Drug-induced loci-specific and global demethylation. (A) MSP was applied to determine the methylation level of Trip10 and GSTp1 in MCF7 cells treated with each of the following derivatives at 7.5 or 30 μM: procainamide, 5-Aza, IM25, IM9, CI-4-1, CI-5-1, 4e, and 4o, after 5 days of treatment. Procainamide, 5-Aza, IM25, CI-4-1 and 4e significantly reduced the methylation level of GSTp1, while they appear to have weaker effect in demethylating Trip10 promoter (B) DMH analysis of the effect of 7.5 μM IM25 on genome-wide methylation. The higher Log2[Cy5/Cy3] values indicate stronger demethylation effects. (C) Genome-wide comparison of the demetylation after IM25 and 5-Aza treatment. DMH microarrays identified 5,506 more loci that are demethylated after IM25 treatment (open circles) than the result obtained after 5-Aza treatment (close gray circles). The regressed lines depicted the distribution of demethylation (dashed line for 5-Aza; solid line for IM25) and all the listed 5,506 loci were confirmed significant by ANOVA.