Cancer-derived exosomic microRNAs shape the immune system within the tumor microenvironment: State of the art

Abstract

In recent years there has been an increasing interest of the scientific community on exosome research, with particular emphasis on the mechanisms by which tumor-derived exosomes can promote tumor growth. Particularly, exosome-mediated immune-escape is under deep investigation and still represents a quite controversial issue. Tumor-derived exosomes are carriers of information able to reprogram functions of immune target cells, influencing their development, maturation, and antitumor activities. They deliver proteins similar to those of the parent cancer cells, but also genetic messages like genomic DNA, mRNA, and microRNAs (miRNAs) that ultimately share the so called “tumor microenvironment” in a pro-tumoral fashion. The content of tumor-derived exosomes could be implicated in several signaling pathways operating in the tumor microenvironment, providing a further modality of dys-regulation of antitumor immunity. The aim of this review is to provide a state-of-the-art highlight of to the most recent discoveries in the field of interaction between tumor-derived exosomic miRNAs and the cells of immune system.

The role of cancer-derived microRNAs in cancer immune escape

“…Cancer-derived miRNAs could be packed into exosomes or microvesicles, which are transferred to numerous TILs and shape an immunosuppressive microenvironment (Fig. 3) [141]. [125].…”

Identification and validation of circulating exosomes‐based liquid biopsy for esophageal cancer

“…The short noncoding RNAs carried by exosomes have attracted increasing interests in the intercellular communication field based on the premise that exosome may act as the effector of tumorigenesis and also increase the complexity of tumor processes . Several studies have been demonstrated that exosomes secreted by tumor could shuttle short RNA to cells in the tumor microenvironment to promote tumor metastasis and inhibit the immune response . The identification of the functional RNA, noncoding RNA or other nucleic acid within CEs by high throughput sequencing technologies needs to be carried out in the future.…”

“…19,20 Several studies have been demonstrated that exosomes secreted by tumor could shuttle short RNA to cells in the tumor microenvironment to promote tumor metastasis and inhibit the immune response. 21,22 The identification of the functional RNA, noncoding RNA or other nucleic acid within CEs by high throughput sequencing technologies needs to be carried out in the future.…”

Exosomal FMR1-AS1 facilitates maintaining cancer stem-like cell dynamic equilibrium via TLR7/NFκB/c-Myc signaling in female esophageal carcinoma

“…Exosomes secreted by tumor cells provide a physical means to transfer a variety of intracellular molecules into the surrounding cells, where these molecules exert regulatory effects, and may serve as important molecular information carriers to communicate with CSCs, non-CSCs and other cells in tumor microenvironment [15,16]. Tumorcell-derived exosomes are found in all body fluids, upon contact with target cells, they can alter phenotypic and functional attributes of recipients, reprogramming them into active contributors to tumor growth, metastasis and immunosuppression [17][18][19]. However, the role of exosomes, specifically exosomal lncRNAs, in the reciprocal conversion between non-CSCs and CSCs was rarely investigated.…”