Glutathione S-transferase T1, O1 and O2 polymorphisms are associated with survival in muscle invasive bladder cancer patients

GSTO2 ameliorates human neuroblastoma cell apoptosis, inflammation, ferroptosis, and oxidative stress by upregulating GPX4 expression in intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a severe hemorrhagic stroke and induces severe secondary neurological injury. However, its pathogenesis remains to be explored. The present work investigates the role of glutathione S-transferase omega 2 (GSTO2) in ICH and the underlying mechanism. Human neuroblastoma cells (SK-N-SH) were stimulated using hemin to mimic ICH-like injury. Protein expression levels of GSTO2 and glutathione peroxidase 4 (GPX4) were detected by western blot analysis assay. Cell viability was assessed by cell counting kit-8 assay. Cell proliferation was investigated by 5-ethynyl-2'-deoxyuridine assay. Cell apoptosis was analyzed by flow cytometry. Interleukin-6 and tumor necrosis factor-α levels were quantified by enzyme-linked immunosorbent assays. Fe2+ colorimetric assay kit was used to detect Fe2+ level. A cellular reactive oxygen species (ROS) assay kit was used to detect ROS levels. Malondialdehyde (MDA) level was assessed using the MDA content assay kit. GSH level was quantified using the GSH assay kit. Co-immunoprecipitation assay was performed to identify the association between GSTO2 and GPX4. Hemin stimulation suppressed SK-N-SH cell proliferation and promoted cell apoptosis, cell inflammation, ferroptosis, and oxidative stress. GSTO2 expression was downregulated in hemin-treated SK-N-SH cells in comparison with the control group. In addition, ectopic GSTO2 expression counteracted hemin-induced inhibitory effect on cell proliferation and promoting effects on cell apoptosis, inflammation, ferroptosis, and oxidative stress. Moreover, GSTO2 was associated with GPX4 in SK-N-SH cells. GPX4 silencing attenuated GSTO2 overexpression-induced effects on hemin-stimulated SK-N-SH cell injury. GSTO2 ameliorated SK-N-SH cell apoptosis, inflammation, ferroptosis, and oxidative stress by upregulating GPX4 expression in ICH, providing a therapeutic strategy for ICH.

Glutathione S-transferase omega class 1 (GSTO1)-associated large extracellular vesicles are involved in tumor-associated macrophage-mediated cisplatin resistance in bladder cancer

Bladder cancer poses a significant challenge to chemotherapy due to its resistance to cisplatin, especially at advanced stages. Understanding the mechanisms behind cisplatin resistance is crucial for improving cancer therapy. The enzyme glutathione S-transferase omega class 1 (GSTO1) is known to be involved in cisplatin resistance in colon cancer. This study focused on its role in cisplatin resistance in bladder cancer. Our analysis of protein expression in bladder cancer cells stimulated by secretions from tumor-associated macrophages (TAMs) showed a significant increase in GSTO1. This prompted further investigation into the role of GSTO1 in bladder cancer. We found a strong correlation between GSTO1 expression and cisplatin resistance. Mechanistically, GSTO1 triggered the release of large extracellular vesicles (EVs) that promoted cisplatin efflux, thereby reducing cisplatin-DNA adduct formation and enhancing cisplatin resistance. Inhibition of EV release effectively counteracted the cisplatin resistance associated with GSTO1. In conclusion, GSTO1-mediated EV release may contribute to cisplatin resistance caused by TAMs in bladder cancer. Strategies to target GSTO1 could potentially improve the efficacy of cisplatin in treating bladder cancer.

Polymorphisms in drug-metabolizing genes and urinary bladder cancer susceptibility and prognosis: Possible impacts and future management

Epidemiological studies have shown the association of genetic variants with risks of occupational and environmentally induced cancers, including bladder (BC). The current review summarizes the effects of variants in genes encoding phase I and II enzymes in well-designed studies to highlight their contribution to BC susceptibility and prognosis. Polymorphisms in genes codifying drug-metabolizing proteins are of particular interest because of their involvement in the metabolism of exogenous genotoxic compounds, such as tobacco and agrochemicals. The prognosis between muscle-invasive and non-muscle-invasive diseases is very different, and it is difficult to predict which will progress worse. Web of Science, PubMed, and Medline were searched to identify studies published between January 1, 2010, and February 2023. We included 73 eligible studies, more than 300 polymorphisms, and 46 genes/loci. The most studied candidate genes/loci of phase I metabolism were CYP1B1, CYP1A1, CYP1A2, CYP3A4, CYP2D6, CYP2A6, CYP3E1, and ALDH2, and those in phase II were GSTM1, GSTT1, NAT2, GSTP1, GSTA1, GSTO1, and UGT1A1. We used the 46 genes to construct a network of proteins and to evaluate their biological functions based on the Reactome and KEGG databases. Lastly, we assessed their expression in different tissues, including normal bladder and BC samples. The drug-metabolizing pathway plays a relevant role in BC, and our review discusses a list of genes that could provide clues for further exploration of susceptibility and prognostic biomarkers.

