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)

We examined the impact of purified bacterially synthesized GST-MDA-7 (IL-24) and ionizing radiation on the proliferation and survival of nonestablished human glioblastoma multiforme (GBM) cells. Glioma cell types expressing mutated PTEN and p53 molecules, activated ERBB1VIII, overexpressing wild type ERBB1 or without receptor overexpression were selected. In MTT assays, GST-MDA-7 caused a dose-dependent reduction in the proliferation of nonestablished glioma cells; however only at higher concentrations did GST-MDA-7 reduce cell viability. The anti-proliferative and cytotoxic effects of GST-MDA-7 were enhanced by radiation in a greater than additive fashion that correlated with JNK1/2/3 activation. The reduction in cell growth and enhancement in cell killing by the combination of GST-MDA-7 and radiation were blocked by an ROS scavenger, N-acetyl cysteine (NAC), a JNK1/2/3 inhibitor SP600125, a pan-caspase inhibitor (zVAD) and by an inhibitor of caspase 9 (LEHD), but not by an inhibitor of caspase 8 (IETD). Low concentrations of either GST-MDA-7 or radiation reduced clonogenic survival, however colony formation ability was significantly further decreased when the two treatments were combined, which was also blocked by inhibition of caspase 9 function. In general agreement with activation of the intrinsic caspase pathway, cell death correlated with reduced BCL-XL expression and with increased levels of the pro-apoptotic proteins BAD and BAX. Inhibition of caspase 9 after combination treatment blunted neither JNK1/2/3 activation nor the enhanced expression of BAD and BAX, but did block caspase 3 cleavage, reduced expression of BCL-XL and inhibition of ERK1/2 activity. In contrast, incubation with NAC blocked JNK1/2/3 activation and cell killing, but not the increases in BAD and BAX expression. These findings argue that after combination treatment JNK1/2/3 activation is a primary pro-apoptotic event and loss of BCL-XL expression and ERK1/2 activity are secondary caspase-dependent processes. This data also argues that GST- MDA-7 induces two parallel pro-apoptotic pathways via ROS-dependent and -independent mechanisms. Infection of primary human astrocytes with a recombinant adenovirus to express MDA-7, Ad.mda-7, but not infection with either Ad.cmv or Ad.mda-7SP- lacking MDA-7 secretion, resulted in the suppression of GBM cell colony formation in soft agar overlay assays, an effect that was enhanced in a greater than additive fashion by radiation. Collectively, our findings demonstrate that MDA-7 reduces proliferation and enhances the radiosensitivity of nonestablished human GBM cells in vitro, and when grown in 3 dimensions, and that sensitization occurs independently of basal EGFR/ERK1/2/AKT activity or the functions of PTEN and p53.
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PMID:MDA-7 regulates cell growth and radiosensitivity in vitro of primary (non-established) human glioma cells. 1532 89

Epirubicin HCl is a new anthracycline analog and derivative of doxorubicin. Doxorubicin is a potent anticancer agent, the use of which is limited by its cumulative dose-dependent cardiotoxicity. Epirubicin HCl has more favorable therapeutic index than doxorubicin and possesses less hematologic and cardiac toxicity at comparable doses. Hepatoma G2 cells are a valuable model to study hepatocellular carcinoma and the liver, where drugs are metabolized. The goal of our study was to evaluate the cytotoxic effect of epirubicin HCl on viability of Hep G2 cells measured using the MTT cytotoxicity test. Epirubicin HCl produced a concentration- and time-dependent cytotoxicity to Hep G2 cells. The mechanism of cytotoxicity of epirubicin HCl (IC(50) value of 1.6 mug/ml within 24 h) appeared to involve a production of free radical species since activities of free radical scavenging enzymes (SOD, catalase, Se-dependent GPx) were increased. Addition of SOD prevented cytotoxicity of epirubicin HCl, and also counteracted the apoptosis. DNA fragmentation was determined to evaluate apoptosis. Western blot analysis indicated a decrease in GST-pi expression and increased activity of NADPH-dependent cytochrome P450 reductase which is a major enzyme in the conversion of epirubicin HCl to a free radical. It is proposed that production of reactive oxygen species increased by the treatment with epirubicin HCl can cause lipid peroxidation, which subsequently promotes apoptosis and reduces cell viability. Superoxide dismutase, catalase and glutathione peroxidase must be considered as a part of the intracellular antioxidant defense mechanism of Hep G2 cells against single electron reducing quinone-containing anticancer antibiotics.
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PMID:Epirubicin HCl toxicity in human-liver derived hepatoma G2 cells. 1552 Apr 98

