Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0006826 (cancer)
 1,092,456 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The distribution of the viral glycoprotein, gp 69/71, was studied on the cell surfaces of virus-producing and nonproducing cells. gp 69/71 was distributed evenly on cell membranes and on viral membranes of cells producing murine leukemia virus. gp 69/71 was distributed uniformly on cell membranes of thymocytes from NZB and strain 129 mice but was not detected on cell membranes of BALB/c thymocytes. Viral particles were associated with NZB and BALB/c thymocytes but were not in or on 129 thymocytes. We conclude that the presence of gp 69/71 on thymocyte membranes is not related to virus production. In the strains showing gp 69/71 on their thymocyte surfaces (NZB and 129), a large percentage of the thymocytes are positively labeled, all more or less equally. Immunochemical analysis of cell surface proteins labeled with 125I corroborated the ultrastructural observations. Thus, gp 69/71 can be expressed on the surface of thymocytes independently of virus particle production.
Cancer Res 1976 Jan
PMID:Distribution of viral glycoprotein gp 69/71 on cell surfaces of producer and nonproducer cells. 17 7

It was previously shown that the fibroblast surface antigen (SF antigen, SFA) is composed of polypeptides of high molecular weight 210,000 (SF210) and 145,000 (SF145) and that both of these decrease in quantity after transformation of the fibroblasts by Rous sarcoma virus (RSV). The present experiments show that SF210 is a glycoprotein. It is accessible to surface labelling by lactoperoxidase catalyzed iodination. The SF210 molecule is highly susceptible to trypsin on cell surface. Anti-SFA antibodies specifically precipitated the surface labelled polypeptide. The lactoperoxidase iodinated SF210 polypeptide was greatly reduced in cells transformed by RSV. It is concluded from these studies that the large external transformation sensitive (LETS) protein detected by other workers is the same molecule as SF210. Part of the label of surface iodinated fibroblasts did not enter the polyacrylamide gels. This high molecular weight material is also susceptible to trypsin treatment and decreases in quantity after transformation by RSV. The data suggest that it may be antigenically related to SF protein. Treatment of surface of 35S-methionine-labelled cultures with trypsin in concentrations able to initiate proliferation of density-inhibited cells rapidly released SF210 from fibroblast surface. A single high molecular weight polypeptide (mol. wt about 200,000, SF200) was detected in the culture medium. SF210 may thus be a major target molecule of trypsin action. Treatment of cultures with insulin that also stimulated the fibroblasts to initiate proliferation did not result in any detectable alteration in the external glycoprotein SF210. It is concluded that although release of SF210 may be a sufficient trigger to stimulate proliferation in stationary cells, this molecule appears not to be directly involved in initiation of fibroblast proliferation from the G1 (or G0) phase of the cell cycle.
Int J Cancer 1976 Feb 15
PMID:Fibroblast surface antigen (SF): the external glycoprotein lost in proteolytic stimulation and maligant transfromation. 17 31

Two principal virus-directed antigens have been identified on the surface of oncornavirus-infected chick embryo cells. One is identical with the major virus type-specific envelope antigen, which is a glycoprotein with a molecular weight of 85,000. The 2nd antigen (tumor-specific cell surface antigen) is specific for transformed cells, i.e., absent from productively infected but nontransformed cells. This antigen has been identified as a glycoprotein with a molecular weight of 100,000 and was not found in the mature virion. Remarkably, both antigens induce humoral as well as cellular immunity in the chicken. It could be shown that cells can be killed in cytotoxic assays via either the tumor-specific cell surface antigen or the virus envelope glycoprotein alone.
Cancer Res 1976 Feb
PMID:Immune response to oncornaviruses and tumor-associated antigens in the chicken. 17 20

Fibroblasts derived from individuals with mucopolysaccharidosis, an inborn error of metabolism, have been found to be more easily transformed by simian virus 40 than are cells derived from normal individuals. The increased susceptibility does not seem to depend upon changes in glycoprotein at the cell surface. Repeated observations were necessary to demonstrate these differences, and we do not believe that this test is suitable for routine screening for cancer susceptibility.
Cancer Res 1976 Feb
PMID:The transformation by simian virus 40 of cells from patients with mucopolysaccharidosis and from normal controls. 17 92

