Targeting VEGFR2 with Ramucirumab strongly impacts effector/ activated regulatory T cells and CD8+ T cells in the tumor microenvironment

Yasuko Tada, Yosuke Togashi, Daisuke Kotani, Takeshi Kuwata, Eichi Sato, Akihito Kawazoe, Toshihiko Doi, Hisashi Wada, Hiroyoshi Nishikawa, Kohei Shitara

Research output: Contribution to journalArticlepeer-review

71 Citations (Scopus)

Abstract

Background: Several studies have established a correlation between the VEGF-VEGFR2 axis and an immunosuppressive microenvironment; this immunosuppression can be overcome by anti-angiogenic reagents, such as ramucirumab (RAM). However, little is known about the immunological impact of anti-angiogenic reagents within the tumor microenvironment in human clinical samples. This study aimed at investigating the effects of RAM on the tumor microenvironmental immune status in human cancers. Methods: We prospectively enrolled 20 patients with advanced gastric cancer (GC) who received RAM-containing chemotherapy. We obtained paired samples from peripheral blood mononuclear cells (PBMCs) and tumor-infiltrating lymphocytes (TILs) in primary tumors both pre- and post-RAM therapy to assess immune profiles by immunohistochemistry and flow cytometry. Results: Within the tumor microenvironment, both PD-L1 expression and CD8+ T-cell infiltration increased after RAM-containing therapies. In addition, CD45RA-FOXP3highCD4+ cells (effector regulatory T cells [eTreg cells]) and PD-1 expression by CD8+ T cells were significantly reduced in TILs compared with PBMCs after RAM-containing therapies. Patients with partial response and longer progression-free survival had significantly higher pre-treatment eTreg frequencies in TILs than those with progressive disease. In in vitro analysis, VEGFR2 was highly expressed by eTreg cells. Further, VEGFA promoted VEGFR2+ eTreg cell proliferation, and this effect could be inhibited by RAM. Conclusions: This study suggests that the frequency of eTreg cells in TILs could be a biomarker for stratifying clinical responses to RAM-containing therapies. Further, we propose that RAM may be employed as an immuno-modulator in combination with immune checkpoint blockade.

Original languageEnglish
Article number106
JournalJournal for immunotherapy of cancer
Volume6
Issue number1
DOIs
Publication statusPublished - Oct 11 2018
Externally publishedYes

Keywords

  • Gastric cancer
  • PD-1
  • Ramucirumab
  • Regulatory T cells
  • VEGFR2

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Molecular Medicine
  • Oncology
  • Pharmacology
  • Cancer Research

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