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Overexpression of ligase defective E6-associated protein, E6-AP, results in mammary tumorigenesis

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Abstract

E6-associated protein (E6-AP) is a dual function protein. It acts as an E3 ubiquitin-protein ligase enzyme and coactivator of steroid hormone receptors such as estrogen (ERα) and progesterone (PR) receptors. It promotes the degradation of ERα and PR through the ubiquitin–proteasome pathway. Furthermore, it has been shown that the levels of E6-AP are inversely associated with that of ERα in human breast tumors. But the role of wild-type human E6-AP and its ubiquitin-protein ligase activity in mammary tumorigenesis is still unknown. To investigate this role, the authors utilized transgenic mice lines that specifically overexpress either the wild-type human E6-AP (E6-APWT) or the ubiquitin-protein ligase defective E6-AP that contains C833S mutation (E6-APC833S) in the mammary gland. To further substantiate the role of E6-AP in the development of breast tumorigenesis, it was also examined the expression of E6-AP in a large cohort of human breast cancer samples. The transgenic mice that overexpress wild-type E6-AP (E6-APWT) fail to develop mammary tumors. Unlike the E6-APWT mice, the E6-APC833S mice that overexpress ubiquitin-protein ligase defective E6-AP protein develop mammary hyperplasia with a median latency of 18 months. These observations suggest that the inactivation of the ubiquitin-protein ligase function of E6-AP is sufficient to initiate the process of mammary tumor development. Furthermore, the data also suggests that E6-AP exerts its effects on target cells by modulating the protein levels and functions of ERα and PR. In addition, it was found in human breast cancer patients that the level of E6-AP is decreased in invasive breast tumors compared to normal breast tissue. Moreover, the authors also show that the survival patterns for E6-AP negative patients were worse compared to E6-AP positive patients. Taken together, these data suggests that E6-AP may act as a tumor suppressor in breast.

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Abbreviations

E6-AP:

E6 associated protein

ER:

Estrogen receptor

PR:

Progesterone receptor

AR:

Androgen receptor

GR:

Glucocorticoid receptor

Hect:

Homologus to E6-AP carboxy terminus

DCIS:

Ductal carcinoma in situ

IC:

Invasive carcinoma

SRA:

Steroid receptor RNA activator

AIB:

Amplified in brest cancer

H&E:

Hematoxylin and eosin

MMTV:

Mouse mammary tumor virus

TAM:

Tumor-associated macrophage

References

  1. Scheffner M, Huibregtse JM, Vierstra RD, Howley PM (1993) The HPV-16 E6 and E6-AP complex functions as a ubiquitin-protein ligase in the ubiquitination of p53. Cell 75(3):495–505

    Article  PubMed  CAS  Google Scholar 

  2. Nawaz Z, Lonard DM, Smith CL, Lev-Lehman E, Tsai SY, Tsai MJ, O’Malley BW (1999) The Angelman syndrome-associated protein, E6-AP, is a coactivator for the nuclear hormone receptor superfamily. Mol Cell Biol 19(2):1182–1189

    PubMed  CAS  Google Scholar 

  3. Gao X, Mohsin SK, Gatalica Z, Fu G, Sharma P, Nawaz Z (2005) Decreased expression of e6-associated protein in breast and prostate carcinomas. Endocrinology 146(4):1707–1712

    Article  PubMed  CAS  Google Scholar 

  4. Ramamoorthy S, Dhananjayan SC, Demayo FJ, Nawaz Z (2010) Isoform-specific degradation of PR-B by E6-AP is critical for normal mammary gland development. Mol Endocrinol 24 (11):2099–2113. doi:10.1210/me.2010-0116

    Google Scholar 

  5. Khan OY, Fu G, Ismail A, Srinivasan S, Cao X, Tu Y, Lu S, Nawaz Z (2006) Multifunction steroid receptor coactivator, E6-associated protein, is involved in development of the prostate gland. Mol Endocrinol 20(3):544–559