Cell membranes from mouse L-cells (L-B82), rat hepatoma (HTC-H1), and three clones of their somatic cell hybrids (07, V4a, and V5) showing different degrees of density-dependent inhibition of growth were analyzed by polyacrylamide gel electrophoresis. The membrane polypeptides of the hybrid clones were all similar and all showed higher proportions of polypeptides with molecular weights of 56,000 and 45,000 than their parents of their normal counterparts. The major glycoprotein form cell hybrids appeared to be identical with that of rat liver or rat hepatoma cells and different from that of L-cells. One hybrid showed density-dependent inhibition growth; the other two, like both parents, did not. All produced tumors in nude mice, although tumor production by the hybrids was delayed. A large external protein (M.W. 240,000) iodinated by lactoperoxidase-catalyzed reaction was virtually missing in the parents but was present at high levels in all their hybrid clones. Thus, there was a lack of correlation between the presence of this protein, growth control in vitro, and tumorigenicity. Furthermore, no correlation was seen between agglutination of these cells by concanavalin A and tumorigenicity. The factors controlling these membrane properties thus are independent of density-dependent inhibition of growth and of those controlling the expression of cancer.
Cancer Res 1976 Aug
PMID:Characteristics of cell membranes from somatic cell hybrids between rat hepatoma and mouse L-cells. 17 11

Rat ascites hepatoma AH109A cells (present as a free form in vivo) can aggregate and then develop well-defined tripartite junctional complexes, including intermediate junctions, desmosomes and focal tight junctions, on incubation with a glycoprotein separated from rat ascites hepatoma AH136B cells (forming cell islnds in vivo). The development of binding structures was strongly inhibited by actinomycin D. AH109A cells or rat ascites hepatoma YS cells (present as a free form in vivo) previously treated with the glycoprotein for 24 h, when inoculated i.p., proliferated as free cells in the ascitic fluid, like the untreated cells. AH109A cells actively proliferating in the skin do not form any junctional complexes. The reason for the failure of island formation by AH109A cells or YS cells in vivo is discussed.
Br J Cancer 1976 Oct
PMID:The induction of tumour cell adhesiveness and intercellular junctions by a glycoprotein of rat ascites hepatoma cell surface. 18 12

Previous studies suggested that immunogenic breast cancer tissues contained a component(s) that is antigenically similar to some component of murine mammary tumor virus (MuMTV) and resembles the glycoprotein, M.W. 55,000 (gp55), of RIII-MuMTV in molecular weight and charge density. This investigation measured in vitro cellular hypersensitivity responses of breast cancer patients to RIII mouse milk, purified RIII-gp55, C3H-MuMTV, autologous and homologous breast cancer tissues, gp50 of A-MuMTV, and preparations of Rauscher leukemia virus and Mason-Pfizer monkey virus. Particular attention was paid to cross-reactivity between gp55 and the other targets. The data indicate that responsiveness to C3H-MuMTV and RIII milk are linearly correlated with responsiveness to gp55. A preferential relationship was demonstrable between responses to gp55 and to those breast cancer tissues containing a gp55-like protein component (S-p50). The critical role of a gp55-like protein as the antigen responded to by breast cancer patients' in leukocytes was also suggested by the ability of anti-gp55 antiserum to decrease leukocyte responsiveness to RIII-gp55, C3H-MuMTV, and breast cancer tissues. In vitro cellular hypersensitivity against RIII-gp55 was preferentially found in prognostically favorable cases with immunogenic lesions. Further studies are needed to test the possibility that gp55 might be of value in the immunodiagnosis of early breast cancer, the monitoring of prognostically significant cellular hypersensitivity, and the induction of such hypersensitivity (immunoprophylaxis).
Cancer Res 1976 Nov
PMID:Cellular hypersensitivity of gp55 of RIII-murine mammary tumor virus and gp55-like protein of human breast cancers. 18 25

