Association of GSTT1 gene polymorphisms with the risk of prostate cancer: an updating meta-analysis

Association of CYP1A1, GSTM1 and GSTT1 gene polymorphisms with risk of prostate cancer in Algerian population

Background

Prostate cancer is the most common cancer in the world, and its etiology involves the interaction of genetic and environmental factors. Interindividual differences observed in the metabolism of xenobiotics may be due to polymorphisms of genes encoding the detoxification enzymes. This genetic variability seems to be associated with differences in susceptibility to certain types of cancers, including prostate cancer. Our study has been made in order to investigate a possible genetic predisposition to prostate cancer in an Algerian population, through the analysis of genetic polymorphisms of three enzymes metabolizing xenobiotics namely cytochrome P450 (CYP) 1A1, glutathione S-transferase mu 1 (GSTM1) and GST theta 1 (GSTT1).

Methods

The current case–control study included 101 prostate cancer patients and 101 healthy controls. Genotyping of CYP1A1 T3801C polymorphisms and GSTM1/GSTT-null was made, respectively, by PCR-RFLP and multiplex PCR.

Results

No significantly positive associations were found for the CYP1A1 T3801C [p = 0.71, OR = 1.23 (0.56–2.72)] and GSTM1-null [p = 0.26, OR = 1.37 (0.76–2.4)] polymorphisms and prostate cancer susceptibility. However, we detect a highly significant association between GSTT1-null genotype [p = 0.03, OR = 2.03 (1.06–3.99)], GSTM1/GSTT1-double null genotype [p = 0.027, OR = 2.6; CI (1.07–6.5)] and prostate cancer risk. Furthermore, no statistically significant differences between the studied polymorphisms and tumor parameters (the Gleason score and clinical stages of aggressiveness) at diagnosis of PCa.

Conclusions

The risk of developing prostate cancer in Algeria does not appear to be associated with CYP1A1 T3801C genotypes and GSTM1-null, but GSTT1-null and GSTM1/GSTT1-double null genotypes increased the risk of prostate cancer.

GSTT1 Null Genotype and Susceptibility to Children Acute Leukemia in Chinese Population: Evidence from a Meta-Analysis

Objectives:

Increasing number of studies has focused on studying the relationship between glutathione S-transferase T1 polymorphism and children acute leukemia, among which discrepancies have risen. The aim of this study is to provide a more exact assessment of glutathione S-transferase T1 polymorphism and children acute leukemia among certain Chinese population.

Methods:

Studies were identified using PubMed, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure and Chinese Biology Medicine from beginning to July 2018. The strength of association was quantified by pooling odds ratios and 95% confidence intervals using fixed-effect or random-effect model according to the heterogeneity.

Results:

Overall, a positive relationship was found in null genotype of glutathione S-transferase T1 polymorphism on the risk of childhood acute leukemia among all Chinese populations (odds ratios: 1.52; 95% confidence intervals = 1.19-1.94). Similarly, consistent results were found in subgroup of Southern China (odds ratios: 1.48; 95% confidence intervals: 1.08-2.02), Northern China (odds ratios: 1.59; 95% confidence intervals: 1.09-2.33), acute lymphoblastic leukemia (odds ratios: 1.61; 95% confidence intervals: 1.19-2.17), “age > 18 years” (odds ratios: 1.59; 95% confidence intervals: 1.09-2.33), “age < 18 years” (odds ratios: 1.48; 95% confidence intervals: 1.08-2.02), and population-based studies (odds ratios: 1.60; 95% confidence intervals: 1.16-2.20).

Conclusions:

Collectively, finding from the current study indicated that GSTT1 null polymorphism may be susceptible on childhood acute leukemia among Chinese.

