Study On The Functional Roles And Selective Transport Mechanisms Of Extracellular Vesicles MiR-122-5p

Extracellular vesicles(EVs)are membrane-structured vesicles secreted by cells,which carry a variety of bioactive molecules that can be transmitted to adjacent and distant cells,thereby triggering a variety of signal cascades in recipient cells,and thus play an important role in cell communication.More and more studies have shown that extracellular vesicular miRNAs play an important role in cancer,and they can be absorbed by target cells,thus affecting the physiological processes such as proliferation,migration,angiogenesis,metabolism and immunity of cancer cells.Currently,the role of extracellular vesicular miRNAs in tumor metastasis has attracted extensive attention.By means of high-throughput sequencing,our previous study found that plasmaderived extracellular vesicle miRNAs in patients with non-small cell lung cancer(NSCLC)were significantly different from normal samples in terms of composition and expression.On this basis,we verified the sequencing results at the cell line level.The results showed that miR-451 a and miR-122-5p were selectively entered into the extracellular vesicles,which could be used as markers for the early diagnosis of NSCLC.In this work,we compared the function of extracellular vesicles derived from human lung cancer cell A549 and human embryonic lung fibroblast IMR-90,and found that A549 extracellular vesicle can promote the migration of normal liver cells L02.Further experiments showed that the main active component in the extracellular vesicles of A549 was miR-122-5p.Therefore,our study focused on the function of extracellular vesicle miR-122-5p in the development of lung cancer and the mechanism of its selective delivery into extracellular vesicles.By detecting the epithelial–mesenchymal transition(EMT)-related proteins,we found that extracellular vesicle miR-122-5p may promote the migration of L02 by promoting the EMT process,thus creating favorable conditions for the metastasis of lung cancer to the liver.By downregulating the expression of proteins related to the selective transport of miRNAs in extracellular vesicles,we found that hnRNPA2B1 can promote the delivery of miR-122-5p into extracellular vesicles.This promotion may be due to the important role of the EXOmotif and hnRNPA2B1 recognition motifs on miR-122-5p.In conclusion,hnRNPA2B1 protein plays an important role in mediating the selective delivery of miR-122-5p into extracellular vesicles,whereas miR-122-5p,which is abnormally highly expressed in NSCLC derived extracellular vesicles,plays an important role in tumor metastasis by promoting the migration of normal cells at the metastasis sites,such as L02.In this paper,we used NSCLC extracellular vesiclederived miR-122-5p as a research object,and its intracellular function,the mechanism of selective transport of extracellular vesicles to the extracellular space and its role in recipient cells were studied in detail.This helps us to elucidate the biological function of extracellular vesicles miRNAs and provides relevant experimental evidence,which provides a new target for the early diagnosis of NSCLC.