TAS-116 induces G2/M arrest in HeLa cells. HeLa cells were pretreated with 1 µM TAS-116 for 24 hr, and irradiated with X rays (6 Gy, A) or carbon ions (3 Gy, B). Cells were fixed and stained with propidium iodide solution at indicated times after irradiation, and cell cycle distributions were analyzed by using flow cytometry. TAS-116 or mock treated HeLa cells were collected after X-irradiation (4 Gy) or carbon (2 Gy) irradiation, and proteins were immunoblotted with cdc25c and β actin antibodies (C). β actin served as a loading control.