The involvement of p38 mitogen-activated protein kinase in the alpha-melanocyte stimulating hormone (alpha-MSH)-induced melanogenic and anti-proliferative effects in B16 murine melanoma cells.

Activation of p38 or p44/42 mitogen-activated protein (MAP) kinases has been shown to trigger differentiation in a number of cell types. The present study has investigated the roles of these kinases in the alpha-melanocyte stimulating hormone (alpha-MSH)-induced melanogenic and proliferative responses in B16 melanoma cells. Treatment of cells with alpha-MSH led to the time-dependent phosphorylation of both p38 and p44/42 MAP kinases. However, only inhibition of p38 MAP kinase activity with SB 203580 blocked both the alpha-MSH-induced melanogenic and anti-proliferative effects. It therefore appears that activation of the p38 pathway can promote melanogenesis and inhibit growth of B16 melanoma cells.