Influence of silencing Polo-like kinase 1 on migration and invasion of colorectal cancer cells

Abstract

To examine the role of Polo-like kinase 1(PLK1) in the migration and invasiveness of human colorectal cancer cells. Nine colorectal cancer cell lines were cultured. Cell lines with the highest level of PLK1 expression was selected by PCR and Western blot. Three siRNA oligo segments targeting PLK1 were designed and selected cell lines transfected. Successful transfection was confirmed using real-time PCR and Western blot. Changes in migration and invasiveness of the selected cell line were evaluated by Transwell test. Colorectal cancer cell line SW1116 was selected with the highest expression of PLK1 at both mRNA level and protein level. The expression of PLK1 in SW1116 was reduced by the three siRNA oligo segments to varying degrees, and the No.1 siRNA oligo segment was the most efficient. In migration test, the number of cells crossing through chambers in PLK1-siRNA group was 44 ± 14, which was lower than that in the negative control group (242 ± 40) and in blank control group(240 ± 38). In invasion test, the number of cells crossing through chambers in PLK1-siRNA group was 62 ± 3, which was lower than that in negative control group (207 ± 12) and in blank control group (211 ± 15). These differences were statistically significant(P<0.01). PLK1 silencing by siRNA may inhibit the migration and invasiveness of colorectal cancer cells, suggesting that PLK1 might play an important role in the infiltration and metastasis of colorectal cancer.