IMBALANCE IN THE ANTIOXIDANT POOL IN MELANOMA-CELLS AND NORMAL MELANOCYTES FROM PATIENTS WITH MELANOMA

In order to evaluate the free radical defense systems of melanocytes a nd their possible correlation with melanoma, we have studied in cultur ed normal human melanocytes (20), normal melanocytes from melanoma pat ients (15), and melanoma cells (40) the fatty acid pattern of membrane phospholipids as a target of peroxidative damage and the superoxide d ismutase and catalase activities, vitamin E, and ubiquinone levels as intracellular antioxidants, Cells were cultured in the same medium and analyzed at III or IV passage. Compared to the values obtained in nor mal human melanocytes, melanoma cells showed on average: a) higher lev els of polyunsaturated fatty acids, b) increased superoxide dismutase and decreased catalase activities, higher vitamin E, and lower ubiquin one levels, Among the normal melanocytes from melanoma patients studie d, two groups were differentiated: a) cultures (7) with enzymatic and non-enzymatic antioxidants level similar to those of normal human mela nocytes; b) cultures (8) with antioxidant patterns similar to those ob served in melanoma cells, Polyunsaturated fatty acids were also increa sed in the latter group, The results indicate that in melanoma cells a nd in a percentage of normal melanocytes from melanoma patients, an im balance in the antioxidant system can be detected that can lead to end ogenous generation of reactive oxygen species and to cellular incapabi lity of coping with exogenous peroxidative attacks, These alterations could be correlated with the malignant transformation of cells and wit h the progression of the disease.