LB1597 Palmitoyl-KVK-L-ascorbic acid inhibits melanogenesis in B16F1 cells through the down-regulation of tyrosinase and MITF

Abstract

Palmitoyl-KVK-L-ascorbic acid (Duo-vitapep) is the whitening agent synthesized by conjugation of palmitoyl-KVK and ascorbic acid. In a previous study, we demonstrated the skin-whitening effect in clinical trial and the reduction of melanin contents in B16F1 cells. However, the underlying mechanism involved in melanogenesis has not elucidated yet. In this study, we investigated the expression of enzymes and their cellular signaling pathways involved in melanin synthesis. Treatment of B16F1 cells with Duo-vitapep reduced cellular tyrosinase activity but did not inhibit cell-free tyrosinase activity. In addition, the expression of tyrosinase decreased with dose dependent manner. However, Duo-vitapep did not regulate the gene expression of tyrosinase and level of AKT/p-AKT protein. These results suggest that Duo-vitapep inhibits melanogenesis by reducing the protein level of tyrosinase and might be involved in tyrosinase maturation or degradation pathway. Duo-vitapep also reduced the level of MITF protein, but did not change its mRNA expression and protein level of CREB/p-CREB. In contrast, phosphorylation of ERK1/2 protein significantly increased and PD98059 blocked the increased level of ERK1/2 phosphorylation by Duo-vitapep. These results suggest that Duo-vitapep decreased MITF protein level via phosphorylation of ERK1/2 and might relate with degradation pathway. In conclusion, Duo-vitapep inhibits the melanogenesis by down-regulation of tyrosinase and MITF.