Ku80在石英致DNA双链断裂修复的DNA-PK/JNK信号转导通路中的作用
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摘要
石英粉尘(简称石英)是我国最严重的职业危害因素之一,既可致矽肺,也可致癌。石英可诱导细胞周期改变,也可引起DNA双链断裂损伤(DNA double strand breaks, DSBs)。DNA损伤后,在信号分子介导下细胞周期发生阻滞,DNA损伤修复蛋白被激活进行DNA损伤修复。DNA依赖性蛋白激酶(DNA dependent protein kinase, DNA-PK)是DSBs的传感器之一,识别受损伤的DNA,磷酸化组蛋白H2AX,参与DSBs的非同源末端连接。DNA-PK由调节亚单位Ku和催化亚单位(DNA-PK catalytic subunit, DNA-PKcs)组成,Ku是Ku70与Ku80蛋白通过非共价键紧密结合形成的异二聚体结构。
     以往研究表明,DNA-PK作为蛋白激酶可将多种重要的功能蛋白底物,如Akt、JNK、AP-1、p53等磷酸化,激活DNA损伤信号转导通路,促进修复相关因子的转录、引起细胞周期阻滞或诱导细胞凋亡。本课题组前期研究发现,Akt/JNK/AP-1信号通路可调节CyclinD1和CDK4表达,参与石英诱导的细胞周期S期阻滞;DNA-PKcs具有DSBs传感器功能,通过DNA-PKcs/JNK信号通路,促进石英致DSBs的修复。
     然而,Ku在石英致DSBs修复的DNA-PK/JNK信号通路中的作用仍不清楚。其次,DNA-PK与磷脂酰肌醇-3激酶(Phosphatidylinositol 3 kinase, PI3K)有相同的结构域,均与MAPKs及细胞周期有关,两者在石英致DSBs的修复通路中作用的异同仍有待研究。
     针对以上问题,本研究以人胚肺成纤维细胞(human embryo lung fibroblasts, HELF)为实验模型,采用RNAi、显性失活突变体以及化学抑制剂等研究手段,将我室以往的MAPKs通路研究向上溯源至传感器DNA-PK的调节亚单位Ku,向下追踪到DSBs损伤及修复,重点研究Ku80在石英致DSBs修复及细胞周期改变中的作用,以及Ku80与DNA-PK/JNK通路中信号分子的上下游关系。其次,探讨PI3K在石英致DSBs修复中的作用以及对DNA-PK的影响。
     采用Ku80的siRNA及阴性对照质粒稳定转染HELF;中性彗星实验和/或yH2AX识别抗体技术检测石英致DSBs损伤程度;免疫印迹法测定蛋白的表达及其磷酸化水平;免疫荧光技术检测yH2AX焦点在细胞内的定位及其水平;流式细胞术检测细胞周期。结果如下:
     1成功建立了Ku80 siRNA质粒及阴性对照质粒稳定转染HELF的细胞系。
     2抑制Ku80表达,石英诱导的γH2AX水平的升高被抑制,即H2AX磷酸化是Ku80依赖性的;DSBs修复能力降低;石英诱导的Akt、JNK、AP-1 (c-Jun)磷酸化水平增加受抑制。
     3抑制Ku80表达,石英诱导的G1期细胞百分比进一步减少,S期细胞百分比进一步增加;E2F1蛋白表达及pRb-Ser780水平进一步增加;Cyclin D1、CDK4、CyclinE、CDK2、p53、p53(serl5)、p21表达及磷酸化水平增加受抑制。
     4抑制PI3K活性,石英诱导的Ku70、Ku80和γH2AX表达及磷酸化水平升高受抑制,对DNA-PKcs表达无影响;DSBs修复能力降低。根据以上结果,本研究结论如下:
     1 Ku80是DNA-PK发挥DSBs感受器功能的必要组成成分,通过调节DNA-PK/JNK信号通路促进石英致DSBs的修复。
     2 Ku80通过DNA-PK/JNK信号通路正性调控CyclinD1、CDK4、CyclinE、CDK2表达水平;通过DNA-PK/p53信号通路正性调控p21的表达,负性调控E2F1表达及pRb-Ser780磷酸化水平。Ku80抑制石英诱导的G1期细胞比例减少及S期细胞比例增加。
     3 PI3K通过调节Ku70、Ku80的表达,影响DNA-PK全酶的活性,促进石英致DSBs的修复。
     综上所述,石英诱导的细胞周期改变是各信号分子综合调控的结果。Ku80参与石英诱导的细胞周期改变,引起G1/S期阻滞,为DSBs修复赢得时间,并通过调节DNA-PK/Akt/JNK/AP-1信号通路,促进石英致DSBs的修复。本研究探讨了Ku80在石英致DSBs修复的DNA-PK/JNK信号转导通路中的作用,所得结果加深了对石英致病分子机制的理解,为深入研究石英的致病机理提供了线索。
Background and objective:
     Silica is one of the most serious occupational hazards capable of inducing lung fibrosis and lung cancer after chronic exposure. Previous studies showed that silica exposure can induce cell cycle alternations and DNA double-strand breaks (DSBs).
