A. HEL92.1.7 and HEL cells made persistent to ruxolitinib (HEL/Persisters) were treated with the indicated concentrations of ruxolitinib for 48 hours. Then, the % of annexin V- and TO-PRO-3-positive, apoptotic cells was determined by flow cytometry. Columns represent the mean of three experiments; Bars represent the standard error of the mean. * indicates apoptosis values significantly less in HEL/Persister cells than in parental cells (p<0.05). B. HEL92.1.7 and HEL/Persisters were treated with the indicated concentrations of JQ1 for 48 hours. Following this, the % of annexin V-positive, apoptotic cells was determined by flow cytometry. Columns represent the mean of three experiments; Bars represent the standard error of the mean. C. HEL/Persister cells were treated with JQ1 and AUY922 at a constant ratio for 24 hours. Then, the % of annexin V-positive apoptotic cells was determined by flow cytometry. The median dose effect and combination indices (isobologram) were determined utilizing Compusyn software assuming mutual exclusivity. Combination index (CI) values less than 1.0 indicate a synergistic interaction of the two agents in the combination.