Ethnopharmacological relevance: Jianpi Huayu decoction (JHD) is a traditional Chinese medicinal preparation used to treat a variety of malignant tumors including HCC, although the underlying mechanism remains unknown. Exosomes in the tumor microenvironment mediate intercellular signaling among cancer cells, but precise contributions to hepatocellular carcinoma (HCC) progression are still elusive.
Aim of the study: In this work, the main objective was to examine the mechanisms underlying anti-tumor effects of JHD and the potential contributions of exosomal signaling.
Materials and methods: LC-MS/MS was used for quality control of JDH preparation, while nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM) and western blotting were used for verification of exosomes. In vitro assays included CCK8, wound healing assay, transwell invasion assay, qRT-PCR and western blotting were performed to investigate the effects of JHD on HCC cells and the molecular mechanism. Furthermore, the effects of JHD on subcutaneous tumor model of nude mice were also determined.
Results: JHD inhibited the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of cultured HCC cells. Further, exosomes isolated from EMT-induced HCC cells promoted the migration, invasion and EMT of other cultured HCC cells, while exosomes isolated from EMT-induced HCC cells after JHD treatment had little effect. In addition, JHD reduced the expression of exosomal miR-23a-3p in cultured HCC cells. miR-23a-3p was significantly up-regulated in tumor compared with that in adjacent non-cancerous tissues of patients with HCC. HCC patients with high miR-23a-3p expression had poor overall survival after hepatectomy. Meanwhile, miR-23a-3p enhanced HCC cell proliferation, EMT, and expression of Smad signaling proteins. More importantly, overexpression of miR-23a-3p can reverse the inhibition of EMT and Smad signaling pathway caused by JHD treatment. In vivo assays, treatment with JHD also reduced the growth of HCC-derived tumors in nude mice, reduced the expression of miR-23a-3p in serum exosomes and the level of EMT in tumor cells.
Conclusions: the antitumor effects of JHD on HCC are mediated at least in part by inhibition of EMT due to downregulation of exosome-mediated intercellular miR-23a-3p transfer and subsequent blockade of Smad signaling. Disrupting this exosomal miR-23a-3p/Smad signaling pathway may be an effective treatment.
Keywords: Epithelial mesenchymal transition; Exosome; Hepatocellular carcinoma; Jianpi huayu decoction; miR-23a-3p.
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