A p53-derived apoptotic peptide derepresses p73 to cause tumor regression in vivo

Area of Science:

• Oncology
• Molecular Biology
• Cancer Therapeutics

Background:

• The tumor suppressor p53 is crucial for inducing tumor cell death, but its mutation in many cancers limits therapeutic strategies.
• p53 family members, like p73, are rarely mutated and offer potential therapeutic targets.
• Methods for specifically activating p73 are currently lacking.

Purpose of the Study:

• To identify and characterize a novel therapeutic strategy for activating p73 to induce cancer cell death.
• To investigate the potential of a p53-derived peptide for selective p73 activation and anti-cancer effects.

Main Methods:

• Development of a minimal p53-derived apoptotic peptide.
• Assessment of peptide-induced cell death across various cell types, irrespective of p53 status.
• Investigation of peptide interaction with iASPP, a negative regulator of p53 family members.
• Evaluation of p73 derepression and gene activation in p53-null cells.
• In vivo tumor regression studies using systemic nanoparticle delivery of a peptide-encoding transgene.

Main Results:

• The peptide induced cell death in multiple cell types, independent of p53 status.
• The peptide bound iASPP, a negative regulator of p53 family members.
• In p53-null cells, the peptide derepressed p73, leading to p73-mediated gene activation and cell death.
• Systemic nanoparticle delivery of the peptide-encoding transgene resulted in tumor regression in vivo via p73 activation.

Conclusions:

• This study presents the first strategy for direct and selective therapeutic activation of p73.
• The findings suggest a promising approach for developing broadly applicable anti-cancer agents targeting malignant diseases.
• This peptide-based therapy offers a potential alternative for cancers with p53 mutations.