Proteasome Inhibitor Warhead Design to Overcome Drug Resistance
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Solution Overview
Problem
Current proteasome inhibitors, such as Velcade®, Kyprolis®, and Ninlaro®, are not curative and face resistance issues, necessitating new compounds that can effectively inhibit constitutive and immunoproteasomes, exhibit good oral absorption, metabolic stability, and have a favorable pharmacokinetic profile without toxicity or significant side effects.
Innovation Solution
Development of novel compounds of formula I, which include a peptidic group binding to the proteasome's proteolytic site, forming an epoxide ring with R 2 and R 3, and a group like pyridine to interact with Tyr-169 or Ser-21, providing selective inhibition of β5c or β1i subunits, and potentially interacting with other catalytic subunits through π-π interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional proteasome inhibitors (Velcade®, Kyprolis®, Ninlaro®) are used, then proteasome inhibition is achieved, but resistance develops and curative effect is not obtained
Solution Approach 1:
The invention modifies the chemical structure of proteasome inhibitors by changing the warhead group from conventional epoxyketone to novel oxazepane ring structure, and by modifying peptidic side chains to achieve different binding modes and overcome resistance mechanisms that developed against previous generation inhibitors
Solution Approach 2:
The compounds combine multiple functional elements: a core oxazepane ring structure for covalent binding to catalytic threonine, peptidic side chains for binding to substrate recognition pockets, and additional aromatic or heterocyclic groups for occupying new sites and forming π-π interactions, creating a multi-component inhibitor that achieves superior efficacy and reduced resistance
2Reliability
If proteasome inhibitors are designed for high activity, then nanomolar inhibition is achieved, but selectivity between subunits must be maintained
Solution Approach 1:
The invention designs different peptidic side chains with specific local properties (aromatic rings, hydrogen bond donors/acceptors, basic amino acids) that interact with specific subunit characteristics (Tyr-169 in β5c, Ser-21 in β1i), enabling high activity against target subunits while maintaining selectivity through localized molecular recognition events
Solution Approach 2:
The inhibitor is segmented into distinct functional domains: the oxazepane warhead for covalent attachment, peptidic segments for binding to S1-S3 pockets, and terminal aromatic/heterocyclic groups for occupying new sites and forming π-π interactions, allowing independent optimization of each segment for both activity and selectivity
3Reliability
If peptidic groups are used for binding, then proteolytic site attachment is achieved, but oral absorption and metabolic stability must be improved
Solution Approach 1:
The invention changes the chemical parameters of the peptidic moiety by incorporating non-natural amino acids, cyclic structures, and lipophilic aromatic groups that maintain proteolytic site binding affinity while improving membrane permeability and resistance to metabolic degradation, thereby enhancing oral bioavailability
Solution Approach 2:
The peptidic side chains act as intermediaries that mediate between the covalent oxazepane core and the proteolytic site, providing necessary binding affinity while their specific chemical composition (amino acid sequence, modifications) serves as a bridge to achieve both biological activity and pharmacokinetic properties
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 compounds demonstrate nanomolar activity against proteasome subunits, forming a unique 1,4-oxazepane ring structure, offering potential as effective antineoplastic agents with improved selectivity and reduced resistance, suitable for treating cancers and autoimmune diseases.
Implementation Method 1
The inhibitory mode of action of epoxyketone inhibitors, such as epoxomicin, carfilzomib or dihydroeponemycin has been described based on several crystal structures with human 20S proteasome. The gamma-hydroxyl group of the catalytic threonine Thr-1 reacts with the ketone group, and the amino group of the Thr-1 reacts with the terminal carbon atom of the epoxide. This results in the formation of an oxazepane ring product
Implementation Method 2
R 5 is a group occupying the new site binding, particularly an alkyl, aryl or heteroaryl group to establish pi-pi interactions with Tyr-169
Data Source
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AI summary
Proteasome inhibitors of formula I, wherein the meanings for the various substituents are as disclosed in the description. The warhead is extended with a moiety facilitating pi-pi-interaction with Tyr169