title: EZH2 inhibition decreases p38 signaling and suppresses breast cancer motility and metastasis.
abstract: EZH2 is a Polycomb group protein that exerts oncogenic functions in breast cancer, where its overexpression is associated with metastatic disease. While it reportedly acts a transcriptional repressor through trimethylation of histone H3 at lysine 27, EZH2 may exhibit context-dependent activating functions. Despite associations with worse outcome and metastasis in breast cancer, a functional role of EZH2 in breast cancer metastasis in vivo has not been demonstrated. Furthermore, whether EZH2 regulates cancer cell phenotype and motility are unknown. In this study, we discovered that knockdown of EZH2 induces a phenotypic reprogramming from mesenchymal to epithelial, reduces motility, and blocks invasion in breast cancer cell lines. In vivo, EZH2 downregulation in MDA-MB-231 cells decreases spontaneous metastasis to the lungs. We uncover an unexpected role of EZH2 in inducing the p38 mitogen-activated protein kinase signaling pathway, an important regulator of breast cancer invasion and metastasis. In breast cancer cells, EZH2 binds to phosphorylated p38 (p-p38) in association with other core members of the Polycomb repressive complex 2, EED, and SUZ12, and EZH2 overexpression leads to increased levels of p-p38 and of activated, downstream pathway proteins. The effect on p-p38 was confirmed in vivo, where it correlated with decreased spontaneous metastasis. In clinical specimens of matched primary and invasive breast carcinomas, we found that EZH2 expression was upregulated in 100 % of the metastases, and that EZH2 and p-p38 were coexpressed in 63 % of cases, consistent with the functional results. Together our findings reveal a new mechanism by which EZH2 functions in breast cancer, and provide direct evidence that EZH2 inhibition reduces breast cancer metastasis in vivo.
authors.affiliation: Department of Pathology, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Heather M
authors.initials: HM
authors.lastname: Moore
authors.forename: Maria E
authors.initials: ME
authors.lastname: Gonzalez
authors.forename: Kathy A
authors.initials: KA
authors.lastname: Toy
authors.forename: Ashley
authors.initials: A
authors.lastname: Cimino-Mathews
authors.forename: Pedram
authors.initials: P
authors.lastname: Argani
authors.forename: Celina G
authors.initials: CG
authors.lastname: Kleer
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D000071221:Enhancer of Zeste Homolog 2 Protein; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics; D005260:Female; D055785:Gene Knockdown Techniques; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000556:secondary; D051379:Mice; D016513:Mice, SCID; D010766:Phosphorylation; D063151:Polycomb Repressive Complex 2 / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: C498409:EZH2 protein, human; D000071221:Enhancer of Zeste Homolog 2 Protein; D063151:Polycomb Repressive Complex 2; D048051:p38 Mitogen-Activated Protein Kinases
references.citation: Cancer Res. 2007 May 1;67(9):4320-7
references.pmid: 17483345
references.citation: Cancer Res. 2012 Sep 15;72(18):4818-28
references.pmid: 22805309
references.citation: Mol Cell Biol. 2007 Jul;27(14):5105-19
references.pmid: 17502350
references.citation: Cancer Res. 2011 Oct 15;71(20):6338-49
references.pmid: 21862636
references.citation: Biochem Soc Trans. 2012 Feb;40(1):79-84
references.pmid: 22260669
references.citation: Nature. 2002 Oct 10;419(6907):624-9
references.pmid: 12374981
references.citation: Biochem J. 2010 Aug 1;429(3):403-17
references.pmid: 20626350
references.citation: Oncogene. 2006 May 18;25(21):2987-98
references.pmid: 16407830
references.citation: Mod Pathol. 2012 Mar;25(3):378-87
references.pmid: 22056952
references.citation: Cell. 2006 Jun 2;125(5):957-69
references.pmid: 16751104
references.citation: J Mammary Gland Biol Neoplasia. 2011 Jun;16(2):127-46
references.pmid: 21448580
references.citation: Virchows Arch. 2010 Dec;457(6):705-13
references.pmid: 20957493
references.citation: CA Cancer J Clin. 2003 Jan-Feb;53(1):5-26
references.pmid: 12568441
references.citation: Proc Natl Acad Sci U S A. 2003 Sep 30;100(20):11606-11
references.pmid: 14500907
references.citation: Biochim Biophys Acta. 1999 Oct 6;1447(1):1-16
references.pmid: 10500238
references.citation: Semin Cancer Biol. 2012 Jun;22(3):194-207
references.pmid: 22406545
references.citation: J Cell Sci. 2000 Jan;113 Pt 2:227-35
references.pmid: 10633074
references.citation: Clin Cancer Res. 2006 Feb 15;12(4):1168-74
references.pmid: 16489070
references.citation: Cell Stem Cell. 2010 Sep 3;7(3):299-313
references.pmid: 20804967
references.citation: Annu Rev Genet. 2004;38:413-43
references.pmid: 15568982
references.citation: Neoplasia. 2004 Mar-Apr;6(2):179-85
references.pmid: 15140407
references.citation: Front Biosci. 2008 May 01;13:3581-93
references.pmid: 18508457
references.citation: Mol Cell. 2013 Jan 10;49(1):80-93
references.pmid: 23159737
references.citation: Mol Cancer. 2010 Aug 03;9:206
references.pmid: 20682068
references.citation: Breast Cancer Res. 2011;13(6):226
references.pmid: 22078097
references.citation: Oncogene. 2011 Mar 17;30(11):1351-9
references.pmid: 21102517
references.citation: J Clin Oncol. 2006 Jan 10;24(2):268-73
references.pmid: 16330673
references.citation: Clin Cancer Res. 2011 May 1;17(9):2613-8
references.pmid: 21367748
references.citation: Cell Signal. 2006 Aug;18(8):1156-68
references.pmid: 16257181
references.citation: Cell. 2009 Nov 25;139(5):871-90
references.pmid: 19945376
references.citation: Nat Rev Cancer. 2009 Aug;9(8):537-49
references.pmid: 19629069
references.citation: Mol Cancer Ther. 2007 Apr;6(4):1212-22
references.pmid: 17406030
references.citation: Oncogene. 2008 Dec 11;27(58):7274-84
references.pmid: 18806826
references.citation: Cancer Res. 2011 Jun 1;71(11):3980-90
references.pmid: 21502402
references.citation: J Mammary Gland Biol Neoplasia. 2001 Oct;6(4):375-92
references.pmid: 12013528
references.citation: EMBO J. 1997 Jun 2;16(11):3219-32
references.pmid: 9214638
references.citation: Eur J Cell Biol. 2010 Aug;89(8):598-606
references.pmid: 20434230
references.citation: Cancer Res. 2006 Apr 15;66(8):4095-9
references.pmid: 16618729
references.citation: Oncogene. 2004 Jun 17;23(28):4930-7
references.pmid: 15077161
references.citation: Cell. 2005 May 6;121(3):425-36
references.pmid: 15882624
references.citation: Oncogene. 2007 Aug 9;26(36):5267-79
references.pmid: 17334397
references.citation: Oncogene. 2009 Feb 12;28(6):843-53
references.pmid: 19079346
references.citation: Br J Cancer. 2012 Jan 17;106(2):243-7
references.pmid: 22187039
references.citation: PLoS One. 2012;7(1):e30393
references.pmid: 22272343
references.citation: Hum Pathol. 2012 Jul;43(7):1003-11
references.pmid: 22154362