Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Detergent extracts of polyoma virus-infected mouse cells contain three major proteins of approximately 100,000--108,000 (100K), 55,000 (55K) and 21,500 (22K) daltons, which react with sera obtained from rats carrying tumors induced by the virus. A comparison of the 35S-methionine-, 3H-leucine- and 3H-proline-labeled tryptic peptides of each of these proteins by cation-exchange chromatography followed by descending paper chromatography has shown that: at least five peptides are shared by all three T-reactive proteins; at least three peptides are shared by the 55K and 22K proteins, but not by the 100K protein; at least three peptides are found only in the 22K protein; at least six peptides are found only in the 55K protein; and at least sixteen peptides are found only in the 100K protein. The results are consistent with the hypothesis that the polypeptide chains of the 100K, 55K and 22K dalton tumor antigens of polyoma virus share a common virus-coded amino terminal region. The data also suggest that there is a portion of the polypeptide chains (probably immediately adjacent to the common amino terminal region of the molecules) that is shared by the 55K and 22K proteins, but not by the 100K protein (perhaps because this portion of the genetic information is spliced out of the messenger RNA coding for the 100K protein). The facts that all the peptides common to the 100K and 55K proteins are also found in the 22K protein and are thus assigned to the common amino terminal region of the molecules, and that there are several peptides unique to the 100K protein, as well as several peptides unique to the 55K protein, suggest that the presumed carboxy terminal portion of the polypeptide chain of the 100K protein is considerably, if not entirely, different from that of the 55K protein.
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PMID:Three species of polyoma virus tumor antigens share common peptides probably near the amino termini of the proteins. 21 27

The role of a plasma inhibitor of erythropoiesis is evaluated in rats with Walker-256 carcinoma (W-256). Plasma from tumor-bearing rats was treated by gel filtration chromatography (Sephadex G-150) and fractions were combined into four pools on the basis of mol. wt. Inhibitory activity was assayed by adding an aliquot of the plasma fractions to normal rat marrow cells which were cultured for 24 hr with and without erythropoietin. 59Fe-heme synthesis, [3H]thymidine DNA synthesis, and 14C-leucine protein synthesis were studied. The results indicated that cultures containing the high mol. wt. pool (greater than 400,000 daltons) had significantly decreased heme, DNA and protein synthesis. This inhibitor also diminished the response to erythropoietin in polycythemic mice. The lower mol. wt. pool stimulated heme synthesis in vitro. To identify the inhibitor further, plasma lipoprotein classes were isolated by density gradient ultracentrifugation. The very low density lipoprotein (VLDL) and chylomicron fractions markedly inhibited DNA, protein and heme synthesis. Low density and high density lipoprotein fractions were inactive. A lipoprotein inhibitor of erythropoiesis was also identified in cancerous ascitic fluid, and to a lesser degree, in normal rat plasma. We suggest that this VLDL inhibitor of marrow erythropoiesis is a contributing factor in the anaemia of cancer.
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PMID:Liproprotein inhibitor of bone marrow cells in tumor-bearing rats. 22 31

Injection of L-1-tosylamido-2-phenylethyl chloromethyl ketone (TPCK) at a level of 10 mg/100 g body weight inhibited the incorporation of 3H-labeled amino acids into protein in Morris hepatomas 7777and 9618A2. The degree of inhibition was similar in cytoplasmic proteins and in histone and nonhistone nuclear protein fractions. There was no inhibitory effect on 3H-labeled amino acid incorporation in the livers of the tumor-bearing rats. The inhibitory effect of N-tosyl-L-lysine chloromethyl ketone (TLCK) on incorporation of 3H-labeled amino acids was observed in both the slowly growing hepatoma 7787 and the rapidly growing hepatoma 7777. In hepatoma 7777, TLCK (2.5 mg/100 g body wt) exerted a greater inhibitory effect on incorporation when administered 60 minutes before [3H]leucine injection than when injected simultaneously. Studies on tissue uptake of amino acids, thymidine, and phosphate indicated that inhibitory effects of TPCK and TLCK on active transport may be a major factor in the action of these drugs on macromolecular synthesis. The inhibitory effects of TPCK and TLCK seen in transplanted hepatomas and a colon tumor were not generally seen in normal tissues of the tumor-bearing rats.
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PMID:Selective effects of two chloromethyl ketones on amino acid and phosphate uptake in rat liver and tumors. 28 72

