The Impact of Extracellular Vesicle-Encapsulated Circulating MicroRNAs in Lung Cancer Research

Figure 1

MiRNA release mechanisms into extracellular space. Precursor miRNAs are processed by ribonuclease Dicer to mature double-stranded miRNAs (miRNA duplex). One strand of the miRNA duplex is selectively loaded into the RNA-induced silencing complex (RISC), which contains the Argonaute (AGO) family protein as a core component. A fraction of miRNAs are released from living cells into the extracellular environment via the following mechanisms: (1) sorting into multivesicular bodies (MVB) and secretion via exosomes, (2) incorporating into microvesicles that are formed by the outward shedding of the plasma membrane, (3) associating with RNA-binding proteins, such as AGO2 and release of the miRNA-AGO complexes, and (4) exporting and incorporating into high-density lipoprotein (HDL) particles. Extracellular vesicle miRNAs are possibly involved in cell-cell communication.