Selective SMARCA2 PROTAC Degraders via Linker Asymmetry
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Solution Overview
Problem
Current therapies for cancers with mutations in SMARCA2 or SMARCA4 are limited in selectivity and efficacy, as they often target both ATPases non-selectively, leading to potential off-target effects and reduced therapeutic benefit.
Innovation Solution
Development of compounds of formula (I) and (III) that act as selective binders or degraders of SMARCA2 over SMARCA4, utilizing specific structural features to target SMARCA2 for degradation while sparing SMARCA4, thereby offering a more targeted approach to treating cancers characterized by SMARCA2 mutations or overexpression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PROTACs are used to degrade SMARCA2 and SMARCA4, then protein degradation efficacy is improved, but selectivity between SMARCA2 and SMARCA4 deteriorates
Solution Approach 1:
The patent introduces selective linkers with specific chemical structures (e.g., amide bonds, ester bonds, carbamate bonds) that create local chemical environments favoring binding to SMARCA2 over SMARCA4. The linker contains functional groups that form preferential interactions with residues unique to SMARCA2, thereby achieving selectivity while maintaining degradation efficacy
Solution Approach 2:
The PROTAC molecules are designed with asymmetric structures where the distance and orientation between the SMARCA2-binding domain and the E3 ligase-binding domain are optimized for SMARCA2 degradation. The linker length and configuration create an asymmetric ternary complex geometry that favors SMARCA2 over SMARCA4, enabling selective degradation
2Adaptability or versatility
If PROTACs with long linkers are used, then binding flexibility is improved, but molecular complexity increases
Solution Approach 1:
The linker is segmented into modular units with defined chemical structures (e.g., PEG chains, amino acid sequences, or flexible hydrocarbon chains) that can be independently optimized. This segmentation allows systematic tuning of linker length and flexibility while maintaining synthetic feasibility and reducing overall molecular complexity
Solution Approach 2:
The patent systematically varies linker parameters such as length (number of atoms), flexibility (rotational freedom), and chemical composition to optimize binding while controlling complexity. Specific parameter ranges are established (e.g., linker length of 5-20 atoms) to balance flexibility needs with synthetic tractability and selectivity requirements
Data Source
AI summary
The present invention encompasses compounds of formula (I), wherein the groups A, R1, R3 and R4 have the meanings given in the claims and specification, proteolysis targeting chimera (PROTACs) comprising such compounds of formula (I), their use as degraders of SMARCA, pharmaceutical compositions which contain PROTACs of this kind and their medical uses, especially as agents for treatment and/or prevention of oncological diseases.