Synthesis and biological activity assay of novel camptothecin-peptidic conjugates based on PEPT1

Qiang Zhang1, Ping Zou1, Meixuan Zhu2

  • 1Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Science, Northeast Forestry University, Harbin, China.

Insights

This study developed novel camptothecin (CPT) prodrugs targeting peptide transporter 1 (PEPT1) overexpressed in cancer cells. These CPT-peptidic conjugates show promise for improved tumor selectivity and enhanced cancer treatment efficacy.

Area of Science:

  • Medicinal Chemistry
  • Cancer Biology
  • Pharmacology

Background:

  • Camptothecin (CPT) derivatives are promising cancer therapeutics but suffer from poor selectivity and toxicity.
  • Peptide transporter 1 (PEPT1), highly expressed in the intestine, is also overexpressed in various cancer cells, presenting a potential therapeutic target.
  • Targeting PEPT1 could improve drug bioavailability and enable cancer-specific delivery.

Purpose of the Study:

  • To design and synthesize novel camptothecin (CPT) prodrugs conjugated with peptides for targeted delivery to PEPT1-overexpressing cancer cells.
  • To evaluate the affinity, cellular uptake, and cytotoxicity of these CPT prodrugs in cancer cells with varying levels of PEPT1 expression.

Main Methods:

  • Synthesis and structural confirmation of eighteen CPT-peptidic conjugates using NMR and HRMS.
  • Assessment of PEPT1 protein expression in different cell lines via immunofluorescence and Western blotting.
  • Evaluation of prodrug cytotoxicity and PEPT1-mediated uptake through competition assays with Gly-Sar.

Main Results:

  • The synthesized CPT-peptidic conjugates demonstrated significant inhibition of Gly-Sar uptake, indicating high affinity for PEPT1.
  • Prodrugs exhibited enhanced cellular uptake in PEPT1-overexpressing cells compared to PEPT1-underexpressing cells.
  • Most CPT prodrugs showed superior inhibition of cancer cell growth in PEPT1-high expressing cells.

Conclusions:

  • Peptidic prodrugs targeting PEPT1 offer a viable strategy for enhancing the tumor selectivity of camptothecin (CPT).
  • This approach holds significant potential for improving the chemotherapeutic efficacy of CPT in cancer treatment.
  • PEPT1 represents a promising target for developing targeted cancer therapies with reduced systemic toxicity.