The plasma membrane proteins of lymphocyte populations from normal outbred Syrian hamsters were compared with those of a neoplastic transformant line (GD 248) induced by simian virus 40. Both quantitative and qualitative differences were observed. Gradient dodecyl sulfate-polyacrylamide gel electrophoresis revealed 12 major protein components in the membranes of both cell populations. Both membrane categories also contained small amounts of immunoglobulin. Compared with the membranes of the reference cell population, GD 248 membranes showed a 60% decrease of approximately 210,000 daltons of glycoprotein; a 10% reduction of about a 48,000-dalton band and virtually complete loss of a 15,000-dalton component concomitant with a 57% increase in a 52,000-dalton band; fusion to two subcomponents (mol wt approximately 250,000 daltons); and emergence of approximately 120,000 and 30,000 daltons glycoproteins. In addition, the relative mobility of an approximately 95,000-dalton component increased by roughly 0.02 U. Crossed immune electrophoresis in Trition X-100 with heterologous antiserum against GD 248 microsomal membranes revealed both a new component with a high level of electrophoretic mobility and intensification and additional heterogeneity in a strongly antigenic component with a low level of electrophoretic mobility. Crossed-line immune electrophoresis indicated that at least two antigens in the membranes of GD 248 cells lacked the membranes of the reference cell population.
J Natl Cancer Inst 1976 Nov
PMID:Membranes of normal hamster lymphocytes and lymphoid cells neoplastically transformed by simian virus 40. II. Plasma membrane proteins analyzed by dodecyl sulfate-polyacrylamide gel electrophoresis and two-dimensional immune electrophoresis. 18 93

Ten post-weanling 4-month-old cats, designated "tracers", were placed in a feline leukemia cluster household to determine the efficiency of horizontal transmission of feline leukemia virus (FeLV). The tracer cats were confirmed as negative for prior exposure to FeLV. Following the placement in the leukemia cluster environment, the tracer cats were serologically monitored at intervals of 3-6 weeks for a total period of 1 year. The tests employed included the detection of FeLV using fixed-cell immunofluorescence and the detection and titration of antibody to : (1) the feline oncornavirus-associated cell membrane antigen (FOCMA), as detected by membrane immunofluorescence; (2) viable FeLV, using serum neutralization; (3) virion core protein p30, using radioimmunoprecipitation; and (4) virion glycoprotein gp70, using radioimmunoprecipitation. All of the tracers had evidence of horizontal infection by FeLV, by several criteria. Seven of the 10 had virus that could be isolated from plasma. All of these 7 developed a terminal illness within 18 months; 3 developed aplastic anemia, 3 infectious peritonitis, and 1 lymphoma. The remaining 3 were negative for FeLV by both virus isolation and fixed-cell immunofluorescence. These 3 did, however, develop high antibody titers by all four criteria and they remained healthy throughout the examination period. These results clearly indicate that unprotected pros-weanling cats brought into a leukemia exposure household environment have a high risk of becoming infected with FeLV. Furthermore, a large proportion of the cats are at risk for development of persistent viremia and FeLV-related diseases.
Int J Cancer 1977 Jan
PMID:Horizontal transmission of feline leukemia virus under natural conditions in a feline leukemia cluster household. 18 73

[3H]Glucosamine labeling of untransformed cells, C-type virus-transformed cells, and virus-infected cells and subsequent analysis by polyacrylamide gel electrophoresis and fluorography permitted the detection of a Pronase-sensitive macromolecular labeling that appeared in about eight regions of radioactivity in every case. Reactions of cell extracts with antiserum to Tween-ether-disrupted purified murine leukemia virus revealed, in most transformed cells, two components with a mobility of about 100,000 daltons, whereas C-type virus-infected cells revealed their radioactivity mainly in a region nearer to that of the major viral glycoprotein at about 69,000 daltons. No comparable components were apparent from the reaction of transformed or infected extracts with preimmune serum or from the reaction of untransformed uninfected cells and immune serum.
Cancer Res 1977 Apr
PMID:Demonstration of different glycosylated antigens in C-type virus-transformed and infected rat cells by antiserum to murine leukemia virus. 19 Nov 79


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>