Molecular docking and ANS-displacement experiments indicated that 8-anilinonaphthalene sulfonate (ANS) binds the hydrophobic site (H-site) in the active site of dimeric class Mu rGST M1-1. The naphthalene moiety provides most of the van der Waals contacts at the ANS-binding interface while the anilino group is able to sample different rotamers. The energetics of ANS binding were studied by isothermal titration calorimetry (ITC) over the temperature range of 5-30 degrees C. Binding is both enthalpically and entropically driven and displays a stoichiometry of one ANS molecule per subunit (or H-site). ANS binding is linked to the uptake of 0.5 protons at pH 6.5. Enthalpy of binding depends linearly upon temperature yielding a DeltaC(p) of -80+/-4 cal K(-1) mol(-1) indicating the burial of solvent-exposed nonpolar surface area upon ANS-protein complex formation. While ion-pair interactions between the sulfonate moiety of ANS and protein cationic groups may be significant for other ANS-binding proteins, the binding of ANS to rGST M1-1 is primarily hydrophobic in origin. The binding properties are compared with those of other GSTs and ANS-binding proteins.

The distribution of the polymorphic alleles of the genes coding for glutathione S-transferases (GSTs) M1 and T1 was compared with the results of cytological grading of exfoliated urothelial cells (Pap test) in a non-diseased high-risk group of workers formerly exposed to benzidine in the Shanghai dyestuff industry (n = 317). All subjects were genotyped for GSTT1 and M1 gene polymorphism by allele-specific PCR. Individuals were stratified according to their job and duration of exposure. A subgroup of 78 individuals with cytological gradings of grade III or higher in the Pap test showed a significant under-representation of the combination of GSTT1 0/0 and M1 0/0 genotypes compared with 238 subjects with a cytological classification lower than grade III (OR 0.55, 95% CI 0.31-0.98. P=0.04). These results suggest that neither the GSTM1 0/0 or GSTT1 0/ 0 genotype alone nor their combination had a clear association with cytopathological changes in exfoliated urothelial cells from individuals previously exposed to benzidine in Shanghai. This contradicts the results of studies indicating that the GSTM1 0/0 genotype is associated with an increased risk for bladder cancer in the general population, mostly outside China.

Oxidative stress contributes to hepatitis C virus (HCV)-induced liver damage. Host genetic factors may be involved in progression of HCV infection. The present study was conducted to determine the influence of glutathione S-transferase (GST)-M1 and T1 gene polymorphisms during different stages of HCV infection, including chronic hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). The study population comprised 190 patients (47 with chronic hepatitis, 83 with cirrhosis (without HCC), and 60 with HCC). GSTM1 and GSTT1 gene polymorphisms were analyzed via multiplex polymerase chain reaction. The GSTT1-null genotype was more commonly detected in patients with cirrhosis (n = 17; 20.5%) and HCC (n = 13; 21.7%) than those with chronic hepatitis (n = 3; 6.4%). The differences in GSTT1-null genotype frequencies were significant for cirrhosis vs. chronic hepatitis (odds ratio, OR, 3.778 (95% confidence interval, CI, 1.045-13.659); p = 0.043) and HCC vs. chronic hepatitis (OR, 4.057 (95% CI, 1.083-15.201); p = 0.038) groups. However, the incidence of individual GSTM1-null or combined GSTM1/GSTT1 double-null genotypes did not vary significantly between the groups. Our collective findings support the utility of the GSTT1-null genotype as a useful biomarker for liver disease progression in Brazilian patients with chronic hepatitis C.

Keywords: cirrhosis; glutathione S-transferases; hepatitis C virus; hepatocellular carcinoma; polymorphisms.

