Cancer stem cells (CSCs) are important factors contributing to tumorigenesis. We examined whether CSCs isolated from colorectal cancer (CRC) cells possess metastatic properties that can be transferred to non-CSCs via the delivery of miR-200c enclosed in extracellular vesicles (EVs). The inhibitory effect of atractylenolide I (ATL-1), a traditional Chinese medicinal compound, on miR-200c activity and metastatic transfer was investigated. EVs were isolated from colorectal CSCs. The expression of miR-200c was evaluated in CSCs and CSC-derived EVs, and horizontal transfer of metastatic properties via EVs to non-CSCs was investigated in terms of cell behavior and phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling. CSCs isolated from metastatic CRC cells exhibited higher levels of miR-200c than those in nonmetastatic CRC cells. Overexpression of miR-200c in CSCs enhanced metastatic potential by promoting proliferation and inhibiting apoptosis, in turn leading to the release of EVs carrying an excess of miR-200c. Non-CSCs co-cultured with miR-200c-containing EVs exhibited enhanced invasion and stemness maintenance associated with PI3K/Akt/mTOR activation, demonstrating successful metastatic transfer via EV delivery. Furthermore, ATL-1 impaired the EV-mediated transfer of metastatic properties by suppressing miR-200c activity and disrupting EV uptake by non-CSCs. EVs are critical signal transducers that facilitate intercellular communication and exchange of metastatic properties, which can be controlled by ATL-1. The findings are useful in the development of microRNA-based anticancer strategies by targeting EV-mediated activity, especially using natural compounds.
Keywords: PI3K/Akt/mTOR; atractylenolide I; extracellular vesicles; metastasis; stemness.
© 2020 The Authors. Clinical and Translational Medicine published by John Wiley & Sons Australia, Ltd on behalf of Shanghai Institute of Clinical Bioinformatics.