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)

DNA-dependent RNA polymerases from nuclei of T8 Guerin tumor were studied. Two enzymes were purified several hundred times by the use of ammonium sulfate precipitation, DEAE-cellulose and phosphocellulose chromatography. One of them belongs to A(I) RNA polymerases and the second to B(II) as was established from their metal and ionic strength requirements. activity in the presence of native and denatured DNA and the resistance to a-amanitin inhibition. The quantity of class A enzyme was increased compared to B, a fact observed with most neoplastic tissues so far studied. This increase of the polymerase responsible for ribosomal RNA synthesis could probably be related to malignant transformation in animals.
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PMID:DNA-dependent RNA polymerase from T8 Guerin tumor. 56 23

Hypertonic salt extracts (3 M KCl) of x-irradiation-induced Holtzman rat small bowel adenocarcinomas blocked the in vitro destruction of allogeneic cultured cells of this malignancy by sensitized lymphoid cells obtained from tumor-bearing animals. The protective effect were mediated by a blocking action at both the effector and the target cell level. The extracts were separated into 50% ammonium sulfate soluble and insoluble fractions with the soluble fraction being more effective in blocking the cytotoxic responses through interaction with the lymphoid cells whereas the insoluble one had a greater effect upon tumor target cells. Associated with both fractions was the oncofetal glycoprotein previously identified with the cellular membrane of this x-ray-induced malignancy. Immunoglobulins were identified with insoluble fraction; some were able to bind the oncofetal protein, thus clasifying it as a fetal antigen. The protective effects of the soluble fraction and this neoantigen were found to be citric acid labile, whereas the effects due to the insoluble fraction were unchanged.
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PMID:Lymphocyte cytotoxicity in x-irradiation-induced rat small bowel adenocarcinoma. III. Blocking by 3 M KCL extract. 62 24

Soluble murine melanoma-associated antigens (MAA), partially purified from the media of B16 melanoma cells in culture by ammonium sulfate precipitation and Sephadex G-200 chromatography, were tested for their effect on tumor growth. MAA were immunogenic in syngenic mice as evidenced by their ability to induce anti-melanoma antibodies and partial protective tumor immunity. The level of immunity was variable. It ranged from retardation of tumor development to almost complete suppression of tumor growth. The results were influenced by the nature of the control group, since immunization to either normal tissue antigens or complete Freund's adjuvant enhanced tumor growth. Overall, 46 of 91 MAA immunized mice, but none of 114 control mice, survived over 6 weeks (p less than 0.001). The protective immunity was specific since MAA immunized mice were not resistant to challenge with an unrelated syngeneic tumor (BW 10232 ADENOCARCINOMA). Partially purified normal tissue antigens were also immunogenic in syngeneic mice. They induced low levels of antibodies to, and enhanced the growth of, melanoma. These findings indicate that the culture media of melanoma cells contains tumor antigens that retain their biologic activity after partial purification, and that can induce specific, although only partial, protective immunity to melanoma.
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PMID:Antibody response and tumor growth in syngeneic mice immunized to partially purified B16 melanoma-associated antigens. 62 29

Ricinus communis L., usually cultivated for production of oil, has some use in medicine, cosmetic industries and as motor oil. The defatted seed meal is very toxic, and can not be used as human or animal food. This study undertook extraction and identification of ricin, a toxalbumine, from Iranian Ricinus communis L. Ricin, was extracted from the seeds using dilute acid solution, salted out with ammonium sulfate, and purified by Sephadex G - 75 and DEAE - cellulose column chromatography. Disc electrophoresis showed the degree of the purification. Ricin is an anti-tumor and allergenic compound. It is also useful in biochemical research in gene control and protein systhesis.
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PMID:Extraction and partial purification of ricin from Ricinus communis L. 65 82

A partially purified enterotoxin was obtained from the growth medium of Escherichia coli strain 711 (P307), a derivative of E. coli K-12, by ultrafiltration, precipitation with ammonium sulfate, molecular sieving, and anion exchange column chromatography. The active moiety, which is heat-labile, behaved like a protein particle of 180,000 to 200,000 daltons during molecular sieving and ultracentrifugation. During polyacrylamide gel electrophoresis in sodium dodecyl sulfate (SDS-PAGE), it dissociated into two subunits with apparent molecular weights of 68,000 to 70,000 and 14,000 to 15,000. SDS-PAGE after heating in SDS changed the larger subunit to an apparent molecular weight of about 40,000; the smaller subunit did not change. The intact particle induced rounding of the cells in Y-1 mouse adrenal tumor cells used for assay. The detergent-dissociated molecules were not active. Proteolysis of the purified toxin by tolylsulfonyl phenylalanyl chloromethyl ketone-trypsin appeared to enhance its activity. The addition of serum to the assay medium resulted in partial depression of the activity. Activity was also abolished by preincubation of the toxin with either a rabbit antiserum to it or solutions containing GM1 ganglioside. The length of time needed to evoke a response in the assay system by fractions from different stages in the purification of the enterotoxin was a useful parameter in the evaluation of specific activity.
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PMID:Partial purification and characterization of a heat-labile enterotoxin of Escherichia coli. 78 81

