The associations between two vital GSTs genetic polymorphisms and lung cancer risk in the Chinese population: evidence from 71 studies

Association of xenobiotic-metabolizing genes polymorphisms with cervical cancer risk in the Tunisian population

BACKGROUND

Host genetic characteristics and environmental factors interactions may play a crucial role in cervical carcinogenesis. We investigated the impact of functional genetic variants of four xenobiotic-metabolizing genes (AhR, CYP1A1, GSTM1, and GSTT1) on cervical cancer development in Tunisian women.

METHODS

The AhR gene polymorphism was analyzed using the tetra-primer ARMS-PCR, whereas the CYP1A1 polymorphism genotypes were identified by PCR-RFLP. A multiplex ligation-dependent polymerase chain reaction approach was applied for the analysis of GSTM1 and GSTT1 polymorphisms.

RESULTS

The homozygous A/A genotype of the AhR gene (rs2066853) and the heterozygous T/C genotype of the CYP1A1 SNP (CYP1A1-MspI) appeared to be associated with an increased risk of cervical tumorigenesis (OR^a = 2.81; OR^a = 5.52, respectively). Furthermore, a significantly increased risk of cervical cancer was associated with the GSTT1 null genotype (OR^a = 2.65). However, the null GSTM1 genotype showed any significant association with the risk of cervical cancer compared to the wild genotype (OR^a = 1.18; p = 0.784). Considering the combined effect, we noted a significantly higher association with cancer risk for individuals with at least two high-risk genotypes of CYP1A1/GSTT1 (OR^a = 4.2), individuals with at least two high-risk genotypes of CYP1A1/GSTT1/AhR (OR^a = 11.3) and individuals with at least two high-risk genotypes of CYP1A1/GSTM1/GSTT1/AhR exploitation low-risk genotype as a reference.

CONCLUSION

This study indicated that the single-gene contribution and the combined effect of xenobiotic-metabolizing gene polymorphisms (AhR, CYP1A1-MspI, GSTM1, and GSTT1) may have a considerable association with increased cervical cancer risk.

Relationship between GSTM1 and GSTT1 polymorphisms and HPV infection: a systematic review

Human Papillomavirus (HPV) is the most important risk factor for cervical cancer, although not the only one. The allelic polymorphism of enzymes acting on carcinogen metabolism has shown to influence the risk of both intraepithelial lesions and cervical carcinogenesis. Several studies found an association between GSTM1/GSTT1 null genotypes and risk of cancer. This research aimed to review studies addressing the relationship between GSTT1 and GSTM1 and HPV infection in women, with or without cervical pathologies. A database search was conducted in four databases - PubMed, LILACS, SciELO, and Virtual Health Library - using the following descriptors: Glutathione transferase, HPV, and Genetic polymorphism. In total, we found 319 studies. After screening titles and abstracts, 27 articles were selected for full-text read, among which 20 were excluded and 7 were included in the review. No study has exclusively approached the relationship between the virus and GSTM1/GSTT1 variants. However, studies investigating the association between single nucleotide polymorphisms (SNPs) and cervical lesions or cancer found a probable relationship between them and infections with high-risk oncogenic subtypes. Although inconclusive, GSTT1 null alleles were more common in women with more aggressive HPV than GSTM1.

Individual and combined effects of GSTM1, GSTT1, and GSTP1 polymorphisms on lung cancer risk: A meta-analysis and re-analysis of systematic meta-analyses

