2.2 Cell culture
The U87 MG (HTB-14™) human glioma cell line was purchased from ATCC (American Type Culture Collection). The U87 cells were cultured in DMEM medium (Dulbecco’s modified Eagle’s medium, Roswell Park Memorial Institute), 10% fetal bovine serum (FBS/ Sigma Aldrich, St. Louis, MO), 1% Penicillin/Streptomycin (Pen/Strep, Pan Biotech, Germany). We used the 75 cm2 cell culturing flasks (TTP, Switzerland) at 37˚C with 5% CO2 (NUVE, Turkey).