Hypoxic upregulation of glucose transporters in BeWo choriocarcinoma cells is mediated by hypoxia-inducible factor-1

Placental hypoxia has been implicated in pregnancy pathologies, including fetal growth restriction and preeclampsia; however, the mechanism by which the trophoblast cell responds to hypoxia has not been adequately explored. Glucose transport, a process crucial to fetoplacental growth, is upregulated by hypoxia in a number of cell types. We investigated the effects of hypoxia on the regulation of trophoblast glucose transporter (GLUT) expression and activity in BeWo choriocarcinoma cells, a trophoblast cell model, and human placental villous tissue explants. GLUT1 expression in BeWo cells was upregulated by the hypoxia-inducing chemical agents desferroxamine and cobalt chloride. Reductions in oxygen tension resulted in dose-dependent increases in GLUT1 and GLUT3 expression. Exposure of cells to hypoxic conditions also resulted in an increase in transepithelial glucose transport. A role for hypoxia-inducible factor (HIF)-1 was suggested by the increase in HIF-1 as a result of hypoxia and by the increase in GLUT1 expression following treatment of BeWo with MG-132, a proteasomal inhibitor that increases HIF-1 levels. The function of HIF-1 was confirmed in experiments where the hypoxic upregulation of GLUT1 and GLUT3 was inhibited by antisense HIF-1. In contrast to BeWo cells, hypoxia produced minimal increases in GLUT1 expression in explants; however, treatment with MG-132 did upregulate syncytial basal membrane GLUT1. Our results show that GLUTs are upregulated by hypoxia via a HIF-1-mediated pathway in trophoblast cells and suggest that the GLUT response to hypoxia in vivo will be determined not only by low oxygen tension but also by other factors that modulate HIF-1 levels. glucose transporter 1; glucose transporter 3; glucose transport     

IFN-γ+874 A/T polymorphism and cancer risk: an updated analysis based on 32 case-control studies

IFN-γ is a T-helper 1 cytokine and plays important roles in modulating almost all the immune responses, such as hematopoiesis, T-cell differentiation, antiproliferative, antiviral, and antitumor activities. A single nucleotide polymorphism (+874A/T) which is located in the first intron of the human IFN-γ gene can putatively influence the secretion of IFN-γ. Results from previous studies on the association of +874A/T polymorphism with different cancer types remained contradictory. In order to derive a more precise estimation of the relationship, a meta-analysis was performed by searching PubMed, Embase, CNKI, and Chinese Biomedicine Database. Thirty two studies including 4524 cases and 5684 controls were collected for IFN-γ + 874 A/T polymorphism. Summary odds ratios (OR) and corresponding 95% confidence intervals (CIs) for IFN-γ polymorphism and cancer were estimated using fixed- and random-effects models when appropriate. Overall, no evidence indicated that individuals carrying TT or AT genotypes had significantly increased cancer risk when compared with AA genotype carriers. However, stratified analysis by cancer types indicated a significantly increased risk of breast cancer (TT vs AA: OR = 1.58, 95% CI = 1.10–2.27, P_{heterogeneity} = 0.26; TT vs AT/AA: OR = 1.53, 95%CI = 1.14–2.06, P_{heterogeneity} = 0.19). Moreover, significantly elevated risks were observed in African and European populations when population is concerned. Interestingly, when stratified separately by population-based studies and hospital-based studies, significantly elevated risk was found among population-based studies. This meta-analysis suggests that the IFN-γ + 874 T allele is a low-penetrant risk factor for cancer development.     

Association between α1-antichymotrypsin signal peptide −15A/T polymorphism and the risk of Alzheimer’s disease: a meta-analysis

No consensus has been recently reached at the relationship between the α1-antichymotrypsin (ACT) signal peptide −15A/T polymorphism and Alzheimer’s disease (AD) risk. Thus, our study aimed to better assess this association by performing a meta-analysis, including 4,212 cases and 4,039 controls from 29 studies. Odds ratios (ORs) with the 95% confidence interval (CI) were used to assess the strength of relationship between ACT −15A/T polymorphism and AD risk. Overall, a borderline statistically significant association was detected under recessive model comparison in all subjects (AA vs. AT+TT: OR 1.12, 95% CI 1.01–1.25, P = 0.04). But in subgroup analysis by ethnicity, no significant association was found in Caucasians, Asians, or Africans. Moreover, after exclusion of one study which affect the heterogeneity, the ACT A allele and AA genotype were statistically associated with late-onset AD (LOAD) risk (AA vs. TT: OR 1.25, 95% CI 1.06–1.48, P = 0.007, A vs. T: OR 1.12, 95% CI 1.03–1.21, P = 0.008), especially in Caucasians. In conclusion, our study suggests that the common α1-antichymotrypsin signal peptide −15A/T polymorphism may not be a major risk factor for AD. However, the polymorphism is capable of increasing LOAD risk.     

