Figure 4.

Effect of PKC and ERK inhibitors on HL-60 cell differentiation induced with PT alone or in combination with 1,25-(OH)₂D₃. HL-60 cells were treated for 40 min with varying concentrations of PKC inhibitors (chelerythrine, H-7) or an ERK inhibitor (PD-098059), followed by incubation with 10 μM, 5 nM 1,25-(OH)₂D₃, or 10 μM PT in combination with 5 nM PT 1,25-(OH)₂D₃ for 72 h. The cellular differentiation was assessed by the NBT reduction assay. The results are presented as percentages of the differentiated cells with the mean±s.e.mean (n=3).