Characterization of Phase I and Phase II Hepatic Metabolism and Reactive Intermediates of Larrea nitida Cav. and Its Lignan Compounds

Larrea nitida Cav. (LNC), which belongs to the family Zygophyllaceae, is widely indigenous and used in South America to treat various pathological conditions. It contains the antioxidant and antiinflammatory but toxic nordihydroguaiaretic acid (NDGA) as well as O-methylated metabolite of NDGA (MNDGA) as bioactive compounds. The hepatic metabolism-based toxicological potential of extracts of LNC (LNE), NDGA, and MNDGA has not previously been reported. The present study aimed to characterize the phase I and phase II hepatic metabolism and reactive intermediates of LNE, NDGA, and MNDGA and their effects on the major drug-metabolizing enzymes in vitro and ex vivo. A methanol extract of LNC collected from Chile as well as NDGA and MNDGA isolated from LNE were subjected to metabolic stability assays in liver microsomes in the presence of the cofactors reduced nicotinamide dinucleotide phosphate (NADPH) and/or uridine 5'-diphosphoglucuronic acid (UDPGA). Cytochrome P450 (CYP) inhibition assays were performed using CYP isozyme-specific model substrates to examine the inhibitory activities of LNE, NDGA, and MNDGA, which were expressed as % inhibition and IC₅₀ values. Ex vivo CYP induction potential was investigated in the liver microsomes prepared from the rats intraperitoneally administered with LNE. Glutathione (GSH) adduct formation was monitored by LC-MS³ analysis of the microsomal incubation samples with either NDGA or MNDGA and an excess of GSH to determine the formation of electrophilic reactive intermediates. Both NDGA and MNDGA were stable to NADPH-dependent phase I metabolism, but labile to glucuronide conjugation. LNE, NDGA, and MNDGA showed significant inhibitory effects on CYP1A2, 2C9, 2D6, and/or 3A4, with IC₅₀ values in the micromolar range. LNE was found to be a CYP1A2 inducer in ex vivo rat experiments, and mono- and di-GSH adducts of both NDGA and MNDGA were identified by LC-MS³ analysis. Our study suggests that hepatic clearance is the major elimination route for the lignans NDGA and MNDGA present in LNE. These lignans may possess the ability to modify biomacromolecules via producing reactive intermediates. In addition, LNE, NDGA, and MNDGA are found to be inhibitors for various CYP isozymes such as CYP2C9 and 3A4. Thus, the consumption of LNC as an herbal preparation or NDGA may cause metabolism-driven herb-drug interactions. Copyright © 2016 John Wiley & Sons, Ltd.

GSTM1 polymorphism contribute to colorectal cancer in Asian populations: a prospective meta-analysis

Glutathione S-transferases (GSTs) are enzymes which expressed in many tissues and play important roles in neutralization of toxic compounds, and protecting hosts against cancer. Among several GSTs, Glutathione S-transferases mu (GSTM) has been drawn attention upon the association with the genetic risk for many types of cancers. But whether the GSTM1 polymorphisms confer the susceptibility to colorectal cancer in Asians has not been well established. We searched the PubMed database with GSTM1, polymorphism and colorectal cancer, attempting to identify the eligible studies. In total, 33 case-control studies in Asian populations with 8502 colorectal cancer patients and 13699 controls were included in the current meta-analysis. The association between the polymorphism and susceptibility to colorectal cancer was evaluated by the odds ratio (OR) and 95% confidence intervals (CI). The pooled meta-analysis suggested that GSTM1 null variant was correlated to the colorectal cancer risk in Asians. There was a marginal heterogeneity among these eligible studies. Nevertheless, cumulative meta-analysis observed a trend of an obvious association between the GSTM1 null genotype and colorectal cancer risk in Asians. In summary, the meta-analysis suggested that GSTM1 null polymorphism confer the susceptibility to colorectal cancer in Asians, especially in Chinese populations.

