• 대한두경부종양학회지
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• 제19권2호
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• pp.148-157
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• 2003

Background and Objectives: Individual genetic susceptibilities to chemical carcinogens have been recognized as a major important host factors in human cancers. The cytochrome P450 family (CYPs) and glutathione S-transferase(GST) have been reported to be associated with risks to the smoking-related human cancers. Inactivation of tumor suppressor genes like p53 playa key role in tumor progression. The purpose of this study is to demonstrate an association between p53 overexpression and the prevalence of the genetic polymorphisms of CYP1A1 and GSTs in Korean head and neck squamous cell carcinoma (HNSCC). Materials and Methods: The polymorphisms of CYPIA1 and GSTs were analyzed by PCR and PCR-RFLP in 98 Korean head and neck squamous cell carcinoma patients. The expression of p53 was analyzed by immunohistochemistry with anti-p53 Ab (DO7). Results: Overexpression of p53 detected in 45.9% of HNSCC. The odds ratio for p53 overexpression in GSTM1(-), GSTT1(-), GSTP1(val/val) and CYP1A1(val/val) were 1.53, 1.83, 1.17 and 1.47, respectively. Among the combined genotypes, the odds ratio of the CYP1A1 val/val, GSTM1 (-), CYP1A1 val/val, GSTT1(-), and CYP1A1 val/val, GSTT1(-) were 2.0, 2.34 and 4.68, respectively. Conclusion: Based on our results, it might be suggested that p53 overexpression is slightly increased in GSTM1(-), GSTT1(-), GSTP1 val/val, CYP1A1 val/val genotypes. The further study is needed to evaluate the relationship and mechanism between the p53 overexpression and the specific CYP1A1 and GSTs genotypes.

• BMB Reports
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• 제34권1호
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• pp.66-72
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• 2001

To investigate the mechanism of adriamycin (ADM) resistance in the ADM resistant subline PC-14/ADM, we examined the expressions of p-glycoprotein (P-gp), topoisomerase I (Topo I) and II (Topo II), glutathione-S-transferases (GSTs), tissue transglutaminase (t-TG), epidermal growth factor receptor (EGFR), and E-cadherin and the activity of superoxide dismutase (SOD) in PC-14 and PC-14/ADM cells. There was no change in the cellular levels of P-gp, Topo I, Topo II, and the two isoforms of GSTs. However, SOD activity in PC-14/ADM cells was 2.38 fold higher than that in PC-14 cells. A marked induction of the t-TG expression was also observed in PC-14/ADM cells. In addition to those changes, expressions of EGFR and E-cadherin were down regulated in PC-14/ADM cells. Therefore, molecular modifications such as an increase in SOD activity, induction of the t-TG expression, and down regulation of EGFR and E-cadherin expressions may play important roles in PC-14/ADM cells during the development of ADM resistance.

• Toxicological Research
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• 제23권2호
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• pp.127-133
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• 2007

Metformin is a drug used to lower blood sugar levels in patients with type 2 diabetes via activation of adenosine monophosphate (AMP)-activated protein kinase (AMPK). The primary objective of this study was to investigate whether metformin at the pharmacologically effective concentrations affects the expressions of ${\gamma}$-glutamylcysteine synthetase and phase II antioxidant genes in the H4IIE cell. Treatment of the cells with either metformin or 5-aminoimidazole-4-carboxamide riboside (AICAR) abrogated tert-butylhydroxyquinone (t-BHQ) induction of ${\gamma}$-glutamylcysteine synthetase, a rate limiting enzyme of GSH synthesis. The ability of t-BHQ to induce glutathione S-transferases (GSTs), a major class of phase II detoxifying enzymes that playa critical role in protecting cells from oxidative stress or electrophiles, was also inhibited by the agents. Transcriptional gene repression by metformin was verified by the GSTA2 promoter luciferase assay. Moreover, either metformin or AICAR treatment significantly decreased t-BHQ-dependent induction of other GSTs (i.e., $GST{\mu}$ and $GST{\pi}$ forms). Taken together, our data indicate that metformin treatment may result in the repression of ${\gamma}$-glutamylcysteine synthetase and glutathione S-transferase genes possibly via AMPK activation.

