Hypoxia-inducible factor-1alpha gene polymorphisms and cancer risk: a meta-analysis

Exploring Genetic Link of Residual Ridge Resorption in Completely Edentulous Individuals: A Prospective Case-Control Clinical Study

BACKGROUND

Residual ridge resorption presents obstacles in prosthodontic treatment, affecting denture stability and the success of dental implants. Genetic elements, specifically the single nucleotide polymorphism (SNP) 1772C>T variant within the hypoxia-inducible factor 1 subunit alpha (HIF-1α) gene, are hypothesized to contribute to residual ridge resorption progression. Nevertheless, its impact remains insufficiently investigated, especially within the context of South Indian populations. We sought to investigate the connection between SNP 1772C>T and residual ridge resorption (RRR) among fully edentulous individuals, considering demographic factors, genotyping methodologies, and statistical evaluations.

METHODS

In a prospective case-control study, we recruited 100 completely edentulous participants from South India. Participants were categorized based on alveolar ridge height. Saliva samples were non-invasively collected for DNA extraction, and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was employed to determine genotype distribution using the HphI restriction enzyme. The statistical evaluations comprised the utilization of chi-square and Fisher's exact tests.

RESULTS

We observed no significant variations in genotype distributions between the case and control cohorts (CT: p=0.24; CC: p=0.65; TT: p=0.30). The heterozygous genotype CT was prevalent in both groups.

CONCLUSIONS

Although we did not observe significant associations between SNP 1772C>T and RRR, our findings imply a genetic predisposition to residual ridge resorption that warrants further exploration. Variations in genetic susceptibility across ethnicities and the influence of other genetic variants on residual ridge resorption require additional investigation. This study lays the groundwork for personalized prosthodontic care by highlighting the potential of genetic analysis in routine dental practice to improve treatment strategies.

Network pharmacology analysis, molecular docking integrated experimental verification reveal β-sitosterol as the active anti-NSCLC ingredient of Polygonatum cyrtonema Hua by suppression of PI3K/Akt/HIF-1α signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Polygonatum cyrtonema Hua (Huangjing) is a Chinese herb that is considered by ancient Chinese healers to have the effect of nourishing yin and moisturizing the lungs. It is clinically used to treat diseases of the pulmonary system, including non-small cell lung cancer. However, the precise active components and underlying mechanisms of Huangjing in the context of treating NSCLC remain uncertain.

AIM OF THE STUDY

This study aimed to explore the active components and mechanisms of Huangjing for the treatment of NSCLC by means of data mining, network pharmacology, and in vitro and vivo experiments.

MATERIALS AND METHODS

First, the main active compounds and key targets of Huangjing were predicted by network pharmacology. The potential key targets of Huangjing were molecularly docked with the main active compounds using Pymol. In vivo, we verified whether Huangjing and its main active compound have anti-lung cancer effects. Key targets were verified by PCR and immunohistochemistry. In vitro, we verified the effects of Huangjing's main active compound on the proliferation, apoptosis, and migration of A549 cells by CCK-8, colony formation, wound healing assay, and flow cytometry. Key targets and signaling pathway were validated by PCR and Western blot.

RESULTS

The network pharmacology results suggested that β-sitosterol was the main active substance. TP53, JUN, AKT1, MAPK14, ESR1, RELA, HIF1A, and RXRA were potential targets of Huangjing. Molecular docking results suggested that MAPK14, HIF-1α, and RXRA docked well with β-sitosterol. In vivo tests also confirmed that Huangjing could significantly inhibit the growth of lung cancer tumors, while PCR and immunohistochemistry results suggested that the expression of HIF-1α was significantly decreased. Critically, KEGG analysis indicated that the PI3K/Akt/HIF-1α signaling pathway was recommended as one of the main pathways related to the anti-NSCLC effect of Huangjing. We conducted in vitro experiments to confirm the significant impact of β-sitosterol on the proliferation, apoptosis, migration, and colony formation of A549 cells. Furthermore, our findings indicate that a high dosage of β-sitosterol may effectively decrease the expression of HIF-1α, AKT1, JUN and RELA in A549 cells. Similarly, in vitro experiments also revealed that high doses of β-sitosterol could inhibit the PI3K/Akt/HIF-1α signaling pathway.

CONCLUSIONS

We discovered Huangjing and its main active ingredient, β-sitosterol, can reduce HIF-1α, AKT1, JUN and RELA expression and decrease non-small cell lung cancer growth through the PI3K/Akt/HIF-1α signaling pathway.

Hypoxia-Inducible Factors-Based Single Nucleotide Polymorphism in Breast Cancer with More Cancer Susceptibility

Hypoxia-inducible factors (HIFs) are a collection of transcriptional factors that engage in the regulation of oxygen homeostasis. They are hypoxia-responsive stress factors whose expression is linked to tumor growth and angiogenesis. HIF is a crucial player in the progression of breast cancer. Patients with high levels of hypoxia-inducible HIFs in their primary tumor biopsies had a higher chance of metastasis, the leading cause of breast cancer-related death. HIF polymorphisms have been shown in several epidemiological studies to influence breast cancer susceptibility. In the oxygendependent degradation domain, several short nucleotide polymorphisms (SNPs) of the HIF gene have been connected with higher HIF activity. To find SNP that make up the genetic diversity that underpins the phenotypic difference found between individuals in their susceptibility to cancer and the course of their disease, researchers used a variety of potential pathway-based approaches.

Studies of the Anti-Diabetic Mechanism of Pueraria lobata Based on Metabolomics and Network Pharmacology

Diabetes mellitus (DM), as a chronic disease caused by insulin deficiency or using obstacles, is gradually becoming a principal worldwide health problem. Pueraria lobata is one of the traditional Chinese medicinal and edible plants, playing roles in improving the cardiovascular system, lowering blood sugar, anti-inflammation, anti-oxidation, and so on. Studies on the hypoglycemic effects of Pueraria lobata were also frequently reported. To determine the active ingredients and related targets of Pueraria lobata for DM, 256 metabolites were identified by LC/MS non targeted metabonomics, and 19 active ingredients interacting with 51 DM-related targets were screened. The results showed that puerarin, quercetin, genistein, daidzein, and other active ingredients in Pueraria lobata could participate in the AGE-RAGE signaling pathway, insulin resistance, HIF-1 signaling pathway, FoxO signaling pathway, and MAPK signaling pathway by acting on VEGFA, INS, INSR, IL-6, TNF and AKT1, and may regulate type 2 diabetes, inflammation, atherosis and diabetes complications, such as diabetic retinopathy, diabetic nephropathy, and diabetic cardiomyopathy.

Genetic Impact on Bone Modulation-A Review Bridging Bioscience to Genetic Engineering

Genes control approximately 60% to 75% of the variance of peak bone mass/density and a much smaller amount of variance in rate of loss.

Bone mass increases during growth to a peak value and soon after begins to decline. Most of the genetic effect is exerted during growth and so influences peak bone mass; whether there is an additional genetic effect on the rate of bone loss is less clear. So, this article aims to place emphasis on various oral and systemic conditions that are manifested due to altered gene function. Genetic polymorphisms and mutations are simple, although the consequences of the mechanism are complex. The syndromic manifestation due to changes at genetic level will greatly affect the bone quality, which will ultimately affect any treatment prognosis. Hence, a better understanding of molecular mechanisms of bone remodeling helps to identify pathogenic causes of bone, skeletal diseases, and leads to the development of targeted therapies for these diseases. This review highlights notions on the connecting link between science and genetics as well as various oral scenarios where gene could bring about changes, resulting in deformities. There is an intense research awaited in the future which could intervene with the causes that bring about genetic modulations, so as to decrease the mortality rate of humans.

The role of angiogenetic single-nucleotide polymorphisms in thymic malignancies and thymic benign lesions

Background

We previously showed that selected single-nucleotide-polymorphisms (SNPs) of genes involved in angiogenesis influence the aggressiveness of thymic epithelial tumors (TETs). This study analyzes their role in TETs and in thymic benign lesions, in order to investigate potential correlation with risk and outcome.

Methods

Genomic DNA was extracted from paraffin-embedded tissue of 92 patients, undergoing surgery at our Institution. We investigated by Real-Time PCR the SNPs of the following genes: platelet-derived growth factor receptor-α (PDGFRα), hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor A (VEGF-A), vascular endothelial growth factor receptor-2 and 3 (VEGF-2, VEGFR-3), excision repair cross-complementation group-1 (ERCC1).