The objective of this study was to determine the anti cancer effects of red spinach (Amaranthus gangeticus Linn) in vitro and in vivo. For in vitro study, microtitration cytotoxic assay was done using 3-(4,5-dimethylthiazol-2-il)-2,5-diphenil tetrazolium bromide (MTT) kit assay. Results showed that aqueous extract of A gangeticus inhibited the proliferation of liver cancer cell line (HepG2) and breast cancer cell line (MCF-7). The IC(50) values were 93.8 mu g/ml and 98.8 mu g/ml for HepG2 and MCF-7, respectively. The inhibitory effect was also observed in colon cancer cell line (Caco-2), but a lower percentage compared to HepG2 and MCF-7. For normal cell line (Chang Liver), there was no inhibitory effect. In the in vivo study, hepatocarcinogenesis was monitored in rats according to Solt and Farber (1976) without partial hepatectomy. Assay of tumour marker enzymes such as glutathione S-transferase (GST), gamma-glutamyl transpeptidase (GGT), uridyl diphosphoglucuronyl transferase (UDPGT) and alkaline phosphatase (ALP) were carried out to determine the severity of hepatocarcinogenesis. The result found that supplementation of 5%, 7.5% and 10% of A. gangeticus aqueous extract to normal rats did not show any significant difference towards normal control (P <0.05). The exposure of the rats to chemical carcinogens diethylnitrosamine (DEN) and 2-acetylaminofluorene (AAF) showed a significant increase in specific enzyme activity of GGT, GST, UDPGT and ALP compared to normal control (P <0.05). However, it was found that the supplementation of A. gangeticus aqueous extract in 5%, 7.5% and 10% to cancer-induced rats could inhibit the activity of all tumour marker enzymes especially at 10% (P <0.05). Supplementation of anti cancer drug glycyrrhizin at suggested dose (0.005%) did not show any suppressive effect towards cancer control (P <0.05). In conclusion, A. gangeticus showed anticancer potential in in vitro and in vivo studies.
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PMID:Potential anticancer effect of red spinach (Amaranthus gangeticus) extract. 1556 47

Accumulating evidence suggests the concept that epirubicin and lymphokine-activated killer (LAK) cells cytotoxicity may be mediated by free radicals generation and P-glycoprotein-positive (Pg-p+) cancer cells are more sensitive for LAK cells than their drug-sensitive parental lines. We tested this hypothesis further by exposing drug-sensitive (WT) and epirubicin-resistant MCF-7 human breast tumor cells to epirubicin and LAK cells. Subsequently, we monitored cell proliferation as a measure of cytotoxicity. The cytotoxicity of epirubicin, LAK, and LAK + epirubicin (1/10 of IC50) was evaluated in 400-fold epirubicin resistant MCF-7 EPI(R) (P-glycoprotein overexpressing) and drug-sensitive MCF-7 WT cells. IC50 values were measured using the MTT cytotoxicity test. The MCF-7 EPI(R) cells exhibited an increased susceptibility to LAK cells than did the MCF-7 WT cells. P-gp+ MCF-7 EPI(R) cells were lysed by human LAK cells to a greater extend than were their drug-sensitive counterparts. LAK + epirubicin combined treatment increased susceptibility of MCF-7 WT and MCF-7 EPI(R) cells to LAK cells cytotoxicity. For both cell lines, cytotoxicity was dependent upon the concentration of the epirubicin and effector cell/target cell (E/T) ratio. The resistance of MCF-7 EPI(R) cells to epirubicin appears to be associated with a developed tolerance to superoxide, most likely because of a tree-fold increase in superoxide dismutase (SOD) activity and 13-fold augmented selenium dependent glutathione peroxidase (GSH-Px) activity. Acting in concert, these two enzymes would decrease the formation of hydroxyl radical from reduced molecular oxygen intermediates. The addition of SOD decreased cytotoxicity of epirubicin and LAK cells. Taken together, these observations support the role of oxygen radicals in the cytotoxicity mechanism of epirubicin and suggest further that the development of resistance to this drug by the MCF-7 EPI(R) tumor cells may have a component linked to oxygen free radicals. It is proposed that production of reactive oxygen species by the treatment of epirubicin and LAK cells can cause cytotoxicity of MCF-7 WT and MCF-7 EPI(R) cells. SOD, catalase, GSH-Px, GST (glutathione S-transferase), and GSH (reduced glutathione) must be considered as part of the intracellular antioxidant defense mechanism of MCF-7 WT and MCF-7 EPI(R) cells against reactive oxygen species.
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PMID:Combined effect of epirubicin and lymphokine-activated killer cells on the resistant human breast cancer cells. 1568 29

