PAK1 inhibition induces apoptosis of AML cells. (A) MOLM-13, HL-60, THP-1, and KG1a cells were treated with increasing concentrations of IPA-3. Apoptosis was measured at 24 hours by flow cytometry using Annexin V and DAPI staining. Average of 2 independent experiments. (B) MOLM-13, HL-60, THP-1, and KG1a cells were treated with increasing concentrations of FRAX-597. Average of 2 independent experiments. (C) Human THP-1 AML cells were infected with lentiviruses targeting PAK1 for knockdown or a nontargeting control. Average of 2 independent experiments (***P < .001).