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Rapid induction of apoptosis mediated by peptides that bind initiation factor eIF4E

T P Herbert1, R Fåhraeus, A Prescott

  • 1Department of Anatomy and Physiology, MSI/WTB Complex, University of Dundee, UK. t.p.herbert@dundee.ac.uk

Current Biology : CB
|July 19, 2000
PubMed

Insights

Overexpression of eukaryotic initiation factor 4E (eIF4E) drives cancer. Novel peptides targeting eIF4E induce apoptosis, revealing a direct role for eIF4E in cell survival independent of translation.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Cancer Research

Background:

  • Overexpression of eukaryotic initiation factor 4E (eIF4E) promotes cell transformation and is implicated in human cancers.
  • eIF4E availability regulates mRNA translation and cell growth by forming initiation complexes with eIF4G.
  • eIF4E-binding proteins (4E-BPs) inhibit eIF4E availability, and their overexpression can reverse eIF4E-induced cell transformation.

Purpose of the Study:

  • To investigate the role of eIF4E in cell transformation using novel peptide inhibitors.
  • To explore the mechanism by which eIF4E influences cell survival and apoptosis.

Main Methods:

  • Development of peptides mimicking eIF4E-binding motifs from 4E-BPs and eIF4G, linked to a cell-penetrating sequence.
  • Introduction of these peptides into MRC5 cells to observe effects on cell viability and apoptosis.
  • Site-directed mutagenesis (alanine substitutions) to assess the importance of eIF4E binding for peptide activity.

Main Results:

  • Peptides designed to bind eIF4E induced rapid, dose-dependent apoptosis in MRC5 cells.
  • Alanine substitutions impairing eIF4E binding significantly reduced the apoptotic effect.
  • A peptide with abolished eIF4E binding failed to induce apoptosis, confirming eIF4E binding as the mechanism.
  • Apoptosis induction was independent of protein synthesis inhibition.

Conclusions:

  • The study demonstrates that eIF4E plays a direct role in promoting cell survival.
  • This pro-survival role of eIF4E is distinct from its established function in mRNA translation.
  • Targeting eIF4E with specific peptides represents a potential therapeutic strategy for cancers associated with eIF4E overexpression.

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