Publications

  • Article dans une revue
  • Antibody-Vincristine Conjugates as Potent Anticancer Therapeutic Agents

    Agathe Boos, Julien Most, Héloïse Cahuzac, Louis Moreira da Silva, François Daubeuf, Stéphane Erb, Sarah Cianférani, Oscar Hernandez-Alba, Constantin Semenchenko, Igor Dovgan, Sergii Kolodych, Alexandre Detappe, Françoise Dantzer, Alain Wagner, Maria Zeniou, Guilhem Chaubet
    Journal of Medicinal Chemistry, 2024, ⟨10.1021/acs.jmedchem.4c02425⟩
    Article dans une revue

    Antibody drug-conjugates (ADC) are a well-established class of therapeutics primarily used in oncology to selectively deliver highly cytotoxic agents into cancer cells. While ADC should theoretically spare healthy tissues and diminish side effects in patients, off-target toxicity is still observed, all the more serious as the drugs are extremely potent. In the quest towards safer payloads, we used the conventional chemotherapeutic drug vincristine to develop antibody-vincristine conjugates. Vincristine was N-alkylated with a cleavable linker and the resulting linker-payload conjugated to free cysteines of antibodies. We show that trastuzumab-vincristine conjugates display subnanomolar potency in vitro on HER2-positive cells, two orders of magnitude lower than free vincristine and comparable with marketed ADC. In vivo, trastuzumabvincristine conjugates led to remarkable efficacy when compared to two standards of care, with complete tumor regression just nine days after single administration. This highlights the untapped potential of the chemotherapeutic arsenal towards the development of novel ADC.

  • Protocol to generate, purify, and analyze antibody-oligonucleotide conjugates from off-the-shelf antibodies

    Tony Rady, Victor Lehot, Julien Most, Stephane Erb, Sarah Cianférani, Guilhem Chaubet, Nicolas Basse, Alain Wagner
    STAR Protocols, 2024, 5 (4), pp.103329. ⟨10.1016/j.xpro.2024.103329⟩
    Article dans une revue

    <div><p>Protocol to generate, purify, and analyze antibody-oligonucleotide conjugates from offthe-shelf antibodies Antibody-oligonucleotide conjugates (AOCs) are a fast-expanding modality for targeted delivery of therapeutic oligonucleotides to tissues. Here, we present a protocol to generate, purify, and analyze AOCs from off-the-shelf antibodies. We describe steps to conjugate single/doublestranded oligonucleotides bearing amine handles to linkers and, then, to antibodies using wellestablished chemistry. In addition, we provide details regarding the purification techniques and analytical methods suitable for AOC. This protocol can be applied for several purposes where AOC is a modality of interest.</p></div>

  • Supramolecular bioconjugation strategy for antibody-targeted delivery of siRNA

    Manon Ripoll, Héloïse Cahuzac, Igor Dovgan, Sylvain Ursuegui, Patrick Neuberg, Stephane Erb, Sarah Cianférani, Antoine Kichler, Jean-Serge Remy, Alain Wagner
    Bioconjugate Chemistry, 2024, Online ahead of print. ⟨10.1021/acs.bioconjchem.4c00304⟩
    Article dans une revue

    RNA interference is a widely used biological process by which double-stranded RNA induces sequence-specific gene silencing by targeting mRNA for degradation. However, the physicochemical properties of siRNAs make their delivery extremely challenging, thus limiting their bioavailability at the target site. In this context, we developed a versatile and selective siRNA delivery system of a trastuzumab-conjugated nanocarrier. These immunoconjugates consist of the assembly by electrostatic interactions of an oligonucleotide-modified antibody with a cationic micelle for the targeted delivery of siRNA in HER2-overexpressing cancer cells. Results show that, when associated with the corresponding siRNA at the appropriate N/P ratio, our supramolecular assembly was able to efficiently induce luciferase and PLK-1 gene silencing in a cell-selective manner in vitro.

  • Retinoids Molecular Probes by Late‐stage Azide Insertion – Functional Tools to Decrypt Retinoid Metabolism

    Jessica Coulleray, Alexia Kindler, Mohamad Rima, Héloïse Cahuzac, Natacha Rochel, Guilhem Chaubet, Wojciech Krezel, Alain Wagner
    ChemBioChem, 2024, 25 (19), pp.e202300689. ⟨10.1002/cbic.202300689⟩
    Article dans une revue

    Studying the complex and intricate retinoids metabolic pathways by chemical biology approaches requires design and synthesis of biologically functional molecular probes. Only few of such molecular retinoid probes could be found in literature, most of them bearing a molecular structure quite different from natural retinoids. To provide close‐to‐native retinoid probes, we have developed a versatile late‐stage method for the insertion of azide function at the C4 position of several retinoids. This one‐step process opens straightforward access to different retinoid and carotenoid probes from commercially available precursors. We have further demonstrated that the different molecular probes retain ability of the original compound to activate genes’ transcription, despite azide insertion, highlighting biological activities that were further validated in zebrafish in vivo model. The present work paves the way to future studies on vitamin A's metabolism.

  • Drug upgrade: A complete methodology from old drug to new chemical entities using Nematic Protein Organization Technique

    Judith Eschbach, Alain Wagner, Corinne Beahr, Akkiz Bekel, Anne-Sophie Korganow, Angélique Quartier, Jean-Christophe Peter, Pierre Eftekhari
    Drug Development Research, 2024, 85 (1), pp.e22151. ⟨10.1002/ddr.22151⟩
    Article dans une revue

    Drug repurposing is used to propose new therapeutic perspectives. Here, we introduce “Drug Upgrade”, that is, characterizing the mode of action of an old drug to generate new chemical entities and new therapeutics. We proposed a novel methodology covering target identification to pharmacology validation. As an old drug, we chose hydroxychloroquine (HCQ) for its well-documented clinical efficacy in lupus and its side effect, retinal toxicity. Using the Nematic Protein Organization Technique (NPOT®) followed by liquid chromatography-tandem mass spectrometry analyses, we identified myeloperoxidase (MPO) and alpha-crystallin β chain (CRYAB) as primary and secondary targets to HCQ from lupus patients' peripheral blood mononuclear cells (PBMCs) and isolated human retinas. Surface plasmon resonance (SPR) and enzymatic assays confirmed the interaction of HCQ with MPO and CRYAB. We synthesized INS-072 a novel analog of HCQ that increased affinity for MPO and decreased binding to CRYAB compared to HCQ. INS-072 delayed cutaneous eruption significantly compared to HCQ in the murine MRL/lpr model of spontaneous lupus and prevents immune complex vasculitis in mice. In addition, long-term HCQ treatment caused retinal toxicity in mice, unlike INS-072. Our study illustrates a method of drug development, where new applications or improvements can be explored by fully characterizing the drug's mode of action.

  • Site‐Selective Protein Conjugation by a Multicomponent Ugi Reaction

    Ilias Koutsopetras, Valentine Vaur, Rania Benazza, Helene Diemer, Charlotte Sornay, Yağmur Ersoy, Léa Rochet, Carmen Longo, Oscar Hernandez Alba, Stéphane Erb, Alexandre Detappe, Arne Skerra, Alain Wagner, Sarah Cianferani, Guilhem Chaubet
    Chemistry - A European Journal, 2024, 30 (14), pp.e202303242. ⟨10.1002/chem.202303242⟩
    Article dans une revue

    The chemical bioconjugation of proteins has seen tremendous applications in the past decades, with the booming of antibody-drug conjugates and their use in oncology. While genetic engineering has permitted to produce bespoke proteins featuring key (un−)natural amino acid residues poised for site-selective modifications, the conjugation of native proteins is riddled with selectivity issues. Chemoselective strategies are plentiful and enable the precise modification of virtually any residue with a reactive side-chain; site-selective methods are less common and usually most effective on small and medium-sized proteins. In this context, we studied the application of the Ugi multicomponent reaction for the site-selective conjugation of amine and carboxylate groups on proteins, and antibodies in particular. Through an in-depth mechanistic methodology work supported by peptide mapping studies, we managed to develop a set of conditions allowing the highly selective modification of antibodies bearing N-terminal glutamate and aspartate residues. We demonstrated that this strategy did not alter their affinity toward their target antigen and produced an antibody-drug conjugate with subnanomolar potency. Excitingly, we showed that the high site selectivity of our strategy was maintained on other protein formats, especially on anticalins, for which directed mutagenesis helped to highlight the key importance of a single lysine residue.

  • Targeted delivery of immune-stimulating bispecific RNA, inducing apoptosis and anti-tumor immunity in cancer cells

    Tony Rady, Stéphane Erb, Safia Deddouche-Grass, Renaud Morales, Guilhem Chaubet, Sarah Cianferani, Nicolas Basse, Alain Wagner
    iScience, 2024, 27 (3), pp.109068. ⟨10.1016/j.isci.2024.109068⟩
    Article dans une revue

    Double-stranded RNAs (dsRNA)-based strategies appeared as promising therapies to induce an inflammation in the tumor microenvironment. However, currently described systems generally lack active targeting of tissues, and their clinical translation is thus limited to intratumoral injection. Herein, we developed an antibody-siRNA-5′triphosphate conjugate with multiple modes of action, combining cell surface EphA2-specific internalization, leading to a simultaneous gene silencing and activation of the receptor retinoic acid-inducible gene I (RIG-I). Recognition of cytosolic siRNA-5′triphosphate by RIG-I triggers the expression of interferons and pro-inflammatory cytokines, inducing an inflammation of the tumor environment and activating neighboring immune cells. In addition, these RIG-I-specific effects synergized with siRNA-mediated PLK1 silencing to promote cancer cell death by apoptosis. Altogether, such immune-stimulating antibody-RNA conjugate opens a novel modality to overcome some limitations encountered by dsRNA molecules currently in clinical trials.