     Our previous studies showed that silica exposure can induce cell cycle alternations, accompanied with the increased percentages of cells in S phase, and the marked activation of serine/threonine kinase protein kinase B (PKB/Akt), activator protein-1 (AP-1) as well as mitogen activated protein kinase (MAPK). Moreover, Akt/ERK, JNK pathway medicates silica-induced activator protein 1 (AP-1) transactivation, the expression of cyclin Dl and cyclin-dependent kinase 4 (CDK4) as well as cell cycle alternations.
     DNA-dependent protein kinase (DNA-PK), composing of a large catalytic subunit, DNA-PKcs, and a regulatory component, the Ku70-Ku80 heterodimer, is a molecular sensor for DNA damage, and is involved in the repair of DSBs by nonhomologous end-joining (NHEJ) pathway, in which Ku70-Ku80 plays a key role.
     It has been reported that DNA-PK phosphorylates a number of proteins, including Akt, JNK, p53, and many transcription factor such as c-Jun, c-Fos, which eventually contribute to damage-induced cell cycle arrest or cell apoptosis. Our previous studies showed that DNA-PKcs involves silica-induced cell cycle arrest and DSBs repair by DNA-PK/Akt/JNK/AP-1 signaling pathway.
     However, Roles of Ku80 in DNA-PK/JNK signaling pathway mediates silica-induced DSBs repair are not clear. Another, DNA-PK comprises same catalytic domain with Phosphatidylinositol 3 kinase (PI3K), which also involves silica-induced cell cycle alternations and activation of MAPK. Whether PI3K involves in repair of DSBs is neither known.
     Based on above studies, our current studies, which take DSBs and the repair as the breakthrough point, further focused on tracing the upstream sensor of our previous MAPKs pathway, the regulatory component (Ku80 mainly) of DNA-PK, and the biological endpoints of DSBs damage repair effect. In this study, RNAi, dominant negative mutants as well as chemical inhibitors, were used to investigate the roles of Ku80 in DNA-PK/JNK pathway mediates silica-induced DSBs repair as well as the potential effect of this pathway on silica-induced cell cycle and cell cycle regulatory proteins alternation in human embryonic lung fibroblast (HELF), and to detect the upstream or downstream relationship of signaling pathway.
     Methods
     Ku80 siRNA expression vectors was transfected into HELF by lipofectamine. Neutral comet assay and/or yH2AX recognition technology were applied to detect silica-induced DNA double strand breaks. According to the neutral comet experimental result, the DNA repair ability (DNA repair compentence, DRC) was calculated. According to the DRC value, the roles of Ku80 in the silica-induced DSBs repair were analyzed. The expression levels and activity of protein in HELF, such as DNA-PKcs, Akt, JNK, c-Jun, p53, p21, Cyclin D1, CDK4, Cyclin E, CDK2, E2F1, pRb were determined by WB. Cell cycle changes were identified by flow cytometry in HELF. The formation of yH2AX foci in HELF were analyzed by immunofluorescence microscopy.
     Result
     1. Stable transfectants, H-NC and H-Ku80 were established successfully.
     2. Both western blot and immunofluorescence assay analysis indicated that siRNA-mediated silencing of Ku80 strikingly downregulated the silica-induced expression of yH2AX in HELF. It indicates that H2AX phosphorylation is through Ku80 dependent pathway, and Ku80 effects the function of DNA-PK which acts as silica-induced DNA double strand breaks damage sensor.
     Silencing of Ku80 in HELF cells resulted in a decreased of silica-induced DNA damage repair competence compared with the negative control cell.
     After the expression of Ku80 was inhibited, the increase of phosphorylation of Akt at Ser473, JNK at Thr183/Tyr185, and c-Jun at ser63, which induced by silica exposure were potently blocked in HELF cells.
     3. When Ku80 expression was inhibited, the number of S phase cells was marked increased, and the overexpression of p21, p53, CyclinD1, CDK4, Cyclin E, CDK2, and the phosphorylation level of p53 at ser15 were potently blocked. however, the overexpression of E2F1 and the phosphorylation level of pRb-Ser780 were further increased.
     4. Blocking activation of PI3K by dominant negative mutant in DN-p85 cell, silica-induced DNA damage repair competence was decreased compared with the negative control cell induced by silica. And expression levels of Ku70 and Ku80, not DNA-PKcs, were also decreased.
     Conclusion
     1. Ku80 regulates the function of DNA-PK as silica-induced DSBs damage sensor and promotes DSBs repair by DNA-PK/Akt/JNK/AP-1 signaling pathway.
     2. Ku80 mediates silica-induced cell cycle change by DNA-PK/JNK and DNA-PK/p53 signaling pathway.
     3. PI3K promotes silica-induced DSBs damage repair by regulated expression levels of Ku70 and Ku80.
     In brief, this research had initially proven the roles of Ku80 in DNA-PK/JNK pathway in silica-induced DSBs repair. These findings will help us to understand the signal transduction mechanisms involved in the pathogenesis effects of silica at DNA damage reponse level.
引文
1. Adverse effects of crystalline silica exposure.American Thoracic Society Committee of the Scientific Assembly on Environmental and Occupational Health. Am J Respir Crit Care Med 1997,155: 8.
    2. Shukla A, Timblin C R, Hubbard A K, et al. Silica-induced activation of c-Jun-NH2-terminal amino kinases, protracted expression of the activator protein-1 proto-oncogene, fra-1, and S-phase alterations are mediated via oxidative stress. Cancer Res,2001,61:1791-5.
