Glutathione S-transferase polymorphisms (GSTM1, GSTT1 and GSTP1) and their susceptibility to renal cell carcinoma: an evidence-based meta-analysis

Role of GSTM1 in Hypertension, CKD, and Related Diseases across the Life Span

Over 20 years after the introduction of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, CKD remains a major public health burden with limited therapeutic options to halt or slow kidney disease progression at all ages. The consensus is that oxidative stress contributes to CKD development and progression. Yet, to date, there is no clear evidence that broad use of antioxidant therapy provides a beneficial effect in CKD. Understanding the specific pathophysiologic mechanisms in those who are genetically most susceptible to oxidative stress is a crucial step to inform therapy in an individualized medicine approach, considering differing exposures and risks across the life span. Glutathione-S-transferase μ 1 (GSTM1) is a phase 2 enzyme involved in inactivation of reactive oxygen species and metabolism of xenobiotics. In particular, those with the highly prevalent GSTM1 null genotype (GSTM1[0/0]) may be more susceptible to kidney disease progression, due to impaired capacity to handle the increased oxidative stress burden in disease states, and might specifically benefit from therapy that targets the redox imbalance mediated by loss of the GSTM1 enzyme. In this review, we will discuss the studies implicating the role of GSTM1 deficiency in kidney and related diseases from experimental rodent models to humans, from the prenatal period through senescence, and the potential underlying mechanism.

The Association of Polymorphisms in Nrf2 and Genes Involved in Redox Homeostasis in the Development and Progression of Clear Cell Renal Cell Carcinoma

Deleterious effects of SNPs found in genes encoding transcriptional factors, as well as antioxidant and detoxification enzymes, are disputable; however, their functional significance seems to modify the risk for clear cell renal cell carcinoma (ccRCC) development and progression. We investigated the effect of specific Nrf2, SOD2, GPX1 gene variants and GSTP1ABCD haplotype on ccRCC risk and prognosis and evaluated the association between GSTP1 and regulatory (JNK1/2) and executor (caspase-3) apoptotic molecule expression in ccRCC tissue samples and the presence of GSTP1 : JNK1/2 protein : protein interactions. Genotyping was performed in 223 ccRCC patients and 336 matched controls by PCR-CTTP and qPCR. Protein expression was analyzed using immunoblot, while the existence of GSTP1 : JNK1 protein : protein interactions was investigated by immunoprecipitation experiments. An increased risk of ccRCC development was found among carriers of variant genotypes of both SOD2 rs4880 and GSTP1 rs1695 polymorphisms. Nrf2 rs6721961 genetic polymorphism in combination with both rs4880 and rs1695 showed higher ccRCC risk as well. Haplotype analysis revealed significant risk of ccRCC development in carriers of the GSTP1C haplotype. Furthermore, GSTP1 variant forms seem to affect the overall survival in ccRCC patients, and the proposed molecular mechanism underlying the GSTP1 prognostic role might be the presence of GSTP1 : JNK1/2 protein : protein interactions.

Glutathione transferase genotypes may serve as determinants of risk and prognosis in renal cell carcinoma

Renal cell carcinoma (RCC) represents a group of histologically similar neoplasms with significant intratumor and intertumor genetic heterogeneity. Recognized risk factors for RCC development include smoking, hypertension, obesity, as well as von Hippel-Lindau (VHL) disease. Inactivation of VHL, deregulated nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway, and altered redox homeostasis, together with changes in glutathione transferase (GST) profile, are considered as important contributing factors in RCC development and progression. Although the available results of both gene-gene and gene-environment analysis are quite heterogeneous, they clearly indicate that certain GST genotypes may play a role as risk modifiers, either individually or in combination with other Phase I or Phase II gene polymorphisms, as well as in subjects exposed to relevant substrates. Seemingly, GST genotyping could identify individuals with impaired detoxification in renal parenchyma that are at higher risk of developing RCC. In addition to well established roles of GSTs in conjugation and biotransformation of xenobiotics, GSTs have emerged as significant regulators of pathways determining cell proliferation and survival. Indeed, there are evidence in favor of GST significance, not only in terms of risk for RCC development, but also with respect to progression and prognosis. So far, GSTM1-active genotype was confirmed to be an independent predictor of higher risk of overall mortality. Therefore, it is reasonable to assume that certain GST variants may assist in individual RCC risk assessment, as well as postoperative prognosis. Even more, GST profiling might contribute to development of personalized targeted therapy in RCC patients.