    Article  PubMed  CAS  Google Scholar 

  6. Huibregtse JM, Scheffner M, Howley PM (1993) Localization of the E6-AP regions that direct human papillomavirus E6 binding, association with p53, and ubiquitination of associated proteins. Mol Cell Biol 13(8):4918–4927

    PubMed  CAS  Google Scholar 

  7. Huibregtse JM, Scheffner M, Beaudenon S, Howley PM (1995) A family of proteins structurally and functionally related to the E6-AP ubiquitin-protein ligase. Proc Natl Acad Sci USA 92(7):2563–2567

    Article  PubMed  CAS  Google Scholar 

  8. Huibregtse JM, Scheffner M, Beaudenon S, Howley PM (1995) A family of proteins structurally and functionally related to the E6-AP ubiquitin-protein ligase. Proc Natl Acad Sci USA 92(11):5249

    Article  PubMed  CAS  Google Scholar 

  9. Kumar S, Kao WH, Howley PM (1997) Physical interaction between specific E2 and Hect E3 enzymes determines functional cooperativity. J Biol Chem 272(21):13548–13554

    Article  PubMed  CAS  Google Scholar 

  10. Conzen SD (2008) Minireview: nuclear receptors and breast cancer. Mol Endocrinol 22(10):2215–2228. doi:10.1210/me.2007-0421

    Article  PubMed  CAS  Google Scholar 

  11. Hewitt SC, Harrell JC, Korach KS (2005) Lessons in estrogen biology from knockout and transgenic animals. Annu Rev Physiol 67:285–308. doi:10.1146/annurev.physiol.67.040403.115914

    Article  PubMed  CAS  Google Scholar 

  12. Green S, Walter P, Greene G, Krust A, Goffin C, Jensen E, Scrace G, Waterfield M, Chambon P (1986) Cloning of the human oestrogen receptor cDNA. J Steroid Biochem 24(1):77–83

    Article  PubMed  CAS  Google Scholar 

  13. Jeltsch JM, Krozowski Z, Quirin-Stricker C, Gronemeyer H, Simpson RJ, Garnier JM, Krust A, Jacob F, Chambon P (1986) Cloning of the chicken progesterone receptor. Proc Natl Acad Sci USA 83(15):5424–5428

    Article  PubMed  CAS  Google Scholar 

  14. Murphy LC, Watson P (2002) Steroid receptors in human breast tumorigenesis and breast cancer progression. Biomed Pharmacother 56(2):65–77

    Article  PubMed  CAS  Google Scholar 

  15. Dimri G, Band H, Band V (2005) Mammary epithelial cell transformation: insights from cell culture and mouse models. Breast Cancer Res 7(4):171–179. doi:10.1186/bcr1275

    Article  PubMed  CAS  Google Scholar 

  16. Fisher ER, Osborne CK, McGuire WL, Redmond C, Knight WA 3rd, Fisher B, Bannayan G, Walder A, Gregory EJ, Jacobsen A, Queen DM, Bennett DE, Ford HC (1981) Correlation of primary breast cancer histopathology and estrogen receptor content. Breast Cancer Res Treat 1(1):37–41

    Article  PubMed  CAS  Google Scholar 

  17. Jones LP, Tilli MT, Assefnia S, Torre K, Halama ED, Parrish A, Rosen EM, Furth PA (2008) Activation of estrogen signaling pathways collaborates with loss of Brca1 to promote development of ERalpha-negative and ERalpha-positive mammary preneoplasia and cancer. Oncogene 27(6):794–802. doi:10.1038/sj.onc.1210674

    Article  PubMed  CAS  Google Scholar 

  18. Herschkowitz JI, Simin K, Weigman VJ, Mikaelian I, Usary J, Hu Z, Rasmussen KE, Jones LP, Assefnia S, Chandrasekharan S, Backlund MG, Yin Y, Khramtsov AI, Bastein R, Quackenbush J, Glazer RI, Brown PH, Green JE, Kopelovich L, Furth PA, Palazzo JP, Olopade OI, Bernard PS, Churchill GA, Van Dyke T, Perou CM (2007) Identification of conserved gene expression features between murine mammary carcinoma models and human breast tumors. Genome Biol 8(5):R76. doi:10.1186/gb-2007-8-5-r76

