HIF-1alpha Protein Expression Research Articles

Endogenous reactive oxygen species and nitric oxide have opposite roles in regulating HIF-1alpha expression in hypoxic astrocytes.

Ischemic stroke results in cerebral tissue hypoxia and increased expression of hypoxia-inducible factor (HIF), which is critically implicated in ischemic brain injury. Understanding the mechanisms of HIF-1alpha regulation in the ischemic brain has been an important research focus. The generation of both nitric oxide (NO) and reactive oxygen species (ROS) is increased under hypoxic/ischemic conditions and each of them has been independently shown to regulate HIF-1alpha expression. In this study, we investigated the cross-effects of NO and ROS on the expression of HIF-1alpha in hypoxic astrocytes. Exposure of astrocytes to 2 h-hypoxia remarkably increased HIF-1alpha protein levels, which was accompanied by increased NO and ROS production. Decreasing ROS with NAC, NADPH oxidase inhibitor DPI, or SOD mimetic MnTMPyP decreased hypoxia-induced HIF-1alpha protein accumulation and increased NO level in hypoxic astrocytes. The NO synthase (NOS) inhibitor L-NAME inhibited ROS generation, which led to a reduction in hypoxia-induced HIF-1alpha protein expression. Although NOS inhibitor or ROS scavengers alone reduced HIF-1alpha protein levels, the reduction was reversed when NOS inhibitor and ROS scavenger present together. The NO scavenger PTIO increased hypoxia-induced HIF-1alpha protein expression and ROS production, while HIF-1alpha protein level was decreased in the presence of NO scavenger and ROS scavenger together. These results suggest that ROS, NO, and their interaction critically contribute to the regulation of hypoxia-induced HIF-1alpha protein accumulation under hypoxic condition. Furthermore, our results indicate that hypoxia-induced NO generation may represent an endogenous mechanism for balancing ROS-mediated hypoxic stress, as reflected by inhibiting hypoxia-induced HIF-1alpha protein accumulation.

DIPG-67. HYPOXIA-INDUCIBLE FACTORS REGULATE DIFFUSE INTRINSIC PONTINE GLIOMA GROWTH IN NORMOXIC CULTURE

Diffuse intrinsic pontine glioma (DIPG) are incurable tumors and the leading cause of pediatric brain tumor deaths. They exhibit low blood perfusion and regions of necrosis, indicative of a low-oxygen environment that supports activation of hypoxia-inducible factors (HIF) that are associated with increased proliferation, invasion, and therapy resistance. However, previous reports suggest that HIF2-alpha slows growth in some glioma models. We therefore sought to test the hypothesis that HIFs regulate DIPG growth. We cultured the human DIPG tumors SU-DIPG-IV, VUMC-DIPG-X, and SU-DIPG-XIII at ambient oxygen tension and 5% carbon dioxide. We measured protein expression by Western blot and growth by trypan blue exclusion or tetrazolium reduction following exposure to the hypoxia-mimetic (HM) compounds, cobalt (II) chloride or deferoxamine, or selective HIF inhibitors. All three DIPG cultures retained stable expression of HIF1-alpha and HIF2-alpha protein at ambient oxygen tension, unchanged by HM treatment. Selective inhibition of HIF2-alpha by TC-S 7009 increased apparent growth, whereas selective inhibition of HIF1-alpha by CAY10585 did not. We conclude that hypoxia-independent HIF expression unchanged by either HM treatment or HIF inhibition suggests impaired HIF degradation, in which hypoxia-induced activation of HIF target genes more likely depends on transcriptional co-activators rather than blocked proteasomal degradation. In both ambient and hypoxic conditions, HIF2-alpha activity may oppose DIPG growth. Future experiments will investigate whether the effects of HIF2-alpha inhibition on tumor growth can be explained by enhanced HIF1-alpha activity through desequestration of common binding partners, or through direct action of HIF2-alpha on previously reported apoptotic pathways.

Characterizing The Effects of Ascorbic Acid and Hyperbaric Oxygen on Glioblastoma Cells

