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)

1. A serine protease of hepatoma 8999, isolated in the mitochondrial fraction, was purified and crystallized. The purified enzyme was apparently homogeneous on ultracentrifugal analysis and polyacrylamide disc gel electrophoresis. The ratio of absorbance at 280 nm and 260 nm, A280/A260, was 1.90 and its absorption coefficient, A280 1% was 10.5 cm-1 estimated from dry weight measurements. Its S20, w value was 2.23 S and its molecular weight was estimated to be 24000 +/- 1000. The enzyme contained twice as much lysine, arginine and histidine as chymotrypsinogen did, but had a very similar amino acid composition to serine protease from skeletal muscle. Its isoelectric point was pH 10.6. 2. The substrate specificity of the enzyme was the same as that of chymotrypsin A. Its Km and kcat values for N-acetyl-L-tyrosine ethyl ester, N-acetyl-L-phenylalanine ethyl ester and N-acetyl-L-tryptophan ethyl ester were 0.35 mM and 10.69 s-1, 0.38 mM and 10.7 s-1, and 0.11 mM and 11.8 s-1, respectively. Its activity was completely inhibited by phenylmethylsulfonyl fluoride and partially inhibited with tosylphenylalanine chloromethyl ketone. 3. The enzyme was shown to be located in different granules from the intracellular particules (light and heavy mitochondrial fraction) by sucrose density gradient centrifugation, and it was stained in mast cells of the hepatoma 8999 by the immunofluorescent technique. 4. Serine protease is present in different amounts in various organs of rat and the enzyme from hepatoma 8999 gave a single band that fused completely with those of the enzymes from skeletal muscle, heart, liver and kidney, respectively, on Ouchterlony double-diffusion analysis using antiserum to the crystalline enzyme of hepatoma 8999, but the enzyme from small intestine did not react with the antiserum.
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PMID:Purification, characterization and localization of serine protease of Morris hepatoma 8999. 11 11

Quiescent, contact inhibited H-35 rat hepatoma cell cultures maintained in minimal essential medium contain a very low level of ornithine decarboxylase activity. However, 2 h after the addition of 10% fetal calf serum to the culture medium, the enzyme activity increases by approx. 100-fold. This increase can be completely inhibited by the simultaneous addition of 10(-2) M putrescine. The presence of putrescine elicits the appearance of an intracellular inhibitor of ornithine decarboxylase. This inhibitor of ornithine decarboxylase has a molecular weight of 26500, is sensitive to the action of chymotrypsin and is noncompetitive with respect to ornithine. The intracellular appearance of this inhibitor is sensitive to cycloheximide but is only partially inhibited by actinomycin D.
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PMID:The appearance of an ornithine decarboxylase inhibitory protein upon the addition of putrescine to cell cultures. 17 75

A pancreatic carcinoma and liver metastases associated with marked elevation of the serum alpha-fetoprotein (AFP) level were resected from a 57-year-old man. On microscopic examination, the tumor cells showed a predominantly acinar arrangement, with tubular and trabecular structures; in some foci it had features of a medullary pattern. Alpha-fetoprotein, lipase, trypsin, chymotrypsin, and alpha 1-antitrypsin were strongly demonstrated in tumor tissue by immunohistochemical techniques. A biochemical analysis of AFP on affinity sepharose columns revealed that the AFP derived from the tumor tissues was similar to that of hepatocellular carcinoma. Ultrastructural study showed that most of the tumor cells had abundant rough endoplastic reticulum and numerous zymogen granules. No squamoid corpuscles, neuroendocrine granules, bile production, or bile canaliculi were recognized. These findings suggest that this unique tumor originated from acinar cells.
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PMID:Alpha-fetoprotein-producing acinar cell carcinoma of the pancreas. 137 64

During the formation of an inhibitory complex with neutrophil elastase, alpha 1 antitrypsin (alpha 1 AT) undergoes a structural rearrangement and the resulting alpha 1 AT-elastase complex becomes endowed with chemoattractant activities, mediates an increase in synthesis of alpha 1 AT, and is rapidly cleared from the circulation. In previous studies we have provided evidence that these biological activities involve the recognition of a conformation-specific domain in the alpha 1 AT molecule by a cell surface receptor on human hepatoma HepG2 cells and human monocytes. The receptor has been termed the serpin-enzyme complex (SEC) receptor because it also recognizes complex of serpins antithrombin III, alpha 1 anti-chymotrypsin, and C1 inhibitor with their cognate enzymes. Because a pentapeptide domain of alpha 1 AT (amino acids 370-374, Phe-Val-Phe-Leu-Met) is sufficient for binding to the SEC receptor and the sequence of this domain is remarkably similar to those of substance P, several other tachykinins, bombesin, and the amyloid-beta peptide, we have examined the possibility that these other ligands bind to the SEC receptor. The results indicate that substance P, several other tachykinins, and bombesin compete for binding to, and cross-linking of, the SEC receptor. The SEC receptor is distinct from the substance P receptor by several criteria. There is no substance P receptor mRNA in HepG2 cells; the SEC receptor is present in much higher density on receptor-bearing cells and binds its ligands at lower affinity than the substance P receptor; the SEC receptor is much less restricted in the specificity with which it recognizes ligand; ligands for the SEC receptor including peptide 105Y (based on alpha 1 AT sequence 359-374), alpha 1 AT-protease complexes, and bombesin do not compete for binding of substance P to a stable transfected cell line expressing the substance P receptor. Finally, we show here that the amyloid-beta peptide competes for binding to the SEC receptor but does not bind to the substance P receptor, therein raising the possibility that the SEC receptor is involved in certain biological activities, including the recently described neurotrophic and neurotoxic effects ascribed to the amyloid-beta peptide.
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PMID:Amyloid-beta peptide, substance P, and bombesin bind to the serpin-enzyme complex receptor. 171 86

