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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The content of poly(A)-containing RNA in subcellar fractions has been investigated both in cortisone-treated rat liver and experimental hepatoma cells. The fractions included nuclei, cytoplasm, mitochondria, free and membrane-bound polyribosomes. 1) In both cases of genome activation (cortisone induction and hepatoma cells) an increase in poly(A) content of all subcellular fractions except free polyribosomes was observed. 2) Cortisone was found to induce elongation of poly(A) segments detected in both nuclei and cytoplasm. 3) An increase in the poly(A) block size also was found to be stimulated in nuclei and cytoplasm of hepatoma cells. 4) The observed elongation in poly(A) length occurred against the background of an increase of the population of of poly(A)-RNA's.
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PMID:Studies of poly(A+)-RNA in mouse hepatoma and cortisone-stimulated rat liver. 20 62

Rat and mouse liver mitochondria, when centrifuged in a sucrose density gradient (25--50%, w/w), showed the presence of heavy (H) and light (L) subfractions with buoyant densities 1.185 and 1.170--1.165 g/ml, respectively. Mild treatment with digitonin or EDTA (30 mM) shifted H-subfraction of mitochondria into the lighter zone of the gradient and as a result of this the mitochondria were distributed as a homogenous band with buoyant density 1.170--1.165 g/ml. Mitochondria isolated from both MD hepatoma and Zajdela rat hepatoma were characterized by a homogenous banding with buoyant density 1.160--1.165 g/ml. Regarding to this, the content and patterns of polyribosomes bound to outer membranes of mouse tumor mitochondria were studied. Analysis of polyribosomes as well as the results of RNA polyacrylamide gel electrophoresis indicate that the content of these polyribosomes in tumor mitochondria is less than that in normal liver ones. However, the decrease of cancer cell membrane-bound polyribosomes cannot account for the differences in buoyant densities of mitochondria from normal and tumor tissues.
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PMID:Behavior of mitochondria from normal and tumor cells in isopycnic sucrose gradients. 20 78

The turnover of messenger RNA (mRNA) in two intrahepatically transplantable hepatoma (5123 and 19) and host livers of Buffalo rats was evaluated with four different approaches. [14C]Orotic acid incorporation into the rapidly labeled peak between 18S and 4S of total polyribosomal RNA was measured. In vitro RNase assay of [14C]orotic acid-labeled mRNA of polyribosomes was utilized. The decay of mRNA as reflected by disaggregation of free and membrane-bound polyribosomes at intervals after actinomycin D treatment was determined. The incorporation of [14C]orotic acid into polyadenylic acid-mRNA of free and membrane-bound polyribosomes was assayed. The results revealed that the turnover of mRNA of total, free, and membrane-bound polyribosomes was greater in the host livers than it was in the two hepatomas. In host livers the turnover of mRNA of the free polyribosomes was greater than that of the membrane-bound polyribosomes. In the two hepatomas the turnover of mRNA of free polyribosomes was at a similar rate as that of membrane bound polyribosomes. Hepatoma 19, which grow more rapidly and is less differentiated morphologically than is hepatoma 5123, appeared to have a slower turnover of mRNA than did hepatoma 5123. Measurement of RNase activity revealed greater activity in host livers than in hepatomas.
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PMID:Turnover of messenger RNA in transplantable hepatomas and host liver of rats. 20 54

The description is given of the distribution of poly(A)-containing mRNA in different subcellular fractions (nuclei, mitochondria, free- and membrane-bound polyribosomes) from the normal tissues hepatoma MD and chick Rous. The amount of poly(A)-RNA is found to increase in all tumor cell fractions, but free polysomes.
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PMID:[The protein-synthesizing apparatus in chemically- and virus-induced tumors]. 22 38

Amoung of prelabelled mRNA was unaltered in Zajhdel ascites hepatoma of rat cells within 3.5-4 hrs under conditions of treatment with actinomycin D. Due to combined effect of actinomycin D and cycloheximide the content of mRNA in the hepatoma cells was rapidly decreased. Degradation of mRNA occurred in membrane-bound polyribosomes, free polyribosomes and in cytoplasmic mRNP-particles /informosomes/ as a result of the effect of cycloheximide. Simultaneously with these phenomena, distinct increase in activity of acid and alkaline RNAases was observed in cytoplasma of the hepatoma cells; activity of endoRNAase from membrane-bound and free polyribosomes of the hepatoma was also markedly increased. Cycloheximide did not affect the activity of polynucleotide phosphorylase in polyribosomes of the hepatoma cells. Labile proteins, responsible for inhibition of RNAses appeart to participate in regulation of mRNA stability in malignant cells.
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PMID:[mRNA breakdown in tumor cells in vivo under cycloheximide protein synthesis inhibition]. 51 39

