GSTM1 and GSTT1 polymorphism and susceptibility to esophageal cancer in high- and low-risk regions of India

Health effects associated with chewing tobacco: a Burden of Proof study

Chewing tobacco use poses serious health risks; yet it has not received as much attention as other tobacco-related products. This study synthesizes existing evidence regarding the health impacts of chewing tobacco while accounting for various sources of uncertainty. We conducted a systematic review and meta-analysis of chewing tobacco and seven health outcomes, drawing on 103 studies published from 1970 to 2023. We use a Burden of Proof meta-analysis to generate conservative risk estimates and find weak-to-moderate evidence that tobacco chewers have an increased risk of stroke, lip and oral cavity cancer, esophageal cancer, nasopharynx cancer, other pharynx cancer, and laryngeal cancer. We additionally find insufficient evidence of an association between chewing tobacco and ischemic heart disease. Our findings highlight a need for policy makers, researchers, and communities at risk to devote greater attention to chewing tobacco by both advancing tobacco control efforts and investing in strengthening the existing evidence base.

Purification and Identification of Antioxidant Peptides from Rice Fermentation of Lactobacillus plantarum and Their Protective Effects on UVA-Induced Oxidative Stress in Skin

Oxidative stress is an important factor on both aging and disease. Among foods endowed with beneficial healthy properties, rice is a very useful material, not only because it has a good amino acid ratio and produces antioxidant peptides through microbial fermentation, but also for its inexpensive availability. In this study, rice was treated with Lactobacillus plantarum, and the resulting mixture of small peptides with less than 11 amino acids (RFP) was extracted and purified from the fermentation broth. Subsequently, the antioxidant activity of RFP was assessed using the chemical model, cell biology, and animal model methods. RFP enhanced the expression of the antioxidant enzyme genes downstream of the KEAP1-NRF2/ARE pathway by promoting nuclear factor-erythroid 2-related factor 2 (NRF2) nuclear translocation while simultaneously removing lipid oxidation products and excess free radicals. These results suggest that RFP is a potential substance for resisting aging and disease caused by oxidative stress.

Glutathione S-transferasesP1 AA (105Ile) allele increases oral cancer risk, interacts strongly with c-Jun Kinase and weakly detoxifies areca-nut metabolites

The Glutathione S-transferases (GSTs) protects cellular DNA against oxidative damage. The role of GSTP1 polymorphism (A313G; Ile105Val) as a susceptibility factor in oral cancer was evaluated in a hospital-based case-control study in North-East India, because the habit of chewing raw areca-nut (RAN) with/without tobacco is common in this region. Genetic polymorphism was investigated by genotyping 445 cases and 444 controls. Individuals with the GSTP1 AA-genotype showed association with the oral cancer (OR = 3.1, 95% CI = 2.4–4.2, p = 0.0002). Even after adjusting for age, sex and habit the AA-genotype is found to be significantly associated with oral cancer (OR = 2.4, 95% CI = 1.7–3.2, p = 0.0001). A protein-protein docking analysis demonstrated that in the GG-genotype the binding geometry between c-Jun Kinase and GSTP1 was disrupted. It was validated by immunohistochemistry in human samples, showing lower c-Jun-phosphorylation and down-regulation of pro-apoptotic genes in normal oral epithelial cells with the AA-genotype. In silico docking revealed that AA-genotype weakly detoxifies the RAN/tobacco metabolites. In addition, experiments revealed a higher level of 8-Oxo-2′-deoxyguanosine induction in tumor samples with the AA-genotype. Thus, habit of using RAN/tobacco and GSTP1 AA-genotype together play a significant role in predisposition to oral cancer risk by showing higher DNA-lesions and lower c-Jun phosphorylation that may inhibit apoptosis.

Association between the Glutathione-S-transferase T1 null genotype and esophageal cancer susceptibility: a meta-analysis involving 11,163 subjects

Background

Glutathione-S-Transferase T1 (GSTT1) null genotype has been shown to be associated with the risk of esophageal cancer. However, the results remain inconsistent. Thus a comprehensive meta-analysis was conducted to assess the strength of association between GSTT1 null genotype and the risk of esophageal cancer.

Materials and Methods

A literature search of PubMed, Embase, China National Knowledge Infrastructure (CNKI) and Wanfang databases up to March 31, 2017 was conducted and 30 eligible articles with 4482 cases and 6681 controls were finally recruited. The strength of correlation between GSTT1 polymorphism and the susceptibility of esophageal cancer was assessed by the crude odds ratios (ORs) with 95% confidence intervals (CIs). Subgroup analyses and sensitivity analyses were performed to further identify the association.

