Bio-Layer Interferometry as a strategic platform to validate covalent "proximity inducing" small molecules with synthetic tumor Immunotherapeutic applications

The host immune "recognition" of cancer forms the basis of modern tumor immmunotherapy, a highly targeted treatment option with the demonstrated ability to "cure" previously lethal blood cancers. Immune recognition is mimimally governed by the proximity of "active" phagocytic and cytotoxic immune cells to the site of target cancer cells. To probe mechanistic aspects of the recognition process, generate useful immunotherapeutic design principles, and design potentially new classes of "reactive" synthetic tumor immunotherapeutics, our lab develops chemical tools that modulate the proximity of host immune cells with cancer cells. One class of these chemical tools we call "covalent immune recruiters" or CIRs, function by binding and forming selective irreversible linkages to tumor antigens highly expressed on the cancer cell surface, and or natural immune machinery e.g. serum antibodies, Fc receptors. In vitro validation of CIR function is thus highly non-trivial as both binding affinities and covalent reaction kinetics must be characterized and differentiated in the context of two different proteins.

 

This seminar focuses on the unique suitability and application of BLI for the characterization of CIR function at the molecular level. We demonstrate BLI can be employed to efficiently characterize CIR binding affinities against both prostate tumor antigen and human serum antibody proteins, and selective covalent recruitment of these antibodies to the tumor antigen. The elucidation of these highly relevant physical parameters via other conventional techniques such as ITC and fluorescent polarization is difficult if not impossible largely due to higher sample concentration and time requirements, in addition to aggregation induced artifacts. Taken together, BLI validation of CIRs can accelerate lead compound advancement to in vivo validation studies with additional utility in characterizing emerging classes of covalent inhibitor drugs and ABPP chemical tools.

 

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