Simultaneous characterization of glutathione S-transferase M1 and T1 polymorphisms by polymerase chain reaction in American whites and blacks

Association of Genetic Polymorphisms in Oxidative Stress and Inflammation Pathways with Glaucoma Risk and Phenotype

Oxidative stress and neuroinflammation are involved in the pathogenesis and progression of glaucoma. Our aim was to evaluate the impact of selected single-nucleotide polymorphisms in inflammation and oxidative stress genes on the risk of glaucoma, the patients’ clinical characteristics and the glaucoma phenotype. In total, 307 patients with primary open-angle glaucoma or ocular hypertension were enrolled. The control group included 339 healthy Slovenian blood donors. DNA was isolated from peripheral blood. Genotyping was performed for SOD2 rs4880, CAT rs1001179, GPX1 rs1050450, GSTP1 rs1695, GSTM1 gene deletion, GSTT1 gene deletion, IL1B rs1143623, IL1B rs16944, IL6 rs1800795 and TNF rs1800629. We found a nominally significant association of GSTM1 gene deletion with decreased risk of ocular hypertension and a protective role of IL1B rs16944 and IL6 rs1800629 in the risk of glaucoma. The CT and TT genotypes of GPX1 rs1050450 were significantly associated with advanced disease, lower intraocular pressure and a larger vertical cup–disc ratio. In conclusion, genetic variability in IL1B and IL6 may be associated with glaucoma risk, while GPX and TNF may be associated with the glaucoma phenotype. In the future, improved knowledge of these pathways has the potential for new strategies and personalised treatment of glaucoma.

The role of polymorphisms in glutathione-related genes in asbestos-related diseases

BACKGROUND

The study investigated the influence of GCLC, GCLM, GSTM1, GSTT1 and GSTP1 polymorphisms, as well as the influence of interactions between polymorphism and interactions between polymorphisms and asbestos exposure, on the risk of developing pleural plaques, asbestosis and malignant mesothelioma (MM).

SUBJECTS AND METHODS

The cross sectional study included 940 asbestos-exposed subjects, among them 390 subjects with pleural plaques, 147 subjects with asbestosis, 225 subjects with MM and 178 subjects with no asbestos-related disease. GCLC rs17883901, GCLM rs41303970, GSTM1 null, GSTT1 null, GSTP1 rs1695 and GSTP1 rs1138272 genotypes were determined using PCR based methods. In statistical analysis, logistic regression was used.

RESULTS

GSTT1 null genotype was associated with the decreased risk for pleural plaques (OR = 0.63; 95% CI = 0.40-0.98; p = 0.026) and asbestosis (OR = 0.51; 95% CI = 0.28-0.93; p = 0.028), but not for MM. A positive association was found between GSTP1 rs1695 AG + GG vs. AA genotypes for MM when compared to pleural plaques (OR = 1.39; 95% CI = 1.00-1.94; p = 0.049). The interactions between different polymorphisms showed no significant influence on the risk of investigated asbestos-related diseases. The interaction between GSTT1 null polymorphism and asbestos exposure decreased the MM risk (OR = 0.17; 95% CI = 0.03-0.85; p = 0.031).

CONCLUSIONS

Our findings suggest that GSTT1 null genotype may be associated with a decreased risk for pleural plaques and asbestosis, may modify the association between asbestos exposure and MM and may consequently act protectively on MM risk. This study also revealed a protective effect of the interaction between GSTP1 rs1695 polymorphism and asbestos exposure on MM risk.

Evaluation of glutathione S-transferase polymorphism in Iranian patients with type 2 diabetic microangiopathy

Background

Overproduction of reactive oxygen species as a result of hyperglycemia in diabetes mellitus leads to microvascular complications. Glutathione S-transferases play important detoxifying roles with antioxidant potentials. This study aimed to assess whether the glutathione S-transferase M1 and T1 genotypes were associated with type 2 diabetes mellitus microangiopathic complications in the Iranian population.

Results

In this case-control study, the frequencies of null GSTM1 and GSTT1 genotypes were 4/72 (5.56%) and 12/72 (16.67%) respectively, in uncomplicated DM group. The frequencies of null GSTM1 and GSTT1 genotype in complicated DM group were 16/134 (11.94%) and 37/134 (27.61%), respectively. The proportion of GSTM1 null genotypes was higher in diabetic nephropathy compared to non-nephropathy (19.3% vs. 6.04 %, P = 0.006). At GSTT1 locus, patients with diabetic peripheral neuropathy had a higher frequency of deletion compared to those of without neuropathy (30.39% vs. 23.49%) (P = 0.02).

Conclusion

Selective polymorphisms encoding GSTM1 and GSTT1genes may prove useful as genetic markers to recognize individuals with an increased trend in developing diabetic nephropathy and neuropathy, respectively. This will help better identify individuals at higher risk toward microvascular complications of type 2 diabetes due to genetic susceptibility.

Pharmacogenomic markers of glucocorticoid response in the initial phase of remission induction therapy in childhood acute lymphoblastic leukemia

Background

Response to glucocorticoid (GC) monotherapy in the initial phase of remission induction treatment in childhood acute lymphoblastic leukemia (ALL) represents important biomarker of prognosis and outcome. We aimed to study variants in several pharmacogenes (NR3C1, GSTs and ABCB1) that could contribute to improvement of GC response through personalization of GC therapy.

Methods

Retrospective study enrolling 122 ALL patients was carried out to analyze variants of NR3C1 (rs33389, rs33388 and rs6198), GSTT1 (null genotype), GSTM1 (null genotype), GSTP1 (rs1695 and rs1138272) and ABCB1 (rs1128503, rs2032582 and rs1045642) genes using PCR-based methodology. The marker of GC response was blast count per microliter of peripheral blood on treatment day 8. We carried out analysis in which cut-off value for GC response was 1000 (according to Berlin-Frankfurt-Munster [BFM] protocol), as well as 100 or 0 blasts per microliter.

Results

Carriers of rare NR3C1 rs6198 GG genotype were more likely to have blast count over 1000, than the non-carriers (p = 0.030). NR3C1 CAA (rs33389-rs33388-rs6198) haplotype was associated with blast number below 1000 (p = 0.030). GSTP1 GC haplotype carriers were more likely to have blast number below 1000 (p = 0.036), below 100 (p = 0.028) and to be blast negative (p = 0.054), while GSTP1 GT haplotype and rs1138272 T allele carriers were more likely to be blasts positive (p = 0.034 and p = 0.024, respectively). ABCB1 CGT (rs1128503-rs2032582-rs1045642) haplotype carriers were more likely to be blast positive (p = 0.018).

Conclusions

Our results have shown that NR3C1 rs6198 variant and GSTP1 rs1695-rs1138272 haplotype are the most promising pharmacogenomic markers of GC response in ALL patients.

Glutathione S-Transferase M1 and T1 Gene Deletions and Susceptibility to Acute Lymphoblastic Leukemia (ALL) in adults

Objective:

Biotransformation of xenobiotics are critical for their metabolism and removal from the body which is carried out by xenobiotic metabolizing enzymes. Individuals carrying variants of genes that encode these enzymes have an altered ability to metabolize xenobiotics which may lead to an increased risk of acute lymphoblastic leukemia. The current study aimed to investigate the impact of GSTM1 and GSTT1 gene deletions in causing predisposition to adult ALL.

Methods:

The current case-control study involved 62 adult ALL patients and 62 age and gender matched healthy controls. Whole blood samples processed with standard phenol chloroform protocol for DNA isolation were genotyped using multiplex PCR approach for simultaneous identification of GSTM1 and GSTT1 deletions. The genotype frequency obtained for patients was compared to controls using odds ratio and chi-square.

Results:

The null genotype frequency of GSTM1 and GSTT1 in a group of adult ALL patients from Pakistan were 47% and 11% respectively. Deletion of GSTM1 and GSTT1 did not show statistically significant association with adult ALL (p=0.86 and p=0.35 respectively). The combined GSTM1/GSTT1 deletion was observed in 2% patients and was not significantly associated with ALL in adults (p=0.85).

Conclusions:

The results reveal that homozygous null polymorphism of GSTM1 and GSTT1genes does not influence ALL susceptibility among adult patients. Cancer susceptibility associated with GST polymorphism varies with ethnic and geographic differences. Therefore, further investigation on different populations is needed to understand the role of these genetic variations in modifying adult ALL risk.

