title: Plasma fibronectin promotes lung metastasis by contributions to fibrin clots and tumor cell invasion.
abstract: The attachment of circulating tumor cells to the blood vessels of distant organs is an important step in metastasis. We show here that experimental lung metastasis by two cell lines, B16F1 melanoma and 3LL lung carcinoma, is greatly reduced in transgenic mice that lack plasma fibronectin. This multifunctional adhesive glycoprotein becomes cross-linked to fibrin during clotting. Here, we report that eliminating plasma fibronectin from the blood circulation reverses the prometastatic effects of blood clotting and tumor cell integrin alphavbeta3. In vitro studies showed that fibrin-fibronectin complexes, but not purified fibrin, supported tumor cell attachment and invasion. These functions correlate with the ability of fibrin-fibronectin complexes to induce the activation of integrin alphavbeta3. Our findings reveal an important contribution of plasma fibronectin in lung metastasis. Furthermore, they suggest that the previously noted effects of blood clotting on lung metastasis might be mediated in part by a fibronectin-alphavbeta3 integrin axis, in which plasma fibronectin has to be incorporated into the blood clot.
authors.affiliation: Departments of Urology and Pathology, University of Pittsburgh School of Medicine, Shadyside Medical Center, Prostate Cancer Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15232, USA.
authors.forename: Gunjan
authors.initials: G
authors.lastname: Malik
authors.forename: Lynn M
authors.initials: LM
authors.lastname: Knowles
authors.forename: Rajiv
authors.initials: R
authors.lastname: Dhir
authors.forename: Shuping
authors.initials: S
authors.lastname: Xu
authors.forename: Shuting
authors.initials: S
authors.lastname: Yang
authors.forename: Erkki
authors.initials: E
authors.lastname: Ruoslahti
authors.forename: Jan
authors.initials: J
authors.lastname: Pilch
mesh_terms: D000818:Animals; D001777:Blood Coagulation / Q000502:physiology; D018827:Carcinoma, Lewis Lung / Q000097:blood* / Q000473:pathology / Q000556:secondary*; D002448:Cell Adhesion / Q000502:physiology; D005337:Fibrin / Q000378:metabolism; D005353:Fibronectins / Q000097:blood*; D039302:Integrin alphaVbeta3 / Q000097:blood; D008175:Lung Neoplasms / Q000097:blood* / Q000556:secondary*; D008546:Melanoma, Experimental / Q000097:blood* / Q000473:pathology / Q000556:secondary*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009361:Neoplasm Invasiveness
chemical_list: D005353:Fibronectins; D039302:Integrin alphaVbeta3; D005337:Fibrin