In the inductive phase of contact allergic dermatitis, simple chemical compounds (haptens) produce together with epidermic proteins adducts presented by Langerhans cells to T lymphocytes. Binding to protein carrier is a necessary condition of transforming a low-molecular allergen into immunogenic one and evoking immunological reaction. The production of allergen adducts with proteins is conditioned by the presence of electrophilic groups in their molecules, or their acquiring during biotransformation phase I. Active allergen metabolites undergo further alterations during biotransformation phase II which leads most frequently to the decline in their chemical activity and more rapid excretion from the body. The number of reactive metabolites (reactive allergens) available for producing adducts with proteins keeps the balance between activation and deactivation reactions. Glutathione S-transferases play a particular role in the allergens (or their metabolites) deactivation process in biotransformation phase II. These enzymes catalyse reactions responsible for the declined electrophilic potential of allergens (or their metabolites), and thus for the decrease in the number of allergen molecules able to produce protein covalent bindings (adducts). Glutathione S-transferases, occurring in the human cellular cytoplasm belong to five classes: alpha(GST A), mu(GST M), theta(GST P), pi(GST T) and Z(GST Z), as well as to one class present in microsomes. The study indicated the presence of isoenzymes GST T1 and GST M1 in the skin. Both isoforms participate in the process of low-molecular allergen biotransformation. Carriers of defective genes GST T1 and/or GST M1 are more vulnerable to allergenic effect of some allergens, e.g. thimerosal, which is associated with the absence of or decrease in the activity of isoenzymes GST T1 and GST M1.

Selective protein recognition is critical in molecular biology techniques such as Western blotting and ELISA. Successful detection of the target proteins in these methods relies on the specific interaction of the antibodies, which often bring a high production cost and require a long incubation time. Aptamers represent an alternative class of simple and affordable affinity reagents for protein recognition, and replacing antibodies with aptamers in Western blotting would potentially be more time- and cost-effective. In this work, multiple fluorescent DNA aptamers were isolated by in vitro selection to selectively label commonly used tag proteins including GST, MBP, and His-tag. The generated aptamers G1, M1, and H1 specifically bound to their cognate target proteins with nanomolar affinities, respectively. Compared with conventional antibody-based immunoblotting, such aptamer-based procedure gave a cleaner background and was able to selectively label target protein in a complex mixture. Lastly, the identified aptamers were also effective in recognition of different fusion proteins with the same tag, thus greatly expanding the scope of the potential applications of these aptamers. This work provided aptamers as useful molecular tools for selective protein recognition in Western blotting analysis.

Keywords: Western blot; aptamer; functional nucleic acid; in vitro selection; protein recognition.

The frequency of the null allele phenotype of glutathione S-transferase (GST) M1 was investigated in 114 Zimbabweans and results for a subset of 63 subjects were compared with genotyping by PCR. In addition, the effect of the antimalarial chloroquine on blood levels of GSTM1 and GSTA in 19 subjects was studied. Quantification of GSTs was by enzyme linked immunosorbent assays (ELISA). Thirty percent of the subjects were of the GSTM1 null phenotype. Comparison of results of phenotyping by ELISA and genotyping by PCR showed that 16% of samples were in discordance; unknown mutations in the GSTM1 gene in the Zimbabwean population may explain this observation. Chloroquine decreased levels of blood GSTM1 and GSTA by 50% or more. In populations treated with chloroquine, these decreases in GST activities might lead to compromised ability to detoxify xenobiotics, could confound GSTM1 phenotyping and might invalidate use of GSTA as an indicator of liver damage.

Clozapine, an often-prescribed antipsychotic drug, is implicated in severe adverse drug reactions (ADRs). Formation of reactive intermediates by cytochrome P450s (CYPs) has been proposed as a possible explanation for these ADRs. Moreover, a protective role for human glutathione S-transferases (hGSTs) was recently shown using purified enzymes. We investigated the interplay between CYP bioactivation and GST detoxification in a reconstituted cellular context using recombinant yeast expressing a bacterial CYP BM3 mutant (M1GSTA1-1, M1-1 or P1-1. Clozapine and the N-desmethylclozapine metabolite caused comparable growth inhibition and reactive oxygen species (ROS) formation, whereas the clozapine-N-oxide metabolite was clearly less toxic. Clozapine metabolism by BM3 M1GSTs in yeast was confirmed by identification of stable clozapine metabolites and hGST isoform-specific glutathione-conjugates. Oxidative metabolism of clozapine by BM3 M1GSTP1-1 protected yeast from BM3 M1GSTA1-1 and hGSTM1-1 did not. ROS formation was not lowered by hGSTP1-1 co-expression and was unrelated to mitochondrial electron transport chain (mETC) activity. We present a novel cellular model to study the effect of CYP and GST interplay in drug toxicity.

