The estrogen-dependent human breast adenocarcinoma, MCF-7 was obtained from American Type Culture Collection (ATCC, USA). The cells were maintained in Dulbecco’s modified eagle medium (DMEM) (Sigma, USA) supplemented with 10% (v/v) of heat-inactivated foetal bovine serum (FBS) (PAA, Austria), 100 I.U./ml penicillin and 100 ng/ml streptomycin (PAA, Austria). The cells were cultured at 37°C in a 90% humidified incubator with 5% CO2.