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 antitumor activity of partially purified rabbit tumor necrosis factor (TNF) in combination with lentinan or chemotherapeutic agents was tested. Partially purified TNF was obtained from TNF-containing rabbit sera by salt precipitation and ion-exchange chromatography. Its specific activity, determined in vitro as its cytotoxic activity against L929 cells in the presence of actinomycin D, was 10(5) U/mg protein or about 30-fold that of the crude rabbit sera. The growths of MH134 hepatoma in C3H/He mice and Lewis lung carcinoma in C57BL/6 mice were partially inhibited by intratumoral administration of a suboptimal dose of the TNF preparation. Additional treatment with lentinan, actinomycin D, mitomycin C or adriamycin significantly increased the antitumor activity. In particular, combination therapy with TNF and lentinan was very effective against MH134 hepatoma without having detectable side-effects, showing that lentinan expanded the therapeutical potential of TNF. These results are discussed in relation to our previous results on combination antitumor therapy.
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PMID:Combination antitumor therapy with rabbit tumor necrosis factor and chemo- and immuno-therapeutic agents against murine tumors. 392 60

Biochemical and morphological studies were performed on Novikoff hepatoma ascites cell nucleolar matrix fractions prepared by deoxyribonuclease I digestion and high-molarity salt extractions essentially according to a published method [Berezney, R., & Buchholz, L. A. (1981) Exp. Cell Res. 20, 4995-5002]. The nucleolar matrix fraction was enriched in polypeptides of molecular mass of 28, 37.5, 40, 70, 72, 110 (protein C23), and 160 kDa, compared to the nuclear fraction in which polypeptides of molecular mass of 31, 33.5, 43.5, 46, 50, 56, and 59 kDa were predominant. About one-fourth of the protein, half of the RNA, and less than 4% of the DNA originally present in the nucleoli remained in the matrix fraction. Addition of single agents such as ethylenediaminetetraacetic acid, ribonuclease A, or mercaptoethanol during preparation had no significant effect on the polypeptide composition of the nucleolar matrix fraction. However, the combination of mercaptoethanol and ribonuclease A caused most of the RNA and protein to be removed, including protein C23 and the 160-kDa polypeptide, with polypeptides in the range of Mr 30 000-50 000 remaining. Electron microscopy of nucleolar matrix fractions revealed the presence of particles similar in size to the granular elements of nucleoli. However, when ribonuclease A and mercaptoethanol were included in the procedure, only amorphous material remained. Many proteins of nucleolar preribosomal RNP particles were also associated with the nucleolar matrix fraction. RNA from the nucleolar matrix fraction was enriched in sequences from 18S and 28S ribosomal RNA. These results indicate that preribosomal RNP particles are major constituents of a nucleolar matrix fraction prepared by the deoxyribonuclease I-high-molarity salt method.
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PMID:Preribosomal ribonucleoprotein particles are a major component of a nucleolar matrix fraction. 395 8

The in vivo cross-linking of proteins to DNA in intact Novikoff ascites hepatoma cells exposed to the chromium salt K2CrO4 was studied. DNA-protein complexes were assayed by high speed centrifugation of cells solubilized in buffered 4% sodium dodecyl sulfate and by electrophoretic identification of proteins associated with DNA-containing pellets. Further evidence of DNA-protein complexes, not dissociable in this buffer, was obtained by CsCl gradient centrifugation. Time dependence experiments showed that detectable cross-linking occurred after cells were exposed to chromium salt for at least 4 h, and the amount of DNA-protein complexes increased with longer incubation times. Complex formation occurred only with chromium salt concentrations of 200 microM or greater, and maximal cross-linking was effected at 5 mM. Immunotransfer methodology employing antibodies to nuclear matrix fraction and lamins was used to identify some of the polypeptides comprising the cross-linked complexes. These studies indicated specificity of chromium-induced complex formation within the nuclear protein fractions assayed. Our results document the ability of chromate to produce specific DNA-protein cross-links in living cells.
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PMID:Chromium-induced cross-linking of nuclear proteins and DNA. 399 61

Three classes of non-histone proteins were obtained from hamster Kirkman-Robbins hepatoma and liver nuclei following separation of nucleic acids with the polyethylene glycol-dextran mixture and fractionation of nuclear proteins on hydroxylapatite in a salt-glycerol-phenylmethylsulphonyl fluoride system at increasing concentrations of Na+ and K+ phosphate buffer, pH 6.8. Two-dimensional polyacrylamide gel electrophoresis of these proteins documented their high heterogeneity; many spots were common but some spots specific only for neoplastic or normal tissue were also observed.
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PMID:Comparison of non-histone proteins from hamster Kirkman-Robbins hepatoma and liver. 403 52

Cultured rat hepatoma cells (HTC-cells) were used to study the uptake of copper and zinc from a minimal salt-glucose medium, supplemented with albumin from different species or with ovalbumin. Competitive equilibrium dialysis showed that at low molar ratios of metal/protein (less than 1) the affinity for copper of human and bovine albumin was about equal, but that of dog albumin or ovalbumin was much lower. Only a small difference in affinity for zinc could be detected between human albumin and ovalbumin. Supplementing the medium with the different proteins the rate of copper uptake in the cell at a given molar Cu/protein ratio increased as follows: human albumin congruent to bovine albumin less than dog albumin less than ovalbumin. When the molar Cu/protein ratio was increased, a discontinuity was seen with all three albumin species at a ratio of about 1. In contrast, the zinc uptake mimics that of Cu/ovalbumin, and no discontinuity was observed using different molar Zn/protein ratios. These results indicate that the rate of copper and zinc uptake depends strongly on its affinity for the protein: a low affinity leads to a high uptake. The results suggest further that at physiologic concentrations zinc is taken up by a mechanism different from that for copper.
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PMID:Trace element uptake in liver cells. 2. Effect of different proteins in the medium on the uptake of copper and zinc by hepatoma cells. 404 49

