title: Suppression of Ku80 correlates with radiosensitivity and telomere shortening in the U2OS telomerase-negative osteosarcoma cell line.
abstract: Ku70/80 heterodimer is a central element in the nonhomologous end joining (NHEJ) DNA repair pathway, Ku80 playing a key role in regulating the multiple functions of Ku proteins. It has been found that the Ku80 protein located at telomeres is a major contributor to radiosensitivity in some telomerase positive human cancer cells. However, in ALT human osteosarcoma cells, the precise function in radiosensitivity and telomere maintenance is still unknown. The aim of this study was to investigate the effects of Ku80 depletion in the U2OS ALT cell line cell line. Suppression of Ku80 expression was performed using a vector-based shRNA and stable Ku80 knockdown in cells was verified by Western blotting. U2OS cells treated with shRNA-Ku80 showed lower radiobiological parameters (D0, Dq and SF2) in clonogenic assays. Furthermore, shRNA-Ku80 vector transfected cells displayed shortening of the telomere length and showed less expression of TRF2 protein. These results demonstrated that down-regulation of Ku80 can sensitize ALT cells U2OS to radiation, and this radiosensitization is related to telomere length shortening.
authors.affiliation: Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University, Wuhan, China. fxzhouwhu@gmail.com
authors.forename: Liu
authors.initials: L
authors.lastname: Hu
authors.forename: Qin-Qin
authors.initials: QQ
authors.lastname: Wu
authors.forename: Wen-Bo
authors.initials: WB
authors.lastname: Wang
authors.forename: Huan-Gang
authors.initials: HG
authors.lastname: Jiang
authors.forename: Lei
authors.initials: L
authors.lastname: Yang
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: Hai-Jun
authors.initials: HJ
authors.lastname: Yu
authors.forename: Cong-Hua
authors.initials: CH
authors.lastname: Xie
authors.forename: Yun-Feng
authors.initials: YF
authors.lastname: Zhou
authors.forename: Fu-Xiang
authors.initials: FX
authors.lastname: Zhou
mesh_terms: D034961:Antigens, Nuclear / Q000096:biosynthesis* / Q000235:genetics; D045744:Cell Line, Tumor; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D015536:Down-Regulation; D006801:Humans; D000072200:Ku Autoantigen; D012516:Osteosarcoma / Q000235:genetics* / Q000532:radiotherapy*; D034622:RNA Interference; D034741:RNA, Small Interfering; D011836:Radiation Tolerance / Q000235:genetics*; D019098:Telomerase / Q000172:deficiency / Q000235:genetics; D016615:Telomere / Q000378:metabolism; D059505:Telomere Homeostasis / Q000235:genetics; D059506:Telomere Shortening / Q000235:genetics*; D035341:Telomeric Repeat Binding Protein 2 / Q000096:biosynthesis / Q000235:genetics
chemical_list: D034961:Antigens, Nuclear; D004268:DNA-Binding Proteins; D034741:RNA, Small Interfering; C504753:TERF2 protein, human; D035341:Telomeric Repeat Binding Protein 2; D019098:Telomerase; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen