Objective  The objectives of this study were to explore the inhibitory effect of Slug gene silencing on the proliferation and invasion ability of the colon cancer cell line HCT116 and investigate its influence on E-cadherin expression.

  Methods   Three siRNA plasmids, namely, pGenesi-1/Slug siRNA 1-3, and pGenesi-1 negative control (NC) were transfected into the HCT 116 cell line using Lipofectamine 2000. RT-PCR and immunoblotting were used to observe the inhibitory effect of Slug siRNA on slug mRNA and protein expression. After the sequence of the plasmid with the best interfering effects was screened and when it was transfected into HCT 116 cells, MTT assay was used to detect cell proliferative activity and cell wound healing, whereas transwell assay was adopted to investigate cell migration and invasion ability. E-cadberin mRNA and protein levels were also investigated when Slug expression was inhibited in HCTll6 cells.

  Results   Transfection of the three Slug plasmids, of which Slug siRNA3 showed the best interference effects, effectively inhibited the expression of Slug. Compared with the NC group, the mRNA and protein expression levels of Slug decreased by 85% and 80%, respectively. The growth rate of HCT 116 cells in the Slug siRNA3 group was significantly lower than that in the NC group (P < 0.05), as were the healing rates and average number of cells that invaded the Matrigel gel in the Slug siRNA3 group (P < 0.05). Moreover, inhibition of Slug expression sig- nificantly increased the E-cadherin mRNA and protein expression levels.

  Conclusion   Knockdown of Slug expression can inhibit the proliferation and invasion ability of colon cancer cells, and its mechanism of action is potentially related with the upregulation of E-cadherin.