We provide evidence that both covalent and non-covalent inhibitors of chymotrypsin-like activities inhibit the insulin-induced DNA replication, while the hormonal metabolic effects such as induction of tyrosine aminotransferase activity or increase of amino-acid transport remain unchanged. Besides, the protease inhibitors that we tested were without any effect on both the autocatalytic phosphorylation of insulin receptors and the tyrosine kinase activity towards poly(glutamate/tyrosine). The inhibitory effect of protease inhibitors on DNA synthesis was also visible when fibroblast growth factor (FGF) was used to commit cells in the proliferative cycle. This observation proves that the involvement of a putative protease is not restricted to the insulin mitogenic pathway. Finally, we observed that Fao cells totally escaped the inhibitory action of a covalent inhibitor of chymotrypsin after having been exposed to insulin for 10 h. We propose that a chymotrypsin-like activity is involved in the intracellular signalling leading to the proliferation of rat hepatoma cells up to a non-return point situated in the middle of G1 (6-8 h).
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PMID:Inhibitors of chymotrypsin-like activities selectively block the mitotic pathway in rat hepatoma cells. 198 14

Phosphorylation of glucocorticoid receptors is increased by hormone binding and has been implicated in transcriptional regulation. We performed a phosphoamino acid analysis and identified the phosphorylated regions of the glucocorticoid receptor with respect to its functional domains before and after hormone activation. Receptor was isolated by immunoprecipitation from [32P]orthophosphate-labeled FTO 2B rat hepatoma cells grown in the absence or presence of glucocorticoids. The receptor contained mainly phosphoserine, with little phosphothreonine and no phosphotyrosine. Partial proteolysis of receptor from hormone-treated or control cells revealed a similar phosphopeptide pattern. Chemical cleavage with hydroxylamine and cyanogen bromide or digestion with trypsin and chymotrypsin localized the majority of receptor phosphorylation sites to a transactivation domain amino-terminal of the DNA-binding domain. Phosphorylation of this region, termed tau 1/enh2, was increased 2-3-fold by hormone treatment. The DNA-binding domain itself is weakly phosphorylated; no phosphorylation was found in the hormone-binding domain. Phosphorylated regions were also identified in receptor deletion mutants stably transfected into CV-1 monkey kidney cells. Hormone-independent phosphorylation was observed with a strong constitutively active mutant lacking the hormone-binding domain. No phosphorylation was detected in a mutant lacking the amino-terminal region, which showed only weak, hormone-dependent activity. These results support the idea that phosphorylation is important for the strength of the glucocorticoid receptor as a transcriptional regulator.
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PMID:Hormone-dependent phosphorylation of the glucocorticoid receptor occurs mainly in the amino-terminal transactivation domain. 210 36

Hepatocellular carcinoma with osteoclast-like giant cells (hepatic giant cell carcinoma [HGCC]) is a rare entity, with only three cases reported. The tumor is histologically similar to giant cell tumor (GCT) of bone, and the origin of the multinucleated giant cells and mononuclear stromal cells has not been determined. The purpose of this report is to present a case of this rare tumor and compare its ultrastructural and immunohistochemical features with those of a conventional GCT of bone. Histologically, the HGCC consists of sheets of osteoclast-like giant cells with a background of mononuclear cells. The giant cells lack the pleomorphism seen in hepatocellular carcinomas with anaplastic giant cells. At the light microscopic level, most of this tumor was nearly identical to a GCT of bone, but several microscopic fields (less than 5% of the tumor) had the histologic appearance of a "usual" hepatocellular carcinoma. The hepatic tumor was negative for HAM 56, epithelial cytokeratins, muramidase, and alpha-1-antitrypsin, with only focal positivity for chymotrypsin in mononuclear and giant cells. The GCT was strongly positive for alpha-1-antitrypsin and chymotrypsin in both the mononuclear and giant cells and showed focal, weak staining for AE1 and AE3 in the mononuclear stromal cells. Ultrastructurally, both mononuclear and giant cells of the HGCC showed features typical of hepatocellular carcinoma. Although the patient presented in this report died, the pattern of growth was different from most hepatocellular carcinomas. The overall histologic features of this tumor are distinctive and appear to justify separating this variant from other types of hepatocellular carcinoma.
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PMID:Hepatic giant cell carcinoma. An ultrastructural and immunohistochemical study. 215 1

