Fig. 6 .

Elevated sensitivity of TMZ-resistant GSC lines to radiation. Individual (A) and averaged (B) relative (%) changes in surviving TMZ-sensitive (1123ICS, white bars) and TMZ-resistant (1123ICR, black bars) cells after exposure to 0, 2, 4, 6, and 8 Gy of radiation therapy in vitro. TMZ-resistant cell lines exhibit greater cytotoxic impact. (C–E) Impact of radiation (2 Gy) on tumor forming potential of TMZ-sensitive and -resistant GSCs. Pre-irradiated cells were injected into NSG mice. (C) Tumor volume after 26 days of growth. (D, E) Tumor growth curves of TMZ-sensitive (D) or TMZ-resistant (E) GSC lines treated (grey symbols) or not (white or black symbols) with radiation. ****P < 0.0001; **P < 0.01; *P < 0.05 (N = 3).