Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0345904 (liver cancer)
 15,188 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Assay conditions of human liver glutathione S-transferase and its activity in human serum from liver disease patients were investigated. One mmol/l reduced glutathione, and 1 mmol/l-1-chloro-2,4-dinitrobenzene, pH 6.5, were used for the measurement, because of the very low non-enzymatic conjugation. Glutathione S-transferase activity was inhibited by bilirubin, but this inhibition was counteracted by the presence of a low concentration of albumin. The normal human serum glutathione S-transferase activity was 5.2 +/- 2.4 I.U./l (mean +/- S.D.), and was not influenced by any differences of age, sex or leukocyte count. A significant increase in serum enzyme activity was noted in cases of acute hepatitis with GPT exceeding 200 I.U./l, primary hepatoma and metastatic liver cancer. Some of the cases with fulminant hepatitis showed extremely high values. The degree of correlation between serum glutathione S-transferase and GOT or GPT was high in acute hepatitis, with GOT or GPT exceeding 200 I.U./l, in fulminant hepatitis, primary hepatoma and gall stones, while in chronic hepatitis and liver cirrhosis it was low. In cases of acute hepatitis and fulminant hepatitis, the disappearance of serum glutathione S-transferase from the blood was much faster than that of GOT and GPT. Serum glutathione S-transferase measurements will provide new and unique information for the diagnosis of acute liver diseases.
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PMID:Serum glutathione S-transferase activity in liver diseases. 625 85

Glutathione S-transferase (GST) and carcinoembryonic antigen were measured in the plasma of 95 patients with neoplasm of digestive tract, in 40 patients suffering from non-neoplastic diseases and in 40 healthy subjects. The mean value of the GST activity was significantly (P < 0.001) elevated in patients with gastric, liver and colorectal cancer (10.4 U/l, 14.1 U/l and 12.3 U/l respectively) as compared with the reference population (3.2 U/l). GST elevations above normal were observed in 26 (90%) patients with gastric cancer, in 18 (100%) with liver cancer and in 25 (89%) with colorectal cancer. Carcinoembryonic antigen appeared less sensitive. In 15 patients the postoperative levels of serum GST were increased after surgery then gradually declined and after 1 month showed a normalization in 10 patients. Our data suggest that GST measurement may be useful as a tumour marker in gastric, liver and colorectal cancer. Moreover the combined determination of GST and other markers increase the sensitivity for cancer detection.
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PMID:Glutathione S-transferase activity in patients with cancer of the digestive tract. 827 May 99

Oltipraz [5-(2-pyrazinyl)-4-methyl-1,2-dithiole-3-thione] protects against aflatoxin B1-induced hepatocarcinogenesis in rats when fed before and during carcinogen exposure; however, such an exposure-chemoprotection intervention paradigm is not directly relevant to most human populations. To model and assess the possible efficacy of short term interventions targeted at individuals at risk for sustained exposure to aflatoxins, 175-g male F344 rats were treated daily with 25 micrograms of aflatoxin B1, p.o., for 28 days. One week after the start of aflatoxin B1 exposure, half of the animals were fed a diet supplemented with 0.075% oltipraz for 10 days; these rats were then restored to the unsupplemented AIN-76A diet for the remainder of the experimental period. Livers were analyzed 2 or 3 months after the last aflatoxin B1 dose for burden of glutathione S-transferase P (GST-P)-positive foci, as an index of presumptive preneoplastic tumors. The transient intervention with oltipraz reduced the volume percent of hepatic GST-P-positive foci by 54% (P = 0.047) and 72% (P = 0.004) at 2 and 3 months, respectively. A strong positive correlation was also observed between the extent of fibrosis in the livers of these animals and the hepatic burden of GST-P-positive foci, implying that cytotoxicity is associated with the tumorigenic process. This protection may reflect alterations in the metabolism and disposition of aflatoxin B1 induced by oltipraz. Glutathione S-transferase catalyze the detoxication of aflatoxin-8,9-oxide and were found to be rapidly induced in the livers of animals after the beginning of the oltipraz intervention. Glutathione S-transferase activity remained significantly (P < 0.05) higher until 9 days after the end of the oltipraz intervention. In contrast, levels of hepatic aflatoxin-DNA adducts were not significantly reduced until 4 days after the beginning of the intervention but remained significantly (P < 0.05) lower up to 11 days after the end of the intervention. The cumulative reduction in levels of hepatic aflatoxin-DNA adducts (approximately 25%) by the oltipraz intervention underestimated the reduction in the hepatic burden of GST-P-positive foci. The significant protection against presumptive preneoplastic tumors, despite the delay of intervention, suggests that oltipraz may exert substantial activity against the cytotoxic and autopromoting action of repeated exposures to aflatoxin B1 and supports the utility of intervention trials with oltipraz in individuals chronically consuming aflatoxin B1-contaminated foods, particularly in regions with high incidences of liver cancer.
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PMID:Transient intervention with oltipraz protects against aflatoxin-induced hepatic tumorigenesis. 833 53

