Are glutathione S transferases involved in DNA damage signalling? Interactions with DNA damage and repair revealed from molecular epidemiology studies. Mutat Res. 2012;736:130-137. [PMID: 22450146 DOI: 10.1016/j.mrfmmm.2012.03.003]

Genetic Variability Impacts Genotoxic and Transcriptome Responses in the Human Colon after the Consumption of Processed Red Meat Products and Those with Added Phytochemical Extracts

The PHYTOME study investigated the effect of consuming processed meat products on outcomes related to colorectal cancer risk without testing the impact of genetic variability on these responses. This research aims to elucidate the genetic impact on apparent total N-nitroso compound (ATNC) excretion, colonic DNA adduct formation, ex vivo-induced DNA damage, and gene expression changes in colon biopsies of healthy participants. Through a systematic literature review, candidate polymorphisms were selected and then detected using TaqMan and PCR analysis. The effect of genotype on study outcomes was determined via a linear mixed model and analysis of variance. Machine learning was used to evaluate relative allele importance concerning genotoxic responses, which established a ranking of the most protective alleles and a combination of genotypes (gene scores). Participants were grouped by GSTM1 genotype and differentially expressed genes (DEGs), and overrepresented biological pathways were compared between groups. Stratifying participants by ten relevant genes revealed significant variations in outcome responses. After consumption of processed red meat, variations in NQO1 and COMT impacted responses in ATNC levels (µmol/L) (+9.56 for wildtype vs. heterozygous) and DNA adduct levels (pg/µg DNA) (+1.26 for variant vs. wildtype and +0.43 for variant vs. heterozygous), respectively. After phytochemicals were added to the meat, GSTM1 variation impacted changes in DNA adduct levels (-6.12 for deletion vs. wildtype). The gene scores correlated with these responses and DEGs were identified by GSTM1 genotype. The altered pathways specific to the GSTM1 wildtype group included 'metabolism', 'cell cycle', 'vitamin D receptor', and 'metabolism of water-soluble vitamins and co-factors'. Genotype impacted both the potential genotoxicity of processed red meat and the efficacy of protective phytochemical extracts.

Air Pollution and Diet: Potential Interacting Exposures in Asthma

PURPOSE OF REVIEW

To provide a review of emerging literature describing the impact of diet on the respiratory response to air pollution in asthma.

RECENT FINDINGS

Asthma phenotyping (observable characteristics) and endotyping (mechanistic pathways) have increased the specificity of diagnostic and treatment pathways and opened the doors to the identification of subphenotypes with enhanced susceptibility to exposures and interventions. Mechanisms underlying the airway immune response to air pollution are still being defined but include oxidative stress, inflammation, and activation of adaptive and innate immune responses, with genetic susceptibility highlighted. Of these, neutrophil recruitment and activation appear prominent; however, understanding neutrophil function in response to pollutant exposures is a research gap. Diet may play a role in asthma pathogenesis and morbidity; therefore, diet modification is a potential target opportunity to protect against pollutant-induced lung injury. In particular, in vivo and in vitro data suggest the potential for diet to modify the inflammatory response in the airways, including impacts on neutrophil recruitment and function. Murine models provide compelling results in regard to the potential for dietary components (including fiber, antioxidants, and omega-3 fatty acids) to buffer against the inflammatory response to air pollution in the lung. Precision lifestyle approaches to asthma management and respiratory protection in the context of air pollution exposures may evolve to include diet, pending the results of further epidemiologic and causal investigation and with neutrophil recruitment and activation as a candidate mechanism.

Genotoxic effects of occupational exposure to glass fibres - A human biomonitoring study

As part of a large human biomonitoring study, we conducted occupational monitoring in a glass fibre factory in Slovakia. Shopfloor workers (n = 80), with a matched group of administrators in the same factory (n = 36), were monitored for exposure to glass fibres and to polycyclic aromatic hydrocarbons (PAHs). The impact of occupational exposure on chromosomal aberrations, DNA damage and DNA repair, immunomodulatory markers, and the role of nutritional and lifestyle factors, as well as the effect of polymorphisms in metabolic and DNA repair genes on genetic stability, were investigated. The (enzyme-modified) comet assay was employed to measure DNA strand breaks (SBs) and apurinic sites, oxidised and alkylated bases. Antioxidant status was estimated by resistance to H₂O₂-induced DNA damage. Base excision repair capacity was measured with an in vitro assay (based on the comet assay). Exposure of workers to fibres was low, but still was associated with higher levels of SBs, and SBs plus oxidised bases, and higher sensitivity to H₂O₂. Multivariate analysis showed that exposure increased the risk of high levels of SBs by 20%. DNA damage was influenced by antioxidant enzymes catalase and glutathione S-transferase (measured in blood). DNA repair capacity was inversely correlated with DNA damage and positively with antioxidant status. An inverse correlation was found between DNA base oxidation and the percentage of eosinophils (involved in the inflammatory response) in peripheral blood of both exposed and reference groups. Genotypes of XRCC1 variants rs3213245 and rs25487 significantly decreased the risk of high levels of base oxidation, to 0.50 (p = 0.001) and 0.59 (p = 0.001), respectively. Increases in DNA damage owing to glass fibre exposure were significant but modest, and no increases were seen in chromosome aberrations or micronuclei. However, it is of concern that even low levels of exposure to these fibres can cause significant genetic damage.

iTRAQ-based quantitative proteomic analysis of the liver regeneration termination phase after partial hepatectomy in mice

Liver regeneration (LR) is an important biological process after liver injury. As the "brake" in the process of LR, the termination phase of LR not only suppresses the continuous increase in liver volume but also effectively promotes the recovery of liver function. However, the mechanisms underlying the termination phase of LR are still not clear. In our study, we used isobaric tags for relative and absolute quantification (iTRAQ)-based quantitative proteomic analysis to determine the protein expression profiles of livers in the termination phase of mouse LR after partial hepatectomy (PH). We found that the expression of 197 proteins increased gradually during LR; in addition, 187 proteins were upregulated and 264 proteins were downregulated specifically in the termination phase of LR. The GO analysis of the proteins revealed the upregulation of "cell-cell adhesion" and "translation" and the downregulation of the "oxidation-reduction process". The KEGG pathway analysis showed that "biosynthesis of antibiotics" and "ribosomes" were significantly upregulated, while "metabolic pathways" were significantly downregulated. These analyses indicated that the termination phase of LR mainly focuses on restoring cellular structure and function. Differentially expressed proteins such as SNX5 were also screened out from biological processes. SIGNIFICANCE: The key regulatory factors in the termination phase of LR were studied by iTRAQ-based proteomics to lay a foundation for further study of the molecular mechanism and biomarkers of the termination phase of LR. This study will guide the clinical perioperative management of patients after hepatectomy.

Serum levels of vitamin A, selenium and better dietary total antioxidant capacity are related to lower oxidative DNA damage: a cross-sectional study of individuals at cardiovascular risk

The risk for cardiovascular diseases (CVR) has been associated with oxidative DNA damage, but the genetic and environmental factors involved in the antioxidant and DNA repair system contributing to this damage are unknown. The aim was to evaluate the levels of oxidative DNA damage in CVR subjects and how it is related with some genetic and nutritional factors. The cross-sectional study evaluated 136 individuals of both sexes, aged 20-59 years, with at least one cardiovascular risk factor. The global risk score was used to classify individuals at low, intermediate and high cardiovascular risk. The dietary total antioxidant capacity (DTAC) was calculated using table with FRAP values. The oxidative DNA damage was verified by the comet assay. The variants null of Glutathione-S-transferases Mu1 and Theta 1(GSTM1 and GSTT1) and rs25487 of X-Ray Repair Cross Complementing Protein 1 (XRCC1) were analyzed by real-time PCR and PCR-RFLP, respectively. The oxidative DNA damage was higher in patients with intermediate/high CVR than in patients with low CVR (p=0.01). Individuals with GSTT1/GSTM1 null genotypes or arg/gln + gln/gln genotypes of the XRCC1 (rs25487) gene showed similar levels of oxidative DNA damage compared wild genotype. Multivariate regression analysis demonstrated that oxidative DNA damage in individuals with CVR depends on serum levels of vitamin A, selenium and DTAC independently of the other factors [F(6.110)=8.213; p<0.001; R2=0.330]. These findings suggest that nutritional factors such as DTAC, vitamin A and selenium may have a protective effect against oxidative DNA damage in these individuals.

