Basic Study
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Jun 15, 2022; 14(6): 1124-1140
Published online Jun 15, 2022. doi: 10.4251/wjgo.v14.i6.1124
Glutamine deprivation impairs function of infiltrating CD8+ T cells in hepatocellular carcinoma by inducing mitochondrial damage and apoptosis
Wei Wang, Meng-Nan Guo, Ning Li, De-Quan Pang, Jing-Hua Wu
Wei Wang, Meng-Nan Guo, Jing-Hua Wu, Department of Laboratory Medicine, Tangshan Maternal and Child Health Care Hospital, North China University of Science and Technology, Tangshan 063000, Hebei Province, China
Ning Li, Department of Laboratory Medicine, North China University of Science and Technology Affiliated Hospital, Tangshan 063000, Hebei Province, China
De-Quan Pang, Department of Oncology, North China University of Science and Technology Affiliated Hospital, Tangshan 063000, Hebei Province, China
Author contributions: Wang W participated in the writing and editing of the manuscript; Guo MN and Li N participated in the data analysis; Pang DQ participated in the clinical specimen collection; Wu JH provided the experimental idea; all the authors approved for the final version of the manuscript.
Supported by High-End Talent Funding Project in Hebei Province, No. A202003005; Hebei Provincial Health Commission Office, No. G2019074; and Natural Science Foundation of Hebei Province, No. H2019209355.
Institutional review board statement: The study was approved by the Medical Ethics Committee of North China University of Science and Technology (No. 2018109).
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Jing-Hua Wu, MD, PhD, Chief Technician, Professor, Department of Laboratory Medicine, Tangshan Maternal and Child Health Care Hospital, North China University of Science and Technology, No. 1 Hetai Road, Lunan District, Tangshan 063000, Hebei Province, China. tswujinghua@163.com
Received: December 18, 2021
Peer-review started: December 18, 2021
First decision: April 17, 2022
Revised: April 22, 2022
Accepted: May 21, 2022
Article in press: May 21, 2022
Published online: June 15, 2022
Processing time: 173 Days and 19.7 Hours
Abstract
BACKGROUND

The functions of infiltrating CD8+ T cells are often impaired due to tumor cells causing nutrient deprivation in the tumor microenvironment. Thus, the mechanisms of CD8+ T cell dysfunction have become a hot research topic, and there is increased interest on how changes in metabolomics correlate with CD8+ T cell dysfunction.

AIM

To investigate whether and how glutamine metabolism affects the function of infiltrating CD8+ T cells in hepatocellular carcinoma.

METHODS

Immunohistochemical staining and immunofluorescence were performed on surgically resected liver tissues from patients. Differentially expressed genes in infiltrating CD8+ T cells in hepatocellular carcinoma were detected using RNA sequencing. Activated CD8+ T cells were co-cultured with Huh-7 cells for 3 d. The function and mitochondrial status of CD8+ T cells were analyzed by flow cytometry, quantitative real-time polymerase chain reaction, and transmission electron microscopy. Next, CD8+ T cells were treated with the mitochondrial protective and damaging agents. Functional alterations in CD8+ T cells were detected by flow cytometry. Then, complete medium without glutamine was used to culture cells and their functional changes and mitochondrial status were detected.

RESULTS

There were a large number of infiltrating PD-1+CD8+ T cells in liver cancer tissues. Next, we co-cultured CD8+ T cells and Huh-7 cells to explore the regulatory effect of hepatoma cells on CD8+ T cells. Flow cytometry results revealed increased PD-1 expression and decreased secretion of perforin (PRF1) and granzyme B (GZMB) by CD8+ T cells in the co-culture group. Meanwhile, JC-1 staining was decreased and the levels of reactive oxygen species and apoptosis were increased in CD8+ T cells of the co-culture group; additionally, the mitochondria of these cells were swollen. When CD8+ T cells were treated with the mitochondrial protective and damaging agents, their function was restored and inhibited, respectively, through the mitochondrial damage and apoptotic pathways. Subsequently, complete medium without glutamine was used to culture cells. As expected, CD8+ T cells showed functional downregulation, mitochondrial damage, and apoptosis.

CONCLUSION

Glutamine deprivation impairs the function of infiltrating CD8+ T cells in hepatocellular carcinoma through the mitochondrial damage and apoptotic pathways.

Keywords: Glutamine; Mitochondrial damage; CD8+ T cells; T cell function; Hepatocellular carcinoma

Core Tip: This study aimed to investigate whether and how glutamine metabolism affects the function of infiltrating CD8+ T cells in hepatocellular carcinoma. Experimental validation was performed by using liver cancer tissues and cell lines. We discovered that glutamine deprivation impaired the function of infiltrating CD8+ T cells in hepatocellular carcinoma through the mitochondrial damage and apoptotic pathways.