    Article  PubMed  Google Scholar 

  19. Knight WA, Livingston RB, Gregory EJ, McGuire WL (1977) Estrogen receptor as an independent prognostic factor for early recurrence in breast cancer. Cancer Res 37(12):4669–4671

    PubMed  CAS  Google Scholar 

  20. Osborne CK, Fisher E, Redmond C, Knight WA, Yochmowitz MG, McGuire WL (1981) Estrogen receptor, a marker for human breast cancer differentiation and patient prognosis. Adv Exp Med Biol 138:377–385

    PubMed  CAS  Google Scholar 

  21. Kleinberg DL, Wood TL, Furth PA, Lee AV (2009) Growth hormone and insulin-like growth factor-I in the transition from normal mammary development to preneoplastic mammary lesions. Endocr Rev 30(1):51–74. doi:10.1210/er.2008-0022

    Article  PubMed  CAS  Google Scholar 

  22. Soyal S, Ismail PM, Li J, Mulac-Jericevic B, Conneely OM, Lydon JP (2002) Progesterone’s role in mammary gland development and tumorigenesis as disclosed by experimental mouse genetics. Breast Cancer Res 4(5):191–196

    Article  PubMed  CAS  Google Scholar 

  23. Osborne CK, Yochmowitz MG, Knight WA 3rd, McGuire WL (1980) The value of estrogen and progesterone receptors in the treatment of breast cancer. Cancer 46(12 Suppl):2884–2888

    Article  PubMed  CAS  Google Scholar 

  24. Knight WA 3rd, Osborne CK, McGuire WL (1980) Hormone receptors in primary and advanced breast cancer. Clin Endocrinol Metab 9(2):361–368

    Article  PubMed  Google Scholar 

  25. Tilli MT, Frech MS, Steed ME, Hruska KS, Johnson MD, Flaws JA, Furth PA (2003) Introduction of estrogen receptor-alpha into the tTA/TAg conditional mouse model precipitates the development of estrogen-responsive mammary adenocarcinoma. Am J Pathol 163(5):1713–1719

    Article  PubMed  CAS  Google Scholar 

  26. Howard B, Ashworth A (2006) Signalling pathways implicated in early mammary gland morphogenesis and breast cancer. PLoS Genet 2(8):e112. doi:10.1371/journal.pgen.0020112

    Article  PubMed  Google Scholar 

  27. Gao X, Loggie BW, Nawaz Z (2002) The roles of sex steroid receptor coregulators in cancer. Mol Cancer 1:7

    Article  PubMed  Google Scholar 

  28. Sivaraman L, Nawaz Z, Medina D, Conneely OM, O’Malley BW (2000) The dual function steroid receptor coactivator/ubiquitin protein-ligase integrator E6-AP is overexpressed in mouse mammary tumorigenesis. Breast Cancer Res Treat 62(3):185–195

    Article  PubMed  CAS  Google Scholar 

  29. Kerscher O, Felberbaum R, Hochstrasser M (2006) Modification of proteins by ubiquitin and ubiquitin-like proteins. Annu Rev Cell Dev Biol 22:159–180. doi:10.1146/annurev.cellbio.22.010605.093503

    Article  PubMed  CAS  Google Scholar 

  30. Li M, Brooks CL, Wu-Baer F, Chen D, Baer R, Gu W (2003) Mono- versus polyubiquitination: differential control of p53 fate by Mdm2. Science 302(5652):1972–1975

    Article  PubMed  CAS  Google Scholar 

  31. Oda H, Kumar S, Howley PM (1999) Regulation of the Src family tyrosine kinase Blk through E6AP-mediated ubiquitination. Proc Natl Acad Sci USA 96(17):9557–9562