A pooled analysis of molecular epidemiological studies on modulation of DNA repair by host factors

Levels of DNA damage represent the dynamics between damage formation and removal. Therefore, to better interpret human biomonitoring studies with DNA damage endpoints, an individual's ability to recognize and properly remove DNA damage should be characterized. Relatively few studies have included DNA repair as a biomarker and therefore, assembling and analyzing a pooled database of studies with data on base excision repair (BER) was one of the goals of hCOMET (EU-COST CA15132). A group of approximately 1911 individuals, was gathered from 8 laboratories which run population studies with the comet-based in vitro DNA repair assay. BER incision activity data were normalized and subsequently correlated with various host factors. BER was found to be significantly higher in women. Although it is generally accepted that age is inversely related to DNA repair, no overall effect of age was found, but sex differences were most pronounced in the oldest quartile (>61 years). No effect of smoking or occupational exposures was found. A body mass index (BMI) above 25 kg/m² was related to higher levels of BER. However, when BMI exceeded 35 kg/m², repair incision activity was significantly lower. Finally, higher BER incision activity was related to lower levels of DNA damage detected by the comet assay in combination with formamidopyrimidine DNA glycosylase (Fpg), which is in line with the fact that oxidatively damaged DNA is repaired by BER. These data indicate that BER plays a role in modulating the steady-state level of DNA damage that is detected in molecular epidemiological studies and should therefore be considered as a parallel endpoint in future studies.

The Relationship Between GSTT1, GSTM1, GSTO1, GSTP1 and MTHFR Gene Polymorphisms and DNA Damage of BRCA1 and BRCA2 Genes in Arsenic-Exposed Workers

OBJECTIVE

To investigate the associations between genetic polymorphisms of GSTT1, GSTM1, GSTO1, GSTP1 and MTHFR genes and the DNA damage levels of BRCA1 and BRCA2 genes.

METHODS

Peripheral blood samples were used to measure DNA damage levels and genetic polymorphisms, and urine samples were collected to analyze arsenic metabolites in 79 arsenic-exposed workers and 24 non-arsenic-exposed workers.

RESULTS

The BRCA1 and BRCA2 damage levels in exposure group were significantly higher than that in control group. Significant associations were detected between GSTT1 and GSTO1 polymorphisms and DNA damage levels of BRCA1 and BRCA2 genes in subjects (P < 0.05).

CONCLUSIONS

Our findings suggest that the DNA damage levels of BRCA1 and BRCA2 genes may modulate by genetic variations of GSTT1 and GSTO1 when individuals are exposed to carcinogens, such as arsenic.

DNA repair gene polymorphisms and chromosomal aberrations in healthy, nonsmoking population

Nonspecific structural chromosomal aberrations (CAs) can be found at around 1% of circulating lymphocytes from healthy individuals but the frequency may be higher after exposure to carcinogenic chemicals or radiation. The frequency of CAs has been measured in occupational monitoring and an increased frequency of CAs has also been associated with cancer risk. Alterations in DNA damage repair and telomere maintenance are thought to contribute to the formation of CAs, which include chromosome type of aberrations and chromatid type of aberrations. In the present study, we used the result of our published genome-wide association studies to extract data on 153 DNA repair genes from 866 nonsmoking persons who had no known occupational exposure to genotoxic substances. Considering an arbitrary cut-off level of P< 5 × 10^-3, single nucleotide polymorphisms (SNPs) tagging 22 DNA repair genes were significantly associated with CAs and they remained significant at P < 0.05 when adjustment for multiple comparisons was done by the Binomial Sequential Goodness of Fit test. Nucleotide excision repair pathway genes showed most associations with 6 genes. Among the associated genes were several in which mutations manifest CA phenotype, including Fanconi anemia, WRN, BLM and genes that are important in maintaining genome stability, as well as PARP2 and mismatch repair genes. RPA2 and RPA3 may participate in telomere maintenance through the synthesis of the C strand of telomeres. Errors in NHEJ1 function may lead to translocations. The present results show associations with some genes with known CA phenotype and suggest other pathways with mechanistic rationale for the formation of CAs in healthy nonsmoking population.

DNA Repair Gene Polymorphisms and Chromosomal Aberrations in Exposed Populations

DNA damage and unrepaired or insufficiently repaired DNA double-strand breaks as well as telomere shortening contribute to the formation of structural chromosomal aberrations (CAs). Non-specific CAs have been used in the monitoring of individuals exposed to potential carcinogenic chemicals and radiation. The frequency of CAs in peripheral blood lymphocytes (PBLs) has been associated with cancer risk and the association has also been found in incident cancer patients. CAs include chromosome-type aberrations (CSAs) and chromatid-type aberrations (CTAs) and their sum CAtot. In the present study, we used data from our published genome-wide association studies (GWASs) and extracted the results for 153 DNA repair genes for 607 persons who had occupational exposure to diverse harmful substances/radiation and/or personal exposure to tobacco smoking. The analyses were conducted using linear and logistic regression models to study the association of DNA repair gene polymorphisms with CAs. Considering an arbitrary cutoff level of 5 × 10^-3, 14 loci passed the threshold, and included 7 repair pathways for CTA, 4 for CSA, and 3 for CAtot; 10 SNPs were eQTLs influencing the expression of the target repair gene. For the base excision repair pathway, the implicated genes PARP1 and PARP2 encode poly(ADP-ribosyl) transferases with multiple regulatory functions. PARP1 and PARP2 have an important role in maintaining genome stability through diverse mechanisms. Other candidate genes with known roles for CSAs included GTF2H (general transcription factor IIH subunits 4 and 5), Fanconi anemia pathway genes, and PMS2, a mismatch repair gene. The present results suggest pathways with mechanistic rationale for the formation of CAs and emphasize the need to further develop techniques for measuring individual sensitivity to genotoxic exposure.

An optimized comet-based in vitro DNA repair assay to assess base and nucleotide excision repair activity

This optimized protocol (including links to instruction videos) describes a comet-based in vitro DNA repair assay that is relatively simple, versatile, and inexpensive, enabling the detection of base and nucleotide excision repair activity. Protein extracts from samples are incubated with agarose-embedded substrate nucleoids ('naked' supercoiled DNA) containing specifically induced DNA lesions (e.g., resulting from oxidation, UVC radiation or benzo[a]pyrene-diol epoxide treatment). DNA incisions produced during the incubation reaction are quantified as strand breaks after electrophoresis, reflecting the extract's incision activity. The method has been applied in cell culture model systems, human biomonitoring and clinical investigations, and animal studies, using isolated blood cells and various solid tissues. Once extracts and substrates are prepared, the assay can be completed within 2 d.

GSTM3 Function and Polymorphism in Cancer: Emerging but Promising

Cancer is a major cause of human mortality; however, the molecular mechanisms and proteomic biomarkers that cause tumor progression in malignant tumors are either unknown or only partially revealed. Glutathione S-transferases mu3 (GSTM3), which belongs to a family of xenobiotic detoxifying phase II enzymes, is associated with carcinogen detoxification and the metabolism of exogenous electrophilic substances. It has been reported that GSTM3 has different polymorphisms in various tumor cells and regulates tumorigenesis, cell invasion, metastasis, chemoresistance, and oxidative stress. Deep research into the regulatory mechanisms involved in disorders of GSTM3 expression and the function of GSTM3 in different cancers may facilitate improvements in cancer prevention and targeted therapy. The combination of GSTM3 with other family members can regulate the carcinogenesis and susceptibility to different cancers in humans. GSTM3 also regulates the reactive oxygen species (ROS) and participates in oxidative stress-mediated pathology. Here, we provide a general introduction to GSTM3 in order to better understand the role of GSTM3 in cancer.

