Effects of CBFA2T3 knockdown on p21 gene expression and the biological activities of non-t(8;21) AML cells. (A) CBFA2T3 RT-qPCR analyses showing effects of CBFA2T3 knockdown on p21 messenger RNA (mRNA) levels in the indicated AML cells. (B) Effects of CBFA2T3 knockdown on cell growth of the indicated AML cells. Cells were counted daily starting at 4 days after lentiviral transduction. (C) Flow cytometric, cell cycle quantification of control, and CBFA2T3-knockdown AML cells stained with propidium iodide. Error bars represent the standard error of 3 independent biological replicates. (D) BrdU incorporation and flow cytometry was used to independently confirm the G1/S block observed with propidium iodide staining. (E) Representative bioluminescence images (left, images are of the highest-signal mouse from each group) and average luminescence intensity (right) of control and CBFA2T3-depleted U937 cell-engrafted NSG mice over a period of 16 days. 1 × 106 cells were transplanted into NSG mice 5 hours after radiograph radiation (2.25 Gy). (F) Survival of the control and CBFA2T3-depleted U937 cell-engrafted NSG mice described in panel E. *P < .05; **P < .01; ***P < .001. GAPDH, glyceraldehyde-3-phosphate dehydrogenase.