Expression of intermediate filament proteins by normal and transformed mouse epidermal keratinocytes in culture

The aberrant expression of embryonic simple epithelial keratins K8 and K18 has been previously detected in chemically-induced mouse skin carcinomas and in cultured epidermal keratinocytes containing H-ras oncogenes. In this study, we report that cell lines derived from benign papillomas do not generally synthesize simple epithelial keratins, regardless of the presence of H-ras gene alterations. These results reinforce our previous suggestion that the expression of these keratins during mouse epidermal carcinogenesis is a marker of malignant transformation. The comparison of the two-dimensional electrophoresis intermediate filament protein profiles of transformed keratinocytes in culture, reveal that during in vitro progression to the malignant phenotype increased synthesis of simple epithelial keratins is associated to a general disturbance on the expression of cytoskeletal proteins.