Wip1 gene silencing enhances the chemosensitivity of human colon cancer cells.

Abstract

Colon cancer is one of the most common cancers in the world. Multidrug resistance is one of the main reasons for failure of therapy in patients with advanced colon cancer. In previous studies, multiple methods were investigated to reverse the multidrug resistance of colon cancer cells. However, to date, no clinical method has been identified to be satisfactory. Therefore, successful reversal of drug resistance in colon cancer cells still requires new therapeutic strategies or pharmaceuticals. Wild-type p53-induced phosphatase (Wip1), a member of the 2C type serine/threonine protein phosphatase family, is closely associated with the p53 gene, which is the most important tumor-suppressor gene. Wip1 was reported to be associated with the chemosensitivity of breast cancer cells. However, the correlation between the expression of Wip1 gene and the chemosensitivity of colon cancer cells has not been reported yet. In the present study, Wip1-811 small interfering RNA (siRNA) targeting Wip1 was investigated to reverse the multidrug resistance of colon cancer cells. The siRNA duplexes were transfected into RKO colon cancer cells. The messenger RNA (mRNA) expression of Wip1 was measured by reverse transcription-quantitative polymerase chain reaction. The protein level of Wip1 was detected by western blotting. The cell viability was measured by MTS assay. The cell apoptosis and cell cycle were analyzed by flow cytometry. Intracellular adriamycin cumulative concentration was determined using flow cytometry. Wip1-811 siRNA efficiently inhibited the expression of Wip1 at the mRNA and protein levels, and enhanced the sensitivity of RKO colon cancer cells towards chemotherapy, which was accompanied by increased cell apoptosis, following the inhibition of Wip1 gene expression. These results indicate that Wip1 gene silencing could enhance the chemosensitivity of colon cancer cells, which may provide a new potential approach for the reversal of multidrug resistance in colon cancer cells.