Thirty-five previous meta-analyses have been reported on the individual glutathione S-transferase M1 (GSTM1) present/null, glutathione S-transferase T1 (GSTT1) present/null, and glutathione S-transferase P1 (GSTP1) IIe105Val polymorphisms with lung cancer (LC) risk. However, they did not appraise the credibility and explore the combined effects between the 3 genes and LC risk.We performed a meta-analysis and re-analysis of systematic previous meta-analyses to solve the above problems.Meta-analyses of Observational Studies in Epidemiology guidelines were used. Moreover, we employed false-positive report probability (FPRP), Bayesian false discovery probability (BFDP), and the Venice criteria to verify the credibility of current and previous meta-analyses.Significantly increased LC risk was considered as "highly credible" or "positive" for GSTM1 null genotype in Japanese (odds ratio (OR) = 1.30, 95% confidence interval (CI) = 1.17-1.44, I2 = 0.0%, statistical power = 0.997, FPRP = 0.008, BFDP = 0.037, and Venice criteria: AAB), for GSTT1 null genotype in Asians (OR = 1.23, 95% CI = 1.12-1.36, I2 = 49.1%, statistical power = 1.000, FPRP = 0.051, BFDP = 0.771, and Venice criteria: ABB), especially Chinese populations (OR = 1.31, 95% CI = 1.16-1.49, I2 = 48.9%, Statistical power = 0.980, FPRP = 0.039, BFDP = 0.673, and Venice criteria: ABB), and for GSTP1 IIe105Val polymorphism in Asians (Val vs IIe: OR = 1.28, 95% CI = 1.17-1.42, I2 = 30.3%, statistical power = 0.999, FPRP = 0.003, BFDP = 0.183, and Venice criteria: ABB). Significantly increased lung adenocarcinoma (AC) risk was also considered as "highly credible" or "positive" in Asians for the GSTM1 (OR = 1.35, 95% CI = 1.22-1.48, I2 = 25.5%, statistical power = 0.988, FPRP < 0.001, BFDP < 0.001, and Venice criteria: ABB) and GSTT1 (OR = 1.36, 95% CI = 1.17-1.58, I2 = 30.2%, statistical power = 0.900, FPRP = 0.061, BFDP = 0.727, and Venice criteria: ABB) null genotype.This study indicates that GSTM1 null genotype is associated with increased LC risk in Japanese and lung AC risk in Asians; GSTT1 null genotype is associated with increased LC risk in Chinese, and GSTP1 IIe105Val polymorphism is associated with increased LC risk in Asians.

The Association of Aging-Related Polymorphisms with Susceptibility to Lung Cancer: A Case-Control Study in a Japanese Population

BACKGROUND

Telomere length is associated with cancer as well as aging.  Telomerase reverse transcriptase (TERT), telomere RNA component (TERC) and oligonucleotide/oligosaccharide-binding fold containing 1 (OBFC1) are known to be involved in telomere length regulation. The tumor suppressor p53 (TP53), which has been shown to interact with tumor protein p53-binding protein 1 (TP53BP1), is implicated in the response to telomere shortening and aging.  Polymorphisms in the TP53 and TP53BP1 genes are associated with various types of cancer. The aim of this study is to evaluate the impact of aging-related polymorphisms on lung cancer risk.

MATERIALS AND METHODS

This case-control study consists of 462 lung cancer cases and 379 controls from Japan.  We examined the effect of TERT rs2736100, TERC rs1881984, OBFC1 rs11191865, TP53 rs1042522 and TP53BP1 rs560191 on the risk of lung cancer using a Taq-Man real-time PCR assay. Unconditional logistic regression was used to assess the adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

None of the main effects of any of the telomere-related polymorphisms were related to the risk of lung cancer.  Similarly, none of the interactive effects of any of the telomere-related polymorphisms with smoking were associated with lung cancer risk. The significant multiplicative interaction between TERT rs2736100 and TP53BP1 rs560191 was statistically significant (OR for interaction = 0.34, 95% CI = 0.14-0.84). The multiplicative interaction between OBFC1 rs11191865 and TP53BP1 rs560191 was also statistically significant (OR for interaction = 2.44, 95% CI = 1.02-5.87) but the OR for interaction was in the opposite direction.

CONCLUSIONS

Our findings indicate that TP53BP1 rs560191 may predispose to lung cancer risk depending on the genotypes of telomere-related polymorphisms. Additional studies are warranted to confirm the findings suggested in the present study.<br />.

