Anti-PD-1 antibody increases NK cell cytotoxicity towards nasopharyngeal carcinoma cells in the context of chemotherapy-induced upregulation of PD-1 and PD-L1

Anna Makowska,Pierre Busson,Selina Meier,Valentin Baloche,Udo Kontny,Lian Shen

doi:10.1007/s00262-020-02681-x

Abstract

BackgroundNasopharyngeal carcinoma (NPC) is a highly malignant epithelial cancer linked to Epstein–Barr virus (EBV) infection. Tumors are characterized by a lymphomononuclear infiltrate and the number of natural killer (NK) cells in tumors appears to be of prognostic significance. Standard treatment for NPC in adolescents and young adults consists of induction chemotherapy followed by radiochemotherapy. Though survival rates are above 80%, the majority of patients suffer from long-term side-effects, mainly related to radiotherapy. The addition of immunotherapy to induction chemotherapy could improve tumor response.MethodsWe have investigated the killing of NPC cells by NK cells in the context of chemotherapy, using a panel of three nasopharyngeal carcinoma cell lines and a patient-derived xenograft. Cytotoxicity was measured using the calcein-release assay, while the contribution of different checkpoints and signaling pathways to killing was studied by siRNA-mediated gene silencing and chemical inhibitors.ResultsChemotherapeutics cisplatin, 5-fluorouracil and gemcitabine sensitized NPC cells to killing by NK cells. Chemotherapeutics led to upregulation of PD-1 in NK cells and PD-L1 in NPC cells via NF-κB. Inhibition of the PD-L1/PD-1 checkpoint by an anti-PD-1 antibody or siRNA increased NK-cell cytotoxicity towards NPC cells.ConclusionThe addition of an anti-PD-1 antibody to chemotherapy in patients with NPC could increase the efficacy of induction chemotherapy. If confirmed in a clinical trial, more efficient induction therapy could allow the dose of radiotherapy to be reduced and thereby diminish severe late effects of such therapy.

Highlights

natural killer (NK) cells on Nasopharyngeal carcinoma (NPC) cells [16]
We demonstrate that (1) chemotherapeutics cisplatin, 5-fluorouracil and gemcitabine sensitize NPC cells to NK-cell killing, that (2) chemotherapeutics upregulate expression of PD-L1 in NPC cells and PD-1 in NK cells via the NF-κB-pathway, and that (3) blocking of the PD-L1/ PD-1 checkpoint further increases the killing of NPC cells by NK cells in the context of anticancer agents
We show that IFNβ increases the cytotoxic activity of NK cells against NPC cells treated with chemotherapeutics and that this effect can be augmented by disrupting the PD-L1/PD-1 interaction

Summary

Introduction

Chemotherapeutics are known to upregulate PD-L1 in cancer cells, and the addition of an anti-PD1 antibody to platin-containing induction chemotherapy has proved to significantly increase the response rate in patients with non-small cell lung cancer [17,18]. As neoadjuvant chemotherapy is nowadays increasingly used in adult patients with NPC [19], we decided to investigate the effect of chemotherapeutics on the killing of NPC cells by NK cells. Methods We have investigated the killing of NPC cells by NK cells in the context of chemotherapy, using a panel of three nasopharyngeal carcinoma cell lines and a patient-derived xenograft. Conclusion The addition of an anti-PD-1 antibody to chemotherapy in patients with NPC could increase the efficacy of induction chemotherapy. If confirmed in a clinical trial, more efficient induction therapy could allow the dose of radiotherapy to be reduced and thereby diminish severe late effects of such therapy

Methods

Results

Conclusion