5-Aza-dC induced the expression of NGX6 in HT-29 cells. (A) Colon cancer cell line HT-29 was treated with six different doses of 5-Aza-dC (0.625, 1.25, 2.5, 5.0 and 10 μM), as indicated above each lane, for five days. Total RNA was isolated from control, and treated cells were then analyzed by RT-PCR. (B) NGX6 mRNA level was analyzed by real-time PCR after 5-Aza-dC treament. (C). colon cancer cell line HT-29 was treated with 2.5 μM 5-Aza-dC for five days. DNA was isolated and bisulfite-modified, and then analyzed for methylaion of the NGX6 promoter by methylation-specific PCR analysis. "DL": DNA marker 2000; "M": methylated NGX6; "U": unmetylated NGX6.