Sensitivity and resistance of human melanoma cells to ultraviolet radiation

A human melanoma cell line (MM253) was found to be sensitive to ultraviolet (UV) radiation, having a Do of 1.0 J/M2 when cloned on plastic culture dishes and a Do of 2.3 J/m2 when cloned in agar. These figures are much lower than those obtained for all other human melanoma cell lines studied in this laboratory (Do of 32-40 J/m2) and demonstrate that MM253 is unusually UV sensitive. The increased level of UV sensitivity in MM253 is not due to a reduced capacity for excision of pyrimidine dimers, repair of DNA single-strand breaks or elongation of newly-synthesized DNA strands when comparison is made with a UV-resistant melanoma cell line.