FIGURE 7. Decitabine and trichostatin A synergistically activate transiently transfected methylated rDNA promoter, but exhibit an additive effect on the unmethylated promoter.

A, HCT cells were treated with 50 nm Decitabine for 24 h followed by 100 nm TSA for an additional 12 h. Total RNA was treated with DNase I before cDNA synthesis. An aliquot of cDNA was subjected to real time PCR analysis with primers specific for 47 S rRNA and 18 S rRNA. RNA without reverse transcription did not generate PCR product. B, HeLa cells were transfected with mock methylated or methylated pHrD-IRES-Luc and split into four dishes 24 h after transfection. The cells were either left untreated or treated with 1 μm Decitabine (D) for 12 h followed by treatment with 100 nm TSA for 12 h (D/T) or TSA alone (T) for 12 h. Cells were harvested and luciferase activity was measured in the cell lysate. Results are represented as hours of DNA promoter activity/μg of protein.