In vitro and in vivo anti-metastatic effect of the alkaliod matrine from Sophora flavecens on hepatocellular carcinoma and its mechanisms

Backgrounds: Hepatocellular carcinoma (HCC) is one of the most prevalent and lethal cancer with high metastasis and recurrence rates. Hypoxia-induced miRNAs and HIF-1 alpha are demonstrated to play essential roles in tumor metastasis. Matrine (C15H24N2O), an alkaloid extracted from Sophora flavescens Aiton, has been used as adjuvant therapy for liver cancer in China. The anti-metastasis effects of matrine on HCC and the underlying mechanisms remain poorly understood. Purpose: We aimed to investigate the effects of matrine on metastasis of HCC both in vitro and in vivo, and explored whether miR-199a-5p and HIF-1 alpha are involved in the action of matrine. Methods: MTT method, colony formation, wound healing and matrigel transwell assays were performed to evaluate the effects of matrine on cell proliferation, migration and invasion. Nude mice xenograft model and immunohistochemistry (IHC) assay were employed to investigate the anti-metastatic action of matrine in vivo. Quantitative real-time PCR, western blot and dual luciferase reporter assay were conducted to determine the underlying mechanisms of matrine. Results: Matrine exerted stronger anti-proliferative action on Bel7402 and SMMC-7721 cells under hypoxia than that in normoxia. Both matrine and miR-199a-5p exhibited significant inhibitory effects on migration, invasion and EMT in Bel7402 and SMMC-7721 cells under hypoxia. Further study showed that miR-199a-5p was downregulated in HCC cell lines, and this microRNA was identified to directly target HIF-1 alpha, resulting in decreased HIF-1 alpha expression. Matrine induced miR-199a-5p expression, decreased HIF-1 alpha expression and inhibited metastasis of Bel7402 and SMMC-7721 cells, while miR-199a-5p knockdown reversed the inhibitory effects of matrine on cell migration, invasion, EMT and HIF-1 alpha expression. In vivo, matrine showed significant anti-metastatic activity in the nude mouse xenograft model. H&E and IHC analysis indicated that lung and liver metastasis nodules were reduced, and the protein expression of HIF-1 alpha and Vimentin were significantly decreased by i.p injection of matrine. Conclusions: Matrine exhibits significant anti-metastatic effect on HCC, which is attributed to enhanced miR-199a-5p expression and subsequently impaired HIF-1 alpha signaling and EMT. These findings suggest that miR-199a-5p is a potential therapeutic target of HCC, and matrine may represent a promising anti-metastatic medication for HCC therapy.