There is emerging evidence supporting the use of intravenous ascorbic acid (AA) as a pro‐oxidative, non‐toxic adjuvant therapy. Before AA is implicated in the clinic, however, more research needs to be conducted to better understand AA's mechanisms of action, and to determine what cancers would be most amenable to this adjunctive therapy. When administered intravenously, AA can achieve pharmacological, millimolar concentrations (~0.3–20 mM) and act as a pro‐oxidant in tumorous tissue, contrary to its antioxidant effects observed with oral administration, which produces micromolar, physiological concentrations (≤0.1 mM). Our study aims to evaluate the effects of pharmacological AA on glioblastoma cells (VM‐M3 and U87), and to see if another pro‐oxidative therapy, hyperbaric oxygen (HBOT), can sensitize cells to treatment. We hypothesize that 1‐hour treatment with AA will decrease VM‐M3 and U87 cell viability, and that co‐treatment with antioxidant N‐Acetylcysteine (NAC) will attenuate cell death. We also hypothesize that hydrogen peroxide mediates AA‐induced VM‐M3 and U87 cell death, and thus that exogenous catalase treatment will attenuate this effect. It was found that 1‐hour treatment with pharmacological AA decreased viability in both VM‐M3 and U87 cells, with VM‐M3 cells exhibiting greater sensitivity to treatment (assessed with crystal violet staining). HBOT did not enhance AA‐induced cytotoxicity in U87 cells; however, HBOT did sensitize VM‐M3 cells to AA treatment. Additionally, 1‐hour co‐treatment with AA and NAC, as well as AA and catalase, rescued cell death in U87 and VM‐M3 cells, suggesting that AA‐induced oxidative stress is mediated by hydrogen peroxide. This study also investigates the effects of AA and HBOT on HIF‐1 alpha, catalase, and transferrin receptor protein expression, yielding further insight into the pro‐oxidative role of AA in cancer.Support or Funding InformationWork supported by: American Physiological Society Undergraduate Research Excellence Fellowship (APS UGREF); Foundation (501c3); Metabolic Therapy and Cancer Research Account (#250244); Scivation: Florida High Tech Corridor Funding (#MED052‐0061361).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Abstract B25: Meformin and LY294002 treatment regulate angiogenesis process through PI3K-MAPK/AKT/mTOR signaling pathways in mammary tumors

Abstract Introduction: The angiogenesis process is regulated by numerous factors, especially the hypoxia-inducible factor 1alpha (HIF-1 alpha) and vascular endothelial growth factor (VEGF). The HIF-1 is a central regulator of pathophysiologic response of cells to hypoxia conditions, able to activate transcription of the gene that promotes the induction of VEGF, which in turn promotes angiogenesis through its ability to stimulate growth, migration, and invasion of endothelial cells, leading to the formation of new blood vessels and subsequent tumor growth. Metformin has demonstrated its ability to reduce the incidence of cancer in diabetic patients with positive results, especially in breast cancer, inhibiting cell growth by AMPK/Akt/mTOR signaling pathway. Likewise, LY294002, a PI3K signaling pathway inhibitor, has antiangiogenic features. In this context, the aim of this study was to evaluate the effectiveness of metformin and LY294002 inhibitor treatment in angiogenesis as a therapeutic strategy in mammary tumors in an in vitro and in vivo study. Materials and Methods: In the in vitro study, canine mammary tumor cell line (CF41) was cultured in DMEM high-glucose culture medium, at 37°C in 5% CO2. Cell viability was measured by MTT assay after treatment with different concentrations of metformin and LY294002 inhibitor. Once established the concentration of 5 mM for metformin and 5 µM of LY294002, the protein and gene expression of HIF-1alpha and VEGF were detected by immunocytochemistry and real-time PCR, respectively. For an in vivo study, CF41 were injected in nude athymic female mice and treated with metformin (200 mg/kg i.p.) for 4 weeks and LY294002 (7.5 mg/kg intratumorally) every 3 days for three times. At the end, mice were euthanized and the tumors were collected to determine the protein and gene expression of HIF-1alpha and VEGF and microvessel density by immunohistochemistry for CD31. The immunostaining was quantified by optical densitometry technique, slides were analyzed and photographed in Nikon Eclipse E200 microscope at 40X objective, and proteins were quantified by the ImageJ software analysis. For real-time PCR, the relative expression of the genes of interest was determined by DataAssist v3.0 software, using Ct method. Results: There was a significant decrease of cell viability after treatment with different concentrations of metformin and LY294002 in 24 hours. Both HIF-1alpha and VEGFA protein and gene expression significantly decreased after treatment with metformin and LY294002 or in combination. Furthermore, in animals, there was a decrease in tumor size, protein and gene expression of HIF-1alpha and VEGFA, in addition to a decrease of CD31 expression after all treatments. Conclusion: Our results suggest the potential effectiveness of metformin and LY294002 acting in angiogenesis process of mammary tumors. Financial support: FAPESP. Citation Format: Marina Gobbe Moschetta, Camila Leonel, Larissa Bazela Maschio-Signorini, Thaiz Ferraz Borin, Gabriela Bottaro Gelaleti, Lívia Carvalho Ferreira, Bruna Victorasso Jardim-Perassi, Nathália Martins Sonehara, Debora Aparecida Pires de Campos Zuccari. Meformin and LY294002 treatment regulate angiogenesis process through PI3K-MAPK/AKT/mTOR signaling pathways in mammary tumors [abstract]. In: Proceedings of the AACR International Conference held in cooperation with the Latin American Cooperative Oncology Group (LACOG) on Translational Cancer Medicine; May 4-6, 2017; São Paulo, Brazil. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(1_Suppl):Abstract nr B25.