The Polymorphisms in GSTO Genes (GSTO1 rs4925, GSTO2 rs156697, and GSTO2 rs2297235) Affect the Risk for Testicular Germ Cell Tumor Development: A Pilot Study

Members of the omega class of glutathione transferases (GSTs), GSTO1, and GSTO2, catalyze a range of reduction reactions as a part of the antioxidant defense system. Polymorphisms of genes encoding antioxidant proteins and the resultant altered redox profile have already been associated with the increased risk for testicular germ cell cancer (GCT) development. The aim of this pilot study was to assess the individual, combined, haplotype, and cumulative effect of GSTO1rs4925, GSTO2rs156697, and GSTO2rs2297235 polymorphisms with the risk for testicular GCT development, in 88 patients and 96 matched controls, through logistic regression models. We found that carriers of the GSTO1*C/A*C/C genotype exhibited an increased risk for testicular GCT development. Significant association with increased risk of testicular GCT was observed in carriers of GSTO2rs2297235*A/G*G/G genotype, and in carriers of combined GSTO2rs156697*A/G*G/G and GSTO2rs2297235*A/G*G/G genotypes. Haplotype H7 (GSTO1rs4925*C/GSTO2rs2297235*G/GSTO2rs156697*G) exhibited higher risk of testicular GCT, however, without significant association (p > 0.05). Finally, 51% of testicular GCT patients were the carriers of all three risk-associated genotypes, with 2.5-fold increased cumulative risk. In conclusion, the results of this pilot study suggest that GSTO polymorphisms might affect the protective antioxidant activity of GSTO isoenzymes, therefore predisposing susceptible individuals toward higher risk for testicular GCT development.

The Upregulation of GSTO2 is Associated with Colon Cancer Progression and a Poor Prognosis

Colorectal cancer is the second-leading cause of cancer-related mortality in the United States. Glutathione S-transferase can affect the development of cancer. Glutathione S-transferase omega 2, a member of the GST family, plays an important role in many tumors. However, the role of Glutathione S-transferase omega 2 in the development of colon cancer remains unclear. Herein, our study aimed to investigate the exact role of Glutathione S-transferase omega 2 in colon cancer. We used RNA sequencing data from The Cancer Genome Atlas and the Genotype-Tissue Expression database to analyze Glutathione S-transferase omega 2 expressions. Then, we explore the protein information of Glutathione S-transferase omega 2 in the Human Protein Atlas, GeneCards, and String database. In addition, western blot and immunohistochemistry were performed to evaluate the protein levels of Glutathione S-transferase omega 2 in colon cancer tissues. We acquire data from the Gene Expression Omnibus and The Cancer Genome Atlas databases. Also, we performed relevant prognostic analyses of these data. In addition, we performed a statistical analysis of the clinical data from The Cancer Genome Atlas database and the expression level of Glutathione S-transferase omega 2. Then, we performed Cox regression analysis and found independent risk factors for prognosis in patients with colon cancer. The Kyoto Encyclopedia of Genes and Genomes and Gene Ontology enrichment analyses were used to explore the potential biological functions of Glutathione S-transferase omega 2. The infiltration of colon cancer-immune cells was evaluated by the CIBERSORT method. RNA silencing was performed using siRNA constructs in HCT-116 and HT-29 cell lines. Cell Counting Kit-8 and EdU assays were performed to determine cell proliferation. Transwell experiments and scratch tests were used to determine cell migration. As for the mRNA and protein expression levels of cells, we used quantitative real-time PCR and western blot to detect them. Our research shows that Glutathione S-transferase omega 2 is overexpressed in colon cancer patients, and this overexpression is associated with a poor prognosis. The high expression of Glutathione S-transferase omega 2 is significantly correlated stage with stage, M, and N classification progression in colon cancer by statistical analysis. Univariate and multivariate Cox regression analyses showed that Glutathione S-transferase omega 2 was an independent risk factor for poor prognosis in colon cancer. In addition, we also found that Glutathione S-transferase omega 2 expression levels can affect the immune microenvironment of colon cancer cells. Gene silencing of Glutathione S-transferase omega 2 in HT-29 and HCT-116 cells significantly inhibited tumor growth and migration. In summary, we found that Glutathione S-transferase omega 2 can be used as a molecular indicator of colon cancer prognosis. In vitro, gene silencing of Glutathione S-transferase omega 2 inhibited colon cancer cells' growth and migration.

