Effect Of 5-Aza-2'-deoxycytidine On Human Gastric Carcinoma Cell Lines With Analysis Of Suppressive Role Of RASSF1A Gene

Objective:To observe the effects of specificity methyltransferases inhibitor 5-aza-2'-deoxycitydine (5-Aza-CdR) on the proliferation of human gastric cancer cell lines BGC823,SGC7901 and MKN-28as well asd epression of RASSF1A gene.Methods:Human gastric cancer cell lines BGC823,SGC7901 and MKN-28 were cultured in RPMI1640 and then treated with different concentrations of 5-Aza-CdR (0.4,1.6,6.4,25.6,102.4μmol/L). The proliferation of the cells was detected by MTT assay and flow cytometry(FCM). the expression of RASSF1A gene in the three kinds of cell lines was detected by reverse transcription-polymerase chain reaction (RT-PCR).Result:5-Aza-CdR displayed a growth inhibitory effect on BGC823,SGC7901 and MKN-28 cells in a dose- and time-dependent manner after exposure to 5-Aza-CdR at different concentrations(0.4,1.6,6.4,25.6,102.4μmol/L)for 24,48 and 72 hours. FCM analysis showed that the apoptosis rates in BGC823 cells (2.4%±0.26%,2.8%±1.19%,4.6%±0.86%,10.1%±0.86%,26.3%±1.4%),SGC7901 cells (14.2%±1.05%,15.7%±0.60%,8.4%±1.00%,19.3%±0.91%,41.6%±1.73%,) and MKN-28(3.10%±1.66%,3.46%±2.15%,3.70%±0.55%,8.43%±2.31%,27.3%±3.60%,) were increased significantly after exposure to 5-Aza-CdR 0.4,1.6,6.4,25.6,102.4μmol/L) for 72 hours as compared with 0.8%±0.03%,9.3%±1.22% and1.30%±0.96% in the control cells (P < 0.05). After 5-Aza-CdR treatment, the number of G0/G1 cells was increased, and 5-Aza-CdR blocked the cell cycle at G1 phase except BGC-823. RASSF1A gene was reactivated by 5-Aza-CdR in gastric cells(SGC-7901,MKN-28) not expressing RASSF1A,RASSF1A gene was always expression no matter weather treating with 5-Aza-CdR in BGC-823.Conclusion:5-Aza-CdR can inhibit the proliferation of BGC823,SGC7901 and MKN-28 cells ,and inducing the apoptosis of gastric carcinoma cell (SGC7901,MKN-28)lines by eliminating the methylation status of RASSF1A promoter.