Results

Fifty-seven TETs and 35 thymic benign lesions were included into the study. Frequency of SNPs was as follows: rs2057482 C, rs11158358 C and rs11549465 C polymorphisms of HIF1-a: thymomas < general population (P=0.008, P=0.007, and P=0.044 respectively). HIF1-a alleles: general population > study groups, rs1951795C SNP (P=0.026 for benign lesions and P=0.0007 for thymomas), rs10873142T SNP (P=0.008 and P=0.001 respectively), rs12434438 A SNP (P=0.034 and P=0.0007) and rs2301113A SNP (P=0.027 and P=0.010). rs699947C polymorphism of VEGF-A: benign lesions > general population (P=0.012).

Conclusions

This is the first study investigating the angiogenetic polymorphisms in thymic benign lesions and TETs. SNPs analysis may represent a further asset in identification of patients who could benefit from anti-angiogenetic therapy.

Different polymorphisms in HIF-1α may exhibit different effects on cancer risk in Asians: evidence from nearly forty thousand participants

The effect of different SNPs in HIF-1α and cancer susceptibility remain indistinct. Here, we evaluated the association between all identified SNPs (rs11549465, rs11549467 and rs2057482) in HIF-1α and the overall risk of cancer in all case-control studies published before April 2020. A total of 54 articles including 56 case-control studies were included in this analysis. We found that variant genotypes of rs11549465 and rs11549467 were associated with a significantly increased overall cancer risk. In contrast, the variant T allele of rs2057482 showed a significantly reduced risk of overall cancer. In addition, variant genotypes of the three studied SNPs exhibited a significant association with cancer risk in Asians and specific cancer types. Meanwhile, HIF-1α was significantly highly expressed in head and neck squamous cell carcinoma and pancreatic cancer tissues. More importantly, survival analysis indicated that the high expression of HIF-1α was associated with a poor survival in patients with lung cancer. These findings further provided evidence that different SNPs in HIF-1α may exhibit different effects on overall cancer risk; these effects were ethnicity and type-specific. Further studies with functional evaluations are required to confirm the biological mechanisms underlying the role of HIF-1α SNPs in cancer development and progression.

HIF-1α rs11549465 C>T polymorphism contributes to increased cancer susceptibility: Evidence from 49 studies

HIF-1α (hypoxia-inducible factor-1α) is a transcriptional factor that participates in the regulation of oxygen homeostasis. Despites numbers of case-control studies working on this area, the actual relationship of HIF-1α gene generic variant rs11549465 C>T imposing on cancer susceptibility remains unveiled. To get a better understanding of such relationship, this meta-analysis was carried out by incorporating all eligible case-control studies. Qualified articles were acquired from PubMed, CNKI, EMBASE, PMC, and Wanfang database update to April 2019. Odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were employed to estimate the relationship of interest. Heterogeneity tests, sensitivity analyses and publication bias assessments were also carried out to ensure the strength of our conclusion. A total of 46 articles with 49 studies including 12920 cases and 13363 controls were included. The results indicated that HIF-1α rs11549465 C>T was significantly related to the increased risk of overall cancer under four genetic models (TT vs. CC: OR=2.06, 95% CI=1.34-3.16; TT vs. CC/CT: OR=2.42, 95% CI=1.60-3.65; CT/TT vs. CC: OR=1.21, 95% CI=1.04-1.40; T vs. C: OR=1.29, 95% CI=1.12-1.48). Furthermore, enhanced cancer risk was detected after stratification by cancer type, ethnicity, the source of controls and HWE. These results suggest that HIF-1α rs11549465 C>T polymorphism may predispose to cancer susceptibility.

A Genetic Association Study of a Specific Gene and Severe Form of Resorption in the Edentulous Mandible in the Egyptian Population

PURPOSE

To investigate for the first time in Egypt and the Middle East the relationship between a specific gene and the presence of severely resorbed edentulous mandibular ridges in a sample of the Egyptian population.

MATERIALS AND METHODS

The study was conducted on 50 subjects divided into case and control groups according to the residual ridge height. Saliva was used as a convenient source of DNA in the dental clinic. A certain genetic variation (1772C>T) in an important gene related to bone healing (hypoxia-inducible factor-1 alpha [HIF1-α] gene) was selected. The genetic variation 1772C>T is a single nucleotide polymorphism (SNP) that occurs when corresponding sequences of DNA from different individuals differ at one base. Then, we have 2 forms of the gene (2 alleles): C and T. SNPs typically have 3 genotypes; in this study, they are the CC, CT, and TT genotypes. Polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) was the method performed for genotyping. The statistical significance of the results was evaluated by the Chi-square test and Fisher Exact test.

RESULTS

A statistically significant difference in the distribution of the TT genotype between both groups was detected with p-value = 0.049. There was also a difference in the distribution of the CC and CT genotypes, but it was not statistically significant, since the p-values were 0.733 and 0.145, respectively. The T alleles were more abundant in the case group, while the control group showed more frequency of the C allele with no statistical significance.

CONCLUSION

The TT genotype of the 1772C>T polymorphism of HIF1-α gene is related to the presence of severely atrophied residual ridges in completely edentulous Egyptians. This can be used as a marker to predict the future condition of the ridge using saliva samples. Further studies on larger scale are recommended.

HIF1A gene polymorphisms and human diseases: Graphical review of 97 association studies

Hypoxia-inducible factors (HIFs) belong to a family of transcription factors (TF) responsive to a low O2 availability, which is often a characteristic feature of solid tumors. The alpha subunit of the HIF heterodimer is O2 -sensitive, and once stabilized in hypoxia, it functions as a master regulator of various genes involved in hypoxia pathway. Changes in the HIF1A (hypoxia inducible factor 1, alpha subunit) nucleotide sequence or expression has been shown to be associated with the development of several diseases. Because of increasing research interest in HIF1A gene a review of association studies was needed. We here reviewed published data on single nucleotide polymorphisms (SNPs) in HIF1A in various diseases; in total, 34 SNPs were tested for an association with 49 phenotypes, and the results were visualized using the Cytoscape software. Among all collected polymorphisms 16 SNPs showed significant associations with 40 different phenotypes, including six SNPs associated with 14 cancer types. Missense SNPs (rs11549465 and rs11549467) within the oxygen-dependent degradation domain were most frequently studied. The study provides a comprehensive tool for researchers working in this area and may contribute to more accurate disease diagnosis and identification of therapeutic targets.

Hypoxia and renal cell carcinoma: The influence of HIF1A+1772C/T functional genetic polymorphism on prognosis

OBJECTIVES

Hypoxia-inducible factor (HIF-1) is a key regulator of the genes involved in the cellular response to hypoxia. Overexpression of HIF-1 has been implicated in the pathogenesis of renal cell carcinoma (RCC), and functional polymorphisms of the HIF1A gene may confer susceptibility to RCC. Our purpose was to assess the influence of HIF1A+1772C/T (rs11549465) polymorphism on RCC prognosis.

MATERIAL AND METHODS

This study evaluated the associations of the HIF1A+1772C/T (rs11549465) polymorphism with clinicopathologic prognostic factors, recurrence/progression, and survival in a cohort of 179 patients with RCC treated at Portuguese Oncology Institute of Porto. Genotyping analysis, using DNA extracted from peripheral blood, was performed by real-time polymerase chain reaction allelic discrimination. The genotype associations with clinicopathologic parameters and recurrence/progression were analyzed by the chi-square or Fisher tests. Genotypes influencing cancer-specific survival were compared using Cox proportional hazard regression, Kaplan-Meier curves, and Breslow test.

RESULTS

None of the genotypes (CC, CT, or TT) were significantly associated with clinicopathologic prognostic factors. The TT genotype and T allele were associated with recurrence/progression (P = 0.042 and P = 0.02, respectively). Patients with CT and CT+TT genotypes tend to have an increased risk to RCC-related death (hazard ratio = 2.79; 95% CI: 0.88-8.82; P = 0.08 and hazard ratio = 2.76; 95% CI: 0.93-8.22; P = 0.07, respectively) and showed worse cancer-specific survival curves than those with the CC genotype (P = 0.012 and P = 0.018, respectively).

CONCLUSIONS

These results suggest that HIF1A+1772C/T (rs11549465) polymorphism may have effects on RCC recurrence/progression and survival.

