2-Ethoxybenzamide stimulates melanin synthesis in B16F1 melanoma cells via the CREB signaling pathway

Non-steroidal anti-inflammatory drugs are frequently used for the treatment of inflammation, pain, and fever. In this study, we found that 2-ethoxybenzamide (ETZ) significantly enhanced melanin synthesis in B16F1 melanoma cells, and also induced melanosome formation. Therefore, we investigated the mechanism by which ETZ up-regulated melanin synthesis. Western blot analysis demonstrated that ETZ increased melanogenic protein levels, except that for TRP-2. Moreover, semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and real-time RT-PCR analyses showed that ETZ enhanced the mRNA levels of melanogenic genes, including microphthalmia-associated transcription factor and melanocortin 1 receptor. We also observed phosphorylation of cAMP response element-binding protein (CREB) following ETZ treatment. However, ETZ did not affect intracellular cAMP levels. ERK was also activated by ETZ treatment, and melanin content was enhanced upon treatment with the specific ERK inhibitor PD98059. Together, our results indicate that ETZ induces melanin synthesis via CREB phosphorylation.