Apoptosis of MC38/0 cells. Active caspase-3/7 (A) and subG1 stage (B) of MC38/0 murine colon cancer cells after 48 h incubation with vitamin D analogs and/or 5-FU. Vitamin analogs were used in concentrations of 100 nM. 5-FU was used at concentrations of 50 μg/ml and 200 μg/ml. Asterisks indicate statistically significant results as compared to the control Tukey HSD test for active caspase-3/7 and the Mann–Whitney U test for death cell (subG1) analysis.