Che-1 sustains hypoxic response of colorectal cancer cells by affecting Hif-1α stabilization

Background

Solid tumours are less oxygenated than normal tissues. Consequently, cancer cells acquire to be adapted to a hypoxic environment. The poor oxygenation of solid tumours is also a major indicator of an adverse cancer prognosis and leads to resistance to conventional anticancer treatments. We previously showed the involvement of Che-1/AATF (Che-1) in cancer cell survival under stress conditions. Herein we hypothesized that Che-1 plays a role in the response of cancer cells to hypoxia.

Methods

The human colon adenocarcinoma HCT116 and HT29 cell lines undepleted or depleted for Che-1 expression by siRNA, were treated under normoxic and hypoxic conditions to perform studies regarding the role of this protein in metabolic adaptation and cell proliferation. Che-1 expression was detected using western blot assays; cell metabolism was assessed by NMR spectroscopy and functional assays. Additional molecular studies were performed by RNA seq, qRT-PCR and ChIP analyses.

Results

Here we report that Che-1 expression is required for the adaptation of cells to hypoxia, playing an important role in metabolic modulation. Indeed, Che-1 depletion impacted on HIF-1α stabilization, thus downregulating the expression of several genes involved in the response to hypoxia and affecting glucose metabolism.

Conclusions

We show that Che-1 a novel player in the regulation of HIF-1α in response to hypoxia. Notably, we found that Che-1 is required for SIAH-2 expression, a member of E3 ubiquitin ligase family that is involved in the degradation of the hydroxylase PHD3, the master regulator of HIF-1α stability.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-017-0497-1) contains supplementary material, which is available to authorized users.

Genetic polymorphisms in key hypoxia-regulated downstream molecules and phenotypic correlation in prostate cancer

Background

In this study we sought if, in their quest to handle hypoxia, prostate tumors express target hypoxia-associated molecules and their correlation with putative functional genetic polymorphisms.

Methods

Representative areas of prostate carcinoma (n = 51) and of nodular prostate hyperplasia (n = 20) were analysed for hypoxia-inducible factor 1 alpha (HIF-1α), carbonic anhydrase IX (CAIX), lysyl oxidase (LOX) and vascular endothelial growth factor (VEGFR2) immunohistochemistry expression using a tissue microarray. DNA was isolated from peripheral blood and used to genotype functional polymorphisms at the corresponding genes (HIF1A +1772 C > T, rs11549465; CA9 + 201 A > G; rs2071676; LOX +473 G > A, rs1800449; KDR – 604 T > C, rs2071559).

Results

Immunohistochemistry analyses disclosed predominance of positive CAIX and VEGFR2 expression in epithelial cells of prostate carcinomas compared to nodular prostate hyperplasia (P = 0.043 and P = 0.035, respectively). In addition, the VEGFR2 expression score in prostate epithelial cells was higher in organ-confined and extra prostatic carcinoma compared to nodular prostate hyperplasia (P = 0.031 and P = 0.004, respectively). Notably, for LOX protein the immunoreactivity score was significantly higher in organ-confined carcinomas compared to nodular prostate hyperplasia (P = 0.015). The genotype-phenotype analyses showed higher LOX staining intensity for carriers of the homozygous LOX +473 G-allele (P = 0.011). Still, carriers of the KDR−604 T-allele were more prone to have higher VEGFR2 expression in prostate epithelial cells (P < 0.006).

Conclusions

Protein expression of hypoxia markers (VEGFR2, CAIX and LOX) on prostate epithelial cells was different between malignant and benign prostate disease. Two genetic polymorphisms (LOX +473 G > A and KDR−604 T > C) were correlated with protein level, accounting for a potential gene-environment effect in the activation of hypoxia-driven pathways in prostate carcinoma. Further research in larger series is warranted to validate present findings.

Electronic supplementary material

The online version of this article (doi:10.1186/s12894-017-0201-y) contains supplementary material, which is available to authorized users.

Role of exon 7 PTEN Gene in Endometrial Carcinoma

BACKGROUND

Endometrial carcinoma is the most common malignant tumor of the female genital tract and the fourth most common cancer in Iranian women after breast, colorectal and lung cancers. Various genetic alterations appear to be early events in the pathogenesis of endometrial carcinoma and it seems that PTEN is the most commonly mutated gene in the endometrioid subtype. The aim of the present study was to investigate the correlation between mutations in exon 7 of PTEN gene and endometrial carcinoma.

MATERIALS AND METHODS

Seventy-five patients with endometrial carcinoma and 75 females whose underwent hysterectomy for non tumoral indication were selected for evaluation of PTEN mutations in exon 7 by PCR-SSCP and sequencing. Correlations between the frequency and type of mutation and the pathologic findings of the cancer (tumor subtype, stage and grade) were assessed.

RESULTS

All of the samples were obtained from Iranian patients. 60 % (45 cases) of the tumors were endometriod and 40% (30 cases) were of serous type. The grade distributions of the 75 cases according to the FIGO staging system were as follows: low grade, 20 cases; high grade 55 cases, low stage, 41 cases; high stage 34 cases. For exon 7 of the PTEN gene, the analysis showed that there were no mutations in our cases.

CONCLUSIONS

Our findings in the present study suggest that exon 7 of PTEN does not play any significant role in the development of endometrial carcinoma in Iranian cases.

Vascular endothelial growth factor pathway in endometriosis: genetic variants and plasma biomarkers

OBJECTIVE

To study single nucleotide polymorphisms (SNPs) involved in angiogenesis (VEGF, PLGF, VEGFR1, VEGFR2, HIF-1α) and plasma levels of the corresponding proteins (VEGF, PLGF, sVEGFR1, sVEGFR2) in women with and without endometriosis.

DESIGN

Allele frequencies of vascular endothelial growth factor (VEGF) pathway SNPs and plasma levels of the corresponding proteins were investigated in patients with endometriosis and in controls.

SETTING

University hospital.

PATIENT(S)

Samples of DNA from 1,931 Caucasian patients were included (1,109 patients with endometriosis and 822 controls). An additional study group included 973 DNA samples from volunteers, self-reported to be healthy without laparoscopic evaluation.

INTERVENTION(S)

Women who underwent a laparoscopy for subfertility and/or pain and healthy volunteers without laparoscopic evaluation.

MAIN OUTCOME MEASURE(S)

Functional SNPs of the VEGF, VEGFR1, VEGFR2, HIF-1α genes and Hap Map tagging SNPs of the PLGF gene were genotyped by using iPLEX technology on a Sequenom MassArray and TaqMan SNP Genotyping Assay. The VEGF levels were determined in ethylenediaminetetraacetic acid plasma samples by using Bio-Plex Protein Array System. PLGF, sVEGFR1, and sVEGFR2 levels were measured in ethylenediaminetetraacetic acid plasma samples by using ELISA Quantikine kits.

RESULT(S)

A significant association was found between the rs2268613 polymorphism in the PLGF gene and PLGF plasma levels. In all study subjects, women with the AA variant of the rs2268613 PLGF gene had significantly lower PLGF plasma levels (median [interquartile range] 9.36 [8.19-10.43] pg/mL) than those with the AG variant (12.1 [11.81-20.84] pg/mL; P(a)=.0085, P(b)=.04), both before and after multiple testing. Plasma levels of VEGF were elevated in endometriosis patients (especially in minimal-mild endometriosis during the menstrual cycle phase) compared with laparoscopic controls but had a moderate diagnostic performance (area under the curve, 0.73) in this discovery dataset. At a cut-off plasma level of VEGF >3.88 pg/mL, minimal-mild stages of endometriosis were diagnosed with a sensitivity of 74% and a specificity of 80% during the menstrual phase of cycle. The associations between the presence of endometriosis and SNPs in PLGF (rs2268614), HIF-1α (rs11549465), and VEGFR1 (rs9582036) genes lost statistical significance after multiple testing.

CONCLUSION(S)

Genetic variants in the PLGF rs2268613 gene may influence plasma levels of the corresponding protein. Plasma levels of VEGF were elevated in endometriosis patients compared with controls. The associations between the presence of endometriosis and SNPs in PLGF (rs2268614), HIF-1α (rs11549465), and VEGFR1 (rs9582036) genes lost statistical significance after multiple testing.