The progress of various symptoms in adjuvant arthritic rats (AA-rats) and the effects of anti-rheumatic drugs were continuously observed on the basis of the Weibull distribution function, and the following results were obtained: 1) The cumulative incidence rates F(t) of various symptoms and abnormalities of measured values gradually increased with the passage of time. The relationship between the F(t) and the days after adjuvant injection indicated a simple Weibull distribution function. On the other hand, the bone damages in the distal limb joints indicated a composite Weibull distribution function with two shape parameters (m1 and m2). It was possible to classify the animals into two groups, fast responders (m1) and slow responders (m2), according to the time of occurrence of bone damages. 2) By using the Weibull probability paper, it was possible to integrate and to evaluate in totality those cases with varying grades of symptoms and cases with different symptoms in the adjuvant-induced syndrome in rats. 3) Azathioprine (AZP) showed an inhibitory effect on the advents of pain and swelling and functional disorders, while indomethacin (IDM), prednisolone (PSL) and gold sodium thiomalate (GST) delayed the advents of these symptoms. As to bone damages in the distal limb joints, IDM, PSL and AZP showed an inhibitory effect in only the fast responder group, while GST showed both an inhibitory and delaying effect in both the fast responder group and the slow one. The above results suggest that the usage of the Weibull distribution function is useful not only for analysis of the morbid condition of AA-rats but also for the evaluation of anti-rheumatic drugs in AA-rats.

Background: Head and Neck Cancer (HNC) survivors are at increased risk of developing a second primary cancer (SPC). Along with the environmental risk factors, genetic factors have been associated with a potential increased susceptibility to SPC development. We aim to identify the Single Nucleotide Polymorphisms (SNPs) that contribute to SPC development among HNC survivors through a systematic review and meta-analysis.

Methods: We searched PubMed, Scopus and ISI Web of Science for eligible studies published in English until January 31st, 2020. We included studies reporting primary data that evaluated the association between SNPs and SPC risk in HNC patients. Data were pooled in a random-effect meta-analyses, when at least two studies on the same SNP evaluated the same genotype model. Heterogeneity was assessed using the χ2-based Q-statistics and the I² statistics. Quality of the included studies was assessed using the Q-Genie tool.

Results: Twenty-one studies, of moderate to good quality, were included in the systematic review. Fifty-one genes were reported across the included studies to have significant associations with an increased SPC risk. Overall, 81 out of 122 investigated SNPs were significantly associated with the SPC risk. Seven studies were included in the meta-analysis, which showed five SNPs associated with an increased risk of SPC: p21C70T, CT + TT (HR = 1.76; 95% CI: 1.28-2.43); FASLG -844C > T, CT + TT (HR = 1.82; 95% CI: 1.35-2.46), P21 C98A, CA + AA (HR = 1.75; 95% CI: 1.28-2.38); FAS -670A > G (HR = 1.84; 95% CI: 1.28-2.66) and GST-M1, Null genotype (HR = 1.54; 95% CI: 1.13-2.10).

Conclusions: The identified SNPs in our systematic review and meta-analysis might serve as potential markers for identification of patients at high risk of developing SPC after primary HNC.

Prospero registration number: CRD42019135612 .

Keywords: Biomarker; Head and neck cancer; Personalized medicine; Second primary cancer; Single nucleotide polymorphism.

