miR-18a-5p derived from mesenchymal stem cells-extracellular vesicles inhibits ovarian cancer cell proliferation, migration, invasion, and chemotherapy resistance

OBJECTIVE: Ovarian cancer (OC) is a major threat to women’s health. Mesenchymal stem cells (MSCs) are key regulators in cellular communication by secreting extracellular vesicles (EVs) that are involved in OC. This study probed into the mechanism of human MSCs derived-EVs (hMSC-EVs) in regulating OC cell growth and chemotherapy resistance. METHODS: hMSCs and EVs were isolated and identified. After adding EVs, the uptake of EVs by OC CAOV3/ES2 cells (for in vitro studies), and cell proliferation, migration, and invasion were detected. Downregulated miRNAs in hMSC-EVs were screened and miR-18a-5p expression in OC patients was detected. The prognosis of OC patients was analyzed. Binding sites of miR-18a-5p and NACC1 were predicted and validated. NACC1 expression in OC tissues was measured by RT-qPCR, and its correlation with miR-18a-5p was analyzed by Pearson method. AKT/mTOR pathway activation was assessed by WB. The cisplatin sensitivity of EVs-treated CAOV3 cells was evaluated via MTT assay and tested by tumor formation assay in nude mice. RESULTS: hMSC-EVs suppressed OC cell proliferation, migration, and invasion. miR-18a-5p was downregulated in OC and miR-18a-5p low expression was associated with a poor prognosis. EV-encapsulated miR-18a-5p targeted NACC1. NACC1 was upregulated in OC tissues. miR-18a-5p knockdown and NACC1 overexpression both annulled the inhibition of hMSC-EVs on OC cell growth. AKT and mTOR were elevated in OC and NACC1 activated the AKT/mTOR pathway in OC cells. hMSC-EVs promoted cisplatin sensitivity of OC cells by carrying miR-18a-5p. CONCLUSION: hMSC-EVs-derived miR-18a-5p inhibits OC cell proliferation, migration, invasion, and chemotherapy resistance. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12967-022-03422-7.