense against UPEC-mediated UTI. The effects of AKB-4924, a HIF-1α stabilizing agent, were studied using human uroepithelial cells (5637) and a murine UTI model. UPEC adherence and invasion were significantly reduced in 5637 cells when HIF-1α protein was allowed to accumulate. Uroepithelial cells treated with AKB-4924 also experienced reduced cell death and exfoliation upon UPEC challenge. In vivo, fewer UPEC were recovered from the urine, bladders and kidneys of mice treated transurethrally with AKB-4924, whereas increased bacteria were recovered from bladders of mice with a HIF-1α deletion. Bladders and kidneys of AKB-4924 treated mice developed less inflammation as evidenced by decreased pro-inflammatory cytokine release and neutrophil activity. AKB-4924 impairs infection in uroepithelial cells and bladders, and could be correlated with enhanced production of nitric oxide and antimicrobial peptides cathelicidin and β-defensin-2. We conclude that HIF-1α transcriptional regulation plays a key role in defense of the urinary tract against UPEC infection, and that pharmacological HIF-1α boosting could be explored further as an adjunctive therapy strategy for serious or recurrent UTI.

  14. Metabolic profiling reveals potential metabolic markers associated with Hypoxia Inducible Factor-mediated signalling in hypoxic cancer cells.

    Science.gov (United States)

    Armitage, Emily G; Kotze, Helen L; Allwood, J William; Dunn, Warwick B; Goodacre, Royston; Williams, Kaye J

    2015-10-28

    Hypoxia inducible factors (HIFs) plays an important role in oxygen compromised environments and therefore in tumour survival. In this research, metabolomics has been applied to study HIFs metabolic function in two cell models: mouse hepatocellular carcinoma and human colon carcinoma, whereby the metabolism has been profiled for a range of oxygen potentials. Wild type cells have been compared to cells deficient in HIF signalling to reveal its effect on cellular metabolism under normal oxygen conditions as well as low oxygen, hypoxic and anoxic environments. Characteristic responses to hypoxia that were conserved across both cell models involved the anti-correlation between 2-hydroxyglutarate, 2-oxoglutarate, fructose, hexadecanoic acid, hypotaurine, pyruvate and octadecenoic acid with 4-hydroxyproline, aspartate, cysteine, glutamine, lysine, malate and pyroglutamate. Further to this, network-based correlation analysis revealed HIF specific pathway responses to each oxygen condition that were also conserved between cell models. From this, 4-hydroxyproline was revealed as a regulating hub in low oxygen survival of WT cells while fructose appeared to be in HIF deficient cells. Pathways surrounding these hubs were built from the direct connections of correlated metabolites that look beyond traditional pathways in order to understand the mechanism of HIF response to low oxygen environments.

  15. Down-regulation of hypoxia-inducible factor-1 suppresses malignant biological behavior of triple-negative breast cancer cells.

    Science.gov (United States)

    Wang, Fang; Chang, Miaomiao; Shi, Yonghong; Jiang, Lili; Zhao, Jing; Hai, Ling; Sharen, Gaowa; Du, Hua

    2014-01-01

    This study is to investigate the effect and mechanism of reduced hypoxia-inducible factor (HIF)-1a expression on malignant behavior of MDA-MB-231 cells. HIF-1α expression was interfered by siRNA. Western blot was used to detect protein expression of HIF-1α, active fragments of caspase 3 and vimentin. Cell count, flow cytometry and Hoechst staining were used to evaluate cell growth and apoptosis. Matrigel invasion and wound scratch assay were performed to measure the ability of cell invasion and migration. After MDA-MB-231 cells were transfected with HIF-1α-targeted siRNA, HIF-1α protein expression was successfully interrupted and cell growth was retarded. Compared with random siRNA group, reduced HIF-1α protein expression in HIF-1α-targeted siRNA group facilitated cell apoptosis but had no effect on cell cycle. In addition, cells treated with HIF-1α-targeted siRNA expressed active fragments of caspase 3 (17 and 12 kD) after serum starvation for 0 to 60 h. Caspase 3 activity assay further confirmed the above finding. Reduced HIF-1α expression impaired the migration and invasiveness with a reduction in the expression of vimentin and CK18 protein. Inhibition of HIF-1α protein synthesis or enhancement of its degradation reversed its malignant phenotypes and could probably be a potential means for the treatment of triple-negative breast cancer.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-01-29

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

  17. Hypoxia-inducible factors and RAB22A mediate formation of microvesicles that stimulate breast cancer invasion and metastasis.

    Science.gov (United States)

    Wang, Ting; Gilkes, Daniele M; Takano, Naoharu; Xiang, Lisha; Luo, Weibo; Bishop, Corey J; Chaturvedi, Pallavi; Green, Jordan J; Semenza, Gregg L

    2014-08-05

    Extracellular vesicles such as exosomes and microvesicles (MVs) are shed by cancer cells, are detected in the plasma of cancer patients, and promote cancer progression, but the molecular mechanisms regulating their production are not well understood. Intratumoral hypoxia is common in advanced breast cancers and is associated with an increased risk of metastasis and patient mortality that is mediated in part by the activation of hypoxia-inducible factors (HIFs). In this paper, we report that exposure of human breast cancer cells to hypoxia augments MV shedding that is mediated by the HIF-dependent expression of the small GTPase RAB22A, which colocalizes with budding MVs at the cell surface. Incubation of naïve breast cancer cells with MVs shed by hypoxic breast cancer cells promotes focal adhesion formation, invasion, and metastasis. In breast cancer patients, RAB22A mRNA overexpression in the primary tumor is associated with decreased overall and metastasis-free survival and, in an orthotopic mouse model, RAB22A knockdown impairs breast cancer metastasis.

  18. Early expressions of hypoxia-inducible factor 1alpha and vascular endothelial growth factor increase the neuronal plasticity of activated endogenous neural stem cells after focal cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    Seung Song; Jong-Tae Park; Joo Young Na; Man-Seok Park; Jeong-Kil Lee; Min-Cheol Lee; Hyung-Seok Kim

    2014-01-01

    Endogenous neural stem cells become “activated” after neuronal injury, but the activation sequence and fate of endogenous neural stem cells in focal cerebral ischemia model are little known. We evaluated the relationships between neural stem cells and hypoxia-inducible fac-tor-1α and vascular endothelial growth factor expression in a photothromobotic rat stroke model using immunohistochemistry and western blot analysis. We also evaluated the chrono-logical changes of neural stem cells by 5-bromo-2′-deoxyuridine (BrdU) incorporation. Hypoxia-inducible factor-1α expression was initially increased from 1 hour after ischemic injury, followed by vascular endothelial growth factor expression. Hypoxia-inducible factor-1αimmunoreactivity was detected in the ipsilateral cortical neurons of the infarct core and peri-in-farct area. Vascular endothelial growth factor immunoreactivity was detected in bilateral cortex, but ipsilateral cortex staining intensity and numbers were greater than the contralateral cortex. Vascular endothelial growth factor immunoreactive cells were easily found along the peri-infarct area 12 hours after focal cerebral ischemia. The expression of nestin increased throughout the microvasculature in the ischemic core and the peri-infarct area in all experimental rats after 24 hours of ischemic injury. Nestin immunoreactivity increased in the subventricular zone during 12 hours to 3 days, and prominently increased in the ipsilateral cortex between 3-7 days. Nes-tin-labeled cells showed dual differentiation with microvessels near the infarct core and reactive astrocytes in the peri-infarct area. BrdU-labeled cells were increased gradually from day 1 in the ipsilateral subventricular zone and cortex, and numerous BrdU-labeled cells were observed in the peri-infarct area and non-lesioned cortex at 3 days. BrdU-labeled cells rather than neu-rons, were mainly co-labeled with nestin and GFAP. Early expressions of hypoxia-inducible factor-1α and

  19. AMP-Activated Protein Kinase α2 in Neutrophils Regulates Vascular Repair via Hypoxia-Inducible Factor-1α and a Network of Proteins Affecting Metabolism and Apoptosis

    Science.gov (United States)

    Abdel Malik, Randa; Zippel, Nina; Frömel, Timo; Heidler, Juliana; Zukunft, Sven; Walzog, Barbara; Ansari, Nariman; Pampaloni, Francesco; Wingert, Susanne; Rieger, Michael A.; Wittig, Ilka; Fisslthaler, Beate

    2017-01-01

    Rationale: The AMP-activated protein kinase (AMPK) is stimulated by hypoxia, and although the AMPKα1 catalytic subunit has been implicated in angiogenesis, little is known about the role played by the AMPKα2 subunit in vascular repair. Objective: To determine the role of the AMPKα2 subunit in vascular repair. Methods and Results: Recovery of blood flow after femoral artery ligation was impaired (>80%) in AMPKα2−/− versus wild-type mice, a phenotype reproduced in mice lacking AMPKα2 in myeloid cells (AMPKα2ΔMC). Three days after ligation, neutrophil infiltration into ischemic limbs of AMPKα2ΔMC mice was lower than that in wild-type mice despite being higher after 24 hours. Neutrophil survival in ischemic tissue is required to attract monocytes that contribute to the angiogenic response. Indeed, apoptosis was increased in hypoxic neutrophils from AMPKα2ΔMC mice, fewer monocytes were recruited, and gene array analysis revealed attenuated expression of proangiogenic proteins in ischemic AMPKα2ΔMC hindlimbs. Many angiogenic growth factors are regulated by hypoxia-inducible factor, and hypoxia-inducible factor-1α induction was attenuated in AMPKα2-deficient cells and accompanied by its enhanced hydroxylation. Also, fewer proteins were regulated by hypoxia in neutrophils from AMPKα2ΔMC mice. Mechanistically, isocitrate dehydrogenase expression and the production of α-ketoglutarate, which negatively regulate hypoxia-inducible factor-1α stability, were attenuated in neutrophils from wild-type mice but remained elevated in cells from AMPKα2ΔMC mice. Conclusions: AMPKα2 regulates α-ketoglutarate generation, hypoxia-inducible factor-1α stability, and neutrophil survival, which in turn determine further myeloid cell recruitment and repair potential. The activation of AMPKα2 in neutrophils is a decisive event in the initiation of vascular repair after ischemia. PMID:27777247

  20. Adenovirus-mediated hypoxia-inducible factor-1 alpha gene transfer induces angiogenesis and neurogenesis following cerebral ischemia in rats

    Institute of Scientific and Technical Information of China (English)

    Wanfu Wu; Xiu Chen; Zhen Yu; Changlin Hu; Wenqin Cai

    2008-01-01

    BACKGROUND: Hypoxia-inducible factor-1 (HIF-1) accumulates under conditions of hypoxia. HIF-1α target genes have pleiotropic effects on neurogenesis, neuroprotection and angiogenesis in the brain.OBJECTIVE: To investigate whether a recombinant adenovirus carrying HIF-1α can increase the expression of HIF-1α in vivo and thus promote angiogenesis and neurogenesis in a rat model of focal cerebral ischemia.DESIGN, TIME AND SETTING: The randomized, controlled experiment was performed at the Department of Neurobiology, Third Military Medical University of Chinese PLA from September 2006 to October 2007.MATERIALS: 68 healthy adult male Sprague-Dawley (SD) rats, weighing 230-250 g, were used. HIF-1α antibody was purchased from Wuhan Boster Company. Vascular endothelial growth factor (VEGF) antibody was purchased from Santa Cruz Biotech Company.METHODS: All 68 rats were induced with a transient middle cerebral artery occlusion (MCAO), according to the method of intra-luminal vascular occlusion. 54 rats, in which MCAO was successfully induced, were randomly divided into adenovirus (Ad) group and recombinant adenovirus with HIF-1αgene (Ad-HIF-1α) group (27 rats for each group). Rats were injected with 10 μL Ad (Ad group) or Ad-HIF-1α (Ad-HIF-1α group) into the lateral ventricle, 1 day after MCAO induction. MAIN OUTCOME MEASURES: Reverse transcription polymerase chain reaction was used to measure the expression of HIF-1α and of VEGF. Immunohistochemistry was used to detect the localization of HIF-1α, VEGF and factor Ⅷ in ischemic penumbra. Rat newborn nerve cells were labeled with 5-bromodeoxyuridine (BrdU) after ischemia. BrdU/neurofilament 200 (NF200) and BrdU/glial fibrillary acidic protein (GFAP) double labeled immunofluorescent histochemistry was used to identify the differentiation of newborn cells. Neurological function was evaluated using the modified neurological severity score (NSS).RESULTS: Compared with Ad, Ad-HIF-1αenhanced the expression of HIF-1

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

    Science.gov (United States)

    2013-10-01

    obese and overweight patients with ER+ breast cancer to neoadjuvant aromatase inhibitor therapy. My role in this clinical trial is to analyze HIF-1 and...with drug resistance in different cancer cell types, including chronic myeloid leukemia cells (Zhao et al. Oncogene. 2010), gastric cancer cells (Liu...Hypoxia- Inducible Factor 1 (HIF-1) in Aromatase Inhibitor Resistant Breast Cancer PRINCIPAL INVESTIGATOR: Armina Kazi CONTRACTING

  2. Identification of a Survival-independent Metastasis-enhancing Role of Hypoxia-inducible Factor-1  with a Hypoxia-tolerant Tumor Cell Line

    OpenAIRE

    2010-01-01

    During tumor progression, malignant cells must repeatedly survive microenvironmental stress. Hypoxia-inducible factor-1 (HIF-1) signaling has emerged as one major pathway allowing cellular adaptation to stress. Recent findings led to the hypothesis that HIF-1α may enhance the metastatic potential of tumor cells by a survival-independent mechanism. So far it has not been shown that HIF-1α also directly regulates invasive processes during metastasis in addition to conferring a survival advantag...

  3. The G protein-coupled receptor 30 is up-regulated by hypoxia-inducible factor-1alpha (HIF-1alpha) in breast cancer cells and cardiomyocytes.

    Science.gov (United States)

    Recchia, Anna Grazia; De Francesco, Ernestina Marianna; Vivacqua, Adele; Sisci, Diego; Panno, Maria Luisa; Andò, Sebastiano; Maggiolini, Marcello

    2011-03-25

    GPR30, also known as GPER, has been suggested to mediate rapid effects induced by estrogens in diverse normal and cancer tissues. Hypoxia is a common feature of solid tumors involved in apoptosis, cell survival, and proliferation. The response to low oxygen environment is mainly mediated by the hypoxia-inducible factor named HIF-1α, which activates signaling pathways leading to adaptive mechanisms in tumor cells. Here, we demonstrate that the hypoxia induces HIF-1α expression, which in turn mediates the up-regulation of GPER and its downstream target CTGF in estrogen receptor-negative SkBr3 breast cancer cells and in HL-1 cardiomyocytes. Moreover, we show that HIF-1α-responsive elements located within the promoter region of GPER are involved in hypoxia-dependent transcription of GPER, which requires the ROS-induced activation of EGFR/ERK signaling in both SkBr3 and HL-1 and cells. Interestingly, the apoptotic response to hypoxia was prevented by estrogens through GPER in SkBr3 cells. Taken together, our data suggest that the hypoxia-induced expression of GPER may be included among the mechanisms involved in the anti-apoptotic effects elicited by estrogens, particularly in a low oxygen microenvironment.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-11-15

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

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

    Science.gov (United States)

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

    2015-11-01

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

  6. Hypoxia-inducible factor-mediated induction of WISP-2 contributes to attenuated progression of breast cancer

    Directory of Open Access Journals (Sweden)

    Fuady JH

    2014-03-01

    Full Text Available Jerry H Fuady,1,* Mattia R Bordoli,1,* Irene Abreu-Rodríguez,1,* Glen Kristiansen,2 David Hoogewijs,1,** Daniel P Stiehl,1,** Roland H Wenger1,**1Institute of Physiology and Zurich Center for Human Physiology, University of Zurich, Zurich, Switzerland; 2University Hospital Bonn, Institute of Pathology, Bonn, Germany*,**These authors contributed equally to this workAbstract: Hypoxia and the hypoxia-inducible factor (HIF signaling pathway trigger the expression of several genes involved in cancer progression and resistance to therapy. Transcriptionally active HIF-1 and HIF-2 regulate overlapping sets of target genes, and only few HIF-2 specific target genes are known so far. Here we investigated oxygen-regulated expression of Wnt-1 induced signaling protein 2 (WISP-2, which has been reported to attenuate the progression of breast cancer. WISP-2 was hypoxically induced in low-invasive luminal-like breast cancer cell lines at both the messenger RNA and protein levels, mainly in a HIF-2α-dependent manner. HIF-2-driven regulation of the WISP2 promoter in breast cancer cells is almost entirely mediated by two phylogenetically and only partially conserved functional hypoxia response elements located in a microsatellite region upstream of the transcriptional start site. High WISP-2 tumor levels were associated with increased HIF-2α, decreased tumor macrophage density, and a better prognosis. Silencing WISP-2 increased anchorage-independent colony formation and recovery from scratches in confluent cell layers of normally low-invasive MCF-7 cancer cells. Interestingly, these changes in cancer cell aggressiveness could be phenocopied by HIF-2α silencing, suggesting that direct HIF-2-mediated transcriptional induction of WISP-2 gene expression might at least partially explain the association of high HIF-2α tumor levels with prolonged overall survival of patients with breast cancer.Keywords: invasion, metastasis, motility, oxygen, tumor, transcriptional

  7. Regulation of hypoxia-inducible factor-α isoforms and redox state by carotid body neural activity in rats.

    Science.gov (United States)

    Peng, Ying-Jie; Yuan, Guoxiang; Khan, Shakil; Nanduri, Jayasri; Makarenko, Vladislav V; Reddy, Vaddi Damodara; Vasavda, Chirag; Kumar, Ganesh K; Semenza, Gregg L; Prabhakar, Nanduri R

    2014-09-01

    Previous studies reported that chronic intermittent hypoxia (CIH) results in an imbalanced expression of hypoxia-inducible factor-α (HIF-α) isoforms and oxidative stress in rodents, which may be due either to the direct effect of CIH or indirectly via hitherto uncharacterized mechanism(s). As neural activity is a potent regulator of gene transcription, we hypothesized that carotid body (CB) neural activity contributes to CIH-induced HIF-α isoform expression and oxidative stress in the chemoreflex pathway. Experiments were performed on adult rats exposed to CIH for 10 days. Rats exposed to CIH exhibited: increased HIF-1α and decreased HIF-2α expression; increased NADPH oxidase 2 and decreased superoxide dismutase 2 expression; and oxidative stress in the nucleus tractus solitarius and rostral ventrolateral medulla as well as in the adrenal medulla (AM), a major end organ of the sympathetic nervous system. Selective ablation of the CB abolished these effects. In the AM, sympathetic activation by the CB chemoreflex mediates CIH-induced HIF-α isoform imbalance via muscarinic acetylcholine receptor-mediated Ca(2+) influx, and the resultant activation of mammalian target of rapamycin pathway and calpain proteases. Rats exposed to CIH presented with hypertension, elevated sympathetic activity and increased circulating catecholamines. Selective ablation of either the CB (afferent pathway) or sympathetic innervation to the AM (efferent pathway) abolished these effects. These observations uncover CB neural activity-dependent regulation of HIF-α isoforms and the redox state by CIH in the central and peripheral nervous systems associated with the chemoreflex.

  8. High-altitude hypoxia induces disorders of the brain-endocrine-immune network through activation of corticotropin-releasing factor and its type-1 receptors

    Institute of Scientific and Technical Information of China (English)

    Xue-qun CHEN; Fan-ping KONG; Yang ZHAO; Ji-zeng DU

    2012-01-01

    High-altitude hypoxia can induce physiological dysfunction and mountain sickness,but the underlying mechanism is not fully understood.Corticotrophin-releasing factor (CRF) and CRF type-1 receptors (CRFR1) are members of the CRF family and the essential controllers of the physiological activity of the hypothalamo-pituitary-adrenal (HPA) axis and modulators of endocrine and behavioral activity in response to various stressors.We have previously found that high-altitude hypoxia induces disorders of the brain-endocrine-immune network through activation of CRF and CRFR1 in the brain and periphery that include activation of the HPA axis in a time-and dose-dependent manner,impaired or improved learning and memory,and anxiety-like behavioral change.Meanwhile,hypoxia induces dysfunctions of the hypothalamo-pituitary-endocrine and immune systems,including suppression of growth and development,as well as inhibition of reproductive,metabolic and immune functions.In contrast,the small mammals that live on the Qinghai-Tibet Plateau alpine meadow display low responsiveness to extreme high-altitudehypoxia challenge,suggesting well-acclimatized genes and a physiological strategy that developed during evolution through interact-ions between the genes and environment.All the findings provide evidence for understanding the neuroendocrine mechanisms of hypoxia-induced physiological dysfunction.This review extends these findings.

  9. Hypoxia-inducible factor-1α contributes to brain edema after stroke by regulating aquaporins and glycerol distribution in brain.

    Science.gov (United States)

    Higashida, Tetsuhiro; Peng, Changya; Li, Jie; Dornbos, David; Teng, Kailing; Li, Xiaohua; Kinni, Harish; Guthikonda, Murali; Ding, Yuchuan

    2011-02-01

    Brain edema following stroke is a critical clinical problem due to its association with increased morbidity and mortality. Despite its significance, present treatment for brain edema simply provides symptomatic relief due to the fact that molecular mechanisms underlying brain edema remain poorly understood. The present study investigated the role of hypoxia-inducible factor-1α (HIF-1α) and aquaporins (AQP-4 and -9) in regulating cerebral glycerol accumulation and inducing brain edema in a rodent model of stroke. Two-hours of middle cerebral artery occlusion (MCAO) followed by reperfusion was performed in male Sprague-Dawley rats (250-280 g). Anti-AQP-4 antibody, anti-AQP-9 antibody, or 2-Methoxyestradiol (2ME2, an inhibitor of HIF-1α) was given at the time of MCAO. The rats were sacrificed at 1 and 24 hours after reperfusion and their brains were examined. Extracellular and intracellular glycerol concentration of brain tissue was calculated with an enzymatic glycerol assay. The protein expressions of HIF-1α, AQP-4 and AQP-9 were determined by Western blotting. Brain edema was measured by brain water content. Compared to control, edema (p < 0.01), increased glycerol (p < 0.05), and enhanced expressions of HIF-1α, AQP-4, and AQP-9 (p < 0.05) were observed after stroke. With inhibition of AQP-4, AQP-9 or HIF-1α, edema and extracellular glycerol were significantly (p < 0.01) decreased while intracellular glycerol was increased (p < 0.01) 1 hour after stroke. Inhibition of HIF-1α with 2ME2 suppressed (p < 0.01) the expression of AQP-4 and AQP-9. These findings suggest that HIF-1α serves as an upstream regulator of cerebral glycerol concentrations and brain edema via a molecular pathway involving AQP-4 and AQP-9. Pharmacological blockade of this pathway in stroke patients may provide novel therapeutic strategies.

  10. The therapeutic effect of recombinant human trefoil factor 3 on hypoxia-induced necrotizing enterocolitis in immature rat.

    Science.gov (United States)

    Zhang, Bing-Hong; Yu, Hong-Gang; Sheng, Zhi-Xiang; Luo, He-Sheng; Yu, Jie-Ping

    2003-11-15

    Trefoil peptides are a new class of regulatory peptides involved in mucosal protection and repair in the gastrointestinal tract. Among them, trefoil factor 3 (TFF3) (intestinal trefoil factor) is known to be cytoprotective in the gut. The aim of this study was to determine the effect of recombinant human trefoil factor 3 (rhTFF3) on hypoxia-induced necrotizing enterocolitis (NEC) in immature rats. In the present study, thirty-two 1-day-old Wistar rat pups were randomly divided into four groups. Group 1 served as nonhypoxic controls. Group 2 rats were subjected to hypoxia reoxygenation (H/O) and then were returned to their mothers. Groups 3 and 4 rats were subjected to H/O, were returned to their mothers, and were treated with rhTFF3 intraperitoneally (0.5 mg) and subcutaneously (0.2 mg), respectively, for the next 3 days. All animals were killed on day 4, and intestine specimens were obtained to determine the histological changes, tissue level of interleukin-8 (IL-8), tumor necrosis factor-alpha (TNF-alpha), malondialdehyde (MDA), prostaglandin E2 (PGE2), tromboxane B2 (TXB2), and nitric oxide (NO). In addition, the effects of rhTFF3 on abundance of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) were also investigated. In neonatal NEC (group 2), necrosis of villi and crypts and, in some cases, transmural necrosis was observed under light microscopy. Tissue level of interleukin-8, tumor necrosis factor-alpha, malondialdehyde, prostaglandin E2, tromboxane B2, and nitric oxide were significantly higher than group 1. In addition, abundance of inducible nitric oxide synthase and cyclooxygenase 2 was markedly increased. In groups 3 and 4, only very slight intestinal injury was observed. The tissue level of interleukin-8, tumor necrosis factor-alpha, malondialdehyde, prostaglandin E2, tromboxane B2, and nitric oxide were significantly decreased in comparison to the group 2. Meanwhile, the abundance of inducible nitric oxide synthase and cyclooxygenase

  11. The Effect of Pregnant Rat Swimming on Hypoxia-Inducible Factor-1α Levels of Neonatal Lung

    Directory of Open Access Journals (Sweden)

    Hajizade A

    2012-03-01

    Full Text Available Background: Uterine environment and fetal period can profoundly affect health of the neonat. Hypoxia-inducible factor-1α (HIF-1α is a transcription factor that regulates cellular stress responses and its activity is essential in both embryogenesis and postnatal life. The aim of the present study was to investigate the effects of maternal swimming on rat Pups' HIF-1α levels as a key regulator of oxygen in lungs.Methods: Sixteen female Wistar rats weighing 180- 200 grams were acclimated to a new environment consisting of equal light-darkness cycle and ad lib access to chow and adapted to the stress caused by water for two weeks. The rats were divided into two swimming and control groups. Swimming training began on the first day of pregnancy in a pool and continued for 3 weeks (1 h/day, 5 days/wk. Pups' lungs were removed two days after birth and their HIF-1α concentration was determined with enzyme-linked immunosorbent assay (ELISA. Statistical analysis of the data was done using independent t-test. A p-value smaller than 0.05 was considered statistically significant. Results: Swimming lead to a significant (P<0.001 increase in the Pups' lung HIF-1α levels compared with the control group. Although 3-wk period of swimming training, showed no significant increase in weight and also lung weight of newborns. Thus it can be concluded that swimming endurance training in pregnancy, can be considered as appropriate alternative in order to embryos development. Conclusion: Our research suggests that HIF-1α level is an essential element for the development of the lungs of embryos. Moreover, further studies on the lung HIF-1α levels at post-natal period with different modes of exercise will provide more clear insight into the mechanisms of the findings resulting from this study.

  12. Molecular characterization of hypoxia and hypoxia-inducible factor 1 alpha (HIF-1α) from Taiwan voles (Microtus kikuchii).

    Science.gov (United States)

    Jiang, Yi-Fan; Chou, Chung-Hsi; Lin, En-Chung; Chiu, Chih-Hsien

    2011-02-01

    Hypoxia-inducible factor 1 (HIF-1) is a transcription factor that senses and adapts cells to hypoxic environmental conditions. HIF-1 is composed of an oxygen-regulated α subunit (HIF-1α) and a constitutively expressed β subunit (HIF-1β). Taiwan voles (Microtus kikuchii) are an endemic species in Taiwan, found only in mountainous areas greater than 2000m above sea level. In this study, the full-length HIF-1α cDNA was cloned and sequenced from liver tissues of Taiwan voles. We found that HIF-1α of Taiwan voles had high sequence similarity to HIF-1α of other species. Sequence alignment of HIF-1α functional domains indicated basic helix-loop-helix (bHLH), PER-ARNT-SIM (PAS) and C-terminal transactivation (TAD-C) domains were conserved among species, but sequence variations were found between the oxygen-dependent degradation domains (ODDD). To measure Taiwan vole HIF-1α responses to hypoxia, animals were challenged with cobalt chloride, and HIF-1α mRNA and protein expression in brain, lung, heart, liver, kidney, and muscle was assessed by quantitative RT-PCR and Western blot analysis. Upon induction of hypoxic stress with cobalt chloride, an increase in HIF-1α mRNA levels was detected in lung, heart, kidney, and muscle tissue. In contrast, protein expression levels showed greater variation between individual animals. These results suggest that the regulation of HIF-1α may be important to the Taiwan vole under cobalt chloride treatments. But more details regarding the evolutionary effect of environmental pressure on HIF-1α primary sequence, HIF-1α function and regulation in Taiwan voles remain to be identified.

  13. MUC1 mucin stabilizes and activates hypoxia-inducible factor 1 alpha to regulate metabolism in pancreatic cancer

    Science.gov (United States)

    Chaika, Nina V.; Gebregiworgis, Teklab; Lewallen, Michelle E.; Purohit, Vinee; Radhakrishnan, Prakash; Liu, Xiang; Zhang, Bo; Mehla, Kamiya; Brown, Roger B.; Caffrey, Thomas; Yu, Fang; Johnson, Keith R.; Powers, Robert; Hollingsworth, Michael A.; Singh, Pankaj K.

    2012-01-01

    Aberrant glucose metabolism is one of the hallmarks of cancer that facilitates cancer cell survival and proliferation. Here, we demonstrate that MUC1, a large, type I transmembrane protein that is overexpressed in several carcinomas including pancreatic adenocarcinoma, modulates cancer cell metabolism to facilitate growth properties of cancer cells. MUC1 occupies the promoter elements of multiple genes directly involved in glucose metabolism and regulates their expression. Furthermore, MUC1 expression enhances glycolytic activity in pancreatic cancer cells. We also demonstrate that MUC1 expression enhances in vivo glucose uptake and expression of genes involved in glucose uptake and metabolism in orthotopic implantation models of pancreatic cancer. The MUC1 cytoplasmic tail is known to activate multiple signaling pathways through its interactions with several transcription factors/coregulators at the promoter elements of various genes. Our results indicate that MUC1 acts as a modulator of the hypoxic response in pancreatic cancer cells by regulating the expression/stability and activity of hypoxia-inducible factor-1α (HIF-1α). MUC1 physically interacts with HIF-1α and p300 and stabilizes the former at the protein level. By using a ChIP assay, we demonstrate that MUC1 facilitates recruitment of HIF-1α and p300 on glycolytic gene promoters in a hypoxia-dependent manner. Also, by metabolomic studies, we demonstrate that MUC1 regulates multiple metabolite intermediates in the glucose and amino acid metabolic pathways. Thus, our studies indicate that MUC1 acts as a master regulator of the metabolic program and facilitates metabolic alterations in the hypoxic environments that help tumor cells survive and proliferate under such conditions. PMID:22869720

  14. Downregulation and pro-apoptotic effect of hypoxia-inducible factor 2 alpha in hepatocellular carcinoma

    Science.gov (United States)

    Niu, Leilei; Sun, Yun-fan; Yang, Xing-rong; Fan, Jia; Ren, Jian-wei; Chen, George G.; Lai, Paul B.S.

    2016-01-01

    The role of HIF-2α in hepatocellular carcinoma (HCC) is unclear. The aim of the present study was to investigate the expression pattern and role of HIF-2α in HCC patients. Immunohistochemical staining and western blotting analyses were applied to detect the protein level of HIF-2α in 206 paired HCC and peritumoral tissues. Kaplan-Meier survival and Cox proportional hazard regression analyses were performed to identify risk factors for overall survival and recurrence-free survival in these patients. The function of HIF-2α was studied in HCC cells and in vivo models. We found that the protein levels of HIF-2α in HCC tissues were lower than in peritumoral tissues, and were negatively correlated with tumor size (P < 0.05). Kaplan-Meier survival and univariate analysis revealed that HCC patients with high HIF-2α protein levels had longer overall survival (P < 0.05). Over-expression of HIF-2α induced apoptosis in HCC cells and increased the levels of pro-apoptotic proteins, Bak, ZBP-89 and PDCD4, whereas the inhibition of HIF-2α expression achieved opposite results. The findings were confirmed in a mouse HCC xenograft model. In conclusion, our study revealed that HIF-2α was decreased and played an anti-tumorigenic role in HCC. PMID:27119229

  15. Decay accelerating factor (CD55 protects neuronal cells from chemical hypoxia-induced injury

    Directory of Open Access Journals (Sweden)

    Tsokos George C

    2010-04-01

    Full Text Available Abstract Background Activated complement system is known to mediate neuroinflammation and neurodegeneration following exposure to hypoxic-ischemic insults. Therefore, inhibition of the complement activation cascade may represent a potential therapeutic strategy for the management of ischemic brain injury. Decay-accelerating factor (DAF, also known as CD55 inhibits complement activation by suppressing the function of C3/C5 convertases, thereby limiting local generation or deposition of C3a/C5a and membrane attack complex (MAC or C5b-9 production. The present study investigates the ability of DAF to protect primary cultured neuronal cells subjected to sodium cyanide (NaCN-induced hypoxia from degeneration and apoptosis. Methods Cultured primary cortical neurons from embryonic Sprague-Dawley rats were assigned one of four groups: control, DAF treatment alone, hypoxic, or hypoxic treated with DAF. Hypoxic cultures were exposed to NaCN for 1 hour, rinsed, followed by 24 hour exposure to 200 ng/ml of recombinant human DAF in normal medium. Human DAF was used in the present study and it has been shown to effectively regulate complement activation in rats. Neuronal cell function, morphology and viability were investigated by measuring plateau depolarization potential, counting the number dendritic spines, and observing TUNEL and MTT assays. Complement C3, C3a, C3a receptor (R production, C3a-C3aR interaction and MAC formation were assessed along with the generation of activated caspase-9, activated caspase-3, and activated Src. Results When compared to controls, hypoxic cells had fewer dendritic spines, reduced plateau depolarization accompanied by increased apoptotic activity and accumulation of MAC, as well as up-regulation of C3, C3a and C3aR, enhancement of C3a-C3aR engagement, and elevated caspase and Src activity. Treatment of hypoxic cells with 200 ng/ml of recombinant human DAF resulted in attenuation of neuronal apoptosis and exerted

  16. Dauricine inhibits insulin-like growth factor-Ⅰ-induced hypoxia inducible factor 1α protein accumulation and vascular endothelial growth factor expression in human breast cancer cells

    Institute of Scientific and Technical Information of China (English)

    Xu-dong TANG; Xin ZHOU; Ke-yuan ZHOU

    2009-01-01

    Aim: To investigate the effects of dauricine (Dau) on insulin-like growth factor-Ⅰ (IGF-Ⅰ)-induced hypoxia inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF) expression in human breast cancer cells (MCF-7).Methods: Serum-starved MCF-7 cells were pretreated for 1 h with different concentrations of Dau, followed by incubation with IGF-Ⅰ for 6 h. HIF-1α and VEGF protein expression levels were analyzed by Western blotting and ELISA, respectively.HIF-1α and VEGF mRNA levels were determined by real-time PCR. In vitro angiogenesis was observed via the human umbilical vein endothelial cell (HUVEC) tube formation assay. An in vitro invasion assay on HUVECs was performed.Results: Dau significantly inhibited IGF-Ⅰ-induced HIF-1α protein expression but had no effect on HIF-1α mRNA expression. However, Dau remarkably suppressed VEGF expression at both protein and mRNA levels in response to IGF-Ⅰ.Mechanistically, Dau suppressed IGF-Ⅰ-induced HIF-1α and VEGF protein expression mainly by blocking the activation of PI-3K/AKT/mTOR signaling pathway. In addition, Dan reduced IGF-Ⅰ-induced HIF-1α protein accumulation by inhibiting its synthesis as well as by promoting its degradation. Functionally, Dau inhibited angiogenesis in vitro. Moreover, Dau had a direct effect on IGF-Ⅰ-induced invasion of HUVECs.Conclusion: Dau inhibits human breast cancer angiogenesis by suppressing HIF-1α protein accumulation and VEGF expression, which may provide a novel potential mechanism for the anticancer activities of Dau in human breast cancer.

  17. The prognostic significance of hypoxia inducing factor 1-α in oropharyngeal cancer in relation to human papillomavirus status.

    Science.gov (United States)

    Hong, Angela; Zhang, Mei; Veillard, Anne-Sophie; Jahanbani, Jahanfar; Lee, C Soon; Jones, Deanna; Harnett, Gerald; Clark, Jonathan; Elliott, Michael; Milross, Chris; Rose, Barbara

    2013-04-01

    This study examines the prognostic significance of hypoxia inducing factor-1α (HIF-1α) expression in relation to human papillomavirus (HPV) status in oropharyngeal squamous cell carcinoma (SCC). Clinical details on 233 oropharyngeal SCCs were extracted from institutional databases. Recurrence in any form or death from any cause was recorded for a median of 51 months after diagnosis. HIF-1α expression was evaluated by semiquantitative immunohistochemistry and HPV status was determined by HPV E6-targeted multiplex real-time PCR and p16 immunohistochemistry. Determinants of recurrence and mortality hazards were modeled using Cox regression with censoring at dates of last follow-up. The HIF-1α positivity rate was 58.8%. HIF-1α positivity was associated with higher T category (T3/T4 vs. T1/T2, 64.2% vs. 48.4%, p=0.001) and lower grade (Grade 1-2 vs. 3, 62% vs. 46.9%, p=0.001). There was no significant association between HIF-1α expression and HPV status. After adjustment for clinico-pathological variables, HPV status but not HIF-1α was a strong predictor of outcome. The combination of HPV and HIF-1α was not a prognostic variable but the worst outcomes were seen in those with HPV negative and HIF-1α positive cancers. There was no statistically significant evidence of an interaction between HPV and HIF-1α. The degree of hypoxia as measured by HIF-1α expression does not differ between HPV positive and HPV negative cancers. The role of hypoxia in HPV negative oropharyngeal cancer warrants further investigation. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  18. Hypoxia inducible factor-2α regulates the development of retinal astrocytic network by maintaining adequate supply of astrocyte progenitors.

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    Li-Juan Duan

    Full Text Available Here we investigate the role of hypoxia inducible factor (HIF-2α in coordinating the development of retinal astrocytic and vascular networks. Three Cre mouse lines were used to disrupt floxed Hif-2α, including Rosa26(CreERT2, Tie2(Cre, and GFAP(Cre. Global Hif-2α disruption by Rosa26(CreERT2 led to reduced astrocytic and vascular development in neonatal retinas, whereas endothelial disruption by Tie2(Cre had no apparent effects. Hif-2α deletion in astrocyte progenitors by GFAP(Cre significantly interfered with the development of astrocytic networks, which failed to reach the retinal periphery and were incapable of supporting vascular development. Perplexingly, the abundance of strongly GFAP(+ mature astrocytes transiently increased at P0 before they began to lag behind the normal controls by P3. Pax2(+ and PDGFRα(+ astrocytic progenitors and immature astrocytes were dramatically diminished at all stages examined. Despite decreased number of astrocyte progenitors, their proliferation index or apoptosis was not altered. The above data can be reconciled by proposing that HIF-2α is required for maintaining the supply of astrocyte progenitors by slowing down their differentiation into non-proliferative mature astrocytes. HIF-2α deficiency in astrocyte progenitors may accelerate their differentiation into astrocytes, a change which greatly interferes with the replenishment of astrocyte progenitors due to insufficient time for proliferation. Rapidly declining progenitor supply may lead to premature cessation of astrocyte development. Given that HIF-2α protein undergoes oxygen dependent degradation, an interesting possibility is that retinal blood vessels may regulate astrocyte differentiation through their oxygen delivery function. While our findings support the consensus that retinal astrocytic template guides vascular development, they also raise the possibility that astrocytic and vascular networks may mutually regulate each other

  19. Class II histone deacetylases are associated with VHL-independent regulation of hypoxia-inducible factor 1 alpha.

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    Qian, David Z; Kachhap, Sushant K; Collis, Spencer J; Verheul, Henk M W; Carducci, Michael A; Atadja, Peter; Pili, Roberto

    2006-09-01

    Hypoxia-inducible factor 1 alpha (HIF-1 alpha) plays a critical role in transcriptional gene activation involved in tumor angiogenesis. A novel class of agents, the histone deacetylase (HDAC) inhibitors, has been shown to inhibit tumor angiogenesis and HIF-1 alpha protein expression. However, the molecular mechanism responsible for this inhibition remains to be elucidated. In the current study, we investigated the molecular link between HIF-1 alpha inhibition and HDAC inhibition. Treatment of the VHL-deficient human renal cell carcinoma cell line UMRC2 with the hydroxamic HDAC inhibitor LAQ824 resulted in a dose-dependent inhibition of HIF-1 alpha protein via a VHL-independent mechanism and reduction of HIF-1 alpha transcriptional activity. HIF-1 alpha inhibition by LAQ824 was associated with HIF-1 alpha acetylation and polyubiquitination. HIF-1 alpha immunoprecipitates contained HDAC activity. Then, we tested different classes of HDAC inhibitors with diverse inhibitory activity of class I versus class II HDACs and assessed their capability of targeting HIF-1 alpha. Hydroxamic acid derivatives with known activity against both class I and class II HDACs were effective in inhibiting HIF-1 alpha at low nanomolar concentrations. In contrast, valproic acid and trapoxin were able to inhibit HIF-1 alpha only at concentrations that are effective against class II HDACs. Coimmunoprecipitation studies showed that class II HDAC4 and HDAC6 were associated with HIF-1 alpha protein. Inhibition by small interfering RNA of HDAC4 and HDAC6 reduced HIF-1 alpha protein expression and transcriptional activity. Taken together, these results suggest that class II HDACs are associated with HIF-1 alpha stability and provide a rationale for targeting HIF-1 alpha with HDAC inhibitors against class II isozymes.

  20. Mutual antagonism between hypoxia-inducible factors 1α and 2α regulates oxygen sensing and cardio-respiratory homeostasis.

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    Yuan, Guoxiang; Peng, Ying-Jie; Reddy, Vaddi Damodara; Makarenko, Vladislav V; Nanduri, Jayasri; Khan, Shakil A; Garcia, Joseph A; Kumar, Ganesh K; Semenza, Gregg L; Prabhakar, Nanduri R

    2013-05-07

    Breathing and blood pressure are under constant homeostatic regulation to maintain optimal oxygen delivery to the tissues. Chemosensory reflexes initiated by the carotid body and catecholamine secretion from the adrenal medulla are the principal mechanisms for maintaining respiratory and cardiovascular homeostasis; however, the underlying molecular mechanisms are not known. Here, we report that balanced activity of hypoxia-inducible factor-1 (HIF-1) and HIF-2 is critical for oxygen sensing by the carotid body and adrenal medulla, and for their control of cardio-respiratory function. In Hif2α(+/-) mice, partial HIF-2α deficiency increased levels of HIF-1α and NADPH oxidase 2, leading to an oxidized intracellular redox state, exaggerated hypoxic sensitivity, and cardio-respiratory abnormalities, which were reversed by treatment with a HIF-1α inhibitor or a superoxide anion scavenger. Conversely, in Hif1α(+/-) mice, partial HIF-1α deficiency increased levels of HIF-2α and superoxide dismutase 2, leading to a reduced intracellular redox state, blunted oxygen sensing, and impaired carotid body and ventilatory responses to chronic hypoxia, which were corrected by treatment with a HIF-2α inhibitor. None of the abnormalities observed in Hif1α(+/-) mice or Hif2α(+/-) mice were observed in Hif1α(+/-);Hif2α(+/-) mice. These observations demonstrate that redox balance, which is determined by mutual antagonism between HIF-α isoforms, establishes the set point for hypoxic sensing by the carotid body and adrenal medulla, and is required for maintenance of cardio-respiratory homeostasis.

  1. The effects of hypoxia-inducible factor (HIF)-1α protein on bone regeneration during distraction osteogenesis: an animal study.

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    Jiang, X; Zhang, Y; Fan, X; Deng, X; Zhu, Y; Li, F

    2016-02-01

    The aim of this study was to observe the effect of hypoxia-inducible factor (HIF)-1α on bone regeneration during distraction osteogenesis (DO). Fifty-one New Zealand white rabbits underwent mandibular lengthening with a distraction rate of 2mm/day, and were divided randomly into three groups (17 in each). Group C rabbits received 20 μg rHIF-1α, group B received 10 μg rHIF-1α, and group A received 100 μl saline injection in the distraction gap every day for 10 days. Radionuclide bone imaging (RBI), computed tomography, dual energy X-ray absorptiometry, radiography, histology, and three-point bend testing were performed. RBI showed that the uptake ratio in group B (1.41 ± 0.25, P=0.013) and group C (1.64 ± 0.37, P<0.001) was higher than that in group A (1.01 ± 0.26). The bone mineralization density and bone mineralization content in group C were highest among the three groups. Radiology and histology findings indicated more callus regeneration in groups C and B. Mechanical testing demonstrated that the ultimate force in group C (289.71 ± 43.31N, n=6) was 1.49-fold (P<0.001) that of group A and 1.20-fold (P=0.012) that of group B. HIF-1α may represent a new agent to promote DO by accelerating osteogenesis and mineralization.

  2. Xanthine oxidase mediates hypoxia-inducible factor-2α degradation by intermittent hypoxia.

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    Jayasri Nanduri

    Full Text Available Sleep-disordered breathing with recurrent apnea produces chronic intermittent hypoxia (IH. We previously reported that IH leads to down-regulation of HIF-2α protein via a calpain-dependent signaling pathway resulting in oxidative stress. In the present study, we delineated the signaling pathways associated with calpain-dependent HIF-2α degradation in cell cultures and rats subjected to chronic IH. Reactive oxygen species (ROS scavengers prevented HIF-2α degradation by IH and ROS mimetic decreased HIF-2α protein levels in rat pheochromocytoma PC12 cell cultures, suggesting that ROS mediate IH-induced HIF-2α degradation. IH activated xanthine oxidase (XO by increased proteolytic conversion of xanthine dehydrogenase to XO. ROS generated by XO activated calpains, which contributed to HIF-2α degradation by IH. Calpain-induced HIF-2α degradation involves C-terminus but not the N-terminus of the HIF-2α protein. Pharmacological blockade as well as genetic knock down of XO prevented IH induced calpain activation and HIF-2α degradation in PC12 cells. Systemic administration of allopurinol to rats prevented IH-induced hypertension, oxidative stress and XO activation in adrenal medulla. These results demonstrate that ROS generated by XO activation mediates IH-induced HIF-2α degradation via activation of calpains.

  3. An association study between hypoxia inducible factor-1alpha (HIF-1α polymorphisms and osteonecrosis.

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    Georgia Chachami

    Full Text Available Bone hypoxia resulting from impaired blood flow is the final pathway for the development of osteonecrosis (ON. The aim of this study was to evaluate if HIF-1α, the major transcription factor triggered by hypoxia, is genetically implicated in susceptibility to ON. For this we analyzed frequencies of three known HIF-1α polymorphisms: one in exon 2 (C111A and two in exon 12 (C1772T and G1790A and their association with ON in a Greek population. Genotype analysis was performed using PCR-RFLP and rare alleles were further confirmed with sequencing. We found that genotype and allele frequency of C1772T and G1790A SNP of HIF-1α (SNPs found in our cohort were not significantly different in ON patients compared to control patients. Furthermore these SNPs could not be associated with the different subgroups of ON. At the protein level we observed that the corresponding mutations (P582S and A588T, respectively are not significant for protein function since the activity, expression and localization of the mutant proteins is practically indistinguishable from wt in HEK293 and Saos-2 cells. These results suggest that these missense mutations in the HIF-1α gene are not important for the risk of developing ON.

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

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    Li Zheng

    2010-10-01

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

  5. Hypoxia Inducible Factor-2 Alpha and Prolinhydroxylase 2 Polymorphisms in Patients with Acute Respiratory Distress Syndrome (ARDS

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    Annika Dötsch

    2017-06-01

    Full Text Available Hypoxia-inducible-factor-2α (HIF-2α and HIF-2 degrading prolyl-hydroxylases (PHD are key regulators of adaptive hypoxic responses i.e., in acute respiratory distress syndrome (ARDS. Specifically, functionally active genetic variants of HIF-2α (single nucleotide polymorphism (SNP [ch2:46441523(hg18] and PHD2 (C/T; SNP rs516651 and T/C; SNP rs480902 are associated with improved adaptation to hypoxia i.e., in high-altitude residents. However, little is known about these SNPs’ prevalence in Caucasians and impact on ARDS-outcome. Thus, we tested the hypotheses that in Caucasian ARDS patients SNPs in HIF-2α or PHD2 genes are (1 common, and (2 independent risk factors for 30-day mortality. After ethics-committee approval, 272 ARDS patients were prospectively included, genotyped for PHD2 (Taqman SNP Genotyping Assay and HIF-2α-polymorphism (restriction digest + agarose-gel visualization, and genotype dependent 30-day mortality was analyzed using Kaplan-Meier-plots and multivariate Cox-regression analyses. Frequencies were 99.62% for homozygous HIF-2α CC-carriers (CG: 0.38%; GG: 0%, 2.3% for homozygous PHD2 SNP rs516651 TT-carriers (CT: 18.9%; CC: 78.8%, and 3.7% for homozygous PHD2 SNP rs480902 TT-carriers (CT: 43.9%; CC: 52.4%. PHD2 rs516651 TT-genotype in ARDS was independently associated with a 3.34 times greater mortality risk (OR 3.34, CI 1.09–10.22; p = 0.034 within 30-days, whereas the other SNPs had no significant impact (p = ns. The homozygous HIF-2α GG-genotype was not present in our Caucasian ARDS cohort; however PHD2 SNPs exist in Caucasians, and PHD2 rs516651 TT-genotype was associated with an increased 30-day mortality suggesting a relevance for adaptive responses in ARDS.