The ability of zinc to mobilize defense against reactive oxygen species (ROS) and H2O2-induced apoptosis was studied using a primary culture of rainbow trout gill cells. Gill cells were pretreated for 24 h with 100 microM ZnSO4 followed by 24-h exposure to 100 or 200 microM H2O2, or were subjected to 100 microM ZnSO4 together with 100 or 200 microM H2O2. Metallothionein-A (MTA) and metallothionein-B (MTB) mRNA levels were increased after treatment with zinc or H2O2, separately or in combination. Similarly, mRNA for glutathione S-transferase (GST) and glucose 6-phosphate dehydrogenase (G6PD) were increased in response to either zinc or H2O2, or after sequential treatments with zinc followed by H2O2. The stimulatory effects of zinc or H2O2 on MTA, MTB, GST, and G6PD mRNA levels could be blocked by addition of the membrane permeable zinc chelator, N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), suggesting that H2O2-induced upregulation of these genes is zinc-dependent. Pretreatment with zinc protected the cells from subsequent cell damage and apoptosis, as assessed by lactate dehydrogenase leakage, mitochondrial dehydrogenase activity (MTT assay), caspase-3 activity, and DNA fragmentation. In contrast, when gill cells were coincubated with zinc and H2O2 at the same time, H2O2 toxicity was higher than after treatment with H2O2 alone. It is concluded that zinc had a direct pro-oxidant effect when administered together with H2O2, but that pretreatment of zinc inhibited cytotoxicity and apoptosis through an indirect antioxidant action. We propose that the antioxidant action is manifested through zinc-dependent expression of several genes encoding antioxidant proteins (e.g., MTA, MTB, G6PD, and GST). Furthermore, the apparent zinc-dependency of H2O2-induced expression of antioxidant genes suggests that zinc might act as a physiological signal to mediate the response to oxidative stress.
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PMID:ZINC-mediated gene expression offers protection against H2O2-induced cytotoxicity. 1592 8

To elucidate the sensitivity of adenocarcinoma of the lung to cisplatin and irinotecan, intracellular glutathione (GSH) and glutathione S-transferase (GST)-pi concentrations and topoisomerase (topo) I activity were investigated using six adenocarcinoma cell lines. The antiproliferative activity was determined by MTT assay in terms of inhibition concentration (IC50) values. The IC50 values to cisplatin were not correlated with the amounts of intracellular GSH or GST-pi, but with intracellular accumulation of platinum (r = -0.91, p = 0.013). IC50 values to SN-38 were correlated with topo I activity determined by relaxation assay of pBR322 (r = -0.83, p = 0.040). These results suggest that platinum accumulation and topo I activity have definite impacts on the sensitivity of lung adenocarcinoma to cisplatin and irinotecan, respectively.
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PMID:Determinants of cisplatin and irinotecan activities in human lung adenocarcinoma cells: evidence of cisplatin accumulation and topoisomerase I activity. 1599 39

This study was aimed to investigate the changes of reactive oxygen species and antioxidative capacity on nitric oxide induced apoptosis in HL-60 cells. By means of in vitro incubation of HL-60 cells with sodium nitroprusside (SNP), the growth inhibition was detected by MTT assay. Cell morphology was observed by transmission electronmicroscopy and light microscopy. The apoptosis was analyzed by DNA agarose gel electrophoresis, DNA content and Annexin-V/PI labeling method. Reactive oxygen species (ROS) labeled with dihydrorhodamin 123 in cells was determinated by flow cytometry. The SNP-treated cells were examined for glutathione (GSH) level and activity of catalase (CAT), glutathione S-transferase (GST) and glutathione peroxidase (GPX). The results indicated that SNP could inhibit HL-60 cell growth. Cell apoposis was confirmed by typical cell morphology, DNA fragment, sub-G(1) phase and Annexin-V/PI labeling method. HL-60 cell apoptosis was induced by SNP in a dosage- and time-dependent manner. After exposing to SNP at the concentration of 0.5 - 3.0 mmol/L for 48 hours, the mean fluorescence intensity of ROS in cells was significantly higher than those in groups control and potassium ferricyanide (PFC). During the apoptosis process, level of ROS in cells increased, levels of GSH, CAT, GPTand GPX decreased. The significant dose-effect relationship existed between the levels of ROS, CAT, GST, GPX and SNP dose. It is concluded that change of intracellular reactive oxygen species and antioxidative capacity are an important factors during the process of SNP-induced apoptosis in HL-60 cell.
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PMID:[Change of reactive oxygen species and antioxidative capacity on nitric oxide induced apoptosis in HL-60 cells]. 1612 38

