The effect of 5-Aza-CdR on TIMP-3 gene in hepatocellular carcinoma cells

Objective The aim of this study is to investigate the CpG island methylation status of TIMP- 3 in HCC cell lines, to treate the HCC cells that exhibit positive methylation with DNA methyltransferase in- hibitor(5-Aza-CdR), and to observe the influence of 5-Aza-CdR on the expression of TIMP-3 mRNA and its CpG island methylation degree. Methods TIMP-3 CpG methylation status of HCC cells were examined using MSP assay. Methylation-positive HCC cells were treated with DNA methyltransferase inhibitor(5-Aza- CdR)(intervention group), and the difference of TIMP-3 mRNA expression was observed between interven- tion group and control group. Pyrosequencing method was applied to quantitatively examine the CpG island methylation percentage. Results The methylation of TIMP-3 CpG islands in C3A, HepG-2, and Hep-3B was positive. The results showed that TIMP-3 mRNA expression was increased(P 0.05) and the methylation level was decreased(P 0.05) in the intervention group compared to control group. Conclusion 5-Aza-CdR could remarkably reduce the level of the CpG island methylation and increase the expression of TIMP-3 mR- NA in HCC cells.