AKT signaling is required for the survival of MM cells. (A) Percentage of specific cell death of HMCLs (n = 9) treated with increasing concentrations of the adenosine triphosphate–competitive AKT inhibitor GSK2110183 (afuresertib) (left panel) and the allosteric AKT inhibitor MK2206 (right panel) for 3 days. Specific cell death was calculated based on 7-AAD viability dye staining and flow cytometry. Mean values of 3 independent experiments are shown. (B) Percentage of cell death of primary MM plasma cells from patients (n = 6) treated with 2.5 μM MK2206 AKT inhibitor for 3 days. Specific cell death was calculated based on 7-AAD viability dye staining and flow cytometry. Means of 3 technical replicates are displayed (Wilcoxon signed-rank test, *P < .05). (C) Immunoblot analysis of protein expression in AKT-inhibitor treated HMCLs LME-1, MM1.S, XG-1, XG-3, ANBL-6, LP-1, OPM-2, UM-3, and RPMI-8226. Cells were serum starved for 1 hour, after which they were incubated in medium containing 10% FCS with or without 2.5 μM MK2206 for 2 hours. Shown are the indicated proteins; β-actin was used as a loading control. Representative immunoblot of at least 2 independent experiments is shown. (D) Immunoblot analysis of protein expression in primary MM patient plasma cells (n = 4) serum starved for 1 hour, after which they were incubated in medium containing 10% FCS with or without 2.5 μM MK2206 for 2 hours. Shown are the indicated proteins; β-actin was used as a loading control.