Exosomes function as nanoparticles to transfer miR-199a-3p to reverse chemoresistance to cisplatin in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a frequently seen malignant tumor globally. The occurrence of cisplatin (DDP) resistance is one of the main reasons for the high mortality of HCC patients. Therefore, it is of great theoretical significance and application value to explore the mechanism of chemotherapy resistance. Drug resistance can be modulated by exosomes containing mRNAs, micro RNAs (miRNAs) and other non-coding RNA (ncRNAs). Exosomal miR-199a-3p (Exo-miR-199a-3p) was subjected to extraction and verification. Whether exo-miR-199a-3p could make HCC cells sensitive to DDP in vitro was verified via flow cytometry, Cell Counting Kit-8 (CCK-8) assay, immunofluorescence assay and Transwell assay. Intravenous injection of exo-miR-199a-3p and intraperitoneal injection of DDP were carried out in vivo. Moreover, the possible targets of miR-199a-3p were screened through bioinformatics analysis, which were ascertained by Western blotting (WB). Then, miR-199a-3p levels in human normal liver epithelial cell line HL-7702 and HCC cell lines HuH7 and HuH7/DDP were elevated in a concentration-dependent manner. Exo-miR-199a-3p has abilities to adjust underlying targets and conjugate cells, to repress cells to invade, stimulate their apoptosis and abate their ability. Additionally, the caudal injection of exo-miR-199a-3p reversed the chemoresistance of tumors and slowed down their growth in the body owing to the up-regulation of miR-199a-3p and down-regulation of underlying target proteins in tumors. Finally, exo-miR-199a-3p was found to overturn the HCC's resistance to DDP, and it may function in DDP-refractory HCC therapy as an underlying option in the future.