Background: Gestational diabetes mellitus (GDM) shares in part pathogenic mechanisms of multiple genetic interactions. Some ofT2D susceptibility genes are encountered in association with GDM.

Objective: We aimed to investigate for GST T1, M1 and G972R IRS-I gene polymorphisms with the risk of developing GDM.

Patients and methods: In this randomized case-control study, pregnant women with GDM were genotyped for by PCR analysis for glutathione s-transferase-T1, M1 variant polymorphisms. RFLP was done for the G972R IRS 1 gene. Their newborns were additionally assayed for whole of the clinical, laboratory and genetic aspects.

Results: The T allele, IRS-1rs1801278 TT genotype were frequently detected in GDM mothers in comparison to healthy control ones [for TT homozygous variant; OR(CI 95%): 2.05(1.09-3.87, p: 0.025].Furthermore, GST T1 null was significantly presented in GDM mothers than those of control mother [OR (CI95%: 0.29 (0.084-1.02), p:0.04].Added to the significant correlation of glycemic indices to clinical parameters of infants born to GDM, M1-null genotype of GST was significantly correlated (p<0.05) to abnormal values of respiratory rates and 1 minute-APGAR scores noted for extra NICU care.

Conclusion: Our results suggested GST T1null and IRS-1 TT genotypic variants were claimed for GDM development among Egyptian women with possible impact on their newly born infants.

Keywords: GST T; Gestational diabetes mellitus; IRS-1.; M1; maternal hyperglycemia; neonate.

1. Glutathione S-transferases (<em>GST</em>) and cytochrome P450s (CYPs) are xenobiotic metabolizing enzymes participating in the protection of cell. The present study aimed to investigate the relationship between polymorphisms of glutathione S-transferase <em>M1</em> (<i><em>GST</em><em>M1</em></i>) null, glutathione S-transferase T1 (<i><em>GST</em>T1</i>) null, glutathione S-transferase P1 (<i><em>GST</em>P1</i>) Ile105Val, cytochrome P450 1A2 (<i>CYP1A2</i>) 734 C→A, cytochrome P450 2D6 (<i>CYP2D6</i>) <i>1934 G→A</i> and male infertility. 2. A total of 306 azoospermic or oligozoospermic infertile men and 129 normozoospermic or fertile controls were enrolled in the study. Multiplex polymerase chain reaction (PCR) or PCR-restriction fragment length polymorphism methods were used for genotyping. There was a significant relationship between male infertility and <i>CYP2D6 GG</i> genotype (<i>p</i> < 0.001). <i>CYP1A2</i> AA genotype was slightly higher in the infertile group <i>(p</i> = 0.056). 3. There was no association between <i><em>GST</em>T1</i> null polymorphisms and male infertility (<i>p</i> = 0.068), <i><em>GST</em><em>M1</em></i> null <i>(p</i> = 0.843) and <i><em>GST</em>P1</i> Ile105Val (<i>p</i> = 0.192) genes. <i><em>GST</em><em>M1</em></i> null genotype frequency was higher in azoospermic men <i>(p</i> = 0.009). Men carrying <i>CYP1A2</i> AA genotype had higher risk of infertility risk (OR = 3.14; %95 CI = 1.16-8.54) in the smoker group. 4. Our results demonstrated that polymorphisms of <i>CYP2D6</i> and <i>CYP1A2</i> may play a role in idiopathic male infertility in our sample population.

