Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The incidence and phenotype of preneoplastic and neoplastic liver lesions appearing in LEC rats after recovery from severe hereditary hepatitis were studied in comparison with the liver lesions appearing in chemical liver carcinogenesis. The livers of 168 rats (90 male, 78 female) were stained for seven histochemical markers at different time periods from the 20th week to the 122nd week of life. Glucose-6-phosphatase (G6Pase), adenosine triphosphatase (ATPase) and non-specific esterase (ES) were used as negative markers. Gamma-glutamyltransferase (GGT), glutathione S-transferase placental form (GSTP), esterase isozyme L-1 (L1) and alpha-fetoprotein (AFP) were used as positive markers. The study on the incidence of liver lesions in the LEC rats revealed sequential development of liver foci, nodules and hepatocellular carcinomas (HCCs) similar to those seen in chemically induced liver carcinogenesis. These lesions appeared earlier and more frequently in male LEC rats than in female ones, suggesting the importance of hormonal environment in spontaneous HCC development. The histochemical analysis of spontaneous liver lesions in LEC rats showed that GSTP was the most reliable positive marker as previously reported in chemical liver carcinogenesis. There was no essential difference in the expression of the markers in spontaneous and chemically induced liver lesions except for L1, which is considered to be related to xenobiotic metabolism. The results of this study suggest that both spontaneous and chemically induced liver cancer may develop by passing through phenotypically similar preneoplastic processes. In addition, the LEC rat uniquely showed chronic liver damage (hepatocyte death and regeneration) at the promotion stage of carcinogenesis. Such a natural history of HCC development in LEC rats is similar to that of human HCC which is frequently associated with chronic liver damage. Thus, the LEC rat provides a useful model for studying the process and underlying mechanisms of human liver cancer development.
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PMID:Phenotype of preneoplastic and neoplastic liver lesions during spontaneous liver carcinogenesis of LEC rats. 169 69

The process of chemical hepatocarcinogenesis is characterized by the appearance of preneoplastic lesions showing changes in the expression of various marker enzymes. We have analyzed the phenotype of small preneoplastic foci and expansively growing nodules in liver sections obtained from rats treated with various carcinogens. Changes within the lesions in canalicular adenosine triphosphatase, gamma-glutamyl transpeptidase, NADPH-(cytochrome P-450) reductase, cytochrome P-450 PB2, epoxide hydrolase, and glycogen content were detected by means of enzyme histochemical and immunohistochemical staining procedures. In parallel sections the expression of albumin messenger RNA was investigated by in situ hybridization using a 35S-labeled albumin specific complementary DNA probe. In general, small preneoplastic lesions showed unchanged levels of albumin messenger RNA. In contrast, the expression of albumin messenger RNA was found to be reduced to varying degrees in large hepatic nodules. An expression of alpha-fetoprotein messenger RNA could not be detected in any of the nodules. No direct correlation between the enzyme phenotype of the lesions and the degree in reduction of albumin messenger RNA could be established except that the reduction was most pronounced in nodules which had lost their ability to store glycogen. Since the synthesis and excretion of albumin is a typical function of the differentiated hepatocyte in the adult animal, the observed decrease in albumin messenger RNA expression in large hepatic nodules is in accordance with the hypothesis of a gradual dedifferentiation or retrodifferentiation of the cell population during carcinogenesis. Hyperplastic nodules produced by continuous treatment of rats with 4-dimethylaminoazobenzene showed increased rather than decreased albumin levels. The analysis of albumin messenger RNA expression might therefore be used as a tool to discriminate between nodules of differing biological nature and fate.
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PMID:Expression of albumin messenger RNA detected by in situ hybridization in preneoplastic and neoplastic lesions in rat liver. 242 87

PLC/PRF/5, a tissue culture cell line derived from a human hepatocellular carcinoma and producing hepatitis B surface antigen (HBsAg), was studied by immune and enzyme histochemical techniques. HBsAg was demonstrated in the cytoplasm and on the surface of tumor cells. The percentage of HBsAg-positive cells in subculture increased with time until almost all cells expressed HBsAg when the monolayer reached confluence. Similar patterns were found for alpha 1-anti-trypsin and carcino-embryonic antigen, whereas alpha-fetoprotein was observed only in small foci of cells. Hepatitis B core antigen and albumin were not detected. gamma-Glutamyl transferase activity was markedly increased in the tumor cells, whereas adenosine triphosphatase and glucose-6-phosphatase activities were not demonstrable. Patterns of antigenic expression and enzyme phenotype of PLC/PRF/5 cells show remarkable resemblance to those observed in vivo in human hepatocellular carcinoma. Therefore, this cell line may be a useful model to study the control and modulation of both oncofetal antigens and HBsAg.
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PMID:Immune and enzyme histochemical studies of a human hepatocellular carcinoma cell line producing hepatitis B surface antigen. 616 57