For cell culture, leukemia K562 cells were cultured in a
flask in an RPMI 1640 medium (GIBCO) supplemented with
10% fetal calf serum (FCS, Sigma), penicillin (100 mU mL−1)
and streptomycin (100 mU mL−1) at 37 ◦C in a humidified
atmosphere containing 5% CO2