Treatment with Akt1/2 inhibitor Akti-1/2 is preferentially toxic for phospho-Akt–positive MM cells. (A) Western analysis of AMO-1, MM.1S, OPM-2, and U266 cells treated overnight with either 10 μM Akti-1/2 or a corresponding amount of solvent (DMSO). Whereas the levels of total Akt protein remained unaffected, phosphorylated forms of Akt and its substrate FoxO1/3a were strongly diminished in MM.1S and OPM-2 cells. (B) Viability of AMO-1, MM.1S, OPM-2, and U266 cells in coculture with BMSCs after 5 days of treatment with different concentrations of Akti-1/2. Survival was determined by annexin V–FITC/PI staining and expressed in relation to the viability of DMSO-treated control cells. The graph displays the results from 3 independent experiments; error bars mark standard deviations.