Stimulation of melanogenesis in murine melanoma cells by 2-mercapto-1-(beta-4-pyridethyl) benzimidazole (MPB)

The effects of 2-mercapto-1-(beta -4-pyridethyl) benzimidazole (MPB), one o f the benzimidazole derivatives designed for a nucleic acid analogue, on me lanogenesis of murine B16-F10 melanoma cell lines were investigated. MPB (4 0 muM) induced a striking dendricity in B16 melanoma cells within 12 h and maximal dendricity between 48 and 72 h. The stimulation of melanin synthesi s was observed after only 2 days of treatment together with a dose-dependen t growth inhibition. Moreover, MPB increased the activity of tyrosinase thr ough the expression of tyrosinase mRNA without increasing the intracellular cyclic AMP content. MPB-induced melanogenesis was inhibited by novel prote in kinase A inhibitors, KT-5720 and H-85. These findings indicate that MPB stimulated B16 cells to terminally differentiate and may be a useful drug i n studying the regulation of melanogenesis. (C) 2000 Elsevier Science B.V. All rights reserved.