title: Activation of pro-uPA is critical for initial escape from the primary tumor and hematogenous dissemination of human carcinoma cells.
abstract: Urokinase-type plasminogen activator (uPA) and plasmin have long been implicated in cancer progression. However, the precise contributions of the uPA/plasmin system to specific steps involved in cancer cell dissemination have not been fully established. Herein, we have used a highly disseminating variant of the human PC-3 prostate carcinoma cell line, PC-hi/diss, as a prototype of aggressive carcinomas to investigate the mechanisms whereby pro-uPA activation and uPA-generated plasmin functionally contribute to specific stages of metastasis. The PC-hi/diss cells secrete and activate significant amounts of pro-uPA, leading to efficient generation of plasmin in solution and at the cell surface. In a mouse orthotopic xenograft model, treatment with the specific pro-uPA activation-blocking antibody mAb-112 significantly inhibited local invasion and distant metastasis of the PC-hi/diss cells. To mechanistically examine the uPA/plasmin-mediated aspects of tumor cell dissemination, the anti-pro-uPA mAb-112 and the potent serine protease inhibitor, aprotinin, were used in parallel in a number of in vivo assays modeling various rate-limiting steps in early metastatic spread. Our findings demonstrate that, by generating plasmin, activated tumor-derived uPA facilitates early stages of PC-hi/diss dissemination, specifically the escape from the primary tumor and tumor cell intravasation. Moreover, through a series of in vitro and in vivo analyses, we suggest that PC-hi/diss-invasive escape and dissemination may be enhanced by cleavage of stromal fibronectin by uPA-generated plasmin. Together, our findings point to inhibition of pro-uPA activation at the apex of the uPA/plasmin cascade as a therapy-valid approach to control onset of tumor escape and ensuing metastatic spread.
authors.affiliation: Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
authors.forename: Erin M
authors.initials: EM
authors.lastname: Bekes
authors.forename: Elena I
authors.initials: EI
authors.lastname: Deryugina
authors.forename: Tatyana A
authors.initials: TA
authors.lastname: Kupriyanova
authors.forename: Ewa
authors.initials: E
authors.lastname: Zajac
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Botkjaer
authors.forename: Peter A
authors.initials: PA
authors.lastname: Andreasen
authors.forename: James P
authors.initials: JP
authors.lastname: Quigley
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D007611:Aprotinin / Q000494:pharmacology; D045744:Cell Line, Tumor; D002465:Cell Movement; D002642:Chick Embryo; D004789:Enzyme Activation; D005341:Fibrinolysin / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D014183:Transplantation, Heterologous; D019139:Tumor Escape; D014568:Urokinase-Type Plasminogen Activator / Q000276:immunology / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D005353:Fibronectins; D015842:Serine Proteinase Inhibitors; D007611:Aprotinin; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator