CRISPR/Cas9-mediated PD-1 disruption enhances anti-tumor efficacy of human chimeric antigen receptor T cells

Sci Rep. 2017 Apr 7;7(1):737. doi: 10.1038/s41598-017-00462-8.


Immunotherapies with chimeric antigen receptor (CAR) T cells and checkpoint inhibitors (including antibodies that antagonize programmed cell death protein 1 [PD-1]) have both opened new avenues for cancer treatment, but the clinical potential of combined disruption of inhibitory checkpoints and CAR T cell therapy remains incompletely explored. Here we show that programmed death ligand 1 (PD-L1) expression on tumor cells can render human CAR T cells (anti-CD19 4-1BBζ) hypo-functional, resulting in impaired tumor clearance in a sub-cutaneous xenograft model. To overcome this suppressed anti-tumor response, we developed a protocol for combined Cas9 ribonucleoprotein (Cas9 RNP)-mediated gene editing and lentiviral transduction to generate PD-1 deficient anti-CD19 CAR T cells. Pdcd1 (PD-1) disruption augmented CAR T cell mediated killing of tumor cells in vitro and enhanced clearance of PD-L1+ tumor xenografts in vivo. This study demonstrates improved therapeutic efficacy of Cas9-edited CAR T cells and highlights the potential of precision genome engineering to enhance next-generation cell therapies.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, CD19 / genetics
  • Antigens, CD19 / immunology
  • Antigens, Neoplasm / genetics
  • Antigens, Neoplasm / immunology
  • B7-H1 Antigen / metabolism
  • Biomarkers
  • CRISPR-Cas Systems*
  • Cell Line, Tumor
  • Female
  • Gene Expression
  • Gene Knockdown Techniques
  • Gene Targeting*
  • Humans
  • Immunophenotyping
  • Mice
  • Mice, Knockout
  • Neoplasms / genetics*
  • Neoplasms / immunology*
  • Neoplasms / pathology
  • Neoplasms / therapy
  • Programmed Cell Death 1 Receptor / genetics*
  • Programmed Cell Death 1 Receptor / metabolism
  • Receptors, Antigen, T-Cell / genetics*
  • Receptors, Antigen, T-Cell / metabolism*
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism*


  • Antigens, CD19
  • Antigens, Neoplasm
  • B7-H1 Antigen
  • Biomarkers
  • CD274 protein, human
  • PDCD1 protein, human
  • Programmed Cell Death 1 Receptor
  • Receptors, Antigen, T-Cell