Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ten-fold increase in glucose-6-phosphatase, previously reported, in 2S FAZA hepatoma cells exposed to dexamethasone, is completely blocked by low concentrations of insulin. At 3 x 10(-10) M insulin, the activity induced by 10(-6) M dexamethasone is reduced by half. The activity of intact microsomes, which reflects translocation of cytoplasmic glucose 6-phosphate into the endoplasmic reticulum, is induced by dexamethasone, but to a lesser extent than the hydrolase. Insulin also prevents this induction.
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PMID:Effect of insulin on the induction by dexamethasone of glucose-6-phosphohydrolase and translocase activities in cultured hepatoma cells. 283 6

The concentration of serum immunoreactive prolyl 4-hydroxylase (S-IRPH) was determined in patients with various liver diseases by the radioimmunoassay developed previously. S-IRPH values were elevated in acute hepatitis (p less than 0.01), hepatocellular carcinoma (p less than 0.05), metastatic liver neoplasm (p less than 0.01) and cholestatic diseases (p less than 0.001), but no significant elevation was seen in chronic hepatitis or liver cirrhosis. The mean value of S-IRPH was highest in cholestatic diseases, and next highest in acute hepatitis. In addition to acute hepatitis, S-IRPH was increased in other conditions of hepatocellular damage such as exacerbation of chronic hepatitis or immediately after transcatheter arterial embolization of hepatocellular carcinoma. In cases of hepatocellular damage S-IRPH varied concurrent with cytoplasmic enzyme (AST, ALT and LDH) levels and in cases of cholestatic diseases with biliary enzyme (Al-P and gamma GTP) levels. These properties appear to be unique among serum enzymes. The characteristics of S-IRPH were considered to be related to its unique subcellular localization within the cell, ie the membrane of rough endoplasmic reticulum.
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PMID:Studies on serum immunoreactive prolyl 4-hydroxylase in liver diseases--its elevation both in hepatocellular damage and cholestatic diseases. 284 41

Using light and ultrastructural immunoperoxidase techniques, we examined the distribution of hepatitis B virus (HBV)-associated antigens and the subcellular localization of hepatitis B surface antigen (HBsAg) in liver biopsies of HBsAg-positive patients with cirrhosis. The localization patterns of HBsAg in hepatocytes were membranous, cytoplasmic, festoon and inclusion body types. Cytoplasmic and festoon types were seen more often than the membranous type in pseudolobules, and hepatitis B core antigen (HBcAg)-positive cells with cytoplasmic type were distributed in the periphery of pseudolobules with active inflammation. Immunoelectron microscopy in the cytoplasmic or festoon type of HBsAg showed immunoreaction in the cisternae and on virus-like particles in the cisternae in patients with hepatitis B e antigen (HBeAg) antigenemia. Simultaneous staining of HBsAg and HBcAg revealed that hepatocytes with cytoplasmic or festoon type of HBsAg contained HBcAg-immunoreactivity. The inclusion body type of HBsAg was characteristic of liver cirrhosis with hepatocellular carcinoma (HCC); the subcellular localization of HBsAg was seen in clusters of the endoplasmic reticulum around the nucleus, and HBsAg-immunoreactivity was observed on many virus-like particles in most of the cisternae in those with HBeAg antigenemia. These findings suggest that the synthesis of HBsAg is active in patients with liver cirrhosis and that the formation of HBV is also active in those with HBeAg antigenemia and that HBV may be retained more in cirrhotic livers with hepatocellular carcinoma after proliferation than in those without it.
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PMID:Immunocytochemical investigation of hepatitis B virus-associated antigens in cases of liver cirrhosis and HBsAg antigenemia and their relationship to development of hepatocellular carcinoma. 285 Feb 88

