KERATIN MODIFICATIONS IN EPIDERMIS, PAPILLOMAS, AND CARCINOMAS DURING 2-STAGE CARCINOGENESIS IN THE SENCAR MOUSE

  • 1 January 1982
    • journal article
    • research article
    • Vol. 42  (10) , 4176-4181
Abstract
To elucidate the role of keratin modification in tumor promotion, the keratin polypeptide patterns of mouse epidermis, papillomas and carcinomas were investigated in an initiation-promotion experiment. Epidermal keratin modifications induced by repetitive 12-O-tetradecanoylphorbol-13-acetate treatments in 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. The keratins of the papillomas displayed greater charge heterogeneity, particularly among the high-MW keratins (MW 60,000-62,000). As the experiment progressed there appeared to be a selective loss of 1 group of high-MW keratins (MW 62,000) in some of the papillomas. The carcinomas that appeared at this time had significant reduction in both groups of high-MW keratins. 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.