A hypoxia response element in the Vegfa promoter is required for basal Vegfa expression in skin and for optimal granulation tissue formation during wound healing in mice.

Hypoxia in skin wounds is thought to contribute to healing through the induction of hypoxia inducible factor-1 (HIF-1). Although HIF-1 can regulate the expression of vascular endothelial growth factor A (Vegfa), whether hypoxia and HIF-1 are required to induce Vegfa expression in the context of wound healing is unknown. To test this hypothesis, we evaluated Vegfa expression and wound healing in mutant mice that lack a functional HIF-1 binding site in the Vegfa promoter. Full-thickness excisional wounds were made using a biopsy punch, left to heal by second intention, and granulation tissue isolated on a time course during healing. mRNA levels of Vegfa and its target genes platelet-derived growth factors B (Pdgfb) and stromal cell-derived factor-1 (Sdf1) were measured by RT-qPCR, and HIF-1alpha and VEGFA protein levels measured by immunoblotting. Lower levels of Vegfa, Pdgf1 and Sdf1 mRNA were found in intact skin of mutant mice relative to wild-type controls (n = 6 mice/genotype), whereas levels in granulation tissue during wound healing were unaltered. VEGFA protein levels were also lower in intact skin of the mutant versus the wild-type mice. Decreased Vegfa mRNA levels in skin of mutant mice could not be attributed to decreased HIF-1alpha protein expression, and were therefore a consequence of the loss of HIF-1 responsiveness of the Vegfa promoter. Comparative histologic analyses of healing wounds in mutant and wild-type mice (n = 8 mice/genotype) revealed significant defects in granulation tissue in the mutant mice, both in terms of quantity and capillary density, although epithelialization and healing rates were unaltered. We conclude that HIF-1 is not a major regulator of Vegfa expression during wound healing; rather, it serves to maintain basal levels of expression of Vegfa and its target genes in intact skin, which are required for optimal granulation tissue formation in response to wounding.

Morphological and immunoistochemical evaluation of cadaveric gingival specimens to estimate the post-mortem Interval

The estimation of the post-mortem interval (PMI) is a critical step in forensic medicine and remains one of the most challenging variables to determine. In general, the numerous methods currently used in estimating post-mortem interval yield to large post-mortem windows, are influenced by several factors and sometime contradict each other. With the aim to obtain a much more accurate determination of the post-mortem interval we combined morphological ultrastructural and immunoistochemical analyses to reach a more detailed knowledge on tissue organization and degradation after death. Samples of gingival tissues obtained from 20 cadavers at different post-mortem intervals were processed for transmission electron microscopy to evaluate ultrastructural modifications in the epithelium and connective tissue. Gingival cells and the extracellular matrix of gingival tissues have been observed by a transmission electron microscopy (TEM) in combination with the evaluation of potential post-mortem biochemical markers, with the final goal to find a tight correlation between the ultrastructural modifications, the biomarker expression and the time of death. All the samples were also immunostained with anti-hypoxia-induced factor 1-α (HIF1-α) antibody, a transcription factor expressed in response to hypoxia, in order to evaluate the expression of HIF1-α, and to establish a correlation between the protein presence and the time of death. Results showed nuclear chromatin changes and cytoplasmic vacuolization in both epithelial and connective tissues and a different pattern of expression of HIF1alpha protein that correlate to the time of death. In conclusion, our preliminary findings suggest that ultrastructural investigations in combination with immunohistochemistry techniques in gingival specimens may represent a new tool to accurately and systematically estimate post-mortem interval.