Association of Glutathione S-Transferase Polymorphisms with Dietary Composition but Not Anthropometry in Obese as Well as Nonobese Individuals

OBJECTIVES

Glutathione S-transferases (GSTs) are detoxifying enzymes for a number of substrates, including some food compounds. Selected GST polymorphisms have been proven to significantly affect enzymatic activity; however, it is unclear whether this altered metabolism influences dietary composition. The objective of this study was to locate the correlation between GST polymorphisms and selected nutritional parameters, namely, fiber and vitamin C intake.

METHODS

This study was conducted on a cohort of 472 individuals (mean age 45.26 years; mean body mass index [BMI] 32.36) from the South Moravian region of the Czech Republic. Basic anthropometrical parameters were measured and no association was found for the selected polymorphisms. Polymorphisms in GSTA1, GSTM1, and GSTT1 were genotyped using a polymerase chain reaction (PCR)-based methodology. Food intake was monitored using a self-administered 7-day questionnaire that was subsequently analyzed with a special focus on vitamin C intake, fiber intake, and total energy intake.

RESULTS

For GSTA1 and GSTM1 polymorphisms, an association was observed with fiber intake. Though no association was found with vitamin C intake, mean vitamin C intake was found to be higher than recommended daily values. No association was found with either daily energy intake or anthropometric parameters.

CONCLUSION

Based on our results, GST polymorphisms seem to affect dietary composition; however, they have no effect on total energy intake or any association with obesity.

The Role of Oxidative Stress in Diabetic Neuropathy: Generation of Free Radical Species in the Glycation Reaction and Gene Polymorphisms Encoding Antioxidant Enzymes to Genetic Susceptibility to Diabetic Neuropathy in Population of Type I Diabetic Patients

Diabetic neuropathy (DN) represents the main cause of morbidity and mortality among diabetic patients. Clinical data support the conclusion that the severity of DN is related to the frequency and duration of hyperglycemic periods. The presented experimental and clinical evidences propose that changes in cellular function resulting in oxidative stress act as a leading factor in the development and progression of DN. Hyperglycemia- and dyslipidemia-driven oxidative stress is a major contributor, enhanced by advanced glycation end product (AGE) formation and polyol pathway activation. There are several polymorphous pathways that lead to oxidative stress in the peripheral nervous system in chronic hyperglycemia. This article demonstrates the origin of oxidative stress derived from glycation reactions and genetic variations within the antioxidant genes which could be implicated in the pathogenesis of DN. In the diabetic state, unchecked superoxide accumulation and resultant increases in polyol pathway activity, AGEs accumulation, protein kinase C activity, and hexosamine flux trigger a feed-forward system of progressive cellular dysfunction. In nerve, this confluence of metabolic and vascular disturbances leads to impaired neural function and loss of neurotrophic support, and over the long term, can mediate apoptosis of neurons and Schwann cells, the glial cells of the peripheral nervous system. In this article, we consider AGE-mediated reactive oxygen species (ROS) generation as a pathogenesis factor in the development of DN. It is likely that oxidative modification of proteins and other biomolecules might be the consequence of local generation of superoxide on the interaction of the residues of L-lysine (and probably other amino acids) with α-ketoaldehydes. This phenomenon of non-enzymatic superoxide generation might be an element of autocatalytic intensification of pathophysiological action of carbonyl stress. Glyoxal and methylglyoxal formed during metabolic pathway are detoxified by the glyoxalase system with reduced glutathione as co-factor. The concentration of reduced glutathione may be decreased by oxidative stress and by decreased in situ glutathione reductase activity in diabetes mellitus. Genetic variations within the antioxidant genes therefore could be implicated in the pathogenesis of DN. In this work, the supporting data about the association between the -262T > C polymorphism of the catalase (CAT) gene and DN were shown. The -262TT genotype of the CAT gene was significantly associated with higher erythrocyte catalase activity in blood of DN patients compared to the -262CC genotype (17.8 ± 2.7 × 10(4) IU/g Hb vs. 13.5 ± 3.2 × 10(4) IU/g Hb, P = 0.0022). The role of these factors in the development of diabetic complications and the prospective prevention of DN by supplementation in formulations of transglycating imidazole-containing peptide-based antioxidants (non-hydrolyzed carnosine, carcinine, n-acetylcarcinine) scavenging ROS in the glycation reaction, modifying the activity of enzymic and non-enzymic antioxidant defenses that participate in metabolic processes with ability of controlling at transcriptional levels the differential expression of several genes encoding antioxidant enzymes inherent to DN in Type I Diabetic patients, now deserve investigation.

A comparison of 12-gene colon cancer assay gene expression in African American and Caucasian patients with stage II colon cancer

Background

African American (AA) colon cancer patients have a worse prognosis than Caucasian (CA) colon cancer patients, however, reasons for this disparity are not well understood. To determine if tumor biology might contribute to differential prognosis, we measured recurrence risk and gene expression using the Oncotype DX® Colon Cancer Assay (12-gene assay) and compared the Recurrence Score results and gene expression profiles between AA patients and CA patients with stage II colon cancer.

Methods

We retrieved demographic, clinical, and archived tumor tissues from stage II colon cancer patients at four institutions. The 12-gene assay and mismatch repair (MMR) status were performed by Genomic Health (Redwood City, California). Student’s t-test and the Wilcoxon rank sum test were used to compare Recurrence Score data and gene expression data from AA and CA patients (SAS Enterprise Guide 5.1).

Results

Samples from 122 AA and 122 CA patients were analyzed. There were 118 women (63 AA, 55 CA) and 126 men (59 AA, 67 CA). Median age was 66 years for AA patients and 68 for CA patients. Age, gender, year of surgery, pathologic T-stage, tumor location, the number of lymph nodes examined, lymphovascular invasion, and MMR status were not significantly different between groups (p = 0.93). The mean Recurrence Score result for AA patients (27.9 ± 12.8) and CA patients (28.1 ± 11.8) was not significantly different and the proportions of patients with high Recurrence Score values (≥41) were similar between the groups (17/122 AA; 15/122 CA). None of the gene expression variables, either single genes or gene groups (cell cycle group, stromal group, BGN1, FAP, INHBA1, Ki67, MYBL2, cMYC and GADD45B), was significantly different between the racial groups. After controlling for clinical and pathologic covariates, the means and distributions of Recurrence Score results and gene expression profiles showed no statistically significant difference between patient groups.

Conclusion

The distribution of Recurrence Score results and gene expression data was similar in a cohort of AA and CA patients with stage II colon cancer and similar clinical characteristics, suggesting that tumor biology, as represented by the 12-gene assay, did not differ between patient groups.

Analyses of Genetic Variations of Glutathione S-Transferase Mu1 and Theta1 Genes in Bangladeshi Tannery Workers and Healthy Controls

Glutathione S-transferases (GSTs) belong to a group of multigene detoxification enzymes, which defend cells against oxidative stress. Tannery workers are at risk of oxidative damage that is usually detoxified by GSTs. This study investigated the genotypic frequencies of GST Mu1 (GSTM1) and GST Theta1 (GSTT1) in Bangladeshi tannery workers and healthy controls followed by their status of oxidative stress and total GST activity. Of the 188 individuals, 50.0% had both GSTM1 and GSTT1 (+/+), 12.2% had GSTM1 (+/-), 31.4% had GSTT1 (-/+) alleles, and 6.4% had null genotypes (-/-) with respect to both GSTM1 and GSTT1 alleles. Among 109 healthy controls, 54.1% were double positive, 9.2% had GSTM1 allele, 32.1% had GSTT1 allele, and 4.6% had null genotypes. Out of 79 tannery workers, 44.3% were +/+, 16.8% were +/-, 30.5% were -/+, and 8.4% were -/-. Though the polymorphic genotypes or allelic variants of GSTM1 and GSTT1 were distributed among the study subjects with different frequencies, the differences between the study groups were not statistically significant. GST activity did not vary significantly between the two groups and also among different genotypes while level of lipid peroxidation was significantly higher in tannery workers compared to controls irrespective of their GST genotypes.

Improvement of a predictive model in ovarian cancer patients submitted to platinum-based chemotherapy: implications of a GST activity profile

PURPOSE

The success of chemotherapy in ovarian cancer (OC) is directly associated with the broad variability in platinum response, with implications in patients survival. This heterogeneous response might result from inter-individual variations in the platinum-detoxification pathway due to the expression of glutathione-S-transferase (GST) enzymes. We hypothesized that GSTM1 and GSTT1 polymorphisms might have an impact as prognostic and predictive determinants for OC.

