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At least 19 recordsLinked to original sources
PubMed1975

Transformation of human cells by SV40 virus.

Fibroblast cultures were prepared from skin biopsies from 29 patients and tested for their susceptibility to transformation by simian virus SV40. Cells with a normal chromosome complement showed a mean transformation frequency of 25/106 cells but for cells from a single patient with Fanconi's anaemia, the value was 152/106 cells. An increased susceptibility to transformation was observed for cells from 6 patients with Down's syndrome 3 patients with trisomy 18, a patient with trisomy 18 for 5% of cells and a patient with trisomy 13. No increased susceptibility to transformation was found for cells with a chromosome complement of XO, XXY, XX/XX + 8, XX + partial 15q or XX + 9p. The susceptiability to transformation was related to susceptibility to SV40 virus infection, as measured by the number of infected cells which contained SV40 virus induced T antigen. This latter test was technically easier to perform and could serve to detect persons of increased susceptiability to transformation, since this may indicate an increased risk of natural malignant disease.

Antigens, Neoplasm↗
PubMed1988

Immortalization and malignant transformation of hepatocytes by transforming genes of polyoma virus and of SV40 virus in vitro and in vivo.

Hepatocytes can be converted into permanently growing hepatocyte lines by the transforming genes of either polyoma virus or SV40 virus. In transgenic mice harboring SV40 virus sequences (strain 202) most of the hepatocytes in the liver during late fetal development display an immortalized phenotype in culture, which is apparent immediately after placing liver cells into primary cultures. We conclude that at the late fetal stage hepatocytes in the liver display similar properties which might be the "initiated" cell type discussed earlier, and while untransformed, is determined to become malignant at a later point in development. Immortalized hepatocyte lines derived from the transgenic animals display reduced growth factor requirements in culture, i.e., increased autonomy. With time in culture, cells become increasingly autonomous by further reduction of their growth requirements until the final autonomous state has been attained, i.e., growth in the absence of any growth factor or hormone. It remains to be seen whether the development towards HCC in the normal liver is accompanied by a similar increased autonomy of growth factors, as observed in cells in culture.

Animals↗
PubMed1966

Susceptibility of human diploid fibroblast strains to transformation by SV40 virus.

A quantitative system has been developed for the study of transformation of human diploid fibroblasts in culture by two oncogenic viruses, SV40 and the E46 strain of adeno 7-SV40 "hybrid" virus. Seven of the eleven cell strains derived from human skin biopsies when infected with SV40 (10(9) tissue culture infective doses per milliliter) gave rise to transformed colonies with approximately the same frequency (0.03 percent). Two strains derived from patients with Fanconi's anemia, an autosomal recessive disease associated with a high incidence of chromosome abnormalities and spontaneous neoplasms, gave values more than ten times higher. Two strains from persons heterozygous for this gene were also considerably more susceptible to viral transformation.

Anemia, Aplastic↗
PubMed1984

[Induction of the replicative synthesis of DNA by SV40 virus T antigen introduced into cells using liposomes].

The role of virus SV40 T-antigen in the induction of cell DNA synthesis during its incorporation into cell liposomes was studied, using monolamellar liposomes obtained by phase reversal with incorporated highly purified T-antigen. Immunofluorescence studies revealed that T-antigen effectively penetrates inside the cells and after 10 hours is accumulated in the nuclei, where its level remains unchanged for 24 hours. Injections of purified T-antigen into the renal cells of serum-starved CV1 monkeys resulted in an almost 10-fold increase in the number of DNA-synthesizing cells 18 hours after the exposure. The same effect was observed during stimulation of a 10% serum culture. Removal of T-antigen from the preparation by specific immunoadsorption eliminated this effect. Centrifugation of cells grown in the presence of bromodeoxyuridine in a CsCl gradient was used to demonstrate the replicative type of cell DNA synthesis during T-antigen induction.

Animals↗
PubMed1978

Inhibition of postreplication repair and the enhancement of induction of SV40 virus from transformed hamster kidney cells.

The induction by ultraviolet light of simian virus 40 (SV40) from two SV40--transformed hamster kidney cell lines is enhanced by caffeine. In order to investigate the mechanism responsible for this enhancement, the effect of caffeine on postreplication repair of DNA damaged by UV light was studied utilizing alkaline sucrose-gradient sedimentation. Caffeine at concentrations of 0.5, 1.0 or 2.0 mM inhibited the filling of gaps during postreplication repair. In addition, caffeine was found to potentiate cell killing by mitomycin C, an alkylating agent, and to enhance SV40 induction by mitomycin C. We postulate that the persistence of gaps in DNA, caused by the presence of caffeine, results in the enhancement of SV40 virus induction.

Caffeine↗
PubMed1975

Establishment of continuous multiple sclerosis brain cultures after transformation with PML-SV40 virus.

PML-SV40 virus was used to transform cells from explants and monolayer subcultures of human brain derived from biopsies or autopsies of MS cases, as well as from 1 case of Jakob-Creutzfeldt disease (JC), 1 case of amyotrophic lateral sclerosis (ALS) and several cases without CNS disease. The success of transformation depended on the growth condition of the culture at the time of infection but at present at least 14 cell lines, 10 derived from MS, 2 from JC, 1 from ALS and 1 from a normal non-CNS patient are maintained in continuous culture.

