Fig. 5: Lidoflazine increases the radiosensitivity of GBM cell lines.

a qRT‒PCR analysis of nrbf2 mRNA levels after irradiation and lidoflazine treatment in a GBM cell line. b Western blot analysis to evaluate autophagic flux after irradiation and treatment of lidoflazine in U-87 MG cells. c Autophagic flux analysis using the mCherry-EGFP reporter. U-87 MG and A172 cells transfected with mCherry-GFP-LC3B were treated with IR (3 Gy), lidoflazine (1 μM), or both for 24 h. The mean number of autophagosomes and autolysosomes are represented by yellow and red dots, respectively, in the merged images. The images were quantified using ImageJ (n = 5). Scale bars, 10 µm. d Percentage of GBM cells stained positively for the Ki67 proliferation marker with different treatments. Differences among means were statistically significant, according to a t test. e Clonogenic assay after IR (3 Gy), lidoflazine (1 μM), or both in U-87 MG cells cultured in low glucose media containing 1 mM glucose. Representative images of single-cell clone proliferation stained with crystal violet. f IC₅₀ of lidoflazine with or without IR in U-87 MG cells was measured by CellTiter-Glo® Luminescent Cell Viability Assay. Cells were treated with increasing concentrations of lidoflazine and/or IR (3 Gy) for 48 h. g Clonogenic assay after IR (3 Gy), lidoflazine (1 μM), or both in ATG7 knockout U-87 MG cells cultured in low glucose media containing 1 mM glucose. Representative images of single-cell clone proliferation stained with crystal violet. h Transwell migration assay (upper) and invasion assay (lower) of U-87 MG cells cultured in low glucose media containing 1 mM glucose with treatment with lidoflazine (1 μM), IR (3 Gy), or both. i U-87 MG cells in a three-dimensional culture system were stained with α-tubulin (green) and DAPI (blue). Scale bars, 10 µm. *p < 0.05, ***p < 0.001, ****p < 0.0001 using an unpaired t test.