    3. 沈福海.范雪云.刘秉慈.石英致MAPK/cyclinDl-CDK4信号转导通路活化.中华劳动卫生职业病杂志,2007,25:5-10.
    4. Shen F, Fan X, Liu B, et al. Downregulation of cyclin D1-CDK4 protein in human embryonic lung fibroblasts (HELF) induced by silica is mediated through the ERK and JNK pathway. Cell Biol Int, 2008,32:1284-92.
    5. Shen F, Fan X, Liu B, et al. Overexpression of cyclin D1-CDK4 in silica-induced transformed cells is due to activation of ERKs, JNKs/AP-1 pathway. Toxicol Lett,2006,160:185-95.
    6. 贾效伟.刘秉慈.史香林.ERK和JNK/AP-1通路参与石英诱导的细胞周期改变.中华劳动卫生职业病杂志,2008,25:3-6.
    7. Shi X L, Dalal N S and Vallyathan V. ESR evidence for the hydroxyl radical formation in aqueous suspension of quartz particles and its possible significance to lipid peroxidation in silicosis. J Toxicol Environ Health,1988,25:237-45.
    8. Vallyathan V, Shi X L, Dalai N S, et al. Generation of free radicals from freshly fractured silica dust. Potential role in acute silica-induced lung injury. Am Rev Respir Dis,1988,138:1213-9.
    9. Shi X, Mao Y, Daniel L N, et al. Silica radical-induced DNA damage and lipid peroxidation. Environ Health Perspect,1994,102 Suppl 10:149-54.
    10. Zhang Z, Shen H M, Zhang Q F, et al. Involvement of oxidative stress in crystalline silica-induced cytotoxicity and genotoxicity in rat alveolar macrophages. Environ Res,2000,82:245-52.
    11. Ding M, Chen F, Shi X, et al. Diseases caused by silica:mechanisms of injury and disease development. Int Immunopharmacol,2002,2:173-82.
    12. Basaran N, Shubair M, Undeger U, et al. Monitoring of DNA damage in foundry and pottery workers exposed to silica by the alkaline comet assay. Am J Ind Med,2003,43:602-10.
    13. Fanizza C, Ursini C L, Paba E, et al. Cytotoxicity and DNA-damage in human lung epithelial cells exposed to respirable alpha-quartz. Toxicol In Vitro,2007,21:586-94.
    14. Jiang J, Huo K, Chen S, et al. Intracellular chromosome breaks on silicon surface. Biomaterials, 2009,30:2661-5.
    15.张凤梅.刘秉慈.刘海峰.DNA-PKcs在石英诱导的DNA双链断裂修复中的作用.中华劳动卫生职业病杂志,2009,27:2-6.
    16. Hefferin M L and Tomkinson A E. Mechanism of DNA double-strand break repair by non-homologous end joining. DNA Repair (Amst),2005,4:639-48.
    17. Zhou B B and Elledge S J. The DNA damage response:putting checkpoints in perspective. Nature, 2000,408:433-9.
    18. Lieber M R, Ma Y, Pannicke U, et al. Mechanism and regulation of human non-homologous DNA end-joining. Nat Rev Mol Cell Biol,2003,4:712-20.
    19. Wyman C and Kanaar R. DNA double-strand break repair:all's well that ends well. Annu Rev Genet,2006,40:363-83.
    20. Stucki M and Jackson S P. gammaH2AX and MDC1:anchoring the DNA-damage-response machinery to broken chromosomes. DNA Repair (Amst),2006,5:534-43.
    21. Goodarzi A A, Yu Y, Riballo E, et al. DNA-PK autophosphorylation facilitates Artemis endonuclease activity. Embo J,2006,25:3880-9.
    22. Feng J, Park J, Cron P, et al. Identification of a PKB/Akt hydrophobic motif Ser-473 kinase as DNA-dependent protein kinase. J Biol Chem,2004,279:41189-96.
    23. Bozulic L, Surucu B, Hynx D, et al. PKBalpha/Aktl acts downstream of DNA-PK in the DNA double-strand break response and promotes survival. Mol Cell,2008,30:203-13.
    24. Potapova O, Haghighi A, Bost F, et al. The Jun kinase/stress-activated protein kinase pathway functions to regulate DNA repair and inhibition of the pathway sensitizes tumor cells to cisplatin. J Biol Chem,1997,272:14041-4.
    25. Fritz G and Kaina B. Late activation of stress kinases (SAPK/JNK) by genotoxins requires the DNA repair proteins DNA-PKcs and CSB. Mol Biol Cell,2006,17:851-61.
    26. Lees-Miller S P, Sakaguchi K, Ullrich S J, et al. Human DNA-activated protein kinase phosphorylates serines 15 and 37 in the amino-terminal transactivation domain of human p53. Mol Cell Biol,1992,12:5041-9.
    27. Woo R A, McLure K G, Lees-Miller S P, et al. DNA-dependent protein kinase acts upstream of p53 in response to DNA damage. Nature,1998,394:700-4.
    28. Wang S, Guo M, Ouyang H, et al. The catalytic subunit of DNA-dependent protein kinase selectively regulates p53-dependent apoptosis but not cell-cycle arrest. Proc Natl Acad Sci U S A,2000, 97:1584-8.
