RNF8 promotes epithelial-mesenchymal transition of breast cancer cells

Jingyu Kuang1, Li Li1, Limei Guo2, Yanrong Su3, Yuxuan Wang1, Yongjie Xu1, Xiaozhen Wang4, Shucong Meng1, Liandi Lei5, Luzheng Xu5, Genze Shao1
1Department of Cell Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
2Department of Pathology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
3The Irma H. Russo, MD Breast Cancer Research Laboratory, Fox Chase Cancer Center-Temple University Health System, Philadelphia, USA
4Department of Breast Surgery, The First Hospital of Jilin University, Changchun, China
5Lab of Molecular Imaging, Health Science Analysis Center, Peking University, Beijing, China

Tóm tắt

Epithelial-mesenchymal transition (EMT) is a crucial step for solid tumor progression and plays an important role in cancer invasion and metastasis. RNF8 is an ubiquitin E3 ligase with RING domain, and plays essential roles in DNA damage response and cell cycle regulation. However the role of RNF8 in the pathogenesis of breast cancer is still unclear. The expression of RNF8 was examined in different types of breast cell lines by Western Blotting. EMT associated markers were examined by Immunofluorescence and Western Blotting in MCF-7 when RNF8 was ectopically overexpressed, or in MDA-MB-231 when RNF8 was depleted. Transwell and wound healing assays were performed to assess the effect of RNF8 on cell mobility. The xenograft model was done with nude mice to investigate the role of RNF8 in tumor metastasis in vivo. Breast tissue arrays were used to examine the expression of RNF8 by immunohistochemistry. Kaplan-Meier survival analysis for the relationship between survival time and RNF8 signature in breast cancer was done with an online tool ( http://kmplot.com/analysis/ ). RNF8 is overexpressed in highly metastatic breast cancer cell lines. Overexpression of RNF8 in MCF-7 significantly promoted EMT phenotypes and facilitated cell migration. On the contrary, silencing of RNF8 in MDA-MB-231 induced MET phenotypes and inhibited cell migration. Furthermore, we proved that these metastatic behavior promoting effects of RNF8 in breast cancer was associated with the inactivation of GSK-3β and activation of β-catenin signaling. With nude mice xenograft model, we found that shRNA mediated-downregulation of RNF8 reduced tumor metastasis in vivo. In addition, we found that RNF8 expression was higher in malignant breast cancer than that of the paired normal breast tissues, and was positively correlated with lymph node metastases and poor survival time. RNF8 induces EMT in the breast cancer cells and promotes breast cancer metastasis, suggesting that RNF8 could be used as a potential therapeutic target for the prevention and treatment of breast cancer.

