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 specificity of lactoperoxidase-catalyzed iodination for the proteins of the hepatoma tissue culture cell plasma membrane was examined by histochemical, biochemical, and cell fractionation techniques. Light microscope autoradiography of sectioned cells shows the incorporated label to be localized primarily at the periphery of the cell. Most of this label can be released from the cell by trypsin but not by collagenase or hyaluronidase. The label is recovered from the cells as either monoiodotyrosine or diiodotyrosine after hydrolysis of cell extracts with a mixture of proteolytic enzymes. The label co-purifies during cell fractionation with an authentic liver cell plasma membrane marker enzyme, 5'-nucleotidase. Thus, the incorporated iodide is itself a valid marker for those membrane polypeptides having tyrosine residues accessible to the lactoperoxidase. The polypeptide complexity of the purified plasma membrane was examined by high resolution dodecyl sulfate-polyacrylamide gel electrophoresis. At least 50 polypeptides in the membrane are accessible to iodination. These polypeptides probably represent the bulk of the protein mass of the membrane and iodinating them does not affect cell viability, growth rate, or cell function. Labeling experiments with fucose and glucosamine show that at least nine of the iodinated peptides may be glycoproteins.
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PMID:Proteins of the hepatoma tissue culture cell plasma membrane. 0 57

Purification of alpha-fetoprotein from mouse hepatoma BW7756 extracts was performed using ammonium sulfate precipitations, gel filtration, ion-exchange chromatography and isoelectric focusing. These procedures produced a 5.6% yield of alpha-fetoprotein with 96% purity. Polyacrylamide slab gel electrophoresis, extended agarose electrophoresis and immunoelectrophoresis demonstrated that mouse hepatoma alpha-fetoprotein migrated at pH 8.6 as a rapid alpha1, or postalbumin globulin. Crossed antibody electrophoresis of the agarose zone containing alpha-fetoprotein failed to demonstrate microheterogeneity. Molecular weight analysis of the mouse hepatoma alpha-fetoprotein on a calibrated Sephadex G-200 column yielded a value of 72 000-73 000 for the native protein. Sodium dodecyl sulfate gel electrophoresis subsequently demonstrated a single polypeptide chain with a molecular weight of 72 000. Amino acid analysis showed the alpha-fetoprotein to be an acidic protein dominated by hydrophobic residues. The total carbohydrate content was 5.5%, and 3 mol of sialic acid were detected per mol of alpha-fetoprotein. Although neutral sugars were the principal class present, galactosamine was the most abundant single sugar detected.
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PMID:Isolation and characterization of alpha-fetoprotein from the mouse hepatoma BW7756. 6 68

Human alpha-fetoprotein has been isolated from the serum and ascitic fluid of a patient with hepatoma by a combination of immunoadsorbent column chromatography and Sephadex G-150 gel filtration. Human alpha-fetoprotein is a sialylated glycoprotein with an estimated molecular weight of 67 500, composed of a single-chain polypeptide of approximately 580 amino acid residues and 3.6% carbohydrate. It is a negatively charged protein with an acid isoelectric point (pH 4.57). In addition to the monomeric form of alpha-fetoprotein, we have identified human alpha-fetoprotein polymers, including dimeric and trimeric forms, which dissociate to the monomer only upon exposure to disulfide-reducing reagents, implying that their formation is dependent upon intermolecular disulfide bonds. These polymers are found in human alpha-fetoprotein isolated by isoelectric focusing in both the major (pI 4.57) and minor (pI 5.2) alpha-fetoprotein fractions. The first 17 residues of the NH2-terminal amino acid sequence of the hepatoma-derived human alpha-fetoprotein have been identified. Fetal alpha-fetoprotein is indistinguishable from hepatoma alpha-fetoprotein by several criteria, including immunoelectrophoresis, acryalmide gel electrophoresis, and proclivity for dimerization.
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PMID:Studies on human alpha-fetoprotein. Isolation and characterization of monomeric and polymeric forms and amino-terminal sequence analysis. 7 Feb 28

