Trivalent PROTACs for Selective BRD2 Degradation
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Solution Overview
Problem
Designing PROTACs that efficiently target and degrade Bromo- and Extra-Terminal (BET) family proteins, such as BRD2, BRD3, and BRD4, is challenging due to the limitations of conventional monovalent PROTACs in forming stable and cooperative ternary complexes, leading to incomplete and slow target degradation.
Innovation Solution
Development of trivalent PROTACs that combine a bivalent target ligand with an E3 ubiquitin ligase recruitment component, enhancing avidity and cooperativity through a specific chemical structure that binds to BET family proteins, particularly BRD2, BRD3, and BRD4, to induce their selective degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If monovalent PROTACs are used to target BET family proteins, then the design is simpler, but the formation of stable ternary complexes is insufficient leading to slow and incomplete target degradation
Solution Approach 1:
The PROTAC molecule is segmented into three distinct functional components: a first ligand that binds to the target protein (BET family member), a second ligand that binds to the E3 ubiquitin ligase, and a linker that connects these two ligands. This segmentation allows each component to be optimized independently for its specific binding function, thereby forming stable ternary complexes that enable efficient target degradation while maintaining manageable design complexity through modular assembly.
2Ease of manufacture
If conventional PROTAC designs are used, then the synthesis process is simpler, but extensive chemical optimization is still required to achieve effective degradation
Solution Approach 1:
The patent employs universal E3 ligase binding ligands (such as those targeting VHL or CRBN) that can be paired with various target-specific first ligands. This multi-functionality approach allows the same E3 ligase binding module to be reused across different PROTAC designs targeting various BET family members, thereby simplifying the synthesis process by reducing the number of unique molecular entities that need to be manufactured while maintaining high degradation efficacy through standardized optimization protocols.
3Device complexity
If monovalent PROTACs bind to target proteins, then the binding mechanism is simpler, but the cooperativity and avidity are insufficient for productive ternary complex formation
Solution Approach 1:
The patent merges two separate binding interactions into a single integrated PROTAC molecule: the first ligand binds to the target protein while the second ligand simultaneously binds to the E3 ubiquitin ligase. This merging of binding functions into one molecular entity ensures that both interactions occur with high affinity and cooperativity, forming stable ternary complexes that reliably position the target protein for ubiquitination and degradation, thereby enhancing complex stability without excessive mechanism complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The trivalent PROTACs demonstrate potent and selective degradation of BRD2 over BRD3 and BRD4, with rapid and complete degradation at low concentrations, minimizing the 'hook effect' and achieving significant therapeutic efficacy in cancer and inflammatory diseases.
Implementation Method 1
a bivalent target ligand with an E3 ubiquitin ligase recruitment component, enhancing avidity and cooperativity through a specific chemical structure that binds to BET family proteins
Implementation Method 2
Degraders form a ternary complex, bringing together the target protein and an E3 ubiquitin ligase component, resulting in ubiquitination and subsequent degradation of the target protein via the proteasome
Implementation Method 3
ubiquitination and subsequent degradation of the target protein via the proteasome
Data Source
AI summary
This invention particularly relates to trifunctional PROTACs of formula I as described herein which bind to a protein within the Bromo- and Extra-Terminal (BET) family of proteins, and especially to PROTACs including small molecule E3 ubiquitin ligase protein binding ligand compounds which induce preferential degradation of the BRD2 protein within the bromodomain of the BET family of proteins.