Exosome-Derived microRNA: Implications in Melanoma Progression, Diagnosis and Treatment

SIMPLE SUMMARY: Melanoma is a malignant and invasive cancer with high mortality and poor prognosis, and the incidence is increasing yearly. However, the current therapy options for melanoma are still insufficient and challenging. Recently, exosomes as essential intercellular messengers are receiving great interest for their important roles in melanoma progression, diagnosis, and treatment. Especially, the miRNAs derived from the exosomes are crucial during this process. Here, we summarized the miRNAs derived from melanoma exosomes, and analyzed their function in the progression of melanoma, including invasion and metastasis, microenvironment establishment, angiogenesis, and immune escape. In addition, we also listed the potential miRNAs including exosomal miRNAs as diagnostic markers for melanoma and introduced new therapeutic strategies for melanoma based on miRNAs and exosomes. ABSTRACT: Melanoma is a malignant and aggressive cancer, and its progression is greatly affected by interactions between melanoma cells and their surroundings. Exploration on mechanism of melanoma and improved diagnostic and therapeutic strategies are becoming increasingly important. Unlike extracellular messengers that mainly work on targeted cells through corresponding receptors, exosomes are essential intercellular messengers that deliver biologically active substances such as nucleic acids and proteins to target cells for cell–cell communication. Of them, microRNAs (miRNAs) are common and important exosomal components that can regulate the expression of a wide range of target genes. Accordingly, exosome-derived miRNAs play a significant role in melanoma progression, including invasion and metastasis, microenvironment establishment, angiogenesis, and immune escape. MiRNA signatures of exosomes are specific in melanoma patients compared to healthy controls, thus circulating miRNAs, especially exosomal miRNAs, become potential diagnostic markers and therapeutic targets for melanoma. This review aims to summarize recent studies on the role of exosomal miRNAs in melanoma as well as ongoing efforts in melanoma treatment.