Decreased DNMT3B By RNAi Influences On The Expression Of Its Downstream Genes And Cell Proliferation In HCC Cell Line, SMMC-7721

Objective: To explore the relationship between DNMT3B and hepatocellular carcinogenesis by detecting the expression of DNMT3B in hepatocellular carcinoma cell lines and analyzing tumor-related genes in DNMT3B knocked-down hepatocellular carcinoma cell line.Methods: Real-Time Fluorescent Quantitative RT-PCR was used to detect the expression of DNMTs in normal liver cell line, cell line established from pericarinoma tissue and hepatocellular carcinoma cell lines. Upregulated tumor-related genes induced by DNMT3B RNAi such as SNCG,PDCD4 and MBD3 were also analyzed by Real-Time Fluorescent Quantitative RT-PCR in hepatocellular carcinoma cell lines. The methylation status of SNCG was detected by MSP (Methylated Specific PCR ). The cell cycle and rate of apoptosis were analyzed by Flow Cytometry in DNMT3B knocked-down hepatocellular carcinoma cell lines.Results: In hepatocellular carcinoma cell lines DNMTs is expressed at a high level compared to that in pericacinoma cell line and normal liver cell line, especially DNMT3B. The expression of tumor-related genes such as SNCG, PDCD4 and MBD3 was induced by DNMT3B RNAi in hepatocellular carcinoma cell line and there was no change of methylation status in CpG island of SNCG promoter. The ability of cell proliferation was suppressed and the rate of apoptosis was increased in DNMT3B knocked-down hepatocellular carcinoma cell line.Conclusion: The over-expression of DNMT3B in hepatocellular carcinoma cell lines may be related to hepatocellular carcinogenesis.The repression of DNMT3B induced the expression of some tumor-related genes and influenced the proliferation ability of SMMC-7721 by some ways.