Design, synthesis, and biological evaluation of a dual tumor-specific motive containing integrin-targeted plasmin-cleavable doxorubicin prodrug

Mol Cancer Ther. 2002 Sep;1(11):901-11.

Abstract

The design, synthesis, and initial biological evaluation of a doxorubicin prodrug that contains a dual tumor specific moiety, which allows enhanced tumor recognition potential, is reported. Both a tumor-specific recognition site and a tumor selective enzymatic activation sequence are incorporated in the prodrug. The first tumor-specific sequence is the bicyclic CDCRGDCFC (RGD-4C) peptide that selectively binds alpha v beta 3 and alpha v beta 5 integrins. These integrins are highly overexpressed on invading tumor endothelial cells. The second tumor-specific sequence is a D-Ala-Phe-Lys tripeptide that is selectively recognized by the tumor-associated protease plasmin, which is involved in tumor invasion and metastasis. An aminocaproyl residue was incorporated as a spacer between the two peptide sequences, whereas a self-eliminating 4-aminobenzyl alcohol spacer was inserted between the plasmin substrate and doxorubicin. Although the prodrug showed a decreased binding affinity as compared with the unconjugated reference peptide, it was still a potent ligand for alpha v beta 3 and alpha v beta 5 integrin receptors. The synthesized construct also possessed plasmin substrate properties as demonstrated by doxorubicin release from 1 upon incubation with plasmin. The release of doxorubicin from 1 was not complete, possibly related to low prodrug solubility. In vitro prodrug 1 showed plasmin-dependent cytotoxicity for endothelial cells and HT1080 fibrosarcoma cells. On the basis of these in vitro results, derivatives of 1 with improved water solubility are considered good candidates for additional development and in vivo evaluation of this dual targeting concept.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antineoplastic Agents / chemical synthesis*
  • Antineoplastic Agents / pharmacology
  • Benzyl Alcohols / pharmacology
  • Binding Sites
  • Cell Adhesion
  • Chromatography, High Pressure Liquid
  • Dose-Response Relationship, Drug
  • Doxorubicin / pharmacology*
  • Drug Design*
  • Endothelium / cytology
  • Endothelium, Vascular / cytology
  • Fibrinolysin / chemistry
  • Fibrinolysin / metabolism
  • Humans
  • Inhibitory Concentration 50
  • Integrin alphaVbeta3 / metabolism
  • Integrins / chemistry
  • Integrins / metabolism
  • Ligands
  • Models, Chemical
  • Molecular Sequence Data
  • Neoplasm Invasiveness
  • Neoplasm Metastasis
  • Oligopeptides
  • Peptides / chemistry
  • Prodrugs / chemical synthesis
  • Prodrugs / pharmacology*
  • Protein Binding
  • Protein Structure, Tertiary
  • Receptors, Vitronectin / metabolism

Substances

  • Antineoplastic Agents
  • Benzyl Alcohols
  • Integrin alphaVbeta3
  • Integrins
  • Ligands
  • Oligopeptides
  • Peptides
  • Prodrugs
  • Receptors, Vitronectin
  • integrin alphaVbeta5
  • 4-aminobenzyl alcohol
  • arginyl-glycyl-aspartic acid
  • Doxorubicin
  • Fibrinolysin