Icariin reduces human colon carcinoma cell growth and metastasis by enhancing p53 activities

Icariin has been reported to possess high anticancer activity. Colon carcinoma is one of the leading causes of cancer-related mortality worldwide. Here, the anticancer activity of icariin against HCT116 colon carcinoma cells and the possible underlying mechanism were studied. The trypan blue staining assay, wound healing assay, clonogenic assay, CCK-8 assay, and Annexin V-FITC/PI double staining method were carried out to determine the changes of HCT116 cell growth and migration. mRNA and protein expressions were determined by quantitative real-time PCR and western blot, respectively. Moreover, small interfering RNA (siRNA) plasmid was used to examine the role of p53 in icariin-induced apoptosis in HCT116 cells. Icariin significantly suppressed colon carcinoma HCT116 cells by decreasing migration and viability, and simultaneously promoting apoptosis. Icariin exerted the anti-tumor effect in a dose-dependent manner by up-regulating p53. During treatment of icariin, p-p53, p21, and Bax levels increased, and Bcl-2 level decreased. Short time treatment with icariin induced DNA damage in HCT116 cells. Furthermore, the cytotoxicity of icariin was decreased after p53 knockdown or by using caspase inhibitors. p53 was involved in activities of caspase-9 and caspase-3. Icariin repressed colon carcinoma cell line HCT116 by enhancing p53 expression and activating p53 functions possibly through Bcl-2/Bax imbalance and caspase-9 and -3 regulation. Icariin treatment also induced DNA damage in HCT116 cells.