Results

GSTT1 null genotype significantly increased the risk of esophageal cancer (OR = 1.20; 95% CI 1.04-1.40; P < 0.05). In a subgroup analysis by ethnicity, GSTT1 null genotype was correlated with a significantly increased risk of esophageal cancer among Asians (OR = 1.33; 95% CI 1.12-1.58; P < 0.05), instead of Caucasians or Africans (OR = 0.91; 95% CI 0.65-1.26; P > 0.05 for Caucasians and OR = 1.32; 95% CI 0.98-1.77; P > 0.05 for Africans). In the analysis by histological type, GSTT1 null genotype was correlated with a significantly increased risk of esophageal squamous cell carcinoma (OR = 1.34; 95% CI 1.12-1.61; P < 0.05), particularly among Asians (OR = 1.54; 95% CI 1.30-1.82; P < 0.05), but not among Caucasians or Africans (OR = 0.87; 95% CI 0.48-1.57; P > 0.05 for Caucasians and OR = 1.32; 95% CI 0.98-1.77; P > 0.05 for Africans). In addition, there is no significant correlation between GSTT1 null genotype and the risk of esophageal adenocarcinoma (OR = 0.98; 95% CI 0.71-1.35; P > 0.05).

Conclusions

Our findings demonstrate that GSTT1 null genotype significantly increases esophageal cancer risk, particularly in Asians.

Metabolic Phase I (CYPs) and Phase II (GSTs) Gene Polymorphisms and Their Interaction with Environmental Factors in Nasopharyngeal Cancer from the Ethnic Population of Northeast India

Multiple genetic and environmental factors and their interaction are believed to contribute in the pathogenesis of Nasopharyngeal Cancer (NPC). We investigate the role of Metabolic Phase I (CYPs) and Phase II (GSTs) gene polymorphisms, gene-gene and gene-environmental interaction in modulating the susceptibility to NPC in Northeast India. To determine the association of metabolic gene polymorphisms and environmental habits, 123 cases and 189 controls blood/swab samples were used for PCR and confirmed by Sanger sequencing. Analysis for GSTM1 and GSTT1 gene polymorphism was done by multiplex PCR. The T3801C in the 3'- flanking region of CYP1A1 gene was detected by PCR-RFLP method. The Logistic regression analysis was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI). The GSTM1 null genotype alone (OR = 2.76) was significantly associated with NPC risk (P < 0.0001). The combinations of GSTM1 null and GSTT1 null genotypes also higher, 3.77 fold (P < 0.0001), risk of NPC, while GSTM1 null genotype along with CYP1A1 T3801C TC + CC genotype had 3.22 (P = 0.001) fold risk. The most remarkable risk was seen among individual carrying GSTM1 null, GSTT1 null genotypes and CYP1A1 T3801C TC + CC genotypes (OR = 5.71, P = 0.001). Further; analyses demonstrate an enhanced risk of NPC in smoked meat (OR = 5.56, P < 0.0001) and fermented fish consumers (OR = 5.73, P < 0.0001) carrying GSTM1 null genotype. An elevated risk of NPC was noted in smokers (OR = 12.67, P < 0.0001) and chewers (OR = 5.68, P < 0.0001) with GSTM1 null genotype. However, smokers had the highest risk of NPC among individuals carrying GSTT1 null genotype (OR = 4.46, P = 0.001) or CYP1A1 T3801C TC + CC genotype (OR = 7.13, P < 0.0001). The association of null genotypes and mutations of metabolic neutralizing genes along with the environmental habits (tobacco smokers and chewers, smoke meat, fermented fishes) can be used as a possible biomarker for early detection and preventive measure of NPC.

Alteration in the expression of MGMT and RUNX3 due to non-CpG promoter methylation and their correlation with different risk factors in esophageal cancer patients

