Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.5.1.18 (glutathione S-transferase)
22,582 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The many physiological, biochemical, and structure differences between rodents and humans, especially with regard to gestation and fetal development, invite questions as to the utility of rodent models for the prediction of risk of perinatal carcinogenesis in humans and for extrapolation of mechanistic studies. Here, the relevance of basic generalities, derived from rodent perinatal studies, to human contexts is considered. The cross-species usefulness of these generalities was upheld by the example of carcinogen activation and detoxification as determining factors. These have been established in rodent studies and recently indicted in humans by investigations of genetic polymorphisms in cytochromes P450, N-acetyltransferase, myeloperoxidase, quinone reductase, and glutathione S-transferase. Also, published data have been analyzed comparatively for diethylstilbestrol and irradiation, the two known human transplacental carcinogenic agents. At similar doses to those experienced by humans, both diethylstilbestrol and X- and gamma-irradiation in rodents and dogs yielded increased tumors at rates similar to those for humans. In rodents, there was a clearly negative relationship between total diethylstilbestrol dose and tumors per dose unit, and a similar pattern was suggested for radiation. Diethylstilbestrol had transgenerational effects that did not diminish over three generations. Overall, this analysis of the published literature indicates that there are basic qualitative and quantitative similarities in the responsiveness of human and rodent fetuses to carcinogens, and that dose effects may be complex and in need of further investigation.
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PMID:Predictive values of traditional animal bioassay studies for human perinatal carcinogenesis risk determination. 1531 88

Exploring the associations between genetic polymorphisms of metabolic enzymes and susceptibility to polycyclic aromatic hydrocarbon (PAH)-induced chromosomal damage is of great significance for understanding PAH carcinogenesis. Cytochrome P450, glutathione S-transferase, microsomal epoxide hydrolase, NAD(P)H:quinone oxidoreductase, and N-acetyltransferase are PAH-metabolizing enzymes. In this study, we genotyped for the polymorphisms of these genes and assessed their effects on cytokinesis-block micronucleus (CBMN) frequencies in peripheral blood lymphocytes among 141 coke-oven workers and 66 non-coke-oven worker controls. The geometric means of urinary 1-hydroxypyrene levels in coke-oven workers and the controls were 12.0 and 0.7 micromol/mol creatinine, respectively (P < 0.01). The CBMN frequency (number of micronuclei per 1,000 binucleated lymphocytes) was significantly higher in coke-oven workers (9.5 +/- 6.6 per thousand) than in the controls (4.0 +/- 3.6 per thousand; P < 0.01). Among the coke-oven workers, age was positively associated with CBMN frequency; the mEH His113 variant genotype exhibited significantly lower CBMN frequency (8.5 +/- 6.5 per thousand) than did the Tyr113/Tyr113 genotype (11.3 +/- 6.4 per thousand; P < 0.01); the low mEH activity phenotype exhibited a lower CBMN frequency (8.6 +/- 6.8 per thousand) than did the high mEH activity phenotype (13.2 +/- 6.7 per thousand; P = 0.01); the GSTP1 Val105/Val105 genotype exhibited a higher CBMN frequency (15.0 +/- 5.8 per thousand) than did the GSTP1 Ile105/Ile105 or Ile105/Val105 genotypes (9.3 +/- 6.5 per thousand; P < 0.01); the joint effect of high mEH activity phenotype and GSTM1 null genotype on CBMN frequencies was also found. Gene-environment interactions between occupational PAH exposure and polymorphisms of mEH and/or GSTM1 were also evident. These results indicate that the mEH, GSTP1, and GSTM1 polymorphisms may play a role in sensitivity or genetic susceptibility to the genotoxic effects of PAH exposure in the coke-oven workers.
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PMID:Effects of genetic polymorphisms of metabolic enzymes on cytokinesis-block micronucleus in peripheral blood lymphocyte among coke-oven workers. 1546 80

