title: PEGylated DX-1000: pharmacokinetics and antineoplastic activity of a specific plasmin inhibitor.
abstract: Novel inhibitors of the urokinase-mediated plasminogen (plg) activation system are potentially of great clinical benefit as anticancer treatments. Using phage display, we identified DX-1000 a tissue factor pathway inhibitor-derived Kunitz domain protein which is a specific high-affinity inhibitor of plasmin (pln) (K(i) = 99 pM). When tested in vitro, DX-1000 blocks plasmin-mediated pro-matrix metalloproteinase-9 (proMMP-9) activation on cells and dose-dependently inhibits tube formation, while not significantly affecting hemostasis and coagulation. However, this low-molecular weight protein inhibitor ( approximately 7 kDa) exhibits rapid plasma clearance in mice and rabbits, limiting its potential clinical use in chronic diseases. After site-specific PEGylation, DX-1000 retains its activity and exhibits a decreased plasma clearance. This PEGylated derivative is effective in vitro, as well as potent in inhibiting tumor growth of green fluorescent protein (GFP)-labeled MDA-MB-231 cells. 4PEG-DX-1000 treatment causes a significant reduction of urokinase-type plasminogen activator (uPA) and plasminogen expressions, a reduction of tumor proliferation, and vascularization. 4PEG-DX-1000 treatment significantly decreases the level of active mitogen-activated protein kinase (MAPK) in the primary tumors and reduces metastasis incidence. Together, our results demonstrate the potential value of plasmin inhibitors as therapeutic agents for blocking breast cancer growth and metastasis.
authors.affiliation: Dyax S.A. Building 22, Boulevard du Rectorat 27B, Sart-Tilman, B-4000 Liege 1, Belgium. ldevy@dyax.com
authors.forename: Laetitia
authors.initials: L
authors.lastname: Devy
authors.forename: Shafaat A
authors.initials: SA
authors.lastname: Rabbani
authors.forename: Mark
authors.initials: M
authors.lastname: Stochl
authors.forename: Mary
authors.initials: M
authors.lastname: Ruskowski
authors.forename: Ian
authors.initials: I
authors.lastname: Mackie
authors.forename: Laurent
authors.initials: L
authors.lastname: Naa
authors.forename: Mark
authors.initials: M
authors.lastname: Toews
authors.forename: Reinoud
authors.initials: R
authors.lastname: van Gool
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.forename: Art
authors.initials: A
authors.lastname: Ley
authors.forename: Robert C
authors.initials: RC
authors.lastname: Ladner
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Dransfield
authors.forename: Paula
authors.initials: P
authors.lastname: Henderikx
mesh_terms: D000818:Animals; D000933:Antifibrinolytic Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D001777:Blood Coagulation / Q000187:drug effects; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D004792:Enzyme Precursors / Q000037:antagonists & inhibitors; D005260:Female; D006487:Hemostasis / Q000187:drug effects; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects; D020780:Matrix Metalloproteinase 9; D061965:Matrix Metalloproteinase Inhibitors; D051379:Mice; D008807:Mice, Inbred BALB C; D011092:Polyethylene Glycols / Q000494:pharmacology*; D011817:Rabbits; D014568:Urokinase-Type Plasminogen Activator / Q000037:antagonists & inhibitors; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology
chemical_list: D000933:Antifibrinolytic Agents; D000970:Antineoplastic Agents; D004792:Enzyme Precursors; D061965:Matrix Metalloproteinase Inhibitors; D011092:Polyethylene Glycols; D048051:p38 Mitogen-Activated Protein Kinases; D014568:Urokinase-Type Plasminogen Activator; C120487:pro-matrix metalloproteinase 9; D020780:Matrix Metalloproteinase 9