Figure 3.

Regulation of CPS1 expression by DNA methylation in HCCs. A: The reactivation of CPS1 gene expression by a demethylation agent in liver cancer cell lines. LH86 and Huh7 were treated with or without Aza, and CPS1 expression was examined by RT-PCR. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as an internal control of the RT-PCR for normalization. B: Methylation-specific PCR analysis of CPS1 promoter in liver cancer tissues. M indicates methylated specific reaction; U, unmethylated specific reaction; C1, unmethylated control human DNA; C2, methylated control human DNA. C through E: Genomic DNA extracted from normal primary hepatocytes (ie, Hu676 and Hu786) and tumor cells (ie, Huh7 and LH86) was modified with sodium bisulfate, followed by PCR amplification, cloning, and sequencing. The DNA methylation status at each CpG site within three regions is shown. Methylated sites are indicated by filled dark circles; and unmethylated sites, empty white ones.