    29. Collis S J, DeWeese T L, Jeggo P A, et al. The life and death of DNA-PK. Oncogene,2005,24: 949-61.
    30. Bannister A J, Gottlieb T M, Kouzarides T, et al. c-Jun is phosphorylated by the DNA-dependent protein kinase in vitro; definition of the minimal kinase recognition motif. Nucleic Acids Res,1993,21: 1289-95.
    31. Burma S and Chen D J. Role of DNA-PK in the cellular response to DNA double-strand breaks. DNA Repair (Amst),2004,3:909-18.
    32. Pastwa E and Blasiak J. Non-homologous DNA end joining. Acta Biochim Pol,2003,50: 891-908.
    33. Smith G C and Jackson S P. The DNA-dependent protein kinase. Genes Dev,1999,13:916-34.
    34. Falck J, Coates J and Jackson S P. Conserved modes of recruitment of ATM, ATR and DNA-PKcs to sites of DNA damage. Nature,2005,434:605-11.
    35. Subramanian L, Moser B A and Nakamura T M. Recombination-based telomere maintenance is dependent on Tell-MRN and Rap 1 and inhibited by telomerase, Tazl, and Ku in fission yeast. Mol Cell Biol,2008,28:1443-55.
    36. Ding M. Shi X, Dong Z, et al. Freshly fractured crystalline silica induces activator protein-1 activation through ERKs and p38 MAPK. J Biol Chem,1999,274:30611-6.
    37. Dalton T P, Li Q, Bittel D, et al. Oxidative stress activates metal-responsive transcription factor-1 binding activity. Occupancy in vivo of metal response elements in the metallothionein-I gene promoter. J Biol Chem,1996,271:26233-41.
    38. Cho Y J, Seo M S, Kim J K, et al. Silica-induced generation of reactive oxygen species in Rat2 fibroblast:role in activation of mitogen-activated protein kinase. Biochem Biophys Res Commun,1999, 262:708-12.
    39. Hresko R C and Mueckler M. mTOR.RICTOR is the Ser473 kinase for Akt/protein kinase B in 3T3-L1 adipocytes. J Biol Chem,2005,280:40406-16.
    40. Sanchez-Perez I, Murguia J R and Perona R. Cisplatin induces a persistent activation of JNK that is related to cell death. Oncogene,1998,16:533-40.
    41. Hayakawa J, Depatie C, Ohmichi M, et al. The activation of c-Jun NH2-terminal kinase (JNK) by DNA-damaging agents serves to promote drug resistance via activating transcription factor 2 (ATF2)-dependent enhanced DNA repair. J Biol Chem,2003,278:20582-92.
    42.周钦.吴兆龙.AP-1在基因转录调控中的研究进展.国外医学分子生物学分册,2001,23:65-67.
    43. Turatti E, da Costa Neves A, de Magalhaes M H, et al. Assessment of c-Jun, c-Fos and cyclin Dl in premalignant and malignant oral lesions. J Oral Sci,2005,47:71-6.
    44. Albanese C, D'Amico M, Reutens A T, et al. Activation of the cyclin D1 gene by the E1A-associated protein p300 through AP-1 inhibits cellular apoptosis. J Biol Chem,1999,274: 34186-95.
    45. Eferl R and Wagner E F. AP-1:a double-edged sword in tumorigenesis. Nat Rev Cancer,2003,3: 859-68.
    46. Liu Y, Lu C, Shen Q, et al. AP-1 blockade in breast cancer cells causes cell cycle arrest by suppressing G1 cyclin expression and reducing cyclin-dependent kinase activity. Oncogene,2004,23: 8238-46.
    47. Milde-Langosch K, Bamberger A M, Methner C, et al. Expression of cell cycle-regulatory proteins rb, pl6/MTS1, p27/KIP1, p21/WAF1, cyclin D1 and cyclin E in breast cancer:correlations with expression of activating protein-1 family members. Int J Cancer,2000,87:468-72.
    48. Levine A J. p53, the cellular gatekeeper for growth and division. Cell,1997,88:323-31.
    49. Haffner R and Oren M. Biochemical properties and biological effects of p53. Curr Opin Genet Dev,1995,5:84-90.
    50. Huang C, Ma W Y, Li J, et al. Essential role of p53 in phenethyl isothiocyanate-induced apoptosis. Cancer Res,1998,58:4102-6.
    51. Wang L, Bowman L, Lu Y, et al. Essential role of p53 in silica-induced apoptosis. Am J Physiol Lung Cell Mol Physiol,2005,288:L488-96.
    52. Yang J, Yu Y, Hamrick H E, et al. ATM, ATR and DNA-PK:initiators of the cellular genotoxic stress responses. Carcinogenesis,2003,24:1571-80.
    53. Dynan W S and Yoo S. Interaction of Ku protein and DNA-dependent protein kinase catalytic subunit with nucleic acids. Nucleic Acids Res,1998,26:1551-9.
    54. Feldmann E, Schmiemann V, Goedecke W, et al. DNA double-strand break repair in cell-free extracts from Ku80-deficient cells:implications for Ku serving as an alignment factor in non-homologous DNA end joining. Nucleic Acids Res,2000,28:2585-96.
    55. Winder D M, Pett M R, Foster N, et al. An increase in DNA double-strand breaks, induced by Ku70 depletion, is associated with human papillomavirus 16 episome loss and de novo viral integration events. J Pathol,2007,213:27-34.