• Asian Pacific Journal of Cancer Prevention
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• 제14권1호
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• pp.87-89
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• 2013

Glutathione S-transferases (GSTs) constitute a multigene family of multifunctional phase II metabolic enzymes. GSTT1, an important member of this group has a wide range of substrates including carcinogens. Total homozygous deletion or null genotype resulting in total lack of enzyme activity exists in populations for this enzyme. Since the null genotype may contribute to lower detoxification of carcinogens, this genotype is expected to increase cancer risk. The frequency of the GSTT1 null genotype is known to vary significantly among populations. However, little is known about its distribution in the hilly Kumaun region of northern India. Therefore, in this study, we determined the prevalence of the GSTT1 null polymorphism in the Kumaun popilation by conducting duplex PCR in 365 voluntary healthy individuals. The GSTT1 null genotype was detected in 18.4% of the individuals. Since GSTs play significant role in xenobiotic metabolism, the present data on GSTT1 genotype distribution should contribute in understanding genetic association with cancer risk in this understudied population.

• Journal of Preventive Medicine and Public Health
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• 제39권2호
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• pp.135-140
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• 2006

Objectives : Polymorphisms of genes from glutathione Stransferases (GSTs) and N-acetyltransferase 2 (NAT2) have been associated with increased susceptibility to various cancers. Previous results showed that East Asians such as Koreans, Japanese and Chinese have a much higher frequency of the GSTM1 and GSTT1 null genotypes and NAT2 rapid acetylator type. Therefore, we investigated the association between the polymorphic types of GSTs (GSTM1, GSTT1, GSTP1) and NAT2 and the incidence of gastric cancer which is one of the most prevalent cancers among the East Asians. Methods : It was performed in a case-control study consisting of 238 healthy subjects and 108 cancer patients (54 distal and 54 proximal carcinomas). We also evaluated the association between GSTs and NAT2 and the risk factors for gastric cancer such as alcohol consumption, smoking, H. pylori infection, family history of gastric cancer, and tumor location. Results : In our study, the percentage of cases whose hometown was rural was higher than those of controls (odds ratio (OR) =2.88; 95% CI=1.72-4.76), and the frequency of the lower socio-economic status increased significantly in patients (OR=2.53; 95% CI=1.59-4.02). There was no significant difference in the GST polymorphic types between the cases and controls. However, NAT2 rapid or intermediate acetylator types were frequently detected in the cases with family history of gastric cancer (OR=1.92; 95% CI=1.79-26.0). Conclusions : These results suggest that the hometown and socio-economic status are important environmental factors for gastric carcinogenesis, and NAT2 polymorphic types could be associated with familial gastric carcinoma.

• Asian Pacific Journal of Cancer Prevention
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• 제13권11호
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• pp.5647-5652
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• 2012

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 GSTT1simultaneously. 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.

• Asian Pacific Journal of Cancer Prevention
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• 제13권1호
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• pp.157-163
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• 2012

Objective: Glutathione S-transferases (GSTs) are multifunctional enzymes that play a crucial role in the detoxification of both the endogenous products of oxidative stress and exogenous carcinogens. Recent studies investigating the association between genetic polymorphisms in GSTs and the risk of adult brain tumors have reported conflicting results. The rationale of this pooled analysis was to determine whether the presence of a GST variant increases adult glioma susceptibility by combining data from multiple studies. Methods: In our meta-analysis, 12 studies were identified by a search of the MEDLINE, HIGHWIRE, SCIENCEDIRECT and EMBASE databases. Of those 12, 11 evaluated GSTM1, nine evaluated GSTT1 and seven evaluated GSTP1 Ile105Val. Between-study heterogeneity was assessed using ${\chi}^2$-based Q statistic and the $I^2$ statistic. Crude odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were used to estimate the association between GSTM1, GSTT1 and GSTP1 polymorphisms and the risk of adult gliomas. Results: The quantitative synthesis showed no significant evidence to indicate an association exists between the presence of a GSTM1, GSTT1 or GSTP1 Ile105Val haplotype polymorphism and the risk of adult gliomas (OR, 1.008, 1.246, 1.061 respectively; 95% CI, 0.901-1.129, 0.963-1.611, 0.653-1.724 respectively). Conclusions: Overall, this study did not suggest any strong relationship between GST variants or related enzyme polymorphisms and an increased risk of adult gliomas. Some caveats include absence of specific raw information on ethnic groups or smoking history on glioma cases in published articles; therefore, well-designed studies with a clear stratified analysis on potential confounding factors are needed to confirm these results.

