Cell lines and cell culture conditions

U87 cells (American Type Culture Collection (ATCC, Manassas, VA), and GS2 cells (a kind gift from Katrina Lamzus at the Hans-Dietrich Hermann Laboratory for Brain Tumor Biology), and normal human astrocytes were purchased from ABM (cat# T0281) were maintained in complete medium consisting of Dulbecco's Modified Eagle Medium (DMEM) supplemented with 10% fetal bovine serum (FBS). GSC 8–18 and GSC 7–2, cells were maintained in DMEM/F12 media supplemented with B27 (Invitrogen), EGF (20 ng/ml), bFGF (20 ng/ml) as previously described [49]. For normoxic conditions, cells were incubated in a humidified chamber at 37°C with 5% CO2. Normal neural stem cells were purchased from ThermoFisher Scientific (Cat# N7800100) and grown in media for glioma stem cells described above. Temozolomide(TMZ) was purchased from Sigma-Aldrich (Cat# T2577) and glumatinase (GLS) inhibitor was purchased from EMD Millipore (Compound 968, cat#352010).