Objective To investigate the expression of histone methyltransferase MLLT3/AF9 in human hepatocellular carcinoma (HCC) tissues and to observe the effect of down-regulation of MLLT3/AF9 expression in vitro on the proliferation and invasion of hepatocellular carcinoma SMMC-7721 cells.

Methods Real-time PCR technique was used to detect the expression of MLLT3/AF9 gene in 100 cases of human hepatocellular carcinoma tissues and adjacent non-cancerous tissues and hepatocellular carcinoma cell lines SMMC-7721, HepG2, Hu7 and BEL-7402. RNA interference was used to reduce the expression of MLLT3/AF9. CCK-8, Transwell assay and scratch test were used to detect the proliferation and invasion abilities of SMMC-7721 cells in MLLT3/AF9 down-regulation group and control group.

Results Real-time PCR results showed that the expression of MLLT3/AF9 in HCC tissues was significantly higher than that in paracancerous tissues. The mRNA and protein expression of MLLT3/AF9 in the experimental group were higher than those in the LV-MLLT3-RNAi group. CCK-8, Transwell assay and scratch test results showed that the proliferation and invasion abilities of SMMC-7721 cells were decreased in LV-MLLT3-RNAi group.

Conclusion The expression of MLLT3/AF9 in hepatocellular carcinoma tissues is significantly increased. The down-regulation of MLLT3/AF9 expression could effectively inhibit the proliferation and invasion of hepatoma SMMC-7721 cells.