  • Reinvestigation of the Automated Synthesis of Stoichiometrically Conjugated Antibodies to Access High Molecular Weight Payloads and Multiplexed Conjugation via an In-Solution Trans-Tagging Process

    Victor Lehot, Ondřej Lidický, Julien Most, Stéphane Erb, Igor Dovgan, Artem Osypenko, Oleksandr Koniev, Sergii Kolodych, Lenka Kotrchová, Guilhem Chaubet, Sarah Cianferani, Tomáš Etrych, Alain Wagner
    ACS Omega, 2023, 8 (43), pp.40508-40516. ⟨10.1021/acsomega.3c05206⟩
    Article dans une revue

    Protein conjugates have found applications in a wide variety of fields, ranging from therapeutics to imaging and detection. However, robust control over the parameters of the conjugation process (such as sites and degree of conjugation) remains challenging. Previously, our group introduced Equimolar NAtive Chemical Tagging (ENACT), a method which allows for the monofunctionalization of proteins by combining an iterative low-conversion bioconjugation, an automated process, and a bioorthogonal trans-tagging reaction. However, while the automated ENACT was dimensioned to achieve monoconjugation at the mg scale, in early stage research, because of the rarity and cost of the starting materials, it is often necessary to prepare conjugates at the lower, μg, scale. Here, we introduce modified ENACT protocols, as well as a new ENACT conjugation reagent, which allow for the monofunctionalization of proteins on the micrograms scale, using minimal quantities of payload.

  • Microfluidic Droplet Stabilization via SPAAC Promoted Antibody Conjugation at the Water/Oil Interface

    Robin Dufossez, Marie-Pierre Krafft, Sylvain Ursuegui, Michel Mosser, Safae Mouftakhir, Ketty Pernod, Guilhem Chaubet, Michaël Ryckelynck, Alain Wagner
    ACS Applied Materials & Interfaces, 2023, 15 (38), pp.45498-45505. ⟨10.1021/acsami.3c10655⟩
    Article dans une revue

    Droplet-based microfluidics is leading the development of miniaturized, rapid, and sensitive version of enzyme-linked immunosorbent assays (ELISAs), a central method for protein detection. These assays involve the use of a functionalized surface able to selectively capture the desired analyte. Using the droplet’s oil water interface as a capture surface requires designing custom-perfluorinated fluorosurfactants bearing azide-containing polar groups, which spontaneously react when forming the droplet with strain-alkyne-functionalized antibodies solubilized in the aqueous phase. In this article, we present our research on the influence of the structure of surfactant’s hydrophilic heads on the efficiency of SPAAC functionalization and on the effect of this antibody grafting process on droplet stability. We have shown that while short linkers lead to high grafting efficiency, long linkers lead to high stability, and that an intermediate size is required to balance both parameters. In the described family of surfactants, the optimal structure proved to be a PEG4 linker connecting a polar di-azide head and a per-fluoropolyether tail (Krytox). We also found that grafting an increasing amount of antibody, thus increasing interface coverage, increases droplet stability. It thus appears that such a bi-partite system with a reactive fluoro-surfactant in the oil phase and reactive antibody counterpart in the aqueous phase gives access in situ to novel surfactant construct providing unexplored interface structures and droplet functionality.

  • Targeted Anticancer Agent with Original Mode of Action Prepared by Supramolecular Assembly of Antibody Oligonucleotide Conjugates and Cationic Nanoparticles

    Victor Lehot, Patrick Neuberg, Manon Ripoll, François Daubeuf, Stéphane Erb, Igor Dovgan, Sylvain Ursuegui, Sarah Cianférani, Antoine Kichler, Guilhem Chaubet, Alain Wagner
    Pharmaceutics, 2023, 15 (6), pp.1643. ⟨10.3390/pharmaceutics15061643⟩
    Article dans une revue

    Despite their clinical success, Antibody-Drug Conjugates (ADCs) are still limited to the delivery of a handful of cytotoxic small-molecule payloads. Adaptation of this successful format to the delivery of alternative types of cytotoxic payloads is of high interest in the search for novel anticancer treatments. Herein, we considered that the inherent toxicity of cationic nanoparticles (cNP), which limits their use as oligonucleotide delivery systems, could be turned into an opportunity to access a new family of toxic payloads. We complexed anti-HER2 antibody-oligonucleotide conjugates (AOC) with cytotoxic cationic polydiacetylenic micelles to obtain Antibody-Toxic-Nanoparticles Conjugates (ATNPs) and studied their physicochemical properties, as well as their bioactivity in both in vitro and in vivo HER2 models. After optimising their AOC/cNP ratio, the small (73 nm) HER2-targeting ATNPs were found to selectively kill antigen-positive SKBR-2 cells over antigen-negative MDA-MB-231 cells in serum-containing medium. Further in vivo anti-cancer activity was demonstrated in an SKBR-3 tumour xenograft model in BALB/c mice in which stable 60% tumour regression could be observed just after two injections of 45 pmol of ATNP. These results open interesting prospects in the use of such cationic nanoparticles as payloads for ADC-like strategies.

  • A Novel Family of Acid-Cleavable Linker Based on Cyclic Acetal Motifs for the Production of Antibody-Drug Conjugates with High Potency and Selectivity

    Tony Rady, Lorenzo Turelli, Marc Nothisen, Elisabetta Tobaldi, Stéphane Erb, Fabien Thoreau, Oscar Hernandez-Alba, Sarah Cianferani, François Daubeuf, Alain Wagner, Guilhem Chaubet
    Bioconjugate Chemistry, 2022, ⟨10.1021/acs.bioconjchem.2c00314⟩
    Article dans une revue

    Cleavable linkers have become the subject of intense study in the field of chemical biology, particularly because of their applications in the construction of antibody-drug conjugates (ADC), where they facilitate lysosomal cleavage and liberation of drugs from their carrier protein. Due to lysosomes' acidic nature, acid-labile motifs have attracted much attention, leading to the development of hydrazone and carbonate linkers among several other entities. Continuing our efforts in designing new moieties, we present here a family of cyclic acetals that exhibit excellent plasma stability and acid lability, notably in lysosomes. Incorporated in ADC, they led to potent constructs with picomolar potency in vitro and similar in vivo efficacy as the commercially available ADC Kadcyla in mouse xenograft models.

  • An overview of chemo- and site-selectivity aspects in the chemical conjugation of proteins

    Guilhem Chaubet, Charlotte Sornay, Valentine Vaur, Alain Wagner
    Royal Society Open Science, 2022, 9 (1), ⟨10.1098/rsos.211563⟩
    Article dans une revue

    The bioconjugation of proteins—that is, the creation of a covalent link between a protein and any other molecule—has been studied for decades, partly because of the numerous applications of protein conjugates, but also due to the technical challenge it represents. Indeed, proteins possess inner physico-chemical properties—they are sensitive and polynucleophilic macromolecules—that make them complex substrates in conjugation reactions. This complexity arises from the mild conditions imposed by their sensitivity but also from selectivity issues, viz the precise control of the conjugation site on the protein. After decades of research, strategies and reagents have been developed to address two aspects of this selectivity: chemoselectivity—harnessing the reacting chemical functionality—and site-selectivity—controlling the reacting amino acid residue—most notably thanks to the participation of synthetic chemistry in this effort. This review offers an overview of these chemical bioconjugation strategies, insisting on those employing native proteins as substrates, and shows that the field is active and exciting, especially for synthetic chemists seeking new challenges.

  • Non-specific interactions of antibody-oligonucleotide conjugates with living cells

    Victor Lehot, Isabelle Kuhn, Marc Nothisen, Stéphane Erb, Sergii Kolodych, Sarah Cianférani, Guilhem Chaubet, Alain Wagner
    Scientific Reports, 2021, 11 (1), ⟨10.1038/s41598-021-85352-w⟩
    Article dans une revue

    Antibody-Oligonucleotide Conjugates (AOCs) represent an emerging class of functionalized antibodies that have already been used in a wide variety of applications. While the impact of dye and drug conjugation on antibodies’ ability to bind their target has been extensively studied, little is known about the effect caused by the conjugation of hydrophilic and charged payloads such as oligonucleotides on the functions of an antibody. Previous observations of non-specific interactions of nucleic acids with untargeted cells prompted us to further investigate their impact on AOC binding abilities and cell selectivity. We synthesized a series of single- and double-stranded AOCs, as well as a human serum albumin-oligonucleotide conjugate, and studied their interactions with both targeted and non-targeted living cells using a time-resolved analysis of ligand binding assay. Our results indicate that conjugation of single strand oligonucleotides to proteins induce consistent non-specific interactions with cell surfaces while double strand oligonucleotides have little or no effect, depending on the preparation method.

  • Bicyclo[6.1.0]nonyne carboxylic acid for the production of stable molecular probes

    Tony Rady, Michel Mosser, Marc Nothisen, Stephane Erb, Igor Dovgan, Sarah Cianférani, Alain Wagner, Guilhem Chaubet
    RSC Advances, 2021, 11, pp.36777 - 36780. ⟨10.1039/d1ra07905k⟩
    Article dans une revue

    Bicyclo[6.1.0]non-4-yn-9-ylmethanol (BCN alcohol) is the most prominent strained-alkyne scaffold in chemical biology. Described herein is the synthesis of an oxidized analogue-BCN acidwhose facile functionalization via amide bond formation yields more stable derivatives than the classically encountered carbamates.

  • Plasma induced acceleration and selectivity in strain-promoted azide–alkyne cycloadditions

    David Warther, Enes Dursun, Marion Recher, Sylvain Ursuegui, Michel Mosser, Joanna Sobska, Wojciech Krezel, Guilhem Chaubet, Alain Wagner
    Organic & Biomolecular Chemistry, 2021, 19 (23), pp.5063-5067. ⟨10.1039/D1OB00529D⟩
    Article dans une revue

    We report the unexpected acceleration of strain-promoted azide–alkyne cycloaddition in human plasma compared to classical solvent systems. Besides fast kinetics, human plasma also allows for discrimination between two azides in competition reaction.

  • Manniindole, an indole derivative from the roots of Anonidium mannii and combined antischistosomal and enzymatic activities

    Josette Linda Toussi Matchi, Diderot Tchamo Noungoue, Isabelle Kuhn, Jérôme Boissier, Jean Claude Tchouankeu, Marc Nothisen, Guilhem Chaubet, Delphine Garnier, Sylvain Ursuegui, Silvère Augustin Ngouela, Alain Wagner
    Natural Product Research, 2021, 35 (24), pp.5665-5673. ⟨10.1080/14786419.2020.1824227⟩
    Article dans une revue

    A new alkaloid, manniindole 1, together with four known compounds: aristolactam AII 2, aristolactam BII 3, piperolactam D 4 and polycarpol 5 were isolated from the crude extract EtOHH2O (8:2) of the roots of Anonidium mannii by chromatographic separation. The structure elucidation was performed on the basis of a spectroscopic analysis (IR, HRESI MS, 1D and 2D NMR) as well as a comparison of their spectral data with those reported in the literature. For the first time, the crude extract and those isolated compounds were evaluated for their antischistosomal activity against Schistosoma mansoni and for cytotoxicity activity against Huh7 and A549 cells. Furthermore, they were also tested in vitro on the recent characterized Schistosoma mansoni NADþ catabolizing enzyme (SmNACE) for their impact on this enzyme which is localized on the outer surface of the adult parasite. Compound 2 displayed quite good worm killing capability, while 4 showed significant inhibition of SmNACE

  • Antischistosomal Evaluation of Stem Bark's Extract and Chemical Constituents from Anonidium mannii against Schistosoma mansoni

    Josette Linda Toussi Matchi, Diderot Tchamo Noungoue, Guilhem Chaubet, Jérôme Boissier, Isabelle Kuhn, Jean-Claude Tchouankeu, Marc Nothisen, Sylvain Ursuegui, Silvère Augustin Ngouela, Alain Wagner
    Pharmacognosy Magazine, 2021, 17 (76), pp.752-758. ⟨10.4103/pm.pm_29_21⟩
    Article dans une revue

    Context: Anonidium mannii (Annonaceae) has been traditionally used in Africa to treat stomach aches, schistosomiasis, and many other illnesses. However, few phytochemical study and no investigation on schistosomiasis have been conducted on this species. This neglected tropical disease, caused by a worm, comes second after malaria as the most devastating parasitical infection. Aim: The goal of this study was to evaluate the anti-Schistosoma mansoni activity of fractions and constituents from A. mannii's stem bark and also to search efficient inhibitors of a recently discovered ectoenzyme of S. mansoni (S. mansoni nicotinamide adenine dinucleotide + catabolizing enzyme [SmNACE]). Materials and Methods: The powdered stem bark of A. mannii was extracted with ethanol/distilled water (80:20). The extract was then subjected to a partial bioguided separation by chromatography means. The structures of compounds were elucidated using modern spectroscopic techniques. Furthermore, isolated and semisynthetic compounds were evaluated for their antischistosomal and cytotoxic activities. Results: Chemical investigation led to the isolation and identification of eight compounds, in the majority, obtained for the first time from this genus. In addition, acetylation reactions were carried out to afford a new semisynthetic derivative. Preliminary biological screening of the extracts and compounds showed very good activities from antiparasitic and enzymatic tests and also very good percentage of cell viability evaluation. Conclusion: Like praziquantel drug, gallic acid exhibited full anthelmintic activity at concentration of 100 µM. On the other hand, piperolactam D showed important inhibition on SmNACE (IC 50 10 µM). Thus, standardization of bioactive fraction can help in improving traditional medicine. The optimization of those two compounds will enhance their selectivity/ effectiveness and could be used as seed for the development of new remedies against schistosomiasis. Further, the study will be focus on other pathogens species of Schistosoma genus.

  • Ethynylation of Cysteines from Peptides to Proteins in Living Cells

    Romain Tessier, Raj Kumar Nandi, Brendan G Dwyer, Daniel Abegg, Charlotte Sornay, Javier Ceballos, Stéphane Erb, Sarah Cianferani, Alain Wagner, Guilhem Chaubet, Alexander Adibekian, Jerome Waser
    Angewandte Chemie, 2020, 132 (27), pp.11054-11063. ⟨10.1002/ange.202002626⟩
    Article dans une revue

    Efficient methods to introduce bioorthogonal groups, such as terminal alkynes, into biomolecules are important tools for chemical biology. State-of-the-art approaches are based on the introduction of a linker between the targeted amino acid and the alkyne, and still present limitations of either reactivity, selectivity or adduct stability. Herein, we present an ethynylation method of cysteine residues based on the use of ethynylbenziodoxolone (EBX) reagents. In contrast to other approaches, the acetylene group is directly introduced onto the thiol group of cysteine and can be used in one-pot in a copper-catalyzed alkyne-azide cycloaddition (CuAAC) for further functionalization. Labeling proceeded with reaction rates comparable or higher than the most often used iodoacetamide on peptides or maleimide on the antibody trastuzumab. Under optimized conditions, high cysteine selectivity was observed. The reagents were also used in living cells for cysteine proteomic profiling and displayed an improved coverage of the cysteinome compared to previously reported iodoacetamide or hypervalent iodine-reagent based probes. Fine-tuning of the EBX reagents allowed optimization of their reactivity and physical properties for the desired application.

  • On the use of DNA as a linker in antibody-drug conjugates: synthesis, stability and in vitro potency

    Igor Dovgan, Anthony Ehkirch, Victor Lehot, Isabelle Kuhn, Oleksandr Koniev, Sergii Kolodych, Alexandre Hentz, Manon Ripoll, Sylvain Ursuegui, Marc Nothisen, Sarah Cianférani, Alain Wagner
    Scientific Reports, 2020, 10 (1), ⟨10.1038/s41598-020-64518-y⟩
    Article dans une revue

    Here we present the synthesis and evaluation of antibody-drug conjugates (ADCs), for which antibody and drug are non-covalently connected using complementary DNA linkers. These ADCs are composed of trastuzumab, an antibody targeting HER2 receptors overexpressed on breast cancer cells, and monomethyl auristatin E (MMAE) as a drug payload. In this new ADC format, trastuzumab conjugated to a 37-mer oligonucleotide (ON) was prepared and hybridized with its complementary ON modified at 5-end with MMAE (cON-MMAE) in order to obtain trastuzumab-DNA-MMAE. As an advantage, the cON-MMAE was completely soluble in water, which decreases overall hydrophobicity of toxic payload, an important characteristic of ADCs. The stability in the human plasma of these non-engineered ON-based linkers was investigated and showed a satisfactory half-life of 5.8 days for the trastuzumab-DNA format. Finally, we investigated the in vitro cytotoxicity profile of both the DNA-linked ADC and the ON-drug conjugates and compared them with classical covalently linked ADC. Interestingly, we found increased cytotoxicity for MMAE compared to cON-MMAE and an EC50 in the nanomolar range for trastuzumab-DNA-MMAE on HER2-positive cells. Although this proved to be less potent than classically linked ADC with picomolar range EC50, the difference in cytotoxicity between naked payload and conjugated payload was significant when an ON linker was used. We also observed an interesting increase in cytotoxicity of trastuzumab-DNA-MMAE on HER2-negative cells. This was attributed to enhanced non-specific interaction triggered by the DNA strand as it could be confirmed using ligand tracer assay.

  • Investigating Ugi/Passerini Multicomponent Reactions for the Site‐Selective Conjugation of Native Trastuzumab

    Charlotte Sornay, Steve Hessmann, Stéphane Erb, Igor Dovgan, Anthony Ehkirch, Thomas Botzanowski, S. Cianferani, Alain Wagner, G. Chaubet
    Chemistry - A European Journal, 2020, 26 (61), pp.13797-13805. ⟨10.1002/chem.202002432⟩
    Article dans une revue

    Site-selective modification of proteins has been the object of intense studies over the past decades, especially in the therapeutic field. Prominent results have been obtained with recombinant proteins, for which site-specific conjugation is made possible by the incorporation of particular amino acid residues or peptide sequences. In parallel, methods for the site-selective and site-specific conjugation of native and natural proteins are starting to thrive, allowing the controlled functionalization of various types of amino acid residues. Pursuing the efforts in this field, we planned to develop a new type of site-selective method, aiming at the simultaneous conjugation of two amino acid residues. We reasoned that this should give higher chances of developing a site-selective strategy compared to the large majority of existing methods that solely target a single residue. We opted for the Ugi four-center three-component reaction to implement this idea, with the aim of conjugating the side-chain amine and carboxylate groups of two neighbouring lysine and aspartate/glutamate. Herein, we show that this strategy can give access to valuable antibody conjugates bearing several different payloads, and limits the potential conjugation sites to only six on the model antibody trastuzumab. Posttranslational modifications of proteins is Nature's way of generating a rich and diverse proteome from a more limited genetic coding capability. First occurrences of intentional, man-made-artificial-proteins modifications using a defined chemical-thus excluding the food-related Maillard reaction for example-could be dated back to the use of formaldehyde in the tanning industry or for the production of toxoids, 1,2 which evolved later on to immunization studies using chemically-modified bovine serum albumin in the 1900s and eventually led to Landsteiner's synthetic haptenes studies. 3,4 The field of protein modification has since largely benefited from the understanding of proteins' and amino acids' structures coupled to the parallel appearance of more efficient and precise analytical tools. This finally resulted in the development of bioconjugation reagents with excellent chemoselectivity towards various amino acids' side chains groups (i.e. residue-selectivity) that translated into major applications, notably in the pharmaceutical field with the generation of protein-fluorophore adducts for trafficking studies, or the polyethyleneglycol chains functionalization (PEGylation) of proteins to give less-immunogenic and more plasma-stable conjugates. 5,6 However, site selectivity quickly emerged as the main limitation of chemoselective strategies, due to the presence of multiple copies of each type of amino acid residue at the surface of proteins. Statistic conjugation of surface-accessible lysine residues with amine-selective reagents typically results in highly heterogeneous mixtures, containing up to millions of different adducts when large proteins such as antibodies are utilised. 7,8 Each of these adducts possessing distinct physicochemical properties, such chemoselective conjugation necessarily leads to mixtures with different in-vivo pharmacokinetic properties along with virtually no reproducibility in batch-to-batch production. 9,10 Regioselective (i.e., site-specific) methods were thus developed and are currently dominated by the use of recombinant proteins, incorporating exogenous amino acid residues-natural or unnatural-or peptide sequences that can be specifically targeted by a tailored reagent or strategy. 11-13 In parallel, site-selective chemical strategies for the conjugation of native and natural proteins have also flourished over the past few years, giving rise to methods targeting various types of amino acids-e.g. lysine, cysteine, tryptophan, tyrosine-that proved to be effective on proteins of all sorts of sizes, including antibodies. 14-28 With the aim of pursuing the efforts in this field, we could not help but notice that the vast majority of previously reported strategies for the site-selective conjugation of native proteins were focused on the modification of a unique residue. We hypothesized that targeting two different amino acid side chains simultaneously would lower the enormous subset of possibilities given by single-residue bioconjugation techniques, thus increasing our chances of developing a site-selective method by minimising the number

  • Automated linkage of proteins and payloads producing monodisperse conjugates

    Igor Dovgan, Alexandre Hentz, Oleksandr Koniev, Anthony Ehkirch, Steve Hessmann, Sylvain Ursuegui, Sébastien Delacroix, Margaux Riomet, Frédéric Taran, Sarah Cianférani, Sergii Kolodych, Alain Wagner
    Chemical Science, 2020, 11 (5), pp.1210-1215. ⟨10.1039/c9sc05468e⟩
    Article dans une revue

    Controlled protein functionalization holds great promise for a wide variety of applications. However, despite intensive research, the stoichiometry of the functionalization reaction remains difficult to control due to the inherent stochasticity of the conjugation process. Classical approaches that exploit peculiar structural features of specific protein substrates, or introduce reactive handles via mutagenesis, are by essence limited in scope or require substantial protein reengineering. We herein present equimolar native chemical tagging (ENACT), which precisely controls the stoichiometry of inherently random conjugation reactions by combining iterative low-conversion chemical modification, process automation, and bioorthogonal trans-tagging. We discuss the broad applicability of this conjugation process to a variety of protein substrates and payloads.

