OBJECTIVETo explore the effect of Cortactin on invasion and metastasis of human colorectal cancer cells through silencing the expression of Cortactin by transfecting colorectal cancer cells with EMS1-siRNA encoded by a recombinant lentiviral vector.

METHODSEMS1-siRNA lentiviral vector and negative control lentiviral vector were both transfected into HCT8 cells after virus packing, then the expression of Cortactin of the cells was examined by Western blot to determine the inhibited level of Cortactin. The cells were defined as three groups: EMS1-siRNA transfecting cells, negative control transfecting cells and un-transfection cells. Cell invasion was evaluated with Transwell body. In addition, cells metastasis was observed in animal models. Thirty nude mice were evenly divided into three groups and all the mice were injected through tail vein with 1×10(7) cells/0.2 ml per animal for each group with the three kinds of cells. The mice were sacrificed 6 weeks after injection and examined for lung metastases development.

RESULTSThe expression of Cortactin and the ability of invasion of the EMS1-siRNA transfecting cells were all decreased. Lung metastasis rates of EMS1-siRNA transfecting group, negative control group and un-transfection group were 20%, 80% and 80%, respectively.

CONCLUSIONsiRNA silencing of Cortactin expression can decrease the colorectal cancer cells invasion, and can also decrease the cells' implantation metastasis in animals.