Fig. 4

Biogenesis and release of exosomes containing miR-155. Exosomes are nano-sized extracellular vesicles (40–100 nm) formed within multivesicular bodies (MVBs) through inward budding of endosomal membranes. Upon fusion of MVBs with the plasma membrane, exosomes are released into the extracellular space. They are enriched in lipids, proteins, and nucleic acids, including microRNAs such as miR-155. These vesicles can be taken up by nearby or distant recipient cells, enabling intercellular communication. The figure illustrates how exosomes derived from tumor or immune cells serve as carriers of miR-155, modulating gene expression in target cells and contributing to tumor angiogenesis and progression