METHODS

We conducted a hospital-based study in a cohort of OC patients submitted to platinum-based chemotherapy. GSTM1 and GSTT1 genotypes were determined by multiplex PCR.

RESULTS

GSTM1-null genotype patients presented a significantly longer 5-year survival and an improved time to progression when compared with GSTM1-wt genotype patients (log-rank test, P = 0.001 and P = 0.013, respectively). Multivariate Cox regression analysis indicates that the inclusion of genetic information regarding GSTM1 polymorphism increased the predictive ability of risk of death after OC platinum-based chemotherapy (c-index from 0.712 to 0.833). Namely, residual disease (HR, 4.90; P = 0.016) and GSTM1-wt genotype emerged as more important predictors of risk of death (HR, 2.29; P = 0.039; P = 0.036 after bootstrap). No similar effect on survival was observed regarding GSTT1 polymorphism, and there were no statistically significant differences between GSTM1 and GSTT1 genotypes and the assessed patients' clinical-pathological characteristics.

CONCLUSION

GSTM1 polymorphism seems to have an impact in OC prognosis as it predicts a better response to platinum-based chemotherapy and hence an improved survival. The characterization of the GSTM1 genetic profile might be a useful molecular tool and a putative genetic marker for OC clinical outcome.

[Molecular epidemiology study in Xuanwei: the relationship among coal type, genotype and lung cancer risk]

背景与目的

已有的研究证明：宣威是我国农村肺癌死亡率最高的地区，肺癌危险与室内燃烧烟煤产生的多环芳烃（polycyclic aromatic hydrocarbons, PAHs）有关，肺癌发病具有明显的地域性差别和家族聚集性。本研究从分子流行病学角度探索宣威肺癌风险的危险因素及与发病机理有关的基因型和燃煤类型。

方法

运用两个基于人群的病例对照研究，开展问卷调查，同时采集口腔细胞和痰等生物样品，提取DNA。应用PCR法检测GST超家族、AKR超家族和OGG1等基因型。通过Logistic回归分析煤种、基因型与肺癌风险的关联。

结果

与燃用无烟煤或木柴的研究对象相比，家用来宾烟煤的肺癌风险比数比（odds ratio, OR）值高达24.8，其次为龙潭（OR=11.6）、宝山（OR=6.0）、龙场（OR=4.1）、羊场（OR=3.8）等；燃用同种烟煤的男女肺癌风险相似。对于GSTM1缺失、AKR1C3（Ex1-70C > G）、OGG1（Ex6-315C > G）基因型，肺癌风险明显增高，且具统计学意义[OR（95%CI）分别为2.3（1.3-4.2）、1.8（1.0-3.5）和1.9（1.1-3.3）]。与家用烟煤量小且具GSTM1阳性的研究对象相比，用量大且GSTM1缺失的研究对象肺癌风险更高，女性OR为4.9（1.3-18.2），男性OR为2.7（1.0-7.4）。但对于AKR1C3（Ex1-70C > G）和OGG1（Ex6-315C > G），仅观察到女性肺癌风险的明显增高，OR分别为12.9（2.2-107.8）和5.7（1.1-34.2）。

结论

宣威不同煤种的肺癌风险有很大差异，但暴露于相同煤种的男性与女性肺癌风险相似。GSTM1缺失基因型与肺癌风险增高有关联。AKR1C3与OGG1这2种基因型与肺癌风险有关联，且在烟煤使用量高的女性中肺癌风险更高。

Common polymorphisms in antioxidant genes are associated with diabetic nephropathy in Type 2 diabetes patients

AIM

To investigate if antioxidative genes' polymorphisms influence the risk for Type 2 diabetes (T2D) complications.

MATERIALS & METHODS

In total, 181 T2D patients were genotyped for SOD2, CAT, GPX1, GSTP1, GSTM1*0, GSTT1*0, GCLC and GCLM.

RESULTS

After adjustment for duration of T2D, CAT rs1001179 and GSTP1 rs1138272 showed strongest association with risk for end-stage kidney failure (p = 0.005 and p = 0.049, respectively). In patients without end-stage kidney failure CAT rs1001179 influenced urea levels (p = 0.003), while GSTP1 rs1695 and GSTP1 haplotypes influenced the risk of moderately increased albuminuria (p = 0.024 and p = 0.014, respectively).

CONCLUSION

Common CAT and GSTP1 polymorphisms could be used to identify T2D patients at an increased risk for developing end-stage kidney failure.

Interaction between GSTT1 and GSTP1 allele variants as a risk modulating-factor for autism spectrum disorders

We investigated the role of glutathione S-transferase (GST) genes in Autism Spectrum Disorder (ASD). We used data from 111 pairs of age- and sex-matched ASD cases and typically developing (TD) controls between 2-8 years of age from Jamaica to investigate the role of GST pi 1 (GSTP1), GST theta 1 (GSTT1), and GST mu 1 (GSTM1) polymorphisms in susceptibility to ASD. In univariable conditional logistic regression models we did not observe significant associations between ASD status and GSTT1, GSTM1, or GSTP1 genotype (all P > 0.15). However, in multivariable conditional logistic regression models, we identified a significant interaction between GSTP1 and GSTT1 in relation to ASD. Specifically, in children heterozygous for the GSTP1 Ile105Val polymorphism, the odds of ASD was significantly higher in those with the null GSTT1 genotype than those with the other genotypes [Matched Odds Ratio (MOR) = 2.97, 95% CI (1.09, 8.01), P = 0.03]. Replication in other populations is warranted.

GSTM1, GSTT1, and NQO1 polymorphisms in cervical carcinogenesis

The aim of the study is to investigate the clinical significance of glutathione-S-transferase GSTM1, GSTT1, and NQO1 c.609C>T (rs1800566) genetic polymorphisms in cervical carcinogenesis. GSTM1, GSTT1, and NQO1 polymorphisms together with human papillomavirus (HPV) types were examined in a total of 192 cervical smear in exfoliated cervical cell samples using polymerase chain reaction (PCR) system and real-time polymerase chain reaction (PCR) system. The 19 patients with high-grade squamous intraepithelial lesion had statistically higher frequency of null GSTT1 genotype than 9 with low-grade squamous intraepithelial lesion (LSIL) among the 67 patients with high-risk HPV (P = 0.024). The 24 patients with HSIL had also statistically higher frequency of NQO1 (CT+TT) genotype than 14 with LSIL among the 67 patients with high-risk HPV (P = 0.024). GSTT1 null and NQO1 genotype in cervical cell samples may be associated with more severe precancerous lesions of the cervix in a Japanese population.

The association of GSTM1 and GSTT1 polymorphisms with squamous cell carcinoma of cervix in Pakistan

Gene deletions in GSTM1 and GSTT1 may result in tempering the activation and detoxification of several carcinogens and thereby may increase the risk of cancer pre-disposition. This study aims to investigate the clinical impact of glutathione-S-transferase GSTM1 and GSTT1 polymorphisms on squamous cell carcinoma of cervix (SCCA).The GSTM1 and GSTT1 polymorphisms were analyzed in cervical cancer patients and healthy controls. Touch down multiplex polymerase chain reaction (PCR) strategy was adopted for genotyping of GSTM1 and GSTT1 polymorphisms. The null genotype of GSTM1 exhibited a significantly higher percentage in patients with SCCA (74 %) than in the control group (34.0 %). However, no significant difference was observed in the null genotype of GSTT1 among SCC patients and healthy subjects, respectively. GSTM1 exhibited a significant association with increased risk of squamous cell carcinoma (p < 0.001). The odds ratio for the GSTM1 null genotype was also calculated (odds ratio 3.7484; 95 % confidence interval 1.6562-84834). This suggests that GSTM1 null genotype in cervical cell samples may be associated with more severe precancerous lesions of the cervix.

Role of metabolic genes in blood arsenic concentrations of Jamaican children with and without autism spectrum disorder

Arsenic is a toxic metalloid with known adverse effects on human health. Glutathione-S-transferase (GST) genes, including GSTT1, GSTP1, and GSTM1, play a major role in detoxification and metabolism of xenobiotics. We investigated the association between GST genotypes and whole blood arsenic concentrations (BASC) in Jamaican children with and without autism spectrum disorder (ASD). We used data from 100 ASD cases and their 1:1 age- and sex-matched typically developing (TD) controls (age 2-8 years) from Jamaica. Using log-transformed BASC as the dependent variable in a General Linear Model, we observed a significant interaction between GSTP1 and ASD case status while controlling for several confounding variables. However, for GSTT1 and GSTM1 we did not observe any significant associations with BASC. Our findings indicate that TD children who had the Ile/Ile or Ile/Val genotype for GSTP1 had a significantly higher geometric mean BASC than those with genotype Val/Val (3.67 µg/L vs. 2.69 µg/L, p < 0.01). Although, among the ASD cases, this difference was not statistically significant, the direction of the observed difference was consistent with that of the TD control children. These findings suggest a possible role of GSTP1 in the detoxification of arsenic.

