4.1. Cell Culture

HeLa, U2OS and MEF cells were cultured in Dulbecco’s modified Eagle’s medium (DMEM, Gibco, Waltham, MA, USA) supplemented with 10% fetal bovine serum (Sigma, St. Louis, MO, USA), 2 mM L-glutamine, 100 U/mL penicillin and 0.1 mg/mL streptomycin (all PAN Biotech). Cells were grown at 37 °C and 5% CO₂. Where indicated, cells were treated with ASN (NaAsO₂, Sigma) or NaN₃ (AppliChem, Omaha, NE, USA). During treatment and 2h before treatment, cells were cultivated in DMEM with 1g/l D-Glucose (low-glucose) (Gibco). In parallel, control cells were kept in a low-glucose medium without NaN₃.