Promoter methylation reflects in the inactivation of different genes like O⁶-methylguanine-DNA methyltransferase DNA repair gene and runt-related transcription factor 3, a known tumor suppressor gene in various cancers such as esophageal cancer. The promoter methylation was evaluated for O⁶-methylguanine-DNA methyltransferase and runt-related transcription factor 3 in CpG, CHH, and CHG context (where H is A, T, or C) by next-generation sequencing. The methylation status was correlated with quantitative messenger RNA expression. In addition, messenger RNA expression was correlated with different risk factors like tobacco, alcohol, betel nut consumption, and smoking habit. CpG methylation of O⁶-methylguanine-DNA methyltransferase promoter had a positive association in the development of esophageal cancer (p < 0.05), whereas runt-related transcription factor 3 promoter methylation showed no significant association (p = 1.0) to develop esophageal cancer. However, the non-CpG methylation, CHH, and CHG were significantly correlated with O⁶-methylguanine-DNA methyltransferase (p < 0.05) and runt-related transcription factor 3 (p < 0.05) promoters in the development of esophageal cancer. The number of cytosine converted to thymine (C→T) in O⁶-methylguanine-DNA methyltransferase promoter showed a significant correlation between cases and controls (p < 0.05), but in runt-related transcription factor 3 no such significant correlation was observed. Besides, messenger RNA expression was found to be significantly correlated with promoter hypermethylation of O⁶-methylguanine-DNA methyltransferase and runt-related transcription factor 3 in the context of CHG and CHH (p < 0.05). The CpG hypermethylation in O⁶-methylguanine-DNA methyltransferase showed positive (p < 0.05) association, whereas in runt-related transcription factor 3, it showed contrasting negative association (p = 0.23) with their messenger RNA expression. Tobacco, betel nut consumption, and smoking habits were associated with altered messenger RNA expression of O⁶-methylguanine-DNA methyltransferase (p < 0.05) and betel nut consumption and smoking habits were associated with runt-related transcription factor 3 (p < 0.05). There was no significant association between messenger RNA expression of O⁶-methylguanine-DNA methyltransferase and runt-related transcription factor 3 with alcohol consumption (p = 0.32 and p = 0.15). In conclusion, our results suggest that an aberrant messenger RNA expression may be the outcome of CpG, CHG, and CHH methylation in O⁶-methylguanine-DNA methyltransferase, whereas outcome of CHG and CHH methylation in runt-related transcription factor 3 promoters along with risk factors such as consumption of tobacco, betel nut, and smoking habits in esophageal cancer from Northeast India.

Influence of the CYP1A1 T3801C Polymorphism on Tobacco and Alcohol-Associated Head and Neck Cancer Susceptibility in Northeast India

BACKGROUND

Tobacco and alcohol contain or may generate carcinogenic compounds related to cancers. CYP1A1 enzymes act upon these carcinogens before elimination from the body. The aim of this study was to investigate whether CYP1A1 T3801C polymorphism modulates the relationship between tobacco and alcohol- associated head and neck cancer (HNC) susceptibility among the northeast Indian population.

MATERIALS AND METHODS

One hundred and seventy histologically confirmed HNC cases and 230 controls were included within the study. The CYP1A1 T3801C polymorphism was determined using PCR-RFLP, and the results were confirmed by DNA sequencing. Logistic regression (LR) and multifactor dimensionality reduction (MDR) approaches were applied for statistical analysis.

RESULTS

The CYP1A1 CC genotype was significantly associated with HNC risk (P=0.045). A significantly increased risk of HNC (OR=6.09; P<0.0001) was observed in individuals with combined habits of smoking, alcohol drinking and tobacco-betel quid chewing. Further, gene-environment interactions revealed enhanced risks of HNC among smokers, alcohol drinkers and tobacco-betel quid chewers carrying CYP1A1 TC or CC genotypes. The highest risk of HNC was observed among smokers (OR=7.55; P=0.009) and chewers (OR=10.8; P<0.0001) carrying the CYP1A1 CC genotype. In MDR analysis, the best model for HNC risk was the three-factor model combination of smoking, tobacco-betel quid chewing and the CYP1A1 variant genotype (CVC=99/100; TBA=0.605; P<0.0001); whereas interaction entropy graphs showed synergistic interaction between tobacco habits and CYP1A1.

CONCLUSIONS

Our results confirm that the CYP1A1 T3801C polymorphism modifies the risk of HNC and further demonstrated importance of gene-environment interaction.

Glutathione S-transferase M1 polymorphism and esophageal cancer risk: An updated meta-analysis based on 37 studies

AIM: To evaluate the relationship between glutathione S-transferase M1 (GSTM1) polymorphism and susceptibility to esophageal cancer (EC).

METHODS: A comprehensive search of the United States National Library of Medicine PubMed database and the Elsevier, Springer, and China National Knowledge Infrastructure databases for all relevant studies was conducted using combinations of the following terms: “glutathione S-transferase M1”, “GSTM1”, “polymorphism”, and “EC” (until November 1, 2014). The statistical analysis was performed using the SAS software (v.9.1.3; SAS Institute, Cary, NC, United States) and the Review Manager software (v.5.0; Oxford, England); crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the association between the GSTM1 null genotype and the risk of EC.

RESULTS: A total of 37 studies involving 2236 EC cases and 3243 controls were included in this meta-analysis. We observed that the GSTM1 null genotype was a significant risk factor for EC in most populations (OR = 1.33, 95%CI: 1.12-1.57, P_{heterogeneity} < 0.000001, and I² = 77.0%), particularly in the Asian population (OR = 1.53, 95%CI: 1.26-1.86, P_{heterogeneity} < 0.000001, and I² = 77.0%), but not in the Caucasian population (OR = 1.02, 95%CI: 0.87-1.19, P_{heterogeneity} = 0.97, and I² = 0%).

CONCLUSION: The GSTM1 null polymorphism may be associated with an increased risk for EC in Asian but not Caucasian populations.

