Project description:Chimeric antigen receptor (CAR)-T cells are powerful therapeutics; however, their efficacy is often hindered by critical hurdles. Here utilizing the endocytic feature of the cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) cytoplasmic tail, we reprogram CAR function and substantially enhance CAR-T efficacy in vivo. CAR-T cells with monomeric, duplex or triplex CTLA-4 cytoplasmic tails (CCTs) fused to the C terminus of CAR exhibit a progressive increase in cytotoxicity under repeated stimulation, accompanied by reduced activation and production of proinflammatory cytokines. Further characterization reveals that CARs with increasing CCT fusion show a progressively lower surface expression, regulated by their constant endocytosis, recycling and degradation under steady state. The molecular dynamics of reengineered CAR with CCT fusion results in reduced CAR-mediated trogocytosis, loss of tumor antigen and improved CAR-T survival. CARs with either monomeric (CAR-1CCT) or duplex CCTs (CAR-2CCT) have superior antitumor efficacy in a relapsed leukemia model. Single-cell RNA sequencing and flow cytometry analysis reveal that CAR-2CCT cells retain a stronger central memory phenotype and exhibit increased persistence. These findings illuminate a unique strategy for engineering therapeutic T cells and improving CAR-T function through synthetic CCT fusion, which is orthogonal to other cell engineering techniques.
Project description:To gain further insight into how CCT fusion engineering impacts their function, we characterized CAR-T cells using transcriptome profiling. We performed mRNA-seq from all four groups of CAR-T cells, either without stimulation (baseline) or with 2 rounds of NALM6GL stimulation. For CAR-T cells that were cocultured with 2 rounds of NALM6GL cells, we sorted the pure CAR-T populations (CAR+; GFP-) before subjecting them to RNA sequencing
Project description:To systematically investigate the effect of CCT engineering on CAR-T cell phenotypes in vivo, we used single-cell RNA sequencing (scRNA-seq) to characterize the full spectrum of engineered CAR-T cells and their transcriptomic profiles