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

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    Julie Y H Chan

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

  7. Hypoxia inducible factors regulate the transcription of the sprouty2 gene and expression of the sprouty2 protein

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    Neumann, Paul; Patel, Tarun B.

    2017-01-01

    Receptor Tyrosine Kinase (RTK) signaling plays a major role in tumorigenesis and normal development. Sprouty2 (Spry2) attenuates RTK signaling and inhibits processes such as angiogenesis, cell proliferation, migration and survival, which are all upregulated in tumors. Indeed in cancers of the liver, lung, prostate and breast, Spry2 protein levels are markedly decreased correlating with poor patient prognosis and shorter survival. Thus, it is important to understand how expression of Spry2 is regulated. While prior studies have focused on the post-translation regulation of Spry2, very few studies have focused on the transcriptional regulation of SPRY2 gene. Here, we demonstrate that in the human hepatoma cell line, Hep3B, the transcription of SPRY2 is inhibited by the transcription regulating hypoxia inducible factors (HIFs). HIFs are composed of an oxygen regulated alpha subunit (HIF1α or HIF2α) and a beta subunit (HIF1β). Intriguingly, silencing of HIF1α and HIF2α elevates SPRY2 mRNA and protein levels suggesting HIFs reduce the transcription of the SPRY2 promoter. In silico analysis identified ten hypoxia response elements (HREs) in the proximal promoter and first intron of SPRY2. Using chromatin immunoprecipitation (ChIP), we show that HIF1α/2α bind near the putative HREs in the proximal promoter and intron of SPRY2. Our studies demonstrated that not only is the SPRY2 promoter methylated, but silencing HIF1α/2α reduced the methylation. ChIP assays also showed DNA methyltransferase1 (DNMT1) binding to the proximal promoter and first intron of SPRY2 and silencing HIF1α/2α decreased this association. Additionally, silencing of DNMT1 mimicked the HIF1α/2α silencing-mediated increase in SPRY2 mRNA and protein. While simultaneous silencing of HIF1α/2α and DNMT1 increased SPRY2 mRNA a little more, the increase was not additive suggesting a common mechanism by which DNMT1 and HIF1α/2α regulate SPRY2 transcription. Together these data suggest that the

  8. Expression and function of hypoxia inducible factor-1 alpha in human melanoma under non-hypoxic conditions

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    Joshi Sandeep S

    2009-11-01

    Full Text Available Abstract Background Hypoxia inducible factor-1 alpha (HIF-1α protein is rapidly degraded under normoxic conditions. When oxygen tensions fall HIF-1α protein stabilizes and transactivates genes involved in adaptation to hypoxic conditions. We have examined the normoxic expression of HIF-1α RNA and protein in normal human melanocytes and a series of human melanoma cell lines isolated from radial growth phase (RGP, vertical growth phase (VGP and metastatic (MET melanomas. Results HIF-1α mRNA and protein was increased in RGP vs melanocytes, VGP vs RGP and MET vs VGP melanoma cell lines. We also detected expression of a HIF-1α mRNA splice variant that lacks part of the oxygen-dependent regulation domain in WM1366 and WM9 melanoma cells. Over-expression of HIF-1α and its splice variant in the RGP cell line SbCl2 resulted in a small increase in soft agar colony formation and a large increase in matrigel invasion relative to control transfected cells. Knockdown of HIF-1α expression by siRNA in the MET WM9 melanoma cell line resulted in a large decrease in both soft agar colony formation and matrigel invasion relative to cells treated with non-specific siRNA. There is a high level of ERK1/2 phosphorylation in WM9 cells, indicating an activated Ras-Raf-MEK-ERK1/2 MAPK pathway. Treatment of WM9 cells with 30 μM U0126 MEK inhibitor, decreased ERK1/2 phosphorylation and resulted in a decrease in HIF-1α expression. However, a 24 h treatment with 10 μM U0126 totally eliminated Erk1/2 phosphorylation, but did not change HIF-1alpha levels. Furthermore, siRNA knockdown of MEK siRNA did not change HIF-1alpha levels. Conclusion We speculate that metabolic products of U0126 decrease HIF-1alpha expression through "off target" effects. Overall our data suggest that increased HIF-1α expression under normoxic conditions contributes to some of the malignant phenotypes exhibited by human melanoma cells. The expanded role of HIF-1α in melanoma biology increases

  9. Interaction between obesity and the Hypoxia Inducible Factor 3 Alpha Subunit rs3826795 polymorphism in relation with plasma alanine aminotransferase.

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    Wang, Shuo; Song, Jieyun; Yang, Yide; Zhang, Yining; Chawla, Nitesh V; Ma, Jun; Wang, Haijun

    2017-07-28

    Hypoxia Inducible Factor 3 Alpha Subunit (HIF3A) DNA has been demonstrated to be associated with obesity in the methylation level, and it also has a Body Mass Index (BMI)-independent association with plasma alanine aminotransferase (ALT). However, the relation among obesity, plasma ALT, HIF3A polymorphism and methylation remains unclear. This study aims to identify the association between HIF3A polymorphism and plasma ALT, and further to determine whether the effect of HIF3A polymorphism on ALT could be modified by obesity or mediated by DNA methylation. The HIF3A rs3826795 polymorphism was genotyped in a case-control study including 2030 Chinese children aged 7-18 years (705 obese cases and 1325 non-obese controls). Furthermore, the HIF3A DNA methylation of the peripheral blood was measured in 110 severely obese children and 110 age- and gender- matched normal-weight controls. There was no overall association between the HIF3A rs3826795 polymorphism and ALT. A significant interaction between obesity and rs3826795 in relation with ALT was found (P inter = 0.042), with rs3826795 G-allele number elevating ALT significantly only in obese children (β' = 0.075, P = 0.037), but not in non-obese children (β' = -0.009, P = 0.741). Additionally, a mediation effect of HIF3A methylation was found in the association between the HIF3A rs3826795 polymorphism and ALT among obese children (β' = 0.242, P = 0.014). This is the first study to report the interaction between obesity and HIF3A gene in relation with ALT, and also to reveal a mediation effect among the HIF3A polymorphism, methylation and ALT. This study provides new evidence to the function of HIF3A gene, which would be helpful for future risk assessment and personalized treatment of liver diseases.

  10. Hypoxia-inducible factor-1α polymorphisms and TSC1/2 mutations are complementary in head and neck cancers

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    Nikitakis Nikolaos G

    2006-01-01

    Full Text Available Abstract Background Polymorphisms or mutations in hypoxia inducible factor-1 alpha (HIF-1alpha that increases its activity and stability under normoxia have recently been identified. Likewise, disruption of the TSC1/TSC2 complex through loss of TSC1 or TSC2 has been shown to result in abnormal accumulation of HIF-1α. Here, we investigate the novel polymorphisms in exon 12, that approximate the oxygen-dependent degradation domain of HIF-1alpha in five cell lines and 28 patients with oral squamous carcinomas. Moreover, we assess for the presence of polymorphisms and mutations in TSC1 and TSC2, to ascertain if dysregulation of such might complement HIF-1alpha expression. Results Denaturing high pressure liquid chromatography (DHPLC analysis on PCR fragments in exon 12 of HIF-1alpha from 28 patients with OSCC revealed that 6 of 28 patients had mismatched heteroduplex patterns. Genomic DNA was extracted from peripheral blood leukocytes and direct sequencing showed that in 5 of the six cases these changes represented polymorphisms while, one case was a somatic mutation. Analyses of TSC1 and TSC2 revealed heteroduplexes in exons: TSC1 exon 17; TSC2 exons 36,40, and 41. The relative levels of HIF-1alpha were significantly greater for tumors possessing a HIF-1alpha polymorphism or mutation within exon 12, whereas tumors possessing a deletion or polymorphism in TSC1/TSC2 displayed a trend for higher levels of HIF-1alpha. Western blot analyses for HIF-1alpha, TSC1 and TSC2 in five SCC cell lines revealed high levels of HIF-1alpha in SCC cells possessing TSC1 and/or TSC2 mutations. Wild-type TSC2 cells targeted with siRNA to TSC2 exhibited increased levels of HIF-1alpha. Transfection of a HIF-1alpha mutant produced higher levels of HIF-1alpha in TSC1/TSC2 mutant cell lines than in wild type cells. TSC1/TSC2 mutant cell lines administered Rapamycin blocked S6 phorphorylation and diminished the levels of HIF-1alpha to those observed in cell lines with wild

  11. Hypoxia-Inducible Factor Pathway Inhibition Resolves Tumor Hypoxia and Improves Local Tumor Control After Single-Dose Irradiation

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    Helbig, Linda [OncoRay–National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden (Germany); Department of Radiation Oncology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden (Germany); Koi, Lydia [OncoRay–National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden (Germany); Department of Radiation Oncology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden (Germany); Deutsches Konsortium für Translationale Krebsforschung, Site Dresden, Dresden (Germany); Brüchner, Kerstin [Department of Radiation Oncology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden (Germany); Institute of Radiooncology Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Gurtner, Kristin [Department of Radiation Oncology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden (Germany); Hess-Stumpp, Holger; Unterschemmann, Kerstin [Global Drug Discovery, Bayer Pharma, Berlin (Germany); Pruschy, Martin [Radiation Oncology, University of Zurich, Zurich (Switzerland); and others

    2014-01-01

    Purpose: To study the effects of BAY-84-7296, a novel orally bioavailable inhibitor of mitochondrial complex I and hypoxia-inducible factor 1 (HIF-1) activity, on hypoxia, microenvironment, and radiation response of tumors. Methods and Materials: UT-SCC-5 and UT-SCC-14 human squamous cell carcinomas were transplanted subcutaneously in nude mice. When tumors reached 4 mm in diameter BAY-84-7296 (Bayer Pharma AG) or carrier was daily administered to the animals. At 7 mm tumors were either excised for Western blot and immunohistologic investigations or were irradiated with single doses. After irradiation animals were randomized to receive BAY-84-7296 maintenance or carrier. Local tumor control was evaluated 150 days after irradiation, and the dose to control 50% of tumors (TCD{sub 50}) was calculated. Results: BAY-84-7296 decreased nuclear HIF-1α expression. Daily administration of inhibitor for approximately 2 weeks resulted in a marked decrease of pimonidazole hypoxic fraction in UT-SCC-5 (0.5% vs 21%, P<.0001) and in UT-SCC-14 (0.3% vs 19%, P<.0001). This decrease was accompanied by a significant increase in fraction of perfused vessels in UT-SCC-14 but not in UT-SCC-5. Bromodeoxyuridine and Ki67 labeling indices were significantly reduced only in UT-SCC-5. No significant changes were observed in vascular area or necrosis. BAY-84-7296 before single-dose irradiation significantly decreased TCD{sub 50}, with an enhancement ratio of 1.37 (95% confidence interval [CI] 1.13-1.72) in UT-SCC-5 and of 1.55 (95% CI 1.26-1.94) in UT-SCC-14. BAY-84-7296 maintenance after irradiation did not further decrease TCD{sub 50}. Conclusions: BAY-84-7296 resulted in a marked decrease in tumor hypoxia and substantially reduced radioresistance of tumor cells with the capacity to cause a local recurrence after irradiation. The data suggest that reduction of cellular hypoxia tolerance by BAY-84-7296 may represent the primary biological mechanism underlying the observed enhancement of

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

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

    2015-04-03

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

  13. Prostaglandin E2 induces hypoxia-inducible factor-1alpha stabilization and nuclear localization in a human prostate cancer cell line.

    Science.gov (United States)

    Liu, Xin Hua; Kirschenbaum, Alexander; Lu, Min; Yao, Shen; Dosoretz, Amy; Holland, James F; Levine, Alice C

    2002-12-20

    Hypoxia-induced up-regulation of vascular endothelial growth factor (VEGF) expression is a critical event leading to tumor neovascularization. Hypoxia stimulates hypoxia-inducible factor-1alpha (HIF-1alpha), a transcriptional activator of VEGF. Cyclooxygenase (COX)-2, an inducible enzyme that catalyzes the formation of prostaglandins (PGs) from arachidonic acid, is also induced by hypoxia. We reported previously that COX-2 inhibition prevents hypoxic up-regulation of VEGF in human prostate cancer cells and that prostaglandin E(2) (PGE(2)) restores hypoxic effects on VEGF. We hypothesized that PGE(2) mediates hypoxic effects on VEGF by modulating HIF-1alpha expression. Addition of PGE(2) to PC-3ML human prostate cancer cells had no effect on HIF-1alpha mRNA levels. However, PGE(2) significantly increased HIF-1alpha protein levels, particularly in the nucleus. This effect of PGE(2) largely results from the promotion of HIF-1alpha translocation from the cytosol to the nucleus. PGE(2) addition to PC-3 ML cells transfected with a GFP-HIF-1alpha vector induced a time-dependent nuclear accumulation of the HIF-1alpha protein. Two selective COX-2 inhibitors, meloxicam and NS398, decreased HIF-1alpha levels and nuclear localization, under both normoxic and hypoxic conditions. Of several prostaglandins tested, only PGE(2) reversed the effects of a COX-2 inhibitor in hypoxic cells. Finally, PGE(2) effects on HIF-1alpha were specifically inhibited by PD98059 (a MAPK inhibitor). These data demonstrate that PGE(2) production via COX-2-catalyzed pathway plays a critical role in HIF-1alpha regulation by hypoxia and imply that COX-2 inhibitors can prevent hypoxic induction of HIF-mediated gene transcription in cancer cells.

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

    Science.gov (United States)

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

    2014-12-01

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

  15. Hyperplasia and hypertrophy of pulmonary neuroepithelial bodies, presumed airway hypoxia sensors, in hypoxia-inducible factor prolyl hydroxylase-deficient mice.

    Science.gov (United States)

    Pan, Jie; Bishop, Tammie; Ratcliffe, Peter J; Yeger, Herman; Cutz, Ernest

    2016-01-01

    Pulmonary neuroepithelial bodies (NEBs), presumed polymodal airway sensors, consist of innervated clusters of amine (serotonin) and peptide-producing cells. While NEB responses to acute hypoxia are mediated by a membrane-bound O2 sensor complex, responses to sustained and/or chronic hypoxia involve a prolyl hydroxylase (PHD)-hypoxia-inducible factor-dependent mechanism. We have previously reported hyperplasia of NEBs in the lungs of Phd1-/- mice associated with enhanced serotonin secretion. Here we use a novel multilabel immunofluorescence method to assess NEB distribution, frequency, and size, together with the number and size of NEB cell nuclei, and to colocalize multiple cytoplasmic and nuclear epitopes in the lungs of Phd1-/-, Phd2+/-, and Phd3-/- mice and compare them with wild-type controls. To define the mechanisms of NEB cell hyperplasia, we used antibodies against Mash1 and Prox1 (neurogenic genes involved in NEB cell differentiation/maturation), hypoxia-inducible factor-1alpha, and the cell proliferation marker Ki67. Morphometric analysis of (% total lung area) immunostaining for synaptophysin (% synaptophysin), a cytoplasmic marker of NEB cells, was significantly increased in Phd1-/- and Phd3-/- mice compared to wild-type mice. In addition, NEB size and the number and size of NEB nuclei were also significantly increased, indicating that deficiency of Phds is associated with striking hyperplasia and hypertrophy of NEBs. In Phd2+/- mice, while mean % synaptophysin was comparable to wild-type controls, the NEB size was moderately increased, suggesting an effect even in heterozygotes. NEBs in all Phd-deficient mice showed increased expression of Mash1, Prox1, Ki67, and hypoxia-inducible factor-1alpha, in keeping with enhanced differentiation from precursor cells and a minor component of cell proliferation. Since the loss of PHD activity mimics chronic hypoxia, our data provide critical information on the potential role of PHDs in the pathobiology and

  16. Hypoxia-mediated down-regulation of Bid and Bax in tumors occurs via hypoxia-inducible factor 1-dependent and -independent mechanisms and contributes to drug resistance

    DEFF Research Database (Denmark)

    Erler, Janine Terra; Cawthorne, Christopher J; Williams, Kaye J;

    2004-01-01

    of the Bcl-2 protein family. Oxygen deprivation of human colon cancer cells in vitro provoked decreased mRNA and protein levels of proapoptotic Bid and Bad. Hypoxia-inducible factor 1 (HIF-1) was dispensable for the down-regulation of Bad but required for that of Bid, consistent with the binding of HIF-1......alpha to a hypoxia-responsive element (positions -8484 to -8475) in the bid promoter. Oxygen deprivation resulted in proteosome-independent decreased expression of Bax in vitro, consistent with a reduction in global translation efficiency. The physiological relevance of Bid and Bax down...

  17. Transcriptional Regulation of Urokinase-type Plasminogen Activator Receptor by Hypoxia-Inducible Factor 1 Is Crucial for Invasion of Pancreatic and Liver Cancer

    Directory of Open Access Journals (Sweden)

    Peter Büchler

    2009-02-01

    Full Text Available Angioinvasion is critical for metastasis with urokinase-type plasminogen activator receptor (uPAR and tumor hypoxia-activated hypoxia-inducible factor 1 (HIF-1 as key players. Transcriptional control of uPAR expression by HIF has never been reported. The aim of the present study, therefore, was to test whether tumor hypoxia-induced HIF expression may be linked to transcriptional activation of uPAR and dependent angioinvasion. We used human pancreatic cancer cells and a model of parental and derived HIF-1β-deficient mouse liver cancer cell lines and performed Northern blot analysis, nuclear runoff assays, electrophoretic mobility shift assay, polymerase chain reaction-generated deletion mutants, luciferase assays, Matrigel invasion assays, and in vivo angioinvasion assays in the chorioallantoic membrane of fertilized chicken eggs. Urokinase-type plasminogen activator receptor promoter analysis resulted in four putative HIF binding sites. Hypoxia strongly induced de novo transcription of uPAR mRNA. With sequential deletion mutants of the uPAR promoter, it was possible to identify one HIF binding site causing a nearly 200-fold increase in luciferase activity. Hypoxia enhanced the number of invading tumor cells in vitro and in vivo. In contrast, HIF-1β-deficient cells failed to upregulate uPAR expression, to activate luciferase activity, and to invade on hypoxia. Taken together, we show for the first time that uPAR is under transcriptional control of HIF and that this is important for hypoxia-induced metastasis.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-03-01

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

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

    Science.gov (United States)

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

    2017-05-01

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

  20. Mutation of isocitrate dehydrogenase 1 induces glioma cell proliferation via nuclear factor-κB activation in a hypoxia-inducible factor 1-α dependent manner.

    Science.gov (United States)

    Wang, Guoliang; Sai, Ke; Gong, Fanghe; Yang, Qunying; Chen, Furong; Lin, Jian

    2014-05-01

    Recently, mutations of the isocitrate dehydrogenase (IDH) 1 gene, which specifically occur in the majority of low-grade and secondary high-grade gliomas, have drawn particular attention of neuro-oncologists. Mutations of the IDH1 gene have been proposed to have significant roles in the tumorigenesis, progression and prognosis of gliomas. However, the molecular mechanism of the role of IDH1 mutants in gliomagenesis remains to be elucidated. The present study, showed that forced expression of an IDH1 mutant, of which the 132th amino acid residue arginine is substituted by histidine (IDH1R132H), promoted cell proliferation in cultured cells, while wild-type IDH1 overexpression had no effect on cell proliferation. Consistent with previous studies, it was also observed that expression of hypoxia-inducible factor 1-α (HIF1-α) was upregulated in IDH1R132H expressing cells with the induction of vascular endothelial growth factor (VEGF) expression. However, knockdown of VEGF via small RNA interference had no significant influence on the cell proliferation induced by overexpression of IDH1R132H, implying that another signaling pathway may be involved. Next, forced expression of IDH1R132H was found to activate nuclear factor-κB (NF-κB), since the inhibitory IκB protein (IκBα) was highly phosphorylated and the NF-κB p65 subunit was translocated into the nucleus. Notably, knockdown of HIF1-α significantly blocked NF-κB activation, which was induced by the overexpression of IDH1 mutants. In addition, expression of IDH1 mutants markedly induced the NF-κB target gene expression, including cyclin D1 and E and c-myc, which were involved in the regulation of cell proliferation. In conclusion, it was demonstrated that the IDH1 mutant activated NF-κB in a HIF1-α‑dependent manner and was involved in the regulation of cell proliferation.

  1. Ethanol enhances tumor angiogenesis in vitro induced by low-dose arsenic in colon cancer cells through hypoxia-inducible factor 1 alpha pathway.

    Science.gov (United States)

    Wang, Lei; Son, Young-Ok; Ding, Songze; Wang, Xin; Hitron, John Andrew; Budhraja, Amit; Lee, Jeong-Chae; Lin, Qinchen; Poyil, Pratheeshkumar; Zhang, Zhuo; Luo, Jia; Shi, Xianglin

    2012-12-01

    Health effects due to environmental exposure to arsenic are a major global health concern. Arsenic has been known to induce carcinogenesis and enhance tumor development via complex and unclear mechanism. Ethanol is also a well-established risk factor for many malignancies. However, little is known about the effects of coexposure to arsenic and ethanol in tumor development. In this study, we investigate the signaling and angiogenic effect of coexposure of arsenic and ethanol on different colon cancer cell lines. Results show that ethanol markedly enhanced arsenic-induced tumor angiogenesis in vitro. These responses are related to intracellular reactive oxygen species (ROS) generation, NADPH oxidase activation, and upregulation of PI3K/Akt and hypoxia-inducible factor 1 alpha (HIF-1α) signaling. We have also found that ethanol increases the arsenic-induced expression and secretion of angiogenic signaling molecules such as vascular endothelial growth factor, which further confirmed the above observation. Antioxidant enzymes inhibited arsenic/ethanol-induced tumor angiogenesis, demonstrating that the responsive signaling pathways of coexposure to arsenic and ethanol are related to ROS generation. We conclude that ethanol is able to enhance arsenic-induced tumor angiogenesis in colorectal cancer cells via the HIF-1α pathway. These results indicate that alcohol consumption should be taken into consideration in the investigation of arsenic-induced carcinogenesis in arsenic-exposed populations.

  2. Hypoxia induces apelin expression in human adipocytes.

    Science.gov (United States)

    Geiger, K; Muendlein, A; Stark, N; Saely, C H; Wabitsch, M; Fraunberger, P; Drexel, H

    2011-06-01

    Adipokines play a central role in the development of diseases associated with insulin resistance and obesity. Hypoxia in adipose tissue leads to a dysregulation of the expression of adipokines. The effect of hypoxia on the more recently identified adipokine apelin in human adipocytes is unclear. Therefore, we aimed at investigating the role of hypoxia on the expression of the adipokine apelin. Differentiated human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes were cultured under hypoxic conditions for varying time periods. A modular incubator chamber was used to create a hypoxic tissue culture environment (defined as 1% O(2), 94% N, and 5% CO(2)). In addition, hypoxic conditions were mimicked by using CoCl(2). The effect of hypoxia on the expression of the investigated adipokines was measured by real-time PCR and the secretion of apelin was quantified by ELISA. Induction of hypoxia significantly induced mRNA expression of leptin and apelin in differentiated SGBS adipocytes compared with the normoxic control condition. Expression of adiponectin was significantly decreased by hypoxia. In addition, the amount of secreted apelin protein in response to hypoxia was elevated compared to untreated cells. Furthermore, we could demonstrate that the observed hypoxia-induced induction of apelin mRNA expression is in the first phase dependent on HIF-1α. In our study, we could demonstrate for the first time that apelin expression and secretion by human adipocytes are strongly induced under hypoxic conditions and that the early response on hypoxia with apelin induction is dependent on HIF-1α. © Georg Thieme Verlag KG Stuttgart · New York.

  3. 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.

  4. Hypoxia-inducible factor-1 modulates the expression of vascular endothelial growth factor and endothelial nitric oxide synthase induced by eccentric exercise.

    Science.gov (United States)

    Rodriguez-Miguelez, Paula; Lima-Cabello, Elena; Martínez-Flórez, Susana; Almar, Mar; Cuevas, María J; González-Gallego, Javier

    2015-04-15

    The present study investigated the effects of acute and chronic eccentric exercise on the hypoxia-inducible factor (HIF)-1α activation response and the concomitant modulation of vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS) expression in rat skeletal muscle. Twenty-four male Wistar rats were randomly assigned to three experimental groups: rested control group, acutely exercised group after an intermittent downhill protocol for 90 min, and acutely exercise group with a previous eccentric training of 8 wk. HIF-1α activation, VEGF and eNOS gene expression, protein content, and promoter activation were assessed in vastus lateralis muscle biopsies. Acute eccentric exercise induced a marked activation of HIF-1α and resulted in increased VEGF and eNOS mRNA level and protein concentration. The binding of HIF-1α to the VEGF and eNOS promoters, measured by a chromatin immunoprecipitation assay, was undetectable in rested rats, whereas it was evident in acutely exercised animals. Acute exercise also increased myeloperoxidase, toll-like receptor-4, tumor necrosis factor-α, and interleukin-1β protein content, suggesting a contribution of proinflammatory stimuli to HIF-1α activation and VEGF overexpression. All of these effects were partially abolished by training. Moreover, training resulted in an increased capillary density. In summary, our findings indicate that eccentric exercise prompts an HIF-1α response in untrained skeletal muscle that contributes to the upregulation of VEGF and eNOS gene expression and is attenuated after an eccentric training program. Copyright © 2015 the American Physiological Society.

  5. Upregulated copper transporters in hypoxia-induced pulmonary hypertension.

    Directory of Open Access Journals (Sweden)

    Adriana M Zimnicka

    Full Text Available Pulmonary vascular remodeling and increased arterial wall stiffness are two major causes for the elevated pulmonary vascular resistance and pulmonary arterial pressure in patients and animals with pulmonary hypertension. Cellular copper (Cu plays an important role in angiogenesis and extracellular matrix remodeling; increased Cu in vascular smooth muscle cells has been demonstrated to be associated with atherosclerosis and hypertension in animal experiments. In this study, we show that the Cu-uptake transporter 1, CTR1, and the Cu-efflux pump, ATP7A, were both upregulated in the lung tissues and pulmonary arteries of mice with hypoxia-induced pulmonary hypertension. Hypoxia also significantly increased expression and activity of lysyl oxidase (LOX, a Cu-dependent enzyme that causes crosslinks of collagen and elastin in the extracellular matrix. In vitro experiments show that exposure to hypoxia or treatment with cobalt (CoCl2 also increased protein expression of CTR1, ATP7A, and LOX in pulmonary arterial smooth muscle cells (PASMC. In PASMC exposed to hypoxia or treated with CoCl2, we also confirmed that the Cu transport is increased using 64Cu uptake assays. Furthermore, hypoxia increased both cell migration and proliferation in a Cu-dependent manner. Downregulation of hypoxia-inducible factor 1α (HIF-1α with siRNA significantly attenuated hypoxia-mediated upregulation of CTR1 mRNA. In summary, the data from this study indicate that increased Cu transportation due to upregulated CTR1 and ATP7A in pulmonary arteries and PASMC contributes to the development of hypoxia-induced pulmonary hypertension. The increased Cu uptake and elevated ATP7A also facilitate the increase in LOX activity and thus the increase in crosslink of extracellular matrix, and eventually leading to the increase in pulmonary arterial stiffness.

  6. Cobalt chloride decreases fibroblast growth factor-21 expression dependent on oxidative stress but not hypoxia-inducible factor in Caco-2 cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yanlong [School of Pharmacy, Wenzhou Medical College, Wenzhou (China); Department of Medicine, University of Louisville, Louisville, KY (United States); Wang, Chunhong [Second Hospital, Jilin University, Changchun (China); Department of Medicine, University of Louisville, Louisville, KY (United States); Wang, Yuhua [College of Food Science and Engineering, Jilin Agricultural University, Changchun (China); Department of Medicine, University of Louisville, Louisville, KY (United States); Ma, Zhenhua [First Hospital, Xi' an Jiaotong University, Xi' an (China); Department of Medicine, University of Louisville, Louisville, KY (United States); Xiao, Jian [School of Pharmacy, Wenzhou Medical College, Wenzhou (China); McClain, Craig [Department of Medicine, University of Louisville, Louisville, KY (United States); Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY (United States); Alcohol Research Center, University of Louisville, Louisville, KY (United States); Robley Rex Veterans Affairs Medical Center, Louisville, KY (United States); Li, Xiaokun [School of Pharmacy, Wenzhou Medical College, Wenzhou (China); Feng, Wenke, E-mail: wenke.feng@louisville.edu [School of Pharmacy, Wenzhou Medical College, Wenzhou (China); Department of Medicine, University of Louisville, Louisville, KY (United States); Alcohol Research Center, University of Louisville, Louisville, KY (United States)

    2012-10-15

    Fibroblast growth factor-21 (FGF21) is a potential metabolic regulator with multiple beneficial effects on metabolic diseases. FGF21 is mainly expressed in the liver, but is also found in other tissues including the intestine, which expresses β-klotho abundantly. The intestine is a unique organ that operates in a physiologically hypoxic environment, and is responsible for the fat absorption processes including triglyceride breakdown, re-synthesis and absorption into the portal circulation. In the present study, we investigated the effects of hypoxia and the chemical hypoxia inducer, cobalt chloride (CoCl{sub 2}), on FGF21 expression in Caco-2 cells and the consequence of fat accumulation. Physical hypoxia (1% oxygen) and CoCl{sub 2} treatment decreased both FGF21 mRNA and secreted protein levels. Gene silence and inhibition of hypoxia-inducible factor-α (HIFα) did not affect the reduction of FGF21 mRNA and protein levels by hypoxia. However, CoCl{sub 2} administration caused a significant increase in oxidative stress. The addition of n-acetylcysteine (NAC) suppressed CoCl{sub 2}-induced reactive oxygen species (ROS) formation and completely negated CoCl{sub 2}-induced FGF21 loss. mRNA stability analysis demonstrated that the CoCl{sub 2} administration caused a remarkable reduction in FGF21 mRNA stability. Furthermore, CoCl{sub 2} increased intracellular triglyceride (TG) accumulation, along with a reduction in mRNA levels of lipid lipase, hormone sensitive lipase (HSL) and adipose triglyceride lipase (ATGL), and an increase of sterol regulatory element-binding protein-1c (SREBP1c) and stearoyl-coenzyme A (SCD1). Addition of both NAC and recombinant FGF21 significantly attenuated the CoCl{sub 2}-induced TG accumulation. In conclusion, the decrease of FGF21 in Caco-2 cells by chemical hypoxia is independent of HIFα, but dependent on an oxidative stress-mediated mechanism. The regulation of FGF21 by hypoxia may contribute to intestinal lipid metabolism and

  7. Quercetin induces protective autophagy in gastric cancer cells: involvement of Akt-mTOR- and hypoxia-induced factor 1α-mediated signaling.

    Science.gov (United States)

    Wang, Kui; Liu, Rui; Li, Jingyi; Mao, Jiali; Lei, Yunlong; Wu, Jinhua; Zeng, Jun; Zhang, Tao; Wu, Hong; Chen, Lijuan; Huang, Canhua; Wei, Yuquan

    2011-09-01

    Quercetin, a dietary antioxidant present in fruits and vegetables, is a promising cancer chemopreventive agent that inhibits tumor promotion by inducing cell cycle arrest and promoting apoptotic cell death. In this study, we examined the biological activities of quercetin against gastric cancer. Our studies demonstrated that exposure of gastric cancer cells AGS and MKN28 to quercetin resulted in pronounced pro-apoptotic effect through activating the mitochondria pathway. Meanwhile, treatment with quercetin induced appearance of autophagic vacuoles, formation of acidic vesicular organelles (AVOs), conversion of LC3-I to LC3-II, recruitment of LC3-II to the autophagosomes as well as activation of autophagy genes, suggesting that quercetin initiates the autophagic progression in gastric cancer cells. Furthermore, either administration of autophagic inhibitor chloroquine or selective ablation of atg5 or beclin 1 using small interfering RNA (siRNA) could augment quercetin-induced apoptotic cell death, suggesting that autophagy plays a protective role against quercetin-induced apoptosis. Moreover, functional studies revealed that quercetin activated autophagy by modulation of Akt-mTOR signaling and hypoxia-induced factor 1α (HIF-1α) signaling. Finally, a xenograft model provided additional evidence for occurrence of quercetin-induced apoptosis and autophagy in vivo. Together, our studies provided new insights regarding the biological and anti-proliferative activities of quercetin against gastric cancer, and may contribute to rational utility and pharmacological study of quercetin in future anti-cancer research.

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

    Directory of Open Access Journals (Sweden)

    Wei-Ming Wang

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

  9. Hypoxia-inducible factor-1α is involved in isoflurane-induced blood-brain barrier disruption in aged rats model of POCD.

    Science.gov (United States)

    Cao, Yiyun; Li, Zhengqian; Li, Hongping; Ni, Cheng; Li, Lunxu; Yang, Ning; Shi, Chengmei; Zhong, Yanfeng; Cui, Dehua; Guo, Xiangyang

    2017-09-05

    Prolonged exposure to inhaled anesthetics may lead to postoperative cognitive dysfunction (POCD). Nevertheless, the underlying mechanisms are not known. Hypoxia-inducible factor-1α (HIF-1α) and its target gene vascular endothelial growth factor (VEGF) were shown to be activated by inhaled anesthetics. The aim of the present study was to determine the role of HIF-1α in isoflurane-induced blood-brain barrier (BBB) disruption and resultant cognitive impairment. After a 4-h exposure to 1.5% isoflurane in 20-month-old rats, increases in vascular permeability, and disrupted BBB ultrastructure were accompanied by the degradation of tight junction proteins occludin and collagen type IV in brain blood vessels. Increases in HIF-1α and VEGF proteins and activation of MMP-2 in the hippocampus were also observed in the hippocamp of isoflurane-exposed rats compared with control rats. Pharmacological inhibition of HIF-1α activation by 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole (YC-1) markedly suppressed the expression of HIF-1α, VEGF and MMP-2, and mitigated the severity of BBB disruption.YC-1 pretreatment also significantly attenuated isoflurane-induced cognitive deficits in the Morris water maze task. Overall, our results demonstrate that hippocampal HIF-1α/VEGF signaling seems to be the upstream mechanism of isoflurane-induced cognitive impairment, and provides apotential preventive and therapeutic target for POCD. Copyright © 2017. Published by Elsevier B.V.

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

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    Duohong Zou

    2011-07-01

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

  11. Expression of hypoxia inducible factor-1 alpha and ischemic erythropoietin tolerance in the brain of cerebral ischemic tolerance model rats

    Institute of Scientific and Technical Information of China (English)

    Renliang Zhao; Ruijian Dong; Zhongling Sun

    2006-01-01

    BACKGROUND: Hypoxia inducible factor-1 alpha (HIF-1 α) and erythropoietin(EPO), possessing neuroprotective effect in the cerebral ischemia, might play an important role in the formation of cerebral ischemic tolerance (IT).OBJECTIVE:To observe the neuroprotective effect of cerebral ischemic preconditioning(IPC) of rats, and the expression and mechanism of HIF-1α and target gene erythropoietin in the brain tissue following the formation of cerebral IT.DESIGN :A randomized and controlled observation.SETTING: Department of Neurology, the Affiliated Hospital of Medical College, Qingdao University.MATERIALS: Totally 84 enrolled adult healthy male Wistar rats of clean grade, weighing 250 to 300 g, were provided by the Animal Experimental Department, Tongji Medical College of Huazhong University of Science and Technology. Ready-to-use SABC reagent kit and rabbit anti-rat HIF-1α monoclonal antibody were purchased from Boshide Bioengineering Co. Ltd (Wuhan); Rabbit anti-rat EPO monoclonal antibody was purchased from Santa Cruz Company (USA).METHODS: This experiment was carried out in the Department of Anatomy, Medical College, Qingdao University during March 2005 to March 2006. ① The 84 rats were divided into 3 groups by a lot: IPC group (n=40),sham-operation group (n=40) and control group (n=4). In the IPC group, middle cerebral artery was occluded for 2 hours respectively on the 1st, 3rd, 7th, 14th and 21st days of the reperfusion following 10-minute preischemia was made using a modified middle cerebral artery second suture method from Zea-Longa. The rats were sacrificed 22 hours after reperfusion in the end of middle cerebral artery occlusion (MCAO). That was to say,after 10-minute preischemia, suture was exited to the external carotid artery and embedded subcutaneously.Middle cerebral artery was occluded again to form the second reperfusion at the set time point after reperfusion. Twenty-two hours later, rats were sacrificed; In the sham-operation group

  12. Potent and Selective Triazole-Based Inhibitors of the Hypoxia-Inducible Factor Prolyl-Hydroxylases with Activity in the Murine Brain

    Science.gov (United States)

    Chan, Mun Chiang; Atasoylu, Onur; Hodson, Emma; Tumber, Anthony; Leung, Ivanhoe K. H.; Chowdhury, Rasheduzzaman; Gómez-Pérez, Verónica; Demetriades, Marina; Rydzik, Anna M.; Holt-Martyn, James; Tian, Ya-Min; Bishop, Tammie; Claridge, Timothy D. W.; Kawamura, Akane; Pugh, Christopher W.; Ratcliffe, Peter J.; Schofield, Christopher J.

    2015-01-01

    As part of the cellular adaptation to limiting oxygen availability in animals, the expression of a large set of genes is activated by the upregulation of the hypoxia-inducible transcription factors (HIFs). Therapeutic activation of the natural human hypoxic response can be achieved by the inhibition of the hypoxia sensors for the HIF system, i.e. the HIF prolyl-hydroxylases (PHDs). Here, we report studies on tricyclic triazole-containing compounds as potent and selective PHD inhibitors which compete with the 2-oxoglutarate co-substrate. One compound (IOX4) induces HIFα in cells and in wildtype mice with marked induction in the brain tissue, revealing that it is useful for studies aimed at validating the upregulation of HIF for treatment of cerebral diseases including stroke. PMID:26147748

  13. Potent and Selective Triazole-Based Inhibitors of the Hypoxia-Inducible Factor Prolyl-Hydroxylases with Activity in the Murine Brain.

    Directory of Open Access Journals (Sweden)

    Mun Chiang Chan

    Full Text Available As part of the cellular adaptation to limiting oxygen availability in animals, the expression of a large set of genes is activated by the upregulation of the hypoxia-inducible transcription factors (HIFs. Therapeutic activation of the natural human hypoxic response can be achieved by the inhibition of the hypoxia sensors for the HIF system, i.e. the HIF prolyl-hydroxylases (PHDs. Here, we report studies on tricyclic triazole-containing compounds as potent and selective PHD inhibitors which compete with the 2-oxoglutarate co-substrate. One compound (IOX4 induces HIFα in cells and in wildtype mice with marked induction in the brain tissue, revealing that it is useful for studies aimed at validating the upregulation of HIF for treatment of cerebral diseases including stroke.

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

    Science.gov (United States)

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

    2017-08-01

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

  15. Silencing of osteopontin promotes the radiosensitivity of breast cancer cells by reducing the expression of hypoxia inducible factor 1 and vascular endothelial growth factor

    Institute of Scientific and Technical Information of China (English)

    YANG Li; ZHAO Wei; ZUO Wen-shu; WEI Ling; SONG Xian-rang; WANG Xing-wu; ZHENG Gang; ZHENG Mei-zhu

    2012-01-01

    Background Osteopontin (OPN) is a secreted phosphoglycoprotein (SSP) that is overexpressed in a variety of tumors and was regarded as a molecular marker of tumors.In this study,we intended to demonstrate the role of OPN in human breast cancer cell line MDA-MB-231.Methods Recombinant plasmid expressing small interfering RNA (siRNA) specific to OPN mRNA was transfected into MDA-MB-231 cells to generate the stable transfected cell line MDA-MB-343,and the empty plasmid tansfected cells (MDA-MB-neg) or wildtype MDA-MB-231 cells were used as control cells respectively.Expression of OPN,hypoxia inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) proteins was analyzed by Western blotting analysis.The radiosensitivity of cells was determined by detecting cell apoptosis,cell proliferation and cell senescence.Results HIF-1 and VEGF proteins in MDA-MB-343 cells were significantly downregulated upon the efficient knockdown of OPN expression under either hypoxia or normoxia environment.Moreover,expression of OPN protein was upregualted upon hypoxic culture.Stable OPN-silencing also decreased cell invasion,increased cell apoptosis and cell senescence,as well as reduced clonogenic survival,resulting in increase radiation tolerance.Conclusions Suppression of OPN gene expression can enhance radiosensitivity and affect cell apoptosis in breast cancer cells.OPN seems to be an attractive target for the improvement of radiotherapy.

  16. Is the hypoxia-inducible factor-1 alpha mRNA expression activated by ethanol-induced injury, the mechanism underlying alcoholic liver disease?

    Institute of Scientific and Technical Information of China (English)

    Lin Li; Shao-Hua Chen; Yu Zhang; Chao-Hui Yu; Shu-Dan Li; You-Ming Li

    2006-01-01

    BACKGROUND: Excessive alcohol consumption can result in multiple organ injury, of which alcoholic liver disease (ALD) is the most common. With economic development and improvement of living standards, the incidence of diseases caused by alcohol abuse has been increasing in China, although its pathogenesis remains obscure. The aim of this study was to investigate the role of hypoxia in chronic ALD. METHODS:Twenty-eight male Sprague-Dawley rats were randomized into a control group (n=12) with a normal history and an experimental group (n=16) fed with 10 ml/kg of 56%(vol/vol) ethanol once per day by gastric lavage for 24 weeks. At 24 weeks, blood samples were collected and then the rats were killed. Liver samples were frozen at-80 ℃and used for RT-PCR;other liver samples were obtained for immunohistochemical staining. RESULTS:When the period of alcohol consumption increased, the positive rate of expression of hypoxia-inducible factor-1 alpha (HIF-1α) mRNA was more signiifcantly elevated in the liver of the alcohol group than in the control group (P≤0.05). The HIF-1αprotein located in the cytoplasm was seldom expressed in the control group, but signiifcantly in the alcohol group (P≤0.01). CONCLUSION: HIF-1α mRNA expression was activated by ethanol-induced injury in this study, suggesting that hypoxia is involved in the underlying mechanism of ALD.

  17. Hypoxia-inducible factor-1α increased the expression of peroxisome proliferator activated receptor α in lung cancer cell A549

    Institute of Scientific and Technical Information of China (English)

    张惠兰; 张珍祥; 徐永健

    2004-01-01

    @@ Hypoxia plays a fundamental role in many pathologic processes. Hypoxia-inducible factor-1 (HIF-1) is a heterodimeric basic helix-loop-helix-per-aryl hydrocarbon receptor ARNT-sim (PAS) domain protein, consisting of α and β subunits and is precisely regulated by cellular oxygen levels.1 The peroxisome proliferator-activated receptors (PPARs) are family nuclear hormone-binding proteins with increasing diverse functions as transcriptional regulators, owning three subtypes (α, β, and γ).2 PPARα plays a critical physiological role as lipid sensors and regulators of proliferation.3 Hypoxia can elicit up-regulation of PPAR-α expression.4 Herein, we report the results of an investigation on the correlation of HIF-1α and PPARα.

  18. Reversion of lethality and growth defects in Fatiga oxygen-sensor mutant flies by loss of Hypoxia-Inducible Factor-α/Sima

    Science.gov (United States)

    Centanin, Lázaro; Ratcliffe, Peter J; Wappner, Pablo

    2005-01-01

    Hypoxia-Inducible Factor (HIF) prolyl hydroxylase domains (PHDs) have been proposed to act as sensors that have an important role in oxygen homeostasis. In the presence of oxygen, they hydroxylate two specific prolyl residues in HIF-α polypeptides, thereby promoting their proteasomal degradation. So far, however, the developmental consequences of the inactivation of PHDs in higher metazoans have not been reported. Here, we describe novel loss-of-function mutants of fatiga, the gene encoding the Drosophila PHD oxygen sensor, which manifest growth defects and lethality. We also report a null mutation in dHIF-α/sima, which is unable to adapt to hypoxia but is fully viable in normoxic conditions. Strikingly, loss-of-function mutations of sima rescued the developmental defects observed in fatiga mutants and enabled survival to adulthood. These results indicate that the main functions of Fatiga in development, including control of cell size, involve the regulation of dHIF/Sima. PMID:16179946

  19. Reversion of lethality and growth defects in Fatiga oxygen-sensor mutant flies by loss of hypoxia-inducible factor-alpha/Sima.

    Science.gov (United States)

    Centanin, Lázaro; Ratcliffe, Peter J; Wappner, Pablo

    2005-11-01

    Hypoxia-Inducible Factor (HIF) prolyl hydroxylase domains (PHDs) have been proposed to act as sensors that have an important role in oxygen homeostasis. In the presence of oxygen, they hydroxylate two specific prolyl residues in HIF-alpha polypeptides, thereby promoting their proteasomal degradation. So far, however, the developmental consequences of the inactivation of PHDs in higher metazoans have not been reported. Here, we describe novel loss-of-function mutants of fatiga, the gene encoding the Drosophila PHD oxygen sensor, which manifest growth defects and lethality. We also report a null mutation in dHIF-alpha/sima, which is unable to adapt to hypoxia but is fully viable in normoxic conditions. Strikingly, loss-of-function mutations of sima rescued the developmental defects observed in fatiga mutants and enabled survival to adulthood. These results indicate that the main functions of Fatiga in development, including control of cell size, involve the regulation of dHIF/Sima.

  20. Adipocyte-Specific Hypoxia-Inducible Factor 2α Deficiency Exacerbates Obesity-Induced Brown Adipose Tissue Dysfunction and Metabolic Dysregulation.

    Science.gov (United States)

    García-Martín, Rubén; Alexaki, Vasileia I; Qin, Nan; Rubín de Celis, María F; Economopoulou, Matina; Ziogas, Athanasios; Gercken, Bettina; Kotlabova, Klara; Phieler, Julia; Ehrhart-Bornstein, Monika; Bornstein, Stefan R; Eisenhofer, Graeme; Breier, Georg; Blüher, Matthias; Hampe, Jochen; El-Armouche, Ali; Chatzigeorgiou, Antonios; Chung, Kyoung-Jin; Chavakis, Triantafyllos

    2015-11-16

    Angiogenesis is a central regulator for white (WAT) and brown (BAT) adipose tissue adaptation in the course of obesity. Here we show that deletion of hypoxia-inducible factor 2α (HIF2α) in adipocytes (by using Fabp4-Cre transgenic mice) but not in myeloid or endothelial cells negatively impacted WAT angiogenesis and promoted WAT inflammation, WAT dysfunction, hepatosteatosis, and systemic insulin resistance in obesity. Importantly, adipocyte HIF2α regulated vascular endothelial growth factor (VEGF) expression and angiogenesis of obese BAT as well as its thermogenic function. Consistently, obese adipocyte-specific HIF2α-deficient mice displayed BAT dysregulation, associated with reduced levels of uncoupling protein 1 (UCP1) and a dysfunctional thermogenic response to cold exposure. VEGF administration reversed WAT and BAT inflammation and BAT dysfunction in adipocyte HIF2α-deficient mice. Together, our findings show that adipocyte HIF2α is protective against maladaptation to obesity and metabolic dysregulation by promoting angiogenesis in both WAT and BAT and by counteracting obesity-mediated BAT dysfunction. Copyright © 2016 García-Martín et al.

  1. 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.

  2. LXY6090 – a novel manassantin A derivative – limits breast cancer growth through hypoxia-inducible factor-1 inhibition

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    Lai F

    2016-06-01

    Full Text Available Fangfang Lai,1 Qian Liu,2 Xiaoyu Liu,3 Ming Ji,1 Ping Xie,3 Xiaoguang Chen1 1Department of Pharmacology, State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, 2Department of Pharmacology, National Institutes for Food and Drug Control, 3Department of Pharmacochemistry, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of China Abstract: Hypoxia-inducible factor-1 (HIF-1 represents a novel antitumor target owing to its involvement in vital processes considered hallmarks of cancer phenotypes. Manassantin A (MA derived from Saururus cernuus has been reported as a selective HIF-1 inhibitor. Herein, the structure of MA was optimized to achieve new derivatives with simple chemical properties while retaining its activity. LXY6090 was designed to replace the central tetrahydrofuran moiety of MA with a cyclopentane ring and was identified as a potent HIF-1 inhibitor with an IC50 value of 4.11 nM. It not only inhibited the activity of HIF-1 in breast cancer cells but also downregulated the protein level of HIF-1α, which depended on von Hippel–Lindau for proteasome degradation. The related biological evaluation showed that the activity of HIF-1 target genes, VEGF and IGF-2, was decreased by LXY6090 in breast cancer cell lines. LXY6090 presented potent antitumor activity in vitro. Furthermore, LXY6090 showed in vivo anticancer efficacy by decreasing the HIF-1α expression in nude mice bearing MX-1 tumor xenografts. In conclusion, our data provide a basis for the future development of the novel compound LXY6090 as a potential therapeutic agent for breast cancer. Keywords: hypoxia-inducible factor-1, manassantin A derivative, antitumor, breast cancer, LXY6090

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

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    Tanya L Medley

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

  4. Bacterial siderophores that evade or overwhelm lipocalin 2 induce hypoxia inducible factor 1α and proinflammatory cytokine secretion in cultured respiratory epithelial cells.