The object of the present study was to investigate the effect(s) of UV-B irradiation on the functional integrity, metabolic and detoxifying capacity of the isolated goat hepatocytes. Isolated goat hepatocytes were subjected to UV-B irradiation invitro for 0, 250, 500, 1250, 2500 and 7500 Joules/m2 which correspond to the irradiation time of 0, 1, 2, 5, 10 and 30 min. Cells were then analysed for Viability (Trypan blue exclusion test [TBE], 3-[4,5-dimethylthiozol-2yl]-2,5-diphenyltetrazolium bromide [MTT] assay, Membrane integrity (Lactate dehydrogenase [LDH] leakage, Lipid peroxidation) Detoxification (Ureagenesis, Cytochrome P450 activity [CYP450, Diazepam metabolism] and Glutathione-S-Transferase [GST] activity. The results show that there was no difference in functional, metabolic as well as detoxifying parameters of the hepatocytes when irradiated from 0-1250 Joules/m2, whereas a significant alteration was appreciable in the parameters such as LDH leakage, lipid peroxidation, and CYP450 activity when irradiated beyond 1250 Joules/m2. Our present findings suggest that the biologically compatible and feasible dose of UV-B irradiation for xenotransplantation appears to be 1250 Joules/m2.
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PMID:Effect of ultraviolet B (302 nm) irradiation on viability, metabolic and detoxification functions of goat hepatocytes--in vitro study. 1613 14

Resveratrol (3,4',5-trihydroxystilbene), a polyphenolic compound found in mulberries, grapes and red wine has been demonstrated to be capable of protecting against oxidative cardiovascular pathophysiology. However, the underlying cellular and biochemical mechanisms remain to be elucidated. This study was undertaken to determine if resveratrol could upregulate endogenous antioxidants and phase 2 enzymes in cultured aortic smooth muscle cells (ASMCs), and if such increased cellular defenses could provide protection against oxidative and electrophilic vascular cell injury. Incubation of rat ASMCs with resveratrol at low micromolar concentrations resulted in a significant induction of a scope of cellular antioxidants and phase 2 enzymes in a concentration- and/or time-dependent fashion. These cytoprotective factors include superoxide dismutase, catalase, glutathione, glutathione reductase, glutathione peroxidase, glutathione S-transferase (GST), and NAD(P)H:quinone oxidoreductase-1 (NOQ1). Notably, induction of catalase, GST, and NOQ1 was most remarkable among the above resveratrol-inducible antioxidants and phase 2 enzymes. Moreover, resveratrol treatment also significantly increased the mRNA expression of catalase, GSTA1, and NQO1 in a time-dependent manner. Pretreatment of ASMCs with resveratrol afforded a remarkable protection against xanthine oxidase (XO)/xanthine- or 4-hydroxy-2-nonenal-induced cytotoxicity, as assessed by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) reduction assay. Resveratrol pretreatment also led to a marked reduction in intracellular accumulation of reactive oxygen species in ASMCs after incubation with XO/xanthine. Taken together, this study demonstrates that a scope of key endogenous antioxidants and phase 2 enzymes in cultured ASMCs can be upregulated by resveratrol at low micromolar concentrations, and that such chemically-elevated cellular defenses rendered cells increased resistance to oxidative and electrophilic stress. The results of this study thus suggested a new mechanism, which might contribute to the cardiovascular protective effects of resveratrol.
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PMID:Upregulation of endogenous antioxidants and phase 2 enzymes by the red wine polyphenol, resveratrol in cultured aortic smooth muscle cells leads to cytoprotection against oxidative and electrophilic stress. 1616 43

Interleukin-2 is a vital cytokine secreted by activated T lymphocytes, and plays important role in the regulation of cellular and humoral immunity of animals. In our experiment, IL2 cDNA of the Tibet Pig was first cloned by RT-PCR from ConA-stimulated lymphocytes in the blood and subcloned into pMD-18 T vector, which then was identified with endonuclease restriction. The sequencing result showed that Tibet pig IL-2 (TPIL-2) cDNA was 503 bp long (ORF was 465 bp) (Genbank accession number: AY 294018). The recombinant prokaryotic and eukaryotic expression plasmids of the cDNA were then constructed to analyse the ability to stimulate the proliferation of porcine lymphocytes in vitro. The recombinant porcine IL-2 expressed in the prokaryotic cells was found to be of 43 kDa molecular mass, which was consistent with a 17.4 kDa protein deduced from the IL-2 cDNA sequence (glutathione S-transferase molecular mass is 26 kDa); the recombinant protein in eukaryotic cells was confirmed by use of specific rabbit anti-porcine IL-2 serum in an ELISA. The bioactivity of TPIL-2 was detected through MTT colorimetry by stimulating the proliferation of pig ConA-stimulated blasts in vitro. The results indicate that the TPIL-2 significantly promoted the proliferation of ConA-stimulated blasts of pig. This confirms that IL-2 cDNA of the Tibet pig was successfully cloned and expressed in prokaryotic and eukaryotic cells, which lays the foundation for the the preparation of specific recombinant IL-2 protein and development of novel immune adjuvants to raise the immunity of pigs against various infectious pathogens and increase the immunoprotective efficacy of vaccines.
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PMID:Molecular cloning and expression of IL2 cDNA from the Tibet pig. 1619 34


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