12-O-Tetradecanoylphorbol-13-acetate promotion of carcinogen-treated rat liver endothelial cells.

Established RLC-1 adult rat liver endothelial cells were utilized to assess promotional requirements of hepatic endothelial elements to malignant transformation following in vitro exposure to carcinogens requiring metabolic activation. Diethylnitrosamine failed to transform RLC-1 cells with or without tetradecanoylphorbol acetate (TPA) promotion. Benzo (a) pyrene was previously shown to initiate certain growth changes in the RLC-1 line; these cells, however, required TPA promotion prior to expression of the fully transformed phenotype.