BMS-214662 treatment induces mitochondrial-mediated apoptosis in CD34⁺, CD34⁺38⁻, and CD34⁺38⁺ CML cells. (A) CD34⁺ CML cells were treated with 250nM BMS-214662 or BMS-225975 for up to 24 hours and observed under phase-contrast microscope. (B) Transmission electron microscopy of CD34⁺ CML cells treated with 250nM BMS-214662 for 12 hours. Arrows indicate mitochondria. (C) CD34⁺ normal and total CML CD34⁺, CD34⁺38⁻, and CD34⁺38⁺ cells were treated as indicated for 24 hours and conformational changes of Bax were measured (CD34⁺, n = 3; CD34⁺38⁻ and CD34⁺38⁺, n = 2). (D) MOMP was measured in CD34⁺ normal and total CML CD34⁺, CD34⁺38⁻, and CD34⁺38⁺ cells after 24 hours of treatment with 250nM BMS-214662 (n = 3). (E) Densitometry analysis showed release of cytochrome c in CML CD34⁺ cells to the cytoplasm after 24-hour treatment with 250nM BMS-214662 (n = 3). Error bars represent ± SD. *P = .026. (F) CD34⁺ CML cells were treated as indicated and levels of ROS were measured by FACS (n = 3).