Category: N. Masurier

Site-specific grafting on titanium surfaces with hybrid temporin antibacterial peptides

J. Mater. Chem. B, 2018,6, 1782-1790. doi 10.1039/C8TB00051D


Relying on a membrane-disturbing mechanism of action and not on any intracellular target, antimicrobial peptides (AMP) are attractive compounds to be grafted on the surface of implantable materials such as silicone catheters or titanium surgical implants. AMP sequences often display numerous reactive functions (e.g. amine, carboxylic acid) on their side chains and straightforward conjugation chemistries could lead to uncontrolled covalent grafting, random orientation, and non-homogenous density. To achieve an easy and site specific covalent attachment of unprotected peptides on titanium surfaces, we designed hybrid silylated biomolecules based on the temporin-SHa amphipathic helical antimicrobial sequence. With the grafting reaction being chemoselective, we designed five analogues displaying the silane anchoring function at the N-ter, C-ter or at different positions inside the sequence to get an accurate control of the orientation. Grafting density calculations were performed by XPS and the influence of the orientation of the peptide on the surface was clearly demonstrated by the measure of antimicrobial activity. Temporin amphipathic helices are described to permeabilize the bacterial membrane by interacting in a parallel orientation with it. Our results move in the direction of this mechanism as the selective grafting of hybrid temporin 2 through a lysine placed at the center of the peptide sequence, resulted in better biofilm growth inhibition of E. coli and S. epidermis than substrates in which temporins were grafted via their C- or N-terminus.

Inhibitors of kallikrein-related peptidases: An overview.

Med Res Rev. 2018 Mar;38(2):655-683. doi: 10.1002/med.21451.

Masurier N, Arama DP, El Amri C, Lisowski V.


Kallikrein-related peptidases (KLKs) are a family of 15 secreted serine proteases that are involved in various physiological processes. Their activities are subtly regulated by various endogenous inhibitors, ranging from metallic ions to macromolecular entities such as proteins. Furthermore, dysregulation of KLK activity has been linked to several pathologies, including cancer and skin and inflammatory diseases, explaining the numerous efforts to develop KLK-specific pharmacological inhibitors as potential therapeutic agents. In this review, we focus on the huge repertoire of KLKs inhibitors reported to date with a special emphasis on the diversity of their molecular mechanisms of inhibition.

C9/12 Ribbon-Like Structures in Hybrid Peptides Alternating α- and Thiazole-Based γ-Amino Acids

Chemistry. 2017 Dec 11;23(69):17584-17591. doi: 10.1002/chem.201704001. Epub 2017 Nov 15.

Bonnel C, Legrand B, Simon M, Martinez J, Bantignies JL, Kang YK, Wenger E, Hoh F, Masurier N, Maillard LT.


According to their restricted conformational freedom, heterocyclic γ-amino acids are usually considered to be related to Z-vinylogous γ-amino acids. In this context, oligomers alternating α-amino acids and thiazole-based γ-amino acids (ATCs) were expected to fold into a canonical 12-helical shape as described for α/γ-hybrid peptides composed of cis-α/β-unsaturated γ-amino acids. However, through a combination of X-ray crystallography, NMR spectroscopy, FTIR experiments, and DFT calculations, it was determined that the folding behavior of ATC-containing hybrid peptides is much more complex. The homochiral α/(S)-ATC sequences were unable to adopt a stable conformation, whereas the heterochiral α/(R)-ATC peptides displayed novel ribbon structures stabilized by unusual C9/12 -bifurcated hydrogen bonds. These ribbon structures could be considered as a succession of pre-organized γ/α dipeptides and may provide the basis for designing original α-helix mimics.

