Hydroxamate derivatives of substrate-analogous peptides containing aminomalonic acid are potent inhibitors of matrix metalloproteinases

Novel biodegradable, biomimetic and functionalised polymer scaffolds to prevent expansion of post-infarct left ventricular remodelling

Over the past decade, a large number of strategies and technologies have been developed to reduce heart failure progression. Among these, cardiac tissue engineering is one of the most promising. Aim of this study is to develop a 3D scaffold to treat cardiac failure. A new three-block copolymer, obtained from δ-valerolactone and polyoxyethylene, was synthesised under high vacuum without catalyst. Copolymer/gelatine blends were microfabricated to obtain a ECM-like geometry. Structures were studied under morphological, mechanical, degradation and biological aspects. To prevent left ventricular remodelling, constructs were biofunctionalises with molecularly imprinted nanoparticles towards the matrix metalloproteinase MMP-9. Results showed that materials are able to reproduce the ECM structure with high resolution, mechanical properties were in the order of MPa similar to those of the native myocardium and cell viability was verified. Nanoparticles showed the capability to rebind MMP-9 (specific rebinding 18.67) and to be permanently immobilised on the scaffold surface.

Inhibitors of gelatinase B/matrix metalloproteinase-9 activity

Matrix metalloproteinases form a proteinase family with at least 20 members, which are involved in several pathological conditions and which fulfill a large number of physiological functions. Gelatinase A/MMP-2 is a constitutively produced homeostatic enzyme, whereas gelatinase B/MMP-9 is upregulated in acute and chronic inflammations and forms a target for the development of therapeutic inhibitors. We have used a recently developed assay with fluorescent gelatin to analyze gelatinase inhibitors. A peptidomimetic, based on the consensus sequence of the cleavage sites in type II collagen, and various derivatives of a neutralizing antibody were compared as gelatinase inhibitors. A single-chain variable fragment (scFv) derived from the gelatinase B-selective monoclonal antibody REGA-3G12 was tagged with oligohistidine and was also compared with the untagged scFv. Both scFv derivatives inhibited gelatinase B but the peptidomimetic was inefficient. As an extra control and serendipitously it was found that polyhistidine is an inhibitor of gelatinases, presumably by altering the active site by chelation of the catalytic Zn2+.

Protease inhibitors: Synthesis of L-alanine hydroxamate sulfonylated derivatives as inhibitors of clostridium histolyticum collagenase

L-alanine hydroxamate derivatives were obtained by reaction of alkyl/arylsulfonyl halides with L-alanine, followed by treatment with benzyl chloride, and conversion of the COOH moiety to the CONHOH group with hydroxylamine in the presence of carbodiimides. Other derivatives were obtained by reaction of N-benzyl-alanine with aryl isocyanates, arylsulfonyl isocyanates or benzoyl isothiocyanate, followed by a similar conversion of the COOH to the CONHOH moiety. The obtained compounds were assayed as inhibitors of Clostridium histolyticum collagenase, ChC (EC 3.4.24.3), a zinc enzyme which degrades triple helical collagen. The hydroxamate derivatives were generally 100-500 times more active than the corresponding carboxylates. In the series of synthesized derivatives, substitution patterns leading to the most potent ChC inhibitors were those involving perfluoroalkylsulfonyl- and substituted-arylsulfonyl moieties, such as pentafluorophenylsulfonyl, 3- and 4-protected-aminophenylsulfonyl-, 3- and 4-carboxy-phenylsulfonyl-, 3-trifluoromethyl-phenylsulfonyl-, or 1- and 2-naphthylsulfonyl among others. Similarly to the matrix metalloproteinase (MMP) hydroxamate inhibitors, ChC inhibitors of the type reported here must incorporate hydrophobic moieties at the P(2') and P(3') sites, in order to achieve tight binding to the enzyme.

