Transcriptional induction of urokinase in cultured human kidney carcinoma cells by tetradecanoyl‐phorbol‐acetate

A cell line derived from a human kidney carcinoma produces in vitro the urinary type of plasminogen activator (urokinase). The synthesis of plasminogen activator is enhanced by 12-O-tetradecanoyl-phorbol-13-acetate(TPA); the increase can be followed both in the cell lysate and in the culture medium. The effect requires RNA and protein synthesis as well as the continuous presence of the inducer. Immunofluorescence and immunoprecipitation experiments with monospecific antiurokinase IgG show that kidney carcinoma cells synthesize a 50,000-dalton urokinase and TPA enhances the synthesis of the same molecular species. Hybridization of the total cellular RNA to a human urokinase cDNA probe shows that TPA increases the urokinase mRNA level.