A systematic review and meta-analyses of the relationship between glutathione S-transferase gene polymorphisms and renal cell carcinoma susceptibility

BACKGROUND

Association of GSTM1- and GSTT1-null genotypes, GSTP1 A/G gene polymorphism with renal cell carcinoma (RCC) susceptibility was detected, and the relationship between the GSTM1/GSTT1-null genotype and clinical TNM stages of RCC was assessed, using meta-analysis method.

METHODS

Association investigations according to eligibility criteria were searched and identified from the databases of Cochrane Library, PubMed, and Embase from establishment time of databases to July 1, 2017, and eligible reports were analyzed by meta-analysis. 95% confidence intervals (CI) were also detected, and odds ratios (OR) was used to express the results for dichotomous data.

RESULTS

This meta-analysis indicated that there was no an association between GSTM1-null genotype, GSTT1-null genotype, GSTP1 A/G gene polymorphism and RCC risk in the overall population of Caucasians or Asians. The dual GSTM1-GSTT1-null genotype was also not associated with RCC in the overall population of Caucasians. Interestingly, there was an association between the dual GSTM1-GSTT1-null genotype and the susceptibility of RCC in Asians. Relationship of the GSTM1-null genotype with clinical TNM stage of RCC was not observed in the overall population of Asians or Caucasians. In this meta-analysis, no association between the GSTT1-null genotype and clinical TNM stage of RCC was observed in Caucasians or Asians. Interestingly, GSTT1-null genotype was detected to be associated with the clinical TNM stages in patients with RCC in the overall population.

CONCLUSION

The dual GSTM1-GSTT1-null genotype is detected to be associated with the onset of RCC in Asians, and there is an association between the GSTT1-null genotype and the clinical TNM stages in patients with RCC in the overall population.

Association of the -344T/C polymorphism in aldosterone synthase gene promoter with left ventricular structure in Chinese Han: A meta-analysis

No consensus view has been published on the relationship between the aldosterone synthase gene (CYP11B2) -344C/T polymorphism and left ventricular hypertrophy (LVH) in Chinese Han. We undertook a meta-analysis to investigate the potential association of this polymorphism and left ventricular structure-related phenotypes, including left ventricular mass (LVM), left ventricular mass index (LVMI), left ventricular end systolic diameter (LVESD), left ventricular end diastolic dimension (LVEDD), left ventricular posterior wall thickness (LVPWT), and interventricular septal wall thickness (IVS). Studies in English and Chinese were found based on a systematic search of Medline, Embase, CNKI, and Wanfang databases. The dominant model (TT vs. TC+CC) and homozygote model (TT vs. CC) were selected to examine the association between the -344C/T polymorphism and LVH. The random-effects model was used to pool data. From a total of 3104 participants, despite the investigation of six echocardiographic indicators, we found no significant association between the -344C/T variant and LVH in the whole group and the subgroup analyses by blood pressure. However, in the subgroup of northern Han Chinese, TT genotype had higher LVPWT than CC genotype and TC genotype (p_{heterogeneity} = 0.4, p_value = 0.04, 95% CI 0.09 (0.00, 0.18)). In addition, no evidence of publication bias was observed. In conclusion, our meta-analysis indicated that subjects with TT genotype might have higher risk of developing LVH in northern Han Chinese.

Genetic susceptibility in Juvenile Myoclonic Epilepsy: Systematic review of genetic association studies

BACKGROUND

Several genetic association investigations have been performed over the last three decades to identify variants underlying Juvenile Myoclonic Epilepsy (JME). Here, we evaluate the accumulating findings and provide an updated perspective of these studies.

METHODOLOGY

A systematic literature search was conducted using the PubMed, Embase, Scopus, Lilacs, epiGAD, Google Scholar and Sigle up to February 12, 2016. The quality of the included studies was assessed by a score and classified as low and high quality. Beyond outcome measures, information was extracted on the setting for each study, characteristics of population samples and polymorphisms.

RESULTS

Fifty studies met eligibility criteria and were used for data extraction. With a single exception, all studies used a candidate gene approach, providing data on 229 polymorphisms in or near 55 different genes. Of variants investigating in independent data sets, only rs2029461 SNP in GRM4, rs3743123 in CX36 and rs3918149 in BRD2 showed a significant association with JME in at least two different background populations. The lack of consistent associations might be due to variations in experimental design and/or limitations of the approach.

CONCLUSIONS

Thus, despite intense research evidence established, specific genetic variants in JME susceptibility remain inconclusive. We discussed several issues that may compromise the quality of the results, including methodological bias, endophenotype and potential involvement of epigenetic factors.

PROSPERO REGISTRATION NUMBER

CRD42016036063.

