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)

12-O-Tetradecanoyl-phorbol 13-acetate is a very effective tumor promotor and inflammatory agent and can act as a mitogen for a subset of T lymphocytes. We report here that even short exposure of lymphocytes to 12-O-tetradecanoyl-phorbol 13-acetate changes the balance between the levels of neutral ribonuclease and ribonuclease inhibitor. The most dramatic change occurs in a B-lymphocyte-enriched population. We find that most, if not all, of the neutral ribonuclease activity in circulating lymphocytes is associated with this population and that this activity is lost with exposure to 12-O-tetradecanoyl-phorbol 13-acetate. Both 12-O-tetradecanoyl-phorbol 13-acetate and phytohaemagglutinin increase the level of ribonuclease inhibitor in T cells. However, phytohaemagglutinin has no effect on the ribonuclease or inhibitor level of the B-cell-enriched population.
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PMID:The effect of 12-O-tetradecanoyl-phorbol 13-acetate on the ribonuclease activity of circulating human lymphocytes. 31 10

We investigated the ribonucleolytic breakdown of poly(U), poly(A), RNA trascribed from calf thymus DNA with E. coli RNA polymerase, ribosomal RNA, tRNA and mengovirus RNA by an enzyme fraction obrained from a postribosomal supernatant of Ehrlich ascites tumor cells. The single-stranded homopolyribonucleotides are preferentially degraded by the enzyme fraction with the production of ribonucleoside 5'-monophosphates. The RNase activity is completely dependent on the presence of Mg2+ ions and is highest at Mg2+ and K+ concentrations optimal for cell-free protein synthesis. Ribonucleoside 5'-monophosphates, ribonucleoside 2'(3')-monophosphates, ribonucleoside 2'(3'),5'-bisphosphates and transition state analogs consisting of vanadyl sulfate and either ribonucleosides or ribonucleoside 5'-monophosphates in a molar ratio 1:1 inhibit the ribonucleolytic activity of the enzyme fraction. The ribonucleoside 2'(3'),5'-bisphosphates and the transition state analogs are the most effective inhibitors. However, only in the presence of ribonucleoside 2'(3'),5'-bisphosphates a concomitant stimulation by 50 to 60% of poly(U)-directed polyphenylalanine synthesis is observed; all the other RNase inhibitors tested also inhibit polypeptide synthesis. The results of preliminary experiments show that poly(U) and ribonucleoside 2'(3'),5'-bisphosphates are well suited as ligands for affinity chromatography of ribonucleases from Ehrlich ascites tumor cells.
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PMID:Inhibition of ribonucleases by ribonucleotides and transition state analogs in cell-free extracts from Ehrlich ascites tumor cells. 32 84

The tRNA nucleotidyltransferase activity (3H-CMP incorporation into 3'-terminus of tRNApC) in cytoplasmic fractions of various types of cells such as Ehrlich ascites tumor cells, mouse liver and spleen cells, rat spleen, lymph node, and macrophages cells was found to be dependent on the concentrations of nucleoside 5'-triphosphates (ATP, GTP, UTP, dATP, dGTP, dCTP, and/or dTTP). The purified tRNA nucleotidyltransferase did not show such dependency. The dependency of the enzyme activity on nucleoside 5'triphosphates in the crude cytoplasmic fractions was possibly due to the presence of inhibitors which interfere with the repair system of defective 3'-termini of tRNA. Two kinds of inhibitors were distinguishable in the cytoplasmic fractions. One was unstable on heat treatment at 55 decrees C and showed ribonuclease activity for the tRNA 3'-terminus. The other which lacked ribonuclease activity was rather stable to the heat treatment and inhibited purified tRNA nucleotidyltransferase. The actions of both inhibitors were suppressed by nucleoside 5'-triphosphates.
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PMID:Effect of nucleoside 5'-triphosphates on tRNA nucleotidyltransferase activity in cytoplasmic fractions of various types of mammalian cells. 42 63

Tumor culture toxohormone (TCT) obtained from cultures of MBQA mouse tumor cells, a line derived from a methylcholanthrene-induced fibrosarcoma (CBA/J origin), suppressed the mitogenic responsiveness of mouse spleen cells (PHA, LPS) as well as the antibody formation to SRBC in vitro. The immunosuppressive activity of toxohormone was readily inactivated by heating at 100 degrees C or treatment with trypsin, but not by DNase and RNase treatment.
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PMID:Immunosuppression induced by "toxohormone" from mouse tumor cells in culture. 49 45

The effect of immune RNA treatment on the incidence of death from pulmonary metastases was studied in C57BL/6J mice after excision of a B16 murine melanoma. Immune RNA was extracted from the lymphoid tissues of guinea pigs immunized with B16 tumor and then incubated in vitro with normal C57BL/6J mouse splenocytes. Mice receiving intraperitoneal injections of these RNA-treated syngeneic splenocytes after the primary B16 isograft was resectioned showed significantly improved long-term survival (42 to 67 percent in three successive experiments) as compared to control mice (0 to 20 percent survival) receiving untreated splenocytes. The effect of RNA treatment was tumor-specific and ribonuclease sensitive. The results suggest that immunotherapy with immune RNA may be of benefit to certain patients after surgery for cancer.
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PMID:Prevention of death from metastases by immune RNA therapy. 69 19

