Cytotoxicity of Human Hepatic Intrasinusoidal CD56bright Natural Killer Cells against Hepatocellular Carcinoma Cells

Abstract

Hepatic intrasinusoidal (HI) natural killer (NK) cells from liver perfusate have unique features that are similar to those of liver-resident NK cells. Previously, we have reported that HI CD56bright NK cells effectively degranulate against SNU398 hepatocellular carcinoma (HCC) cells. Thus, the aim of this study was to further investigate the phenotype and function of HI NK cells. We found that HI CD56bright NK cells degranulated much less to Huh7 cells. HI CD56bright NK cells expressed NKG2D, NKp46, TNF-related apoptosis-inducing ligand (TRAIL), and FAS ligand (FASL) at higher levels than CD56dim cells. SNU398 cells expressed more NKG2D ligands and FAS and less PD-L1 than Huh7 cells. Blockade of NKG2D, TRAIL, and FASL significantly reduced the cytotoxicity of HI NK cells against SNU398 cells, but blockade of PD-L1 did not lead to any significant change. However, HI NK cells produced IFN-γ well in response to Huh7 cells. In conclusion, the cytotoxicity of HI CD56bright NK cells was attributed to the expression of NKG2D, TRAIL, and FASL. The results suggest the possible use of HI NK cells for cancer immunotherapy and prescreening of HCC cells to help identify the most effective NK cell therapy recipients.

The Role of TRAIL/DRs in the Modulation of Immune Cells and Responses

“…Many immune cells express TRAIL constitutively or following activation and thereby can be cytotoxic to TRAIL-sensitive tumor cells in vitro and in vivo. This has been reported for neutrophils [13,14,17,42,43], monocytes/macrophages [17,47,52,73], DCs [46,49,77,78,79,81,82,83,86,87,91,98,102,103,104], pDCs [84,85,88,91,93,95,96,105], cNK/ILC1s [134,136,137,163,228,282], i NKT cells [218,219,225,227,229], γδ T cells [231,235], and conventional T cells [186,194,283,284,285,286].…”

“…In those reports were a subset of blood-derived NK cells stained for surface TRAIL, it was found exclusively on the CD56 bright population [128,132] and large inter-individual variability was noted [132]. In contrast to the blood, most [128,133,134] but not all [135] studies demonstrated surface TRAIL expression on human liver CD56 bright NK cells. A similar expression profile was seen in mice, where only a subset of NK cells in the liver, but not in blood, spleen, or lung, constitutively expressed TRAIL [136,137,138].…”

Recent Advances in Molecular Mechanisms of the NKG2D Pathway in Hepatocellular Carcinoma

“…The activation of NKG2D receptors can promote the release of multiple active proteins from NK cells, such as perforin and granzymes, and can also induce the expression of tumor necrosis factor (TNF) ligand interferon-gamma (IFN-γ) to induce apoptosis of hepatocarcinoma and is beneficial to clean up the tumor ( Figure 6). An exciting novel research results also had been shown that the NK cells with positive CD56 bright located in human hepatic sinuses had effective cytotoxicity against SNU398 hepatoma cells through multiple signaling pathways (such as high expression in NKG2D, NKp46, TRAIL, FasL, and others), which were very helpful for the immunotherapy of hepatocellular carcinoma [66].…”

“…When the neutralizing antibodies were injected intraperitoneally to deplete CD8 + T cells or NK cells, the cytotoxicity to hepatocellular carcinoma was significantly weakened. On this basis, Hwang et al [66] further explored the phenotype and function of NK cells in human hepatic sinusoids and their cytotoxicity to hepatocellular carcinoma cells. It was found that NKG2D, NKP46, TNF-related apoptosis-inducing ligand (TRAIL), and Fas ligand (FASL) were highly expressed in hepatic intrasinusoidal (HI) CD56 bright NK cells, which had little degranulation effect on Huh7 cells, but could secrete more IFN-γ to produce strong cytotoxicity on Huh7 cells.…”

Cytotoxic immune cell-based immunotherapy for hepatocellular carcinoma

“…These findings suggest that liver-resident NK cells play versatile roles in liver diseases. Human liver-resident NK cells are CD56 bright Eomes hi Tbet lo Hobit + TIGIT + CD69 + CXCR6 + CD49e -; express higher levels of NKG2D, NKp46, TRAIL, and FasL; and possess cytotoxicity against HCC cells [36] . However, liver-resident NK cells within the HCC tissue down-regulate NKG2D [37] .…”