Objective:We investigated the influence of CDK1 and CDK2 expression inhibited by cotransfection of CDK1 and CDK2 siRNA on cell cycle and apoptosis,explored the exact role of cell cycle master regulator in tumor cell apoptosis process.Methods:The siRNA targeting the CDK1 and CDK2 genes were synthesized and simultaneously cotransfected into Hela cells by lipofectamine 2000.48 or 60 h after the cotransfection,CDK1 and CDK2 protein expressions were examined by Western blot.Cell cycle distribution was analyzed by flow cytometry.Cell apoptosis was detected by the Annexin V/PI method.The changes of the transfected cell morphological under a microscope after Wright-Giemsa Staining were studied.Results:CDK1 and CDK2 protein expression was decreased at 48 or 60 h after cotransfection.The accumulation of the G2/M and S phase population in cell cycle of the cotransfected cells at 48 or 60 h after transfection was enhanced obviously compared with control.The ratio of apoptotic cell of cotransfected cells at 48 or 60 h after transfection was increased significantly compared with control.More binucleate or multinucleate cells among cotransfected cells were observed under the microscope.Conclusion:The decreased expression of CDK1 and CDK2 by cotransfection of CDK1 and CDK2 siRNA not only leads to tumor cell cycle arrest in S phase and G2/M phase,but also induces tumor cell apoptosis. Objective: We investigated the influence of CDK1 and CDK2 expression inhibited by cotransfection of CDK1 and CDK2 siRNA on cell cycle and apoptosis, explored the exact role of cell cycle master regulator in tumor cell apoptosis process. Methods: The siRNA targeting the CDK1 and CDK2 genes were synthesized and simultaneously cotransfected into Hela cells by lipofectamine 2000.48 or 60 h after the cotransfection, CDK1 and CDK2 protein expressions were examined by Western blot. Cell cycle distribution was analyzed by flow cytometry. Cell apoptosis was detected by the Annexin V / PI method. The changes of the transfected cell morphological under a microscope after Wright-Giemsa Staining were studied. Results: CDK1 and CDK2 protein expression was decreased at 48 or 60 h after cotransfection.The accumulation of the G2 / M and S phase population in cell cycle of the cotransfected cells at 48 or 60 h after transfection was enhanced obviously compared with control. The ratio of apoptotic cell of cotransfected cells at 48 or 60 h after transfection was increased significantly compared with control. More binucleate or multinucleate cells among cotransfected cells were observed under the microscope. Confc: The decreased expression of CDK1 and CDK2 by cotransfection of CDK1 and CDK2 siRNA not only leads to tumor cell cycle arrest in S phase and G2 / M phase, but also induces tumor cell apoptosis.