The polymorphism of hypoxia-inducible factor-1a gene in endometrial cancer

BACKGROUND

Endometral carcinoma is the most common malignant tumor of the female genital tract and the fourth most common cancer in women after breast, colorectal and lung cancers Hypoxia-inducible factor -1 (HIF-1) is a key transcription factor that regulates cellular response to hypoxia HIF-1 plays important roles in the development and progression of cancer through activation of various genes that are involved in crucial aspects of cancer biology, including angiogenesis, energy metabolism, vasomotor function, erythropoiesis, and cell survival. In this study, we aimed to investigate the association between HIF-1 1772 C/T polymorphisms and endometrial cancer.

MATERIALS AND METHODS

75 patients with endometrial carcinoma and 75 patients whose underwent hysterectomy for non tumoral indication selected for evaluation of HIF-1 1772 C/T polymorphisms by PCR-RFLP and sequencing.

RESULTS

For the 1772 C/T polymorphism, the analysis showed that the T allele and genotype TT were significantly associated with endometrial cancer risk.

CONCLUSIONS

Our results suggest that the C1772T polymorphism of the HIF-1a may be associated with endometrial cancers.

Impact of the hypoxia inducible factor-1α (HIF-1α) pro582ser polymorphism and its gene expression on diabetic foot ulcers

AIM

Adaptation to low oxygen tension (hypoxia) in cells and tissues leads to the transcriptional induction of series of genes and the primary factor mediating this response is the hypoxia-inducible factor-1α. This study was designed in order to examine the HIF-1α gene polymorphism, p582s (rs11549465) in Exon-12 of HIF-1α gene in diabetic subjects with and without foot ulcers (DFU) and to find its expression under these pathological conditions.

METHODS

A total of 224 subjects from our tertiary care centre were included, which consists of healthy controls (N=66), type 2 diabetes mellitus (T2DM) (N=79) and T2DM with foot ulcers (DFU) (N=79). Allelic and genotypic comparisons between the different groups were evaluated by PCR-RFLP. The gene expression studies on selected samples (N=15 of each group) were done by Semi-quantitative real time PCR.

RESULTS AND DISCUSSIONS

Genotype analysis showed a significant increase in presence of 'T' allele in T2DM & DFU when compared to that of control subjects. Allele wise analysis showed a higher frequency of 'T' allele in the T2DM (62.03%) when compared to that of control subjects (53.79%). Interestingly, semi-quantitative RT-PCR results showed decreased expression of HIF-1α gene on DFU when compared to that of T2DM and control subjects.

CONCLUSION

Our findings predict that there is an association of HIF-1α gene polymorphism on foot ulcer patients when compare to that of healthy controls. Semi-quantitative real time studies showed decreased HIF-1α gene expression on foot ulcer patients suggesting its possible role on the pathogenesis.

The association between the rs11549465 polymorphism in the hif-1α gene and cancer risk: a meta-analysis

PURPOSE

The associations between hypoxia-inducible factor-1 alpha (HIF-1alpha) and clinicopathological characteristics of cancers have been evaluated in various studies, with the conflicting results. The common rs11549465 (1772C/T) genetic polymorphism has been reported to be functional and may contribute to genetic susceptibility to cancers. However, the association between rs11549465 (1772C/T) and cancer risk remains inconclusive.

METHODS

To better understand the role of rs11549465 (1772C/T) polymorphism in global cancer, we conducted this comprehensive meta-analysis encompassing 7807 cases and 8633 controls.

RESULTS

Overall, the rs11549465 (1772C/T) genetic polymorphism was associated with higher cancer risk, especially exists in Asians. In the stratified analysis, significant associations were found between the HIF-1 rs11549465 polymorphism and gynecologic cancer among Caucasian population. We observed that the TT genotype might modulate gynecologic cancer (OR=9.92 [2.15-45.66]) risk comparing with the CC genotype. Moreover, a significantly increased lung and breast cancer risk was found among Asian population comparing with Caucasian population. When stratified by study design, significantly elevated susceptibility to cancer was found among hospital -based studies.

CONCLUSIONS

Our meta-analysis suggested that the HIF-1 rs11549465 (1772C/T) genetic polymorphism is significantly associated with higher risk among Asian population and lower risk among Caucasian population in breast and lung cancer, and this SNP was significantly associated with the gynecologic cancer among Caucasian population. The effect of the rs11549465 polymorphism on cancer especially exists in Asians.

Association between HIF-1α C1772T/G1790A polymorphisms and cancer susceptibility: an updated systematic review and meta-analysis based on 40 case-control studies

Background

HIF-1 (hypoxia-inducible factor 1) is a transcriptional activator that functions as a critical regulator of oxygen homeostasis. Recently, a large number of epidemiological studies have investigated the relationship between HIF-1α C1772T/G1790A polymorphisms and cancer susceptibility. However, the results remain inconclusive. Therefore, we performed a meta-analysis on all of the available case-control studies to systematically summarize the possible association.

Methods

A literature search was performed using PubMed and the Web of Science database to obtain relevant published studies. Pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for the relationship between HIF-1α C1772T/G1790A polymorphisms and cancer susceptibility were calculated using fixed- and random-effects models when appropriate. Heterogeneity tests, sensitivity analyses and publication bias assessments were also performed in our meta-analysis.

Results

A total of 40 studies met the inclusion criteria were included in the meta-analysis: 40 studies comprised of 10869 cases and 14289 controls for the HIF-1α C1772T polymorphism and 30 studies comprised of 7117 cases and 10442 controls for the HIF-1α G1790A polymorphism. The results demonstrated that there were significant association between the HIF-1α C1772T polymorphism and cancer susceptibility under four genetic models (TT vs. CC: OR = 1.63, 95% CI = 1.02-2.60; CT + TT vs. CC: OR = 1.15, 95% CI = 1.01-1.34; TT vs. CT + CC: OR = 2.11, 95% CI = 1.32-3.77; T vs. C: OR = 1.21, 95% CI = 1.04-1.41). Similarly, the statistically significant association between the HIF-1α G1790A polymorphism and cancer susceptibility was found to be consistently strong in all of the genetic models. Moreover, increased cancer risk was observed when the data were stratified by cancer type, ethnicity and the source of controls.

Conclusions

This meta-analysis demonstrates that both the C1772T and G1790A polymorphisms in the HIF-1α gene likely contribute to increased cancer susceptibility, especially in the Asian population and in breast cancer, lung cancer, pancreatic cancer and oral cancer. However, further research is necessary to evaluate the relationship between these polymorphisms and cancer risk.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-950) contains supplementary material, which is available to authorized users.

Variants in angiogenesis-related genes and the risk of clear cell renal cell carcinoma

Angiogenesis is fundamentally important to the pathogenesis of clear cell renal cell carcinoma (ccRCC). We investigated the association between variations of genes related to angiogenesis and the risk of ccRCC. In a case-control study of 859 ccRCC patients and 1004 cancer-free subjects, we genotyped 24 potentially functional single nucleotide polymorphisms (SNPs) in seven angiogenesis-related genes (HIF1A, EPAS1, VEGFA, VEGFR1, VEGFR2, VEGFR3 and PDGFRB) using the TaqMan or Snapshot method. Unconditional logistic regression, adjusted for potential confounding factors, was used to assess the risk associations. The functionality of selected SNPs was assessed by real-time quantitative reverse transcription polymerase chain reaction (RT-PCR) and luciferase reporter gene assays. We found two SNPs (VEGFA rs2010963 and VEGFR3 rs448012) that were significantly associated with increased risk of ccRCC, after adjusting for multiple comparisons [rs2010963 CC/GC cf. GG: false discovery rate (FDR) = 0.048, odds ratio (OR) = 1.36, 95% confidence interval (95% CI) = 1.12-1.66; rs448012 CC/GC cf. GG: FDR = 0.048, OR = 1.38, 95% CI =1.13-1.69]. Real-time quantitative PCR revealed that the variant genotypes of rs2010963, but not rs448012, were associated with increased gene expression in normal tissues of ccRCC patients (CC/GC cf. GG: P = 0.036). The luciferase reporter assay showed that the rs2010963 C allele significantly increased luciferase activity over that of the rs2010963 G allele. Our results indicate that VEGFA rs2010963 and VEGFR3 rs448012 are associated with risk of ccRCC. Furthermore, rs2010963 is a functional SNP that may affect ccRCC susceptibility by modulating endogenous VEGFA expression.

