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)

Cultures of Rous sarcoma virus-transformed chick embryo fibroblasts (RSVCEF) produce 50-fold more of the protease plasminogen activator (PA), than do normal chick embryo fibroblasts. Treatment of RSVCEF cultures with the tumor promoter phorbol myristate acetate (PMA) further enhances (8- to 12-fold) the level of PA activity. Increased levels of PA activity in RSVCEF are observed as early as 1 to 2 hr after PMA treatment. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrates that the PA produced by PMA-treated cultures has a molecular weight identical to that of the PA produced by untreated cultures. PA induction by PMA cannot be accomplished in cell-free extracts, but requires protein synthesis in intact cells. Under serum-free conditions, PMA-treated RSVCEF secrete high levels of PA for 4 to 6 days and undergo pronounced morphological alterations. Modified culture conditions and the use of PMA to induce PA has allowed for the accumulation of large amounts of RSVCEF culture fluid and the subsequent purification of the enzyme. The sensitivity of transformed CEF to PMA and the generation of enhanced proteolytic activity in the cellular microenvironment may provide a model system to examine the role of both PA in malignant transformation and PMA in tumor promotion.
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PMID:Synergistic effect of tumor virus transformation and tumor promoter treatment on the production of plasminogen activator by chick embryo fibroblasts. 21 28

Sera of patients with various malignancies are known to contain DNA-binding proteins (DBP) which are not present in sera of normal individuals. In this paper sera of patients with malignant melanoma (MM) were examined as to whether characteristic DBP are present, too. DBP are isolated by DNA-affinity chromatography and represent 0.5-0.9% of all serum proteins. After separation of the DBP by SDS slab gel electrophoresis no typical DBP is detectable in sera of MM-patients. However, quantitative differences are found in sera of patients in the clinical stages I-III and/or tumor level 3-5: 1. All 9 sera of patients who had clinical signs of MM contain more DBP with molecular weight (mw) of 20,000-24,000 dalton than control sera. However, these DBP are only increased in 30% of the 22 sera from MM-patients who had clinical signs for 13-73 months after tumor excision. 2. All sera of the 10 MM-patients of whom sera were drawn twice after tumor excision at an interval of 7-46 months without clinical signs, showed a reduction of DBP with mw 30,000, 68,000, and 165,000.
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PMID:DNA-binding proteins in the sera of patients with malignant melanoma. 22 3

We have quantitated the transformation-sensitive, cell surface LETS glycoprotein on many untransformed cell types. By SDS-polyacrylamide gel electrophoresis, this trypsin-sensitive iodinatable glycoprotein comprises 1-3% of total cellular protein of the seven early passage cell types tested. In contrast, it constitutes less than 0.15% of the protein in four of six continuous cell lines. This decrease is reflected in alterations both in [14C]glucosamine labeling and in the immunofluorescent staining of early passage vs. these four permanent cell lines. These results help to clarify previous experiments in which CSP, a purified LETS protein, partially restored a fibroblastic phenotype to cells transformed by tumor viruses. These findings also indicate that a major decrease in this cell surface glycoprotein can occur in the establishment of a continuous cell line without resulting in cellular transformation.
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PMID:Quantitation of a transformation-sensitive, adhesive cell surface glycoprotein. Decrease of several untransformed permanent cell lines. 32 19

Immunological and chemical studies of cell surfaces from normal and transformed BALB/c fibroblasts have shown alterations associated with transformation. The cells studied include normal lines which do not cause tumors when injected into BALB/c mice, viral transformants, and spontaneous transformants which cause tumors that either regress or grow progressively, killing the host. The spontaneously transformed progressors include cell lines which are immunogenic and nonimmunogenic as determined by the ability of tumor excision to protect an animal from subsequent rechallenge by tumor cells. Tumor-bearing mice produce lymphocytes which are nonspecifically cytotoxic for all the normal and transformed lines. Some of the cell lines induce specific antibody formation in BALB/hosts. Antisera have been prepared in rabbits which are specific for the transformed cell lines. These antisera can be used to determine specific surface changes on the transformed cells. Chemical studies have shown glycolipid alterations between the normal cells and some, but not all, of the transformants. Glycoproteins labeled by lactoperoxidase-125I or [3H] glucosamine were compared by SDS gel electrophoresis. Results from these studies do not show changes associated with malignancy. Individual glycoprotein regions from gels were treated with pronase, and the glycopeptides compared by Sephadex G50 chromatography. Alterations in glycopeptides from several cellular glycoproteins are the only changes which appear to be associated with malignancy.
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PMID:Chemical and immunological studies of cell surfaces from normal and transformed cells. 33 94