Implication of VHL, ERK5, and HIF-1alpha in clear cell renal cell carcinoma: Molecular basis

ObjectivesTo determine the expression status of several proteins related to VHL gene function and its relationship with common clinicopathological parameters. Material and methodsObservational, analytical, cross-sectional study with 50 patients diagnosed with clear cell renal cell carcinoma. The study analyzed VHL mutations and hypermethylation as well as protein expression of VHL, CA-IX, HIF-1alpha, VEGF, ERK1/2, and ERK5, relating them to clinical variables.A bivariate and multivariate descriptive logistical regression analysis was performed, using the presence of metastasis at diagnosis as dependent variable. ResultsThe study identified 13 (26%) VHL mutations related to nuclear grade (P = 0.036). VHL hypermethylation was found in 20% of cases. VHL expression was associated with the presence of mutations (P = 0.013), and the absence of expression was associated with nuclear grade and the presence of metastasis (P<0.05). HIF-1alpha was negative in only 5 cases. Vascular endothelial growth factor (VEGF) was positive in 31 of 47 cases and was associated with Fuhrman nuclear grade, presence of metastasis, and stage (P<0.05). ERK5 expression was increased in 58% of cases and associated with the presence of metastasis and more advanced stages (P<0.05). In the logistic regression analysis, the only variable remaining in the model was VEGF expression (P = 0.014). ConclusionsVEGF has prognostic value in clear cell renal cell carcinoma, and ERK5 may be a new prognostic marker in this type of tumor owing to its relationship with metastasis and more advanced stages.

Effects of Echinomycin on PCNA-Dependent Follicular Development in PMSG-Induced Sprague-Dawley Rats

Echinomycin (Ech) is a small-molecule inhibitor of hypoxia-inducible factor-1 DNA-binding activity, which plays a crucial role in the regulation of ovarian functions in mammals. The present study was designed to test the hypothesis that hypoxia-inducible factor (HIF)-1alpha-mediated proliferation cell nuclear antigen (PCNA) expressions contributed to the follicular development in the rat ovary primed by pregnant mare serum gonadotropin (PMSG). Through the histological examination, the decrease of growing and antral follicle numbers was found after Ech treatment both in control and PMSG treated groups. And then PCNA mRNA and protein expressions were found to significantly increase in the ovaries treated with PMSG, and the similar changes were found in HIF-1alpha mRNA and protein expressions, indicating PMSG-induced follicular development may be through HIF-1alpha/PCNA signaling. Furthermore, PCNA expression was found to significantly decrease in the ovaries after Ech treatment, while HIF-1alpha mRNA and protein expression was no obviously changes. Further analysis found the changes of PCNA expression were consistent with HIF-1 activity in the ovaries, further suggesting the regulatory roles in the follicular development. Taken together, these results demonstrated this HIF-1alpha-mediated PCNA expression is one of the important mechanisms regulating the ovarian follicular development in mammals. Keywords: HIF-1alpha; PCNA; echinomycin; HIF prolyl hyodroxylase acitvity; follicular development

The Role of Hypoxia-Inducible Factor 1α in Allergic Rhinitis

Hypoxia-inducible factor (HIF) 1alpha is expressed under hypoxic conditions and plays an important role in immune and inflammatory responses. The role of HIF-1alpha in allergic airways has been investigated mainly in bronchial asthma. This study investigated the role of HIF-1alpha in mouse models and patients with allergic rhinitis (AR). Balb/c mice were sensitized with ovalbumin (OVA) and alum and were challenged intranasally with OVA. The HIF-1alpha inhibitor, 2-methoxyestradiol (2-ME), was administered intraperitoneally and multiple parameters of allergic responses were evaluated. HIF-1alpha and vascular endothelial growth factor (VEGF) mRNA and protein expression were also evaluated in patients with AR and a correlation analysis between mRNA expression and allergic symptoms was performed. In mouse models, the HIF-1alpha inhibitor 2-ME reduced allergic symptoms and eosinophilic infiltration into the nasal mucosa. 2-ME was found to suppress IgE production and inhibit local Th2 cytokine transcription in the nasal mucosa and systemic Th2 cytokine production by splenocytes. 2-ME also decreased HIF-1 and VEGF expression in nasal mucosa. An increase in HIF-1alpha and VEGF expression in the nasal mucosa of patients with AR was also observed. Our data suggest that HIF-1alpha plays an important role in mouse models and patients with AR. HIF-1alpha inhibitors induce antiallergic effects by decreasing both local and systemic Th2 cytokine (IL-4 and IL-5) production, IgE production, and eosinophil infiltration into the nasal mucosa in an AR model. HIF-1alpha and VEGF expression increased in the nasal mucosa of patients with AR, showing the role of HIF-1alpha in disease pathogenesis.

