title: ERbeta1 represses basal breast cancer epithelial to mesenchymal transition by destabilizing EGFR.
abstract: BACKGROUND
  Epithelial to mesenchymal transition (EMT) is associated with the basal-like breast cancer phenotypes. 60% of basal-like cancers have been shown to express wild-type estrogen receptor beta (ERbeta1). However, it is still unclear whether the ERbeta expression is related to EMT, invasion and metastasis in breast cancer. In the present study, we examined whether ERbeta1 through regulating EMT can influence invasion and metastasis in basal-like cancers.
  
  
  METHODS
  Basal-like breast cancer cells (MDA-MB-231 and Hs578T) in which ERbeta1 was either overexpressed or downregulated were analyzed for their ability to migrate and invade (wound-healing assay, matrigel-coated Transwell assay) as well as for the expression of EMT markers and components of the EGFR pathway (immunoblotting, RT-PCR). Coimmunoprecipitation and ubiquitylation assays were employed to examine whether ERbeta1 alters EGFR protein degradation and the interaction between EGFR and the ubiquitin ligase c-Cbl. The metastatic potential of the ERbeta1-expressing MDA-MB-231 cells was evaluated in vivo in a zebrafish xenotransplantation model and the correlation between ERbeta1 and E-cadherin expression was examined in 208 clinical breast cancer specimens by immunohistochemistry.
  
  
  RESULTS
  Here we show that ERbeta1 inhibits EMT and invasion in basal-like breast cancer cells when they grow either in vitro or in vivo in zebrafish. The inhibition of EMT correlates with an ERbeta1-mediated upregulation of miR-200a/b/429 and the subsequent repression of ZEB1 and SIP1, which results in increased expression of E-cadherin. The positive correlation of ERbeta1 and E-cadherin expression was additionally observed in breast tumor samples. Downregulation of the basal marker EGFR through stabilization of the ubiquitin ligase c-Cbl complexes and subsequent ubiquitylation and degradation of the activated receptor is involved in the ERbeta1-mediated repression of EMT and induction of EGFR signaling abolished the ability of ERbeta1 to sustain the epithelial phenotype.
  
  
  CONCLUSIONS
  Taken together, the results of our study strengthen the association of ERbeta1 with the regulation of EMT and propose the receptor as a potential crucial marker in predicting metastasis in breast cancer.
authors.forename: Christoforos
authors.initials: C
authors.lastname: Thomas
authors.forename: Gayani
authors.initials: G
authors.lastname: Rajapaksa
authors.forename: Fotis
authors.initials: F
authors.lastname: Nikolos
authors.forename: Ruixin
authors.initials: R
authors.lastname: Hao
authors.forename: Anne
authors.initials: A
authors.lastname: Katchy
authors.forename: Catherine W
authors.initials: CW
authors.lastname: McCollum
authors.forename: Maria
authors.initials: M
authors.lastname: Bondesson
authors.forename: Phil
authors.initials: P
authors.lastname: Quinlan
authors.forename: Alastair
authors.initials: A
authors.lastname: Thompson
authors.forename: Savitri
authors.initials: S
authors.lastname: Krishnamurthy
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Esteva
authors.forename: Jan-Åke
authors.initials: JÅ
authors.lastname: Gustafsson
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D001943:Breast Neoplasms / Q000473:pathology*; D015820:Cadherins / Q000096:biosynthesis; D045744:Cell Line, Tumor; D058750:Epithelial-Mesenchymal Transition; D066246:ErbB Receptors / Q000378:metabolism*; D047629:Estrogen Receptor beta / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D018398:Homeodomain Proteins / Q000096:biosynthesis; D006801:Humans; D061986:MCF-7 Cells; D035683:MicroRNAs / Q000096:biosynthesis; D009361:Neoplasm Invasiveness / Q000473:pathology; D009362:Neoplasm Metastasis / Q000473:pathology; D009368:Neoplasm Transplantation; D018295:Neoplasms, Basal Cell; D009419:Nerve Tissue Proteins / Q000096:biosynthesis; D050721:Proto-Oncogene Proteins c-cbl / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins / Q000096:biosynthesis; D012097:Repressor Proteins / Q000096:biosynthesis; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000096:biosynthesis / Q000378:metabolism; D014183:Transplantation, Heterologous; D054875:Ubiquitination; D015027:Zebrafish; D000074165:Zinc Finger E-box Binding Homeobox 2; D000071799:Zinc Finger E-box-Binding Homeobox 1
chemical_list: D014408:Biomarkers, Tumor; D015820:Cadherins; D047629:Estrogen Receptor beta; C108381:GEMIN2 protein, human; D018398:Homeodomain Proteins; C533896:MIRN200 microRNA, human; C546363:MIRN429 microRNA, human; D035683:MicroRNAs; D009419:Nerve Tissue Proteins; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; C486307:ZEB1 protein, human; C492363:ZEB2 protein, human; D000074165:Zinc Finger E-box Binding Homeobox 2; D000071799:Zinc Finger E-box-Binding Homeobox 1; C479998:estrogen receptor beta isoform M, human; D050721:Proto-Oncogene Proteins c-cbl; C512478:EGFR protein, human; D066246:ErbB Receptors; C067419:CBL protein, human