The -670A > G polymorphism in the promoter region of the FAS gene is associated with necrosis in periportal areas in patients with chronic hepatitis C

Fas/Fas Ligand pathways gene polymorphisms in pediatric renal allograft rejection

BACKGROUND

An essential milestone in pediatric transplantation is to find noninvasive biomarkers to monitor acute rejection (AR). In this retrospective (Case-control) study, we examined the role of Fas -670A/G and Fas Ligand (FasL) -843C/T gene polymorphisms in allograft nephropathy in pediatric renal transplant recipients.

METHODS

In 47 pediatric kidney transplant recipients and 20 healthy controls, Fas -670A/G and FasL -843C/T gene polymorphisms as well as serum soluble Fas Ligand level (sFasL) were measured.

RESULTS

Serum sFasL levels were significantly higher in transplant recipients children than that in controls (548.25±298.64pg/ml vs 143.17±44.55pg/ml, p=0.0001). There was no significant difference between patients with AR and those without AR in regards to serum sFasL levels (567.70±279.87pg/ml vs 507.85±342.80pg/ml, p=0.56). Fas -670A/G genotypes or alleles were not significantly different between controls and transplant recipients and among transplant recipients with and without AR. (P>0.05 for all). FasL -843C/T genotypes were not different between transplant recipients and controls and among transplant recipients with and without AR (P>0.05 for all). However, Frequency of C allele in transplant patients was significantly higher than that in the control group (44.68% vs 25%, P=0.03). FasL -843C/T alleles were significantly different between patients with and without AR (P=0.03). The percentages of C allele were higher in children with AR (58.82% vs 36.67%). We found that serum FasL and serum creatinine were variables that were independently associated with AR.

CONCLUSION

This study suggests that FasL gene polymorphisms in peripheral blood might be accurate in detecting cellular AR.

FAS and FAS-Ligand Promoter Polymorphisms in Hepatitis B Virus Infection

BACKGROUND

The FAS and FAS-Ligand (FASL) system is an important apoptosis pathway in the liver. The FAS-mediated pathway functions by binding the FASL on the activated cytotoxic T lymphocytes and Natural Killer (NK) cells to the FAS receptor on infected hepatocytes. FAS and FASL polymorphisms, which are related to apoptosis, might influence the outcome of Hepatitis B Virus (HBV) infection.

OBJECTIVES

Thus, the present study aimed to determine if FAS and FASL promoter polymorphisms are associated with the clinical outcome of HBV infection.

PATIENTS AND METHODS

DNA samples were obtained from the infected individuals including chronic carrier (n = 50), chronic hepatitis (n = 50), cirrhosis (n = 25), naturally recovered (n = 26) and compared with those of their matched healthy controls (n = 100). Genotyping for polymorphisms of FAS-670 A/G and -1377 G/A, and FASL -844 C/T was performed using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) assays.

RESULTS

Multiple analyses for genetic association of FAS and FASL polymorphisms were not statistically different between HBV patients (n = 125) and healthy controls (n = 100). However, genotype and allele frequencies of FASL-844 C/T were significantly different between recovered individuals and patients with cirrhosis (P = 0.02 and P=0.01, respectively). Whereas, FAS-670A/G and -1377G/A polymorphisms were similarly distributed in these two groups (P = 0.8 and P = 0.47, respectively).

CONCLUSIONS

The current study results showed that bearing -844T allele in FASL promoter region has a protective effect on cirrhosis and is involved in recovery from infection. In conclusion, it is proposed that HBV infection outcome might be influenced by FASL-844C/T polymorphism through alteration in apoptosis of hepatocytes.

P53 rs1042522 and CD95 rs1800682 genetic variations in HCV-4a response to antiviral therapy

Current estimates indicate that the hepatitis C (HCV) is the leading cause of mortality around the world, with infection rates steadily increasing in Egypt. The dual therapy for this silent epidemic with pegylated-interferon-α2b/ribavirin has markedly improved the success rates in genotype-4 patients. It was reported that apoptosis plays a vital mechanistic role in limiting viral replication. P53, a key regulator of apoptosis, induces CD95 gene expression and subsequently initiates apoptotic cascade to be activated. The current study examined the impact of P53 rs1042522 and CD95 rs1800682 polymorphisms on the treatment response. Three groups of 240 volunteers were enrolled in this study; 86 in sustained virological responders group, 74 in non-responders group, and 80 in control group. All patients had HCV genotype-4a and were interferon treatment naïve. Quantizations of HCV-RNA by qRT-PCR and histological scores were performed for all patients. In addition, genotyping of HCV-RNA, P53 rs1042522 Arg/Pro and CD95 rs1800682 A/G polymorphisms were investigated in all subjects. It was resulted that P53 Pro/Pro homozygous genotype has high significant increase, while CD95 A/A homozygous genotype has high significant decrease when comparing non-responders with responders. Finally, it was concluded that Pro variant of P53 rs1042522 may be used as a genetic predictor for non-responsiveness, while A/A variant of CD95 rs1800682 may be used as a sensitive biomarker for responsiveness to antiviral therapy of HCV genotype-4a infection. In addition, low prolactin, high total testosterone, and high GH levels may provide promising biomarkers for early prediction of the response when associated with these genetic polymorphisms.

