The biology of three
amelanotic melanoma cell lines (Ab, B16F10, and A375) of different species origin was analyzed during in vitro induced melanization in these cells.
Melanin production was induced by DMEM medium characterized by a high level of
L-tyrosine (a
basic amino acid for melanogenesis). The biodiversity of
amelanotic melanoma cells was confirmed by their different responses to melanogenesis induction; Ab hamster
melanomas underwent intensive melanization, mouse B16F10 darkened slightly, while human A375 cells did not show any change in
melanin content. Highly melanized Ab cells entered a cell death pathway, while slight melanization did not influence cell biology in a significant way. The rapid and high melanization of Ab cells induced apoptosis documented by
phosphatidylserine externalization,
caspase activation, and mitochondrial energetic state decrease.
Melanoma cell type, culture medium, and time of incubation should be taken into consideration during
amelanotic melanoma cell culture in vitro.
L-tyrosine, as a concentration-dependent factor presented in the
culture media, could stimulate some
amelanotic melanoma cell lines (Ab, B16F10) to
melanin production. The presence of
melanin should be considered in the examination of antimelanoma compounds in vitro, because induction of
melanin may interfere or be helpful in the treatment of
amelanotic melanoma.