Effect of 5-Aza-2'-deoxycytidine on biological behaviors of human breast cancer cell line MCF-7

OBJECTIVE:To explore the effect of methylation inhibitor 5-Aza-2'-deoxycytidine(5-Aza-CdR)on the growth of human breast cancer cell line MCF-7,and to investigate the possibility of its application in clinical treatment.METHODS:Human breast cancer MCF-7 cells were treated with 0.4,1.6,6.4,25.6 and 102.4 μmol/L 5-Aza-CdR,respectively.Then the growth of the cells were observed by MTT assay.The cell cycle and apoptosis were analyzed by flow cytometry.The expression of the tumor suppressor gene RASSF1AmRNA was detected by reverse transcription polymerase chain reaction(RT-PCR).RESULTS:5-Aza-CdR inhibited the proliferation of MCF-7 cells significantly at a concentration of 1.6 μmol/L for 1 day or at a concentration of 0.4 μmol/L for 3 days(P0.05);after treatment for 3 days,the number cells of G0/G1 phase increased at a concentration of 6.4 μmol/L(P0.05),and the cell cycle was blocked at G0/G1 phase.The apoptosis rate increased significantly to 11.8±0.30% at a concentration of 0.4 μmol/L compared with the control group(P0.01).The effects mentioned above were in a time-and concentration-dependent manner.RASSF1A gene was reactivated by 5-Aza-CdR in MCF-7 cells not expressing RASSF1A.CONCLUSION:5-Aza-CdR can inhibit the growth,and promote the apoptosis of MCF-7 cells by eliminating the methylation status of RASSF1A promoter.