Cell cycle, melanin contents and apoptosis processes in B16 and Cloudman S91 mouse melanoma cells after exposure to cytostatic drugs

Free radicals are generated in cells during many metabolic processes and eliminated from an organism by complex enzymatic and nonenzymatic systems. Many chemical compounds--among others melanin, reveal antioxidative properties. In this work the influence of some cytostatic drugs (at EC50) on melanin content and on the apoptotic processes in mouse melanoma B16 and Cloudman S91 cells in vitro were investigated. The cells were incubated with adriblastin, actinomycin D, cytosine arabinoside, cisplatin, dacarbazine and vincristine. The number of viable mouse melanoma B16 and Cloudman S91 cells was estimated by flow cytometry analysis and melanin content in colorimetric assays. Apoptotic cells were detected using the annexin V-FITC test. The majority of tested cytostatic drugs caused an increase of melanin content in the cells of both melanoma lines, except cisplatin and dacarbazine in the case of B16 cells and dacarbazine in the case of Cloudman S91. Adriblastin, actinomycin D and vincristine evoked apoptosis in the both tested cell lines. Slight increase of melanin content in melanoma cells can be a cell answer to free radicals generation by some cytostatic drugs like adriblastin, actinomycin D and vincristine.