Objective: To investigate the effects of the DNA methyltransferase inhibitor 5-Aza-2'-
Deoxycytidine (5-Aza-Dc) on DLC-1 gene expression, methylation level, and the expression of
downstream signaling molecules Cdc42 in the human multiple myeloma cell line RPMI8226 cells.
Methods: The RPMI8226 cells were treated with 5-Aza-Dc, the methylation status of CpG island of
DLC-1 gene was detected by bisulfate sequencing PCR(BSP) in RPMI8226 cells. The expression of
DLC-1 and Cdc42 mRNA was determined by reverse transcriptase polymerase chain reaction (RT-PCR).
Enzyme-linked immunoabsorbent assay (ELISA) was used to detect the expression of Cdc42 protein.
Results: The methylation of DLC-1 gene was detected in the RPMI8226 cells without 5-Aza-Dc pretreament. DLC-1 gene
methylation status was decreased after the 5-Aza-Dc treatment for 72h, and DLC-1 gene didn't display DNA methylation
on the highest concentration of 5-Aza-Dc. DLC-1 mRNA was weakly expressed in the control group, and the expression
was gradually increased in 5-Aza-Dc treatment group. The Cdc42 mRNA and protein expression of experimental group
were significantly decreased and were dose-dependent compared with the control group (P <0.05).
Conclusion: The results of this research indicated that 5-Aza-Dc can effectively inhibit the methylation status of DLC-1
gene, reversal DLC-1 gene expression, and significantly decrease the expression of downstream signaling molecules
Cdc42 mRNA and protein in RPMI-8226 cell.