Chemical Macrocyclization of Peptides Fused to Antibody Fc Fragments
Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne , CH-1015 Lausanne, Switzerland.Bioconjugate Chemistry (Impact Factor: 4.51). 07/2012; 23(9):1856-63. DOI: 10.1021/bc300184m
To extend the plasma half-life of a bicyclic peptide antagonist, we chose to link it to the Fc fragment of the long-lived serum protein IgG1. Instead of chemically conjugating the entire bicyclic peptide, we recombinantly expressed its peptide moiety as a fusion protein to an Fc fragment and subsequently cyclized the peptide by chemically reacting its three cysteine residues with tris-(bromomethyl)benzene. This reaction was efficient and selective, yielding completely modified peptide fusion protein and no side products. After optimization of the linker and the Fc fragment format, the bicyclic peptide was fully functional as an inhibitor (K(i) = 76 nM) and showed an extended terminal half-life of 1.5 days in mice. The unexpectedly clean reaction makes chemical macrocyclization of peptide-Fc fusion proteins an attractive synthetic approach. Its good compatibility with the Fc fragment may lend the bromomethylbenzene-based chemistry also for the generation of antibody-drug conjugates.
Article: Polycyclic Peptide Therapeutics[Show abstract] [Hide abstract]
ABSTRACT: Owing to their excellent binding properties, high stability, and low off-target toxicity, polycyclic peptides are an attractive molecule format for the development of therapeutics. Currently, only a handful of polycyclic peptides are used in the clinic; examples include the antibiotic vancomycin, the anticancer drugs actinomycin D and romidepsin, and the analgesic agent ziconotide. All clinically used polycyclic peptide drugs are derived from natural sources, such as soil bacteria in the case of vancomycin, actinomycin D and romidepsin, or the venom of a fish-hunting coil snail in the case of ziconotide. Unfortunately, nature provides peptide macrocyclic ligands for only a small fraction of therapeutic targets. For the generation of ligands of targets of choice, researchers have inserted artificial binding sites into natural polycyclic peptide scaffolds, such as cystine knot proteins, using rational design or directed evolution approaches. More recently, large combinatorial libraries of genetically encoded bicyclic peptides have been generated de novo and screened by phage display. In this Minireview, the properties of existing polycyclic peptide drugs are discussed and related to their interesting molecular architectures. Furthermore, technologies that allow the development of unnatural polycyclic peptide ligands are discussed. Recent application of these technologies has generated promising results, suggesting that polycyclic peptide therapeutics could potentially be developed for a broad range of diseases.
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ABSTRACT: The synthesis and applications of the first water-soluble benzene derivative bearing a set of three different and orthogonal bioconjugatable groups (aminooxy, azido and thiol) are described. The combined use of a 5-amino isophthalic acid scaffold and unusual acid-labile protecting groups for temporarily masking aminooxy and thiol moieties has enabled the development of a highly convergent approach towards the synthesis of such a trivalent bioconjugation platform in good yields. The potential utility of this "ready-to-use" cross-linking reagent for creating complex and fragile tri-component (bio)molecular systems was illustrated through (1) the rapid preparation of a three-colour FRET cascade with valuable spectral properties and (2) the luminescent/fluorescent labelling of peptides and peptide-oligonucleotide conjugates. Thus, such (bio)molecular assemblies were readily obtained via a three-step process or in a "one-pot" manner, both involving oxime ligation, thiol-alkylation (SN2 or Michael addition) and copper-catalysed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) reactions.
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ABSTRACT: The notable expansion of peptide therapeutics development in the late 1990s and the 2000s led to an unprecedented number of marketing approvals in 2012 and has provided a robust pipeline that should deliver numerous approvals during the remainder of the 2010s. To document the current status of the pipeline, we collected data for peptide therapeutics in clinical studies and regulatory review, as well as those recently approved. In this Foundation review, we provide an overview of the pipeline, including therapeutic area and molecular targets, with a focus on glucagon-like peptide 1 receptor agonists. Areas for potential expansion, for example constrained peptides and peptide-drug conjugates, are profiled.
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