Epigenetic priming of both tumor and NK cells augments antibody-dependent cellular cytotoxicity elicited by the anti-PD-L1 antibody avelumab against multiple carcinoma cell types

Kristin C. Hicks, Massimo Fantini, Renee N. Donahue, Angie Schwab, Karin M. Knudson, Sarah R. Tritsch, Caroline Jochems, Paul E. Clavijo, Clint T. Allen, James W. Hodge, Kwong Y. Tsang, Jeffrey Schlom, Sofia R. Gameiro

Research output: Contribution to journalArticle

Abstract

Checkpoint inhibitors targeting the PD-1/PD-L1 axis are promising immunotherapies shown to elicit objective responses against multiple tumor types, yet these agents fail to benefit most patients with carcinomas. This highlights the need to develop effective therapeutic strategies to increase responses to PD-1/PD-L1 blockade. Histone deacetylase (HDAC) inhibitors in combination with immunotherapies have provided preliminary evidence of anti-tumor effects. We investigated here whether exposure of either natural killer (NK) cells and/or tumor cells to two different classes of HDAC inhibitors would augment (a) NK cell‒mediated direct tumor cell killing and/or (b) antibody-dependent cellular cytotoxicity (ADCC) using avelumab, a fully human IgG1 monoclonal antibody targeting PD-L1. Treatment of a diverse array of human carcinoma cells with a clinically relevant dose of either the pan-HDAC inhibitor vorinostat or the class I HDAC inhibitor entinostat significantly enhanced the expression of multiple NK ligands and death receptors resulting in enhanced NK cell‒mediated lysis. Moreover, HDAC inhibition enhanced tumor cell PD-L1 expression both in vitro and in carcinoma xenografts. These data demonstrate that treatment of a diverse array of carcinoma cells with two different classes of HDAC inhibitors results in enhanced NK cell tumor cell lysis and avelumab-mediated ADCC. Furthermore, entinostat treatment of NK cells from healthy donors and PBMCs from cancer patients induced an activated NK cell phenotype, and heightened direct and ADCC-mediated healthy donor NK lysis of multiple carcinoma types. This study thus extends the mechanism and provides a rationale for combining HDAC inhibitors with PD-1/PD-L1 checkpoint blockade to increase patient responses to anti-PD-1/PD-L1 therapies.

Original languageEnglish (US)
Article numbere1466018
JournalOncoImmunology
Volume7
Issue number11
DOIs
StatePublished - Nov 2 2018

Keywords

  • ADCC
  • HDAC
  • NK cell function
  • PD-L1
  • avelumab
  • checkpoint inhibitor
  • entinostat
  • histone deacetylase
  • solid carcinoma
  • vorinostat

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Oncology

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  • Cite this

    Hicks, K. C., Fantini, M., Donahue, R. N., Schwab, A., Knudson, K. M., Tritsch, S. R., Jochems, C., Clavijo, P. E., Allen, C. T., Hodge, J. W., Tsang, K. Y., Schlom, J., & Gameiro, S. R. (2018). Epigenetic priming of both tumor and NK cells augments antibody-dependent cellular cytotoxicity elicited by the anti-PD-L1 antibody avelumab against multiple carcinoma cell types. OncoImmunology, 7(11), [e1466018]. https://doi.org/10.1080/2162402X.2018.1466018