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)

A growth factor has been isolated from HTC-SR rat hepatoma tissue culture cells which specifically stimulates DNA synthesis and cell proliferation of the HTC cells that produce it. The factor can be isolated from HTC cell conditioned medium or from an HTC cell extract. This autocrine factor has been purified 640-fold from a postmicrosomal supernatant by successive steps, involving ethanol precipitation, heating at 80 degrees C for 10 min, chromatography on a DEAE Bio-Gel A column, and chromatography on a heparin-sepharose affinity column. The major peak of activity eluted from the heparin column migrates as a single band on SDS-PAGE with an apparent Mr of 60,000. The factor is resistant to acid, heat, and neuraminidase but sensitive to trypsin, papain, and protease. The autocrine nature of the factor is indicated by the finding that several other types of cells do not respond with increased DNA synthesis. Mouse L-cells, BHK cells, Novikoff hepatoma cells, hepatocytes in primary culture, and an epithelial-like rat liver-derived cell line (Clone 9) were tested, and none of the cells could be stimulated. Small amounts of the factor could be extracted from the Clone 9 cells, however. This material had the same physical and purification properties as the factor extracted from HTC cells, but it did not stimulate DNA synthesis in Clone 9 cells, only in HTC cells. Addition of the factor resulted in an almost immediate stimulation of DNA synthesis in a proliferating HTC cell population. When the factor was added together with [3H]thymidine for 2 h, a significant stimulation of DNA synthesis was observed, provided the addition was made between 18 and 48 h after the cells had been plated. Autoradiographic studies indicated that the factor both accelerates DNA synthesis in cells already making DNA and increases the number of cells entering the S period. The stimulation of DNA synthesis was completely inhibited by 10 mM hydroxyurea, whether the factor was present for 2, 24, or 48 h in the culture. A significant increase in cell number due to addition of the factor was also observed. This accelerated proliferation was detectable only after the cells had been in culture for at least 48 h with the factor present.
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PMID:Isolation of an autocrine growth factor from hepatoma HTC-SR cells. 358 47

The purification to homogeneity of hexokinases B and C from the cytosol of rat Novikoff hepatoma was achieved by a protocol using an initial chromatography on Blue 2-agarose to separate the isoenzymes from each other. After that step each hexokinase was subjected to chromatography on DEAE-cellulose, hydroxyapatite and Sephacryl S-300, followed by re-chromatography on hydroxyapatite. The final preparations of hexokinases B and C had specific activities of 86 and 23.5 units/mg of protein respectively, and gave single bands on electrophoresis under non-denaturing conditions or in SDS/polyacrylamide gels. Mr values of about 100,000 were found for both isoenzymes either by Sephacryl S-300 chromatography or by SDS/polyacrylamide-gel electrophoresis. Values of apparent Km for glucose and ATP of pure hexokinase B were similar to those reported for the enzyme from other sources. The apparent Km value for glucose of hexokinase C was 0.025 mM. Marked inhibition of hexokinase C by glucose concentrations above 0.2 mM was found. The effect was partially relieved by ATP concentrations above 1 mM and was independent of pH. Glucose 6-phosphate was inhibitory, but the Ki value (0.18 mM) is higher than those reported for other animal hexokinases. The amino acid composition of hexokinase C was found to be similar to those reported for hexokinases B and D. Also, an immune serum directed against hexokinase A was able, at low dilutions, to bind hexokinases B and C. An immune serum directed against hexokinase C was able, at low dilutions, to bind hexokinase B and also, but weakly, hexokinase A.
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PMID:Hexokinase isoenzymes from the Novikoff hepatoma. Purification, kinetic and structural characterization, with emphasis on hexokinase C. 359 83

The association of nucleolar phosphoprotein C23 with preribosomal ribonucleoprotein (RNP) particles was examined in Novikoff hepatoma nucleoli. RNA was labeled with [3H]uridine for various times in cell suspensions, and RNP particles were extracted from isolated nucleoli and fractionated by sucrose gradient ultracentrifugation. The majority of protein C23 cosedimented with fractions containing rapidly labeled RNA (RL fraction). To determine whether there was a direct association of RNA with protein C23, the RL fraction was exposed to ultraviolet (UV) light (254 nm) for short periods of time. After 2 min of exposure there was a 50% decrease in C23 as measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analyses, with no significant further decrease at longer times. When UV-treated fractions were subjected to phenol/chloroform extractions, as much as 30% of the labeled RNA was found in the phenol (protein) layer, indicating that RNA became cross-linked to protein. Similarly, there was an increase in protein C23 extracted into the water layer after irradiation. By SDS-PAGE analyses the cross-linked species migrated more slowly than protein C23, appearing as a smear detected either by [3H]uridine radioactivity or by anti-C23 antibody. With anti-C23 antibodies, up to 25% of the labeled RNA was precipitated from the RL fraction. Dot-blot hybridizations, using cloned rDNA fragments as probes, indicated that the RNA in the RL fraction and the immunoprecipitated RNA contained sequences from 18S and 28S ribosomal RNA.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Association of protein C23 with rapidly labeled nucleolar RNA. 379 May 20