Фенотипические особенности экспрессии фактора, индуцированного гипоксией, и редокс-статус клеток неокортекса крыс на разных стадиях адаптации к гипоксии

Hypoxic preconditioning induces two-phase increase of HIF-1alpha expression in the neocortex of low-resistance rats. The first, brief phase appears after each hypoxic episode and rapidly disappears in normoxic conditions. The second increase in of HIF-1alpha expression occurs in 24 hours after the hypoxic episode. The phase-nature of HIF-1alpha expression corresponds to the dynamics of urgent and long-term resistance in low-resistance rats, which suggests the HIF-1alpha involvement in mechanisms of urgent and long-term adaptation. It was found that in the mode of preconditioning, hypoxic treatments mobilized the anti-oxidant system (activated Cu, Zn-SOD) and had no effect on the intensity of lipid peroxidation processes in neocortex (INH, 10% O2) or even decreased the content of lipid peroxidation products and oxidized glutathione in neocortical cells in the early post-hypoxic period (HBH-5000, 10.5% O2). Thus, ROS do not play a key role in the induction of HIF-1alpha expression and fast-response/long-term adaptation to O2 deficiency in hypoxia-sensitive animals. In high-resistance rats, hypoxia preconditioning does not influence the HIF-1alpha protein expression and the adaptation. Severe hypoxic modes (HBH-7000, 8% O2) caused activation of lipid peroxidation processes in neocortex of hypoxia-sensitive rats. With the pro-oxidant systems dominating over the anti-oxidant ones, the neocortical expression of HIF-1alpha was found to decrease, which was accompanied by the impairment of the mechanisms of fast-response/long-term adaptation to hypoxia.

Mucins 1‐shRNA inhibit the proliferation and HIF‐1alpha protein expression on human cholangiocarcinoma cells

To explore the effects of Mucins (MUC)1-shRNA on the proliferation and hypoxia inducible factor (HIF)-1alpha expression of human cholangiocarcinoma (CCA) QBC939 cells in vitro. MUC1-shRNA was constructed and transfected with Lipofectamine™ 2000 into cultured CCA cells. MUC1 mRNA and protein expression levels were determined by RT-PCR and Western blot, respectively. The cellular proliferation and HIF-1alpha expression of QBC939 cells were evaluated by the MTT assay and Western blot, respectively. After transfection, the expression levels of MUC1 mRNA and protein in the experimental group decreased significantly in QBC939 (P < 0.01). The proliferation of MUC1 shRNA-transfected group was 0.30 ± 0.05, 38.32 ± 1.43%, 15.18 ± 1.32%, and there were remarkable differences when compared with the control groups (P < 0.05). Significant inhibition of HIF-1alpha protein expression in MUC1 shRNA-transfected group was also discovered (P < 0.05). MUC1-shRNA could inhibit proliferation and significantly weaken HIF-1alpha protein expression of QBC939 cells, suggesting its potential as a therapeutic target of CCA.

Abstract 244: Vascular Induction of Adam17 in vitro and in Vivo By Angiotensin Ii: Potential Involvement of a Hypoxia Responsible Element

ADAM17 has been shown to play critical roles in angiotensin II (AngII)-dependent as well as independent types of pathophysiological vascular remodeling in vitro and in vivo. Enzymatic activation of ADAM17 by AngII has been described, however, little is known regarding regulation of ADAM17 protein expression in the cardiovascular system. Here we test our hypothesis that AngII induces ADAM17 protein expression to originate a feed forward loop of ADAM17 activation/induction in the vasculature. 8 week old control mice were infused with 1000 ng/kg/min AngII for 2 weeks via osmotic minipump. Serum starved rat VSMCs were stimulated with 100 nM AngII. ADAM17 expression was evaluated by immunohistochemistry and immunoblotting, respectively. In AngII-infused mice, marked ADAM17 induction was seen in vasculatures in heart and kidney, and carotid arteries and aortae. In VSMCs, AngII as well as PDGF-BB (50 ng/mL) time-dependently induced ADAM17 expression up to 24 hours (AngII 24h: 2.34±0.25 fold induction). Both AngII and PDGF-BB also stimulated ADAM17 promoter activity in VSMCs (AngII 24h: 2.90±0.17 fold induction). The ADAM17 promoter contains 6 typical hypoxia responsible elements (HREs). By using deletion and mutation constructs, the PDGF-BB response seems to require HRE4 located between -991 to -410 of the promoter. AngII-induced promoter activation was also lost in the HRE4 mutant. Moreover, both AngII and PDGF-BB stimulated HIF-1alpha protein expression in VSMCs at 4-8 hours. From these data, we conclude that AngII and PDGF induce ADAM17 expression in VSMCs via HIF1alpha/HRE-dependent transcriptional upregulation. The induction of ADAM17 via the HIF1/HRE-dependent mechanism likely promotes a feed-forward loop of ADAM17 activation/induction under a variety of pathophysiological conditions including hypoxia/ischemia leading to end organ damages in the cardiovascular system.

