Phenotypic Characterization by Single-Cell Mass Cytometry of Human Intrahepatic and Peripheral NK Cells in Patients with Hepatocellular Carcinoma.

Yuichi Yoshida,Toru Okamoto,Yu Takahashi,Sachiyo Yoshio,Ryuki Hashida,Taiji Yamazoe,Hironari Kawai,Taizo Mori,Takumi Kawaguchi,Akinobu Taketomi,Yoshihiro Ono,Tatsuya Kanto,Shiori Yoshikawa,Yuriko Tsustui,Takasuke Fukuhara

doi:10.3390/cells10061495

Abstract

Overall response rates of systemic therapies against advanced hepatocellular carcinoma (HCC) remain unsatisfactory. Thus, searching for new immunotherapy targets is indispensable. NK cells are crucial effectors and regulators in the tumor microenvironment and a determinant of responsiveness to checkpoint inhibitors. We revealed the landscape of NK cell phenotypes in HCC patients to find potential immunotherapy targets. Using single cell mass cytometry, we analyzed 32 surface markers on CD56dim and CD56bright NK cells, which included Sialic acid-binding immunoglobulin-type lectins (Siglecs). We compared peripheral NK cells between HCC patients and healthy volunteers. We also compared NK cells, in terms of their localizations, on an individual patient bases between peripheral and intrahepatic NK cells from cancerous and noncancerous liver tissues. In the HCC patient periphery, CD160+CD56dim NK cells that expressed Siglec-7, NKp46, and NKp30 were reduced, while CD49a+CD56dim NK cells that expressed Siglec-10 were increased. CD160 and CD49a on CD56dim NK cells were significantly correlated to other NK-related markers in HCC patients, which suggested that CD160 and CD49a were signature molecules. CD49a+ CX3CR1+ Siglec-10+ NK cells had accumulated in HCC tissues. Considering further functional analyses, CD160, CD49a, CX3CR1, and Siglec-10 on CD56dim NK cells may be targets for immunotherapies of HCC patients.

Highlights

Hepatocellular carcinoma (HCC) accounts for approximately 90% of primary liver cancers is the third leading cause of cancer deaths and is the fourth most common cancer worldwide [1,2]
We successfully identified a novel subpopulation of NK cells among Peripheral blood mononuclear cells (PBMCs) and in HCC tissues of patients, which consist of CD49a+CD56dim NK cells with enhanced expression of CX3CR1, Sialic acid-binding immunoglobulin-type lectins (Siglecs)-10, ILT2, and PD-1
In addition to CD49a, we found that the expression levels and frequencies of Siglec-10, ILT2, PD-1, and CX3CR1 were significantly increased in Ca-CD56dim NK cells (3B-3E)

Summary

Introduction

Hepatocellular carcinoma (HCC) accounts for approximately 90% of primary liver cancers is the third leading cause of cancer deaths and is the fourth most common cancer worldwide [1,2]. For early-stage HCC patients with no history of cirrhosis or portal hypertension, resection is recommended, but it is associated with recurrence rates of 60–70% at 5 years [3], which requires repeated resection and further treatment. Sorafenib (multikinase inhibitor) was the only first-line systemic targeted drug available for advanced HCC patients with a survival benefit of only 3 months. Treatments for advanced HCC patients have considerably improved over the last few years, which include immune checkpoint inhibitors (anti-PD-1 and anti-PD-L1) [4]. Searching for new therapeutic targets of immunological therapies is still required to improve the prognosis of patients with advanced HCC. NK cells play a critical role in regulating immune responses against tumors [5,6] and define responsiveness to checkpoint therapies in various tumor microenvironments [7]. Exploring the landscape of NK cells in HCC patients may provide a novel framework for possible immunomodulatory strategies

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Conclusion