Endothelial cells internalize and degrade RGD-modified proteins developed for tumor vasculature targeting

AJ Schraaa*, RJ Kok, AD Berendsen, HE Moorlag, EJ Bos, DKF Meijer, LFMH de Leij, G Molema

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

61 Citations (Scopus)

Abstract

Tumor vasculature can be targeted by peptides containing an RGD (Arg-Gly-Asp) sequence, which bind to a p, and alpha(v)beta(5) integrins on angiogenic endothelial cells. By covalently attaching cyclic RGD-peptides (cRGDfK) to a protein backbone, we prepared a multivalent peptide-protein conjugate with increased affinity for alpha(v)beta(3)/alpha(v)beta(5) integrins. We demonstrated that RGDpep-protein conjugate bound to HUVEC, whereas the conjugate prepared with the control RAD peptide was devoid of any binding. RGDpep-protein conjugate was furthermore functional in inhibiting the adhesion of HUVEC to alpha(v)beta(3)/alpha(v)beta(5) ligand vitronectin, and direct binding of the radiolabeled conjugate to HUVEC was inhibited by alpha(v)beta(3)/alpha(v)beta(5)-specific RGD peptides. Finally, RGDpep-protein conjugate was shown to be internalized and degraded by HUVEC, a process that could be inhibited by lysosomal degradation inhibitors chloroquine and ammonium chloride. This cellular handling was significantly influenced by the presence of cations, which strongly inhibited internalization. This is the first study that shows direct evidence that primary endothelial cells are capable of internalizing RGD-containing macromolecular proteins. This feature makes them attractive carriers for the intracellular delivery of potent anti-angiogenic drugs into endothelial cells for the treatment of cancer and chronic inflammatory diseases. (C) 2002 Elsevier Science B.V. All rights reserved.

Original languageEnglish
Article numberPII S0168-3659(02)00206-7
Pages (from-to)241-251
Number of pages11
JournalJournal of Controlled Release
Volume83
Issue number2
Publication statusPublished - 4-Oct-2002

Keywords

  • alpha(v)beta(3)
  • RGD peptide
  • macromolecular drug carrier
  • intracellular delivery
  • tumor vasculature targeting
  • INTEGRIN ALPHA(V)BETA(3)
  • ANGIOGENESIS
  • ALPHA-V-BETA-3
  • APOPTOSIS
  • PEPTIDES
  • VITRONECTIN
  • DELIVERY
  • RECEPTOR
  • CANCER
  • ANTAGONIST

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