Establishment of a melanogenesis regulation assay system using a fluorescent protein reporter combined with the promoters for the melanogenesis-related genes in human melanoma cells.

There are two established depigmenting agent assays currently in use. However, these methods are unreliable and time-consuming. Therefore, it will be valuable to establish a better assay system for depigmenting agent analysis. In this study, we established a melanogenesis regulation assay system using a fluorescent protein reporter combined with the promoters for the microphthalmia-associated transcription factor (MITF), tyrosinase (Tyr) and dopachrome tautomerase (Dct) genes in MeWo human melanoma cells. We used several melanogenesis regulators, including theophylline, hesperetin, arbutin and rottlerin, to confirm the function of this assay system. The established MeWo/pMITF-EGFP, MeWo/pTyr-EGFP and MeWo/pDct-EGFP stable cells integrated the pMITF-EGFP, pTyr-EGFP and pDct-EGFP plasmids into their genomic DNA. These stably transfected cells were used to examine alterations in the expression of the MITF, Tyr and Dct genes. All of the tested compounds, including theophylline, hesperetin, arbutin and rottlerin, could be analyzed in the stable cells, producing reliable results. Therefore, we believe that this melanogenesis regulation assay system can be used as a rapid and reliable assay system to analyze the regulation of melanogenesis by many known or unknown compounds.