Rational design of tropoelastin peptide-based inhibitors of metalloproteinases

Abnormal production of matrix metalloproteinases (MMPs) has been observed in a variety of diseases, such as emphysema, atherosclerosis, and cancer metastasis. Destruction of connective tissue ensues and elastin is often a key target. Three of the main elastolytic MMPs are the gelatinases MMP-2 and MMP-9 and the metalloelastase MMP-12. To investigate the possibility of using peptides to inhibit the elastolytic activity of these enzymes, we mapped the sites within tropoelastin recognized by MMP-9 and MMP-12. Peptides that correspond to regions overlapping these sites were then tested for their ability to inhibit these MMPs. These included an unmodified peptide directed against MMP-9 (peptide PP), cysteine-containing peptides that mimicked either the MMP-9 (peptide NCP) or the MMP-12 (peptide lin24) cleavage sites in tropoelastin and their cyclized forms (CP and cyc24, respectively), and a peptide containing a zinc-chelating hydroxamate group directed against MMP-9 (HP). The presence of a free sulfhydryl or hydroxamate group capable of chelating the zinc ion in the active site of the MMPs was generally found to increase the inhibitory activity of the peptides. The specificity of the inhibitors varied, with some of the inhibitors showing activity against all of the MMPs examined. None of the inhibitors had any significant effect on the activity of the unrelated serine protease, plasmin. K(i) values for the inhibitors were in the micromolar range. Our results suggest ways of developing other MMP inhibitors based on substrate recognition sites that may provide greater levels of inhibition.

Oxal hydroxamic acid derivatives with inhibitory activity against matrix metalloproteinases

Several amines, amino acid derivatives and low molecular weight peptides containing an amide-bound oxal hydroxamic acid moiety have been synthesized and tested for their inhibitory effects towards native human gelatinase B (MMP-9) and the catalytic domains of the membrane type MT1-MMP (MMP-14) and of neutrophil collagenase (MMP-8). A number of these compounds exhibited considerable inhibitory activity against the tested metalloproteinases.

Protease inhibitors: synthesis of a series of bacterial collagenase inhibitors of the sulfonyl amino acyl hydroxamate type

A series of sulfonyl amino acyl hydroxamates incorporating alkyl/arylsulfonyl-N-2-nitrobenzyl-L-alanine was prepared. Related compounds were obtained by reaction of N-2-nitrobenzyl-L-Ala with aryl isocyanates, arylsulfonyl isocyanates, or benzoyl isothiocyanate, followed by the conversion of the COOH into the CONHOH moiety. The new compounds were assayed as inhibitors of the Clostridium histolyticum collagenase (ChC), a bacterial protease involved in the degradation of extracellular matrix. Many of the obtained hydroxamates proved to be effective bacterial collagenase inhibitors, the main contributor to activity being the substitution pattern at the sulfonamido moiety. The best ChC inhibitors were those containing pentafluorophenylsulfonyl and 3- and 4-protected-aminophenylsulfonyl P(1)(') groups among others, with affinities in the low nanomolar range. This study also proves that the 2-nitrobenzyl- moiety, similarly to the 4-nitrobenyl one previously investigated (Scozzafava, A.; Supuran, C. T. J. Med. Chem. 2000, 43, 1858-1865) is an efficient P(2)(') anchoring moiety for obtaining potent bacterial collagenase inhibitors.

General synthesis of alpha-substituted 3-bisaryloxy propionic acid derivatives as specific MMP inhibitors

Modulations of alpha and aryl substitutions on 3-aryloxy propionic acid hydroxamates led to novel and potent inhibitors of MMP-2,3,9 and 13, and selectivity versus MMP-1.

Determination of matrix metalloproteinase activity using biotinylated gelatin

Matrix metalloproteinases (MMPs) and, specifically, MMP-2 (gelatinase A) and MMP-9 (gelatinase B) are strongly associated with malignant progression and matrix remodeling. These enzymes are a subject of intensive studies involving screening of comprehensive chemical libraries of synthetic inhibitors. There is no simple method available for measurement of activity of gelatinases and related MMPs. Here, we report a simple, inexpensive, and highly sensitive assay for MMP activity. The assay performed in a 96-well microtiter plate format employs biotin-labeled gelatin (denatured collagen type I) as a substrate. Following the substrate cleavage, only the proteolytic fragments bearing biotin moieties are captured by streptavidin coated on the plastic surface and the captured fragments with at least two biotin molecules should be revealed by streptavidin conjugated with horseradish peroxidase. The frequency of lysine residues is low in collagen type I relative to the MMP cleavage sequences (PXGX). Accordingly, the majority of the cleavage products must be devoid of biotin or possess only one biotin group. Both of these types of fragments cannot be recognized by the horseradish peroxidase-streptavidin conjugate. Therefore, higher gelatinolytic activity is associated with lower signal in the assay. This 2-h assay allows identification of gelatinolytic activity of MMP-2 in concentrations as low as 0.16 ng/ml. The sensitivity of this ELISA-like assay is comparable to that of gelatin zymography, a method widely used to detect gelatinases. However, in contrast to zymography, the assay directly measures the enzymatic activity of MMP samples. The gelatinolytic activity assay permits efficient analyses and screening of the MMP inhibitor panels and allows quantitation of gelatinolytic activity of various MMPs in solution as well as on cell surfaces.