Fetal sex and race modify the predictors of fetal growth

The objective of this study is unknown if fetal sex and race modify the impact of maternal pre-pregnancy body mass index (BMI), and smoking on fetal growth. The authors studied markers of fetal growth in singleton offspring of 8,801 primiparous, normotensive women, enrolled in the Collaborative Perinatal Project. The authors tested for departures from additivity between sex/race and each predictor. The head-to-chest circumference ratio (HCC) decreased more, while birthweight and ponderal index (PI) increased more for each 1 kg/m(2) increase in pre-pregnancy BMI among term females versus males (P = 0.07, P < 0.01 and P = 0.08, interaction respectively). For term offspring of White compared with Black women, smoking independent of "dose" was associated with larger reductions in growth (165 g vs. 68 g reduction in birthweight, P < 0.01, interaction), greater reduction in fetal placental ratio (P < 0.01, interaction), PI (P < 0.01, interaction), and greater increase in HCC (P = 0.02), respectively. The association of BMI and smoking with fetal size appeared to be reversed in term versus preterm infants. Our study provides evidence that the associations of pre-pregnancy BMI and smoking are not constant across sex and race. This finding may be relevant to sex and race differences in neonatal and long term health outcomes.

A multiplex polymerase chain reaction method for the simultaneous detection of GSTM1, GSTT1, and GSTP1 polymorphisms

BACKGROUND

Glutathione S-transferases (GSTs) play an important role in the detoxification of a wide variety of toxicants. Among GSTs, GSTM1 and GSTT1 polymorphic deletions and the GSTP1 Ile105Val polymorphism were often studied in combination in many diseases because of their additive effects, but they were usually genotyped by two separate methods.

AIM

The purpose of the present study was to develop a simple and reliable method to simultaneously detect these three polymorphisms.

METHODS

The three polymorphisms of 259 volunteers were genotyped using a multiplex polymerase chain reaction (PCR) method based on a tetra-primer amplification refractory mutation system-PCR (T-ARMS-PCR), and the results were validated by multiplex PCR for GSTM1 and GSTT1 polymorphisms and DNA sequencing of the GSTP1 Ile105Val polymorphism, respectively.

RESULTS

The multiplex PCR method of GSTM1, GSTT1, and GSTP1 polymorphisms based on T-ARMS-PCR can simultaneous detect the three polymorphisms in a single PCR. The results of this method are in perfect accord with the results of the multiplex PCR method of determining GSTM1, GSTT1 polymorphisms, and DNA sequencing of GSTP1 Ile105Val polymorphism.

CONCLUSION

The novel multiplex PCR method of GSTM1, GSTT1, and GSTP1 polymorphisms is simple, fast, low-cost, and reliable for the simultaneous detection of GSTM1, GSTT1, and GSTP1 Ile105Val polymorphisms.

Polymorphisms of glutathione-S-transferases M1, T1, P1 and susceptibility to colorectal cancer in a sample of the Tunisian population

In this study, we investigated the associations of polymorphisms in glutathione-S-transferases (GSTs) genes that are GSTM1, GSTT1, and GSTP1, with sporadic colorectal cancer (CRC). Hundred and fifty patients with CRC and 128 healthy controls were genotyped. DNA was isolated from blood samples. Polymorphisms were assessed by polymerase chain reaction-restriction fragment length polymorphism-based methods and polymerase chain reaction multiplex. Logistic regression analyses showed significant risk for CRC associated with GSTP1 homozygotes for Val-105 (OR 4.82; 95 % CI 1.97-11.80) or for individuals who possessed at least one Val-105 allele (OR 2.54; 95 % CI 1.751-3.703). There were no statistically significant differences in the frequency of GSTM1- and GSTT1-null genotypes (p > 0.05). The GSTM1-null was found in 70.47 % of all cases and 70.07 % of controls (OR 0.61; 95 % CI 0.33-1.12). The GSTT1-null genotype was found in 38.77 % of cases and 49.22 % of controls (OR 1.53; 95 % CI 0.94-2.47). No effect of any genotype for GSTM1 and GSTT1 on CRC was detected. But then an association between the polymorphism of the GSTP1 and the CRC susceptibility was detected.

Parental smoking and risk of childhood brain tumors by functional polymorphisms in polycyclic aromatic hydrocarbon metabolism genes

BACKGROUND

A recent meta-analysis suggested an association between exposure to paternal smoking during pregnancy and childhood brain tumor risk, but no studies have evaluated whether this association differs by polymorphisms in genes that metabolize tobacco-smoke chemicals.

METHODS

We assessed 9 functional polymorphisms in 6 genes that affect the metabolism of polycyclic aromatic hydrocarbons (PAH) to evaluate potential interactions with parental smoking during pregnancy in a population-based case-control study of childhood brain tumors. Cases (N = 202) were ≤10 years old, diagnosed from 1984-1991 and identified in three Surveillance, Epidemiology, and End Results (SEER) registries in the western U.S. Controls in the same regions (N = 286) were frequency matched by age, sex, and study center. DNA for genotyping was obtained from archived newborn dried blood spots.

RESULTS

We found positive interaction odds ratios (ORs) for both maternal and paternal smoking during pregnancy, EPHX1 H139R, and childhood brain tumors (P(interaction) = 0.02; 0.10), such that children with the high-risk (greater PAH activation) genotype were at a higher risk of brain tumors relative to children with the low-risk genotype when exposed to tobacco smoke during pregnancy. A dose-response pattern for paternal smoking was observed among children with the EPHX1 H139R high-risk genotype only (OR(no exposure) = 1.0; OR(≤3 hours/day) = 1.32, 95% CI: 0.52-3.34; OR(>3 hours/day )= 3.18, 95% CI: 0.92-11.0; P(trend )= 0.07).

CONCLUSION

Parental smoking during pregnancy may be a risk factor for childhood brain tumors among genetically susceptible children who more rapidly activate PAH in tobacco smoke.

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.

Genetic polymorphisms of GSTM1 and GSTT1 genes in Delhi and comparison with other Indian and global populations

The glutathione S-transferases (GSTs) are involved in the metabolism of many xenobiotics, including an array of environmental carcinogens, pollutants, and drugs. Genetic polymorphisms in these genes may lead to inter- individual variation in susceptibility to various diseases. In the present study, GSTM1 and GSTT1 polymorphisms were analysed using a multiplex polymerase chain reaction in 500 normal individuals from Delhi. The frequency of individuals with GSTM1 and GSTT1 null genotypes were 168 (33.6%) and 62 (12.4%) respectively, and 54 (10.8%) were having homozygous null genotype for both the genes GSTM1 and GSTT1 simultaneously. The studied population was compared with reported frequencies from other neighbouring state populations, as well as with those from other ethnic groups; Europeans, Blacks, and Asians. The prevalence of homozygous null GSTM1 genotype is significantly higher in Caucasians and Asians as compared to Indian population. The frequency of GSTT1 homozygous null genotypes is also significantly higher in blacks and Asians. We believe that due to large number of individuals in this study, our results are reliable estimates of the frequencies of the GSTM1, GSTT1 in Delhi. It would provide a basic database for future clinical and genetic studies pertaining to susceptibility and inconsistency in the response and/or toxicity to drugs known to be the substrates for GSTs.

