Design of Novel and Selective Inhibitors of Urokinase-type Plasminogen Activator with Improved Pharmacokinetic Properties for Use as Antimetastatic Agents

• Published in: The Journal of biological chemistry Vol. 279; no. 32; pp. 33613 - 33622
• Main Authors: Schweinitz, Andrea, Steinmetzer, Torsten, Banke, Ingo J., Arlt, Matthias J.E., Stürzebecher, Anne, Schuster, Oliver, Geissler, Andreas, Giersiefen, Helmut, Zeslawska, Ewa, Jacob, Uwe, Krüger, Achim, Stürzebecher, Jörg
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 06-08-2004; American Society for Biochemistry and Molecular Biology
• Subjects: Amides - chemistry; Animals; Benzamidines - chemistry; Binding Sites; Crystallization; Crystallography, X-Ray; Drug Design; Enzyme Inhibitors - chemistry; Enzyme Inhibitors - pharmacokinetics; Enzyme Inhibitors - therapeutic use; Female; Fibrosarcoma; Humans; Kinetics; Lung Neoplasms - prevention & control; Lung Neoplasms - secondary; Mice; Mice, Nude; Models, Molecular; Molecular Structure; Neoplasm Metastasis - prevention & control; Neoplasm Transplantation; Rats; Rats, Wistar; Structure-Activity Relationship; Tumor Cells, Cultured; Urokinase-Type Plasminogen Activator - antagonists & inhibitors; Urokinase-Type Plasminogen Activator - chemistry; Urokinase-Type Plasminogen Activator - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M314151200

The serine protease urokinase-type plasminogen activator (uPA) interacts with a specific receptor (uPAR) on the surface of various cell types, including tumor cells, and plays a crucial role in pericellular proteolysis. High levels of uPA and uPAR often correlate with poor prognosis of cancer patients. Therefore, the specific inhibition of uPA with small molecule active-site inhibitors is one strategy to decrease the invasive and metastatic activity of tumor cells. We have developed a series of highly potent and selective uPA inhibitors with a C-terminal 4-amidinobenzylamide residue. Optimization was directed toward reducing the fast elimination from circulation that was observed with initial analogues. The x-ray structures of three inhibitor/uPA complexes have been solved and were used to improve the inhibition efficacy. One of the most potent and selective derivatives, benzylsulfonyl-d-Ser-Ser-4-amidinobenzylamide (inhibitor 26), inhibits uPA with a Ki of 20 nm. This inhibitor was used in a fibrosarcoma model in nude mice using lacZ-tagged human HT1080 cells, to prevent experimental lung metastasis formation. Compared with control (100%), an inhibitor dose of 2 × 1.5 mg/kg/day reduced the number of experimental metastases to 4.6 ± 1%. Under these conditions inhibitor 26 also significantly prolonged survival. All mice from the control group died within 43 days after tumor cell inoculation, whereas 50% of mice from the inhibitor-treated group survived more than 117 days. This study demonstrates that the specific inhibition of uPA by these inhibitors may be a useful strategy for the treatment of cancer to prevent metastasis.