A review of the literature and current biochemical studies is presented which provides significant evidence of alteration in the level of the enzyme ribonuclease activity in cancer. Current studies reveal that 80% of all cancer patients have alteration in ribonuclease activity and that individuals known to be at high risk for the development of cancer also demonstrate significant alteration of ribonuclease activity. It is noted that while elevation of serum ribonuclease exists within the cancer state and appears to be independent of clinical status (relapse, remission, or cured), diminished activity is found within the tumor itself. Animal models are reviewed which demonstrate that ribonuclease activity becomes elevated in the murine species subsequent to the transplantation of tumor and following the infection of the host with oncogenic virus. The occurrence of elevated ribonuclease activity in high tumor incidence strain mice long before the development of overt tumor is alos discussed. To date it is not possible to assign a specific function to the changes in the level of ribonuclease in connection with the cancer state. However, evidence indicating that tumor chemotherapy is generally associated with early elevation of ribonuclease activity within the tumor cell suggests that increased ribonuclease activity may play a role in the process by which the host restricts neoplastic transformation. The potential of this enzyme as a biochemical marker in cancer is discussed.
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PMID:Alteration of human serum ribonuclease activity in malignancy. 75 46

An ovarian cystadenocarcinoma-associated antigen (OCAA) was found to be common to all serous and mucinous cystadenocarcinomas of the ovary. It was apparently absent in tissues of normal reproductive organs. Furthermore, OCAA was not detected in benign ovarian serous and mucinous cyst-adenomas or in any other gynecologic or nongynecologic cancers thus far tested. The antigenic determinant of OCAA was immunologically unrelated to the carcinoembryonic antigen, other known tumor antigens, or the histocompatibility antigens. We purified and partially characterized OCAA. The antigen was a high-molecular-weight glycoprotein soluble in 0.6 M perchloric acid. It consisted of about 50-60% protein (based on dry wt). Amino acid composition in OCAA was characterized by a high percentage of threonine, serine, proline, and valine. Galactose and N-acetylglucosamine were the principal carbohydrate constituents. The antigenic activity was resistant to treatment with trypsin and protease and also to treatment with DNase, RNase, and N-acetylneuraminidase. The antigenicity was considerably reduced by mild periodate oxidation.
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PMID:Tumor-associated antigen for cystadenocarcinomas of the ovary. 82 81

The antitumor effect of reserve polysaccharide, paramylon, from Euglena gracilis on the transplantable sarcoma-180 was examined in mice. This polysaccharide had an effect similar to that of lentinan. Paramylon, in a dose of 1 mug/g body weight, injected intraperitoneally 24 hr after tumor implantation had an inhibitory effect on the tumor growth, although without causing complete regression of the tumor. Alkaline-treated paramylon had a similar effect but at a smaller concentration than the native one. The inhibitory activity was not lost when the paramylon preparation was treated with pronase, DNase, or RNase. The antitumor effect might be a lymphocyte-mediated process. In tumors that were regressing after treatment, there was extensive outpouring of lymphoid cells with plasma cells and macrophages. A test conducted using paramylon ruled out the possibility of an interferon-mediated inhibiotry effect on tumor growth.
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PMID:Antitumor activity of paramylon on sarcoma-180 in mice. 82 42

Serum RNase levels were measured in 34 patients with multiple myeloma and compared with 51 normal controls and 28 non-myeloma patients on chronic hemodialysis. Nineteen of the myeloma patinets with creatinine clearance (CCr) greater than 50 ml/minute had mean serum RNase levels that were statistically indistinguishable from those of the normal controls. The 15 myeloma patinets with CCr less than 50 ml/minute had mean RNase levels much higher than normal controls or myeloma patients with normal renal function. Patients without myeloma but on hemodialysis for chronic renal failure of varied etiologies had markedly elevated serum RNase levels. A strong correlation between RNase levels and renal insufficiency, as measured by CCr, has thus been demonstrated. In addition, case histories of 5 representative myeloma patients were analyzed in greater detail; they illustrated the rise and fall of RNase levels as a function of the status of their renal insufficiency, regardless of the extent of the underlying myeloma. We concluded that the serum RNase level was an indicator of renal function, and was not a biomarker either for the presence or extent of the plasma cell tumor.
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PMID:Influence of renal insufficiency on levels of serum ribonuclease in patients with multiple myeloma. 84 91

We have investigated the pathogenesis of the polyclonal hypogammaglobulinemia associated with BALB/c plasmacytomas TEPC-183 and SPQC-11 to gain insight into the hypogammaglobulinemia observed in human myeloma. With pokeweed mitogen-driven IgM biosynthesis by mouse splenocytes as the indicator system for suppression, we found that a protein extract of asscites cells obtained from these tumor-bearing animals could suppress immunoglobulin production, whereas like extracts from a non-suppressing plasmacytoma, modified RPC-5, caused no suppression in vitro. Extracts of tumor ascites depleted of mononuclear phagocytes by iron carbonyl treatment showed little suppressor activity. The active extract was not cytotoxic and contained no mycoplasma or common murine viruses. Furthermore, the active suppressor factor appears to be a low m.w. protein that is not affected by treatment with ribonuclease. These results and others are consistent with the idea that the hypogammaglobulinemia of myeloma is due to the formation of immunoregulatory macrophage-like cells which synthesize a suppressor substance.
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PMID:Hypogammaglobulinemia in experimental myeloma: the role of suppressor factors from mononuclear phagocytes. 85 68


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