The potential impact of P53 and APO-1 genetic polymorphisms on hepatitis C genotype 4a susceptibility

The hepatitis C virus (HCV), the main cause of morbidity and mortality, is endemic worldwide. HCV causes cirrhosis and other complications that often lead to death. HCV is most common in underdeveloped nations, with the highest prevalence rates in Egypt. Tumor suppressor gene (P53) induces the expression of apoptotic antigen-1 gene (APO-1) by binding to its promoter for mediating apoptosis; an important mechanism for limiting viral replication. This study aims at investigating the impact of P53 72 Arg/Pro and APO-1 -670 A/G polymorphisms on HCV genotype 4a susceptibility. Two hundred and forty volunteers were enrolled in this study and divided into two major groups; 160 HCV infected patient group and 80 healthy control group. HCV patients were classified according to Metavir scoring system into two subgroups; 72 patients in F0/1-HCV subgroup (patients with no or mild fibrotic stages) and 38 patients in F3/4-HCV subgroup (patients with advanced fibrotic stages). Quantification of HCV-RNA by qRT-PCR and fibrotic scores as well as genotyping of HCV-RNA, P53 at 72 Arg/Pro, and APO-1 at -670 A/G were performed for all subjects. It was resulted that F0/1-HCV patients have significant differences of P53 at 72 (Pro/Pro and Arg/Arg) genotypes and dominant/recessive genetic models as well as APO-1 -670 A/A genotype and dominant genetic model as compared to F3/4-HCV patients. Moreover, HCV patients have significant differences of P53 at 72 (Pro/Pro) genotype and recessive genetic model as well as APO-1 -670 A/A genotype and dominant genetic model as compared to those of healthy individuals. Finally, it was concluded that P53 rs 1042522 (Pro/Pro and Arg/Arg) genotypes and APO-1 rs 1800682 A/A genotype may be potentially used as sensitive genetic markers for HCV genotype 4a susceptibility.

Association between the FAS rs2234767G/A polymorphism and cancer risk: a systematic review and meta-analysis

Abnormal regulation of apoptosis can lead to carcinogenesis. Single nucleotide polymorphisms in apoptotic genes have been associated with cancer risk, such as the FAS rs2234767G/A polymorphism, which alters transcription of the FAS promoter. Downregulation of FAS, with resultant cellular resistance to death signals, has been found in many cancers. However, the association between the FAS rs2234767G/A polymorphism and cancer risk is still controversial. Here, we performed a meta-analysis including 41 articles (44 case-control studies, 17,814 cases and 24,307 controls) identified from PubMed and Chinese language (CNKI and WanFang) databases related to cancer susceptibility and the FAS rs2234767G/A polymorphism. We used odds ratios (ORs) and 95% confidence intervals (CIs) to assess the strength of the associations. We found that the rs2234767 G-allele was a protective factor for cancer risk (GG vs. AA: OR=0.88, 95% CI=0.79-0.98; GG+GA vs. AA: OR=0.87, 95% CI=0.79-0.96). Similar associations were detected in the "source of control", ethnicity, and cancer type subgroups. Further studies on a larger sample size and considering gene-environment interactions should be conducted to confirm the role of FAS polymorphisms, especially rs2234767G/A, in cancer risk.

