Tumour metastasis is the major cause of breast cancer mortality. Myricetin, a natural polyphenol, is found in teas, wines, and berries. The pharmacodynamic action and molecular mechanism of myricetin on breast cancer metastasis remain unknown. Here, we investigated the effect of myricetin on MDA-Mb-231Br cell viability, migration, invasion, and 4T1 mouse lung metastasis mouse models. MMP-2/9 protein expression and ST6GALNAC5 expression were analysed using western blot assays and quantitative real-time polymerase chain reaction, respectively. Cell migration and invasion were detected by wound-healing and Boyden transwell assays. The antimetastatic effect in vivo was evaluated by lung metastasis model. Myricetin significantly decreased the activities of MMP-2/9 and mRNA levels of ST6GALNAC5. In addition, the migration, invasion, and adhesion were effectively inhibited in a concentration-dependent manner. On the other hand, mice treated with myricetin exhibited smaller tumour nodules compared with the vehicle mice, with only 17.78 ± 15.41% after treatment with 50 mg/kg myricetin. In conclusion, myricetin could significantly block invasion of MDA-Mb-231Br cells through suppressing the protein expression of MMP-2/9 and the expression of ST6GALNAC5, as well as lung metastasis in a mouse model, which suggests that myricetin should be developed as a potential therapeutic candidate for breast cancer.

Metastatic cancers are the main cause of cancer-related death. In breast primary cancer, the five-year survival rate is close to 100%; however, for metastatic breast cancer, that rate drops to a mere 25%, due in part to the paucity of effective therapeutic options for treating metastases. Several in vitro and in vivo studies have indicated that consumption of natural polyphenols significantly reduces the risk of cancer metastasis. Therefore, this review summarizes the research findings involving the molecular mechanisms and metabolomics of natural polyphenols and how they may be blocking breast cancer metastasis. Most natural polyphenols are thought to impair breast cancer metastasis through downregulation of MMPs expression, interference with the VEGF signaling pathway, modulation of EMT regulator, inhibition of NF-κB and mTOR expression, and other related mechanisms. Intake of natural polyphenols has been shown to impact endogenous metabolites and complex biological metabolic pathways in vivo. Breast cancer metastasis is a complicated process in which each step is modulated by a complex network of signaling pathways. We hope that by detailing the reported interactions between breast cancer metastasis and natural polyphenols, more attention will be directed to these promising candidates as effective adjunct therapies against metastatic breast cancer in the clinic.

Background: Cancer cachexia is a severe condition that leads to the death of advanced cancer patients, and approximately 50~80% of cancer patients have cancer cachexia. Ginseng extract has been reported to have substantial anticancer and immune-enhancing effects; however, no study has reported the use of ginseng alone to treat cancer cachexia. Our study's purpose was to investigate the therapeutic effects of ginseng-related monomers or mixtures on a cancer cachexia mouse model. Methods: We selected BALB/c mice and injected the mice subcutaneously with C26 colon cancer cells to construct a cancer cachexia experimental animal model. The water extract of ginseng (WEG), two types of ginseng extracts (ginsenosides at doses of 5 mg/kg (GE5) and 50 mg/kg (GE50)) and ginsenoside Rb1 (Rb1) were used to treat cancer cachexia mice. Enzyme-linked immunosorbent assays (ELISAs) were used to analyze the inhibitory effects on two key inflammatory cytokines, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Results: Our experimental results show that GE5, GE50 and Rb1 significantly reduced the levels of TNF-α (P < 0.01) and IL-6 (P < 0.01), which are closely related to cancer cachexia; however, WEG, GE5, GE50 and Rb1 did not significantly improve the gastrocnemius muscle weight or the epididymal fat weight of mice with cancer cachexia. Conclusions: These results indicate that GE5, GE50 and Rb1 may be useful for reducing symptoms due to inflammation by reducing the TNF-α and IL-6 cytokine levels in cancer cachexia mice, thereby ameliorating the symptoms of cancer cachexia. Our results may be beneficial for future studies on the use of Chinese herbal medicines to treat cancer cachexia.

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