Effect of AZD6244 on cell-cycle profile and functional sequelae of ERK inhibition in MM cells. (A) INA-6 MM cells were treated with AZD6244 (2 μM) for the time intervals indicated. Cell-cycle profile was then evaluated by PI staining using flow cytometry. (B) INA-6 MM cells were treated with AZD6244 (0.1-10 μM) for 2 days, followed by PI/annexin V staining and flow-cytometric analysis. (C) CD138⁺ patient MM cells were incubated for 2 days with control media or AZD6244 (0.2 μM) and then subjected to PI/annexin V staining. (D) INA-6 MM cells in 10% FBS-containing medium were treated with AZD6244 for the intervals indicated and lysed, and whole-cell lysates were then subjected to immunoblotting using specific Abs.