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http://dx.doi.org/10.7314/APJCP.2013.14.2.795

Suppression of Ku80 Correlates with Radiosensitivity and Telomere Shortening in the U2OS Telomerase-negative Osteosarcoma Cell Line  

Hu, Liu (Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University)
Wu, Qin-Qin (Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University)
Wang, Wen-Bo (Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University)
Jiang, Huan-Gang (Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University)
Yang, Lei (Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University)
Liu, Yu (Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University)
Yu, Hai-Jun (Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University)
Xie, Cong-Hua (Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University)
Zhou, Yun-Feng (Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University)
Zhou, Fu-Xiang (Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University)
Publication Information
Asian Pacific Journal of Cancer Prevention / v.14, no.2, 2013 , pp. 795-799 More about this Journal
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.
Keywords
Ku80; telomerase negative osteosarcoma; U2OS cells; radiosensitivity; telomere length; TRF2;
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1 Bailey SM, Brenneman MA, Halbrook J, et al (2004). The kinase activity of DNA-PK is required to protect mammalian telomeres. DNA Repair, 3, 225-33.   DOI   ScienceOn
2 Bailey SM, Meyne J, Chen DJ, et al (1999). DNA double-strand break repair proteins are required to cap the ends of mammalian chromosomes. Proc Natl Acad Sci USA, 96, 14899-904.   DOI   ScienceOn
3 Barwell J, Pangon L, Georgiou A, et al (2007). Is telomere length in peripheral blood lymphocytes correlated with cancer susceptibility or radiosensitivity? Br J Cancer, 97, 1696-700.   DOI   ScienceOn
4 Bianchi A, de Lange T (1999). Ku binds telomeric DNA in vitro. J Biol Chem, 274, 21223-7.   DOI
5 Boulton SJ, Jackson SP (1998). Components of the Ku-dependent non-homologous end-joining pathway are involved in telomeric length maintenance and telomeric silencing. EMBO J, 17, 1819-28.   DOI   ScienceOn
6 Cawthon RM (2002). Telomere measurement by quantitative PCR. Nucleic Acids Res, 30, e47.   DOI   ScienceOn
7 Chai W, Ford LP, Lenertz L, et al (2002). Human Ku70/80 associates physically with telomerase through interaction with hTERT. J Biol Chem, 277, 47242-7.   DOI   ScienceOn
8 Fink LS, Lerner CA, Torres PF, et al (2010). Ku80 facilitates chromatin binding of the telomere binding protein, TRF2. Cell Cycle, 9, 3798-806.   DOI
9 Gullo C, Au M, Feng G, et al (2006). The biology of Ku and its potential oncogenic role in cancer. Biochim Biophys Acta, 1765, 223-34.
10 Hsu HL, Gilley D, Blackburn EH, et al (1999). Ku is associated with the telomere in mammals. Proc Natl Acad Sci USA, 96, 12454-8.   DOI   ScienceOn
11 Hsu HL, Gilley D, Galande SA, et al (2000). Ku acts in a unique way at the mammalian telomere to prevent end joining. Genes Dev, 14, 2807-12.   DOI
12 Kim H (2008). DNA repair Ku proteins in gastric cancer cells and pancreatic acinar cells. Amino Acids, 34, 195-202.   DOI
13 Lucero H, Gae D, Taccioli GE (2003). Novel localization of the DNA-PK complex in lipid rafts: a putative role in the signal transduction pathway of the ionizing radiation response. J Biol Chem, 278, 22136-43.   DOI   ScienceOn
14 Nimura Y, Kawata T, Uzawa K, et al (2007). Silencing Ku80 using small interfering RNA enhanced radiation sensitivity in vitro and in vivo. Int J Oncol, 30, 1477-84.
15 Polotnianka RM, Li J, Lustig AJ (1998). The yeast Ku heterodimer is essential for protection of the telomere against nucleolytic and recombinational activities. Curr Biol, 8, 831-4.   DOI   ScienceOn
16 Samper E, Goytisolo FA, Slijepcevic P, et al (2000). Mammalian Ku86 protein prevents telomeric fusions independently of the length of TTAGGG repeats and the G-strand overhang. EMBO Rep, 1, 244-52.   DOI   ScienceOn
17 Silver PA, Iglehart JD, Marto JA, et al (2012). DNA ends alter the molecular composition and localization of Ku multicomponent complexes. Mol Cell Proteomics, 11, 411-21.   DOI
18 Yang QS, Gu JL, Du LQ, et al (2008). ShRNA-mediated Ku80 gene silencing inhibits cell proliferation and sensitizes to gamma-radiation and mitomycin C-induced apoptosis in esophageal squamous cell carcinoma lines. J Radiat Res, 49, 399-407.   DOI   ScienceOn
19 Zhong YH, Liao ZK, Zhou FX, et al (2008). Telomere length inversely correlates with radiosensitivity in human carcinoma cells with the same tissue background. Biochem Biophys Res Commun, 367, 84-9.   DOI   ScienceOn
20 Zhou FX, Xiong J, Luo ZG, et al (2010). cDNA expression analysis of a human radiosensitive-radioresistant cell line model identifies telomere function as a hallmark of radioresistance. Radiat Res, 174, 550-7.   DOI   ScienceOn
21 Zongaro S, Verri A, Giulotto E, et al (2008). Telomere length and radiosensitivity in human fibroblast clones immortalized by ectopic telomerase expression. Oncol Rep, 19, 1605-9.