Enhanced GSTP1 expression in transitional cell carcinoma of urinary bladder is associated with altered apoptotic pathways

Involvement of GSTP1 in low dose radiation-induced apoptosis in GM12878 cells

BACKGROUND

Low-dose ionizing radiation-induced protection and damage are of great significance among radiation workers. We aimed to study the role of glutathione S-transferase Pi (GSTP1) in low-dose ionizing radiation damage and clarify the impact of ionizing radiation on the biological activities of cells.

RESULTS

In this study, we collected peripheral blood samples from healthy adults and workers engaged in radiation and radiotherapy and detected the expression of GSTP1 by qPCR. We utilized γ-rays emitted from uranium tailings as a radiation source, with a dose rate of 14 μGy/h. GM12878 cells subjected to this radiation for 7, 14, 21, and 28 days received total doses of 2.4, 4.7, 7.1, and 9.4 mGy, respectively. Subsequent analyses, including flow cytometry, MTS, and other assays, were performed to assess the ionizing radiation's effects on cellular biological functions. In peripheral blood samples collected from healthy adults and radiologic technologist working in a hospital, we observed a decreased expression of GSTP1 mRNA in radiation personnel compared to the healthy controls. In cultured GM12878 cells exposed to low-dose ionizing radiation from uranium tailings, we noted significant changes in cell morphology, suppression of proliferation, delay in cell cycle progression, and increased apoptosis. These effects were partially reversed by overexpression of GSTP1. Moreover, low-dose ionizing radiation increased GSTP1 gene methylation and downregulated GSTP1 expression. Furthermore, low-dose ionizing radiation affected the expression of GSTP1-related signaling molecules.

CONCLUSIONS

This study shows that low-dose ionizing radiation damages GM12878 cells and affects their proliferation, cell cycle progression, and apoptosis. In addition, GSTP1 plays a modulating role under low-dose ionizing radiation damage conditions. Low-dose ionizing radiation affects the expression of Nrf2, JNK, and other signaling molecules through GSTP1.

Comparative proteomics analysis in different stages of urothelial bladder cancer for identification of potential biomarkers: highlighted role for antioxidant activity

BACKGROUND

Non-muscle-invasive bladder cancer (NMIBC) has a high recurrence rate and muscle-invasive bladder cancer (MIBC) has unfavorable outcomes in urothelial bladder cancer (UBC) patients. Complex UBC-related protein biomarkers for outcome prediction may provide a more efficient management approach with an improved clinical outcome. The aim of this study is to recognize tumor-associated proteins, which are differentially expressed in different stages of UBC patients compared non-cancerous tissues.

METHODS

The proteome of tissue samples of 42 UBC patients (NMIBC n = 25 and MIBC n = 17) was subjected to two-dimensional electrophoresis (2-DE) combined with Liquid chromatography-mass spectrometry (LC-MS) system to identify differentially expressed proteins. The intensity of protein spots was quantified and compared with Prodigy SameSpots software. Functional, pathway, and interaction analyses of identified proteins were performed using geneontology (GO), PANTHER, Reactome, Gene MANIA, and STRING databases.

RESULTS

Twelve proteins identified by LC-MS showed differential expression (over 1.5-fold, p < 0.05) by LC-MS, including 9 up-regulated in NMIBC and 3 up-regulated in MIBC patients. Proteins involved in the detoxification of reactive oxygen species and cellular responses to oxidative stress showed the most significant changes in UBC patients. Additionally, the most potential functions related to these detected proteins were associated with peroxidase, oxidoreductase, and antioxidant activity.

CONCLUSION

We identified several alterations in protein expression involved in canonical pathways which were correlated with the clinical outcomes suggested might be useful as promising biomarkers for early detection, monitoring, and prognosis of UBC.

The GSTP1/MAPKs/BIM/SMAC modulatory actions of nitazoxanide: Bioinformatics and experimental evidence in subcutaneous solid Ehrlich carcinoma-inoculated mice

AIMS

Ehrlich ascites carcinoma and its subcutaneous inoculated solid tumour form (SEC) are reliable models for chemotherapeutic molecular targets exploration. Novel chemotherapeutic approaches are identified as molecular targets for intrinsic apoptosis, like the modulation of the second mitochondria-derived activator of caspases (SMAC). SMAC is a physiological substrate of mitogen-activated protein kinases (MAPKs). Glutathione-S-transferase P1 (GSTP1) and its close association with MAPKs play an important role in malignant cell proliferation, metastasis, and resistance to chemotherapeutics. Nitazoxanide (NTZ) is an emerging cancer therapy and its targeted GSTP1 evidence remains a knowledge need.

