The Study On The Promoter CPG Islands Methylation Status Of NFAT2 Gene In Hepatocellular Carcinoma

Objective The high prevalence and low survival rate of Hepatocellular carcinoma(HCC)is a serious hazard to human health.In the exploration of effective early diagnosis and molecular targeted therapy of liver cancer,the understanding of its molecular mechanism of cancer is indispensable.Some studies have shown that the nuclear factor of activated T cells(NFAT)family is involved in the development and progression of tumor.The difference of expression of NFAT2 gene in hepatocellular carcinoma and adjacent tissues is the largest,decreasing in cancerous tissues.This paper explores the mechanism of NFAT2 gene decreased expression in HCC from the perspective of epigenetics,and explores the methylation status of CpG island in the promoter region of this gene.And to further verify the effect of methylation on NFAT2 gene expression.Methods The fluorescence quantitative polymerase chain reaction(qRT-PCR)and Western Blot(WB)were used to examine the mRNA and protein of NFAT2 in tissues.The promoter CpG islands methylation status of NFAT2 in HCC and corresponding adjacent non-tumor tissues and liver cell lines was examined by Bisulfite sequencing PCR(BSP).The methylation status of NFAT2 promoter and its effect on the expression of NFAT2 were further investigated by the cell addition assay with 5-aza-dC.Results The expression of NFAT2 in HCC was lower than that in corresponding adjacent non-tumor tissue(P<0.05).The promoter CpG islands methylation percentage of NFAT2 gene in HCC was significantly more than that in corresponding adjacent non-cancerous liver tissues(33.0%±13.9% VS.21.6%±8.3%)(P=0.003).The promoter CpG islands methylation percentage of NFAT2 in HCC cell lines(HuH7,HepG2 and Hep3B)was also significantly more than that in human normal liver cell line(L02)(34.8%±7.3%,40.4%±10.3% and 37.0%±10.1% VS.16.2%±6.9%)(P<0.01).Spearman correlation analysis revealed there is negative association between the NFAT2 mRNA level and the promoter methylation(r =-0.661,P=0.027).The expression of NFAT2 in PLC with 5-aza-dC(experimental group)is higher than PLC with DMSO(control group)(P<0.05).Conclusions The promoter of NFAT2 gene in hepatocellular carcinoma is hypermethylated,and the methylation may contribute to gene low expression.