GSTM1 genotype is an independent prognostic factor in clear cell renal cell carcinoma

PURPOSE

Owing to dual functionality of cytosolic glutathione S-transferases (GSTs), they might affect both the development and the progression of renal cell carcinoma (RCC). However, the data on the prognostic value of GST polymorphism in patients with RCC are scarce. Hence, we evaluated the effect of GST gene variants on both the risk of RCC development and the postoperative prognosis in patients with clear cell RCC (ccRCC).

METHODS

GST genotypes were determined in 305 patients with RCC and 326 matched controls, whereas the overall survival was evaluated in patients with ccRCC only. The presence of GSTM1:ASK1 protein-protein interaction in ccRCC tissue samples was analyzed by methods of immunoprecipitation and immunoblot.

RESULTS

We noted an increased risk of RCC development in carriers of GSTM1-null and GSTP1-variant genotype (P<0.05). On the contrary, survival analysis indicated shorter overall survival for patients with ccRCC with GSTM1-active genotype (P = 0.026). Furthermore, patients with ccRCC with GSTM1-active genotype had significantly higher hazard ratio (P<0.05), in analyzed regression models, compared with the carriers of GSTM1-null genotype. Finally, the presence of GSTM1:ASK1 protein-protein interaction was found in all RCC tissue samples studied.

CONCLUSIONS

Carriers of GSTM1-null and GSTP1-variant genotypes are in increased risk of RCC development. On the contrary, GSTM1-null genotype is associated with favorable postoperative prognosis in ccRCC. The possible molecular mechanism underlying the role of GSTM1 protein in RCC progression might be the presence of GSTM1:ASK1 protein-protein interaction. Hence, determination of GSTM1-genotype might serve as a valuable indicator in both RCC risk assessment and postoperative prognosis.

Combined GSTM1-Null, GSTT1-Active, GSTA1 Low-Activity and GSTP1-Variant Genotype Is Associated with Increased Risk of Clear Cell Renal Cell Carcinoma

The aim of this study was to evaluate specific glutathione S-transferase (GST) gene variants as determinants of risk in patients with clear cell renal cell carcinoma (cRCC), independently or simultaneously with established RCC risk factors, as well as to discern whether phenotype changes reflect genotype-associated risk. GSTA1, GSTM1, GSTP1 and GSTT1 genotypes were determined in 199 cRCC patients and 274 matched controls. Benzo(a)pyrene diolepoxide (BPDE)-DNA adducts were determined in DNA samples obtained from cRCC patients by ELISA method. Significant association between GST genotype and risk of cRCC development was found for the GSTM1-null and GSTP1-variant genotype (p = 0.02 and p<0.001, respectively). Furthermore, 22% of all recruited cRCC patients were carriers of combined GSTM1-null, GSTT1-active, GSTA1-low activity and GSTP1-variant genotype, exhibiting 9.32-fold elevated cRCC risk compared to the reference genotype combination (p = 0.04). Significant association between GST genotype and cRCC risk in smokers was found only for the GSTP1 genotype, while GSTM1-null/GSTP1-variant/GSTA1 low-activity genotype combination was present in 94% of smokers with cRCC, increasing the risk of cRCC up to 7.57 (p = 0.02). Furthermore, cRCC smokers with GSTM1-null genotype had significantly higher concentration of BPDE-DNA adducts in comparison with GSTM1-active cRCC smokers (p = 0.05). GSTM1, GSTT1, GSTA1 and GSTP1 polymorphisms might be associated with the risk of cRCC, with special emphasis on GSTM1-null and GSTP1-variant genotypes. Combined GSTM1-null, GSTT1-active, GSTA1 low activity and GSTP1-variant genotypes might be considered as "risk-carrying genotype combination" in cRCC.

GSTT1 Null Genotype Significantly Increases the Susceptibility to Urinary System Cancer: Evidences from 63,876 Subjects

GSTT1 gene plays an important role in detoxification and clearance of reactive oxygen species(ROS). A null variant in this gene has been demonstrated to confer cancer susceptibility. Although many studies have demonstrated the association between GSTT1 null polymorphism and urinary system cancer susceptibility, several publications reported opposite conclusions. For better understanding the effects of this polymorphism on the risk of urinary system cancer, a updated meta-analysis was performed with a total of 26,666 cases and 37,210 controls extracted from 117 studies, by following the latest meta-analysis guidelines (PRISMA). The results suggested that the GSTT1 null genotype was significantly associated with an increased risk of urinary system cancer (OR=1.13, 95%CI=1.05-1.22). Furthermore, stratified analyses by the type of cancer, ethnicity, source of control and quality score presented a significantly increased risk associated with GSTT1 null genotype in bladder and prostate cancer subgroup, Caucasians and Indians subgroup, population-based(PB) subgroup, medium quality and low quality subgroup. Overall, our meta-analysis suggested that GSTT1 null genotype is a potential cancer susceptibility variant. Well-designed and large-cohort studies are needed to confirm the association between GSTT1 null genotype and urinary system cancer risk.