Glutathione S-transferase gene polymorphisms (GSTT1 and GSTM1) and risk of schizophrenia: A case-control study in Chinese Han population

Schizophrenia (SCZ) is a chronic disability disorder related to oxidative stress. Glutathione S-transferase (GST) is a group enzyme that protects cells and tissues from oxidative stress damage. Among GSTs, GSTT1 and GSTM1 have well defined genetic polymorphisms. The purpose of our research was to explore the correlation between GSTT1 and GSTM1 polymorphism and SCZ risk in Chinese Han population.A total of 650 subjects (386 SCZ patients and 264 healthy individuals) were included in this case-control designed study. The GSTT1 and GSTM1 polymorphisms were analyzed by multiplex polymerase chain reaction (PCR). We explored the relationship between these 2 polymorphisms and the risk of SCZ.We found that the GSTT1 null genotype had a protective effect on the development of SCZ [odds ratio (OR) = 0.601, 95% confidence interval (95% CI) = 0.412-0.986, P = .031]. We also found that the combination of null genotypes of the GSTT1 and GSTM1 genes was made at a lower risk of SCZ (OR = 0.452, 95% CI = 0.238-0.845, P = .028). However, we found no correction between Positive and Negative Syndrome Scale score (PANSS) and GSTM1, GSST1 genotypes in SCZ patients.Our finding revealed that GSTT1 null polymorphisms may be related to the reduced risk of SCZ in Chinese Han population, and this risk was further reduced with the combination of GSTT1 null polymorphisms and GSTM1 null polymorphisms.

Glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) Polymorphisms and Lung Cancer Risk among a Select Group of Iranian People

Objective(s): Lung cancer, caused primarily by smoking, is one of the leading determinants of mortality throughout the world. Here we investigated the effects of polymorphisms in two enzymes, i.e., GSTT1 and GSTM1, related to the antioxidant defense line against carcinogens associated with lung cancer among a select group of Iranian people. Materials and Methods: One hundred and twenty lung cancer patients from two referral centers in Tehran, Iran, were recruited for comparison with 120 healthy controls. Genomic DNA was extracted from the FFPE tumor tissues of the select cases and peripheral blood buffy coats of healthy controls. The polymorphisms of GSTT1 and GSTM1 were investigated by multiplex polymerase chain reaction. Results: With the 240 samples studied, no specific relationship with lung cancer was discerned for the GSTM1 (P=0.35; OR=1/33; 95% CI=0.79-2.25) polymorphism, but the GSTT1 (P=0.005; OR=2.4; CI=1.32-4.35) gene polymorphism revealed a notable association on logistic regression, taking into account age and sex factors. Furthermore, the GSTT1 genotype distribution in patients with LSCC was different from that of healthy cases (P=0.006; OR=3.11; CI=1.38-7.04). The risk of developing lung cancer with the T0M1 genotype was 3.46 times higher than with T1M1 genotype (P=0.002; OR=3.46; CI=1.61-7.46). Moreover, the risk of developing LSCC cancer in people with T0M1 genotypes was significantly elevated (P=0.004; OR=4.5; CI=1.62-12.52). Conclusion: Unlike GSTM1, the GSTT1 genotype distribution is associated with the incidence of lung cancer in Iranian people. Different types of lung cancer appear to show various correlations with GST polymorphisms in this regard.

