Antitumor Effects of CAR T Cells Redirected to the EDB Splice Variant of Fibronectin

Cancer Immunol Res. 2021 Mar;9(3):279-290. doi: 10.1158/2326-6066.CIR-20-0280. Epub 2020 Dec 22.


Chimeric antigen receptor (CAR) T-cell therapy has had limited success in early-phase clinical studies for solid tumors. Lack of efficacy is most likely multifactorial, including a limited array of targetable antigens. We reasoned that targeting the cancer-specific extra domain B (EDB) splice variant of fibronectin might overcome this limitation because it is abundantly secreted by cancer cells and adheres to their cell surface. In vitro, EDB-CAR T cells recognized and killed EDB-positive tumor cells. In vivo, 1 × 106 EDB-CAR T cells had potent antitumor activity in both subcutaneous and systemic tumor xenograft models, resulting in a significant survival advantage in comparison with control mice. EDB-CAR T cells also targeted the tumor vasculature, as judged by IHC and imaging, and their antivascular activity was dependent on the secretion of EDB by tumor cells. Thus, targeting tumor-specific splice variants such as EDB with CAR T cells is feasible and has the potential to improve the efficacy of CAR T-cell therapy.

Publication types

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

MeSH terms

  • Animals
  • Antigens, Neoplasm
  • Cell Line, Tumor
  • Coculture Techniques
  • Feasibility Studies
  • Fibronectins / antagonists & inhibitors*
  • Fibronectins / genetics
  • Fibronectins / immunology
  • Fibronectins / metabolism
  • Healthy Volunteers
  • Human Umbilical Vein Endothelial Cells
  • Humans
  • Immunotherapy, Adoptive / methods*
  • Mice
  • Neoplasm Proteins / antagonists & inhibitors*
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / immunology
  • Neoplasm Proteins / metabolism
  • Neoplasms / immunology
  • Neoplasms / pathology
  • Neoplasms / therapy*
  • Primary Cell Culture
  • Protein Isoforms / antagonists & inhibitors
  • Protein Isoforms / genetics
  • Protein Isoforms / immunology
  • Protein Isoforms / metabolism
  • RNA Splicing
  • Receptors, Chimeric Antigen / immunology
  • T-Lymphocytes / immunology
  • T-Lymphocytes / transplantation*
  • Xenograft Model Antitumor Assays


  • Antigens, Neoplasm
  • FN1 protein, human
  • Fibronectins
  • Neoplasm Proteins
  • Protein Isoforms
  • Receptors, Chimeric Antigen