Conditionally Active CARs for Selective Tumor Targeting
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Solution Overview
Problem
Current methods struggle to engineer proteins that are virtually inactive at normal physiological conditions but active at aberrant conditions, maintaining or exceeding wild-type activity levels, especially for chimeric antigen receptors used in cancer therapy.
Innovation Solution
Development of conditionally active chimeric antigen receptors with antigen-specific targeting regions evolved from parent proteins, featuring a decrease in activity at normal physiological conditions and an increase in activity at aberrant conditions, incorporating a transmembrane domain and intracellular signaling domain, along with optional extracellular spacer and co-stimulatory domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If destabilizing mutations are introduced to inactivate protein at normal physiological conditions, then activity at normal conditions decreases, but activity at aberrant conditions may be reduced below desired levels
Solution Approach 1:
The patent applies parameter changes by introducing specific destabilizing mutations that alter the protein's stability parameters. These mutations are carefully selected to reduce activity at normal physiological conditions (pH 7.4, 37°C) while preserving or enhancing activity at aberrant conditions (acidic pH, elevated temperature). The mutations change the protein's conformational equilibrium and stability profile without completely abolishing its functional capability under stress conditions.
Solution Approach 2:
The patent applies local quality by introducing destabilizing mutations at specific localized regions of the protein structure rather than globally affecting the entire protein. This allows selective destabilization of certain domains or regions that are critical for normal-condition activity, while preserving the core functional regions needed for aberrant-condition activity. The mutations are positioned to create local conformational changes that selectively impact activity under different conditions.
2Productivity
If activity-increasing mutations are combined with destabilizing mutations, then activity at aberrant conditions improves, but the destabilizing effect may counteract the activity improvement
Solution Approach 1:
The patent applies dynamics by creating a protein that dynamically adapts its conformational state based on environmental conditions. The combination of destabilizing and activity-increasing mutations generates a protein that exists in different conformational equilibria under normal versus aberrant conditions. At normal conditions, the protein favors an inactive conformation, while at aberrant conditions, the equilibrium shifts toward the active conformation, allowing the protein to respond dynamically to environmental stress.
Solution Approach 2:
The patent applies composite materials by combining multiple mutation types (destabilizing and activity-increasing) within the same protein sequence to create a composite functional profile. The destabilizing mutations contribute the property of conditional inactivation, while the activity-increasing mutations contribute enhanced catalytic efficiency or binding affinity. The resulting chimeric protein integrates these complementary properties to achieve selectivity at normal conditions while maintaining high activity at aberrant conditions.
3Reliability
If protein is engineered to be virtually inactive at normal physiological conditions, then selectivity improves, but overall activity level may fall below therapeutic threshold
Solution Approach 1:
The patent applies periodic action by engineering the protein to be periodically activated based on environmental cues. The protein cycles between inactive (at normal physiological conditions) and active (at aberrant conditions) states, with the activation being triggered by periodic exposure to disease-site conditions such as acidic pH or elevated temperature. This periodic activation pattern ensures that the protein accumulates in an inactive state during circulation but becomes actively therapeutic when encountering the target disease microenvironment.
Data Source
AI summary
This disclosure relates to a chimeric antigen receptor for binding with a tumor specific target antigen. The chimeric antigen receptor comprises at least one antigen specific targeting region evolved from a parent protein or a fragment thereof and having a decrease in activity in the assay at the normal physiological condition compared to the activity in the assay under the aberrant condition. A method for producing the chimeric antigen receptor is also provided.