title: Cross-talk between the Tissue Factor/coagulation factor VIIa complex and the tyrosine kinase receptor EphA2 in cancer.
abstract: Tissue Factor (TF) forms a proteolytically active complex together with coagulation factor VIIa (FVIIa) and functions as the trigger of blood coagulation or alternatively activates cell signaling. We recently described that EphA2 of the Eph tyrosine kinase receptor family is cleaved directly by the TF/FVIIa complex. The aim of the present study was to further characterize the cross-talk between TF/FVIIa and EphA2 using in vitro model systems and human cancer specimens.
  
  
  
  Cleavage and phosphorylation of EphA2 was studied by Western blot. Subcellular localization of TF and EphA2 was investigated by a proximity ligation assay and confocal microscopy. Phalloidin staining of the actin cytoskeleton was used to study cell rounding and retraction fiber formation. Expression of TF and EphA2 in human colorectal cancer specimens was examined by immunohistochemistry.
  
  
  
  TF and EphA2 co-localized constitutively in MDA-MB-231 cells, and addition of FVIIa resulted in cleavage of EphA2 by a PAR2-independent mechanism. Overexpression of TF in U251 glioblastoma cells lead to co-localization with EphA2 at the leading edge and FVIIa-dependent cleavage of EphA2. FVIIa potentiated ephrin-A1-induced cell rounding and retraction fiber formation in MDA-MB-231 cells through a RhoA/ROCK-dependent pathway that did not require PAR2-activation. TF and EphA2 were expressed in colorectal cancer specimens, and were significantly correlated.
  
  
  
  These results suggest that TF/FVIIa-EphA2 cross-talk might potentiate ligand-dependent EphA2 signaling in human cancers, and provide initial evidence that it is possible for this interaction to occur in vivo.
authors.affiliation: Department of Medical Sciences, Clinical Chemistry & Science for Life Laboratory, Uppsala University, Uppsala, Sweden. oskar.eriksson@medsci.uu.se.
authors.forename: Oskar
authors.initials: O
authors.lastname: Eriksson
authors.affiliation: Department of Medical Sciences, Clinical Chemistry & Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Åsa
authors.initials: Å
authors.lastname: Thulin
authors.affiliation: Department of Immunology, Genetics & Pathology & Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Asplund
authors.affiliation: Lab Surgpath, The Human Protein Atlas Project, Mumbai Site, Mumbai, India.
authors.forename: Geeta
authors.initials: G
authors.lastname: Hegde
authors.affiliation: Lab Surgpath, The Human Protein Atlas Project, Mumbai Site, Mumbai, India.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Navani
authors.affiliation: Department of Medical Sciences, Clinical Chemistry & Science for Life Laboratory, Uppsala University, Uppsala, Sweden. agneta.siegbahn@medsci.uu.se.
authors.forename: Agneta
authors.initials: A
authors.lastname: Siegbahn
mesh_terms: D015153:Blotting, Western; D015179:Colorectal Neoplasms / Q000378:metabolism*; D015942:Factor VIIa / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D006801:Humans; D007150:Immunohistochemistry; D018613:Microscopy, Confocal; D020239:Receptor Cross-Talk / Q000502:physiology*; D036104:Receptor, EphA2 / Q000378:metabolism*; D013925:Thromboplastin / Q000378:metabolism*; D046888:Tissue Array Analysis
chemical_list: D013925:Thromboplastin; D036104:Receptor, EphA2; D015942:Factor VIIa
keywords: Cell signaling; Coagulation factor; Colorectal cancer; EphA2; Tissue Factor