Engineering amino acid uptake or catabolism promotes CAR T-cell adaption to the tumor environment

Abstract

Cancer cells take up amino acids from the extracellular space to drive cell proliferation and viability. Similar mechanisms are employed by immune cells. The result is competition between conventional T cells, or indeed CAR-T cells, and tumour cells for limited availability of amino acids within the environment. We demonstrate that T cells can be re-engineered to express SLC7A5 or SLC7A11 transmembrane amino acid transporters alongside chimeric antigen receptors (CAR). Transporter modifications increase CAR-T cell proliferation under low tryptophan or cystine conditions with no loss of CAR cytotoxicity or increased exhaustion. Transcriptomic and phenotypic analysis reveals that downstream, SLC7A5/SLC7A11 modified CAR-T cells upregulate intracellular Arginase expression and activity. In turn we engineer and phenotype a further generation of CAR-T cells which express functional Arginase I/Arginase II enzymes, and have enhanced CAR-T cell proliferation and anti-tumour activity. Thus CAR-T cells can be adapted to the amino acid metabolic microenvironment of cancer, a hitherto recognised but unaddressed barrier to successful CAR-T therapy.

Metabolic plasticity of T cell fate decision

“…Overexpression of the amino acid transporters SLC7A5 or SLC7A11 in CAR-T cells can enhance arginase amino acid uptake and boost T cell proliferation and anti-tumor activity. [151] Moreover, elevated PGC-1α expression in CD8 + T cells can increase mitochondrial biogenesis and tness, consequently inhibiting the exhaustion progression of TILs. [4,69] Additionally, tumor-speci c CD8 + T cells can also be metabolically reprogrammed to enhance effector functions by increasing phosphoenolpyruvate production through the overexpression of PCK1.…”

Analyzing the impact of metabolism on immune cells in tumor microenvironment to promote the development of immunotherapy

“…So the proliferation and activation of T cells are hindered, especially effector T cells. Besides, the lack of tryptophan or cysteine inhibits the proliferation of T cells and affects the role of T cells ( 75 ). Moreover, CD8+T cells lose the expression of the mechanistic target of rapamycin (mTOR) due to the deficiency of RagD-dependent amino acids in TME.…”

“…The growth of multiple T cells is connected with the amount of amino acids. Promoting the inflow of amino acids is conducive to the growth of T cells and eventually affects the anti-tumor immune response ( 75 ). Besides, it is indicated that the function of effector T cells can be improved by supplementing amino acids, and anti-tumor immunity can be enhanced when anti-PD-L1 antibody therapy is performed at the same time ( 5 ).…”

Metabolic dialogues: regulators of chimeric antigen receptor T cell function in the tumor microenvironment

“…To overcome arginine depletion, Mussai, De Santo and colleagues ectopically expressed enzymes involved in either arginine catabolism (ARG1/ARG2) or arginine resynthesis [arginosuccinate synthase (ASS) and ornithine transcarbamylase (OTC)] in CD33‐ as well as GD2‐targeted CAR T cells. They found that these modified CAR T cells exhibited enhanced in vivo anti‐tumor responses against human AML and neuroblastoma [ 213 , 214 ]. Similarly, our group and others have modulated the expression of glucose, glutamine, and arginine transporters, among others, in order to enhance CAR T cell function in nutrient‐deprived tumor microenvironments (Fig.…”