When membrane fractions from mouse liver, Ehrlich ascites tumor and MH134 hepatoma were incubated with [gamma-32P]ATP at 0 degree C in the presence of MnCl2, ZnCl2 and NaVO3, proteins were phosphorylated on tyrosines to a larger extent in liver membranes than in tumor membranes. Separation of labelled proteins by SDS-gel electrophoresis showed phosphorylated alkali-resistant bands of 170, 140, 130, 80, 56, 53 and 46 kDa proteins in Ehrlich ascites tumor membranes; liver membranes exhibited more strongly phosphorylated bands of 170, 56, 53 and 46 kDa proteins. Epidermal growth factor stimulated the tyrosine phosphorylation of only a 170 kDa protein, which was more significant in liver membranes. Liver membranes exhibited slightly higher levels of tyrosine protein kinase activity compared to tumor membranes.
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PMID:Comparison of tyrosine phosphorylation of proteins by membrane fractions from mouse liver, Ehrlich ascites tumor and MH134 hepatoma. 387 13

By means of the reaction of specific inhibition of precipitation in agarose gel and using the rabbit immune sera against nuclear nonhistone proteins (NHP) in the NHP-DNA complexes isolated from the rat kidney it is shown that the single intraperitoneal injection of hepatocarcinogens, 4-dimethylaminoazobenzene (DAB) or N-nitrosodiethylamine (DEN) induces the appearance of hetero-organic antigens of the kidney nature in the NHP pattern of the liver. These antigens identical, as it proved to be, to the same NHP-antigens from the cells of transplantable rat hepatoma 27 and ascitic Zajdela hepatoma could be found in the NHP pattern of the rat liver during 1 to 12 and 1 to 64 days after the DAB and DEN injection, respectively. In all cases when the hetero-organic NHP-antigens were found the profiles of proper phosphoprotein kinase activity of the fractions of NHP eluted by 0.4-0.5 M NaCl using gradient chromatography on phosphocellulose contained peaks that were not characteristic to the liver NHP but were typical of NHP from the intact rat kidney. In the SDS-PAAG electrophoresis the mentioned fractions form one line with the molecular weight 15000-20000.
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PMID:[Detection of the common features in the antigenic structure and the spectra of the phosphoprotein kinase activity proper of the water-soluble fractions of DNA-free nuclear nonhistone proteins from hepatomas and the liver in rats following a single administration of hepatocarcinogens]. 393 50

The nuclear matrix of Zajdela hepatoma cells, in which DNA synthesis was blocked by novobiocin, contained 2.5-3.0 times more DNA and protein not dissociating in 2 M NaCl than the nuclear matrix of control cells. Chromatography of nuclear matrix preparations on Sepharose 2B-CL resulted in isolation of tightly bound DNA-protein complexes which did not dissociate in 8 M urea or 0.1% SDS. Subsequent elution of DNA-protein complexes on a hydroxylapatite column with a buffer containing 4 M guanidine hydrochloride and 5 M urea caused partial dissociation of the complexes. Electrophoretic analysis revealed essential changes in the composition of proteins DNA-protein complexes of hepatoma cells nuclear matrix during inhibition of DNA synthesis.
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PMID:[Reorganization of the protein composition of the nuclear matrix of hepatoma cells after inhibition of DNA synthesis with novobiocin]. 407 85

A new method to purify papain- or detergent-solubilized form (papain or detergent form) of gamma-glutamyltransferase from rat hepatomas as well as from rat kidney by immuno-affinity column chromatography is presented. The antibody-column was prepared by coupling the anti-kidney papain form antibody, which had been purified by using a kidney papain form-Sepharose column, to CNBr-activated Sepharose 4B. The enzyme bound to the antibody-column was eluted with 0.04 M NH4OH. By this method, detergent forms were purified 300 and 1600-fold in approx. 50% yields from rat kidney and rat ascites hepatoma AH 13, respectively, and the papain form was also purified 16 000-fold in a similar yield from primary hepatoma which has a very low activity of this enzyme. Preparations thus obtained apparently did not contain any peptide other than heavy and light subunit peptides of this enzyme on SDS-polyacrylamide gel electrophoresis. The detergent form of kidney enzyme was preferentially absorbed to a hydrophobic column of aminooctyl-Sepharose, while the papain form was not, suggesting that the detergent form might be adsorbed to the column through hydrophobic interaction of the membrane-binding domain. The domain peptide was also purified by the hydrophobic column after release from the detergent form by papain treatment. The molecular weight of the peptide was estimated to be about 16 000 on SDS-polyacrylamide gel electrophoresis. On double immunodiffusion, the domain peptide reacted with anti-detergent form antibody but not with anti-papain form antibody. The domain-specific antibody was also purified from the anti-detergent form antibody.
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PMID:Purification of detergent-solubilized form and membrane-binding domain of rat gamma-glutamyltransferase by immuno-affinity and hydrophobic chromatography. 613 98