    Science.gov (United States)

    Holden, Victoria I; Lenio, Steven; Kuick, Rork; Ramakrishnan, Sadeesh K; Shah, Yatrik M; Bachman, Michael A

    2014-09-01

    Iron is essential for many cellular processes and is required by bacteria for replication. To acquire iron from the host, pathogenic Gram-negative bacteria secrete siderophores, including enterobactin (Ent). However, Ent is bound by the host protein lipocalin 2 (Lcn2), preventing bacterial reuptake of aferric or ferric Ent. Furthermore, the combination of Ent and Lcn2 (Ent+Lcn2) leads to enhanced secretion of interleukin-8 (IL-8) compared to that induced by either stimulus alone. Modified or structurally distinct siderophores, including yersiniabactin (Ybt) and glycosylated Ent (GlyEnt, or salmochelin), deliver iron to bacteria despite the presence of Lcn2. We hypothesized that the robust immune response to Ent and Lcn2 requires iron chelation rather than the Ent+Lcn2 complex itself and also can be stimulated by Lcn2-evasive siderophores. To test this hypothesis, cultured respiratory epithelial cells were stimulated with combinations of purified siderophores and Lcn2 and analyzed by gene expression microarrays, quantitative PCR, and cytokine immunoassays. Ent caused HIF-1α protein stabilization, induced the expression of genes regulated by hypoxia-inducible factor 1α (HIF-1α), and repressed genes involved in cell cycle and DNA replication, whereas Lcn2 induced expression of proinflammatory cytokines. Iron chelation by excess Ent or Ybt significantly increased Lcn2-induced secretion of IL-8, IL-6, and CCL20. Stabilization of HIF-1α was sufficient to enhance Lcn2-induced IL-6 secretion. These data indicate that respiratory epithelial cells can respond to bacterial siderophores that evade or overwhelm Lcn2 binding by increasing proinflammatory cytokine production.

  5. Gefitinib circumvents hypoxia-induced drug resistance by the modulation of HIF-1alpha.

    Science.gov (United States)

    Rho, Jin Kyung; Choi, Yun Jung; Lee, Jin Kyung; Ryoo, Baek-Yeol; Na, Im Ii; Yang, Sung Hyun; Kim, Cheol Hyeon; Yoo, Young Do; Lee, Jae Cheol

    2009-03-01

    Hypoxia-inducible factor-1alpha (HIF-1alpha) is a transcriptional factor which is activated by hypoxia and associated with cell survival, proliferation and drug resistance. Recent studies have shown that the down-stream molecules of the epidermal growth factor receptor (EGFR) signal are involved in the hypoxia-dependent or -independent HIF-1alpha protein accumulation. Thus, we hypothesized that an EGFR-TK inhibitor, gefitinib, might circumvent the hypoxia-induced drug resistance via the regulation of HIF-1alpha expression. In our data, treatment of gefitinib suppressed induced HIF-1alpha by hypoxia. This action of gefitinib was caused by reduced protein stability without any change in the level of HIF-1alpha mRNA. The effect of gefitinib on down-regulation of HIF-1alpha was reversed by transfection of constitutively active form of Akt. The cellular response to gefitinib was similar in both normoxia and hypoxia condition. However, the response to conventional chemotherapeutic drugs decreased >50% under hypoxia condition and they did not change HIF-1alpha expression. In addition, the suppression of HIF-1alpha using siRNA overcame partially hypoxia-induced drug resistance. In conclusion, gefitinib was able to circumvent hypoxia-induced drug resistance suggesting that the effective suppression of HIF-1alpha by the inhibition of EGFR-Akt pathway may overcome the hypoxia-induced drug resistance.

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

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

    2014-11-15

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

  7. Loss of hypoxia-inducible factor 2 alpha in the lung alveolar epithelium of mice leads to enhanced eosinophilic inflammation in cobalt-induced lung injury.

    Science.gov (United States)

    Proper, Steven P; Saini, Yogesh; Greenwood, Krista K; Bramble, Lori A; Downing, Nathaniel J; Harkema, Jack R; Lapres, John J

    2014-02-01

    Hard metal lung disease (HMLD) is an occupational lung disease specific to inhalation of cobalt-containing particles whose mechanism is largely unknown. Cobalt is a known hypoxia mimic and stabilizer of the alpha subunits of hypoxia-inducible factors (HIFs). Previous work revealed that though HIF1α contrib utes to cobalt toxicity in vitro, loss of HIF1α in the alveolar epithelial cells does not provide in vivo protection from cobalt-induced lung inflammation. HIF1α and HIF2α show unique tissue expression profiles, and HIF2α is known to be the predominant HIF mRNA isoform in the adult lung. Thus, if HIF2α activation by cobalt contributes to pathophysiology of HMLD, we hypothesized that loss of HIF2α in lung epithelium would provide protection from cobalt-induced inflammation. Mice with HIF2α-deficiency in Club and alveolar type II epithelial cells (ATIIs) (HIF2α(Δ/Δ)) were exposed to cobalt (60 µg/day) or saline using a subacute occupational exposure model. Bronchoalveolar lavage cellularity, cytokines, qRT-PCR, and histopathology were analyzed. Results show that loss of HIF2α leads to enhanced eosinophilic inflammation and increased goblet cell metaplasia. Additionally, control mice demonstrated a mild recovery from cobalt-induced lung injury compared with HIF2α(Δ/Δ) mice, suggesting a role for epithelial HIF2α in repair mechanisms. The expression of important cytokines, such as interleukin (IL)-5 and IL-10, displayed significant differences following cobalt exposure when HIF2α(Δ/Δ) and control mice were compared. In summary, our data suggest that although loss of HIF2α does not afford protection from cobalt-induced lung inflammation, epithelial HIF2α signaling does play an important role in modulating the inflammatory and repair response in the lung.

  8. Loss of Hypoxia-Inducible Factor 2 Alpha in the Lung Alveolar Epithelium of Mice Leads to Enhanced Eosinophilic Inflammation in Cobalt-Induced Lung Injury

    Science.gov (United States)

    Proper, Steven P.; Saini, Yogesh; LaPres, John J.

    2014-01-01

    Hard metal lung disease (HMLD) is an occupational lung disease specific to inhalation of cobalt-containing particles whose mechanism is largely unknown. Cobalt is a known hypoxia mimic and stabilizer of the alpha subunits of hypoxia-inducible factors (HIFs). Previous work revealed that though HIF1α contrib utes to cobalt toxicity in vitro, loss of HIF1α in the alveolar epithelial cells does not provide in vivo protection from cobalt-induced lung inflammation. HIF1α and HIF2α show unique tissue expression profiles, and HIF2α is known to be the predominant HIF mRNA isoform in the adult lung. Thus, if HIF2α activation by cobalt contributes to pathophysiology of HMLD, we hypothesized that loss of HIF2α in lung epithelium would provide protection from cobalt-induced inflammation. Mice with HIF2α-deficiency in Club and alveolar type II epithelial cells (ATIIs) (HIF2αΔ/Δ) were exposed to cobalt (60 µg/day) or saline using a subacute occupational exposure model. Bronchoalveolar lavage cellularity, cytokines, qRT-PCR, and histopathology were analyzed. Results show that loss of HIF2α leads to enhanced eosinophilic inflammation and increased goblet cell metaplasia. Additionally, control mice demonstrated a mild recovery from cobalt-induced lung injury compared with HIF2αΔ/Δ mice, suggesting a role for epithelial HIF2α in repair mechanisms. The expression of important cytokines, such as interleukin (IL)-5 and IL-10, displayed significant differences following cobalt exposure when HIF2αΔ/Δ and control mice were compared. In summary, our data suggest that although loss of HIF2α does not afford protection from cobalt-induced lung inflammation, epithelial HIF2α signaling does play an important role in modulating the inflammatory and repair response in the lung. PMID:24218148

  9. Ferritin-Mediated Iron Sequestration Stabilizes Hypoxia-Inducible Factor-1α upon LPS Activation in the Presence of Ample Oxygen

    Directory of Open Access Journals (Sweden)

    Isabel Siegert

    2015-12-01

    Full Text Available Both hypoxic and inflammatory conditions activate transcription factors such as hypoxia-inducible factor (HIF-1α and nuclear factor (NF-κB, which play a crucial role in adaptive responses to these challenges. In dendritic cells (DC, lipopolysaccharide (LPS-induced HIF1α accumulation requires NF-κB signaling and promotes inflammatory DC function. The mechanisms that drive LPS-induced HIF1α accumulation under normoxia are unclear. Here, we demonstrate that LPS inhibits prolyl hydroxylase domain enzyme (PHD activity and thereby blocks HIF1α degradation. Of note, LPS-induced PHD inhibition was neither due to cosubstrate depletion (oxygen or α-ketoglutarate nor due to increased levels of reactive oxygen species, fumarate, and succinate. Instead, LPS inhibited PHD activity through NF-κB-mediated induction of the iron storage protein ferritin and subsequent decrease of intracellular available iron, a critical cofactor of PHD. Thus, hypoxia and LPS both induce HIF1α accumulation via PHD inhibition but deploy distinct molecular mechanisms (lack of cosubstrate oxygen versus deprivation of co-factor iron.

  10. Hypoxia-induced down-modulation of PKCepsilon promotes trail-mediated apoptosis of tumor cells.

    Science.gov (United States)

    Gobbi, Giuliana; Masselli, Elena; Micheloni, Cristina; Nouvenne, Antonio; Russo, Domenico; Santi, Patrizia; Matteucci, Alessandro; Cocco, Lucio; Vitale, Marco; Mirandola, Prisco

    2010-09-01

    Tumor oxygen status is considered as a prognostic marker that impacts on malignant progression and outcome of tumor therapy. TNF-related apoptosis inducing ligand (TRAIL) plays a key role in cancer immunity, with potential applications in cancer therapy. Protein kinase C (PKC)epsilon, a transforming oncogene, has a role in the protection of cardiomyocytes and neurons from hypoxia-induced damage while, it can also modulate the susceptibility of tumor cells to TRAIL-induced cell death. Here we demonstrate that hypoxia induces a tumor cell phenotype highly sensitive to the cytotoxic effects of TRAIL. Based on the observation that: i) PKCepsilon expression levels are impaired during hypoxia, ii) the overexpression of PKCepsilon, but not of a kinase-inactive PKCepsilon mutant, is able to revert the hypoxia-induced sensitivity to TRAIL, iii) the down-modulation of PKCepsilon levels by RNA interference, on the contrary, induces the highly TRAIL-sensitive phenotype, iv) the inhibition of hypoxia-inducible transcription factor-1alpha (HIF-1alpha) by specific siRNA blocks both the hypoxia-induced down-modulation of PKCepsilon and the induction of the highly TRAIL-sensitive phenotype; we conclude that the HIF-1alpha upregulation during hypoxia is associated to PKCepsilon down-modulation that likely represents the key molecular event promoting the apoptogenic effects of TRAIL in hypoxic tumor cells.

  11. Hypoxia-inducible factor-1 alpha, in association with inflammation, angiogenesis and MYC, is a critical prognostic factor in patients with HCC after surgery

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    Zhou Jian

    2009-12-01

    Full Text Available Abstract Background Despite well-studied tumor hypoxia in laboratory, little is known about the association with other pathophysiological events in the clinical view. We investigated the prognostic value of hypoxia-inducible factor-1 alpha (HIF-1alpha in hepatocellular carcinoma (HCC, and its correlations with inflammation, angiogenesis and MYC oncogene. Methods In a random series of 110 HCC patients, the mRNA of HIF-1alpha, inflammation related factors (COX-2, MMP7 and MMP9, angiogenesis related factors (VEGF and PDGFRA and MYC in tumor tissue were detected by real-time RT-PCR and HIF-1alpha protein was assessed by immunohistochemistry. The correlations between HIF-1alpha mRNA and the factors mentioned previously, the relationship between HIF-1alpha and clinicopathologic features, and the prognostic value were analyzed. Results The expression of both HIF-1alpha mRNA and protein in HCC were independent prognostic factors for overall survival (OS (P = 0.012 and P = 0.021, respectively and disease-free survival (DFS (P = 0.004 and P = 0.007, respectively as well. Besides, the high expression of HIF-1alpha mRNA and protein proposed an advanced BCLC stage and more incidence of vascular invasion. The mRNA of HIF-1alpha had significantly positive correlations to that of COX-2, PDGFRA, MMP7, MMP9, MYC, except VEGF. In addition to HIF-1alpha, COX-2 and PDGFRA were also independent prognosticators for OS (P = 0.004 and P = 0.010, respectively and DFS (P = 0.010 and P = 0.038, respectively. Conclusion HIF-1alpha in HCC plays an important role in predicting patient outcome. It may influence HCC biological behaviors and affect the tumor inflammation, angiogenesis and act in concert with the oncogene MYC. Attaching importance to HIF-1alpha in HCC may improve the prognostic and therapeutic technique.

  12. Hypoxia-induced retinopathy model in adult zebrafish

    DEFF Research Database (Denmark)

    Cao, Ziquan; Jensen, Lasse D.; Rouhi, Pegah;

    2010-01-01

    . In this article, we describe protocols that create hypoxia-induced retinopathy in adult zebrafish. Adult fli1: EGFP zebrafish are placed in hypoxic water for 3-10 d and retinal neovascularization is analyzed using confocal microscopy. It usually takes 11 d to obtain conclusive results using the hypoxia...

  13. Screening of hypoxia-inducible genes in sporadic ALS.

    LENUS (Irish Health Repository)

    Cronin, Simon

    2008-10-01

    Genetic variations in two hypoxia-inducible angiogenic genes, VEGF and ANG, have been linked with sporadic amyotrophic lateral sclerosis (SALS). Common variations in these genes may reduce the levels or functioning of their products. VEGF and ANG belong to a larger group of angiogenic genes that are up-regulated under hypoxic conditions. We hypothesized that common genetic variation across other members of this group may also predispose to sporadic ALS. To screen other hypoxia-inducible angiogenic genes for association with SALS, we selected 112 tagging single nucleotide polymorphisms (tgSNPs) that captured the common genetic variation across 16 VEGF-like and eight ANG-like hypoxia-inducible genes. Screening for association was performed in 270 Irish individuals with typical SALS and 272 ethnically matched unrelated controls. SNPs showing association in the Irish phase were genotyped in a replication sample of 281 Swedish sporadic ALS patients and 286 Swedish controls. Seven markers showed association in the Irish. The one modest replication signal observed in the Swedish replication sample, at rs3801158 in the gene inhibin beta A, was for the opposite allele vs. the Irish cohort. We failed to detect association of common variation across 24 candidate hypoxia-inducible angiogenic genes with SALS.

  14. Hypoxia-inducible factor-1α and semaphorin4D genes involved with tumor-associated macrophage-induced metastatic behavior and clinical significance in colon cancer.

    Science.gov (United States)

    Mu, Linjun; Wang, Jinshen; Chen, Yuezhi; Li, Leping; Guo, Xiaobo; Zheng, Sheng; Jing, Changqing

    2014-01-01

    Hypoxia promotes tumor angiogenesis and hypoxia-inducible factor-1 alpha (HIF-1α) plays a pivotal role in this process. Recently identified pro-angiogenic factor, semaphorin4D (Sema4D) also promotes angiogenesis and enhances invasive proliferation in some tumors. Furthermore, tumor-associated macrophages (TAMs) can increase the expression of HIF-1α and Sema4D in cancer cells and thus influence tumor growth and progression. The purpose of this study was to evaluate the effect of TAMs on the expression of Sema4D and HIF-1α and the impact of biologic behavior in colon cancer cells. Immunohistochemistry was used to analyze HIF-1α and Sema4D expression in 86 curatively resected colon cancer samples and 52 normal colon tissues samples. The relationship between their expression and clinicopathological factors was analyzed. Furthermore, macrophage-tumor cell interactions, such as metastasis, angiogenesis, were also studied using in vitro co-culture systems. Statistical analysis was performed using SPSS 17.0 software (SPSS Inc., USA). Differences between two groups were analyzed with Student's t test. HIF-1α (58%) and Sema4D (60%) were expressed at a significantly higher level in tumors than in normal tissues (P TNM stages (P 0.05). Sema4D expression was correlated with that of HIF-1α (r = 0.567, P colon cancer cells and subsequently increased their migration and invasion. HIF-1α and Sema4D expression are closely related to lymphatic metastasis, specific histological types and TNM stages in colon cancer. Furthermore, TAMs promote migration and invasion of colon cancer cells and endothelial tube formation, possibly through up-regulation of HIF-1α and Sema4D.

  15. Hypobaric intermittent hypoxia attenuates hypoxia-induced depressor response.

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    Fang Cui

    Full Text Available BACKGROUND: Hypobaric intermittent hypoxia (HIH produces many favorable effects in the cardiovascular system such as anti-hypertensive effect. In this study, we showed that HIH significantly attenuated a depressor response induced by acute hypoxia. METHODOLOGY/PRINCIPAL FINDINGS: Sprague-Dawley rats received HIH in a hypobaric chamber simulating an altitude of 5000 m. The artery blood pressure (ABP, heart rate (HR and renal sympathetic nerve activity (RSNA were recorded in anesthetized control rats and rats received HIH. The baseline ABP, HR and RSNA were not different between HIH and control rats. Acute hypoxia-induced decrease in ABP was significantly attenuated in HIH rat compared with control rats. However, acute hypoxia-induced increases in HR and RSNA were greater in HIH rat than in control rats. After removal of bilateral ascending depressor nerves, acute hypoxia-induced depressor and sympathoexcitatory responses were comparable in control and HIH rats. Furthermore, acute hypoxia-induced depressor and sympathoexcitatory responses did not differ between control and HIH groups after blocking ATP-dependent K(+ channels by glibenclamide. The baroreflex function evaluated by intravenous injection of phenylephrine and sodium nitroprusside was markedly augmented in HIH rats compared with control rats. The pressor and sympathoexcitatory responses evoked by intravenous injection of cyanide potassium were also significantly greater in HIH rats than in control rats. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that HIH suppresses acute hypoxia-induced depressor response through enhancement of baroreflex and chemoreflex function, which involves activation of ATP-dependent K(+ channels. This study provides new information and underlying mechanism on the beneficiary effect of HIH on maintaining cardiovascular homeostasis.

  16. Factors regulated by interferon gamma and hypoxia-inducible factor 1A contribute to responses that protect mice from Coccidioides immitis infection

    Directory of Open Access Journals (Sweden)

    Woelk Christopher H

    2012-09-01

    Full Text Available Abstract Background Coccidioidomycosis results from airborne infections caused by either Coccidioides immitis or C. posadasii. Both are pathogenic fungi that live in desert soil in the New World and can infect normal hosts, but most infections are self-limited. Disseminated infections occur in approximately 5% of cases and may prove fatal. Mouse models of the disease have identified strains that are resistant (e.g. DBA/2 or susceptible (e.g. C57BL/6 to these pathogens. However, the genetic and immunological basis for this difference has not been fully characterized. Results Microarray technology was used to identify genes that were differentially expressed in lung tissue between resistant DBA/2 and sensitive C57BL/6 mice after infection with C. immitis. Differentially expressed genes were mapped onto biological pathways, gene ontologies, and protein interaction networks, which revealed that innate immune responses mediated by Type II interferon (i.e., IFNG and the signal transducer and activator of transcription 1 (STAT1 contribute to the resistant phenotype. In addition, upregulation of hypoxia inducible factor 1A (HIF1A, possibly as part of a larger inflammatory response mediated by tumor necrosis factor alpha (TNFA, may also contribute to resistance. Microarray gene expression was confirmed by real-time quantitative PCR for a subset of 12 genes, which revealed that IFNG HIF1A and TNFA, among others, were significantly differentially expressed between the two strains at day 14 post-infection. Conclusion These results confirm the finding that DBA/2 mice express more Type II interferon and interferon stimulated genes than genetically susceptible strains and suggest that differential expression of HIF1A may also play a role in protection.

  17. Analysis of Expression of Vascular Endothelial Growth Factor A and Hypoxia Inducible Factor-1alpha in Patients Operated on Stage I Non-Small-Cell Lung Cancer

    Science.gov (United States)

    Honguero Martínez, Antonio Francisco; Arnau Obrer, Antonio; Figueroa Almánzar, Santiago; León Atance, Pablo; Guijarro Jorge, Ricardo

    2014-01-01

    Objectives. Recent studies show that expression of hypoxia inducible factor-1alpha (HIF-1α) favours expression of vascular endothelial growth factor A (VEGF-A), and these biomarkers are linked to cellular proliferation, angiogenesis, and metastasis in different cancers. We analyze expression of HIF-1α and VEGF-A to clinicopathologic features and survival of patients operated on stage I non-small-cell lung cancer. Methodology. Prospective study of 52 patients operated on with stage I. Expression of VEGF-A and HIF-1α was performed through real-time quantitative polymerase chain reaction (qRT-PCR). Results. Mean age was 64.7 and 86.5% of patients were male. Stage IA represented 23.1% and stage IB 76.9%. Histology classification was 42.3% adenocarcinoma, 34.6% squamous cell carcinoma, and 23.1% others. Median survival was 81.0 months and 5-year survival 67.2%. There was correlation between HIF-1α and VEGF-A (P = 0.016). Patients with overexpression of HIF-1α had a tendency to better survival with marginal statistical significance (P = 0.062). Patients with overexpression of VEGF-A had worse survival, but not statistically significant (P = 0.133). Conclusion. The present study revealed that VEGF-A showed correlation with HIF-1α. HIF-1α had a tendency to protective effect with a P value close to statistical significance. VEGF-A showed a contrary effect but without statistical significance. PMID:26316946

  18. Analysis of Expression of Vascular Endothelial Growth Factor A and Hypoxia Inducible Factor-1alpha in Patients Operated on Stage I Non-Small-Cell Lung Cancer

    Directory of Open Access Journals (Sweden)

    Antonio Francisco Honguero Martínez

    2014-01-01

    Full Text Available Objectives. Recent studies show that expression of hypoxia inducible factor-1alpha (HIF-1α favours expression of vascular endothelial growth factor A (VEGF-A, and these biomarkers are linked to cellular proliferation, angiogenesis, and metastasis in different cancers. We analyze expression of HIF-1α and VEGF-A to clinicopathologic features and survival of patients operated on stage I non-small-cell lung cancer. Methodology. Prospective study of 52 patients operated on with stage I. Expression of VEGF-A and HIF-1α was performed through real-time quantitative polymerase chain reaction (qRT-PCR. Results. Mean age was 64.7 and 86.5% of patients were male. Stage IA represented 23.1% and stage IB 76.9%. Histology classification was 42.3% adenocarcinoma, 34.6% squamous cell carcinoma, and 23.1% others. Median survival was 81.0 months and 5-year survival 67.2%. There was correlation between HIF-1α and VEGF-A (P=0.016. Patients with overexpression of HIF-1α had a tendency to better survival with marginal statistical significance (P=0.062. Patients with overexpression of VEGF-A had worse survival, but not statistically significant (P=0.133. Conclusion. The present study revealed that VEGF-A showed correlation with HIF-1α. HIF-1α had a tendency to protective effect with a P value close to statistical significance. VEGF-A showed a contrary effect but without statistical significance.

  19. FoxO4 interacts with the sterol regulatory factor SREBP2 and the hypoxia inducible factor HIF2α at the CYP51 promoter.

    Science.gov (United States)

    Zhu, Jun; Jiang, Xiangning; Chehab, Farid F

    2014-03-01

    The late steps of cholesterol biosynthesis are oxygen demanding, requiring eleven oxygen molecules per synthesized cholesterol molecule. A key enzymatic reaction, which occurs at the top of the Bloch and Kandutsch-Russell pathways, is the demethylation of lanosterol and dihydrolanosterol (DHL). This reaction is catalyzed by lanosterol 14α demethylase (CYP51) and requires three oxygen molecules. Thus, it is the first step in the distal pathway to be susceptible to oxygen deprivation. Having previously identified that the forkhead transcription factor 4 (FoxO4) represses CYP51 expression, we aimed to characterize its role at the CYP51 promoter. Hypoxia-treated 3T3L1 cells showed decreased cholesterol biosynthesis, accumulation of lanosterol/DHL, and stimulation of FoxO4 expression and its cytoplasmic translocation to the nucleus. Transfection assays with a CYP51 promoter reporter gene revealed that FoxO4 and sterol regulatory element binding protein (SREBP)2 exert a stimulatory effect, whereas FoxO4 and the hypoxia inducible factor (HIF)2α repress CYP51 promoter activity. Electromobility shift, chromatin immunoprecipitation, pull-down, and coimmunoprecipitation assays show that FoxO4 interacts with SREBP2 and HIF2α to modulate CYP51 promoter activity. We also show an inverse correlation between FoxO4 and CYP51 in adipose tissue of ob/ob mice and mouse fetal cortical neurons exposed to hypoxia. Overall, these studies demonstrate a role for FoxO4 in the regulation of CYP51 expression.

  20. Activation of the hypoxia-inducible factor pathway induced by prolyl hydroxylase domain 2 deficiency enhances the effect of running training in mice.

    Science.gov (United States)

    Nunomiya, A; Shin, J; Kitajima, Y; Dan, T; Miyata, T; Nagatomi, R

    2017-05-01

    Hypoxic response mediated by hypoxia-inducible factor (HIF) seems to contribute to the benefit of endurance training. To verify the direct contribution of HIF activation to running training without exposure to atmospheric hypoxia, we used prolyl hydroxylase domain 2 (PHD2) conditional knockout mice (cKO), which exhibit HIF activation independent of oxygen concentration, and we examined their maximal exercise capacity before and after 4 weeks of treadmill exercise training. Phd2(f/f) mice (n = 26) and Phd2 cKO mice (n = 24) were randomly divided into two groups, trained and untrained, and were subjected to maximal running test before and after a 4-week treadmill-training regimen. Prolyl hydroxylase domain 2 deficiency resulted in HIF-α protein accumulation. Phd2 cKO mice exhibited marked increases in haematocrit values and haemoglobin concentrations, as well as an increase in the capillary number in the skeletal muscle. The 4-week training elicited an increase in the capillary-to-fibre (C/F) ratio and succinyl dehydrogenase activity of the skeletal muscle. Importantly, trained Phd2 cKO mice showed a significantly greater improvement in running time than trained control mice (P training and the activation of the HIF pathway are important for maximizing the effect of running training. We conclude that the activation of the HIF pathway induced by PHD2 deficiency enhances the effect of running training. © 2016 The Authors. Acta Physiologica published by John Wiley & Sons Ltd on behalf of Scandinavian Physiological Society.

  1. Enhanced hypoxia-inducible factor (HIF)-1α stability induced by 5-hydroxymethyl-2-furfural (5-HMF) contributes to protection against hypoxia.

    Science.gov (United States)

    He, Yun-Ling; Li, Ming-Ming; Wu, Li-Ying; Zhao, Tong; Di, Yao; Huang, Xin; Ding, Xue-Feng; Wu, Kui-Wu; Fan, Ming; Zhu, Ling-Ling

    2014-01-01

    We first reported the role of 5-hydroxymethyl-2-furfural (5-HMF) against hypoxia. Here, we studied the mechanism by using oxygen-dependent degradation domain (ODD)-Luc mice, which are a useful model to probe the stabilization of hypoxia-inducible factor 1α (HIF-1α). Compared with three other compounds that have been reported to have a role in stabilizing HIF-1α, 5-HMF caused stronger bioluminescence, which is indicative of HIF-1α stability in the brain and kidney of ODD-Luc mice. We further demonstrated that the HIF-1α protein accumulated in response to 5-HMF in the brains and kidneys of these mice, as well as in PC12 cells. Additionally, 5-HMF promoted the nuclear translocation of HIF-1α and the transcriptional activity of HIF-1, which was evaluated by detecting vascular endothelial growth factor (VEGF ) mRNA expression. These results suggest that 5-HMF stabilized HIF-1α and increased its activity. Considering the role of proline hydroxylases (PHDs) in negatively regulating HIF-1α stability, we explored whether 5-HMF interacts with the substrates and cofactors of PHDs, such as 2-oxoglutarate (2-OG), Fe(2+) and vitamin C (VC), which affects the activity of PHDs. The result revealed that 5-HMF did not interact with Fe(2+) or 2-OG but interacted with VC. This interaction was confirmed by subsequent experiments, in which 5-HMF entered into cells and reduced the VC content. The enhanced stability of HIF-1α by 5-HMF was reversed by VC supplementation, and the improved survival of mice caused by 5-HMF under hypoxia was abrogated by VC supplementation. Thus, we demonstrated for the first time that 5-HMF increases HIF-1α stability by reducing the VC content, which mediates the protection against hypoxia.

  2. The hypoxia-inducible factor-responsive proteins semaphorin 4D and vascular endothelial growth factor promote tumor growth and angiogenesis in oral squamous cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Hua; Yang, Ying-Hua [Department of Oncology and Diagnostic Sciences, University of Maryland Dental School, 650W. Baltimore Street, 7-North, Baltimore, MD 21201 (United States); Binmadi, Nada O. [Department of Oncology and Diagnostic Sciences, University of Maryland Dental School, 650W. Baltimore Street, 7-North, Baltimore, MD 21201 (United States); Department of Oral Basic and Clinical Sciences, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Proia, Patrizia [Department of Oncology and Diagnostic Sciences, University of Maryland Dental School, 650W. Baltimore Street, 7-North, Baltimore, MD 21201 (United States); Department of Sports Science (DISMOT), University of Palermo, Via Eleonora Duse 2 90146, Palermo (Italy); Basile, John R., E-mail: jbasile@umaryland.edu [Department of Oncology and Diagnostic Sciences, University of Maryland Dental School, 650W. Baltimore Street, 7-North, Baltimore, MD 21201 (United States); Greenebaum Cancer Center, 22S. Greene Street, Baltimore, MD 21201 (United States)

    2012-08-15

    Growth and metastasis of solid tumors requires induction of angiogenesis to ensure the delivery of oxygen, nutrients and growth factors to rapidly dividing transformed cells. Through either mutations, hypoxia generated by cytoreductive therapies, or when a malignancy outgrows its blood supply, tumor cells undergo a change from an avascular to a neovascular phenotype, a transition mediated by the hypoxia-inducible factor (HIF) family of transcriptional regulators. Vascular endothelial growth factor (VEGF) is one example of a gene whose transcription is stimulated by HIF. VEGF plays a crucial role in promoting tumor growth and survival by stimulating new blood vessel growth in response to such stresses as chemotherapy or radiotherapy-induced hypoxia, and it therefore has become a tempting target for neutralizing antibodies in the treatment of advanced neoplasms. Emerging evidence has shown that the semaphorins, proteins originally associated with control of axonal growth and immunity, are regulated by changes in oxygen tension as well and may play a role in tumor-induced angiogenesis. Through the use of RNA interference, in vitro and in vivo angiogenesis assays and tumor xenograft experiments, we demonstrate that expression of semaphorin 4D (SEMA4D), which is under the control of the HIF-family of transcription factors, cooperates with VEGF to promote tumor growth and vascularity in oral squamous cell carcinoma (OSCC). We use blocking antibodies to show that targeting SEMA4D function along with VEGF could represent a novel anti-angiogenic therapeutic strategy for the treatment of OSCC and other solid tumors. -- Highlights: Black-Right-Pointing-Pointer Similar to VEGF, SEMA4D promotes angiogenesis in vitro and in vivo. Black-Right-Pointing-Pointer Both VEGF and SEMA4D are produced by OSCC cells in a HIF-dependent manner. Black-Right-Pointing-Pointer These factors combine to elicit a robust pro-angiogenic phenotype in OSCC. Black-Right-Pointing-Pointer Anti-SEMA4D

  3. Regulatory effect of hypoxia-inducible factor-1α on hCG-stimulated endothelin-2 expression in granulosa cells from the PMSG-treated rat ovary.

    Science.gov (United States)

    Zhang, Jisen; Zhang, Zhenghong; Wu, Yanqing; Chen, Liyun; Luo, Qianping; Chen, Jiajie; Huang, Xiaohong; Cheng, Yong; Wang, Zhengchao

    2012-01-01

    Endothelin (ET)-2 plays a crucial role in ovarian ovulation in mammals. The present study was designed to test the hypothesis that hypoxia-inducible factor (HIF)-1α-mediated transcriptional activation contributes to the increased expression of ET-2 gene in response to hCG in rat ovarian granulosa cells (GCs) during gonadotropin-induced superovulation. By real-time RT-PCR analysis, ET-2 mRNA expression was found to significantly increase in cultured ovarian GCs after treatment with hCG, or even N-carbobenzoxyl-L-leucinyl-L-leucinyl-L-norvalinal (MG-132), while this increased ET-2 mRNA expression could also be blocked by ferrous ammonium sulfate (FAS) under human chorionic gonadotropin (hCG) treatment. Further analysis also found that these changes of ET-2 mRNA were consistent with HIF-1α expression or HIF-1 activity, and HIF-1α inhibitor echinomycin inhibited ovulation in rats. Taken together, these results indicate that ET-2 is transcriptionally activated by hCG through HIF-1α-mediated mechanism in GCs. This HIF-1α-induced transcriptional activation may be one of the important mechanisms mediating the increase of ET-2 expression in GCs during the gonadotropin-induced mammalian ovulatory process in vivo.

  4. Ultraviolet-B induced expression of hypoxia-inducible factor 1α,transferrin receptor through EGFR/PI3K/AKT/DEC1 pathway

    Institute of Scientific and Technical Information of China (English)

    LI Yanhua; BI Zhigang

    2007-01-01

    The aim of this research was to explore the effects and signaling pathway of ultraviolet-B (UVB) irradiation on the expression of hypoxia-inducible factor 1α (HIF-1α) and transferrin receptor (TfR).HIF-1α protein was measured by Western blot method.Expressions of epidermal growth factor receptor (EGFR),phosphor-EGF-R and TfR after UVB irradiation were determined with flow cytometry.After UVB irradiation,mRNA levels of HIF-1α and TfR were detected by real time-PCR.Results showed that compared with control groups,UVB was able to induce HIF1α and TfR protein expression in a dose- and time-dependent manner in HaCat cells (P < 0.05).TfR mRNA was expressed in a dose-dependent manner and reached a peak at the 8th hour in HaCat cells (P<0.05) whereas HIF-1α mRNA expression was not affected by UVB treatment (P>0.05).The EGFR/PI3K/AKT signaling pathway was required for the induction of HIF-lcx and TfR expression induced by UVB.UVB induced activation of EGFR in HaCat cells and EGFR regulated expression of TfR and HIF-1α.EGFR (-/-) MEF did not increase the HIF 1 expression following UVB irradiation (P>0.05).In contrast,EGFR (+/+) MEF strongly enhanced HIF 1α expression after UVB irradiation (P < 0.05).PD153035,a selective inhibitor of EGFR tyrosine kinase,inhibited the TfR protein expression in UVB-treated cells in a dose-dependent manner (P<0.05).PI3K inhibitors,LY294002 and wortmannin,inhibited HIF-1α and TfR expressions induced by UVB (P < 0.05).The DEC1 (-/-) Ha-Cat cells did not increase their TfR and HIF-1α expressions following UVB irradiation (P>0.05).In contrast,DEC1 (+/+) HaCat cells strongly enhanced TfR and HIF-1α protein expression after UVB irradiation (P<0.05).We conclude that UVB induces TfR and HIF-1α expressions via EGFR/PI3K/AKT/DEC1 signaling pathway.

  5. Regulations and Posttranslational Modifications of Hypoxia Inducible Factor-1%缺氧诱导因子-1的调控及其转录后修饰

    Institute of Scientific and Technical Information of China (English)

    石红联; 常彦忠

    2012-01-01

    缺氧诱导因子-1(hypoxia inducible factor-1,HIF-1)是一种异源二聚体转录因子,由结构表达型β亚基和氧调节型α亚基组成.在低氧环境下,HIF-1调控一系列促进细胞成活的基因,这些基因涉及血管生成、铁代谢、葡萄糖代谢和细胞增殖与存活.α亚基主要受到诸如乙酰化、羟基化、磷酸化和相扑化等转录后修饰,这些修饰可以稳定或激活HIF-1的活性.除氧环境外,胞内氧化还原稳态、铁代谢、线粒体代谢物和生长因子还可通过影响转录后修饰进而调节HIF-1的活性.此外,近来的研究表明HIF-1在病原学方面也发挥重要作用.在中风和神经退行性疾病这样的脑紊乱疾病中提供潜在神经保护作用.本文总结了HIF-1研究的最新进展,谨以此文献给忻文娟教授80周年诞辰.%Hypoxia inducible factor-1 (HIF-1),a transcriptional factor,is a heterodimer consisting of a constitutively expressed β subunit and an oxygen-regulated α subunit.It regulates a series of genes that participate in angiogenesis,iron metabolism,glucose metabolism,and cell proliferation/survival,which promote cell survival under hypoxic conditions.The α subunit is subjected to posttransletional modifications,such as acetylation,hydroxylation,phosphorylation,and sumoylation.These modifications determine the stabilization and activity of HIF-1.Besides oxygen,cellular redox homeostasis,iron metabolism,mitochondrial metabolites,and growth factors affect the post-translational modification and thus regulate HIF-1 activity.Furthermore,recent studies have demonstrated that HIF-1 plays an important role in the pathogeneses of and provides potential neuroprotection in many brain disorders such as stroke and neurodegenerative diseases.This article summarizes recent progress on these issues and is dedicated to Professor Wenjuan Xin on the occasion of her 80th birthday.

  6. KAJIAN PERAN MANGANESE-CONTAINING SUPER OXIDE DISMUTASE (MNSOD DALAM REGULASI EKSPRESI HYPOXIA INDUCIBLE FACTOR-1α (HIF-1α PADA KEADAAN HIPOKSIA

    Directory of Open Access Journals (Sweden)

    Masagus Zainuri

    2014-02-01

    Full Text Available AbstrakKekurangan suplai oksigen pada jaringan disebut hipoksia. Sel tumor sering mengalami hipoksia dan menjadi tidak responsif terhadap terapi. Keadaan hipoksia pada jaringan tumor perlu ditanggulangi agar keberhasilan terapi tumor dapat  ditingkatkan.  Pada keadaan hipoksia,  factor  Hypoxia Inducible Factor-1α  (HIF-1α berperan  penting  dalam pengendalian respon selular. Ekspresi gen HIF-1α sangat dipengaruhi oleh status redoks sel. Enzim MnSOD merupakan enzim antioksidan endogen yang berperan sebagai scavenger O2.-yang menghasilkan H2O2 dan O2 , sehingga aktivitas MnSOD akan mempengaruhi status redoks dari sel. Melalui O2.-dan H2O2, MnSOD memiliki peran biphasic terhadap regulasi ekspresi gen HIF-1α, sehingga dapat menekan dampak hipoksia pada jaringan. Sampai saat ini MnSOD belum dimanfaatkan  sebagai  terapi  pendukung  pada  terapi tumor  dan  perlu  dilakukan  banyak  eksperimen  untuk mengeksplorasi potensi MnSOD sebagai terapi adjuvant alternative untuk terapi tumor.Kata Kunci : MnSOD, HIF-1α, Superoksida (O2.-, Hidrogen Peroksida (H2O2AbstractInsufficient oxygen supply in tissue is named hypoxia. Tumor cells frequentlyexperience tissue hypoxia, therefore it becomes irresponsive to the main therapy. Hypoxia of tumor tissue needs to be solved to improve the tumor therapy succeed. In hypoxia, Hypoxia Inducible Factor-1α (HIF-1α plays an essential role in controlling the cellular responses. HIF-1α  gene  expression  is  influenced  by  the  redox stateof the cells. MnSOD enzyme is an endogenous antioxidant enzyme that acting as an O2.-scavenger that producing H2O2 and O2, so that MnSOD activity would affect the redox state of the cells. ViaO2.-and H2O2, MnSOD has a biphasic role for gene expression of HIF-1α regulation and reducing the tissue hypoxia effect. Recently, MnSOD is not an adjuvant therapy for tumor treatment yet, and some experiments are needed to explore MnSOD potential as an alternative

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-03-29

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

  8. Hypoxia inducible factor-1α inhibition produced anti-allodynia effect and suppressed inflammatory cytokine production in early stage of mouse complex regional pain syndrome model.

    Science.gov (United States)

    Hsiao, Hung-Tsung; Lin, Ya-Chi; Wang, Jeffrey Chi-Fei; Tsai, Yu-Chuan; Liu, Yen-Chin

    2016-03-01

    Complex regional pain syndrome (CRPS) is related to microcirculation impairment associated with tissue hypoxia and peripheral cytokine overproduction in the affected limb. Previous studies suggest that the pathogenesis involves hypoxia inducible factor-1α (HIF-1α) and exaggerated regional inflammatory response. 1-methylpropyl 2-imidazolyl disulfide (PX-12) acts as the thioredoxin-1 (Trx-1) inhibitor and decreases the level of HIF-1α, and can rapidly be metabolized for Trx-1 redox inactivation. This study hypothesized that PX-12 can decrease the cytokine production for nociceptive sensitization in the hypoxia-induced pain model. CD1 mice weighing around 30 g were used. The animal CRPS model was developed via the chronic post-ischaemic pain (CPIP) model. The model was induced by using O-rings on the ankles of the mice hind limbs to produce 3-h ischaemia-reperfusion injury on the paw. PX-12 (25 mg/kg, 5 mg/kg) was given through tail vein injection immediately after ischaemia. Animal behaviour was tested using the von Frey method for 7 days. Local paw skin tissue was harvest from three groups (control, 5 mg/kg, 25 mg/kg) 2 h after injection of PX-12. The protein expression of interleukin-1β (IL-1β) and HIF-1α was analysed with the Western blotting method. Mice significantly present an anti-allodynia effect in a dose-related manner after the PX-12 administration. Furthermore, PX-12 not only decreased the expression of HIF-1α but also decreased the expression of IL-1β over the injured palm. This study, therefore, shows the first evidence of the anti-allodynia effect of PX-12 in a CPIP animal model for pain behaviour. The study concluded that inhibition of HIF-1α may produce an analgesic effect and the associated suppression of inflammatory cytokine IL-1β in a CPIP model. © 2016 John Wiley & Sons Australia, Ltd.

  9. Transcriptional activation of hypoxia-inducible factor-1 (HIF-1) in myeloid cells promotes angiogenesis through VEGF and S100A8.

    Science.gov (United States)

    Ahn, G-One; Seita, Jun; Hong, Beom-Ju; Kim, Young-Eun; Bok, Seoyeon; Lee, Chan-Ju; Kim, Kwang Soon; Lee, Jerry C; Leeper, Nicholas J; Cooke, John P; Kim, Hak Jae; Kim, Il Han; Weissman, Irving L; Brown, J Martin

    2014-02-18

    Emerging evidence indicates that myeloid cells are essential for promoting new blood vessel formation by secreting various angiogenic factors. Given that hypoxia-inducible factor (HIF) is a critical regulator for angiogenesis, we questioned whether HIF in myeloid cells also plays a role in promoting angiogenesis. To address this question, we generated a unique strain of myeloid-specific knockout mice targeting HIF pathways using human S100A8 as a myeloid-specific promoter. We observed that mutant mice where HIF-1 is transcriptionally activated in myeloid cells (by deletion of the von Hippel-Lindau gene) resulted in erythema, enhanced neovascularization in matrigel plugs, and increased production of vascular endothelial growth factor (VEGF) in the bone marrow, all of which were completely abrogated by either genetic or pharmacological inactivation of HIF-1. We further found that monocytes were the major effector producing VEGF and S100A8 proteins driving neovascularization in matrigel. Moreover, by using a mouse model of hindlimb ischemia we observed significantly improved blood flow in mice intramuscularly injected with HIF-1-activated monocytes. This study therefore demonstrates that HIF-1 activation in myeloid cells promotes angiogenesis through VEGF and S100A8 and that this may become an attractive therapeutic strategy to treat diseases with vascular defects.

  10. Hypoxia-Mediated Down-Regulation of Bid and Bax in Tumors Occurs via Hypoxia-Inducible Factor 1-Dependent and -Independent Mechanisms and Contributes to Drug Resistance

    Science.gov (United States)

    Erler, Janine T.; Cawthorne, Christopher J.; Williams, Kaye J.; Koritzinsky, Marianne; Wouters, Bradley G.; Wilson, Clare; Miller, Crispin; Demonacos, Costas; Stratford, Ian J.; Dive, Caroline

    2004-01-01

    Solid tumors with disorganized, insufficient blood supply contain hypoxic cells that are resistant to radiotherapy and chemotherapy. Drug resistance, an obstacle to curative treatment of solid tumors, can occur via suppression of apoptosis, a process controlled by pro- and antiapoptotic members of the Bcl-2 protein family. Oxygen deprivation of human colon cancer cells in vitro provoked decreased mRNA and protein levels of proapoptotic Bid and Bad. Hypoxia-inducible factor 1 (HIF-1) was dispensable for the down-regulation of Bad but required for that of Bid, consistent with the binding of HIF-1α to a hypoxia-responsive element (positions −8484 to −8475) in the bid promoter. Oxygen deprivation resulted in proteosome-independent decreased expression of Bax in vitro, consistent with a reduction in global translation efficiency. The physiological relevance of Bid and Bax down-regulation was confirmed in tumors in vivo. Oxygen deprivation resulted in decreased drug-induced apoptosis and clonogenic resistance to agents with different mechanisms of action. The contribution of Bid and/or Bax down-regulation to drug responsiveness was demonstrated by the relative resistance of normoxic cells that had no or reduced expression of Bid and/or Bax and by the finding that forced expression of Bid in hypoxic cells resulted in increased sensitivity to the topoisomerase II inhibitor etoposide. PMID:15024076

  11. Human AlkB homologue 5 is a nuclear 2-oxoglutarate dependent oxygenase and a direct target of hypoxia-inducible factor 1α (HIF-1α.

    Directory of Open Access Journals (Sweden)

    Armin Thalhammer

    Full Text Available Human 2-oxoglutarate oxygenases catalyse a range of biological oxidations including the demethylation of histone and nucleic acid substrates and the hydroxylation of proteins and small molecules. Some of these processes are centrally involved in regulation of cellular responses to hypoxia. The ALKBH proteins are a sub-family of 2OG oxygenases that are defined by homology to the Escherichia coli DNA-methylation repair enzyme AlkB. Here we report evidence that ALKBH5 is probably unique amongst the ALKBH genes in being a direct transcriptional target of hypoxia inducible factor-1 (HIF-1 and is induced by hypoxia in a range of cell types. We show that purified recombinant ALKBH5 is a bona fide 2OG oxygenase that catalyses the decarboxylation of 2OG but appears to have different prime substrate requirements from those so far defined for other ALKBH family members. Our findings define a new class of HIF-transcriptional target gene and suggest that ALKBH5 may have a role in the regulation of cellular responses to hypoxia.

  12. Hypoxia-inducible factor-1 (HIF-1) is involved in the regulation of hypoxia-stimulated expression of monocyte chemoattractant protein-1 (MCP-1/CCL2) and MCP-5 (Ccl12) in astrocytes

    OpenAIRE

    Mojsilovic-Petrovic Jelena; Callaghan Debbie; Cui Hong; Dean Clare; Stanimirovic Danica B; Zhang Wandong

    2007-01-01

    Abstract Background Neuroinflammation has been implicated in various brain pathologies characterized by hypoxia and ischemia. Astroglia play an important role in the initiation and propagation of hypoxia/ischemia-induced inflammation by secreting inflammatory chemokines that attract neutrophils and monocytes into the brain. However, triggers of chemokine up-regulation by hypoxia/ischemia in these cells are poorly understood. Hypoxia-inducible factor-1 (HIF-1) is a dimeric transcriptional fact...

  13. Combined over-expression of the hypoxia-inducible factor 2α gene and its long non-coding RNA predicts unfavorable prognosis of patients with osteosarcoma.

