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)

Enzymatic and non-enzymatic antioxidants serve as an important biological defense against environmental oxidative stress. Information on antioxidant defense in fish is meager despite that fish are constantly exposed to a myriad of environmental stress including the oxidants. This study, therefore, assesses the activities of antioxidant enzymes viz., glutathione peroxidase, catalase and glutathione S-transferase and the non-enzymatic antioxidants viz., glutathione and metallothionein in various tissues of freshwater fish Channa punctatus (Bloch), in response to short-term and long-term exposures to paper mill effluent. The fish were exposed to the effluent at a concentration of 1.0% (v/v) for 15, 30, 60 and 90 days. The exposure caused a time-dependent increase in glutathione level (P < 0.001), activities of glutathione peroxidase (P < 0.05 to P < 0.001), glutathione S-transferase (P < 0.001) and a marginal initial decrease in catalase activity in the liver (P < 0.01 to P < 0.001). Metallothionein was induced in liver after 60 days of exposure. Two isoforms of metallothionein were detected. Catalase activity also increased 60 days afterwards. Antioxidant pattern was different in gill and kidney showing that liver was more resistant to oxidative damage as compared to gills and kidney. Our results demonstrate a pollutant-induced adaptive response in fish. In addition, levels of enzymatic and non-enzymatic tissue antioxidants may serve as surrogate markers of exposure to oxidant pollutants in fish.
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PMID:Induction of hepatic antioxidants in freshwater catfish (Channa punctatus Bloch) is a biomarker of paper mill effluent exposure. 1109 56

Cox17 is the candidate copper metallochaperone for delivery of copper ions to the mitochondrion for assembly of cytochrome c oxidase. Cox17 purified as a recombinant molecule lacking any purification tag binds three Cu(I) ions per monomer in a polycopper cluster as shown by X-ray absorption spectroscopy. The CuCox17 complex exists in a dimer/tetramer equilibrium with a 20 microM k(d). The spectroscopic data do not discern whether the dimeric complex forms a single hexanuclear Cu(I) cluster or two separate trinuclear Cu(I) clusters. The Cu(I) cluster(s) exhibit(s) predominantly trigonal Cu(I) coordination. The cluster(s) in Cox17 resemble(s) the polycopper clusters in Ace1 and the Cup1 metallothionein in being pH-stable and luminescent. The physical properties of the CuCox17 complex purified as an untagged molecule differ from those reported previously for a GST-Cox17 fusion protein. The CuCox17 cluster is distinct from the polycopper cluster in Cup1 in being labile to ligand exchange. CuCox17 localized within the intermitochondrial membrane space appears to be predominantly tetrameric, whereas the cytosolic CuCox17 is primarily a dimeric species. Cys-->Ser substitutions at Cys23, Cys24, or Cys26 abolish the Cox17 function and prevent tetramerization, although Cu(I) binding is largely unaffected. Thus, the oligomeric state of Cox17 may be important to its physiological function.
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PMID:The mitochondrial copper metallochaperone Cox17 exists as an oligomeric, polycopper complex. 1117 Mar 91

The purpose of this study was to define the prognostic value of a group of molecular tumor markers in a well-staged population of patients treated with trimodality therapy for esophageal cancer. The original pretreatment paraffin-embedded endoscopic esophageal tumor biopsy material was obtained from 118 patients treated with concurrent cisplatin + 5-fluorouracil (5-FU) + 45 Gy radiation followed by resection from 1986 until 1997 at the Duke University Comprehensive Cancer Center. Three markers of possible platinum chemotherapy association [metallothionein (MT), glutathione S-transferase-pi (GST-pi), P-glycoprotein (P-gp or multidrug resistance)] and one marker of possible 5-FU association [thymidylate synthase (TS)] were measured using immunohistochemistry. The median cancer-free survival was 25.0 months, with a significantly improved survival for the 38 patients who had a complete response (P < 0.001). High-level expression of GST-pi, P-gp, and TS were associated with a decreased survival. MT was not significant in this population. Multivariate analysis identified high-level expression in two of the platinum markers (GST-pi and P-gp) and the 5-FU marker TS as independent predictors of early recurrence and death. In conclusion, this investigation measured three possible markers associated with platinum and one possible marker associated with 5-FU in a cohort of esophageal cancer patients. Independent prognostic significance was observed, which suggests that it may be possible to predict which patients may benefit most from trimodality therapy. These data need to be reproduced in a prospective investigation.
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PMID:The prognostic value of molecular marker analysis in patients treated with trimodality therapy for esophageal cancer. 1129 49

This work compares glutathione levels, glutathione S-transferase activities and isoenzyme expression, metallothionein levels and P-glycoprotein expression in normal ovaries, and in epithelial ovarian tumor biopsies from patients prior to chemotherapy or following relapse. These parameters have been implicated as determinants of response to cytotoxic chemotherapy. Large differences were found between normal ovary and ovarian tumors, but no significant differences were observed between tumors taken before or after cytotoxic chemotherapy. These data do not support a role for these biochemical parameters in the decreased response seen in patients with recurrent or progressive disease.
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PMID:Correlation of drug resistance-associated parameters in ovarian tumor biopsies. 1157 13

