The role of melanoma-derived exosomes in metastasis: Challenges and opportunities

Melanoma, a highly aggressive skin cancer, is characterized by its strong metastatic potential and resistance to standard treatments. Recent cancer research has emphasized the significance of exosomes, a type of extracellular vesicle and particle, in mediating cell-to-cell communication and driving tumor progression. Melanoma-derived exosomes contribute to metastasis by facilitating immune evasion, modulating the tumor microenvironment, and inducing epithelial-to-mesenchymal transition. The exosomal cargos, including nucleic acids (DNA, microRNA, long noncoding RNA, and circular RNA), proteins, lipids, and other biomolecules, play critical roles in reprogramming recipient cells to support tumor growth and spread. These exosomes also aid in forming pre-metastatic niches by transferring pro-inflammatory cytokines, extracellular matrix remodeling enzymes, and angiogenic factors to distant organs, preparing these sites for tumor colonization. Furthermore, tumor-derived exosomes promote therapy resistance by delivering drug-resistant molecular signatures, which diminish treatment efficacy. This emerging evidence highlights the therapeutic potential of exosome-based strategies, including inhibitors of exosome biogenesis and uptake or the use of engineered exosomes for targeted drug delivery. Advances in precision medicine also facilitate the use of exosome-derived molecular signatures in early-stage diagnosis and treatment monitoring through liquid biopsy. However, clinical translation remains challenging due to cargo heterogeneity, lack of standardized isolation methods, and potential off-target effects in exosome-based therapies. Addressing these challenges could lead to more effective therapies and better patient outcomes. This review synthesizes current knowledge on the biogenesis, composition, and functional roles of tumor-derived exosomes in metastasis, alongside their potential applications as biomarkers and therapeutic strategies. Deciphering exosomal dynamics in melanoma may open new avenues for advanced diagnostics and treatments.