0000000001302169
AUTHOR
Coline Canovas
Titanium imido complexes stabilised by bis(iminophosphoranyl)methanide ligands: the influence of N-substituents on solution dynamics and reactivity
Terminal titanium imido complexes of the general formula [Ti(N(t)Bu)Cl{CH(Ph2PNR)2}] 4 (R = Ph, (i)Pr, (t)Bu) are reported. These compounds were synthesized from the corresponding Li adducts 3 of BIPMH (bis(iminophosphoranyl)methanide) and Mountford's complex [Ti(N(t)Bu)Cl2(Py)3]. The crystal structures of two of the Ti complexes (R = Ph, (t)Bu) and two of the Li compounds (R = (i)Pr, (t)Bu) are reported. Dynamic solution NMR spectroscopy reveals a dynamic isomerisation process in the case of the Ti complex 4c (R = (t)Bu). DFT studies showed that this dynamic process comes from steric repulsion between the imido ligand and the (t)Bu N-substituents on the BIPMH ligand. Complexes 4 were teste…
Site-specific near-infrared fluorescent labelling of proteins on cysteine residues with meso -chloro-substituted heptamethine cyanine dyes
International audience; Near-infrared (NIR) fluorescence imaging is a promising new medical imaging modality. Associated with a targeting molecule, NIR fluorophores can accumulate selectively in tissues of interest and become valuable tools for the diagnosis and therapy of various pathologies. To facilitate the design of targeted NIR imaging agents, it is important to identify simple and affordable fluorescent probes, allowing rapid labelling of biovectors such as proteins, ideally in a site-specific manner. Here, we demonstrate that heptamethine cyanine based fluorophores, such as IR-783, that contain a chloro-cyclohexyl moiety within their polymethine chain can react selectively, at neutr…
Modular Assembly of Multimodal Imaging Agents through an Inverse Electron Demand Diels–Alder Reaction
International audience; The combination of two imaging probes on a same biomolecule gives access to targeted bimodal imaging agents that can provide more accurate diagnosis, complementary information, or that may be used in different applications, such as PET imaging and fluorescence imagingassisted surgery. In this study, we demonstrate that dichlorotetrazine, a small, commercially available compound, can be used as a modular platform to easily assemble various imaging probes. Doubly-labeled tetrazines can then be conjugated to a protein through a biorthogonal IEDDA reaction. A series of difunctionalized tetrazine compounds containing various chelating agents and fluorescent dyes was synth…
New site-specific bioconjugation strategies and their application to the development of molecular imaging agents for cancer diagnostic
The preparation of targeted imaging agents suitable for cancer diagnostic involves the coupling of an imaging probe to a vector, generally a protein, able to specifically target cancerous tissues. Unfortunately, this bioconjugation step is often problematic. Indeed, proteins present a large variety of reactive functions that can potentially interfere with the coupling reaction. The purpose of this work is the design of innovative selective bioconjugation strategies that can facilitate the synthesis of molecular imaging agents.Our research led to the development of a simple and efficient approach allowing the modification of a protein with a fluorophore by using a site-specific bioconjugatio…
Site-Specific Dual Labeling of Proteins on Cysteine Residues with Chlorotetrazines
International audience; Dual-labeled biomolecules constitute a new generation of bioconjugates with promising applications in therapy and diagnosis. Unfortunately, the development of these new families of biologics is hampered by the technical difficulties associated with their construction. In particular, the site specificity of the conjugation is critical as the number and position of payloads can have a dramatic impact on the pharmacokinetics of the bioconjugate. Herein, we introduce dichlorotetrazine as a trivalent platform for the selective double modification of proteins on cysteine residues. This strategy is applied to the dual labeling of albumin with a macrocyclic chelator for nucl…
(R)-NODAGA-PSMA: A Versatile Precursor for Radiometal Labeling and Nuclear Imaging of PSMA-Positive Tumors
Purpose The present study aims at developing and evaluating an urea-based prostate specific membrane antigen (PSMA) inhibitor suitable for labeling with 111In for SPECT and intraoperative applications as well as 68Ga and 64Cu for PET imaging. Methods The PSMA-based inhibitor-lysine-urea-glutamate-coupled to the spacer Phe-Phe-D-Lys(suberoyl) and functionalized with the enantiomerically pure prochelator (R)-1-(1-carboxy-3-carbotertbutoxypropyl)-4,7-carbotartbutoxymethyl)-1,4,7-triazacyclononane ((R)-NODAGA(tBu)3), to obtain (R)-NODAGA-Phe-Phe-D-Lys(suberoyl)-Lys-urea-Glu (CC34). CC34 was labeled with 111In, 68Ga and 64Cu. The radioconjugates were further evaluated in vitro and in vivo in LNC…
Site-Specific Dual-Labeling of a VHH with a Chelator and a Photosensitizer for Nuclear Imaging and Targeted Photodynamic Therapy of EGFR-Positive Tumors
Simple Summary Variable domains of heavy chain only antibodies are small proteins that can be used for tumor imaging and therapy upon conjugation of functional groups. As frequently used random conjugation techniques can decrease binding to the target of interest, site-specific conjugation of these functional groups is preferred. Here, we optimized site-specific conjugation of both a chelator for binding of a radiometal and a photosensitizer to epidermal growth factor receptor (EGFR) binding VHH 7D12. We characterized this dual-labeled VHH for nuclear imaging and targeted photodynamic therapy of EGFR-expressing tumors. Abstract Variable domains of heavy chain only antibodies (VHHs) are valu…
CCDC 987356: Experimental Crystal Structure Determination
Related Article: Adrien T. Normand, Alexandre Massard, Philippe Richard, Coline Canovas, Cédric Balan, Michel Picquet, Audrey Auffrant, Pierre Le Gendre|2014|Dalton Trans.|43|15098|doi:10.1039/C4DT00746H
CCDC 987359: Experimental Crystal Structure Determination
Related Article: Adrien T. Normand, Alexandre Massard, Philippe Richard, Coline Canovas, Cédric Balan, Michel Picquet, Audrey Auffrant, Pierre Le Gendre|2014|Dalton Trans.|43|15098|doi:10.1039/C4DT00746H
CCDC 987357: Experimental Crystal Structure Determination
Related Article: Adrien T. Normand, Alexandre Massard, Philippe Richard, Coline Canovas, Cédric Balan, Michel Picquet, Audrey Auffrant, Pierre Le Gendre|2014|Dalton Trans.|43|15098|doi:10.1039/C4DT00746H
CCDC 987358: Experimental Crystal Structure Determination
Related Article: Adrien T. Normand, Alexandre Massard, Philippe Richard, Coline Canovas, Cédric Balan, Michel Picquet, Audrey Auffrant, Pierre Le Gendre|2014|Dalton Trans.|43|15098|doi:10.1039/C4DT00746H