Chemical inhibition of DNA-PKcs impairs the activation and cytotoxicity of CD4+ helper and CD8+ effector T cells

Immunol Cell Biol. 2023 Aug;101(7):663-671. doi: 10.1111/imcb.12651. Epub 2023 May 6.


Modulation of T cell activity is an effective strategy for the treatment of autoimmune diseases, immune-related disorders and cancer. This highlights a critical need for the identification of proteins that regulate T cell function. The kinase DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is emerging as a potent regulator of the immune system, spurring interest in its use as a therapeutic target. In murine models of immune-related diseases including asthma and rheumatoid arthritis, treatment with small-molecule DNA-PKcs inhibitors decreased the disease severity. Additionally, DNA-PKcs inhibitors reduced T cell-mediated graft rejection in a murine allogenic skin graft model. These in vivo studies suggest the use of DNA-PKcs inhibitors as immunotherapy for autoimmune and T cell-mediated disorders. In this study, we sought to characterize further the effects of DNA-PKcs inhibitors on T cells to better understand their clinical potential. We determined that inhibition of DNA-PKcs using inhibitor NU7441 and the inhibitors currently in clinical trials for cancer therapy, M3184 and AZD7648, abrogated the activation of murine and human CD4+ and CD8+ T cells as evidenced by the reduced expression of the activation markers CD69 and CD25. Furthermore, inhibition of DNA-PKcs impeded metabolic pathways and the proliferation of activated T cells. This reduced the ability of OTI-CD8+ T cells to kill cancer cells and the expression of IFNγ and cytotoxic genes. These results highlight a critical role for DNA-PKcs in T cells and validate future studies using DNA-PKcs inhibitors as immune modulation therapy for the treatment of immune-related diseases.

Keywords: CD4+ helper T cells; CD8+ effector T cells; DNA dependent protein kinase catalytic subunit; NU7441T cell activation; OTISIINFEKL-MC38; T cell metabolism; cytotoxicity.

Publication types

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

MeSH terms

  • Animals
  • Antineoplastic Agents*
  • CD4-Positive T-Lymphocytes / metabolism
  • CD8-Positive T-Lymphocytes / metabolism
  • DNA
  • DNA-Activated Protein Kinase* / genetics
  • DNA-Activated Protein Kinase* / metabolism
  • Humans
  • Mice


  • DNA-Activated Protein Kinase
  • Antineoplastic Agents
  • DNA