Transducer of ErbB2.1 enhances radiosensitivity of human lung cancer A549 cells

Objective To evaluate the effect of transducer of ErbB2.1 (TOB1) on radiosensitivity of human lung cancer cell line A549 and investigate the related mechanisms.Methods The lipofectamine mediated TOB1 recombinant plasmid transfection and selective G418 cell culture were performed to obtain lung cancer cell line A549 with over-expressed TOB1.The effects on lung cancer cell radiosensitivity in vitro were evaluated by clonogenic survival analysis,and comet DNA damage assay was used to understand the molecular mechanisms of radiosensitization of TOB1 and investigate its effects on the initial DNA damage response to irradiation.Western blotting analysis was performed to determine the related mechanisms.Results Using Lipofectamine and G418-mediated plasmid stable transfection,multiple clones stably transfected with TOB1 were selected.As compared with parental and mock transfected cells,enhanced radiosensitivity was detected in A549/TOB1 cells and the sensitizing enhancement ratio was 1.63.Comet DNA damage assay revealed that the tail moment of A549/TOB1 cells were (25.71 ± 4.32) ％,which was significantly higher than that of A549 cells.Western blotting analysis revealed that TOB1 could down-regulate the expression of ATM,MGMT,DNA-PKcs,Ku70,Ku80 and XRCC4 as compared with parental cells.Conclusion Overexpression of TOB1 enhanced the radiosensitivity of A549 cells in vitro,at least by its potential function as an expression regulator of DNA damage repair related proteins,as well as its regulation on DNA damage repair. Key words: Transducer of ErbB-2.1 ;  Lung cancer;  Radiosensitivity