Engineered exosomes loaded with miR-494-3p suppress homologous ovarian cancer

Objective: Ovarian cancer (OC) is a malignant tumor that endangers women's health. We intend to develop engineered exosomes to deliver the suppressor microRNA to inhibit the growth and progression of OC. Methods The level of miR-494-3p in OC tissues and cell lines was detected by qRT-PCR. Exosomes secreted by OC cells were isolated and loaded with miR-494-3p by electroporation to prepare the engineered exosomes miR-494-3p Exo. The morphology and size of miR-494-3p Exo were identified using the Transmission Electron Microscope and Nanoparticle Tracing Analysis. Western blot (WB) was conducted to detect the exosomal markers TSG101 and CD63. The loading efficiency was assessed by qRT-PCR. Exosomes labelled with PKH26 were used to study the specific uptake by OC cells. OVCAR3 and SKOV3 cells were treated with PBS, Unload Exo and miR-494-3p Exo, respectively. EdU assay was conducted to evaluate proliferation, flow cytometry to detect apoptosis, scratching assay to evaluate migration, Transwell assay to evaluate migration and invasion. And the levels of apoptosis-, migration- and invasion-related proteins were assessed by WB. Results MiR-494-3p was expressed at a low level in OC tissues and cell lines. Engineered exosomes loaded with miR-494-3p with an average size of 30–120 nm were successfully prepared, and can be specifically absorbed by OVCAR3 and SKOV3 cells. MiR-494-3p Exo can inhibit the proliferation, migration and invasion of OVCAR3 and SKOV3 cells and promote apoptosis. Conclusions MiR-494-3p-loaded engineered exosomes can inhibit homologous OC cells.