Figure 1

Effect of DAC concentration on DNA methylation and reactivation of p57 and p16 tumor suppressor genes. A), HL-60 cells were treated with the indicated concentrations of DAC for 48 h. Total DNA was isolated at 72 h and the LINE-1 element gene methylation status was analyzed by COBRA assay. B), HL-60 cells were treated with the indicated concentrations of DAC for 48 h and total RNA was isolated at 72 h. Gene expression of 18 S ribosomal RNA gene and p57 were analyzed by RT-PCR. The amount of DNA amplified during the exponential phase of PCR was analyzed by quantification of amplified DNA by an Agilent 2100 Bioanalyzer. The control cells are HL-60 with no drug treatment. Control vs DAC 100 ng/ml or 1,000 ng/ml p < 0.001. C), Calu-6 cells were treated with the indicated concentrations of DAC for 48 h. Total RNA was isolated at 72 h and 18 S ribosomal RNA gene and p16 gene expression analyzed by RT-PCR. The amount of DNA amplified during the exponential phase of PCR was analyzed by quantification of amplified DNA by an Agilent 2100 Bioanalyzer. For the quantitative detection of gene expression, we used 18S as the reference to normalize the data. The control cells were Calu-6 with no drug treatment. Control vs DAC 100 ng/ml p < 0.01. Data are mean values ± S.D., n ≥ 3.