Estrogen Receptor PROTAC Composition for Mutant-Resistant Degradation
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Solution Overview
Problem
Current endocrine therapies for estrogen receptor (ER) positive breast cancer face limitations such as restricted applicability, ineffectiveness against mutant variants, and significant side effects, necessitating the development of safer and more effective treatment approaches.
Innovation Solution
Development of a novel PROTAC compound targeting the estrogen receptor, represented by specific chemical formulas, which induces the degradation of ER through the ubiquitin-proteasome system, forming a stable ternary complex with the target protein and E3 ubiquitin ligase to degrade ER without requiring high binding affinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional small molecule inhibitors are used to occupy the active site of estrogen receptor, then the target protein function can be inhibited, but high concentrations are required which increases toxicity and side effects
Solution Approach 1:
The PROTAC molecule is segmented into three functional parts: a target protein ligand (estrogen receptor binder), a linker, and an E3 ubiquitin ligase ligand. This segmentation allows the molecule to simultaneously bind the target protein and recruit the degradation machinery, achieving protein degradation at lower concentrations without requiring high occupancy of the target's active site, thereby reducing toxicity and side effects
Solution Approach 2:
The PROTAC acts as an intermediary molecule that mediates the interaction between the target protein (estrogen receptor) and the E3 ubiquitin ligase. By forming a ternary complex, it enables the ubiquitination and subsequent degradation of the target protein through the proteasome system, achieving therapeutic effects at lower doses compared to traditional inhibitors
2Adaptability or versatility
If traditional small molecule inhibitors are used to block downstream signal transduction pathways, then therapeutic effects can be achieved, but the approach is ineffective against mutant variants and has restricted applicability
Solution Approach 1:
Instead of trying to inhibit the function of the target protein (estrogen receptor) through active site occupancy, the PROTAC approach inverts the strategy by recruiting the protein's natural degradation machinery (ubiquitin-proteasome system) to eliminate the protein entirely. This inversion allows the approach to work against mutant variants that may have altered active sites but retain the ability to be recognized by the PROTAC and degraded through the ubiquitin system
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 PROTAC compound effectively degrades ER, inhibiting tumor growth and proliferation, demonstrating favorable antitumor activity with a favorable safety profile, potentially overcoming resistance to endocrine therapy and reducing side effects.
Implementation Method 1
PROTAC is a bifunctional molecule composed of two small molecule ligands, typically consisting of three parts: a targeting protein ligand, an E3 ubiquitin ligase ligand, and a suitable length of linker, which are connected together. Once the PROTAC molecule enters the cell, the protein-targeting ligand at one end of its structure its structure can specifically bind to the target protein, while the E3 ubiquitin ligase (such as cereblon, CRBN) ligand at the other end can recruit E3 ligase, thereby forming a stable target protein-PROTAC-E3 ubiquitin ligase ternary complex. After labeling the target protein with ubiquitination, the ubiquitinated protein can be recognized and degraded by the proteasome 26S inside the cell.
Data Source
Figure 1A~1C
Figure 1D~2A
Figure 2B~2D
AI summary
Provided are a PROTAC compound targeting the hydrolysis of an estrogen receptor (ER) protein and a use thereof.