MAIN METHODS

In the present mice-established SEC, the chemotherapeutic roles of oral NTZ (200 mg/kg/day) and 5-fluorouracil (5-FU; 20 mg/kg/day, intraperitoneally) regimens were evaluated by measuring changes in tumour mass, the tumour MAPKs, cytochrome c, Bcl-2 interacting mediator of cell death (BIM), and SMAC signalling pathway in addition to its molecular downstream; caspases 3 and 9.

KEY FINDINGS

Computational analysis for these target protein interactions showed direct-ordered interactions. After individual therapy with NTZ and 5-FU regimens, the histological architecture of the extracted tumour discs revealed decreases in viable tumour regions with significant necrosis surrounds. These findings were consistent with gross tumour sizes. Each separate regimen lowered the remarkable GSTP1 and elevated the low MAPKs expressions, cytochrome c, BIM, SMAC, and caspases 3, and 9 in EST tissues.

SIGNIFICANCE

The chemotherapeutic activity of NTZ in SEC was proven. Additionally, NTZ possesses a SMAC modulatory activity that, following thorough research, should be taken into consideration as a chemotherapeutic approach in solid tumours.

Targeting GSTP1-dependent ferroptosis in lung cancer radiotherapy: Existing evidence and future directions

Radiotherapy is applied in about 70% patients with tumors, yet radioresistance of tumor cells remains a challenge that limits the efficacy of radiotherapy. Ferroptosis, an iron-dependent lipid peroxidation regulated cell death, is involved in the development of a variety of tumors. Interestingly, there is evidence that ferroptosis inducers in tumor treatment can significantly improve radiotherapy sensitivity. In addition, related studies show that Glutathione S-transferase P1 (GSTP1) is closely related to the development of ferroptosis. The potential mechanism of targeting GSTP1 to inhibit tumor cells from evading ferroptosis leading to radioresistance has been proposed in this review, which implies that GSTP1 may play a key role in radiosensitization of lung cancer via ferroptosis pathway.

Genetic polymorphism of glutathione S-transferases (GSTM1, GSTT1, and GSTP1) in patients with bullous pemphigoid in a Polish population

Introduction. Bullous pemphigoid (BP) is one of the most common bullous diseases with an autoimmune background. The etiology and pathogenesis of BP are believed to be influenced not only by environmental, genetic, and immunological factors as well as by oxidative stress. BP is observed more frequently in elderly patients. Additionally, more potent oxidative stress is observed just in old age. Glutathione S-transferases (GSTs) play key roles in the detoxification of xenobiotics, metabolism of endogenous substrates, and the defense against oxidative stress. The present study examines whether polymorphism of genes encoding three selected GSTs (GSTM1, GSTT1, and GSTP1) might be associated with a higher risk for BP.

Materials and methods. The study involved 71 patients with BP and 100 healthy volunteers from a Polish population. The presence of the deletion type polymorphism for GSTM1 and GSTT1 was confirmed by multiplex PCR. The Ile105Val GSTP1 polymorphism was analyzed by PCR-RFLP.

Results. It was observed that the combination of GSTM1 null/GSTT1 null/GSTP1 Ile/Val, Val/Val genotypes occurred more frequently in patients with BP (8.5%) than in controls (4.0%). The odds ratio for carriers of GSTM1 null/GSTT1 null/ GSTP1 Ile/Val, Val/Val genotypes was 2.22 (95% CI 0.60–8.16; p = 0.3727), but was not statistically significant.

Conclusions. The combination of GSTM1 null, GSTT1 null, GSTP1 Ile/Val, Val/Val genotypes might be related to a greater risk of BP in a Polish population. However, future studies including more individuals are required to confirm this.

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

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

GSTP1 and cancer: Expression, methylation, polymorphisms and signaling (Review)

Glutathione S‑transferase Pi (GSTP1) is an isozyme encoded by the GST pi gene that plays an important regulatory role in detoxification, anti‑oxidative damage, and the occurrence of various diseases. The aim of the present study was to review the association between the expression of GSTP1 and the development and treatment of various cancers, and discuss GSTP1 methylation in several malignant tumors, such as prostate, breast and lung cancer, as well as hepatocellular carcinoma; to review the association between polymorphism of the GSTP1 gene and various diseases; and to review the effects of GSTP1 on electrophilic oxidative stress, cell signal transduction, and the regulation of carcinogenic factors. Collectively, GSTP1 plays a major role in the development of various diseases.

