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Peptide-based Identification of Functional Motifs and their Binding Partners
14:28

Peptide-based Identification of Functional Motifs and their Binding Partners

Published on: June 30, 2013

G Czerwinski1, N I Tarasova, C J Michejda

  • 1Molecular Aspects of Drug Design Section, Macromolecular Structure Laboratory, Advanced BioScience Laboratories-Basic Research Program, National Cancer Institute, Frederick Cancer Research and Development Center, Frederick, MD 21702, USA.

Proceedings of the National Academy of Sciences of the United States of America
|September 30, 1998
PubMed

Insights

This study developed a targeted anticancer drug using heptagastrin to deliver a cytotoxic agent to tumor cells overexpressing the gastrin/cholecystokinin type B receptor, achieving high efficacy with no general toxicity.

Area of Science:

  • Pharmacology
  • Oncology
  • Molecular Biology

Background:

  • Cell surface receptors overexpressed in tumors offer potential targets for drug delivery.
  • Receptor-targeted drug design requires careful consideration of ligand-drug conjugation and trafficking.

Purpose of the Study:

  • To identify key elements for successful receptor-targeted anticancer drugs.
  • To evaluate a novel drug conjugate targeting the gastrin/cholecystokinin type B receptor.

Main Methods:

  • Synthesis and evaluation of heptagastrin linked to an ellipticine derivative.
  • Assessment of drug-receptor interactions, cellular trafficking, and in vitro/in vivo efficacy.
  • Comparison of toxicity in receptor-positive versus receptor-negative cells.

Main Results:

  • The drug-ligand conjugate was sorted to lysosomes, while the receptor was recycled to the plasma membrane.
  • A specific linker (succinoyl-substituted pentapeptide) enhanced toxicity to receptor-positive cells by over 1000-fold.
  • The conjugated drug eradicated receptor-positive tumor cells in vivo without systemic toxicity.

Conclusions:

  • Receptor density, cytotoxic moiety properties, and lysosomal processing are critical for effective receptor-targeted drug therapy.
  • This approach shows promise for selective and potent cancer treatment.

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