Abstract: Objective To analyze the influence of the NOK oncogene on the G1/S distribution in 293T cells and to elucidate the regulated mechanisms responsible for NOK mediated G1/S phase control. Methods, After transiently transfecting NOK into 293T, 293ET and HeLa cells, we detected the cell cycle distributions by flow cytometric approach. Then, we detected the protein expressions of G1/S check point related genes such as cyclin D, cyclin E1,CDK2 and CDK4 by western blot analysis. Results In the 293T、293ET and HeLa cell which was transfered by NOK, the G1 phase proportions of cells were reduced, but the S phase proportions of cells were increased (p<0.05). Significant up-regulations in the expressions of cyclin D,cyclin E1, p-CDK-2, p-CDK-4, p-Akt and p-Rb were observed with the increased delivery of NOK into 293ET cells. Conclusion NOK can promote cell cycle progression by rapidly passing the G1/S check point, which may involve the activations of both Akt and CDK2/4 signaling pathways.

Key words: NOK, cell cycle, cyclin