Hyperoxia reverses glucotoxicity-induced inhibition of insulin secretion in rat INS-1 β cells

Chronic hyperglycemia has deleterious effects on pancreatic β-cell function, a process known as glucotoxicity. This study examined whether chronic high glucose (CHG) induces cellular hypoxia in rat INS-1 β cells, and whether hyperoxia (35% O₂) can reverse glucotoxicity-induced inhibition of insulin secretion. CHG (33.3?mm, 96?h) reduced insulin secretion, and down-regulated insulin and pancreatic duodenal homeobox factor 1 gene expression. CHG also increased intracellular pimonidazole-protein adducts, a marker for hypoxia. CHG also enhanced hypoxia-inducible factor 1α (HIF-1α) protein expression and its DNA-binding activity, which was accompanied by a decrease in mRNA expression of glucose transporter 2 (GLUT2), glucokinase and uncoupling protein-2 and an increase in mRNA expression of GLUT1 and pyruvate dehydrogenase kinase 1. Hyperoxia restored the decrease in insulin secretion and the gene expression except for GLUT2, and suppressed intracellular hypoxia and HIF-1α activation. These results suggest that glucotoxicity may cause β-cell hypoxia. Hyperoxia might prevent glucotoxicity-induced β-cell dysfunction and improve insulin secretion.     

Myocardial hypoxia-inducible HIF-1alpha, VEGF, and GLUT1 gene expression is associated with microvascular and ICAM-1 heterogeneity during endotoxemia

The systemic inflammatory response to infection is the leading cause of mortality in North American intensive-care units. Although much is known about inflammatory mediators, the relationships between microregional inflammation, microvascular heterogeneity, hypoxia, hypoxia-inducible gene expression, and myocardial dysfunction are unknown. Male Sprague-Dawley rats were injected intraperitoneally with LPS to test the hypothesis that sepsis-induced local inflammation and increased microvascular heterogeneity are spatially and temporally associated with hypoxia, hypoxia-inducible gene expression, and decreased left-ventricular contractility. Using a combination of three-dimensional microvascular imaging, tissue Po(2), and pressure-volume conductance measurements, we found that 5 h after LPS, minimum oxygen-diffusion distances increased (P < 0.05), whereas tissue oxygenation and contractility both decreased (P < 0.05) in the left ventricle. Real-time RT-PCR analysis revealed that the hypoxia-inducible genes hypoxia-inducible factor (HIF)-1alpha, VEGF, and glucose transporter (GLUT) 1 were all upregulated (P < 0.05) in the left ventricle. Tissue regions expressing ICAM-1, obtained by using laser-capture microdissection, had increased HIF-1alpha and GLUT1 (P < 0.05) gene expression. VEGF gene expression was more diffuse. In LPS rats, GLUT1 gene expression correlated (P < 0.05) with left-ventricular contractility. In 5-h hypoxic cardiomyocytes, we found strong transient HIF-1alpha, weak VEGF, and greater prolonged GLUT1 gene expression. By comparison, the HIF-1alpha-GLUT1 gene-induction pattern was reversed in the left ventricle of LPS rats. Together, these results show that LPS induces hypoxia in the left ventricle associated with increased microvascular heterogeneity and decreased contractility. HIF-1alpha and GLUT1 gene induction are related to a heterogeneous ICAM-1 expression and may be cardioprotective during the onset of septic injury.     

