Figure 7.

Melanin content does not alter sensitivity to 4-TBP. SK-MEL188 melanoma cells were cultured in growth medium with reduced tyrosine concentrations. When melanin content had been reduced approximately 10-fold, cells were passaged and treated with increasing concentrations of tyrosine to promote melanin synthesis. After 72 hours, the tyrosine-supplemented medium was replaced with media low in tyrosine and serum (4%), and cells were cultured for a further 72 hours to normalize gene expression. A melanin assay was then performed to verify differences in melanin content. Cells were dosed with increasing concentrations of 4-TBP, and a viability assay was performed at 72 hours. The error bars represent SD in four wells of one experiment. The experiment was done in triplicate, and a representative experiment is shown. No significant difference was found between melanoma cells with different melanin contents.