The Role of miR-155 in Antitumor Immunity

Abstract

MicroRNAs belong to a group of short non-coding RNA molecules that are involved in the regulation of gene expression at multiple levels. Their function was described two decades ago, and, since then, microRNAs have become a rapidly developing field of research. Their participation in the regulation of cellular processes, such as proliferation, apoptosis, cell growth, and migration, made microRNAs attractive for cancer research. Moreover, as a single microRNA can simultaneously target multiple molecules, microRNAs offer a unique advantage in regulating multiple cellular processes in different cell types. Many of these cell types are tumor cells and the cells of the immune system. One of the most studied microRNAs in the context of cancer and the immune system is miR-155. MiR-155 plays a role in modulating innate and adaptive immune mechanisms in distinct immune cell types. As such, miR-155 can be part of the communication between the tumor and immune cells and thus impact the process of tumor immunoediting. Several studies have already revealed its effect on antitumor immune responses, and the targeting of this molecule is increasingly implemented in cancer immunotherapy. In this review, we discuss the current knowledge of miR-155 in the regulation of antitumor immunity and the shaping of the tumor microenvironment, and the plausible implementation of miR-155 targeting in cancer therapy.

MicroRNA-155 and Disease-Related Immunohistochemical Parameters in Cutaneous Melanoma

“…MiR-155 is an essential regulator of cancer biology and has been linked to the development and progression of malignant melanoma [ 26 , 63 , 64 , 65 ]. Similar to our findings that revealed miR-155 downregulation in melanoma tissues compared to non-cancer tissues, several studies have shown that miR-155 is under-expressed in melanoma [ 41 , 44 ].…”

“…Furthermore, miR-155 has been implicated in the interaction between melanoma cells and the tumor microenvironment [ 26 , 33 , 72 , 80 , 81 ]. It has been shown to modulate the immune response by regulating the expression of cytokines and chemokines, which can affect the recruitment and function of immune cells in the tumor microenvironment, as will be detailed in the following subsections.…”

“…Among the different microRNAs, miR-155 is a classic example of a multifunctional miRNA that plays essential roles in regulating inflammatory response [ 21 ], autoimmunity [ 22 ], and cancer progression [ 23 , 24 ]. A large-scale miRNome analysis revealed miR-155 to be one of the top candidate markers for cancer pathogenesis [ 25 ], suggesting that miR-155 may serve as a bridge between inflammation and cancer [ 24 , 26 ]. MiR-155 is encoded by the third exon of the MIR155 host gene (MIR155HG), formerly called the B-cell Integration Cluster (BIC), located on human chromosome 21q21 [ 27 ].…”

Three Strategies in Engineering Nanomedicines for Tumor Microenvironment‐Enabled Phototherapy

“…[ 61 ] A number of miRNAs protect tumor cells from immunological response by lowering their immunogenicity as well as the anticancerous immune attack amplitude. [ 61 ] Another group of miRNAs regulate many components of the immune system, including myeloid‐derived suppressor cells (MDSCs), regulatory T cell (Treg), and dendritic cells, to promote the metastasis, invasion, and angiogenesis of cancer. The interactions of these immune cells with miRNAs have been summarized in recent reviews.…”