    Science.gov (United States)

    Li, Wei; He, Xijing; Xue, Rongliang; Zhang, Ying; Zhang, Xiaoqin; Lu, Jianrui; Zhang, Zhenni; Xue, Li

    2016-10-01

    LncRNA hypoxia-inducible factor-2α (HIF-2α) promoter upstream transcript (HIF2PUT) functions as a novel regulatory factor of osteosarcoma stem cells partly by controlling HIF-2α expression. The aim of this study was to investigate the clinical significance of HIF-2α and HIF2PUT in human osteosarcoma. Quantitative real-time PCR was performed to detect the expression levels of HIF-2α mRNA and HIF2PUT in 82 surgical specimens of primary osteosarcoma and matched non-cancerous bone tissues. Then, the associations of HIF-2α and/or HIF2PUT expression with various clinicopathological features of osteosarcoma patients were statistically analyzed. Moreover, their prognostic value was further evaluated. Compared with non-cancerous bone tissues, HIF-2α mRNA and HIF2PUT expression were both significantly upregulated in osteosarcoma tissues (all Posteosarcoma tissues were positively correlated with those of HIF2PUT (r=0.28, P=0.009). Additionally, osteosarcoma patients with HIF-2α mRNA and/or HIF2PUT over-expression more frequently had large tumor size (all Posteosarcoma patients with HIF-2α mRNA and/or HIF2PUT over-expression had a significantly shorter overall and disease-free survival (all Posteosarcomas with aggressive potency. The over-expression of the two molecules, alone or combined, may predict poor prognosis in osteosarcoma patients. Copyright © 2016. Published by Elsevier GmbH.

  14. The Role of Hypoxia-Inducible Factor-1α, Glucose Transporter-1, (GLUT-1 and Carbon Anhydrase IX in Endometrial Cancer Patients

    Directory of Open Access Journals (Sweden)

    Pawel Sadlecki

    2014-01-01

    Full Text Available Hypoxia-inducible factor-1α (HIF-1α, glucose transporter-1 (GLUT-1, and carbon anhydrase IX (CAIX are important molecules that allow adaptation to hypoxic environments. The aim of our study was to investigate the correlation between HIF-1α, GLUT-1, and CAIX protein level with the clinicopathological features of endometrial cancer patients. Materials and Methods. 92 endometrial cancer patients, aged 37–84, were enrolled to our study. In all patients clinical stage, histologic grade, myometrial invasion, lymph node, and distant metastases were determined. Moreover, the survival time was assessed. Immunohistochemical analyses were performed on archive formalin fixed paraffin embedded tissue sections. Results. High significant differences (P=0.0115 were reported between HIF-1α expression and the histologic subtype of cancer. Higher HIF-1α expression was associated with the higher risk of recurrence (P=0.0434. The results of GLUT-1 and CAIX expression did not reveal any significant differences between the proteins expression in the primary tumor and the clinicopathological features. Conclusion. The important role of HIF-1α in the group of patients with the high risk of recurrence and the negative histologic subtype of the tumor suggest that the expression of this factor might be useful in the panel of accessory pathomorphological tests and could be helpful in establishing more accurate prognosis in endometrial cancer patients.

  15. A new anti-angiogenic small molecule, G0811, inhibits angiogenesis via targeting hypoxia inducible factor (HIF)-1α signal transduction

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Hyun; Jung, Hye Jin; Kwon, Ho Jeong, E-mail: kwonhj@yonsei.ac.kr

    2013-11-15

    Highlights: •G0811 suppresses HIF-1α expression without cell toxicity. •G0811 exhibits anti-angiogenic activity both in vitro and in vivo. •G0811 provides a new molecular scaffold for the development of therapeutics targeting angiogenesis. -- Abstract: Regulation of hypoxia inducible factor (HIF)-1α stabilization, which in turn contributes to adaptation of tumor cells to hypoxia has been highlighted as a promising therapeutic target in angiogenesis-related diseases. We have identified a new small molecule, G0811, as a potent angiogenesis inhibitor that targets HIF-1α signal transduction. G0811 suppressed HIF-1α stability in cancer cells and inhibited in vitro and in vivo angiogenesis, as validated by tube formation, chemoinvasion, and chorioallantoic membrane (CAM) assays. In addition, G0811 effectively decreased the expression of vascular endothelial growth factor (VEGF), which is one of target genes of HIF-1α. However, G0811 did not exhibit anti-proliferative activities or toxicity in human umbilical vein endothelial cells (HUVECs) at effective doses. These results demonstrate that G0811 could be a new angiogenesis inhibitor that acts by targeting HIF-1α signal transduction pathway.

  16. Hyperlipidemia does not prevent the cardioprotection by postconditioning against myocardial ischemia/reperfusion injury and the involvement of hypoxia inducible factor-1α upregulation

    Institute of Scientific and Technical Information of China (English)

    Huanxin Zhao; Yehong Wang; Ye Wu; Xiaoyu Li; Guangzhao Yang; Xiurui Ma; gongrui Zhao; Huirong Liu

    2009-01-01

    Hyperlipidemia is regarded as an independent risk factor in the development of ischemic heart disease, and it can increase the myocardial susceptibility to ischemia/reperfusion (I/R) injury, lschemic postcondi-tioning (Postcon) has been demonstrated to attenuate the myocardial injury induced by I/R in normal con-ditions. But the effect of ischemic Postcon on hyperlipi-demic animals is unknown. Hypoxia inducible factor-1 (HIF-1) has been demonstrated to play a central role in the cardioprotection by preconditioning, which is one of the protective strategies except for Postcon. The aim of this study was to determine whether Postcon could reduce myocardial injury in hyperlipidemic animals and to assess whether HIF-1 was involved in Postcon mechanisms. Male Wistar rats underwent the left anterior descending coronary occlusion for 30 min fol-lowed by 180 min of reperfusion with or without Postcon after fed with high fat diet or normal diet for 8 weeks. The detrimental indices induced by the I/R insult included infarct size, plasma creatine kinase activity and caspase-3 activity. Results showed that hyperlipidemia remarkably enhanced the myocardial injury induced by I/R, while Postcon significantly decreased the myocardial injury in both normolipi-demic and hyperlipidemic rats. Moreover, both hyperli-pidemia and IfR promoted the HIF-1α expression. Most importantly, we have for the first time demon-strated that Postcon further induced a significant increase in HIF-1α protein level not only in normolipi-demic but also in hyperlipidemic conditions. Thus, Postcon reduces the myocardial injury induced by I/R in normal and hyperlipidemic animals, and HIF-1αupregulation may involve in the Postcon-mediated car-dioprotective mechanisms.

  17. Assessment of hypoxia-inducible factor-1α mRNA expression in mantis shrimp as a biomarker of environmental hypoxia exposure.

    Science.gov (United States)

    Kodama, Keita; Rahman, Md Saydur; Horiguchi, Toshihiro; Thomas, Peter

    2012-04-23

    Efforts to assess the ecological impacts of the marked increase in coastal hypoxia worldwide have been hampered by a lack of biomarkers of hypoxia exposure in marine benthic organisms. Here, we show that hypoxia-inducible factor-1α (HIF-1α) transcript levels in the heart and cerebral ganglion of mantis shrimp (Oratosquilla oratoria) collected from hypoxic sites in Tokyo Bay are elevated several-fold over those in shrimp collected from normoxic sites. Upregulation of HIF-1α mRNA levels in the heart after exposure to sub-lethal hypoxia was confirmed in controlled laboratory experiments. HIF-1α transcript levels were increased at approximately threefold after 7 and 14 days of hypoxia exposure and declined to control levels within 24 h of restoration to normoxic conditions. The results provide the first evidence for upregulation of HIF-1α transcript levels in two hypoxia-sensitive organs, heart and cerebral ganglion, in a marine invertebrate exposed to environmental hypoxia. These results suggest that upregulation of HIF-1α transcript levels is an important component in adaptation of mantis shrimp to chronic hypoxia and is a potentially useful biomarker of environmental hypoxia exposure.

  18. Upregulation of NAD(P)H oxidase 1 in hypoxia activates hypoxia-inducible factor 1 via increase in reactive oxygen species.

    Science.gov (United States)

    Goyal, Parag; Weissmann, Norbert; Grimminger, Friedrich; Hegel, Cornelia; Bader, Lucius; Rose, Frank; Fink, Ludger; Ghofrani, Hossein A; Schermuly, Ralph T; Schmidt, Harald H H W; Seeger, Werner; Hänze, Jörg

    2004-05-15

    Hypoxia sensing and related signaling events, including activation of hypoxia-inducible factor 1 (HIF-1), represent key features in cell physiology and lung function. Using cultured A549 cells, we investigated the role of NAD(P)H oxidase 1 (Nox1), suggested to be a subunit of a low-output NAD(P)H oxidase complex, in hypoxia signaling. Nox1 expression was detected on both the mRNA and protein levels. Upregulation of Nox1 mRNA and protein occurred during hypoxia, accompanied by enhanced reactive oxygen species (ROS) generation. A549 cells, which were transfected with a Nox1 expression vector, revealed an increase in ROS generation accompanied by activation of HIF-1-dependent target gene expression (heme oxygenase 1 mRNA, hypoxia-responsive-element reporter gene activity). In A549 cells stably overexpressing Nox1, accumulation of HIF-1alpha in normoxia and an additional increase in hypoxia were noted. Interference with ROS metabolism by the flavoprotein inhibitor diphenylene iodonium (DPI) and catalase inhibited HIF-1 induction. This suggests that H2O2 links Nox1 and HIF-1 activation. We conclude that hypoxic upregulation of Nox1 and subsequently augmented ROS generation may activate HIF-1-dependent pathways.

  19. In Vivo Imaging of Hypoxia-Inducible Factor Regulation in a Subcutaneous and Orthotopic GL261 Glioma Tumor Model Using a Reporter Gene Assay

    Directory of Open Access Journals (Sweden)

    Sandra Bürgi

    2014-11-01

    Full Text Available Intratumoral hypoxia changes the metabolism of gliomas, leading to a more aggressive phenotype with increased resistance to radio- and chemotherapy. Hypoxia triggers a signaling cascade with hypoxia-inducible factor (HIF as a key regulator. We monitored activation of the HIF pathway longitudinally in murine glioma tumors. GL261 cells, stably transfected with a luciferase reporter driven under the control of a promoter comprising the HIF target gene motive hypoxia response element, were implanted either subcutaneously or orthotopically. In vivo experiments were carried out using bioluminescence imaging. Tumors were subsequently analyzed using immunofluorescence staining for hypoxia, endothelial cells, tumor perfusion, and glucose transporter expression. Transient upregulation of the HIF signaling was observed in both subcutaneous and orthotopic gliomas. Immunofluorescence staining confirmed hypoxic regions in subcutaneous and, to a lesser extent, intracranial tumors. Subcutaneous tumors showed substantial necrosis, which might contribute to the decreased bioluminescence output observed toward the end of the experiment. Orthotopic tumors were less hypoxic than subcutaneous ones and did not develop extensive necrotic areas. Although this may be the result of the overall smaller size of orthotopic tumors, it might also reflect differences in the local environment, such as the better intrinsic vascularization of brain tissue compared to the subcutaneous tissue compartment.

  20. Hypoxia-inducible factor-1-regulated protein expression and oligodendroglioma patient outcome: comparison with established biomarkers and preoperative UCSF low-grade scoring system.

    Science.gov (United States)

    Abraham, Shirley; Hu, Nan; Jensen, Randy

    2012-07-01

    Methods for predicting outcome for patients with oligodendrogliomas and anaplastic oligodendrogliomas (AOs) are limited. Hypoxia-inducible factor-1α (HIF-1α) controls many proteins involved in glycolysis and angiogenesis including VEGF, Glut-1, and CA-IX. We examined whether expression of HIF-1α and other hypoxia-regulated molecules (HRM) can predict overall (OS) and progression-free (PFS) survival. We correlated these data with more established biomarkers and a published preoperative scoring system. We prospectively collected tissue samples and followed outcomes of 50 patients with oligodendrogliomas and 32 with AOs. Tumor tissues were stained for measures of proliferative index, microvascular density, IDH-1 mutational status, and HRMs. We retrospectively analyzed preoperative imaging and clinical data based on the UCSF Scoring System (good prognostic indicators: Karnofsky Performance Scale (KPS) score > 80, age oligodendrogliomas. Both 1p19q codeletion and IDH-1 mutation predict outcome of patients with both oligodendroglioma and AO. The UCSF score is a strong predictor for oligodendrogliomas patient outcome and is strengthened by IDH-1 and 1p19q status. Glut-1 may be useful in predicting PFS in AOs. Proliferation index >5 for oligodendrogliomas and KPS ≤ 80 for AOs predict a worse prognosis. Immunohistochemical markers of HRMs show a significantly higher expression in anaplastic variants of oligodendrogliomas and may contribute to the prediction of survival in these patients.

  1. A novel thiol compound, N-acetylcysteine amide, attenuates allergic airway disease by regulating activation of NF-kappaB and hypoxia-inducible factor-1alpha.

    Science.gov (United States)

    Lee, Kyung Sun; Kim, So Ri; Park, Hee Sun; Park, Seoung Ju; Min, Kyung Hoon; Lee, Ka Young; Choe, Yeong Hun; Hong, Sang Hyun; Han, Hyo Jin; Lee, Young Rae; Kim, Jong Suk; Atlas, Daphne; Lee, Yong Chul

    2007-12-31

    Reactive oxygen species (ROS) play an important role in the pathogenesis of airway inflammation and hyperresponsiveness. Recent studies have demonstrated that antioxidants are able to reduce airway inflammation and hyperreactivity in animal models of allergic airway disease. A newly developed antioxidant, small molecular weight thiol compound, N-acetylcysteine amide (AD4) has been shown to increase cellular levels of glutathione and to attenuate oxidative stress related disorders such as Alzheimer's disease, Parkinson's disease, and multiple sclerosis. However, the effects of AD4 on allergic airway disease such as asthma are unknown. We used ovalbumin (OVA)-inhaled mice to evaluate the role of AD4 in allergic airway disease. In this study with OVA-inhaled mice, the increased ROS generation, the increased levels of Th2 cytokines and VEGF, the increased vascular permeability, the increased mucus production, and the increased airway resistance in the lungs were significantly reduced by the administration of AD4. We also found that the administration of AD4 decreased the increases of the NF-kappaB and hypoxia-inducible factor-1alpha (HIF-1alpha) levels in nuclear protein extracts of lung tissues after OVA inhalation. These results suggest that AD4 attenuates airway inflammation and hyperresponsiveness by regulating activation of NF-kappaB and HIF-1alpha as well as reducing ROS generation in allergic airway disease.

  2. Hypoxia-inducible factor-2 alpha promotes the proliferation of human placenta-derived mesenchymal stem cells through the MAPK/ERK signaling pathway

    Science.gov (United States)

    Zhu, Chengxing; Yu, Jiong; Pan, Qiaoling; Yang, Jinfeng; Hao, Guangshu; Wang, Yingjie; Li, Lanjuan; Cao, Hongcui

    2016-01-01

    Human placenta-derived mesenchymal stem cells (hPMSCs) reside in a physiologically low-oxygen microenvironment. Hypoxia influences a variety of stem cell cellular activities, frequently involving hypoxia-inducible factor-2 alpha (HIF-2α). This research showed that hPMSCs cultured in hypoxic conditions (5% O2) exhibited a more naïve morphology and had a higher proliferative capability and higher HIF-2α expression than hPMSCs cultured in normoxic conditions (21% O2). Similar to the hypoxic cultures, hPMSCs over-expressing HIF-2α showed higher proliferative potential and higher expression of CCND1 (CyclinD1), MYC (c-Myc), POU5F1 (Oct4) and the components of the MAPK/ERK pathway. In contrast, these genes were down-regulated in the HIF-2α-silenced hPMSCs. After adding the MAPK/ERK inhibitor PD0325901, cell growth and the expression of CCND1 and MYC were inhibited. Furthermore, the chromatin immunoprecipitation (ChIP) assay and electrophoretic mobility shift assay (EMSA) showed that HIF-2α bound to the MAPK3 (ERK1) promoter, indicative of its direct regulation of MAPK/ERK components at the transcriptional level during hPMSC expansion. Taken together, our results suggest that HIF-2α facilitated the preservation of hPMSC stemness and promoted their proliferation by regulating CCND1 and MYC through the MAPK/ERK signaling pathway. PMID:27765951

  3. A novel injectable BRET-based in vivo imaging probe for detecting the activity of hypoxia-inducible factor regulated by the ubiquitin-proteasome system

    Science.gov (United States)

    Kuchimaru, Takahiro; Suka, Tomoya; Hirota, Keisuke; Kadonosono, Tetsuya; Kizaka-Kondoh, Shinae

    2016-01-01

    The ubiquitin-proteasome system (UPS) is a selective protein degradation system that plays a critical role in many essential biological processes by regulating the existence of various cellular proteins. The target proteins of UPS are recognized and tagged with polyubiquitin chains by E3 ubiquitin ligases, which have high substrate-specific activities. Here we present a novel injectable imaging probe POL-N that can detect the UPS-regulated hypoxia-inducible factor (HIF) activity in vivo. Because the luciferase is fused to the E3 ligase-recognition domain of the HIF-1α, POL-N is intact only in the HIFα-overexpressing cells, that is, HIF-active cells, generating signals via an intramolecular bioluminescence resonance energy transfer (BRET) between luciferase and a near-infrared (NIR) fluorescent dye at the C-terminal end of the probe. Off-target signals of the NIR-BRET were so low that we could achieve highly sensitive and fast detection of intratumoral HIF-activity. Notably, we successfully detected hypoxic liver metastasis, which is extremely difficult to detect by injectable imaging probes due to strong off-target signals, as early as 1 h after systemic injection of POL-N. Our probe design can be widely adapted to UPS-target proteins and may contribute to the exploration of their roles in animal disease models. PMID:27698477

  4. [Effects of feixin decoction on the contents of hypoxia-inducible factor-1alpha and vascular endothelial growth factor in the rat model of hypoxic pulmonary hypertension].

    Science.gov (United States)

    He, Hong-Jun; Dai, Ai-Guo

    2012-05-01

    To explore the effects of Feixin Decoction (FXD) on the hypoxia-inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) in the rat model of hypoxic pulmonary hypertension (HPH), and to study its mechanisms for treating HPH. Forty healthy male SD rats were randomly divided into four groups, i. e., the normal control group, the HPH model group, the FXD group, and the Nifedipine group, 10 rats in each group. The HPH rat model was prepared using normal pressure intermittent hypoxia method. Except the normal control group, rats in the rest groups were fed in a self-made hypoxic plexiglass cabin, with the poor oxygen condition for 8 h daily for 14 successive days. Then the distilled water (at 30 mL/kg) was given by gastrogavage to rats in the normal control group and the HPH model group. FXD (at 28 g/kg) and Nifedipine (at 20 mg/kg) were given by gastrogavage to rats in the FXD group and the Nifedipine group respectively, once daily, for 14 successive days. Besides, hypoxia was continued for 14 days while medicating. The mean pulmonary artery pressure (mPAP) was detected on the second day after the last medication. The morphology of the pulmonary arteriole was detected. The ratio of pulmonary artery wall area and tube area (WA%) was determined. The protein and mRNA expressions of HIF-1alpha and VEGF were detected using immunohistochemistry and in situ hybridization technique. Compared with the normal control group, mPAP, WA%, and the protein and mRNA expressions of HIF-1alpha and VEGF significantly increased in the model group (P model group, mPAP, WA%, and the protein and mRNA expressions of HIF-1alpha and VEGF significantly decreased in the FXD group (P < 0.01, P < 0.05). FXD down-regulated the expression of VEGF through decreasing the expression of HIF-1alpha. One of its mechanisms for treating HPH might be partially due to reversing the remodeling of pulmonary vascular smooth muscle.

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

    Directory of Open Access Journals (Sweden)

    Koivunen P

    2016-03-01

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

  6. Truncated forms of BNIP3 act as dominant negatives inhibiting hypoxia-induced cell death

    Science.gov (United States)

    Bristow, Nicolle; Burton, Teralee R; Henson, Elizabeth S; Ong-Justiniano, Coleen; Brown, Michelle; Gibson, Spencer B

    2011-01-01

    BNIP3 (Bcl-2/adenovirus E1B Ninteen Kilodalton Interacting Protein) is a pro-cell death member of the Bcl-2 family of proteins. Its expression is induced by the transcription factor Hypoxia Inducible Factor-1 (HIF-1) under conditions of low oxygen (hypoxia) and is found over expressed in hypoxic regions of many tumors. When over expressed, BNIP3 induces cell death through induction of mitochondrial dysfunction that is dependant on the presence of BNIP3’s TM domain. Herein, we have determined that the SkOv3 ovarian cancer cell line expresses a truncated BNIP3 protein, which results in the elimination of the transmembrane domain. Truncation that eliminates all four domains of BNIP3 protein also inhibits hypoxia-induced cell death in SkOv3, HEK293, U251 and MCF-7 cells. Three different mutations in a BNIP3 expression vector that lead to a truncated BNIP3 protein, lacking TM domain only, or lacking CD, BH3, and TM domains resulted in inhibition of hypoxia-induced cell death when transfected into HEK293 cells. We found that truncated BNIP3 failed to associate with the mitochondria and the truncated BNIP3 lacking all four domains can bind to wild type BNIP3. Taken together, truncation of BNIP3 could be a novel mechanism for cancer cells to avoid hypoxia-induced cell death mediated by BNIP3 over expression. PMID:21138765

  7. Combinatorial MicroRNAs Suppress Hypoxia-Induced Cardiomyocytes Apoptosis

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    Yingqi Xu

    2015-09-01

    Full Text Available Background/Aims: Our previous in silico analysis revealed potential synergy in the activities of micro(miRNAs in myocardial infarction. The present study investigated whether miR-1 and -21 act synergistically to protect against cardiomyocytes apoptosis. Methods: Cell survival was analyzed with cell viability assay; apoptosis was detected by flow cytometry, terminal deoxynucleotidyl transferase dUTP nick end labeling, and the caspase-3 activity assay; and protein expression level was determined by western blotting. Results: MiR-1:miR-21 and several other miRNA pairs were evaluated for their potentially synergistic effects against myocardial hypoxia in neonatal rat ventricular cardiomyocytes. Lower combination indices suggested that miRNA pairs acted synergistically to inhibit apoptosis; miR-1 and -21 jointly blocked hypoxia-induced cardiomyocytes apoptosis. Moreover, combined application of miR-1 and -21 activated Akt and blocked hypoxia-induced upregulation of p53 in these cells. Conclusion: MiR-1 and -21 exert synergistic effects against hypoxia-induced cardiomyocytes apoptosis. These results provide a basis for the development of combined miRNA-based therapeutics to treat cardiovascular diseases.

  8. Induction of erythropoiesis by hypoxia-inducible factor prolyl hydroxylase inhibitors without promotion of tumor initiation, progression, or metastasis in a VEGF-sensitive model of spontaneous breast cancer

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    Seeley TW

    2017-03-01

    Full Text Available Todd W Seeley, Mark D Sternlicht, Stephen J Klaus, Thomas B Neff, David Y Liu Therapeutics R&D, FibroGen, Inc., San Francisco, CA, USA Abstract: The effects of pharmacological hypoxia-inducible factor (HIF stabilization were investigated in the MMTV-Neundl-YD5 (NeuYD mouse model of breast cancer. This study first confirmed the sensitivity of this model to increased vascular endothelial growth factor (VEGF, using bigenic NeuYD;MMTV-VEGF-25 mice. Tumor initiation was dramatically accelerated in bigenic animals. Bigenic tumors were also more aggressive, with shortened doubling times and increased lung metastasis as compared to NeuYD controls. In separate studies, NeuYD mice were treated three times weekly from 7 weeks of age until study end with two different HIF prolyl hydroxylase inhibitors (HIF-PHIs, FG-4497 or roxadustat (FG-4592. In NeuYD mice, HIF-PHI treatments elevated erythropoiesis markers, but no differences were detected in tumor onset or the phenotypes of established tumors. Keywords: cancer progression, erythropoiesis, hypoxia-inducible factor, hypoxia-inducible factor prolyl hydroxylase inhibitors, vascular endothelial growth factor, MMTV-Neu breast cancer model

  9. Therapeutic effect of intra-articular injection of ribbon-type decoy oligonucleotides for hypoxia inducible factor-1 on joint contracture in an immobilized knee animal model.

    Science.gov (United States)

    Sotobayashi, Daisuke; Kawahata, Hirohisa; Anada, Natsuki; Ogihara, Toshio; Morishita, Ryuichi; Aoki, Motokuni

    2016-08-01

    Limited range of motion (ROM) as a result of joint contracture in treatment associated with joint immobilization or motor paralysis is a critical issue. However, its molecular mechanism has not been fully clarified and a therapeutic approach is not yet established. In the present study, we investigated its molecular mechanism, focusing on the role of a transcription factor, hypoxia inducible factor-1 (HIF-1), which regulates the expression of connective tissue growth factor (CTGF) and vascular endothelial growth factor (VEGF), and evaluated the possibility of molecular therapy to inhibit HIF-1 activation by ribbon-type decoy oligonucleotides (ODNs) for HIF-1 using immobilized knee animal models. In a mouse model, ROM of the immobilized knee significantly decreased in a time-dependent manner, accompanied by synovial hypertrophy. Immunohistochemical studies suggested that CTGF and VEGF are implicated in synovial hypertrophy with fibrosis. CTGF and VEGF were up-regulated at both the mRNA and protein levels at 1 and 2 weeks after immobilization, subsequent to up-regulation of HIF-1 mRNA and transcriptional activation of HIF-1. Of importance, intra-articular transfection of decoy ODNs for HIF-1 in a rat model successfully inhibited transcriptional activation of HIF-1, followed by suppression of expression of CTGF and VEGF, resulting in attenuation of restricted ROM, whereas transfection of scrambled decoy ODNs did not. The present study demonstrates the important role of HIF-1 in the initial progression of immobilization-induced joint contracture, and indicates the possibility of molecular treatment to prevent the progression of joint contracture prior to intervention with physical therapy. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  10. 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.

  11. 低氧诱导因子与低氧性肺动脉高压形成机制的相关研究%Relationship between hypoxia inducible factor-1 and mechanism of hypoxic pulmonary hypertension

    Institute of Scientific and Technical Information of China (English)

    张凌云; 欧敏

    2010-01-01

    Hypoxia inducible factor-1 is the key regulator of cellular adaptation to hypoxia conditions and various pathological stimuli. It enables cells to exist in low oxygen conditions by mediating the transcription and signal transduction of target genes and plays a crucial role in the development of hypoxic pulmonary hypertension,leukemia,inflammation, cancer and so on. Recent studies have found that hypoxia inducible factor-1 is closely associated with the mechanisms of hypoxic pulmonary hypertension including disorder of ion channel, imbalance of vasoactive substances, increased inflammation and pulmonary vascular remodeling. The article will make a summary of latest research on structure of hypoxia-inducible factor and mechanism of hypoxic pulmonary hypertension.%低氧诱导因子(hypoxia inducible factor-1,HIF-1)是细胞为适应缺氧环境和各种病理刺激所表达的核心调控因子,可调控多种与低氧条件下细胞生存相关靶基因的转录和信号的转导,在低氧性肺动脉高压、白血病、炎症、肿瘤等多种疾病的发生发展过程中起着重要的作用.近年来研究发现,HIF-1与低氧性肺动脉高压形成机制中离子通道的紊乱、血管活性物质的失衡、炎症的加重、肺血管的重塑等密切相关.本文将对低氧诱导因子的结构特征及其与低氧性肺动脉高压形成机制的最新研究概况作一综述.

  12. Reverse translation of phase I biomarker findings links the activity of angiotensin-(1–7 to repression of hypoxia inducible factor-1α in vascular sarcomas

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    Petty W

    2012-09-01

    Full Text Available Abstract Background In a phase I study of angiotensin-(1–7 [Ang-(1–7], clinical benefit was associated with reduction in plasma placental growth factor (PlGF concentrations. The current study examines Ang-(1–7 induced changes in biomarkers according to cancer type and investigates mechanisms of action engaged in vitro. Methods Plasma biomarkers were measured prior to Ang-(1–7 administration as well as 1, 2, 3, 4, and 6 hours after treatment. Tests for interaction were performed to determine the impact of cancer type on angiogenic hormone levels. If a positive interaction was detected, treatment-induced biomarker changes for individual cancer types were assessed. To investigate mechanisms of action, in vitro growth assays were performed using a murine endothelioma cell line (EOMA. PCR arrays were performed to identify and statistically validate genes that were altered by Ang-(1–7 treatment in these cells. Results Tests for interaction controlled for dose cohort and clinical response indicated a significant impact of cancer type on post-treatment VEGF and PlGF levels. Following treatment, PlGF levels decreased over time in patients with sarcoma (P = .007. Treatment of EOMA cells with increasing doses of Ang-(1–7 led to significant growth suppression at doses as low as 100 nM. PCR arrays identified 18 genes that appeared to have altered expression after Ang-(1–7 treatment. Replicate analyses confirmed significant changes in 8 genes including reduction in PlGF (P = .04 and hypoxia inducible factor 1α (HIF-1α expression (P  Conclusions Ang-(1–7 has clinical and pre-clinical activity for vascular sarcomas that is linked to reduced HIF-1α and PlGF expression.

  13. Short-term treatment with glucosamine hydrochloride specifically downregulates hypoxia-inducible factor-1α at the protein level in YD-8 human tongue cancer cells.

    Science.gov (United States)

    Jo, Jeong-Rang; Park, Yu-Kyoung; Jang, Byeong-Churl

    2014-05-01

    Hypoxia-inducible factor-1 (HIF-1) is a tumor angiogenic transcription factor composed of an α and β subunit. We investigated the effect of glucosamine hydrochloride (GS-HCl) on the expression of HIF-1α and HIF-1β in serum‑treated YD-8 human tongue cancer cells. While long-term (24 h) treatment with GS-HCl strongly repressed the expression of HIF-1α and HIF-1β at both the protein and mRNA levels, short-term (4 h) GS-HCl treatment inhibited HIF-1α at the protein level. Short-term GS-HCl treatment also decreased phosphorylation of p70S6K and S6, translation-related proteins. However, the results of subsequent pharmacological inhibition and protein stability analyses indicated that HIF-1α protein downregulation induced by short-term GS-HCl treatment was not through modulation of the mTOR/p70S6K/S6 signaling pathways, the 26S proteasomal and lysosomal activities and HIF-1α protein stability. Importantly, our further analyses identified that HIF-1α protein downregulation induced by short-term GS-HCl treatment was blunted by exogenous administration of the citric acid cycle metabolites citrate and 2-oxoglutarate, but not the glycolytic end byproducts pyruvate and lactate. These findings demonstrate firstly that short-term GS treatment selectively downregulates HIF-1α at the protein level in YD-8 cells via interference of production of the citric acid cycle metabolites. It is proposed that short-term GS-HCl exposure may be applied for the treatment of oral tumors with high expression of HIF-1α.

  14. Increased Tumor Ascorbate is Associated with Extended Disease-Free Survival and Decreased Hypoxia-Inducible Factor-1 Activation in Human Colorectal Cancer.

    Science.gov (United States)

    Kuiper, Caroline; Dachs, Gabi U; Munn, Delwyn; Currie, Margaret J; Robinson, Bridget A; Pearson, John F; Vissers, Margreet C M

    2014-01-01

    Ascorbate is a co-factor for the hydroxylases that regulate the transcription factor hypoxia-inducible factor (HIF)-1, which provides cancer cells with a metabolic and survival advantage in the hypoxic environment of solid tumors. However, whether ascorbate affects tumor development is a highly debated issue. We aimed to determine whether tumor ascorbate was associated with HIF-1 activation and patient disease-free survival. In this study, we undertook a retrospective observational analysis of tissue-banked tumor and paired normal tissue from 49 colorectal cancer patients, measuring ascorbate levels, HIF-1α and its downstream gene products BNIP3, and vascular endothelial cell growth factor (VEGF). Patient survival was monitored for the first 6 years after surgery. We found that ascorbate levels were lower in tumor tissue compared to normal tissue (p ascorbate content and HIF-1 pathway activation (p = 0.002) and tumor size (p = 0.018). Higher tumor ascorbate content was associated with significantly improved disease-free survival in the first 6 years after surgery (p = 0.006), with 141-1,094 additional disease-free days. This was independent of tumor grade and stage. Survival advantage was associated with the amount of ascorbate in the tumor, but not with the amount in adjacent normal tissue. Our results demonstrate that higher tumor ascorbate content is associated with decreased HIF-1 activation, most likely due to the co-factor activity of ascorbate for the regulatory HIF hydroxylases. Our findings support the need for future studies to determine whether raising tumor ascorbate is possible with clinical intervention and whether this results in modification of hydroxylase-dependent pathways in the tumor.

  15. Self-renewal and pluripotency is maintained in human embryonic stem cells by co-culture with human fetal liver stromal cells expressing hypoxia inducible factor 1alpha.

    Science.gov (United States)

    Ji, Lei; Liu, Yu-xiao; Yang, Chao; Yue, Wen; Shi, Shuang-shuang; Bai, Ci-xian; Xi, Jia-fei; Nan, Xue; Pei, Xue-Tao

    2009-10-01

    Human embryonic stem (hES) cells are typically maintained on mouse embryonic fibroblast (MEF) feeders or with MEF-conditioned medium. However, these xenosupport systems greatly limit the therapeutic applications of hES cells because of the risk of cross-transfer of animal pathogens. The stem cell niche is a unique tissue microenvironment that regulates the self-renewal and differentiation of stem cells. Recent evidence suggests that stem cells are localized in the microenvironment of low oxygen. We hypothesized that hypoxia could maintain the undifferentiated phenotype of embryonic stem cells. We have co-cultured a human embryonic cell line with human fetal liver stromal cells (hFLSCs) feeder cells stably expressing hypoxia-inducible factor-1 alpha (HIF-1alpha), which is known as the key transcription factor in hypoxia. The results suggested HIF-1alpha was critical for preventing differentiation of hES cells in culture. Consistent with this observation, hypoxia upregulated the expression of Nanog and Oct-4, the key factors expressed in undifferentiated stem cells. We further demonstrated that HIF-1alpha could upregulate the expression of some soluble factors including bFGF and SDF-1alpha, which are released into the microenvironment to maintain the undifferentiated status of hES cells. This suggests that the targets of HIF-1alpha are secreted soluble factors rather than a cell-cell contact mechanism, and defines an important mechanism for the inhibition of hESCs differentiation by hypoxia. Our findings developed a transgene feeder co-culture system and will provide a more reliable alternative for future therapeutic applications of hES cells.

  16. Increased tumour ascorbate is associated with extended disease-free survival and decreased hypoxia-inducible factor-1 activation in human colorectal cancer

    Directory of Open Access Journals (Sweden)

    Caroline eKuiper

    2014-02-01

    Full Text Available Ascorbate is a co-factor for the hydroxylases that regulate the transcription factor hypoxia-inducible factor (HIF-1, which provides cancer cells with a metabolic and survival advantage in the hypoxic environment of solid tumors. However, whether ascorbate affects tumor development is a highly debated issue. We aimed to determine whether tumor ascorbate was associated with HIF-1 activation and patient disease-free survival. In this study we undertook a retrospective observational analysis of tissue-banked tumor and paired normal tissue from 49 colorectal cancer patients, measuring ascorbate levels, HIF-1α and its downstream gene products BNIP3 and VEGF. Patient survival was monitored for the first six years after surgery. We found that ascorbate levels were lower in tumor tissue compared to normal tissue (p< 0.001 but overall levels varied considerably. HIF-1α, VEGF and BNIP3 were elevated in tumor samples (p< 0.01. There was an inverse relationship between tumor ascorbate content and HIF-1 pathway activation (p=0.002 and tumor size (p=0.018. Higher tumor ascorbate content was associated with significantly improved disease-free survival in the first 6 years after surgery (p=0.006, with 141 - 1,094 additional disease free days. This was independent of tumor grade and stage. Survival advantage was associated with the amount of ascorbate in the tumor, but not with the amount in adjacent normal tissue. Our results demonstrate that higher tumor ascorbate content is associated decreased HIF-1 activation, most likely due to the co-factor activity of ascorbate for the regulatory HIF hydroxylases. Our findings support the need for future studies to determine whether raising tumor ascorbate is possible with clinical intervention and whether this results in modification of hydroxylase-dependent pathways in the tumor.

  17. Molecular characterization and in vivo expression of hypoxia inducible factor (HIF-1α in sea bass (Dicentrarchus labrax exposed to acute and chronic hypoxi

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    Marco Saroglia

    2010-01-01

    Full Text Available Aquatic hypoxia is a frequent event and in fish a complex set of physiological and bi- ochemical alterations are employed to cope with this environmental stress. Many of these adjustments depend to a large extent on changes in the expression of genes that encode for physiologically relevant proteins. Genes that are induced by hypoxia appear to share a common mode of transcriptional regula- tion. This induction depends upon activation of a transcription factor, the hypoxia inducible factor-1 (HIF-1, which is a heterodimer composed of two subunits: α ‧ and β. In this study we report first on the molecular cloning and characterization of HIF-1α ‧ in sea bass (Dicentrarchus labrax. The full-length sea bass cDNA for HIF-1α was isolated and deposited in the GenBank with accession no. DQ171936. It consists of 3317 base pairs (bp carrying a single open-read- ing frame that encompasses 2265 bp of the coding region and 1052 bp of the 3’ UTR. We then utilized the real-time PCR technology to monitor dynamic changes in levels of HIF-1α ‧ tran- scripts, in response to acute and chronic hypoxic stress. The number of HIF-1α ‧ mRNA copies were signifi- cantly increased in response to both acute (1.9 mg/L, dissolved oxygen for 4 hours and chronic (4.3 mg/L, DO for 15 days hypoxia in sea bass, whereas it remained unchanged in fish exposed to hyperoxic (DO 13.5±1.2 mg/L, 155 % saturation conditions. This is the first study carried out to investigate the behaviour of HIF-1α gene transcripts during hypoxia in representative of marine hypoxia-sensitive fish species.

  18. The novel hypoxic cytotoxin, TX-2098 has antitumor effect in pancreatic cancer; possible mechanism through inhibiting VEGF and hypoxia inducible factor-1α targeted gene expression.

    Science.gov (United States)

    Miyake, Kotaro; Nishioka, Masanori; Imura, Satoru; Batmunkh, Erdenebulgan; Uto, Yoshihiro; Nagasawa, Hideko; Hori, Hitoshi; Shimada, Mitsuo

    2012-08-01

    Tumor hypoxia has been considered to be a potential therapeutic target, because hypoxia is a common feature of solid tumors and is associated with their malignant phenotype. In the present study, we investigated the antitumor effect of a novel hypoxic cytotoxin, 3-[2-hydroxyethyl(methyl)amino]-2-quinoxalinecarbonitrile 1,4-dioxide (TX-2098) in inhibiting the expression of hypoxia inducible factor-1α (HIF-1α), and consequently vascular endothelial cell growth factor (VEGF) expression in pancreatic cancer. The antitumor effects of TX-2098 under hypoxia were tested against various human pancreatic cancer cell lines using WST-8 assay. VEGF protein induced pancreatic cancer was determined on cell-free supernatant by ELISA. Moreover, nude mice bearing subcutaneously (s.c.) or orthotopically implanted human SUIT-2 were treated with TX-2098. Tumor volume, survival and expression of HIF-1 and associated molecules were evaluated in treatment versus control groups. In vitro, TX-2098 inhibited the proliferation of various pancreatic cancer cell lines. In s.c model, tumors from nude mice injected with pancreatic cancer cells and treated with TX-2098 showed significant reductions in volume (P<0.01 versus control). Quantitative real-time reverse transcription-PCR analysis revealed that TX-2098 significantly inhibited mRNA expression of the HIF-1 associated molecules, VEGF, glucose transporter 1 and Aldolase A (P<0.01 versus control). These treatments also prolong the survival in orthotopic models. These results suggest that the effect of TX-2098 in pancreatic cancer might be correlated with the expression of VEGF and HIF-1 targeted molecules.

  19. Suppression of hypoxia-inducible factor-1α contributes to the antiangiogenic activity of red propolis polyphenols in human endothelial cells.

    Science.gov (United States)

    Daleprane, Julio B; Schmid, Tobias; Dehne, Nathalie; Rudnicki, Martina; Menrad, Heidi; Geis, Theresa; Ikegaki, Masaharu; Ong, Thomas P; Brüne, Bernhard; Abdalla, Dulcineia S P

    2012-03-01

    Polyphenol-enriched fractions from natural sources have been proposed to interfere with angiogenesis in pathological conditions. We recently reported that red propolis polyphenols (RPP) exert antiangiogenic activity. However, molecular mechanisms of this activity remain unclear. Here, we aimed at characterizing molecular mechanisms to explain the impact of RPP on endothelial cells' (EC) physiology. We used in vitro and ex and in vivo models to test the hypothesis that RPP inhibit angiogenesis by affecting hypoxia-inducible factor-1α (HIF1α) stabilization in EC. RPP (10 mg/L) affected angiogenesis by reducing migration and sprouting of EC, attenuated the formation of new blood vessels, and decreased the differentiation of embryonic stem cells into CD31-positive cells. Moreover, RPP (10 mg/L) inhibited hypoxia- or dimethyloxallylglycine-induced mRNA and protein expression of the crucial angiogenesis promoter vascular endothelial growth factor (VEGF) in a time-dependent manner. Under hypoxic conditions, RPP at 10 mg/L, supplied for 1-4 h, decreased HIF1α protein accumulation, which in turn attenuated VEGF gene expression. In addition, RPP reduced the HIF1α protein half-life from ~58 min to 38 min under hypoxic conditions. The reduced HIF1α protein half-life was associated with an increase in the von Hippel-Lindau (pVHL)-dependent proteasomal degradation of HIF1α. RPP (10 mg/L, 4 h) downregulated Cdc42 protein expression. This caused a corresponding increase in pVHL protein levels and a subsequent degradation of HIF1α. In summary, we have elucidated the underlying mechanism for the antiangiogenic action of RPP, which attenuates HIF1α protein accumulation and signaling.

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

    Science.gov (United States)

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

    2011-02-01

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

  1. Chronic intermittent hypoxia-induced deficits in synaptic plasticity and neurocognitive functions: a role for brain-derived neurotrophic factor

    Institute of Scientific and Technical Information of China (English)

    Hui XIE; Wing-ho YUNG

    2012-01-01

    Obstructive sleep apnea (OSA) is well known for its metabolic as well as neurobehavioral consequences.Chronic intermittent hypoxia (IH) is a major component of OSA.In recent years,substantial advances have been made in elucidating the cellular and molecular mechanisms underlying the effect of chronic IH on neurocognitive functions,many of which are based on studies in animal models.A number of hypotheses have been put forward to explain chronic IH-induced neurological dysfunctions.Among these,the roles of oxidative stress and apoptosis-related neural injury are widely accepted.Here,focusing on results derived from animal studies,we highlight a possible role of reduced expression of brain-derived neurotrophic factor (BDNF) in causing impairment in long-term synaptic plasticity and neurocognitive functions during chronic IH.The possible relationship between BDNF and previous findings on this subject will be elucidated.

  2. Hypoxia-inducible factor-1 and diabetic complications%低氧诱导因子-1与糖尿病并发症

    Institute of Scientific and Technical Information of China (English)

    阳诚; 南庆玲; 徐勇

    2010-01-01

    The pathogenesis of diabetic complications is related to many factors, including genetic susceptibility, glycometabolism disorder,oxidative stress and so on. But the pathogenesis is not so clear. Recent researches show that diabetic complications are closely related to hypoxia,and hypoxia-inducible factor-1 ( HIF-1 ) is an important factor for transcriptional control. HIF-1 participates in angiogenesis, energy metabolism, apoptosis and so on, through controlling the downstream transcription of genes in order to adapt hypoxia environment. Discussing the structure ,function adjustment and effect in diabetic complication of HIF-1, studying how to maintain moderate expression of HIF-1 ,can provide a new method for prevention of diabetic complications.%糖尿病并发症的发病机制涉及多个因素,与遗传易感性、糖代谢紊乱、氧化应激等密切相关,但具体机制尚未明确.近年研究发现其发病过程与低氧密切相关,而低氧诱导因子-1(HIF-1)是缺氧时重要的转录调控因子,可通过对下游基因的转录调控参与血管发生、能量代谢、细胞凋亡等病理生理过程,以适应低氧环境.探讨HIF-1结构和功能的调节及其在糖尿病并发症中的作用,研究如何维持HIF-1的适度表达,为防治糖尿病并发症提供了新的思路.

  3. Intermittent Hypoxia Influences Alveolar Bone Proper Microstructure via Hypoxia-Inducible Factor and VEGF Expression in Periodontal Ligaments of Growing Rats

    Science.gov (United States)

    Oishi, Shuji; Shimizu, Yasuhiro; Hosomichi, Jun; Kuma, Yoichiro; Maeda, Hideyuki; Nagai, Hisashi; Usumi-Fujita, Risa; Kaneko, Sawa; Shibutani, Naoki; Suzuki, Jun-ichi; Yoshida, Ken-ichi; Ono, Takashi

    2016-01-01

    Intermittent hypoxia (IH) recapitulates morphological changes in the maxillofacial bones in children with obstructive sleep apnea (OSA). Recently, we found that IH increased bone mineral density (BMD) in the inter-radicular alveolar bone (reflecting enhanced osteogenesis) in the mandibular first molar (M1) region in the growing rats, but the underlying mechanism remains unknown. In this study, we focused on the hypoxia-inducible factor (HIF) pathway to assess the effect of IH by testing the null hypothesis of no significant differences in the mRNA-expression levels of relevant factors associated with the HIF pathway, between control rats and growing rats with IH. To test the null hypothesis, we investigated how IH enhances mandibular osteogenesis in the alveolar bone proper with respect to HIF-1α and vascular endothelial growth factor (VEGF) in periodontal ligament (PDL) tissues. Seven-week-old male Sprague–Dawley rats were exposed to IH for 3 weeks. The microstructure and BMD in the alveolar bone proper of the distal root of the mandibular M1 were evaluated using micro-computed tomography (micro-CT). Expression of HIF-1α and VEGF mRNA in PDL tissues were measured, whereas osteogenesis was evaluated by measuring mRNA levels for alkaline phosphatase (ALP) and bone morphogenetic protein-2 (BMP-2). The null hypothesis was rejected: we found an increase in the expression of all of these markers after IH exposure. The results provided the first indication that IH enhanced osteogenesis of the mandibular M1 region in association with PDL angiogenesis during growth via HIF-1α in an animal model. PMID:27695422

  4. Intermittent Hypoxia Influences Alveolar Bone Proper Microstructure via Hypoxia-Inducible Factor and VEGF Expression in Periodontal Ligaments of Growing Rats

    Directory of Open Access Journals (Sweden)

    Shuji Oishi

    2016-09-01

    Full Text Available Intermittent hypoxia (IH recapitulates morphological changes in the maxillofacial bones in children with obstructive sleep apnea (OSA. Recently, we found that IH increased bone mineral density (BMD in the inter-radicular alveolar bone (reflecting enhanced osteogenesis in the mandibular first molar (M1 region in the growing rats, but the underlying mechanism remains unknown. In this study, we focused on the hypoxia-inducible factor (HIF pathway to assess the effect of IH by testing the null hypothesis of no significant differences in the mRNA-expression levels of relevant factors associated with the HIF pathway, between control rats and growing rats with IH. To test the null hypothesis, we investigated how IH enhances mandibular osteogenesis in the alveolar bone proper with respect to HIF-1α and vascular endothelial growth factor (VEGF in periodontal ligament (PDL tissues. Seven-week-old male Sprague–Dawley rats were exposed to IH for 3 weeks. The microstructure and BMD in the alveolar bone proper of the distal root of the mandibular M1 were evaluated using micro-computed tomography (micro-CT. Expression of HIF-1α and VEGF mRNA in PDL tissues were measured, whereas osteogenesis was evaluated by measuring mRNA levels for alkaline phosphatase (ALP and bone morphogenetic protein-2 (BMP-2. The null hypothesis was rejected: we found an increase in the expression of all of these markers after IH exposure. The results provided the first indication that IH enhanced osteogenesis of the mandibular M1 region in association with PDL angiogenesis during growth via HIF-1α in an animal model.

  5. RNA interference targeting hypoxia-inducible factor 1α via a novel multifunctional surfactant attenuates glioma growth in an intracranial mouse model.

