Structure-directed discovery of potent non-peptidic inhibitors of human urokinase that access a novel binding subsite

Vicki L. Nienaber*, Donald Davidson, Rohinton Edalji, Vincent L. Giranda, Vered Klinghofer, Jack Henkin, Peter Magdalinos, Robert Mantei, Sean Merrick, Jean M. Severin, Richard A. Smith, Kent Stewart, Karl Walter, Jieyi Wang, Michael Wendt, Moshe Weitzberg, Xumiao Zhao, Todd Rockway

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    56 Scopus citations


    Background: Human urokinase-type plasminogen activator has been implicated in the regulation and control of basement membrane and interstitial protein degradation. Because of its role in tissue remodeling, urokinase is a central player in the disease progression of cancer, making it an attractive target for design of an anticancer clinical agent. Few urokinase inhibitors have been described, which suggests that discovery of such a compound is in the early stages. Towards integrating structural data into this process, a new human urokinase crystal form amenable to structure- based drug design has been used to discover potent urokinase inhibitors. Results: On the basis of crystallographic data, 2-naphthamidine was chosen as the lead scaffold for structure-directed optimization. This co-crystal structure shows the compound binding at the primary specificity pocket of the trypsin-like protease and at a novel binding subsite that is accessible from the 8-position of 2-napthamidine. This novel subsite was characterized and used to design two compounds with very different 8-substituents that inhibit urokinase with K(i) values of 30-40 nM. Conclusions: Utilization of a novel subsite yielded two potent urokinase inhibitors even though this site has not been widely used in inhibitor optimization with other trypsin-like proteases, such as those reported for thrombin or factor Xa. The extensive binding pockets present at the substrate-binding groove of these other proteins are blocked by unique insertion loops in urokinase, thus necessitating the utilization of additional binding subsites. Successful implementation of this strategy and characterization of the novel site provides a significant step towards the discovery of an anticancer clinical agent.

    Original languageEnglish (US)
    Pages (from-to)553-563
    Number of pages11
    Issue number5
    StatePublished - May 1 2000


    • Drug design
    • Inhibitors
    • Tumor metastasis
    • Urokinase
    • X-ray crystallography

    ASJC Scopus subject areas

    • Structural Biology
    • Molecular Biology

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