Fumaric acid esters (FAE) are beneficial in the treatment of psoriasis. However, about a third of psoriasis patients do not respond to FAE. We aimed to determine whether glutathione-S-transferase (GST) M1 and GSTP1 polymorphisms are associated with treatment outcome in psoriasis patients treated with FAE. We studied 84 psoriasis patients who were treated with FAE for 3 months. FAE nonresponders were defined as having psoriasis area and severity improvement index less than 50% after 3-month therapy. GSTM1 genotyping for gene deletion and GSTP1 exon 5 105 Ile→Val polymorphisms were assessed using a high-resolution melting analysis. A dropout rate of 23.8% (20/84) was found; 25% (16/64) were FAE nonresponders. We observed 42 (84/50%) patients with G 9STM1*0 homozygous alleles and 42 (84/50%) patients with one or two active GSTM1 alleles. The Ile/Ile GSTP1 genotype was observed in 37 (84/44%), the Ile/Val GSTP1 genotype in 38 (84/45.2%) patients and the Val/Val GSTP1 genotype in nine (84/10.7%) patients. There was no significant (P>0.05) association between the GST genotypes assessed and the frequency FAE responder status, except for the Val/Val GSTP1 polymorphism, which was a significant (overall model fit; P=0.0012) predictor for nonresponders with an odds ratio of 43.4 (95% confidence interval: 4.2-511.1). The coefficient of regression was 3.9, with a SE of 1.2 as assessed by logistic regression analysis (P=0.0017). The Val/Val GSTP1 polymorphism predicts nonresponders in FAE treatment of psoriasis patients and may therefore serve as a biomarker that enables a laboratory-based pretreatment selection of patients.

Acquired sensorineural hearing loss (SNHL), including age-related hearing loss (ARHL), noise-induced hearing loss (NIHL), drug-induced hearing loss (DIHL) and sudden sensorineural hearing loss (SSHL), is one of the most common sensory deficits in humans. Several studies have reported that antioxidant gene glutathione s-transferase M1 and T1 (GST M1 and T1) polymorphisms have a close relationship with the susceptibility to acquired SNHL, but other articles have reported opposite results. This meta-analysis aims to identify whether an association exists between GST M1 and T1 polymorphisms and the susceptibility to acquired SNHL. Seventeen independent studies containing 1749 cases and 2018 controls were included. According to the I² value of the heterogeneity test, random-effects model was selected to calculate the pooled odds ratios (ORs) with their 95% confidence intervals (95% CIs) and p values. The pooled ORs (95% CI, p-value) of GST M1 and T1 were 1.186(0.955-1.473, p = 0.122) and 1.107(0.841-1.458, p = 1.467), respectively. In addition, subgroup analyses according to the type of SNHL and ethnicity showed no relationship between GST M1 and T1 polymorphisms and the susceptibility to acquired SNHL. Our results suggest that no significant relationship was found between GST M1 and T1 polymorphisms and the susceptibility to acquired SNHL.

Cytosolic glutathione S-transferase (GST) enzymes participate in several cellular processes in addition to facilitating glutathione conjugation reactions that eliminate endogenous and exogenous toxic compounds, especially electrophiles. GSTs are thought to interact with various kinases, resulting in the modulation of apoptotic processes and cellular proliferation. The present research used a combination of in silico and in vitro studies to investigate protein-protein interactions between the seven most abundant cytosolic GSTs-GST alpha-1 (GST-A1), GST alpha-2 (GST-A2), GST mu-1 (GST-M1), GST mu-2 (GST-M2), GST mu-5 (GST-M5), GST theta-1 (GST-T1) and GST pi-1 (GST-P1)-and Mitogen-activated protein kinase 8 (MAPK8) and Apoptosis signal-regulating kinase 1 (ASK1). MAPK8 and ASK1 were chosen as this study's protein interaction partners because of their predominant role in electrophile or cytokine-induced stress-mediated apoptosis, inflammation and fibrosis. The highest degree of sequence homology or sequence similarity was observed in two GST subgroups: the GST-A1, GST-A2 and GST-P1 isoforms constituted subgroup1; the GST-M1, GST-M2 and GST-M5 isoforms constituted subgroup 2. The GST-T1 isoform diverged from these isoforms. In silico investigations revealed that GST-M1 showed a significantly higher binding affinity to MAPK8, and its complex was more structurally stable than the other isoforms, in the order GST-M1 > GST-M5 > GST-P1 > GST-A2 > GST-A1 > GST-M2 > GST-T1. Similarly, GST-A1, GST-P1 and GST-T1 actively interacted with ASK1, and their structural stability was also better, in the order GST-T1 > GST-A1 > GST-P1 > GST-A2 > GST-M5 > GST-M1 > GST-M2. To validate in silico results, we performed in vitro crosslinking and mass spectroscopy experiments. Results indicated that GST-M1 interacted with GST-T1 to form heterodimers and confirmed the predicted interaction between GST-M1 and MAPK8. Communicated by Ramaswamy H. Sarma.

Keywords: ASK1; GST-M1; GST-T1; MAPK8; MD simulations; protein–protein docking.

Glutathione-S transferases (GSTs) are xenobiotic-conjugation enzymes involved in the detoxification process of heterocyclic aromatic amines and polycyclic aromatic hydrocarbons, widely recognized risk factors of colorectal cancer (CRC) development. Polymorphism in GSTs often leads to alteration or complete lack of enzyme activity, which might have an effect on CRC carcinogenesis. Aim of this study was to investigate GST gene variants as risk factors in patients with CRC. A total of 523 CRC patients administered for surgical resection and 400 matched controls were included. Deletion polymorphism of GSTs M1 and T1 was investigated by polymerase chain reaction. Single nucleotide polymorphism of GST A1 and P1 was investigated by restriction fragment length polymorphism method. The association between GST genotype and risk of CRC development was found in carriers of GSTT1-null and GSTP1-variant genotypes individually (p = 0.050 and p = 0.016, respectively). Furthermore, statistically significant association was found when combination of GSTP1-variant genotype with any of other three common GST genotypes was analyzed with respect to CRC susceptibility. Additionally, patients with combined GSTM1-null/GSTT1-null/GSTA1 low-activity/GSTP1-variant genotype showed 2.71-fold increased risk of developing CRC (p = 0.037). This study supports hypothesis that GST polymorphisms might have an important role in the process of the CRC development. Additionally, GSTM1-null/ GSTT1-null/ GSTA1 low-activity/ GSTP1-variant genotype could be combination of GST genotypes whose carriers are more prone to CRC development.

Glutathione S-transferases (GST) play an important role in oxidative stress related syndromes. An imbalance of the oxidant and antioxidant systems is important in the pathogenesis of Behcet's disease (BD). The objective of this study was to evaluate the association of null genotypes of GST-M1 and GST-T1 with BD since some preliminary molecular genetic data were recently published. Ninety-four Turkish BD patients (42 male, 52 female, 37.1+/-10.4 years) and 140 healthy volunteers (70 male, 70 female, 36.8+/-11.7 years) matched for age and gender with the patients as the control group were included in the study. Distributions of GST-M1 and GST-T1 genotypes were determined by multiplexed PCR using three sets of primers for GST-M1, GST-T1, and beta-globulin genes. There was no association between BD and the frequencies of GST-M1 and GST-T1 null genotypes when compared to controls by separate analysis. However, by cross and pooled combination analysis there was a significant association between the frequencies of pooled GSTs with one or both null genotypes in BD and controls. This is the first evidence that the association between the frequencies of GST-M1 and GST-T1 null genotypes and BD might be dependent on the interaction of multiple null allele polymorphisms rather than a single null allele of GST-M1 and GST-T1.

OBJECTIVE

To study the relationship between glutathione S transferase M1(GST mu) gene deletion and leukemia in workers exposed to benzene.

METHODS

A matched population-based case-control survey with multivariate Logistic regression analysis was conducted in this study.

RESULTS

In the population of 34 patients and their matched controls, the absence of the GST mu genotype conferred odds ratio of 3.6. It suggested that GST mu was an important determinant of heterogeneity in individual susceptibility to leukemia associated with exposure to benzene. The single-variance analysis indicated that these markedly significant factors were GST mu gene deletion, GST mu isoenzyme activity, duration of exposure, GST isoenzyme activity, smoking quantity and average concentration of benzene in workshop air. The multivariate analysis indicated that these markedly significant factors were GST mu gene deletion, duration of exposure to benzene and GST mu isoenzyme activity.

