Cell Culture. Cells (HaLa) were cultured in Dulbecco's modified Eagle's medium (DMEM;Sigma) supplemented with 10% fetal bovine serum (FBS) in T25 culture flasks (Nunc, Denmark) and were incubated at 37 ํc in a humidified atmosphere containung 5% co2 Cells were regularly passaged by trypsinization with 0.1% trypsin (EDTA 0.02%, dextrose 0.05%,and trypsin 0.1%) in PBS (pH 7.2).