FT-IR and NMR structural markers for thiazole-based γ-peptide foldamers

Organic & Biomolecular Chemistry, 2016, Volume: 14, Issue: 37, Pages: 8664-8669, DOI: 10.1039/C6OB01594H

C. Bonnel, B. Legrand, J. L. Bantignies, H. Petitjean, J. Martinez, N. Masurier, L. T. Maillard 


In the search of new robust and environmental-friendly anal. methods able to answer quant. issues in pharmacol., we explore liq. chromatog. (LC) assocd. with elemental mass spectrometry (ICP-MS) to monitor peptides in such complex biol. matrixes.  The novelty is to use mass spectrometry to replace radiolabelling and radioactivity measurements, which represent up-to now the gold std. to measure org. compd. concns. in life science.  As a proof of concept, we choose the vasopressin (AVP)/V1A receptor system for model pharmacol. assays.  The capacity of ICP-MS to provide highly sensitive quantitation of metallic and hetero elements, whatever the sample medium, prompted us to investigate this technique in combination with appropriate labeling of the peptide of interest.  Selenium, that is scarcely present in biol. media, was selected as a good compromise between ICP-MS response, covalent tagging ability using conventional sulfur chem. and peptide detection specificity.  Applying selenium monitoring by elemental mass spectrometry in pharmacol. is challenging due to the very high salt content and org. material complexity of the samples that produces polyat. aggregates and thus potentially mass interferences with selenium detection.  Hyphenation with a chromatog. sepn. was found compulsory.  Noteworthy, we aimed to develop a straightforward quant. protocol that can be performed in any lab. equipped with a std. macrobore LC-ICP-MS system, in order to avoid time-consuming sample treatment or special implementation of instrumental set-up, while allowing efficient suppression of all mass interferences to reach the targeted sensitivity.  Significantly, a quantification limit of 57 ng Se L-1 (72 fmol of injected Se) was achieved, the samples issued from the pharmacol. assays being directly introduced into the LC-ICP-MS system.  The established method was successfully validated and applied to the measurement of the vasopressin ligand affinity for its V1A receptor through the detn. of the dissocn. const. (Kd) which was compared to the one recorded with conventional radioactivity assays.

Imidazopyridine-fused [1,3]-diazepinones part 2: Structure-activity relationships and antiproliferative activity against melanoma cells

European Journal of Medicinal Chemistry, 2016, Volume: 125, Pages: 1225-1234, DOI: 10.1016/j.ejmech.2016.11.023

V. Bellet, L. Lichon, D. P. Arama, A. Gallud,  V. Lisowski, L. T. Maillard, M. Garcia, J. Martinez, N. Masurier

Diapositive 1


We recently described a pyrido-imidazodiazepinone deriv. which could be a promising hit compd. for the development of new drugs acting against melanoma cells. In this study, a series of 28 novel pyrido-imidazodiazepinones were synthesized and screened for their in vitro cytotoxic activities against the melanoma MDA-MB-435 cell line. Among the derivs., seven of them showed 50% growth inhibitory activity at 1 μM concn., and high selectivity against the melanoma cell line MDA-MB-435.

Pyrido-imidazodiazepinones as a new class of reversible inhibitors of human kallikrein 7

European Journal of Medicinal Chemistry, 2015, Volume: 93, Pages: 202-213, DOI: 10.1016/j.ejmech.2015.02.008

D. P. Arama, F. Soualmia, V. Lisowski, J.-F. Longevial, E. Bosc, L. T. Maillard, J. Martinez, N. Masurier, C. El Amri


The human tissue kallikrein-7 (KLK7) is a chymotryptic serine protease member of tissue kallikrein family.  KLK7 is involved in skin homeostasis and inflammation.  Excess of KLK7 activity is also assocd. with tumor metastasis processes, esp. in ovarian carcinomas, prostatic and pancreatic cancers.  Development of Kallikrein 7 inhibitors is thus of great interest in oncol. but also for treating skin diseases.  Most of the developed synthetic inhibitors present several drawbacks such as poor selectivity and unsuitable physico-chem. properties for in vivo use.  Recently, the authors described a practical sequence for the synthesis of imidazopyridine-fused [1,3]-diazepines.  Here, the authors report the identification of pyrido-imidazodiazepinone core as a new potential scaffold to develop selective and competitive inhibitors of kallikrein-related peptidase 7.  Structure-activity relationships (SAR), inhibition mechanisms and selectivity as well as cytotoxicity against selected cancer cell lines were investigated.

