Characterization of polysaccharide from Scutellaria barbata and its antagonistic effect on the migration and invasion of HT-29 colorectal cancer cells induced by TGF-β1

In this study, we purified a water-soluble polysaccharide, SBPW3, from the whole plant of Scutellaria barbata D. Don through ethanol precipitation, deproteinization, lyophilization, dialysis and separation using a DEAE cellulose column and a Superdex 200 gel filtration chromatography column. SBPW3 is a homogeneous polysaccharide with a molecular weight of 10.2 kDa and is composed of rhamnose (2.51%), arabinose (25.68%), xylose (10.94%), mannose (12.56%), glucose (20.59%) and galactose (27.72%). FT-IR spectrum analysis of the polysaccharide showed that SBPW3 contained a pyranose ring. The effects of SBPW3 on TGF-beta 1-induced epithelial-mesenchymal transition (EMT) were tested in colon cancer cells. These results suggested that SBPW3 significantly suppressed TGF-beta 1-induced migration and invasion. Additionally, SBPW3 reduced EMT by increasing the expression of epithelial markers and by decreasing the expression of mesenchymal markers by blocking the Smad2/3 signalling pathway in colon cancer cells. Furthermore, to explore the anti-metastatic effect of SBPW3, we established a mouse model of colon cancer metastasis and found that SBPW3 significantly inhibited the metastatic dissemination of the primary tumour to the liver. These findings provide us with a potential chemotherapeutic strategy for the treatment of human colorectal cancer. (C) 2019 Published by Elsevier B.V.