Effect of Danshensu on redox state and relevant nuclear transcription factors in non-small cell lung cancer A549 cells

To study the molecular mechanism of anti-tumor effect of Danshensu (DSS) focusing on whether it is related to its antioxidation effect on redox state of non-small cell lung cancer A549 cells and relevant nuclear transcription factors and signal pathway. DPPH radical scavenging, ferric reducing, ferrous iron chelating assay and DCFH-DA fluorescence staining of ROS were introduced to detect antioxidant activity and ROS scavenging activity in vitro; MTf was adopted to analyze the effect of DSS on A549 cells viability at different time and dose. Western blot was used to detect the effect of DSS on the protein expression of hypoxiainducible factor HIF-1alpha and redox regulating transcription factor Nrf2 in A549 cells and the phosphorylation of upstream Akt, ERK1/2 MAPK. DSS could reduce the ROS level in A549 cells in a dose-dependent manner, which was related to it's strong DPPH radical scavenging activity. Moreover, DSS inhibited A549 cells proliferation in both dose- and time- dependent manner. Further study on molecular mechanism indicated that DSS suppressed redox regulator Nrf2, and down-regulated the phosphorylation of Akt and ERK1/2. However, DSS had no effect on HIF-la expression. DSS might have the effect on treating non-small cell lung cancer by scavenging ROS and then inhibiting phosphorylation of Akt, ERK1/2 and down-regulating Nrf2 expression in A549 cells.

Hypoxia suppresses E-cadherin and enhances matrix metalloproteinase-2 expression favoring esophageal carcinoma migration and invasion via hypoxia inducible factor-1 alpha activation

The goal of this study was to explore the molecular mechanism of hypoxia inducible factor-1 alpha (HIF-1 alpha) action on migration and invasion of esophageal carcinoma cells. We used cobalt chloride (CoCl(2) ) to mimic tumor hypoxic microenvironment and analyzed the expressions of E-cadherin, matrix metalloproteinase-2 (MMP-2), and HIF-1 alpha in esophageal carcinoma cells under hypoxia by reverse transcription polymerase chain reaction and Western blotting. To analyze the function of HIF-1 alpha in Eca109 and TE1 cells, we established stable HIF-1 alpha knockdown cells using small interfering RNA. Blocking effect was detected by Western blotting. The concentrations of MMP-2 protein in the conditioned medium were also determined by enzyme-linked immunosorbent assay. Wound-healing and cell invasion assay were used to evaluate the migration and invasion of esophageal carcinoma cells. After exposure to hypoxia, expressions of HIF-1 alpha protein in Eca109 and TE1 cells were upregulated, both mRNA and protein levels of E-cadherin were downregulated, and MMP-2 were upregulated (P < 0.05), whereas HIF-1 alpha mRNA had no significant change (P > 0.05). Small interfering RNA could block HIF-1 alpha effectively under hypoxia, then enhanced E-cadherin expression and inhibited MMP-2 expression, respectively. Furthermore, expression of HIF-1 alpha protein was stable even though MMP-2 repressed by BB2516. Compared with that in normoxia, Snail expression was enhanced when Eca109 or TE1 cells exposed to hypoxia. Once HIF-1 alpha blocked, Snail expressions were inhibited accordingly. Wound recovery and the number of invading cells decreased (P < 0.05) after HIF-1 alpha blocked. The hypoxia suppresses E-cadherin expression and enhances MMP-2 expression favoring esophageal carcinoma migration and invasion via HIF-1 alpha activation. Our observations suggest that HIF-1 alpha inhibition might be an effective strategy to weaken the migration and invasion of esophageal carcinoma cells.

Association of hypoxia inducible factor-1α polymorphisms with susceptibility to non–small-cell lung cancer

Hypoxia-inducible factor-1α (HIF-1α) is a key regulator of cellular response to hypoxia and has been suggested to play an important role in tumorigenesis and metastasis. The aim of this study was to investigate the role of HIF-1α-1772 C/T (P582S) and -1790 G/A (A588T) polymorphisms in the susceptibility to and severity of non-small-cell lung cancer (NSCLC). Using a case-control study design and polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) analysis, the allele frequencies and genotype distributions of each single nucleotide polymorphism in 285 NSCLC cases and 300 gender-matched controls were compared. The distribution of the genotype frequencies of HIF-1α-1772 C/T and -1790 G/A were significantly different between the NSCLC and the controls. Logistic regression analysis revealed that higher odds ratios (ORs) for lung cancer were observed for individuals with HIF-1α-1772 T/T genotype against CC/CT genotypes (an OR of 4.04, 95% confidence interval [CI] = 2.02-8.08, P = 0.0001), and HIF-1α-1790 A/A genotype against GG/GA genotypes (an OR of 4.42, 95% CI 2.22-8.78, P < 0.0001). There were no relationship between HIF-1α-1772 C/T or -1790 G/A allele distribution and disease severity of NSCLC (P > 0.05). However, those patients carrying a HIF-1α-1772 T/T genotype or a HIF-1α-1790 A/A had a tendency toward inferior prognosis compared with other patients.

