The Ca2+ channel blocker verapamil enhances melanogenesis without altering metastatic potential in the B16 murine melanoma.

The relationship between the processes of melanogenesis and metastasis were investigated using metastatic variants of the B16 murine melanoma. alpha-Melanocyte stimulating hormone (MSH) enhanced lung colonization by the low metastasis variant F1 as well as inducing melanogenesis. The Ca2+ channel blocker verapamil had no effect on lung colonization by the F1 and ML8 variants but markedly enhanced melanogenesis in both these cell lines. We previously showed that the expression of the dominant metastasis associated gene mts1 was up-regulated by MSH but down-regulated by verapamil. These findings may demonstrate that the processes of melanogenesis and metastasis can be uncoupled at both genetic and phenotypic levels, and that the mechanisms involved in the regulation of metastatic behaviour and melanogenesis are different.