The early steps in the biosynthesis of glycoproteins associated with the plasma membranes of rat hepatoma tissue culture cells has been analyzed. By measuring the effect of tunicamycin on the incorporation of [3H] mannose and [3H] fucose into cell glycoproteins, it was determined that an interval of about 1 h was required to transfer the glycoprotein from site of mannosylation to the site of fucosylation. This result was corroborated by an analysis of the time required for the appearance of either mannose or fucose-labeled glycoproteins at the cell surface. The separation of membrane glycoproteins by a two-dimensional gel system allowed the visualization of the modifications leading to both size and charge heterogeneity of these proteins. By following the changes in electrophoretic mobility introduced into membrane glycoproteins during a chase period after a pulse labeling, the time course of these molecular alterations could be estimated. Several glycoproteins have apparently higher rates of synthesis than the bulk of membrane-associated glycoproteins. Most of these glycoproteins were released within 2 h after biosynthesis from the intracellular membrane fraction and appear after 3 h in the medium. In addition to the glycoproteins that contain both mannose and fucose and that show a high degree of charge heterogeneity, there are other membrane-bound species that are not noticeably modified by the incorporation of fucose or sialic acids. These glycoproteins could represent constituents limited to the internal membrane system of the HTC cell.
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PMID:Biosynthesis of membrane glycoproteins in rat hepatoma tissue culture cells. 54 34

The distribution of poly(A)-enriched mRNA in nuclei, mitochondira, free and membrane-bound polyribosomes from normal C3HA mouse and Syrian hamster livers and normal chicken fibroblasts has been compared with that in corresponding subcellular fractions in a transplantable, chemically induced MD hepatoma, non-virus-producer hamster and virus-producer chicken Rous sarcomas. It has been shown that the content of poly(A)-RNA is increased in all tumour fractions except in free polyribosomes. The distribution of different classes of polysomes i.e. free, membrane-bound and mitochondrial outer-membrane-associated polysomes in tumour cells was changed in comparison to that in normal cells. It is concluded that in tumours of chemical and viral origin, the observed changes in the two components of the protein-synthesizing apparatus occur simultaneously.
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PMID:Polyadenylated RNA molecules and polyribosomes in tumours of chemical and viral origin. 63 36

The nuclease activities of proteins, constituents of cytoplasmic ribosomes obtained from normal liver rats (Wistar) and C3HA mice as well as from hepatomas (both solid and ascites forms) transplanted into the above animals, were studied. RNA in membrane-bound ribosomes of normal rat liver incubated at 37 degrees C undergoes endogeneous hydrolysis resulting in formation, apart from acid-soluble products, of 6S, 8S and 11S fragments comprising 15 to 20% of the original amount of RNA. In contrast, in hepatoma membrane-bound ribosomes RNA treated likewisely remains intact. The proteins responsible for the RNase activity isolated from ribosomes were subsequently fractionated using ammonium sulfate and chromatography on DEAE-Sephadex columns and their properties were studied. The RNase activity completely disappeared from the membrane-bound ribosomes of Zajdela, 27 rat hepatomas and Guelstein hepatoma 22A, but not from the slow growing Guelstein hepatoma 48.
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PMID:[Nuclease activity of the cytoplasmic ribosomes of hepatocytes and several experimental hepatomas]. 71 53

The messenger activity for fructose 1,6-bisphosphate aldolase (EC4.1.2.13) (aldolase) A isozyme has been characterized in the polysome- or the messenger RNA-directed, protein-synthesizing system using the pH 5 fraction of rat liver or wheat germ extracts, respectively. The subunit of aldolase A synthesized in vitro was detected by immunoprecipitation with anti-aldolase A antibody raised in chickens followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The synthesis of the enzyme depended on the addition of polysomes or polyadenylate-containing RNA of rat ascites hepatoma AH 7974 cells which show a complete shift of aldolase isozyme to type A, whereas polysomes of adult rat liver were inactive. The messenger activity for aldolase A was present exclusively on free polysomes but absent on membrane-bound polysomes and in the soluble supernatant fraction of AH 7974 cells. The size of aldolase A messenger RNA determined by formamide-containing sucrose density gradient centrifugation was approximately 5.8 X 10(5) daltons corresponding to 1650 nucleotides. Taking into account the number of amino acid residues in the aldolase A subunit, approximately 400 nucleotides correspond to the noncoding region of aldolase A messenger RNA.
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PMID:Characterization of messenger RNA for fructose 1,6-bisphosphate aldolase A isozyme of rat ascites hepatoma AH 7974 cells. 76 Dec 23

This paper describes the finding of monoclonal antibody (MoAb) more reactive to cell-surface alpha-fetoprotein (AFP) than to free AFP by using a simple in vitro system. Twelve mouse MoAbs, ten IgG1, one IgG2a and one IgG2b, against human AFP from hepatocellular carcinoma were obtained by the cell fusion technique. Each hybridoma supernatant was assayed by enzyme-linked immunosorbent assay (ELISA) to solid-phase AFP. The assay results showed that two MoAbs, 67D and 80G, were most reactive to AFP. 80G had a higher affinity constant than 67D, while the both reactions were similarly difficult to inhibit by free AFP in ELISA. 67D and 80G reacted with AFP on the surface of ethanol-fixed cells from the human hepatoma cell line HuH-7 and this reaction was also difficult to inhibit by free AFP in Cell ELISA. Furthermore, Western blot analysis showed that 67D and 80G were more reactive to membrane-bound AFP than other antibodies. These findings first suggest that there could be anti-AFP MoAbs preferably binding to cell-surface AFP rather than to serum AFP.
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PMID:Monoclonal antibodies against human alpha-fetoprotein more reactive to cell-surface alpha-fetoprotein than to free alpha-fetoprotein. 128 96


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