Plasma membrane preparations were obtained from solid lymphosarcomas and fibrosarcomas by disrupting the tissues with a mechanical press. The subcellular fractions were isolated by differential centrifugations and examined by electron microscopy. The membrane-enriched fractions were also assayed for protein content and analyzed in SDS-polyacrylamide gel electrophoresis; a fairly good reproducibiltiy was found comparing different membrane preparations derived from the same tumor. The H-2 antigenic activity of the different membrane preparations was demonstrated in vitro by the inhibition of the C'-dependent 51Cr-release assay using monospecific H-2 alloantisera. The specificity of the assay was ascertained by the lack of inhibition of unrelated monospecific H-2 alloantisera and by a dose-response relationship between the amount of added membranes and the observed inhibition. The immunogenicity of the membranes was assessed in vivo by immunizing allogeneic mice that developed anti-H-2 alloantibodies. The possible mechanisms of the tissue disruption by the press are also discussed.
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PMID:Preparation of antigenically active membranes from solid murine lymphomas and fibrosarcomas. 37 32

Ehrlich ascites tumor cell extracts form a gel when warmed to 25 degrees C at pH 7.0 in sucrose solution, and the gel rapidly becomes a sol when cooled to 0 degrees C. This gel-sol transformation was studied quantitatively by determining the volume or the total protein of pellets of gel obtained by low-speed centrifugation. The gelation depended on nucleotide triphosphates, Mg2+, KCl, and a reducing agent. Gelation was inhibited reversibly by 0.5 microM free Ca2+, and 25--50 ng/ml of either cytochalasin B or D, but it was not affected by 10 mM colchicine. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated that the gel was composed of six major proteins with mol wt greater than 300,000, 270,000, 89,000, 51,000, 48,000, and 42,000 daltons. The last component was identified as cell actin because it had the same molecular weight as muscle actin and bound with muscle myosin and tropomyosin. The role of actin in gelation was studied by use of actin-inhibitors. Gelation was inhibited by a chemically modified subfragment-1 of myosin, which binds with F-actin even in the presence of ATP, and by bovine pancreatic DNase I, which tightly binds with G-actin. Muscle G-actin neutralized the inhibitory effect of DNase I when added at an equimolar ratio to the latter, and it also restored gelation after its inhibition by DNase I. These findings suggest that gelation depends on actin. However, the extracts showed temperature-dependent, cytochalasin-sensitive, and Ca2+-regulated gelation as did the original extracts when the cell actin in the extracts was replaced by muscle actin, suggesting that components other than cell actin might be responsible for these characteristics of the gelation.
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PMID:The role of actin in temperature-dependent gel-sol transformation of extracts of Ehrlich ascites tumor cells. 45 53

Carcinoembryonic actigen (CEA) was purified from three liver metastases of carcinoma recti by a conventional procedure involving perchloric acid extraction of tumor tissue and fractionation of the extract by gel filtrations on Sepharose 4B and Sephadex G-200. The preparations obtained showed a different degree of heterogeneity in SDS-polyacrylamide gel electrophoresis and crossed immunoelectrophoresis, and also a different antigenic activity. One of preparations obtained was a homogeneous CEA by all these criteria, and two others showed heterogeneity and lower antigenic activity. The most heterogeneous CEA preparation was further purified by the affinity chromatography on Concanavalin A-Sepharose 4B and by DEAE-Sephadex A-50 chromatography and the usefulness of these procedures for purification of CEA is compared.
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PMID:Differences in the purification effect of carcinoembryonic antigen (CEA) from the three different hepatic metastases of rectum carcinoma. 47 Nov 22

