Chimeric antigen receptor engineered NK cellular immunotherapy overcomes the selection of T-cell escape variant cancer cells

J Immunother Cancer. 2021 Mar;9(3):e002128. doi: 10.1136/jitc-2020-002128.


Background: As heterogeneous tumors develop in the face of intact immunity, tumor cells harboring genomic or expression defects that favor evasion from T-cell detection or elimination are selected. For patients with such tumors, T cell-based immunotherapy alone infrequently results in durable tumor control.

Methods: Here, we developed experimental models to study mechanisms of T-cell escape and demonstrated that resistance to T-cell killing can be overcome by the addition of natural killer (NK) cells engineered to express a chimeric antigen receptor (CAR) targeting programmed death ligand-1 (PD-L1).

Results: In engineered models of tumor heterogeneity, PD-L1 CAR-engineered NK cells (PD-L1 t-haNKs) prevented the clonal selection of T cell-resistant tumor cells observed with T-cell treatment alone in multiple models. Treatment of heterogenous cancer cell populations with T cells resulted in interferon gamma (IFN-γ) release and subsequent upregulation of PD-L1 on tumor cells that escaped T-cell killing through defects in antigen processing and presentation, priming escape cell populations for PD-L1 dependent killing by PD-L1 t-haNKs in vitro and in vivo.

Conclusions: These results describe the underlying mechanisms governing synergistic antitumor activity between T cell-based immunotherapy that results in IFN-γ production, upregulation of PD-L1 on T-cell escape cells, and the use of PD-L1 CAR-engineered NK cells to target and eliminate resistant tumor cell populations.

Keywords: adoptive; combined modality therapy; head and neck neoplasms; immunotherapy.

Publication types

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

MeSH terms

  • Animals
  • B7-H1 Antigen / genetics
  • B7-H1 Antigen / metabolism
  • CRISPR-Cas Systems
  • Cell Line, Tumor
  • Databases, Genetic
  • Gene Editing*
  • HLA Antigens / metabolism
  • Head and Neck Neoplasms / genetics
  • Head and Neck Neoplasms / immunology
  • Head and Neck Neoplasms / metabolism
  • Head and Neck Neoplasms / therapy*
  • Humans
  • Immunotherapy, Adoptive*
  • Interferon-gamma / metabolism
  • Killer Cells, Natural / immunology
  • Killer Cells, Natural / metabolism
  • Killer Cells, Natural / transplantation*
  • Lymphocyte Activation
  • Lymphocytes, Tumor-Infiltrating / immunology*
  • Lymphocytes, Tumor-Infiltrating / metabolism
  • Mice
  • Mice, Inbred NOD
  • Mice, SCID
  • Receptors, Chimeric Antigen / genetics*
  • Receptors, Chimeric Antigen / immunology
  • Squamous Cell Carcinoma of Head and Neck / genetics
  • Squamous Cell Carcinoma of Head and Neck / immunology
  • Squamous Cell Carcinoma of Head and Neck / metabolism
  • Squamous Cell Carcinoma of Head and Neck / therapy*
  • T-Lymphocytes / immunology
  • T-Lymphocytes / metabolism
  • T-Lymphocytes / transplantation*
  • Tumor Burden
  • Tumor Escape*
  • Tumor Microenvironment
  • Xenograft Model Antitumor Assays


  • B7-H1 Antigen
  • CD274 protein, human
  • HLA Antigens
  • IFNG protein, human
  • Receptors, Chimeric Antigen
  • Interferon-gamma