BCKDK Modification Enhances the Anticancer Efficacy of CAR-T Cells by Reprogramming Branched Chain Amino Acid Metabolism

Altered Branched Chain Amino Acids (BCAA), including leucine, isoleucine and valine, are frequently observed in patients with advanced cancer. We evaluated the efficacy of Chimeric Antigen Receptor (CAR) T cell-mediated cancer cell lysis potential in the immune microenvironment of BCAA supplementation and deletion. BCAA supplementation increased cancer cell killing percentage, while accelerating BCAA catabolism and deceasing BCAA transporter decreased cancer cell lysis efficacy. We thus designed BCKDK engineering CAR T cells for the reprogramming of BCAA metabolism in the tumor microenvironment based on the genotype and phenotype modification. BCKDK overexpression (OE) in CAR-T cells significantly improved cancer cell lysis, while BCKDK knockout (KO) resulted in inferior lysis potential. In an in vivo experiment, BCKDK-OE CAR-T cells treatment significantly prolonged the survival of mice bearing NALM6-GL cancer cells, with the differentiation of central memory cells and the increasing proportion of CAR-T cells in peripheral circulation. BCKDK-KO CAR-T cells treatment resulted in shorter survival and decreasing percentage of CAR-T cells in peripheral circulation. In conclusion, BCKDK engineered CAR-T cells exert distinct phenotype for the superior anticancer efficiency.