A Primary Investigation On Relationship Between Radiosensitivity And Radiation-induced Apoptosis In Three Tumor Cell Lines

Objective:To observe radiation-induced apoptosis on human small cell lung cancer NCI-H446 cell and human cervical squamous carcinoma Siha cell and human gastric carcinoma SGC-7901 cell.To explore the relationship between radiosensitivity and radiation-induced apoptosis. Apoptosis can be used as potential predictors of radiosensitivity for tumor cells.Methods:Three tumor cell lines NCI-H446, Siha and SGC-7901 were irradiated by 60Coγ-ray, The study four groups were examined: the control group,the group of NCI-H446 alone,the group of Siha alone and the group of SGC-7901 alone.The control group was given no radiation.The radiation absorbed doses were set as followed: 1 Gy,2 Gy,3 Gy,5 Gy,7 Gy,10 Gy. Radiation survival curves were fitted by the statistic software Graphpad Prism ,the parameters of D0 and Dq values from the best fit curves were used to evaluate he radiosensitivity of the three tumor cell lines. DNA Ladder can be detected by Agarose gel electrophoresis. the cell morphologic features of apoptosis were observed by means of Electron microscope assay. Flow cytometry (FCM) Annexinⅴ/PI dual staining was applied to observe the apoptosis changes of NCI-H446, Siha and SGC-7901 cells in different groups, To observe radiation-induced apoptosis on human small cell lung cancer NCI-H446 cell and human cervical squamous carcinoma Siha cell and human gastric carcinoma SGC-7901 cell.Results:The tumor cell with the smallest D0 and Dq was NCI-H446, followed consecutively by Siha and SGC-7901.The most radio-sensitivite 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-H446>Siha>SGC-7901, which was well correlated with their radio-sensitivite.Conclusion:Radiation can induced tumor cell apoptosis, The rate of apoptosis was positively correlated with the radiation dose. Apoptosis is correlated to cell radio-sensitivite, and can be used as potential predictors of radio-sensitivite for tumor cells.