Gefitinib Radiosensitizes Stem-Like Glioma Cells: Inhibition of Epidermal Growth Factor Receptor-Akt-DNA-PK Signaling, Accompanied by Inhibition of DNA Double-Strand Break Repair

Stem-like gliomaspheres are resistant to irradiation-induced cytotoxicity, G2/M arrest, and DNA DSBs, compared with nonstem glioma cells. Gefitinib differentially enhances radiosensitivity of stem-like gliomaspheres by reducing EGFR-Akt activation and DNA-PKcs expression, accompanied by enhanced irradiation-induced DNA DSBs and inhibition of DSB repair.