Some regularities of [3H]triamcinolone acetonide (TA)binding to glucocorticoid-sensitive Morris hepatoma cell nuclei were studied. It was shown that part of the hormone incorporated into the nuclei form highly stable complexes with nuclear structures that are not destroyed during nuclei lysis with 0.25% SDS. Such complex formation is not practically suppressed by a 500-fold excess of non-labeled TA. As the time of incubation of Morris hepatoma cells with the hormone rises from 10 min to 24 hours, the specific binding of TA to the nuclei decreases, while the specific radioactivity of the [3H]TA-nuclei complexes resistant to 0.25% SDS increases. The stable complexes are eluted from Sepharose 6B together with the bulk of the nuclear proteins and do not contain DNA. Actinomycin D extrudes, to some extent, the [3H]TA from the complexes having specific binding sites that are localized in the nuclei and induces the accumulation of the steroid in the firmly bound nuclear complexes resistant to 0.25% SDS. The ability to suppress hormonal induction of tyrosine aminotransferase was detected only in the antibiotics with a high affinity for the GC-pairs of DNA. i.e., actinomycin D and mitramycin. It was assumed that high concentrations of TA specifically bound to the nuclei are necessary only at initial steps of hormonal induction. At later stages, gradual dissociation of the complexes takes place and the hormone is accumulation within the composition of the SDS-resistant firmly bound complexes.
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PMID:[Interaction of triamcinolone acetonide with Morris hepatoma cells in the presence antibiotics--inhibitors of RNA synthesis]. 615 1

Monoclonal antibodies were generated against the intermediate filament proteins of different human cells. The reactivity of these antibodies with the different classes of intermediate filament proteins was determined by indirect immunofluorescence on cultured cells, immunologic indentification on SDS polyacrylamide gels ("wester blot" experiments), and immunoperoxidase assays on intact tissues. The following four antibodies are described: (a) an antivimentin antibody generated against human fibroblast cytoskeleton; (b), (c) two antibodies that recognize a 54-kdalton protein in human hepatocellular carcinoma cells; and (d) an antikeratin antibody made to stratum corneum that recognizes proteins of molecular weight 66 kdaltons and 57 kdaltons. The antivimentin antibody reacts with vimentin (58 kdaltons), glial fibrillary acidic protein (GFAP), and keratins from stratum corneum, but does not recognize hepatoma intermediate filaments. In immunofluorescence assays, the antibody reacts with mesenchymal cells and cultured epithelial cells that express vimentin. This antibody decorates the media of blood vessels in tissue sections. One antihepatoma filament antibody reacts only with the 54 kdalton protein of these cells and, in immunofluorescence and immunoperoxidase assays, only recognizes epithelial cells. It reacts with almost all nonsquamous epithelium. The other antihepatoma filament antibody is much less selective, reacting with vimentin, GFAP, and keratin from stratum corneum. This antibody decorates intermediate filaments of both mesenchymal and epithelial cells. The antikeratin antibody recognizes 66-kdalton and 57-kdalton proteins in extracts of stratum corneum and also identifies proteins of similar molecular weights in all cells tested. However, by immunofluorescence, this antibody decorates only the intermediate filaments of epidermoid carcinoma cells. When assayed on tissue sections, the antibody reacts with squamous epithelium and some, but not all, nonsquamous epithelium. Therefore this antistratum corneum antibody and the anti-54-kdalton antibody identify unique epitopes present in the various cytokeratin molecules of epithelial cells. None of the hybridoma antibodies react with neurofilament proteins. The different patterns of reactivity of these antibodies suggest that many of the immunologically distinct intermediate filament proteins contain common antigenic determinants.
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PMID:Monoclonal antibodies to intermediate filament proteins of human cells: unique and cross-reacting antibodies. 618 72

Reuber H-35 hepatoma cells were examined for their ability to synthesize protein in vitro, especially to produce alpha-fetoprotein (AFP). The presence of AFP in the culture supernatant solution was determined immunologically by the micro-Ouchterlony method. Charge heterogeneity of AFP was examined electrophoretically in continuous gradient polyacrylamide microgels. With regard to the duration of culture, there was no remarkable change in the ratio of two peaks of AFP, and which came out as a major combined peak and a similar peak by PAS staining on the condition of added SDS. These findings indicated that Reuber H-35 hepatoma cells had potential to produce two charge variants of AFP in vitro.
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PMID:Characterization of alpha-fetoprotein secreted from cultured reuber H-35 hepatoma cells. 618 63


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