Lung cancer susceptibility from GSTM1 deletion and air pollution with smoking status: a meta-prediction of worldwide populations

Glutathione S transferase mu 1 (GSTM1) gene has been associated with lung cancer (LC) risk, for GSTM1 enzyme playing a vital role in detoxification pathway and protective against toxic insults. The major objective of this study was to investigate GSTM1 deletion pattern and its association with LC in the world’s population by using meta-prediction techniques. The secondary objective was to examine the effects of air pollution, smoking status, and other factors for gene-environment interactions with GSTM1 deletion and LC risk. We completed a comprehensive search to yield a total of 170 studies (40,296 cases and 48,346 controls) published from 1999 to 2017 for meta-analyses. The results revealed that GSTM1 deletion type was associated with increased risk of LC, while GSTM1 present type provided protective effect for all populations combined worldwide. Subgroup analysis on the rank order of risks from highest to lowest, among racial–ethnic groups, were Chinese, South East Asian, other North Asian, European, and finally American. Additional predictive analyses presented that air pollution played a significant role with increased risks of GSTM1 deletion and LC susceptibility, and the risks increased for smokers with higher levels of air pollution. Based on the findings of meta-predictive analysis, increased air pollution levels and smoking status presented additive effects to the LC risk susceptibilities and GSTM1 gene polymorphisms, for gene-environment interactions. Future studies are needed to examine gene-environment interactions for GSTM1 interacting with environmental factors and dietary interventions to mitigate the toxic effects, for LC prevention.

Downregulation of Glutathione S-transferase A1 suppressed tumor growth and induced cell apoptosis in A549 cell line

Glutathione S-transferase A1 (GSTA1) is a phase II detoxification enzyme and serves a crucial role in anti-cancer drug resistance. In our previous study, GSTA1 was identified to be highly expressed in various subtypes of non-small-cell lung cancer cell lines compared with human embryonic lung fibroblast cell line MRC-5. The aim of the present study was to investigate the effect of GSTA1 expression on the proliferation and apoptosis of A549 cells. GSTA1 expression was knocked down or with overexpressed using lentivirus particles. Western blot analysis and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were used to assess the protein, and mRNA levels of GSTA1 in A549 cells, respectively. The effect of GSTA1 manipulation on cell proliferation and apoptosis were investigated in vitro using MTT assays, Hoechst 33258 staining and flow cytometry, and in vivo using A549 cell line xenografts in nude mice. The results of the western blot analysis and RT-qPCR revealed that stable cell models of GSTA1 knockdown, and overexpression were established. The data of the MTT assay indicated that the downregulation of GSTA1 significantly inhibited cell proliferation compared with si-control-transfected cells. These si-GSTA1 A549 cells exhibited typical morphological changes of apoptosis, including chromatin condensation and shrunken nuclei compared with the si-control counterparts. An AnnexinV-fluorescein isothiocyanate assay verified that the downregulation of GSTA1 significantly induced cell apoptosis in vitro. In addition, overexpression of GSTA1 significantly promoted tumor growth in vivo. Accordingly, downregulation of GSTA1 suppressed tumor growth. In conclusion, GSTA1 plays an important role in regulation of cell proliferation and cell apoptosis in A549 cell line.

Genetic polymorphisms and lung cancer risk: Evidence from meta-analyses and genome-wide association studies

A growing number of studies investigating the association between Single Nucleotide Polymorphisms (SNPs) and lung cancer risk have been published since over a decade ago. An updated integrative assessment on the credibility and strength of the associations is required. We searched PubMed, Medline, and Web of Science on or before August 29^th, 2016. A total of 198 articles were deemed eligible for inclusion, which addressed the associations between 108 variants and lung cancer. Among the 108 variants, 63 were reported to be significantly associated with lung cancer while the remaining 45 were reported non-significant. Further evaluation integrating the Venice Criteria and false-positive report probability (FPRP) was performed to determine the strength of cumulative epidemiological evidence for the 63 significant associations. As a result, 15 SNPs on or near 12 genes and one miRNA with strong evidence of association with lung cancer risk were identified, including TERT (rs2736098), CHRNA3 (rs1051730), AGPHD1 (rs8034191), CLPTM1L (rs401681 and rs402710), BAT3 (rs3117582), TRNAA (rs4324798), ERCC2 (Lys751Gln), miR-146a2 (rs2910164), CYP1B1 (Arg48Gly), GSTM1 (null/present), SOD2 (C47T), IL-10 (-592C/A and -819C/T), and TP53 (intron 6). 19 SNPs were given moderate rating and 17 SNPs were rated as having weak evidence. In addition, all of the 29 SNPs identified in 12 genome-wide association studies (GWAS) were proved to be noteworthy based on FPRP value. This review summarizes and evaluates the cumulative evidence of genetic polymorphisms and lung cancer risk, which can serve as a general and useful reference for further genetic studies.

