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Journal of Cancer Research and Clinical Oncology

, Volume 141, Issue 9, pp 1545–1552 | Cite as

Knockdown of telomeric repeat binding factor 2 enhances tumor radiosensitivity regardless of telomerase status

  • Xiaoxi Yang
  • Zheng Li
  • Lei Yang
  • Han Lei
  • Haijun Yu
  • Zhengkai Liao
  • Fuxiang Zhou
  • Conghua Xie
  • Yunfeng Zhou
Original Article – Cancer Research

Abstract

Purpose

To investigate the effects of TRF2 depletion on radiosensitivity in both the telomerase-positive cell lines (A549) and alternative lengthening of telomere (ALT) cell lines (U2OS).

Methods

X-ray irradiation was used to establish two radioresistant cancer models (A549R and U2OSR) from A549 and U2OS. Colony formation assay was applied to examine the radiosensitivity of radioresistant A549R and U2OSR cells and TRF2 low-expression cells. Real-time PCR and TeloTAGGG Telomerase PCR ELISA Kit were performed to examine telomere length and telomerase activity separately. γ-H2AX was detected by immunofluorescence to assess the radiation-induced DSBs.

Results

Radioresistant cancer models were established, in which TRF2 was significantly over-expressed. Low expression of TRF2 protein could enhance the radiosensitivity and induce telomere length of A549 and U2OS cell shortening. In A549 cells with TRF2 down-regulated, the telomerase activity was inhibited, too. TRF2 deficiency increases γ-H2AX foci and fails to protect telomere from radiation.

Conclusion

The data suggest that TRF2 is a radioresistant protein in A549 and U2OS cells, and could potentially be a target for radiosensitization of both telomerase-positive and ALT cells in radiotherapy.

Keywords

TRF2 Radioresistant Telomere DNA damage response 

Notes

Acknowledgments

This research was supported by the National Natural Science Foundation of China (No. 81071825, 81201755), the Doctoral Fund of Ministry of Education of China (No. 20120141130010) and the Fundamental Research Funds for the Central Universities. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Conflict of interest

The authors declare that they have no conflict of interest.