    Science.gov (United States)

    Gillespie, David L; Aguirre, Maria T; Ravichandran, Sandhya; Leishman, Lisa L; Berrondo, Claudia; Gamboa, Joseph T; Wang, Libo; King, Rose; Wang, Xuli; Tan, Mingqian; Malamas, Anthony; Lu, Zheng-Rong; Jensen, Randy L

    2015-02-01

    High-grade gliomas are the most common form of adult brain cancer, and patients have a dismal survival rate despite aggressive therapeutic measures. Intratumoral hypoxia is thought to be a main contributor to tumorigenesis and angiogenesis of these tumors. Because hypoxia-inducible factor 1α (HIF-1α) is the major mediator of hypoxia-regulated cellular control, inhibition of this transcription factor may reduce glioblastoma growth. Using an orthotopic mouse model with U87-LucNeo cells, the authors used RNA interference to knock down HIF-1α in vivo. The small interfering RNA (siRNA) was packaged using a novel multifunctional surfactant, 1-(aminoethyl) iminobis[N-(oleicylcysteinylhistinyl-1-aminoethyl)propionamide] (EHCO), a nucleic acid carrier that facilitates cellular uptake and intracellular release of siRNA. Stereotactic injection was used to deliver siRNA locally through a guide-screw system, and delivery/uptake was verified by imaging of fluorescently labeled siRNA. Osmotic pumps were used for extended siRNA delivery to model a commonly used human intracranial drug-delivery technique, convection-enhanced delivery. Mice receiving daily siRNA injections targeting HIF-1α had a 79% lower tumor volume after 50 days of treatment than the controls. Levels of the HIF-1 transcriptional targets vascular endothelial growth factor (VEGF), glucose transporter 1 (GLUT-1), c-MET, and carbonic anhydrase-IX (CA-IX) and markers for cell growth (MIB-1 and microvascular density) were also significantly lower. Altering the carrier EHCO by adding polyethylene glycol significantly increased the efficacy of drug delivery and subsequent survival. Treating glioblastoma with siRNA targeting HIF-1α in vivo can significantly reduce tumor growth and increase survival in an intracranial mouse model, a finding that has direct clinical implications.

  6. Hypoxia-induced modulation of PTEN activity and EMT phenotypes in lung cancers.

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    Kohnoh, Takashi; Hashimoto, Naozumi; Ando, Akira; Sakamoto, Koji; Miyazaki, Shinichi; Aoyama, Daisuke; Kusunose, Masaaki; Kimura, Motohiro; Omote, Norihito; Imaizumi, Kazuyoshi; Kawabe, Tsutomu; Hasegawa, Yoshinori

    2016-01-01

    Persistent hypoxia stimulation, one of the most critical microenvironmental factors, accelerates the acquisition of epithelial-mesenchymal transition (EMT) phenotypes in lung cancer cells. Loss of phosphatase and tensin homologue deleted from chromosome 10 (PTEN) expression might accelerate the development of lung cancer in vivo. Recent studies suggest that tumor microenvironmental factors might modulate the PTEN activity though a decrease in total PTEN expression and an increase in phosphorylation of the PTEN C-terminus (p-PTEN), resulting in the acquisition of the EMT phenotypes. Nevertheless, it is not known whether persistent hypoxia can modulate PTEN phosphatase activity or whether hypoxia-induced EMT phenotypes are negatively regulated by the PTEN phosphatase activity. We aimed to investigate hypoxia-induced modulation of PTEN activity and EMT phenotypes in lung cancers. Western blotting was performed in five lung cancer cell lines to evaluate total PTEN expression levels and the PTEN activation. In a xenograft model of lung cancer cells with endogenous PTEN expression, the PTEN expression was evaluated by immunohistochemistry. To examine the effect of hypoxia on phenotypic alterations in lung cancer cells in vitro, the cells were cultured under hypoxia. The effect of unphosphorylated PTEN (PTEN4A) induction on hypoxia-induced EMT phenotypes was evaluated, by using a Dox-dependent gene expression system. Lung cancer cells involving the EMT phenotypes showed a decrease in total PTEN expression and an increase in p-PTEN. In a xenograft model, loss of PTEN expression was observed in the tumor lesions showing tissue hypoxia. Persistent hypoxia yielded an approximately eight-fold increase in the p-PTEN/PTEN ratio in vitro. PTEN4A did not affect stabilization of hypoxia-inducible factor 1α. PTEN4A blunted hypoxia-induced EMT via inhibition of β-catenin translocation into the cytoplasm and nucleus. Our study strengthens the therapeutic possibility that

  7. 1α, 25-Dihydroxyvitamin D regulates hypoxia-inducible factor-1α in untransformed and Harvey-ras transfected breast epithelial cells.

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    Jiang, Yan; Zheng, Wei; Teegarden, Dorothy

    2010-12-01

    The purpose of this study was to determine the mechanism by which 1α, 25-dihydroxyvitamin D (1,25(OH)(2)D) alters hypoxia-inducible factor-1α (HIF-1α) protein in untransformed and Harvey-ras (H-ras) oncogene transfected MCF10A breast epithelial cells. Treatment with 1,25(OH)(2)D (10nM) increased both mRNA (2.55±0.6-fold vs. vehicle, p=0.03) and protein levels (2.37±0.3-fold vs. vehicle, pMCF10A cells in 12h, which remained elevated at 24h. However, in H-ras transfected MCF10A cells, 1,25(OH)(2)D treatment increased HIF-1α protein level (2.08±0.38-fold vs. vehicle, p=0.05) at 12h, with no change in mRNA level and HIF-1α protein level returned to baseline after 24h. A transcription inhibitor prevented the 1,25(OH)(2)D induction of HIF-1α protein and mRNA levels in MCF10A cells, but failed to alter the induction of HIF-1α protein level in H-ras transfected MCF10A cells. On the other hand, inhibition of proteasomal degradation prevented the 1,25(OH)(2)D-induced HIF-1α protein level in H-ras transfected MCF10A but not in MCF10A cells. These results support that 1,25(OH)(2)D regulates HIF-1α protein level via transcriptional regulation in MCF10A cells in contrast to through proteosomal degradation with the presence of H-ras oncogene in MCF10A cells.

  8. Hypoxia inducible factor-1 alpha expression is increased in infected positive HPV16 DNA oral squamous cell carcinoma and positively associated with HPV16 E7 oncoprotein

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    Di Fede Olga

    2011-10-01

    Full Text Available Abstract Background There is increasing evidence for the role of High Risk (HR Human PapillomaVirus (HPV in the pathogenesis of Oral Squamous Cell Carcinoma (OSCC. The E6 and E7 oncogenes from HR HPVs are responsible for the deregulation of p53 and pRB proteins involved in cell cycle and apoptotic pathways. In cell lines experiments, the HPV E7 protein seems to be able to enhance Hypoxia Inducible Factor-1 alpha (HIF-1α activity, normally involved in the response to hypoxia and able to enhance angiogenesis. Results We studied tumor specimens from 62 OSCC; a higher prevalence of tumors in TNM stage II and also in pT2 class between OSCC infected positive HPV16 DNA than non-infected ones was observed. HIF-1α positivity was detected throughout the analysed fields, not associated with areas of necrosis and also observed in cells immediately adjacent to blood vessels. A significant increase in mean values of the HIF-1α labeling indexes was observed for pT1-T2, as well for stage I-II, in the infected positive HPV16 DNA tumors than non-infected ones. HIF-1α and HPV16 E7 labeling indexes showed a significantly positive correlation which suggested a positive association between HPV16 E7 and HIF-1α expression. Conclusions In our specimens HIF-1α immunoreactivity hints for an O2-independent regulatory mechanism in infected positive HPV16 DNA tumors, especially for pT1-T2 and stage I-II tumors, suggesting a very early involvement in the development of HPV-induced OSCC. HIF-1α and HPV16 E7 labeling indexes suggest also a positive association between the two proteins in infected positive HPV16 DNA OSCC.

  9. Repairing critical-sized calvarial defects with BMSCs modified by a constitutively active form of hypoxia-inducible factor-1α and a phosphate cement scaffold.

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    Zou, Duohong; Zhang, Zhiyuan; He, Jiacai; Zhu, Siheng; Wang, Shaoyi; Zhang, Wenjie; Zhou, Jian; Xu, Yuanjin; Huang, Yan; Wang, Yuanyin; Han, Wei; Zhou, Yong; Wang, Shuhong; You, Sulan; Jiang, Xinquan; Huang, Yuanliang

    2011-12-01

    Tissue engineering combined with gene therapy represents a promising approach for bone regeneration. The Hypoxia-inducible factor-1α (HIF-1α) gene is a pivotal regulator of vascular reactivity and angiogenesis. Our recent study has showed that HIF-1α could promote osteogenesis of bone mesenchymal stem cells (BMSCs) using a gene point mutant technique. To optimize the function of HIF-1α on inducing stem cells, another constitutively active form of HIF-1α (CA5) was constructed with truncation mutant method and its therapeutic potential on critical-sized bone defects was evaluated with calcium-magnesium phosphate cement (CMPC) scaffold in a rat model. BMSCs were treated with Lenti (lentivirus) -CA5, Lenti-WT (wild-type HIF-1α), and Lenti-LacZ. These genetically modified BMSCs were then combined with CMPC scaffolds to repair critical-sized calvarial defects in rats. The results showed that the overexpression of HIF-1α obviously enhanced the mRNA and protein expression of osteogenic markers in vitro and robust new bone formation with the higher local bone mineral density (BMD) was found in vivo in the CA5 and WT groups. Furthermore, CA5 showed significantly greater stability and osteogenic activity in BMSCs compared with WT. These data suggest that BMSCs transduced with truncation mutanted HIF-1α gene can promote the overexpression of osteogenic markers. CMPC could serve as a potential substrate for HIF-1α gene modified tissue engineered bone to repair critical sized bony defects.

  10. NNC 55-0396, a T-type Ca2+ channel inhibitor, inhibits angiogenesis via suppression of hypoxia-inducible factor-1α signal transduction.

    Science.gov (United States)

    Kim, Ki Hyun; Kim, Dongyoung; Park, Ju Yeol; Jung, Hye Jin; Cho, Yong-Hee; Kim, Hyoung Kyu; Han, Jin; Choi, Kang-Yell; Kwon, Ho Jeong

    2015-05-01

    Mitochondrial respiration is required for hypoxia-inducible factor (HIF)-1α stabilization, which is important for tumor cell survival, proliferation, and angiogenesis. Herein, small molecules that inhibit HIF-1α protein stability by targeting mitochondrial energy production were screened using the Library of Pharmacologically Active Compounds and cell growth assay in galactose or glucose medium. NNC 55-0396, a T-type Ca(2+) channel inhibitor, was selected as a hit from among 1,280 small molecules. NNC 55-0396 suppressed mitochondrial reactive oxygen species-mediated HIF-1α expression as well as stabilization by inhibiting protein synthesis in a dose-dependent manner. NNC 55-0396 inhibited tumor-induced angiogenesis in vitro and in vivo by suppressing HIF-1α stability. Moreover, NNC 55-0396 significantly suppressed glioblastoma tumor growth in a xenograft model. Thus, NNC 55-0396, a small molecule targeting T-type Ca(2+) channel, was identified by the systemic cell-based assay and was shown to have antiangiogenic activity via the suppression of HIF-1α signal transduction. These results provide new insights into the biological network between ion channel and HIF-1α signal transduction. HIF-1α overexpression has been demonstrated in hypoxic cancer cells. NNC 55-0396, a T-type Ca(2+) channel inhibitor, inhibited HIF-1α expression via both proteasomal degradation and protein synthesis pathways. T-type Ca(2+) channel inhibitors block angiogenesis by suppressing HIF-1α stability and synthesis. NNC 55-0396 could be a potential therapeutic drug candidate for cancer treatment.

  11. Insights into the therapeutic potential of hypoxia-inducible factor-1α small interfering RNA in malignant melanoma delivered via folate-decorated cationic liposomes

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    Chen Z

    2016-03-01

    Full Text Available Zhongjian Chen,1,* Tianpeng Zhang,2,* Baojian Wu,2 Xingwang Zhang2 1Department of Pharmaceutics, Shanghai Dermatology Hospital, 2Division of Pharmaceutics, College of Pharmacy, Jinan University, Gangzhou, People’s Republic of China *These authors contributed equally to this work Abstract: Malignant melanoma (MM represents the most dangerous form of skin cancer, and its incidence is expected to rise in the coming time. However, therapy for MM is limited by low topical drug concentration and multidrug resistance. This article aimed to develop folate-decorated cationic liposomes (fc-LPs for hypoxia-inducible factor-1α (HIF-1α small interfering (siRNA delivery, and to evaluate the potential of such siRNA/liposome complexes in MM therapy. HIF-1α siRNA-loaded fc-LPs (siRNA-fc-LPs were prepared by a film hydration method followed by siRNA incubation. Folate decoration of liposomes was achieved by incorporation of folate/oleic acid-diacylated oligochitosans. The resulting siRNA-fc-LPs were 95.3 nm in size with a ζ potential of 2.41 mV. The liposomal vectors exhibited excellent loading capacity and protective effect toward siRNA. The in vitro cell transfection efficiency was almost parallel to the commercially available Lipofectamine™ 2000. Moreover, the anti-melanoma activity of HIF-1α siRNA was significantly enhanced through fc-LPs. Western blot analysis and apoptosis test demonstrated that siRNA-fc-LPs substantially reduced the production of HIF-1α-associated protein and induced the apoptosis of hypoxia-tolerant melanoma cells. Our designed liposomal vectors might be applicable as siRNA delivery vehicle to systemically or topically treat MM. Keywords: malignant melanoma, HIF-1α siRNA, chitosan, cationic liposomes, gene therapy

  12. Negative regulation of human growth hormone gene expression by insulin is dependent on hypoxia-inducible factor binding in primary non-tumor pituitary cells.

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    Vakili, Hana; Jin, Yan; Cattini, Peter A

    2012-09-28

    Insulin controls growth hormone (GH) production at multiple levels, including via a direct effect on pituitary somatotrophs. There are no data, however, on the regulation of the intact human (h) GH gene (hGH1) by insulin in non-tumor pituitary cells, but the proximal promoter region (nucleotides -496/+1) responds negatively to insulin in transfected pituitary tumor cells. A DNA-protein interaction was also induced by insulin at nucleotides -308/-235. Here, we confirmed the presence of a hypoxia-inducible factor 1 (HIF-1) binding site within these sequences (-264/-259) and investigated whether HIF-1 is associated with insulin regulation of "endogenous" hGH1. In the absence of primary human pituitary cells, transgenic mice expressing the intact hGH locus in a somatotroph-specific manner were generated. A significant and dose-dependent decrease in hGH and mouse GH RNA levels was detected in primary pituitary cell cultures from these mice with insulin treatment. Increasing HIF-1α availability with a hypoxia mimetic significantly decreased hGH RNA levels and was accompanied by recruitment of HIF-1α to the hGH1 promoter in situ as seen with insulin. Both inhibition of HIF-1 DNA binding by echinomycin and RNA interference of HIF-1α synthesis blunted the negative effect of insulin on hGH1 but not mGH. The insulin response is also sensitive to histone deacetylase inhibition/trichostatin A and associated with a decrease in H3/H4 hyperacetylation in the proximal hGH1 promoter region. These data are consistent with HIF-1-dependent down-regulation of hGH1 by insulin via chromatin remodeling specifically in the proximal promoter region.

  13. Electroacupuncture Pretreatment Attenuates Cerebral Ischemic Injury via Notch Pathway-Mediated Up-Regulation of Hypoxia Inducible Factor-1α in Rats.

    Science.gov (United States)

    Zhao, Yu; Deng, Bin; Li, Yichong; Zhou, Lihua; Yang, Lei; Gou, Xingchun; Wang, Qiang; Chen, Guozhong; Xu, Hao; Xu, Lixian

    2015-11-01

    We have reported electroacupuncture (EA) pretreatment induced the tolerance against focal cerebral ischemia through activation of canonical Notch pathway. However, the underlying mechanisms have not been fully understood. Evidences suggest that up-regulation of hypoxia inducible factor-1α (HIF-1α) contributes to neuroprotection against ischemia which could interact with Notch signaling pathway in this process. Therefore, the current study is to test that up-regulation of HIF-1α associated with Notch pathway contributes to the neuroprotection of EA pretreatment. Sprague-Dawley rats were treated with EA at the acupoint "Baihui (GV 20)" 30 min per day for successive 5 days before MCAO. HIF-1α levels were measured before and after reperfusion. Then, HIF-1α antagonist 2ME2 and γ-secretase inhibitor MW167 were used. Neurologic deficit scores, infarction volumes, neuronal apoptosis, and Bcl2/Bax were evaluated. HIF-1α and Notch1 intracellular domain (NICD) were assessed. The results showed EA pretreatment enhanced the neuronal expression of HIF-1α, reduced infarct volume, improved neurological outcome, inhibited neuronal apoptosis, up-regulated expression of Bcl-2, and down-regulated expression of Bax after reperfusion in the penumbra, while the beneficial effects were attenuated by 2ME2. Furthermore, intraventricular injection with MW167 efficiently suppressed both up-regulation of NICD and HIF-1α after reperfusion. However, administration with 2ME2 could only decrease the expression of HIF-1α in the penumbra. In conclusion, EA pretreatment exerts neuroprotection against ischemic injury through Notch pathway-mediated up-regulation of HIF-1α.

  14. Up-regulation of hypoxia inducible factor-1α by cobalt chloride correlates with proliferation and apoptosis in PC-2 cells

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    Dai Zhi-Jun

    2012-03-01

    Full Text Available Abstract Background The exact mechanism of the effects of hypoxia on the proliferation and apoptosis in carcinoma cells is still conflicting. This study investigated the variation of hypoxia-inducible factor-1α(HIF-1α expression and the apoptosis effect of hypoxia stimulated by cobalt chloride (CoCl2 in pancreatic cancer PC-2 cells. Methods PC-2 cells were cultured with different concentration (50-200 μmol/L of CoCl2 after 24-120 hours to simulate hypoxia in vitro. The proliferation of PC-2 cells was examined by MTT assay. The cellular morphology of PC-2 cells were observed by light inverted microscope and transmission electron microscope(EM. The expression of HIF-1α on mRNA and protein level was measured by semi-quantitive RT-PCR and Western blot analysis. Apoptosis of PC-2 cells were demonstrated by flow cytometry with Annexin V-FITC/PI double staining. Results MTT assay showed that the proliferation of PC-2 cells were stimulated in the first 72 h, while after treated over 72 h, a dose- dependent inhibition of cell growth could be observed. By using transmission electron microscope, swollen chondrosomes, accumulated chromatin under the nuclear membrane and apoptosis bodies were observed. Flow cytometer(FCM analysis showed the apoptosis rate was correlated with the dosage of CoCl2. RT-PCR and Western blot analysis indicated that hypoxia could up-regulate the expression of HIF-1α on both mRNA and protein levels. Conclusion Hypoxic microenvironment stimulated by CoCl2 could effectively induce apoptosis and influence cell proliferation in PC-2 cells, the mechanism could be related to up-expression of HIF-1α.

  15. MiR-338-3p inhibits hepatocarcinoma cells and sensitizes these cells to sorafenib by targeting hypoxia-induced factor 1α.

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    Haitao Xu

    Full Text Available Hypoxia is a common feature of solid tumors and an important contributor to anti-tumor drug resistance. Hypoxia inducible factor-1 (HIF-1 is one of the key mediators of the hypoxia signaling pathway, and was recently proven to be required for sorafenib resistance in hepatocarcinoma (HCC. MicroRNAs have emerged as important posttranslational regulators in HCC. It was reported that miR-338-3p levels are associated with clinical aggressiveness of HCC. However, the roles of miR-338-3p in HCC disease and resistance to its therapeutic drugs are unknown. In this study, we found that miR-338-3p was frequently down-regulated in 14 HCC clinical samples and five cell lines. Overexpression of miR-338-3p inhibited HIF-1α 3'-UTR luciferase activity and HIF-1α protein levels in HepG2, SMMC-7721, and Huh7 cells. miR-338-3p significantly reduced cell viability and induced cell apoptosis of HCC cells. Additionally, HIF-1α overexpression rescued and HIF-1α knock-down abrogated the anti-HCC activity of miR-338-3p. Furthermore, miR-338-3p sensitized HCC cells to sorafenib in vitro and in a HCC subcutaneous nude mice tumor model by inhibiting HIF-1α. Collectively, miR-338-3p inhibits HCC tumor growth and sensitizes HCC cells to sorafenib by down-regulating HIF-1α. Our data indicate that miR-338-3p could be a potential candidate for HCC therapeutics.

  16. Characterization of the activation of protein tyrosine phosphatase, receptor-type, Z polypeptide 1 (PTPRZ1 by hypoxia inducible factor-2 alpha.

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    Victoria Wang

    Full Text Available BACKGROUND: Hypoxia inducible factors (HIFs are the principal means by which cells upregulate genes in response to hypoxia and certain other stresses. There are two major HIFs, HIF-1 and HIF-2. We previously found that certain genes are preferentially activated by HIF-2. One was protein tyrosine phosphatase, receptor-type, Z polypeptide 1 (PTPRZ1. PTPRZ1 is overexpressed in a number of tumors and has been implicated in glioblastoma pathogenesis. METHODOLOGY/PRINCIPAL FINDINGS: To understand the preferential activation of PTPRZ1 by HIF-2, we studied the PTPRZ1 promoter in HEK293T cells and Hep3B cells. Through deletion and mutational analysis, we identified the principal hypoxia response element. This element bound to both HIF-1 and HIF-2. We further identified a role for ELK1, an E26 transformation-specific (Ets factor that can bind to HIF-2alpha but not HIF-1alpha, in the HIF-2 responsiveness. Knock-down experiments using siRNA to ELK1 decreased HIF-2 activation by over 50%. Also, a deletion mutation of one of the two Ets binding motifs located near the principal hypoxia response element similarly decreased activation of the PTPRZ1 promoter by HIF-2. Finally, chromatin immunoprecipitation assays showed binding of HIF and ELK1 to the PTPRZ1 promoter region. CONCLUSIONS/SIGNIFICANCE: These results identify HIF-binding and Ets-binding motifs on the PTPRZ1 promoter and provide evidence that preferential activation of PTPRZ1 by HIF-2 results at least in part from cooperative binding of HIF-2 and ELK1 to nearby sites on the PTPRZ1 promoter region. These results may have implications in tumor pathogenesis and in understanding neurobiology, and may help inform the development of novel tumor therapy.

  17. High Nuclear Hypoxia-Inducible Factor 1 Alpha Expression Is a Predictor of Distant Recurrence in Patients With Resected Pancreatic Adenocarcinoma

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    Colbert, Lauren E. [Department of Radiation Oncology, Emory University, Atlanta, Georgia (United States); Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Fisher, Sarah B. [Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Division of Surgical Oncology, Department of Surgery, Emory University, Atlanta, Georgia (United States); Balci, Serdar; Saka, Burcu [Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Department of Pathology, Emory University, Atlanta, Georgia (United States); Chen, Zhengjia; Kim, Sungjin [Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Biostatistics and Bioinformatics Shared Resource, Emory University, Atlanta, Georgia (United States); El-Rayes, Bassel F. [Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Department of Hematology and Medical Oncology, Emory University, Atlanta, Georgia (United States); Adsay, N. Volkan [Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Department of Pathology, Emory University, Atlanta, Georgia (United States); Biostatistics and Bioinformatics Shared Resource, Emory University, Atlanta, Georgia (United States); Maithel, Shishir K. [Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Division of Surgical Oncology, Department of Surgery, Emory University, Atlanta, Georgia (United States); Biostatistics and Bioinformatics Shared Resource, Emory University, Atlanta, Georgia (United States); Landry, Jerome C. [Department of Radiation Oncology, Emory University, Atlanta, Georgia (United States); Winship Cancer Institute, Emory University, Atlanta, Georgia (United States); Biostatistics and Bioinformatics Shared Resource, Emory University, Atlanta, Georgia (United States); and others

    2015-03-01

    Purpose: To evaluate nuclear hypoxia-inducible factor 1α (HIF-1α) expression as a prognostic factor for distant recurrence (DR) and local recurrence (LR) after pancreatic adenocarcinoma resection. Methods and Materials: Tissue specimens were collected from 98 patients with pancreatic adenocarcinoma who underwent resection without neoadjuvant therapy between January 2000 and December 2011. Local recurrence was defined as radiographic or pathologic evidence of progressive disease in the pancreas, pancreatic bed, or associated nodal regions. Distant recurrence was defined as radiographically or pathologically confirmed recurrent disease in other sites. Immunohistochemical staining was performed and scored by an independent pathologist blinded to patient outcomes. High HIF-1α overall expression score was defined as high percentage and intensity staining and thus score >1.33. Univariate analysis was performed for HIF-1α score with LR alone and with DR. Multivariate logistic regression was used to determine predictors of LR and DR. Results: Median follow-up time for all patients was 16.3 months. Eight patients (8%) demonstrated isolated LR, 26 patients (26.5%) had isolated DR, and 13 patients had both LR and DR. Fifty-three patients (54%) had high HIF-1α expression, and 45 patients (46%) had low HIF-1α expression. High HIF-1α expression was significantly associated with DR (P=.03), and low HIF-1α expression was significantly associated with isolated LR (P=.03). On multivariate logistic regression analysis, high HIF-1α was the only significant predictor of DR (odds ratio 2.46 [95% confidence interval 1.06-5.72]; P=.03). In patients with a known recurrence, an HIF-1α score ≥2.5 demonstrated a specificity of 100% for DR. Conclusions: High HIF-1α expression is a significant predictor of distant failure versus isolated local failure in patients undergoing resection of pancreatic adenocarcinoma. Expression of HIF-1α may have utility in determining candidates for

  18. Hypoxia-Inducible Factor α and Hif-prolyl Hydroxylase Characterization and Gene Expression in Short-Time Air-Exposed Mytilus galloprovincialis.

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    Giannetto, Alessia; Maisano, Maria; Cappello, Tiziana; Oliva, Sabrina; Parrino, Vincenzo; Natalotto, Antonino; De Marco, Giuseppe; Barberi, Chiara; Romeo, Orazio; Mauceri, Angela; Fasulo, Salvatore

    2015-12-01

    Aquatic organisms experience environmental hypoxia as a result of eutrophication and naturally occurring tidal cycles. Mytilus galloprovincialis, being an anoxic/hypoxic-tolerant bivalve, provides an excellent model to investigate the molecular mechanisms regulating oxygen sensing. Across the animal kingdom, inadequacy in oxygen supply is signalled predominantly by hypoxia-inducible factors (HIF) and Hif-prolyl hydroxylases (PHD). In this study, hif-α 5'-end and partial phd mRNA sequences from M. galloprovincialis were obtained. Phylogenetic and molecular characterization of both HIF-α and PHD putative proteins showed shared key features with the respective orthologues from animals strongly suggesting their crucial involvement in the highly conserved oxygen sensing pathway. Both transcripts displayed a tissue-specific distribution with prominent expression in gills. Quantitative gene expression analysis of hif-α and phd mRNAs from gills of M. galloprovincialis demonstrated that both these key sensors are transcriptionally modulated by oxygen availability during the short-time air exposure and subsequent re-oxygenation treatments proving that they are critical players of oxygen-sensing mechanisms in mussels. Remarkably, hif-α gene expression showed a prompt and transient response suggesting the precocious implication of this transcription factor in the early phase of the adaptive response to hypoxia in Mytilus. HIF-α and PHD proteins were modulated in a time-dependent manner with trends comparable to mRNA expression patterns, thus suggesting a central role of their transcriptional regulation in the hypoxia tolerance strategies in marine bivalves. These results provide molecular information about the effects of oxygen deficiency and identify hypoxia-responsive biomarker genes in mussels applicable in ecotoxicological studies of natural marine areas.

  19. The expression of hypoxia-inducible factor-1α and its clinical significance in lung cancer: a systematic review and meta-analysis.

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    Ren, Weiwei; Mi, Denghai; Yang, Kehu; Cao, Nong; Tian, Jinhui; Li, Zheng; Ma, Bin

    2013-09-06

    Hypoxia-inducible factor-1α (HIF-1α) plays an important role in tumour progression and metastasis through activation of many target genes that are especially involved in pivotal aspects of cancer biology. However, the prognostic role of HIF-1α has been controversial in primary patients with lung cancer. This meta-analysis was performed to systematically evaluate whether HIF-1α expression is associated with the clinical outcomes in lung cancer patients. We retrieved relevant articles from Cochrane library, PubMed, EMbase, CNKI, CBM, VIP and Wan Fang Databases from inception to May 2012. Studies were selected using specific inclusion and exclusion criteria. A systematic review and meta-analysis was performed on the association between HIF-1α expression and clinical outcomes in lung cancer patients. All analyses were performed using the Revman 5.1 software. A total of 30 studies were identified as eligible for the systematic review and meta-analysis. The expression of HIF-1α was significantly higher than those in normal lung tissue; and III-IV stage, lymph node metastasis, poorly differentiation, squamous cell carcinoma and small cell lung cancer (SCLC) were significantly higher than those in I-II stage, no lymph node metastasis, well differentiation, adenocarcinomas and non small cell lung cancer (NSCLC), respectively (odds ratio (OR) = 19.00, 95% confidence interval (CI):12.12-29.78, p combines other proteins, such as vascular endothelial growth factor (VEGF) or CA IX, might serve as important parameters in evaluating biological behaviour and prognosis of lung cancer; it will be of benefit to clinical treatment and prognostic evaluation.

  20. 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.

  1. Strong Expression of Hypoxia-Inducible Factor-1α (HIF-1α Is Associated with Axl Expression and Features of Aggressive Tumors in African Breast Cancer.

    Directory of Open Access Journals (Sweden)

    Hawa Nalwoga

    Full Text Available Inhibition of hypoxia-inducible factor (HIF and Axl receptor tyrosine kinase is being evaluated for targeted therapy in solid tumors. Both HIF-1α and Axl influence tumor growth and metastatic potential, and they have been linked to treatment failure in many cancers. However, there is a lack of reports on HIF-1α expression in African breast cancer, which has a poor prognosis, and novel treatment targets must therefore be established. Here, we aimed to evaluate HIF-1α in relation to Axl expression, angiogenesis markers, and other tumor characteristics in a series of African breast cancer.Using immunohistochemistry, we examined 261 invasive breast cancers on tissue microarrays for HIF-1α and Axl as well as several other markers, and a subset of 185 cases had information on VEGF (vascular endothelial growth factor expression, microvessel density (MVD, proliferating microvessel density (pMVD and vascular proliferation index (VPI for important comparisons.Strong HIF-1α expression was associated with increased Axl (p = 0.007, VEGF (p<0.0005, and p53 (p = 0.032 expression, as well as high tumor cell proliferation by Ki-67 (p = 0.006, and high tumor grade (p = 0.003. Tumors with strong HIF-1α expression had significantly higher MVD (p = 0.019 and higher pMVD (p = 0.027 than tumors with weak expression.High HIF-1α expression is significantly associated with Axl and VEGF expression, and with markers of poor prognosis in this series of breast cancer, suggesting HIF-1α and Axl as potential therapeutic targets in African breast cancer.

  2. Inhibition of hypoxia-inducible factor (HIF) hydroxylases by citric acid cycle intermediates: possible links between cell metabolism and stabilization of HIF.

    Science.gov (United States)

    Koivunen, Peppi; Hirsilä, Maija; Remes, Anne M; Hassinen, Ilmo E; Kivirikko, Kari I; Myllyharju, Johanna

    2007-02-16

    The stability and transcriptional activity of the hypoxia-inducible factors (HIFs) are regulated by two oxygen-dependent events that are catalyzed by three HIF prolyl 4-hydroxylases (HIF-P4Hs) and one HIF asparaginyl hydroxylase (FIH). We have studied possible links between metabolic pathways and HIF hydroxylases by analyzing the abilities of citric acid cycle intermediates to inhibit purified human HIF-P4Hs and FIH. Fumarate and succinate were identified as in vitro inhibitors of all three HIF-P4Hs, fumarate having K(i) values of 50-80 microM and succinate 350-460 microM, whereas neither inhibited FIH. Oxaloacetate was an additional inhibitor of all three HIF-P4Hs with K(i) values of 400-1000 microM and citrate of HIF-P4H-3, citrate being the most effective inhibitor of FIH with a K(i) of 110 microM. Culturing of cells with fumarate diethyl or dimethyl ester, or a high concentration of monoethyl ester, stabilized HIF-1alpha and increased production of vascular endothelial growth factor and erythropoietin. Similar, although much smaller, changes were found in cultured fibroblasts from a patient with fumarate hydratase (FH) deficiency and upon silencing FH using small interfering RNA. No such effects were seen upon culturing of cells with succinate diethyl or dimethyl ester. As FIH was not inhibited by fumarate, our data indicate that the transcriptional activity of HIF is quite high even when binding of the coactivator p300 is prevented. Our data also support recent suggestions that the increased fumarate and succinate levels present in the FH and succinate dehydrogenase-deficient tumors, respectively, can inhibit the HIF-P4Hs with consequent stabilization of HIF-alphas and effects on tumor pathology.

  3. Hypoxia induces heart regeneration in adult mice.

    Science.gov (United States)

    Nakada, Yuji; Canseco, Diana C; Thet, SuWannee; Abdisalaam, Salim; Asaithamby, Aroumougame; Santos, Celio X; Shah, Ajay M; Zhang, Hua; Faber, James E; Kinter, Michael T; Szweda, Luke I; Xing, Chao; Hu, Zeping; Deberardinis, Ralph J; Schiattarella, Gabriele; Hill, Joseph A; Oz, Orhan; Lu, Zhigang; Zhang, Cheng Cheng; Kimura, Wataru; Sadek, Hesham A

    2017-01-12

    The adult mammalian heart is incapable of regeneration following cardiomyocyte loss, which underpins the lasting and severe effects of cardiomyopathy. Recently, it has become clear that the mammalian heart is not a post-mitotic organ. For example, the neonatal heart is capable of regenerating lost myocardium, and the adult heart is capable of modest self-renewal. In both of these scenarios, cardiomyocyte renewal occurs via the proliferation of pre-existing cardiomyocytes, and is regulated by aerobic-respiration-mediated oxidative DNA damage. Therefore, we reasoned that inhibiting aerobic respiration by inducing systemic hypoxaemia would alleviate oxidative DNA damage, thereby inducing cardiomyocyte proliferation in adult mammals. Here we report that, in mice, gradual exposure to severe systemic hypoxaemia, in which inspired oxygen is gradually decreased by 1% and maintained at 7% for 2 weeks, results in inhibition of oxidative metabolism, decreased reactive oxygen species production and oxidative DNA damage, and reactivation of cardiomyocyte mitosis. Notably, we find that exposure to hypoxaemia 1 week after induction of myocardial infarction induces a robust regenerative response with decreased myocardial fibrosis and improvement of left ventricular systolic function. Genetic fate-mapping analysis confirms that the newly formed myocardium is derived from pre-existing cardiomyocytes. These results demonstrate that the endogenous regenerative properties of the adult mammalian heart can be reactivated by exposure to gradual systemic hypoxaemia, and highlight the potential therapeutic role of hypoxia in regenerative medicine.

  4. Participation of the PI-3K/Akt-NF-κB signaling pathways in hypoxia-induced mitogenic factor-stimulated Flk-1 expression in endothelial cells

    Directory of Open Access Journals (Sweden)

    Huang Chuanshu

    2006-07-01

    Full Text Available Abstract Background Hypoxia-induced mitogenic factor (HIMF, a lung-specific growth factor, promotes vascular tubule formation in a matrigel plug model. We initially found that HIMF enhances vascular endothelial growth factor (VEGF expression in lung epithelial cells. In present work, we tested whether HIMF modulates expression of fetal liver kinase-1 (Flk-1 in endothelial cells, and dissected the possible signaling pathways that link HIMF to Flk-1 upregulation. Methods Recombinant HIMF protein was intratracheally instilled into adult mouse lungs, Flk-1 expression was examined by immunohistochemistry and Western blot. The promoter-luciferase reporter assay and real-time RT-PCR were performed to examine the effects of HIMF on Flk-1 expression in mouse endothelial cell line SVEC 4–10. The activation of NF-kappa B (NF-κB and phosphorylation of Akt, IKK, and IκBα were examined by luciferase assay and Western blot, respectively. Results Intratracheal instillation of HIMF protein resulted in a significant increase of Flk-1 production in lung tissues. Stimulation of SVEC 4–10 cells by HIMF resulted in increased phosphorylation of IKK and IκBα, leading to activation of NF-κB. Blocking NF-κB signaling pathway by dominant-negative mutants of IKK and IκBα suppressed HIMF-induced Flk-1 upregulation. Mutation or deletion of NF-κB binding site within Flk-1 promoter also abolished HIMF-induced Flk-1 expression in SVEC 4–10 cells. Furthermore, HIMF strongly induced phosphorylation of Akt. A dominant-negative mutant of PI-3K, Δp85, as well as PI-3K inhibitor LY294002, blocked HIMF-induced NF-κB activation and attenuated Flk-1 production. Conclusion These results suggest that HIMF upregulates Flk-1 expression in endothelial cells in a PI-3K/Akt-NF-κB signaling pathway-dependent manner, and may play critical roles in pulmonary angiogenesis.

  5. Overexpression of hypoxia-inducible factor 1 alpha impacts FoxP3 levels in mycosis fungoides--cutaneous T-cell lymphoma: clinical implications.

    Science.gov (United States)

    Alcántara-Hernández, M; Torres-Zárate, C; Pérez-Montesinos, G; Jurado-Santacruz, F; Domínguez-Gómez, M A; Peniche-Castellanos, A; Ferat-Osorio, E; Neri, N; Nambo, M J; Alvarado-Cabrero, I; Moreno-Lafont, M; Huerta-Yepez, S; Bonifaz, L C

    2014-05-01

    Mycosis fungoides (MF) is the most common variant of primary cutaneous T-cell lymphoma, and decreased forkhead box P3 (FoxP3) expression has been reported in MF late stages. Hypoxia-inducible factor 1 alpha (HIF-1α) may regulate FoxP3 expression; however, it is unknown whether HIF-1α is expressed in the CD4(+) T cells of MF patients and how it could affect the expression of FoxP3. Therefore, we evaluated the expression of HIF-1α and FoxP3 in CD4(+) T cells obtained from the skin lesions of MF patients. We found increased cell proliferation and an increase in CD4(+) T cells with an aberrant phenotype among early stage MF patients. HIF-1α was overexpressed in these CD4(+) T cells. In addition, we found a decrease in the percentage of FoxP3(+) cells both in the skin of MF patients, when compared with control skin samples, and with disease progression. In addition, a negative correlation was established between HIF-1α and FoxP3 expression. Skin HIF-1α expression in MF patients correlated with the extent of the affected area and increased with the disease progression. Finally, we showed that ex vivo inhibition of HIF-1α degradation increases the percentage of FoxP3(+) T cells in skin lesions. Our results suggest that overexpression of HIF-1α affects the levels of FoxP3 in MF patients, which could have relevant implications in terms of disease outcome.

  6. Pilot trial of EZN-2968, an antisense oligonucleotide inhibitor of hypoxia-inducible factor-1 alpha (HIF-1α), in patients with refractory solid tumors.

    Science.gov (United States)

    Jeong, Woondong; Rapisarda, Annamaria; Park, Sook Ryun; Kinders, Robert J; Chen, Alice; Melillo, Giovanni; Turkbey, Baris; Steinberg, Seth M; Choyke, Peter; Doroshow, James H; Kummar, Shivaani

    2014-02-01

    Hypoxia-inducible factor-1 (HIF-1) facilitates the adaptation of normal and tumor tissues to oxygen deprivation. HIF-1 is frequently overexpressed in cancer cells, where it is involved in the upregulation of many genes necessary for survival. EZN-2968 is an antisense oligodeoxynucleotide that specifically targets HIF-1α, one of the subunits of HIF-1. We conducted a trial of EZN-2968 in patients with refractory solid tumors to evaluate antitumor response and to measure modulation of HIF-1α mRNA and protein levels as well as HIF-1 target genes. Adult patients with refractory advanced solid tumors were administered EZN-2968 as a 2-h IV infusion at a dose of 18 mg/kg once a week for three consecutive weeks followed by 3-week off; in a 6-week cycle. Tumor biopsies and dynamic contrast enhanced MRI (DCE-MRI) were performed at baseline and after the third dose. Ten patients were enrolled, of whom all were evaluable for response; one patient with a duodenal neuroendocrine tumor had prolonged stabilization of disease (24 weeks). Reduction in HIF-1α mRNA levels compared to baseline was demonstrated in 4 of 6 patients with paired tumor biopsies. Reductions in levels of HIF-1α protein and mRNA levels of some target genes were observed in two patients. Quantitative analysis of DCE-MRI from two patients revealed changes in K (trans) and k ep. The trial was closed prematurely when the sponsor suspended development of this agent. This trial provides preliminary proof of concept for modulation of HIF-1α mRNA and protein expression and target genes in tumor biopsies following the administration of EZN-2968.

  7. Prognostic implications of epithelial to mesenchymal transition related proteins (E-cadherin, Snail) and hypoxia inducible factor 1α in endometrioid endometrial carcinoma.

    Science.gov (United States)

    Abouhashem, Nehal S; Ibrahim, Doaa Abdelaziz; Mohamed, Abdel Motaleb

    2016-06-01

    The epithelial-mesenchymal transition (EMT) is an important step in the invasion and metastasis of cancer. E-cadherin downregulation, which is essentially controlled by EMT-mediated proteins such as Snail, is a main molecular feature of this process. Tumor hypoxia is one of the essential biological phenomena that are associated with the development and progression of various solid tumors. Recently, hypoxia and hypoxia-inducible factor 1α (HIF-1α) signaling pathway were identified to have an essential role in the regulation of EMT phenotype. The aim of the study was to evaluate the prognostic impact of EMT-related proteins (E-cadherin, Snail) and HIF-1α in endometrioid endometrial carcinoma (EEC) among Egyptian women. Immunohistochemical evaluation of E-cadherin, Snail, and HIF-1α expression was performed using 50 cases of EEC. The relationship between protein expression and clinicopathological features was investigated. The frequency of immunopositivity for E-cadherin, Snail, and HIF-1α in our cases of EEC was 82%, 28%, and 66%, respectively. Reduced E-cadherin and increased nuclear expression of Snail as well as HIF-1α were significantly associated with histopathologic grade, clinical stage myometrial invasion, and lymph node involvement. Statistical analysis showed a positive correlation between HIF-1α overexpression and Snail upregulation (τ= +0.252, P= .025); however, E-cadherin expression level was inversely correlated with enhanced Snail expression (τ= -0.450, PSnail immunoreactivity and positively related to E-cadherin expression. E-cadherin and Snail have a predictive value in EEC. In conclusion, the current study reveals that both Snail and HIF-1α expressions are significantly associated with poor prognosis in EEC; however, E-cadherin expression is considered a marker of good prognosis. E-cadherin and Snail expression has a predictive value in EEC management. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Regulation of glut1 mRNA by hypoxia-inducible factor-1. Interaction between H-ras and hypoxia

    National Research Council Canada - National Science Library

    Chen, C; Pore, N; Behrooz, A; Ismail-Beigi, F; Maity, A

    2001-01-01

    Oncogenic transformation and hypoxia both induce glut1 mRNA. We studied the interaction between the ras oncogene and hypoxia in up-regulating glut1 mRNA levels using Rat1 fibroblasts transformed with H-ras (Rat1-ras...

  9. Over-expression of hypoxia-inducible factor 1 alpha increases angiogenesis of LNCaP cells

    Institute of Scientific and Technical Information of China (English)

    Yili Han; Dalin He; Yong Luo; Hepeng Cheng; Guangfeng Zhu

    2007-01-01

    Objective:To evaluate the effect of HIF-1 α over-expression on angiogenesis in human prostate cancer cells. Methods:LNCaP cells(a human prostate cancer cell line) were transfected with the recombinant plasmid pcDNA3.1(-)-HIF-1α with Lipofectamine 2000 system. The positive clones were selected by G418 being further confirmed by Western blot and immunofluorescence. The expression levels of VEGF, iNOS and Ang- Ⅱ were determined. Results:The expression of HIF-1α in the LNCaP/HIF1α cells was significantly increased in transfected cells, which induced the up-regulation of VEGF, iNOS, whereas Ang- Ⅱ expression remained un- changed. Conclusion :Over-expression of HIF-1α can induce angiogenesis proteins and may improve the angiogenesis potency of prostate cancer.

  10. 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

  11. Hypoxia inducible factor-1-alpha (HIF-1α) is related to both angiogenesis and inflammation in rheumatoid arthritis

    NARCIS (Netherlands)

    Brouwer, Elisabeth; Gouw, Annette S.H.; Posthumus, Marcel D.; Van Leeuwen, Miek A.; Boerboom, Alexander L.; Bijzet, Johan; Bos, Reinhard; Limburg, Piet C.; Kallenberg, Cees G.M.; Westra, Johanna

    2009-01-01

    Objectives: Despite the important role of the transcription factor HIF-1α in angiogenesis and inflammation, only a few studies on HIF-1α expression have been performed in RA patients. The aim of the present study was to identify the layer in synovial tissue of RA patients where HIF1α is expressed an

  12. Hypoxia inducible factor-1-alpha (HIF-1 alpha) is related to both angiogenesis and inflammation in rheumatoid arthritis

    NARCIS (Netherlands)

    Brouwer, E.; Gouw, A. S. H.; Posthumus, M. D.; van Leeuwen, M. A.; Boerboom, A. L.; Bijzet, J.; Limburg, P. C.; Kallenberg, C. G. M.; Westra, J.; Bos, R

    2009-01-01

    Objectives Despite the important role of the transcription factor HIF-1 alpha in angiogenesis and inflammation, only a few studies on HIF-1 alpha expression have been performed in RA patients. The aim of the present study was to identify the layer in synovial tissue of RA patients where HIF1 alpha i

  13. Methylation impact analysis of erythropoietin (EPO) Gene to hypoxia inducible factor-1α (HIF-1α) activity.

    Science.gov (United States)

    Dewi, Firli Rahmah Primula; Fatchiyah, Fatchiyah

    2013-01-01

    Erythropoietin (EPO) is a glycoprotein hormone that play a role as key regulator in the production of red blood cells. The promoter region of EPO is methylated in normoxic (non-hypoxia) condition, but not in hypoxic condition. Methylation of the EPO enhancer region decline the transcription activity of EPO gene. The aim of this study is to investigate how different methylation percentage affected on the regulation and transcriptional activity of EPO gene. The DNA sequence of erythropoietin gene and protein sequence was retrieved from the sequence database of NCBI. DNA structure was constructed using 3D-DART web server and modeling structure of HIF1 predicted using SWISS-MODEL web server. Methylated DNA sequence of EPO gene using performed with YASARA View software and docking of EPO gene and transcription factor HIF1 analyzed by using HADDOCK webserver. Our result showed that binding energy in 46% methylated DNA was higher (-161,45 kcal/mol) than in unmethylated DNA (-194,16 kcal/mol) and 8% methylated DNA (-175,94 kcal/mol). So, we presume that a silencing mechanism of the Epo gene by methylation is correlated with the binding energy, which is required for interaction. A higher methylation percentage correlates with a higher binding energy which can cause an unstable interaction between DNA and transcription factor. In conclution, methylation of promoter and enhancer region of Epo gene leads to silencing.