Genetic susceptibility of lung cancer in Chinese population: An overview of systematic reviews and meta-analyses

BACKGROUND

Genetic susceptibility of lung cancer has been widely studied for Chinese population, and meta-analysis of candidate gene association studies has also been performed for those genes. However, the overall evidence has not been well recognized.

OBJECTIVE

To investigate genetic association for the risk of lung cancer in Chinese.

METHOD

An overview of systematic reviews and meta-analyses of candidate gene association studies for lung cancer in Chinese was performed up to August 10^th , 2016. The AMSTAR tool was used to assess the quality of the included systematic reviews and meta-analyses. Bibliometric analysis was performed to analyze the characteristics of reviews.

RESULTS

A total of 21 variants in 17 genes from 20 meta-analyses were included in this study. All 20 meta-analyses were published from 2011 to 2016. The quality scores of AMSTAR ranged from 3 to 7. All included genes were in the pathogenesis of lung cancer, such as the CYPs genes, GSTs genes, and base excision repair genes. Three polymorphisms were found to be associated with decreased risk of lung cancer for Chinese, 15 polymorphisms were found to be associated with increased risk of lung cancer for Chinese, but three polymorphisms were found to be not associated with lung cancer risk for Chinese.

CONCLUSION

The current study supports the genetic risk factors of lung cancer for Chinese are more likely to be variants from genes that contribute to the etiology of lung cancer.

Regulation of MAPKs Signaling Contributes to the Growth Inhibition of 1,7-Dihydroxy-3,4-dimethoxyxanthone on Multidrug Resistance A549/Taxol Cells

1,7-Dihydroxy-3,4-dimethoxyxanthone (XAN) is a bioactive compound isolated from Securidaca inappendiculata Hassk. and validated with antiproliferative activities on a panel of cancer cell lines. This study was designed to investigate its growth inhibitory effects on multidrug resistance (MDR) non-small cell lung carcinoma (NSCLC) cell line A549/Taxol and explore the possible linkage between modulation of MAPKs and the bioactivities. Its growth inhibitory potency on the cells was estimated by MTT assay, and flow cytometric analysis was employed to investigate its potential cell cycle arrest and proapoptosis effects. Expressions of hallmark proteins were assessed by Western-Blot method. The results showed A549/Taxol cells were sensitive to XAN. XAN inhibited the proliferation of A549/Taxol cells in the time and concentration dependent manners. It acted as a potent inducer of apoptosis and cell cycle arrest in the cells. Western-Blot investigation validated the proapoptosis and cell cycle arrest activities of XAN and the potential of MDR reversion. Upregulation of p38 by XAN, which accounted for the cell cycle arrest at G2 phase, and the downregulation of ERK associated with the proapoptosis activity were also revealed. Further analysis found p53 may be the central role mediated the bioactivities of MAPKs in A549/Taxol cells. Based on these evidences, a conclusion has been deduced that XAN could be a potential agent for MDR NSCLC therapy targeting specifically MAPKs.