    56. Weterings E, Verkaik N S, Keijzers Q et al. The Ku80 carboxy terminus stimulates joining and artemis-mediated processing of DNA ends. Mol Cell Biol,2009,29:1134-42.
    57. Smart D J, Halicka H D, Schmuck G, et al. Assessment of DNA double-strand breaks and gammaH2AX induced by the topoisomerase Ⅱ poisons etoposide and mitoxantrone. Mutat Res,2008, 641:43-7.
    58.朱志良.庄志雄.黄钰.单细胞凝胶电泳图像分析系统的研制与应用.中华劳动卫生职业病杂志,2001,19:298-300.
    59. Le Hegarat L, Nesslany F, Mourot A, et al. Lack of DNA damage induction by okadaic acid, a marine toxin, in the CHO-Hprt and the in vitro UDS assays. Mutat Res,2004,564:139-47.
    60. Valovicova Z and Gabelova A. Effect of cytosine arabinoside and hydroxyurea on micronucleus formation induced by model clastogens in Chinese hamster V79 cells. Neoplasma,2004,51:442-9.
    61. Valentin-Severin I, Le Hegarat L, Lhuguenot J C, et al. Use of HepG2 cell line for direct or indirect mutagens screening:comparative investigation between comet and micronucleus assays. Mutat Res,2003,536:79-90.
    62. Le Hegarat L, Fessard V, Poul J M, et al. Marine toxin okadaic acid induces aneuploidy in CHO-K1 cells in presence of rat liver postmitochondrial fraction, revealed by cytokinesis-block micronucleus assay coupled to FISH. Environ Toxicol,2004,19:123-8.
    63. Matsuoka A, Sakamoto H, Tadokoro S, et al. The 2-phenylbenzotriazole-type water pollutant PBTA-2 has cytochalasin B-mimetic activity. Mutat Res,2000,464:161-7.
    64. Durocher D and Jackson S P. DNA-PK, ATM and ATR as sensors of DNA damage:variations on a theme? Curr Opin Cell Biol,2001,13:225-31.
    65. Aronsohn A I and Hughes J A. Nuclear localization signal peptides enhance cationic liposome-mediated gene therapy. J Drug Target,1998,5:163-9.
    66. Napoli C, Lemieux C and Jorgensen R. Introduction of a Chimeric Chalcone Synthase Gene into Petunia Results in Reversible Co-Suppression of Homologous Genes in trans. Plant Cell,1990,2: 279-289.
    67. Fire A, Xu S, Montgomery M K, et al. Potent and specific genetic interference by double-stranded RNA in Caenorhabditis elegans. Nature,1998,391:806-11.
    68. Nimura Y, Kawata T, Uzawa K, et al. Silencing Ku80 using small interfering RNA enhanced radiation sensitivity in vitro and in vivo. Int J Oncol,2007,30:1477-84.
    69.庄亮.于世英.黄晓圆.RNAi抑制Ku80表达后促进宫颈癌SiHa细胞的放射敏感性.中国癌症杂志,2007,17:385-389.
    70. Ayene I S, Ford L P and Koch C J. Ku protein targeting by Ku70 small interfering RNA enhances human cancer cell response to topoisomerase Ⅱ inhibitor and gamma radiation. Mol Cancer Ther,2005, 4:529-36.
    71.安静.隋建丽.徐勤枝.siRNA抑制DNA-PKcs表达对Hela细胞增殖的影响.癌变 畸变 突变 2005,17:5.
    72. Chen F, Peterson S R, Story M D, et al. Disruption of DNA-PK in Ku80 mutant xrs-6 and the implications in DNA double-strand break repair. Mutat Res,1996,362:9-19.
    73. Rogakou E P, Pilch D R, Orr A H, et al. DNA double-stranded breaks induce histone H2AX phosphorylation on serine 139. J Biol Chem,1998,273:5858-68.
    74. Wang H, Wang M, Wang H, et al. Complex H2AX phosphorylation patterns by multiple kinases including ATM and DNA-PK in human cells exposed to ionizing radiation and treated with kinase inhibitors. J Cell Physiol,2005,202:492-502.
    75. Rothkamm K and Lobrich M. Evidence for a lack of DNA double-strand break repair in human cells exposed to very low x-ray doses. Proc Natl Acad Sci USA,2003,100:5057-62.
    76. Kuo L J and Yang L X. Gamma-H2AX-a novel biomarker for DNA double-strand breaks. In Vivo,2008,22:305-9.
    77. Mukherjee B, Kessinger C, Kobayashi J, et al. DNA-PK phosphorylates histone H2AX during apoptotic DNA fragmentation in mammalian cells. DNA Repair (Amst),2006,5:575-90.
    78. Daniel R, Ramcharan J, Rogakou E, et al. Histone H2AX is phosphorylated at sites of retroviral DNA integration but is dispensable for postintegration repair. J Biol Chem,2004,279:45810-4.
    79. Kaneko H, Igarashi K, Kataoka K, et al. Heat shock induces phosphorylation of histone H2AX in mammalian cells. Biochem Biophys Res Commun,2005,328:1101-6.
    80. Shimura T, Martin M M, Torres M J, et al. DNA-PK is involved in repairing a transient surge of DNA breaks induced by deceleration of DNA replication. J Mol Biol,2007,367:665-80.