GSTM1 and GSTT1 polymorphisms contribute to renal cell carcinoma risk: evidence from an updated meta-analysis

Emerging evidences suggest that GSTM1 and GSTT1 are involved in the detoxification of carcinogens, and polymorphisms in this gene that result in a loss of enzyme activity may increase the risk of renal cell carcinoma (RCC). Thus, to evaluate the association of GSTM1 and GSTT1 polymorphisms and RCC, we performed an updated meta-analysis of 10 case-control studies by RevMan 5.2, and the publication bias was tested using STATA 11.0. The meta-analysis showed that the single locus GSTM1 and GSTT1 polymorphisms were not significantly associated with a risk of RCC in a recessive model. However, that wild-type genotype versus the dual null genotype of GSTM1-GSTT1 showed a positive association with RCC risk (OR = 0.70; 95% CI = 0.51-0.98; P = 0.04). In another analysis of subjects exposed to pesticides, we found that the GSTM1 wild-type genotype was associated with increased RCC risk in Europeans (OR = 2.72; 95% CI = 1.54-4.82; P = 0.0006). We also identified an association between the GSTT1 wild-type and lower RCC TNM staging (I + II versus III + IV: OR = 1.88; 95% CI = 1.09-3.26; P = 0.02). This meta-analysis suggests that there may be a relationship between the GSTM1 and GSTT1 wild-type genotype and RCC.

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.

Glutathione-S-transferase-pi (GST-pi) expression in renal cell carcinoma

Multidrug resistance correlates with unfavourable treatment outcomes in numerous cancers including renal cell carcinoma. The expression and clinical relevance of Glutathione-S-transferase-pi (GST-pi), a multidrug resistance factor, in kidney tumors remain controversial. We analyzed the expression of GST-pi in 60 formalin-fixed, paraffin-embedded renal cell carcinoma samples by immunohistochemistry and compared them with matched normal regions of the kidney. A significantly higher expression of GST-pi was observed in 87% of clear cell carcinoma and 50% of papillary subtypes. GST-pi expression did not correlate with tumor grade or patient survival. GST-pi is unlikely to be a prognostic factor for renal cell carcinoma. However, further studies with large number of samples are warranted to establish the role of GST-pi, if any, in intrinsic or acquired resistance of renal cell carcinoma to conventional treatments.

XRCC1 gene polymorphisms and glioma risk in Chinese population: a meta-analysis

Background

Three extensively investigated polymorphisms (Arg399Gln, Arg194Trp, and Arg280His) in the X-ray repair cross-complementing group 1 (XRCC1) gene have been implicated in risk for glioma. However, the results from different studies remain inconsistent. To clarify these conflicts, we performed a quantitative synthesis of the evidence to elucidate these associations in the Chinese population.

Methods

Data were extracted from PubMed and EMBASE, with the last search up to August 21, 2014. Meta-analysis was performed by critically reviewing 8 studies for Arg399Gln (3062 cases and 3362 controls), 8 studies for Arg194Trp (3419 cases and 3680 controls), and 5 studies for Arg280His (2234 cases and 2380 controls). All of the statistical analyses were performed using the software program, STATA (version 11.0).

Results

Our analysis suggested that both Arg399Gln and Arg194Trp polymorphisms were significantly associated with increased risk of glioma (for Arg399Gln polymorphism: Gln/Gln vs. Arg/Arg, OR = 1.82, 95% CI = 1.46–2.27, P = 0.000; Arg/Gln vs. Arg/Arg, OR = 1.25, 95% CI = 1.10–1.42, P = 0.001 and for Arg194Trp polymorphism: recessive model, OR = 1.78, 95% CI = 1.44–2.19, P = 0.000), whereas the Arg280His polymorphism had no influence on the susceptibility to glioma in a Chinese population.

Conclusions

This meta-analysis suggests that there may be no association between the Arg280His polymorphism and glioma risk, whereas the Arg399Gln/Arg194Trp polymorphisms may contribute to genetic susceptibility to glioma in the Chinese population. Nevertheless, large-scale, well-designed and population-based studies are needed to further evaluate gene-gene and gene–environment interactions, as well as to measure the combined effects of these XRCC1 variants on glioma risk.