Hepatitis B virus X protein (HBx) is a transcriptional coactivator that plays a significant role in the regulation of genes involved in inflammation and cell survival. A recently identified cellular coactivator, activating signal cointegrator 2 (ASC-2), is enriched in liver cancer cells and associates with many transcription factors that are active in hepatocytes. The tissue colocalization of these 2 proteins, in view of their similar regulatory functions, led us to examine whether HBx and ASC-2 cooperate in transcriptional activation of gene expression. Glutathione S-transferase (GST) pull-down assays and mammalian 2-hybrid analysis show that the transactivation domain of HBx interacts with the C-terminal domain of ASC-2. In fact, these 2 proteins associated in a ternary complex that included the transcriptional activator retinoid X receptor (RXR). Mechanistically, on expression of HBx, the half-life of the ASC-2 coactivator is observed to increase in concordance with the observed increase in ASC-2-dependent coactivation of transcription. In conclusion, these results show that HBx stabilizes the cellular coactivator ASC-2 through direct protein-protein interaction, affecting the regulation of genes actively transcribed in liver cancer cells.
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PMID:Hepatitis B virus X protein regulates transactivation activity and protein stability of the cancer-amplified transcription coactivator ASC-2. 1457 65

Glutathione S-transferase (GST) family members promote carcinogenesis and cancer progression. We assessed GST pi 1 (GSTP1) mRNA and protein levels in hepatocellular carcinoma (HCC) using genome databases and tissue microarray (TMA) technology. We found that in cancerous tissues, GSTP1 mRNA was down-regulated in genome databases, and immunohistochemical staining of GSTP1 in 237 HCC cases varied from negative to strongly positive. GSTP1 levels correlated negatively with tumor size and serum alpha-fetoprotein (AFP) in HCC patients, and higher GSTP1 levels associated with longer overall survival (OS) and disease-free survival (DFS). We also found that GSTP1 overexpression restrained HepG2 and Huh7 liver cancer cell proliferation in vivo and in vitro. GSTP1 arrested the cell cycle at G1/S by up-regulating p21 and p27 and down-regulating p-Akt. Interrupting GSTP1 gene expression promoted liver cancer cell proliferation and increased the percentage of cells in S phase by decreasing levels of p21 and p27 and increasing p-Akt. These results suggest high GSTP1 levels provide a better prognosis through suppression of tumorigenesis in HCC.
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PMID:High GSTP1 inhibits cell proliferation by reducing Akt phosphorylation and is associated with a better prognosis in hepatocellular carcinoma. 2950 66

Glutathione S-transferase (GST) family members play an important role in detoxification, metabolism and carcinogenesis. The aim of this study is to investigate the effect of Glutathione S-transferase A1 (GSTA1) on the prognosis of HCC and to understand its role in tumor progression and the possible mechanism. GSTA1 in HCC was assessed using immunohistochemical staining, and it was found that HCC patients with better pathological differentiation had higher GSTA1 abundance. Further, high GSTA1 expression was correlated with low AFP, absent PVTT, and early stage TNM for HCC patients. Higher GSTA1 indicated longer overall survival and disease-free survival, while lower GSTA1 indicated poorer prognosis. Subsequently, lentiviral vector carrying GSTA1 gene was successfully constructed and maintained high expression in 97H and SNU449 liver cancer cells. We found that high GSTA1 restrained liver cancer cell proliferation, migration and invasion in vitro. Western blot showed that LKB1 and p-AMPK were upregulated while p-mTOR, p-p70 S6 Kinase and MMP-9 were downregulated in high GSTA1 groups. Taken together, high GSTA1 correlated with satisfactory prognosis of HCC. Additionally, GSTA1 may act as a protective factor through suppression of tumorigenesis by targeting AMPK/mTOR in HCC.
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PMID:Glutathione S-transferase A1 suppresses tumor progression and indicates better prognosis of human primary hepatocellular carcinoma. 3189 75