Fig. 1

BM microenvironment protected CML CD34⁺ cells from IM-induced apoptosis. K562 CD34⁺ cells and primary CD34⁺ CML cells were cultured with or without hBMSCs for 12 h and then treated with various concentrations of IM (0, 0.125, 0.25, 0.5 μM) for 36 h, respectively. A, B Apoptosis was measured by Annexin V-PI double staining assay after treatment with IM in co-culture model or monolayer culture. C Apoptotic cells were observed by DAPI staining. Scale bar, 20 μm. D The growth inhibition effect of IM on CD34⁺ subpopulation in K562 cells or primary CML cells with or without the supernatant of hBMSCs was detected by MTT, and the inhibition rate (%) was evaluated. Data were expressed as means ± SD from three independent experiments. p* < 0.05, p** < 0.01, p*** < 0.001 versus the group treated with IM in monolayer culture