Influence of functional variants Asp312Asn and Lys751Gln of Xeroderma Pigmentosum Group D (XPD) and Glutathione S-transferase Mu 1 (GSTM1) and Theta 1 (GSTT1) genes on cutaneous melanoma susceptibility and prognosis

We aimed to evaluate whether variants in repair (XPD Asp312Asn, XPD Lys751Gln) and detoxification (GSTM1, GSTT1) genes alter risk, clinicopathological aspects and survival of cutaneous melanoma (CM). Genotyping was performed in 229 CM patients and 258 controls. Individuals with XPD 312Asp/Asn or Asn/Asn plus GSTT1 null genotype were under 2.00 (95% CI: 1.06-3.79), and XPD 312Asn/Gln haplotype was under 1.44-fold (95% CI: 0.99-2.08) increased risks to CM than others. Individuals with GSTM1 plus GSTT1 null genotype had 9.61-fold (95% CI: 2.28-40.38) increased risk of metastatic CM. At 60 months of follow-up, patients with XPD 751Gln/Gln plus GSTT1 null and GSTM1 null plus GSTT1 null genotype presented 7.36 and 3.05 more chances of evolving to death in multivariate Cox analysis, respectively. In conclusion, our data indicate, for the first time, that specific variant combinations of XPD, GSTM1 and GSTT1 may increase susceptibility to CM and influence patients' clinicopathological features and survival.

Glutathione S-Transferase Mu-3 Predicts a Better Prognosis and Inhibits Malignant Behavior and Glycolysis in Pancreatic Cancer

Background: Pancreatic cancer (PC) is a lethal malignancy with an extremely unfavorable 5-year survival rate and a high mortality rate. Glutathione S-transferase mu-3 (GSTM3) has been shown to exert different functions in the progression and development of various cancers, except for PC. This study aimed to explore the role of GSTM3 in the malignant behavior and metabolic aspects of PC, its clinical significance, and its possible molecular mechanism in pancreatic cancer.

Methods: Tumor microarrays of pancreatic ductal adenocarcinoma (PDAC) were used to evaluate the clinicopathological variables and GSTM3 expression by immunohistochemical staining. Kaplan–Meier survival and Cox regression analyses were further performed to assess the prognosis. The effect of GSTM3 on PC aggressiveness was detected using overexpressing and silencing transfection methods. Western blot, RT-qPCR, CCK-8, and cell cycle assay were applied to evaluate the expression level and proliferation. A xenograft animal model was assessed. Reactive oxygen species (ROS) were measured using the laser confocal scanner and glycolysis was detected using an Agilent Seahorse kit. RNA sequencing was used to assess the underlying mechanism and the signaling pathway involved.

Results: GSTM3 was relatively poorly expressed in PDAC tissues compared to para-tumoral tissues and a high level of GSTM3 indicated good overall survival. Functionally, overexpression of GSTM3 could significantly inhibit cell proliferation by delaying the G0/G1 transition, whereas the opposite results were found in the GSTM3 downregulation group. In addition, xenograft animal models further confirmed the effect on proliferation. Moreover, silencing of GSTM3 induced ROS accumulation and promoted glycolysis in PC, indicating its tumor suppressive effect, and vice versa when GSTM3 was upregulated. Finally, RNA sequencing results demonstrated that GSTM3 facilitates anti-tumorigenicity partly via the JAK-STAT signaling pathway in PC.

Conclusion: GSTM3 inhibited tumor progression and altered the metabolic pattern in PC. This may be a potential predictive biomarker in PC and a prospective therapeutic target.

Polymorphism in GSTM1 and GSTT1 genes influence DNA damage in personnel occupationally exposed to volatile anaesthetics (VA), from Peshawar, Pakistan

Objectives

The objective of this study was to assess the influence of antioxidant gene GSTM1 and GSTT1 on DNA damage in personnel occupationally exposed to volatile anaesthetics (VA).

Methods

The study groups were composed of 50 exposed subjects (anaesthesia workers) and 49 controls. Blood samples were collected from both subjects. DNA damage was analysed through the comet assay technique. Biomarker genes GSTM1 and GSTT1 were inspected through PCR technique for polymorphism.

Results

The comet assay technique showed that the Total Comet Score (TCS) in exposed subjects was significantly higher (p=0.0001) than the control. Age and smoking had significant effects on TCS in the study groups (p<0.05). Duration of occupational exposure had significant positive correlation (r=0.755, p<0.001) with DNA damage. The null polymorphism in GSTM1 and GSTT1 gene showed a significant effect (p<0.001 and p<0.000) on the DNA damage.

Conclusions

The polymorphism in GSTM1 and GSTT1 gene significantly damage DNA in personnel occupationally exposed to VA.

DNA damage analysis concerning GSTM1 and GSTT1 gene polymorphism in gold jewellery workers from Peshawar Pakistan

PURPOSE

To evaluate the genotoxic effects of gold jewellery fumes and its association with GSTM1 and GSTT1 genetic polymorphisms.

MATERIALS AND METHODS

We examined 94 subjects including 54 gold jewellery workers and 40 controls. The DNA damage was evaluated by alkaline comet assay and genotyping by PCR.

RESULTS

The mean total comet score (TCS) in gold jewellery workers was significantly higher as compared to the control subjects (128.0 ± 60.6 versus 47.7 ± 21.4; p = 0.0001). Duration of occupational exposure had positive correlation (r = 0.453, p < 0.01) with DNA damage. Age and tobacco use had significant effects on the TCS of the exposed group as compared to the control group (p < 0.05). The frequency of the GSTM1-null genotype in the exposed group was significant (p = 0.004) as compared to the control group. No significant association (p > 0.05) between the GSTM1 and GSTT1 genotypes and DNA damage was found.

CONCLUSIONS

Our results suggest that there is increased DNA damage in gold jewellery workers due to their occupational surroundings. Hence there is a strong need to educate the workers about the adverse health effects of potentially hazardous chemicals and highlight the importance of using protective measures.

Genoprotective activities of plant natural substances in cancer and chemopreventive strategies in the context of 3P medicine

Severe durable changes may occur to the DNA structure caused by exogenous and endogenous risk factors initiating the process of carcinogenesis. By evidence, a large portion of malignancies have been demonstrated as being preventable. Moreover, the targeted prevention of cancer onset is possible, due to unique properties of plant bioactive compounds. Although genoprotective effects of phytochemicals have been well documented, there is an evident lack of articles which would systematically present the spectrum of anticancer effects by phytochemicals, plant extracts, and plant-derived diet applicable to stratified patient groups at the level of targeted primary (cancer development) and secondary (cancer progression and metastatic disease) prevention. Consequently, clinical implementation of knowledge accumulated in the area is still highly restricted. To stimulate coherent co-development of the dedicated plant bioactive compound investigation on one hand and comprehensive cancer preventive strategies on the other hand, the current paper highlights and deeply analyses relevant evidence available in the area. Key molecular mechanisms are presented to detail genoprotective and anticancer activities of plants and phytochemicals. Clinical implementation is discussed. Based on the presented evidence, advanced chemopreventive strategies in the context of 3P medicine are considered.

Distinct pathways associated with chromosomal aberration frequency in a cohort exposed to genotoxic compounds compared to general population

Non-specific structural chromosomal aberrations (CAs) observed in peripheral blood lymphocytes of healthy individuals can be either chromosome-type aberrations (CSAs) or chromatid-type aberrations (CTAs) depending on the stage of cell division they are induced in and mechanism of formation. It is important to study the genetic basis of chromosomal instability as it is a marker of genotoxic exposure and a predictor of cancer risk. For that purpose, we conducted two genome-wide association studies (GWASs) on healthy individuals in the presence and absence of apparent genotoxic exposure from the Czech Republic and Slovakia. The pre-GWAS cytogenetic analysis reported the frequencies of CSA, CTA and total CA (CAtot). We performed both linear and binary logistic regression analysis with an arbitrary cut-off point of 2% for CAtot and 1% for CSA and CTA. Using the statistical threshold of 1.0 × 10-5, we identified five loci with in silico predicted functionality in the reference group and four loci in the exposed group, with no overlap between the associated regions. A meta-analysis on the two GWASs identified further four loci with moderate associations in each of the studies. From the reference group mainly loci within genes related to DNA damage response/repair were identified. Other loci identified from both the reference and exposed groups were found to be involved in the segregation of chromosomes and chromatin modification. Some of the discovered regions in each group were implicated in tumourigenesis and autism.

