1,2,3-Triazole Stabilized Neurotensin-Based Radiopeptidomimetics for Improved Tumor Targeting

Bioconjug Chem. 2015 Oct 21;26(10):2143-52. doi: 10.1021/acs.bioconjchem.5b00444. Epub 2015 Sep 18.

Abstract

Neurotensin (NT) is a regulatory peptide with nanomolar affinity toward NT receptors, which are overexpressed by different clinically relevant tumors. Its binding sequence, NT(8-13), represents a promising vector for the development of peptidic radiotracers for tumor imaging and therapy. The main drawback of the peptide is its short biological half-life due to rapid proteolysis in vivo. Herein, we present an innovative strategy for the stabilization of peptides using nonhydrolizable 1,4-disubstituted, 1,2,3-triazoles as amide bond surrogates. A "triazole scan" of the peptide sequence yielded novel NT(8-13) analogues with enhanced stability, retained receptor affinity, and improved tumor targeting properties in vivo. The synthesis of libraries of triazole-based peptidomimetics was achieved efficiently on solid support by a combination of Fmoc-peptide chemistry, diazo transfer reactions, and the Cu(I)-catalyzed alkyne azide cycloaddition (CuAAC) employing methods that are fully compatible with standard solid phase peptide synthesis (SPPS) chemistry. Thus, the amide-to-triazole substitution strategy may represent a general methodology for the metabolic stabilization of biologically active peptides.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacokinetics*
  • Chemistry Techniques, Synthetic
  • Cycloaddition Reaction
  • Female
  • HT29 Cells
  • Half-Life
  • Humans
  • Isotope Labeling / methods
  • Lutetium / chemistry
  • Mice, Nude
  • Molecular Targeted Therapy / methods
  • Neurotensin / chemistry*
  • Peptide Fragments / chemistry*
  • Peptidomimetics / chemistry*
  • Peptidomimetics / pharmacokinetics
  • Radioisotopes / chemistry*
  • Receptors, Neurotensin / metabolism
  • Structure-Activity Relationship
  • Tissue Distribution
  • Triazoles / chemistry*
  • Xenograft Model Antitumor Assays

Substances

  • Antineoplastic Agents
  • Peptide Fragments
  • Peptidomimetics
  • Radioisotopes
  • Receptors, Neurotensin
  • Triazoles
  • neurotensin type 1 receptor
  • Neurotensin
  • Lutetium
  • neurotensin (8-13)