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)

Fibronectin is a family of immunologically similar glycoproteins which mediate a variety of cell-cell and cell-substratum interactions. It is a constituent of the extracellular matrix of connective tissue and circulates in plasma. When suspension and adherent cultures of a human hepatoma cell line (SK-HEP-1) were incubated in serum-free medium, the resulting conditioned medium contained material which was specifically immunoprecipitated by antisera to human plasma fibronectin. By double immunodiffusion, a component in the conditioned culture medium was shown to form a line of identity with fibronectin in human plasma and to migrate as an alpha 2- to beta-globulin during immunoelectrophoresis. Human fibronectin was quantified in conditioned medium by electroimmunodiffusion, and was found to increase for at least three days at about 0.1 micrograms/10(6) cells/day. Adherent cultures of SK-HEP-1 cells were incubated with L-[35S]methionine to label newly synthesized proteins. Labeled fibronectin in conditioned medium or in cell extracts comigrated with fibronectin in human plasma as shown by autoradiography following crossed-immunoelectrophoresis. Fibronectin was demonstrated in the extra-cellular matrix of adherent SK-HEP-1 cultures by immunofluorescence. We had shown previously that SK-HEP-1 cells synthesize alpha 1-protease inhibitor, one of the products of normal hepatocytes. The finding that these hepatoma cells also synthesize fibronectin supports the concept that the hepatocyte may be one source of circulating fibronectin, a possibility consistent with the established role of this cell type in blood plasma protein synthesis.
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PMID:Fibronectin synthesized by a human hepatoma cell line. 632 32

Percutaneous needle biopsy specimens of the liver from three elderly persons (aged 77, 71, and 66) demonstrated eosinophilic intracytoplasmic globules within hepatocytes, particularly in the periportal and periseptal areas. These globules were periodic acid-Schiff positive and diastase resistant, and were identified as alpha-1-antitrypsin by immunofluorescence technics. Two of the patients had cirrhosis, and identification of protease inhibitor (Pi) type by acid starch electrophoresis and crossed immunoelectrophoresis demonstrated SZ and MZ genotypes. The patient with SZ genotype also had a long history of chronic obstructive pulmonary disease. Pi-typing was not performed for the third patient, who did not have cirrhosis. The morphologic identification of alpha-1-antitrypsin disease in liver biopsies of persons of any age is important because of (1) possible multisystem involvement (hepatic and pulmonary), (2) increased frequency of hepatocellular carcinoma, and (3) implications for genetic counseling for other family members.
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PMID:Alpha-1-antitrypsin globules in hepatocytes of elderly persons with liver disease. 701 69

The Hep G2 hepatoma cell line synthesizes the inter-alpha-trypsin inhibitor (ITI). This protease inhibitor and the other proteins of this family include four polypeptides chains: three heavy chains (HC1, HC2, HC3) and one light chain (bikunin). In the present study, we have demonstrated by immunofluorescence that ITI is detected mainly in perinuclear cytoplasmic zones comparable to those of albumin or alpha-1-antitrypsin. The presence of the mRNAs of the four polypeptide chains in all Hep G2 cells of a non-synchronized culture have been demonstrated by in situ hybridization. An evaluation of the transcription of the four ITI genes through an analysis of markings brings to the fore a clearly much higher rate of mRNAs from the light chain than from the heavy chains. The mRNAs corresponding to the HC2 chains are more heavily represented than are those corresponding to the HC1 and HC3 chains. In Hep G2 cells in culture, a quantification of mRNAs based on the in situ hybridization technique shows that their relative quantities, in decreasing order, are those of L, HC2, HC3 and HC1.
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PMID:Light microscopical detection of inter-alpha-trypsin inhibitor and its different mRNAs in cultured hepatoma Hep G2 cells using immunocytochemical and in situ hybridization techniques. 751 68

Previous studies of murine serum amyloid A (SAA) regulation during inflammatory states or following exposure to macrophage-conditioned medium have raised the possibility that both post-transcriptional and transcriptional mechanisms participate in induction of this family of proteins. Since IL-6 and IL-1 have been shown to induce SAA in human hepatoma cell lines, we explored the possibility that these cytokines might induce human SAA through post-transcriptional as well as transcriptional mechanisms. In kinetic studies, we found that continuous exposure of Hep 3B cells to either IL-6 or IL-1 beta alone caused only minimal increases in SAA mRNA and marginal increases in transcription (as measured by nuclear runon). In contrast, the combination of these cytokines led to a 23-fold increase in transcription, maximal at 12 h, with continuing increase in mRNA, achieving levels more than 1,000-fold greater than baseline by 72 h. This massive disparity between increases in mRNA and in transcription rate strongly supports the participation of post-transcriptional mechanisms in SAA induction by (IL-6 + IL-1 beta), whereas the lag between peaks of transcription and mRNA abundance reflects a relatively slow degradation rate of SAA mRNA. As observed by other workers, mean size of SAA mRNA decreased progressively over the course of incubation. Simultaneous kinetic studies of complement factors B and C3, haptoglobin, and alpha-1 protease inhibitor revealed several different patterns of response to IL-6 and IL-1 beta.
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PMID:Induction of human serum amyloid A in Hep 3B cells by IL-6 and IL-1 beta involves both transcriptional and post-transcriptional mechanisms. 781 86