GSTM1 and GSTT1 polymorphism and susceptibility to esophageal cancer in high- and low-risk regions of India

Glutathione transferases, a super family of dimeric phase II metabolic enzymes play a vital role in biotransformation of many substances. This study evaluates the influence of genetic polymorphism of GSTM1 and GSTT1 gene loci on esophageal cancer risk in Assam and Delhi from India. DNA from blood samples of esophageal cancer cases (203,112) and controls (286,150) from Assam and Delhi, respectively, were extracted. GSTM1 and GSTT1 polymorphisms were analyzed by multiplex PCR procedure. Differences in proportions were tested using Pearson's chi-square test with odds ratio (OR) and 95 % confidence interval (CI). Risk of esophageal cancer was approximately twice in individuals having homozygous GSTM1 (OR-2.1, 95 % CI, 1.44-3.13) and GSTT1 null genotypes (OR-1.7,95 % CI, 0.99-2.77) in Assam, and around three times in GSTT1 null genotype (OR-2.9, 95 % CI, 1.56-5.27) in Delhi population. GSTM1 null genotype seems to play a protective role (OR-0.7, 95 % CI, 0.39-1.27) in Delhi. A significant association of GSTM1 null genotype with esophageal cancer was observed in a younger age group in Assam (OR-2.7, 95 % CI, 1.48-5.01), and in Delhi population association was observed in smokers with GSTT1 null genotype (OR-2.5, 95 % CI, 1.04-6.07), and alcoholics having GSTM1 null genotype (OR-2.6, 95 % CI, 0.99-6.77). Significant association of GSTM1 null genotype in Assam was observed between cancer cases and controls in fermented betel nut chewers only (OR-2.8, 95 % CI, 1.19-6.72), whereas, smoking and alcohol failed to show any correlation with GSTM1/GSTT1 genotypes. Cancer development is not only due to exogenous or endogenous carcinogens but depends on their interaction with genes that are involved in the detoxification of these carcinogens.

Genetic polymorphisms of CYP2E1, GST, and NAT2 enzymes are not associated with risk of breast cancer in a sample of Lebanese women

Changes in the activity of drug metabolizing enzymes (DMEs) are potentially associated with cancer risk. This relationship is attributed to their involvement in the bioactivation of multiple procarcinogens or the metabolism of multiple substrates including an array of xenobiotics and environmental carcinogens. 326 Lebanese women of whom 99 were cancer free (controls) and 227 were diagnosed with breast cancer (cases) were included. Blood for DNA was collected and medical charts were reviewed. Three genotyping methods were employed including: (1) restriction fragment length polymorphism (RFLP) for CYP2E1*5B, CYP2E1*6, NAT2*5 and NAT2*6; (2) gel electrophoresis for GSTM1 and GSTT1; and (3) real-time PCR for GSTP1 Ile/Val polymorphism. We analyzed the relationship between genetic susceptibilities in selected xenobiotic metabolizing genes and breast cancer risk. Allele frequencies were fairly similar to previously reported values from neighboring populations with relevant migration routes. There were no statistically significant differences in the distribution of variant carcinogen metabolizing genes between cases and controls even after adjusting for age at diagnosis, menopausal status, smoking, and alcohol intake. Despite its limitations, this is the first study that assesses the role of genetic polymorphisms in DMEs with breast cancer in a sample of Lebanese women. Further studies are needed to determine the genetic predisposition and gene-environment interactions of breast cancer in this population.

Common polymorphisms in GSTM1, GSTT1, GSTP1, GSTA1 and susceptibility to colorectal cancer in the Central European population

Background

Central Europe presents with the highest incidence of sporadic colorectal cancer (CRC) worldwide. As sporadic CRC represents a typical multifactorial disease, it is characterized by intense interaction of the genetic background with the environment. Glutathione S-transferases could act as attractive susceptibility genes for CRC, as they are directly involved in conjugation between glutathione and chemotherapeutics, environmental pollutants and a wide spectrum of xenobiotics.

Methods

In this study, we investigated associations of polymorphisms in glutathione S-transferases (GSTs) genes, that is GSTA1, GSTT1, GSTM1 and GSTP1, with CRC in a total of 197 cases and 218 controls originating from the Czech Central European population. Polymorphisms were assessed by polymerase chain reaction/restriction fragment length polymorphism-based methods, allele-specific multiplex and allelic discrimination by real-time polymerase chain reaction.

Results

None of investigated polymorphisms showed any associations with CRC, with the exception of GSTP1; where the heterozygote genotype Ile105Val was associated with decreased risk of CRC (P = 0.043).

Conclusions

The frequencies observed in our study are in accordance with those from other European Caucasian populations. Based on our studies, examined variability in GST genes is not a major determinant of CRC susceptibility in the Central European population.

Childhood brain tumors and maternal cured meat consumption in pregnancy: differential effect by glutathione S-transferases

BACKGROUND

Some epidemiologic studies suggest that maternal consumption of cured meat during pregnancy may increase risk of brain tumors in offspring. We explored whether this possible association was modified by fetal genetic polymorphisms in genes coding for glutathione S-transferases (GSTs) that may inactivate nitroso compounds.

METHODS

We assessed six GST variants: GSTM1 null, GSTT1 null, GSTP1(I105V) (rs1695), GSTP1(A114V) (rs1138272), GSTM3*B (3-bp deletion), and GSTM3(A-63C) (rs1332018) within a population-based case-control study with data on maternal prenatal cured meat consumption (202 cases and 286 controls born in California or Washington, 1978-1990).

RESULTS

Risk of childhood brain tumor increased with increasing cured meat intake by the mother during pregnancy among children without GSTT1 [OR = 1.29; 95% confidence interval (95% CI), 1.07-1.57 for each increase in the frequency of consumption per week] or with potentially reduced GSTM3 (any -63C allele; OR = 1.14; 95% CI, 1.03-1.26), whereas no increased risk was observed among those with GSTT1 or presumably normal GSTM3 levels (interaction P = 0.01 for each).

CONCLUSIONS

Fetal ability to deactivate nitrosoureas may modify the association between childhood brain tumors and maternal prenatal consumption of cured meats.

IMPACT

These results support the hypothesis that maternal avoidance during pregnancy of sources of some nitroso compounds or their precursors may reduce risk of brain tumors in some children.

Variations in glutathione-S-transferase genes influence risk of chronic myeloid leukemia

Glutathione S-transferases (GSTs) are phase II enzymes that detoxify hazardous xenobiotics including carcinogens. Inter-individual variations in GSTM1 and GSTT1 loci have been associated with several types of cancer, including leukemias. In this study, we investigated the possible association between GSTM1 and GSTT1 polymorphisms and susceptibility to chronic myeloid leukemia (CML) in a Turkish population. In a case-control study, 106 CML patients and 190 healthy controls were evaluated for GSTM1 and GSTT1 polymorphisms. GSTM1 null (GSTM1(-)) genotype frequencies in CML cases and controls were 45.3% and 42.6%, respectively. GSTT1 null (GSTT1(-)) genotype frequencies were 44.3% and 18.4%, respectively. The frequency of the GSTT1(-) genotype among CML patients was significantly higher than in controls [odds ratio (OR) 3.53, 95% confidence interval (CI) 2.08-6.00; P < 0.0001]. Individuals with the GSTM1(-) genotype did not have increased risk of CML [OR: 1.11; 95% CI: 0.69-1.80; P = 0.714]. The combined GSTM1(-)/GSTT1(-) genotype was significantly associated with risk of CML compared to the GSTM1(+) /GSTT1(+) genotype which was most frequent in both cases and controls [OR: 9.47; 95% CI: 3.61-24.87]. Similar findings have only been obtained in Turkish and Indian populations but not elsewhere. The GSTM1(+) /GSTT1(-) genotype was associated with a 2.5-fold increased risk compared with the GSTM1(-)/GSTT1(+) genotype, the second most frequent genotype (OR; 2.46; 95% CI: 1.17, 5.20), suggesting a complex interaction between GSTM1 and GSTT1. Our results indicate an association between the GSTT1(-) genotype, either alone or in combination with GSTM1(-) genotype, and risk of CML, suggesting a possible interaction between GSTM1 and GSTT1. These findings, which are possibly restricted to Turkey and India, warrant further research.

Genetic Polymorphism of Cancer Susceptibility Genes and HPV Infection in Cervical Carcinogenesis

It is widely accepted that specific human papillomavirus (HPV) types are the central etiologic agent of cervical carcinogenesis. However, a number of infected women do not develop invasive lesions, suggesting that other environmental and host factors may play decisive roles in the persistence of HPV infection and further malignant conversion of cervical epithelium. Although many previous reports have focused on HPV and environmental factors, the role of host susceptibility to cervical carcinogenesis is largely unknown. Here, we review the findings of genetic association studies in cervical carcinogenesis with special reference to polymorphisms of glutathione-S-transferase (GST) isoforms, p53 codon 72, murine double-minute 2 homolog (MDM2) gene promoter 309, and FAS gene promoter -670 together with HPV types including our recent research results.