The PLC/PRF/5 cell line derived from a human hepatoma produces hepatitis B surface antigen (HBsAg) in 22-nm particles of the same buoyant density as those found in the serum of infected patients. The HBsAg particles from this cell line were labeled with [35S]methionine and purified, and the polypeptides were compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis with those of serum-derived particles. The two major polypeptides of serum-derived HBsAg particles (p20 and p23) were found in the same relative amounts in the particles from the cell line. The three smallest of the five minor components observed in HBsAg particles from serum were present in particles from the cell line. These polypeptides (p31, p36, and p43), as well as p20 and p23, were precipitated with anti-HBs-containing serum. The two largest polypeptides of serum particles (p49 and p66) were not detected in particles from these cells. When the PLC/PRF/5 HBsAg particles were radiolabeled with tritiated sugars, p23, and not p20, was found to contain radioactivity, indicating that the pattern of polypeptide glycosylation is similar to that of serum HBsAg. None of the other possible gene products of hepatitis B virus was detected in the PLC/PRF/5-derived HBsAg particles, in the cells, or in the cell supernatants.
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PMID:Polypeptides of hepatitis B virus surface antigen produced by a hepatoma cell line. 9 75

Bovine pineal polypeptide extract (PPE) exerted an anti-tumor effect on mouse-transplantable tumors: mammary cancer (RSM), squamous cell cervical carcinoma (SCC), hepatoma-22a and lympholeukemia LIO-1, and had no effect on Harding-Passey melanoma and leukemia L-1210. It was shown that PPE possessed the ability to decrease the incidence of DMBA-induced mammary adenocarcinomas in rats. The daily administration of 0.5 mg PPE prolonged the life span of rats by 25% and failed to influence spontaneous tumor development. The arguments in favor of a possible mechanism of anti-tumor action of the pineal gland are submitted. It is suggested that the anti-tumor effect of PPE may occur when the syndrome of cancrophilia is induced by tumor transplantation or chemical carcinogens.
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PMID:Study of the anti-tumor effect of polypeptide pineal extract. 11 14

Nuclear ribonucleoprotein (RNP) complexes that contain the U1 and U2 RNA of chromatin of Novikoff hepatoma cells were extracted with 0.01 M Tris-HCl (pH 8.0) after the nuclei were initially washed with 0.075 M NaCl and 0.025 M EDTA (pH 8.0). These RNP complexes were purified by chromatography on Sepharose 6B columns and centrifugation on sucrose density gradients. The identity of the U1 and U2 RNA in these particles was established by their electrophoretic mobility in polyacrylamide gels and their T1 RNase fingerprints which were identical with those of authentic U1 and U2 RNA (R. Reddy et al. (1974), J. Biol. Chem.249, 6486-6494; H. Shibata et al. (1974), Mol. Cell. Biochem. 4, 3-19). The nuclear riboncleoproteins had a buoyant density of 1.47 g/ml in CsCl gradients. Two-dimensional polyacrylamide gel electrophoresis of their proteins showed these RNP complexes contain 10 polypeptide spots, of which two are phosphorylated in vivo.
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PMID:Nuclear ribonucleoprotein complexes containing U1 and U2 RNA. 16 94

Various aspects of hormone treatment of tumor cells are reported; it is shown that following treatment with certain hormones, the cells are less susceptible to killing by antibody and complement. The diethylnitrosamine-induced guinea pig hepatoma, designated Line 1, is susceptible to killing by anti-Forssman immunoglobulin M (IgM) antibody and guinea pig complement (GPC) but not by specific antitumor antibody and GPC. The antigenetically distinct Line 10 hepatoma, when sensitized with either antibody, is susceptible to killing by human complement (HUC) but not by GPC. Strain 2 of Servall-Wright male guinea pigs were used. 2 antigenetically distinct diethylnitrosamine-induced hepatic tumors (ascites form), Lines 1 and 10, passed in Strain 2 guinea pigs, were collected and suspended in RPMI 1640-20% FCS. Toxicity assays were performed in VBS-gel. The hormones used were hydrocortisone sodium succinate, prednisolone sodium succinate, NSC9151, bovine insulin, L-epinephrine methyl ether HC1, DL-epinephrine, beta-estradiol, testosterone, pork insulin, chicken insulin, pork proinsulin, pork DAA insulin, and the A and B chains of pork insulin. Tumor cells were cultured in 10-ml volumes of RPMI 1640-20% FCS in plastic Petri dishes. After incubation, cell cultures were washed 5 times in VBS-gel and tested for their susceptibility to killing by antibody and complement. Rabbit antiserum to sheep Forssman antigen was prepared and stored at -20 degrees until used. Tumor specific rabbit Antilines 1 and 10 antisera were prepared and similarly stored. Results of tests show that Line 1 tumor cells incubated in a medium containing the polypeptide hormone, insulin, the catecholamine, L-epinephrine HCl, or the glucocorticoid steroids, hydrocortisone sodium succinate, or prednisolone sodium succinate were rendered resistant to killing byanti-Forssman IgM antibody and GPC. This effect was dependent on hormone concentration, temperature, and time. Effects were reversible. Similar results were obtianed with Line 10 cells under attack by specific antitumor and HUC or anti-Forssman antibodies. Less physiologically active analogs of the hormones did not have this effect. Tumor cells showed maximum resistance within 30-60 minutes of exposure to the hormones and reverted to the sensitive state within 4 hours. Resistance of the cells to killing was observed at 37 degrees but not at 0 degrees. It is concluded that the effect of hormone treatment was not due to a direct inactivation of bound or fluid-phase complement components by the hormones or to a decrease in the ability of the cells to bind complement-fixing antibody.
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PMID:Inhibition of antibody-complement-mediated killing of tumor cells by hormones. 18 62