  • Antibody–Oligonucleotide Conjugates as Therapeutic, Imaging, and Detection Agents

    Igor Dovgan, Oleksandr Koniev, Sergii Kolodych, Alain Wagner
    Bioconjugate Chemistry, 2019, 30 (10), pp.2483-2501. ⟨10.1021/acs.bioconjchem.9b00306⟩
    Article dans une revue

    Antibody–oligonucleotide conjugates (AOCs) are a novel class of synthetic chimeric biomolecules that has been continually gaining traction in different fields of modern biotechnology. This is mainly due to the unique combination of the properties of their two constituents, exceptional targeting abilities and antibody biodistribution profiles, in addition to an extensive scope of oligonucleotide functional and structural roles. Combining these two classes of biomolecules in one chimeric construct has therefore become an important milestone in the development of numerous biotechnological applications, including imaging (DNA-PAINT), detection (PLA, PEA), and therapeutics (targeted siRNA/antisense delivery). Numerous synthetic approaches have been developed to access AOCs ranging from stochastic chemical bioconjugation to site-specific conjugation with reactive handles, introduced into antibody sequences through protein engineering. This Review gives a general overview of the current status of AOC applications with a specific emphasis on the synthetic methods used for their preparation. The reported synthetic techniques are discussed in terms of their practical aspects and limitations. The importance of the development of novel methods for the facile generation of AOCs possessing a defined constitution is highlighted as a priority in AOC research to ensure the advance of their new applications.

  • Design and evaluation of ionizable peptide amphiphiles for siRNA delivery

    Patrick Neuberg, Alain Wagner, Jean-Serge Remy, Antoine Kichler
    International Journal of Pharmaceutics, 2019, 566, pp.141-148. ⟨10.1016/j.ijpharm.2019.05.052⟩
    Article dans une revue

    Small interfering RNAs (siRNAs) can down-regulate the expression of a target mRNA molecule in a sequence-specific manner, making them an attractive new class of drugs with broad potential for the treatment of diverse human diseases. Here, we report the synthesis of a series of cationic amphiphiles which were obtained by the coupling of amino acids and dipeptides onto a lipidic double chain. The new amphiphiles presenting a peptidic motif on a short hydrophilic spacer group were evaluated for selective gene silencing through RNA interference. Our results show that tryptophan residues boost siRNA delivery in an unexpected manner. The silencing experiments performed with very low concentrations of siRNA showed that the best formulations could induce significant death of tumor cells after silencing of polo-like kinase 1 which is implicated in cell cycle progression. In addition, these Trp containing peptide amphiphiles were highly efficient siRNA delivery vectors even in presence of competing serum proteins.

  • 2nd PSL Chemical Biology Symposium (2019): At the Crossroads of Chemistry and Biology

    Marco Lucchino, Anne Billet, Antoine Versini, Harikrishna Bavireddi, Bhanu-Das Dasari, Sylvain Debieu, Ludovic Colombeau, Tatiana Cañeque, Alain Wagner, Geraldine Masson, Frédéric Taran, Philippe Karoyan, Muriel Delepierre, Christine Gaillet, Anne Houdusse, Sébastien Britton, Frederic Schmidt, Jean-Claude Florent, Philippe Belmont, David Monchaud, Janine Cossy, Christophe Thomas, Arnaud Gautier, Ludger Johannes, Raphaël Rodriguez
    ChemBioChem, 2019, 20 (7), pp.968-973. ⟨10.1002/cbic.201900092⟩
    Article dans une revue

    Chemical Biology is the science of designing chemical tools to dissect and manipulate biology at different scales. It provides the fertile ground from which to address important problems of our society, such as human health and environment.

  • Sydnone-based turn-on fluorogenic probes for no-wash protein labeling and in-cell imaging

    Lucie Plougastel, Manas R Pattanayak, Margaux Riomet, Sarah Bregant, Antoine Sallustrau, Marc Nothisen, Alain Wagner, Davide Audisio, Frédéric Taran
    Chemical Communications, 2019, 55 (31), pp.4582-4585. ⟨10.1039/c9cc01458f⟩
    Article dans une revue

    We report the synthesis and use of sydnone-based profluorophores as tools for imaging applications. These new probes display exquisite reactivity for strain promoted cycloaddition reactions with cycloalkynes allowing fast, efficient and selective labeling in biological media. Styryl-pyridinium sydnone probes were found particularly interesting for click reactions to proceed selectively inside cells.

  • Synthesis and Kinetic evaluation of an azido analogue of methylerythritol phosphate: a Novel Inhibitor of E. coli YgbP/IspD

    Zoljargal Baatarkhuu, Philippe Chaignon, Franck Borel, Jean-Luc Ferrer, Alain Wagner, Myriam Seemann
    Scientific Reports, 2018, 8 (1), pp.17892. ⟨10.1038/s41598-018-35586-y⟩
    Article dans une revue

    As multidrug resistant pathogenic microorganisms are on the horizon, it is crucial to develop continuously novel medicines in order to overcome the emerging resistance. The methylerythritol phosphate pathway (MEP) is an ideal target for antimicrobial development as it is absent in humans but present in most bacteria and in the parasite Plasmodium falciparum. Here, we report the synthesis and the kinetic parameters of a novel potent inhibitor (MEPN3) of Escherichia coli YgbP/IspD, the third enzyme of the MEP pathway. MEPN3 inhibits E. coli YgbP/IspD in mixed type mode regarding both substrates. Interestingly, MEPN3 shows the highest inhibitory activity when compared to known inhibitors of E. coli YgbP/IspD. The mechanism of this enzyme was also studied by steady state kinetic analysis and was found to be sequential where substrates add to the enzyme in sequential manner.

  • Expedient synthesis of trifunctional oligoethyleneglycol-amine linkers and their use in the preparation of PEG-based branched platforms

    Sylvain Ursuegui, Jérémy Schneider, Claire Imbs, Florian Lauvoisard, Marta Dudek, Michel Mosser, Alain Wagner
    Organic and Biomolecular Chemistry, 2018, 16 (44), pp.8579-8584. ⟨10.1039/C8OB02097C⟩
    Article dans une revue

    We designed a convergent synthesis pathway that provides access to trifunctional oligoethyleneglycol-amine (OEG-amine) linkers. By applying the reductive coupling of a primary azide to bifunctional OEG-azide precursors, the corresponding symmetrical dialkylamine bearing two homo-functional end chain groups and a central nitrogen was obtained. These building blocks bear minimal structural perturbation compared to the native OEG backbone which makes them attractive for biomedical applications. The NMR investigations of the mechanism process reveal the formation of nitrile and imine intermediates which can react with the reduced free amine form. Additionally, these trifunctional OEG-amine linkers were employed in a coupling reaction to afford branched multifunctional PEG dendrons which are molecularly defined. These discrete PEG-based dendrons (n = 16, 18 and 36) could be useful for numerous applications where multivalency is required.

  • Co-delivery of anti-PLK-1 siRNA and camptothecin by nanometric polydiacetylenic micelles results in a synergistic cell killing

    Manon Ripoll, Marie Pierdant, Patrick Neuberg, Dominique Bagnard, Alain Wagner, Antoine Kichler, Jean-Serge Remy
    RSC Advances, 2018, 8 (37), pp.20758-20763. ⟨10.1039/C8RA03375G⟩
    Article dans une revue

    Recently, it has been shown that the efficiency of antitumoral drugs can be enhanced when combined with therapeutic siRNAs. In the present study, an original platform based on polydiacetylenic micelles containing a cationic head group able to efficiently deliver a small interfering RNA (siRNA) targeting the PLK-1 gene while offering a hydrophobic environment for encapsulation of lipophilic drugs such as camptothecin is developed. We demonstrate that the co-delivery of these two agents with our micellar system results in a synergistic tumor cell killing of cervical and breast cancer cell lines in vitro. The combined drugs are active in a subcutaneous in vivo cancer model. Altogether, the results show that our nanometric micellar delivery system can be used for the development of new drug–siRNA combo-therapies.

  • Inhibition of dengue virus infection by mannoside glycolipid conjugates

    Evelyne Schaeffer, Vincent Flacher, Patrick Neuberg, Astrid Hoste, Adrien Brulefert, Jean-Daniel Fauny, Alain Wagner, Christopher Mueller
    Antiviral Research, 2018, 154, pp.116-123. ⟨10.1016/j.antiviral.2018.04.005⟩
    Article dans une revue

    Dengue virus (DENV), a mosquito-borne flavivirus, causes severe and potentially fatal symptoms in millions of infected individuals each year. Although dengue fever represents a major global public health problem, the vaccines or antiviral drugs proposed so far have not shown sufficient efficacy and safety, calling for new antiviral developments. Here we have shown that a mannoside glycolipid conjugate (MGC) bearing a trimannose head with a saturated lipid chain inhibited DENV productive infection. It showed remarkable cell promiscuity, being active in human skin dendritic cells, hepatoma cell lines and Vero cells, and was active against all four DENV serotypes, with an IC 50 in the low micromolar range. Time-of-addition experiments and structure-activity analyses revealed the importance of the lipid chain to interfere with an early viral infection step. This, together with a correlation between antiviral activity and membrane polarization by the lipid moiety indicated that the in-hibitor functions by blocking viral envelope fusion with the endosome membrane. These finding establish MGCs as a novel class of antivirals against the DENV.