A chimpanzee anti-human melanoma antiserum was used to study the enzymatic susceptibility and spontaneous release into tissue culture medium of human melanoma tumor-associated antigens (TAA). Limited proteolytic digestion of melanoma cells with trypsin or with pronase rendered these cells refractory to lysis by the chimpanzee antiserum and complement. Longer periods of incubation of higher concentrations of enzyme caused an increased sensitivity to lysis. Digestion of melanoma cells with neuraminidase apparently exposed antigens reactive with natural antibodies in rabbit complement because cells so treated had a marked increase in sensitivity to cytolysis. Absorption of the complement with either neuraminidase-treated human melanoma cells or washed human spleen cells prior to its use in the cytotoxicity assay removed this activity. When absorbed complement was used, neuraminidase had no noticeable effect on the expression of malanoma TAA. These results suggest that proteolytic digestion of melanoma cells may prove to be a useful means of solubilizing TAA. The spontaneous release of melanoma cell membrane TAA was studied. Protein precipitated by (NH4)2SO4 from four of six samples of tissue culture medium used to feed malanoma cell lines contained significant antigenic activity compared to a control "antigen" preparation, whereas one preparation contained only limited TAA activity. One melanoma cell line that apparently failed to release TAA into the culture medium had previously become nonreactive with the chimpanzee antiserum. From these data, we conclude that melanoma cells growing in tissue culture rapidly release large amounts of TAA into the culture media and, as a result, the spent culture medium may be a good source for obtaining TAA for further study. The significance of these results is discussed.
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PMID:Enzymatic susceptibility and spontaneous release of human melanoma tumor-associated antigens. 83 72

An anti-neoplastic protein was isolated from the endosperm of the seeds of Caesalpinia gilliesii by extraction with water, dialysis and precipitation by ammonium sulfate or acidification. The precipitated protein mixture was separated by column chromatography into three principal proteins, one of which, termed cesalin, inhibited the growth of Walker 256 carcinosarcoma. There is an associated carbohydrate with the cesalin that can be largely removed by chromatography on hydroxyl apatite; the remaining carbohydrate (about 0.3%) is a hexosan. Cesalin, molecular weight 110,000, migrates as a single component by polyacrylamide gel electrophoresis at pH 8.3, but in a denaturing system containing sodium dodecyl sulfate three bands were observed. The correspond to protein sub-units of approximately 30,000 daltons. Anti-tumor tests in rats showed 70-80% inhibition of Walker 256 growth at a dose of 80 microgram/kg/day of cesalin.
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PMID:Cesalin--an anti-neoplastic protein. 89 84

Yeast phenylalanine ammonia-lyase (EC 4.3.1.5) catalyzes the deamination of L-phenylalanine to form trans-cinnamic acid and tyrosine to trans-coumaric acid. Maximal enzyme activity in Rhodotorula glutinis (2 units/g, wet weight, of yeast) was induced in late-log phase (12 to 14 hours) of growth in a culture medium containing 1.0% malt extract, 0.1% yeast extract, and 0.1% L-phenylalanine. A highly purified enzyme was obtained by fractionation with ammonium sulfate and sodium citrate followed by chromatography on DEAE-cellulose and Sephadex G-200. The active preparation yielded a major component on three different polyacrylamide gel electrophoretic systems. Antisera to phenylalanine ammonia-lyase was raised in rabbits and detected by double immunodiffusion. The antigen-antibody complex was enzymatically active in vitro. The biological half-life of the enzyme was approximately 21 hours in several mammalian species (mice without and with BW10232 adenocarcinoma and B16 melanoma, rats, and monkeys) after a single injection; however, upon repeated administration, phenylalanine ammonia-lyase had a much shorter biological half-life. The onset of rapid clearance occurred earlier in tumor-bearing than in nontumor-bearing mice indicating a direct or indirect influence by the tumor on the biological half-life of phenylalanine ammonia-lyase.
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PMID:Phenylalanine ammonia-lyase. Induction and purification from yeast and clearance in mammals. 98 16

Two different forms of DNA-dependent RNA polymerase have been solubilized and purified from nuclei of Ehrlich ascites tumor cells. The purification procedure involves ammonium sulfate precipitation and gel filtration on Sephadex G-25. The separation of A and B activities is achieved by chromatography on DEAE-cellulose. Nuclei are prepared from cells, sensitive or resistant to daunorubicin. RNA polymerases A and B have an absolute requirement of divalent cations for activity. Native DNAs are better templates than heat-denatured DNAs for RNA polymerase A. On the contrary heat-denatured DNA is more transcribed than the native one by RNA polymerase B. The low level of transcription of total and nucleolar ascites DNAs is due to the DNA, the same results being obtained with ascites and calf thymus RNA polymerases A and B. The inhibitory action of daunorubicin on RNA polymerases A and B from Ehrlich ascites tumor cells has been studied in vitro. The same results are obtained with enzymes extracted from sensitive or resistant cells. Daunorubicin does not inhibit the binding of RNA polymerases to the DNA template, but prevents the transformation of the DNA-daunorubicin-RNA-polymerase unstable complex into the highly stable one. This inactive ternary complex has a dissociation rate faster than the stable complex formed without daunorubicin. The size of the RNA synthesized in the presence or absence of daunorubicin is the same.
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PMID:Daunorubicin inhibition of DNA-dependent RNA polymerases from Ehrlich ascites tumor cells. 99 57

Considerable skin-reactive and macrophage-disappearance-inducing activities were detected in cell-free fluids of 2 mouse ascites tumors (Ehrlich ascites tumor, leukemia L 1210). Fractionation of the supernatants by ammonium sulfate precipitation, gel filtration on Sephadex G-200, and DEAE-Sephadex A-50 column chromatography resulted in characterization of the proteinaceous substance which accounts for skin-reactive activity. The factor responsible bears a close physicochemical and biological resemblance to the skin-reactive factor of lymphocytic origin which is known to be generated by specific or nonspecific stimulation of lymphocytes in vitro, or to be produced spontaneously by lymphoblastoid cell lines. The biological significance of the findings is discussed.
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PMID:Presence and characterization of lymphokines in mouse ascites tumor fluids. 100 14


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