Two crystal structures of human neutrophil collagenase, one complexed with a primed- and the other with an unprimed-side inhibitor: implications for drug design

Two crystal structures of human neutrophil collagenase (HNC, MMP-8), one complexed with a primed- and the other with an unprimed-side inhibitor, were determined using synchrotron radiation at 100 K. Both inhibitors contain non-hydroxamate zinc-binding functions. The Pro-Leu-L-Trp(P)(OH)(2) occupies the unprimed region of the active site, furnishes new structural information regarding interaction between the catalytic zinc ion and the phosphonate group, and is the only example of occupation of the S(1) subsite of MMP-8 by the bulky tryptophan side chain. The (R)-2-(biphenyl-4-ylsulfonyl)-1,2,3, 4-tetrahydroisochinolin-3-carboxylic acid, a conformationally constrained D-Tic derivative, accommodates its biphenyl substituent into the deep primary specificity S(1)' subsite, inducing a widening of the entrance to this pocket; this modification of the protein, mainly consisting in a shift of the segment centered at Pro217, is observed for the first time in MMP-8 complexes. Cation-aromatic interactions can stabilize the formation of both complexes, and the beneficial effect of aromatic substituents in proximity of the catalytic zinc ion is discussed. The phosphonate group bound to either a primed- or unprimed-side inhibitor maintains the same relative position with respect to the catalytic zinc ion, suggesting that this binding function can be exploited for the design of combined inhibitors assembled to interact with both primed and unprimed regions of the active cleft.

Protease inhibitors. Part 12. Synthesis of potent matrix metalloproteinase and bacterial collagenase inhibitors incorporating sulfonylated N-4-nitrobenzyl-beta-alanine hydroxamate moieties

N-4-Nitrobenzyl-beta-alanine was reacted with alkyl/arylsulfonyl halides, followed by conversion of the COOH to the CONHOH group. Structurally related compounds were obtained by reaction of N-4-nitrobenzyl-beta-alanine with aryl isocyanates, arylsulfonyl isocyanates or benzoyl isothiocyanate, followed by similar conversion of the COOH into the CONHOH moiety. Another subseries of derivatives was prepared from sulfanilyl- or metanilyl-4-nitrobenzyl-beta-alanine by reaction with arylsulfonyl isocyanates, followed by the introduction of the hydroxamate moiety. The new compounds were assayed as inhibitors of four matrix metalloproteinases (MMPs), MMP-1, MMP-2, MMP-8 and MMP-9, and of the Clostridium histolyticum collagenase (ChC). Some of the prepared hydroxamate derivatives proved to be very effective collagenase/gelatinase inhibitors, depending on the substitution pattern at the sulfonamido moiety. Substitutions leading to the best inhibitors of MMP-1, a short-pocket enzyme, were those involving pentafluorophenylsulfonyl or 3-trifluoromethyl-phenylsulfonyl at P(1') (K(I) of 3-5 nM). For MMP-2, MMP-8 and MMP-9 (deep-pocket enzymes), the best inhibitors were those containing perfluoroalkylsulfonyl- and substituted-arylsulfonyl moieties, such as pentafluorophenylsulfonyl, 3- and 4-protected-aminophenylsulfonyl-, 3- and 4-carboxy-phenylsulfonyl-, arylsulfonylureido- or arylsulfonylureido-sulfanilyl-/metanilyl moieties at P(1'). Bulkier groups in this position, such as 1- and 2-naphthyl-, substituted-naphthyl or quinoline-8-yl- moieties, among others, led to less effective MMP/ChC inhibitors. The best ChC inhibitors were again those containing pentafluorophenylsulfonyl, 3- and 4-protected-aminophenylsulfonyl P(1') groups. This study demonstrates that the 4-nitrobenzyl moiety, investigated here for the first time, is an efficient P(2') anchoring moiety, whereas the beta-alanyl scaffold can successfully replace the alpha-amino acyl one, for obtaining potent MMP/ChC inhibitors.

