MicroRNAs in tumor immunity: functional regulation in tumor-associated macrophages.

Chong Chen; Jia-ming Liu; Yun-ping Luo

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MicroRNAs in tumor immunity: functional regulation in tumor-associated macrophages.

Author: Chong CHEN ^{1
,

2} ; Jia-Ming LIU ^{1
,

2} ; Yun-Ping LUO ^{1
,

2}
Author Information

1. Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences
2. School of Basic Medicine, Peking Union Medical College, Beijing 100005, China.
Publication Type:Review
Keywords: MicroRNA; Tumor microenvironment; Tumor-associated macrophage; Functional polarization
MeSH: Cell Communication; Cell Differentiation; Cell Polarity; Humans; Macrophages/physiology*; MicroRNAs/physiology*; Myeloid Cells/cytology*; Neoplasms/therapy*; Tumor Microenvironment
From: Journal of Zhejiang University. Science. B 2020;21(1):12-28
CountryChina
Language:English
Abstract: Tumor-associated macrophages (TAMs) are the most abundant immune cells in the tumor microenvironment (TME) and are critical for cancer initiation and progression. MicroRNAs (miRNAs) could notably influence the phenotype of TAMs through various targets and signal pathways during cancer progression due to their post-transcriptional regulation. In this review, we discuss mainly the regulatory function of miRNAs on macrophage differentiation, functional polarization, and cellular crosstalk. Firstly, during the generation process, miRNAs take part in the differentiation from myeloid cells to mature macrophages, and this maturation process directly influences their recruitment into the TME, attracted by tumor cells. Secondly, macrophages in the TME can be either tumor-promoting or tumor-suppressing, depending on their functional polarization. Large numbers of miRNAs can influence the polarization of macrophages, which is crucial for tumor progression, including tumor cell invasion, intravasation, extravasation, and premetastatic site formation. Thirdly, crosstalk between tumor cells and macrophages is essential for TME formation and tumor progression, and miRNAs can be the mediator of communication in different forms, especially when encapsulated in microvesicles or exosomes. We also assess the potential value of certain macrophage-related miRNAs (MRMs) as diagnostic and prognostic markers, and discuss the possible development of MRM-based therapies.