Human umbilical cord mesenchymal stem cells-derived exosomes deliver microRNA-375 to downregulate ENAH and thus retard esophageal squamous cell carcinoma progression

BACKGROUND: Exosomal microRNAs (miRNAs or miRs) from bone marrow-derived mesenchymal stem cells (UCMSCs) have emerged as promising therapeutic strategies for cancer treatment. The current study aimed to elucidate the underlying mechanism of human umbilical cord mesenchymal stem cells (hUCMSCs)-derived exosomal miR-375 in esophageal squamous cell carcinoma (ESCC). METHODS: After determining the expression of miR-375 and its putative target enabled homolog (ENAH) in ESCC tissues and cells, we tested effects of their altered expression on ESCC proliferation, invasion, migration, and tumorsphere formation was subsequently measured. Transfected hUCMSCs-derived exosomes (hUCMSCs-exo) were isolated and co-cultured with ESCC cells to measure the effects of miR-375 delivered by hUCMSCs-exo on ESCC development. Finally, we investigated the effect of miR-375 on tumor growth in vivo. RESULTS: The expression of miR-375 was reduced, while the expression of ENAH was elevated in ESCC. ENAH was identified as a target gene of miR-375. Elevated miR-375 or depleted ENAH expression inhibited ESCC cell proliferation, invasion, migration, tumorsphere formation, and promoted apoptosis. Moreover, miR-375 delivered by hUCMSCs-exo could suppress ESCC cell proliferation, invasion, migration, tumorsphere formation, but promoted apoptosis in vitro, as well as inhibiting tumor growth in vivo. CONCLUSIONS: Taken together, hUCMSCs-exo can deliver miR-375 to suppress ENAH expression and subsequently inhibit the initiation and progression of ESCC.