Fig. 6
Glimepiride disrupts GSC maintenance and glycolytic activity by CLIP3 activation. A mRNA levels of CLIP3, NANOG, and OCT4 were analyzed by real-time qRT-PCR upon treatment of IR (6 Gy), IR with Kir6.2 siRNA, IR with glimepiride (1 μM), or IR with glibenclamide (1 μM) in U87MG and T98G cells. B IC50 of glimepiride with or without IR in U87MG and T98G cells was measured by CellTiter-Glo® Luminescent Cell Viability Assay. Cells were treated with increasing concentrations of glimepiride and/or IR (6 Gy) for 48 h. C Colony-forming ability was evaluated using colony-forming assay after treatment of glimepiride (0.1 and 1 μM) with or without IR (6 Gy) (data represent mean of n = 3 dishes). D In vitro limiting dilution assays of GSC11, BCL20-HP01, and BCL20-HP02 cells treated with glimepiride (1 μM) or glimepiride with CLIP3 siRNA. The frequency of GSCs was calculated by extreme limiting dilution assay (ELDA) analysis. E ECAR was measured by Seahorse analyzer upon treatment of glimepiride (1 μM) (upper panel), and treatment of CLIP3 siRNA with or without glimepiride (lower panel) in GSC11, BCL20-HP01, and BCL20-HP02 cells. Statistical analysis was performed with one-way ANOVA plus a Tukey’s multiple comparisons test for (A) and (C), and Student’s t-test for (E). *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 (compared to control). #p < 0.05, ##p < 0.01, ###p < 0.001, ####p < 0.0001 (compared to IR)