title: p130Cas/Cyclooxygenase-2 axis in the control of mesenchymal plasticity of breast cancer cells.
abstract: BACKGROUND
  Intrinsic plasticity of breast carcinoma cells allows them to undergo a transient and reversible conversion into mesenchymal cells to disseminate into distant organs, where they can re-differentiate to an epithelial-like status to form a cohesive secondary mass. The p130Cas scaffold protein is overexpressed in human ER+ and HER2+ breast cancer where it contributes to cancer progression, invasion and resistance to therapy. However, its role in regulating mesenchymal aggressive breast cancer cells remains to be determined. The aim of this study was to investigate the molecular and functional involvement of this adaptor protein in breast cancer cell plasticity.
  
  
  METHODS
  We used silencing strategies and rescue experiments to evaluate phenotypic and biochemical changes from mesenchymal to epithelial traits in breast tumor cell lines. In the mouse A17 cell model previously related to mesenchymal cancer stem cells and basal-like breast cancer, we biochemically dissected the signaling pathways involved and performed functional in vivo tumor growth ability assays. The significance of the signaling platform was assessed in a human setting through the use of specific inhibitors in aggressive MDA-MB-231 subpopulation LM2-4175 cells. To evaluate the clinical relevance of the results, we analyzed publicly available microarray data from the Netherlands Cancer Institute and from the Koo Foundation Sun Yat-Sen Cancer Center.
  
  
  RESULTS
  We show that p130Cas silencing induces loss of mesenchymal features, by downregulating Vimentin, Snail, Slug and Twist transcriptional factors, resulting in the acquirement of epithelial-like traits. Mechanistically, p130Cas controls Cyclooxygenase-2 transcriptional expression, which in turn contributes to p130Cas-dependent maintenance of mesenchymal phenotype. This cascade of events also compromises in vivo tumor growth through inhibition of cell signaling controlling cell cycle progression. c-Src and JNK kinases are sequential players in p130Cas/ Cyclooxygenase-2 axis and their pharmacological inhibition is sufficient to downregulate Cyclooxygenase-2 leading to an epithelial phenotype. Finally, in silico microarray data analysis indicates that p130Cas and Cyclooxygenase-2 concomitant overexpression predicts poor survival and high probability of breast tumor recurrence.
  
  
  CONCLUSIONS
  Overall, these data identify a new p130Cas/Cyclooxygenase-2 axis as a crucial element in the control of breast tumor plasticity, opening new therapeutic strategies leading to inhibition of these pathways in aggressive breast carcinoma.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Bisaro
authors.forename: Maura
authors.initials: M
authors.lastname: Montani
authors.forename: Georgia
authors.initials: G
authors.lastname: Konstantinidou
authors.forename: Cristina
authors.initials: C
authors.lastname: Marchini
authors.forename: Lucia
authors.initials: L
authors.lastname: Pietrella
authors.forename: Manuela
authors.initials: M
authors.lastname: Iezzi
authors.forename: Mirco
authors.initials: M
authors.lastname: Galiè
authors.forename: Francesca
authors.initials: F
authors.lastname: Orso
authors.forename: Annalisa
authors.initials: A
authors.lastname: Camporeale
authors.forename: Shana M
authors.initials: SM
authors.lastname: Colombo
authors.forename: Paola
authors.initials: P
authors.lastname: Di Stefano
authors.forename: Giusy
authors.initials: G
authors.lastname: Tornillo
authors.forename: Maria P
authors.initials: MP
authors.lastname: Camacho-Leal
authors.forename: Emilia
authors.initials: E
authors.lastname: Turco
authors.forename: Daniela
authors.initials: D
authors.lastname: Taverna
authors.forename: Sara
authors.initials: S
authors.lastname: Cabodi
authors.forename: Augusto
authors.initials: A
authors.lastname: Amici
authors.forename: Paola
authors.initials: P
authors.lastname: Defilippi
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D000081247:CSK Tyrosine-Protein Kinase; D045744:Cell Line, Tumor; D050719:Crk-Associated Substrate Protein / Q000235:genetics / Q000378:metabolism*; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D051379:Mice; D008954:Models, Biological; D010641:Phenotype; D019655:Quantitative Trait, Heritable; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D050719:Crk-Associated Substrate Protein; D051546:Cyclooxygenase 2; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; C000631346:CSK protein, human; D048031:JNK Mitogen-Activated Protein Kinases