Assessment of apoptosis by Yo-pro-1 and propidium iodide (PI) in HBL-2 and Granta cell lines. (A,B) Treatment with AT-101 (1 μM or 2 μM) and carfilzomib (C, 6 nM or10 nM) induces apoptosis in at least 50% of cells (P ≤ .046 for Granta and P ≤ .016 for HBL-2). (C,D) The combination of AT-101 (1 μM or 2 μM) and bortezomib (1 nM, 3 nM, or 6 nM) may be antagonistic. Error bars represent SD.