title: Endogenous purification reveals GREB1 as a key estrogen receptor regulatory factor.
abstract: Estrogen receptor-α (ER) is the driving transcription factor in most breast cancers, and its associated proteins can influence drug response, but direct methods for identifying interacting proteins have been limited. We purified endogenous ER using an approach termed RIME (rapid immunoprecipitation mass spectrometry of endogenous proteins) and discovered the interactome under agonist- and antagonist-liganded conditions in breast cancer cells, revealing transcriptional networks in breast cancer. The most estrogen-enriched ER interactor is GREB1, a potential clinical biomarker with no known function. GREB1 is shown to be a chromatin-bound ER coactivator and is essential for ER-mediated transcription, because it stabilizes interactions between ER and additional cofactors. We show a GREB1-ER interaction in three xenograft tumors, and using a directed protein-protein approach, we find GREB1-ER interactions in half of ER(+) primary breast cancers. This finding is supported by histological expression of GREB1, which shows that GREB1 is expressed in half of ER(+) cancers, and predicts good clinical outcome. These findings reveal an unexpected role for GREB1 as an estrogen-specific ER cofactor that is expressed in drug-sensitive contexts.
authors: Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK.
authors: Hisham
authors: H
authors: Mohammed
authors: Clive
authors: C
authors: D'Santos
authors: Aurelien A
authors: AA
authors: Serandour
authors: H Raza
authors: HR
authors: Ali
authors: Gordon D
authors: GD
authors: Brown
authors: Alan
authors: A
authors: Atkins
authors: Oscar M
authors: OM
authors: Rueda
authors: Kelly A
authors: KA
authors: Holmes
authors: Vasiliki
authors: V
authors: Theodorou
authors: Jessica L L
authors: JL
authors: Robinson
authors: Wilbert
authors: W
authors: Zwart
authors: Amel
authors: A
authors: Saadi
authors: Caryn S
authors: CS
authors: Ross-Innes
authors: Suet-Feung
authors: SF
authors: Chin
authors: Suraj
authors: S
authors: Menon
authors: John
authors: J
authors: Stingl
authors: Carlo
authors: C
authors: Palmieri
authors: Carlos
authors: C
authors: Caldas
authors: Jason S
authors: JS
authors: Carroll
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D002843:Chromatin / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D047628:Estrogen Receptor alpha / Q000378:metabolism*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D061986:MCF-7 Cells; D051379:Mice; D016513:Mice, SCID; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D060066:Protein Interaction Maps; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D014158:Transcription, Genetic; D014183:Transplantation, Heterologous
chemical_list: D002843:Chromatin; D047628:Estrogen Receptor alpha; C416830:GREB1 protein, human; D009363:Neoplasm Proteins; D034741:RNA, Small Interfering
references: J Biol Chem. 2006 Jun 16;281(24):16272-8
references: 16608856
references: Cell. 2009 Jun 26;137(7):1259-71
references: 19563758
references: J Biol Chem. 2011 Jan 7;286(1):818-29
references: 21044952
references: Nature. 2012 Jan 04;481(7381):389-93
references: 22217937
references: Nature. 1997 Jun 12;387(6634):733-6
references: 9192902
references: Proc Natl Acad Sci U S A. 2010 Feb 9;107(6):2431-6
references: 20133760
references: Nat Methods. 2006 Dec;3(12):981-3
references: 17072306
references: J Mass Spectrom. 2008 Jun;43(6):699-715
references: 18438963
references: Cell. 2003 Dec 12;115(6):751-63
references: 14675539
references: Prostate. 2006 Jun 1;66(8):886-94
references: 16496412
references: Cell. 2005 Jul 15;122(1):33-43
references: 16009131
references: EMBO J. 2011 May 13;30(13):2569-81
references: 21572391
references: PLoS One. 2012;7(10):e46410
references: 23056300
references: Science. 1997 Aug 15;277(5328):965-8
references: 9252329
references: Cell. 2000 Dec 8;103(6):843-52
references: 11136970
references: Breast Cancer Res Treat. 2010 Jul;122(2):371-80
references: 19842031
references: Nat Rev Cancer. 2002 Feb;2(2):101-12
references: 12635173
references: Genome Res. 2013 Jan;23(1):12-22
references: 23172872
references: Proc Natl Acad Sci U S A. 2012 Feb 21;109(8):2748-53
references: 21536917
references: Cancer Res. 2000 Nov 15;60(22):6367-75
references: 11103799
references: PLoS Genet. 2011 Nov;7(11):e1002368
references: 22125492
references: Cancer Cell. 2004 Sep;6(3):263-74
references: 15380517
references: EMBO J. 2011 Oct 14;30(23):4764-76
references: 22002538
references: Cancer Res. 2010 Jan 15;70(2):685-96
references: 20068169
references: Cell. 2011 May 27;145(5):787-99
references: 21620140
references: EMBO Rep. 2008 Jun;9(6):563-8
references: 18451880
references: J Clin Oncol. 2010 Mar 1;28(7):1161-7
references: 20124184
references: Breast Cancer Res Treat. 2005 Jul;92(2):141-9
references: 15986123
references: EMBO J. 2011 Jun 24;30(15):3019-27
references: 21701558
references: Genes Dev. 2010 Jan 15;24(2):171-82
references: 20080953