HIF-1α genetic variants and protein expression confer the susceptibility and prognosis of gliomas

To investigate the role of HIF-1α genetic polymorphism of c.1772C>T and c.1790G>A in the incidence and prognosis of gliomas in a Chinese cohort, a total of 387 gliomas patients and 437 age- and sex-matched healthy controls were recruited. The genetic polymorphism of c.1772C>T and c.1790G>A was determined. We found that the genotype distribution at c.1772C>T showed significant difference between patients and controls. Multivariable analyses showed a significantly higher risk for gliomas in 1772TT genotype carriers (odds ratio 2.68, with CC as reference). In addition, we also found a significantly higher risk for grade III + IV gliomas was observed in 1772TT genotype carriers (odds ratio 2.21, with CC as reference). The overall survival rates in patients with 1772TT or 1772CT genotype were markedly lower compared with patients with CC (both P < 0.01). Our in vitro studies revealed that HIF-1α regulates the proliferation, migration and invasion of human glioma U251 cells. This study suggests that the c.1772C>T polymorphisms may be used as a molecular marker for gliomas occurrence, grades and clinical outcome in gliomas patients.

The HIF1A rs2057482 polymorphism is associated with risk of developing premature coronary artery disease and with some metabolic and cardiovascular risk factors. The Genetics of Atherosclerotic Disease (GEA) Mexican Study

The aim of the present study was to establish the role of HIF1A gene polymorphisms in the risk of developing premature coronary artery disease (CAD) in a well-characterized clinical cohort. Three polymorphisms in HIF1A (rs11549465, rs11549467, rs2057482) gene were genotyped in 949 patients with premature CAD, and 676 healthy controls (with negative calcium score by computed tomography). Under a dominant model adjusted for age, visceral to subcutaneous adipose tissue (VAT/SAT) ratio, hypertension, type 2 diabetes mellitus (T2DM), HDL-C levels, hypercholesterolemia and hypertriglyceridemia, the rs2057482 T allele was associated with decreased risk of premature CAD when compared to healthy controls (OR = 0.616, P(dom) = 0.020). The effect of the studied polymorphisms on various metabolic parameters and cardiovascular risk factors was explored. In this analysis, the rs2057482 T allele was associated with decreased risk of obesity, central obesity, hypertension, hypercholesterolemia, hypertriglyceridemia and increased risk of T2DM. Under a dominant model adjusted by age, the HIF1A rs2057482 T polymorphism was associated with high VAT/SAT ratio (P = 0.009) and HDL-C levels (P = 0.04) in healthy controls. The results suggest that HIF1A rs2057482 polymorphism is involved in the risk of developing CAD and is associated with some metabolic parameters and cardiovascular risk factors.

Clinical and prognostic significance of HIF-1α, PTEN, CD44v6, and survivin for gastric cancer: a meta-analysis

Purpose

This study was to quantitatively summarize published data for evaluating the clinical and prognostic significance of four proteins involved in hypoxia-inducible factor-1 (HIF-1α) regulation of the metastasis cascade.

Methods

Searches were performed using the MEDLINE, EMBASE, Cochrane Library, and Chinese Biomedicine databases without any language restrictions. Studies were pooled and either the summary risk ratio (RR) or odds ratio (OR) was calculated. Potential sources of heterogeneity were sought out via subgroup and sensitivity analyses, and publication bias was also performed.

Results

Seventeen studies evaluated HIF-1α, 20 studies evaluated phosphatase and tensin homolog (PTEN), 20 studies evaluated Survivin, and 16 studies evaluated CD44v6. Our results showed that increased HIF-1α expression was linked to a poor 5-year overall survival (RR = 1.508; 95% confidence interval (CI) 1.318–1.725; P<0.001). Decreased survival was heavily influenced by advanced tumor invasion (OR = 3.050; 95% CI 2.067–4.501; P<0.001), lymph node metastasis (1415 patients; OR = 3.486, 95% CI 2.737–4.440; P<0.001), distant metastasis (OR = 6.635; 95% CI 1.855–23.738; P = 0.004), vascular invasion (OR = 2.368; 95% CI 1.725–3.252; P<0.001), dedifferentiation (OR = 2.112; 95% CI 1.410–3.163; P<0.001), tumor size (OR = 1.921; 95% CI 1.395–2.647; P<0.001), and a higher TNM stage (OR =  2.762; 95% CI 1.941–3.942; P<0.001). Similarly, aberrant expression of PTEN, CD44v6, and Survivin were also observed in tumors that correlated with poor OS. The higher ORs of death at 5 years were 1.637 (95% CI = 1.452–1.845; P<0.001), 1.901 (95% CI = 1.432–2.525; P<0.001), and 1.627 (95% CI = 1.384–1.913; P<0.001), respectively, with an OR>2 for the main stratified meta-analyses of clinical factors.

Conclusions

Our findings indicate that HIF-1α/PTEN/CD44v6/Survivin, as measured by immunohistochemistry, can be used to predict the prognosis and potential for invasion and metastasis in Asian patients with gastric cancer. The development of strategies against this subset of proteins could lead to new therapeutic approaches.

Prognostic role of hypoxic inducible factor expression in non-small cell lung cancer: a meta-analysis

INTRODUCTION

Reported prognostic roles of hypoxic inducible factor (HIF) expression in non-small cell lung cancer (NSCLC) have varied. This meta-analysis aimed to examine the relationship between HIF expression and clinical outcome in NSCLC patients.

METHODS

PubMed were used to identify relevant literature with the last report up to December 20th, 2012. After careful review, survival data were collected from eligible studies. We completed the meta-analysis using Stata statistical software (Version 11) and combined hazard ratio (HR) for overall survival (OS). Subgroup specificity, heterogeneity and publication bias were also assessed. All of the results were verified by two persons to ensure accuracy.

RESULTS

Eight studies were finally stepped into this meta-analysis in which seven had available data for HIF-1α and three for HIF-2α. Combined HRs suggested that higher expression of HIF1α had a negative impact on NSCLC patient survival (HR=1.50; 95%CI =1.07-2.10; p=0.019). The expression of HIF-2α was also relative to a poorer survival (HR=2.02; 95%CI =1.47-2.77; p=0.000). No bias existed in either of the two groups.

CONCLUSION

This study suggests that elevations of HIF-1α and HIF- 2α expression are both associated with poor outcome for patients with NSCLC. The data support further and high quality investigation of HIF expression for predicting poor outcome in patients with NSCLC.

Hypoxia-inducible factor-1α (HIF-1α) C1772T polymorphism significantly contributes to the risk of malignancy from a meta-analysis

Although the association between hypoxia-inducible factor-1α (HIF-1α) C1772T polymorphism and risk of malignancy has been widely studied, results from published studies remained controversial. Therefore, the relationship between them was further assessed in this meta-analysis. The databases of PubMed, Embase, and Wanfang were searched, and odds ratio with 95% confidence interval (OR and 95% CI) were used to assess the strength of the association. A total of 38 case-control studies with 23,876 participants were included. Overall, the T allele of HIF-1α C1772T was significantly associated with increased risk of malignancy development (OR and 95% CI 1.18 (1.00-1.38), P = 0.048 for T carriers vs. CC; 1.22 (1.05-1.41), P = 0.010 for T carriers vs. C carriers). When subgroup analyses were conducted, T allele was further found to be associated with increased risk of malignancy development for Asians rather than Caucasians (OR and 95% CI 1.36 (1.10-1.67), P = 0.004 for Asians) and for population-based studies (OR and 95% CI 1.19 (1.01-1.41), P = 0.040). Between-study heterogeneity existed in genetic comparison models, and meta-regression indicated that the participants' ethnicities and types of malignancy might be the sources of heterogeneity. No publication bias was found. In conclusion, this study indicated that HIF-1α C1772T polymorphism was significantly associated with increased risk of malignancy development for Asians. More studies were further required to focus on the relationship between HIF-1α C1772T polymorphism and risk of a specific type of tumor.

The association between hypoxia-inducible factor-1 α gene C1772T polymorphism and cancer risk: a meta-analysis of 37 case-control studies

Background

The possible association between HIF-1α C1772T polymorphism and cancer risk has been studied extensively. However, the results were controversial. In order to get a more precise conclusion of this association, a meta-analysis was performed.

Methods

A total of 10186 cases and 10926 controls in 37 case-control studies were included in this meta-analysis. Allele and genotypic differences between cases and controls were evaluated. Subgroup analysis by cancer site, ethnicity, source of controls and gender was performed.

