Effects of the NL and RUX combination on primitive and quiescent (CFSE^max) CML and normal CD34⁺ cells. (A) CML and (B) normal CD34⁺ cells (n = 3) were stained with CFSE and either left UT, or treated with NL (5 µM) or RUX (200 nM) or their combination, and cultured. At 72 hours, the percentage of starting CD34⁺ cells recovered within each division in each treatment arm was calculated by recording the number of viable cells seeded initially in each culture and their number following different treatment conditions. Levels of CFSE fluorescence was used to measure the percentage of cells within each division as explained previously.³²  (C) Percentage of total number of starting CML, and (D) normal CD34⁺ cells recovered in each arm following treatment was also recorded at 72 hours. Percentage of apoptotic cells within the undivided (CFSE^max) population was measured by gating on the population double-positive for maximal CFSE expression, and Annexin-V staining at 72 hours for both (E) CML and (F) normal CD34⁺ cells. (G) Sorted CML, BCR-ABL⁺ (by FISH) CD34⁺ CD38⁻ cells (n = 3) were cultured as in (A) for 72 hours. Percentage of viable cells was measured by gating on the double-negative population following Annexin-V/DAPI staining. The results were then normalized against UT within each sample. All data from independent experiments are presented as mean ± SEM. Significance values: *P < .05; †P < .01; ‡P < .001.