Influence of glutathione S-transferases (GSTM1, GSTT1, and GSTP1) genetic polymorphisms and smoking on susceptibility risk of chronic myeloid leukemia and treatment response

Background

Glutathione S‐transferases (GSTs) polymorphisms may impact on chronic myeloid leukemia (CML) risk or heterogeneous responses to Imatinib mesylate (IM). The aim of this study was to evaluate the correlation between GSTs polymorphisms and CML risk, treatment response.

Methods

We genotyped GSTM1, GSTT1 null deletion polymorphisms, and GSTP1 Ile105Val polymorphism by PCR methods and BCR‐ABL transcripts were analyzed by qRT‐PCR in 104 CML patients and 104 sex‐ and age‐matched healthy individuals.

Results

Individual analysis showed significant association of GSTM1 (p = 0.008; OR = 0.46; 95% CI: 0.26–0.82) and GSTP1 genes (p = 0.04; OR = 1.56; 95% CI: 1.016–2.423) with CML risk. The combined analysis indicated that GSTM1 null/GSTT1 present, GSTM1‐null/GSTP1M*(AG/GG) as well as GSTT1 present/ GSTP1M* genotype were associated with CML risk (ORg(‐):2.28; 95% CI: 1.29–4.04; ORgg: 2.85; 95% CI: 1.36–5.97; OR(‐)g: 1.75; 95% CI: 0.99–3.06, respectively). The proportion of CML cancer attributable to the interaction of smoking and GSTM1 null, GSTT1null, and GSTP1 M* was 42%, 39%, and 13%, respectively. Patients with GSTM1‐null and GSTP1 AG/GG genotype had significantly a lower rate of MMR achievement (p = 0.00; p = 0.009 respectively). Event‐free survival (EFS) percentage was similar between GSTM1 null and GSTM1 present patients (p = 0.21).

Conclusion

Our study suggests the influence of GSTM1 and GSTP1 polymorphisms on CML risk and treatment response. The interaction between GSTs polymorphisms and smoking plays a significant role on CML susceptibility.

Antioxidant Defenses Confer Resistance to High Dose Melphalan in Multiple Myeloma Cells

Background: Multiple myeloma (MM) is the second most common hematological cancer after lymphoma. It is characterized by the accumulation of clonal malignant plasma cells within the bone marrow. The development of drug resistance remains a major problem for effective treatment of MM. Understand the mechanisms underlying drug resistance in MM is a focal point to improve MM treatment. Methods: In the current study, we analyzed further the role of redox imbalance induction in melphalan-induced toxicity both in human myeloma cell lines (HMCLs) and primary myeloma cells from patients. Results: We developed an in-vitro model of short-term resistance to high-dose melphalan and identified that pretreatment with physiological concentration of GSH protects HMCLs from melphalan-induced cell cycle arrest and cytotoxicity. We validated these results using primary MM cells from patients co-cultured with their bone marrow microenvironment. GSH did not affect the ability of melphalan to induce DNA damages in MM cells. Interestingly, melphalan induced reactive oxygen species, a significant decrease in GSH concentration, protein and lipd oxydation together with NRF2 (NF-E2-related factor 2) pathway activation. Conclusions: Our data demonstrate that antioxidant defenses confers resistance to high dose melphalan in MM cells, supporting that redox status in MM cells could be determinant for patients’ response to melphalan.

Polymorphisms of the DNA repair gene EXO1 modulate cognitive aging in old adults in a Taiwanese population

Evidence indicates that the age-related neuropathological mechanisms associated with DNA repair genes may contribute to cognitive aging and Alzheimer's disease. In this study, we hypothesize that single nucleotide polymorphisms (SNPs) within 155 DNA repair genes may be linked to cognitive aging independently and/or through complex interactions in an older Taiwanese population. A total of 3,730 Taiwanese subjects aged over 60 years from the Taiwan Biobank were analyzed. Mini-Mental State Examination (MMSE) was administered to all subjects, and MMSE scores were used to measure cognitive functions. Our data showed that out of 1,652 SNPs, the rs1776181 (P = 1.47 × 10^-5), rs1776177 (P = 8.42 × 10^-7), rs1635510 (P = 7.97 × 10^-6), and rs2526698 (P = 7.06 × 10^-6) SNPs in the EXO1 gene were associated with cognitive aging. The association with these SNP remained significant after performing Bonferroni correction. Additionally, we found that interactions between the EXO1 and RAD51C genes influenced cognitive aging (P = 0.002). Finally, we pinpointed the influence of interactions between EXO1 and physical activity (P < 0.001) as well as between DCLRE1C and physical activity (P < 0.001). Our study indicated that DNA repair genes may contribute to susceptibility in cognitive aging independently as well as through gene-gene and gene-physical interactions.

Genetic variation associated with chromosomal aberration frequency: A genome-wide association study

Chromosomal aberrations (CAs) in human peripheral blood lymphocytes (PBL) measured with the conventional cytogenetic assay have been used for human biomonitoring of genotoxic exposure for decades. CA frequency in peripheral blood is a marker of cancer susceptibility. Previous studies have shown associations between genetic variants in metabolic pathway, DNA repair and major mitotic checkpoint genes and CAs. We conducted a genome-wide association study on 576 individuals from the Czech Republic and Slovakia followed by a replication in two different sample sets of 482 (replication 1) and 1288 (replication 2) samples. To have a broad look at the genetic susceptibility associated with CA frequency, the sample sets composed of individuals either differentially exposed to smoking, occupational/environmental hazards, or they were untreated cancer patients. Phenotypes were divided into chromosome- and chromatid-type aberrations (CSAs and CTAs, respectively) and total chromosomal aberrations (CAtot). The arbitrary cutoff point between individuals with high and low CA frequency was 2% for CAtot and 1% for CSA and CTA. The data were analyzed using age, sex, occupation/cancer and smoking history as covariates. Altogether 11 loci reached the P-value of 10^-5 in the GWAS. Replication 1 supported the association of rs1383997 (8q13.3) and rs2824215 (21q21.1) in CAtot and rs983889 (5p15.1) in CTA analysis. These loci were found to be associated with genes involved in mitosis, response to environmental and chemical factors and genes involved in syndromes linked to chromosomal abnormalities. Identification of new genetic variants for the frequency of CAs offers prediction tools for cancer risk in future. Environ. Mol. Mutagen. 60:17-28, 2019. © 2018 Wiley Periodicals, Inc.

A novel functional polymorphism of GSTM3 reduces clear cell renal cell carcinoma risk through enhancing its expression by interfering miR-556 binding

Dysregulation of glutathione‐S‐transferase M3 (GSTM3) has been related to clear cell renal cell carcinoma (ccRCC) in our former study. GSTM3 plays a pivotal role of detoxification and clearance of reactive oxygen species (ROS) in tumour tissues. This study aimed to examine: (1) the associations between GSTM3 single nucleotide polymorphisms (SNPs) and risk of ccRCC, and (2) the potential molecular mechanism accounting for its effects. 5 SNPs in 3′UTR of GSTM3 were initially genotyped in 329 cases and 420 healthy controls. A SNP‐rs1055259 was found to be significantly associated with the susceptibility of ccRCC (OR = 0.59, 95% CI = 0.41‐0.92; P = .019). The minor allele of rs1055259 (G allele) was associated with RCC risk. This SNP was predicted to affect microRNA (miR)‐556 binding to 3′UTR of GSTM3 mRNA. To determine the functional impact, plasmid constructs carrying different alleles of rs1055259 were created. Compared to rs1055259 A‐allele constructs, cells transfected with rs1055259 G‐allele construct had higher transcriptional activity and were less responsive to miR‐556 changes and gene expression. Elevated GSTM3 expression in G‐allele cells was associated with ROS activity and ccRCC development. Taken together, this study indicated that a functional polymorphism of GSTM3 ‐rs1055259 reduced susceptibility of RCC in the Chinese population. It influenced GSTM3 protein synthesis by interfering miR‐556 binding, subsequently suppressed ROS activity and ccRCC progression.