Glutathione S-transferase M1, T1, and P1 genotypes and breast cancer risk: a study in a Portuguese population

Glutathione S-transferases are a superfamily of multifunctional enzymes that play a key role in Phase II metabolism, detoxifying therapeutic drugs, and various carcinogens by conjugation with glutathione. We undertook a case-control study in Central-Eastern Portuguese population to evaluate the association of null genotype in GSTM1 and GSTT1 along with the polymorphism in GSTP1 (A/G) and susceptibility to breast cancer. The population sample consisted of 85 patients with histological diagnosis of breast cancer and 102 healthy women. Genomic DNA was extracted from blood samples, and genotyping analyses were performed by PCR-based methods. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated by unconditional logistic regression. We found a increased breast cancer risk associated with GSTM1 null genotype (OR = 3.597; 95% CI = 1.849-6.999; P = 0.0001) and GSTT1 (OR = 2.592; 95% CI = 1.432-4.690; P = 0.002), but the presence of valine alleles compared to isoleucine alleles in codon 105 in GSTP1 did not increase the risk of breast cancer development. The two-way combination of GSTM1 and GTTT1 null genotypes resulted in 8-fold increase for breast cancer risk (OR = 8.287; 95% CI = 3.124-21.980; P = 0.0001) and the three-way combination of GSTP1 105AA/AG and null genotypes for both GSTM1 and GSTT1 resulted in 5-fold increase for breast cancer risk (OR = 5.040; 95% CI = 1.392-18.248; P = 0.016). Our results suggest that GSTM1 and GSTT1 null genotype alone, both combined or combined with GSTP1 valine alleles, are associated with higher susceptibility to breast cancer development.

Genetic polymorphisms influence runners' responses to the dietary ingestion of antioxidant supplementation based on pequi oil (Caryocar brasiliense Camb.): a before-after study

Genes have been implicated in the levels of oxidative stress, lipids, CVD risk, immune reactivity, and performance. Pequi oil (Caryocar brasiliense) has shown anti-inflammatory and hypotensive effects, besides reducing exercise-induced DNA, tissue damages, and anisocytosis. Given that diet can interact with the human genome to influence health and disease, and because genetic variability can influence response to diet, we aim to investigate the influence of 12 gene polymorphisms on inflammatory markers, postprandial lipids, arterial pressure, and plasma lipid peroxidation of runners (N = 125), before and after 14 days of 400 mg pequi-oil supplementation, after races under closely comparable conditions. Arterial pressure was checked before races; blood samples were taken immediately after racing to perform leukogram and plateletgram, Tbars assay, lipid, and CRP dosages and genotyping. CAT, GST-M1/T1, CRP-G1059C, and MTHFR-C677T polymorphisms influenced post-pequi-oil responses in leukogram; Hp and MTHFR-C677T, in plateletgram; Hp, ACE, GSTT1, and MTHFR-A1298C, in lipid profile; MTHFR-A1298C, in C-reactive protein (CRP) levels; and Hp and MnSOD, in Tbars assay. Differences between ACE genotypes in leukogram and total cholesterol disappeared after pequi, and the same occurred for Hp and MnSOD in Tbars assay and for MTHFR-A1298C with CRP levels. Because genetic inheritance is one of the factors that drive atherosclerosis-related lipid abnormalities, results can contribute to a greater understanding of the influence of genetic polymorphisms in situations that push up free radicals. Knowledge is also expanded on how antioxidant supplementation affects an individual's genes and how athletic genetic makeup can affect the way a person responds to antioxidant supplements.

Glutathione S-transferase copy number variation alters lung gene expression

The glutathione S-transferase (GST) enzymes catalyse the conjugation of xenobiotics to glutathione. Based on reports that inherited copy number variations (CNVs) modulate some GST gene expression levels, and that the small airway epithelium (SAE) and alveolar macrophages (AMs) are involved early in the pathogenesis of smoking-induced lung disease, we asked: do germline CNVs modulate GST expression levels in SAE and AMs? Microarrays were used to survey GST gene expression and determine CNVs genotypes in SAE and AMs obtained by bronchoscopy from current smokers and nonsmokers. 26% of subjects were null for both GSTM1 alleles, with reduced GSTM1 mRNA levels seen in both SAE and AMs. 30% of subjects had homozygous deletions of GSTT1, with reduced mRNA levels in both tissues. Interestingly, GSTT2B exhibited homozygous deletion in the blood of 27% of subjects and was not expressed in SAE in the remainder of subjects, but was expressed in AMs of heterozygotes and wild-type subjects, proportionate to genotype. These data show a germline CNV-mediated linear relationship of genotype with expression level, suggesting minimal compensation of gene expression levels in heterozygotes, consistent with GST polymorphisms playing a role in the risk of smoking-associated, xenobiotic-induced lung disease.

GSTT1 and GSTM1 gene deletions are not associated with hepatotoxicity caused by antitubercular drugs

BACKGROUND AND OBJECTIVE

Susceptibility to antitubercular drug (ATD)-induced hepatotoxicity may be genetically mediated, with variant alleles of genes such as N-acetyltransferase (NAT2) and CYP2E1 reported as risk factors. Two studies of Asian populations have reported that GSTM1*0 ⁄ *0 (null) genotype was a likely predictor of hepatotoxicity, whereas another of a Caucasian population implicated GSTT1*0 ⁄ *0. We undertook a prospective case-control study to investigate whether GSTM*0 ⁄ *0 and GSTT1*0 ⁄ *0 were risk factors for ATD-induced hepatotoxicity.

METHODS

Pulmonary tuberculosis patients on isoniazid, rifampicin and pyrazinamide who developed hepatotoxicity using defined criteria were prospectively identified. These cases were then matched with at least one control subject on the same drugs but without hepatotoxicity. Genotyping for GSTM1 and GSTT1 was performed by multiplex PCR on genomic DNA. The odds ratios for the frequency of specific GSTM1 and GSTT1 homozygotes in the case and control subjects were calculated to test for association between the genotypes and hepatotoxicity.

RESULTS AND DISCUSSION

Hundred and fifty-one subjects (51 cases, 100 controls) were enrolled. Odds ratio for GSTM1 null genotype was 1.00 (95% CI 0.51-1.97) and GSTT1 null was 2.02 (95% CI 0.39-10.39), respectively, showing that these genotypes are not associated with hepatotoxicity.

CONCLUSION

GSTM1 *0 ⁄ *0 or GSTT1 *0 ⁄ *0 or both null genotypes, do not appear to be associated with ATD-induced hepatotoxicity in our Indian population.

Glutathione S-transferase M1 (GSTM1) polymorphism is associated with atopic dermatitis susceptibility in a Korean population

Atopic dermatitis (AD) is a chronic pruritic skin condition affecting as much as 15% of children in industrialized countries. While the underlying pathophysiology of AD is not entirely understood, several studies have suggested that AD may mediated by oxidative stress. Glutathione S-transferases (GSTs) are a class of polymorphic enzymes that function to protect against oxidative stress. To identify any possible associations between GSTs polymorphisms and AD susceptibility, the prevalence of two specific polymorphisms -GSTM1 and GSTT1 (homozygous deletion vs. undeleted) - were quantified by multiplex PCR in 145 patients with AD and 267 healthy controls. In individuals with AD, GSTM1/GSTT1 polymorphisms were compared with family history of AD, age of disease onset, disease severity [per SCORing Atopic Dermatitis (SCORAD)], serum IgE level and presence of other allergic diseases. While the GSTM1-null genotype was found to be significantly associated with AD (P = 0.033, OR = 1.579, 95% CI = 1.037-2.403), the correlation between the GSTT1-null genotype and AD did not reach statistical significance (P = 0.577, OR = 1.125, 95% CI = 0.744-1.702). The GSTM1-null genotype was also found to be significantly associated with a childhood onset of AD, the absence of other allergic diseases, and a family history of AD. In combination, these results suggest that GSTM1 is associated with AD susceptibility in Korean subjects.

Paracetamol metabolism and related genetic differences

Paracetamol (acetaminophen) is a worldwide used analgesic and antipyretic drug. It is metabolised via several metabolic pathways, including glucuronidation, sulfation, oxidation, hydroxylation, and deacetylation: Hepatic and other organ damage may occur, especially in overdose, because of the accumulation of a toxic metabolite. Intersubject and ethnic differences have been reported in paracetamol metabolism activation, suggesting possible differences in susceptibility to toxicity and in pain alleviation, linked to different pharmacogenetic profiles. This article aims at reviewing, in the literature, the links between paracetamol metabolism and enzyme genotypes in the context of toxic side effects and efficacy of paracetamol in therapeutics.

