Figure 5. Treatment with ABT-737 increases X-ray-induced apoptosis of the SP+/CD44^high/ALDH^high cells sub-population.

A SP⁺/CD44^high/ALDH^high sub-population sorted from the SQ20B cell line was treated with DMSO 0.1% (Control: Ctr) or 10 μM ABT-737 20 h before a 10 Gy irradiation. 24 h, 48 h, 72 h and 120 h after irradiation, (A) the percentage of sub-G1 cells and (B) the loss of mitochondrial outer membrane potential (ΔΨm) were measured by flow cytometry analysis. (C) The expression of Bcl-2 family proteins in the SP⁺/CD44^high/ALDH^high sub-population was performed by Western blot analysis, 7 hours and 24 hours after irradiation, respectively. Tubulin is shown as a loading control. Blots are representative of three independent experiments ***p < 0.001.