Sk mel 2 cells

SK-Mel-2 cells were purchased from the Korean Cell Line Bank (KCLB, Seoul, Korea) and cultured in Dulbecco’s modified Eagle’s medium (DMEM) supplemented with 10% fetal bovine serum (FBS) and 1% penicillin/streptomycin at 37 °C in a humidified atmosphere with 5% CO₂. Cells suspended in culture medium containing 10% FBS were transferred into a flat-bottom 96-well plate. The number of cells/well was calculated to reach the same confluence for all cell culture dishes: 9 × 103 cells/well for 96-well plates, 2.5 × 105 cells/well for 6-well plates, 7.5 × 105 cells/well for 60 mm dishes, and 2 × 106 for 100 mm dishes. Cells passaged fewer than 10 times were used at about 70–80% confluence. Cells were treated with H₂O₂ for 1 h to induce melanogenesis. Cell viability was determined with an established colorimetric method using 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide inner salt (XTT) obtained from WelGene (Seoul, Korea).