Genetic Variants Associated with Chronic Kidney Disease in a Spanish Population

Chronic kidney disease (CKD) patients have many affected physiological pathways. Variations in the genes regulating these pathways might affect the incidence and predisposition to this disease. A total of 722 Spanish adults, including 548 patients and 174 controls, were genotyped to better understand the effects of genetic risk loci on the susceptibility to CKD. We analyzed 38 single nucleotide polymorphisms (SNPs) in candidate genes associated with the inflammatory response (interleukins IL-1A, IL-4, IL-6, IL-10, TNF-α, ICAM-1), fibrogenesis (TGFB1), homocysteine synthesis (MTHFR), DNA repair (OGG1, MUTYH, XRCC1, ERCC2, ERCC4), renin-angiotensin-aldosterone system (CYP11B2, AGT), phase-II metabolism (GSTP1, GSTO1, GSTO2), antioxidant capacity (SOD1, SOD2, CAT, GPX1, GPX3, GPX4), and some other genes previously reported to be associated with CKD (GLO1, SLC7A9, SHROOM3, UMOD, VEGFA, MGP, KL). The results showed associations of GPX1, GSTO1, GSTO2, UMOD, and MGP with CKD. Additionally, associations with CKD related pathologies, such as hypertension (GPX4, CYP11B2, ERCC4), cardiovascular disease, diabetes and cancer predisposition (ERCC2) were also observed. Different genes showed association with biochemical parameters characteristic for CKD, such as creatinine (GPX1, GSTO1, GSTO2, KL, MGP), glomerular filtration rate (GPX1, GSTO1, KL, ICAM-1, MGP), hemoglobin (ERCC2, SHROOM3), resistance index erythropoietin (SOD2, VEGFA, MTHFR, KL), albumin (SOD1, GSTO2, ERCC2, SOD2), phosphorus (IL-4, ERCC4 SOD1, GPX4, GPX1), parathyroid hormone (IL-1A, IL-6, SHROOM3, UMOD, ICAM-1), C-reactive protein (SOD2, TGFB1,GSTP1, XRCC1), and ferritin (SOD2, GSTP1, SLC7A9, GPX4). To our knowledge, this is the second comprehensive study carried out in Spanish patients linking genetic polymorphisms and CKD.

Systematic Review: Genetic Associations for Prognostic Factors of Urinary Bladder Cancer

INTRODUCTION

Many germline associations have been reported for urinary bladder cancer (UBC) outcomes and prognostic characteristics. It is unclear whether there are overlapping genetic patterns for various prognostic endpoints. We aimed to review contemporary literature on genetic associations with UBC prognostic outcomes and to identify potential overlap in reported genes.

METHODS

EMBASE, MEDLINE, and PubMed databases were queried for relevant articles in English language without date restrictions. The initial search identified 1346 articles. After exclusions, 112 studies have been summarized. Cumulatively, 316 single-nucleotide polymorphisms (SNPs) were reported across prognostic outcomes (recurrence, progression, death) and characteristics (tumor stage, grade, size, age, risk group). There were considerable differences between studied outcomes in the context of genetic associations. The most commonly reported SNPs were located in OGG1, TP53, and MDM2. For outcomes with the highest number of reported associations (ie, recurrence and death), functional enrichment annotation yields different terms, potentially indicating separate biological mechanisms.

CONCLUSIONS

Our study suggests that all UBC prognostic outcomes may have different biological origins with limited overlap. Further validation of these observations is essential to target a phenotype that could best predict patient outcome and advance current management practices.

