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 rat hepatoma cell line, H4-II-E, was grown serially over a 1-year period and about 30 passages in arginine-, glutamine-, and tyrosine-deprived and ornithine-supplemented Eagle's minimum essential medium with no supplements other than biotin. The adapted cell line, R-Y121B, proliferates in the above mentioned medium with a doubling time of about 4 days and maintains hepatic "marker" enzymes such as tyrosine aminotransferase, phenylalanine hydroxylase, and all the enzymes of the urea cycle.
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PMID:Continuous culture of Reuber hepatoma cells in serum-free arginine-, glutamine- and tyrosine-deprived chemically defined medium. 610 14

gamma-Glutamyltransferase was solubilized from human hepatoma tissues by bromelain treatment, and some of its properties were compared with those of the normal adult liver enzyme. An electrophoretic study showed a slightly different mobility between the two enzymes before and after neuraminidase treatment. The hepatoma tissue enzyme was distinguished from the normal liver enzyme by decreased affinity to Con A. However, the enzymes from the two sources were found to be very similar or identical with respect to molecular weight, Michaelis constant, pH optimum, thermostability, effect of various L-amino acids as acceptors, behavior to divalent cations or ethylenediaminetetraacetate, inhibition by urea or sodium dodecyl sulfate, and immunological properties. These results suggest that the hepatoma tissue gamma-glutamyltransferase is largely due to altered glycosylation of this glycoprotein in hepatoma cells.
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PMID:gamma-Glutamyltransferase from human hepatoma tissue in comparison with normal liver enzyme. 611 82

Cell-specific chromatin antigens have been detected in rat Sertoli cells. Antisera were raised in rabbits to dehistonized chromatin prepared from 5- to 6-day cultures of rat Sertoli cells and immunoreactivity was assessed with microcomplement fixation tests or immunoidentification of antigens separated electrophoretically and transferred to nitrocellulose sheets. Tissue specificity was confirmed further by immunoabsorption. These antisera recognized only components of Sertoli cell chromatin; chromatins prepared from rat liver, kidney, thymus, Novikoff hepatoma, a testes germinal cell fraction, or purified rat DNA showed little or no immunoreactivity. Nitrocellulose transfers of total chromosomal proteins revealed the presence of two high-molecular-weight antigens (greater than 200,000) and a broad range of weaker immunologic species (M tau about 50,000-200,000) in Sertoli cell chromatin but not liver or thymus chromatin. Deproteinization of Sertoli cell chromatin with concentrated salt and urea at pH 6 or 8 produced an increase in complement-fixing activity of the fraction sedimenting with DNA and micrococcal nuclease digestion studies showed these fractions to depend in part on DNA for antigenicity. Individual antigens in the protein-DNA pellets of pH 8 salt and urea fractionated chromatin could not be identified with antigens on nitrocellulose sheets. Collectively, these observations suggest that at least two groups of cell-specific antigens exist in Sertoli cell chromatin; one group is detected after electrophoretic separation and transfer to nitrocellulose and the other group, reactive in complement fixation, cannot be detected through this method, apparently becoming antigenically inactive once the complex of protein and DNA is dissociated.
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PMID:Tissue and cell-specific antigens in chromatin from cultured rat Sertoli cells. 618 1

Cytoskeletal residues obtained after extraction of rat liver and cultured rat hepatoma cells (line MH1C1) were used to isolate cytokeratin subunit complexes by solubilization in low salt buffer containing 4 M-urea. Alternatively, the complexes were prepared by solubilization of total cytoskeletal proteins in 9.5 M-urea or 6 M-guanidinium hydrochloride (Gu . HCl), followed by separation using reversed phase high pressure liquid chromatography and dialysis first against either 9.5 M-urea or 6 M-Gu . HCl and then against buffers containing either 4 M-urea or 2 M-Gu . HCl, respectively. The complexes contained only two cytokeratin polypeptides in a 1 : 1 ratio as demonstrated by electrophoresis and isoelectric focusing, i.e. components A (Mr 55,000; isoelectric point in 9.5 M-urea, pH 6.4) and D (Mr 49,000; isoelectric point, pH 5.38) which were separated from each other at urea concentrations higher than 7 M. The complex had a sedimentation coefficient S25,w of 4.96 S in 2 M-Gu . HCl. Sedimentation equilibrium analysis gave an average Mr value of 207,000 which was interpreted as a tetramer containing two chains each of A and D. This complex was also directly demonstrated by gel electrophoresis under non-dissociating conditions. Using dimethyl suberimidate to cross-link the complex in solution of 4 M-urea or 2 M-Gu . HCl, we identified covalently linked heterodimers of A and D, and a tetrameric unit containing equal amounts of A and D which was the largest cross-link product obtained. This complex was similar to the tetrameric complex of rat and human vimentin formed under the same conditions. The constituents of the cross-linked products were identified by two-dimensional ("diagonal") gel electrophoresis, involving the cleavage of the bis(amidine) cross-links after the initial separation in the first dimension. Identical cross-link products were recognized when cytokeratin filaments were used. By electron microscopy the complexes appeared as threads of 2 to 3 nm diameter with a mean length of approximately 48 nm. On dialysis to low salt buffer, the complexes formed 2 to 3 nm protofilaments, intertwisted 3 to 4 nm protofilaments and typical 7 to 11 nm intermediate-sized filaments. Complexes formed from equivalent cytokeratins of other species such as man and cow, as well as heterologous recombinations such as human component A mixed with bovine component D and vice versa, showed the same characteristics.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Heterotypic tetramer (A2D2) complexes of non-epidermal keratins isolated from cytoskeletons of rat hepatocytes and hepatoma cells. 620 69