Germline polymorphisms of glutathione-S-transferase GSTM1, GSTT1 and p53 codon 72 in cervical carcinogenesis

The clinical significance of glutathione-S-transferase GSTM1, GSTT1 and p53 codon 72 polymorphisms in cervical carcinogenesis was investigated. Germline polymorphisms of GSTM1, GSTT1 and p53 codon 72 together with human papillomavirus (HPV) types were examined in a total of 457 blood and cervical smear samples from normal healthy women and the patients with premalignant and malignant cervical lesions. The 167 patients with low-grade squamous intraepithelial lesion (LSIL), 49 with high-grade SIL (HSIL) and 83 with squamous cell carcinoma (SCC) had significantly higher frequency of high-risk HPV than 158 controls. The 49 patients with HSIL and 83 with SCC had statistically higher frequency of null GSTT1 genotype than 158 controls. There was an increased odds ratio for null GSTT1 genotype in HSIL and SCC cases compared with controls among 191 patients with high-risk HPV. The 67 cases with HPV types 16 and/or 18 had higher frequency of the GSTT1 null genotype than 186 with other types of HPV. There was no statistical difference in the polymorphic frequency of GSTM1 and p53 codon 72 genotypes between SILs and controls with or without high-risk HPV. These results suggest that GSTT1 null genotype may increase the risk of cervical cancer particularly in the cases with high-risk HPV types in a Japanese population.

Association of glutathione S-transferase, EPHX, and p53 codon 72 gene polymorphisms with adult acute myeloid leukemia

Polymorphisms in genes encoding detoxification enzymes have been suggested as susceptibility factors for many solid tumors. However, their association with hematological malignancies is controversial. A case-control study was done to determine the association between glutathione S-transferase M1 (GSTM1), GSTT1, GSTP1, EPHX1, and p53 codon 72 polymorphisms as risk factors in 120 adult acute myeloid leukemia (AML) cases and 202 healthy controls by polymerase chain reaction-restriction fragment length polymorphism techniques. Data were analyzed using χ(2) and conditional logistic regression model. None of the polymorphisms studied alone was associated with increased risk for AML. However, the frequency of GSTT1 null genotype was higher among controls (28.7%) than AML cases (21.6%), which showed a protective effect of the null genotype (odds ratio = 0.58, 95% confidence interval: 0.33-1.05, p = 0.07). In a combined analysis, both EPHX1 (His113His) and GSTP1 (Ile/Val) genes imparted a fourfold risk for adult AML but did not reach statistical significance (odds ratio = 4.22, 95% confidence interval: 0.992-17.99, p = 0.05). These findings suggest that the etiology of adult AML cannot be explained by polymorphism at a single locus, perhaps because of complexity involved in the metabolism of diverse xenobiotic compounds, and therefore, multiple gene-gene interactions should be investigated to predict the risk of AML.

Distribution of glutathione S-transferase T1 and M1 genes polymorphisms in North East Indians: a potential report

BACKGROUND

Detoxifying glutathione S-transferase (GST) gene polymorphisms show variation in different ethnic populations. GST detoxifies and metabolizes carcinogens, including oxygen free radicals. GST polymorphisms have been associated with susceptibility to different diseases. In the current study, allelic polymorphisms of GSTM1 and GSTT1 were analyzed in three ethnic groups of North East (NE) India where a high prevalence of various cancers and other diseases such as hypertension, tuberculosis, and asthma have been reported.

METHODS

We compared the prevalence of GSTT1 and GSTM1 deletion genotypes, which were determined by multiplex polymerase chain reaction, in 422 voluntary, healthy NE Indians with those of other populations. The data was statistically analyzed.

RESULTS

The GSTT1-null genotype was found in 51%, 34.3%, and 15.7% of individuals (from Mizoram, Sikkim, and Assam regions of NE India, respectively), whereas the GSTM1-null genotype was found in 46.9%, 46%, and 35% of individuals from the same areas.

CONCLUSIONS

The NE Indians differ from the rest of the Indian population with reference to genotypic distribution of GST polymorphisms but the frequency was found to be similar to that which has been reported from China. This may explain the hypothesis of the common ancestral origin of both the NE Indians and the Chinese and a higher frequency of cancers such as gastric, esophageal, and oral cancers, which has been reported from these regions. This study establishes baseline frequency data for GST polymorphisms for future case control studies on the role these polymorphisms play with regard to diseases. The results presented here provide the first report on GST polymorphisms in the NE Indian population.

Polymorphisms of glutathione-S-transferase M1 and T1 and prostate cancer risk in a Tunisian population

Several genes involved in the metabolism of carcinogenesis have been found to be polymorphic in the human population, and specific alleles are associated with increase risk of cancer of various sites. This study is focused on the polymorphic enzymes glutathione-S-transferase M1 (GSTM1) and T1 (GSTT1) that involved in the detoxification of many xenobiotics involved in the etiology of prostate cancer.

OBJECTIVE

To evaluate whether GSTM1 and/or GSTT1 contribute to prostate cancer (CaP) etiology, we studied 110 incident CaP cases and 122 controls.

RESULTS

The probability of having CaP was increased in men who had homozygous deleted (non-functional) genotypes at GSTT1 (OR=2.17; 95% CI=1-3.79) but not GSTM1 (OR=0.89; 95% CI=0.66-1.88). Hence, individuals lacking the GSTT1 gene are at approximately twofold higher risk of developing prostate cancer in comparison with individuals with at least one active allele in the GSTT1 locus.

CONCLUSION

These results suggest that GSTT1 is associated with CaP risk. The effect of smoking associated with the GSTT10/0 genotype was not found to affect the risk of prostate cancer.

The 341C/T polymorphism in the GSTP1 gene is associated with increased risk of oesophageal cancer

Background

The Glutathione S-transferases (GSTs) comprise a group of enzymes that are critical in the detoxification of carcinogens. In this study the effects of polymorphisms in these genes on the risk of developing oesophageal squamous cell carcinoma (OSCC) were evaluated in a hospital-based case-control study in two South African population groups. Genetic polymorphisms in GSTs were investigated in 245 patients and 288 controls samples by PCR-RFLP analysis.

Results

The GSTP1 341T variant was associated with significantly increased risk of developing OSCC as observed from the odds ratios for the GSTP1 341C/T and GSTP1 341T/T genotypes (OR = 4.98; 95%CI 3.05-8.11 and OR = 10.9; 95%CI 2.43-49.1, respectively) when compared to the homozygous GSTP1 341C/C genotype. The risk for OSCC in the combined GSTP1 341C/T and T/T genotypes was higher in tobacco smokers (OR = 7.51, 95% CI 3.82-14.7), alcohol consumers (OR = 15.3, 95% CI 1.81-12.9) and those using wood or charcoal for cooking and heating (OR = 12.1, 95% CI 3.26-49) when compared to those who did not smoke tobacco, or did not consume alcohol or user other forms of fuel for cooking and heating. Despite the close proximity of the two GSTP1 SNPs (313A>G and 341C>T), they were not in linkage disequilibrium in these two population groups (D':1.0, LOD: 0.52, r²: 0.225). The GSTP1 313A/G polymorphism on the other hand, did not display any association with OSSC. The homozygous GSTT1*0 genotype was associated with increased risk of OSCC (OR = 1.71, 95%CI 1.18-2.46) while the homozygous GSTM1*0 genotype was associated with significantly decreased risk of OSCC in the Mixed Ancestry subjects (OR= 0.39, 95%CI 0.25-0.62).

Conclusions

This study shows that the risk of developing OSCC in the South African population can be partly explained by genetic polymorphisms in GST coding genes and their interaction with environmental factors such as tobacco smoke and alcohol consumption.

Evaluation of gene polymorphisms in exercise-induced oxidative stress and damage

Many potentially significant genetic variants related to oxidative stress have been identified and performance in endurance sports is a multi-factorial phenotype. Thus, it was decided to investigate the influences of the haptoglobin (Hp), MnSOD (Val9Ala), CAT (21A/T), GPX1 (Pro198Leu), ACE, glutathione S-transferases M1 (GSTM1) and T1 (GSTT1) genes' polymorphisms on the oxidative stress and damage suffered by human athletes (runners). Blood samples taken immediately after a race were submitted to genotyping, comet and TBARS assays, biochemical analyses of creatine kinase (CK), aspartate aminotransferase (AST) and alanine aminotransferase (ALT). MnSOD significantly influenced results of CK and a possible association between Hp1F-1S and Hp1S-2 genotypes with a superior TBARS values was found. Higher or lower TBARS and CK values or DNA damage also depended on the interaction between Hp and ACE or GST genotypes, indicating that MnSOD and Hp polymorphisms can be determining factors in performance, at least for runners.