GSTO1*CC Genotype (rs4925) Predicts Shorter Survival in Clear Cell Renal Cell Carcinoma Male Patients

Omega class glutathione transferases, GSTO1-1 and GSTO2-2, exhibit different activities involved in regulation of inflammation, apoptosis and redox homeostasis. We investigated the the prognostic significance of GSTO1 (rs4925) and GSTO2 (rs156697 and rs2297235) polymorphisms in clear cell renal cell carcinoma (ccRCC) patients. GSTO1-1 and GSTO2-2 expression and phosphorylation status of phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt)/ /mammalian target of rapamycin (mTOR) and Raf/MEK/extracellular signal-regulated kinase (ERK) signaling pathways in non-tumor and tumor ccRCC tissue, as well as possible association of GSTO1-1 with signaling molecules were also assessed. GSTO genotyping was performed by quantitative PCR in 228 ccRCC patients, while expression and immunoprecipitation were analyzed by Western blot in 30 tissue specimens. Shorter survival in male carriers of GSTO1*C/C wild-type genotype compared to the carriers of at least one variant allele was demonstrated (p = 0.049). GSTO1*C/C genotype independently predicted higher risk of overall mortality among male ccRCC patients (p = 0.037). Increased expression of GSTO1-1 and GSTO2-2 was demonstrated in tumor compared to corresponding non-tumor tissue (p = 0.002, p = 0.007, respectively), while GSTO1 expression was correlated with interleukin-1β (IL-1β)/pro-interleukin-1β (pro-IL-1β) ratio (r = 0.260, p = 0.350). Interaction of GSTO1 with downstream effectors of investigated pathways was shown in ccRCC tumor tissue. This study demonstrated significant prognostic role of GSTO1 polymorphism in ccRCC. Up-regulated GSTO1-1 and GSTO2-2 in tumor tissue might contribute to aberrant ccRCC redox homeostasis.

Glutathione S-Transferase Gene Polymorphisms are Associated with an Improved Treatment Response to Cisplatin-Based Chemotherapy in Patients with Non-Small Cell Lung Cancer (NSCLC): A Meta-Analysis

BACKGROUND Previous studies have shown an association with glutathione S-transferase (GST) gene polymorphisms in patients with non-small cell lung cancer (NSCLC) and treatment response. This study aimed to undertake a literature review and meta-analysis of GST gene polymorphisms, including GSTT1, GSTM1, and GSTP1 IIe105Val, and the treatment response to cisplatin-based chemotherapy in patients with NSCLC. MATERIAL AND METHODS A literature search was undertaken of the main medical publication databases for publications, up to March 2017, on the association between GSTT1, GSTM1, and GSTP1 IIe105Val polymorphisms and the clinical outcome in patients with NSCLC treated with cisplatin-based chemotherapy. A random fixed-effects model was used to calculate the pooled odds ratio (OR) and 95% confidence interval (CI) to evaluate the associations, considering multiple genetic models. A subgroup analysis according to ethnicity was performed. RESULTS Twenty-three published studies were identified that showed that both the null GSTM1 and the GG genotype of GSTP1 IIe105Val were associated with improved treatment response to cisplatin-based chemotherapy (GSTT1 present/null: OR=1.328; 95% CI, 1.074-1.643) (GSTP1 GG + AG vs. AA: OR=0.596; 95% CI, 0.468-0.759). In subgroup analysis, the GSTP1 polymorphism was significantly associated with treatment response in East-Asian patients, but not in Caucasian patients. CONCLUSIONS Meta-analysis showed that the GG genotype of GSTP1 IIe105Val and the null GSTM1 genotype were associated with an improved treatment response to cisplatin-based chemotherapy in patients with NSCLC, especially in East-Asian patients.

GSTM1 and GSTT1 polymorphisms are associated with increased bladder cancer risk: Evidence from updated meta-analysis

BACKGROUND

Previous studies have indicated association between GSTM1 and GSTT1 gene polymorphisms and bladder cancer susceptibility, but the results have been inconclusive. Here, we performed a meta-analysis to investigate the association between GSTM1/GSTT1 deletion polymorphisms and bladder cancer susceptibility.

METHODS

We searched for all studies investigating the association between GSTM1 or GSTT1 polymorphism and bladder cancer susceptibility in Pubmed, Web of Knowledge, and the Cochrane Central Search Library. A systematic review and meta-analysis were performed. Subgroup analyses were performed on different ethnicity, population-based and smoking status.