Epidemiological studies have shown that there exists some correlation between cadmium exposure and human cancers. The evidence that cadmium and cadmium compounds are probable human carcinogens is also supported by experimental studies reporting induction of malignant tumors formation in multiple species of laboratory animals exposed to these compounds. In vitro studies with mammalian cells have also shown that cadmium is clastogenic, but its mutagenic potential is rather weak. In this research, we performed the MTT assay for cell viability to assess the cytotoxicity of cadmium chloride (CdCl2), and the CAT-Tox (L) assay to measure the induction of stress genes in thirteen different recombinant cell lines generated from human liver carcinoma cells (HepG2), by creating stable transfectants of different mammalian promoter-chloramphenicol acetyltransferase (CAT) gene fusions. Cytotoxicity experiments with the parental cell line yielded a LC50 of 6.1 +/- 0.8 microg/mL, upon 48 h of exposure. Four (metallothionein--HMTIIA, 70-kDa heat shock protein--HSP70, xenobitic response element--XRE, and cyclic adenosine monophosphate response element--CRE) out of the 13 constructs evaluated showed statistically significant inductions (p < 0.05). The induction of these genes was concentration-dependent. Marginal inductions were also recorded for the c-fos, and 153-kDa growth arrest DNA damage (GADD153) promoters, indicating a potential for CdCl2 to damage DNA. However, no significant inductions (p > 0.05) of gene expression were recorded for cytochrome P4501A1--CYP1A1, glutathion-S-transferase Ya subunit--GST Ya, nuclear factor kappa (B site) response element--NFkappaBRE, tumor suppressor protein response element--p53RE, 45-kDa growth arrest DNA damage--GADD45, 78-kDa glucose regulated protein--GRP78, and retinoic acid response element--RARE. As expected, these results indicate that metallothioneins and heat shock proteins appear to be excellent candidates for biomarkers for detecting cadmium-induced proteotoxic effects at the molecular and cellular levels. Induction of XRE indicates the potential involvement of CdCl2 in the biotransformation process in the liver, while activation of CRE indicates stimulation of cellular signaling through the protein kinases pathway.
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PMID:Cytotoxicity and transcriptional activation of stress genes in human liver carcinoma cells (HepG2) exposed to cadmium chloride. 1167 4

Elemental mercury (Hg(0)) is a ubiquitous toxic pollutant. Exposure to Hg(0) vapor typically is by inhalation, and the kidney is the primary target organ. Glutathione (GSH) and metallothionein (MT) appear to mitigate mercury toxicity. However, little is known about GSH or MT regulation after Hg(0) vapor exposure, particularly during pregnancy, a time of high sensitivity to most metals. Thus, this study sought to determine renal mercury accumulation and MT- and GSH-related gene expression following Hg(0) vapor exposure in nonpregnant, pregnant, and neonatal rats exposed in utero. Groups (n = 5) of pregnant rats (Long-Evans) were exposed to Hg(0) vapor (4 mg/m(3)) or air (control) for 2 h/d from gestational day (GD) 6 to 15, and kidneys from dams and pups were removed at various times during and after the onset of exposure. For comparative purposes, nonpregnant female rats were exposed to Hg(0) for 10 d under the same conditions. Renal mercury, MT protein, and GST activity were assayed by standard analytical techniques. Western blot analysis was also performed using antibodies against MT and GST-pi. GSH-related gene expression was studied by cDNA microarray. Hg(0) vapor exposure produced renal accumulation of mercury in nonpregnant, pregnant, and neonatal rats. However, the transplacentally exposed neonates accumulated approximately 1000-fold less mercury than adults. Hg(0) vapor exposure produced a time-dependent increase in renal MT protein in nonpregnant and pregnant rats, but not in neonatal rats. Maximum MT increases were observed on d 10 (fivefold) in nonpregnant and GD 15 (threefold) in pregnant rats. Activation of the MT gene by Hg(0) was confirmed at the translational level by Western blot analysis and at the transcriptional level by Northern blot analysis. Microarray analysis revealed a significant upregulation in the renal expression of the GST-pi, GST-Ya, and microsomal GST and GST5-5 genes in nonpregnant and pregnant rats. Western blot and enzyme assay confirmed the upregulation of GST genes after Hg(0) exposure. Thus, in response to Hg(0) vapor exposure, the expression of the MT gene and various GST genes is activated in nonpregnant and pregnant rats. Activation of these genes could be part of a defensive response directed at decreasing renal mercury toxicity, and may help divert the metal away from the fetus.
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PMID:Effect of mercury vapor exposure on metallothionein and glutathione s-transferase gene expression in the kidney of nonpregnant, pregnant, and neonatal rats. 1216 10