• Journal of Plant Biotechnology
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• 제35권4호
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• pp.265-274
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• 2008

Glutathione S-transferases (GSTs) are multifunctional proteins encoded by a large gene family divided into Phi, Tau, Theta, Zeta, Lambda and DHAR classes on the basis of sequence identity. The Phi(F) and Tau(U) classes are plant-specific and ubiquitous. Their roles have been defined as herbicide detoxification and responses to biotic and abiotic stresses. Fifty-two members of the GST super-family were identified in the Arabidopsis thaliana genome, 13 members of which belong to the Phi class of GSTs (AtGSTFs). Based on the sequence similarities of AtGSTFs, 11 BAC clones were identified from Brassica rapa. Seven unique sequences of ORFs designated the Phi class candidates of GST derived from B. rapa (BrGSTFs) were detected from these 11 BAC clones by blast search and sequence alignment. Some of BrGSTFs were present in the same BAC clones indicating that BrGSTFs could also be clustered as usual in plant. They were mapped on B. rapa linkage group 2, 3, 9 and 10 and their nucleotide and amino acid sequences were highly similar to those of AtGSTFs. In addition, in silico analysis of BrGSTFs using Korea Brassica Genome Project 24K oligochip and microarray database for cold, salt and drought stresses revealed 15 unigenes to be highly similar to AtGSTFs and six of these were identical to one of BrGSTFs identified in the BAC clones indicating their expression. The sequences of BrGSTFs and unigenes identified in this study will facilitate further studies to apply GST genes to medical and agriculture purposes.

• 한국환경성돌연변이발암원학회지
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• 제24권1호
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• pp.40-45
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• 2004

In order to understand the mechanism of the regulation of drug metabolizing enzyme gene expression, we have studied the induction of CYP1A1 and GSTα, μ, π enzymes in Japanese monkey and rhesus monkey after the treatment with 3-methylcholanthrene (3MC) and di-n- butyl phthalate (DBP) and bisphenol A (BPA). The levels of mRNA were measured_by RT-PCR in brain, intestine and liver. In the case of adult monkey, treatment with 3MC induced CYP1A1 mRNA in brain by 2-fold. The treatment with DBP induced CYP1A1 mRNA. Effects of 3MC and DBP on GST mRNA expression was not clear. But GSTμ was slightly inhibited by the treatment with 3MC and DBP. GSTα was not induced by the treatment with 3MC and DBP in brain. GSTπ was slightly induced by the treatment with 3MC and DBP in brain. In the case of fetus monkey, the basal levels of fetus CYP1A1 mRNA and GSTs mRNA were relatively low compared to adult monkey. As the age of monkey increased, the basal levels of CYP1A1 mRNA were also increased. 3MC induced the expression of CYP1A1 mRNA in liver, whereas it didn't significantly induce CYP1A1 mRNA in brain. The levels of GSTμ and GSTα were not changed by the treatment with 3MC and DBP. GSTπ was slightly induced by the treatment with 3MC and DBP.

• Asian Pacific Journal of Cancer Prevention
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• 제14권12호
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• pp.7187-7191
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• 2013

Most of the exogenous and endogenous chemical compounds are metabolized by enzymes of xenobiotic processing pathways, including the phase I cytochrome p450 species. Carcinogens and their metabolites are generally detoxified by phase II enzymes like glutathione-S-transferases (GST). The balance of enzymes determines whether metabolic activation of pro-carcinogens or inactivation of carcinogens occurs. Under certain conditions, deregulated expression of xenobiotic enzymes may also convert endogenous substrates to metabolites that can facilitate DNA adduct formation and ultimately lead to cancer development. In this study, we aimed to test the association between deregulation of metabolizing genes and brain tumorigenesis. The expression profile of metabolizing genes CYP1A1 and GSTP1 was therefore studied in a cohort of 36 brain tumor patients and controls using Western blotting. In a second part of the study we analyzed protein expression of GSTs in the same study cohort by ELISA. CYP1A1 expression was found to be significantly high (p<0.001) in brain tumor as compared to the normal tissues, with ~4 fold (OR=4, 95%CI=0.43-37) increase in some cases. In contrast, the expression of GSTP1 was found to be significantly low in brain tumor tissues as compared to the controls (p<0.02). This down regulation was significantly higher (OR=0.05, 95%CI=0.006-0.51; p<0.007) in certain grades of lesions. Furthermore, GSTs levels were significantly down-regulated (p<0.014) in brain tumor patients compared to controls. Statistically significant decrease in GST levels was observed in the more advanced lesions (III-IV, p<0.005) as compared to the early tissue grades (I-II). Thus, altered expression of these xenobiotic metabolizing genes may be involved in brain tumor development in Pakistani population. Investigation of expression of these genes may provide information not only for the prediction of individual cancer risk but also for the prevention of cancer.