CRISPR/Cas9-mediated PD-1 disruption enhances human mesothelin-targeted CAR T cell effector functions

Cancer Immunol Immunother. 2019 Mar;68(3):365-377. doi: 10.1007/s00262-018-2281-2. Epub 2018 Dec 6.

Abstract

The interaction between programmed cell death protein 1 (PD-1) on activated T cells and its ligands on a target tumour may limit the capacity of chimeric antigen receptor (CAR) T cells to eradicate solid tumours. PD-1 blockade could potentially enhance CAR T cell function. Here, we show that mesothelin is overexpressed in human triple-negative breast cancer cells and can be targeted by CAR T cells. To overcome the suppressive effect of PD-1 on CAR T cells, we utilized CRISPR/Cas9 ribonucleoprotein-mediated editing to disrupt the programmed cell death-1 (PD-1) gene locus in human primary T cells, resulting in a significantly reduced PD-1hi population. This reduction had little effect on CAR T cell proliferation but strongly augmented CAR T cell cytokine production and cytotoxicity towards PD-L1-expressing cancer cells in vitro. CAR T cells with PD-1 disruption show enhanced tumour control and relapse prevention in vivo when compared with CAR T cells with or without αPD-1 antibody blockade. Our study demonstrates a potential advantage of integrated immune checkpoint blockade with CAR T cells in controlling solid tumours and provides an alternative CAR T cell strategy for adoptive transfer therapy.

Keywords: Chimeric antigen receptor; Mesothelin; Programmed cell death protein 1; SgRNA-guided clustered regularly interspaced short palindrome repeats-associated nuclease Cas9.

MeSH terms

  • Animals
  • CRISPR-Cas Systems / physiology*
  • Cell Line, Tumor
  • Cytotoxicity, Immunologic
  • GPI-Linked Proteins / genetics*
  • Humans
  • Immunotherapy, Adoptive
  • Lymphocyte Activation
  • Mesothelin
  • Mice
  • Neoplasms, Experimental / therapy
  • Programmed Cell Death 1 Receptor / antagonists & inhibitors
  • Programmed Cell Death 1 Receptor / genetics*
  • Receptors, Antigen, T-Cell / genetics*
  • Receptors, Antigen, T-Cell / immunology

Substances

  • GPI-Linked Proteins
  • Msln protein, mouse
  • Programmed Cell Death 1 Receptor
  • Receptors, Antigen, T-Cell
  • Mesothelin