Targeted Protein Degradation in Cancer: PROTACs, New Targets, and Clinical Mechanisms

Area of Science:

• Oncology
• Biochemistry
• Drug Discovery

Background:

• Proteolysis targeting chimeras (PROTACs) represent a paradigm shift in targeted cancer therapy, moving beyond traditional occupancy-driven inhibition.
• This heterobifunctional technology harnesses the ubiquitin-proteasome system (UPS) to selectively degrade disease-causing proteins via E3 ubiquitin ligase recruitment.

Purpose of the Study:

• To review the latest advancements in PROTAC design, covering E3 ligase selection, linker chemistry, and ligand optimization.
• To highlight promising preclinical and clinical PROTAC candidates targeting key oncogenic drivers and resistance mechanisms.
• To examine translational challenges and explore emerging solutions for PROTACs in precision oncology.

Main Methods:

• Literature review of recent innovations in PROTAC technology and applications.
• Analysis of PROTAC design principles, including E3 ligase choice and linker strategies.
• Evaluation of preclinical and clinical data for PROTAC candidates and discussion of future modalities.

Main Results:

• PROTACs can catalytically degrade proteins, including previously 'undruggable' targets like transcription factors, at sub-stoichiometric doses.
• Promising candidates are emerging against oncogenic drivers, anti-apoptotic factors (BCL-xL), and nuclear hormone receptors.
• Novel approaches like AUTACs/ATTECs, LYTACs, and AI-driven design are being explored to address translational challenges.

Conclusions:

• PROTACs offer a potent and flexible framework for targeted cancer therapy, overcoming limitations of traditional inhibitors.
• Addressing challenges in pharmacokinetics, off-target effects, and resistance is crucial for clinical translation.
• PROTACs are poised to redefine precision oncology, offering a scalable and robust therapeutic strategy.