Coffee drinking has been associated with reduced incidence of colorectal cancer, possibly via chemoprotection/modification of the metabolism of dietary heterocyclic amine carcinogens such as 2-amino-1-methyl-6-phenylimidazo-[4,5-b]pyridine (PhIP) by kahweol and cafestol palmitates (K/C), two components of unfiltered coffee. Using the PhIP-exposed male Fisher F344 rat as a model, K/C have been shown to reduce colonic PhIP-DNA adducts by > 50%. We have used the male F344 rat to investigate the effects of dietary K/C (0.02-0.2% as a 1:1 mixture) on the metabolism of PhIP by N-acetyltransferase- (NAT), sulfotransferase- (SULT), and glutathione-dependent pathways. K/C decreased hepatic NAT-dependent PhIP activation by up to 80% in a dose-dependent manner. Conversely, hepatic glutathione S-transferase (GST) activity/expression increased, e.g., 3-4 fold toward 1-chloro-2,4-dinitrobenzene (total activity), up to 23-fold toward 4-vinylpyridine (rGSTP1), and approximately 7-fold for rGSTA2 protein. These effects had fully developed after 5 days of the test diet and persisted for at least 5 days after withdrawal of K/C. Hepatic glutathione increased two- to threefold and this increase was more short-lived than other changes. K/C did not modify hepatic SULT activity or colon NAT and GST activities. Benzylisothiocyanate and black tea, which have also been shown to reduce the formation of PhIP-DNA adducts in this model, had little effect on hepatic NAT, SULT, GST, or GSH. In primary culture of rat hepatocytes, both kahweol and cafestol palmitates reduced NAT activity by 80%. In summary, the unique potential of K/C to convert rapid acetylators to a slow acetylator phenotype, accompanied by GST induction, might contribute to chemoprevention against cancers associated with heterocyclic amines.
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PMID:Potential chemoprotective effects of the coffee components kahweol and cafestol palmitates via modification of hepatic N-acetyltransferase and glutathione S-transferase activities. 1546 54

Several chemicals have been associated with risk of non-Hodgkin's lymphoma (NHL), many of which are substrates for N-acetyltransferase (NAT) and glutathione S-transferase (GST) enzymes. We investigated the association between polymorphisms in genes coding for these enzymes and NHL risk in a population-based study (389 cases and 535 controls). NAT1 slow genotype was associated with a slightly increased risk in women [odds ratios (OR) = 1.4; 95% confidence interval (CI) = 0.9-2.3], but not in men. NAT2 slow genotype was not associated with risk in either sex. The two slow genotypes of NAT1 and NAT2 combined were associated with a minor increase of risk in women (OR = 1.4; 0.8-2.4). There was no association with the GSTM1 or GSTT1 null genotype in either sex, irrespective of histological subtypes. Individuals with GSTP1 Val homozygotes had non-significant excessive risk of marginal zone lymphoma (OR = 1.8; 0.6-5.1) and 'other' B-cell NHLs (OR = 1.6; 0.7-3.6), but lower risk of diffuse large B-cell lymphoma (OR = 0.2; 0.1-0.96). Risk did not elevate with an increasing number of high-risk GST alleles in either sex. In summary, although NAT1, NAT2, GSTM1, GSTT1, or GSTP1 polymorphisms do not appear to be associated with NHL risk overall, there might be gender-specific and subtype-specific associations that require confirmation.
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PMID:Association of NAT and GST polymorphisms with non-Hodgkin's lymphoma: a population-based case-control study. 1572 81

We clarified that major human cytochrome P450 (P450) enzymes were expressed in a chimeric mouse line established recently in Japan, in which the liver could be replaced by more than 80% with human hepatocytes. In this study, we investigated major human phase II enzymes such as UDP-glucuronosyltransferase (UGT), sulfotransferase (SULT), N-acetyltransferase (NAT), and glutathione S-transferase (GST) in the livers of chimeric mice by mRNA, protein, and enzyme activity using reverse transcription-polymerase chain reaction, Western blot analysis, and high-performance liquid chromatography, respectively. Human UGT, SULT, NAT, and GST mRNA were expressed in the liver of the chimeric mice, and UGT2B7, SULT1E1, SULT2A1, and GSTA1 proteins could be detected. The expression of mRNA and protein was correlated with the human albumin (hAlb) concentration in mouse blood, the replacement of which by human hepatocytes could be estimated by the hAlb concentration in the blood of the chimeric mice, because the chimeric mice produce human albumin. The enzyme activities, such as morphine 6-glucuronosyltransferase activity and estrone 3-sulfotransferase activity, activities that are specific to humans but not to mice, were increased in a hAlb concentration-dependent manner. The chimeric mice with humanized liver with nearly 90% replacement by human hepatocytes demonstrated almost the same protein contents of human phase II enzymes and enzyme activities as those of the donor. In conclusion, the chimeric mice exhibited an efficient capacity of drug conjugation similar to that in humans. These chimeric mice expressed human phase II enzymes as well as P450s, suggesting that they could be a useful animal model in drug development.
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PMID:Expression of human phase II enzymes in chimeric mice with humanized liver. 1593 51