  14. Successful tumour necrosis factor (TNF) blocking therapy suppresses oxidative stress and hypoxia-induced mitochondrial mutagenesis in inflammatory arthritis

    LENUS (Irish Health Repository)

    Biniecka, Monika

    2011-07-25

    Abstract Introduction To examine the effects of tumour necrosis factor (TNF) blocking therapy on the levels of early mitochondrial genome alterations and oxidative stress. Methods Eighteen inflammatory arthritis patients underwent synovial tissue oxygen (tpO2) measurements and clinical assessment of disease activity (DAS28-CRP) at baseline (T0) and three months (T3) after starting biologic therapy. Synovial tissue lipid peroxidation (4-HNE), T and B cell specific markers and synovial vascular endothelial growth factor (VEGF) were quantified by immunohistochemistry. Synovial levels of random mitochondrial DNA (mtDNA) mutations were assessed using Random Mutation Capture (RMC) assay. Results 4-HNE levels pre\\/post anti TNF-α therapy were inversely correlated with in vivo tpO2 (P < 0.008; r = -0.60). Biologic therapy responders showed a significantly reduced 4-HNE expression (P < 0.05). High 4-HNE expression correlated with high DAS28-CRP (P = 0.02; r = 0.53), tender joint count for 28 joints (TJC-28) (P = 0.03; r = 0.49), swollen joint count for 28 joints (SJC-28) (P = 0.03; r = 0.50) and visual analogue scale (VAS) (P = 0.04; r = 0.48). Strong positive association was found between the number of 4-HNE positive cells and CD4+ cells (P = 0.04; r = 0.60), CD8+ cells (P = 0.001; r = 0.70), CD20+ cells (P = 0.04; r = 0.68), CD68+ cells (P = 0.04; r = 0.47) and synovial VEGF expression (P = 0.01; r = 063). In patients whose in vivo tpO2 levels improved post treatment, significant reduction in mtDNA mutations and DAS28-CRP was observed (P < 0.05). In contrast in those patients whose tpO2 levels remained the same or reduced at T3, no significant changes for mtDNA mutations and DAS28-CRP were found. Conclusions High levels of synovial oxidative stress and mitochondrial mutation burden are strongly associated with low in vivo oxygen tension and synovial inflammation. Furthermore these significant mitochondrial genome alterations are rescued following successful anti TNF

  15. Altered Level of Soluble fms-like Tyrosine Kinase 1 (sFlt1 and Hypoxia Inducible Factor-1alpha (HIF-1alpha in Normotensive Pregnancy and Preeclampsia

    Directory of Open Access Journals (Sweden)

    John Wantania

    2013-08-01

    Full Text Available BACKGROUND: Preeclampsia is still a significant problem worldwide. Of the many suggested mechanisms of its pathogenesis, the latest one is the balance of angiogenic factor and its relationship with hypoxia factors. The objective of this study was to observe changes or dynamic process of soluble fms-like tyrosine kinase 1 (sFlt1 as anti-angiogenic factor and hypoxia inducible factor 1-alpha (HIF-1α as hypoxia marker in normotensive pregnancy and preeclampsia in mid-term and full-term pregnancies. METHODS: A cohort study was conducted on 36 normotensive subjects, first examination was conducted at 20-28 weeks of gestation. Then second examination was conducted at the time of preeclampsia diagnosed or full-term pregnancy. Preeclampsia was characterized by hypertension of systolic blood pressure ≥140 mmHg, diastolic blood pressure ≥90 mmHg, with two readings separated in 4-6 hours period, and/or proteinuria with urine dipstick of ≥1+ or ≥300 mg per 24 hours. Examinations of sFlt-1 and HIF-1α were done by enzyme-linked immunosorbent assay method. Statistical analysis was done using a significance level of p<0.05. RESULTS: Concentration of sFlt-1 was elevated in normotensive pregnancy and preeclampsia. Higher sFlt-1 concentration elevation was seen in preeclamptic group comparing to normotensive group, although not significant. This finding was related to the fact that investigated subjects were mostly developing mild preeclampsia merely. Comparing to normotensive group, preeclamptic group had higher HIF-1α concentration-per-week elevation, but not significant. There was a positive correlation between concentrations of sFlt-1 and HIF-1α, but not significant. CONCLUSIONS: sFlt-1 concentration elevation was correlated with preeclampsia. Therefore comparing to averages, changes of sFlt-1 concentrations were more important. Concentrations of HIF-1α and sFlt-1 were positively correlated. KEYWORDS: sFlt-1, HIF-1α, preeclampsia, normotension.

  16. The novel hypoxic cytotoxin, TX-2098 has antitumor effect in pancreatic cancer; possible mechanism through inhibiting VEGF and hypoxia inducible factor-1{alpha} targeted gene expression

    Energy Technology Data Exchange (ETDEWEB)

    Miyake, Kotaro, E-mail: hif.panc@gmail.com [Department of Surgery, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503 (Japan); Nishioka, Masanori; Imura, Satoru; Batmunkh, Erdenebulgan [Department of Surgery, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503 (Japan); Uto, Yoshihiro [Department of Biological Science and Technology, Institute of Socio Technosciences, The University of Tokushima Graduate School, Tokushima 770-8503 (Japan); Nagasawa, Hideko [Laboratory of Pharmaceutical and Medicinal Chemistry, Gifu Pharmaceutical University, Gifu 501-1196 (Japan); Hori, Hitoshi [Department of Biological Science and Technology, Institute of Socio Technosciences, The University of Tokushima Graduate School, Tokushima 770-8503 (Japan); Shimada, Mitsuo [Department of Surgery, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503 (Japan)

    2012-08-01

    Tumor hypoxia has been considered to be a potential therapeutic target, because hypoxia is a common feature of solid tumors and is associated with their malignant phenotype. In the present study, we investigated the antitumor effect of a novel hypoxic cytotoxin, 3-[2-hydroxyethyl(methyl)amino]-2-quinoxalinecarbonitrile 1,4-dioxide (TX-2098) in inhibiting the expression of hypoxia inducible factor-1{alpha} (HIF-1{alpha}), and consequently vascular endothelial cell growth factor (VEGF) expression in pancreatic cancer. The antitumor effects of TX-2098 under hypoxia were tested against various human pancreatic cancer cell lines using WST-8 assay. VEGF protein induced pancreatic cancer was determined on cell-free supernatant by ELISA. Moreover, nude mice bearing subcutaneously (s.c.) or orthotopically implanted human SUIT-2 were treated with TX-2098. Tumor volume, survival and expression of HIF-1 and associated molecules were evaluated in treatment versus control groups. In vitro, TX-2098 inhibited the proliferation of various pancreatic cancer cell lines. In s.c model, tumors from nude mice injected with pancreatic cancer cells and treated with TX-2098 showed significant reductions in volume (P < 0.01 versus control). Quantitative real-time reverse transcription-PCR analysis revealed that TX-2098 significantly inhibited mRNA expression of the HIF-1 associated molecules, VEGF, glucose transporter 1 and Aldolase A (P < 0.01 versus control). These treatments also prolong the survival in orthotopic models. These results suggest that the effect of TX-2098 in pancreatic cancer might be correlated with the expression of VEGF and HIF-1 targeted molecules. -- Highlights: Black-Right-Pointing-Pointer We designed and synthesized novel hypoxic cytoxin, TX-2098. Black-Right-Pointing-Pointer TX-2098 inhibited the proliferation of human pancreatic cancer cells than TPZ. Black-Right-Pointing-Pointer TX-2098 reduced VEGF protein level than TPZ. Black-Right-Pointing-Pointer TX-2098

  17. Putative role of ischemic postconditioning in a rat model of limb ischemia and reperfusion: involvement of hypoxia-inducible factor-1? expression

    Directory of Open Access Journals (Sweden)

    T. Wang

    2014-09-01

    Full Text Available Hypoxia-inducible factor-1α (HIF-1α is one of the most potent angiogenic growth factors. It improves angiogenesis and tissue perfusion in ischemic skeletal muscle. In the present study, we tested the hypothesis that ischemic postconditioning is effective for salvaging ischemic skeletal muscle resulting from limb ischemia-reperfusion injury, and that the mechanism involves expression of HIF-1α. Wistar rats were randomly divided into three groups (n=36 each: sham-operated (group S, hindlimb ischemia-reperfusion (group IR, and ischemic postconditioning (group IPO. Each group was divided into subgroups (n=6 according to reperfusion time: immediate (0 h, T0, 1 h (T1, 3 h (T3, 6 h (T6, 12 h (T12, and 24 h (T24. In the IPO group, three cycles of 30-s reperfusion and 30-s femoral aortic reocclusion were carried out before reperfusion. At all reperfusion times (T0-T24, serum creatine kinase (CK and lactate dehydrogenase (LDH activities, as well as interleukin (IL-6, IL-10, and tumor necrosis factor-α (TNF-α concentrations, were measured in rats after they were killed. Histological and immunohistochemical methods were used to assess the skeletal muscle damage and HIF-1α expression in skeletal muscle ischemia. In groups IR and IPO, serum LDH and CK activities and TNF-α, IL-6, and IL-10 concentrations were all significantly increased compared to group S, and HIF-1α expression was up-regulated (P<0.05 or P<0.01. In group IPO, serum LDH and CK activities and TNF-α and IL-6 concentrations were significantly decreased, IL-10 concentration was increased, HlF-1α expression was down-regulated (P<0.05 or P<0.01, and the pathological changes were reduced compared to group IR. The present study suggests that ischemic postconditioning can reduce skeletal muscle damage caused by limb ischemia-reperfusion and that its mechanisms may be related to the involvement of HlF-1α in the limb ischemia-reperfusion injury-triggered inflammatory response.

  18. Putative role of ischemic postconditioning in a rat model of limb ischemia and reperfusion: involvement of hypoxia-inducible factor-1α expression

    Energy Technology Data Exchange (ETDEWEB)

    Wang, T. [Department of Anesthesiology, Shuyang People' s Hospital, JiangSu (China); Zhou, Y.T. [Department of General Surgery, Shuyang People' s Hospital, JiangSu (China); Chen, X.N. [Institute of Pathophysiology, School of Basic Medical Sciences, LanZhou University, Lanzhou, Gansu (China); Zhu, A.X. [Department of Pharmacy, Shuyang People' s Hospital, JiangSu (China)

    2014-07-25

    Hypoxia-inducible factor-1α (HIF-1α) is one of the most potent angiogenic growth factors. It improves angiogenesis and tissue perfusion in ischemic skeletal muscle. In the present study, we tested the hypothesis that ischemic postconditioning is effective for salvaging ischemic skeletal muscle resulting from limb ischemia-reperfusion injury, and that the mechanism involves expression of HIF-1α. Wistar rats were randomly divided into three groups (n=36 each): sham-operated (group S), hindlimb ischemia-reperfusion (group IR), and ischemic postconditioning (group IPO). Each group was divided into subgroups (n=6) according to reperfusion time: immediate (0 h, T{sub 0}), 1 h (T{sub 1}), 3 h (T{sub 3}), 6 h (T{sub 6}), 12 h (T{sub 12}), and 24 h (T{sub 24}). In the IPO group, three cycles of 30-s reperfusion and 30-s femoral aortic reocclusion were carried out before reperfusion. At all reperfusion times (T{sub 0}-T{sub 24}), serum creatine kinase (CK) and lactate dehydrogenase (LDH) activities, as well as interleukin (IL)-6, IL-10, and tumor necrosis factor-α (TNF-α) concentrations, were measured in rats after they were killed. Histological and immunohistochemical methods were used to assess the skeletal muscle damage and HIF-1α expression in skeletal muscle ischemia. In groups IR and IPO, serum LDH and CK activities and TNF-α, IL-6, and IL-10 concentrations were all significantly increased compared to group S, and HIF-1α expression was up-regulated (P<0.05 or P<0.01). In group IPO, serum LDH and CK activities and TNF-α and IL-6 concentrations were significantly decreased, IL-10 concentration was increased, HlF-1α expression was down-regulated (P<0.05 or P<0.01), and the pathological changes were reduced compared to group IR. The present study suggests that ischemic postconditioning can reduce skeletal muscle damage caused by limb ischemia-reperfusion and that its mechanisms may be related to the involvement of HlF-1α in the limb ischemia-reperfusion injury

  19. The role of hypoxia inducible factor-1α in the increased MMP-2 and MMP-9 production by human monocytes exposed to nickel nanoparticles

    Science.gov (United States)

    WAN, RONG; MO, YIQUN; CHIEN, SUFAN; LI, YIHUA; LI, YIXIN; TOLLERUD, DAVID J.; ZHANG, QUNWEI

    2016-01-01

    Nickel is an important economic commodity, but it can cause skin sensitization and may cause lung diseases such as lung fibrosis, pneumonitis, bronchial asthma and lung cancer. With development of nanotechnology, nano-sized nickel (Nano-Ni) and nano-sized titanium dioxide (Nano-TiO2) particles have been developed and produced for many years with new formulations and surface properties to meet novel demands. Our previous studies have shown that Nano-Ni instilled into rat lungs caused a greater inflammatory response as compared with standard-sized nickel (5 μm) at equivalent mass concentrations. Nano-Ni caused a persistent high level of inflammation in lungs even at low doses. Recently, several studies have shown that nanoparticles can translocate from the lungs to the circulatory system. To evaluate the potential systemic effects of metal nanoparticles, we compared the effects of Nano-Ni and Nano-TiO2 on matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) gene expression and activity. Our results showed that exposure of human monocyte U937 to Nano-Ni caused dose- and time- dependent increase in MMP-2 and MMP-9 mRNA expression and pro-MMP-2 and pro-MMP-9 activity, but Nano-TiO2 did not. Nano-Ni also caused dose- and time- related increase in tissue inhibitor of metalloproteinases 1 (TIMP-1), but Nano-TiO2 did not. To determine the potential mechanisms involved, we measured the expression of hypoxia inducible factor 1α (HIF-1α) in U937 cells exposed to Nano-Ni and Nano-TiO2. Our results showed that exposure to Nano-Ni caused HIF-1α accumulation in the nucleus. Furthermore, pre-treatment of U937 cells with heat shock protein 90 (Hsp90) inhibitor, 17-(Allylamino)-17-demethoxygeldanamycin (17-AAG), prior to exposure to Nano-Ni significantly abolished Nano-Ni-induced MMP-2 and MMP-9 mRNA upregulation and increased pro-MMP-2 and pro-MMP-9 activity. Our results suggest that HIF-1α accumulation may be involved in the increased MMP-2 and MMP-9 production in U937 cells

  20. Cloning and characterization of hypoxia-inducible factor-1 subunits from Ascaris suum - a parasitic nematode highly adapted to changes of oxygen conditions during its life cycle.

    Science.gov (United States)

    Goto, Miho; Amino, Hisako; Nakajima, Mikage; Tsuji, Naotoshi; Sakamoto, Kimitoshi; Kita, Kiyoshi

    2013-03-01

    The parasitic nematode Ascaris suum successfully adapts to a significant decrease in oxygen availability during its life cycle by altering its metabolic system dramatically. However, little is known about the regulatory mechanisms of adaptation to hypoxic environments in A. suum. In multicellular organisms, hypoxia-inducible factor-1 (HIF-1), a heterodimeric transcription factor composed of HIF-1α and HIF-1β subunits, is a master regulator of genes involved in adaptation to hypoxia. In the present study, cDNAs encoding HIF-1α and HIF-1β were cloned from A. suum and characterized. The full-length A. suum hif-1α and hif-1β cDNAs contain open reading frames encoding proteins with 832 and 436 amino acids, respectively. In the deduced amino acid sequences of A. suum HIF-1α and HIF-1β, functional domains essential for DNA-binding, dimerization, and oxygen-dependent prolyl hydroxylation were conserved. The interaction between A. suum HIF-1α and HIF-1β was confirmed by the yeast two-hybrid assay. Both A. suum hif-1α and hif-1β mRNAs were expressed at all stages examined (fertilized eggs, third-stage larvae, lung-stage larvae, young adult worms, and adult muscle tissue), and most abundantly in the aerobic free-living third-stage larvae, followed by a gradual decrease after infection of the host. hif-1 mRNA transcription was not sensitive to the oxygen environment in either third-stage larvae or adult worms (muscle tissue), and was regulated in a stage-specific manner. High expression of hif-1 mRNAs in third-stage larvae suggests its contribution to pre-adaptation to a hypoxic environment after infection of their host. Sequence analysis of 5'-upstream regions of mitochondrial complex II (succinate-ubiquinone reductase/quinol-fumarate reductase) genes, which show stage-specific expression and play an important role in oxygen adaptation during the life cycle, revealed that all subunits except for the adult-type flavoprotein subunit (Fp) possess putative hypoxia

  1. Transarterial embolization combined with RNA interference targeting hypoxia-inducible factor-1α for hepatocellular carcinoma: a preliminary study of rat model.

    Science.gov (United States)

    Ni, Jia-Yan; Xu, Lin-Feng; Wang, Wei-Dong; Huang, Qiao-Sheng; Sun, Hong-Liang; Chen, Yao-Ting

    2017-02-01

    To study whether transarterial embolization (TAE) with RNA interference (RNAi) targeting hypoxia-inducible factor-1α (HIF-1α) can improve efficacy of TAE in treating hepatocellular carcinoma (HCC). CBRH-7919 rat hepatoma cell line was used and HCC models of rats were constructed. The siRNA transfection compound was made by mixing specific siRNA and Lipofectamine 2000™. Delivery and transfection of siRNA were administered by injecting iodized oil emulsion (diluted lipiodol and siRNA) via hepatic artery. The expression levels of mRNA and protein were detected using the real-time reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry and western blotting assays, respectively. In vitro experiment, the specific HIF-1α-siRNA was proved to inhibit expression levels of HIF-1α and vascular endothelial growth factor (VEGF) effectively. In animal study, real-time RT-PCR assay showed the average relative mRNA expressions of HIF-1α were 0.31 ± 0.01, 0.65 ± 0.03, 0.46 ± 0.005, and 1.00 ± 0.00 in TAE + siRNA, siRNA, TAE, and control groups, respectively. Western blotting assay showed the average relative protein expressions of HIF-1α were 0.13 ± 0.02, 0.87 ± 0.02, 0.39 ± 0.02, and 1.02 ± 0.01 in TAE + siRNA, siRNA, TAE, and control groups, respectively. Compared with control, TAE, and siRNA groups, TAE + siRNA can significantly inhibit protein expressions of HIF-1α and VEGF (P HIF-1α < 0.001; P VEGF < 0.001). Overall survival of rats underwent TAE + siRNA was significantly longer than that of rats treated with TAE monotherapy (P = 0.001). This animal study showed TAE combined with HIF-1α-RNAi could significantly improve efficacy of TAE in treating HCC by inhibiting expressions of HIF-1α and VEGF after TAE treatment.

  2. Absence of the Birt-Hogg-Dubé gene product is associated with increased hypoxia-inducible factor transcriptional activity and a loss of metabolic flexibility.

    Science.gov (United States)

    Preston, R S; Philp, A; Claessens, T; Gijezen, L; Dydensborg, A B; Dunlop, E A; Harper, K T; Brinkhuizen, T; Menko, F H; Davies, D M; Land, S C; Pause, A; Baar, K; van Steensel, M A M; Tee, A R

    2011-03-10

    Under conditions of reduced tissue oxygenation, hypoxia-inducible factor (HIF) controls many processes, including angiogenesis and cellular metabolism, and also influences cell proliferation and survival decisions. HIF is centrally involved in tumour growth in inherited diseases that give rise to renal cell carcinoma (RCC), such as Von Hippel-Lindau syndrome and tuberous sclerosis complex. In this study, we examined whether HIF is involved in tumour formation of RCC in Birt-Hogg-Dubé syndrome. For this, we analysed a Birt-Hogg-Dubé patient-derived renal tumour cell line (UOK257) that is devoid of the Birt-Hogg-Dubé protein (BHD) and observed high levels of HIF activity. Knockdown of BHD expression also caused a threefold activation of HIF, which was not as a consequence of more HIF1α or HIF2α protein. Transcription of HIF target genes VEGF, BNIP3 and CCND1 was also increased. We found nuclear localization of HIF1α and increased expression of VEGF, BNIP3 and GLUT1 in a chromophobe carcinoma from a Birt-Hogg-Dubé patient. Our data also reveal that UOK257 cells have high lactate dehydrogenase, pyruvate kinase and 3-hydroxyacyl-CoA dehydrogenase activity. We observed increased expression of pyruvate dehydrogenase kinase 1 (a HIF gene target), which in turn leads to increased phosphorylation and inhibition of pyruvate dehydrogenase. Together with increased protein levels of GLUT1, our data reveal that UOK257 cells favour glycolytic rather than lipid metabolism (a cancer phenomenon termed the 'Warburg effect'). UOK257 cells also possessed a higher expression level of the L-lactate influx monocarboxylate transporter 1 and consequently utilized L-lactate as a metabolic fuel. As a result of their higher dependency on glycolysis, we were able to selectively inhibit the growth of these UOK257 cells by treatment with 2-deoxyglucose. This work suggests that targeting glycolytic metabolism may be used therapeutically to treat Birt-Hogg-Dubé-associated renal lesions.

  3. Prognostic Significance of Hypoxia-Inducible Factor Expression in Renal Cell Carcinoma: A PRISMA-compliant Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Fan, Yang; Li, Hongzhao; Ma, Xin; Gao, Yu; Chen, Luyao; Li, Xintao; Bao, Xu; Du, Qingshan; Zhang, Yu; Zhang, Xu

    2015-09-01

    The prognostic value of hypoxia-inducible factor (HIF) in renal cell carcinoma (RCC) has been evaluated in a large number of studies, but the reports were inconsistent and remained inconclusive. Therefore, we conducted a systematic review and meta-analysis to clarify the significance of HIF expression in RCC prognosis. PubMed, Embase, Web of Science, Cochrane Library, EBSCO, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Biological Abstracts were searched for eligible studies. Hazard ratio (HR) data for overall survival (OS), cancer-specific survival (CSS), and progression-free survival (PFS) with 95% confidence interval (CI) related to the expression status of HIF-1α or HIF-2α detected by immunohistochemistry were all extracted. Data were combined using a random- or fixed-effects model based on the corresponding inter-study heterogeneity. Subgroup analyses were also performed. A total of 14 studies composed of 1258 patients for HIF-1α evaluation and 619 patients for HIF-2α evaluation were included for further analysis. When initially analyzed as a whole, the HIF-1α expression was not significantly correlated with OS (HR 1.637, 95% CI 0.898-2.985, P = 0.108), CSS (HR 1.110, 95% CI 0.595-2.069, P = 0.744), and PFS (HR 1.113, 95% CI 0.675-1.836, P = 0.674). Similarly, HIF-2α expression was not significantly correlated with CSS (HR 1.597, 95% CI 0.667-3.824, P = 0.293) and PFS (HR 0.847, 95% CI 0.566-1.266, P = 0.417). However, subgroup analyses concerning subcellular localization of HIFs revealed that the high nuclear expression of HIF-1α was significantly associated with poor OS (HR 2.014, 95% CI 1.206-3.363, P = 0.007) and the high cytoplasmic expression of HIF -2α was significantly associated with poor CSS (HR 2.356, 95% CI 1.629-3.407, P = 0.000). The increased nuclear expression of HIF-1α and cytoplasmic expression of HIF-2α indicate unfavorable prognosis in RCC patients, which may serve as biomarkers

  4. The anti-proliferative effect of L-carnosine correlates with a decreased expression of hypoxia inducible factor 1 alpha in human colon cancer cells.

    Directory of Open Access Journals (Sweden)

    Barbara Iovine

    Full Text Available In recent years considerable attention has been given to the use of natural substances as anticancer drugs. The natural antioxidant dipeptide L-carnosine belongs to this class of molecules because it has been proved to have a significant anticancer activity both in vitro and in vivo. Previous studies have shown that L-carnosine inhibits the proliferation of human colorectal carcinoma cells by affecting the ATP and Reactive Oxygen Species (ROS production. In the present study we identified the Hypoxia-Inducible Factor 1α (HIF-1α as a possible target of L-carnosine in HCT-116 cell line. HIF-1α protein is over-expressed in multiple types of human cancer and is the major cause of resistance to drugs and radiation in solid tumours. Of particular interest are experimental data supporting the concept that generation of ROS provides a redox signal for HIF-1α induction, and it is known that some antioxidants are able to suppress tumorigenesis by inhibiting HIF-1α. In the current study we found that L-carnosine reduces the HIF-1α protein level affecting its stability and decreases the HIF-1 transcriptional activity. In addition, we demonstrated that L-carnosine is involved in ubiquitin-proteasome system promoting HIF-1α degradation. Finally, we compared the antioxidant activity of L-carnosine with that of two synthetic anti-oxidant bis-diaminotriazoles (namely 1 and 2, respectively. Despite these three compounds have the same ability in reducing intracellular ROS, 1 and 2 are more potent scavengers and have no effect on HIF-1α expression and cancer cell proliferation. These findings suggest that an analysis of L-carnosine antioxidant pathway will clarify the mechanism underlying the anti-proliferative effects of this dipeptide on colon cancer cells. However, although the molecular mechanism by which L-carnosine down regulates or inhibits the HIF-1α activity has not been yet elucidated, this ability may be promising in treating hypoxia

  5. The Protective Effect of Salidroside on Hypoxia-Induced Corpus Cavernosum Smooth Muscle Cell Phenotypic Transformation

    OpenAIRE

    Zhang, Xiang; Zhao, Jian-feng; Zhao, Fan; Yan, Jun-Feng; Yang, Fan; Huang, Xiao-jun; Chen, Gang; Fu, Hui-Ying; Lv, Bo-Dong

    2017-01-01

    Salidroside, a major active ingredient isolated from Rhodiola rosea, has a long application in Chinese medical history. It has widely demonstrated effects on fatigue, psychological stress, and depression and exhibits potential antihypoxia activity. Emerging evidence shows that hypoxia is an important independent risk factor for erectile dysfunction (ED). The aim of this study was to clarify the effect of salidroside on hypoxia-induced phenotypic transformation of corpus cavernosum smooth musc...

  6. The Protective Effect of Salidroside on Hypoxia-Induced Corpus Cavernosum Smooth Muscle Cell Phenotypic Transformation

    Directory of Open Access Journals (Sweden)

    Xiang Zhang

    2017-01-01

    Full Text Available Salidroside, a major active ingredient isolated from Rhodiola rosea, has a long application in Chinese medical history. It has widely demonstrated effects on fatigue, psychological stress, and depression and exhibits potential antihypoxia activity. Emerging evidence shows that hypoxia is an important independent risk factor for erectile dysfunction (ED. The aim of this study was to clarify the effect of salidroside on hypoxia-induced phenotypic transformation of corpus cavernosum smooth muscle cells (CCSMCs. Our results showed that salidroside decreased the hypoxia-induced expression of collagen and content of vimentin, a corpus cavernosum smooth muscle synthetic protein, in vitro. Simultaneously, salidroside increased expression of the CCSMC contractile proteins, α-smooth muscle actin (α-SMA and desmin. In vivo, similarly, the expressions of collagen and hypoxia-inducible factor-1α were increased in bilateral cavernous neurectomy (BCN rats while they were decreased in the salidroside group. Among the phenotypic proteins, α-SMA and desmin increased and vimentin decreased after treating BCN rats with salidroside compared with the BCN alone group. Overall, our results demonstrate that salidroside has the ability to oppose hypoxia and can inhibit the CCSMC phenotypic transformation induced by hypoxia. Salidroside may provide a new treatment method for ED.

  7. The Protective Effect of Salidroside on Hypoxia-Induced Corpus Cavernosum Smooth Muscle Cell Phenotypic Transformation.

    Science.gov (United States)

    Zhang, Xiang; Zhao, Jian-Feng; Zhao, Fan; Yan, Jun-Feng; Yang, Fan; Huang, Xiao-Jun; Chen, Gang; Fu, Hui-Ying; Lv, Bo-Dong

    2017-01-01

    Salidroside, a major active ingredient isolated from Rhodiola rosea, has a long application in Chinese medical history. It has widely demonstrated effects on fatigue, psychological stress, and depression and exhibits potential antihypoxia activity. Emerging evidence shows that hypoxia is an important independent risk factor for erectile dysfunction (ED). The aim of this study was to clarify the effect of salidroside on hypoxia-induced phenotypic transformation of corpus cavernosum smooth muscle cells (CCSMCs). Our results showed that salidroside decreased the hypoxia-induced expression of collagen and content of vimentin, a corpus cavernosum smooth muscle synthetic protein, in vitro. Simultaneously, salidroside increased expression of the CCSMC contractile proteins, α-smooth muscle actin (α-SMA) and desmin. In vivo, similarly, the expressions of collagen and hypoxia-inducible factor-1α were increased in bilateral cavernous neurectomy (BCN) rats while they were decreased in the salidroside group. Among the phenotypic proteins, α-SMA and desmin increased and vimentin decreased after treating BCN rats with salidroside compared with the BCN alone group. Overall, our results demonstrate that salidroside has the ability to oppose hypoxia and can inhibit the CCSMC phenotypic transformation induced by hypoxia. Salidroside may provide a new treatment method for ED.

  8. Vascular endothelial growth factor and hypoxia-inducible factor suppress chondrocyte apoptosis%血管内皮生长因子和缺氧诱导因子对软骨细胞凋亡的作用

    Institute of Scientific and Technical Information of China (English)

    周建林; 方洪松; 彭昊; 邓爽; 翁金清; 刘丰; 陈森; 周观金

    2015-01-01

    BACKGROUND:Osteoarthritis is a joint disease that primarily affects the cartilage. With the changes of the extracelular matrix, chondrocytes appear to have apoptosis. Vascular endothelial growth factor plays an important role in promoting endothelial cel division and proliferation and inducing angiogenesis. Hypoxia-inducible factor is a celular transcription factor and produces different reactions due to the oxygen content. Vascular endothelial growth factor and hypoxia-inducible factor are focused on inhibiting chondrocyte apoptosis. OBJECTIVE:To elaborate the effects of vascular endothelial growth factor and hypoxia-inducible factors on chondrocyte apoptosis. METHODS: Recent literatures related to chondrocyte apoptosis were summarized and analyzed. During the process of osteoarthritis, changes in vascular endothelial growth factors in chondrocytes and regulatory effects of vascular endothelial growth factor and hypoxia-inducible factor on chondrocyte apoptosis were elaborated.%背景:骨关节炎是一种关节疾病,主要影响软骨,随着软骨细胞胞外基质的变化,软骨细胞发生凋亡,血管内皮生长因子在促进血管内皮细胞分裂与增殖、诱导血管生成中起重要作用。缺氧诱导因子是一种在细胞环境中的转录因子,因氧含量而产生不同反应,血管内皮生长因子和缺氧诱导因子在抑制软骨细胞凋亡中的作用受到研究者的重视。目的:阐述血管内皮生长因子和缺氧诱导因子及其他可能因素对软骨细胞凋亡的影响。方法:分析、总结近年来软骨细胞凋亡的影响因素的相关文献,从骨关节炎进程中软骨细胞血管内皮生长因子表达变化,血管内皮生长因子和缺氧诱导因子对软骨细胞凋亡的调控等方面进行阐述。结果与结论:血管内皮生长因子通过上调抑制细胞凋亡因子的表达促进软骨细胞存活,缺氧诱导因子能增加软骨细胞

  9. Sodium hydrosulfide prevents hypoxia-induced behavioral impairment in neonatal mice.

    Science.gov (United States)

    Wang, Zhen; Zhan, Jingmin; Wang, Xueer; Gu, Jianhua; Xie, Kai; Zhang, Qingrui; Liu, Dexiang

    2013-11-13

    Hypoxic encephalopathy is a common cause of neonatal seizures and long-term neurological abnormalities. Endogenous hydrogen sulfide (H2S) may have multiple functions in brain. The aim of this study is to investigate whether sodium hydrosulfide (NaHS), a H2S donor, provides protection against neonatal hypoxia-induced neurobehavioral deficits. Neonatal mice were subjected to hypoxia (5% oxygen for 120min) at postnatal day 1 and received NaHS (5.6mg/kg) once daily for 3d. Neurobehavioral toxicity was examined at 3-30d after hypoxia. Treatment with NaHS significantly attenuated the delayed development of sensory and motor reflexes induced by hypoxia up to two weeks after the insult. Moreover, NaHS improved the learning and memory performance of hypoxic animals as indicated in Morris water maze test at 30d after hypoxia. In mice exposed to hypoxia, treatment with NaHS enhanced expression of brain derived neurotrophic factor (BDNF) in the hippocampus. Furthermore, the protective effects of NaHS were associated with its ability to repress the hypoxia-induced nitric oxide synthase (NOS) activity and nitric oxide production in the hippocampus of mice brain. Taken together, these results suggest that the long-lasting beneficial effects of NaHS on hypoxia-induced neurobehavioral deficits are mediated, at least in part, by inducing BDNF expression and suppressing NOS activity in the brain of mice.

  10. Use of Culture Geometry to Control Hypoxia-Induced Vascular Endothelial Growth Factor Secretion from Adipose-Derived Stem Cells: Optimizing a Cell-Based Approach to Drive Vascular Growth

    Science.gov (United States)

    Skiles, Matthew L.; Sahai, Suchit; Rucker, Lindsay

    2013-01-01

    Adipose-derived stem cells (ADSCs) possess potent angiogenic properties and represent a source for cell-based approaches to delivery of bioactive factors to drive vascularization of tissues. Hypoxic signaling appears to be largely responsible for triggering release of these angiogenic cytokines, including vascular endothelial growth factor (VEGF). Three-dimensional (3D) culture may promote activation of hypoxia-induced pathways, and has furthermore been shown to enhance cell survival by promoting cell–cell interactions while increasing angiogenic potential. However, the development of hypoxia within ADSC spheroids is difficult to characterize. In the present study, we investigated the impact of spheroid size on hypoxia-inducible transcription factor (HIF)-1 activity in spheroid cultures under atmospheric and physiological oxygen conditions using a fluorescent marker. Hypoxia could be induced and modulated by controlling the size of the spheroid; HIF-1 activity increased with spheroid size and with decreasing external oxygen concentration. Furthermore, VEGF secretion was impacted by the hypoxic status of the culture, increasing with elevated HIF-1 activity, up to the point at which viability was compromised. Together, these results suggest the ability to use 3D culture geometry as a means to control output of angiogenic factors from ADSCs, and imply that at a particular environmental oxygen concentration an optimal culture size for cytokine production exists. Consideration of culture geometry and microenvironmental conditions at the implantation site will be important for successful realization of ADSCs as a pro-angiogenic therapy. PMID:23668629

  11. Human intermittent hypoxia-induced respiratory plasticity is not caused by inflammation.

    Science.gov (United States)

    Beaudin, Andrew E; Waltz, Xavier; Pun, Matiram; Wynne-Edwards, Katherine E; Ahmed, Sofia B; Anderson, Todd J; Hanly, Patrick J; Poulin, Marc J

    2015-10-01

    Ventilatory instability, reflected by enhanced acute hypoxic (AHVR) and hypercapnic (AHCVR) ventilatory responses is a fundamental component of obstructive sleep apnoea (OSA) pathogenesis. Intermittent hypoxia-induced inflammation is postulated to promote AHVR enhancement in OSA, although the role of inflammation in intermittent hypoxia-induced respiratory changes in humans has not been examined. Thus, this study assessed the role of inflammation in intermittent hypoxia-induced respiratory plasticity in healthy humans.In a double-blind, placebo-controlled, randomised crossover study design, 12 males were exposed to 6 h of intermittent hypoxia on three occasions. Prior to intermittent hypoxia exposures, participants ingested (for 4  days) either placebo or the nonsteroidal anti-inflammatory drugs indomethacin (nonselective cyclooxygenase (COX) inhibitor) and celecoxib (selective COX-2 inhibitor). Pre- and post-intermittent hypoxia resting ventilation, AHVR, AHCVR and serum concentration of the pro-inflammatory cytokine tumour necrosis factor (TNF)-α were assessed.Pre-intermittent hypoxia resting ventilation, AHVR, AHCVR and TNF-α concentrations were similar across all three conditions (p≥0.093). Intermittent hypoxia increased resting ventilation and the AHVR similarly across all conditions (p=0.827), while the AHCVR was increased (p=0.003) and TNF-α was decreased (p=0.006) with only selective COX-2 inhibition.These findings indicate that inflammation does not contribute to human intermittent hypoxia-induced respiratory plasticity. Moreover, selective COX-2 inhibition augmented the AHCVR following intermittent hypoxia exposure, suggesting that selective COX-2 inhibition could exacerbate OSA severity by increasing ventilatory instability.

  12. Bacopa monniera leaf extract ameliorates hypobaric hypoxia induced spatial memory impairment.

    Science.gov (United States)

    Hota, Sunil Kumar; Barhwal, Kalpana; Baitharu, Iswar; Prasad, Dipti; Singh, Shashi Bala; Ilavazhagan, Govindasamy

    2009-04-01

    Hypobaric hypoxia induced memory impairment has been attributed to several factors including increased oxidative stress, depleted mitochondrial bioenergetics, altered neurotransmission and apoptosis. This multifactorial response of the brain to hypobaric hypoxia limits the use of therapeutic agents that target individual pathways for ameliorating hypobaric hypoxia induced memory impairment. The present study aimed at exploring the therapeutic potential of a bacoside rich leaf extract of Bacopa monniera in improving the memory functions in hypobaric conditions. The learning ability was evaluated in male Sprague Dawley rats along with memory retrieval following exposure to hypobaric conditions simulating an altitude of 25,000 ft for different durations. The effect of bacoside administration on apoptosis, cytochrome c oxidase activity, ATP levels, and oxidative stress markers and on plasma corticosterone levels was investigated. Expression of NR1 subunit of N-methyl-d-aspartate receptors, neuronal cell adhesion molecules and was also studied along with CREB phosphorylation to elucidate the molecular mechanisms of bacoside action. Bacoside administration was seen to enhance learning ability in rats along with augmentation in memory retrieval and prevention of dendritic atrophy following hypoxic exposure. In addition, it decreased oxidative stress, plasma corticosterone levels and neuronal degeneration. Bacoside administration also increased cytochrome c oxidase activity along with a concomitant increase in ATP levels. Hence, administration of bacosides could be a useful therapeutic strategy in ameliorating hypobaric hypoxia induced cognitive dysfunctions and other related neurological disorders.

  13. Midazolam inhibits the hypoxia-induced up-regulation of erythropoietin in the central nervous system.

    Science.gov (United States)

    Matsuyama, Tomonori; Tanaka, Tomoharu; Tatsumi, Kenichiro; Daijo, Hiroki; Kai, Shinichi; Harada, Hiroshi; Fukuda, Kazuhiko

    2015-08-15

    Erythropoietin (EPO), a regulator of red blood cell production, is endogenously expressed in the central nervous system. It is mainly produced by astrocytes under hypoxic conditions and has proven to have neuroprotective and neurotrophic effects. In the present study, we investigated the effect of midazolam on EPO expression in primary cultured astrocytes and the mouse brain. Midazolam was administered to 6-week-old BALB/c male mice under hypoxic conditions and pregnant C57BL/6N mice under normoxic conditions. Primary cultured astrocytes were also treated with midazolam under hypoxic conditions. The expression of EPO mRNA in mice brains and cultured astrocytes was studied. In addition, the expression of hypoxia-inducible factor (HIF), known as the main regulator of EPO, was evaluated. Midazolam significantly reduced the hypoxia-induced up-regulation of EPO in BALB/c mice brains and primary cultured astrocytes and suppressed EPO expression in the fetal brain. Midazolam did not affect the total amount of HIF proteins but significantly inhibited the nuclear expression of HIF-1α and HIF-2α proteins. These results demonstrated the suppressive effects of midazolam on the hypoxia-induced up-regulation of EPO both in vivo and in vitro.

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

    Directory of Open Access Journals (Sweden)

    Stefan K Alig

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

  15. Cytoprotective effects of fisetin against hypoxia-induced cell death in PC12 cells.

    Science.gov (United States)

    Chen, Pei-Yi; Ho, Yi-Ru; Wu, Ming-Jiuan; Huang, Shun-Ping; Chen, Po-Kong; Tai, Mi-Hsueh; Ho, Chi-Tang; Yen, Jui-Hung

    2015-01-01

    Fisetin (3,7,3',4'-tetrahydroxyflavone), a flavonol compound of flavonoids, exhibits a broad spectrum of biological activities including anti-oxidant, anti-inflammatory, anti-cancer and neuroprotective effects. The aim of this study is to investigate the cytoprotective effect of fisetin and the underlying molecular mechanism against hypoxia-induced cell death in PC12 cells. The results of this study showed that fisetin significantly restored the cell viability of PC12 cells under both cobalt chloride (CoCl₂)- and low oxygen-induced hypoxic conditions. Treatment with fisetin successfully reduced the CoCl₂-mediated reactive oxygen species (ROS) production, which was accompanied by an increase in the cell viability of PC12 cells. Furthermore, we found that treatment of PC12 cells with fisetin markedly upregulated hypoxia-inducible factor 1α (HIF-1α), its nuclear accumulation and the hypoxia-response element (HRE)-driven transcriptional activation. The fisetin-mediated cytoprotection during CoCl₂ exposure was significantly attenuated through the administration of HIF-1α siRNA. Moreover, we demonstrated that MAPK/ERK kinase 1/2 (MEK1/2), p38 MAPK and phosphatidylinositol 3-kinase (PI3 K) inhibitors significantly blocked the increase in cell survival that was induced by fisetin treatment under hypoxic conditions. Consistently, increased phosphorylation of ERK, p38 and Akt proteins was observed in PC12 cells treated with fisetin. However, the fisetin-induced HRE-driven transcription was not affected by inhibition of these kinase signaling pathways. Current results reveal for the first time that fisetin promotes cell survival and protects against hypoxia-induced cell death through ROS scavenging and the activation of HIF1α-, MAPK/ERK-, p38 MAPK- and PI3 K/Akt-dependent signaling pathways in PC12 cells.

  16. Induction of erythropoiesis by hypoxia-inducible factor prolyl hydroxylase inhibitors without promotion of tumor initiation, progression, or metastasis in a VEGF-sensitive model of spontaneous breast cancer

    Science.gov (United States)

    Seeley, Todd W; Sternlicht, Mark D; Klaus, Stephen J; Neff, Thomas B; Liu, David Y

    2017-01-01

    The effects of pharmacological hypoxia-inducible factor (HIF) stabilization were investigated in the MMTV-Neundl-YD5 (NeuYD) mouse model of breast cancer. This study first confirmed the sensitivity of this model to increased vascular endothelial growth factor (VEGF), using bigenic NeuYD;MMTV-VEGF-25 mice. Tumor initiation was dramatically accelerated in bigenic animals. Bigenic tumors were also more aggressive, with shortened doubling times and increased lung metastasis as compared to NeuYD controls. In separate studies, NeuYD mice were treated three times weekly from 7 weeks of age until study end with two different HIF prolyl hydroxylase inhibitors (HIF-PHIs), FG-4497 or roxadustat (FG-4592). In NeuYD mice, HIF-PHI treatments elevated erythropoiesis markers, but no differences were detected in tumor onset or the phenotypes of established tumors. PMID:28331872

  17. Induction of erythropoiesis by hypoxia-inducible factor prolyl hydroxylase inhibitors without promotion of tumor initiation, progression, or metastasis in a VEGF-sensitive model of spontaneous breast cancer.

    Science.gov (United States)

    Seeley, Todd W; Sternlicht, Mark D; Klaus, Stephen J; Neff, Thomas B; Liu, David Y

    2017-01-01

    The effects of pharmacological hypoxia-inducible factor (HIF) stabilization were investigated in the MMTV-Neu(ndl)-YD5 (NeuYD) mouse model of breast cancer. This study first confirmed the sensitivity of this model to increased vascular endothelial growth factor (VEGF), using bigenic NeuYD;MMTV-VEGF-25 mice. Tumor initiation was dramatically accelerated in bigenic animals. Bigenic tumors were also more aggressive, with shortened doubling times and increased lung metastasis as compared to NeuYD controls. In separate studies, NeuYD mice were treated three times weekly from 7 weeks of age until study end with two different HIF prolyl hydroxylase inhibitors (HIF-PHIs), FG-4497 or roxadustat (FG-4592). In NeuYD mice, HIF-PHI treatments elevated erythropoiesis markers, but no differences were detected in tumor onset or the phenotypes of established tumors.

  18. Hypoxia-inducible factor 1α (HIF-1α) and reactive oxygen species (ROS) mediates radiation-induced invasiveness through the SDF-1α/CXCR4 pathway in non-small cell lung carcinoma cells.

    Science.gov (United States)

    Gu, Qing; He, Yan; Ji, Jianfeng; Yao, Yifan; Shen, Wenhao; Luo, Jialin; Zhu, Wei; Cao, Han; Geng, Yangyang; Xu, Jing; Zhang, Shuyu; Cao, Jianping; Ding, Wei-Qun

    2015-05-10

    Radiotherapy is an important procedure for the treatment of inoperable non-small cell lung cancer (NSCLC). However, recent evidence has shown that irradiation can promote the invasion and metastasis of several types of cancer, and the underlying mechanisms are not fully understood. This study aimed to investigate the molecular mechanism by which radiation enhances the invasiveness of NSCLC cells. We found that after irradiation, hypoxia-inducible factor 1α (HIF-1α) was increased and translocated into the nucleus, where it bound to the hypoxia response element (HRE) in the CXCR4 promoter and promoted the transcription of CXCR4. Furthermore, reactive oxygen species (ROS) also plays a role in the radiation-induced expression of CXCR4. Our results revealed that 2 Gy X-ray irradiation promoted the metastasis and invasiveness of H1299, A549 and H460 cells, which were significantly enhanced by SDF-1α treatment. Blocking the SDF-1α/CXCR4 interaction could suppress the radiation-induced invasiveness of NSCLC cells. The PI3K/pAkt and MAPK/pERK1/2 pathways were found to be involved in radiation-induced matrix metalloproteinase (MMP) expression. In vivo, irradiation promoted the colonization of H1299 cells in the liver and lung, which was mediated by CXCR4. Altogether, our findings have elucidated the underlying mechanisms of the irradiation-enhanced invasiveness of NSCLC cells.

  19. The effect of insulin-loaded linear poly(ethylene glycol)-brush-like poly(l-lysine) block copolymer on renal ischemia/reperfusion-induced lung injury through downregulating hypoxia-inducible factor.

    Science.gov (United States)

    Tong, Fei; Tang, Xiangyuan; Li, Xin; Xia, Wenquan; Liu, Daojun

    2016-01-01

    The aim of this study was to observe the therapeutic effect of insulin-loaded linear poly(ethylene glycol)-brush-like poly(l-lysine) block copolymer poly(ethylene glycol)-b-(poly(ethylenediamine l-glutamate)-g-poly(l-lysine)) (PEG-b-(PELG-g-PLL) on renal ischemia/reperfusion-induced lung injury through downregulating hypoxia-inducible factor (HIF) as compared to free insulin. Sprague Dawley rats were pretreated with 30 U/kg insulin or insulin/PEG-b-(PELG-g-PLL) complex, and then subjected to 45 minutes of ischemia and 24 hours of reperfusion. The blood and lungs were collected, the level of serum creatinine and blood urea nitrogen were measured, and the dry/wet lung ratios, the activity of superoxide dismutase and myeloperoxidase, the content of methane dicarboxylic aldehyde and tumor necrosis factor-α, and the expression of HIF-1α and vascular endothelial growth factor (VEGF) were measured in pulmonary tissues. Both insulin and insulin/PEG-b-(PELG-g-PLL) preconditioning improved the recovery of renal function, reduced pulmonary oxidative stress injury, restrained inflammatory damage, and downregulated the expression of HIF-1α and VEGF as compared to ischemia/reperfusion group, while insulin/PEG-b-(PELG-g-PLL) significantly improved this effect.

  20. The effect of insulin-loaded linear poly(ethylene glycol)-brush-like poly(l-lysine) block copolymer on renal ischemia/reperfusion-induced lung injury through downregulating hypoxia-inducible factor

    Science.gov (United States)

    Tong, Fei; Tang, Xiangyuan; Li, Xin; Xia, Wenquan; Liu, Daojun

    2016-01-01

    The aim of this study was to observe the therapeutic effect of insulin-loaded linear poly(ethylene glycol)-brush-like poly(l-lysine) block copolymer poly(ethylene glycol)-b-(poly(ethylenediamine l-glutamate)-g-poly(l-lysine)) (PEG-b-(PELG-g-PLL) on renal ischemia/reperfusion-induced lung injury through downregulating hypoxia-inducible factor (HIF) as compared to free insulin. Sprague Dawley rats were pretreated with 30 U/kg insulin or insulin/PEG-b-(PELG-g-PLL) complex, and then subjected to 45 minutes of ischemia and 24 hours of reperfusion. The blood and lungs were collected, the level of serum creatinine and blood urea nitrogen were measured, and the dry/wet lung ratios, the activity of superoxide dismutase and myeloperoxidase, the content of methane dicarboxylic aldehyde and tumor necrosis factor-α, and the expression of HIF-1α and vascular endothelial growth factor (VEGF) were measured in pulmonary tissues. Both insulin and insulin/PEG-b-(PELG-g-PLL) preconditioning improved the recovery of renal function, reduced pulmonary oxidative stress injury, restrained inflammatory damage, and downregulated the expression of HIF-1α and VEGF as compared to ischemia/reperfusion group, while insulin/PEG-b-(PELG-g-PLL) significantly improved this effect. PMID:27175073

  1. Sulforaphane inhibits hypoxia-induced HIF-1α and VEGF expression and migration of human colon cancer cells.

    Science.gov (United States)

    Kim, Dong Hwan; Sung, Bokyung; Kang, Yong Jung; Hwang, Seong Yeon; Kim, Min Jeong; Yoon, Jeong-Hyun; Im, Eunok; Kim, Nam Deuk

    2015-12-01

    The effects of sulforaphane (a natural product commonly found in broccoli) was investigated on hypoxia inducible factor-1α (HIF-1α) expression in HCT116 human colon cancer cells and AGS human gastric cancer cells. We found that hypoxia-induced HIF-1α protein expression in HCT116 and AGS cells, while treatment with sulforaphane markedly and concentration-dependently inhibited HIF-1α expression in both cell lines. Treatment with sulforaphane inhibited hypoxia-induced vascular endothelial growth factor (VEGF) expression in HCT116 cells. Treatment with sulforaphane modulated the effect of hypoxia on HIF-1α stability. However, degradation of HIF-1α by sulforaphane was not mediated through the 26S proteasome pathway. We also found that the inhibition of HIF-1α by sulforaphane was not mediated through AKT and extracellular signal-regulated kinase phosphorylation under hypoxic conditions. Finally, hypoxia-induced HCT116 cell migration was inhibited by sulforaphane. These data suggest that sulforaphane may inhibit human colon cancer progression and cancer cell angiogenesis by inhibiting HIF-1α and VEGF expression. Taken together, these results indicate that sulforaphane is a new and potent chemopreventive drug candidate for treating patients with human colon cancer.

