Decitabine Enhances Lymphocyte Migration and Function and Synergizes with CTLA-4 Blockade in a Murine Ovarian Cancer Model

Cancer Immunol Res. 2015 Sep;3(9):1030-41. doi: 10.1158/2326-6066.CIR-15-0073. Epub 2015 Jun 8.

Abstract

The lack of second-line treatment for relapsed ovarian cancer necessitates the development of improved combination therapies. Targeted therapy and immunotherapy each confer clinical benefit, albeit limited as monotherapies. Ovarian cancer is not particularly responsive to immune checkpoint blockade, so combination with a complementary therapy may be beneficial. Recent studies have revealed that a DNA methyl transferase inhibitor, azacytidine, alters expression of immunoregulatory genes in ovarian cancer. In this study, the antitumor effects of a related DNA methyl transferase inhibitor, decitabine (DAC), were demonstrated in a syngeneic murine ovarian cancer model. Low-dose DAC treatment increases the expression of chemokines that recruit NK cells and CD8(+) T cells, promotes their production of IFNγ and TNFα, and extends the survival of mice bearing subcutaneous or orthotopic tumors. While neither DAC nor immune checkpoint blockade confers durable responses as a monotherapy in this model, the efficacy of anti-CTLA-4 was potentiated by combination with DAC. This combination promotes differentiation of naïve T cells into effector T cells and prolongs cytotoxic lymphocyte responses as well as mouse survival. These results suggest that this combination therapy may be worthy of further consideration for improved treatment of drug-resistant ovarian cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology
  • Antineoplastic Agents / therapeutic use*
  • Ascitic Fluid / immunology
  • Azacitidine / administration & dosage
  • Azacitidine / analogs & derivatives*
  • Azacitidine / pharmacology
  • Azacitidine / therapeutic use
  • CD8-Positive T-Lymphocytes / immunology
  • CTLA-4 Antigen / antagonists & inhibitors*
  • Cell Movement / drug effects
  • Cell Transformation, Neoplastic / drug effects
  • Cell Transformation, Neoplastic / immunology
  • Cytokines / biosynthesis
  • Decitabine
  • Female
  • Gene Expression Regulation, Neoplastic / drug effects
  • Gene Expression Regulation, Neoplastic / immunology
  • Humans
  • Immunotherapy / methods
  • Killer Cells, Natural / drug effects
  • Killer Cells, Natural / immunology
  • Lymph Nodes / immunology
  • Lymphocytes, Tumor-Infiltrating / drug effects*
  • Lymphocytes, Tumor-Infiltrating / immunology
  • Mice
  • Ovarian Neoplasms / drug therapy*
  • Ovarian Neoplasms / immunology
  • Tumor Cells, Cultured
  • Xenograft Model Antitumor Assays / methods

Substances

  • Antineoplastic Agents
  • CTLA-4 Antigen
  • Cytokines
  • Decitabine
  • Azacitidine