Epistasis Test in Meta-Analysis: A Multi-Parameter Markov Chain Monte Carlo Model for Consistency of Evidence

Conventional genome-wide association studies (GWAS) have been proven to be a successful strategy for identifying genetic variants associated with complex human traits. However, there is still a large heritability gap between GWAS and transitional family studies. The "missing heritability" has been suggested to be due to lack of studies focused on epistasis, also called gene-gene interactions, because individual trials have often had insufficient sample size. Meta-analysis is a common method for increasing statistical power. However, sufficient detailed information is difficult to obtain. A previous study employed a meta-regression-based method to detect epistasis, but it faced the challenge of inconsistent estimates. Here, we describe a Markov chain Monte Carlo-based method, called "Epistasis Test in Meta-Analysis" (ETMA), which uses genotype summary data to obtain consistent estimates of epistasis effects in meta-analysis. We defined a series of conditions to generate simulation data and tested the power and type I error rates in ETMA, individual data analysis and conventional meta-regression-based method. ETMA not only successfully facilitated consistency of evidence but also yielded acceptable type I error and higher power than conventional meta-regression. We applied ETMA to three real meta-analysis data sets. We found significant gene-gene interactions in the renin-angiotensin system and the polycyclic aromatic hydrocarbon metabolism pathway, with strong supporting evidence. In addition, glutathione S-transferase (GST) mu 1 and theta 1 were confirmed to exert independent effects on cancer. We concluded that the application of ETMA to real meta-analysis data was successful. Finally, we developed an R package, etma, for the detection of epistasis in meta-analysis [etma is available via the Comprehensive R Archive Network (CRAN) at https://cran.r-project.org/web/packages/etma/index.html].

GSTT1 and GSTM1 polymorphisms predict treatment outcome for breast cancer: a systematic review and meta-analysis

Observational studies have reported controversial results on the association between GSTT1 and GSTM1 genotypes and treatment outcome of breast cancer. The purpose of this study is to evaluate the association between GSTT1 and GSTM1 and treatment outcome in breast cancer patients. Eligible studies were searched in PubMed, EMBASE, Cochrane Library, and China National Knowledge Infrastructure databases. A random-effect model or fixed-effect model was used to calculate the overall combined risk estimates. Twenty-one studies with a total of 4990 patients were included in this meta-analysis. The GSTM1 null genotype (odds ratio (OR) = 1.33, 95 % confidence interval (CI) 1.01-1.75, P = 0.046) and GSTT1/GSTM1 double null genotype (OR = 2.22, 95 % CI 1.02-4.84, P = 0.045) were significantly associated with an increased tumor response. A reduced overall survival (hazard ratio (HR) = 0.84, 95 % CI 0.72-0.98, P = 0.024) was observed in GSTM1 null genotype, especially in mixed descent (HR = 0.77, 95 % CI 0.61-0.96, P = 0.018) and large sample size (HR = 0.85, 95 % CI 0.72-0.99, P = 0.033). Evidence of publication bias was observed in GSTM1 genotype rather than in GSTT1 genotype. This meta-analysis suggests that GSTM1 null and GSTT1/GSTM1 double null polymorphisms might be significantly associated with an increased tumor response. However, the GSTM1 null genotype might be significantly associated with a reduced overall survival. Future studies are warranted to confirm these findings.

The association of GSTT1 deletion polymorphism with lung cancer risk among Chinese population: evidence based on a cumulative meta-analysis

OBJECTIVE

Previous studies investigating the relationship between glutathione S-transferase T1 (GSTT1) gene deletion polymorphism and lung cancer risk among Chinese population produced inconsistent results. To obtain a precise conclusion, we performed this meta-analysis to evaluate the association between GSTT1 deletion polymorphism and lung cancer risk among Chinese population.

METHODS

The databases of Medline/PubMed, Embase, Web of Science, Wanfang Med Online, and Chinese National Knowledge Infrastructure were searched. The strength of the association was assessed by odds ratio (OR) with 95% confidence intervals (95% CI).

RESULTS

Overall, we found an increased lung cancer risk among subjects carrying GSTT1 null genotype compared with those carrying present genotype (OR =1.31, 95% CI: 1.12-1.52) on the basis of 20 studies with 3,351 cases and 4,683 controls. We also observed an increased risk of lung cancer among subjects carrying GSTT1 null genotype compared with those carrying present genotype in stratified analyses (OR =1.31, 95% CI: 1.11-1.55 for healthy subjects-based control; OR =2.29, 95% CI: 1.84-2.85 for squamous cell carcinoma and OR =1.47, 95% CI: 1.22-1.77 for adenocarcinoma, respectively).

