Extracellular vesicles carrying miRNA-181b-5p affects the malignant progression of acute lymphoblastic leukemia

To investigate how serum extracellular vesicles (EVs)-carried miRNA-181b-5p affected the proliferation, cell cycle and apoptosis of acute lymphoblastic leukemia (ALL) cells. Differentially expressed miRNAs related to ALL were screened by bioinformatics analysis, and the localization of target miRNA was searched by its expression. qRT-PCR was adopted to confirm the expression of miRNA-181b-5p. Flow cytometry and fluorescence microscopy were applied to evaluate EVs internalization. MTT assay was employed to verify the proliferation of ALL cells. Cell cycle and apoptosis were analyzed by flow cytometry. Transwell assay was applied to evaluate migration and invasion abilities. High expression of miRNA-181b-5p was proved in ALL cell lines, and miRNA-181b-5p enriched in the exosomes and vesicles of blood cells. In the meantime, it was found that EVs carrying miRNA-181b-5p could be internalized by ALL cells and thus the expression of miRNA-181b-5p was up-regulated. Cell function assays showed that the proliferation, migration, invasion abilities of ALL cell lines were promoted in miRNA-181b-5p mimic group or the group co-culturing ALL-derived EVs and BALL-1 cell lines. The percentage of cells in G0/G1 phase was reduced and cell apoptosis was also inhibited. miRNA-181b-5p carried by EVs in peripheral blood of ALL patients can enter ALL cells and thus promote the malignancy of ALL cells.