Primary AML cells have increased sensitivity to complex III inhibition. (A-D) PBSCs (A,C) and AML patient samples (B,D) were treated with the indicated concentrations of rotenone or antimycin to block complex I and III, respectively. After 2 hours (rotenone) or 4 hours (antimycin) of treatment, cells were stained with 5 μM MitoSOX Red. After 30 minutes, the stain was replaced with Annexin V to detect apoptotic cells and cells were analyzed using a BD FACS Canto II flow cytometer with a High Throughput Sampler. Data represent the mean value of triplicates ± SD. Each curve represents a patient/normal sample. (E-F) For detection of the progenitor population, CD34-PE-Cy7 (Clone 8G12) and CD38-PE-Cy5 (Clone HIT2) antibodies were also added with mitosox. (G) Immunoblots of cell lysates from PBSCs and AML patients, probed with the indicated antibodies against SOD1 (Cu/ZnSOD), present in the intermembrane space as well as cytoplasm, and SOD2 (MnSOD), present in the matrix. Lower panel shows actin as a loading control. 30 μg of total protein loaded in each lane.