Ex vivo Hsp70-Activated NK Cells in Combination With PD-1 Inhibition Significantly Increase Overall Survival in Preclinical Models of Glioblastoma and Lung Cancer

Front Immunol. 2019 Mar 22:10:454. doi: 10.3389/fimmu.2019.00454. eCollection 2019.

Abstract

Heat shock protein 70 (Hsp70) which is expressed on the plasma membrane of highly aggressive tumors including non-small cell lung carcinoma and glioblastoma multiforme serves as a target for Hsp70-targeting NK cells. Herein, we aimed to investigate the antitumor effects of a combined therapy consisting of ex vivo Hsp70-peptide TKD/IL-2-activated NK cells in combination with mouse/human anti-PD-1 antibody in a syngeneic glioblastoma and a xenograft lung cancer mouse model. Mice with membrane Hsp70 positive syngeneic GL261 glioblastoma or human xenograft A549 lung tumors were sham-treated with PBS or injected with ex vivo TKD/IL-2-activated mouse/human NK cells and mouse/human PD-1 antibody either as a single regimen or in combination. Tumor volume was assessed by MR scanning and tumor-infiltrating CD8+ T, NK, and PD-1+ cells were quantified by immunohistochemistry (IHC). We could show that the adoptive transfer of ex vivo TKD/IL-2-activated mouse NK cells or the inhibition of PD-1 resulted in tumor growth delay and an improved overall survival (OS) in a syngeneic glioblastoma mouse model. A combination of both therapies was well-tolerated and significantly more effective with respect to both outcome parameters than either of the single regimens. A combined treatment in a xenograft lung cancer model showed identical effects in immunodeficient mice bearing human lung cancer after adoptive transfer of TKD/IL-2-activated human effector cells and a human PD-1 antibody. Tumor control was associated with a massive infiltration with CD8+ T and NK cells in both tumor models and a decreased in PD-1 expression on immune effector cells. In summary, a combined approach consisting of activated NK cells and anti-PD-1 therapy is safe and results in a long-term tumor control which is accompanied by a massive tumor immune cell infiltration in 2 preclinical tumor models.

Keywords: NK cell therapy; anti-PD-1 antibody; glioblastoma; immunophenotyping; lung carcinoma; membrane Hsp70.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • A549 Cells
  • Animals
  • Antibodies, Neoplasm / pharmacology*
  • Carcinoma, Non-Small-Cell Lung* / immunology
  • Carcinoma, Non-Small-Cell Lung* / pathology
  • Carcinoma, Non-Small-Cell Lung* / therapy
  • Glioblastoma* / immunology
  • Glioblastoma* / pathology
  • Glioblastoma* / therapy
  • HSP70 Heat-Shock Proteins / immunology*
  • Humans
  • Immunotherapy*
  • K562 Cells
  • Killer Cells, Natural* / immunology
  • Killer Cells, Natural* / pathology
  • Killer Cells, Natural* / transplantation
  • Lung Neoplasms* / immunology
  • Lung Neoplasms* / pathology
  • Lung Neoplasms* / therapy
  • Male
  • Mice
  • Mice, Nude
  • Neoplasm Proteins / antagonists & inhibitors*
  • Neoplasm Proteins / immunology
  • Neoplasms, Experimental* / immunology
  • Neoplasms, Experimental* / pathology
  • Neoplasms, Experimental* / therapy
  • Programmed Cell Death 1 Receptor / antagonists & inhibitors*
  • Programmed Cell Death 1 Receptor / immunology
  • Xenograft Model Antitumor Assays

Substances

  • Antibodies, Neoplasm
  • HSP70 Heat-Shock Proteins
  • Neoplasm Proteins
  • PDCD1 protein, human
  • Pdcd1 protein, mouse
  • Programmed Cell Death 1 Receptor