We completed a phase I trial of indole-3-carbinol (I3C) in 17 women (1 postmenopausal and 16 premenopausal) from a high-risk breast cancer cohort. After a 4-week placebo run-in period, subjects ingested 400 mg I3C daily for 4 weeks followed by a 4-week period of 800 mg I3C daily. These chronic doses were tolerated well by all subjects. Hormonal variables were measured near the end of the placebo and dosing periods, including determination of the urinary 2-hydroxyestrone/16alpha-hydroxyestrone ratio. Measurements were made during the follicular phase for premenopausal women. Serum estradiol, progesterone, luteinizing hormone, follicle-stimulating hormone, and sex hormone binding globulin showed no significant changes in response to I3C. Caffeine was used to probe for cytochrome P450 1A2 (CYP1A2), N-acetyltransferase-2 (NAT-2), and xanthine oxidase. Comparing the results from the placebo and the 800 mg daily dose period, CYP1A2 was elevated by I3C in 94% of the subjects, with a mean increase of 4.1-fold. In subjects with high NAT-2 activities, these were decreased to 11% by I3C administration but not altered if NAT-2 activity was initially low. Xanthine oxidase was not affected. Lymphocyte glutathione S-transferase activity was increased by 69% in response to I3C. The apparent induction of CYP1A2 was mirrored by a 66% increase in the urinary 2-hydroxyestrone/16alpha-hydroxyestrone ratio in response to I3C. The maximal increase was observed with the 400 mg daily dose of I3C, with no further increase found at 800 mg daily. If the ratio of hydroxylated estrone metabolites is a biomarker for chemoprevention, as suggested, then 400 mg I3C daily will elicit a maximal protective effect.
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PMID:A phase I study of indole-3-carbinol in women: tolerability and effects. 1610 43

Associations between genotypes of phase 2 enzymes and cancer risk are extracted from epidemiological studies, namely case-control studies. Variant alleles in glutathione S-transferase (GST), UDP-glucuronosyltransferase (UGT), sulfotransferase (SULT), and N-acetyltransferase (NAT) have been used as molecular genetic biomarkers of risk. GSTM(my)1 has been associated with an increased risk of colorectal cancer, lung cancer, and bladder cancer and GSTP(pi)1 with prostate cancer. UGT1A1*28 and *37 are both associated with an increased risk of breast cancer as is SULT1A1*2. The presence of UGT1A1*28 results in an increased risk of ovarian cancer and NAT2 of colorectal and lung cancer. A high frequency of SULT1A1*1 has been identified in patients with breast cancer; the role in colorectal cancer is more controversial. This chapter discusses the balance between carcinogen activation and detoxification in relation to phase 2 enzymes.
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PMID:Cancer and molecular biomarkers of phase 2. 1639 74

