OxPhos inhibition increases the number of functional mitochondria in OCI-AML3 cells cocultured with MSCs. (A) OCI-AML3 cells were treated with the OxPhosi IACS-010759 (30 nM) for 72 hours with or without cocultured MSCs. Representative electron microscopy images showing the increased numbers of small mitochondria in IACS-010759–treated OCI-AML3 cells cocultured with MSCs (left panel). The number of mitochondria inside OCI-AML3 cells was counted in more than 10 image fields at ×40 magnification by live-cell imaging with confocal microscopy. (B) Mitochondrial DNA copy number was assessed by quantitative polymerase chain reaction. Mitochondrial DNA content was normalized to nuclear DNA content. Data are presented as the mean of 3 independent experiments. (C) OCI-AML3 cells were treated with IACS-010759 (30 nM) for 4 hours with or without cocultured MSCs. The JC-1 monomer with green fluorescence reflects mitochondria with collapsed membrane potentials, and aggregated JC-1 with red fluorescence reflects mitochondria with intact membrane potentials. The ratio of the red and green optical density is shown. Data are presented as the means of 3 independent experiments. Error bars in the graphs show the means ± SDs of the results from 3 independent experiments. *P < .05; **P < .01.