Extracellular vesicles from highly metastatic tumor cells have been shown to mediate epithelial-mesenchymal transition (EMT)-related events in recipient cells. In endometrial epithelial cells

EMT processes are known to be involved in the development of adenomyosis. We aimed to investigate whether adenomyosis-derived extracellular vesicles (AMEVs) are able to induce an EMT process in endometrial epithelial cells. In this study

AMEVs were isolated from patients with adenomyosis and characterized by transmission electron microscopy

Western blot

and nanoparticle tracking. Primary endometrial epithelial cells (EECs) were derived from normal endometrium tissues from patients with leiomyoma and co-cultured with AMEVs

in vitro

. AMEV uptake was examined by fluorescence confocal microscopy. The invasion of EECs was confirmed by Transwell assay. Immunohistochemistry

Western blot

and qRT-PCR were performed on EECs to illustrate the expression levels of cytokeratin 19

E-cadherin

vimentin

and zinc finger E-box-binding homeobox 1 (ZEB1). The results indicated that the cellular fluorescence intensity gradually increased after 48 h of co-culture

but decreased after 72 h. After co-culturing with AMEVs for 72 h

EECs expressed significantly lower levels of cytokeratin 19 and E-cadherin

and significantly higher levels of vimentin and ZEB1. Together these results demonstrated that AMEVs induce an EMT process and enhance the invasion of EECs. These changes may contribute to the pathogenesis and progression of adenomyosis.