  • Arginine-selective bioconjugation with 4-azidophenyl glyoxal: application to the single and dual functionalisation of native antibodies

    Igor Dovgan, Stéphane Erb, Steve Hessmann, Sylvain Ursuegui, Chloé Michel, Christian Muller, Guilhem Chaubet, Sarah Cianférani, Alain Wagner
    Organic & Biomolecular Chemistry, 2018, 16 (8), pp.1305-1311. ⟨10.1039/c7ob02844j⟩
    Article dans une revue

    Here, we introduce 4-azidophenyl glyoxal (APG) as an efficient plug-and-play reagent for the selective functionalisation of arginine residues in native antibodies. The selective reaction between APG and arginines’ guanidine groups allowed a facile introduction of azide groups on the monoclonal antibody trastuzumab (plug stage). These pre-functionalised antibody–azide conjugates were then derivatised during the “play stage” via a biorthogonal cycloaddition reaction with different strained alkynes. This afforded antibody-fluorophore and antibody–oligonucleotide conjugates, all showing preserved antigen selectivity and high stability in human plasma. Due to a lower content of arginines compared to lysines in native antibodies, this approach is thus attractive for the preparation of more homogeneous conjugates. This method proved to be orthogonal to classical lysine-based conjugation and allowed straightforward generation of dual-payload antibody.

  • In situ targeted activation of an anticancer agent using ultrasound-triggered release of composite droplets

    Sergii Kolodych, Chloé Michel, Sébastien Delacroix, Oleksandr Koniev, Anthony Ehkirch, Jitka Eberova, Sarah Cianferani, Wojciech Krezel, Pauline Poinot, Christian Muller, Alain Wagner, Marine Bezagu, Jonathan A. Clarhaut, Brigitte Renoux, Fabrice Monti, Mickaël Tanter, Patrick Tabeling, Janine Cossy, Olivier Couture, Sébastien Papot, Stellios Arseniyadis
    European Journal of Medicinal Chemistry, 2017, 142, pp.2-7. ⟨10.1016/j.ejmech.2017.03.057⟩
    Article dans une revue

  • Bioorthogonal Click and Release Reaction of Iminosydnones with Cycloalkynes

    Sabrina Bernard, Davide Audisio, Margaux Riomet, Sarah Bregant, Antoine Sallustrau, Lucie Plougastel, Elodie Decuypere, Sandra Gabillet, Ramar Arun Kumar, Jijy Elyian, Minh Nguyet Trinh, Oleksandr Koniev, Alain Wagner, Sergii Kolodych, Frédéric Taran
    Angewandte Chemie International Edition, 2017, 56 (49), pp.15612-15616. ⟨10.1002/anie.201708790⟩
    Article dans une revue

    Abstract We report the discovery of a new bioorthogonal click‐and‐release reaction involving iminosydnones and strained alkynes. This transformation leads to two products resulting from the ligation and fragmentation of iminosydnones under physiological conditions. Optimized iminosydnones were successfully used to design innovative cleavable linkers for protein modification, thus opening up new areas in the fields of drug release and target‐fishing applications. This click‐and‐release technology offers the possibility of exchanging tags on proteins for functionalized cyclooctynes under mild and bioorthogonal conditions.

  • Structural investigation of cyclo-dioxo maleimide cross-linkers for acid and serum stability

    Elisabetta Tobaldi, Igor Dovgan, Michel Mosser, Jean-Michel Becht, Alain Wagner
    Organic & Biomolecular Chemistry, 2017, 15 (44), pp.9305-9310. ⟨10.1039/c7ob01757j⟩
    Article dans une revue

    The biochemical characteristics of hetero-bifunctional cross-linkers used in bioconjugates are of essential importance to the desired features of the final adduct (i.e. antibody-drug conjugates). These include stability in biological media, chemical and biological reactivities, cleavability under defined conditions, and solubility. In our previous work, we introduced a new amino-to-thiol linker, maleimidomethyl dioxane (MD), as an alternative to classical maleimide conjugation, with increased hydrophilicity and serum stability due to succinimidyl ring-opening. In this work, we investigate the generality of linkers containing a dioxoring with regard to their ability to self-hydrolyze and their surprising stability at a low pH. We synthesized four FRET probes which allowed us to address the stability of the dioxo-ring and to study the maleimide ring-opening and the thiol-exchange processes by means of detecting and measuring the generation of fluorescence. It was found that the ring expansion (from a 5- to a 6-membered ring) improved the stability of the probes in aqueous media, and the increase of the chain length between the dioxo-ring and the succinimide ring (from methylene to ethylene) decreased the rate of succinimidyl ring-opening.

  • An in vivo strategy to counteract post-administration anticoagulant activity of azido-Warfarin

    Sylvain Ursuegui, Marion Recher, Wojciech Krężel, Alain Wagner
    Nature Communications, 2017, 8, pp.15242. ⟨10.1038/ncomms15242⟩
    Article dans une revue

    Drugs, usually long acting and metabolically stable molecules, might be the source of adverse effects triggered by complex drug interactions, anaphylaxis and drug-induced coagulopathy. To circumvent this growing drug safety issue, we herein investigate the opportunity offered by bio-orthogonal chemistry for in vivo drug neutralization. We design a small-molecule anticoagulant drug (Warfarin) containing an azide group that acts as a safety pin. It allows drug deactivation and restoration of physiological coagulation via in vivo click reaction with a suitable cyclooctyne-based neutralizing agent. In this strategy, the new molecule formed by reaction of the drug and the antidote is deprived of biological activity and prone to fast renal clearance. This 'Click &Clear' approach lays ground for new strategies in designing drugs with switchable biophysical properties.

  • pH-Responsive Nanometric Polydiacetylenic Micelles Allow for Efficient Intracellular siRNA Delivery

    Manon Ripoll, Patrick Neuberg, Antoine Kichler, Nassera Tounsi, Alain Wagner, Jean-Serge Remy
    ACS Applied Materials & Interfaces, 2016, 8 (45), pp.30665-30670. ⟨10.1021/acsami.6b09365⟩
    Article dans une revue

    A novel generation of pH-responsive photopolymerized diacetylenic amphiphile (PDA) micelles with a diameter of 10 nm was designed and optimized for the intracellular delivery of siRNAs. Dialysis and photopolymerization of the micelles allowed a strong reduction of the cytotoxicity of the nanovector, while the hydrophilic histidine headgroup permitted enhancing the siRNA delivery potential by improving the endosomal escape via imidazole protonation. These PDA-micellar systems were fully characterized by DLS, TEM, and DOSY-NMR experiments. The resulting bioactive complexes of PDA-micelles with siRNA were shown to have an optimal size below 100 nm.

  • Ultrafast Click Chemistry with Fluorosydnones

    Hui Liu, Davide Audisio, Lucie Plougastel, Elodie Decuypere, David‐alexandre Buisson, Oleksandr Koniev, Sergii Kolodych, Alain Wagner, Mourad Elhabiri, Anna Krzyczmonik, Sarita Forsback, Olof Solin, Véronique Gouverneur, Frédéric Taran
    Angewandte Chemie International Edition, 2016, 55 (39), pp.12073-12077. ⟨10.1002/anie.201606495⟩
    Article dans une revue

    Abstract We report the synthesis and reactivity of 4‐fluorosydnones, a unique class of mesoionic dipoles displaying exquisite reactivity towards both copper‐catalyzed and strain‐promoted cycloaddition reactions with alkynes. Synthetic access to these new mesoionic compounds was granted by electrophilic fluorination of σ‐sydnone Pd II precursors in the presence of Selectfluor. Their reactions with terminal and cyclic alkynes were found to proceed very rapidly and selectively, affording 5‐fluoro‐1,4‐pyrazoles with bimolecular rate constants up to 10 4 m −1 s −1 , surpassing those documented in the literature with cycloalkynes. Kinetic studies were carried out to unravel the mechanism of the reaction, and the value of 4‐fluorosydnones was further highlighted by successful radiolabeling with [ 18 F]Selectfluor.

  • 2-(Maleimidomethyl)-1,3-Dioxanes (MD): a Serum-Stable Self-hydrolysable Hydrophilic Alternative to Classical Maleimide Conjugation

    Igor Dovgan, Sergii Kolodych, Oleksandr Koniev, Alain Wagner
    Scientific Reports, 2016, 6 (1), pp.30835. ⟨10.1038/srep30835⟩
    Article dans une revue

    <div><p>The vast majority of antibody-drug conjugates (ADC) are prepared through amine-to-thiol conjugation. To date, N-Succinimidyl-4-(maleimidomethyl) cyclohexanecarboxylate (SMCC) has been one of the most frequently applied reagents for the preparation of ADC and other functional conjugates. However, SMCC-based conjugates suffer from limited stability in blood circulation and from a hydrophobic character of the linker, which may give rise to major pharmacokinetic implications. To address this issue, we have developed a heterobifunctional analogue of a SMCC reagent, i.e., sodium 4-(maleimidomethyl)-1,3-dioxane-5-carbonyl)oxy)-2,3,5,6-tetrafluorobenzenesulfonate (MDTF) for amine-to-thiol conjugation. By replacing the cyclohexyl ring in the SMCC structure with the 1,3-dioxane, we increased the hydrophilicity of the linker. A FRET probe based on MD linker was prepared and showed superior stability compared to the MCC linker in human plasma, as well as in a variety of aqueous buffers. A detailed investigation demonstrated an accelerated succinimide ring opening for MD linker, resulting in stabilized conjugates. Finally, the MDTF reagent was applied for the preparation of serum stable antibody-dye conjugate.</p></div>

  • Palladium‐Catalyzed Chemoselective and Biocompatible Functionalization of Cysteine‐Containing Molecules at Room Temperature

    Riyadh Ahmed Atto Al-Shuaeeb, Sergii Kolodych, Oleksandr Koniev, Sébastien Delacroix, Stéphane Erb, Stéphanie Nicolaÿ, Jean‐christophe Cintrat, Jean‐daniel Brion, Sarah Cianférani, Mouâd Alami, Alain Wagner, Samir Messaoudi
    Chemistry - A European Journal, 2016, 22 (32), pp.11365-11370. ⟨10.1002/chem.201602277⟩
    Article dans une revue

    Abstract The third generation of aminobiphenyl palladacycle pre‐catalyst “G3‐Xantphos” enables functionalization of peptides containing cysteine in high yields. The conjugation (bioconjugation) occurs chemoselectively at room temperature under biocompatible conditions. Extension of the method to protein functionalization allows selective bioconjugation of the trastuzumab antibody.

