Showing papers by "Torrey Pines Institute for Molecular Studies published in 1976"

Chemical-viral co-carcinogenesis: requirement for leukemia virus expression in accelerated transformation.

Abstract: The essential role of Rauscher leukemia virus (RLV) multiplication in viral—chemical co-carcinogenesis was investigated by the use of ethidium bromide (EtBr) as an inhibitor of viral complementary DNA (cDNA) integration in the host genome. EtBr inhibited co-carcinogenic transformation when present at the time of RLV inoculation but was ineffective when added to preinfected cells. Inhibitors of protein synthesis, puromycin and cyclohexamide also inhibited co-carcinogenic transformation of chronically infected cells. Purified rat interferon used at a concentration which inhibited 85% of RLV production did not modify the course of co-carcinogenic transformation. The implications of these observations in terms of the possible role of the virus-specific protein(s) in the co-carcinogenic process are discussed. Co-carcinogeneise chimio-virale: necessite de l'expression du virus de la leucemie pour accelerer la transformation Le role essentiel de la multiplication du virus de la leucemie de Rauscher (R L V ) dans la co-carcinogenesechimio-virale a ete etudite; on a utilise le bromure defhidium (EtBr) comme inhibiteur de l'integration de I'ADN complementaire (ADNc) du virus dans le genome de Iete. Si le milieu de culture contenait de I'EtBr au moment de l'inoculation de RL V, la transformation co-carcinogene Ptait inhibee, mais 1'EtBr n'a eu aucunefet lorsqu'il a ete ajoue aux cellules prinfecttes. La puromycine et la cyclohexamide, qui inhibent la syn-these des proteines, ont aussi inhibe la transformation co-carcinogtne des cellules chroniquement infectees. L'interferon purife de rat, utilise ri une concentration qui inhibait 85 % de la production de RL V, n'a pas modifie le processus de transformation co-carcinogtne. Les auteurs analysent les implications de ces observations du point de vue du rǒ1e possible de la (des) proteine (s) sptcque (s) du virus dans le processus co-carcinogene.

The co-carcinogenic activity of 4-nitropyridine-1-oxide (4-NPO) and prevention of transformation by type-specific anti-viral antibodies.

Abstract: Fischer rat embryo cells chronically infected with Rauscher murine leukemia virus, and known to be sensitive to transformation by potent chemical carcinogens, were transformed by the weak carcinogen 4-nitropyridine-1-oxide. Transformed cells grew in semi-solid agar and produced tumors in newborn Fischer rats. Transformation was inhibited by antisera specific for the ecotropic Rauscher murine leukemia virus, but not by antisera of equal toxicity specific for xenotropic Swiss mouse AT-124 virus.