The expression of HIF-1α in primary hepatocellular carcinoma and its correlation with radiotherapy response and clinical outcome

The purpose of this study was to evaluate the relationship between hypoxia-inducible factor-1α (HIF-1α) protein expression in hepatocellular carcinoma (HCC), and responses of abdominal metastatic lymph nodes (LNs) from HCC patients treated with external beam radiotherapy (EBRT). HIF-1α immunohistochemical staining was performed on tissue microarrays (TMAs) of primary HCC specimens from 69 HCC patients with abdominal LN metastases. All patients received abdominal metastatic LN EBRT at the Department of Radiation Oncology at Zhongshan Hospital. A receiver-operating characteristic (ROC)-based approach and logistical regression analysis were used to determine the predictive value of HIF-1α expression in primary tumors with HCC metastatic LN EBRT response. Kaplan–Meier curves and log-rank tests were used to analyze patient survival. Cox proportional hazards regression model was used to analyze independent prognostic factors. HIF-1α expression was correlated with blood hemoglobin (Hb: r = −0.280, P = 0.020), response of abdominal metastatic LNs to EBRT (r = 0.286, P = 0.017), locoregional recurrence (r = 0.278, P = 0.021), and cancer-specific deaths (r = 0.298, P = 0.013). HIF-1α expression was predictive of EBRT response of metastatic LNs [area under the curve (AUC): 0.646; 95% confidence interval (CI): 0.499–0.793; P = 0.047], locoregional recurrence (AUC: 0.657; 95% CI: 0.509–0.805; P = 0.049) and cancer-specific deaths (AUC: 0.671; 95% CI: 0.531–0.812; P = 0.035). Patients with tumors exhibiting high HIF-1α expression had significantly poorer overall survival (OS) than those with low tumor expression of HIF-1α (P = 0.016). Multivariate analysis showed that Hb (P = 0.035), vascular invasion (P = 0.026), Child-Pugh score (P < 0.001), intrahepatic tumor control (P < 0.001), and HIF-1α (P = 0.020) were independent prognosis factors for OS of HCC patients after receiving abdominal metastatic LN EBRT. HIF-1α expression in primary HCCs was associated with EBRT response of abdominal metastatic LNs and poor prognosis.     

Potential impact of ADAM-10 genetic variants with the clinical features of oral squamous cell carcinoma

A disintegrin and metalloproteinase domain-containing protein 10 (ADAM-10) involves in the tumour progression, but the impacts of single-nucleotide polymorphism (SNP) of ADAM-10 on oral squamous cell carcinoma (OSCC) remain unclear. The aim of this study was to investigate the influence of SNP of ADAM-10 on the clinical features of OSCC in male Taiwanese. Five loci of ADAM-10 SNPs including rs653765 (C/T), rs2305421 (A/G), rs514049 (A/C), rs383902 (T/C) and rs2054096 (A/T) were genotyped by TaqMan allelic discrimination in 1138 OSCC patients and 1199 non-OSCC individuals. The ADAM-10 SNP rs2305421 GG (AOR: 1.399, 95% CI: 1.045–1.874, p = 0.024) and G allele (AOR: 1.170, 95% CI: 1.012–1.351, p = 0.034) illustrated a significantly higher genotypic frequencies in the OSCC group compared to the distribution of the ADAM-10 SNP rs2305421 AA wild type. In the subgroup analysis, the ADAM-10 SNP rs383902 TC+CC was significantly correlated to tumour size larger than T2 in betel quid chewer (AOR: 1.375, 95% CI: 1.010–1.872, p = 0.043), while the ADAM-10 SNP rs653765 CT+TT was significantly associated with tumour size larger than T2 in cigarette smoker (AOR: 1.346, 95% CI: 1.023–1.772, p = 0.034). The results from The Cancer Genome Atlas revealed highest ADAM-10 mRNA level in T2 stage of current smokers with head and neck squamous cell carcinoma (HNSCC). In conclusions, the ADAM-10 SNP rs2305421 G allele is associated with the presence of OSCC, and the ADAM-10 SNP rs383902 TC+CC and ADAM-10 SNP rs653765 CT+TT correlates to large tumour size in specific conditions.     

Additive effect of alpha-tocopherol and ascorbic acid in combating ethanol-induced hepatic fibrosis

Abstract

Objective

To investigate the efficacy of combined administration of alpha-tocopherol (AT) and ascorbic acid (AA) in reducing ethanol-induced hepatotoxicity.

Methods

Rats were maintained for 90 days and grouped as follows: I – control rats, II – ethanol, III – alpha-tocopherol, IV – ethanol + alpha-tocopherol, V – AA, VI – ethanol + ascorbic acid, VII – alpha-tocopherol + ascorbic acid, VIII – ethanol + alpha-tocopherol + ascorbic acid. At the end of the experimental period, markers of hepatic function, oxidative stress, and the expression of markers of inflammation and fibrosis were assayed.

