Objective: To investigate the effect of human umbilical vein endothelial cell-derived extracellular vesicles (HUVEC-EVs) on proliferation and migration of human breast cancer cells and its potential mechanisms.  Methods: Different concentrations of HUVEC-EVs (0, 10, 20 and 40 μg/mL) were used to treat MDA-MB-231 and MCF-7 breast cancer cells for 24 h, the proliferation was detected by MTT assay and plate clone formation assay. Transwell assay was used to detect the migration and invasion, scratch wound assay was used to detect the migration and Western blotting was to detect related protein expression of JAK2/STAT3 signaling pathway. Results: Compared with 0 μg/mL HUVEC-EVs, 10, 20 and 40 μg/mL HUVEC-EVs improved the proliferation, plate cloning and migration of MDA-MB-231 and MCF-7 cells significantly (P<0.05); there was no significant difference in total JAK2 and STAT3 protein expression (P>0.05), while the expression of p-JAK2 and p-STAT3 protein increased markedly(P<0.05). Conclusion: HUVEC-EVs may promote breast cancer cell proliferation and migration through the phosphorylation of JAK2/STAT3 signaling pathway.

［Key words］human umbilical vein endothelial cells; extracellular vesicles; breast cancer; JAK2/STAT3 pathway