    81. Pan J, She M, Xu Z X, et al. Farnesyltransferase inhibitors induce DNA damage via reactive oxygen species in human cancer cells. Cancer Res,2005,65:3671-81.
    82. Hudson J J, Hsu D W, Guo K, et al. DNA-PKcs-dependent signaling of DNA damage in Dictyostelium discoideum. Curr Biol,2005,15:1880-5.
    83. Stiff T, ODriscoll M, Rief N, et al. ATM and DNA-PK function redundantly to phosphorylate H2AX after exposure to ionizing radiation. Cancer Res,2004,64:2390-6.
    84. Ward I M and Chen J. Histone H2AX is phosphorylated in an ATR-dependent manner in response to replicational stress. J Biol Chem,2001,276:47759-62.
    85. Keogh M C, Kim J A, Downey M, et al. A phosphatase complex that dephosphorylates gammaH2AX regulates DNA damage checkpoint recovery. Nature,2006,439:497-501.
    86. Fairbairn D W, Olive P L and O'Neill K L. The comet assay:a comprehensive review. Mutat Res, 1995,339:37-59.
    87. Omori S, Takiguchi Y, Suda A, et al. Suppression of a DNA double-strand break repair gene, Ku70, increases radio-and chemosensitivity in a human lung carcinoma cell line. DNA Repair (Amst), 2002,1:299-310.
    88. Bertolini L R, Bertolini M, Anderson G B, et al. Transient depletion of Ku70 and Xrcc4 by RNAi as a means to manipulate the non-homologous end-joining pathway. J Biotechnol,2007,128:246-57.
    89. Kotsopoulos J, Chen Z, Vallis K A, et al. DNA repair capacity as a possible biomarker of breast cancer risk in female BRCA1 mutation carriers. Br J Cancer,2007,96:118-25.
    90.农清清.张志勇.何敏.微囊藻毒素-LR对HL60细胞遗传毒作用的研究.中国热带医学,2008,8:898-905.
    91. Watters G P, Smart D J, Harvey J S, et al. H2AX phosphorylation as a genotoxicity endpoint. Mutat Res,2009,679:50-8.
    92. Douglas P, Gupta S, Morrice N, et al. DNA-PK-dependent phosphorylation of Ku70/80 is not required for non-homologous end joining. DNA Repair (Amst),2005,4:1006-18.
    93. Fagin J A. Minireview:branded from the start-distinct oncogenic initiating events may determine tumor fate in the thyroid. Mol Endocrinol,2002,16:903-11.
    94. Kao G D, Jiang Z, Fernandes A M, et al. Inhibition of phosphatidylinositol-3-OH kinase/Akt signaling impairs DNA repair in glioblastoma cells following ionizing radiation. J Biol Chem,2007, 282:21206-12.
    95. Davis R J. Signal transduction by the JNK group of MAP kinases. Cell,2000,103:239-52.
    96. Zou H, Adachi M, Imai K, et al.2-methoxyestradiol, an endogenous mammalian metabolite, radiosensitizes colon carcinoma cells through c-Jun NH2-terminal kinase activation. Clin Cancer Res, 2006,12:6532-9.
    97. Matsuzawa A and Ichijo H. Stress-responsive protein kinases in redox-regulated apoptosis signaling. Antioxid Redox Signal,2005,7:472-81.
    98. Canman C E and Kastan M B. Signal transduction. Three paths to stress relief. Nature,1996,384: 213-4.
    99. Mansouri A, Ridgway L D, Korapati A L, et al. Sustained activation of JNK/p38 MAPK pathways in response to cisplatin leads to Fas ligand induction and cell death in ovarian carcinoma cells. J Biol Chem,2003,278:19245-56.
    100. Brozovic A, Fritz G, Christmann M, et al. Long-term activation of SAPK/JNK, p38 kinase and fas-L expression by cisplatin is attenuated in human carcinoma cells that acquired drug resistance. Int J Cancer,2004,112:974-85.
    101. Gupta R P, Krishnan R A, Kumar S, et al. A rare cause of heart failure-primary hypoparathyroidism. J Assoc Physicians India,2007,55:5224.
    102. Angel P, Szabowski A and Schorpp-Kistner M. Function and regulation of AP-1 subunits in skin physiology and pathology. Oncogene,2001,20:2413-23.
    103. Behrens A, Sibilia M and Wagner E F. Amino-terminal phosphorylation of c-Jun regulates stress-induced apoptosis and cellular proliferation. Nat Genet,1999,21:326-9.
    104. Wang S, Lloyd R V, Hutzler M J, et al. The role of cell cycle regulatory protein, cyclin D1, in the progression of thyroid cancer. Mod Pathol,2000,13:882-7.
    105. Xiong Y, Connolly T, FutcherB, et al. Human D-type cyclin. Cell,1991,65:691-9.
    106. Payton M and Coats S. Cyclin E2, the cycle continues. Int J Biochem Cell Biol,2002,34:315-20.
    107. Ambrosini G, Seelman S L, Qin L X, et al. The cyclin-dependent kinase inhibitor flavopiridol potentiates the effects of topoisomerase I poisons by suppressing Rad51 expression in a p53-dependent manner. Cancer Res,2008,68:2312-20.
    108. Shieh S Y, Taya Y and Prives C. DNA damage-inducible phosphorylation of p53 at N-terminal sites including a novel site, Ser20, requires tetramerization. Embo J,1999,18:1815-23.
