Pretargeted PROTAC Strategy Enables Precise Tumor Target Degradation via Self-Assembling Peptides.

Area of Science:

• Biochemistry
• Molecular Biology
• Nanotechnology

Background:

• Proteolysis-targeting chimeras (PROTACs) degrade proteins but face challenges with poor membrane permeability and off-target toxicity.
• Conventional small-molecule PROTACs exhibit limitations due to their molecular size, hindering effective delivery and potentially causing side effects.

Purpose of the Study:

• To develop a novel peptide-based pretargeted delivery platform for PROTACs to overcome limitations of conventional small-molecule approaches.
• To enhance tumor-targeted delivery and reduce systemic toxicity of PROTACs.

Main Methods:

• A pretargeted system was created using a self-assembling peptide (TPE-GK-N3) targeting integrin αvβ3 and a liposome (DSPE-PEG2000-DBCO) loaded with the PROTAC DT2216.
• A bioorthogonal N3-DBCO click chemistry strategy was employed for membrane-localized liposome recruitment.
• In vitro studies assessed Bcl-xL degradation, cytotoxicity, apoptosis, and cell migration in MDA-MB-231 cells.
• In vivo studies evaluated tumor growth suppression and systemic toxicity.

Main Results:

• The peptide-PROTAC liposome system demonstrated significantly enhanced Bcl-xL degradation, cytotoxicity, apoptosis, and reduced cell migration compared to free DT2216 in vitro.
• In vivo studies showed substantial tumor growth suppression (approximately 65% inhibition) without observable toxicity in normal tissues.
• The pretargeted strategy successfully improved tumor-specific delivery and efficacy of the PROTAC.

Conclusions:

• The developed pretargeted peptide delivery platform effectively overcomes limitations associated with conventional PROTACs.
• This strategy significantly enhances anticancer efficacy while mitigating systemic toxicity, presenting a promising approach for future PROTAC development.
• The study highlights the potential of peptide-based nanomedicine for targeted protein degradation therapies.