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Published on: November 9, 2020
Harnessing the E3 Ligase KEAP1 for Targeted Protein Degradation
Jieli Wei1, Fanye Meng1, Kwang-Su Park1
1Mount Sinai Center for Therapeutics Discovery, Departments of Pharmacological Sciences and Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States.
This study introduces a novel Proteolysis Targeting Chimera (PROTAC) using the KEAP1 E3 ligase for targeted protein degradation. The new PROTAC, MS83, effectively degrades BRD4 and BRD3 proteins with enhanced durability and antiproliferative activity.
Area of Science:
- Biochemistry
- Molecular Biology
- Drug Discovery
Background:
- Proteolysis Targeting Chimeras (PROTACs) are an emerging therapeutic strategy.
- PROTACs utilize the ubiquitin-proteasome system (UPS) for targeted protein degradation.
- Limited E3 ligases are currently utilized in PROTAC development.
Purpose of the Study:
- To investigate the potential of KEAP1 E3 ligase in PROTAC-mediated protein degradation.
- To develop and characterize a novel PROTAC (MS83) targeting BRD4/3/2 utilizing KEAP1.
- To evaluate the efficacy, durability, and antiproliferative activity of MS83 compared to existing PROTACs.
Main Methods:
- Design and synthesis of a PROTAC (MS83) by linking a KEAP1 ligand to a BRD4/3/2 binder.
- Cell-based assays to assess protein degradation, including concentration, time, KEAP1, and UPS dependency.
- Comparison of MS83 with a CRBN-recruiting PROTAC (dBET1) regarding degradation kinetics and antiproliferative effects.
- Isoform-specific degradation analysis of BRD4.
Main Results:
- MS83 effectively reduced BRD4 and BRD3 protein levels in a KEAP1- and UPS-dependent manner.
- MS83 demonstrated more durable degradation of BRD4/3 compared to dBET1 in MDA-MB-468 cells.
- Selective degradation of the short isoform of BRD4 over the long isoform was observed in MDA-MB-231 cells.
- MS83 exhibited superior antiproliferative activity compared to dBET1.
Conclusions:
- The KEAP1 E3 ligase can be successfully harnessed for targeted protein degradation.
- MS83 represents a potent and selective PROTAC with improved properties over existing agents.
- This work expands the E3 ligase repertoire for PROTAC development, offering new therapeutic possibilities.
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