In order to study whether the presence of mechanisms of drug resistance is a characteristic unique to advanced lung cancer or occurs already early in the course of the disease, we investigated the expression of gluathione S-transferase-pi (GST-pi), P-glycoprotein (P-gp) and metallothionein (MT) in 80 human lung carcinomas and in 20 normal lung tissues using immunohistochemistry. We found that all three proteins were expressed in resected normal lung and lung carcinomas. Expression of GST-pi and MT was elevated in tumor tissues in comparison to normal lung tissues, whereas P-gp was highly expressed in normal lung. GST-pi and MT expression increased with increasing tumor volume and differentiation grade. These results suggest that the level of GST-pi and MT in lung cells increases as cells progress from the normal to the transformed state and that drug resistance gene products are already present in lung carcinomas at the time of surgical resection.
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PMID:Expression of drug resistance gene products during progression of lung carcinomas. 1237 15

In recent years, there have been a number of efforts to identify genes that are expressed in mature ovarian follicles in response to an ovulatory dose of LH or its homologue hCG. This review keys on 20 ovulation-specific genes that we have identified by the molecular procedure known as differential display. The objective is to use this sampling of genes to illustrate the diversity in the temporal and spatial patterns of expression of genes in the ovary following the stimulus of this gonadal target tissue by a single glycoprotein hormone. The specific genes that are surveyed include 5-aminolevulinate synthase; early growth response protein-1; gamma-glutamylcysteine synthetase; cyclooxygenase-2; epiregulin; pituitary adenylate cyclase-activating polypeptide; tumor necrosis factor-stimulated gene-6; regulator of G-protein signaling protein-2; adrenodoxin; steroidogenic acute regulatory protein; 3alpha-hydroxysteroid dehydrogenase; CD63, a disintegrin and metalloproteinase with thrombospondin motifs; tissue inhibitor of metalloproteinase-1; carbonyl reductase, a G-protein-coupled receptor; pancreatitis-associated protein-III; glutathione S-transferase; and metallothionein-1. The ovulatory expression of these different genes is predominantly within the granulosa layer of mature follicles. However, there were also instances of expression in the thecal and stromal tissue of the ovary, as well as in vascular endothelial cells and in luteal tissue. The overwhelming impression is that the molecular events of ovulation are far more complex, and therefore more highly ordered, than originally imagined.
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PMID:Temporal and spatial patterns of ovarian gene transcription following an ovulatory dose of gonadotropin in the rat. 1244 39

Elemental mercury (Hg0) is a highly toxic chemical with increasing public health concern. Although the lung receives the highest exposure to Hg0 vapor, it is resistant to Hg0 toxicity relative to the kidney and brain. In an earlier study, exposure of rats to 4 mg Hg0 vapor/m3, 2 h per day for 10 days, did not produce pathological alterations in the lung but increased metallothionein and glutathione S-transferase in the kidney. This study was undertaken to examine pulmonary gene expression associated with Hg0 vapor inhalation. Total RNA was extracted from lung tissues of rats, previously exposed to air or Hg0 vapor, and subjected to microarray analysis. Hg0 vapor exposure increased the expression of genes encoding inflammatory responses, such as chemokines, tumor necrosis factor-alpha (TNFalpha), TNF-receptor-1, interleukin-2 (IL-2), IL-7, prostaglandin E2 receptor, and heat-shock proteins. As adaptive responses, glutathione S-transferases (GST-pi, mGST1), metallothionein, and thioredoxin peroxidase were all increased in response to Hg exposure. Some transporters, such as multidrug resistance-associated protein (MRP), P-glycoprotein, and zinc transporter ZnT1, were also increased in an attempt to reduce pulmonary Hg load. The expression of transcription factor c-jun/AP-1 and PI3-kinases was suppressed, while the expression of protein kinase-C was increased. Expression of epidermal fatty acid-binding protein was also enhanced. Real-time RT-PCR and Western blot analyses confirmed the microarray results. In summary, genomic analysis revealed an array of gene alterations in response to Hg0 vapor exposure, which could be important for the development of pulmonary adaptation to Hg during Hg0 vapor inhalation.
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PMID:Genomic analysis of the rat lung following elemental mercury vapor exposure. 1273 Jun 25

Antioxidant defenses consisting of catalase, superoxide dismutase (SOD), xanthine oxidase (XOD), glutathione peroxidase (GPX), and glutathione S-transferase were estimated in liver and kidney of freshwater fish subjected to a sublethal concentration of cadmium chloride (Cd2+), i.e., 5 ppm. The aim of the study was to evaluate the role of antioxidant defenses during cadmium-induced oxidative stress. Significant elevations in liver and kidney of all of the above detoxification enzymes were evident from the 7th day onward, were maintained until the 15th day, and then decreased slightly on the 30th day of exposure to cadmium stress. Between the two tissues studied, liver recorded higher activity for all enzymes except GPX, which was elevated significantly in kidney (82.85%). Both liver and kidney recorded more or less similar increases of SOD (86.61% and 86.32%, respectively), and XOD (86.41% and 84.19%, respectively). The findings indicate that tissue glutathione-dependent enzymes as well as other antioxidant enzymes function in protection against Cd2+ toxicity and that these antioxidants provide a first line of defense against Cd2+ before the induction of any metallothionein synthesis occurs.
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PMID:Cadmium-induced antioxidant defense mechanism in freshwater teleost Oreochromis mossambicus (Tilapia). 1292 52


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