-A comparison of the elution profiles of 18 aminoacyl-tRNA's from Novikoff hepatoma with those from normal liver on a methylated albuminkieselguhr column revealed the occurrence of new species of tRNA for histidine, tyrosine, and asparagine in the hepatoma. In addition, the hepatoma tRNA's for arginine, isoleucine, lysine, methionine, serine, alanine, and tryptophan eluted at a higher salt concentration than the corresponding tRNA's of normal liver. The remaining eight amino acids did not show any significant differences in the elution profiles.
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PMID:Differences in the transfer RNA's of normal liver and Novikoff hepatoma. 430 99

The nature of the association of U1 RNA with rapidly sedimenting RNP structures in rat hepatoma nuclei was investigated. The effects of salt and proteinase K treatment on the stability of this 'bound' form of U1 RNA were studied using sucrose density gradient analyses. Quantitation of the amount of U1 RNA remaining associated with large structures after treatment was used to assess the relative contribution of protein-protein (and protein-RNA) versus RNA-RNA interactions. Forty-eight percent of the total nuclear U1 RNA released by sonication was found in a 'bound' form when the sonicate was centrifuged through gradients containing 50 mM NaCl. Fifty percent of this 'bound' U1 RNA remained associated with rapidly sedimenting RNPs when the NaCl concentration was raised to 500 mM. To assess the contribution of protein independent interactions, large RNPs were completely deproteinized and their RNA moieties were then recentrifuged on gradients. By this analysis, 27% of the U1 RNA originally 'bound' to hnRNPs was associated with rapidly sedimenting (greater than 30 S) RNA (at 50 mM NaCl) suggesting their association by RNA-RNA hydrogen bonds. When the concentration of NaCl was 500 mM, 31% of the U1 RNA was associated with large RNA. Hence, approximately 30% of the U1 RNA molecules originally 'bound' (or about 15% of the total nuclear U1 RNA) were found to be associated by RNA-RNA hydrogen bonds while the remainder of the binding of U1 RNP to hnRNP was by protein-protein and/or protein-RNA interactions.
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PMID:Interactions of U1 RNP with heterogeneous nuclear RNA in rat Novikoff hepatoma nuclei. 608 66

As with normal human liver, both focal nodular hyperplasia (FNH) of the liver and a hepatocellular carcinoma were found to contain low levels of high affinity estrogen-binding components. In low-salt sucrose gradients the estrogen binders sedimented at 4S and 8S. Specificity studies indicated a requirement for estrogenic hormones. Progestin-binding studies using labeled and unlabeled ORG 2058 revealed high levels of specific binding in FNH and normal liver cytosol, whereas only insignificant amounts of ORG 2058 binding was found in the hepatocellular carcinoma. As judged by the high apparent dissociation constant (4-14 X 10(-8) mol/l) of the ORG 2058 - binder complex, the apparent lack of 8S binding in low-salt sucrose gradients and the atypical ligand specificity, the progestin receptor nature of these binding entities is unlikely. In contrast, normal liver, FNH, and the hepatocellular carcinoma were found to contain significant quantities of glucocorticoid receptors.
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PMID:Steroid receptor status of focal-nodular hyperplasia of the human liver. 608 20

Five chromatographically distinct DNA-dependent ATPase activities have been identified in high salt-detergent extracts of the Novikoff hepatoma. One of these, ATPase III, has been purified to apparent homogeneity as judged by polyacrylamide gel electrophoresis and has a specific activity of 12 mumol of ATP hydrolyzed min-1 (mg of protein)-1. The enzyme, a dimer of Mr 65000 subunits, has a sedimentation coefficient of 7.0 S in both high salt and low salt, a Stokes radius of 43 A, and a frictional coefficient of 1.31. In the presence of Mg2+ ion and a polynucleotide effector, the enzyme catalyzes hydrolysis of ATP or dATP to a diphosphate with a Km of 206 microM and 110 microM, respectively, for the two substrates. Although single-stranded effectors are preferred, the enzyme has significant activity with double-stranded effectors. The Km for effector is 0.4 microM (nucleotide). The analogues adenosine 5'-O-(3-thiotriphosphate) (ATP gamma S), dideoxyadenosine triphosphate (ddATP), and adenosine 5'-(alpha, beta-methylenetriphosphate) (alpha, beta-Me-ATP) are competitive inhibitors of the enzyme while adenosine tetraphosphate (ATP-P), 8-bromoadenosine 5'-triphosphate (8-Br-ATP), 5'-adenylyl imidodiphosphate (AMP-PNP), and adenosine 5'-(beta, gamma-methylenetriphosphate) (beta, gamma-Me-ATP) do not inhibit. The enzyme is insensitive to nalidixic acid, novobiocin, and berenil but is sensitive to N-ethylmaleimide. ATPase III is capable of stimulating DNA polymerase beta on duplex DNA, but this effect is abolished in the presence of ATP gamma S. Polymerase stimulation is further enhanced in the presence of a single-stranded DNA-binding protein. These data suggest that ATPase III may play a role in DNA repair.
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PMID:Deoxyribonucleic acid dependent adenosinetriphosphatases from the Novikoff hepatoma. Characterization of a homogeneous adenosinetriphosphatase that stimulates DNA polymerase beta. 612 27

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


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