c-myc and c-fos Gene expression in Cultured Cutaneous Squamous Cell Carcinoma Cells Treated with Retinoic Acid

Abstract

Proto-oncogenes, and in particular the nuclear proto-oncogenes involved in transcriptional regulation, play a key role in the control of proliferation and differentiation of many cell types. Especially, the c-fos and c-myc oncogenes play a role on tumor growth and development. There is few reports of the effect of retinoic acid(RA) about the expression of these oncogenes in cultured cutaneous squamous cell carcinoma(SCC) cells. Our purpose is to elucidate the effect of RA on the expression of c-fos and c-myc oncogenes in cultured cutaneous SCC cells. The Northern blot hybridization using the 32P-labelled c-fos and c-myc cDNA treated with RA were performed in cultured cutaneous SCC cells. In cultured cutaneous SCC cells, the level of the c-fos and c-myc gene transcription was more decreased in the groups treated with retinoic acid(all-trans retinoic acid, 13-cis retinoic acid, retinol) than untreated. In cultured cutaneous SCC cells, the c-myc gene transcription was decreased extremely in the group treated with 13-cis retinoic acid among the groups treated with retinoic acids. In both cultured normal keratinocyte and cutaneous SCC cells, the c-fos gene expressions are more decreased than c-myc gene by retinoic acid. These results suggest that the RA-induced changes in cultured cutaneous SCC cells are primarily due to changes in c-fos and c-myc gene expression. Furthermore it may be a suppressive factor of the development of SCC.