Effects of HCV core protein on the expression of hypoxia-inducible factor 1 alpha and vascular endothelial growth factor

To investigate the effect of core protein of hepatitis C virus (HCV) on the expression of hypoxia-inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF). Huh7.5.1 cells were transfected with plasmid flag2B-core carrying HCV core gene, expression of HIF-1alpha and VEGF were measured by reverse transcription-polymorphism chain reaction (RT-PCR) and western blot. Enzyme link immunoabsorbent assay (ELISA) were used to detect the level of VEGF in the supernatants. The expression of HIF-1alpha and VEGF mRNA and protein were upregulated after flag2B-core was transfected into Huh7.5.1 cells, and VEGF level in the supernatant was significant elevated as compared to controls [(654.5+/-43.7) pg/ml vs (365.9+/-26.8) pg/ml, t = 653.1%, P less than 0.01]. The expression of HIF-1alpha and VEGF mRNA and protein were downregulated after flag2B-core and HIF-1alpha siRNA were co-transfected into Huh7.5.1 cells, and VEGF level in the supernatant was significantly reduced as compared to controls [(389.2+/-29.6) pg/ml vs (768.8+/-47.3)pg/ml, t = 1330.22, P less than 0.01]. HCV core protein enhances the expression of HIF-1alpha and VEGF. HCV may regulate the expression of HIF-1alpha and VEGF via the core protein.

Abstract 3491: Chromosome 14q loss leads to haploinssuficiency of HIF-1a and poor outcomes in metastatic clear cell renal cell carcinoma

Abstract Purpose – One of the current key dilemmas in the management of metastatic renal cell carcinoma (mRCC) is the manifestation of innate or acquired resistance to anti-angiogenic therapy. Currently there are no biomarkers of therapeutic efficacy for antiangiogenic agents in clear cell renal cell carcinoma (ccRCC). Loss of chromosomal arm 14q has been previously associated with poor outcomes in surgically treated patients. We evaluated the association between 14q loss and therapeutic resistance in metastatic ccRCC (mRCC) and explored the role of candidate effector genes on this chromosome. Experimental Design – DNA from archival FFPE tumor specimens from 56 mRCC patients treated with sorafenib or bevacizumab was analyzed with Affymetrix 250K Nsp SNP microarrays. We identified the presence of genomic imbalances focusing on the presence of 14q loss. We then evaluated candidate genes in chromosome 14 by qPCR and immunohistochemistry (IHC) in the bevacizumab treated cohort. Results – 14q loss showed a significant association with worse response (SDPD vs. CRPR) in bevacizumab cohort (Fisher's exact test, p=0.0473), and with shorter progression free survival (PFS) in the sorafenib cohort (p=0.0318). HIF1A mRNA expression was significantly reduced in specimens with loss of 14q and was associated with PFS in the bevacizumab treated cohort (p=0.045). HIF-1alpha protein expression was also reduced in samples with 14q loss. Conclusions – Our studies demonstrate an association between a specific chromosomal alteration (14q loss) and clinical outcome in patients with advanced renal cell carcinoma treated with antiangiogenic agents. Loss of 14q was also associated to changes in the expression of HIF1A. Low HIF1A expression was strongly correlated with shorter PFS. We hypothesize that loss of 14q could lead to an imbalance in HIF-1α/HIF-2α activity, leading to increased HIF-2α, which has been shown to improve tumor cell viability by upregulating various pro-survival pathways. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3491. doi:10.1158/1538-7445.AM2011-3491

Chromosome 14q imbalances and pathways associated with resistance to antiangiogenic therapy in clear cell renal cell carcinoma.

