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-1α 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-1α 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-1α, resulting in decreased HIF-1α expression. Matrine induced miR-199a-5p expression, decreased HIF-1α 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-1α 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-1α 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-1α 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.

[Matrine suppresses stemness of hepatocellular carcinoma cells by regulating ß-catenin signaling pathway].

OBJECTIVE: To explore the effects of matrine on the proliferation, tumor cell stemness, ß-catenin transcriptional activity and AKT/GSK3ß/ß-catenin signaling pathway in human hepatocellular carcinoma (HCC) HepG2 and Huh7 cells. METHODS: The proliferation and colony formation ability of HepG2 and Huh7 cells treated with 200, 400, and 800 µg/mL matrine were evaluated with MTT assay and colony formation assay, respectively. Real-time quantitative PCR was performed to detect the mRNA expressions of CD90, epithelial cell adhesion molecule (EpCAM) and CD133, and dual-luciferase assay was used to detect the transcriptional activity of ß-catenin in the treated cells. The effects of matrine on the expressions of protein kinase B (AKT), P-AKT, GSK-3ß, P-GSK-3ß, P-ß-catenin and ß-catenin proteins in the Wnt/ß-catenin signaling pathway were assessed using Western blotting. RESULTS: Matrine inhibited the proliferation of the two HCC cell lines in a time- and concentration-dependent manner. The half-inhibitory concentrations of matrine were 2369, 1565 and 909.1 µg/mL at 24, 48 and 72 h in HepG2 cells, respectively, and were 1355, 781.8, and 612.8 µg/mL in Huh7 cells, respectively. Matrine concentrationdependently suppressed colony formation of the HCC cells, producing significant inhibitory effects at 400 µg/mL P < 0.01) and 800 µg/mL P < 0.001) in HepG2 cells and at 200 µg/mL P < 0.05), 400 µg/mL P < 0.01), and 800 µg/mL P < 0.001) in Huh7 cells. Matrine at 400 and 800 µg/mL significantly inhibited the mRNA expression of CD90, EpCAM and CD133 and the transcriptional level of ß-catenin in both HepG2 and Huh7 cells P < 0.05 or 0.01). Matrine at 400 and 800 µg/mL also significantly decreased the protein levels of ß-catenin, P-AKT and P-GSK-3ß and increased the phosphorylation level of ß-catenin in both of the cell lines. CONCLUSIONS: Matrine inhibits the proliferation, colony formation, and the expressions of tumor stem cell markers CD90, EpCAM and CD133 in both HepG2 and Huh7 cells probably by inhibiting Wnt/ß-catenin signaling pathway and the transcriptional activity ofß-catenin.

Myricetin antagonizes semen-derived enhancer of viral infection (SEVI) formation and influences its infection-enhancing activity.

BACKGROUND: Semen is a critical vector for human immunodeficiency virus (HIV) sexual transmission and harbors seminal amyloid fibrils that can markedly enhance HIV infection. Semen-derived enhancer of viral infection (SEVI) is one of the best-characterized seminal amyloid fibrils. Due to their highly cationic properties, SEVI fibrils can capture HIV virions, increase viral attachment to target cells, and augment viral fusion. Some studies have reported that myricetin antagonizes amyloid ß-protein (Aß) formation; myricetin also displays strong anti-HIV activity in vitro. RESULTS: Here, we report that myricetin inhibits the formation of SEVI fibrils by binding to the amyloidogenic region of the SEVI precursor peptide (PAP248-286) and disrupting PAP248-286 oligomerization. In addition, myricetin was found to remodel preformed SEVI fibrils and to influence the activity of SEVI in promoting HIV-1 infection. Moreover, myricetin showed synergistic effects against HIV-1 infection in combination with other antiretroviral drugs in semen. CONCLUSIONS: Incorporation of myricetin into a combination bifunctional microbicide with both anti-SEVI and anti-HIV activities is a highly promising approach to preventing sexual transmission of HIV.

Trilobatin as an HIV-1 entry inhibitor targeting the HIV-1 Gp41 envelope.

HIV-1 transmembrane protein gp41 plays a crucial role by forming a stable six-helix bundle during HIV entry. Due to highly conserved sequence of gp41, the development of an effective and safe small-molecule compound targeting gp41 is a good choice. Currently, natural polyanionic ingredients with anti-HIV activities have aroused concern. Here, we first discovered that a glycosylated dihydrochalcone, trilobatin, exhibited broad anti-HIV-1 activity and low cytotoxicity in vitro. Site-directed mutagenesis analysis suggested that the hydrophobic residue (I564) located in gp41 pocket-forming site is pivotal for anti-HIV activity of trilobatin. Furthermore, trilobatin displayed synergistic anti-HIV activities combined with other antiretroviral agents. Trilobatin has a good potential to be developed as a small-molecule HIV-1 entry inhibitor for clinical combination therapy.