Culture and Maintenance of Glioblastoma Cell Lines

U87 and U251 glioblastoma cell lines (identity of cell lines was verified by karyotyping and STR profiling) were obtained from ECACC and were cultured in DMEM cell medium (DMEM-HA, Capricorn Scientific, Ebsdorfergrund, Germany) supplemented with 10% fetal bovine serum (FBS) (S0615, Sigma, Dreieich, Germany), 1% penicillin/streptomycin (2321115, Gibco, Carlsbad, CA, USA), 1% Non-essential amino acids (NEAA) (11140050, Gibco, Carlsbad, USA) and 1% Sodium pyruvate (NPY-B, Capricorn Scientific, Ebsdorfergrund, Germany). Glioblastoma stem-like cells were isolated as described previously [12 (link)]. Cells were cultured in DMEM/F12 medium (DMEM-12-A, Capricorn Scientific, Ebsdorfergrund, Germany) including 2% B27 supplement (117504044, Gibco, Carlsbad, USA), 1% amphotericin (152290026, Gibco, Carlsbad, USA), 0.5% HEPES (H0887, Sigma, Dreieich, Germany) and 0.1% gentamycin (A2712, Biochrom, Berlin, Germany) with EGF (100-18B, Peprotech, Hamburg, Germany) and bFGF (315-09, Peprotech, Hamburg, Germany) in a concentration of 20 ng/mL, respectively. All cells were incubated at 37 °C under 5% CO₂ humidified incubator.