Fig. 1

Establishment of TMZR cell models. The TMZ sensitivities of the parental and TMZ adapted a U-251MG and b U-87MG were determined. Cells cultured in 96-well plate were treated with 0–250 μM TMZ in DMEM media supplemented with 2% FBS. Five days later, cell viability was evaluated spectrophotometrically by standard MTS assay. Cell viability (%) was defined as sample/control × 100%. Conditions without TMZ treatment served as controls. Data of biological quadruplicates were expressed as mean + SD. Significant differences in TMZ sensitivities between parental and TMZR cell lines were calculated using two-tailed Student’s t test. **P < 0.01. Cell cycle profile of c U-251MG and d U-87MG parental and their respective TMZR cell lines were verified by flow cytometry using PI-stained nuclei. The percentage of cells in G1, S and G2 phases is shown. e Similar experiment setup was performed to examine TMZ sensitivities of the patient-derived cell lines. The cell viability (%) was calculated accordingly. Significant differences in TMZ sensitivities between U3008MG and other cell lines were calculated using two-tailed Student’s t test. *P < 0.05; **P < 0.005