Scutellarin, a flavonoid compound from Scutellaria barbata, suppresses growth of breast cancer stem cells in vitro and in tumor-bearing mice.

BACKGROUND: Scutellaria barbata D. Don (SB), commonly known as Ban Zhi Lian and firstly documented by Shigong Chen, is a dried whole plant that has been studied for its therapeutic effects on breast cancer, colon cancer, and prostate cancer. Among its various compounds, scutellarin (SCU) has been demonstrated with anti-tumor effects. PURPOSE: This study aimed to evaluate the effects of SB water extract (SBW) and scutellarin on breast cancer stem cells (BCSCs), and to investigate their potential therapeutic effects on breast tumors in mice. METHODS: BCSCs were enriched from human breast cancer cells (MDA-MB-231 and MDA-MB-361) and their characteristics were analyzed. The effects of varying concentrations of SBW and scutellarin on cell viability, proliferation, self-renewal, and migration abilities were studied, along with the underlying mechanisms. The in vivo anti-tumor effects of scutellarin were further evaluated in SCID/NOD mice. Firstly, mice were inoculated with naïve BCSCs and subjected to treatment with scutellarin or vehicle. Secondly, BCSCs were pre-treated with scutellarin or vehicle prior to inoculation into mice. RESULTS: The derived BCSCs expressed CD44, CD133 and ALDH1, but not CD24, indicating that BCSCs have been successfully induced from both MDA-MB-231 and MDA-MB-361 cells. Both SBW and scutellarin reduced the viability, proliferation, sphere and colony formation, and migration of BCSCs. In mice with tumors derived from naïve BCSCs, scutellarin significantly reduced tumor growth, expression of proliferative (Ki67) and stem cell markers (CD44), and lung metastasis. In addition, pre-treatment with scutellarin also slowed tumor growth. Western blot results suggested the involvement of Wnt/ß-catenin, NF-κB, and PTEN/Akt/mTOR signaling pathways underlying the inhibitory effects of scutellarin. CONCLUSION: Our study demonstrated for the first time that both SB water extract and scutellarin could reduce the proliferation and migration of BCSCs in vitro. Scutellarin was shown to possess novel inhibitory activities in BCSCs progression. These findings suggest that Scutellaria barbata water extract, in particular, scutellarin, may have potential to be further developed as an adjuvant therapy for reducing breast cancer recurrence.

Mechanistic insights into the anti-tumor and anti-metastatic effects of Patrinia villosa aqueous extract in colon cancer via modulation of TGF-ß R1-smad2/3-E-cadherin and FAK-RhoA-cofilin pathways.

BACKGROUND: Patrinia villosa, a traditional medicinal herb commonly used for treating intestinal-related diseases, has been commonly prescribed by Chinese medicine practitioners as a key component herb to treat colon cancer, although its anti-tumor effect and mechanisms of action have not been fully elucidated. HYPOTHESIS/PURPOSE: This study aimed to investigate the anti-tumor and anti-metastatic effects of Patrinia villosa aqueous extract (PVW), and its underlying mechanisms. METHOD: The chemical profile of PVW was analysed by high-performance liquid chromatography with photodiode-array detection (HPLC-DAD) method. Cell-based functional assays MTT, BrdU, scratch, and transwell were conducted to evaluate the effects of PVW on human colon cancer HCT116 and murine colon26-luc cells, assessing cytotoxicity, cell proliferation, motility, and migration, respectively. Western blotting was performed to assess the effect of PVW on the expression of key intracellular signaling proteins. In vivo studies were conducted using zebrafish embryos and tumor-bearing mice to evaluate the anti-tumor, anti-angiogenesis, and anti-metastatic effects of PVW in colon cancer. RESULTS: Five chemical markers were identified and quantified in PVW. PVW exhibited significant cytotoxicity and anti-proliferative activity, as well as inhibitory effects on cell motility and migration in both HCT116 and colon 26-luc cancer cells via modulating protein expressions of TGF-ß R1, smad2/3, snail, E-cadherin, FAK, RhoA, and cofilin. PVW (0.01-0.1 mg/ml) could significantly decrease the length of subintestinal vessels of zebrafish embryos through decreasing mRNA expressions of FLT1, FLT4, KDRL, VEGFaa, VEGFc, and Tie1. PVW (> 0.05 mg/ml) also significantly suppressed colon cancer cells migration in the zebrafish embryos. Furthermore, oral administration of PVW (1.6 g/kg) significantly inhibited tumor growth by decreasing the expressions of tumor activation marker Ki-67 and CD 31 in tumor tissues of HCT116 tumor-bearing mice. PVW could also significantly inhibit lung metastasis in colon 26-luc tumor-bearing mice by modulating their tumor microenvironment, including immune cells populations (T cells and MDSCs), levels of cytokines (IL-2, IL-12, and IFN-γ), as well as increasing the relative abundance of gut microbiota. CONCLUSION: This study revealed for the first time the anti-tumor and anti-metastatic effects of PVW through regulation of TGF-ß-smad2/3-E-cadherin, and FAK-cofilin pathways in colon cancer. These findings provide scientific evidence to support the clinical use of P. villosa in patients with colon cancer.