Targeting CD47 Enhances the Efficacy of Anti-PD-1 and CTLA-4 in an Esophageal Squamous Cell Cancer Preclinical Model

Oncol Res. 2017 Nov 2;25(9):1579-1587. doi: 10.3727/096504017X14900505020895. Epub 2017 Mar 23.

Abstract

Esophageal squamous cell cancer is a highly aggressive cancer with a dismal 5-year survival rate. CD47 is a cell transmembrane protein that is involved in cell apoptosis, proliferation, adhesion, migration, and antigen presentation in the immune system. By interacting with signal regulatory protein-α expressed in antigen-presenting cells (APCs), CD47 acts as an antiphagocytic mechanism to inhibit APC-dependent antigen presentation. Overexpression of CD47 was found in various types of cancer. However, its role in esophageal squamous cell cancer is not yet clear. Anti-CD47 is an antagonist of CD47 signaling pathways by competing with its ligand. In the current study, we investigated the effects of anti-CD47 treatment on the antitumor immune response in an esophageal squamous cell cancer preclinical model. We found that anti-CD47 treatment enhanced proinflammatory responses and increased CD8+ T-cell infiltration in tumor tissue in the animal model. T cells in anti-CD47-treated tumors showed higher PD-1 and CTLA-4 expression, indicating T-cell activation and the rationale of combining anti-CD47 with anti-PD-1 and CLTA-4. The combinatory treatment showed the best antitumor response, implying a novel treatment strategy. The effects of anti-CD47 depended on dendritic cell function. In patient samples, expression of CD47 was negatively correlated with CD8+ T-cell infiltration in esophageal squamous cell cancer patients. Taken together, CD47 might be a novel target to enhance anti-PD-1 and CLTA-4 efficacy in esophageal squamous cell cancer.

MeSH terms

  • Animals
  • Antibodies / immunology
  • Antibodies / pharmacology
  • CD47 Antigen / antagonists & inhibitors*
  • CD47 Antigen / immunology
  • CTLA-4 Antigen / antagonists & inhibitors*
  • CTLA-4 Antigen / immunology
  • Carcinoma, Squamous Cell / immunology
  • Carcinoma, Squamous Cell / pathology
  • Carcinoma, Squamous Cell / therapy*
  • Cell Line, Tumor
  • Dendritic Cells / metabolism*
  • Disease Models, Animal
  • Esophageal Neoplasms / immunology
  • Esophageal Neoplasms / pathology
  • Esophageal Neoplasms / therapy*
  • Esophageal Squamous Cell Carcinoma
  • Female
  • Humans
  • Lymphocytes, Tumor-Infiltrating / immunology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Programmed Cell Death 1 Receptor / antagonists & inhibitors*
  • Programmed Cell Death 1 Receptor / immunology
  • Signal Transduction
  • Transfection

Substances

  • Antibodies
  • CD47 Antigen
  • CTLA-4 Antigen
  • Programmed Cell Death 1 Receptor