WNT974 in combination with nilotinib significantly reduces leukemic stem and progenitor cells in the BM and spleen of transgenic BCR-ABL mice. (A) BCR-ABL expression was induced in SCL-tTA-BCR-ABL mice by tetracycline withdrawal. BM cells were obtained 3 weeks after induction and transplanted into wild-type FVB/N recipient mice irradiated at 750 cGy (10⁶ cells/mouse; 6-8 mice/group). Three weeks posttransplantation, treatment with vehicle, NIL (50 mg/kg), WNT974 (5 mg/kg), or a combination was initiated. PB WBC counts (B), PB neutrophil counts (C), BM cellularity (D), spleen size (E), absolute number of LTHSC (F), STHSC (G), MPP1 (H), MPP2 (I), CMP (J), GMP (K), and MEP (L) in the BM were evaluated after 2.5 weeks after drug treatment. Error bars represent mean ± SEM. *P < .05.