CONCLUSIONS

GST mu gene deletion may be associated with increased risk of leukemia in workers exposed to benzene and is one of genetically determined factors.

Glutathione S-transferase (GST) M1 polymorphism is a marker for susceptibility to smoking-related neoplasms, such as lung and bladder cancer. Recently, a genetic deletion of GSTT1, an isoenzyme of GST, has been reported to be associated with myelodysplastic syndromes (MDS). A 59-year-old man with a long-term smoking habit was treated successfully for non-small-cell lung cancer. Four years after the surgical removal of his lung cancer, he developed MDS and died. Using a polymerase chain reaction-based genotyping method, he was found to have a deletion of both the GSTM1 and GSTT1 genes. Screening for the deletion of the GSTM1 and GSTT1 genes may be useful for assessing individual genetic susceptibility to smoking-related lung cancer and MDS.

Epidemiological evidence on the association between genetic polymorphisms in glutathione S-transferases M1 (GSTM1) and T1 (GSTT1) genes and risk of endometrial cancer (EC) has been inconsistent. In this meta-analysis, we seek to investigate the relationship between GSTM1 and GSTT1 polymorphisms and the risk of EC. We searched Medline, PubMed, Web of Science, Embase, Chinese National Knowledge Infrastructure database, and Chinese Biomedical Literature database to identify eligible studies. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) for the association were determined using a fixed- or random-effect model. Tests for heterogeneity of the results and sensitivity analyses were performed. A total of six case-control studies were included in the final meta-analysis of GSTM1 (1293 cases and 2211 controls) and GSTT1 (1286 cases and 2200 controls) genotypes. Overall, GSTM1 null genotype was not significantly associated with an increased risk of EC (OR = 1.00, 95% CI = 0.76-1.30, P = 0.982). Similarly, for GSTT1 deletion genotype, we observed no association under the investigated model in the overall analysis (OR = 0.91, 95% CI = 0.64-1.30, P = 0.619). Subgroup analysis also showed no significant association between the GSTM1 null genotype and EC risk in hospital-based design (OR = 1.26, 95% CI = 0.93-1.71, P = 0.131) and no relationship between GSTT1 null genotype with EC risk in population-based design (OR = 1.18, 95% CI = 0.79-1.76, P = 0.407). However, GSTM1 null genotype contributed to an increased EC risk in population-based design (OR = 0.76, 95% CI = 0.60-0.97, P = 0.027), while null GSTT1 in hospital-based studies (OR = 0.70, 95% CI = 0.52-0.93, P = 0.015). The present meta-analysis suggested that GSTs genetic polymorphisms may not be involved in the etiology of EC. Large epidemiological studies with the combination of GSTM1 null, GSTT1 null, and design-specific with the development of EC are needed to prove our findings.

This study aimed to investigate the association between glutathione S-transferase (GST) M1 and T1 null genotypes and thiobarbituric acid reactive substances (TBARS), total antioxidant capacity (TAC) and nitric oxide (NO) levels in male infertility. For this purpose, semen samples were collected from fertile and infertile subjects, and then they were genotyped for GSTT1 and GSTM1 genes using multiplex-PCR. The TBARS, TAC and NO levels in seminal plasma were then measured via the ferric-reducing ability of plasma (FRAP). A significant association was observed between GSTT1 null genotype and oligozoospermia, asthenozoospermia and teratozoospermia. But, the GSTM1 null genotype was merely associated with teratozoospermia. Moreover, the GSTT1-/GSTM1+ combined genotype was associated with all subgroups of male infertility. Besides, an association was observed between GSTT1-/GSTM1- genotype and asthenozoospermia and teratozoospermia. Further analysis showed that the GSTT1 null genotype was associated with increased NO in asthenozoospermia. Also, the GSTT1 null genotype was associated with increased TBARS in oligozoospermia and asthenozoospermia. As well, GSTM1 null genotype was associated with decreased TAC and increased NO in asthenozoospermia respectively. As a preliminary conclusion, the GSTM1 and GSTT1 null genotypes could be considered as genetic risk factors for male infertility, interfering with some oxidative stress markers in infertile men.