  • From solution to in-cell study of the chemical reactivity of acid sensitive functional groups: a rational approach towards improved cleavable linkers for biospecific endosomal release

    Sylvain A. Jacques, Geoffray Leriche, Michel Mosser, Marc Nothisen, Christian Muller, Jean-Serge Remy, Alain Wagner
    Organic & Biomolecular Chemistry, 2016, 14 (21), pp.4794-4803. ⟨10.1039/C6OB00846A⟩
    Article dans une revue

    pH-Sensitive linkers designed to undergo selective hydrolysis at acidic pH compared to physiological pH can be used for the selective release of therapeutics at their site of action. In this paper, the hydrolytic cleavage of a wide variety of molecular structures that have been reported for their use in pH-sensitive delivery systems was examined. A wide variety of hydrolytic stability profiles were found among the panel of tested chemical functionalities. Even within a structural family, a slight modification of the substitution pattern has an unsuspected outcome on the hydrolysis stability. This work led us to establish a first classification of these groups based on their reactivities at pH 5.5 and their relative hydrolysis at pH 5.5 vs. pH 7.4. From this classification, four representative chemical functions were selected and studied in-vitro. The results revealed that only the most reactive functions underwent significant lysosomal cleavage, according to flow cytometry measurements. These last results question the acid-based mechanism of action of known drug release systems and advocate for the importance of an in-depth structure-reactivity study, using a tailored methodology, for the rational design and development of bio-responsive linkers.

  • Copper-free click chemistry for microdroplet's W/O interface engineering

    Sylvain Ursuegui, Michel Mosser, Alain Wagner
    RSC Advances, 2016, A Decade of Progress in Click Reactions Based on CuAAC, 6 (97), pp.94942-94948. ⟨10.1039/C6RA20385J⟩
    Article dans une revue

    In droplet-based microfluidic, fluorosurfactants are essential to ensure the stability of the emulsion. Beyond this primary role, fluorosurfactants can be engineered to provide droplet inner surface specific interaction characteristics with analyte present in droplet content. Despite the high potency of such capture system in terms of micro-compartmentalisation and surface/analyte ratio, only few studies have reported the use of the water/fluorinated oil interphase to immobilize target molecules. The difficult synthesis of the required functionalized fluorosurfactants needed for each application may account for this relative desertion. To make microdroplet capture approaches more straightforward, we have investigated a ready-to-use click chemistry-based approach that enables intra-droplet chemical modification. This strategy, which avoids tedious synthesis of complex fluorosurfactant, opens access to a wide variety of functional heads via copper-free click chemistry using a pre-functionalized fluorosurfactant which can be easily obtained in large scale. To demonstrate the efficiency of the click chemistry-based microdroplet surface functionalization, we have synthesized an azide fluorosurfactant capable of stabilizing microdroplets and performed a series of intra-droplet surface functionalizations by introducing fluorescent-labeled cycloalkyne derivatives in the aqueous phase. By doing so, we were able to demonstrate via polarization fluorescence that molecules from the aqueous phase could be efficiently captured at the inner droplet surface. Furthermore, we also showed that the density of azide functions at the inner surface could be adjusted by diluting the functionalized surfactant with a non-functionalized one. Fluorescence polarization analysis revealed that these dilutions result in the production of microdroplets with controlled azide surface density.

  • Developments and recent advancements in the field of endogenous amino acid selective bond forming reactions for bioconjugation

    Oleksandr Koniev, Alain Wagner
    Chemical Society Reviews, 2015, 44 (15), pp.5495 - 5551. ⟨10.1039/c5cs00048c⟩
    Article dans une revue

    Bioconjugation methodologies have proven to play a central enabling role in the recent development of biotherapeutics and chemical biology approaches. Recent endeavours in these fields shed light on unprecedented chemical challenges to attain bioselectivity, biocompatibility, and biostability required by modern applications. In this review the current developments in various techniques of selective bond forming reactions of proteins and peptides were highlighted. The utility of each endogenous amino acid-selective conjugation methodology in the fields of biology and protein science has been surveyed with emphasis on the most relevant among reported transformations; selectivity and practical use have

  • Photopolymerized micelles of diacetylene amphiphile: physical characterization and cell delivery properties

    Patrick Neuberg, Aurélia Perino, Emmanuelle Morin-Picardat, Nicolas Anton, Zeinab Darwich, Denis Weltin, Yves Mely, Andrey Klymchenko, Jean-Serge Remy, Alain Wagner
    Chemical Communications, 2015, 51 (58), pp.11595-11598. ⟨10.1039/c5cc03820k⟩
    Article dans une revue

    A series of polydiacetylene (PDA) - based micelles were prepared from diacetylenic surfactant bearing polyethylene glycol, by increasing UV-irradiation times. These polymeric lipid micelles were analyzed by physicochemical methods, electron microscopy and NMR analysis. Cellular delivery of fluorescent dye suggests that adjusting the polymerization state is vital to reach the full in vitro potential of PDA-based delivery systems.

  • Copper‐Chelating Azides for Efficient Click Conjugation Reactions in Complex Media

    Valentina Bevilacqua, Mathias King, Manon Chaumontet, Marc Nothisen, Sandra Gabillet, David Buisson, Céline Puente, Alain Wagner, Frédéric Taran
    Angewandte Chemie International Edition, 2014, 53 (23), pp.5872-5876. ⟨10.1002/anie.201310671⟩
    Article dans une revue

    Abstract The concept of chelation‐assisted copper catalysis was employed for the development of new azides that display unprecedented reactivity in the copper(I)‐catalyzed azide–alkyne [3+2] cycloaddition (CuAAC) reaction. Azides that bear strong copper‐chelating moieties were synthesized; these functional groups allow the formation of azide copper complexes that react almost instantaneously with alkynes under diluted conditions. Efficient ligation occurred at low concentration and in complex media with only one equivalent of copper, which improves the biocompatibility of the CuAAC reaction. Furthermore, such a click reaction allowed the localization of a bioactive compound inside living cells by fluorescence measurements.

  • Bio-specific and bio-orthogonal chemistries to switch-off the quencher of a FRET-based fluorescent probe: application to living-cell biothiol imaging

    Coraline Egloff, Sylvain Jacques, Marc Nothisen, D Weltin, C Calligaro, Michel Mosser, Jean-Serge Remy, Alain Wagner
    Chemical Communications, 2014, 50 (70), pp.10049-10051. ⟨10.1039/c4cc03548h⟩
    Article dans une revue

    We report the first molecular system that is responsive to both a bio-specific and a bio-orthogonal stimulus. This dual activation process was applied to the design of a biothiol-specific FRET-based fluorescent probe that could be turned-on via an original concept of quencher bleaching

  • NaNO2 -Mediated Transformation of Aliphatic Secondary Nitroalkanes into Ketones or Oximes under Neutral, Aqueous Conditions. On How the Nitro Derivative Catalyzes its Own Transformation

    Arnaud Gissot, N'Gouela Sylvère, Christophe Matt, Alain Wagner, Charles Mioskowski
    Journal of Organic Chemistry, 2014, ⟨10.1021/jo0489824⟩
    Article dans une revue

    The nitrosation of secondary nitro derivatives into ketones or oximes depending on the nitro substituents has been reinvestigated. The reaction efficiently takes place under neutral conditions thus allowing acid-sensitive substrates to be converted in very good yields. The generation of nitrosating species under such mild conditions is unprecedented. Mechanistic investigations strongly suggest that they result from the nucleophilic attack of the nitrite anion on the aci-nitro(nate) form of the secondary nitroalkane. The latter acts in turn as an auto-catalyst for its own transformation by means of the nitrosating species generated in situ from it.

  • 4-Halogeno-sydnones for fast strain promoted cycloaddition with bicyclo-[6.1.0]-nonyne

    Lucie Plougastel, Oleksandr Koniev, Simon Specklin, Elodie Decuypere, Christophe Créminon, David-Alexandre Buisson, Alain Wagner, Sergii Kolodych, Frédéric Taran
    Chemical Communications, 2014, 50 (66), pp.9376-9378. ⟨10.1039/c4cc03816a⟩
    Article dans une revue

    4-Halogeno-sydnones were found to be efficient dipole partners for the strain promoted click reaction with bicyclo-[6.1.0]-nonyne. This bioorthogonal reaction has been applied to protein labeling.

  • Towards a KCC2 blocker pharmacophore model

    Florence Lebon, Cécile Pégurier, Marie Ledecq, Benoit Mathieu, Nathalie Bosman, Anne Frycia, Sébastien Lengelé, Kashinath Dhurke, Ananda Kumar Kanduluru, Stéphane Meunier, Alain Wagner, Christian Wolff, Laurent Provins
    Bioorganic and Medicinal Chemistry Letters, 2012, 22 (12), pp.3978-3982. ⟨10.1016/j.bmcl.2012.04.097⟩
    Article dans une revue

  • A REPRESENTATION TO APPLY USUAL DATA MINING TECHNIQUES TO CHEMICAL REACTIONS — ILLUSTRATION ON THE RATE CONSTANT OF S N 2 REACTIONS IN WATER

    Frank Hoonakker, Nicolas Lachiche, Alexandre Varnek, Alain Wagner
    International Journal on Artificial Intelligence Tools, 2012, 20 (02), pp.253-270. ⟨10.1142/s0218213011000140⟩
    Article dans une revue

    Chemical reactions always involve several molecules of two types, reactants and products. Existing data mining techniques, eg. Quantitative Structure Activity Relationship (QSAR) methods, deal with individual molecules only. In this article, we propose to use a Condensed Graph of Reaction (CGR) to merge all molecules involved in a reaction into one molecular graph. This allows one to consider reactions as pseudo-molecules and to develop QSAR models based on fragment descriptors. Then ISIDA (In SIlico Design and Analysis) fragment descriptors built from CGRs are used to generate models for the rate constant of S N 2 reactions in water, using three usual attribute-value regression algorithms (linear regression, support vector machine, and regression trees). This approach is compared favorably to two state-of-the-art relational data mining techniques.