U3 RNA, a capped small nuclear RNA found thus far only in the nucleolus, has been implicated in the processing and/or transport of preribosomal RNA [Busch, H., Reddy, R., Rothblum, L., & Choi, Y. C. (1982) Annu. Rev. Biochem. 51, 617-654]. Tris(hydroxymethyl)aminomethane (Tris) (10 mM, pH 7.0) extracts of Novikoff hepatoma nucleoli, which contained about 80% of total nucleolar U3 RNA, were analyzed by sucrose density gradient centrifugation. Approximately 65% of the U3 RNA was bound to greater than 60S preribosomal ribonucleoprotein (RNP) particles, and about 15% sedimented at less than 20 S. The association between the 65% of U3 RNA that was bound to the preribosomal RNP particles was stable up to 55 degrees C. About 10% of U3 RNA was base paired to preribosomal RNA after deproteinization at 22 degrees C. The base-paired fraction of U3 RNA was released from the preribosomal RNA by heating to 45 degrees C or treating with 4 M urea. These results show that of the total nucleolar U3 RNP, (a) about 55% is bound to preribosomal RNP particles primarily by protein interactions, (b) about 10% is base paired to preribosomal RNA, (c) approximately 15% sedimented slowly and consisted presumably of free U3 RNP particles, and (d) the remaining 20% of U3 RNP was not extractable using 10 mM Tris buffer. On the basis of the different association states of U3 RNP particles, a model is proposed for the binding and dissociation events which take place between U3 RNP and preribosomal RNP particles.
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PMID:Multiple states of U3 RNA in Novikoff hepatoma nucleoli. 621 Jan 4

1. The iron contents, gel migration rates and isoelectric-focusing patterns of normal liver and hepatocellular carcinoma ferritins from the same patients were compared. 2. Sucrose-density-gradient centrifugation showed that the number of iron atoms per ferritin molecule was decreased to approximately half in carcinoma tissue when compared with normal liver. 3. On electrophoresis, hepatocellular carcinoma ferritin migrates faster and is therefore more negatively charged than normal liver ferritin, thus refuting the general view that the more negatively charged a ferritin molecule the greater its iron content. 4. Comparison of tumour and normal liver ferritin subunit compositions on acid/urea/polyacrylamide gels showed hepatocellular carcinoma ferritin to contain an additional, more negatively charged, subunit to normal liver ferritin. 5. Isoelectric focusing showed that hepatocellular carcinoma tissue contains isoferritins with isoelectric points intermediate between the ranges of normal liver and normal heart isoferritins.
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PMID:A biochemical comparison of normal human liver and hepatocellular carcinoma ferritins. 624 28

The levels of the five enzymes of the urea cycle were measured in normal 5-week-old rats, in a transplantable hepatoma, and in the livers of tumor-bearing rats (host livers). The levels of all five enzymes were much lower in the hepatoma, although there was no exact correlation of the decrease in levels. In host livers, the levels were higher than in the tumors, but lower than in normal liver. The levels of all five urea cycle enzymes were positively correlated with dietary protein content in normal livers, in hepatomas, and in host livers. In fact, the hepatomas showed the greatest changes in response to diet. On all diets, the levels in host liver remained below those in normal liver, indicating that the decreased level was probably not due to preferential utilization of nutrients by the tumor. The levels of urea cycle enzymes in normal liver were not altered by a single injection of glucocorticoid, glucagon, or dibutyryl cyclic adenosine 3':5'-monophosphate. By contrast, in hepatoma, the levels were usually significantly elevated by the same treatment. In addition, the levels in host livers were always significantly elevated and were usually above those in normal animals, whether the latter were hormone treated or not. Injection of plasma from tumor-bearing rats into normal animals produced a decrease in the levels of all five enzymes; if glucagon was injected together with the plasma, large increases in levels were observed. This result supports the concept of a humoral factor produced by the tumor which affects the levels and the inducibility of urea cycle enzymes in host livers. Autopsied human primary hepatomas also showed levels of urea cycle enzymes below those in normal livers with host livers having intermediate values. A cell line derived from a human hepatoma showed induction of arginase by glucocorticoid in culture; in this, it resembled a cell line of the rat hepatoma. Tyrosine aminotransferase in human hepatoma cells was not induced by glucocorticoid; in this, it differed from the rat hepatoma cells where induction of this enzyme was observed.
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PMID:Regulation of urea cycle enzymes in transplantable hepatomas and in the livers of tumor-bearing rats and humans. 626 64

