MiR-199a-modified exosomes from adipose tissue-derived mesenchymal stem cells improve hepatocellular carcinoma chemosensitivity through mTOR pathway
Guohua Lou, Liang Chen, Caixia Xia, Weina Wang, Jinjin Qi, Aichun Li, Liying Zhao, Zhi Chen, Min Zheng, Yanning Liu
Abstract
BACKGROUND: MiR-199a-3p (miR-199a) can enhance the chemosensitivity of hepatocellular carcinoma (HCC). Because of the easy degradation of miRNA by direct infusion, effective vehicle-mediated delivery of miR-199a may represent a new strategy for improving HCC chemotherapy. Considering mesenchymal stem cell (MSC)-derived exosomes as promising natural nanovectors for drug and molecule delivery, we aimed to determine whether exosomes from adipose tissue-derived MSCs (AMSCs) could be used to deliver miR-199a and improve HCC chemosensitivity. METHODS: MiR-199a-modified AMSCs (AMSC-199a) were constructed by miR-199a lentivirus infection and puromycin selection. MiR-199-modified exosomes (AMSC-Exo-199a) were isolated from the supernatant of AMSC-199a and were assessed by transmission electron microscopy, nanoparticle tracking analysis, and flow cytometry analysis. The expression levels of miR-199a in HCC samples, AMSCs, exosomes, and HCC cells were quantified by real-time PCR. The effects of AMSC-Exo-199a on HCC chemosensitivity were determined by cell proliferation and apoptosis assays and by i.v. injection into orthotopic HCC mouse models with doxorubicin treatment. MTOR, p-4EBP1 and p-70S6K levels in HCC cells and tissues were quantified by Western blot. RESULTS: AMSC-Exo-199a had the classic characteristics of exosomes and could effectively mediate miR-199a delivery to HCC cells. Additionally, AMSC-Exo-199a significantly sensitized HCC cells to doxorubicin by targeting mTOR and subsequently inhibiting the mTOR pathway. Moreover, i.v.-injected AMSC-Exo-199a could distribute to tumor tissue and markedly increased the effect of Dox against HCC in vivo. CONCLUSIONS: AMSC-Exo-199a can be an effective vehicle for miR-199a delivery, and they effectively sensitized HCC to chemotherapeutic agents by targeting mTOR pathway. AMSC-Exo-199a administration may provide a new strategy for improving HCC chemosensitivity.