Keywords: genetic polymorphism; glutathione S-transferases; male infertility; oxidative stress marker.

The active-site (the H-site) hydrophobicity of five human glutathione S-transferases (GSTs) was analyzed by application of linear free energy relationships (LFERs) with a series of S-alkylated glutathione inhibitors, GS(CH2)n - 1CH3 (n = 1-14). Distinct linear reltionships were observed in the plots of log Ki (inhibition constant) vs n for the five forms, whereby the Kis varied by three to four orders of magnitude. Mean free enthalpy changes per methylene group (-Delta DeltaG degreess), a measure of H-site hydrophobicity, were in the order M1-1 (4.6 kJ/mol)>> A1-1 (3. 9 kJ/mol)>> A1-2 (3.8 kJ/mol)>> A2-2 (2.8 kJ/mol)>> P1-1 (1.6 kJ/mol). The quantitative differences may in part account for the extraordinary broad and overlapping substrate specificities of the Alpha-, Mu-, and Pi-class isoenzymes. In contrast to the Alpha and Mu classes being selective for strongly electrophilic compounds, the neoplastic P1-1 species was indicated to be selective for weakly electrophilic and water-soluble carcinogens such as acrolein and hydroxyalkenals.

OBJECTIVE

An association between endometriosis and the glutathione S-transferase M1 (GSTM1)- and GSTT1-related genes has been proposed on account of the detoxification properties of the GST enzymes. The aim of the present study was to investigate whether the polymorphisms and null mutations are associated with the susceptibility to endometriosis.

METHODS

The study included 105 women with endometriosis and 150 healthy women with no laparoscopic evidence of disease. Genotyping of the GSTM1 and GSTT1 gene polymorphisms was performed by Multiplex-PCR.

RESULTS

There was a significant association of GSTM1 null and GSTT1 null genotypes with endometriosis both when studied alone (P = 0.001 and P = 0.03, respectively) and in combination (P = 0.00002).

CONCLUSIONS

The findings suggest that the GSTM1 and GSTT1 gene deficiency predisposes to endometriosis in a Tunisian population and can confer a significant increased risk when the GST null genotypes are combined.

Glutathione S-transferases (GSTs) are a family of enzymes which are involved in the detoxification of potential carcinogens. Glutathione S-transferase M1 (GSTM1) null genotype can impair the enzyme activity of GSTs and is suspected to increase the susceptibility to gallbladder cancer. Previous studies investigating the association between GSTM1 null genotype and risk of gallbladder cancer reported inconsistent findings. To quantify the association between GSTM1 null genotype and risk of gallbladder cancer, we performed a meta-analysis of published studies. We searched PubMed, Embase, and Wanfang databases for all possible studies. We estimated the pooled odds ratio (OR) with its 95% confidence interval (95% CI) to assess the association. Meta-analysis of total included studies showed that GSTM1 null genotype was not associated with gallbladder cancer risk (OR = 1.13, 95% CI 0.88-1.46, P = 0.332). Subgroup analysis by ethnicity showed that there was no association between GSTM1 null genotype and risk of gallbladder cancer in both Caucasians and Asians. However, meta-analysis of studies with adjusted estimations showed that GSTM1 null genotype was associated with increased risk of gallbladder cancer (OR = 1.46, 95% CI 1.02-2.09, P = 0.038). Thus, this meta-analysis shows that GSTM1 null genotype is likely to be associated with risk of gallbladder cancer. More studies with well design and large sample size are needed to further validate the association between GSTM1 null genotype and gallbladder cancer.