RESULTS

Our search identified 63 studies. GSTM1 null, GSTT1 null and GSTM1/GSTT1 double-null genotypes were associated with increased risk of bladder cancer (OR: 1.36 95% CI: 1.25-1.47, P<0.01; OR: 1.13 95% CI: 1.02-1.25, P<0.01; OR: 1.84 95% CI: 1.50-2.26, P<0.01). Subgroup analyses indicated that the GSTM1-null genotype was associated with increased risk of bladder cancer in Caucasians and Asians, while the GSTT1-null genotype was associated with increased risk of bladder cancer in Caucasians. The GSTM1/GSTT1 double-null genotype was associated with increased risk of bladder cancer in Caucasians, Asians, and Africans. Stratified analyses of population-based associations indicated increased bladder cancer risk associated with GSTM1-null and GSTM1/GSTT1 double-null genotypes in hospital-based and population-based studies. GSTM1 deletion was associated with increased bladder cancer risk in both smokers and nonsmokers. Non-smokers with the GSTM1/GSTT1 double-null genotype had an increased bladder cancer risk.

CONCLUSION

This meta-analysis demonstrates that the GSTM1-null, GSTT1-null, and GSTM1/GSTT1 double-null genotypes are associated with increased bladder cancer risk.

GSTT1, GSTP1, and GSTM1 genetic variants are associated with survival in previously untreated metastatic breast cancer

Purpose

The polymorphisms in genes including GSTM1, GSTP1 and GSTT1 have been found to predict development and therapeutic efficacy in various malignancies. Breast cancer is one of most common cancers among women. In this study, we evaluated the prognostic value of three functional polymorphisms of GSTs in patients with previously untreated metastatic breast cancer (MBC).

Patients and Methods

The genotype of GSTT1, GSTP1, and GSTM1 in 170 patients with previously untreated MBC from one single center were assessed via PCR-based RFLP methods. The prognostic of polymorphisms on overall survival (OS) was examined using the Kaplan-Meier estimates and Cox proportional hazard ratio (HR) regression analyses.

Results

The null genotypes of GSTT1 and GSTM1 were significantly correlated to poor OS compared with the present genotypes, respectively. After adjusting for clinic-pathologic factors, GSTT1 and GSTM1 genetic variants were still significantly associated with OS (HR, 1.92; 95% CI, 1.26-2.91 and HR, 1.53; 95% CI, 1.05-2.23). GSTT1 and GSTM1 were independent survival predictors and GSTP1 was not associated with overall survival of previous untreated MBC.

Conclusion

This exploratory analysis suggests that in addition to clinic-pathologic factors, the genetic variants in GSTT1 and GSTM1 might be predictive of survival outcome in patients with previously untreated MBC.

Identification and Comparison of Differentiation-Related Proteins in Hepatocellular Carcinoma Tissues by Proteomics

Histological differentiation is a major pathological criterion indicating the risk of tumor invasion and metastasis in patients with hepatocellular carcinoma. The degree of tumor differentiation is controlled by a complex interacting network of associated proteins. The principal aim of the present study is to identify the possible differentiation-related proteins which may be used for early diagnosis and more effective therapies. We compared poorly differentiated and well-differentiated hepatocellular carcinoma tissues by using 2-dimensional gel electrophoresis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Among the 11 identified protein spots, 6 were found to be upregulated in poorly differentiated hepatocellular carcinoma tissues and 5 were correspondingly downregulated. Immunohistochemistry was performed on 106 hepatocellular carcinoma tissues to confirm the results of the proteomic analysis. By using bioinformatic tools GO and STRING, these proteins were found to be related to catalytic activity, binding, and antioxidant activity. In particular, our data suggest that overexpression of peroxiredoxin-2, annexin A2, and heat shock protein β-1 was correlated with tumor invasion, metastasis, and poor prognosis, and therefore, these proteins may serve as potential diagnostic and therapeutic biomarkers.