Results

The markers of hepatic function, lipid peroxidation products, protein carbonyls, and the expression of nuclear factor kappa B, tumor necrosis factor alpha, transforming growth factor beta 1, cytochrome P4502E1, and collagen Type I were elevated after ethanol administration. All these parameters were reduced in the ethanol group administered AT and AA in combination. The activities of antioxidant enzymes which were reduced by ethanol administration were enhanced on combined administration of AT and AA. The reduction in hepatic fibrosis was almost 20% more in AT and AA co-administered group compared with AT and AA alone treated groups.

Discussion

Combined administration of fat soluble AT and water soluble AA was beneficial against ethanol-induced hepatotoxicity. This may be due to their different subcellular localizations.     

Genotype-specific IL8RA gene expression in bovine neutrophils in response to Escherichia coli lipopolysaccharide challenge

Associations between the AC150887.4:c.-1768T>A SNP (rs41255711), which is located in the 5' upstream region of the IL8RA gene (also known as CXCR1), and the estimated breeding values for somatic cell score in the first (P = 0.019) and second (P = 0.035) lactations were previously reported in a population of Canadian Holstein bulls. In the present study, we evaluated the impact of this SNP on the expression of IL8RA by qRT-PCR. Neutrophils were isolated from whole blood samples from a group of cows with genotypes c.-1768AA (n = 4), c.-1768AT (n = 5) and c.-1768TT (n = 5) after the cows had been challenged in vitro with lipopolysaccharide (LPS). This study demonstrated that LPS-induced expression of IL8RA in cows with the c.-1768AA genotype was significantly greater when compared with the c.-1768AT and c.-1768TT genotypes (P < 0.05) before as well as after in vitro LPS challenge.     

Correlation of -475 IL-2 Promoter Gene Polymorphisms and the Levels of Serum IL-2 on the Risk of Multiple Sclerosis

Background:The aim of present study is to asset the IL-2 promoter gene (SNP -475) as a candidate gene for multiple sclerosis (MS) susceptibility.Methods:This study included 70 patients with relapsing – remitting multiple sclerosis (RRMS) and 50 healthy controls. Following the extraction of genomic DNA from peripheral blood, frequency of genotypes and alleles of SNP -475 was calculated using Restriction fragment length polymorphism-polymer chain reaction (RFLP-PCR) and then the results were analyzed statistically.Results:The results revealed the unusual ratio for the heterozygous (AT) was 1.6972 indicating that heterozygous patients were at higher risk of multiple sclerosis than wild homozygous (AA), and homomutant (TT). The results show protective role for - 475 IL-2 promoter among individuals with multiple sclerosis, (O.R: 0.4872; C.I. 95%: 0.1617- 1.4680) and (O.R: 0.9275; C.I. 95%: 0.2476 - 3.4745) for both AA and TT genotypes, respectively.Conclusion:Our results showed that in this population of Iraqi patients, the AT genotype / A allele of -475 IL-2 promoter gene SNP may include attributed factors for MS predisposition.Key Words: IL-2, Multiple sclerosis, PCR-RFLP SNP     

Association of PD-L1 and HIF-1α Coexpression with Poor Prognosis in Hepatocellular Carcinoma

OBJECTIVE: To investigate the correlation between the expression of PD-L1 and HIF-1α in hepatocellular carcinoma (HCC) tissue and further analyze the association with clinical parameters and the prognostic value of coexpression in HCC patients. METHODS: We assessed the expression of PD-L1 and HIF-1α by immunohistochemistry in tumor tissue from 90 HCC patients who underwent curative hepatectomy. The results were validated in an independent cohort of additional 90 HCC patients. RESULTS: PD-L1 and HIF-1α exhibited in tumor tissue high expression rates of 41.11% (37/90) and 43.33% (43/90), respectively, and their expressions were positively correlated (r = 0.563, P < .01). High expression of PD-L1 was significantly associated with low albumin levels (P < .05); high expression of HIF-1α was significantly correlated with high alpha-fetoprotein (AFP) levels and low albumin levels (P < .05); high expression of both PD-L1 and HIF-1α was also significantly associated with high AFP levels and low albumin levels (P < .05). High expression of PD-L1, HIF-1α, as well as both PD-L1 and HIF-1 α was respectively significantly associated with worse overall survival (OS) and disease-free survival (DFS) (P < .05). Patients with co-overexpression of PD-L1 and HIF-1α had the worst prognosis compared with other groups. Additionally, multivariate Cox regression models suggested that high expression of PD-L1, HIF-1α, as well as both PD-L1 and HIF-1α was an independent prognostic factor for OS and DFS (P < .05). Furthermore, the positive correlation and prognostic values of PD-L1 and HIF-1α were validated in an independent data set. CONCLUSION: We demonstrated that HCC patients with co-overexpression of PD-L1 and HIF-1α in tumor tissue had a significantly higher risk of recurrence or metastasis and death compared with others. Therefore, more frequent follow-up is needed for patients with co-overexpression of PD-L1 and HIF-1α. At the same time, a combinational therapy with HIF-1α inhibitors in conjunction with PD-L1 blockade may be beneficial for HCC patients with co-overexpression in the future.     

