Saikosaponin b₂ Induces Differentiation without Growth Inhibition in Cultured B16 Melanoma Cells

抄録

Treatment with 5 μM of saikosaponin (SS) b₂ for 30 days was found to induce differentiation of B16 melanoma cells, with potentiation of expressions of melanogenesis and tyrosinase. To explore the mechanism of this effect, we observed the cell growth, cell cycle and morphology, and found that SSb₂ did not affect any of these parameters. That is, SSb₂ induced the differentiation of B16 melanoma cells without growth inhibition or cytotoxicity under conditions of low dose and long-term treatment. Phorbol ester, a protein kinase C (PKC) activator, markedly inhibited the expressions of melanogenesis and tyrosinase in both the control B16 melanoma cells and the long-term treated B16 melanoma cells. Down-regulation of the PKC activity may be involved in the effects of SSb₂.