SP MF CD34⁺ cells responded to the treatment of AZD1480 in a dose-dependent fashion, whereas normal CB CD34⁺ cells were less responsive to the effects of AZD1480. (A-B) SP MF and CB CD34⁺ cells were cultured in the presence of AZD1480 at doses ranging from 50 nM to 500 nM for 3 days. After treatment, cells were analyzed by mAb staining and flow cytometry. The percentage of total cells (A) and CD34⁺ cells (B) generated in the cultures exposed to cytokines plus AZD1480 relative to those generated in the cultures exposed to cytokines alone is shown. *P < .05; **P < .01; ***P < .001 vs cytokines alone for SP MF or CB CD34⁺ cells, respectively (n = 4). (C-G) AZD1480 treatment did not affect normal CD34⁺ cells. The reduction in the absolute total number of CB cells (C), CD34⁺ cells (D), CD34⁺CD90⁺ cells (E), CD34⁺CXCR4⁺ cells (F), and assayable HPCs (G) in cultures exposed to cytokines plus AZD1480 compared with that detected in cultures exposed to cytokines alone was not statistically different. P all >.05 (n = 5).