A novel protein (p10) induced by 12-O-tetradecanoyl-phorbol-13-acetate (TPA) and other hyperplasiogenic tumor-promoting and non-promoting agents in murine epidermis

Treatment of murine epidermis with the tumor promotor 12-O-tetradecanoylpho rbol-13-acetate (TPA) shows characteristic and significant changes in prote in expression analyzed by 2D PAGE, compared to that of acetone-treated mous e epidermis. Of the seven de novo expressed proteins in TPA treated murine epidermis, one is a 44 kDa protein (p44) located nearby actin, and six prot eins are in the low-molecular range between 10-20 kDa (p10, pY, pCa, p1, p2 and p3). Interestingly, the incomplete promoting and inflammative hyperpla siogen 12-O-retinoylphorbol-13-acetate (RPA) and the non-promoting but infl ammative and hyperplasiogenic calcium-ionophore A23187 induced the same pat tern of proteins observed in the pidermis of mice treated with TPA, with mi nor quantitative differences. In all cases, p10 expression was quantitative the most abundant. Partial sequencing of this protein has led to the concl usion that it is a novel protein with no such sequences in the database com parisons using FASTA and TFASTA computer programs of Genetics Computer Grou p. The data presented here do not strictly support the functional role of d e novo induced proteins to tumor promotion, but show a causal relationship to hyperplasiogenic potency of TPA, RPA and A23187.