MDM2 promoter polymorphism is associated with increased susceptibility to hepatocellular carcinoma in Turkish population

Background: The mouse double minute 2 (MDM2) gene represents one of the central nodes in the p53 pathway. A naturally occurring T/G single nucleotide polymorphism (SNP) in the intronic promoter of MDM2, SNP309 (rs2279744), was shown to influence MDM2 expression and p53 activity. SNP in the promoter region of MDM2 gene has recently been shown to be associated with accelerated tumor formation in both hereditary and sporadic cancers in humans. In this study, we aim to evaluate the association of SNP309 with the risk of hepatocellular carcinoma (HCC) development among Turkish population. Methods: MDM2 SNP309 polymorphism was investigated in 110 confirmed subjects with HCC and 110 cancer-free control subjects matched on age, gender, smoking and alcohol consumption by using a polymerase chain reaction-restriction fragment length polymorphism assay. Results: The allele frequencies of case subjects (T, 0.48; G, 0.52) were significantly different from those of control subjects (T, 0.65; G, 0.35) (p = 0.003). The proportion of GG genotype of the SNP309 in patients with HCC (26%) was significantly higher than that in patients without HCC (14%). We observed that compared with the TT genotype, the genotypes containing G allele [TG (OR, 2.19; 95% CI, 1.18–4.07; p = 0.013) or GG (OR, 3.63; 95% CI, 1.65–8.00; p = 0.001)] were associated with significant increased susceptibility to HCC. Conclusion: Our findings suggest that the MDM2 promoter SNP309 G allele is associated with presence of HCC in Turkish population.     

Cutting edge: hypoxia-inducible factor 1alpha and its activation-inducible short isoform I.1 negatively regulate functions of CD4+ and CD8+ T lymphocytes

To evaluate the role of hypoxia-inducible factor 1alpha (HIF-1alpha) and its TCR activation-inducible short isoform I.1 in T cell functions, we genetically engineered unique mice with: 1) knockout of I.1 isoform of HIF-1alpha; 2) T cell-targeted HIF-1alpha knockdown; and 3) chimeric mice with HIF-1alpha gene deletion in T and B lymphocytes. In all three types of mice, the HIF-1alpha-deficient T lymphocytes, which were TCR-activated in vitro, produced more proinflammatory cytokines compared with HIF-1alpha-expressing control T cells. Surprisingly, deletion of the I.1 isoform, which represents < 30% of total HIF-1alpha mRNA in activated T cells, was sufficient to markedly enhance TCR-triggered cytokine secretion. These data suggest that HIF-1alpha not only plays a critical role in oxygen homeostasis but also may serve as a negative regulator of T cells.     

Frequency distribution of XbaIG > T and HaeIIIT > C <Emphasis Type="Italic">GLUT1</Emphasis> polymorphisms among different Brazilian ethnic groups

GLUT is the major glucose transporter in mammalian cells. Single nucleotide polymorphisms (SNP) at GLUT1 promoter and regulatory regions have been associated to the risk of developing nephropathy in different type 1 and type 2 diabetic populations. It has been demonstrated that differences in allelic and genotypic frequencies of GLUT1 gene (SLC2A1) polymorphisms occur among different populations. Therefore, ethnic differences in distribution of GLUT1 gene polymorphisms may be an important factor in determining gene-disease association. In this study, we investigated the XbaIG > T and HaeIIIT > C polymorphisms in six different Brazilian populations: 102 individuals from Salvador population (Northern Brazil), 56 European descendants from Joinville (South Brazil), 85 Indians from Tiryió tribe (North Brazil) and 127 samples from Southern Brazil: 44 from European descendants, 42 from African descendants and 41 from Japanese descendants. Genotype frequencies from both sites did not differ significantly from those expected under the Hardy–Weinberg equilibrium. We verified that the allele frequencies of both polymorphisms were heterogeneous in these six Brazilian ethnic groups.