Protease inhibitors: synthesis of potent bacterial collagenase and matrix metalloproteinase inhibitors incorporating N-4-nitrobenzylsulfonylglycine hydroxamate moieties

A series of compounds was prepared by reaction of alkyl/arylsulfonyl halides with N-4-nitrobenzylglycine, followed by conversion of the COOH to the CONHOH group, with hydroxylamine in the presence of carbodiimides. Other structurally related compounds were obtained by reaction of N-4-nitrobenzylglycine with aryl isocyanates, arylsulfonyl isocyanates, or benzoyl isothiocyanate, followed by the similar conversion of the COOH into the CONHOH moiety. Another subseries of derivatives was prepared from sulfanilyl- or metanilyl-4-nitrobenzylglycine by reaction with arylsulfonyl isocyanates, followed by conversion of the COOH to the hydroxamate moiety. The new compounds were assayed as inhibitors of four matrix metalloproteinases (MMPs), MMP-1, MMP-2, MMP-8, and MMP-9, and of the Clostridium histolyticum collagenase (ChC). Some of the prepared hydroxamate derivatives proved to be very effective collagenase/gelatinase inhibitors, depending on the substitution pattern at the sulfonamido moiety. Substitutions leading to best inhibitors of MMP-1, a short pocket enzyme, were those involving pentafluorophenylsulfonyl or 3-trifluoromethylphenylsulfonyl moieties at P(1') (K(I)'s of 3-5 nM). For MMP-2, MMP-8, and MMP-9 (deep-pocket enzymes), best inhibitors were especially those containing long perfluoroalkylsulfonyl and substituted-arylsulfonyl moieties, such as pentafluorophenylsulfonyl, 3- and 4-protected-aminophenylsulfonyl, 3- and 4-carboxyphenylsulfonyl, arylsulfonylureido, or arylsulfonylureidosulfanilyl/metanilyl moieties, at P(1'). Bulkier groups in this position, such as 1- and 2-naphthyl, substituted-naphthyl, or quinolin-8-yl moieties among others, led to less effective MMP/ChC inhibitors. Best ChC inhibitors were again those containing pentafluorophenylsulfonyl or 3- and 4-protected-aminophenylsulfonyl P(1') anchoring groups, suggesting that this protease is also a short-pocket wider-neck one (more similar to MMP-1). This study also proves that the 4-nitrobenzyl moiety is an efficient P(2') anchoring moiety and that sulfonylureido, ureido, or carboxythioureido substitutions at P(1') are also tolerated for obtaining potent sulfonylated amino acid hydroxamate-like MMP/ChC inhibitors.

Protease inhibitors - part 5. Alkyl/arylsulfonyl- and arylsulfonylureido-/arylureido- glycine hydroxamate inhibitors of Clostridium histolyticum collagenase

Reaction of alkyl/arylsulfonyl halides with glycine afforded a series of derivatives which were first N-benzylated by treatment with benzyl chloride, and then converted to the corresponding hydroxamic acids with hydroxylamine in the presence of carbodiimide derivatives. Other derivatives were obtained by reaction of N-benzyl-glycine with aryl isocyanates, arylsulfonyl isocyanates or benzoyl isothiocyanate, followed by conversion of their COOH group into the CONHOH moiety, as mentioned above. The 90 new compounds reported here were assayed as inhibitors of the Clostridium histolyticum collagenase (EC 3.4.24.3), a zinc enzyme which degrades triple helical regions of native collagen. The prepared hydroxamate derivatives were generally 100-500 times more active than the corresponding carboxylates. In the series of synthesized hydroxamates, substitution patterns leading to the best inhibitors were those involving perfluoroalkylsulfonyl- and substituted-arylsulfonyl moieties, such as pentafluorophenylsulfonyl, 3- and 4-carboxyphenylsulfonyl-, 3-trifluoromethyl-phenylsulfonyl or 1- and 2-naphthyl among others. Thus, it seems that similarly to the matrix metalloproteinase (MMP) hydroxamate inhibitors, Clostridium histolyticum collagenase inhibitors should incorporate hydrophobic moieties at the P(1') and P(2') sites, whereas the alpha-carbon substituent may be a small and compact moiety (such as H, for the Gly derivatives reported here). Such compounds might lead to the design of collagenase inhibitor-based drugs useful as anti-cancer, anti-arthritis or anti-bacterial agents for the treatment of corneal keratitis.

