Interaction Between microRNAs and Myeloid-Derived Suppressor Cells in Tumor Microenvironment

Abstract

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of cells generated during a series of pathologic conditions including cancer. MicroRNA (miRNA) has been considered as a regulator in different tumor microenvironments. Recent studies have begun to unravel the crosstalk between miRNAs and MDSCs. The knowledge of the effect of both miRNAs and MDSCs in tumor may improve our understanding of the tumor immune escape and metastasis. The miRNAs target cellular signal pathways to promote or inhibit the function of MDSCs. On the other hand, MDSCs transfer bioinformation through exosomes containing miRNAs. In this review, we summarized and discussed the bidirectional regulation between miRNAs and MDSCs in the tumor microenvironment.

Exosomes‐mediated crosstalk between glioma and immune cells in the tumor microenvironment

“…Tumor cells typically invade normal tissues and establish a tumor microenvironment (TME) consisting of immune cells, stromal cells, vascular endothelial cells, and extracellular matrix (ECM) 76–79 . Tumor cells can recruit and activate these components to form a tumor‐inhibiting inflammatory microenvironment, which can prevent tumor progression during the early stages of colonization or proliferation 80,81 (Figure 1).…”

“…Tumor cells typically invade normal tissues and establish a tumor microenvironment (TME) consisting of immune cells, stromal cells, vascular endothelial cells, and extracellular matrix (ECM). [76][77][78][79] Tumor cells can recruit and activate these components to form a tumorinhibiting inflammatory microenvironment, which can prevent tumor progression during the early stages of colonization or proliferation 80,81 (Figure 1). However, persistent tumor antigen stimulation and immune activation can lead to a depleted or remodeled state of the effector cells in the microenvironment, resulting in an immunosuppressive microenvironment that promotes malignant tumor phenotypes [82][83][84] (Figure 1).…”

Role of Exosomes in Immunotherapy of Hepatocellular Carcinoma

“…Recent study has revealed that HCC-derived exosomal HGMB1 can foster HCC immune evasion by promoting TIM-1+ regulatory B cell expansion [ 58 ]. Exosomes derived from myeloid-derived suppressor cells, a type of special cell in tumor immunity, play important immunoregulatory roles in cancers, and tumor-derived exosomes also regulate the function of myeloid-derived suppressor cells [ 59 , 60 , 61 ]. Unfortunately, no relevant studies have been undertaken in HCC.…”

MSC microvesicles loaded G-quadruplex-enhanced circular single-stranded DNA-9 inhibits tumor growth by targeting MDSCs

“…miRNAs play crucial roles in the regulation of diverse biological processes, including tumorigenesis and inflammation [ 8 , 9 ]. Many studies have been shown that miRNAs regulate MDSCs maturation, differentiation and function [ 10 ]. Therefore, regulating the levels of miRNAs in MDSCs may modulate the immunosuppressive microenvironment of tumors and inhibit their malignant evolution.…”