A Primary Investigation on Relationship between Radiosensitivity and Radiation-induced Apoptosis in Three Tumor Cell Lines

Objective To explore the relationship between the radio-sensitivity and the radiation-induced apoptosis.Methods Three tumor cell lines NCI-H446,Siha and SGC-7901 were irradiated by 60Co γ-rays.The radiobiological characteristics of the three lines were analyzed by the colony-forming assay.Doand Dq were used to compare the radio-sensitivity of the three tumor cell lines.Agarose gel electrophoresis and flow cytometry were used to evaluate apoptosis,and cell morphologic features of apoptosis were observed by means of Electron microscope assay.Apoptosis index was detected by flow cytometry.The relationship between the radio-sensitivity and the radiation-induced apoptosis was then analyzed of the three tumor cell lines.Results The tumor cell with the smallest Do and Dq was NCI-H446,followed consecutively by Siha and SGC-7901.The most radio-sensitive tumor cell was NCI-H446,followed by Siha and SGC-7901.Specific DNA Ladder could be seen by agarose gel electrophoresis.Cell morphologic features of apoptosis,such as the cells contraction,nuclear fragments and nuclear body formation were well demonstrated in electron microscope.The rate of apoptosis was positively correlated with the radiation dose.Apoptosis peak could be detected by FCM,and the apoptosis peak of the three tumor cell lines,from large to small,was NCI-H446SihaSGC-7901,which was well correlated with their radio-sensitivity.Conclusion Radiation can induce tumor cell apoptosis.The rate of apoptosis is positively related to the radiation dose.Apoptosis is correlated to cell radio-sensitivity,and can be used as a potential predictor of radio-sensitivity of tumor cells.