title: Downregulation of cell surface CA125/MUC16 induces epithelial-to-mesenchymal transition and restores EGFR signalling in NIH:OVCAR3 ovarian carcinoma cells.
abstract: BACKGROUND
  Epithelial ovarian cancer (EOC) cells are prone to metastasise throughout the peritoneal cavity. The epithelial-to-mesenchymal transition (EMT) is a necessary step towards metastatic tumour progression. CA125/MUC16 mucin is a high-molecular-weight glycoprotein overexpressed in the majority of serous carcinomas, suggesting a possible role in the pathogenesis of these cancers.
  
  
  METHODS
  The role of CA125/MUC16 in EMT was investigated using single-chain antibody-mediated knockdown of cell surface CA125/MUC16 in overexpressing EOC NIH:OVCAR3 cells.
  
  
  RESULTS
  CA125/MUC16 knockdown was associated with morphological alterations along with decreased surface expression of epithelial markers (E-cadherin, cytokeratin-18) and increased expression of mesenchymal markers (N-cadherin, vimentin). Co-immunoprecipitation experiments revealed that CA125/MUC16 binds to E-cadherin and β-catenin complexes. The in vitro studies showed disruption of cell-cell junctions, enhanced motility, migration and invasiveness in CA125/MUC16 knockdown cells. Enhanced epidermal growth factor receptor (EGFR) activation was observed in CA125/MUC16 knockdown cells along with increased Akt and ERK1/2 phosphorylation, which are downstream effectors of EGFR, and increased MMP-2 and MMP-9 expression and activities. Epidermal growth factor receptor inhibition strongly inhibited the motility of CA125/MUC16 knockdown cells.
  
  
  CONCLUSIONS
  Our findings suggest that CA125/MUC16 plays a role in EMT, presumably through its interaction with E-cadherin and β-catenin complexes and by modulating EGFR and its downstream signalling pathway in NIH:OVCAR3 cells.
authors.affiliation: Département de Microbiologie et Infectiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001, 12ième Avenue Nord, Sherbrooke, Quebec, Canada J1H 5N4.
authors.forename: M
authors.initials: M
authors.lastname: Comamala
authors.forename: M
authors.initials: M
authors.lastname: Pinard
authors.forename: C
authors.initials: C
authors.lastname: Thériault
authors.forename: I
authors.initials: I
authors.lastname: Matte
authors.forename: A
authors.initials: A
authors.lastname: Albert
authors.forename: M
authors.initials: M
authors.lastname: Boivin
authors.forename: J
authors.initials: J
authors.lastname: Beaudin
authors.forename: A
authors.initials: A
authors.lastname: Piché
authors.forename: C
authors.initials: C
authors.lastname: Rancourt
mesh_terms: D000954:Antigens, Surface / Q000378:metabolism / Q000502:physiology; D018394:CA-125 Antigen / Q000378:metabolism* / Q000502:physiology; D015820:Cadherins / Q000378:metabolism; D002277:Carcinoma / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D015536:Down-Regulation / Q000502:physiology; D058750:Epithelial-Mesenchymal Transition / Q000502:physiology; D066246:ErbB Receptors / Q000378:metabolism* / Q000502:physiology; D005260:Female; D055785:Gene Knockdown Techniques; D006801:Humans; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D010051:Ovarian Neoplasms / Q000378:metabolism* / Q000473:pathology; D011485:Protein Binding / Q000187:drug effects; D034741:RNA, Small Interfering / Q000494:pharmacology; D051176:beta Catenin / Q000378:metabolism
chemical_list: D000954:Antigens, Surface; D018394:CA-125 Antigen; D015820:Cadherins; C451759:MUC16 protein, human; D008565:Membrane Proteins; D034741:RNA, Small Interfering; D051176:beta Catenin; C512478:EGFR protein, human; D066246:ErbB Receptors