Exosomal Micro RNA-107 Reverses Chemotherapeutic Drug Resistance of Gastric Cancer Cells Through HMGA2/mTOR/P-gp Pathway
Abstract Background: RNA cargo in exosomes,especially microRNAs (miRNAs), play an important role in the chemotherapy drug resistance of human cancers. However, the role and mechanism of exosomal miR-107 on multidrug resistance of gastric cancer cells was still not clear. In this study, we sought to explore whether exosomal miR-107 could reverse theresistance of gastric cancer cells to the chemotherapy drugs. Methods: We extracted exosomes from sensitive (SGC-7901, MGC-803) and resistant (SGC-7901/5-FU) gastric cancer cells by ultracentrifugation and the isolated exosomes were identified using transmission electron microscopy (TEM) and dynamic light scattering analysis (DLS). The expression of miR-107 and high mobility group A2 (HMGA2) were detected by real-time quantitative PCR (RT-qPCR). MTT assay was used to investigate the effect of exosomes on gastric cancer cells growth in vitro. The uptake of exosomes by recipient cells were observed using a fluorescence microscope. The predicted target relationship between miR-107 and HMGA2 was verified by gauss-luciferase reporter assay. The expression of HMGA2, p-mTOR/mTOR, P-gp and other exosomal indicated marker proteins were detected by western blot. Results: Our results indicated that the isolated exosomes were demostrated typically cup-like lipid bilayer membrans structure. SGC-7901/5-FU cells were cross-resistant to chemotherapy drug cisplatin (DDP), and the sensitive cells-secreted exosomes drastically reversed the resistance of the resistant gastric cells to the chemotherapeutic drugs,which was verificated by exosomal inhibitor GW4896. Mechanistically, the reversal effect were mainly mediated by exosome-secreted miR-107 through downregulating the expression of targert molecular HMGA2, and inhibiting HMGA2/mTOR/P-gp pathway, which were proofed by luciferase reporter assay and rescue assay. Conclusions: These findings demonstrated that exosome-transmitted miR-107 significantly enhanced the sensitivity of resistant gastric cancer cells to chemotherapeutic agents by mediating the HMGA2/mTOR/P-gp axis and appling exosomal miR-107 may be a novel target in gastric cancers treatment.