Evaluation of glutathione S-transferase pi 1 expression and gene promoter methylation in Moroccan patients with urothelial bladder cancer

BACKGROUND

Glutathione S-transferase pi 1 (GSTP1) is a cytosolic detoxifying enzyme that protects cells against deleterious effects of oxidative stress. Deregulated expression of GSTP1 protein and aberrant promoter methylation of GSTP1 gene were reported in various human tumors and were shown to be involved in the molecular pathway for cancer development.

AIMS AND METHODS

In this study, we aimed to determine the expression status of GSTP1 in relation to its gene promoter methylation in Moroccan population of 30 bladder cancer (BC) patients and in two noncancerous bladder tissues used as controls. GSTP1 expression was assessed by immunohistochemistry and GSTP1 gene promoter methylation status was studied by methylation-specific PCR (MS-PCR).

RESULTS

Glutathione S-transferase pi 1 was expressed in the two normal tissues. In BC cases, GSTP1 expression was strong in 23.33% (7/30), moderate in 60% (18/30), and weak in 13.33% (4/30) of cases, while GSTP1 was not expressed in one cancer case (3.33%). Variability of GSTP1 expression does not correlate with high-grade cancer or invasive-stage (p > 0.05). No GSTP1 gene promoter methylation was detected in all control and cancer cases.

CONCLUSION

Our data suggest that GSTP1 expression is not associated with BC development, limiting its use as a biomarker for BC management in Morocco. Moreover, difference in GSTP1 expression among BC cases is not due to GSTP1 promoter methylation.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

The Diagnostic Value of Nuclear Matrix Proteins in Bladder Cancer in the Aspect of Environmental Risk from Carcinogens

BACKGROUND

The interaction of environmental factors with genetic susceptibility and detoxification level seems to be an important causative factor in bladder cancer (BC). The aim of this study was to look for a BC marker panel which reflects the environmental risk. The nuclear matrix protein 22 (NMP22), bladder cancer-4 (BLCA-4), and total level proteins NMP22 and BLCA-4 (NMBL) in BC patients with genetic predisposition NAT2 (classified as slow acetylators, SA), DNA damage (8-OHdG), and detoxification by isoenzyme GSTπ activity were measured.

MATERIALS AND METHODS

The urine and blood from 91 BC patients and controls were examined, also according to tumor stage (T) and grade (G). The participants completed a questionnaire in order to evaluate environmental risk.

RESULTS

Most patients (75.3%) were previous or actual smokers. The levels of 8-OHdG, NMP22, BLCA-4, NMBL, and GSTπ were significantly higher in BC (p ≤ 0.001). The majority of patients (59.3%) were slow acetylators (SA). The highest BLCA-4/8-OHdG correlation was observed in total BC and SA smokers.

CONCLUSIONS

The total pool of nuclear matrix proteins in the urine (NMBL) has a higher diagnostic value in bladder cancer than single proteins. The particular value of BLCA-4 and GSTπ in the aspect of environmental risk was noted.

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.

Glutathione S-transferase expression in upper urinary tract urothelial carcinomas: a Taiwan study

OBJECTIVES

Glutathione S-transferase (GST) isoenzymes play important roles in resistance to cell apoptosis and carcinogenesis. We aimed to establish the relationship between GST expression and the prognosis of upper urinary tract urothelial carcinoma (UTT-UC) in Taiwan.

METHODS

This study retrospectively reviewed 46 patients with pathologically confirmed UUT-UC at Kaohsiung Medical University Hospital. In each patient, expression of GSTT1 and GSTP1 was compared between urothelial carcinoma and normal urothelial cells by Western blotting.

RESULTS

GSTP1 expression in the UUT-UC cells was significantly higher than that in normal urothelial cells (1.6 fold, p<0.001). Expression of GSTT1 was significantly associated with the invasiveness of the carcinoma (p=0.006).

CONCLUSIONS

In UUT-UC, GSTP1 might be a potential tumor marker, whereas high GSTT1 expression could be used as an indicator of cancer progression. This study is the first to demonstrate potential applications of different GST isoenzymes for biomolecular analysis of UUT-UCs in Taiwan.

Polymorphisms of NRF2 and NRF2 target genes in urinary bladder cancer patients

PURPOSE

NRF2 transcription factor is involved in modulation of various antioxidant and metabolic genes and, therefore, may modulate anti-carcinogenic potential. Association between polymorphisms of NRF2 and five NRF2-regulated genes and urinary bladder cancer (BC) risk was analyzed.