Protease inhibitors. Part 7. Inhibition of Clostridium histolyticum collagenase with sulfonylated derivatives of L-valine hydroxamate

Sulfonylated L-valine hydroxamate derivatives were obtained by reaction of alkyl/arylsulfonyl halides with the title amino acid, followed by treatment with benzyl chloride, and conversion of the COOH moiety to the CONHOH group. Other derivatives were obtained by reaction of N-benzyl-L-valine with arylisocyanates, arylsulfonylisocyanates or benzoylisothiocyanate, followed by the similar conversion of the COOH into the CONHOH moiety, with hydroxylamine in the presence of carbodiimides. The obtained compounds were assayed as inhibitors of the Clostridium histolyticum collagenase, ChC (EC 3.4.24.3), a zinc enzyme which degrades triple helical collagen. The hydroxamate derivatives were generally 100-500 times more active than the corresponding carboxylates. In the series of synthesized derivatives, substitution patterns leading to best ChC inhibitors were those involving perfluoroalkylsulfonyl- and substituted-arylsulfonyl moieties, such as pentafluorophenylsulfonyl; 3- and 4-protected-aminophenylsulfonyl-; 3- and 4-carboxyphenylsulfonyl-; 3-trifluoromethylphenylsulfonyl; or 1- and 2-naphthyl among others. Similarly to the matrix metalloproteinase hydroxamate inhibitors, ChC inhibitors of the type reported here must incorporate hydrophobic moieties at the P(2') and P(3') subsites, in order to achieve tight binding to the enzyme. Such compounds might lead to drugs useful in the treatment corneal bacterial keratitis.

Protease inhibitors. Part 8: synthesis of potent Clostridium histolyticum collagenase inhibitors incorporating sulfonylated L-alanine hydroxamate moieties

A series of hydroxamates was prepared by reaction of alkyl/arylsulfonyl halides with N-2-chlorobenzyl-L-alanine, followed by conversion of the COOH moiety to the CONHOH group, with hydroxylamine in the presence of carbodiimides. Other structurally related compounds were obtained by reaction of N-2-chlorobenzyl-L-alanine with aryl isocyanates, arylsulfonyl isocyanates or benzoyl isothiocyanate, followed by the similar conversion of the COOH into the CONHOH moiety. The new compounds were assayed as inhibitors of the Clostridium histolyticum collagenase, ChC (EC 3.4.24.3), a bacterial zinc metallo-peptidase which degrades triple helical collagen as well as a large number of synthetic peptides. The prepared hydroxamate derivatives proved to be 100-500 times more active collagenase inhibitors than the corresponding carboxylates. Substitution patterns leading to best ChC inhibitors (both for carboxylates as well as for the hydroxamates) were those involving perfluoroalkylsulfonyl- and substituted-arylsulfonyl moieties, such as pentafluorophenylsulfonyl; 3- and 4-protected-aminophenylsulfonyl-; 3- and 4-carboxyphenylsulfonyl-; 3-trifluoromethyl-phenylsulfonyl; as well as 1- and 2-naphthyl-, quinoline-8-yl- or substituted-arylsulfonylamidocarboxyl moieties among others. Similarly to the matrix metalloproteinase (MMP) hydroxamate inhibitors, ChC inhibitors of the type reported here must incorporate hydrophobic moieties at the P2' and P3' sites, in order to achieve tight binding to the enzyme. This study also proves that the 2-chlorobenzyl moiety, investigated here for the first time, is an efficient P2' anchoring moiety for obtaining potent ChC inhibitors.