Fig. 4.

Salinomycin targets the radioresistant stem cell–like population. (A) Intact, condensed, and fragmented nuclei (4′,6′-diamidino-2-phenylindole blue) were assessed 24 hours post-DMSO versus post-Sal (10 µM) treatment, quantitation (right). (B) Flow cytometry was performed to determine cell death following Sal treatment (10 µM) with ± IR (2 Gy). (C) Immunoblot was performed to determine MCL-1 protein expression following Sal (10 µM) with ± IR (2 Gy) treatment. (D) CFSE was used to track cell division, GNS cells were treated with Sal (10 µM) ± IR (2 Gy) and allowed to recover for 72 hours prior to labeling. Cell division was assessed 96 hours later. (E, F) WK1-luc tumor cells were isolated from orthotopic xenografts at day 60 and received Sal (10 µM) with ± IR (2 Gy) treatment for 72 hours prior to CD133 flow cytometric expression analysis as indicated; CD133 expression was assessed during treatment (treated) and after Sal had been removed for 96 hours (recovery). Neurosphere formation was assessed 7 days post-treatment withdrawal as indicated. Statistical significance: **P < 0.01, ***P < 0.001.