Stimulation of melanin synthesis in melanoma cells by cold plasma.

Skin color is derived from epidermal melanocytes that contain specialized organelles in which melanin is formed. The formation of melanin is a well-orchestrated process, and reactive oxygen species (ROS) play a role in numerous enzymatic conversions, such as the reactions catalyzed by tyrosinase and tyrosine hydroxylase. Currently, there is ample evidence that cold plasma exerts biological effects on cells through the impact of ROS and reactive nitrogen species (RNS). Modulation of melanin biosynthesis by cold plasma has not yet been investigated. This study investigated melanin biosynthesis of human melanoma cell lines with different endogenous melanin contents (SK-Mel 28, G-361, FM-55-P and MNT-1) in response to cold plasma-derived reactive species. Initially, the distribution of melanosomes, via immunofluorescence, and the influence of microphthalmia-associated transcription factor (MiTF), as a key transcription factor, was investigated. In our experimental setup, all of the tested cell lines had an elevated melanin content after exposure to cold plasma. These promising results suggest a novel potential application of cold plasma for the regulation of melanogenesis and may be a useful tool for influencing skin color in the future.