Amyotrophic Lateral Sclerosis↗
PubMed1988

Human bronchial epithelial cells with integrated SV40 virus T antigen genes retain the ability to undergo squamous differentiation.

Human bronchial epithelial cells transformed by either DNA virus infection (SV40 or Adenovirus 12-SV40 hybrid virus) or transfection with the SV40 large T antigen gene were studied for their ability to undergo squamous differentiation when exposed to 12-O-tetradecanoylphorbol-13 acetate (TPA), transforming growth factor-beta 1 (TGF-beta 1), or fetal bovine serum (FBS), agents that induce the squamous differentiation of normal human bronchial epithelial cells. Squamous differentiation occurred in all ten T-antigen-positive cell cultures when they were exposed to either FBS or TGF-beta 1, but none differentiated when exposed to TPA. From one cell line, designated BEAS-2B, two subclones were isolated, one of which was induced to undergo squamous differentiation by FBS, and a second that failed to undergo squamous differentiation and was mitogenically stimulated when exposed to serum. These phenotypically different subclones provide a new in vitro cellular system for delineating the mechanism(s) of human bronchial epithelial cell squamous differentiation in response to FBS or TGF-beta 1.

Antigens, Viral↗
PubMed1999

SV40 virus transformation down-regulates endothelin receptor.

Simian virus 40 (SV40) is an oncogenic DNA virus that induces malignant transformation. Endothelin (ET), a 21 amino acid peptide with mitogenic and anti-apoptotic effects, binds to G-protein coupled ETA and ETB receptors. This report examines the effect of SV40 transformation on the expression of ET receptors. Results from receptor binding and reverse transcription (RT)-polymerase chain reaction (PCR) studies show that human lung fibroblasts IMR90 and WI38 express both ETA and ETB receptors, and that the expression of both receptors is significantly down-regulated in IMR90-SV40 and WI38-SV40, cell lines derived from IMR90 and WI38 with SV40 virus transformation. Receptor binding and RT-PCR analysis of 3A(tPA-30-1), a cell line derived from human placenta that expresses a higher level of SV40 large T-antigen at the permissive temperature (33 degrees C) than at the restrictive temperature (40 degrees C), further demonstrates that there is an inverse correlation between the expression of SV40 T-antigen and the expression of ET receptor. ET-1 and fetal bovine serum stimulate DNA synthesis in non-transformed cells; however, proliferation of transformed cells is independent of either fetal bovine serum or ET-1. We conclude that SV40 transformation down-regulates the expression of ET receptors, and that expression of ET receptors is inversely correlated with expression of SV40 large T-antigen.

Antigens, Viral, Tumor↗
PubMed1978

[Quantitative analysis of the immunogenic activity of SV40 virus and the cells of tumors induced by this virus].

The study of specific antitumour immunity induced by onogenic SV40 virus and by cell of SV40 virus and by cells of SV40-induced tumour of Syrian hamster demonstrated direct correlation between the level of specific antitumour resistance and the immunizing virus and tumour cell doses. The minimal resistance-inducing dose of the wild type SV40 virus strain was 10 times higher than that of ts A-30 mutant of this virus. Minimal resistance-inducing dose of irradiated cells of the tumour was about 9 x 10(5) cells; a 10-fold increase of this dose significantly increased the specific antitumour immunity level.

Animals↗
PubMedDate not supplied

Comparison of spontaneous and ultraviolet-induced mutagenesis on naked SV40 DNA and SV40 virus.

Molecular aspects of mutagenesis in mammalian cells have been essentially analyzed using biological probes such as viruses and shuttle vectors. Although the main data concerning the specificity of carcinogen-induced mutations are similar, the observed spontaneous mutation frequencies are significantly different when using one or the other model. This frequency is considerably higher with shuttle vectors than with viruses. We have performed an analysis of mutagenesis in order to determine if the obligatory transfection step associated with shuttle vector technology was responsible for the high mutation frequency found with these molecules. For this purpose simian virus 40 (SV40) genome used as virus or as naked DNA was introduced into permissive cells by viral infection or DNA transfection respectively. Our results show that transfection alone does not induce a higher mutation frequency on SV40 DNA than virus infection. Moreover, we have shown that the ultraviolet-light induced mutation spectrum was similar on the SV40 VP1 gene after viral infection or DNA transfection.

Animals↗
PubMed1977

Detergent solubilization and partial purification of tumor specific surface and transplantation antigens from SV40-virus-transformed mouse cells.

A solubilization technique employing 0.5% Triton X-100 was developed to obtain both SV40 virus (SV40)-induced tumor-specific surface antigen(s) (TSSA) from SV40-transformed mouse cells, as determined by a serum-mediated microcytolytic assay, and tumor-specific transplantation antigen(s) (TSTA), as determined by in invivo experiments. High yields (approximately 50%) of TSSA were obtained in whole-cell extracts and also after ammonium sulfate fractionation. Additional fractionation of a 30-50% ammonium sulfate fraction by gel exclusion chromatography on Sephadex G-150 resulted in two pooled fractions which contained TSSA activity. The first eluted close to the void volume, and the second in the 45,000 molecular weight region. The various TSSA active fractions were also active in vivo TSTA tests. Detergent solubilization provides a suitable technique to recover the SV40-induced antigens in good yield, and apparently in intact form.

Antigens, Neoplasm↗