Apoptosis-related Fas and FasL gene polymorphisms' associations with knee osteoarthritis

To investigate the associations between Fas and FasL gene polymorphisms and susceptibility to knee osteoarthritis. Genomic DNA was obtained from 146 patients with knee osteoarthritis and 102 healthy controls. Genotype distributions and allelic frequencies of four polymorphisms of Fas (-670 G>A rs1800682, -1377 G>A rs2234767) and FasL (IVS2nt-124 A>G rs5030772, -844 T>C rs763110) genes were compared between the groups. Thereafter, this association was investigated between patients and controls of the same sex. There were significant differences between patients with knee osteoarthritis and controls regarding the genotype distributions and allelic frequencies of Fas-1377 G>A polymorphism (P = 0.0001 and P = 0.005, respectively). The Fas-1377 GG genotype and G allele were significantly more frequent in patients with knee osteoarthritis than in controls. Genotype distributions and allelic frequencies of Fas-670 G>A, FasL-844 T>C, and FasL IVS2nt-124 A>G polymorphisms did not differ between the groups (P > 0.05). However, there were no significant differences between patients and controls of the same sex (P > 0.05). These findings suggest that the Fas-1377 G>A polymorphism in the Fas gene related with apoptosis may contribute to susceptibility to knee osteoarthritis in the Turkish population. There is a need for further studies to evaluate the role of apoptosis in large cohorts.

Functional polymorphisms in cell death pathway genes FAS and FAS ligand and risk of prostate cancer in a Chinese population

BACKGROUND

Apoptosis is the physiological mechanism of programmed cell death and abnormal regulation of this pathway can lead to carcinogenesis. We hypothesized that the FAS -1377G>A, -670A>G, and FASL -844T>C polymorphisms are associated with risk of prostate cancer (PCa).

MATERIALS AND METHODS

We genotyped polymorphisms in a hospital-based case-control study of 602 patients diagnosed with PCa and 703 cancer-free controls in a Chinese population using polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

We found a significantly decreased risk associated with FAS -1377GA [adjusted odds ratio (OR) = 0.71, 95% confidence interval (CI) = 0.56-0.90] genotype compared with the -1377GG genotype and decreased risk associated with FAS -670AG and -670GG genotypes (OR 0.75, 95% CI: 0.59-0.95; OR 0.70, 95% CI: 0.50-0.96) compared with the -670AA genotype. Consistently, we found that individuals carrying haplotype genotype with 0 or 1 risk allele (-1377G and -670A) had a lower risk of PCa than those with two risk alleles (OR 0.48, 95% CI: 0.28-0.80; OR 0.60, 95% CI: 0.41-0.87; OR 0.82, 95% CI: 0.69-0.97 for the AA, GG, and AG haplotype, respectively). In addition, when we evaluated these two FAS polymorphisms together, we found that the combined genotype with 4 risk alleles was associated with a significantly increased risk of PCa compared with those with 0-3 variants (OR 1.51, 95% CI: 1.19-1.91), and this increased risk was more pronounced among subgroups of Gleason score <7 and >7, and PSA > 20 ng/ml (OR 1.49, 95% CI: 1.08-2.04; OR 1.72, 95% CI: 1.25-2.44; OR 1.61, 95% CI: 1.23-2.13, respectively).

CONCLUSIONS

These results suggested that the FAS polymorphisms may contribute to PCa risk in a Chinese population.

Apoptosis gene polymorphisms, age, smoking and the risk of non-small cell lung cancer

Apoptosis is important for targeting cancer cells for destruction. Various single-nucleotide polymorphisms (SNPs) in apoptotic genes have been associated with increased risks in lung cancer, particularly FAS -1377 G>A (rs2234767), FASLG -844 C>T (rs763110), IL1B +3954 C>T Phe105Phe (rs1143634) and BAT3 Ser625Pro (rs1052486). We studied the association of these SNPs with non-small cell lung cancer (NSCLC) in a large case-control study (N = 4263: 2644 cases and 1619 controls). No associations with NSCLC were observed in the main effects analysis for all four SNPs, adjusting for age, gender, smoking status, pack-years and years since smoking cessation. In subjects under age 60, for FASLG -844 C>T polymorphism, CT compared with the CC genotype, was significantly associated with increased risk of NSCLC, adjusted odds ratio (aOR) = 1.58 (1.22, 2.05), P = 0.0006 and TT aOR = 1.45 (1.01, 2.04), P = 0.04. In contrast, for those over age 60, the CT aOR = 0.91 (0.73, 1.13), P = 0.37 and TT aOR = 0.86 (0.64, 1.16), P = 0.32. The P-value for the age-genotype interaction was 0.004. For the IL1B +3954 C>T polymorphism, compared with the CC genotype, TT showed significant associations in former smokers and in men but tests of interaction were not significant (P(smoking) = 0.24, P(gender) = 0.17). No interactions were observed for FAS -1377 G>A and BAT3 Ser625Pro polymorphisms. Our findings indicate that age and smoking may modify the association of the FASLG -844 and IL1B + 3954 SNPs with the risk of NSCLC.