Category: L. Vezenkov

12/10-Helix in Mixed β-Peptides Alternating Bicyclic and Acyclic β-Amino Acids: Probing the Relationship between Bicyclic Side Chain and Helix Stability

Chemistry. 2018 Dec 12. doi: 10.1002/chem.201804404. Epub 2018 Nov 15

Simon M, Milbeo P, Liu H, André C, Wenger E, Martinez J, Amblard M, Aubert E, Legrand B, Calmès M.


12/10-Helices constitute suitable templates that can be used to design original structures. Nevertheless, they often suffer from a weak stability in polar solvents because they exhibit a mixed hydrogen-bond network resulting in a small macrodipole. In this work, stable and functionalizable 12/10-helices were developed by alternating a highly constrained β2, 3, 3 -trisubstituted bicyclic amino acid (S)-1-aminobicyclo[2.2.2]octane-2-carboxylic acid ((S)-ABOC) and an acyclic substituted β-homologated proteinogenic amino acid (l-β3 -hAA). Based on NMR spectroscopic analysis, it was shown that such mixed β-peptides display well-defined right-handed 12/10-helices in polar, apolar, and chaotropic solvents; that are, CD3 OH, CDCl3 , and [D6 ]DMSO, respectively. The stability of the hydrogen bonds forming the C10 and C12 pseudocycles as well as the benefit provided by the use of the constrained bicyclic ABOC versus typical acyclic β-amino acids sequences when designing 12/10-helix were investigated using NH/ND NMR exchange experiments and DFT calculations in various solvents. These studies showed that the β3 -hAA/(S)-ABOC helix displayed a more stable hydrogen-bond network through specific stabilization of the C10 pseudocycles involving the bridgehead NH of the ABOC bicyclic scaffold.

A new quinoline-based chemical probe inhibits the autophagy-related cysteine protease ATG4B

 2018 Aug 3;8(1):11653. doi: 10.1038/s41598-018-29900-x.

Bosc D, Vezenkov L, Bortnik S, An J, Xu J, Choutka C, Hannigan AM, Kovacic S, Loo S, Clark PGK, Chen G, Guay-Ross RN, Yang K, Dragowska WH, Zhang F, Go NE, Leung A, Honson NS, Pfeifer TA, Gleave M, Bally M, Jones SJ, Gorski SM, Young RN.


The cysteine protease ATG4B is a key component of the autophagy machinery, acting to proteolytically prime and recycle its substrate MAP1LC3B. The roles of ATG4B in cancer and other diseases appear to be context dependent but are still not well understood. To help further explore ATG4B functions and potential therapeutic applications, we employed a chemical biology approach to identify ATG4B inhibitors. Here, we describe the discovery of 4-28, a styrylquinoline identified by a combined computational modeling, in silico screening, high content cell-based screening and biochemical assay approach. A structure-activity relationship study led to the development of a more stable and potent compound LV-320. We demonstrated that LV-320 inhibits ATG4B enzymatic activity, blocks autophagic flux in cells, and is stable, non-toxic and active in vivo. These findings suggest that LV-320 will serve as a relevant chemical tool to study the various roles of ATG4B in cancer and other contexts

Ribbon-like Foldamers for Cellular Uptake and Drug Delivery

Chembiochem 2017 Nov 2;18(21):2110-2114. doi: 10.1002/cbic.201700455. Epub 2017 Sep 22.

Vezenkov LL, Martin V, Bettache N, Simon M, Messerschmitt A, Legrand B, Bantignies JL, Subra G, Maynadier M, Bellet V, Garcia M, Martinez J, Amblard M.


Different intracellular delivery systems of bioactive compounds have been developed, including cell-penetrating peptides. Although usually nontoxic and biocompatible, these vectors share some of the general drawbacks of peptides, notably low bioavailability and susceptibility to protease degradation, that limit their use. Herein, the conversion of short peptide sequences into poly-α-amino-γ-lactam foldamers that adopt a ribbon-like structure is investigated. This template is used to distribute critical cationic and/or hydrophobic groups on both sides of the backbone, leading to potent short, cell-permeable foldamers with a low positive-charge content. The lead compound showed dramatically improved protease resistance and was able to efficiently deliver a biologically relevant cargo inside cells. This study provided a simple strategy to convert short peptide sequences into efficient protease-resistant cell-penetrating foldamers.