The nuclear Ah receptor from mouse hepatoma (Hepa-1c1c9) cells is a 176-kDa multimeric protein which is stable under conditions of up to 1 M KCl. Under denaturing conditions, the Hepa-1 nuclear receptor can be dissociated into a ligand-binding subunit of Mr approximately 91,000. The identity of subunits that compose the nuclear Ah receptor is currently unknown. We used partial proteolysis under nondenaturing conditions as an approach to study the domain organization of the nuclear form of Ah receptor from Hepa-1c1c9 cells treated with [3H]2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in culture. Low concentrations of trypsin (0.5 microgram/mg nuclear protein) generated heterogeneous fragments with the main fragment having a Stokes radius (Rs) approximately 6 nm. More discrete ligand-binding fragments of Mr approximately 84,000 (Rs approximately 4 nm/approximately 5 S) and Mr approximately 16,000 (Rs approximately 2 nm/approximately 2 S) could be generated using higher concentrations of trypsin (5 micrograms/mg nuclear protein). The relative concentration of the 84 and 16-kDa fragment was dependent on duration of protease treatment; formation of the 16-kDa fragment was accompanied by some loss in [3H]TCDD binding. Treatment of nuclear Ah receptor with alpha-chymotrypsin (1 microgram/mg nuclear protein) generated a single, apparently homogeneous ligand-binding fragment of Mr approximately 101,000 (Rs approximately 5 nm/approximately 5 S). When analyzed by DNA-cellulose chromatography, the chymotryptic fragment eluted at a significantly higher KCl concentration (462 mM) compared to native untreated nuclear Ah receptor (385 mM). Despite this increased affinity for DNA-cellulose columns, the ligand-binding fragment generated by chymotrypsin treatment was unable to interact with a dioxin responsive element in a gel retardation assay. DNA-cellulose binding ability, therefore, does not appear to be a reliable indicator of specific DNA interactions for these protease-modified fragments.
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PMID:Nuclear Ah receptor from mouse hepatoma cells: effect of partial proteolysis on relative molecular mass and DNA-binding properties. 217 30

A human hepatoma cell line, associated with thorotrast exposure, from an hepatitis B marker-negative patient was established as a permanent cell line (Mz-Hep-1) in tissue culture. Histology of the primary tumor, as well as phase contrast, transmission and scanning electron microscopy of the cultured cells showed typical characteristics of liver cells. Mz-Hep-1 cells secreted complement components (C2, C3, C4), carcinoembryonic antigen, lactate dehydrogenase, chymotrypsin, haptoglobin and retinol-binding protein and expressed HLA-, transferrin-, blood group B-related determinants and complement component C5 and carcinoembryonic antigen on their cell surface. Mz-Hep-1 cells represent the first human hepatoma cell line, which is strongly associated with a carcinogen.
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PMID:Hepatocellular carcinoma after thorotrast exposure: establishment of a new cell line (Mz-Hep-1). 241 35

We have isolated three cDNA clones for human alpha 2-plasmin inhibitor (alpha 2-PI). Two clones are from human hepatoma cell line, Hep G2, and cover the entire protein coding region plus the 3'-flanking region up to the poly(A) sequence, and the other clone is from human liver and contains the carboxyl-terminal half. The total length of the cDNAs is 2.29 kb, corresponding to more than 95% of the full-length mRNA. alpha 2-PI seems to consist of 452 amino acid residues plus 39 amino acid residues for the signal peptide. The amino acid sequence shows 23 to 28% homology to those of five other protease inhibitors, plasminogen activator inhibitor (PAI), protein C inhibitor (PCI), alpha 1-antitrypsin (alpha 1-AT), antithrombin III (AT III), and alpha 1-antichymotrypsin (alpha 1-AC). alpha 2-PI seems to be the most distantly related among these inhibitors. Comparison of the phylogenetic trees of proteases and their inhibitors indicates that four proteases, namely elastase (or trypsin), chymotrypsin, plasminogen activator, and thrombin, may have evolved concurrently with the corresponding inhibitors. However, alpha 2-PI and PCI seem to have evolved asynchronously from their substrates. The data suggest that alpha 2-PI may originally have inhibited some protease other than plasmin, and protein C may have had an inhibitor different from the present one early in its evolutionary history.
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PMID:Structure of human alpha 2-plasmin inhibitor deduced from the cDNA sequence. 283 Feb 48


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