Poly(A) polymerase was extracted from isolated nuclei of rat liver and a rapidly growing solid tumor (Morris hepatoma 3924A). The enzyme from each tissue was purified by successive chromatography on DEAE-Sephadex, phosphoecllulose, hydroxyapatite and QAE-Sephadex. Purified enzyme from both liver and tumor was essentially homogeneous as judged by polyacrylamide gel electrophoresis. Under nondenaturing conditions, enzyme activity corresponded to visible protein and, upon denaturation, a single polypeptide was detected. The enzymes had absolute requirements for Mn2+ as the divalent ion, ATP as the substrate and an oligonucleotide or polynucleotide as the primer. Both enzymes were inhibited by sodium pyrophosphate, N-ethylmaleimide, Rose Bengal, cordycepin 5'-triphosphate and several rifamycin derivatives. The reactions were unaffected by potassium phosphate, alpha-amanitin and pancreatic ribonuclease. However, the liver and hepatoma enzymes differed from each other with respect to apparent Km, primer saturation levels and sensitivity to pH changes. The most striking differences between the enzymes were in their calculated molecular weights (liver, 48000; hepatoma, 60000) and amino acid compositions. Finally, the level of the hepatoma enzyme relative to that of the liver enzyme was at least 1.5-fold higher when expressed per mg DNA.
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PMID:Nuclear poly(A) polymerase from rat liver and a hepatoma. Comparison of properties, molecular weights and amino acid compositions. 18 50

Isolated plasma membrane fractions from rat liver and Morris hepatoma 5123D and 7777 were labelled with radioiodine 125I by a chemical or enzymatic procedure and then were solubilized in 2 per cent solution of sodium dodecyl sulphate containing 1 per cent 2-mercaptoethanol. Solubilized proteins were separated into 20--22 zones staining with Coomassie Brilliant Blue R-250 after disc gel electrophoresis (7.5 per cent polyacrylamide gel). The high similarity of electrophoretic patterns of polypeptide components of all three preparations of cellular membranes was found in distinction to apparent differnces in the amount and disposition of substances stained with Schiff's reagent. Some tentative conclusions were drawn on the disposition of proteins within membrane structure studied by the method of labelling by chemical and enzymatic procedures (distinguishing between extrinsic and integral proteins).
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PMID:Comparison of protein components of the plasma membrane fraction from rat liver and Morris hepatomas 5123D and 7777. 18 68

The feeding of carcinogenic 3'-methyl-4-dimethylaminoazobenzene (3'-MeDAB) in the early stages results in a change in the protein composition of the nuclear ribonucleoprotein particles of the rat liver. These particles are associated with newly synthesized RNA and it is assumed that they are involved in the processing and in the transport of this RNA. After 6 weeks of feeding of this azocarcinogen, the amount of one of the main polypeptides (apparent molecular weight 42 000) is decreased and after 10 weeks of feeding the particles are devoid of this polypeptide completely. Feeding of the non-carcinogenic p-aminoazobenzene (AB) is without any effect. The loss of this polypeptide is not characteristic for the malignant transformation. In the nuclear ribonucleoprotein particles isolated from hepatoma which has been induced by 3'-MeDAB this polypeptide is present in even higher proportion to other polypeptides than it is in particles isolated from liver cells of control animals. The 3'-MeDAB binds to the proteins of the liver nuclear ribonucleoprotein particles and interferes with the RNA processing. It is proposed that the changes in the composition of the protein moiety of the particles reflect changes in the population of liver cells leading finally to the selection of hepatoma cells which are resistant to the toxic effect of 3'-MeDAB on RNA processing.
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PMID:Protein composition of nuclear ribonucleoprotein particles isolated from liver of rats in the early stages of feeding of 3'-methyl-4-dimethylaminoazobenzene and from hepatoma induced by the same carcinogen. 20 12


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