Zhou-Guang Hui1, Ye-Xiong Li, Wei-Zhi Yang, Jun-Xin Wu, Zi-Hao Yu. 1. Department of Radiation Oncology, Cancer Hospital (Institute), Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100021, P. R. China.
Abstract
BACKGROUND & OBJECTIVE: To enhance the radiosensitivity of cancer cell is one of the most important way to improve the effect of radiotherapy. This study was designed to investigate the radiosensitization of 7-hydroxystaurosporine(UCN-01) by its abrogation of radiation-induced G2 arrest. METHODS: Flow cytometry was used to observe the effect of irradiation and UCN-01 on cell cycle of human nasopharyngeal carcinoma cells (CNE-1) with mutated p53. The effect on radiosensitivity was determined by clonogenic assay and was quantified by calculating the sensitive enhancement ratio (SER). RESULTS: Irradiation resulted in G2 arrest in a dose-dependent manner. The proportion of cells at G2 phase, comparing to the control group (18.4%), was increased to 43.6%, 77.4% and 86.4% after 12 hours with irradiation of 2, 4 and 6 Gy, respectively. Radiation-induced G2 arrest was abrogated by UCN-01 in a concentration-dependent manner. UCN-01 at the concentrations of 50, 100, 200 and 400 nmol/L decreased the proportion of cells in G2 phase from 63.5% in the control group to 28.5%, 25.0%, 16.1% and 13.7%, respectively. UCN-01 resulted in a radiosensitization in CNE-1 cells. The SERs were 2.60 and 3.09, for 100 nmol/L and 200 nmol/L of UCN-01, respectively. CONCLUSION: Radiosensitization of UCN-01 in CNE-1 cells characterized by mutated p53 is associated with its abrogation of radiation-induced G2 arrest.
BACKGROUND & OBJECTIVE: To enhance the radiosensitivity of cancer cell is one of the most important way to improve the effect of radiotherapy. This study was designed to investigate the radiosensitization of 7-hydroxystaurosporine(UCN-01) by its abrogation of radiation-induced G2 arrest. METHODS: Flow cytometry was used to observe the effect of irradiation and UCN-01 on cell cycle of humannasopharyngeal carcinoma cells (CNE-1) with mutated p53. The effect on radiosensitivity was determined by clonogenic assay and was quantified by calculating the sensitive enhancement ratio (SER). RESULTS: Irradiation resulted in G2 arrest in a dose-dependent manner. The proportion of cells at G2 phase, comparing to the control group (18.4%), was increased to 43.6%, 77.4% and 86.4% after 12 hours with irradiation of 2, 4 and 6 Gy, respectively. Radiation-induced G2 arrest was abrogated by UCN-01 in a concentration-dependent manner. UCN-01 at the concentrations of 50, 100, 200 and 400 nmol/L decreased the proportion of cells in G2 phase from 63.5% in the control group to 28.5%, 25.0%, 16.1% and 13.7%, respectively. UCN-01 resulted in a radiosensitization in CNE-1 cells. The SERs were 2.60 and 3.09, for 100 nmol/L and 200 nmol/L of UCN-01, respectively. CONCLUSION: Radiosensitization of UCN-01 in CNE-1 cells characterized by mutated p53 is associated with its abrogation of radiation-induced G2 arrest.