  2. Hypoxia-induced reactive oxygen species cause chromosomal abnormalities in endothelial cells in the tumor microenvironment.

    Directory of Open Access Journals (Sweden)

    Miyako Kondoh

    Full Text Available There is much evidence that hypoxia in the tumor microenvironment enhances tumor progression. In an earlier study, we reported abnormal phenotypes of tumor-associated endothelial cells such as those resistant to chemotherapy and chromosomal instability. Here we investigated the role of hypoxia in the acquisition of chromosomal abnormalities in endothelial cells. Tumor-associated endothelial cells isolated from human tumor xenografts showed chromosomal abnormalities, >30% of which were aneuploidy. Aneuploidy of the tumor-associated endothelial cells was also shown by simultaneous in-situ hybridization for chromosome 17 and by immunohistochemistry with anti-CD31 antibody for endothelial staining. The aneuploid cells were surrounded by a pimonidazole-positive area, indicating hypoxia. Human microvascular endothelial cells expressed hypoxia-inducible factor 1 and vascular endothelial growth factor A in response to either hypoxia or hypoxia-reoxygenation, and in these conditions, they acquired aneuploidy in 7 days. Induction of aneuploidy was inhibited by either inhibition of vascular endothelial growth factor signaling with vascular endothelial growth factor receptor 2 inhibitor or by inhibition of reactive oxygen species by N-acetyl-L-cysteine. These results indicate that hypoxia induces chromosomal abnormalities in endothelial cells through the induction of reactive oxygen species and excess signaling of vascular endothelial growth factor in the tumor microenvironment.

  3. Hypoxia-Induced Reactive Oxygen Species Cause Chromosomal Abnormalities in Endothelial Cells in the Tumor Microenvironment

    Science.gov (United States)

    Hida, Yasuhiro; Maishi, Nako; Towfik, Alam Mohammad; Inoue, Nobuo; Shindoh, Masanobu; Hida, Kyoko

    2013-01-01

    There is much evidence that hypoxia in the tumor microenvironment enhances tumor progression. In an earlier study, we reported abnormal phenotypes of tumor-associated endothelial cells such as those resistant to chemotherapy and chromosomal instability. Here we investigated the role of hypoxia in the acquisition of chromosomal abnormalities in endothelial cells. Tumor-associated endothelial cells isolated from human tumor xenografts showed chromosomal abnormalities, >30% of which were aneuploidy. Aneuploidy of the tumor-associated endothelial cells was also shown by simultaneous in-situ hybridization for chromosome 17 and by immunohistochemistry with anti-CD31 antibody for endothelial staining. The aneuploid cells were surrounded by a pimonidazole-positive area, indicating hypoxia. Human microvascular endothelial cells expressed hypoxia-inducible factor 1 and vascular endothelial growth factor A in response to either hypoxia or hypoxia-reoxygenation, and in these conditions, they acquired aneuploidy in 7 days. Induction of aneuploidy was inhibited by either inhibition of vascular endothelial growth factor signaling with vascular endothelial growth factor receptor 2 inhibitor or by inhibition of reactive oxygen species by N-acetyl-L-cysteine. These results indicate that hypoxia induces chromosomal abnormalities in endothelial cells through the induction of reactive oxygen species and excess signaling of vascular endothelial growth factor in the tumor microenvironment. PMID:24260373

  4. Differential sensitivity of oxidative and glycolytic muscles to hypoxia-induced muscle atrophy.

    Science.gov (United States)

    de Theije, C C; Langen, R C J; Lamers, W H; Gosker, H R; Schols, A M W J; Köhler, S E

    2015-01-15

    Hypoxia as a consequence of acute and chronic respiratory disease has been associated with muscle atrophy. This study investigated the sensitivity of oxidative and glycolytic muscles to hypoxia-induced muscle atrophy. Male mice were exposed to 8% normobaric oxygen for up to 21 days. Oxidative soleus and glycolytic extensor digitorum longus (EDL) muscles were isolated, weighed, and assayed for expression profiles of the ubiquitin-proteasome system (UPS), the autophagy-lysosome pathway (ALP), and glucocorticoid receptor (GR) and hypoxia-inducible factor-1α (HIF1α) signaling. Fiber-type composition and the capillary network were investigated. Hypoxia-induced muscle atrophy was more prominent in the EDL than the soleus muscle. Although increased expression of HIF1α target genes showed that both muscle types sensed hypoxia, their adaptive responses differed. Atrophy consistently involved a hypoxia-specific effect (i.e., not attributable to a hypoxia-mediated reduction of food intake) in the EDL only. Hypoxia-specific activation of the UPS and ALP and increased expression of the glucocorticoid receptor (Gr) and its target genes were also mainly observed in the EDL. In the soleus, stimulation of gene expression of those pathways could be mimicked to a large extent by food restriction alone. Hypoxia increased the number of capillary contacts per fiber cross-sectional area in both muscles. In the EDL, this was due to type II fiber atrophy, whereas in the soleus the absolute number of capillary contacts increased. These responses represent two distinct modes to improve oxygen supply to muscle fibers, but may aggravate muscle atrophy in chronic obstructive pulmonary disease patients who have a predominance of type II fibers.

  5. [Effects of Chinese herbs for replenishing qi and resolving stagnation on hypoxia-inducible factor-1alpha and vascular endothelial growth factor in granulation tissue of skin ulcers in rats with diabetes].

    Science.gov (United States)

    Que, Hua-fa; Zhu, Yuan-yin; Wang, Yun-fei; Zhang, Zhen; Xu, Jie-nan; Xing, Jie; Tang, Han-jun

    2007-03-01

    To explore the effects of Chinese herbs for replenishing qi and resolving stagnation on hypoxia-inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) in granulation tissue of skin ulcers in rats with syndrome of blood stasis and qi deficiency. Diabetic rats with back full-thickness skin lesion and syndrome of blood stasis and qi deficiency were divided in to five groups: untreated group, basic fibroblast growth factor (bFGF)-treated group, Yiqi Huayu Recipe (a recipe for replenishing qi and resolving stagnation)-treated group, Yiqi Recipe (a recipe for replenishing qi)-treated group and Huayu Recipe (a recipe for resolving stagnation)-treated group, and another eight normal rats served as normal control group. Immunohistochemical method and image analysis were used to test the expressions of HIF-1alpha and VEGF in granulation tissue of skin ulcers in rats with diabetes. In the untreated group, the expression of HIF-1alpha was significantly increased and the expression of VEGF was significantly decreased as compared with those in the normal control group (PChinese herbs for replenishing qi and resolving stagnation can promote the wound healing in rats through reducing the expression of HIF-1alpha, accelerating the expression of VEGF in granulation tissue of skin ulcers in rats with diabetes and ameliorating the status of ischemia and hypoxia.

  6. Presurgical Botulinum Toxin A Treatment Increases Angiogenesis by Hypoxia-Inducible Factor-1α/Vascular Endothelial Growth Factor and Subsequent Superiorly Based Transverse Rectus Abdominis Myocutaneous Flap Survival in a Rat Model.

    Science.gov (United States)

    Park, Tae Hwan; Lee, Song Hyun; Park, Yun Joo; Lee, Young Seok; Rah, Dong Kyun; Kim, Sung Young

    2016-06-01

    To date, there have been several experimental studies to assess tissue viability of transverse rectus abdominis myocutaneous (TRAM) flaps. Botulinum toxin A (BoTA) has gained popularity in many clinical fields, for a variety of therapeutic and aesthetic purposes. In addition, there have been reports regarding the positive effect of BoTA on flap survival by various mechanisms. In this study, we hypothesized that pretreatment with BoTA could augment the survival of TRAM flaps via increased hypoxia-inducible factor (HIF)1α/vascular endothelial growth factor (VEGF)-dependent angiogenesis.Twenty-four Sprague-Dawley rats were randomly divided into 2 groups: a control group and a BoTA group. Five days before superiorly based TRAM flap elevation, the BoTA group was pretreated with BoTA, whereas the control group was pretreated with normal saline. Gross flap survival rates were assessed, and quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) and Western blotting were performed for the evaluation of angiogenesis-related factors (CD34, HIF-1α, and VEGF).In the BoTA group, the gross flap survival rate was significantly higher than that in the control group on both ipsilateral (92.78.3 ± 5.05% vs 86.8 ± 3.88%, P = 0.009) and contralateral (91.57 ± 5.79% vs 74.28 ± 11.83%, P model.

  7. Production of Hypoxia-induced Corneal Edema in Aged Eyes

    Institute of Scientific and Technical Information of China (English)

    Alan K. Cheung; Andrew W. Siu; Digby W. Cheung; Edwin C. Mo

    2004-01-01

    Purpose:Corneal thickness assessment is a common clinical procedure applied in corneal and contact lens care. This study aims to investigate the effect of age on hypoxiainduced corneal swelling.Methods:Eighteen male subjects were equally divided into the younger [(23.7±0.8) and older [(74.4±2.5) years old]groups.Each subject wore a thick soft contact lens (uniform thickness of 0.3 mm) on the left cornea. With the contact lens in place, the baseline central corneal thickness was measured using a specially designed photo-pachometer. The lens was then patched behind the closed eyelids, producing an extremely hypoxic stress to the cornea. The change in central corneal thickness was monitored every 20 minutes with momentary disruptions to the hypoxic stress over the next 2 hours. The increase in thickness was taken as an index of corneal edema. The rate of change in corneal thickness, as derived from a non-linear mathematical model, was compared between groups. Results:The corneal thickness of both age groups increased significantly with time (P<0.000 1 ). The mean corneal swelling constant for the older subjects was 16.5 × 10-3 (S.E.M. = 2.65 × 10-3) and the value for the younger subjects was 46.5 × 10-3 (S.E.M. = 3.25× 10-3). The difference was statistically significant (P < 0.000 1 ).Conclusion:Aging cornea has a slower hypoxia-induced edema response compared with the younger group. Whether it is caused by a decreased corneal lactate production or an increased resistance to physical expansion deserves further investigation. Eye Science2004;20:1-5.

  8. In Vivo Imaging Reveals Significant Tumor Vascular Dysfunction and Increased Tumor Hypoxia-Inducible Factor-1α Expression Induced by High Single-Dose Irradiation in a Pancreatic Tumor Model.

    Science.gov (United States)

    Maeda, Azusa; Chen, Yonghong; Bu, Jiachuan; Mujcic, Hilda; Wouters, Bradly G; DaCosta, Ralph S

    2017-01-01

    To investigate the effect of high-dose irradiation on pancreatic tumor vasculature and microenvironment using in vivo imaging techniques. A BxPC3 pancreatic tumor xenograft was established in a dorsal skinfold window chamber model and a subcutaneous hind leg model. Tumors were irradiated with a single dose of 4, 12, or 24 Gy. The dorsal skinfold window chamber model was used to assess tumor response, vascular function and permeability, platelet and leukocyte adhesion to the vascular endothelium, and tumor hypoxia for up to 14 days after 24-Gy irradiation. The hind leg model was used to monitor tumor size, hypoxia, and vascularity for up to 65 days after 24-Gy irradiation. Tumors were assessed histologically to validate in vivo observations. In vivo fluorescence imaging revealed temporary vascular dysfunction in tumors irradiated with a single dose of 4 to 24 Gy, but most significantly with a single dose of 24 Gy. Vascular functional recovery was observed by 14 days after irradiation in a dose-dependent manner. Furthermore, irradiation with 24 Gy caused platelet and leukocyte adhesion to the vascular endothelium within hours to days after irradiation. Vascular permeability was significantly higher in irradiated tumors compared with nonirradiated controls 14 days after irradiation. This observation corresponded with increased expression of hypoxia-inducible factor-1α in irradiated tumors. In the hind leg model, irradiation with a single dose of 24 Gy led to tumor growth delay, followed by tumor regrowth. Irradiation of the BxPC3 tumors with a single dose of 24 Gy caused transient vascular dysfunction and increased expression of hypoxia-inducible factor-1α. Such biological changes may impact tumor response to high single-dose and hypofractionated irradiation, and further investigations are needed to better understand the clinical outcomes of stereotactic body radiation therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Hypoxia-Induced Collagen Synthesis of Human Lung Fibroblasts by Activating the Angiotensin System

    Directory of Open Access Journals (Sweden)

    Shan-Shan Liu

    2013-12-01

    Full Text Available The exact molecular mechanism that mediates hypoxia-induced pulmonary fibrosis needs to be further clarified. The aim of this study was to explore the effect and underlying mechanism of angiotensin II (Ang II on collagen synthesis in hypoxic human lung fibroblast (HLF cells. The HLF-1 cell line was used for in vitro studies. Angiotensinogen (AGT, angiotensin converting enzyme (ACE, angiotensin II type 1 receptor (AT1R and angiotensin II type 2 receptor (AT2R expression levels in human lung fibroblasts were analysed using real-time polymerase chain reaction (RT-PCR after hypoxic treatment. Additionally, the collagen type I (Col-I, AT1R and nuclear factor κappaB (NF-κB protein expression levels were detected using Western blot analysis, and NF-κB nuclear translocation was measured using immunofluorescence localization analysis. Ang II levels in HLF-1 cells were measured with an enzyme-linked immunosorbent assay (ELISA. We found that hypoxia increased Col-I mRNA and protein expression in HLF-1 cells, and this effect could be inhibited by an AT1R or AT2R inhibitor. The levels of NF-κB, RAS components and Ang II production in HLF-1 cells were significantly increased after the hypoxia exposure. Hypoxia or Ang II increased NF-κB-p50 protein expression in HLF-1 cells, and the special effect could be inhibited by telmisartan (TST, an AT1R inhibitor, and partially inhibited by PD123319, an AT2R inhibitor. Importantly, hypoxia-induced NF-κB nuclear translocation could be nearly completely inhibited by an AT1R or AT2R inhibitor. Furthermore pyrrolidine dithiocarbamate (PDTC, a NF-κB blocker, abolished the expression of hypoxia-induced AT1R and Col-I in HLF-1 cells. Our results indicate that Ang II-mediated NF-κB signalling via ATR is involved in hypoxia-induced collagen synthesis in human lung fibroblasts.

  10. Role of hypoxia-related proteins in invasion of ameloblastoma cells: crosstalk between NOTCH1, hypoxia-inducible factor 1α, a disintegrin and metalloproteinase 12, and heparin-binding epidermal growth factor.

    Science.gov (United States)

    da Costa, Natacha Malu Miranda; Fialho, Amanda Dalla Vechia; Proietti, Carolina Carmine; da Silva Kataoka, Maria Sueli; Jaeger, Ruy Gastaldoni; de Alves-Júnior, Sérgio Melo; de Jesus Viana Pinheiro, João

    2016-07-01

    Ameloblastoma AME is a benign tumour characterized by local invasiveness, high recurrence rates, and diverse histological patterns. The oxygen concentration is reduced in specific areas of the tumour microenvironment, which leads to intratumoral hypoxia. Crosstalk between NOTCH1, a disintegrin and metalloproteinase 12 (ADAM-12), hypoxia-inducible factor 1α (HIF-1α) and heparin-binding epidermal growth factor (HB-EGF) under hypoxic conditions has been implicated in invadopodia formation, tumour invasiveness, and metastasis development. The aim of this study was to analyse the expression of these proteins, in order to further elucidate the mechanisms underlying AME invasiveness. Twenty cases of AME, eight calcifying cystic odontogenic tumours CCOTs and 10 samples of dental follicle were used to investigate the expression of these proteins by immunohistochemistry with the primary antibodies anti-NOTCH1, anti-ADAM-12, anti-HIF-1α, and anti-HB-EGF. Immunostaining results were expressed as the percentage of stained area in images acquired in an AxioScope microscope equipped with an AxioCamHRc camera and a × 40 objective. The results showed that immunoexpression of all proteins was higher in the AME samples than in the CCOT and dental follicle samples (P < 0.05). AME showed an increased presence of proteins associated with tumour invasiveness, which indicates a possible role of these proteins in the biological behaviour of this tumour. © 2015 John Wiley & Sons Ltd.

  11. Helicobacter pylori Induced Phosphatidylinositol-3-OH Kinase/mTOR Activation Increases Hypoxia Inducible Factor-1α to Promote Loss of Cyclin D1 and G0/G1 Cell Cycle Arrest in Human Gastric Cells

    Science.gov (United States)

    Canales, Jimena; Valenzuela, Manuel; Bravo, Jimena; Cerda-Opazo, Paulina; Jorquera, Carla; Toledo, Héctor; Bravo, Denisse; Quest, Andrew F. G.

    2017-01-01

    Helicobacter pylori (H. pylori) is a human gastric pathogen that has been linked to the development of several gastric pathologies, such as gastritis, peptic ulcer, and gastric cancer. In the gastric epithelium, the bacterium modifies many signaling pathways, resulting in contradictory responses that favor both proliferation and apoptosis. Consistent with such observations, H. pylori activates routes associated with cell cycle progression and cell cycle arrest. H. pylori infection also induces the hypoxia-induced factor HIF-1α, a transcription factor known to promote expression of genes that permit metabolic adaptation to the hypoxic environment in tumors and angiogenesis. Recently, however, also roles for HIF-1α in the repair of damaged DNA and inhibition of gene expression were described. Here, we investigated signaling pathways induced by H. pylori in gastric cells that favor HIF-1α expression and the consequences thereof in infected cells. Our results revealed that H. pylori promoted PI3K/mTOR-dependent HIF-1α induction, HIF-1α translocation to the nucleus, and activity as a transcription factor as evidenced using a reporter assay. Surprisingly, however, transcription of known HIF-1α effector genes evaluated by qPCR analysis, revealed either no change (LDHA and GAPDH), statistically insignificant increases SLC2A1 (GLUT-1) or greatly enhance transcription (VEGFA), but in an HIF-1α-independent manner, as quantified by PCR analysis in cells with shRNA-mediated silencing of HIF-1α. Instead, HIF-1α knockdown facilitated G1/S progression and increased Cyclin D1 protein half-life, via a post-translational pathway. Taken together, these findings link H. pylori-induced PI3K-mTOR activation to HIF-1α induced G0/G1 cell cycle arrest by a Cyclin D1-dependent mechanism. Thus, HIF-1α is identified here as a mediator between survival and cell cycle arrest signaling activated by H. pylori infection. PMID:28401064

  12. Hypoxia induces mitochondrial mutagenesis and dysfunction in inflammatory arthritis.

    LENUS (Irish Health Repository)

    Biniecka, Monika

    2012-02-01

    OBJECTIVE: To assess the levels and spectrum of mitochondrial DNA (mtDNA) point mutations in synovial tissue from patients with inflammatory arthritis in relation to in vivo hypoxia and oxidative stress levels. METHODS: Random Mutation Capture assay was used to quantitatively evaluate alterations of the synovial mitochondrial genome. In vivo tissue oxygen levels (tPO(2)) were measured at arthroscopy using a Licox probe. Synovial expression of lipid peroxidation (4-hydroxynonenal [4-HNE]) and mitochondrial cytochrome c oxidase subunit II (CytcO II) deficiency were assessed by immunohistochemistry. In vitro levels of mtDNA point mutations, reactive oxygen species (ROS), mitochondrial membrane potential, and markers of oxidative DNA damage (8-oxo-7,8-dihydro-2\\'-deoxyguanine [8-oxodG]) and lipid peroxidation (4-HNE) were determined in human synoviocytes under normoxia and hypoxia (1%) in the presence or absence of superoxide dismutase (SOD) or N-acetylcysteine (NAC) or a hydroxylase inhibitor (dimethyloxalylglycine [DMOG]). Patients were categorized according to their in vivo tPO(2) level (<20 mm Hg or >20 mm Hg), and mtDNA point mutations, immunochemistry features, and stress markers were compared between groups. RESULTS: The median tPO(2) level in synovial tissue indicated significant hypoxia (25.47 mm Hg). Higher frequency of mtDNA mutations was associated with reduced in vivo oxygen tension (P = 0.05) and with higher synovial 4-HNE cytoplasmic expression (P = 0.04). Synovial expression of CytcO II correlated with in vivo tPO(2) levels (P = 0.03), and levels were lower in patients with tPO(2) <20 mm Hg (P < 0.05). In vitro levels of mtDNA mutations, ROS, mitochondrial membrane potential, 8-oxo-dG, and 4-HNE were higher in synoviocytes exposed to 1% hypoxia (P < 0.05); all of these increased levels were rescued by SOD and DMOG and, with the exception of ROS, by NAC. CONCLUSION: These findings demonstrate that hypoxia-induced mitochondrial dysfunction drives

  13. Visceral white fat remodelling contributes to intermittent hypoxia-induced atherogenesis.

    Science.gov (United States)

    Poulain, Laureline; Thomas, Amandine; Rieusset, Jennifer; Casteilla, Louis; Levy, Patrick; Arnaud, Claire; Dematteis, Maurice

    2014-02-01

    Obstructive sleep apnoea is a highly prevalent disease characterised by repetitive upper airway collapse during sleep leading to intermittent hypoxia. Cardiometabolic complications of sleep apnoea have been mostly attributed to intermittent hypoxia. These consequences could be mediated through intermittent hypoxia-related alterations of the visceral white fat, as it is recognised for playing an important role in inflammation, atherogenesis and insulin resistance. Epididymal adipose tissue alterations were investigated in 20-week-old nonobese male apolipoprotein E-deficient mice exposed to intermittent hypoxia (inspiratory oxygen fraction 5-21%, 60-s cycle, 8 h · day(-1)) or air for 6 weeks. These adipose tissue alterations, as well as metabolic alterations and aortic atherosclerosis, were then assessed in lipectomised or sham-operated mice exposed to intermittent hypoxia or air for 6 weeks. Intermittent hypoxia induced morphological (shrunken adipocytes), functional (increased uncoupling protein-1 expression) and inflammatory (increased macrophage recruitment and secretion of interleukin-6 and tumour necrosis factor-α) remodelling of epididymal adipose tissue. Hypoxic mice presented more severe dyslipidaemia and atherosclerosis lesions and developed insulin resistance. Epididymal lipectomy attenuated both intermittent hypoxia-induced dyslipidaemia and atherogenesis, but did not improve insulin sensitivity. Our results confirmed that the dyslipidaemic and proatherogenic effects of intermittent hypoxia are partly mediated through morphological, functional and inflammatory remodelling of visceral white fat, regardless of obesity.

  14. Sodium hydrosulfide prevents hypoxia-induced pulmonary arterial hypertension in broilers.

    Science.gov (United States)

    Yang, Y; Zhang, B K; Liu, D; Nie, W; Yuan, J M; Wang, Z; Guo, Y M

    2012-01-01

    1. The aim of the study was to determine if H(2)S is involved in the development of hypoxia-induced pulmonary hypertension in broilers, a condition frequently observed in a variety of cardiac and pulmonary diseases. 2. Two-week-old broilers were reared under normoxic conditions or exposed to normobaric hypoxia (6 h/day) with tissue levels of H(2)S adjusted by administering sodium hydrosulfide (NaHS, 10 µmol/kg body weight/day). Mean pulmonary arterial pressure, right ventricular mass, plasma and tissue H(2)S levels, the expression of cystathionine-β-synthase (CSE) and vascular remodeling were determined at 35 d of age. 3. Exposure to hypoxia-induced pulmonary arterial hypertension was characterized by elevated pulmonary pressure, right ventricular hypertrophy and vascular remodeling. This was accompanied by decreased expression of CSE and decreased concentrations of plasma and tissue H(2)S. 4. Hypoxia-induced pulmonary hypertension was significantly reduced by administration of NaHS but this protective effect was largely abolished by D, L-propargylglycerine, an inhibitor of CSE. 5. The results indicate that H(2)S is involved in the development of hypoxia-induced pulmonary hypertension. Supplementing NaHS or H(2)S could be a strategy for reducing hypoxia-induced hypertension in broilers.

  15. The effect of insulin-loaded linear poly(ethylene glycol-brush-like poly(L-lysine block copolymer on renal ischemia/reperfusion-induced lung injury through downregulating hypoxia-inducible factor

    Directory of Open Access Journals (Sweden)

    Tong F

    2016-04-01

    Full Text Available Fei Tong, Xiangyuan Tang, Xin Li, Wenquan Xia, Daojun Liu Department of Chemistry, Medical College, Shantou University, Shantou, People’s Republic of China Abstract: The aim of this study was to observe the therapeutic effect of insulin-loaded linear poly(ethylene glycol-brush-like poly(L-lysine block copolymer poly(ethylene glycol-b-(poly(ethylenediamine L-glutamate-g-poly(L-lysine (PEG-b-(PELG-g-PLL on renal ischemia/reperfusion-induced lung injury through downregulating hypoxia-inducible factor (HIF as compared to free insulin. Sprague Dawley rats were pretreated with 30 U/kg insulin or insulin/PEG-b-(PELG-g-PLL complex, and then subjected to 45 minutes of ischemia and 24 hours of reperfusion. The blood and lungs were collected, the level of serum creatinine and blood urea nitrogen were measured, and the dry/wet lung ratios, the activity of superoxide dismutase and myeloperoxidase, the content of methane dicarboxylic aldehyde and tumor necrosis factor-α, and the expression of HIF-1α and vascular endothelial growth factor (VEGF were measured in pulmonary tissues. Both insulin and insulin/PEG-b-(PELG-g-PLL preconditioning improved the recovery of renal function, reduced pulmonary oxidative stress injury, restrained inflammatory damage, and downregulated the expression of HIF-1α and VEGF as compared to ischemia/reperfusion group, while insulin/PEG-b-(PELG-g-PLL significantly improved this effect. Keywords: insulin, block copolymer, RI/RILI, HIF-1α, VEGF

  16. Expression and Function of Hypoxia Inducible Factor-1α and Vascular Endothelial Growth Factor in Pulp Tissue of Teeth under Orthodontic Movement

    Directory of Open Access Journals (Sweden)

    Fulan Wei

    2015-01-01

    Full Text Available Orthodontic force may lead to cell damage, circulatory disturbances, and vascular changes of the dental pulp, which make a hypoxic environment in pulp. In order to maintain the homeostasis of dental pulp, hypoxia will inevitably induce the defensive reaction. However, this is a complex process and is regulated by numerous factors. In this study, we established an experimental animal model of orthodontic tooth movement to investigate the effects of mechanical force on the expression of VEGF and HIF-1α in dental pulp. Histological analysis of dental pulp and expressions of HIF-1α and VEGF proteins in dental pulp were examined. The results showed that inflammation and vascular changes happened in dental pulp tissue in different periods. Additionally, there were significant changes in the expression of HIF-1α and VEGF proteins under orthodontic force. After application of mechanical load, expression of HIF-1α and VEGF was markedly positive in 1, 3, 7 d, and 2 w groups, and then it weakened in 4 w group. These findings suggested that the expression of HIF-1α and VEGF was enhanced by mechanical force. HIF-1α and VEGF may play an important role in retaining the homeostasis of dental pulp during orthodontic tooth movement.

  17. The association of genetic polymorphisms of hypoxia inducible factor-1 alpha and vascular endothelial growth factor with increased risk of chronic obstructive pulmonary disease: A case-control study.

    Science.gov (United States)

    Yu, Zhen-Gang; Wang, Bing-Zhe; Cheng, Zhao-Zhong

    2017-09-01

    Accumulated data over the years have suggested that hypoxia inducible factor-1 alpha (HIF-1α) and its downstream vascular endothelial growth factor (VEGF) gene may be linked with chronic obstructive pulmonary disease (COPD). This study aims to investigate the association of HIF-1α and VEGF genetic polymorphisms and their correlated risks with COPD. COPD patients (case group) and healthy individuals (control group) were recruited. DNA was extracted to detect HIF-1α and VEGF genetic polymorphisms. Basal lung volume and forced expiratory capacity in 1st second (FEV1)/forced vital capacity (FVC) and FEV1/predicted value (pred)% were calculated. Genotype and allele distributions in HIF-1α and VEGF genes were analyzed. Kaplan-Meier curves and logistic regression model were used for analysis of survival and COPD risk factors. Haplotypes for HIF-1α rs11549465 and rs11549467 were analyzed. FEV1/FVC and FEV1/pred% in the case group were lower than the control group. Frequencies of HIF-1α rs11549465 CT + TT genotype and T allele, and rs11549467 GA + AA genotype and A allele were higher in the case group than the control group. Patients with rs11549465 CT + TT had higher COPD risk than those with the CC genotype. Patients with rs11549467 GA + AA showed higher COPD risk and lower FEV1/FVC and FEV1/pred% than those with the GG genotype. Patients with HIF-1α TA haplotype showed higher COPD risk than those with the CG haplotype. Survival rate of patients with HIF-1α rs11549467 GG genotype was higher than those with the GA + AA genotype. HIF-1α rs11549467 polymorphism may be associated with COPD risk. Copyright © 2017. Published by Elsevier Taiwan.

  18. Novel Pathway for Hypoxia-Induced Proliferation and Migration in Human Mesenchymal Stem Cells: Involvement of HIF-1α, FASN, and mTORC1.

    Science.gov (United States)

    Lee, Hyun Jik; Ryu, Jung Min; Jung, Young Hyun; Oh, Sang Yub; Lee, Sei-Jung; Han, Ho Jae

    2015-07-01

    The control of stem cells by oxygen signaling is an important way to improve various stem cell physiological functions and metabolic nutrient alteration. Lipid metabolism alteration via hypoxia is thought to be a key factor in controlling stem cell fate and function. However, the interaction between hypoxia and the metabolic and functional changes to stem cells is incompletely described. This study aimed to identify hypoxia-inducible lipid metabolic enzymes that can regulate umbilical cord blood (UCB)-derived human mesenchymal stem cell (hMSC) proliferation and migration and to demonstrate the signaling pathway that controls functional change in UCB-hMSCs. Our results indicate that hypoxia treatment stimulates UCB-hMSC proliferation, and expression of two lipogenic enzymes: fatty acid synthase (FASN) and stearoyl-CoA desaturase-1 (SCD1). FASN but not SCD1 is a key enzyme for regulation of UCB-hMSC proliferation and migration. Hypoxia-induced FASN expression was controlled by the hypoxia-inducible factor-1 alpha (HIF-1α)/SCAP/SREBP1 pathway. Mammalian target of rapamycin (mTOR) was phosphorylated by hypoxia, whereas inhibition of FASN by cerulenin suppressed hypoxia-induced mTOR phosphorylation as well as UCB-hMSC proliferation and migration. RAPTOR small interfering RNA transfection significantly inhibited hypoxia-induced proliferation and migration. Hypoxia-induced mTOR also regulated CDK2, CDK4, cyclin D1, cyclin E, and F-actin expression as well as that of c-myc, p-cofilin, profilin, and Rho GTPase. Taken together, the results suggest that mTORC1 mainly regulates UCB-hMSC proliferation and migration under hypoxia conditions via control of cell cycle and F-actin organization modulating factors. In conclusion, the HIF-1α/FASN/mTORC1 axis is a key pathway linking hypoxia-induced lipid metabolism with proliferation and migration in UCB-hMSCs. Stem Cells 2015;33:2182-2195.

  19. Hypoxia-inducible factor-1α and small ubiquitin-related modifier%缺氧诱导因子-1与小泛素相关修饰物

    Institute of Scientific and Technical Information of China (English)

    张莉; 屈艺; 母得志

    2010-01-01

    缺氧诱导因子-1(hypoxia inducible factor-1,HIF-1)是机体氧平衡调节的重要转录因子,由α和β两种亚基组成,受氧分压调节的HIF-1α在蛋白质翻译后水平被多种方式修饰,如泛素化、磷酸化、羟基化、乙酰化、糖基化等,从而影响其蛋白稳定性、核转位以及对靶基因的转录调节等.小泛素相关修饰物(small ubiquitin-related modifier,SUMO)是一种参与真核生物可逆性蛋白质翻译后修饰的小分子蛋白,结构与泛素相似.SUMO化和去SUMO化修饰参与许多生物学过程的调节,包括细胞信号传导、转录调控、细胞周期进程及生物节律等.SUMO化修饰与低氧条件下HIF-1α的稳定性和转录活性相关,为了解HIF-1α的自身调控机制提供了新思路.%Hypoxia-inducible factor-1 (HIF-1) is a key transciptional regulator of cellular and systemic oxygen homeostasis,composed of the two subunits,HIF-1α and HIF-1β.HIF-1α is an inducible subunit regulated by hypoxia,which is posttranslationally modified by various ways,including ubiquitination,phosphorylation,hydroxylation,acetylation and glycation,accordingly affecting its protein's stability,nuclear translocation and regulation of its target genes.Small ubiquitin-related modifier (SUMO) is an micromolecule protein participating in posttranslational modifications of proteins dynamicly in eukaryotic organism,which is similar in structure to ubiquitin.SUMOylation and deSUMOylation are involved in multiple regulations of biologic processes,such as signal transduction,transcriptional regulation,cell cycle processes and biological rhythm.SUMOylation is related to HIF-1α stability and transcription activity in hypoxia,providing a newthread to study self-regulation mechanism of HIF-1α for us.

  20. EP1 Prostanoid Receptor Coupling to Gi/o Up-Regulates the Expression of Hypoxia-Inducible Factor-1α through Activation of a Phosphoinositide-3 Kinase Signaling Pathway

    Science.gov (United States)

    Ji, Ruyue; Chou, Chih-Ling; Xu, Wei; Chen, Xiao-Bo; Woodward, David F.

    2010-01-01

    The EP1 prostanoid receptor is one of four subtypes whose cognate physiological ligand is prostaglandin-E2 (PGE2). It is in the family of G-protein-coupled receptors and is known to activate Ca2+ signaling, although relatively little is known about other aspects of E-type prostanoid receptor (EP) 1 receptor signaling. In human embryonic kidney (HEK) cells expressing human EP1 receptors, we now show that PGE2 stimulation of the EP1 receptor up-regulates the expression of hypoxia-inducible factor-1α (HIF-1α), which can be completely blocked by pertussis toxin, indicating coupling to Gi/o. This up-regulation of HIF-1α occurs under normoxic conditions and could be inhibited with wortmannin, Akt inhibitor, and rapamycin, consistent with the activation of a phosphoinositide-3 kinase/Akt/mammalian target of rapamycin (mTOR) signaling pathway, respectively. In contrast to the hypoxia-induced up-regulation of HIF-1α, which involves decreased protein degradation, the up-regulation of HIF-1α by the EP1 receptor was associated with the phosphorylation of ribosomal protein S6 (rpS6), suggesting activation of the ribosomal S6 kinases and increased translation. Stimulation of endogenous EP1 receptors in human HepG2 hepatocellular carcinoma cells recapitulated the normoxic up-regulation of HIF-1α observed in HEK cells, was sensitive to pertussis toxin, and involved the activation of mTOR signaling and phosphorylation of rpS6. In addition, treatment of HepG2 cells with sulprostone, an EP1-selective agonist, up-regulated the mRNA expression of vascular endothelial growth factor-C, a HIF-regulated gene. HIF-1α is known to promote tumor growth and metastasis and is often up-regulated in cancer. Our findings provide a potential mechanism by which increased PGE2 biosynthesis could up-regulate the expression of HIF-1α and promote tumorigenesis. PMID:20335389

  1. Ets-1 as an early response gene against hypoxia-induced apoptosis in pancreatic β-cells.

    Science.gov (United States)

    Qiao, N; Xu, C; Zhu, Y-X; Cao, Y; Liu, D-C; Han, X

    2015-02-19

    Hypoxia complicates islet isolation for transplantation and may contribute to pancreatic β-cell failure in type 2 diabetes. Pancreatic β-cells are susceptible to hypoxia-induced apoptosis. Severe hypoxic conditions during the immediate post-transplantation period are a main non-immune factor leading to β-cell death and islet graft failure. In this study, we identified the transcription factor Ets-1 (v-ets erythroblastosis virus E26 oncogene homolog 1) as an early response gene against hypoxia-induced apoptosis in pancreatic β-cells. Hypoxia regulates Ets-1 at multiple levels according to the degree of β-cell oxygen deprivation. Moderate hypoxia promotes Ets-1 gene transcription, whereas severe hypoxia promotes its transactivation activity, as well as its ubiquitin-proteasome mediated degradation. This degradation causes a relative insufficiency of Ets-1 activity, and limits the transactivation effect of Ets-1 on downstream hypoxic-inducible genes and its anti-apoptotic function. Overexpression of ectopic Ets-1 in MIN6 and INS-1 cells protects them from severe hypoxia-induced apoptosis in a mitochondria-dependent manner, confirming that a sufficient amount of Ets-1 activity is critical for protection of pancreatic β-cells against hypoxic injury. Targeting Ets-1 expression may be a useful strategy for islet graft protection during the immediate post-transplantation period.

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

    Science.gov (United States)

    Kraus, Richard J; Yu, Xianming; Cordes, Blue-Leaf A; Sathiamoorthi, Saraniya; Iempridee, Tawin; Nawandar, Dhananjay M; Ma, Shidong; Romero-Masters, James C; McChesney, Kyle G; Lin, Zhen; Makielski, Kathleen R; Lee, Denis L; Lambert, Paul F; Johannsen, Eric C; Kenney, Shannon C; Mertz, Janet E

    2017-06-01

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

  3. Suppression of Akt-HIF-1α signaling axis by diacetyl atractylodiol inhibits hypoxia-induced angiogenesis

    Science.gov (United States)

    Choi, Sik-Won; Lee, Kwang-Sik; Lee, Jin Hwan; Kang, Hyeon Jung; Lee, Mi Ja; Kim, Hyun Young; Park, Kie-In; Kim, Sun-Lim; Shin, Hye Kyoung; Seo, Woo Duck

    2016-01-01

    Hypoxia-inducible factor (HIF)-1α is a key regulator associated with tumorigenesis, angiogenesis, and metastasis. HIF-1α regulation under hypoxia has been highlighted as a promising therapeutic target in angiogenesis-related diseases. Here, we demonstrate that diacetyl atractylodiol (DAA) from Atractylodes japonica (A. japonica) is a potent HIF-1α inhibitor that inhibits the Akt signaling pathway. DAA dose-dependently inhibited hypoxia-induced HIF-1α and downregulated Akt signaling without affecting the stability of HIF-1α protein. Furthermore, DAA prevented hypoxia-mediated angiogenesis based on in vitro tube formation and in vivo chorioallantoic membrane (CAM) assays. Therefore, DAA might be useful for treatment of hypoxia-related tumorigenesis, including angiogenesis. [BMB Reports 2016; 49(9): 508-513] PMID:27439603

  4. Hypoxia induced expression of endogenous markers in vitro is highly influenced by pH

    DEFF Research Database (Denmark)

    Sørensen, Brita Singers; Alsner, Jan; Overgaard, Jens

    2007-01-01

    BACKGROUND: Genes such as carbonic anhydrase IX (Ca9), glucose transporter 1 (Glut1), lactate dehydrogenase A (LDH-A), osteopontin (OPN) and lysyl oxidase (LOX) have been suggested as hypoxic markers, but inconsistent results suggest that factors other than oxygen influence their expression......Ha and FaDu(DD) cells Ca9 and LOX reached the highest level of expression at 1% oxygen. In FaDu(DD) cells, a pH of 6.5 had a medium suppression effect on the hypoxia induced expression of Ca9. pH 6.3 resulted in severe suppression of expression for Ca9 and LOX in both SiHa and FaDu(DD). Glut1 and LDH-A had...

  5. Hypoxia induced expression of endogenous markers in vitro is highly influenced by pH

    DEFF Research Database (Denmark)

    Sørensen, Brita Singers; Alsner, Jan; Overgaard, Jens;

    2007-01-01

    BACKGROUND: Genes such as carbonic anhydrase IX (Ca9), glucose transporter 1 (Glut1), lactate dehydrogenase A (LDH-A), osteopontin (OPN) and lysyl oxidase (LOX) have been suggested as hypoxic markers, but inconsistent results suggest that factors other than oxygen influence their expression......Ha and FaDu(DD) cells Ca9 and LOX reached the highest level of expression at 1% oxygen. In FaDu(DD) cells, a pH of 6.5 had a medium suppression effect on the hypoxia induced expression of Ca9. pH 6.3 resulted in severe suppression of expression for Ca9 and LOX in both SiHa and FaDu(DD). Glut1 and LDH-A had...

  6. Relationship between hypoxia inducible factor-1 and hypoxic lung injury%低氧诱导因子1与低氧性肺损伤的研究进展

    Institute of Scientific and Technical Information of China (English)

    蒋云燕; 谢敏

    2009-01-01

    Hypoxia inducible factor-1(HIF-1)is a nucleoprotein with transcriptional activity produced by cells under hypoxic condition,which plays a crucial role in cellular response to stress of hypoxia.HIF-1 modulates the expression of more than 100 genes involved in cellular adaptation and survival under hypoxic stress.In recent years,more attention has been paid to the role of HIF-1 in hypoxic lung injury.This article makes a summary on the biological characteristics of HIF-1 and adjustment to the target genes and its effect on hypoxic lung injury.%低氧诱导因子1是细胞在低氧条件下产生的具有转录活性的核蛋白,在低氧应答反应中起核心作用,能调节100多种涉及低氧应激下细胞适应和存活的靶基因.近年来,低氧诱导因子1在低氧性肺损伤中的作用也逐渐受到人们的关注.该文就低氧诱导因子1的生物学特点、对靶基因的调节及在低氧性肺损伤中的作用作一综述.

  7. Chronic intermittent hypoxia increases β cell mass and activates the mammalian target of rapamycin/hypoxia inducible factor 1/vascular endothelial growth factor A pathway in mice pancreatic islet

    Institute of Scientific and Technical Information of China (English)

    GU Chen-juan; LI Min; LI Qing-yun; LI Ning

    2013-01-01

    Background Growing evidence from population and clinic based studies showed that obstructive sleep apnea (OSA) and its characterizing chronic intermittent hypoxia (IH) were independently associated with the development of type 2 diabetes mellitus.However,the pathogenesis by which OSA induces glucose metabolic disorders is not clear.We determined changes in pancreatic β cell mass and the mammalian target of rapamycin (mTOR)/hypoxia inducible factor 1 (HIF-1)/ vascular endothelial growth factor A (VEGF-A) pathway following IH exposure.Methods A controlled gas delivery system regulated the flow of nitrogen and oxygen into a customized cage housing mice during the experiment.Twenty-four male wild C57BL/6J mice were either exposed to IH (n=12) or intermittent air as a control (n=12) for 56 days.Mice were anaesthetized and sacrificed after exposure,pancreas samples were dissected for immunofluorescent staining.Insulin and DAPI staining labelled islet β cells.Insulin positive area and β cell number per islet were measured.P-S6,HIF-1α and VEGF-A staining were performed to detect the activation of mTOR/HIF-1NEGF-A pathway.Results After eight weeks of IH exposure,insulin positive area increased by an average of 18.5% (P <0.05).The β cell number per islet increased (92 vs.55,respectively for IH and the control groups,P <0.05) with no change in the size of individual β cells.Islet expression of HIF-1α and VEGF-A were higher in IH group than control group,and percentage of p-S6 positive β cell also increased after IH exposure (16.8% vs.4.6% respectively for IH and the control groups,P <0.05).Conclusion The number of pancreatic β cells increased as did the activity of the mTOR/HIF-1NEGF-A pathway after exposure to IH.

  8. Oroxylin A inhibits hypoxia-induced invasion and migration of MCF-7 cells by suppressing the Notch pathway.

    Science.gov (United States)

    Cheng, Yao; Zhao, Kai; Li, Guojun; Yao, Jing; Dai, Qinsheng; Hui, Hui; Li, Zhiyu; Guo, Qinglong; Lu, Na

    2014-08-01

    Tumor invasion and migration obstructs the treatment and prognosis of cancer. In this research, we investigated the effect of oroxylin A, a natural compound extracted from Scutellaria radix, the root of Scutellaria baicalensis, on inhibition of the invasion and migration of three different tumor cell lines: MCF-7, DU145, and HepG2. The results suggested that oroxylin A could inhibit hypoxia-induced migration and invasion of the three cell lines mentioned above. To study the detailed mechanisms, studies were carried out on MCF-7 cells and it was found that oroxylin A could regulate the expression of related markers in MCF-7 cells including E-cadherin, N-cadherin, and Vimentin. It was also found that oroxylin A inhibited the hypoxia-induced invasion and migration of MCF-7 cells by suppressing the Notch pathway. Oroxylin A inhibited N1ICD translocating to the nucleus and binding to epithelial-mesenchymal transition-related transcription factor Snail, thus suppressing the invasion and migration of MCF-7 cells. Therefore, oroxylin A is expected to be a promising candidate for antimetastasis treatment through suppression of the hypoxia-induced Notch pathway.

  9. Salidroside attenuates chronic hypoxia-induced pulmonary hypertension via adenosine A2a receptor related mitochondria-dependent apoptosis pathway.

    Science.gov (United States)

    Huang, Xiaoying; Zou, Lizhen; Yu, Xiaoming; Chen, Mayun; Guo, Rui; Cai, Hui; Yao, Dan; Xu, Xiaomei; Chen, Yanfan; Ding, Cheng; Cai, Xueding; Wang, Liangxing

    2015-05-01

    Pulmonary arterial hypertension (PAH) is characterized by pulmonary arterial remodeling mainly due to excess cellular proliferation and apoptosis resistance of pulmonary arterial smooth muscle cells (PASMCs). Salidroside, an active ingredient isolated from Rhodiola rosea is proposed to exert protective effects against PAH. However, the function of salidroside in PAH has not been investigated systematically and the underlying mechanisms are not clear. To investigate the effects of salidroside on PAH, the mice in chronic hypoxia model of PAH were given by an increasing concentration of salidroside (0, 16 mg/kg, 32 mg/kg, and 64 mg/kg). After salidroside treatment, the chronic hypoxia-induced right ventricular hypertrophy and pulmonary arterial remodeling were attenuated, suggesting a protective role played by salidroside in PAH. To explore the potential mechanisms, the apoptosis of PASMCs after salidroside treatment under hypoxia conditions were determined in vivo and in vitro, and also the mitochondria-dependent apoptosis factors, Bax, Bcl-2, cytochrome C, and caspase 9 were examined. The results revealed that salidroside reversed hypoxia-induced cell apoptosis resistance at least partially via a mitochondria-dependent pathway. In addition, salidroside upregulated the expression of adenosine A2a receptor (A2aR) in lung tissues of mice and in PASMCs in vitro after hypoxia exposure. Combined the evidence above, we conclude that salidroside can attenuate chronic hypoxia-induced PAH by promoting PASMCs apoptosis via an A2aR related mitochondria dependent pathway. Copyright © 2015. Published by Elsevier Ltd.

  10. Differential roles of prostaglandin E-type receptors in activation of hypoxia-inducible factor 1 by prostaglandin E1 in vascular-derived cells under non-hypoxic conditions

    Directory of Open Access Journals (Sweden)

    Kengo Suzuki

    2013-11-01

    Full Text Available Prostaglandin E1 (PGE1, known pharmaceutically as alprostadil, has vasodilatory properties and is used widely in various clinical settings. In addition to acute vasodilatory properties, PGE1 may exert beneficial effects by altering protein expression of vascular cells. PGE1 is reported to be a potent stimulator of angiogenesis via upregulation of VEGF expression, which is under the control of the transcription factor hypoxia-inducible factor 1 (HIF-1. However, the molecular mechanisms behind the phenomenon are largely unknown. In the present study, we investigated the mechanism by which PGE1 induces HIF-1 activation and VEGF gene expression in human aortic smooth muscle cells (HASMCs and human umbilical vein endothelial cells (HUVECs, both vascular-derived cells. HUVECs and HASMCs were treated with PGE1 at clinically relevant concentrations under 20% O2 conditions and HIF-1 protein expression was investigated. Expression of HIF- 1α protein and the HIF-1-downstream genes were low under 20% O2 conditions and increased in response to PGE1 treatment in both HUVECs and HASMCs in a dose- and time-dependent manner under 20% O2 conditions as comparable to exposure to 1% O2 conditions. Studies using EP-receptor-specific agonists and antagonists revealed that EP1 and EP3 are critical to PGE1-induced HIF-1 activation. In vitro vascular permeability assays using HUVECs indicated that PGE1 increased vascular permeability in HUVECs. Thus, we demonstrate that PGE1 induces HIF- 1α protein expression and HIF-1 activation under non-hypoxic conditions and also provide evidence that the activity of multiple signal transduction pathways downstream of EP1 and EP3 receptors is required for HIF-1 activation.

