Effects of inhibitors of tumor promotion on 12-O-tetradecanoylphor-bol-13-acetate-induced keratin modification in mouse epidermis

Abstract
In order to investigate the role that hyperplasia plays in the induction of the keratin modifications by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA), the effects of several inhibitors of tumor promotion and cycloheximide on the TPA-induced protein changes were studied. The anti-inflammatory steroid fluocinolone acetonide and cyclohex-imide, which prevent the induction of hyperplasia, were found to prevent the appearance of the TPA-induced keratin modifications. Retinoic add and tosylphenylalanylchloro-methyl ketone, which have minor influence on hyperplasia, were found to have essentially no effect on these protein changes. These results provided further evidence that the TPA-induced epidermal keratin changes were associated with the induction of hyperplasia by TPA and not necessarily related to promoting ability.