The HuH-7 human hepatoma cell line was stimulated by IL-1 and IL-6 to increase the synthesis of acute-phase proteins, e.g. serum amyloid A (SAA), alpha 1 antichymotrypsin (ACT), alpha 1-protease inhibitor, alpha 1 acid-glycoprotein and haptoglobin, with the exception of the pentraxins (serum amyloid P and C-reactive protein). Haptoglobin and ACT were stimulated by IL-1 which has not been observed in some other hepatoma cell lines. The concentration of IL-1 required for stimulation of SAA was higher than that required for haptoglobin stimulation. IL-1 receptor antagonist was capable of inhibiting these responses and acted at a lower concentration to inhibit SAA than required to inhibit ACT or haptoglobin induction. Transforming growth factor beta (TGF beta) was also able to inhibit the response to IL-1 but had no effect on acute-phase protein responses to IL-6.
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PMID:Inhibition of the acute-phase response in a human hepatoma cell line. 839 Dec 2

Hepatocytes respond to inflammatory stimuli by changing the synthesis and N-glycosylation of acute phase plasma proteins (APP). So far, interleukin (IL) 6, transforming growth factor beta (TGF beta), tumor necrosis factor alpha (TNF) and IL-1 have been found to control N-glycosylation patterns of APP. Cytokines either increased (type I) or decreased (type II) the ratio of bi-relative to more branched N-glycans on APP. In this study, we describe the effect of leukemia inhibitory factor (LIF), interferon gamma (INF gamma) and dexamethasone (dex) on production of alpha 1-protease inhibitor (PI) and alpha 1-antichymotrypsin (ACT) and on glycosylation of PI in the human hepatoma cell line HepG2. Cytokines and dex were used separately and in various combinations including also IL-6 and TGF beta. Production of the antiproteases was quantitated by immunoelectrophoresis of the proteins accumulated in the culture medium. Glycosylation pattern of PI was assessed by crossed immunoaffinity electrophoresis (CIAE) with Concanavalin A (Con A) as a ligand. The production of ACT and PI was increased by LIF, decreased by INF gamma and unaffected by dex. LIF and INF gamma each like IL-6, decreased PI-Con A reactivity while dex like TGF beta enhanced PI-Con A reactivity. Combination of dex with LIF yielded additive effects while combination of dex with either INF gamma, L-6 or TGF beta acted synergistically on PI-Con A reactivity. Combinations of multiple cytokines and dex produced additive, inhibitory or synergistic effects. The type of glycosylation profile of PI secreted by HepG2 cells depended on the composition and amounts of interacting cytokines and dex.
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PMID:Leukemia inhibitory factor, interferon gamma and dexamethasone regulate N-glycosylation of alpha 1-protease inhibitor in human hepatoma cells. 839 65

1. alpha 1-antitrypsin is an antiprotease that inhibits the neutrophil elastase enzyme, and belongs to a family of structurally related serine proteinase inhibitors (serpins). Its methionine358 residue determines the specificity for elastase. 2. The normal M-type alpha 1-antitrypsin is mainly synthesized in the liver parenchymal cells and transported to the plasma. Abnormal Z-mutant alpha 1-antitrypsin is retained in the endoplasmic reticulum, which leads to its intracellular accumulation and to markedly decreased plasma levels. 3. In normal conditions, alpha 1-antitrypsin protects the lungs from destruction by the proteolytic neutrophil elastase. A protease/antiprotease imbalance in the lung is responsible for the development of emphysema in severe alpha 1-antitrypsin deficiency and in cigarette smokers, and accounts for the marked acceleration of the lung disease in smoking alpha 1-antitrypsin deficient patients. Smoking has to be avoided in alpha 1-antitrypsin deficient patients. Replacement therapy with plasma-derived alpha 1-antitrypsin seems indicated in alpha 1-antitrypsin deficient patients with emphysema. 4. Intracellular accumulation of abnormal Z-alpha 1-antitrypsin molecules in liver parenchymal cells may lead to liver disease, ranging from neonatal cholestasis to adulthood cirrhosis and hepatocellular carcinoma. End-stage liver disease can be treated by liver transplantation, which is followed by a phenotypic conversion. 5. Diagnosis of alpha 1-antitrypsin deficiency related disease relies on the presence of a low serum concentration of alpha 1-antitrypsin, and of periodic-acid Schiff positive globules in the liver parenchymal cells. Isoelectric focusing of the serum identifies the protease inhibitor phenotype. The protease inhibitor phenotype is determined by the independent expression of the two parental alpha 1-antitrypsin alleles. It is determinant of the serum level and of the risk for development of lung or liver disease.
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PMID:Alpha 1-antitrypsin deficiency: an overview. 839 99

