Colon cancer is the second most common cause of cancer-related death, indicating that some of its cancer cells are not eradicated by current therapies. The previous studies demonstrated that p66(Shc) protein, a member of Shc family, is highly expressed in colon cancer cells, but the role of p66(Shc) in the progress of colon cancer still unknown. In this study, we found that p66(Shc) highly expressed in colon cancer tissue and colon cancer cell line SW620 cells, HCT8 cells, HCT116 cells and CaCO2 cells. The silence of p66(Shc) in HCT8 cells reduced the proliferation and accelerated the apoptosis, in addition, the expression of pro-apoptotic proteins caspase-3, caspase-9, Bax was enhanced and the expression of anti-apoptotic protein Bcl-2 was declined. Moreover, the cell cycle arrest in G0/G1 phase after HCT8 cells treated with p66(Shc) siRNA. Furthermore, after HCT8 cells treated with p66(Shc) siRNA, the phosphorylation of PI3K and AKT was significantly suppressed, and the expression of Mdm-2, a downstream of AKT, was obviously prohibited, while the expression of p53 was enhanced. These results indicate that the silence of p66(Shc) in HCT8 cells inhibits the viability via PI3K/AKT/Mdm-2/p53 signaling pathway, it may provide a promising approach to prevent the progress of colon cancer cell.
Keywords: Colon cancer; HCT8 cells; PI3K/AKT/Mdm-2; apoptosis; p53; p66Shc.