Combined effects of glutathione S-transferase M1 and T1 polymorphisms on risk of lung cancer: Evidence from a meta-analysis

Many studies have reported an association between the glutathione S-transferase M1 null and T1 null polymorphisms and lung cancer risk. However, the combined effects of GSTM1 null and GSTT1 null polymorphisms have not been reported previously. We, therefore, performed a meta-analysis to investigate the combined effects. 40 publications with 44 case–control studies were selected in the meta-analysis, including 13,706 cases and 13,093 controls. Significant association was observed between the combined effects of GSTM1 and GSTT1 polymorphisms and lung cancer risk when all the eligible studies were pooled into the meta-analysis. When we performed subgroup analysis, significantly increased lung cancer risk was observed in Caucasians (− − vs. + +: OR = 1.23, 95% CI: 1.07 to 1.41), Asians (− − vs.− +: OR = 1.24, 95% CI: 1.10 to 1.41; recessive model: OR = 1.45, 95% CI: 1.19 to 1.77; dominant model: OR = 1.53, 95% CI: 1.24 to 1.90), Indians (− − vs. + +: OR = 2.53, 95% CI: 1.61 to 3.98; recessive model: OR = 1.69, 95% CI: 1.07 to 2.67; dominant model: OR = 2.11, 95% CI: 1.36 to 3.28), hospital-based studies, and population-based studies. In summary, this meta-analysis indicates that the combined effects of the GSTM1 and GSTT1 polymorphisms are associated with increased lung cancer risk in Asians, Caucasians, and Indians.

Impact of SNP-SNP interactions of DNA repair gene ERCC5 and metabolic gene GSTP1 on gastric cancer/atrophic gastritis risk in a Chinese population

AIM

To investigate the interactions of the DNA repair gene excision repair cross complementing group 5 (ERCC5) and the metabolic gene glutathione S-transferase pi 1 (GSTP1) and their effects on atrophic gastritis (AG) and gastric cancer (GC) risk.

METHODS

Seven ERCC5 single nucleotide polymorphisms (SNPs) (rs1047768, rs2094258, rs2228959, rs4150291, rs4150383, rs751402, and rs873601) and GSTP1 SNP rs1695 were detected using the Sequenom MassARRAY platform in 450 GC patients, 634 AG cases, and 621 healthy control subjects in a Chinese population.

RESULTS

Two pairwise combinations (ERCC5 rs2094258 and rs873601 with GSTP1 rs1695) influenced AG risk (P_interaction = 0.008 and 0.043, respectively), and the ERCC5 rs2094258-GSTP1 rs1695 SNP pair demonstrated an antagonistic effect, while ERCC5 rs873601-GSTP1 rs1695 showed a synergistic effect on AG risk OR = 0.51 and 1.79, respectively). No pairwise combinations were observed in relation to GC risk. There were no cumulative effects among the pairwise interactions (ERCC5 rs2094258 and rs873601 with GSTP1 rs1695) on AG susceptibility (P_trend > 0.05). When the modification effect of Helicobacter pylori (H. pylori) infection was evaluated, the cumulative effect of one of the aforementioned pairwise interactions (ERCC5 rs873601-GSTP1 rs1695) was associated with an increased AG risk in the case of negative H. pylori status (P_trend = 0.043).

CONCLUSION

There is a multifarious interaction between the DNA repair gene ERCC5 SNPs (rs2094258 and rs873601) and the metabolic gene GSTP1 rs1695, which may form the basis for various inter-individual susceptibilities to AG.

Polymorphisms of GSTM1, GSTT1, GSTP1 genes and chromosomal aberrations in lung cancer patients

PURPOSE

To study the potential links between genetic polymorphisms in the GSTT1, GSTM1, GSTP1 genes and the frequency of chromosomal aberrations (CAs) in lung cancer patients and healthy residents in Russian Federation.

METHODS

200 cells in well-spread metaphase with 46 chromosomes were examined for 353 newly diagnosed lung cancer patients (males) who received medical treatment in the Kemerovo Regional Oncology Center (Kemerovo, Russian Federation), and 300 healthy males from Kemerovo, Russian Federation. The polymorphisms of the GSTM1 del and GSTT1 del genes were analysed by multiplex PCR. Genotyping of the polymorphic variants in the GSTP1 (A313G, T341C) gene was performed using Real-time PCR with competing TaqMan probes complementary to the polymorphic DNA sites. The data analysis was performed using software STATISTICA 8.0 (StatSoft Inc., USA).

RESULTS

We discovered that a GSTM1 del polymorphism increases the frequency of chromosomal damage in smoking patients with lung cancer, a general group of lung cancer patients, donors with non-small cell lung cancer and patients in the latest stages of the malignant process. The synergetic effects of occupational exposure and the malignant process can induce some modifications in the cytogenetic status in lung cancer patients harbouring the GSTM1 del polymorphism.

CONCLUSIONS

CAs in peripheral blood lymphocytes can be used as biomarkers of the early biological effects of exposure to genotoxic carcinogens and may predict future cancer incidence in several epidemiologic studies. Genetic changes in genes encoding phase II detoxification enzymes are linked to decreases in the metabolic detoxification of environmentally derived genotoxic carcinogens.

GSTM1 and GSTP1, but not GSTT1 genetic polymorphisms are associated with chronic myeloid leukemia risk and treatment response

BACKGROUND

Chronic myeloid leukemia (CML) is associated to the BCR-ABL1 oncogene and can successfully be treated with tyrosine kinase inhibitors (TKIs). However, it remains still under investigation which molecular factors may influence CML risk or varying responses to TKIs. The aim of this study was to assess the role of Glutathione-S-transferases (GSTs) genetic polymorphisms in CML susceptibility and TKI clinical outcome.

MATERIALS

Deletion polymorphisms in GSTM1 and GSTT1 genes and the single nucleotide polymorphism in GSTP1 c.319A>G (rs1695; p.105Ile>Val) were genotyped by PCR methods in 141 CML treated patients and 141 sex- and age-matched healthy individuals.

RESULTS

Individual analysis of each GST gene showed no association with CML risk. A trend toward significance (p=0.07) for a recessive model was found for GSTP1 (OR: 2.04; CI: 0.94-4.4). However, the combined analysis showed that GSTM1-null/GSTP1-GG as well as GSTT1-null/GSTP1-GG were associated with CML development (p=0.03; OR: 3.54 CI: 1.2-14.57; p=0.05; OR: 12.65; CI: 1.17-21.5). The relationship with treatment outcome showed that the presence of GSTM1 gene was significantly linked with an inferior rate of major molecular response (p=0.048) and poor event free-survival (EFS) (p=0.02). Furthermore, a group of patients with GSTP1-GG genotype were significantly associated with reduced EFS comparing to those carrying other GSTP1 genotypes (p=0.049). GSTP1-GG genotypes had short time to treatment failure in a group of patients unresponsive to TKIs comparing to other GSTP1 genotypes (p=0.03).

CONCLUSIONS

This study highlights the significance of GSTM1 and GSTP1 polymorphisms on CML susceptibility and response to TKIs in the Argentinean population.

