Reduced viability and colony formation of AML cells after inhibition of BTK in combination with conventional chemotherapy. (A) AML blasts and CD34⁺ control cells were either untreated or treated with ibrutinib (1 µM) for 8 hours and then treated with either cytarabine (0.1 µM or 0.5 µM) or daunorubicin (0.05 µM or 0.1 µM) for 48 hours and then assessed by Cell TitreGlo. Values indicate mean ± SD of 3 experiments. (B) AML cells and control cells were either untreated or treated with ibrutinib (1 µM) for 8 hours and then treated with either cytarabine (0.1 µM) or daunorubicin (0.05 µM), and then colony-forming assays were performed to show the number of colonies. In all panels, the values indicate the mean ± SD from 3 independent experiments. *Statistical significance of P < .05 between the different treatment groups using Student t test.