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Xavier Maréchal,
Emilie Genin,
Lixian Qin,
Olivier Sperandio,
Mathieu Montes,
Nicolas Basse,
Nicolas Richy,
Maria A Miteva,
Michèle Reboud-Ravaux, Joëlle Vidal,
Bruno O Villoutreix
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ABSTRACT: Although several constitutive proteasome inhibitors have been reported these recent years, potent organic, non-covalent and readily available inhibitors are still poorly documented. Here we used a structure- and ligand-based in silico approach to identify commercially available 1,2,4-oxadiazole derivatives as non-covalent human 20S proteasome inhibitors. Their optimization led to the newly synthesized compound 4h that is a mixed proteasomal inhibitor of the chymotrypsin-like activity (Ki of 26,1 nM and K'i of 7.5 nM) which is in addition selective versus the challenging cathepsin B and calpain proteases. Molecular modeling studies corroborated the mechanism of inhibition and suggest an unusual binding of the inhibitor within the S5 binding pocket (β6 subunit). The cellular effects of our compounds validate their utility as potential pharmacological agents for anti-cancer pre-clinical studies.
Current Medicinal Chemistry 03/2013; · 4.86 Impact Factor
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ABSTRACT: We exploited the concept of polyvalent interactions to produce highly selective and efficient inhibitors of eukaryotic proteasome. This multicatalytic protease with the unique topography of its 6 active sites has emerged as a promising target to treat cancer with the use of the covalent inhibitor bortezomib. We used our reference noncovalent inhibitor, a selective TMC-95A tripeptide linear mimic, to design dimeric noncovalent proteasome inhibitors that target two active sites simultaneously. We synthesized pegylated monomer and dimers of the reference inhibitor and evaluated their capacity to inhibit a mammalian 20S proteasome. The inhibitory power of the dimers depended on the average length of their spacer. Lineweaver-Burk double-reciprocal plots indicated competitive inhibition. The best dimer inhibited CT-L activity 800-times more efficiently than the reference inhibitor.
European journal of medicinal chemistry 03/2012; 52:322-7. · 3.27 Impact Factor
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Michael Groll,
Nerea Gallastegui,
Xavier Maréchal,
Virginie Le Ravalec,
Nicolas Basse,
Nicolas Richy,
Emilie Genin,
Robert Huber,
Luis Moroder, Joëlle Vidal,
Michèle Reboud-Ravaux
ChemMedChem 10/2010; 5(10):1701-5. · 3.15 Impact Factor
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ABSTRACT: Proteasome inhibition is a promising strategy for treating cancers. Herein, we report the discovery of novel drug-like inhibitors of mammalian proteasome 20S using a multistep structure-based virtual ligand screening strategy. Sulfone- or piperazine-containing hits essentially belong to the under-represented class of noncovalent and nonpeptidic proteasome inhibitors. Several of our compounds act in the micromolar range and are cytotoxic on human tumoral cell lines. Optimization of these molecules could lead to better anticancer therapy.
Journal of Medicinal Chemistry 11/2009; 53(1):509-13. · 4.80 Impact Factor
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ABSTRACT: We have designed and evaluated 45 linear analogues of the natural constrained cyclopeptide TMC-95A. These synthetically less demanding molecules are based on the tripeptide sequence Y-N-W of TMC-95A. Structural variations in the amino acid side chains and termini greatly influenced both the efficiency and selectivity of action on a given type of active site. Inhibition constants were submicromolar (Ki approximately 300 nM) despite the absence of the entropically favorable constrained conformation that is characteristic of TMC-95A and its cyclic analogues. These linear compounds were readily prepared and reasonably stable in culture medium and could be optimized to inhibit one, two, or all three proteasome catalytic sites. Cytotoxicity assays performed on a series of human tumor cell lines identified the most potent inhibitors in cells.
Journal of Medicinal Chemistry 07/2007; 50(12):2842-50. · 5.25 Impact Factor
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ABSTRACT: A general two-step preparation of enantiopure N(alpha),N(beta)-orthogonally diprotected alpha-hydrazino acids 1 is developed on a multigram scale. The key reaction is the efficient electrophilic amination of N-benzyl amino acids 6 with N-Boc-oxaziridine 7 and accommodates various functional groups encountered in side chains of amino acids. The cyclic 2,3,4,5-tetrahydro-3-pyridazine carboxylic acid (piperazic acid) derivatives 2 and 3 or the cyclic 3,4-dihydro-3-pyrazolecarboxylate 4 are conveniently prepared from glutamic acid or aspartic acid via orthogonally diprotected alpha-hydrazino acids 1m and 1n.
The Journal of Organic Chemistry 05/2004; 69(7):2367-73. · 4.45 Impact Factor
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ABSTRACT: The synthesis of three constrained macrocyclic peptide analogues 1 of TMC-95A as potential proteasome inhibitors is described. The key step involves a Ni(0)-mediated macrocyclization of tripeptides 2 bearing halogenated aromatic side chains for the formation of the biaryl junction. In addition, an enantioselective preparation of l-7-bromotryptophan methyl ester 3 using a Corey-O'Donnell alkylation of the glycine benzophenone imine was achieved in good overall yield with very high ee (>85%) on a multigram scale.
The Journal of Organic Chemistry 12/2003; 68(25):9835-8. · 4.45 Impact Factor
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ABSTRACT: The name hydrazinopeptide designates peptidic structures in which one of the native CONH links is replaced by a CONHNH (hydrazido) fragment. In this paper, we report the synthesis of such hydrazinohexapeptides (3−5) analogous to Z-Ala-Ala-Pro-Val-Ala-Ala-NHiPr (6), a substrate of human leukocyte elastase (HLE; EC 3.4.21.37), cleaved by this serine protease between the Val4 and Ala5 residues. In hydrazinopeptides 3−5, the Ala5, Val4, or Pro3 residue, respectively, of the model peptide, has been replaced by the corresponding α-l-hydrazino acid. In 3, the bond likely to be cleaved by HLE is the one involving the CONHNH link, while in 4 and 5, this link is normally shifted away by one or two amino acid units from the catalytic serine. On incubation with HLE, hydrazinopeptide 3 proved to be a substrate and was cleaved between Val4 and NHAla5, like peptide 6. In contrast, 4 and 5 proved to bind to HLE without being cleaved, featuring properties consistent with reversible competitive inhibition. General guidelines for the synthesis of hydrazinopeptides are also reported in this paper. These guidelines take into account the chemical specificity of hydrazino acids, while being fully compatible with the conventional peptide coupling techniques. The utilization of orthogonally bisprotected hydrazino acids 1 where the Nβ and Nα atoms bear a Boc and a Bzl group, respectively, is recommended for the easy construction of such hydrazinopeptides.
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