Results

The T allele of HIF-1α gene C1772T was significantly associated with increased cancer risk in three genetic models: TT+CT vs.CC (dominant model OR=1.23, 95%CI=1.03-1.47), TT vs. CT+CC (recessive model OR=2.51, 95%CI=1.54-4.09), TT vs. CC (homozygote comparison OR=2.02, 95%CI=1.21-3.39).In subgroup analysis, the frequency of the T variant was found to be significantly increased in cervical cancer, pancreatic cancer, head and neck cancer, renal cell carcinoma, Asian and female subgroups.

Conclusions

Our meta-analysis suggests that the substitution of C allele with T at HIF-1α gene C1772T polymorphism is a risk factor of cancer, especially for cervical, head and neck cancer, pancreatic cancer and renal cell carcinoma. It is also a risk factor of cancer in Asian group as well as in female group.

Hypoxia-inducible factor-1α polymorphisms link to coronary artery collateral development and clinical presentation of coronary artery disease

AIMS

This study aimed to investigate the association of Hypoxia-inducible factor-1α (HIF-1α) C1772T and G1790A single nucleotide polymorphisms (SNPs) with: incidence, clinical type, severity of coronary atherosclerosis and coronary collaterals of coronary artery disease (CAD).

METHODS

The clinical data and genomic DNA were gathered in 958 subjects, including 560 controls and 398 patients with CAD. CAD was confirmed with coronary angiography (CAG). The genotypes for two SNPs were determined by high resolution melting after PCR amplification.

RESULTS

Neither the HIF-1α C1772T nor the G1790A genotype was significantly associated with CAD and, no gene-gene or gene-environmental interactions were identified. However, both HIF-1α C1772T and G1790A (P<0.05) alleles were associated with clinical type and formation of coronary collaterals (P<0.05). Patients carrying genotype CT (P=0.019, OR=4.905,91, 95% CI: 1.355-17.761) and GA (P=0.026, OR=3.052, 95% CI: 1.180-7.892) had significantly higher stable angina pectoris (SAP) than unstable angina pectoris (UAP) and acute myocardial infarction (AMI). The presence of HIF-1 genotype CT (P=0.016, OR=13.373, 95% CI: 15.468-32.709) and GA (P=0.001, OR=19.741, 95% CI: 8.125-47.966) predicted lower collateral formation and severity of CAD secondary to the absence of collaterals (r=0.242, P<0.001).

CONCLUSIONS

We conclude that functional polymorphisms in the HIF-1α gene do not modify CAD risk but they are associated with the formation of coronary collaterals and clinical presentation of CAD.

HIF-1α P582S and A588T polymorphisms and digestive system cancer risk-a meta-analysis

Hypoxia-inducible factor-1 (HIF-1) influences cancer progression and metastasis through various mechanisms, and HIF-1α polymorphisms are reportedly associated with many cancers; however, the associations of HIF-1α P582S and A588T polymorphisms with the risk of digestive system cancer remain inconclusive. To understand the role of HIF-1α P582S and A588T genotypes in digestive cancer development, we conducted a comprehensive meta-analysis involving 1,517 cases and 3,740 controls. Overall, the P582S polymorphism was not significantly associated with digestive system cancers in all genotypes. By contrast, the A588T polymorphism was significantly associated with digestive system cancers in the dominant model (TT/AT vs. AA: OR = 3.17, 95% CI: 1.21, 8.25; P heterogeneity < 0.001). In subgroup analysis for cancer types, the two polymorphisms were only associated with increased risk of pancreatic cancer (P582S: SS vs. PP: OR = 2.51, 95% CI: 1.31, 4.81; SS vs.

PP/PS

OR = 8.73, 95% CI: 1.33, 57.1; A588T: TT vs. AA: OR = 9.30, 95% CI: 1.12, 77.6; P heterogeneity = 0.478; TT vs.

AA/AT

OR = 3.14, 95% CI: 1.99, 4.97; P heterogeneity = 0.098; TT/AT vs. AA: OR = 8.65, 95% CI: 1.05, 71.6; P heterogeneity = 0.418). According to the source of ethnicity, the P582S and the A588T polymorphisms are both significantly associated with an increased risk of cancer among Caucasians in the homozygote model (SS vs. PP: OR = 2.41, 95% CI: 1.24, 4.691; P heterogeneity = 0.010; TT vs. AA: OR = 98.6, 95% CI: 4.37, 2,224; P heterogeneity = 0.040) and the recessive model (SS vs.

PP/PS

OR = 9.48, 95% CI: 1.12, 80.3; P heterogeneity < 0.001; TT vs.

AA/AT

OR = 82.7, 95% CI: 3.79, 1,802; P heterogeneity = 0.041). Our findings suggest that the HIF-1α A588T polymorphism is significantly associated with higher cancer risk and the P582S polymorphism is significantly associated with pancreatic cancer risk. Furthermore, the effect of both polymorphisms on digestive system cancer is more pronounced among Caucasians than that among Asians.

HIF-1α 1772 C/T and 1790 G/A polymorphisms are significantly associated with higher cancer risk: an updated meta-analysis from 34 case-control studies

Background

HIF-1 activates various genes in cancer progression and metastasis. HIF-1α 1772 C/T and 1790 G/A polymorphisms are reportedly associated with cancer risk; however, the results are inconclusive.

Methodology/Principal Findings

A meta-analysis of 34 studies that involved 7522 cases and 9847 controls for 1772 C/T and 24 studies that involved 4884 cases and 8154 controls for 1790 G/A was conducted to identify the association of C/T and G/A polymorphisms with cancer risk. Odds ratio (OR) and 95% confidence intervals (95% CI) were used to assess the strength of association.

HIF-1α 1772 C/T and 1790 G/A polymorphisms were associated with higher cancer risk in homozygote comparison (1772C/T: TT vs. CC: OR = 2.45, 95% CI: 1.52, 3.96; P_{heterogeneity} = 0.028; 1790G/A: AA vs. GG: OR=4.74, 95% CI: 1.78, 12.6; P_{heterogeneity} < 0.01), dominant model (1772C/T: TT/CT vs. CC: OR = 1.27, 95% CI: 1.04, 1.55; P_{heterogeneity} < 0.01, 1790G/A: AA/GA vs. GG: OR = 1.65, 95% CI: 1.05, 2.60; P_{heterogeneity} < 0.01), T allele versus C allele (T vs. C: OR = 1.42, 95% CI: 1.18, 1.70; P_{heterogeneity} < 0.01), and A allele versus G allele (A vs. G: OR = 1.83, 95% CI: 1.13, 2.96; P_{heterogeneity} < 0.01). On a subgroup analysis, the 1772 C/T polymorphism was significantly linked to higher risks for breast cancer, lung cancer, prostate cancer, and cervical cancer, whereas the 1790 G/A polymorphism was significantly linked to higher risks for lung cancer and prostate cancer. A significantly increased cancer risk was found in both Asians and Caucasians for 1772C/T polymorphism, whereas a significantly increased cancer risk was found in Caucasians in the heterozygote comparison and recessive model for 1790G/A polymorphism.

Conclusions

HIF-1α 1772 C/T and 1790 G/A polymorphisms are significantly associated with higher cancer risk.

The HIF1A functional genetic polymorphism at locus +1772 associates with progression to metastatic prostate cancer and refractoriness to hormonal castration

The hypoxia inducible factor 1 alpha (HIF1a) is a key regulator of tumour cell response to hypoxia, orchestrating mechanisms known to be involved in cancer aggressiveness and metastatic behaviour. In this study we sought to evaluate the association of a functional genetic polymorphism in HIF1A with overall and metastatic prostate cancer (PCa) risk and with response to androgen deprivation therapy (ADT). The HIF1A +1772 C>T (rs11549465) polymorphism was genotyped, using DNA isolated from peripheral blood, in 1490 male subjects (754 with prostate cancer and 736 controls cancer-free) through Real-Time PCR. A nested group of cancer patients who were eligible for androgen deprivation therapy was followed up. Univariate and multivariate models were used to analyse the response to hormonal treatment and the risk for developing distant metastasis. Age-adjusted odds ratios were calculated to evaluate prostate cancer risk. Our results showed that patients under ADT carrying the HIF1A +1772 T-allele have increased risk for developing distant metastasis (OR, 2.0; 95%CI, 1.1-3.9) and an independent 6-fold increased risk for resistance to ADT after multivariate analysis (OR, 6.0; 95%CI, 2.2-16.8). This polymorphism was not associated with increased risk for being diagnosed with prostate cancer (OR, 0.9; 95%CI, 0.7-1.2). The HIF1A +1772 genetic polymorphism predicts a more aggressive prostate cancer behaviour, supporting the involvement of HIF1a in prostate cancer biological progression and ADT resistance. Molecular profiles using hypoxia markers may help predict clinically relevant prostate cancer and response to ADT.