METHODS

The study group included 244 BC patients, while the control group comprised 365 individuals with no evidence of malignancy. Genotyping of GSTM1 (deletion), GSTT1 (deletion), GSTA1 -69C/T (rs3957357), GSTP1 Ile105Val (rs1695), SOD2 Ala16Val (rs4880) and NRF2 -617C/A (rs6721961) in blood genomic DNA was performed by means of real-time PCR assays. The associations between gene polymorphism and BC risk were computed by logistic regression.

RESULTS

The frequency of GSTA1, GSTP1, SOD2 and NRF2 genotypes did not differ in both groups. A significantly higher BC risk was associated with GSTM1 null genotype after adjusting to age, sex and smoking habit (OR 1.85, 95 % CI 1.30-2.62; P = 0.001). GSTT1 null (OR 0.50, 95 % CI 0.31-0.81; P = 0.005) and GSTP1 Val105Val (OR 0.52, 95 % CI 0.27-0.98; P = 0.04) genotypes were associated with reduced BC risk separately or in combination (OR 0.24, 95 % CI 0.11-0.51; P < 0.0001) (P heterogeneity = 0.01). Combined GSTT1 null and SOD2 with at least one 16Val allele among never smokers encompass reduced BC risk (OR 0.14, 95 % CI 0.03-0.63; P = 0.01) (P heterogeneity = 0.04).

CONCLUSIONS

This study supports hypothesis that GSTM1 null genotype may be a moderate BC risk factor. The gene-gene and gene-environment interactions associated with combined GSTP1/GSTT1 and combined GSTT1/SOD2 genetic polymorphisms along with cigarette smoking habit may play a significant role in BC risk modulation.

DNA Methylation profiles as predictors of recurrence in non muscle invasive bladder cancer: an MS-MLPA approach

Background

Although non muscle invasive bladder cancer (NMIBC) generally has a good long-term prognosis, up to 80% of patients will nevertheless experience local recurrence after the primary tumor resection. The search for markers capable of accurately identifying patients at high risk of recurrence is ongoing. We retrospectively evaluated the methylation status of a panel of 24 tumor suppressor genes (TIMP3, APC, CDKN2A, MLH1, ATM, RARB, CDKN2B, HIC1, CHFR, BRCA1, CASP8, CDKN1B, PTEN, BRCA2, CD44, RASSF1, DAPK1, FHIT, VHL, ESR1, TP73, IGSF4, GSTP1 and CDH13) in primary lesions to obtain information about their role in predicting local recurrence in NMIBC.

Methods

Formaldehyde-fixed paraffin-embedded (FFPE) samples from 74 patients operated on for bladder cancer were analyzed by methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA): 36 patients had relapsed and 38 were disease-free at the 5-year follow up. Methylation status was considered as a dichotomous variable and genes showing methylation ≥20% were defined as “positive”.

Results

Methylation frequencies were higher in non recurring than recurring tumors. A statistically significant difference was observed for HIC1 (P = 0.03), GSTP1 (P = 0.02) and RASSF1 (P = 0.03). The combination of the three genes showed 78% sensitivity and 66% specificity in identifying recurrent patients, with an overall accuracy of 72%.

Conclusions

Our preliminary data suggest a potential role of HIC1, GSTP1 and RASSF1 in predicting local recurrence in NMIBC. Such information could help clinicians to identify patients at high risk of recurrence who require close monitoring during follow up.

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

Objective

To examine the association of six glutathione transferase (GST) gene polymorphisms (GSTT1, GSTP1/rs1695, GSTO1/rs4925, GSTO2/rs156697, GSTM1, GSTA1/rs3957357) with the survival of patients with muscle invasive bladder cancer and the genotype modifying effect on chemotherapy.

Patients and Methods

A total of 105 patients with muscle invasive bladder cancer were included in the study. The follow-up lasted 5 years. The effect of GSTs polymorphisms on predicting mortality was analyzed by the Cox proportional hazard models, while Kaplan-Meier analysis was performed to assess differences in survival.

Results

GSTT1 active, GSTO1 Asp140Asp or GSTO2 Asp142Asp genotypes were independent predictors of a higher risk of death among bladder cancer patients (HR = 2.5, P = 0.028; HR = 2.9, P = 0.022; HR = 3.9, P = 0.001; respectively) and significantly influenced the overall survival. There was no association between GSTP1, GSTM1 and GSTA1 gene variants with overall mortality. Only GSTO2 polymorphism showed a significant effect on the survival in the subgroup of patients who received chemotherapy (P = 0.006).

