Harnessing extracellular vesicles for innovative immunotherapy for cancer treatment

Extracellular vesicles (EVs) are emerging as a significant immune communication regulator within the tumor microenvironment, representing a potential tool for cancer immunotherapy. Since EVs are nanosized, they carry tumor antigens, MHC, checkpoint proteins, cytokines, and regulatory RNAs, thus enabling them to modulate both innate as well as adaptive immune responses. Tumor-derived exosomes play a major role by helping cancer evade the immune system. They mess with T cell function, push myeloid-derived suppressor cells to expand, and steer tumor-associated macrophages towards immunosuppressive roles. On the flip side, exosomes from immune cells, dendritic cells (DCs), B- and T-lymphocytes, natural killer (NK) cells, mast cells, and neutrophils actually boost the immune response. They strengthen antigen presentation, fire up cytotoxic lymphocytes, and drive Th-1 antitumor immunity. This review explores how exosomes, depending on their origin, shape the immune landscape. It looks closer at their molecular cargo and how these small vesicles influence immune surveillance and tumor growth. The evidence from animal studies stand out, such as exosome-based cancer vaccines, especially those from DCs loaded with tumor antigens, which trigger strong CD8 + T cell response and slow down tumor progression. Beyond therapy, exosomes have started emerging as biomarkers. As they are stable and capable of carrying tumor-specific molecules, they help in tracking immune activity, measuring treatment success, and monitoring disease as it develops. This review also tackles key exosomal targets such as programmed death ligand-1 (PD-L1), transforming growth factor-beta (TGF)-β, and immunoregulatory miRNAs that suppress immunity, pointing to ways to make cancer immunotherapy work better. The review sums things up by looking at current clinical trials testing exosome-based immunotherapies and the hurdles ahead including EV heterogeneity, scaling up production of EVs, and standardizing cargo. Altogether, this review underscores the significance of exosomes, not just as molecular messengers, but as promising tools and targets in the future of cancer immunotherapy.