Extracellular vesicle-mediated delivery of miR-127-3p inhibits the proliferation and invasion of choriocarcinoma cells by targeting ITGA6.

Background: Choriocarcinoma (CC) is a highly aggressive malignant tumor that mostly occurs in women of childbearing age. Chemotherapy is the main treatment for CC, but it has side effects and causes drug resistance, which can lead to treatment failure. Extracellular vesicles (EVs) that deliver microRNAs (miRNAs) have emerged as a novel and promising therapeutic tool for inhibiting tumor progression and metastasis. This research aimed to study the effects of miR-127-3p-enriched EVs (EV-miR-127-3p) on CC and underlying mechanisms.

Methods: Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blotting were performed to determine the miR-127-3p and integrin subunit alpha-6 (ITGA6) expression levels. The interaction between miR-127-3p and ITGA6 was confirmed by a dual-luciferase reporter assay. Human umbilical cord mesenchymal stem cells (hUCMSCs) were identified using flow cytometry and multilineage differentiation. Uptake of labeled EVs was demonstrated using immunofluorescence staining and flow cytometry assays. EV-miR-127-3p were isolated from the culture medium of hUCMSCs and co-cultured with JEG-3 or JAR cells to evaluate their effects on cell proliferation, invasion, migration, and apoptosis, using the cell counting kit-8, Transwell, and flow cytometry assays. Epithelial-mesenchymal transition (EMT) and the transforming growth factor (TGF)-β1/Smad pathway were investigated using qRT-PCR and western blotting.

Results: The expression of miR-127-3p was downregulated, while that of ITGA6 was upregulated in CC cell lines. ITGA6 was identified as a target gene of miR-127-3p. EV-miR-127-3p could inhibit the proliferation, invasion, migration, and promote the apoptosis of CC cells. We observed that EV-miR-127-3p suppressed EMT of CC cells by targeting ITGA6. In addition, the knockdown of ITGA6 inhibited the TGF-β1/Smad pathway and reversed the EMT-promoting effect.

Conclusion: These results indicate that EV-miR-127-3p from hUCMSCs exhibits anti-tumor effects by targeting ITGA6, which may be used as a novel therapeutic strategy for CC treatment.