Cross-Claisen condensation of N-Fmoc-amino acids – a short route to heterocyclic γ-amino acids

European Journal of Organic Chemistry, 2015, Volume: 2015, Issue: 10, Pages: 2262-2270, DOI: 10.1002/ejoc.201500012

L. Mathieu, C. Bonnel, N. Masurier, L. T. Maillard, J. Martinez, V. Lisowski


4-Amino(methyl)-1,3-thiazole-5-carboxylic acids (ATCs) are a new class of constrained heterocyclic γ-amino acids built around a thiazole ring; these compds. are valuable as design mimics of the secondary structures of proteins such as helixes, β-sheets, turns, and β-hairpins.  We report herein a short and versatile chem. route to orthogonally protected ATCs.  The synthesis is centered on cross-Claisen condensations between N-Fmoc-amino acids and sterically hindered 1,1-dimethylallyl acetate.  The optimized conditions are compatible with aliph., arom., acidic, and basic amino acids.  The resulting N-Fmoc-β-keto ester intermediates were engaged in a two-step process to give ATCs in 45-90 % yields.  The synthetic protocol provides a highly flexible method for the introduction of a wide variety of lateral chains either on the γ-carbon atom or on the thiazole core of the γ-amino acids.

Solid-supported synthesis and 5-HT7/5-HT1A receptor affinity of arylpiperazinylbutyl derivatives of 4,5-dihydro-1,2,4-triazine-6-(1H)-one

Chemical Biology & Drug Design, 2015, Volume: 86, Issue: 4, Pages: 697-703,  DOI: 10.1111/cbdd.12539

K. Grychowska, N. Masurier, P. Verdie, G. Satala, A. J. Bojarski, J. Martinez,  M. Pawlowski, G. Subra, P. Zajdel


A series of arylpiperazinylbutyl derivs. I [R1 = H, 2-OMe, 2-SMe, 2-F, 4-Cl, 2,3-diCl; R2 = Ph, 2-ClC6H4, cyclohexyl] of 4,5-dihydro-1,2,4-triazine-6(1H)-ones was designed and synthesized according to the new solid-supported methodol.  In this approach, triazinone scaffold was constructed from the fmoc-protected glycine.  The library representatives showed different levels of affinity for 5-HT7 and 5-HT1A receptors, among which compds. I [R1 = 2-SMe, 2-F; R2 = Ph and R1 = 2-OMe, 2-SMe, 2,3-diCl; R2 = cyclohexyl] were classified as dual 5-HT7/5-HT1A receptors ligands.  The structure-affinity relationship anal. revealed that receptor affinity and selectivity of the tested compds. depended on the kind of substituent in position 3 of triazinone fragment as well as substitution pattern of phenylpiperazine moiety.

Synthesis of Thieno[3,2-e][1,4]diazepin-2-ones: Application of an Uncatalysed Pictet-Spengler Reaction

European Journal of Organic Chemistry, 2015, Volume: 2015, Issue: 32, Pages: 7146-7153, DOI: 10.1002/ejoc.201500943

S. Denoyelle, G. Tambutet, N. Masurier, L. T. Maillard, J. Martinez, V. Lisowski


A series of 5-substituted thieno[3,2-e][1,4]diazepin-2-ones was synthesized in four steps from Me 3-aminothiophene-2-carboxylate.  After the coupling of 3-aminothiophene with α-amino acids, the key final step that involves an uncatalyzed Pictet-Spengler reaction allowed the cyclization of the seven-membered diazepinone ring.  The reaction was first optimized and then exemplified in three different series (phenylalanine, alanine and proline) that led to 24 target diazepinones, which includes 19 optically pure diastereomers.

Imidazopyridine-fused [1,3]-diazepinones: Synthesis and antiproliferative activity

European Journal of Medicinal Chemistry, 2014, Volume: 75, Pages: 382-390,  DOI: 10.1016/j.ejmech.2014.01.044

A. Gallud, O. Vaillant, L.T. Maillard, D. Arama, J. Dubois, M. Maynadier, V. Lisowski, M. Garcia, J. Martinez, N. Masurier


A series of 15 pyrido-imidazo-1,3-diazepin-5-ones and pyrido-1,3-diazepine-2,5-diones were synthesized and their anticancer activities were evaluated.  Among tested compds. on a cell lines panel, compd. I presents the best growth inhibition activity on 21 cell lines with a cytotoxic effect on MDA-MB-435 melanoma cells.  This compd. led to deep cell morphol. changes and revealed to be an inhibitor of the Hepatocyte progenitor kinase-like kinase (HGK), which is known to be implicated in the migration, adhesion and invasion of various tumor cells.