References

  1. Ayouaz A, Raynaud C, Heride C, Revaud D, Sabatier L (2008) Telomeres: hallmarks of radiosensitivity. Biochimie 90:60–72CrossRefPubMedGoogle Scholar
  2. Bombarde O, Boby C, Gomez D et al (2010) TRF2/RAP1 and DNA–PK mediate a double protection against joining at telomeric ends. EMBO J 29:1573–1584PubMedCentralCrossRefPubMedGoogle Scholar
  3. Cabuy E, Newton C, Joksic G et al (2005) Accelerated telomere shortening and telomere abnormalities in radiosensitive cell lines. Radiat Res 164:53–62CrossRefPubMedGoogle Scholar
  4. Denchi EL, de Lange T (2007) Protection of telomeres through independent control of ATM and ATR by TRF2 and POT1. Nature 448:1068–1071CrossRefPubMedGoogle Scholar
  5. Gomez-Millan J, Goldblatt EM, Gryaznov SM, Mendonca MS, Herbert BS (2007) Specific telomere dysfunction induced by GRN163L increases radiation sensitivity in breast cancer cells. Int J Radiat Oncol Biol Phys 67:897–905CrossRefPubMedGoogle Scholar
  6. Huda N, Abe S, Gu L, Mendonca MS, Mohanty S, Gilley D (2012) Recruitment of TRF2 to laser-induced DNA damage sites. Free Radic Biol Med 53:1192–1197CrossRefPubMedGoogle Scholar
  7. Ji XM, Xie CH, Fang MH, Zhou FX, Zhang WJ, Zhang MS, Zhou YF (2006) Efficient inhibition of human telomerase activity by antisense oligonucleotides sensitizes cancer cells to radiotherapy. Acta Pharmacol Sin 27:1185–1191CrossRefPubMedGoogle Scholar
  8. Kaul Z, Cesare AJ, Huschtscha LI, Neumann AA, Reddel RR (2011) Five dysfunctional telomeres predict onset of senescence in human cells. EMBO Rep 13:52–59PubMedCentralCrossRefPubMedGoogle Scholar
  9. Li Z, Yang XX, Xia NX, Yang L, Yu HJ, Zhou FX, Xie CH, Zhou YF (2014) PTOP and TRF1 help enhance the radio resistance in breast cancer cell. Cancer Cell Int 14:7PubMedCentralCrossRefPubMedGoogle Scholar
  10. Ma H, Zhou Z, Wei S et al (2011) Shortened telomere length is associated with increased risk of cancer a meta-analysis. PLoS One 6:e20466PubMedCentralCrossRefPubMedGoogle Scholar
  11. McIlrath J, Bouffler SD, Samper E et al (2001) Telomere length abnormalities in mammalian radiosensitive cells. Cancer Res 61:912–915PubMedGoogle Scholar
  12. Mistuhashi N, Takahashi T, Sakurai H et al (1996) A radioresistant variant cell line isolated from a radiosensitive rat yolk sac tumor cell line: different of early radiation-induced morphological changes, especially apoptosis. Int J Radiat Biol 69:329–336CrossRefGoogle Scholar
  13. Nakamura M, Masutomi K, Kyo S, Hashimoto M, Maida Y, Kanaya T, Tanaka M, Hahn WC, Inoue M (2005) Efficient inhibition of human telomerase reverse transcriptase expression by RNA interference sensitizes cancer cells to ionizing radiation and chemotherapy. Hum Gene Ther 16:859–868CrossRefPubMedGoogle Scholar
  14. Okamoto K, Bartocci C, Ouzounov I, Diedrich JK, Yates JR, Denchi EL (2013) A two-step mechanism for TRF2-mediated chromosome-end protection. Nature 494:502–505PubMedCentralCrossRefPubMedGoogle Scholar
  15. Palm W, de Lange T (2008) How shelterin protects mammalian telomeres. Annu Rev Genet 42:301–334CrossRefPubMedGoogle Scholar
  16. Shi DG, Shi GM, Huang G (2006) Chemosensitivity of irradiated resistant cells of multicellular spheroids in A549 lung adenocarcinoma. Chin J Radiol Med Prot 28:155–158Google Scholar
  17. Slijepcevic P (2004) Is there a link between telomere maintenance and radiosensitivity? Radiat Res 161:82–86CrossRefPubMedGoogle Scholar
  18. Takai H, Smogorzewska A, de Lange T (2003) DNA damage foci at dysfunctional telomeres. Curr Biol 13:1549–1556CrossRefPubMedGoogle Scholar
  19. Yang L, Wang W, Hu L, Yang X, Zhong J, Li Z, Yang H, Lei H, Yu H, Liao Z, Zhou F, Xie C, Zhou Y (2013) Telomere-binding protein TPP1 modulates telomere homeostasis and confers radioresistance to human colorectal cancer cells. PLoS One 8:e81034PubMedCentralCrossRefPubMedGoogle Scholar
  20. Zhong YH, Liao ZK, Zhou FX, Xie CH, Xiao CY, Pan DF, Luo ZG, Liu SQ, Zhou YF (2008) Telomere length inversely correlates with radiosensitivity in human carcinoma cells with the same tissue background. Biochem Biophys Res Commun 367:84–89CrossRefPubMedGoogle Scholar
  21. Zhou FX, Liao ZK, Dai J, Xiong J, Xie CH, Luo ZG, Liu SQ, Zhou YF (2007) Radiosensitization effect of zidovudine on human malignant glioma cells. Biochem. Biophys. Res Commun 354:351–356CrossRefPubMedGoogle Scholar
  22. Zongaro S, Verri A, Giulotto E, Mondello C (2008) Telomere length and radiosensitivity in human fibroblast clones immortalized by ectopic telomerase expression. Oncol Rep 19:1605–1609PubMedGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Xiaoxi Yang
    • 1
  • Zheng Li
    • 1
  • Lei Yang
    • 1
  • Han Lei
    • 1
  • Haijun Yu
    • 1
  • Zhengkai Liao
    • 1
  • Fuxiang Zhou
    • 1
  • Conghua Xie
    • 1
  • Yunfeng Zhou
    • 1
  1. 1.Department of Radiation and Medical Oncology, Zhongnan HospitalWuhan UniversityWuhanChina

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