Firstly, using HCC cell lines, the effects of r-h TNF were investigated. The authors had already confirmed that these cell lines were derived from human HCC. Each cell line showed a different growth curve on addition of TNF to the culture medium. JHH-4 exhibited enhancement of growth under the optimum concentration of TNF. On the other hand, growth of JHH-5 and JHH-7 was inhibited by TNF. JHH-7 were more sensitive to TNF than JHH-5, however, the direct effect of TNF on JHH-7 was not potent, as 10(4) u/ml TNF could not prevent proliferation of JHH-7. Morphological examinations were also performed. Phase-contrast microscopy showed that the JHH-4 cells were enlarged and tended to pile up after the addition of TNF to the culture medium. JHH-7 cells became detached from the culture dish due to cell death. Electron microscopy showed irregular proliferation of the rough endoplasmic reticulum of JHH-4 cells and increased number of lysosomes in JHH-7 cells. Furthermore, hyperthermia exhibited an interesting reciprocal action. Proliferation of JHH-4 was inhibited by low concentrations of TNF together with 41.4 degrees C hyperthermia in contrast to the effects of TNF alone. JHH-7 became more sensitive to TNF under hyperthermia at 41.4 degrees C. On the other hand, normal human fibroblast 'HAIN-55' were not affected by TNF at 37.0 degrees C, 41.4 degrees C or 42.5 degrees C. In this paper, the authors tried to study the effects of TNF and hyperthermia on human HCC cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Effects of TNF on human hepatocellular carcinoma cell lines and their modification by hyperthermia]. 285

The histochemical characteristics of liver cell foci in woodchucks were investigated. The foci appeared to be distributed throughout the liver and were observed only in the woodchuck hepatitis virus (WHV)-positive animals, including all 19 woodchucks with hepatocellular carcinoma(HCC), and 7 without HCC. No foci appeared in 11 WHV-negative animals. Histochemical studies revealed that liver cell foci and carcinoma cells were characterized by positive gamma-glutamyl transpeptidase (GGT) enzymatic reactions and decreased glucose-6-phosphatase enzyme activity compared to non-neoplastic liver. Furthermore, serum GGT was significantly elevated in almost all of the animals which had larger carcinomas. Ultrastructural findings of foci showed some resemblance to carcinoma cells, being characterized by abundant free ribosomes within the cytoplasm and undeveloped endoplasmic reticulum. These results suggest that the liver cell foci are potential precursors of HCC in WHV-infected animals, and that serum GGT may be a useful marker for indicating the development of carcinoma.
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PMID:Enzyme-altered liver cell foci in woodchucks infected with woodchuck hepatitis virus. 289 65

A cDNA library from the human hepatoma cell line Hep G2 was prepared in the expression vector lambda gt11. Using specific antibodies, a cDNA clone containing the entire coding sequence for the human asialoglycoprotein receptor was isolated and sequenced. The deduced amino acid sequence of 291 residues is very homologous to the sequence of the major asialoglycoprotein receptor protein from rat. The comparison shows that there is no significant post-translational processing and no leader sequence, cleaved or uncleaved, at the amino terminus. An internal signal sequence, probably the membrane-spanning segment, residues 41-59, is assumed to direct insertion of the carboxyl-terminal ligand binding portion of the receptor across the endoplasmic reticulum membrane.
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PMID:Sequence of human asialoglycoprotein receptor cDNA. An internal signal sequence for membrane insertion. 298 98

The synthesis and structure of the primary translation product of apo AII in a human liver poly(A+) mRNA primed cell-free system and its cotranslational modification was studied parallel to studies in vivo with Hep G2 cells, a human hepatoma cell line. The primary translation product is a preproprotein containing 100 amino acid residues, which is cleaved by the signal peptidase of endoplasmic reticulum to pro-apo AII with the loss of the N-terminal pre-sequence consisting of 18 amino acid residues. Hep G2 cells contain about equal amounts of the proform of apolipoprotein AII and of mature apo AII. Approximately in the same ratio pro- and mature apo AII are secreted into the medium. Determination of the partial amino-acid sequence by automated Edman degradation of the labelled prepro- and proforms of apo AII led to the segmentation of the N-terminus of the primary translation product, consisting of 23 amino acid residues, into the pre-sequence (18 residues) and the pro-sequence (5 residues) with terminal Arg-Arg-residues at the cleavage site to apo AII. We must therefore correct our previously postulated 17 and 6 residues containing segmentation. So far no information has been obtained in which compartment and at what stage of posttranslational events the dimerization occurs by formation of the single disulfide bond at position Cys6 in the mature apo AII structure, leading to the symmetrical molecule.
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PMID:Synthesis and processing of human serum apolipoprotein AII in vitro and in Hep G2 cells. 298 98

