Knockdown of β-catenin by siRNA influences proliferation, apoptosis and invasion of the colon cancer cell line SW480.

The aim of the present study was to explore the effect of knocking down the expression of β-catenin by small interference (si)RNA on the activity of the Wnt/β-catenin signaling pathway, and the proliferation, apoptosis and invasion abilities of the human colon cancer cell line SW480. For that purpose, double-stranded siRNA targeting β-catenin (β-catenin-siRNA) was synthesized and transfected into SW480 cells. Reverse transcription-polymerase chain reaction (RT-PCR) and western blotting were used to detect the messenger (m)RNA and protein levels of β-catenin in SW480 cells. To detect cell proliferation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed, while cell apoptosis and caspase-3 activity were detected by flow cytometry and caspase-3 activity assay, respectively. Matrigel invasion assay was performed to detect the influence of siRNA-mediated gene silencing on the invasion and metastasis of SW480 cells in vitro. The results of RT-PCR and western blot analysis demonstrated that, compared with the blank control, negative control and liposome groups, β-catenin-siRNA transfected SW480 cells had significantly decreased mRNA and protein levels of β-catenin. In addition, following β-catenin-siRNA transfection, the proliferation of SW480 cells was significantly lower than that of the blank control, negative control and liposome groups, while the apoptosis rate increased in β-catenin-siRNA transfected cells, compared with the aforementioned groups. Invasion assay showed that, following β-catenin-siRNA transfection, the number of SW480 cells infiltrating through the Matrigel membrane was significantly lower than that of the blank control, negative control and liposome groups. Following β-catenin-siRNA transfection, the caspase-3 activity in SW480 cells was lower than that in the blank control, negative control and liposome groups. These results indicate that siRNA-mediated silencing of β-catenin could inhibit the proliferation and invasion of SW480 cells and induce apoptosis, thus providing novel potential strategies for the clinical treatment of colon cancer, and may serve as a novel target for cancer therapy.