Figure 4.

The effect of secosteroids and cisplatin or dacarbazine on the distribution of human melanoma A375 cells through the cell cycle. Cells that were treated with 24 µM cisplatin for 48 h had been pre-treated with (A) 100 nM 1α,25(OH)₂D3, (B) 20(OH)D3, (C) 21(OH)pD or (D) calcipotriol for 24 h. Similarly, cells that were treated with 6 µM dacarbazine 48 h had been pre-treated with (E) 100 nM 1α,25(OH)₂D3, (F) 20(OH)D3, (G) 21(OH)pD or (H) calcipotriol for 24 h. The cells were harvested, stained with propidium iodide 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 versus untreated control or between the two groups indicated by the bracket. SubG1, apoptotic/necrotic cells; G1, growth; S, DNA synthesis; G2/M, preparation for mitosis/mitosis; 1α,25(OH)₂D3, 1α, 25-dihydroxyvitamin D3; 20(OH)D3, 20S-hydroxyvitamin D3; 21(OH)pD, 21-hydroxypregnacalciferol.