Effect of bortezomib on CD34⁺38⁻ and undivided CML cells. (A) CD34⁺38⁻ (n = 3) cells were cultured in SFM+5GF and analyzed at 24 hours. The viable cell count (□) is expressed as a percentage of untreated cells (cell count %). The percentage of cells staining positive for 7-AAD (▴) is expressed on the y-axis (% cells apoptotic). (B) The effect of bortezomib on CD34⁺38⁻ (■) and CD34⁺38⁺ (□) cells (n = 3) was compared. The viable cell count is expressed as in panel A. (C) CD34⁺38⁻ (n = 2) cells from non-CML samples were cultured in SFM+5GF and analyzed at 24 hours. The viable cell count (□) and percentage of apoptotic cells (▴) are derived as in panel A. (D) CD34⁺ CFSE-stained CML cells were cultured in SFM+5GF and analyzed by flow cytometry at 72 hours. Cell division peaks were calculated relative to demecolcine control. The percentage of residual viable cells in each division peak is shown for untreated (■), or treated with 150nM dasatinib (), 10nM bortezomib (▩), and 20nM bortezomib (□). Cell recovery calculations for cells from all division peaks (E) and for undivided cells (F) in untreated and treated cells (bortezomib [bor] and dasatinib [das]). All results represent mean ± SEM with predicted dose-response curves.