AX suppresses human LSCs and acts in a reasonable therapeutic window. (A) One BCR-ABL1+ CML patient sample and a relapse BCP-ALL patient sample, along with a healthy human-CB-derived CD34⁺CD38^+/− (sorted by MACS) sample, were treated with increasing concentrations of AX or controls (NB, AUY922, or IM). Later, the enzymatic activity of caspase-3/7 was examined using a caspase-3/7–dependent Glo assay after 5 days of treatment. (B) Primary patient samples along with healthy control cells (including primary B, T, and NK cells) were treated with the indicated concentration of AX or controls (NB, AUY922, or IM), and viable cells were counted after every 24-hour interval for 5 days. AX specifically targets leukemic samples (both the leukemic bulk and leukemic stem cell fractions) contrary to healthy control cells. (C) Supernatants were collected from primary T, NK, and B cells after 48-hour treatment with respective compound and then evaluated for the detection of 25 different human cytokines. Heat maps depict the fold difference relative to the control (DMSO) in picograms per milliliter. Some cytokines were omitted from the analysis because their concentration was below the detection limit. (D) CD34⁺CD38^+/− cells from 2 BCR-ABL1⁺ CML (CML-1 and CML-2) patient samples and 1 TKI-resistant BCR-ABL1⁺ BCR-ALL patient sample, along with healthy CB controls, were seeded in methylcellulose medium containing respective compounds at the indicated concentration after treatment in liquid medium for 24 hours. Colonies were counted after 14 days (n = 5). Significance analysis of normally distributed data with variance similar between groups used a paired, 2-tailed Student t test. *P < .05, **P < .005, ***P < .001. IFNa, interferon α; GM-CSF, granulocyte-macrophage colony-stimulating factor; TNFa, tumor necrosis factor α.