A conformation-specific ON-switch for controlling CAR T cells with an orally available drug

Molecular ON-switches in which a chemical compound induces protein–protein interactions can allow cellular function to be controlled with small molecules. ON-switches based on clinically applicable compounds and human proteins would greatly facilitate their therapeutic use. Here, we developed an ON-...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2020-06, Vol.117 (26), p.14926-14935
Main Authors: Zajc, Charlotte U., Dobersberger, Markus, Schaffner, Irene, Mlynek, Georg, Pühringer, Dominic, Salzer, Benjamin, Djinović-Carugo, Kristina, Steinberger, Peter, De Sousa Linhares, Annika, Yang, Nicole J., Obinger, Christian, Holter, Wolfgang, Traxlmayr, Michael W., Lehner, Manfred
Format: Article
Language:English
Subjects:
Binders
Biological Sciences
Change detection
Chemical compounds
Crystal structure
Lipocalin
Lymphocytes
Lymphocytes T
Molecular structure
Protein interaction
Proteins
Switches
Vitamin A
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Summary:Molecular ON-switches in which a chemical compound induces protein–protein interactions can allow cellular function to be controlled with small molecules. ON-switches based on clinically applicable compounds and human proteins would greatly facilitate their therapeutic use. Here, we developed an ON-switch system in which the human retinol binding protein 4 (hRBP4) of the lipocalin family interacts with engineered hRBP4 binders in a small molecule-dependent manner. Two different protein scaffolds were engineered to bind to hRBP4 when loaded with the orally available small molecule A1120. The crystal structure of an assembled ON-switch shows that the engineered binder specifically recognizes the conformational changes induced by A1120 in two loop regions of hRBP4. We demonstrate that this conformation-specific ON-switch is highly dependent on the presence of A1120, as demonstrated by an ∼500-fold increase in affinity upon addition of the small molecule drug. Furthermore, the ON-switch successfully regulated the activity of primary human CAR T cells in vitro. We anticipate that lipocalin-based ON-switches have the potential to be broadly applied for the safe pharmacological control of cellular therapeutics.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.1911154117