Conjugates of modified cryptophycins and RGD-peptides enter target cells by endocytosis

J Med Chem. 2013 Mar 14;56(5):1853-64. doi: 10.1021/jm301346z. Epub 2013 Feb 22.

Abstract

Tumor targeting anticancer drug conjugates that contain a tumor recognition motif (homing device) are of high current relevance. Cryptophycins, naturally occurring cytotoxic cyclo-depsipeptides, have been modified by total synthesis to provide analogues suitable for conjugation to peptide-based homing devices. An array of functionalized β(2)-amino acids was synthesized and incorporated into cryptophycins. All analogues proved to be highly active in the cytotoxicity assay using the human cervix carcinoma cell line KB-3-1 and its multidrug-resistant subclone KB-V1. Conformational analysis of cryptophycin-52 and two synthetic analogues was performed by NMR and MD methods to obtain information on the influence of the unit C configuration on the overall conformation. An azide-functionalized cryptophycin was connected by CuAAC to an alkyne-containing fluorescently labeled cyclic RGD-peptide as the homing device for internalization studies. Confocal fluorescence microscopy proved integrin-mediated internalization by endocytosis and final lysosomal localization of the cryptophycin prodrug.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Depsipeptides / chemical synthesis
  • Depsipeptides / chemistry
  • Depsipeptides / metabolism*
  • Drug Resistance, Multiple
  • Drug Resistance, Neoplasm
  • Endocytosis*
  • Female
  • Humans
  • Inhibitory Concentration 50
  • Microscopy, Confocal
  • Molecular Dynamics Simulation
  • Nuclear Magnetic Resonance, Biomolecular
  • Oligopeptides / chemical synthesis
  • Oligopeptides / chemistry
  • Oligopeptides / metabolism*
  • Protein Conformation

Substances

  • Depsipeptides
  • Oligopeptides
  • arginyl-glycyl-aspartic acid