    109. Weinberg R A. The retinoblastoma protein and cell cycle control. Cell,1995,81:323-30.
    110. Bartek J, Bartkova J and Lukas J. The retinoblastoma protein pathway in cell cycle control and cancer. Exp Cell Res,1997,237:1-6.
    111. Boehme K A, Kulikov R and Blattner C. p53 stabilization in response to DNA damage requires Akt/PKB and DNA-PK. Proc Natl Acad Sci U S A,2008,105:7785-90.
    112. Lee S H and Kim C H. DNA-dependent protein kinase complex:a multifunctional protein in DNA repair and damage checkpoint. Mol Cells,2002,13:159-66.
    113. Bargonetti J and Manfredi J J. Multiple roles of the tumor suppressor p53. Curr Opin Oncol,2002, 14:86-91.
    114. Harr M W, Graves T G, Crawford E L, et al. Variation in transcriptional regulation of cyclin dependent kinase inhibitor p21waf1/cip1 among human bronchogenic carcinomas. Mol Cancer,2005,4: 23.
    115. Rampakakis E, Di Paola D and Zannis-Hadjopoulos M. Ku is involved in cell growth, DNA replication and Gl-S transition. J Cell Sci,2008,121:590-600.
    116. Mazumder S, Plesca D and Almasan A. A jekyll and hyde role of cyclin E in the genotoxic stress response:switching from cell cycle control to apoptosis regulation. Cell Cycle,2007,6:1437-42.
    117. Mazumder S, Plesca D, Kinter M, et al. Interaction of a cyclin E fragment with Ku70 regulates Bax-mediated apoptosis. Mol Cell Biol,2007,27:3511-20.
    118. Arooz T, Yam C H, Siu W Y, et al. On the concentrations of cyclins and cyclin-dependent kinases in extracts of cultured human cells. Biochemistry,2000,39:9494-501.
    119. Coqueret O. Linking cyclins to transcriptional control. Gene,2002,299:35-55.
    120.舒伟.马清钧.叶昕.CyclinE-CDK2相关蛋白与细胞周期调控.生物技术通信,2008,1:97-100.
    121. Deng M, Li F, Ballif B A, et al. Identification and functional analysis of a novel cyclin e/cdk2 substrate ankrd17. J Biol Chem,2009,284:7875-88.
    122.周芬.吴秋玲.陆羡.组蛋白H2AX的磷酸化及其在肿瘤中的应用.Journal of Oncology,2007,3: 162-165.
    123. Siliciano J D, Canman C E, Taya Y, et al. DNA damage induces phosphorylation of the amino terminus of p53. Genes Dev,1997,11:3471-81.
    124. Burma S, Kurimasa A, Xie G, et al. DNA-dependent protein kinase-independent activation of p53 in response to DNA damage. J Biol Chem,1999,274:17139-43.
    125.余祖滨.白莉.张国强.PI3K/Akt抑制剂对肺癌细胞化疗药物敏感性的影响.重庆医学,2009,38:1340-1342.
    126. Kinner A, Wu W, Staudt C, et al. Gamma-H2AX in recognition and signaling of DNA double-strand breaks in the context of chromatin. Nucleic Acids Res,2008,36:5678-94.
    127. Edstrom A and Ekstrom P A. Role of phosphatidylinositol 3-kinase in neuronal survival and axonal outgrowth of adult mouse dorsal root ganglia explants. J Neurosci Res,2003,74:726-35.
    1. Burma S and Chen D J. Role of DNA-PK in the cellular response to DNA double-strand breaks. DNA Repair (Amst),2004,3:909-18.
    2. Falck J, Coates J and Jackson S P. Conserved modes of recruitment of ATM, ATR and DNA-PKcs to sites of DNA damage. Nature,2005,434:605-11.
    3. Subramanian L, Moser B A and Nakamura T M. Recombination-based telomere maintenance is dependent on Tell-MRN and Rap1 and inhibited by telomerase, Tazl, and Ku in fission yeast. Mol Cell Biol,2008,28:1443-55.
    4. Fanizza C, Ursini C L, Paba E, et al. Cytotoxicity and DNA-damage in human lung epithelial cells exposed to respirable alpha-quartz. Toxicol In Vitro,2007,21:586-94.
    5. Jiang J, Huo K, Chen S, et al. Intracellular chromosome breaks on silicon surface. Biomaterials, 2009,30:2661-5.
    6. 张凤梅.刘秉慈.刘海峰.DNA-PKcs在石英诱导的DNA双链断裂修复中的作用.中华劳动卫生职业病杂志,2009,27:2-6.
    7. Blier P R, Griffith A J, Craft J, et al. Binding of Ku protein to DNA. Measurement of affinity for ends and demonstration of binding to nicks. J Biol Chem,1993,268:7594-601.
    8. Dynan W S and Yoo S. Interaction of Ku protein and DNA-dependent protein kinase catalytic subunit with nucleic acids. Nucleic Acids Res,1998,26:1551-9.
    9. Featherstone C and Jackson S P. Ku, a DNA repair protein with multiple cellular functions? Mutat Res,1999,434:3-15.
    10. Kim C H, Park S J and Lee S H. A targeted inhibition of DNA-dependent protein kinase sensitizes breast cancer cells following ionizing radiation. J Pharmacol Exp Ther,2002,303:753-9.
