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p28, an anionic cell-penetrating peptide, increases the activity of wild type and mutated p53 without altering its

Tohru Yamada1, Tapas K Das Gupta, Craig W Beattie

  • 1Department of Surgery, Division of Surgical Oncology, University of Illinois at Chicago College of Medicine, 840 South Wood Street, Suite 618, Chicago, Illinois 60612, United States.

Molecular Pharmaceutics
|August 20, 2013
PubMed

Insights

The peptide p28 increases levels of wild type and mutant p53, inhibiting cancer cell proliferation. It activates p53 by reducing COP1 levels, even with p53 mutations affecting the DNA binding domain.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Drug Discovery

Background:

  • p53 is a tumor suppressor protein crucial for cell cycle regulation.
  • Cancer cells often harbor p53 mutations, leading to uncontrolled proliferation.
  • Targeting p53 pathways remains a key strategy in cancer therapy.

Purpose of the Study:

  • To investigate the mechanism by which the cell-penetrating peptide p28 modulates p53 activity.
  • To determine if p28 can activate p53 in the presence of common p53 mutations.
  • To explore p28 as a potential therapeutic agent for various cancers.

Main Methods:

  • Binding assays to assess p28 interaction with the p53 DNA binding domain (DBD).
  • Cell-based assays measuring intracellular p53 levels and cell proliferation.
  • Western blotting to analyze protein levels, including p53 and the E3 ligase COP1.
  • Conformational analysis of p53 in response to p28 treatment.

Main Results:

  • p28 binds to the p53 DBD, increasing intracellular wild-type and mutant p53 levels.
  • p28 treatment inhibits cancer cell proliferation by activating p53-mediated pathways.
  • p53 activation by p28 occurs even when mutations affect DNA contact or DBD structure.
  • p28 treatment leads to reduced COP1 levels without altering p53 conformation.
  • p28's mechanism involves inhibiting COP1 binding to p53.

Conclusions:

  • p28 effectively increases p53 activity and inhibits cancer cell growth.
  • p28 demonstrates potential for therapeutic application across a spectrum of p53 mutations.
  • The inhibition of COP1 binding by p28 is a key mechanism for p53 activation.

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