Mahanine restores RASSF1A expression by demethylating its promoter and all three DNMTs control RASSF1A expression. A. PC3 cells were treated with DMSO control or 10 μM mahanine for 1 and 3 days. Methylation-specific PCR was performed to detect the methylated (M) and un-methylated (UM) status of RASSF1A promoter. B. PC3 cells were treated with DMSO control or 10 μM mahanine for 1 and 3 days, following which RASSF1A expression was assessed by RT-PCR. GAPDH was used as an internal control. C. PC3 cells were transfected with shRNA for DNMT1, DNMT3A, DNMT3B or scrambled shRNA. Forty-eight hours after transfection, cells were harvested for RT-PCR analyses to assess RASSF1A expression. GAPDH was used as an internal control. For DNMT3A, two shRNAs were used to confirm the result. D. BPH1 cells were transfected with expression vectors of DNMT1, DNMT3A, DNMT3B or empty vector control. Forty-eight hours after transfection cells were collected for RT-PCR analyses to determine RASSF1A, DNMT1, DNMT3A and DNMT3B expression levels. GAPDH was used as an internal control.