    11. Nimura Y, Kawata T, Uzawa K, et al. Silencing Ku80 using small interfering RNA enhanced radiation sensitivity in vitro and in vivo. Int J Oncol,2007,30:1477-84.
    12. Boulton S, Kyle S and Durkacz B W. Mechanisms of enhancement of cytotoxicity in etoposide and ionising radiation-treated cells by the protein kinase inhibitor wortmannin. Eur J Cancer,2000,36: 535-41.
    13. Collis S J, DeWeese T L, Jeggo P A, et al. The life and death of DNA-PK. Oncogene,2005,24: 949-61.
    14. Hefferin M L and Tomkinson A E. Mechanism of DNA double-strand break repair by non-homologous end joining. DNA Repair (Amst),2005,4:639-48.
    15. Yang J, Yu Y, Hamrick H E, et al. ATM, ATR and DNA-PK:initiators of the cellular genotoxic stress responses. Carcinogenesis,2003,24:1571-80.
    16. Lombard D B, Chua K F, Mostoslavsky R, et al. DNA repair, genome stability, and aging. Cell, 2005,120:497-512.
    17. Feldmann E, Schmiemann V, Goedecke W, et al. DNA double-strand break repair in cell-free extracts from Ku80-deficient cells:implications for Ku serving as an alignment factor in non-homologous DNA end joining. Nucleic Acids Res,2000,28:2585-96.
    18. Winder D M, Pett M R, Foster N, et al. An increase in DNA double-strand breaks, induced by Ku70 depletion, is associated with human papillomavirus 16 episome loss and de novo viral integration events. J Pathol,2007,213:27-34.
    19. Weterings E, Verkaik N S, Keijzers G, et al. The Ku80 carboxy terminus stimulates joining and artemis-mediated processing of DNA ends. Mol Cell Biol,2009,29:1134-42.
    20. Lisby M and Rothstein R. DNA damage checkpoint and repair centers. Curr Opin Cell Biol,2004, 16:328-34.
    21. Chang I Y, Youn C K, Kim H B, et al. Oncogenic H-Ras up-regulates expression of Ku80 to protect cells from gamma-ray irradiation in NIH3T3 cells. Cancer Res,2005,65:6811-9.
    22. Bertolini L R, Bertolini M, Anderson G B, et al. Transient depletion of Ku70 and Xrcc4 by RNAi as a means to manipulate the non-homologous end-joining pathway. J Biotechnol,2007,128:246-57.
    23. Omori S, Takiguchi Y, Suda A, et al. Suppression of a DNA double-strand break repair gene, Ku70, increases radio-and chemosensitivity in a human lung carcinoma cell line. DNA Repair (Amst), 2002,1:299-310.
    24. Ayene I S, Ford L P and Koch C J. Ku protein targeting by Ku70 small interfering RNA enhances human cancer cell response to topoisomerase Ⅱ inhibitor and gamma radiation. Mol Cancer Ther,2005, 4:529-36.
    25. Lee S H and Kim C H. DNA-dependent protein kinase complex:a multifunctional protein in DNA repair and damage checkpoint. Mol Cells,2002,13:159-66.
    26. Jiang D, Zhou Y, Moxley R A, et al. Purification and identification of positive regulators binding to a novel element in the c-Jun promoter. Biochemistry,2008,47:9318-34.
    27. Convery E, Shin E K, Ding Q, et al. Inhibition of homologous recombination by variants of the catalytic subunit of the DNA-dependent protein kinase (DNA-PKcs). Proc Natl Acad Sci U S A,2005, 102:1345-50.
    28. Takashima Y, Sakuraba M, Koizumi T, et al. Dependence of DNA double strand break repair pathways on cell cycle phase in human lymphoblastoid cells. Environ Mol Mutagen,2009.
    29. Wang S, Lloyd R V, Hutzler M J, et al. The role of cell cycle regulatory protein, cyclin D1, in the progression of thyroid cancer. Mod Pathol,2000,13:882-7.
    30. Rampakakis E, Di Paola D and Zannis-Hadjopoulos M. Ku is involved in cell growth, DNA replication and G1-S transition. J Cell Sci,2008,121:590-600.
    31. Munoz P, Zdzienicka M Z, Blanchard J M, et al. Hypersensitivity of Ku-deficient cells toward the DNA topoisomerase II inhibitor ICRF-193 suggests a novel role for Ku antigen during the G2 and M phases of the cell cycle. Mol Cell Biol,1998,18:5797-808.
    32. Wang S, Guo M, Ouyang H, et al. The catalytic subunit of DNA-dependent protein kinase selectively regulates p53-dependent apoptosis but not cell-cycle arrest. Proc Natl Acad Sci U S A,2000, 97:1584-8.
    33. Gurley K E, Moser R, Gu Y, et al. DNA-PK suppresses a p53-independent apoptotic response to DNA damage. EMBO Rep,2009,10:87-93.
    34. Mazumder S, Plesca D and Almasan A. A jekyll and hyde role of cyclin E in the genotoxic stress response:switching from cell cycle control to apoptosis regulation. Cell Cycle,2007,6:1437-42.
    35. Mazumder S, Plesca D, Kinter M, et al. Interaction of a cyclin E fragment with Ku70 regulates Bax-mediated apoptosis. Mol Cell Biol,2007,27:3511-20.

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