Docosahexaenoic acid inhibits melanin synthesis in murine melanoma cells in vitro through increasing tyrosinase degradation

Abstract

To investigate the effects of docosahexaenoic acid (DHA) on melanin synthesis and related regulatory mechanisms. B16F10 mouse melanoma cells were exposed to DHA for 3 d, and melanin content and tyrosinase activity were measured. Western blot analysis was used to analyze the protein levels in DHA-mediated signal transduction pathways. DHA (1-25 μmol/L) did not affect the viability of B16F10 cells, but decreased α-MSH-induced melanin synthesis in a concentration-dependent manner. DHA concentration-dependently reduced tyrosinase activity in the cells, but did not affect mushroom tyrosinase activity in a cell-free system. Furthermore, DHA treatment significantly reduced tyrosinase level without affecting microphthalmia-associated transcription factor (MITF) in the cells. DHA did not activate ERK and Akt in the cells. Pretreatment with the proteasome inhibitor MG132 (80 nmol/L) abolished DHA-induced tyrosinase reduction. DHA inhibits melanogenesis in B16F10 cells in vitro through increasing tyrosinase degradation. The results suggest that DHA may be a potential agent for treatment of hyperpigmentary disorders of skin.