  • Trimethoxyarene as a Highly Ionizable Tag for Reaction Analysis by Atmospheric Pressure Photoionization Mass Spectrometry (APPI/MS): Exploration of Heterocyclic Synthesis

    Mathieu Bui The Thuong, Cédric Catala, Cyril Colas, Christine Schaeffer, Alain van Dorsselaer, André Mann, Alain Wagner
    European Journal of Organic Chemistry, 2012, 2012 (1), pp.85-92. ⟨10.1002/ejoc.201100919⟩
    Article dans une revue

    Abstract A mass spectrometry (MS) method was developed to rapidly analyze crude reaction mixtures. This method relies on highly effective ionization by atmospheric pressure photoionization (APPI) of molecules with a prosthetic trimethoxyarene (TMOA) residue. In a crude reaction mixture, products resulting from the reaction of the TMOA‐labeled substrate will be selectively ionized to afford an easily readable mass spectrum. Interestingly, we noticed that TMOA‐labeled molecules were not fragmented and gave the preferred [M + H] + ion peak. This APPI‐MS reaction mixture analysis method was used for the optimization of heterocycle synthesis. By comparing results obtained by APPI/MS, GC, and HPLC analysis, it appeared that a semi‐quantification could be achieved by integrating the MS peak intensities.

  • Stereoselective Addition of Grignard Reagents to New P ‐Chirogenic N ‐Phosphinoylbenzaldimines: Effect of the Phosphorus Substituents on the Stereoselectivity

    Irene Notar Francesco, Coraline Egloff, Alain Wagner, Françoise Colobert
    European Journal of Organic Chemistry, 2011, 2011 (20-21), pp.4037-4045. ⟨10.1002/ejoc.201100380⟩
    Article dans une revue

    Abstract Several phosphinoylimines have been synthesized in five steps by starting from the appropriate phosphane oxide and were then treated with methylmagnesium bromide to give both diastereoisomers in high yields and with promising diastereomeric ratios. Then N ‐[( tert ‐butyl)(phenyl)phosphinoyl]benzaldimine, which displayed the best results, was subjected to the 1,2‐addition of various Grignard reagents to evaluate the best chiral induction due to the stereogenic phosphorus atom. The corresponding adducts were obtained in excellent yields and with moderate to excellent diastereoisomeric ratios.

  • First efficient uncharged reactivators for the dephosphylation of poisoned human acetylcholinesterase.

    Guillaume Mercey, Tristan Verdelet, Géraldine Saint-André, Emilie Gillon, Alain Wagner, Rachid Baati, Ludovic Jean, Florian Nachon, Pierre-Yves Renard
    Chemical Communications, 2011, 47 (18), pp.5295-5297. ⟨10.1039/c1cc10787a⟩
    Article dans une revue

    Nerve agents are highly toxic organophosphorus compounds with strong inhibition potency against acetylcholinesterase (AChE). Herein, we describe two first extremely promising uncharged reactivators for poisoned human AChE with a superior or similar in vitro ability to reactivate the enzyme as compared to that of HI-6, obidoxime, TMB-4 and HLö-7.

  • Synthesis and Radioprotective Properties of Pulvinic Acid Derivatives

    Antoine Le Roux, Stéphane Meunier, Thierry Le Gall, Jean‐marc Denis, Pierre Bischoff, Alain Wagner
    ChemMedChem, 2011, 6 (3), pp.561-569. ⟨10.1002/cmdc.201000391⟩
    Article dans une revue

    Abstract A high‐throughput screening method has highlighted the marked antioxidant activity of some pulvinic acid derivatives (PADs) towards oxidation of thymidine, under γ and UV irradiation, and Fenton‐like conditions. Here, we report the synthesis of a series of new hydrophilic PADs and the evaluation of their radioprotective efficacy in cell culture. Using a cell‐based fluorescent assay, we show that some of these compounds have a pronounced ability to prevent cell death caused by radiation and to allow the subsequent resumption of proliferation. Thus, PADs may be considered as a novel class of radioprotective agents.

  • Structure and behavior of polydiacetylene-based micelles

    Aurélia Perino, Andrey Klymchenko, Alexandre Morere, Emmanuel Contal, Alain Rameau, Jean-Michel Guenet, Yves Mély, Alain Wagner
    Macromolecular Chemistry and Physics, 2010, 212 (2), pp.111-117. ⟨10.1002/macp.201000459⟩
    Article dans une revue

    The effect of photopolymerization on the structure, stability and encapsulation properties of polydiacetylene micelles containing nitrilotriacetic acid head groups are investigated. Micellar nanostructures of 7–10 nm diameter are identified that are invariant after polymerization. In the micelles, the polymerized ene-yne chains are much shorter than in planar lipid membranes. SANS confirmed the presence of a monodisperse population of small particles before and after polymerization. It is shown that the CMC decreases manifold after micelle photopolymerization, indicating that it stabilizes the micellar structure. After photopolymerization, these micelles preserved their strong ability to solubilize a hydrophobic pigment, which makes them potentially interesting as drug delivery vehicles.

  • Fine-Tuning the Morphology of Self-Assembled Nanostructures of Propargyl Ammonium-Based Amphiphiles

    Emmanuelle Morin, Jean-Michel Guenet, David D. Díaz, Jean-Serge Remy, Alain Wagner
    Journal of Physical Chemistry B, 2010, 114 (39), pp.12495-12500. ⟨10.1021/jp104911e⟩
    Article dans une revue

    N-Methyl-N-(pentacosa-10,12-diyn)-propargylamine organizes itself into an unusual supramolecular pH- and thermo-responsive system. Studies have showed that submillimetric length hollow laths form this unique structure in the presence of hydrochloric acid. Specific chemical modifications on the initial molecule and small-angle neutron scattering experiments were performed to understand the structure of this system. Our results allow us to suggest a possible structure of the laths.

  • A HTS assay for the detection of organophosphorus nerve agent scavengers.

    Ludivine Louise-Leriche, Emilia Paunescu, Géraldine Saint-André, Rachid Baati, Anthony Romieu, Alain Wagner, Pierre-Yves Renard
    Chemistry - A European Journal, 2010, 16 (11), pp.3510-3523. ⟨10.1002/chem.200902986⟩
    Article dans une revue

    A new pro-fluorescent probe aimed at a HTS assay of scavengers is able to selectively and efficiently cleave the P-S bond of organophosphorus nerve agents and by this provides non-toxic phosphonic acid has been designed and synthesised. The previously described pro-fluorescent probes were based on a conventional activated P-Oaryl bond cleavage, whereas our approach uses a self-immolative linker strategy that allows the detection of phosphonothioase activity with respect to a non-activated P-Salkyl bond. Further, we have also developed and optimised a high-throughput screening assay for the selection of decontaminants (chemical or biochemical scavengers) that could efficiently hydrolyse highly toxic V-type nerve agents. A preliminary screening, realised on a small alpha-nucleophile library, allowed us to identify some preliminary "hits", among which pyridinealdoximes, alpha-oxo oximes, hydroxamic acids and, less active but more original, amidoximes were the most promising. Their selective phosphonothioase activity has been further confirmed by using PhX as the substrate, and thus they offer new perspectives for the synthesis of more potent V nerve agent scavengers.

  • New Cyclotrimerization of Aldehydes to Cyclopentenone or Tetrahydrofuran Induced by Dibromotriphenylphosphorane

    Marie-Pierre Heck, Christophe Matt, Alain Wagner, Loic Toupet, Charles Mioskowski
    European Journal of Organic Chemistry, 2010, 2010 (5), pp.966--971. ⟨10.1002/ejoc.200901105⟩
    Article dans une revue

    alpha-Mono- or alpha-dialkylated aldehydes undergo cyclotrimerization in the presence of dibromotriphenylphosphorane (PPh(3)Br(2)) to afford cyclopentenones or tetrasubstituted tetrahydrofurans in good yields. These transformations proceed by a tandem aldol dimerization/Nazarov reaction or a tandem aldol dimerization/Prins cyclization.

  • Structure-activity relationship study of betulinic acid, a novel and selective TGR5 agonist, and its synthetic derivatives: potential impact in diabetes

    Cédric Genet, Axelle Strehle, Céline Schmidt, Geoffrey Boudjelal, Annelise Lobstein, Kristina Schoonjans, Michel Souchet, Johan Auwerx, Régis Saladin, Alain Wagner
    Journal of Medicinal Chemistry, 2010, 53 (1), pp.178-190. ⟨10.1021/jm900872z⟩
    Article dans une revue

    We describe here the biological screening of a collection of natural occurring triterpenoids against the G protein-coupled receptor TGR5, known to be activated by bile acids and which mediates some important cell functions. This work revealed that betulinic (1), oleanolic (2), and ursolic acid (3) exhibited TGR5 agonist activity in a selective manner compared to bile acids, which also activated FXR, the nuclear bile acid receptor. The most potent natural triterpenoid betulinic acid was chosen as a reference compound for an SAR study. Hemisyntheses were performed on the betulinic acid scaffold, and we focused on structural modifications of the C-3 alcohol, the C-17 carboxylic acid, and the C-20 alkene. In particular, structural variations around the C-3 position gave rise to major improvements of potency exemplified with derivatives 18 dia 2 (RG-239) and 19 dia 2. The best derivative was tested in vitro and in vivo, and its biological profile is discussed.

  • Anti-hyperglycemic activity of a TGR5 agonist isolated from Olea europaea.

    Hiroyuki Sato, Cédric Genet, Axelle Strehle, Charles Thomas, Annelise Lobstein, Alain Wagner, Charles Mioskowski, Johan Auwerx, Régis Saladin
    Biochemical and Biophysical Research Communications, 2007, 362 (4), pp.793-8. ⟨10.1016/j.bbrc.2007.06.130⟩
    Article dans une revue

    Olive tree (Olea europeaea) leaves are well known for their effect on metabolism in particular as a traditional anti-diabetic and anti-hypertensive herbal drug. These properties are until now only attributed to oleuropein, the major secoiridoid of olive leaves. Here we describe the isolation and the identification of another constituent implicated in the anti-diabetic effect of this plant, i.e. oleanolic acid. We show that this triterpene is an agonist for TGR5, a member of G-protein coupled receptor activated by bile acids and which mediates some of their various cellular and physiological effect. Oleanolic acid lowers serum glucose and insulin levels in mice fed with a high fat diet and it enhances glucose tolerance. Our data suggest that both oleuropein and oleanolic acid are involved in the anti-diabetic effect of olive leaves and further emphasize the potential role of TGR5 agonists to improve metabolic disorders.