Poly(A)-containing RNA isolated from bovine and mouse pituitaries and a mouse pituitary thyrotropic tumor was translated in a wheat germ cell-free biosynthetic system. A precursor of the glycoprotein hormone alpha subunit, "pre-alpha," was immunoprecipitated from the translation mixtures with antiserum against bovine luteinizing hormone (LH; lutropin) alpha. The specificity of the immunoprecipitation was shown by competition with authentic bovine LHalpha and lack of competition with bovine thyroid-stimulating hormone (TSH; thyrotropin) beta. Bovine and mouse pre-alpha subunits migrated identically in sodium dodecyl sulfate gradient polyacrylamide slab gels with an apparent molecular weight of about 17,000. Pre-alpha comprised 2-3% and 20-30% of the total proteins translated with pituitary and pituitary tumor mRNA, respectively. Microanalysis of amino acid sequence of the pre-alpha subunits containing various radiolabeled amino acids gave the following partial sequence for mouse tumor pre-alpha: [Formula: see text] Met was also found in positions 1, 14, and 17 in mouse pituitary pre-alpha but only in residue 1 of the bovine pituitary pre-alpha subunit. Leu was found in identical positions in bovine pituitary pre-alpha, with an additional Leu in position 17. Leu in the common positions (12, 15, 19, and 22) has also been found in human choriogonadotropin pre-alpha subunit [Birken, S., Fetherston, J., Desmond, J., Canfield, R. & Boime, I. (1978) Biochem. Biophys. Res. Commun. 85, 1247-1253]. The data demonstrate that pituitary as well as placental glycoprotein hormone alpha subunits are synthesized with an amino-terminal hydrophobic extension, in accord with the "signal hypothesis" for secreted proteins. Furthermore, the positions of the hydrophobic amino acid Leu have been strictly conserved in pre-alpha subunits from various species and in two different tissues, the pituitary and placenta.
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PMID:Comparison of bovine and mouse pituitary glycoprotein hormone pre-alpha subunits synthesized in vitro. 29 99

75Se-Selenomethionine is often used for the isotope scanning of pancreas. However, it is desired to develop excellent pancreas scanning agens that give more specific distribution and less radiation hazards than the agents. Pancreas has a high ability to incorporate amino acids into its cells and to utilize the acids for the synthesis off proteins and enzymes. On the basis of this preferential uptake of amino acids, radioactive iodine-labeled amino acids and peptides, gamma-131I-iodo-alpha-aminobutyric acid, N-2-131I-monoiodoacetyl-L- and D-leucines, L- and D-leucine 2-131I-iodoethyl esters, 125I or 131I-labeled dipeptides, and insulin 125I-A and 131I-B chains, were prepared and assayed for their distribution in mouse organs and Ehrlich ascites tumor cells. Radioactivity of these labeled compounds incorporated into pancreas was almost the same as that of liver and spleen, and considerably smaller than that of stomach, duodenum and kidney. Since a high incorporation into stomach was seen also after the administration of 125I-sodium iodide, it was suggested that iodine ions were liberated in vivo from the labeled compounds within a short time.
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PMID:[Fundamental studies for the development of pancreas scanning agents--preparation of radioactive iodine-labeled amino acids and peptides and their distribution (author's transl)]. 40 31

The biosynthesis and secretion of a glycosylated, K-type immunoglobulin light chain (K-46) was studied in a mouse myeloma tumor, mineral oil plasmacytoma-46B. Viable single cell suspensions were prepared from excised tumors and optimal conditions were established for incorporation of amino acid and carbohydrate precursors into the protein synthesized and secreted by the cells. The glucose analog, 2-deoxy-D-glucose, was utilized as an inhibitor of glycosylation to determine the role of glycosylation in the biosynthesis, intracellular transport, and export of the protein from the cell. It was determined that 6 mM 2-deoxyglucose prevents the incorporation of glucosamine, mannose, and galactose into secreted protein, but permits the incorporation of leucine at approximately 40% of control values. The nonglycosylated protein, secreted in the presence of 2-deoxyglucose, was characterized as a nonglycosylated form of K-46 light chain by the following criteria: (a) electrophoresis in polyacrylamide gels containing sodium dodecyl sulfate, (b) reactivity of the nonglycosylated protein with antisera prepared against native, fully glycosylated, K-46 light chain, (c) analysis of the protein by gel filtration techniques, (d) behavior of the protein on lectin-derivatized Sepharose, and (e) analysis of tryptic peptides derived from the protein. We have concluded that 2-deoxyglucose-inhibited cells synthesize and secrete the normal polypeptide chain of K-46 devoid of its carbohydrate side chain indicating that glycosylation is not an essential step in the biosynthesis, intracellular transport, or export of this protein that is normally synthesized and secreted in a glycosylated form. Under conditions of 2-deoxyglucose inhibition, the nonglycosylated form of K-46 light chain constitutes a significantly greater proportion of accumulated intracellular protein, suggesting that the biosynthesis of the polypeptide chain of K-46 light chain proceeds at a nearly normal rate, but that the absence of the carbohydrate side chain of the protein retards, but does not prevent, the intracellular transport of the protein and its export from the tumor cell.
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PMID:Glycoprotein biosynthesis in myeloma cells. Characterization on nonglycosylated immunoglobulin light chain secreted in presence of 2-deoxy-D-glucose. 40 89

