OBJECTIVETo study the promoter methylation status of SFRP genes and the effect of 5- aza- 2'- deoxycytidine (5- Aza- CdR)induced apoptosis via Wnt/β- catenin pathway by demethylation in Jurkat cells.

METHODSJurkat cells were treated with different concentrations of 5- Aza- CdR. The cell proliferation level of Jurkat cells was detected by MTT assay. Apoptosis was evaluated by flow cytometry. Methylation- spcific PCR (MSP) was used to determine the methylation status of SFRP genes. The expressions of SFRP genes were detected by real time fluorescence quantitative PCR. The mRNA expression levels of survivin, c- myc and cyclin- D1 were analyzed by RT- PCR. Western blot was used to detect the levels of β-catenin protein.

RESULTSCompared with control group, the different concentrations of 5-Aza-CdR could significantly inhibit the proliferation of Jurkat cells in a time-dose dependent manner (P<0.05). After being treated by 5- Aza- CdR for 48 hours, the cell early apoptosis rate in experiment group was significantly higher than that in control group (P<0.05). The promoters of SFRP1, SFRP2, SFRP4, SFRP5 genes were hypermethylation state in the control group, after being treated by 5-Aza-CdR for 72 hours, the brightness of SFRP1, SFRP2, SFRP4, SFRP5 genes' methylation strips weakened in a dose- dependent manner. SFRP mRNA expression increased (P<0.05) when 5- Aza- CdR concentration increased, and the level of β- catenin protein was dampened in a dose- dependent manner (P<0.05). As compared to the control group, the mRNA expressions of associated apoptosis genes survivin, c-myc and cyclin- D1, respectively were obviously down- regulated in a dose- dependent manner (P<0.05).

CONCLUSIONThe effect of demethylation could up- regulate SFRP genes expressions by reversing its hypermethylation and induced apoptosis by down-regulation of β-catenin and associated apoptosis genes.