Inhibition of ERK enhances VS-5584-induced cell death in AML cell lines. (A, B) MOLM-13, U937, and THP-1 cells were treated with VS-5584 (VS), SCH772984 (SCH), or VS + SCH for 48 h. Whole cell lysates were subjected to Western blots which were probed with the indicated antibodies. Representative blots are shown; normalized densitometry measurements are indicated below the corresponding blot. For panel A, * indicates p < .05 compared to the control (n = 3). For panel B, #indicates p < .05 compared to individual drug treatment and * indicates p < .05 compared to VS treatment (n = 3, data not shown). (C) AML cell lines were treated with VS, SCH, or in combination for 48 h Annexin V-FITC/PI staining and flow cytometry analysis was performed. Mean percent Annexin V+ cells ± SEM are shown. CI values were calculated using CompuSyn software. *** indicates p < .001.