Modulatory role of GSTM1 null genotype on the frequency of micronuclei in pesticide-exposed agricultural workers

In this study, we aimed to investigate the extent of genotoxic risk and the association between null GSTM1/GSTT1 and GSTP1 Ile105Val variants and cellular DNA damage, as measured by micronucleus (MN) assay in a group of agricultural workers from Denizli, Turkey. Peripheral blood samples were collected from 116 subjects, including 58 workers who were occupationally exposed to pesticides and 58 healthy unexposed controls. The MN frequencies of each individual were assessed by cytokinesis-blocked micronuclei assays on lymphocytes. Genotypes for different GST variants were determined using polymerase chain reaction-based methods. A significant 3.4-fold increase in MN frequency was observed in workers compared with the controls ( p < 0.001). Among the GST genotypes, only the GSTM1 null genotype was found to be significantly associated with an increased MN frequency in workers ( p = 0.01). Individuals with a concomitant null GSTM1/GSTT1 genotype demonstrated a significant ( p = 0.01) increase in MN frequency compared with those with functional isozymes in the exposed worker group. The association of the GSTM1 null genotype with higher MN frequency suggests that it may be a modifier of genotoxic risk in individuals exposed to pesticides and may thus be a candidate susceptibility biomarker for human biomonitoring studies.

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.

A novel reductive amination method with isotopic formaldehydes for the preparation of internal standard and standards for determining organosulfur compounds in garlic

Garlic (Allium sativum) is a long-cultivated plant that is widely utilized in cooking and has been employed as a medicine for over 4000 years. In this study, we fabricated standards and internal standards (ISs) for absolute quantification via reductive amination with isotopic formaldehydes. Garlic has four abundant organosulfur compounds (OSCs): S-allylcysteine, S-allylcysteinine sulfoxide, S-methylcysteine, and S-ethylcysteine are abundant in garlic. OSCs with primary amine groups were reacted with isotopic formaldehydes to synthesize ISs and standards. Cooked and uncooked garlic samples were compared, and we utilized tandem mass spectrometry equipped with a selective reaction monitoring technique to absolutely quantify the four organosulfur compounds.

XPC (A2920C), XPF (T30028C), TP53 (Arg72Pro), and GSTP1 (Ile105Val) polymorphisms in prognosis of cutaneous melanoma

This study aimed to evaluate whether XPC A2920C, XPF T30028C, TP53 Arg72Pro, and GSTP1 Ile105Val polymorphisms alter outcomes of cutaneous melanoma (CM) patients. DNA from 237 CM patients seen at the University of Campinas Teaching Hospital from April 2000 to February 2014 was analyzed by polymerase chain reaction and restriction fragment length polymorphism assays. The prognostic impact of genotypes of polymorphisms on progression-free survival (PFS) and overall survival (OS) of CM patients were examined using the Kaplan-Meier probability estimates and univariate and multivariate Cox regression analyses. At 60 months of follow-up, shorter PFS and OS were seen in patients with XPF CC genotype (48.9 vs. 66.7 %, P = 0.002; 77.9 vs. 83.5 %, P = 0.006, respectively) and XPF CC + TP53 ArgArg (43.6 vs. 65.9 %, P = 0.007; 71.6 vs. 84.8 %, P = 0.006, respectively) compared with those with remaining genotypes (Kaplan-Meier estimates). Patients with XPF CC (hazard ratio (HR) 2.45, P = 0.002; HR 3.77, P = 0.005) and XPF CC + TP53 ArgArg (HR 2.67, P = 0.009; HR 4.04, P = 0.03) genotypes had more chance to present tumor progression in univariate and multivariate analyses, whereas patients with XPF CC (HR 2.78, P = 0.009) and XPF CC + TP53 ArgArg (HR 3.84, P = 0.01) genotypes were under greater risk of progressing to death in univariate analysis, compared with those with the remaining genotypes. The data suggest, for the first time, that inherited abnormalities in DNA repair pathway related to XPF 30028C and TP53 Arg72Pro polymorphisms act as prognostic factors for PFS and OS of CM patients.

Polymorphisms in oxidative stress-related genes are associated with nasopharyngeal carcinoma susceptibility

Nasopharyngeal carcinoma (NPC) is a complex multifactorial disorder involving both genetic and environmental factors. Polymorphisms of genes encoding nitric oxide synthase (NOS) and antioxidant glutathione-S transferases (GSTs) have been associated with various tumors. We examined the combined role of NOS3, NOS2 and GST polymorphisms in NPC risk in Tunisians. We found that NOS3−786C allele and −786 CC genotype, NOS3+894T allele and +894 GT+TT genotypes, NOS2−277 G allele and −277 GG genotype, and GSTT1 del/del genotype, are more prevalent in NPC patients as compared to healthy controls. Our results suggest that genetically driven dysfunction in red–ox stress pathway could augment the risk in NPC-susceptible individuals.

Polymorphic variants of GSTM1, GSTT1, and GSTP1 genes in childhood acute leukemias: A preliminary study in Argentina

BACKGROUND AND AIM

Despite recent major advances in leukemia research, the etiopathogenesis of childhood leukemias remains far elusive. Individual predisposing factors, including polymorphisms in detoxification enzymes, have been implicated in the molecular pathogenesis and heterogeneity of the disease. Genetic polymorphisms of glutathione S-transferases (GSTs) that alter enzyme activity could be an additional factor that increases the risk of acute leukemia, but data are lacking in Argentina. We assessed the association of GST polymorphisms and the susceptibility to childhood leukemia in Argentina by conducting an exploratory case-control study and correlated patients' genotype to clinical and biological features.

METHODS

Deletion polymorphisms in GSTM1 and GSTT1 genes and the single nucleotide polymorphism in GSTP1 c.313A>G (rs1695; p.105Ile>Val) were genotyped by PCR-RFLP in 36 patients and 133 healthy individuals.

RESULTS

GSTM1-null genotype was associated with a lower risk of developing acute leukemia (P = 0.013; OR: 0.31; CI: 0.12-0.80), while GSTP1-GG variants displayed an increased risk (P = 0.01; OR: 3.9; CI: 1.85-8.2). However, no differences were found for GSTT1 gene. Conclusion These preliminary results, to be validated in a larger population from Argentina, suggest that the development of pediatric leukemia may be differentially influenced by polymorphic variants in GST genes.

Effects of GSTM1/GSTT1 gene polymorphism and fruit & vegetable consumption on antioxidant biomarkers and cognitive function in the elderly: a community based cross-sectional study

Background

It was reported that Glutathione S-transferase (GST) gene polymorphism and fruit and vegetable (FV) intake were associated with body antioxidant capacity. The oxidative/anti-oxidative imbalance played an important role in the pathogenesis of AD. However, the association of GST genotype, dietary FV consumption with body antioxidant biomarkers and cognitive function in the elderly is not clear.

Objective

The aim of the present study was to determine the association of GST genotype, and dietary FV intake, with antioxidant biomarkers and cognitive function in the elderly.

Methods

Food frequency questionnaire was used to collect data of dietary FV intakes in 504 community dwelling elderly aged from 55 to 75 years old. GSTM1 and GSTT1 genotypes were determined by using multiple-PCR method. Plasma and erythrocyte antioxidant biomarkers were measured. Cognitive function was measured by using Montreal Cognitive Assessment. Statistical analysis was applied for exploring the association of GST genotype and FV intake with antioxidant biomarkers level and cognitive function in the elderly.

Results

Individual GSTM1 or GSTT1 gene deletion affects body antioxidant biomarkers levels, including erythrocyte GST activity, plasma total antioxidant capacity, and glutathione levels. GSTM1and/or GSTT1 gene deletion have no effects on cognitive function in the surveyed participants. The effect of GST genotype on antioxidant biomarkers are FV intake dependent. There is interaction of FV intake and GST genotype on cognitive function in the elderly.

Conclusion

GST genotype or daily FV consumption impact body antioxidant biomarkers, but not cognitive function in the elderly. There were combined effects of GST genotype and FV consumption on cognitive function in the elderly population. Large scale perspective population study is required to explore the association of GST genetic polymorphism, FV consumption and antioxidant biomarkers and cognitive function in the elderly.