Induction of PAI-2 by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been studied in human primary hepatocytes, hepatoma HepG2 cells and monocytic U937 cells, extending recent findings in human keratinocytes. PAI-2 represents a serpine-type protease inhibitor with wide-ranging implications in fibrinolysis, extracellular matrix proteolysis, growth factor activation and carcinogenesis. PAI-2 was induced by >10(-9) M TCDD in hepatocytes and HepG2 cells and by >10(-10) M TCDD in U937 cells. In the latter cell line, PAI-2 induction by TCDD and by 12-O-tetradecanoyl phorbol-13-acetate (TPA) has been compared. TCDD appeared to be less efficient than TPA as an inducer of PAI-2. In contrast to induction by TPA, PAI-2 induction by TCDD was found to be biphasic, with an early peak of mRNA at 1-3 h and a late peak at 12-24 h. A biphasic response was also seen at the protein level although production of PAI-2 protein lagged behind the corresponding mRNA. PAI-2 is known to contain AP-1 sites, i.e. Jun/Fos protein-binding sites, in its promotor region. Hence, PAI-2 induction by TCDD has originally been conceived to be due to an indirect response, secondary to the induction of Jun/Fos proteins. Therefore, expression of jun/fos genes and their AP-1 activity were studied at the early phase of PAI-2 induction by TCDD. TCDD did not increase mRNA of c-fos, c-jun, junB or junD (in contrast to TPA which markedly increased the expression of c-fos and junB), nor did TCDD increase AP-1 activity. In conclusion, the findings suggest that PAI-2 induction by TCDD is not restricted to human keratinocytes but includes liver cells and monocytic U937 cells. The induction mechanism is complex but the early phase does not appear to involve Jun/Fos proteins.
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PMID:TCDD-inducible plasminogen activator inhibitor type 2 (PAI-2) in human hepatocytes, HepG2 and monocytic U937 cells. 863 Nov 29

Although hepatocellular carcinoma (HCC) cells are more resistant to anoxic injury than normal hepatocytes, the mechanisms responsible for this differential sensitivity remain obscure. Because enhanced calpain protease activity contributes to hepatocyte necrosis, we tested the hypothesis that HCC cells resist anoxia by preventing calpain activation. Cell viability in two rat HCC cell lines (N1S1 and McA-RH7777 cells) was fourfold greater compared to rat hepatocytes after 4 h of anoxia. Although calpain activity increased twofold in rat hepatocytes during anoxia, no increase in calpain activity occurred in HCC cells. Western and Northern blot analysis revealed greater or equivalent expression of calpains and calpastatin in HCC cells compared to hepatocytes. Because increases in cytosolic free Ca++ (Cai++) and phospholipid degradation products regulate calpains in vitro, we measured Cai++ and phospholipid degradation. Ca++i did not change in any cell types during 60 min of anoxia. In contrast, phospholipid degradation was fourfold greater in hepatocytes compared to HCC cells. Melittin, a phospholipase A2 activator, increased calpain activity and cell necrosis in all cell types; melittin-induced cell necrosis was ameliorated by a calpain protease inhibitor. In summary, these data demonstrate for the first time 1) calpain activation without a measureable increase in Ca++i, 2) phospholipase-mediated calpain activation in hepatocytes and HCC cells, and 3) the adaptive mechanism responsible for the resistance of HCC cells to anoxia-an inhibition of phospholipid-mediated calpain activation. Interruption of phospholipase-mediated calpain activation may be a therapeutic strategy for preventing anoxic cell injury.
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PMID:Hepatocellular carcinoma cells resist necrosis during anoxia by preventing phospholipase-mediated calpain activation. 865 97

Clotting factor XII (Hageman factor) contains epidermal growth factor (EGF)-homologous domains and is reported to be a potent mitogen for human hepatoma (HepG2) cells. In this study, we tested whether factor XII exhibits growth factor activity on several other EGF-sensitive target cells, including fetal hepatocytes, endothelial cells, alveolar type II cells, and aortic smooth muscle cells. We found that factor XII significantly enhanced [3H]thymidine incorporation in aortic smooth muscle cells (SMCs) and all other cells tested. Tyrphostin, a growth factor receptor/tyrosine kinase antagonist, inhibited both EGF- and factor XII-induced responses. However, differences in the levels of magnitude of DNA synthesis, the observed synergism between EGF and factor XII, and the differential sensitivity to tyrphostin suggest that the EGF receptor and the factor XII receptor may be nonidentical. The factor XII-induced mitogenic response was achieved at concentrations that were 1/10th the physiologic range for the circulating factor and was reduced by popcorn inhibitor, a specific factor XII protease inhibitor. Treatment of aortic SMCs with factor XII, as well as activated factor XII, resulted in a rapid and transient activation of a mitogen-activated/extracellular signal-regulated protein kinase with peak activity/tyrosine phosphorylation observed at 5 to 10 min of exposure. Taken together, these data (i) confirm that clotting factor XII functions as a mitogenic growth factor and (ii) demonstrate that factor XII activates a signal transduction pathway, which includes a mitogen-activated protein kinase.
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PMID:Factor XII-induced mitogenesis is mediated via a distinct signal transduction pathway that activates a mitogen-activated protein kinase. 870 Sep 4


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