Figure 6.

The effect of pre-treatment of human melanoma A375 cells with vitamin D derivatives on the dacarbazine-induced changes in the mitochondrial membrane potential and ROS levels. A375 cells were treated with (A) 100 nM 1α,25(OH)₂D3, (B) 20(OH)D3, (C) 21(OH)pD or (D) calcipotriol for 24 h, and subsequently exposed to 2.0 or 10 µM dacarbazine for 3 h The cells were stained with JC-1 and analyzed by flow cytometry. The positive control was exposed to CCCP for 5 min prior to staining with JC-1. (E) The effect of 1α,25(OH)₂D3 on ROS levels. The cells were treated with 100 nM 1,25(OH)₂D3 for 24 h and subsequently exposed to 6 µM dacarbazine for 1 or 24 h. The cells were stained with H₂DCFDA and analyzed by flow cytometry. The data are presented as the mean ± standard deviation (n=3). ^*P<0.05, ^**P<0.01 and ^***P<0.001, calculated using one way analysis of variance followed by Tukey’s multiple comparison test between the two groups indicated by the bracket or compared with the untreated control. 1α,25(OH)₂D3, 1α,25-dihydroxyvitamin D3; 20(OH)D3, 20S-hydroxyvitamin D3; 21(OH)pD, 21-hydroxypregnacalciferol; CCCP, carbonyl cyanide 3-chlorophenylhydrazone; ROS, reactive oxygen species.