title: Keratin modifications in epidermis, papillomas, and carcinomas during two-stage carcinogenesis in the SENCAR mouse.
abstract: To elucidate the role of keratin modification in tumor promotion, we investigated the keratin polypeptide patterns of mouse epidermis, papillomas, and carcinomas throughout an initiation-promotion experiment. The epidermal keratin modifications induced by repetitive 12-O-tetradecanoylphorbol-13-acetate treatments in both initiated and noninitiated mouse skin were essentially identical to those observed with a single 12-O-tetradecanoylphorbol-13-acetate application. These changes were even more pronounced in epidermal papillomas. In addition, the keratins of the papillomas displayed greater charge heterogeneity, particularly among the high-molecular-weight keratins (Mr 60,000 to 62,000). As the experiment progressed, there appeared to be a selective loss of one group of high-molecular-weight keratins (Mr 62,000) in some of the papillomas. Interestingly, the carcinomas that appeared at this time had significant reduction in both groups of high-molecular-weight keratins. In fact, the keratin profiles of carcinomas were very similar to the patterns observed in basal cells after a single 12-O-tetradecanoylphorbol-13-acetate treatment of adult epidermis. This may indicate that the program of keratin expression of a carcinoma becomes permanently fixed at a basal cell pattern. Changes in keratin patterns may serve as a biochemical marker of malignant progression in mouse epidermis.
mesh_terms: D000818:Animals; D002273:Carcinogens; D002277:Carcinoma / Q000139:chemically induced / Q000503:physiopathology*; D005260:Female; D007633:Keratins / Q000302:isolation & purification / Q000378:metabolism*; D051379:Mice; D008815:Mice, Inbred Strains; D008970:Molecular Weight; D009374:Neoplasms, Experimental / Q000503:physiopathology; D010212:Papilloma / Q000139:chemically induced / Q000503:physiopathology*; D012867:Skin / Q000378:metabolism*; D012878:Skin Neoplasms / Q000139:chemically induced / Q000503:physiopathology*; D013755:Tetradecanoylphorbol Acetate
chemical_list: D002273:Carcinogens; D007633:Keratins; D013755:Tetradecanoylphorbol Acetate