OSU03012 induces cytotoxicity toward CLL cells via apoptosis. (A) OSU03012 induces cytotoxicity toward CLL via apoptosis. After exposure to 10 μM OSU03012 for 24 hours, PBMCs from patients with CLLL were resuspended in binding buffer containing annexin V–FITC and propidium iodide and assessed by flow cytometry. Data are representative of 9 patients. (B) After treatment with 10 μM OSU03012 for 24 hours PBMCs from patients with CLL were washed once in RPMI 1640 media and then incubated in RPMI 1640 media containing 50 ng/mL rhodamine-123 for 30 minutes at 37°C. Stained cells were washed once in RPMI 1640 media, placed on ice, and analyzed by flow cytometry. Data are representative of 4 patients.