Quantitative assessment of the association between GSTP1 gene Ile105Val polymorphism and susceptibility to hepatocellular carcinoma

Gene variations related to the hepatocellular carcinoma: Results from a field synopsis and Bayesian revaluation

Hepatocellular carcinoma (HCC) is considered as the second cause of cancer-related deaths worldwide. Genetic variations are associated with HCC risk, an issue that has been the subject of several meta-analyses. However, meta-analyses have an important limitation on the likelihood of false positive data. Henceforth, this study aimed to assess the level of noteworthiness in the meta-analyses by means of a Bayesian approach. A systematic search was performed for meta-analyses with associations between gene polymorphisms and HCC. The calculations for the False-Positive Rate Probability (FPRP) and the Bayesian False Discovery Probability (BFDP) were performed to assess the noteworthiness with a statistical power of 1.2 and 1.5 of Odds Ratio at a prior probability of 10^-3 and 10^-5. The quality of studies was evaluated by the Venice criteria. As additional analyses, the gene-gene and protein-protein networks were designed for these genes and products. As results, we found 33 meta-analytic studies on 45 polymorphisms occurring in 35 genes. A total of 1,280 values for FPRP and BFDP were obtained. Seventy-five for FPRP (5.86%) and 95 for BFDP (14.79%) were noteworthy. In conclusion, the polymorphisms in CCND1, CTLA4, EGF, IL6, IL12A, KIF1B, MDM2, MICA, miR-499, MTHFR, PNPLA3, STAT4, TM6SF2, and XPD genes were considered as noteworthy biomarkers for HCC risk.

Polymorphisms in xenobiotic metabolism-related genes in patients with hepatocellular carcinoma: a case-control study

This study was performed to investigate the relationship between polymorphisms in microsomal epoxide hydrolase (mEH; Tyr113His and His139Arg substitution) and glutathione S-transferase (GST; GSTM1 deletion, GSTT1 deletion, and GSTP1.Ala114Val substitution) and their correlation with clinico-histopathological features in hepatocellular carcinoma (HCC).We evaluated environmental risk factors and genetic alterations in 556 individuals (86 cases and 470 controls). PCR multiplex for GSTM1 and GSTT1, polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) for GSTP1, and real-time PCR for mEH were performed. Statistical analyses were performed using multiple logistic regression tests.Age over 48 years (p < 0.001) and alcohol consumption (p = 0.021) were the predictors of increased risk of developing HCC. GSTP1.Ala114Val for all regression models (p < 0.05), except the recessive model, and the GSTT1 null genotype (odds ratio [OR] = 0.43, 95% confidence interval [CI] = 0.21-0.87, p = 0.019) were predictors of an increased risk of developing HCC. Polymorphic GSTT1, GSTM1, GSTP1.Ala114Val, and mEH.His139Arg and wild-type mEH.Tyr113His (OR = 5.04; 95% CI = 1.59-16.04; p = 0.006) were associated with HCC.Age over 48 years, alcohol consumption, and the presence of polymorphic variants of GSTP1 and GSTT1 were associated with the risk of developing HCC.

Relation between GSTP1 polymorphism and oxidative stress in patients with hepatocellular carcinoma

BACKGROUND

Glutathione can reduce the oxidative stress by converting the unstable to stable molecules and its status in hepatocellular carcinoma (HCC) is correlated with tumor growth and metastasis. Glutathione S-transferase Pi (GSTP1) is reported to detoxify the xenobiotic substrates by catalyzing their conjugation to reduced glutathione (GSH) and its over-expression was demonstrated in the early stages of HCC, while loss of GSTP1 has been suggested to increase the risk of deoxyribonucleic acid (DNA) damage and mutation. The aim of this study is to assess the relationship of GSTP1 polymorphism Ile105Val (rs1695 A > G) with HCC risk, and to investigate the oxidative stress status of HCC patients by measuring the antioxidant glutathione (GSH) levels. This study was conducted on 99 newly diagnosed HCC patients and 80 apparently healthy individuals as a normal control group. All participants were subjected to the measurement of plasma GSH levels according to Ellman's method, and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for the detection of GSTP1 polymorphismIle105Val (rs1695 A > G).

RESULTS

The occurrence of either the mutant homozygous or the mutant heterozygous genotype of GSTP1 was significantly higher in HCC patients, while the occurrence of the wild genotype was significantly higher among the normal control subjects. Mutant GSTP1 genotype, older age, male gender, and high serum alanine aminotransferase (ALT) were associated with increased risk of development of HCC. The best sensitivity, specificity, PPV (positive predictive value), NPV (negative predictive value), and overall diagnostic performance for plasma GSH at a cutoff level of 2003.5 μM/mg were 57.6%, 52.5%, 60%, and 40%. The area under the curve for GSH was 0.562.

CONCLUSION

Mutant GSTP1 genotype was an independent prognostic factor for increased HCC risk which can be used in a risk assessment model for HCC. Plasma GSH presents insufficient sensitivity and specificity for HCC.

Autophagy impacts on oxaliplatin-induced hepatocarcinoma apoptosis via the IL-17/IL-17R-JAK2/STAT3 signaling pathway

The interleukin (IL)-17/IL-17 receptor (IL-17R) complex has been shown to be important for the regulation of inflammation; however, its role in the regulation of tumor processes has recently emerged as a research focus. The present study demonstrated that oxaliplatin was able to increase the levels of IL-17/IL-17R in hepatocellular carcinoma (HCC) patients and cells lines, and that it had important roles in reducing the susceptibility of the cells to oxaliplatin-induced apoptosis. Furthermore, the expression of autophagy-related proteins was induced by IL-17/IL-17R and autophagy was shown to induce resistance to oxaliplatin in HCC. In addition, the janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway was shown to be an important pathway in the induction of autophagy in response to oxaliplatin. Autopjhagy was inhibited by 3-methyladenine and JAK2/STAT3 signaling was blocked by AG490, which induced apoptosis in SMMC7721 cells treated with oxaliplatin. The results of the present study may help to elucidate the mechanism underlying the role of IL-17/IL-17R-induced autophagy in the chemoresistance of HCC, as well as help to establish and develop measures to overcome chemoresistance in HCC.