Effect of GSTM1 null genotype on risk of childhood acute leukemia: a meta-analysis

Glutathione S-transferases are important enzymes in the detoxification of a wide range of reactive oxygen species. Recently, there have been a number of studies on the association between Glutathione S-transferase M1 (GSTM1) null genotype and childhood acute leukemia in Chinese, but the results of previous reports are inconsistent. Thus, we performed a meta-analysis to clarify the effect of GSTM1 null genotype on childhood acute leukemia risk. PubMed, Embase, and Wanfang databases were searched to identify case–control studies investigating the association between GSTM1 null genotype and risk of childhood acute leukemia. Between-study heterogeneity was assessed using the I2 statistic method. Odds ratios (OR) with corresponding 95% confidence intervals (95% CI) were pooled to assess the association. Seven case–control studies were finally included in the meta-analysis. There was no between-study heterogeneity among those seven studies (I2 = 0%). Overall, the GSTM1 null genotype was significantly associated with increased risk of childhood acute leukemia in Chinese (fixed effect OR = 2.49; 95% CI, 1.84–3.37; P < 0.001). The cumulative meta-analyses showed a trend of more obvious association between GSTM1 null genotype and risk of childhood acute leukemia in Chinese as data accumulated by year. Sensitivity analysis by omitting single study in turns also did not materially alter the pooled ORs. Therefore, the GSTM1 null genotype is significantly associated with increased risk of childhood acute leukemia in Chinese.

GSTT1 genetic polymorphism and susceptibility to childhood acute lymphoblastic leukemia: a meta-analysis

Glutathione S-transferase T1 (GSTT1) genetic polymorphism has been considered as a risk factor for developing malignant diseases including acute lymphoblastic leukemia; however, the results from previous studies are inconsistent. We performed a meta-analysis of 16 published studies to investigate the association between GSTT1 null variant and risk of acute lymphoblastic leukemia in childhood. Between-study heterogeneity was assessed using the I (2) statistic method. Odds ratios (ORs) with corresponding 95 % confidence intervals (95 %CI) were pooled to assess the association. Those 16 studies were from 14 publications and included a total of 2,424 cases and 3,447 controls. Meta-analysis of a total of 16 studies showed that GSTT1 null variant was significantly associated with risk of childhood acute lymphoblastic leukemia (fixed-effect OR = 1.22, 95 %CI 1.07-1.39, P = 0.003, I (2) = 35 %). Subgroup analysis showed that GSTT1 null variant was significantly associated with risk of childhood acute lymphoblastic leukemia in Asians (fixed-effect OR = 1.47, 95 %CI 1.16-1.85, P = 0.001, I (2) = 0 %). However, there was no obvious association in both Caucasians (random-effect OR = 1.07, 95 %CI 0.83-1.38, P = 0.59, I (2) = 53 %) and Africans (random-effect OR = 0.99, 95 %CI 0.31-3.10, P = 0.98, I (2) = 72 %). Therefore, the GSTT1 null variant is significantly associated with susceptibility to childhood acute lymphoblastic leukemia in Asians.

Glutathione S-transferase M1 polymorphism and colorectal cancer risk in Chinese population

Glutathione S-transferase M1 (GSTM1) polymorphism has been proven to be associated with risks of several cancers. However, previous studies on the association between GSTM1 polymorphism and colorectal cancer risk in Chinese population reported controversial results. We performed a meta-analysis of 13 studies which were identified through the literature search in PubMed and Wanfang databases. The strength of the association between GSTM1 polymorphism and colorectal cancer risk was measured by odds ratio (OR) with corresponding 95% confidence interval (95% CI). Overall, GSTM1 null mutation was significantly associated with a risk of colorectal cancer in Chinese population (OR = 1.37, 95% CI 1.12 to 1.68, P = 0.002). Sensitivity analyses by omitting those studies in turns did not materially alter the overall pooled ORs. The cumulative meta-analyses further showed a trend of an obvious association between GSTM1 null mutation and risk of colorectal cancer in Chinese population as information accumulated by year. The findings from our meta-analysis suggest that GSTM1 null mutation is significantly associated with a risk of colorectal cancer in Chinese population.