title: Enhancement of simian virus 40-induced transformation of nude mouse skin fibroblasts by 3-methylcholanthrene.
abstract: Secondary cultures of newborn NMRI nu/nu (nude) mouse skin fibroblasts were used as targets for transformation by the combined administration of SV40 and 3-methylcholanthrene (MC). The SV40-induced transformation was enhanced both by pre- and post-treatment with MC at concentrations which themselves were nontransforming. The short pretreatment caused a 2-fold enhancement in the transformation frequency at a low concentration of MC that allowed greater than 50% of the cells to survive. A short post-treatment also caused a concentration dependent enhancement in SV40 transformation of the same magnitude. The long (72 h) post-treatment with MC increased virus transformation as much as 4.3-fold. In contrast, anthracene, a non-carcinogenic compound, had no effect on the viral transformation frequency. An analysis of the morphology of the foci revealed that long post-treatment with MC induced a high number of type I foci. Combination dishes lacked these foci almost completely, and the enhancement was due to the increased number of type II and type III foci.
mesh_terms: D000818:Animals; D002471:Cell Transformation, Neoplastic / Q000187:drug effects*; D002478:Cells, Cultured; D005347:Fibroblasts / Q000187:drug effects; D007700:Kinetics; D008748:Methylcholanthrene / Q000633:toxicity*; D051379:Mice; D008819:Mice, Nude; D013539:Simian virus 40 / Q000235:genetics*; D012867:Skin / Q000187:drug effects*
chemical_list: D008748:Methylcholanthrene