The nature of collagen from 2 cases of dermatofibrosarcoma protuberans was studied. For this purpose, the tumor tissue was carefully separated from adjacent normal dermis. The collagen types comprised in the tumor were identified by CM-cellulose chromatographic and SDS-gel electrophoretic analysis of the component alpha-chains. Semiquantitative evaluation of the relative type III content was established by separation of the cyanogen bromide peptides on gels of 12% polyacrylamide in SDS. These studies showed that dermatofibrosarcoma protuberans contains alpha 1(I)-, alpha 2-, and alpha 1(III)-chains as well, and corresponding type I- and type III-related CNBr peptides. Comparing the collagen from dermatofibrosarcoma protuberans to that of normal skin, the relatively increased type III content in the case of dermatofibrosarcoma protuberans becomes apparent.
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PMID:Nature of collagen in dermatofibrosarcoma protuberans. 47 45

We have studied the polypeptides associated with the expression of the transforming region of the Ad5 genome by immunoprecipitating antigens (using the double antibody and protein A-Sepharose techniques) from cells infected with wild-type (wt) Ad5 or transformation-defective host range (hr) mutants and from cells transformed by Ad5. Three different antisera were used: P antiserum specific for early viral products (Russell et al., 1967) and two different hamster tumor antisera. Immunoprecipitation of antigens from wt-infected KB cells followed by SDS-polyacrylamide gel electrophoresis of precipitated proteins revealed that a major polypeptide having a molecular weight of approximately 58,000 was detected with all three antisera and with both the double antibody and the protein A-Sepharose techniques, while P antiserum also precipitated polypeptides of molecular weights 72,000, 67,000 and 44,000, which probably represent the DNA binding protein and related polypeptides, respectively. With the double antibody technique, in addition to the proteins mentioned above, P antiserum and the hamster tumor antisera precipitated a 10,500 dalton polypeptide which was not detected when the protein A-Sepharose procedure was used. Using either the double antibody or the protein A-Sepharose technique, we found that hr mutants from complementation group II failed to induce the synthesis of the 58,000 dalton protein, whereas mutants from complementation group I produced normal or near normal amounts. Using the double antibody technique, we found that the 10,500 dalton protein was absent or made in reduced amounts by group I mutants. A 58,000 dalton protein was detected in a number of different Ad5-transformed cell lines, including the 293 human line, the 14b hamster line and several transformed rat cell lines. This observation and the fact that transformation negative group II mutants fail to induce the synthesis of a 58,000 dalton polypeptide suggest that this protein is one of the Ad5-specific products necessary for cell transformation.
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PMID:Tumor antigens of human Ad5 in transformed cells and in cells infected with transformation-defective host-range mutants. 51 55

Tumor-associated surface antigens (TASA) on a Moloney leukemia virus (M-MuLV)-induced lymphoma, MBL-2, in C57BL/6 mice (B6) were characterized. The surface proteins of MBL-2 cells were selectively radioiodinated and then extracted by Nonidet P40. The solubilized materials were then reacted with a variety of antisera: monospecific antisera to murine leukemia viral proteins (anti-gp69/71, anti-p30, anti-p15, anti-p12 and anti-p10), sera from B6 which regressed murine sarcoma tumors induced by murine sarcoma virus (anti-MSV) and a rabbit anti-MBL-2 antiserum. The resulting radioimmune precipitates were analyzed and compared in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The following results were obtained. (1) Among all anti-viral protein antisera tested only anti-gp69/71 was active and detected a protein doublet of gp69/71 and its degradation fragments of 42,000 and 35,000 daltons. (2) Radioimmune precipitates prepared with anti-MSV showed a SDS-PAGE pattern similar to that seen with anti-gp69/71. This result indicated that the surface antigen detected by the anti-MSV serum on MBL-2 tumor cell was probably a viral envelope antigen. (3) The rabbit anti-MBL-2 serum detected on the cell membrane an antigen of approximately 95,000 daltons which was tumor-associated and did not appear to be related to virion components. The anti-MBL-2-serum still reacted with the 95,000 dalton antigen after absorption with disrupted M-MuLV virus and with gp69/71 and p30 purified from the virus.
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PMID:Immunochemical characterization of tumor-associated surface antigens on a Moloney leukemia virus-lymphoma, MBL-2. 52 73


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