Loss of Cdc42 leads to MA9 cell differentiation. (A) Cdc42KO-MA9 leukemia cells had a differentiated immunophenotype and (B) a delayed increase in apoptosis. (C) Overexpression of the prosurvival protein Bcl-xL was not sufficient to rescue the loss of CFU on deletion of Cdc42. (D) Cdc42KO-MA9 cells showed a differentiated cellular morphology on Wright-Giemsa stain compared with Cdc42FL controls. (E) Cdc42KO-MA9 leukemia cells had no significant difference in cell cycle analysis. (F) Relative expression of the myeloid differentiation gene Egr1 was increased in Cdc42KO-MA9 cells normalized to Gapdh. Data are representative of 3 to 5 independent experiments. SSC, side scatter.