HIF-1α C1772T polymorphism and gastrointestinal tract cancer risk: a meta-analysis and meta-regression analysis

OBJECTIVE

Recent evidence suggests that genetic variations in the hypoxia inducible factor-1α (HIF-1α) gene may have an impact on an individual's susceptibility to gastrointestinal tract (GIT) cancer; but individually published results are inconclusive. This meta-analysis aims to derive a precise estimation of the association between a common polymorphism (C1772T; rs11549465 C>T) in the HIF-1α gene and susceptibility to GIT cancer.

METHODS

An extensive literature search was conducted for appropriate articles published before May 1st, 2013. This meta-analysis was performed using the STATA 12.0 software. The crude odds ratio with 95% confidence interval was calculated.

RESULTS

Six case-control studies were assessed with a total of 911 GIT cancer patients and 2774 healthy controls. Our meta-analysis indicated that the C variant of HIF-1α C1772T polymorphism appeared to confer an increased risk for GIT cancer. Further subgroup analyses indicated that the C variant of HIF-1α C1772T polymorphism may increase the risk of GIT cancer among Asian populations, but not among Caucasian populations. Univariate and multivariate meta-regression analyses confirmed that differences in ethnicity and cancer type are the major sources of heterogeneity. No publication bias was detected in this meta-analysis.

CONCLUSION

The current meta-analysis suggests that the C variant of HIF-1α C1772T polymorphism may increase the risk of GIT cancer, especially among Asian populations.

The association between HIF-1α polymorphism and cancer risk: a systematic review and meta-analysis

Epidemiological studies have assessed the association between HIF-1α polymorphisms and cancer risk. However, the results remained conflicting rather than conclusive. Therefore, we performed a systematic review to provide a complete picture and conducted a meta-analysis to derive a precise estimation. We searched PubMed, Embase, and China National Knowledge Infrastructure (CNKI) databases until July 2013 to identify eligible studies. Data sets (43) from 39 studies with a total of 10,841 cases and 14,682 controls were included. The most commonly investigated polymorphism was C1772T, followed by G1790A, C111A, and rs2057482. Overall, C1772T and G1790A but not rs2057482 were associated with increased risk for cancer. When stratified by cancer type, C1772T was associated with increased risk for cervical cancer (T/T vs. C/T+C/C: OR = 8.80, 95 % CI = 2.30-33.70), prostate cancer (T vs. C: OR = 1.54, 95 % CI = 1.04-2.30), and other cancers (T vs. C: OR = 1.42, 95 % CI = 1.07-1.89), but not oral, breast, colorectal, endometrial, lung, and bladder cancers or renal cell carcinoma. G1790A was associated with marginal but insignificant risk for prostate cancer (A vs. G: OR = 1.46, 95 % CI = 1.00-2.13, P = 0.056) and with increased risk for oral (A vs. G: OR = 9.66, 95 % CI = 1.31-71.15), lung (A vs. G: OR = 2.27, 95 % CI = 1.74-2.96), and other cancers (A vs. G: OR = 2.06, 95 % CI = 1.26-3.37) and renal cell carcinoma (A/A vs. G/A+G/G: OR = 3.05, 95 % CI = 1.36-6.84), but not breast, colorectal, cervical, or bladder cancer. Furthermore, we detected increased cancer risk in haplotypes TA and CA and in those carrying at least one risk allele, and decreased cancer risk in haplotype TG regarding C1772T and G1790A polymorphisms. Further well-designed studies on various cancer types are warranted to verify our findings.

Hypoxia-inducible factor-1α polymorphisms and risk of cancer metastasis: a meta-analysis

Background

HIF-1α is a major regulator in tumor progression and metastasis which responds to hypoxia. Many studies have demonstrated that hypoxia-inducible factor1-α (HIF-1α) polymorphisms are significantly associated with cancer metastasis, but the results are inconsistent. We conducted a comprehensive meta-analysis to estimate the associations between HIF-1α C1772 T polymorphism and cancer metastasis.

Methods

Comprehensive searches were conducted on PubMed and EMBASE database. Fifteen studies were included in the meta-analysis. We used the OR and 95%CI to assess the associations between HIF-1α C1772T polymorphism and cancer metastasis. Heterogeneity and publication bias were also assessed by Q test, I², and funnel plot.

Results

Totally, fifteen studies including 1239 cases with metastasis-positive (M+) and 2711 cases with metastasis-negative (M−) were performed in this meta-analysis. The results showed that HIF-1a C1772T polymorphism was associated with the increased risk of cancer metastasis (T allele vs. C allele, OR  = 1.36, 95% CI  = 1.12–1.64; TT+ TC vs. CC, OR  = 1.39, 95% CI  = 1.13–1.71; TT vs. TC+ CC, OR  = 1.93, 95% CI  = 0.86–4.36). In the subgroup analyses, the significant associations remained significant among Asians, Caucasians and other cancers in the dominant model. Publication bias was not observed in the analysis.

Conclusions

Our results indicate that the HIF-1αC1772T polymorphism T allele may increase the risk of cancer metastasis, which might be a potential risk factor of cancer progress.

Hypoxia-inducible factor-1α(Pro-582-Ser) polymorphism prevents iron deprivation in healthy blood donors

BACKGROUND

Frequent blood loss induces progressive depletion of iron stores, leading to iron deficiency and, ultimately, to overt iron-deficient anaemia. The erythropoietin-mediated bone marrow response to anaemia is under the control of hypoxia-inducible factors (HIF), the master regulators of oxygen and iron homeostasis. Since the HIF-1α(Pro-582-Ser) variant is associated with elevated trans-activation capacity of hypoxia responsive elements of target genes, we investigated whether the HIF-1α(Pro-582-Ser) polymorphism might influence the response to repeated blood withdrawals.

MATERIALS AND METHODS

Using polymerase chain reaction analysis and DNA sequencing, we retrospectively investigated the presence of HIF-1α(Pro-582-Ser) in a series of 163 blood donors. Haematological findings, serum ferritin levels and frequency of donations were compared according to the mutational status of the HIF-1α gene.

RESULTS

We found that male carriers of the HIF-1α(Pro-582-Ser) polymorphism had higher haemoglobin and ferritin levels than individuals homozygous for the wild-type allele. Moreover, the HIF-1α(Pro-582-Ser) polymorphism protected regular blood donors from developing iron deficiency and anaemia and predicted uninterrupted donation activity.

DISCUSSION

These findings show for the first time that the HIF-1α(Pro-582-Ser) polymorphism significantly affects red blood cell and iron homeostasis after blood loss, conferring to male carriers a resistance to anaemia. Regarding the female gender, large series of individuals should be investigated to establish whether there is an effect of the HIF-1α(Pro-582-Ser) polymorphism in this population. Although these data need to be confirmed in prospective studies, they could have important implications in blood donor selection and donation procedures.

Impact of the hypoxia-inducible factor-1 α (HIF1A) Pro582Ser polymorphism on diabetes nephropathy

OBJECTIVE

Hypoxia plays a major pathogenic role in diabetic nephropathy (DN). We have investigated in this study the effect of hypoxia-inducible factor 1 α subunit (HIF1A) genetic polymorphisms on the development of DN.

RESEARCH DESIGN AND METHODS

In 1,165 American type 1 diabetic patients with and without DN selected from the Genetics of Kidneys in Diabetes (GoKinD) study, the HIF1A genetic polymorphisms were genotyped with TaqMan allelic discrimination. The regulation of HIF-1α in the kidneys of diabetic mice was appreciated by immunohistochemistry, and the effect HIF1A Pro582Ser polymorphism on HIF-1α sensitivity to glucose was evaluated in vitro.

RESULTS

We identified a protective association between HIF1A Pro582Ser polymorphism and DN in male subjects. We also provided mechanistic insights that HIF-1α is repressed in the medulla of diabetic mice despite hypoxia and that Pro582Ser polymorphism confers less sensitivity to the inhibitory effect of glucose during a hypoxic challenge.

