Review
Copyright ©The Author(s) 2024. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Oct 15, 2024; 16(10): 4064-4079
Published online Oct 15, 2024. doi: 10.4251/wjgo.v16.i10.4064
Research progress of tumor-associated macrophages in immune checkpoint inhibitor tolerance in colorectal cancer
Qi Fan, Zheng-Wei Fu, Ming Xu, Feng Lv, Jia-Song Shi, Qi-Qi Zeng, De-Hai Xiong
Qi Fan, Zheng-Wei Fu, Ming Xu, Feng Lv, Jia-Song Shi, De-Hai Xiong, Intestinal Center, Chongqing University Three Gorges Hospital, Chongqing 404000, China
Qi-Qi Zeng, Department of Gastroenterology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, Jiangsu Province, China
Author contributions: Fan Q wrote the manuscript; Fu ZW, Xu M, Lv F, Shi JS, and Zeng QQ collected the data; Xiong DH guided the study. All authors reviewed, edited, and approved the final manuscript and revised it critically for important intellectual content, gave final approval of the version to be published, and agreed to be accountable for all aspects of the work.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
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: De-Hai Xiong, Doctor, Intestinal Center, Chongqing University Three Gorges Hospital, No. 165 Xincheng Road, Wanzhou District, Chongqing 404000, China. 1208505185@qq.com
Received: June 5, 2024
Revised: August 3, 2024
Accepted: August 16, 2024
Published online: October 15, 2024
Processing time: 113 Days and 1.1 Hours
Abstract

The relevant mechanism of tumor-associated macrophages (TAMs) in the treatment of colorectal cancer patients with immune checkpoint inhibitors (ICIs) is discussed, and the application prospects of TAMs in reversing the treatment tolerance of ICIs are discussed to provide a reference for related studies. As a class of drugs widely used in clinical tumor immunotherapy, ICIs can act on regulatory molecules on cells that play an inhibitory role-immune checkpoints-and kill tumors in the form of an immune response by activating a variety of immune cells in the immune system. The sensitivity of patients with different types of colorectal cancer to ICI treatment varies greatly. The phenotype and function of TAMs in the colorectal cancer microenvironment are closely related to the efficacy of ICIs. ICIs can regulate the phenotypic function of TAMs, and TAMs can also affect the tolerance of colorectal cancer to ICI therapy. TAMs play an important role in ICI resistance, and making full use of this target as a therapeutic strategy is expected to improve the immunotherapy efficacy and prognosis of patients with colorectal cancer.

Keywords: Colorectal cancer; Immune checkpoint inhibitor resistance; Tumor microenvironment; Tumor-associated macrophages; Review

Core Tip: This study reviews the role of tumor-associated macrophages (TAMs) in the treatment tolerance of immune checkpoint inhibitors in colorectal cancer. The effects of TAMs on immunotherapy through promoting immune escape, inhibiting T cell function, secreting pro-inflammatory factors and remodeling tumor microenvironment were discussed. In addition, the current therapeutic strategies against TAMs and their potential in improving the efficacy of immune checkpoint inhibitors are also introduced in this paper, aiming to provide new research directions and clinical application references for future colorectal cancer immunotherapy.