KPT-9274 significantly inhibits proliferation and induces apoptosis of AML cell lines. (A) Apoptosis as measured by using annexin V/propidium iodide (PI) flow cytometric analysis at 24, 48, and 72 hours in 5 AML cell lines treated with KPT-9274. (B) Caspase-9, caspase-3, and poly (ADP-ribose) polymerase (PARP) cleavage after treatment of KPT-9274 at 24, 48, and 72 hours in MV4-11 and THP-1 cell lines. (C) Colony assays using patient primary cells (n = 11) after KPT-9274 treatment and 14 days of plating. (D) Replating of patient primary samples (n = 6) after treatment and 14 days of plating in MethoCult medium.