Experimental Study on Differentiation of Human Melanoma Cell Line Induced by Retinoic Acid

The human melaonma cell line was used as study for experimental differentiation by retinoic acid （RA）. The results showed: RA had a certain effect of growth inhibition for melanoma; doubling times of the cells was delayed; melanoma cells treated by RA were transplanted into nude mouse subdermatos and the growth of the tumors became slow; the melanoma cells may transform from epithelioid cells into fibroblast-like or dentritic cells. Elcctronmicroscopically, the cells with RA treatment had more organella. Melanosomes could be found in some cells. Immunohistochemically, HLA-DR was positive in control group and negative in RA treatment group. The tyrosinase activity appeared potentially increasing. Oncogene v-src expression decreased. These results suggested that the effects of RA were various ways, including cell surface antigen, oncogene and enzyme activity etc.