Gene polymorphisms against DNA damage induced by hydrogen peroxide in leukocytes of healthy humans through comet assay: a quasi-experimental study

BACKGROUND

Normal cellular metabolism is well established as the source of endogenous reactive oxygen species which account for the background levels of oxidative DNA damage detected in normal tissue. Hydrogen peroxide imposes an oxidative stress condition on cells that can result in DNA damage, leading to mutagenesis and cell death. Several potentially significant genetic variants related to oxidative stress have already been identified, and angiotensin I-converting enzyme (ACE) inhibitors have been reported as possible antioxidant agents that can reduce vascular oxidative stress in cardiovascular events.

METHODS

We investigate the influences of haptoglobin, manganese superoxide dismutase (MnSOD Val9Ala), catalase (CAT -21A/T), glutathione peroxidase 1 (GPx-1 Pro198Leu), ACE (I/D) and gluthatione S-transferases GSTM1 and GSTT1 gene polymorphisms against DNA damage and oxidative stress. These were induced by exposing leukocytes from peripheral blood of healthy humans (N = 135) to hydrogen peroxide (H2O2), and the effects were tested by comet assay. Blood samples were submitted to genotyping and comet assay (before and after treatment with H2O2 at 250 microM and 1 mM).

RESULTS

After treatment with H2O2 at 250 microM, the GPx-1 polymorphism significantly influenced results of comet assay and a possible association of the Pro/Leu genotype with higher DNA damage was found. The highest or lowest DNA damage also depended on interaction between GPX-1/ACE and Hp/GSTM1T1 polymorphisms when hydrogen peroxide treatment increased oxidative stress.

CONCLUSIONS

The GPx-1 polymorphism and the interactions between GPX-1/ACE and Hp/GSTM1T1 can be determining factors for DNA oxidation provoked by hydrogen peroxide, and thus for higher susceptibility to or protection against oxidative stress suffered by healthy individuals.

Tumor response is predicted by patient genetic profile in rectal cancer patients treated with neo-adjuvant chemo-radiotherapy

The aim of the study was the identification of a pharmacogenetic profile predictive of the tumor regression grade (TRG), considered as tumor response parameter, after neo-adjuvant treatment in rectal cancer patients. A total of 238 rectal cancer patients treated in a neo-adjuvant setting by a fluoropyrimidines-based chemo-radiotherapy (RT) were genotyped for 25 genetic polymorphisms in 16 genes relevant for treatment-associated pathways. Two polymorphisms were associated with TRG in a multivariate analysis: hOGG1-1245C > G, which can affect radiosensitivity and MTHFR-677C > T, which is involved in fluoropyrimidines action. Patients bearing at least one variant allele had a lower chance to get TRG ≤ 2 (OR = 0.46 95% CI 0.23-0.90, P = 0.024; and OR = 0.48 95% CI 0.24-0.96, P = 0.034; respectively). An association trend was observed for ABCB1-3435C > T, which is responsible for the multi-drug resistance (odds ratio (OR) = 1.96, 95% confidence interval (CI) 0.98-3.95, P = 0.057). Exploratory classification and regression tree (CART) analysis highlighted high-order gene-gene and gene-environment interactions and a genetic signature associated with differential response, with hOGG1-1245C > G as the most predictive factor. Other significant variables were: ABCB1-3435C > T, MTHFR-677C > T, ERCC1-8092C > A, ABCC2-1249G > A, XRCC1-28152G > A, XRCC3-4541A > G and patients gender. On the basis of CART results, patients were categorized into three groups according to tumor response probability: intermediate and high profiles had a higher probability to get TRG ≤ 2 as compared with low profiles (OR = 4.12 95% CI 1.46-11.65, P < 0.001 and OR = 12.44, 95% CI 5.52-28.04, P < 0.0001, respectively). This study evidences a major role of hOGG1-1245C > G and MTHFR-677C > T polymorphisms in the tumor response of rectal cancer patients treated with chemo-RT in neo-adjuvant setting, and shows the relevance of gene-gene and gene-environment interactions for complex phenotypes as tumor response.

Influence of the polymorphism in candidate genes on late cardiac damage in patients treated due to acute leukemia in childhood

Anthracyclines have contributed significantly to the increased cure rate in pediatric oncology. Cardiac toxicity is an important late effect after anthracycline treatment and is thought to occur by reactive oxygen species mediated cardiac damage. We hypothesized that deactivating variants of superoxide dismutase II (SOD2) [rs4880 (-9Val > Ala)], catalase (CAT) [rs1001179 (-262C > T) and rs10836235 (c.66 + 78C > T)], GSTT1, and GSTM1 may increase the risk of developing cardiac toxicity, in patients exposed to anthracyclines. The hypothesis was tested in a cohort of 76 long-term survivals of acute lymphoblastic leukemia in childhood. Cardiac damage was evaluated as an attributive variable and compared to gene polymorphisms. In our study group, we show statistically significant correlation between CC homozygosity for CAT (rs10836235 (c.66 + 78C > T)) and cardiac damage after anthracycline exposure (p = 0.020). We found no statistically significant correlation between cardiac damage after anthracycline exposure and deactivating variants of SOD2 [rs4880 (-9Val > Ala)], CAT [rs1001179 (-262C > T), GSTT1, and GSTM1.

Glutathione S-transferase M1 inhibits dexamethasone-induced apoptosis in association with the suppression of Bim through dual mechanisms in a lymphoblastic leukemia cell line

Glutathione S-transferase mu (GSTM1) is mainly known as a detoxification enzyme but it has also been shown to be a negative regulator of apoptosis-related signaling cascades. Recently GSTM1 has been reported to be a significant risk factor for hematological relapse in childhood acute lymphoblastic leukemia, although the underlying mechanism remains largely unknown. Glucocorticoids play a crucial role in the treatment of childhood acute lymphoblastic leukemia, therefore we hypothesized that GSTM1 plays important roles in glucocorticoid-induced apoptotic pathways. To clarify the relationship between GSTM1 and drug resistance, GSTM1 was transfected into a T-acute lymphoblastic leukemia cell line, CCRF-CEM (CEM), and we established the GSTM1-expressing cell lines CEM/M1-4 and CEM/M1-9. Transduction of GSTM1 into CEM selectively decreased cellular sensitivity to dexamethasone in a manner that was independent of glutathione conjugation, but was due to apoptosis inhibition. Dexamethasone-induced p38-MAPK and Bim activation were concomitantly suppressed. Interestingly, nuclear factor kappa b (NF-kappaB) p50 activity was upregulated in GSTM1-expressing CEM. Inhibition of NF-kappaB by the pharmacological agent BAY11-7082 greatly enhanced the sensitivity of the GSTM1-expressing CEM to dexamethasone and was accompanied by an increase in Bim expression. Thus, we propose that GSTM1, a novel regulator of dexamethasone-induced apoptosis, causes dexamethasone resistance by suppression of Bim through dual mechanisms of both downregulation of p38-MAPK and upregulation of NF-kappaB p50.

Modulation of aflatoxin B1-mediated genotoxicity in primary cultures of human hepatocytes by diindolylmethane, curcumin, and xanthohumols

This study employed cultured human primary hepatocytes to investigate the ability of the putative chemopreventive phytochemicals curcumin (CUR), 3,3'-diindolylmethane (DIM), isoxanthohumol (IXN), or 8-prenylnaringenin (8PN) to reduce DNA adduct formation of the hepatocarcinogen aflatoxin B1 (AFB). Following 48 h of pretreatment, DIM and 8PN significantly increased AFB-DNA adduct levels, whereas CUR and IXN had no effect. DIM greatly enhanced the transcriptional expression of cytochrome P450 (CYP) 1A1 and CYP1A2 mRNA. Glutathione S-transferase mRNAs were not increased by any of the treatments. In vitro enzyme activity assays demonstrated that 8PN and DIM, but not CUR or IXN, inhibited human CYP1A1, CYP1A2, and CYP3A4 activities. To distinguish between treatment effects on transcription versus direct effects on enzyme activity for DIM, we evaluated the effects of pretreatment alone (transcriptional activation) versus cotreatment alone (enzyme inhibition). The results demonstrated that effects on gene expression, but not catalytic activity, are responsible for the observed effects of DIM on AFB-DNA adduct formation. The increase in AFB-DNA damage following DIM treatment may be explained through its substantial induction of CYP1A2 and/or its downregulation of GSTM1, both of which were significant. The increase in DNA damage by DIM raises potential safety risks for dietary supplements of DIM and its precursor indole-3-carbinol.