Gene-environment interactions in esophageal cancer

Esophageal cancer (EC) is one of the most common malignancies in low- and medium-income countries and represents a disease of public health importance because of its poor prognosis and high mortality rate in these regions. The striking variation in the prevalence of EC among different ethnic groups suggests a significant contribution of population-specific environmental and dietary factors to susceptibility to the disease. Although individuals within a demarcated geographical area are exposed to the same environment and share similar dietary habits, not all of them will develop the disease; thus genetic susceptibility to environmental risk factors may play a key role in the development of EC. A wide range of xenobiotic-metabolizing enzymes are responsible for the metabolism of carcinogens introduced via the diet or inhaled from the environment. Such dietary or environmental carcinogens can bind to DNA, resulting in mutations that may lead to carcinogenesis. Genes involved in the biosynthesis of these enzymes are all subject to genetic polymorphisms that can lead to altered expression or activity of the encoded proteins. Genetic polymorphisms may, therefore, act as molecular biomarkers that can provide important predictive information about carcinogenesis. The aim of this review is to discuss our current knowledge on the genetic risk factors associated with the development of EC in different populations; it addresses mainly the topics of genetic polymorphisms, gene-environment interactions, and carcinogenesis. We have reviewed the published data on genetic polymorphisms of enzymes involved in the metabolism of xenobiotics and discuss some of the potential gene-environment interactions underlying esophageal carcinogenesis. The main enzymes discussed in this review are the glutathione S-transferases (GSTs), N-acetyltransferases (NATs), cytochrome P450s (CYPs), sulfotransferases (SULTs), UDP-glucuronosyltransferases (UGTs), and epoxide hydrolases (EHs), all of which have key roles in the detoxification of environmental and dietary carcinogens. Finally, we discuss recent advances in the study of genetic polymorphisms associated with EC risk, specifically with regard to genome-wide association studies, and examine possible challenges of case-control studies that need to be addressed to better understand the interaction between genetic and environmental factors in esophageal carcinogenesis.

Interaction between GSTT1 and GSTP1 allele variants as a risk modulating-factor for autism spectrum disorders

We investigated the role of glutathione S-transferase (GST) genes in Autism Spectrum Disorder (ASD). We used data from 111 pairs of age- and sex-matched ASD cases and typically developing (TD) controls between 2-8 years of age from Jamaica to investigate the role of GST pi 1 (GSTP1), GST theta 1 (GSTT1), and GST mu 1 (GSTM1) polymorphisms in susceptibility to ASD. In univariable conditional logistic regression models we did not observe significant associations between ASD status and GSTT1, GSTM1, or GSTP1 genotype (all P > 0.15). However, in multivariable conditional logistic regression models, we identified a significant interaction between GSTP1 and GSTT1 in relation to ASD. Specifically, in children heterozygous for the GSTP1 Ile105Val polymorphism, the odds of ASD was significantly higher in those with the null GSTT1 genotype than those with the other genotypes [Matched Odds Ratio (MOR) = 2.97, 95% CI (1.09, 8.01), P = 0.03]. Replication in other populations is warranted.

Association between GSTM1 and GSTT1 polymorphisms and esophageal squamous cell carcinoma: results from a case-control study in Kashmir, India

Polymorphisms in glutathione-S-transferases (GSTs), the phase II xenobiotic detoxifying enzymes, have been associated with increased cancer risk. In this study, we assessed the association of functional polymorphisms in GSTM1 and GSTT1 with esophageal cancer in Kashmir, India, an area with a high incidence of esophageal squamous cell carcinoma (ESCC). We analyzed genotypes of GSTM1 and GSTT1 using a multiplex PCR in 492 pairs of ESCC cases and individually matched controls. The associations between polymorphisms in these genes and ESCC risk were examined by conditional logistic regression models adjusted for multiple potential confounders. In addition, the interaction between these genes and several environmental exposures with regard to ESCC risk was assessed. Our results showed an association between the GSTT1 null genotype and ESCC risk (odds ratio (OR) = 1.58; 95% confidence interval (CI) 1.04-2.39). Although GSTM1 alone was not associated with ESCC risk, individuals with the GSTM1 (-)/GSTT1 (+) genotype showed an inverse relation with ESCC risk (OR = 0.55; 95% CI 0.32-0.93), compared to GSTM1 (+)/GSTT1 (+) individuals. We found a significant interaction between the GSTT1 and GSTM1 genotypes with regard to ESCC risk (P = 0.001); however, there were no interactions between environmental factors and GSTT1 and GSTM1 genotypes. This study indicates that GSTT1 null genotype is associated with ESCC risk in Kashmiri population. The association between GSTM1 and ESCC risk needs further investigations. Interactions of these genotypes with environmental exposures should be examined in multicentric studies with bigger sample sizes.