CONCLUSION

This meta-analysis suggested that GSTT1 deletion polymorphism might contribute to lung cancer risk among Chinese population.

The association of GSTM1 deletion polymorphism with lung cancer risk in Chinese population: evidence from an updated meta-analysis

Previous studies have reported the association of glutathione S-transferase M1 (GSTM1) deletion polymorphism with genetic susceptibility of lung cancer in Chinese population. However, the results remained controversial. The aim of this study was to clarify the association of GSTM1 deletion polymorphism with lung cancer risk in Chinese population. Systematic searches were performed through the search engines of Medline/Pubmed, Web of Science, EMBASE, CNKI and Wanfang Medical Online. The pooled effects were calculated by STATA 10.0 software package and Review Manager 5.0.24. Overall, we observed an association of GSTM1 deletion polymorphism with increased lung cancer risk in Chinese population (odds ratio (OR) = 1.46, 95% confidence interval (95%CI): 1.32-1.66 for null genotype vs. present genotype) based on 53 studies including 7,833 cases and 10,353 controls. We also observed an increased risk of GSTM1 null genotype for lung cancer in stratified analyses by source of control, smoking status and histological type. The findings suggest that GSTM1 deletion polymorphism may contribute to lung cancer risk in Chinese population. Further, well-designed studies with larger sample sizes are required to verify the results.

An Updated Meta-Analysis: Risk Conferred by Glutathione S-Transferases (GSTM1 and GSTT1) Polymorphisms to Age-Related Cataract

Purpose. To study the effects of glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) polymorphisms on age-related cataract (ARC). Methods. After a systematic literature search, all relevant studies evaluating the association between GSTs polymorphisms and ARC were included. Results. Fifteen studies on GSTM1 and nine studies on GSTT1 were included in this meta-analysis. In the pooled analysis, a significant association between null genotype of GSTT1 and ARC was found (OR = 1.229, 95% CI = 1.057–1.429, and P = 0.007). In subgroup analysis, the association between cortical cataract (CC) and GSTM1 null genotype was statistically significant (OR = 0.713, 95% CI = 0.598–0.850, and P < 0.001). In addition, GSTM1 null genotype was significantly associated with ARC causing risk to individuals working indoors and not individuals working outdoors. The association between GSTT1 null genotype and risk of ARC was statistically significant in Asians (OR = 1.442, 95% CI = 1.137–1.830, and P = 0.003) but not in Caucasians. Conclusions. GSTM1 positive genotype is associated with increased risk of CC and loses the protective role in persons who work outdoors. Considering the ethnic variation, GSTT1 null genotype is found to be associated with increased risk of ARC in Asians but not in Caucasians.

PARP and other prospective targets for poisoning cancer cell metabolism

Increasing evidence indicates that cancer cells rewire their metabolism during tumorigenesis. The high intracellular levels of lactate and reactive oxygen species (ROS) generated during enhanced aerobic glycolysis and mitochondrial oxidative phosphorylation respectively led to oxidative stress. The detoxification of these accumulating metabolites and the equilibrium between reduced and oxidized nicotine adenine dinucleotide (NADH and NAD(+)) are two prominent mechanisms regulating redox status and hence energy homeostasis in tumors. Targeting both processes may thus be selectively cytotoxic for cancer cells. In this context, the impact of poly(ADP-ribose) polymerase (PARP) inhibitors, a class of anticancer agents employed for the treatment of DNA repair deficient tumors, on energy homeostasis and mitochondrial respiration regulation has potential clinical implications. Here we provide an overview of the metabolic reprogramming occurring in cancer cells and discuss the translational perspectives of targeting tumor metabolism and redox balance for antineoplastic therapy.