Three AKR lymphomas displaying B cell and T cell characteristics have been described. Because of the proclivity of normal AKR/J mice to develop T cell lymphomas, and the rarity of lymphomas with dual characteristics, the B cell markers of these tumors were studied more intensively. Fluorescence data with class-specific anti-immunoglobulin reagents demonstrated that the tumor cells stained only with class-specific anti-IgM reagents. Because of the possibility that the surface Ig was passively acquired and of reports that certain anti-mu-chain sera react with "IgT", chemical characterization of the immunoglobulin molecules was performed. Using 3H-leucine internal labeling, we showed that all three tumor lines synthesized the immunoglobulin found on their surface, and that the immunoglobulin had the chemical and immunologic characteristics most typical of monomeric surface IgM, and was composed of mu-chains and light chains. The Ia antigens found on these cells were also examined. These antigens were also synthesized by the cells and were present in the same molecular form and in the same approximate quantity as Ia antigens on normal spleen cells.
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PMID:Synthesis and characterization of membrane immunoglobulin, Ia, and H-2 molecules of thy 1+ AKR/J lymphomas. 41 Aug 82

Mammary tumors induced in outbred Sprague-Dawley rats by 7,12-dimethylbenz]a]anthracene were excised, cut into 1- to 2-mm3 pieces, and then autotransplanted sc along the mammary line at six sites. Following an average period of 20--30 days, these autografts grew to approximately 2 cm in diameter in 32 of 48 rats (67%). Autografts in the other 33% of the rats remained dormant. Mammary tumors transplanted into allogeneic hosts failed to grow. Tumors derived from autotransplantation were indistinguishable from their primary tumors with respect to their histologic features, the nature of hormone dependency, the content of estrogen receptors, and their ability to incorporate [3H]leucine. Furthermore, autotransplanted tumors derived from a single primary tumor varied little with regard to the preceding parameters; thus they provided an opportunity for serial sampling of individual tumors for repeated morphologic and biochemical evaluations.
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PMID:Multiple autotransplantation of rat mammary induced by 7,12-dimethylbenz[a]anthracene: brief communication. 41 30

We have examined the interaction of dexamethasone with the ZR75-1 human breast cancer cell line to determine if glucocorticoids might directly inhibit growth of breast cancer cells. Growth of these cells in serum-free medium was stimulated significantly by physiological concentrations of insulin (0.1 to 1.0 nM). Pharmacological concentrations of dexamethasone (10 nM) reduced cell number below that found in controls and nearly abolished the effect of insulin after several days in culture. Thymidine and uridine, but not leucine, incorporation into macromolecules or acetate incorporation into fatty acids were similarly inhibited by dexamethasone in the presence of absence of insulin. Dexamethasone did not inhibit insulin effects by altering insulin receptor affinity or concentration, as determined by Scatchard analyses of insulin binding. Net thymidine uptake into the trichloroacetic acid-soluble fraction of the cell was stimulated by insulin and inhibited by dexamethasone also inhibited thymidine kinase activity multiple potential sites of glucocorticoid action that directly oppose the effects of insulin. They also suggest that glucocorticoids have a direct inhibitory effect on proliferation of human breast cancer cells, which may help explain breast tumor regression following pharmacological glucocorticoid therapy.
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PMID:Direct inhibition of growth and antagonism of insulin action by glucocorticoids in human breast cancer cells in culture. 44 41

Noncytotoxic aqueous extracts of esophageal tumors (TEx) inhibit the spontaneous uptake of 3H-thymidine by human peripheral blood mononuclear cells (PBM). TEx also inhibits mitogen- and antigen-induced PBM blastogenesis, mitogenesis, 3H-thymidine uptake, and 3H-leucine incorporation. Inhibition is reversible and is mediated by a heat-labile protein with a m.w. of approximately 70 to 80,000 daltons. Inhibitory activity is not due to trivial binding of mitogen or neucleotide by the inhibitor, nor is it entirely tumor specific since similar but quantitatively less activity is extractable from adjacent normal esophageal mucosa. Assorted cell surface membrane phenomena such as contact inhibition of in vitro endothelial cell proliferation, lymphocyte E rosette formation, and cap formation are unaffected by TEx. In contrast, immunoglobulin synthesis by pokeweed mitogen-stimulated PBM is enhanced by TEx. The potential importance of the local production of immunoregulatory agents like TEx in the immunologic control of tumor cell growth is discussed.
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PMID:Immunoregulatory properties of human esophageal tumor extract. 44 92


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