Quantitative Proteomics Analysis of the Hepatitis C Virus Replicon High-Permissive and Low-Permissive Cell Lines

Chronic hepatitis C virus (HCV) infection is one of the leading causes of severe hepatitis. The molecular mechanisms underlying HCV replication and pathogenesis remain unclear. The development of the subgenome replicon model system significantly enhanced study of HCV. However, the permissiveness of the HCV subgenome replicon greatly differs among different hepatoma cell lines. Proteomic analysis of different permissive cell lines might provide new clues in understanding HCV replication. In this study, to detect potential candidates that might account for the differences in HCV replication. Label-free and iTRAQ labeling were used to analyze the differentially expressed protein profiles between Huh7.5.1 wt and HepG2 cells. A total of 4919 proteins were quantified in which 114 proteins were commonly identified as differentially expressed by both quantitative methods. A total of 37 differential proteins were validated by qRT-PCR. The differential expression of Glutathione S-transferase P (GSTP1), Ubiquitin carboxyl-terminal hydrolase isozyme L1 (UCHL1), carboxylesterase 1 (CES1), vimentin, Proteasome activator complex subunit1 (PSME1), and Cathepsin B (CTSB) were verified by western blot. And over-expression of CTSB or knock-down of vimentin induced significant changes to HCV RNA levels. Additionally, we demonstrated that CTSB was able to inhibit HCV replication and viral protein translation. These results highlight the potential role of CTSB and vimentin in virus replication.

Hepatocellular carcinoma epidemiology

Primary liver cancer (namely hepatocellular carcinoma, HCC) is worldwide the fifth most common cancer in men and the seventh one in women, and it represents the third most frequent cause of cancer death. HCC rates are particularly high in eastern/south-eastern Asia and in Africa, intermediate in Southern Europe, and low in most high-income countries. Persistent infections by HBV or HCV are the main recognized risk factors for HCC. Aflatoxin exposure is also an important risk factor for HCC development in Africa and eastern Asia. In high-income countries heavy alcohol drinking, tobacco smoking, overweight, diabetes, familial/genetic factors, and selected dietary aspects, have a relevant role. Updated geographic patterns and time trends in mortality from HCC in Europe, USA, Japan, and Australia are provided in the present review, together with an overview of relevant etiologic factors for HCC and main measures for the prevention of this neoplasm.

Effects of AFP-activated PI3K/Akt signaling pathway on cell proliferation of liver cancer

This study aims to investigate effects of alpha-fetoprotein (AFP)-activated phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway on hepatocellular carcinoma cell proliferation. Active cirrhosis patients after hepatitis B infection (n = 20) and viral hepatitis patients with hepatocellular carcinoma (HCC) (n = 20) were selected as the subjects of the present study. Another 20 healthy subjects were selected as the control group. The serum AFP expression and liver tissue PI3K and Akt gene mRNA expression were detected. The hepatoma cell model HepG2 which had a stable expression of AFP gene was used. Real-time quantitative PCR and Western blot and other methods were used to analyze the intracellular PI3K and Akt protein levels. Compared with control group and cirrhosis group, the serum AFP levels in HCC group significantly increased, and the tissue PI3K and Akt mRNA expression also significantly increased. HepG2 cells were intervened using AFP, in which the PIK and Akt protein expression significantly increased. After intervention by use of AFP monoclonal antibodies or LY294002 inhibitor, the PIK and Akt protein expression in HepG2 cell was significantly decreased (P < 0.05). AFP can promote the proliferation of hepatoma cells via activation of PI3K/Akt signaling pathway.

GSTP1 Ile105Val polymorphism and prostate cancer risk: evidence from a meta-analysis

BACKGROUND

Glutathione S-transferase P1 (GSTP1) is thought to be involved in the detoxification of reactive carcinogen metabolites. Numerous epidemiological studies have evaluated the association of GSTP1 Ile105Val polymorphism with the risk of prostate cancer. However, the results remain inconclusive. To derive a more precise estimation, a meta-analysis was performed.

METHODOLOGY/PRINCIPAL FINDINGS

A comprehensive search was conducted to identify the eligible studies. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the relationship. The overall association was not significant (Val/Val vs. Ile/Ile OR = 1.06, 95% CI = 0.90-1.25, P = 0.50; Val/Val vs. Val/Ile+Ile/Ile: OR = 1.07, 95% CI = 0.91-1.25, P = 0.44). In subgroup analyses by ethnicity and prostate cancer grade, the similar results were observed. However, in stratified analysis by clinical stage, we found a significant association with low-stage prostate cancer (Val/Val vs. Ile/Ile: OR = 2.70, 95% CI = 1.73-4.22, P<0.001; Val/Val vs. Val/Ile+Ile/Ile: OR = 2.14, 95% CI = 1.38-3.33, P = 0.001). Moreover, there was no statistically significant evidence of multiplicative interactions neither between the GSTP1 Ile105Val polymorphism and GSTM1, nor between smoking status and GSTP1 on prostate cancer risk.

CONCLUSIONS

This meta-analysis showed that GSTP1 Ile105Val polymorphism might not be significantly associated with overall prostate cancer risk. Further stratified analyses showed a significant association with low-stage prostate cancer.