Designed allosteric biosensors for engineered T cell therapy of cancer

Abstract Adoptive cell therapy with chimeric antigen receptor (CAR) T cells has transformed standard-of-care for selected hematologic malignancies, but relapses are frequent and efficacy against solid tumors remains limited 1,2 . The tumor microenvironment (TME) plays a key role in tumor progression 3 , and both soluble and cellular TME components can limit CAR-T cell function and persistence 4 . Targeting soluble TME factors to enhance anti-tumor responses of engineered T cells through chimeric receptors is not yet broadly explored due to the unpredictable signaling characteristics of synthetic protein receptors. Here we developed a protein design platform for the de novo bottom-up assembly of allosteric receptors with programmable input-output behaviors that respond to soluble TME factors with co-stimulation and cytokine signals in T cells, called T-SenSER ( T ME- sen sing s witch receptor for e nhanced r esponse to tumors). We developed two sets of T-SenSERs targeting vascular endothelial growth factor (VEGF) or colony stimulating factor 1 (CSF1), that are both selectively enriched in a variety of tumors. Combination of CAR and T-SenSER in human T cells enhanced anti-tumor responses in models of lung cancer and multiple myeloma, in a VEGF or CSF1-dependent manner. Our study sets the stage for the accelerated development of synthetic biosensors with custom-built sensing and responses for basic and translational cell engineering applications.