339 Background: Antiangiogenic agents are used to treat metastatic clear cell renal cell carcinoma (ccRCC). Currently there are no biomarkers of therapeutic efficacy for these agents. Hypoxia inducible factor (HIF) alpha ratios have been linked to phenotypically distinct ccRCC subpopulations. The HIF1 alpha gene is located on chromosome 14q. In this study, the goal was to determine whether chromosomal imbalances identified with SNP arrays are linked to HIF ratios, and to clinical outcome. Methods: We obtained archival FFPE tumor specimens from 56 patients with mRCC treated with sorafenib or bevacizumab. DNA from the FFPE blocks was analyzed with Affymetrix 250K Nsp SNP microarrays. We identified the presence of genomic imbalances and loss of heterozygosity (LOH) to obtain virtual karyotypes. We then evaluated candidate genes in gain/lost chromosomal regions by qPCR and immunohistochemistry (IHC) in the bevacizumab treated specimens. Results: In the bevacizumab cohort, HIF1-alpha containing14q loss showed a significant association with worse response to treatment (CR/ PR vs. SD/PD, Fisher exact test, p = 0.0473). In addition, HIF1A mRNA expression was significantly reduced in all samples with 14q loss and was associated with PFS (HR = 2.29, 95% CI = 1.01-5.16, p = 0.045). HIF-1alpha protein expression was also reduced in samples with 14q loss. Conclusions: Chromosomal imbalances are associated with outcomes in ccRCC patients treated with antiangiogenic agents, and can lead to changes in gene expression. Low HIF1A expression was strongly correlated with shorter PFS. We hypothesize that loss of 14q could lead to an imbalance in HIF-1alpha/HIF-2alpha activity, leading to increased HIF-2alpha and enhanced c-Myc expression, which improves tumor cell viability and engenders resistance to cellular stress induced by antiangiogenic therapy. No significant financial relationships to disclose.

Rb1 postconditioning attenuates liver warm ischemia–reperfusion injury through ROS-NO-HIF pathway

AimsGinsenoside Rb1 could prevent ischemic neuronal death and focal cerebral ischemia, but its roles to liver warm I/R injury remain to be defined. We determined if Rb1 would attenuate warm I/R injury in mice. Main methodsMice were divided into sham, I/R, Rb1+I/R (Rb1 postconditioning, 20mg/kg, i.p. after ischemia), sham+L-NAME, I/R+L-NAME, and Rb1+I/R+L-NAME groups using 60min of the liver median and left lateral lobes ischemia. Serum levels of alanine aminotransferase (ALT) were measured and morphology changes of livers were evaluated. Contents of nitric oxide (NO) and nitric oxide synthase (NOS), malondialdehye (MDA) and activity of superoxide dismutase (SOD) were measured. Expressions of Akt, p-Akt, iNOS, HIF-1alpha, tumor necrosis factor-a (TNF-α) and intercellular adhesion molecule-1 (ICAM-1) were also determined by western blot or immunohistochemistry. Key findingsRb1 postconditioning attenuated the dramatically functional and morphological injuries. The levels of ALT were significantly reduced in Rb1 group (p<0.05). Rb1 upregulated the concentrations of NO, iNOS in serum, iNOS, and activity of SOD in hepatic tissues (p<0.05), while it dramatically reduced the concentration of MDA (p<0.05). Protein expressions of p-Akt, iNOS and HIF-1alpha were markedly enhanced in Rb1 group. Protein and mRNA expressions of TNF-α and ICAM-1 were markedly suppressed by Rb1 (p<0.05). SignificanceWe found that Rb1 postconditioning could protect liver from I/R injury by upregulating the content of NO and NOS, and also HIF-1alpha protein expression. These protective effects could be abolished by L-NAME. These findings suggested Rb1 may have the therapeutic potential through ROS-NO-HIF pathway for management of liver warm I/R injury.

Increased Expression of Hypoxia-Inducible Factor 1α in Coeliac Disease

Previously, it has been suggested that hypoxia-inducible factor (HIF) 1 signaling may play determinative role in the maintenance of the barrier function of the intestinal epithelium in inflammatory bowel disease. Our aim was to depict the alteration of HIF-1alpha and related genes in celiac disease (CD) where the importance of the barrier function is well known. Duodenal biopsy specimens were collected from 16 children with untreated CD, 9 children with treated CD and 10 controls. HIF-1alpha, trefoil factor 1 (TFF1), ecto-5-prime nucleotidase (CD73), and multi drug resistance gene 1 (MDR1) mRNA and HIF-1alpha protein expression were determined by real-time PCR and Western blot, respectively. Localization of HIF-1alpha was determined by immunofluorescent staining. We found increased HIF-1alpha and TFF1 mRNA and HIF-1alpha protein expression in the duodenal mucosa of children with untreated CD compared with controls or children with treated CD (p < 0.05). In untreated CD children, HIF-1alpha staining was present in cytoplasmic and nuclear region of the villous enterocytes. In treated CD mRNA expression of CD73 and MDR1 were increased compared with controls (p < 0.01 and 0.05, respectively). Our results of increased mucosal HIF-1alpha expression in CD children suggest the contribution of this signaling pathway in the pathomechanism of CD.