CONCLUSIONS

The current study demonstrates for the first time that HIF1A Pro582Ser polymorphism has an effect on DN, possibly by conferring a relative resistance to the repressive effect of glucose on HIF-1α.

Genetic polymorphisms in HIF1A are associated with prostate cancer risk in a Chinese population

The hypoxia-inducible factor-1α (HIF-1α) plays an important role in regulating angiogenesis, which is essential for tumor growth and metastasis. Genetic variations of HIF1A (coding HIF-1α) have been shown to influence an individual's susceptibility to many human tumors; however, evidence on associations between HIF1A single-nucleotide polymorphisms (SNPs) and prostate cancer (PCa) risk is conflicting. We genotyped three potentially functional polymorphisms in HIF1A (rs11549465, rs11549467 and rs2057482) using the TaqMan method and assessed their associations with PCa risk in a case-control study of 662 PCa patients and 716 controls in a Chinese Han population. Compared with rs11549467 GG genotype, the variant genotypes GA+AA had a significantly increased PCa risk (adjusted odds ratio (OR)=1.70; 95% confidence interval (CI)=1.06-2.72), particularly among older patients (OR=2.01; 95%CI=1.05-3.86), smokers (OR=2.06; 95%CI=1.07-3.99), never drinkers (OR=2.16; 95%CI=1.20-3.86) and patients without a family history of cancer (OR=1.71; 95%CI=1.02-2.89). Furthermore, patients with rs11549467 variant genotypes were associated with a higher Gleason score (OR=2.14; 95%CI=1.22-3.75). No altered PCa risk was associated with the rs11549465 and rs2057482 polymorphism. However, the combined variant genotypes of rs2057482 and rs11549467 were associated with increased PCa risk (OR=2.10; 95%CI=1.23-3.57 among subjects carrying three or more risk alleles). These results suggest that HIF1A polymorphisms may impact PCa susceptibility and progression in the Chinese Han population.

Common polymorphisms in angiogenesis

A wide variety of diseases have a significant genetic component, including major causes of morbidity and mortality in the western world. Many of these diseases are also angiogenesis dependent. In humans, common polymorphisms, although more subtle in effect than rare mutations that cause Mendelian disease, are expected to have greater overall effects on human disease. Thus, common polymorphisms in angiogenesis-regulating genes may affect the response to an angiogenic stimulus and thereby affect susceptibility to or progression of such diseases. Candidate gene studies have identified several associations between angiogenesis gene polymorphisms and disease. Similarly, emerging pharmacogenomic evidence indicates that several angiogenesis-regulating polymorphisms may predict response to therapy. In contrast, genome-wide association studies have identified only a few risk alleles in obvious angiogenesis genes. As in other traits, regulatory polymorphisms appear to dominate the landscape of angiogenic responsiveness. Rodent assays, including the mouse corneal micropocket assay, tumor models, and a macular degeneration model have allowed the identification and comparison of loci that directly affect the trait. Complementarity between human and animal approaches will allow increased understanding of the genetic basis for angiogenesis-dependent disease.

HSP90, HSPA8, HIF-1 alpha and HSP70-2 polymorphisms in breast cancer: a case-control study

This case control study aims to investigate the role of HSP90 Gln488His (C > G), HSP70-2 P1/P2, HIF-1 alpha C1772T and HSPA8 intronic 1541-1542delGT polymorphisms as potential risk factors and/or prognostic markers for breast cancer. 113 consecutive incident cases of histologically confirmed ductal breast cancer and 124 healthy cases were recruited. The above mentioned polymorphisms were genotyped; multivariate logistic regression was performed. HSP90 GG (His/His) genotype was associated with elevated breast cancer risk. Similarly, the allele dose-response model pointed to increase in breast cancer risk per G allele. HSP70-2 P1/P2, HSPA8 intronic 1541-1542delGT and HIF-1 alpha polymorphisms were not associated with breast cancer risk, as evidenced by the dose-response allele models. The positive association between HSP90 G allele and breast cancer risk seemed to pertain to both premenopausal and postmenopausal women. With respect to survival analysis, none of the aforementioned polymorphisms was associated with either disease-free survival or overall survival. HSP90α Gln488His polymorphism seems to be a risk factor for breast cancer. On the other hand, our study did not point to excess risk conferred by HSPA8 1541-1542delGT, Hsp70-2 P1/P2 and HIF-1α C1772T.

Polymorphisms in HIF-1alpha affect presence of lymph node metastasis and can influence tumor size in squamous-cell carcinoma of the glottic larynx

BACKGROUND

HIF-1alpha plays a key role in the development and progression of cancer. Its polymorphic variants C1772T and G1790A have been associated with greater susceptibility to cancer and increased tumor progression.

METHODS

We determined the distribution of these polymorphisms among 121 patients with glottic cancer and 154 healthy volunteers by PCR-RFLP. We also analyzed the relationship between the presence of these polymorphisms and various clinicopathologic variables.

RESULTS

Advanced tumors (T3-T4) were associated with the TT variant (p = 0.036), which was present in 75 % of T4 tumors (p = 0.008). Among patients with nodal metastasis (N+), 41.7 and 22 % were carrying the TT and GA variants, respectively, compared with 9.4 and 2 % of the patients with no metastasis (N0), (p = 0.006 and p = 0.032).

CONCLUSIONS

The presence of the TT and GA variants were associated with lymph node metastasis, while the presence of the TT variant can be associated with larger tumor size.

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.

The polymorphisms in the VHL and HIF1A genes are associated with the prognosis but not the development of renal cell carcinoma

BACKGROUND

The von Hippel-Lindau (VHL) tumor suppressor gene and hypoxia-inducible factor-1α (HIF1A) play a pivotal role in renal carcinogenesis. This study was aimed to clarify the influence of VHL and HIF1A polymorphisms on renal cell cancer (RCC) susceptibility and survival.

SUBJECTS AND METHODS

We genotyped four potentially functional single-nucleotide polymorphisms (rs779805 in VHL and rs11549465, rs11549467, and rs2057482 in HIF1A) and assessed their associations with RCC risk, clinicopathologic parameters in a case-control study of 620 patients and 623 controls, and the prognosis of RCC in a cohort of 311 patients.

RESULTS

No significant differences in VHL or HIF1A genotypes were observed between RCC cases and controls. However, individuals with ≥2 variant alleles of the four polymorphisms were associated with less frequent lymph node metastasis and lower clinical stage (P = 0.032 and P = 0.041, respectively). And the number of variant alleles was associated with improved survival in a dose-response manner (P(trend) = 0.013). Furthermore, multivariate Cox regression analysis showed that the number of variant alleles (≥1 versus 0) was an independent prognostic factor for RCC survival (P = 0.036) together with clinical stage and tumor grade.

CONCLUSION

The VHL and HIF1A polymorphisms may not influence RCC susceptibility but may jointly influence RCC progression and survival.

Interactions between nitric oxide and hypoxia-inducible factor signaling pathways in inflammatory disease

Induction and activation of nitric oxide (NO) synthases (NOS) and excessive production of NO are common features of almost all diseases associated with infection and acute or chronic inflammation, although the contribution of NO to the pathophysiology of these diseases is highly multifactorial and often still a matter of controversy. Because of its direct impact on tissue oxygenation and cellular oxygen (O(2)) consumption and re-distribution, the ability of NO to regulate various aspects of hypoxia-induced signaling has received widespread attention. Conditions of tissue hypoxia and the activation of hypoxia-inducible factors (HIF) have been implicated in hypoxia or in cancer biology, but are also being increasingly recognized as important features of acute and chronic inflammation. Thus, the activation of HIF transcription factors has been increasingly implicated in inflammatory diseases, and recent studies have indicated its critical importance in regulating phagocyte function, inflammatory mediator production, and regulation of epithelial integrity and repair processes. Finally, HIF also appears to contribute to important features of tissue fibrosis and epithelial-to-mesenchymal transition, processes that are associated with tissue remodeling in various non-malignant chronic inflammatory disorders. In this review, we briefly summarize the current state of knowledge with respect to the general mechanisms involved in HIF regulation and the impact of NO on HIF activation. Secondly, we will summarize the major recent findings demonstrating a role for HIF signaling in infection, inflammation, and tissue repair and remodeling, and will address the involvement of NO. The growing interest in hypoxia-induced signaling and its relation with NO biology is expected to lead to further insights into the complex roles of NO in acute or chronic inflammatory diseases and may point to the importance of HIF signaling as key feature of NO-mediated events during these disorders.