Tài liệu tham khảo

Torre LA, Bray F, Siegel RL, Ferlay J, Lortet-Tieulent J, Jemal A. Global cancer statistics, 2012. CA Cancer J Clin. 2015;65(2):87–108. Youlden DR, Cramb SM, Yip CH, Baade PD. Incidence and mortality of female breast cancer in the Asia-Pacific region. Cancer Biol Med. 2014;11(2):101–15. Wang Y, Shang Y. Epigenetic control of epithelial-to-mesenchymal transition and cancer metastasis. Exp Cell Res. 2013;319(2):160–9. Kalluri R, Weinberg RA. The basics of epithelial-mesenchymal transition. J Clin Invest. 2009;119(6):1420–8. Yang J, Weinberg RA. Epithelial-mesenchymal transition: at the crossroads of development and tumor metastasis. Dev Cell. 2008;14(6):818–29. Thiery JP, Acloque H, Huang RY, Nieto MA. Epithelial-mesenchymal transitions in development and disease. Cell. 2009;139(5):871–90. Polyak K, Weinberg RA. Transitions between epithelial and mesenchymal states: acquisition of malignant and stem cell traits. Nat Rev Cancer. 2009;9(4):265–73. Esteller M. Cancer epigenomics: DNA methylomes and histone-modification maps. Nat Rev Genet. 2007;8(4):286–98. Rodriguez-Paredes M, Esteller M. Cancer epigenetics reaches mainstream oncology. Nat Med. 2011;17(3):330–9. Durocher D, Jackson SP. The FHA domain. FEBS Lett. 2002;513(1):58–66. Huen MS, Grant R, Manke I, Minn K, Yu X, Yaffe MB, Chen J. RNF8 transduces the DNA-damage signal via histone ubiquitylation and checkpoint protein assembly. Cell. 2007;131(5):901–14. Kolas NK, Chapman JR, Nakada S, Ylanko J, Chahwan R, Sweeney FD, Panier S, Mendez M, Wildenhain J, Thomson TM. Orchestration of the DNA-damage response by the RNF8 ubiquitin ligase. Science. 2007;318(5856):1637–40. Mailand N, Bekker-Jensen S, Faustrup H, Melander F, Bartek J, Lukas C, Lukas J. RNF8 ubiquitylates histones at DNA double-strand breaks and promotes assembly of repair proteins. Cell. 2007;131(5):887–900. Thorslund T, Ripplinger A, Hoffmann S, Wild T, Uckelmann M, Villumsen B, Narita T, Sixma TK, Choudhary C, Bekker-Jensen S, et al. Histone H1 couples initiation and amplification of ubiquitin signalling after DNA damage. Nature. 2015;527(7578):389–93. Wang B, Matsuoka S, Ballif BA, Zhang D, Smogorzewska A, Gygi SP, Elledge SJ. Abraxas and RAP80 form a BRCA1 protein complex required for the DNA damage response. Science. 2007;316(5828):1194–8. Sobhian B, Shao G, Lilli DR, Culhane AC, Moreau LA, Xia B, Livingston DM, Greenberg RA. RAP80 targets BRCA1 to specific ubiquitin structures at DNA damage sites. Science. 2007;316(5828):1198–202. Kim H, Chen J, Yu X. Ubiquitin-binding protein RAP80 mediates BRCA1-dependent DNA damage response. Science. 2007;316(5828):1202–5. Liu Z, Wu J, Yu X. CCDC98 targets BRCA1 to DNA damage sites. Nat Struct Mol Biol. 2007;14(8):716–20. Hofmann K. Ubiquitin-binding domains and their role in the DNA damage response. DNA Repair (Amst). 2009;8(4):544–56. Ito K, Adachi S, Iwakami R, Yasuda H, Muto Y, Seki N, Okano Y. N-Terminally extended human ubiquitin-conjugating enzymes (E2s) mediate the ubiquitination of RING-finger proteins, ARA54 and RNF8. Eur J Biochem. 2001;268(9):2725–32. Plans V, Scheper J, Soler M, Loukili N, Okano Y, Thomson TM. The RING finger protein RNF8 recruits UBC13 for lysine 63-based self polyubiquitylation. J Cell Biochem. 2006;97(3):572–82. Feng L, Chen J. The E3 ligase RNF8 regulates KU80 removal and NHEJ repair. Nat Struct Mol Biol. 2012;19(2):201–6. Mallette FA, Mattiroli F, Cui G, Young LC, Hendzel MJ, Mer G, Sixma TK, Richard S. RNF8- and RNF168-dependent degradation of KDM4A/JMJD2A triggers 53BP1 recruitment to DNA damage sites. EMBO J. 2012;31(8):1865–78. Lok GT, Sy SM, Dong SS, Ching YP, Tsao SW, Thomson TM, Huen MS. Differential regulation of RNF8-mediated Lys48- and Lys63-based poly-ubiquitylation. Nucleic Acids Res. 2011;40(1):196–205. Plans V, Guerra-Rebollo M, Thomson TM. Regulation of mitotic exit by the RNF8 ubiquitin ligase. Oncogene. 2008;27(10):1355–65. Lu LY, Wu J, Ye L, Gavrilina GB, Saunders TL, Yu X. RNF8-dependent histone modifications regulate nucleosome removal during spermatogenesis. Dev Cell. 2010;18(3):371–84. Peuscher MH, Jacobs JJ. DNA-damage response and repair activities at uncapped telomeres depend on RNF8. Nat Cell Biol. 2011;13(9):1139–45. Pantel K, Brakenhoff RH. Dissecting the metastatic cascade. Nat Rev Cancer. 2004;4(6):448–56. Cowin P, Rowlands TM, Hatsell SJ. Cadherins and catenins in breast cancer. Curr Opin Cell Biol. 2005;17(5):499–508. Bafico A, Liu G, Goldin L, Harris V, Aaronson SA. An autocrine mechanism for constitutive Wnt pathway activation in human cancer cells. Cancer Cell. 2004;6(5):497–506. Liu C, Li Y, Semenov M, Han C, Baeg GH, Tan Y, Zhang Z, Lin X, He X. Control of beta-catenin phosphorylation/degradation by a dual-kinase mechanism. Cell. 2002;108(6):837–47. Behrens J, Jerchow BA, Wurtele M, Grimm J, Asbrand C, Wirtz R, Kuhl M, Wedlich D, Birchmeier W. Functional interaction of an axin homolog, conductin, with beta-catenin, APC, and GSK3beta. Science. 1998;280(5363):596–9. Valenta T, Hausmann G, Basler K. The many faces and functions of beta-catenin. EMBO J. 2012;31(12):2714–36. Fritsch J, Stephan M, Tchikov V, Winoto-Morbach S, Gubkina S, Kabelitz D, Schutze S. Cell fate decisions regulated by K63 ubiquitination of tumor necrosis factor receptor 1. Mol Cell Biol. 2014;34(17):3214–28. Ho YK, Zhi H, Bowlin T, Dorjbal B, Philip S, Zahoor MA, Shih HM, Semmes OJ, Schaefer B, Glover JN et al. HTLV-1 Tax stimulates ubiquitin E3 ligase, ring finger protein 8, to assemble lysine 63-linked polyubiquitin chains for TAK1 and IKK activation. PLoS Pathog. 2015;11(8):e1005102. Behrens J, von Kries JP, Kuhl M, Bruhn L, Wedlich D, Grosschedl R, Birchmeier W. Functional interaction of beta-catenin with the transcription factor LEF-1. Nature. 1996;382(6592):638–42. Korinek V, Barker N, Morin PJ, van Wichen D, de Weger R, Kinzler KW, Vogelstein B, Clevers H. Constitutive transcriptional activation by a beta-catenin-Tcf complex in APC−/− colon carcinoma. Science. 1997;275(5307):1784–7. Schmalhofer O, Brabletz S, Brabletz T. E-cadherin, beta-catenin, and ZEB1 in malignant progression of cancer. Cancer Metastasis Rev. 2009;28(1–2):151–66. Smeenk G, Wiegant WW, Vrolijk H, Solari AP, Pastink A, van Attikum H. The NuRD chromatin-remodeling complex regulates signaling and repair of DNA damage. J Cell Biol. 2010;190(5):741–9. Yang H, Palmbos PL, Wang L, Kim EH, Ney GM, Liu C, Prasad J, Misek DE, Yu X, Ljungman M et al. ATDC (Ataxia Telangiectasia Group D Complementing) promotes radioresistance through an interaction with the RNF8 ubiquitin ligase. J Biol Chem. 2015;290(45):27146–57.