Conclusion

GSTT1 active genotype and GSTO1 Asp140Asp and GSTO2 Asp142Asp genotypes may have a prognostic/pharmacogenomic role in patients with muscle invasive bladder cancer.

GSTM1-null and GSTA1-low activity genotypes are associated with enhanced oxidative damage in bladder cancer

OBJECTIVES

To examine the association between gene variants of the detoxifying and antioxidant enzymes glutathione transferase M1 (GSTM1) and glutathione transferase A1 (GSTA1) and the extent of oxidative damage in patients with transitional cell carcinoma (TCC) of the urinary bladder.

METHODS

GSTM1 deletion polymorphism was identified by polymerase chain reaction, and the restriction fragment length polymorphism method was used for the single nucleotide polymorphism of GSTA1. Enzyme immunoassay was used to determine markers of DNA (8-hydroxy-2′-deoxyguanosine, 8-OHdG) and lipid (8-epiprostaglandin F2α) oxidative damage in the urine of 80 TCC patients and 60 age-matched controls.

RESULTS

Urinary 8-OHdG and 8-epi-prostaglandin F2α concentrations in TCC patients were significantly higher than in controls (P=0.043 and 0.001, respectively). GSTM1 and GSTA1 polymorphisms influence vulnerability to both DNA and lipid oxidation, with the GSTM1-null gene variant having a more pronounced effect. A significant effect of combined GSTM1 and GSTA1 genotypes on the extent of oxidative damage was found only for 8-OHdG (P=0.018). In addition, TCC patients with the most malignant tumors exhibited significantly higher frequencies of GSTM1-null or GSTA1-low activity genotypes, associated with a twofold increase in urinary 8-OHdG concentration (P=0.044).

CONCLUSIONS

Our results suggest that absent GSTM1 or reduced GSTA1 antioxidant activity may increase the accumulation of oxidative DNA damage, thereby contributing to the malignant potential of TCC.

Glutathione S-transferase P1 gene polymorphism and bladder cancer susceptibility: an updated analysis

Studies investigating the association between glutathione S-transferase P1 (GSTP1) gene polymorphism and bladder cancer (BC) risk have reported conflicting results. In order to clarify the effect of GSTP1 polymorphism on the BC susceptibility, we conducted an updated system review of published epidemiology studies to provide more precise evidence. We performed a systematic search of PubMed, EMBASE, and China National Knowledge Infrastructure (CNKI). 20 studies with 4,428 BC cases and 5,457 controls were identified. The combined analyses based on all studies showed that there was a significant difference in the genotype distribution in GSTP1(A313G) polymorphism between BC cases and controls not only in Asians (GG vs. AA + AG, OR = 1.59, 95 % CI = 1.01-2.51) but also in Caucasians (GG vs. AA + AG, OR = 1.51, 95 % CI = 1.11-2.06). Upon stratification for smoking status, we observed no statistically significant difference in genotype distribution of GSTP1 in ever-smokers. Combination of the high-risk genotypes (GSTM1 null + GSTT1 null + GSTP1 313 A/G or G/G) demonstrated further increase in the BC risk (OR = 6.64, 95 %CI = 3.63-12.16). This meta-analysis suggests that GSTP1 313 G/G polymorphism is a strong predisposing risk factor for BC.

Co-localization of GSTP1 and JNK in transitional cell carcinoma of urinary bladder

Transitional cell carcinoma (TCC) of urinary bladder belongs to glutathione S-transferase P1 (GSTP1) overexpressing tumors. Upregulated GSTP1 in TCC is related to apoptosis inhibition. This antiapoptotic effects of GSTP1 might be mediated through protein:protein interaction with c-Jun NH₂ -terminal kinase (JNK). Herein, we analyzed whether a direct link between GSTP1 and JNK exists in TCC. The presence of GSTP1/JNK complexes was analyzed by immunoprecipitation and Western blotting in 20 TCC specimens, obtained after surgery. Co-localization of GSTP1 and JNK was also investigated in the 5637 TCC cell line by immunofluorescence confocal microscopy. By means of immunoprecipitation we show for the first time the presence of GSTP1/JNK complexes in all TCC samples studied. A co-localization of GSTP1 and JNK was also demonstrated in the 5637 TCC cell line by means of confocal microscopy. Protein-protein interactions, together with co-localization between GSTP1 and JNK provide evidence that GSTP1 most probably inhibits apoptosis in TCC cells by non-covalent binding to JNK.