    Article  PubMed  CAS  Google Scholar 

  32. Dornan D, Wertz I, Shimizu H, Arnott D, Frantz GD, Dowd P, O’Rourke K, Koeppen H, Dixit VM (2004) The ubiquitin ligase COP1 is a critical negative regulator of p53. Nature 429(6987):86–92

    Article  PubMed  CAS  Google Scholar 

  33. Cooper B, Schneider S, Bohl J, Jiang Y, Beaudet A, Vande Pol S (2003) Requirement of E6AP and the features of human papillomavirus E6 necessary to support degradation of p53. Virology 306(1):87–99

    Article  PubMed  CAS  Google Scholar 

  34. Lange CA, Shen T, Horwitz KB (2000) Phosphorylation of human progesterone receptors at serine-294 by mitogen-activated protein kinase signals their degradation by the 26S proteasome. Proc Natl Acad Sci USA 97(3):1032–1037

    Article  PubMed  CAS  Google Scholar 

  35. Nawaz Z, Lonard DM, Dennis AP, Smith CL, O’Malley BW (1999) Proteasome-dependent degradation of the human estrogen receptor. Proc Natl Acad Sci USA 96(5):1858–1862

    Article  PubMed  CAS  Google Scholar 

  36. Nawaz Z, O’Malley BW (2004) Urban renewal in the nucleus: is protein turnover by proteasomes absolutely required for nuclear receptor-regulated transcription? Mol Endocrinol 18(3):493–499. doi:10.1210/me.2003-0388

    Article  PubMed  CAS  Google Scholar 

  37. Fang S, Lorick KL, Jensen JP, Weissman AM (2003) RING finger ubiquitin protein ligases: implications for tumorigenesis, metastasis and for molecular targets in cancer. Semin Cancer Biol 13(1):5–14

    Article  PubMed  CAS  Google Scholar 

  38. Ohta T, Fukuda M (2004) Ubiquitin and breast cancer. Oncogene 23(11):2079–2088. doi:10.1038/sj.onc.1207371

    Article  PubMed  CAS  Google Scholar 

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Acknowledgments

The authors would like to acknowledge Sarath Dhananjayan and Sathish Srinivasan for critically reading the manuscript. This research was supported by the Braman Family Breast Cancer Institute, Sylvester Comprehensive Cancer Center-University of Miami and Bankhead Coley (BK-Prespore09BR-02).

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Authors and Affiliations

  1. Department of Biochemistry and Molecular Biology, Braman Family Breast Cancer Institute (M-877)/Sylvester Comprehensive Cancer Center, University of Miami, Miller School of Medicine, BRB Building, Room 723, 1501 N.W. 10th Avenue, Miami, FL, 33136, USA

    Sivapriya Ramamoorthy, Rozina Tufail, Jimmy El Hokayem & Zafar Nawaz

  2. Department of Pathology, Braman Family Breast Cancer Institute/Sylvester Comprehensive Cancer Center, University of Miami, Miller School of Medicine, 1501 N.W. 10th Avenue, Miami, FL, 33136, USA

    Mercy Jorda

  3. Department of Epidemiology and Public Health, Braman Family Breast Cancer Institute/Sylvester Comprehensive Cancer Center, University of Miami, Miller School of Medicine, 1501 N.W. 10th Avenue, Miami, FL, 33136, USA

    Wei Zhao & Zizi Reis

Authors
  1. Sivapriya Ramamoorthy
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  2. Rozina Tufail
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  7. Zafar Nawaz
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Correspondence to Zafar Nawaz.

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Ramamoorthy, S., Tufail, R., Hokayem, J.E. et al. Overexpression of ligase defective E6-associated protein, E6-AP, results in mammary tumorigenesis. Breast Cancer Res Treat 132, 97–108 (2012). https://doi.org/10.1007/s10549-011-1567-2

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  • DOI: https://doi.org/10.1007/s10549-011-1567-2

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