  • An efficient synthesis of biaryls via noncatalysed anionic coupling of an arylsodium with haloarenes

    Jean-Michel Becht, Arnaud Gissot, Alain Wagner, Charles Mioskowski
    Tetrahedron Letters, 2004, 45 (51), pp.9331-9333. ⟨10.1016/j.tetlet.2004.10.123⟩
    Article dans une revue

    Noncatalysed anionic coupling of an arylsodium with haloarenes readily gives access to valuable biaryl structures. Compared to aryllithiums, the reaction with arylsodiums is faster and can be performed at lower temperature. The coupling with substituted haloarenes proceeds often with a high degree of regioselectivity. Since only cheap and readily available substrates are involved, this coupling is particularly suited for the large scale synthesis of basic biaryl building blocks. Biaryls have found many applications in the fields of biologically active molecules, 1 molecular recognition, 2 nonlinear optic and ligands for catalysts. 3 They are generally synthesised in high yields and under mild reaction conditions through Pd-or Ni-catalysed cross coupling reactions. 4 Yet, Pd-catalysed cross couplings require organoboronic or organostannane reagents which are often tedious to prepare. Pd-or Ni-catalysts are also expensive and therefore quite unsuitable for the large scale preparation of basic biaryl building blocks. In this regard, we recently reported a straightforward noncatalysed anionic coupling of aryllithiums with haloarenes starting from readily available materials. 5 We have shown that the reaction of aryllithiums with substituted haloarenes proceeds often either via a regioselective aromatic nucleophilic substitution or via a regioselective addition of the aryllithium to an aryne intermediate. 5,6 We also demonstrated that arylsodiums offer an interesting alternative to aryllithiums especially in the large scale preparation of functionalised aromatic compounds. 7 Indeed, arylsodiums are obtained via an efficient one-pot ortho-metallation procedure of aromatic substrates with a sodiated organic base generated in situ from chlorooctane and stoichiometric amounts of metallic sodium. 7 Herein, we describe the reactivity and selectivity of the anionic coupling between an arylsodium and haloarenes and show the advantages associated with the use of an arylsodium in place of an aryllithium. The reactivity of arylsodiums was studied using 2-sodio-1,3-dimethoxybenzene 1 and chlorobenzene (X = Cl) as model substrates (Table 1). Inspired by our previous results, 5a 1,3-dimethoxybenzene was in situ ortho-metallated with the tandem chlorooctane/micronised sodium in THF at rt for 3 h. 7,8 Using the same reaction conditions than for aryllithiums, 5a chlorobenzene was added dropwise at rt and the reaction mixture was heated at 65°C for 60 min. We observed the exclusive formation of the biphenyl 3 in 75% yield, resulting probably from the reduction of 2 by the metallic sodium present in situ (entry 1). This hypothesis is supported by the excellent electron scavenging properties of biaryls. 9 Table 1. Optimisation of the reaction conditions Entry X Temp [ C] Time [min] 2 a [%] 3 a [%] Isolated overall yields after flash-chromatography on silica gel. Starting materials were recovered.

  • Buffer-induced, selective mono-C-alkylation of phloroglucinol: application to the synthesis of an advanced intermediate of catechin

    Arnaud Gissot, Alain Wagner, Charles Mioskowski
    Tetrahedron, 2004, 60 (32), pp.6807-6812. ⟨10.1016/j.tet.2004.06.026⟩
    Article dans une revue

    A straightforward mono-selective and C-specific alkylation of phloroglucinol with activated alkyl halides is presented. The use of water as solvent limits the amount of over-alkylated by-products. Provided some minor changes in the experimental conditions, hydrophobic cinnamyl halides can also be reacted, thus giving a direct access to advanced intermediates of natural flavonoids.

  • Reinvestigation of the Noncatalyzed Coupling of Aryllithium with Haloarene: A Novel Aromatic Nucleophilic Substitution Pathway

    Jean-Michel Becht, Arnaud Gissot, Alain Wagner, Charles Mioskowski
    Chemistry - A European Journal, 2003, ⟨10.1002/chem.200204373⟩
    Article dans une revue

    Noncatalyzed coupling reactions of aryllithiums and haloarenes proceed not only through the well-known aryne route but also, in some cases, through a novel addition-elimination pathway. Indeed, ortho-chloro-and ortho-bromomethoxyarenes lead selectively to the corresponding ortho-biaryls through a chelation-driven aromatic nucleophilic substitution pathway. Contrary to common belief, such noncatalyzed coupling reactions often proceed with high regioselectivity and high yield. These results underline the potency of such simple reactions and open up a straightforward access to a wide range of biaryl structures; this also appears particularly useful for large-scale and biaryl building-block syntheses, as only cheap and readily available substrates are involved.

  • Directed ortho-Metalation: a New Insight into Organosodium Chemistry

    Arnaud Gissot, Jean-Michel Becht, Jean Roger Desmurs, Virginie Pévère, Alain Wagner, Charles Mioskowski
    Angewandte Chemie International Edition, 2002, 41 (2), pp.340-343. ⟨10.1002/1521-3773(20020118)41:2<340::AID-ANIE340>3.0.CO;2-D⟩
    Article dans une revue

    Finely dispersed metallic sodium in combination with an alkyl chloride RCl can replace organolithium reagents in the ortho‐metalation of aromatic compounds (see scheme). The in situ generated base is consumed as soon as it is formed, which avoids Wurtz coupling, the usual side reaction, and the handling and storage of highly reactive alkyl sodium bases. Reaction conditions are mild, the reaction is easy to scale up, and the reagents needed are inexpensive.

  • Nitrolic acids: efficient precursors of nitrile oxides under neutral conditions

    Christophe Matt, Arnaud Gissot, Alain Wagner, Charles Mioskowski
    Tetrahedron Letters, 2000, 41 (8), pp.1191-1194. ⟨10.1016/S0040-4039(99)02278-9⟩
    Article dans une revue

    Nitrolic acids are prepared in good yields from primary nitroalkanes or primary alkyl bromides. Upon heating in THF, they afford the corresponding nitrile oxides under neutral conditions. In the presence of dipolarophiles, isoxazoles are obtained in yields up to 95%. For the less stable alkoxycarbonyl-and arylnitrolic acids the crude nitrolic acids can be directly engaged in the cycloaddition reaction. Nitrolic acids, obtained by careful addition of dilute acid to a mixture of nitroalkane anion and potassium nitrite, were first reported by Meyer in 1873. 1 Since then, only scanty reports dealing with their synthesis, stability and use are found in the literature. 2 We recently reported the transformation of primary nitroalkanes or primary alkyl bromides into carboxylic acids under mild conditions, using a mixture of acetic acid and sodium nitrite in DMSO at 50°C. 3 We noticed that, when the reaction is carried out at 20°C, the nitrolic acid, which is the intermediate of the above transformation, could be isolated in good yield. Nitrolic acids, prior to this work, were known to be highly unstable, difficult to handle and prone to decomposition upon heating via formation of the corresponding nitrile oxides. 4 For these reasons and presumably because of the lack of a simple and reliable method for their synthesis, thermolytic fragmentation of nitrolic acids has never been considered as a synthetically useful reaction for the generation of nitrile oxides. Herein we demonstrate the synthetic potential of our novel preparative method of nitrolic acids and investigate their use as precursors of nitrile oxides for 1,3-dipolar cycloadditions (Scheme 1). Scheme 1 * Corresponding authors. Fax: 33 3 88 67 88 91;

  • Communication dans un congrès
  • Structure/function studies of DNA gyrase supramolecular complexes

    Julie Papillon, Noëlle Potier, Corinne Crucifix, Jean-François Ménétret, Cédric Genet, Emmanuelle Leize-Wagner, Pierre Oudet, Alain Wagner, Patrick Schultz, Valérie Lamour
    36th FEBS Congress of the Biochemistry for Tomorrows Medicine, june 25-30, 2011, Torino, ITALY, Jun 2011, Torino, France
    Communication dans un congrès

  • Poster de conférence
  • Rapport
  • Rapport de conjoncture 2024 de la Commission Interdisciplinaire (CID) 52 Environnement & Société : du Savoir à l'Action du Comité National de la Recherche Scientifique du CNRS

    Vincent Lebreton, Sandrine Anquetin, David Biron, Sylvain Burri, Daniel Clesse, Benoît Cournoyer, François Criscuolo, Armelle Decaulne, Hervé Doreau, Alison Duncan, Véronique Eparvier, Romain Espinosa, Virginia Frey, Etienne Henry, Thomas Houet, Frédéric Lefevre, Julien Pétillon, Pierre P. Sasal, Yann Philippe Tastevin, Anne-Charlotte Vaissière, Alain Wagner
    CNRS. 2025, pp.16
    Rapport

    <div><p>Les défis environnementaux et sociétaux associés au dérèglement climatique et à l'érosion de la biodiversité posent la question cruciale de l'habitabilité de notre planète à court terme. La CID 52 Environnements Sociétés : du savoir à l'action développe une approche scientifique collective, interdisciplinaire et concertée pour répondre à cet enjeu, en cherchant des méthodologies et des solutions innovantes, inclusives et respectueuses des socio-écosystèmes. Face à l'urgence de la situation, la commission insiste sur les nécessaires collaborations entre scientifiques, décideurs et citoyens pour coproduire des solutions utiles et transformantes d'adaptation des sociétés aux changements globaux. Ces solutions explorent ainsi les changements sociaux, technologiques et des approches fondées sur la nature. Le rapport met aussi en avant l'importance d'une évaluation durable des solutions, tout en promouvant l'interdisciplinarité pour répondre aux crises globales. La CID 52 propose de renommer la commission Socioécosystèmes et crise environnementale globale : enjeux, savoirs et méthodologies pour des solutions durables, reflétant mieux l'intégration de ces recherches dans les politiques publiques pour une assimilation et une adaptation efficace et durable des populations humaines et non-humaines.</p></div>