The phosphorylation of electrophoretically homogeneous preparations of the five major subcomponents of that thymus H1 histone by growth-associated histone kinase isolated from Ehrlich ascites tumor or Novikoff hepatoma cell chromatin results in the introduction of three to six phosphates/molecule into different subcomponents. Fully phosphorylated preparations of subcomponents 1 through 4 consist of H1 molecules containing a uniform number of phosphate groups, and run as single bands in long acid-urea gels. Fully phosphorylated preparations of subcomponent 5 consist of a mixture of molecules containing five and six phosphate groups. Phosphorylation of subcomponents 2, 4, and 5 occurs in both the NH2- and carboxyl-terminal regions of the molecules. Phosphorylation of subcomponents 1 and 3 occurs only in the carboxyl-terminal region. The central globular region of the histones is not phosphorylated. The major sites of phosphorylation in rat H1 histone subcomponents are similar to, but not entirely identical with, the major sites of phosphorylation previously characterized in total calf thymus H1, as determined by comparison of phosphopeptide maps. Highly phosphorylated rat H1 molecules, similar in phosphate content to those found in mitotic cells, have distinct chromatographic properties, compared to lightly phosphorylated molecules of the type found in interphase cells. This change in chromatographic properties appears to depend on the number of phosphate groups present in the histone rather than on the presence of phosphate in any specific sites.
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PMID:Characterization of highly phosphorylated subcomponents of rat thymus H1 histone. 629 83

Two groups of nonhistone chromatin proteins tightly bound to DNA were isolated from hamster liver and Kirkman-Robbins hepatoma with the use of hydroxyapatite columns: 1. NP proteins which can be briefly defined as nonhistone chromatin proteins, nondissociable from DNA in 5 M urea, and 2. a group of proteins nondissociable in 2 M KCl and thus believed to be nonelectrostatically bound to DNA. The proteins were characterized by their amino acid analysis, SDS-polyacrylamide gel electrophoresis and their influence on template activity of DNA. Some differences in electrophoretic patterns and template activity inhibition were found between the latter group of proteins from liver and hepatoma.
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PMID:Tightly complexed with DNA nonhistone chromatin proteins from hamster Kirkman-Robbins hepatoma. 630 91

The addition of the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA) to serum-starved quiescent Reuber H35 hepatoma cells results in a rapid 5- to 11-fold increase in the incorporation of 32Pi into a Mr = 32,000 ribosomal protein. The Mr = 32,000 protein was the major phosphorylated protein extracted from isolated 80 S ribosomes and was identified as the 40 S ribosomal protein S6 based upon its migration in two-dimensional gels. Insulin, which has been demonstrated to increase the phosphorylation of S6 in a number of cell lines, caused a 10- to 20-fold increase in the incorporation of 32Pi into this Mr = 32,000 ribosomal protein. S6 phosphorylation was dose- and time-dependent being detected as early as 5 min following the addition of 1.6 microM TPA. Maximal phosphorylation of ribosomal protein S6 was achieved by 60 min and remained elevated for at least 90 min in the presence of TPA. The 50% effective dose for TPA was estimated to be 0.14 microM. Based upon the altered migration of S6 in pH 8.5 urea-polyacrylamide gels, it was demonstrated that the increased 32Pi labeling of S6 by TPA was due to a net increase in the incorporation of phosphates into the S6 molecule. Non-tumor-promoting phorbol esters were ineffective in increasing the phosphorylation of S6. In whole cells, exogenously added 1 mM 8-bromoadenosine 3':5'-monophosphate failed to substantially increase phosphorylation of S6 suggesting that the TPA-induced phosphorylation of S6 occurs via a cyclic AMP-independent mechanism. The S6 amino acid residue phosphorylated in response to TPA was phosphoserine. A possible role for protein kinase C in the phosphorylation of ribosomal protein S6 is discussed.
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PMID:Tumor-promoting phorbol esters stimulate the phosphorylation of ribosomal protein S6 in quiescent Reuber H35 hepatoma cells. 631 90


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