GSTT1 polymorphism and the risk of developing prostate cancer

A possible association between glutathione S-transferase theta 1 gene (GSTT1) polymorphism and the risk of developing prostate cancer is currently hotly debated, but evidence from various epidemiologic studies remains unclear. This investigation was performed to assess whether an association between GSTT1 polymorphism and prostate cancer risk exists by using meta-analysis to combine comparable studies, thereby increasing sample size and statistical significance, as well as to identify patterns in various studies. The association reports were identified from the PubMed database and the Cochrane Library on March 1, 2013, and data from eligible studies (from 1999-2012) were synthesized. Thirty-eight reports were included in this meta-analysis on the association of the null genotype of GSTT1 with prostate cancer risk. No solid association between the GSTT1 null genotype and prostate cancer risk could be established for the overall population (odds ratio = 1.11, 95% confidence interval: 0.97, 1.27; P = 0.13). However, the GSTT1 null genotype was distinctly associated with prostate cancer risk in Caucasians (odds ratio = 1.24, 95% confidence interval: 1.03, 1.48, P = 0.02). In conclusion, the GSTT1 null genotype is associated with prostate cancer risk in Caucasians, but not in the overall population.

Glutathione S-transferase gene polymorphisms in celiac disease and their correlation with genomic instability phenotype

BACKGROUND AND OBJECTIVE

Genomic instability and reduced glutathione S-transferase (GST) activity have been identified as potential risk factors for malignant complications in celiac disease (CD). In this study, we assessed the possible influence of GST polymorphisms on genome instability phenotypes in a genetically characterised group of celiac patients from previous studies.

METHODS

The deletion polymorphisms in GSTM1 and GSTT1 genes and the single-nucleotide polymorphism GSTP1 c.313A>G were genotyped using PCR in a set of 20 untreated adult patients with a known genomic instability phenotype and 69 age- and sex-matched healthy individuals.

RESULTS

The frequencies of variant genotypes in patients were GSTM1-null (30%), GSTT1-null (5%), GSTP1-AG (60%) and GSTP1-GG (15%), and they showed no differences from controls. No significant differences were found in the genotype distribution based on telomere length. Cases with GSTM1-null genotype (83%) and microsatellite stability were more frequent than those with genomic instability. Moreover, carriers of GSTP1-variant genotype (73%) and stable phenotype were significantly increased compared to unstable patients (27%) (P=0.031). No differences were found according to the clinical-pathological characteristics of celiac cases.

CONCLUSIONS

No association between GST polymorphic variants and celiac-associated genomic instability was proven in our cohort. Future studies should explore the usefulness of other biomarkers to distinguish celiac patients who are susceptible to cancer development.

Glutathione S-transferase Mu 2-transduced mesenchymal stem cells ameliorated anti-glomerular basement membrane antibody-induced glomerulonephritis by inhibiting oxidation and inflammation

INTRODUCTION

Oxidative stress is implicated in tissue inflammation, and plays an important role in the pathogenesis of immune-mediated nephritis. Using the anti-glomerular basement membrane antibody-induced glomerulonephritis (anti-GBM-GN) mouse model, we found that increased expression of glutathione S-transferase Mu 2 (GSTM2) was related to reduced renal damage caused by anti-GBM antibodies. Furthermore, mesenchymal stem cell (MSC)-based therapy has shed light on the treatment of immune-mediated kidney diseases. The aim of this study was to investigate if MSCs could be utilized as vehicles to deliver the GSTM2 gene product into the kidney and to evaluate its potential therapeutic effect on anti-GBM-GN.

METHODS

The human GSTM2 gene (hGSTM2) was transduced into mouse bone marrow-derived MSCs via a lentivirus vector to create a stable cell line (hGSTM2-MSC). The cultured hGSTM2-MSCs were treated with 0.5 mM H2O2, and apoptotic cells were measured by terminal dUTP nick-end labeling (TUNEL) assay. The 129/svj mice, which were challenged with anti-GBM antibodies, were injected with 10⁶ hGSTM2-MSCs via the tail vein. Expression of hGSTM2 and inflammatory cytokines in the kidney was assayed by quantitative PCR and western blotting. Renal function of mice was evaluated by monitoring proteinuria and levels of blood urea nitrogen (BUN), and renal pathological changes were analyzed by histochemistry. Immunohistochemical analysis was performed to measure inflammatory cell infiltration and renal cell apoptosis.

RESULTS

MSCs transduced with hGSTM2 exhibited similar growth and differentiation properties to MSCs. hGSTM2-MSCs persistently expressed hGSTM2 and resisted H2O2-induced apoptosis. Upon injection into 129/svj mice, hGSTM2-MSCs migrated to the kidney and expressed hGSTM2. The anti-GBM-GN mice treated with hGSTM2-MSCs exhibited reduced proteinuria and BUN (58% and 59% reduction, respectively) and ameliorated renal pathological damage, compared with control mice. Mice injected with hGSTM2-MSCs showed alleviated renal inflammatory cell infiltration and reduced expression of chemokine (C-C motif) ligand 2 (CCL2), interleukin (IL)-1β and IL-6 (53%, 46% and 52% reduction, respectively), compared with controls. Moreover, hGSTM2-MSCs increased expression of renal superoxide dismutase and catalase, which may associate with detoxifying reactive oxygen species to prevent oxidative renal damage.

CONCLUSIONS

Our data suggest that the enhanced protective effect of GSTM2-transduced MSCs against anti-GBM-GN might be associated with inhibition of oxidative stress-induced renal cell apoptosis and inflammation, through over-expression of hGSTM2 in mouse kidneys.

Polymorphisms of genes involved in polycyclic aromatic hydrocarbons' biotransformation and atherosclerosis

Polycyclic aromatic hydrocarbons (PAHs) are among the most prevalent environmental pollutants and result from the incomplete combustion of hydrocarbons (coal and gasoline, fossil fuel combustion, byproducts of industrial processing, natural emission, cigarette smoking, etc.). The first phase of xenobiotic biotransformation in the PAH metabolism includes activities of cytochrome P450 from the CYP1 family and microsomal epoxide hydrolase. The products of this biotransformation are reactive oxygen species that are transformed in the second phase through the formation of conjugates with glutathione, glucuronate or sulphates. PAH exposure may lead to PAH-DNA adduct formation or induce an inflammatory atherosclerotic plaque phenotype. Several genetic polymorphisms of genes encoded for enzymes involved in PAH biotransformation have been proven to lead to the development of diseases. Enzyme CYP P450 1A1, which is encoded by the CYP1A1 gene, is vital in the monooxygenation of lipofilic substrates, while GSTM1 and GSTT1 are the most abundant isophorms that conjugate and neutralize oxygen products. Some single nucleotide polymorphisms of the CYP1A1 gene as well as the deletion polymorphisms of GSTT1 and GSTM1 may alter the final specific cellular inflammatory respond. Occupational exposure or conditions from the living environment can contribute to the production of PAH metabolites with adverse effects on human health. The aim of this study was to obtain data on biotransformation and atherosclerosis, as well as data on the gene polymorphisms involved in biotransformation, in order to better study gene expression and further elucidate the interaction between genes and the environment.

Association between glutathione S-transferase T1 null genotype and risk of lung cancer: a meta-analysis of 55 studies

The relationship between glutathione S-transferase T1 (GSTT1) gene polymorphism and the risk of lung cancer from the published reports are still conflicting. This study was conducted to evaluate the relationship between GSTT1 polymorphism and the risk of lung cancer. A comprehensive research was conducted through the databases, and 55 studies were recruited into this meta-analysis for the association of null genotype of GSTT1 with lung cancer susceptibility, consisting of 15,140 patients with lung cancer and 16,662 controls. There was a significant association between GSTT1 null genotype and lung cancer risk in the overall populations (OR = 1.138, 95% CI = 1.032-1.255, P heterogeneity = 0.000, P = 0.009). Furthermore, GSTT1 null genotype was associated with the lung cancer risk in Asians (OR = 1.469, 95% CI = 1.228-1.757, P heterogeneity = 0.000, P = 0.000). However, GSTT1 null genotype was not associated with the risk of lung cancer in Caucasians and Africans. In conclusion, GSTT1 null genotype is associated with the lung cancer in overall populations and in Asians.