Occupational bladder cancer: Polymorphisms of xenobiotic metabolizing enzymes, exposures, and prognosis

Approximately 7% of all bladder cancer cases in males are associated with occupation. The question arises whether the use of genome-wide association studies was able to identify bladder cancer risk factors that may modulate occupational bladder cancer risk and prognosis. One hundred and forty-three bladder cancer cases with suspected occupational bladder cancer and 337 controls were genotyped for the following polymorphisms: N-acetyltransferase 2 (NAT2), glutathione S-transferase M1 (GSTM1), glutathione S-transferase T1 (GSTT1), UDP-glucuronyltransferase 1A rs11892031 (UGT1A), rs9642880 (close to c-MYC), and rs710521 (close to TP63). The most relevant polymorphisms for occupational bladder cancer risk were GSTM1 and UGT1A, especially when co-occurring (GSTM1 negative and rs11892031[A/A]: 48% cases vs. 38% controls, OR 1.47, 95% CI 0.99-2.20). The effect was more pronounced in smokers. GSTM1 negative genotype occurred more frequently in cancer cases exposed to aromatic amines, carbolineum, and in painters and varnishers. UGT1A (rs11892031[A/A]) was found frequently in cases exposed to carbolineum, crack test spray, PAH, and in painters and varnishers. All investigated polymorphisms except rs710521 (TP63) seemed to exert an impact on recurrence risk. Relapse-free times were shorter for NAT2 slow and ultra-slow, GSTT1 positive and GSTM1 negative cases. Occupational bladder cancer cases with a number of risk variants displayed significantly shorter relapse-free times compared to cases with few, less relevant risk alleles as evidenced by median difference 8 months. In conclusion, in the present, suspected occupational bladder cancer cases phase II polymorphisms involved in bladder carcinogen metabolism modulate bladder cancer recurrence. Most relevant for bladder cancer risk were GSTM1 and UGT1A but not NAT2.

Skin score correlates with global DNA methylation and GSTO1 A140D polymorphism in arsenic-affected population of Eastern India

Arsenic is a potent environmental toxicant causing serious public health concerns in India, Bangladesh and other parts of the world. Gene- and promoter-specific hypermethylation has been reported in different arsenic-exposed cell lines, whereas whole genome DNA methylation study suggested genomic hypo- and hypermethylation after arsenic exposure in in vitro and in vivo studies. Along with other characteristic biomarkers, arsenic toxicity leads to typical skin lesions. The present study demonstrates significant correlation between severities of skin manifestations with their whole genome DNA methylation status as well as with a particular polymorphism (Ala 140 Asp) status in arsenic metabolizing enzyme Glutathione S-transferase Omega-1 (GSTO1) in arsenic-exposed population of the district of Nadia, West Bengal, India.

Upregulated glutathione transferase omega-1 correlates with progression of urinary bladder carcinoma

OBJECTIVES

Newly discovered glutathione transferase omega 1 (GSTO1-1) plays an important role in the glutathionylation cycle, a significant mechanism of protein function regulation. GSTO1-1 expression pattern has not been studied in transitional cell carcinoma (TCC), as yet.

METHODS

A total of 56 TCC tumor and corresponding non-tumor specimens were investigated. Glutathione content and thioltransferase activity were measured spectrophotometrically. Protein-glutathione mixed disulfides were measured fluorimetrically. GSTO1-1 expression was determined by immunoblot and qPCR. Immunoprecipitation with GSTO1-1 antibody was followed by immunoblot using anti-GSTO1, GSTP1, c-Jun, JNK, Akt, phospho-Akt, and ASK1 antibody, while for the total S-glutathionylation levels non-reducing electrophoresis was performed.

RESULTS

The contents of reduced glutathione and thioltransferase activity were significantly increased in tumor compared to non-tumor tissue. The increased GSTO1 expression in tumor tissue showed clear correlation with grade and stage. However, decreased total protein glutathionylation level in tumor compared to non-tumor samples was found. Immunoprecipitation has shown an association of GSTO1-1 with GSTP1, Akt, phospho-Akt, and ASK1 proteins.

CONCLUSIONS

GSTO1 deglutathionylase activity suggests its potential important role in redox perturbations present in TCC. Increased GSTO1-1 expression might contribute to TCC development and/or progression supporting the notion that GSTO1-1 may be a promising novel cancer target.