There is wide variability in the response of individuals to standard doses of drug therapy. This is an important problem in clinical practice, where it can lead to therapeutic failures or adverse drug reactions. Polymorphisms in genes coding for metabolising enzymes and drug transporters can affect drug efficacy and toxicity. Pharmacogenetics aims to identify individuals predisposed to a high risk of toxicity and low response from standard doses of anti-cancer drugs. This review focuses on the clinical significance of polymorphisms in drug-metabolising enzymes (cytochrome P450 [CYP] 2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4, CYP3A5, dihydropyrimidine dehydrogenase, uridine diphosphate glucuronosyltransferase [UGT] 1A1, glutathione S-transferase, sulfotransferase [SULT] 1A1, N-acetyltransferase [NAT], thiopurine methyltransferase [TPMT]) and drug transporters (P-glycoprotein [multidrug resistance 1], multidrug resistance protein 2 [MRP2], breast cancer resistance protein [BCRP]) in influencing efficacy and toxicity of chemotherapy. The most important example to demonstrate the influence of pharmacogenetics on anti-cancer therapy is TPMT. A decreased activity of TPMT, caused by genetic polymorphisms in the TPMT gene, causes severe toxicity with mercaptopurine. Dosage reduction is necessary for patients with heterozygous or homozygous mutation in this gene. Other polymorphisms showing the influence of pharmacogenetics in the chemotherapeutic treatment of cancer are discussed, such as UGT1A1*28. This polymorphism is associated with an increase in toxicity with irinotecan. Also, polymorphisms in the DPYD gene show a relation with fluorouracil-related toxicity; however, in most cases no clear association has been found for polymorphisms in drug-metabolising enzymes and drug transporters, and pharmacokinetics or pharmacodynamics of anti-cancer drugs. The studies discussed evaluate different regimens and tumour types and show that polymorphisms can have different, sometimes even contradictory, pharmacokinetic and pharmacodynamic effects in different tumours in response to different drugs. The clinical application of pharmacogenetics in cancer treatment will therefore require more detailed information of the different polymorphisms in drug-metabolising enzymes and drug transporters. Larger studies, in different ethnic populations, and extended with haplotype and linkage disequilibrium analysis, will be necessary for each anti-cancer drug separately.
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PMID:Genetic polymorphisms of drug-metabolising enzymes and drug transporters in the chemotherapeutic treatment of cancer. 1650 59

Three first-line antituberculosis drugs, isoniazid, rifampicin and pyrazinamide, may induce liver injury, especially isoniazid. This antituberculosis drug-induced liver injury ranges from a mild to severe form, and the associated mortality cases are not rare. The major drug-metabolizing enzyme of isoniazid is N-acetyltransferase. Other possible enzymes are CYP2E1 and glutathione S-transferase. There is evidence that polymorphisms of the genes that encode these enzymes may influence the activity of the corresponding drug-metabolizing enzymes. Recent studies demonstrated that these genetic polymorphisms may be associated with the susceptibility to antituberculosis drug-induced liver injury. The proposed risk-associated genotypes are NAT2 slow acetylator (without wild-type NAT2*4 allele), CYP2E1 *1A/*1A (homozygous wild type) and homozygous null GSTM1 genotype. Although the available data in the field are still limited and warrants further confirmation in different ethnic populations with larger sample sizes, it still cast some light on the application of these pharmacogenetic or pharmacogenomic approaches to prevent grave antituberculosis drug-induced liver injury in the near future.
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PMID:Genetic polymorphisms of drug-metabolizing enzymes and the susceptibility to antituberculosis drug-induced liver injury. 1726 90

Genetically determined factors that alter the metabolism of tobacco carcinogens can influence an individual's susceptibility to bladder cancer. The associations between the genotypes of glutathione S-transferase (GST) M1, GSTP1, GSTT1 and N-acetyltransferase (NAT) 1 and the phenotypes of NAT2 and cytochrome P450 (CYP) 1A2 and bladder cancer risk were examined in a case-control study involving 731 bladder cancer patients and 740 control subjects in Los Angeles County, California. Individual null/low-activity genotypes of GSTM1, GSTT1 and GSTP1 were associated with a 19-48% increase in odds ratio (OR) of bladder cancer. The strongest association was noted for GSTM1 [OR for the null genotype = 1.48, 95% confidence interval (CI) = 1.19-1.83]. When the three GST genes were examined together, there was a monotonic, statistically significant association between increasing number of null/low-activity genotypes and risk (P for trend = 0.002). OR (95% CI) for one and two or more null/low-activity GST genotypes was 1.42 (1.12-1.81) and 1.71 (1.25-2.34), respectively, relative to the absence of null/low-activity GST genotype. NAT2 slow acetylation was associated with doubled risk of bladder cancer among individuals with known high exposures to carcinogenic arylamines (OR = 2.03, 95% CI = 1.12-3.69, P = 0.02). The effect of NAT2 slow acetylation was even stronger in the presence of two or more null/low-activity GST genotypes. There were no associations between bladder cancer risk and NAT1 genotype or CYP1A2 phenotype.
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PMID:Genetic determinants in the metabolism of bladder carcinogens in relation to risk of bladder cancer. 1854 63


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