  11. Paeoniflorin prevents hypoxia-induced epithelial–mesenchymal transition in human breast cancer cells

    Directory of Open Access Journals (Sweden)

    Zhou Z

    2016-04-01

    Full Text Available Zhenyu Zhou,1,* Shunchang Wang,1,* Caijuan Song,2 Zhuang Hu11Department of Thyroid and Breast, Huaihe Hospital, Henan University, Kaifeng, 2Department of Immunization Program, Zhengzhou Center for Disease Control and Prevention, Zhengzhou, People’s Republic of China*These authors contributed equally to this workAbstract: Paeoniflorin (PF is a monoterpene glycoside extracted from the root of Paeonia lactiflora Pall. Previous studies have demonstrated that PF inhibits the growth, invasion, and metastasis of tumors in vivo and in vitro. However, the effect of PF on hypoxia-induced epithelial–mesenchymal transition (EMT in breast cancer cells remains unknown. Therefore, the objective of this study was to investigate the effect of PF on hypoxia-induced EMT in breast cancer cells, as well as characterize the underlying mechanism. The results presented in this study demonstrate that PF blocks the migration and invasion of breast cancer cells by repressing EMT under hypoxic conditions. PF also significantly attenuated the hypoxia-induced increase in HIF-1α level. Furthermore, PF prevented hypoxia-induced expression of phosphorylated PI3K and Akt in MDA-MB-231 cells. In conclusion, PF prevented hypoxia-induced EMT in breast cancer cells by inhibiting HIF-1α expression via modulation of PI3K/Akt signaling pathway. This finding provides evidence that PF can serve as a therapeutic agent for the treatment of breast cancer.Keywords: paeoniflorin, breast cancer, hypoxia, epithelial–mesenchymal transition, PI3K/Akt signaling pathway

  12. Intermittent hypoxia induces the proliferation of rat vascular smooth muscle cell with the increases in epidermal growth factor family and erbB2 receptor

    Energy Technology Data Exchange (ETDEWEB)

    Kyotani, Yoji, E-mail: cd147@naramed-u.ac.jp [Department of Pharmacology, Nara Medical University School of Medicine, Kashihara 634-8521 (Japan); Department of Pharmacy, Nara Medical University Hospital, Kashihara 634-8522 (Japan); Ota, Hiroyo [Second Department of Internal Medicine, Nara Medical University School of Medicine, Kashihara 634-8522 (Japan); Department of Biochemistry, Nara Medical University School of Medicine, Kashihara 634-8521 (Japan); Itaya-Hironaka, Asako; Yamauchi, Akiyo; Sakuramoto-Tsuchida, Sumiyo [Department of Biochemistry, Nara Medical University School of Medicine, Kashihara 634-8521 (Japan); Zhao, Jing; Ozawa, Kentaro; Nagayama, Kosuke; Ito, Satoyasu [Department of Pharmacology, Nara Medical University School of Medicine, Kashihara 634-8521 (Japan); Takasawa, Shin [Department of Biochemistry, Nara Medical University School of Medicine, Kashihara 634-8521 (Japan); Kimura, Hiroshi [Second Department of Internal Medicine, Nara Medical University School of Medicine, Kashihara 634-8522 (Japan); Uno, Masayuki [Department of Pharmacy, Nara Medical University Hospital, Kashihara 634-8522 (Japan); Yoshizumi, Masanori [Department of Pharmacology, Nara Medical University School of Medicine, Kashihara 634-8521 (Japan)

    2013-11-15

    Obstructive sleep apnea is characterized by intermittent hypoxia (IH), and associated with cardiovascular diseases, such as stroke and heart failure. These cardiovascular diseases have a relation to atherosclerosis marked by the proliferation of vascular smooth muscle cells (VSMCs). In this study, we investigated the influence of IH on cultured rat aortic smooth muscle cell (RASMC). The proliferation of RASMC was significantly increased by IH without changing the level of apoptosis. In order to see what induces RASMC proliferation, we investigated the influence of normoxia (N)-, IH- and sustained hypoxia (SH)-treated cell conditioned media on RASMC proliferation. IH-treated cell conditioned medium significantly increased RASMC proliferation compared with N-treated cell conditioned medium, but SH-treated cell conditioned medium did not. We next investigated the epidermal growth factor (EGF) family as autocrine growth factors. Among the EGF family, we found significant increases in mRNAs for epiregulin (ER), amphiregulin (AR) and neuregulin-1 (NRG1) in IH-treated cells and mature ER in IH-treated cell conditioned medium. We next investigated the changes in erbB family receptors that are receptors for ER, AR and NRG1, and found that erbB2 receptor mRNA and protein expressions were increased by IH, but not by SH. Phosphorylation of erbB2 receptor at Tyr-1248 that mediates intracellular signaling for several physiological effects including cell proliferation was increased by IH, but not by SH. In addition, inhibitor for erbB2 receptor suppressed IH-induced cell proliferation. These results provide the first demonstration that IH induces VSMC proliferation, and suggest that EGF family, such as ER, AR and NRG1, and erbB2 receptor could be involved in the IH-induced VSMC proliferation. - Highlights: ●In vitro system for intermittent hypoxia (IH) and sustained hypoxia (SH). ●IH, but not SH, induces the proliferation of rat vascular smooth muscle cell. ●Epiregulin m

  13. Hypoxia-inducible Factor-1α mRNA Contains an Internal Ribosome Entry Site That Allows Efficient Translation during Normoxia and Hypoxia

    OpenAIRE

    Lang, Kenneth J. D.; Kappel, Andreas; Gregory J. Goodall

    2002-01-01

    HIF-1α is the regulated subunit of the HIF-1 transcription factor, which induces transcription of a number of genes involved in the cellular response to hypoxia. The HIF-1α protein is rapidly degraded in cells supplied with adequate oxygen but is stabilized in hypoxic cells. Using polysome profile analysis, we found that translation of HIF-1α mRNA in NIH3T3 cells is spared the general reduction in translation rate that occurs during hypoxia. To assess whether the 5′UTR of the HIF-1α mRNA cont...

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

    Directory of Open Access Journals (Sweden)

    Alessio Paone

    2010-07-01

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

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

    Science.gov (United States)

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

    2010-06-01

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

  16. A Chemokine Receptor, CXCR4, Which Is Regulated by Hypoxia-Inducible Factor 2α, Is Crucial for Functional Endothelial Progenitor Cells Migration to Ischemic Tissue and Wound Repair

    Science.gov (United States)

    Tu, Tran Cam; Nagano, Masumi; Yamashita, Toshiharu; Hamada, Hiromi; Ohneda, Kinuko; Kimura, Kenichi

    2016-01-01

    Endothelial progenitor cells (EPCs) have the ability to form new blood vessels and protect ischemic tissues from damage. We previously reported that EPCs with low activity of aldehyde dehydrogenase (Alde-Low EPCs) possess the greater ability to treat ischemic tissues compared with Alde-High EPCs. The expression level of the hypoxia-inducible factors (HIFs), HIF-1α and HIF-2α, was found to be greater in Alde-Low EPCs than in Alde-High EPCs. However, the precise role of the HIF factors in the regulation of EPC activity remains obscure. In this study, we demonstrate a critical role of HIF-2α and its target gene CXCR4 for controlling the migratory activity of EPC to ischemic tissue. We found that coculture of Alde-High EPCs with microvesicles derived from Alde-Low EPCs improved their ability to repair an ischemic skin flap, and the expression of CXCR4 and its ligand SDF1 was significantly increased following the coculture. In Alde-Low EPCs, the expression of CXCR4 was suppressed by short hairpin RNA (shRNA)-mediated HIF-2α, but not HIF-1α downregulation. Chromatin immunoprecipitation assays showed that HIF-2α, but not HIF-1α, binds to the promoter region of CXCR4 gene. The CXCR4 shRNA treatment in Alde-Low EPCs almost completely abrogated their migratory activity to ischemic tissues, whereas the reduction of vascular endothelial growth factor (VEGF) showed much less effect. The CXCR4 overexpression in Alde-High EPCs resulted in a partial, but significant improvement in their repairing ability in an ischemic skin flap. Collectively, these findings indicate that the CXCR4/SDF-1 axis, which is specifically regulated by HIF-2α, plays a crucial role in the regulation of EPC migration to ischemic tissues. PMID:26620723

  17. Simulating Sleep Apnea by Exposure to Intermittent Hypoxia Induces Inflammation in the Lung and Liver

    Directory of Open Access Journals (Sweden)

    Darlan Pase da Rosa

    2012-01-01

    Full Text Available Sleep apnea is a breathing disorder that results from momentary and cyclic collapse of the upper airway, leading to intermittent hypoxia (IH. IH can lead to the formation of free radicals that increase oxidative stress, and this mechanism may explain the association between central sleep apnea and nonalcoholic steatohepatitis. We assessed the level of inflammation in the lung and liver tissue from animals subjected to intermittent hypoxia and simulated sleep apnea. A total of 12 C57BL/6 mice were divided into two groups and then exposed to IH (n=6 or a simulated IH (SIH (n=6 for 35 days. We observed an increase in oxidative damage and other changes to endogenous antioxidant enzymes in mice exposed to IH. Specifically, the expression of multiple transcription factors, including hypoxia inducible factor (HIF-1α, nuclear factor kappa B (NF-κB, and tumor necrosis factor (TNF-α, inducible NO synthase (iNOS, vascular endothelial growth factor (VEGF, and cleaved caspase 3 were shown to be increased in the IH group. Overall, we found that exposure to intermittent hypoxia for 35 days by simulating sleep apnea leads to oxidative stress, inflammation, and increased activity of caspase 3 in the liver and lung.

  18. Gene transcripts encoding hypoxia-inducible factor (HIF) exhibit tissue- and muscle fiber type-dependent responses to hypoxia and hypercapnic hypoxia in the Atlantic blue crab, Callinectes sapidus.

    Science.gov (United States)

    Hardy, Kristin M; Follett, Chandler R; Burnett, Louis E; Lema, Sean C

    2012-09-01

    Hypoxia inducible factor (HIF) is a transcription factor that under low environmental oxygen regulates the expression of suites of genes involved in metabolism, angiogenesis, erythropoiesis, immune function, and growth. Here, we isolated and sequenced partial cDNAs encoding hif-α and arnt/hif-β from the Atlantic blue crab, Callinectes sapidus, an estuarine species that frequently encounters concurrent hypoxia (low O(2)) and hypercapnia (elevated CO(2)). We then examined the effects of acute exposure (1h) to hypoxia (H) and hypercapnic hypoxia (HH) on relative transcript abundance for hif-α and arnt/hif-β in different tissues (glycolytic muscle, oxidative muscle, hepatopancreas, gill, and gonads) using quantitative real-time RT-PCR. Our results indicate that hif-α and arnt/hif-β mRNAs were constitutively present under well-aerated normoxia (N) conditions in all tissues examined. Further, H and HH exposure resulted in both tissue-specific and muscle fiber type-specific effects on relative hif-α transcript abundance. In the gill and glycolytic muscle, relative hif-α mRNA levels were significantly lower under H and HH, compared to N, while no change (or a slight increase) was detected in oxidative muscle, hepatopancreas and gonadal tissues. H and HH did not affect relative transcript abundance for arnt/hif-β in any tissue or muscle fiber type. Thus, in crustaceans the HIF response to H and HH appears to involve changes in hif transcript abundance, with variation in hif-α and arnt/hif-β transcriptional dynamics occurring in both a tissue- and muscle fiber type-dependent manner. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. [Protective effect of salidroside against high altitude hypoxia-induced brain injury in rats].

    Science.gov (United States)

    Dong, Xiaoru; Zhang, Xiangnan; Li, Dan; Li, Bin; Wang, Jiye; Meng, Shanshan; Luo, Wenjing; Zhang, Wenbin

    2015-10-01

    To observe the protective effect of salidroside against brain injury in rats exposed to hypobaric hypoxia, and investigate the molecular mechanism of salidroside in the prevention of hypobaric hypoxia-induced brain injury. Rats were placed in experiment module simulating 6000 m altitude to establish acute hypobaric hypoxia-induced brain injury models. Their respiratory frequency was observed and recorded. Cell apoptosis in the hippocampal dentate gyrus (DG) was detected by TUNEL assay; the expressions of Ras homolog family member A (RhoA), phosphorylated extracellular signal-regulated kinase (p-ERK) and phosphorylated c-Jun N-terminal kinase (p-JNK) were detected by Western blotting. After acute exposure to 6000 m altitude, the respiratory frequency of the rats increased remarkably. The simulation of hypobaric hypoxia induced cell apoptosis in hippocampal DG region, and salidroside intervention inhibited the process of cell apoptosis. The expressions of RhoA, p-ERK, p-JNK decreased after hypobaric hypoxia exposure. Salidroside intervention reversed RhoA expression and raised the levels of p-ERK and p-JNK. Acute exposure to hypobaric hypoxia can induce cell apoptosis in rat hippocampal DG, and salidroside can protect the cells from the exposure-induced apoptosis.

  20. [Cell apoptosis and expression of hypoxia-inducible transcription factor-1 alpha in kidney tissue after severe burn with delayed fluid resuscitation in rats in areas of different altitude].

    Science.gov (United States)

    Jiang, Jiang; Liu, Yi; Zhang, Shi-fan; Cai, Qian; Zhang, Xian-ying; Zhang, Bin; Xiao, Bin

    2008-07-01

    To explore the relationship of cell apoptosis and expression regularity of hypoxia-inducible transcription factor (HIF)-1 alpha after severe burn with delayed fluid resuscitation in areas of different altitude. A total of 240 male Wistar rats, which were raised in areas of different altitude (1,517 and 3,840 meters), were employed as the experimental models [They received a 30% total body surface area (TBSA)III degree scald injury], and then they were randomly divided into 3 groups: delayed fluid resuscitation group (DFR, n=50), immediate fluid resuscitation group (IFR, n=60) and control group (CG, n=10). Renal tissue samples were harvested at 1, 6, 12, 24, 72 and 168 hours after burn, respectively. Cell apoptosis was detected by tissue chip technology and terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling (TUNEL). The expression of HIF-1 alpha was assessed by immunohistochemistry and image analysis. With increase in altitude, cellular edema, degeneration, necrosis and disintegration of renal tissue were gradually worsening, the capillaries of renal glomeruli became dilated and engorged, with degeneration and necrosis of endothelial cells, engorgement and edema of renal interstitium, and infiltration of inflammatory cells. Pathological changes in DFR group were more serious than that of IFR group. Cell apoptosis and the expression of HIF-1 alpha were both enhanced, the latter mainly appeared in nuclei of renal cells, and they were more marked at 3,840 meters compared with those at 1,517 meters. They were more marked in experimental groups than in control group, especially so in DFR group (Pkidney cell apoptosis.

  1. Regulatory systems for hypoxia-inducible gene expression in ischemic heart disease gene therapy.

    Science.gov (United States)

    Kim, Hyun Ah; Rhim, Taiyoun; Lee, Minhyung

    2011-07-18

    Ischemic heart diseases are caused by narrowed coronary arteries that decrease the blood supply to the myocardium. In the ischemic myocardium, hypoxia-responsive genes are up-regulated by hypoxia-inducible factor-1 (HIF-1). Gene therapy for ischemic heart diseases uses genes encoding angiogenic growth factors and anti-apoptotic proteins as therapeutic genes. These genes increase blood supply into the myocardium by angiogenesis and protect cardiomyocytes from cell death. However, non-specific expression of these genes in normal tissues may be harmful, since growth factors and anti-apoptotic proteins may induce tumor growth. Therefore, tight gene regulation is required to limit gene expression to ischemic tissues, to avoid unwanted side effects. For this purpose, various gene expression strategies have been developed for ischemic-specific gene expression. Transcriptional, post-transcriptional, and post-translational regulatory strategies have been developed and evaluated in ischemic heart disease animal models. The regulatory systems can limit therapeutic gene expression to ischemic tissues and increase the efficiency of gene therapy. In this review, recent progresses in ischemic-specific gene expression systems are presented, and their applications to ischemic heart diseases are discussed.

  2. Vascular endothelial growth factor (VEGF) regulation by hypoxia inducible factor-1 alpha (HIF1A) starts and peaks during endometrial breakdown, not repair, in a mouse menstrual-like model.

    Science.gov (United States)

    Chen, Xihua; Liu, Jianbing; He, Bin; Li, Yunfeng; Liu, Shuyan; Wu, Bin; Wang, Shufang; Zhang, Shucheng; Xu, Xiangbo; Wang, Jiedong

    2015-09-01

    How is vascular endothelial growth factor (VEGF) expression regulated by hypoxia inducible factor 1 alpha (HIF1A) during menstruation? After progesterone (P4) withdrawal, HIF1A was activated and it directly up-regulated VEGF mRNA expression and this regulation was the highest during endometrium breakdown in the mouse menstrual-like model. VEGF, an important angiogenic factor, is known to be essential for endometrial repair, particularly in angiogenesis and re-epithelialization. However, its upstream regulation has not been fully clarified. HIF1 is the first transcription factor response to hypoxia and is closely associated with angiogenesis; it is also an upstream regulator of VEGF mRNA. We investigated the changes in the expression of HIF1A and VEGF after P4 withdrawal and after HIF1A inhibition. The total number of mice used was 62. The treatment duration in the mouse menstrual-like model was 8 days. The mouse menstrual-like model and mouse and human decidual endometrial stromal cells were established to mimic menstruation. Protein and mRNA expressions of HIF1A and VEGF were investigated by immunohistochemistry, Western blot and quantitative PCR. The direct interaction between HIF1A and the Vegf promoter was also investigated by chromatin immunoprecipitation. HIF1A inhibition in vivo and in vitro was achieved by administration of an HIF1A inhibitor and by siRNA knockdown, respectively. HIF1A was translocated to the nucleus from 8 to 16 h after P4 withdrawal, while VEGF mRNA expression was the highest at 12 h. HIF1A directly bound to Vegf promoter during endometrial breakdown, which peaked at 12 h. HIF1A inhibition suppressed VEGF mRNA and protein expression in the mouse menstrual-like model and decidualized stromal cells. Inhibition of HIF1A also suppressed endometrial breakdown. Although HIF1A regulation of VEGF mRNA was confirmed in the mouse menstrual-like model and decidual endometrium stromal cells, the functional regulation of VEGF protein was not further

  3. Hypoxia-Induced Collagen Synthesis of Human Lung Fibroblasts by Activating the Angiotensin System

    OpenAIRE

    Shan-Shan Liu; Hao-Yan Wang; Jun-Ming Tang; Xiu-Mei Zhou

    2013-01-01

    The exact molecular mechanism that mediates hypoxia-induced pulmonary fibrosis needs to be further clarified. The aim of this study was to explore the effect and underlying mechanism of angiotensin II (Ang II) on collagen synthesis in hypoxic human lung fibroblast (HLF) cells. The HLF-1 cell line was used for in vitro studies. Angiotensinogen (AGT), angiotensin converting enzyme (ACE), angiotensin II type 1 receptor (AT1R) and angiotensin II type 2 receptor (AT2R) expression levels in human ...

  4. Radix Scrophulariae extracts (harpagoside) suppresses hypoxia-induced microglial activation and neurotoxicity

    OpenAIRE

    Sheu, Shiow-Yunn; Hong, Yi-Wen; Sun, Jui-Sheng; Liu, Man-Hai; Chen, Ching-Yun; Ke, Cherng-Jyh

    2015-01-01

    Background Hypoxia could lead to microglia activation and inflammatory mediators’ overproduction. These inflammatory molecules could amplify the neuroinflammatory process and exacerbate neuronal injury. The aim of this study is to find out whether harpagoside could reduce hypoxia-induced microglia activation. Methods In this study, primary microglia cells harvested from neonatal ICR mice were activated by exposure to hypoxia (1 % O2 for 3 h). Harpagoside had been shown to be no cytotoxicity o...

  5. Sildenafil and an early stage of chronic hypoxia-induced pulmonary hypertension in newborn piglets.

    Science.gov (United States)

    Binns-Loveman, Karen M; Kaplowitz, Mark R; Fike, Candice D

    2005-07-01

    Devising therapies that might prevent the onset or progression of pulmonary hypertension in newborns has received little attention. Our major objective was to determine whether sildenafil, a selective phosphodiesterase inhibitor, prevents the development of an early stage of chronic hypoxia-induced pulmonary hypertension in newborn pigs. Another objective was to determine whether sildenafil causes pulmonary vasodilation without systemic vasodilation in piglets with chronic pulmonary hypertension. Piglets were raised in room air (control, n = 5) or 10-11% O(2) (hypoxic, n = 17) for 3 days. Some piglets (n = 4) received oral sildenafil, 12 mg/kg/day, throughout exposure to hypoxia. All piglets were anesthetized and catheterized, and pulmonary arterial pressure (Ppa), pulmonary wedge pressure (Pw), aortic pressure (Ao), and cardiac output (CO) were measured. Then for some piglets raised in hypoxia for 3 days, a single oral sildenafil dose (3 mg/kg, n = 6) or placebo (n = 5) was given, and hemodynamic measurements were repeated. For piglets raised in hypoxia for 3 days, mean Ppa and calculated PVR were elevated above respective values in control piglets. Mean Ppa and PVR did not differ between piglets that received sildenafil throughout exposure to hypoxia and those that did not. For piglets with chronic hypoxia-induced pulmonary hypertension that received a single oral dose of sildenafil, mean Ppa and PVR decreased, while mean Pw, CO, mean Ao, and systemic vascular resistance remained the same. All hemodynamic measurements were unchanged after placebo. Oral sildenafil did not influence the early stage of chronic hypoxia-induced pulmonary hypertension in newborn piglets. However, a single oral dose of sildenafil caused pulmonary vasodilation, without systemic vasodilation, in piglets with chronic hypoxia-induced pulmonary hypertension, which may have therapeutic implications.

  6. Strong iron demand during hypoxia-induced erythropoiesis is associated with down-regulation of iron-related proteins and myoglobin in human skeletal muscle

    DEFF Research Database (Denmark)

    Robach, Paul; Cairo, Gaetano; Gelfi, Cecilia

    2007-01-01

    by decreases in L-ferritin (43%), transferrin receptor (TfR; 50%), and total iron content (37%). This parallel decrease in L-ferritin and TfR in HA occurs independently of increased hypoxia-inducible factor 1 (HIF-1) mRNA levels and unchanged binding activity of iron regulatory proteins, but concurrently...

  7. HIF-1α、VEGF在视网膜母细胞瘤中的表达及意义%Expression and clinical implication of hypoxia-inducible factor-1α and vascular endothelial growth factor in retinoblastoma

    Institute of Scientific and Technical Information of China (English)

    游志鹏; 宋华; 赵菊莲

    2009-01-01

    目的 探讨缺氧诱导因子-1α(HIF-1α)、血管内皮生长因子(VEGF)在视网膜母细胞瘤(RB)组织中表达情况及其在肿瘤血管形成、浸润及转移等生物学行为中作用.方法 应用免疫组织化学方法检测RB组织中HIF-1α蛋白、VEGF蛋白的表达情况,并探讨其表达与肿瘤的分级的相关性及HIF-1α和VEGF两者的相关性.结果 HIF-1α、VEGF蛋白在RB中呈高表达,HIF-1α阳性细胞为肿瘤细胞核染色、部分胞浆染色,VEGF阳性细胞为肿瘤细胞胞浆染色,HIF-1α、VEGF表达在不同临床分期间差异有统计学意义(P<0.05),且其表达和临床分期密切相关(P<0.05);HIF-1α、VEGF二者表达存在正相关(r_s=0.946,P<0.01).结论 HIF-1α及VEGF的高表达与RB的临床分期呈正相关,在RB新生血管形成、肿瘤的浸润、转移中可能发挥重要作用.%Objective The invasion and metastasis of tumor cells depend on the growth of new blood vessels, and tumor neovascularization was regulated by a lots of factors. This study aimed to investigate the expression of hypoxia-inducible factor-1α (HIF -1α) and vascular endothelial growth factor (VECF) in retinoblastoma and explore the correlation of HIF-1α and VEGF with tumor invasion and metastasis and analyze their relationship with clinicopathology characters and determine their effect on angiogenesis. Methods Forty-six retinoblastoma specimens with different clinical stages were collected in Affiliated Second Hospital of Nanchang University. The specimens received neither radiotherapy nor chemotherapy. The retinal tissue near the tumor was as control. Immunohistochemistry was used to detect the expression of HIF-1α protein and VEGF protein in retinoblastoma. The relationship between expression of HIF-1α and VEGF and stage of tumor was analyzed. Results The HIF-1α and VEGF were highly expressed in the ischemia or necrosis area of retinoblastoma. Expression of HIF-1α was mainly in cell nuclear and partly in

  8. Hypobaric-hypoxia-induced pulmonary damage in rats ameliorated by antioxidant erdosteine.

    Science.gov (United States)

    Uzun, Ozge; Balbay, Oner; Comunoğlu, Nil Ustündağ; Yavuz, Ozlem; Nihat Annakkaya, Ali; Güler, Selver; Silan, Coşkun; Erbaş, Mete; Arbak, Peri

    2006-01-01

    Free radical-mediated injury to lung and pulmonary vasculature is an important mechanism in hypoxia-induced lung damage. In this study, we aimed to investigate the potential protective effects of erdosteine as an antioxidant agent on hypobaric hypoxia-induced pulmonary hypertension. Adult male rats were assigned randomly to three groups. The first group of rats was exposed to hypobaric-hypoxia and the second group was treated with erdosteine (20mg/kg, daily) for 2 weeks, during which time they were in a hypoxic chamber. These groups were compared with normoxic controls. All rats were sacrificed after 2 weeks. The hypoxia-induced increase in right ventricle to left ventricle plus septum weight ratio (from 0.20+/-0.01 to 0.26+/-0.01) was reduced significantly in the erdosteine-treated group (0.23+/-0.01). Malondialdehyde levels were elevated (from 0.33+/-0.11 to 0.59+/-0.02) and total antioxidant status was not changed significantly (from 1.77+/-0.42 to 2.61+/-0.23) by hypoxia. In contrast to the hypoxia-exposed group, malondialdehyde levels were significantly decreased in the erdosteine-treated group (0.37+/-0.02). Total antioxidant status (4.03+/-0.22) was significantly higher in erdosteine-treated rats when compared to non-treated rats. Histopathological examination demonstrated that erdosteine prevented inflammation and protected lung parenchyma and pulmonary endothelium of hypoxia-exposed rats.

  9. Identification of crucial microRNAs and genes in hypoxia-induced human lung adenocarcinoma cells

    Directory of Open Access Journals (Sweden)

    Geng Y

    2016-07-01

    Full Text Available Ying Geng,1,* Lili Deng,2,* Dongju Su,1 Jinling Xiao,1 Dongjie Ge,3 Yongxia Bao,1 Hui Jing4 1Department of Respiratory, 2Department of Oncology, The Second Affiliated Hospital of Harbin Medical University, 3Department of Respiratory, The First Hospital of Harbin, 4Department of Emergency, The Second Affiliated Hospital of Harbin Medical University Harbin, Heilongjiang, People’s Republic of China *These authors contributed equally to this work Background: Variations of microRNA (miRNA expression profile in hypoxic lung cancer cells have not been studied so far. Therefore, using miRNA microarray technology, this study aimed to study the miRNA expression profile and investigate the potential crucial miRNAs and their target genes in hypoxia-induced human lung adenocarcinoma cells.Materials and methods: Based on miRNA microarray, miRNA expression profiling of hypoxia-induced lung adenocarcinoma A549 cells was obtained. After identification of differentially expressed miRNAs (DE-miRNAs in hypoxic cells, target genes of DE-miRNAs were predicted, and functional enrichment analysis of targets was conducted. Furthermore, the expression levels of DE-miRNAs and their target genes were validated by real-time quantitative polymerase chain reaction. In addition, using miRNA mimics, the effect of overexpressed DE-miRNAs on A549 cell behaviors (cell proliferation, cell cycle, and apoptosis was evaluated.Results: In total, 14 DE-miRNAs (nine upregulated miRNAs and five downregulated miRNAs were identified in hypoxic cells, compared with normoxic cells. Target genes of both upregulated and downregulated miRNAs were enriched in the functions such as chromatin modification, and pathways such as Wnt signaling pathway and transforming growth factor (TGF-β signaling pathway. The expression levels of several miRNAs and their target genes were confirmed, including hsa-miR-301b/FOXF2, hsa-miR-148b-3p/WNT10B, hsa-miR-769-5p/(SMAD2, ARID1A, and hsa-miR-622. Among them

  10. Endothelin-1 mediates intermittent hypoxia-induced inflammatory vascular remodeling through HIF-1 activation.

    Science.gov (United States)

    Gras, Emmanuelle; Belaidi, Elise; Briançon-Marjollet, Anne; Pépin, Jean-Louis; Arnaud, Claire; Godin-Ribuot, Diane

    2016-02-15

    Obstructive sleep apnea (OSA) is a major risk factor for cardiovascular mortality, and apnea-induced intermittent hypoxia (IH) is known to promote various cardiovascular alterations such as vascular remodeling. However, the mechanisms that underlie IH remain incompletely investigated. We previously demonstrated that the hypoxia-inducible factor-1 (HIF-1) and endothelin-1 (ET-1) are involved in arterial hypertension and myocardial susceptibility to infarction induced by IH. Thus the objective of the present study was to investigate whether both ET-1 and HIF-1 were also involved in the vascular inflammatory remodeling induced by IH. Mice partially deficient for the Hif1α gene (HIF-1α(+/-)) and their wild-type equivalents, as well as C57BL/6J mice, treated or not with bosentan, a dual endothelin receptor antagonist, were exposed to IH or normoxia for 2 wk, 8 h/day. Splenocyte proliferative and secretory capacities, aortic nuclear factor-κB (NF-κB) and HIF-1 activities, and expression of cytokines and intima-media thickness (IMT) were measured. IH induced a systemic and aortic inflammation characterized by an increase in splenocyte proliferative and secretory capacities, aortic NF-κB activity, and cytokine expression in the aortic wall. This was accompanied by an increase in IMT. These modifications were prevented in HIF-1α(+/-) and bosentan-treated mice. The results of this study suggest that ET-1 is a major contributor to the vascular inflammatory remodeling induced by OSA-related IH, probably through HIF-1-dependent activation of NF-κB.

  11. Chronic intermittent hypoxia induces cardiac inflammation and dysfunction in a rat obstructive sleep apnea model.

    Science.gov (United States)

    Wei, Qin; Bian, Yeping; Yu, Fuchao; Zhang, Qiang; Zhang, Guanghao; Li, Yang; Song, Songsong; Ren, Xiaomei; Tong, Jiayi

    2016-11-01

    Chronic intermittent hypoxia is considered to play an important role in cardiovascular pathogenesis during the development of obstructive sleep apnea (OSA). We used a well-described OSA rat model induced with simultaneous intermittent hypoxia. Male Sprague Dawley rats were individually placed into plexiglass chambers with air pressure and components were electronically controlled. The rats were exposed to intermittent hypoxia 8 hours daily for 5 weeks. The changes of cardiac structure and function were examined by ultrasound. The cardiac pathology, apoptosis, and fibrosis were analyzed by H&E staining, TUNNEL assay, and picosirius staining, respectively. The expression of inflammation and fibrosis marker genes was analyzed by quantitative real-time PCR and Western blot. Chronic intermittent hypoxia/low pressure resulted in significant increase of left ventricular internal diameters (LVIDs), end-systolic volume (ESV), end-diastolic volume (EDV), and blood lactate level and marked reduction in ejection fraction and fractional shortening. Chronic intermittent hypoxia increased TUNNEL-positive myocytes, disrupted normal arrangement of cardiac fibers, and increased Sirius stained collagen fibers. The expression levels of hypoxia induced factor (HIF)-1α, NF-kB, IL-6, and matrix metallopeptidase 2 (MMP-2) were significantly increased in the heart of rats exposed to chronic intermittent hypoxia. In conclusion, the left ventricular function was adversely affected by chronic intermittent hypoxia, which is associated with increased expression of HIF-1α and NF-kB signaling molecules and development of cardiac inflammation, apoptosis and fibrosis.

  12. 低氧诱导因子-1α与口腔扁平苔藓%Hypoxia-inducible factor-1α and oral lichen planus

    Institute of Scientific and Technical Information of China (English)

    王夏夏; 孙红英

    2015-01-01

    Hypoxia-inducible factor(HIF)-1 is an important transcription factor in cellular adaptation to hypoxic conditions is involved in regulating immune cell differentiation, promoting the adhesion and influence the formation of cell metabolism, inducing new blood vessels, and regulating cell proliferation and apoptosis, among others. In recent years, studies have shown that HIF-1α may play an important role in the pathogenesis of oral lichen planus. This article reviewed the research progress onHIF-1inthe following aspects: the structure, function, and regulation of HIF-1, immune inflammatory response in the expression of HIF-1α, and the role of HIF-1α in the occurrence and development of oral lichen planus.%低氧诱导因子(HIF)-1是机体低氧反应中的重要转录因子,在免疫炎症反应中参与调控免疫细胞分化、促进黏附、影响细胞代谢、诱导新生血管形成、调控细胞增殖与凋亡等。近年研究表明,HIF-1α在口腔扁平苔藓的发生发展过程中可能发挥着重要作用,本文将从HIF-1的结构、功能及调控,免疫炎症反应中HIF-1α的表达, HIF-1α在口腔扁平苔藓发生、发展中的作用等方面作一综述。

  13. TanshinoneIIA and cryptotanshinone protect against hypoxia-induced mitochondrial apoptosis in H9c2 cells.

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    Hyou-Ju Jin

    Full Text Available Mitochondrial apoptosis pathway is an important target of cardioprotective signalling. Tanshinones, a group of major bioactive compounds isolated from Salvia miltiorrhiza, have been reported with actions against inflammation, oxidative stress, and myocardial ischemia reperfusion injury. However, the actions of these compounds on the chronic hypoxia-related mitochondrial apoptosis pathway have not been investigated. In this study, we examined the effects and molecular mechanisms of two major tanshonones, tanshinone IIA (TIIA and cryptotanshinone (CT on hypoxia induced apoptosis in H9c2 cells. Cultured H9c2 cells were treated with TIIA and CT (0.3 and 3 μΜ 2 hr before and during an 8 hr hypoxic period. Chronic hypoxia caused a significant increase in hypoxia inducible factor 1α expression and the cell late apoptosis rate, which was accompanied with an increase in caspase 3 activity, cytochrome c release, mitochondria membrane potential and expression of pro-apoptosis proteins (Bax and Bak. TIIA and CT (0.3 and 3 μΜ, in concentrations without affecting the cell viability, significantly inhibited the late apoptosis and the changes of caspase 3 activity, cytochrome c release, and mitochondria membrane potential induced by chronic hypoxia. These compounds also suppressed the overexpression of Bax and reduced the ratio of Bax/Bcl-2. The results indicate that TIIA and CT protect against chronic hypoxia induced cell apoptosis by regulating the mitochondrial apoptosis signaling pathway, involving inhibitions of mitochondria hyperpolarization, cytochrome c release and caspase 3 activity, and balancing anti- and pro-apoptotic proteins in Bcl-2 family proteins.

  14. Hypoxia-induced nitric oxide production and tumour perfusion is inhibited by pegylated arginine deiminase (ADI-PEG20).

    Science.gov (United States)

    Burrows, Natalie; Cane, Gaelle; Robson, Mathew; Gaude, Edoardo; Howat, William J; Szlosarek, Peter W; Pedley, R Barbara; Frezza, Christian; Ashcroft, Margaret; Maxwell, Patrick H

    2016-03-14

    The hypoxic tumour microenvironment represents an aggressive, therapy-resistant compartment. As arginine is required for specific hypoxia-induced processes, we hypothesised that arginine-deprivation therapy may be useful in targeting hypoxic cancer cells. We explored the effects of the arginine-degrading agent ADI-PEG20 on hypoxia-inducible factor (HIF) activation, the hypoxia-induced nitric oxide (NO) pathway and proliferation using HCT116 and UMUC3 cells and xenografts. The latter lack argininosuccinate synthetase (ASS1) making them auxotrophic for arginine. In HCT116 cells, ADI-PEG20 inhibited hypoxic-activation of HIF-1α and HIF-2α, leading to decreased inducible-nitric oxide synthase (iNOS), NO-production, and VEGF. Interestingly, combining hypoxia and ADI-PEG20 synergistically inhibited ASS1. ADI-PEG20 inhibited mTORC1 and activated the unfolded protein response providing a mechanism for inhibition of HIF and ASS1. ADI-PEG20 inhibited tumour growth, impaired hypoxia-associated NO-production, and decreased vascular perfusion. Expression of HIF-1α/HIF-2α/iNOS and VEGF were reduced, despite an increased hypoxic tumour fraction. Similar effects were observed in UMUC3 xenografts. In summary, ADI-PEG20 inhibits HIF-activated processes in two tumour models with widely different arginine biology. Thus, ADI-PEG20 may be useful in the clinic to target therapy-resistant hypoxic cells in ASS1-proficient tumours and ASS1-deficient tumours.

  15. ACLY and ACC1 Regulate Hypoxia-Induced Apoptosis by Modulating ETV4 via α-ketoglutarate.

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    Melissa M Keenan

    2015-10-01

    Full Text Available In order to propagate a solid tumor, cancer cells must adapt to and survive under various tumor microenvironment (TME stresses, such as hypoxia or lactic acidosis. To systematically identify genes that modulate cancer cell survival under stresses, we performed genome-wide shRNA screens under hypoxia or lactic acidosis. We discovered that genetic depletion of acetyl-CoA carboxylase (ACACA or ACC1 or ATP citrate lyase (ACLY protected cancer cells from hypoxia-induced apoptosis. Additionally, the loss of ACLY or ACC1 reduced levels and activities of the oncogenic transcription factor ETV4. Silencing ETV4 also protected cells from hypoxia-induced apoptosis and led to remarkably similar transcriptional responses as with silenced ACLY or ACC1, including an anti-apoptotic program. Metabolomic analysis found that while α-ketoglutarate levels decrease under hypoxia in control cells, α-ketoglutarate is paradoxically increased under hypoxia when ACC1 or ACLY are depleted. Supplementation with α-ketoglutarate rescued the hypoxia-induced apoptosis and recapitulated the decreased expression and activity of ETV4, likely via an epigenetic mechanism. Therefore, ACC1 and ACLY regulate the levels of ETV4 under hypoxia via increased α-ketoglutarate. These results reveal that the ACC1/ACLY-α-ketoglutarate-ETV4 axis is a novel means by which metabolic states regulate transcriptional output for life vs. death decisions under hypoxia. Since many lipogenic inhibitors are under investigation as cancer therapeutics, our findings suggest that the use of these inhibitors will need to be carefully considered with respect to oncogenic drivers, tumor hypoxia, progression and dormancy. More broadly, our screen provides a framework for studying additional tumor cell stress-adaption mechanisms in the future.

  16. Fucoidan Suppresses Hypoxia-Induced Lymphangiogenesis and Lymphatic Metastasis in Mouse Hepatocarcinoma.

    Science.gov (United States)

    Teng, Hongming; Yang, Yazong; Wei, Hengyun; Liu, Zundong; Liu, Zhichao; Ma, Yanhong; Gao, Zixiang; Hou, Lin; Zou, Xiangyang

    2015-06-03

    Metastasis, the greatest clinical challenge associated with cancer, is closely connected to multiple biological processes, including invasion and adhesion. The hypoxic environment in tumors is an important factor that causes tumor metastasis by activating HIF-1α. Fucoidan, extracted from brown algae, is a sulfated polysaccharide and, as a novel marine biological material, has been used to treat various disorders in China, Korea, Japan and other countries. In the present study, we demonstrated that fucoidan derived from Undaria pinnatifida sporophylls significantly inhibits the hypoxia-induced expression, nuclear translocation and activity of HIF-1α, the synthesis and secretion of VEGF-C and HGF, cell invasion and lymphatic metastasis in a mouse hepatocarcinoma Hca-F cell line. Fucoidan also suppressed lymphangiogenesis in vitro and in vivo. In addition, accompanied by a reduction in the HIF-1α nuclear translocation and activity, fucoidan significantly reduced the levels of p-PI3K, p-Akt, p-mTOR, p-ERK, NF-κB, MMP-2 and MMP-9, but increased TIMP-1 levels. These results indicate strongly that the anti-metastasis and anti-lymphangiogenesis activities of fucoidan are mediated by suppressing HIF-1α/VEGF-C, which attenuates the PI3K/Akt/mTOR signaling pathways.

  17. Fucoidan Suppresses Hypoxia-Induced Lymphangiogenesis and Lymphatic Metastasis in Mouse Hepatocarcinoma

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    Hongming Teng

    2015-06-01

    Full Text Available Metastasis, the greatest clinical challenge associated with cancer, is closely connected to multiple biological processes, including invasion and adhesion. The hypoxic environment in tumors is an important factor that causes tumor metastasis by activating HIF-1α. Fucoidan, extracted from brown algae, is a sulfated polysaccharide and, as a novel marine biological material, has been used to treat various disorders in China, Korea, Japan and other countries. In the present study, we demonstrated that fucoidan derived from Undaria pinnatifida sporophylls significantly inhibits the hypoxia-induced expression, nuclear translocation and activity of HIF-1α, the synthesis and secretion of VEGF-C and HGF, cell invasion and lymphatic metastasis in a mouse hepatocarcinoma Hca-F cell line. Fucoidan also suppressed lymphangiogenesis in vitro and in vivo. In addition, accompanied by a reduction in the HIF-1α nuclear translocation and activity, fucoidan significantly reduced the levels of p-PI3K, p-Akt, p-mTOR, p-ERK, NF-κB, MMP-2 and MMP-9, but increased TIMP-1 levels. These results indicate strongly that the anti-metastasis and anti-lymphangiogenesis activities of fucoidan are mediated by suppressing HIF-1α/VEGF-C, which attenuates the PI3K/Akt/mTOR signaling pathways.

  18. Melatonin Suppresses Hypoxia-Induced Migration of HUVECs via Inhibition of ERK/Rac1 Activation

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    Ling Yang

    2014-08-01

    Full Text Available Melatonin, a naturally-occurring hormone, possesses antioxidant properties and ameliorates vascular endothelial dysfunction. In this study, we evaluate the impact of melatonin on the migratory capability of human umbilical vein endothelial cells (HUVECs to hypoxia and further investigate whether ERK/Rac1 signaling is involved in this process. Here, we found that melatonin inhibited hypoxia-stimulated hypoxia-inducible factor-1α (HIF-1α expression and cell migration in a dose-dependent manner. Mechanistically, melatonin inhibited Rac1 activation and suppressed the co-localized Rac1 and F-actin on the membrane of HUVECs under hypoxic condition. In addition, the blockade of Rac1 activation with ectopic expression of an inactive mutant form of Rac1-T17N suppressed HIF-1α expression and cell migration in response to hypoxia, as well, but constitutive activation of Rac1 mutant Rac1-V12 restored HIF-1α expression, preventing the inhibition of melatonin on cell migration. Furthermore, the anti-Rac1 effect of melatonin in HUVECs appeared to be associated with its inhibition of ERK phosphorylation, but not that of the PI3k/Akt signaling pathway. Taken together, our work indicates that melatonin exerts an anti-migratory effect on hypoxic HUVECs by blocking ERK/Rac1 activation and subsequent HIF-1α upregulation.

  19. Association of Hypoxia-Inducible Factor-2 Alpha Gene Polymorphisms with the Risk of Hepatitis B Virus-Related Liver Disease in Guangxi Chinese: A Case-Control Study.

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    Liling Huang

    Full Text Available Hypoxia-inducible factor-2 alpha (HIF-2a plays a major role in the progression of disease, although the role of HIF-2α gene polymorphisms in hepatitis B virus (HBV-related diseases remains elusive. The aim of this study is to determine whether HIF-2a rs13419896 and rs6715787 single-nucleotide polymorphisms (SNPs are associated with susceptibility to chronic hepatitis B (CHB, liver cirrhosis (LC, or hepatocellular carcinoma (HCC.A case-control study of 107 patients with CHB, 83 patients with LC, 234 patients with HCC, and 224 healthy control subjects was carried out, and the HIF-2a rs13419896 and rs6715787 SNPs were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP.No significant differences were observed in the genotype or allele frequency of two HIF-2a SNPs between the cases and controls (all p>0.05. However, in subgroup analysis by gender, the HIF-2a rs13419896 GA and AA genotypes were significantly associated with a risk of CHB (odds ratio [OR] = 3.565, 95% confidence interval [CI] = 1.123-11.314, p = 0.031 and OR = 12.506, 95% CI = 1.329-117.716, p = 0.027 in females, and the A allele of rs13419896 was associated with a risk of CHB (OR = 2.624, 95% CI = 1.244-5.537, p = 0.011 and LC (OR = 2.351, 95% CI = 1.002-5.518, p = 0.050 in females. The rs6715787 CG genotype polymorphism may contribute to a reduced risk of LC in the Guangxi Zhuang Chinese population (OR = 0.152, 95% CI = 0.028-0.807, p = 0.027, as determined via subgroup analysis by ethnicity. Moreover, binary logistic regression analyses that were adjusted by drinking status indicated that the AA genotype of rs13419896 may contribute to an increased risk of LC in the non-alcohol-drinking population (OR = 3.124, 95% CI = 1.091-8.947, p = 0.034. In haplotype analysis, GG haplotype was significantly associated with a reduced risk of LC (OR = 0.601, 95% CI = 0.419-0.862, p = 0.005.The HIF-2a rs13419896 polymorphism is associated with an increased

  20. Prolyl hydroxylase 2 dependent and Von-Hippel-Lindau independent degradation of Hypoxia-inducible factor 1 and 2 alpha by selenium in clear cell renal cell carcinoma leads to tumor growth inhibition

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    Chintala Sreenivasulu

    2012-07-01

    Full Text Available Abstract Background Clear cell renal cell carcinoma (ccRCC accounts for more than 80% of the cases of renal cell carcinoma. In ccRCC deactivation of Von-Hippel-Lindau (VHL gene contributes to the constitutive expression of hypoxia inducible factors 1 and 2 alpha (HIF-α, transcriptional regulators of several genes involved in tumor angiogenesis, glycolysis and drug resistance. We have demonstrated inhibition of HIF-1α by Se-Methylselenocysteine (MSC via stabilization of prolyl hydroxylases 2 and 3 (PHDs and a significant therapeutic synergy when combined with chemotherapy. This study was initiated to investigate the expression of PHDs, HIF-α, and VEGF-A in selected solid cancers, the mechanism of HIF-α inhibition by MSC, and to document antitumor activity of MSC against human ccRCC xenografts. Methods Tissue microarrays of primary human cancer specimens (ccRCC, head & neck and colon were utilized to determine the incidence of PHD2/3, HIF-α, and VEGF-A by immunohistochemical methods. To investigate the mechanism(s of HIF-α inhibition by MSC, VHL mutated ccRCC cells RC2 (HIF-1α positive, 786–0 (HIF-2α positive and VHL wild type head & neck cancer cells FaDu (HIF-1α were utilized. PHD2 and VHL gene specific siRNA knockdown and inhibitors of PHD2 and proteasome were used to determine their role in the degradation of HIF-1α by MSC. Results We have demonstrated that ccRCC cells express low incidence of PHD2 (32%, undetectable PHD3, high incidence of HIF-α (92%, and low incidence of VEGF-A compared to head & neck and colon cancers. This laboratory was the first to identify MSC as a highly effective inhibitor of constitutively expressed HIF-α in ccRCC tumors. MSC did not inhibit HIF-1α protein synthesis, but facilitated its degradation. The use of gene knockdown and specific inhibitors confirmed that the inhibition of HIF-1α was PHD2 and proteasome dependent and VHL independent. The effects of MSC treatment on HIF-α were associated with

  1. 冻干重组人三突变型低氧诱导因子-1α腺病毒的制备%Preparation of freeze-dried recombinant adenovirus expressing hypoxia inducible factor-1 alpha of triple mutant

    Institute of Scientific and Technical Information of China (English)

    陶宇; 杨丽; 魏旋; 李明琰; 陈建威; 吴平生

    2011-01-01

    目的:研制冻干重组人三突变型低氧诱导因子-1α(HIF-1α)腺病毒.方法:将重组人三突变型HIF-1α腺病毒与不同配比的保护剂按适当比例混合,进行冻干,根据冻干后外观、病毒滴度测定、热稳定性试验、PCR、基因测序等结果,筛选冻干保护剂并评价冻干品质量.结果:冻干腺病毒所携带的目的基因信息无丢失或变异;以10%海藻糖、0.5%明胶、3%山梨醇等成分配制的保护剂作用较好,冻干后腺病毒感染性滴度下降0.33 LgPFU/mL;37℃放置3周,滴度下降0.8 LgPFU/mL.结论:以合适的保护剂制备冻干重组人三突变型HIF-1α腺病毒能达到较满意的效果.%Objective To prepare freeze-dried recomhinant adenovirus expressing hypoxia inducible factor-1 alpha (HIF-lα) of triple mutant (Ad-HIF-lα-564/402/803). Methods Ad-HIF-Iα-564/402/803 were mixed with different stabilizers in an appropriate proportion and then lyophilized. The optimum stabilizer was selected and the product quality was evaluated according to appearance, virus titer, thermostahility, PCR and DNA sequence analvsis. Results PCR and gene sequence suggested the correct construction of freeze-dried recombinant adenovirus. The protective agent containing 10% trehalose , 0.5% gelatin, 3% sorbitol had bett