Abstract: AIM: To investigate the mechanism of p16 gene silencing and evaluate the effects of Hydralazine on gastric cancer cell lines in vitro.METHODS: Experimental group BGC-823 cells were treated with 10, 30, 100 μmol/L Hydralazine and control group cells were not treated. After 96 h, methylation specific PCR was used to detect the CpG island methylation state of p16 gene. The expression of p16 gene mRNA and protein were analyzed by RT-PCR and Western blot. BGC-823 cells were treated with six different concentrations of Hydralazine(0, 3, 10, 30, 100, 300 μmol/L)for 72 h, and MTT assay was used to observe the change of proliferation activity.RESULTS: P16 gene promoter region was hypermethylation in control group. P16 mRNA and protein were expressed at a low level in control group. In Hydralazine-treated group, p16 promoter region exhibited a demethylation state, and its mRNA and protein were expressed up-regulation.CONCLUSION: Promoter region hypermethylation is an important mechanism of p16 silencing. Hydralazine, an effective inhibitor of p16 methylation, can inhibit cell growth in human gastric cancer in vitro and be potentially used for the clinical treatment of human gastric cancer.

Key words: Hydralazine, P16, Methylation, Demethylation