Structure-Activity Relationships of JMV4463, a Vectorized Cathepsin D Inhibitor with Antiproliferative Properties: The Unique Role of the AMPA-Based Vector

ChemMedChem, 2016, Volume: 11, Issue: 3, Pages: 302-308, DOI: 10.1002/cmdc.201500457

L. Vezenkov, C. A. Sanchez, V. Bellet, V. Martin, M. Maynadier, N. Bettache, V. Lisowski, J. Martinez, M. Garcia, M. Amblard, J. F. Hernandez


Cathepsin D (CathD) is overexpressed and secreted by several solid tumors and stimulates their growth, the mechanism of which is still not understood.  In this context, the pepstatin bioconjugate JMV4463 [Ac-arg-O2Oc-(Val)3-Sta-Ala-Sta-(AMPA)4-NH2; O2Oc=8-amino-3,6-dioxaoctanoyl, Sta=statine, AMPA=ortho-aminomethylphenylacetyl], contg. a new kind of cell-penetrating vector, was previously shown to exhibit potent antiproliferative effects in vitro and to delay the onset of tumors in vivo.  In this study, the authors performed a structure-activity relationship anal. to evaluate the significance of the inhibitor and vector moieties of JMV4463.  By modifying both statine residues of pepstatin the authors found that the antiproliferative activity is correlated with CathD inhibition, supporting a major role of the catalytic activity of intracellular CathD in cancer cell proliferation.  Replacing the vector composed of four AMPA units with other vectors was found to abolish cytotoxicity, although all of the conjugates enabled pepstatin transport into cells.  In addn., the AMPA4 vector must be localized at the C terminus of the bioconjugate.  The unexpected importance of the vector structure and position for cytotoxic action suggests that AMPA4 enables pepstatin to inhibit the proteolysis of crit. CathD substrates involved in cell proliferation via a unique mechanism of action.

Turning Peptide Sequences into Ribbon Foldamers by a Straightforward Multicyclization Reaction

Angewandte Chemie, International Edition, 2015, Volume: 54, Issue: 47, Pages: 13966-13970, DOI: 10.1002/anie.201506955

V. Martin, B. Legrand, L. L. Vezenkov, M. Berthet, G. Subra, M. Calmes, J-L. Bantignies, J. Martinez, M. Amblard


The conformational control of mol. scaffolds allows the display of functional groups in defined spatial arrangement.  This is of considerable interest for developing fundamental and applied systems in both the fields of biol. and material sciences.  Peptides afford a large diversity of functional groups, and peptide synthetic routes are very attractive and accessible.  However, most short peptides do not possess well-defined secondary structures.  Herein, we developed a simple strategy for converting peptide sequences into structured γ-lactam-contg. oligomers while keeping the amino acids side chain diversity.  We showed the propensity of these mols. to adopt ribbon-like secondary structures.  The periodic distribution of the functional groups on both sides of the ribbon plane is encoded by the initial peptide sequence.

Dipeptide mimic oligomer transporter mediates intracellular delivery of Cathepsin D inhibitors: a potential target for cancer therapy

J Control Release. 2013 Oct 28;171(2):251-7. doi: 10.1016/j.jconrel.2013.07.017. Epub 2013 Jul 27.

Maynadier M, Vezenkov LL, Amblard M, Martin V, Gandreuil C, Vaillant O, Gary-Bobo M, Basile I, Hernandez JF, Garcia M, Martinez J.


Implication of the intracellular proteolytic activity of Cathepsin D (CathD), a lysosomal aspartyl-protease overexpressed in numerous solid tumors, has been evidenced on tumor growth. Its intracellular inhibition by potent inhibitors such as pepstatin constitutes a relevant but challenging molecular target. Indeed the potential of pepstatin as a therapeutic molecule is hampered by its too low intracellular penetration. We addressed this limitation by designing and developing a bioconjugate combining a pepstatin derivative with a new vector of cell penetration (CPNP) specifically targeting the endolysosomal compartment. We showed that this pepstatin conjugate (JMV4463) exhibited high anti-proliferative effect on tumor cell cultures via intracellular CathD inhibition and altered cell cycle associated with apoptotic events in vitro. When tested in mice xenografted with breast cancer cells, JMV4463 delayed tumor emergence and growth.

Helical oligomers of thiazole-based γ-amino acids: synthesis and structural studies

Angew Chem Int Ed Engl. 2013 Jun 3;52(23):6006-10. doi: 10.1002/anie.201302106

Mathieu L, Legrand B, Deng C, Vezenkov L, Wenger E, Didierjean C, Amblard M, Averlant-Petit MC, Masurier N, Lisowski V, Martinez J, Maillard LT


9-Helix: 4-Amino(methyl)-1,3-thiazole-5-carboxylic acids (ATCs) were synthesized as new γ-amino acid building blocks. The structures of various ATC oligomers were analyzed in solution by CD and NMR spectroscopy and in the solid state by X-ray crystallography. The ATC sequences adopted a well-defined 9-helix structure in the solid state and in aprotic and protic organic solvents as well as in aqueous solution.