Selective urokinase-type plasminogen activator inhibitors. 4. 1-(7-sulfonamidoisoquinolinyl)guanidines.

1-isoquinolinylguanidines were previously disclosed as potent and selective inhibitors of urokinase-type plasminogen activator (uPA). Further investigation of this template has revealed that incorporation of a 7-sulfonamide group furnishes a new series of potent and highly selective uPA inhibitors. Potency and selectivity can be achieved with sulfonamides derived from a variety of amines and is further enhanced by the incorporation of sulfonamides derived from amino acids. The binding mode of these 1-isoquinolinylguanidines has been investigated by X-ray cocrystallization studies. uPA inhibitor 26 was selected for further evaluation based on its excellent enzyme potency (Ki 10 nM) and selectivity profile (4000-fold versus tPA and 2700-fold versus plasmin). In vitro, compound 26 is able to inhibit exogenous uPA in human chronic wound fluid (IC50=0.89 microM). In vivo, in a porcine acute excisional wound model, following topical delivery, compound 26 is able to penetrate into pig wounds and inhibit exogenous uPA activity with no adverse effect on wound healing parameters. On the basis of this profile, compound 26 (UK-371,804) was selected as a candidate for further preclinical evaluation for the treatment of chronic dermal ulcers.

Structure-based design and synthesis of novel non-zinc chelating MMP-12 inhibitors.

A new class of MMP-12 inhibitors was discovered and optimized using structure-based drug design methods. Modeling studies using a known MMP-12 crystal structure identified a new interaction mode for these new MMP-12 inhibitors. Further optimization resulted in the discovery of a compound displaying nanomolar activity against MMP-12 and which was co-crystallized with MMP-12.

Crystal structures of novel non-peptidic, non-zinc chelating inhibitors bound to MMP-12.

Human macrophage elastase (MMP-12) plays an important role in inflammatory processes and has been implicated in diseases such as emphysema and chronic obstructive pulmonary disease (COPD). It is therefore an attractive target for therapeutic agents. As part of a structure-based drug design programme to find new inhibitors of MMP-12, the crystal structures of the MMP-12 catalytic domain (residues 106-268) complexed to three different non-peptidic small molecule inhibitors have been determined. The structures reveal that all three ligands bind in the S1' pocket but show varying degrees of interaction with the Zn atom. The structures of the complexes with inhibitors CP-271485 and PF-00356231 reveal that their central morpholinone and thiophene rings, respectively, sit over the Zn atom at a distance of approximately 5A, locating the inhibitors halfway down the S1' pocket. In both of these structures, an acetohydroxamate anion, an artefact of the crystallisation solution, chelates the zinc atom. By contrast, the acetohydroxamate anion is displaced by the ligand in the structure of MMP-12 complexed to PD-0359601 (Bayer), a potent zinc chelating N-substituted biaryl butyric acid, used as a reference compound for crystallisation. Although a racemate was used for the crystallisation, the S enantiomer only is bound in the crystal. Important hydrophobic interactions between the inhibitors and residues from the S1' pocket are observed in all of the structures. The relative selectivity displayed by these ligands for MMP-12 over other MMP family members is discussed.