Effects of U0126, FPT-3, or FTI-277 treatment for 18 hours on the cell-cycle–dependent activation of MEK-1/2.

NB-4 cells were incubated in the absence or the presence of 50 μM FPT-3, 50 μM U0126, or 20 μM FTI-277. After 18 hours, double staining with propidium iodide and an antibody specific for activated PP-MEK-1/2 was performed as described in “Materials and methods.” Representative cell-cycle profiles (left) and FACS profiles of the double staining (right) are shown. (A) Untreated NB-4 cells; (B) solvent-treated (DMSO) NB-4 cells; (C) NB-4 cells treated with 50 μM FPT-3; (D) NB-4 cells treated with 20 μM FTI-277; (E) NB-4 cells treated with 50 μM U0126.