Male Wistar rats were treated by 9 i.p. injections with 100 mg/kg body weight diethylnitrosamine (DEN), in 9 consecutive weeks. After decapitation, between the 130th and 140th day, primary hepatocellular carcinomas were found. Tissue from 3 different parts of the liver was processed to study the activity of Glucose-6-Phosphatase in the membranes of the endoplasmic reticulum, Adenosinetriphosphatase in the cell (plasma) membrane and of Succinic-Dehydrogenase in mitochondrial membranes. In the experimental animals liver tissue revealed no activity of G-6-P in any region affected by the tumor. ATP and SDG activity was dependent on the type of lesion. Generally speaking it diminished with the lesser differentiation of the hepatoma cells. Other morphological and metabolic aspects of liver DEN cancerogenesis are discussed.
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PMID:Membrane enzyme cytochemical changes in the hepatocytes of diethylnitrosamine induced hepatomas. 298 80

An immunocolloidal gold electron microscopy method is described allowing the ultrastructural localization and quantitation of the regulatory subunits RI and RII and the catalytic subunit C of cAMP-dependent protein kinase. Using a postembedding indirect immunogold labeling procedure that employs specific antisera, the catalytic and regulatory subunits were localized in electron-dense regions of the nucleus and in cytoplasmic areas with a minimum of nonspecific staining. Antigenic domains were localized in regions of the heterochromatin, nucleolus, interchromatin granules, and in the endoplasmic reticulum of different cell types, such as rat hepatocytes, ovarian granulosa cells, and spermatogonia, as well as cultured H4IIE hepatoma cells. Morphometric quantitation of the relative staining density of nuclear antigens indicated a marked modulation of the number of subunits per unit area under various physiologic conditions. For instance, following partial hepatectomy in rats, the staining density of the nuclear RI and C subunits was markedly increased 16 h after surgery. Glucagon treatment of rats increased the staining density of only the nuclear catalytic subunit. Dibutyryl cAMP treatment of H4IIE hepatoma cells led to a marked increase in the nuclear staining density of all three subunits of cAMP-dependent protein kinase. These studies demonstrate that specific antisera against cAMP-dependent protein kinase subunits may be used in combination with immunogold electron microscopy to identify the ultrastructural location of the subunits and to provide a semi-quantitative estimate of their relative cellular density.
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PMID:Localization of nuclear subunits of cyclic AMP-dependent protein kinase by the immunocolloidal gold method. 299 18

The synthesis and secretion of apolipoprotein B-100 (apoB-100) have been studied in a human hepatoma cell line, the Hep G2 cells. The time needed for the synthesis of apoB-100 was estimated to be 14 min, which corresponds to a translation rate of approximately 6 amino acids/s. ApoB-100 was compared with albumin and alpha 2-macroglobulin as to the distribution between the membrane and the luminal content in the endoplasmic reticulum (ER) and the Golgi apparatus. The results suggested that apoB-100 approximately followed the distribution of these secretory proteins in the Golgi, while the ratios between the percent membrane-bound apoB-100 and percent membrane-bound albumin or alpha 2-macroglobulin were 3-4:1 in the ER. This may suggest that apoB-100 occurs in a membrane-associated form in ER prior to the integration in the lipoproteins. Pulse-chase studies combined with subcellular fractionation was used to investigate the kinetics for the intracellular transfer of apoB-100. A 3-min pulse of [35S]methionine was followed by an increase in apoB-100 radioactivity in the ER during the first 10-15 min of chase. The following 10-15 min of chase were characterized by linear decrease in apoB-100 radioactivity with a decay rate of approximately 6%/min. The residence kinetics for apoB-100 in the ER differed from that of transferrin and probably also from that of albumin. By comparing the time for the pulse maximum in ER with that in the denser Golgi fractions the time needed for the transfer between ER and Golgi could be estimated to be 10 min. The time needed for the secretion of newly synthesized apoB-100 was estimated to be 30 min. This indicates that the transfer of the protein through the Golgi apparatus to the extracellular space requires 20 min.
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PMID:Pulse-chase studies of the synthesis and intracellular transport of apolipoprotein B-100 in Hep G2 cells. 302 51


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