Abstract:

Objective  To investigate the effect of DNA methylation inhibitor 5-Aza-2′-deoxycytidine (5-Aza-CdR) on transcription regulation of SOCS-1 gene and the molecular biological behaviors in RPMI8226 cells. Methods  The RPMI8226 cells were treated with different doses of 5-Aza-CdR，  and MTT was used to detect the proliferation of RPMI8226 cells. The apoptosis and cell cycle were analyzed by flow cytometry.  Real-time PCR was used to examine expression of the SOCS-1 gene.  Results   5-Aza-CdR significantly inhibited  cell growth in dose and time dependent manners（P<0.05）.5-Aza-CdR increased the apoptosis rate of RPMI8226 cells as well as  in a dose-dependent manner. The apoptosis rates of RPMI8226 cells treated with 5-Aza-CdR at concentration of 0.1,0.5,,1.0,2.0,5.0μmol/L for 72 hours were （29.62±2.87）%,（39.98±2.53）%,（49.07±3.51）%,（60.15±4.54）and（69.88±3.49）% respectively. After treatment with different concentrations of 5-Aza-CdR for 72h, cells were arrested in G (0)/G (1) phase in contrast to the control group (P<0.05).  Real-time PCR results showed that there were few SOCS-1 genes expressed in RPMI8226 cells after treatmean with 5-Aza-CdR for 72h,  and expression level of SOCS-1 was increased significantly in a concentration-dependent manner(P<0.05). Conclusion  5-Aza-CdR could narkedly inhibit the proliferation of RPMI8226 cells and induce cell apoptosis, which might be related to demethylation and reexpression of the SOCS-1 gene in RPMI8226 cells.

Key words:  DNA methylation; 5-Aza-2′-deoxycytidine; Suppressor of cytokine signaling 1; Multiple myeloma