Melanization of Bomirski hamster amelanotic melanoma cells (Ab line) depends on the type of culture medium.

INTRODUCTION: The effect of melanogenesis intensity on melanoma biology remains an open question, and the biological differences between melanotic and amelanotic melanoma cells have not yet been satisfactorily documented. As a result, the melanization of melanoma cells in in vitro cultures is not considered among experimental procedures. The aim of this study was to investigate the effect of the medium used to culture Bomirski amelanotic Ab melanoma cells on the melanogenesis process.

MATERIAL AND METHODS: Amelanotic melanoma cells (Ab) were cultured in two media recommended for in vitro melanoma cell cultures, RPMI and DMEM. The melanization was evaluated by determining the melanin and tyrosinase presence in the cells using spectrophotometrical and western blot methods, respectively. Changes in Ab melanoma cells' ultrastructure were determined using electron microscopy (EM).

RESULTS: The medium with higher level of tyrosine (DMEM) induced significant melanization of amelanotic melanoma cells (Ab) after only 24 h, while the RPMI medium, with a lower level of tyrosine, weakly affected melanin production. Melanization of Ab cells was paralleled by an increase in the amount of tyrosinase protein. Induced melanization was easily observed on EM-micrographs in the form of newly formed melanosomes containing melanin pigment. Melanosomes at stages from one (I) to four (IV) were observed.

CONCLUSIONS: Culture medium has an important effect on the in vitro biology of amelanotic melanoma cells, since it can affect the rate of cellular melanization. The appropriate medium should be carefully selected, taking into account the known biology of the melanoma cells being used.