Culturing of Human Glioblastoma Cell Lines

The human GBM cell lines U87 and T98G,^{15 (link)} as well as HEK293 cells (all from ATCC), were maintained according to the vendor’s specifications. Primary GBM cells were cultured in MACS Neuro Medium (Miltenyi), supplied with 2% MACS Neuro Brew-21 w/o Vit. A (Miltenyi), 10% FCS, 2% Penicillin-Streptomycin, and 2% l-Glutamine. HUVECs were cultured in 200PRF (Thermo Fisher) with 2% LSGS (Thermo Fisher). All cell lines were cultured at 37°C, 5% CO₂ in a tissue culture incubator (Heraeus). For experiments under hypoxic conditions, cells were incubated in 5% O₂ and 40 mmHg CO₂ in an air-tight hypoxia chamber (Billups-Rothenberg) at 37°C. For stimulation experiments, cells were incubated with supernatant of stimulated PBMCs or IL-1β (10 ng/mL, Miltenyi) for 24 h. Unstimulated controls were present in all stimulation experiments (Supplementary Figure S2).