title: SRC3 Phosphorylation at Serine 543 Is a Positive Independent Prognostic Factor in ER-Positive Breast Cancer.
abstract: OBJECTIVE
  The steroid receptor coactivator SRC3 is essential for the transcriptional activity of estrogen receptor α (ERα). SRC3 is sufficient to cause mammary tumorigenesis, and has also been implicated in endocrine resistance. SRC3 is posttranslationally modified by phosphorylation, but these events have not been investigated with regard to functionality or disease association. Here, we investigate the spatial selectivity of SRC3-pS543/DNA binding over the human genome and its expression in primary human breast cancer in relation with outcome.
  
  
  METHODS
  Chromatin immunoprecipitation, coupled with sequencing, was used to determine the chromatin binding patterns of SRC3-pS543 in the breast cancer cell line MCF7 and two untreated primary breast cancers. IHC was used to assess the expression of SRC3 and SRC3-pS543 in 1,650 primary breast cancers. The relationship between the expression of SRC3 and SRC3-pS543, disease-free survival (DFS), and breast cancer specific survival (BCSS) was assessed.
  
  
  RESULTS
  Although total SRC3 is selectively found at enhancer regions, SRC3-pS543 is recruited to promoters of ERα responsive genes, both in the MCF7 cell line and primary breast tumor specimens. SRC3-pS543 was associated with both improved DFS (P = 0.003) and BCSS (P = 0.001) in tamoxifen untreated high-risk patients, such a correlation was not seen in tamoxifen-treated cases, the interaction was statistically significant (P = 0.001). Multivariate analysis showed SRC3-pS543 to be an independent prognostic factor.
  
  
  CONCLUSIONS
  Phosphorylation of SRC3 at S543 affects its genomic interactions on a genome-wide level, where SRC3-pS543 is selectively recruited to promoters of ERα-responsive genes. SRC3-pS543 is a prognostic marker, and a predictive marker of response to endocrine therapy.
authors.affiliation: Department of Molecular Pathology, The Netherlands Cancer Institute, Amsterdam, the Netherlands. c.palmieri@liverpool.ac.uk w.zwart@nki.nl.
authors.forename: Wilbert
authors.initials: W
authors.lastname: Zwart
authors.affiliation: Department of Molecular Pathology, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
authors.forename: Koen D
authors.initials: KD
authors.lastname: Flach
authors.affiliation: Department of Molecular and Clinical Cancer Medicine, Institute of Translational Medicine, The University of Liverpool, Liverpool, United Kingdom.
authors.forename: Bharath
authors.initials: B
authors.lastname: Rudraraju
authors.affiliation: Clinical Oncology Department, Nottingham University City Hospital NHS Trust, Nottingham, United Kingdom.
authors.forename: Tarek M A
authors.initials: TM
authors.lastname: Abdel-Fatah
authors.affiliation: Cancer Research UK Laboratories, Imperial Centre for Translational and Experimental Medicine, Division of Cancer, Imperial College London, London, United Kingdom.
authors.forename: Ondrej
authors.initials: O
authors.lastname: Gojis
authors.affiliation: Department of Molecular Pathology, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
authors.forename: Sander
authors.initials: S
authors.lastname: Canisius
authors.affiliation: Department of Cancer Studies and Molecular Medicine, University of Leicester, Leicester, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Moore
authors.affiliation: Department of Molecular Pathology, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Nevedomskaya
authors.affiliation: Department of Molecular Pathology, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
authors.forename: Mark
authors.initials: M
authors.lastname: Opdam
authors.affiliation: Department of Molecular Pathology, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
authors.forename: Marjolein
authors.initials: M
authors.lastname: Droog
authors.affiliation: Department of Molecular Pathology, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Hofland
authors.affiliation: Cancer Research UK Laboratories, Imperial Centre for Translational and Experimental Medicine, Division of Cancer, Imperial College London, London, United Kingdom.
authors.forename: Steve
authors.initials: S
authors.lastname: Chan
authors.affiliation: Department of Cancer Studies and Molecular Medicine, University of Leicester, Leicester, United Kingdom.
authors.forename: Jacqui
authors.initials: J
authors.lastname: Shaw
authors.affiliation: Division of Pathology, School of Molecular Medical Sciences, University of Nottingham, Nottingham, United Kingdom.
authors.forename: Ian O
authors.initials: IO
authors.lastname: Ellis
authors.affiliation: Clinical Oncology Department, Nottingham University City Hospital NHS Trust, Nottingham, United Kingdom.
authors.forename: R Charles
authors.initials: RC
authors.lastname: Coombes
authors.affiliation: Cancer Research UK Cambridge Institute, Cambridge, United Kingdom.
authors.forename: Jason S
authors.initials: JS
authors.lastname: Carroll
authors.affiliation: Clinical Oncology Department, Nottingham University City Hospital NHS Trust, Nottingham, United Kingdom.
authors.forename: Simak
authors.initials: S
authors.lastname: Ali
authors.affiliation: Department of Molecular and Clinical Cancer Medicine, Institute of Translational Medicine, The University of Liverpool, Liverpool, United Kingdom. Liverpool and Merseyside Academic Breast Unit, The Linda McCartney Centre, Royal Liverpool University Hospital, Liverpool, United Kingdom. Academic Department of Medical Oncology, Clatterbridge Cancer Centre NHS Foundation Trust, Wirral, United Kingdom. c.palmieri@liverpool.ac.uk w.zwart@nki.nl.
authors.forename: Carlo
authors.initials: C
authors.lastname: Palmieri
mesh_terms: D000818:Animals; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D016466:CHO Cells; D045744:Cell Line, Tumor; D002843:Chromatin / Q000378:metabolism; D003412:Cricetulus; D018572:Disease-Free Survival; D047628:Estrogen Receptor alpha / Q000378:metabolism*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000235:genetics; D006801:Humans; D061986:MCF-7 Cells; D056921:Nuclear Receptor Coactivator 3 / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology*; D011379:Prognosis; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics; D012694:Serine / Q000378:metabolism*; D013629:Tamoxifen / Q000494:pharmacology
chemical_list: D018931:Antineoplastic Agents, Hormonal; D014408:Biomarkers, Tumor; D002843:Chromatin; C506487:ESR1 protein, human; D047628:Estrogen Receptor alpha; D013629:Tamoxifen; D012694:Serine; C538866:NCOA3 protein, human; D056921:Nuclear Receptor Coactivator 3