Effect of decitabine combined with daunorubicin on apoptosis of HL-60 cell line

Objective To observe the cell proliferation inhibition of DNA methyltransferase (DNMT) inhibitors decitabine (DAC) combined with daunorubicin (DNR) in human leukemia cell line HL-60.Methods The effects of DNR and DAC were examined in HL-60 cells by cell viability using MTT method,and cell death using flow cytometric (FCM).Results DAC,DNR single drug application showed their effects on cell proliferation was dependent of dose and time,the inhibition effect of combined treatment group was much clearer [inhibition ratio of 72 hours was (80.23±1.71) ％,P ＜ 0.001].The highest apoptosis rate was at 5.0 μmol/L DAC combined with 1.0 μmol/L DNR for 72 hours,which was statistic significant (F =30.199,P ＜ 0.001).Combinations of different concentrations of DAC and DNR increased expression of PTEN mRNA in concentration-dependent manner,which was significantly higher than the control group and DNR single drug group (F =578.218,P ＜ 0.001).Conclusions DAC can significantly inhibit the proliferation of HL-60 cells and induce apoptosis,synergistic effect can be observed when DAC combined with DNR.The underlying mechanism can be due to DAC demethylation effect to increase PTEN mRNA expression. Key words: 5-Aza-2'-deoxycytidine;  Daunorubicin;  HL-60 cells;  Apoptosis;  PTEN