Fig. 2

Arsenic trioxide (ATO) cooperates with homoharringtonine (HHT) to induce apoptosis in leukemia stem-like cell lines. Cells were treated with HHT, ATO, or HHT + ATO for 2 days, and apoptosis of Kasumi-1 (a) and KG-1 (b) cells was detected with PI/Annexin V and FACS. Error bars represent three independent experiments. P < 0.05*, P < 0.01**, P < 0.001***. Hochest dye was used to evaluate the shape of the nuclei of Kasumi-1 (c) and KG-1 (d) cells under fluorescence microscopy