Role of GSTP1 Ile105Val and XRCC1 Arg194Trp, Arg280His and Arg399Gln gene polymorphisms in the clinical outcome of advanced non-small cell lung cancer

We conducted a study to investigate the association between the clinical outcome and GSTP1 Ile105Val and XRCC1 Arg194Trp, Arg280His and Arg399Gln gene polymorphisms in advanced NSCLC patients with cisplatin-based chemotherapy. Between January 2010 and December 2012, a total of 206 patients with advanced NSCLC were histopathologically confirmed were included into analysis. By logistic regression analysis, individuals carrying the AG and GG genotypes of GSTP1 Ile105Val were associated with better response to chemotherapy when compared with the AA genotype, and the adjusted Ors (95% CI) were 2.06 (1.10-3.86) and 4.89 (1.52-18.33), respectively. The TT genotype of XRCC1 Arg194Trp was correlated with better response to chemotherapy compared to the CC genotype, and the adjusted OR (95% CI) was 3.23 (1.20-9.30). By Cox Hazard Proportional Model, the GG genotype of GSTP1 Ile105Val and the TT genotype of XRCC1 Arg194Trp were found to be associated with lower risk of death from all causes when compared with the wide-type genotype, and the adjusted HRs (95% CI) were 0.05 (0.01-0.18) and 0.20 (0.07-0.62), respectively. Moreover, individuals carrying both the G/A+G/G genotype of GSTP1 Ile105Val and the G/A+A/A of XRCC1 Arg194Trp were associated with heavy greater CR+PR response to chemotherapy (OR=2.98, 95% CI=1.39-6.42), and also correlated with longer overall survival of advanced NSCLC (HR=0.19, 95% CI=0.05-0.61). In conclusion, we found that the GSTP1 Ile105Val and XRCC1 Arg194Trp were associated with better response to chemotherapy and longer survival of advanced NSCLC, compared to the wide-type genotype.

GSTP1 and GSTO1 single nucleotide polymorphisms and the response of bladder cancer patients to intravesical chemotherapy

SNPs may restrict cell detoxification activity and be a potential risk factor for cancer chemosensitivity. We evaluated the predictive value of these polymorphisms on the sensitivity of bladder cancer patients to epirubicin and mitomycin chemotherapy instillation as well as their toxicities. SNPs were analyzed by TaqMan genotyping assays in 130 patients treated with epirubicin and 114 patients treated with mitomycin. Recurrence-free survival (RFS) was estimated by the Kaplan-Meier method, and hazard ratios (HRs) and 95% confidence intervals (CIs) of the HRs were derived from multivariate Cox proportional hazard models. GSTP1 rs1695 and GSTO1 rs4925 were also associated with RFS in the epirubicin group. Patients carrying the GSTP1 AG+GG and GSTO1 AC+AA genotypes had an unfavorable RFS. Patients with the GSTP1 AA and GSTO1 CC genotypes had a reduced risk of recurrence after the instillation of epirubicin. In addition, patients with the GSTP1 rs1695 AA genotype had an increased risk of irritative voiding symptoms; while patients with the GSTO1 rs4925 CC genotype had a decreased risk of hematuria. Our results suggest that GSTP1 and GSTO1 polymorphisms are associated with epirubicin treatment outcomes as well as with epirubicin-related toxicity.

GSTO1*C/GSTO2*G haplotype is associated with risk of transitional cell carcinoma of urinary bladder

PURPOSE

To clarify the role of genetic polymorphisms of GSTO1 (rs4925) and GSTO2 (rs156697) in individual susceptibility to urinary bladder cancer.

METHODS

Case-control study consisting of 187 patients with histologically confirmed transitional cell carcinoma (TCC) of urinary bladder and 140 age- and gender-matched cancer-free controls was carried out. Genotyping of GSTO1 and GSTO2 was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

We found that carriers of mutant GSTO2*G/G genotype were at increased risk of the development of TCC (OR 2.6, 95% CI 1.2-5.8, p = 0.041), while GSTO1 rs4925 polymorphism was not significantly associated with TCC risk (p = 0.450). According to smoking status, smokers with GSTO2*G/G genotype had significantly higher risk of TCC of urinary bladder (OR 4.3, 95% CI 1.6-11.2, p = 0.003) compared to wild-type carriers with no smoking history. We further analyzed the effects of GSTO1/GSTO2 haplotypes on TCC risk, based on the linkage disequilibrium found for GSTO1 (rs4925) and GSTO2 (rs156697) (D' = 0.309, p = 0.001). The study subjects with GSTO1*C/GSTO2*G (GSTO1 wild-type/GSTO2 mutant) haplotype were at the highest risk of the development of transitional cell carcinoma of urinary bladder (OR 2.8, 95% CI 1.5-5.2, p = 0.002).

CONCLUSIONS

Our results indicate that GSTO1*C/GSTO2*G haplotype is associated with increased risk of TCC. The modifying effect of GSTO2*G/G genotype on individual susceptibility to TCC is more pronounced, when associated with smoking.