Common polymorphic deletion of glutathione S-transferase theta predisposes to acquired aplastic anemia: Independent cohort and meta-analysis of 609 patients

Acquired aplastic anemia (AA) is a rare life-threatening bone marrow failure syndrome, caused by autoimmune destruction of hematopoietic stem and progenitor cells. Epidemiologic studies suggest that environmental exposures and metabolic gene polymorphisms contribute to disease pathogenesis. Several case-control studies linked homozygous deletion of the glutathione S-transferase theta (GSTT1) gene to AA; however, the role of GSTT1 deletion remains controversial as other studies failed to confirm the association. We asked whether a more precise relationship between the GSTT1 null polymorphism and aplastic anemia could be defined using a meta-analysis of 609 aplastic anemia patients, including an independent cohort of 67 patients from our institution. We searched PubMed, Embase, and the Cochrane Database for studies evaluating the association between GSTT1 null genotype and development of AA. Seven studies, involving a total of 609 patients and 3,914 controls, fulfilled the eligibility criteria. Meta-analysis revealed a significant association of GSTT1 null genotype and AA, with an OR = 1.74 (95% CI 1.31-2.31, P < 0.0001). The effect was not driven by any one individual result, nor was there evidence of significant publication bias. The association between AA and GSTT1 deletion suggests a role of glutathione-conjugation in AA, possibly through protecting the hematopoietic compartment from endogenous metabolites or environmental exposures. We propose a model whereby protein adducts generated by reactive metabolites serve as neo-epitopes to trigger autoimmunity in aplastic anemia.

A meta-analysis of the relationship between glutathione S-transferase T1 null/presence gene polymorphism and the risk of lung cancer including 31802 subjects

The relationship between glutathione S-transferase T1 (GSTT1) null/presence gene polymorphism and the risk of lung cancer from the published reports are still conflicting. This study was conducted to evaluate the relationship between GSTT1 null/presence gene polymorphism and the risk of lung cancer using meta-analysis method. The association studies were identified from PubMed, and Cochrane Library on July 1, 2012, and eligible investigations were included and synthesized using meta-analysis method. 51 reports were recruited into this meta-analysis for the association of null genotype of GSTT1 with lung cancer susceptibility, consisting of 15,140 patients with lung cancer and 16,662 controls. There was a marked association between GSTT1 null genotype and lung cancer risk in overall populations (OR = 1.15, 95 % CI 1.04-1.27, P = 0.007). Furthermore, GSTT1 null genotype was associated with the lung cancer risk in Asians (OR = 1.47, 95 % CI 1.23-1.76, P < 0.0001). However, GSTT1 null genotype was not associated with the risk of lung cancer in Caucasians, Brazilian population and Africans. In conclusion, GSTT1 null genotype is associated with the lung cancer in overall populations and in Asians.

The glutathione S-transferase T1 deletion is associated with susceptibility to multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) occurs as a result of interaction between genetic and environmental factors. Recent data support the view that oxidative damage is one of an early event in MS tissue injury. The safe elimination of reactive oxygen species and toxins via glutathione S-transferase (GST) pathways is required in order to protect cells against reactive oxygen-induced damage. The aim of our study was to analyze the possible association of GSTM1 and GSTT1 gene polymorphisms with the susceptibility and clinical parameters of MS, in 455 consecutive patients and 366 controls.

METHODS

A multiplex polymerase chain reaction (PCR) was used to detect the deletions in GSTM1 and GSTT1 genes.

RESULTS

Patients with MS had significantly higher frequency of GSTT1 null genotype compared to controls (37.36% vs. 21.86%, respectively, p<0.0001, adjusted OR 2.13 (1.56-2.90)), as well as double deletions (15.38% vs. 10.38%, respectively, p<0.05). The carriers of GSTM1 deletion had significantly earlier onset of MS compared to the wild-type carriers (28.31 ± 8.45 vs. 30.64 ± 9.30 years, respectively, p = 0.03).

CONCLUSION

This study suggests the potential pathogenic role of GSTT1 deletion on MS susceptibility. There are no similar data published so far, yet this study should be replicated in other populations.

Influence of genetic polymorphisms on biomarkers of exposure and effects in children living in Upper Silesia

This article is a follow-up to our previous molecular epidemiology studies on the DNA damage in children from the Upper Silesia region of Poland. It is expected that metabolic and DNA repair gene polymorphisms may modulate individual susceptibility to environmental exposure. In this study, we investigate the association between polymorphisms of metabolising (CYP2D, EPHX1, GSTM1, GSTP1, GSTT1, NAT2) and DNA repair (XPD, XRCC1, XRCC3) genes and selected biomarkers of exposure and effect such as levels of 1-hydroxypyrene (1-OHP) and urinary mutagenicity, aromatic DNA adducts, sister chromatid exchange (SCE) and micronuclei (MN) in 74 children. Both 1-OHP concentration and urinary mutagenicity tested by TA98+S9 were significantly higher in individuals with EPHX1 (exon 4) Arg/Arg genotype than in individuals with other genotype. The EPHX1 (exon 3) significantly affected urinary mutagenicity tested with strain YG1024+S9. The urinary mutagenicity in individuals with Tyr/Tyr homozygotes was lower than in individuals with Tyr/His and His/His (1057±685 vs. 1432±1003 revertants/mol creatinine). XRCC3 Met/Met genotype was associated with significantly higher levels of 1-OHP in urine compared with only The/Met genotype. The PAH-DNA adduct levels in the subgroup with GSTM1 null genotype was 2-fold higher than in individuals with GSTM1 active (7.06±5.12 vs. 13.14±9.81 adduct/10(8) nucleotides). The mean level of aromatic DNA adducts in children with deletion of the GSTT1 gene was significantly higher compared with individuals with that gene present (8.03±6.23 vs. 14.66±10.70 adduct/10(8) nucleotides). Also the carriers of the XPD Lys/Lys genotype showed higher levels of DNA adducts than heterozygotes (13.16±9.70 vs. 6.81±5.86 adducts/10(8) nucleotides). Children carrying the XRCC3-241 Met/Met genotype exhibited a higher number of SCE in peripheral blood lymphocytes than carriers of Thr/Met allele (8.15±0.86 vs. 7.62±0.79 SCE/cell). It was also observed that children with the GSTP1 slow conjugator had significantly elevated MN in peripheral blood lymphocytes compared with fast conjugator (4.23±3.49 vs. 6.56±5.00 MN/1000 cells).

Dysregulation of glutathione homeostasis in neurodegenerative diseases

Dysregulation of glutathione homeostasis and alterations in glutathione-dependent enzyme activities are increasingly implicated in the induction and progression of neurodegenerative diseases, including Alzheimer’s, Parkinson’s and Huntington’s diseases, amyotrophic lateral sclerosis, and Friedreich’s ataxia. In this review background is provided on the steady-state synthesis, regulation, and transport of glutathione, with primary focus on the brain. A brief overview is presented on the distinct but vital roles of glutathione in cellular maintenance and survival, and on the functions of key glutathione-dependent enzymes. Major contributors to initiation and progression of neurodegenerative diseases are considered, including oxidative stress, protein misfolding, and protein aggregation. In each case examples of key regulatory mechanisms are identified that are sensitive to changes in glutathione redox status and/or in the activities of glutathione-dependent enzymes. Mechanisms of dysregulation of glutathione and/or glutathione-dependent enzymes are discussed that are implicated in pathogenesis of each neurodegenerative disease. Limitations in information or interpretation are identified, and possible avenues for further research are described with an aim to elucidating novel targets for therapeutic interventions. The pros and cons of administration of N-acetylcysteine or glutathione as therapeutic agents for neurodegenerative diseases, as well as the potential utility of serum glutathione as a biomarker, are critically evaluated.