Optimization of polysaccharides extracted from Verbena officinalis L and their inhibitory effects on invasion and metastasis of colorectal cancer cells

Abstract

Purpose: To investigate polysaccharides (PEV) extracted from the aerial part of Verbena officinalis L. and their inhibitory effects on the invasion and metastasis of colorectal cancer (CRC) cells.Methods: PEV was extracted by water and the optimization of extraction conditions was performed using a Box-Benhnken design (BBD). The cell viability was evaluated by 4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide (MTT) assay. The effects of PEV on cell adhesion and invasion were evaluated by Transwell invasion, wound healing migration and adhesion assays in vitro. The effects of PEV on the expressions of matrix metalloproteinase-9 (MMP-9), mesenchymal-epithelial transition factor (C-met), E-cadherin (E-CAD), cyclooxygenase-2 (COX-2) and E-prostanoid 2 receptor (EP2) were investigated by western blot.Results: The BBD model was established successfully for the optimization of PEV extraction (p <0.0001). The results indicate that PEV (50, 100 and 200 μg/mL) had significant inhibitory effects on cell invasion and migration of SW480 cells (p < 0.05). PEV also significantly decreased cell adhesion of SW480 cells. By treating with PEV, the expressions of C-met, MMP-9, COX-2 and EP2 were decreased, whereas the expression of E-CAD increased in SW480 cells.Conclusion: RSM is effective for optimizing the extraction conditions of PEV. More importantly, PEV significantly inhibits the invasion and metastasis of SW480 cells by regulating the expression of MMP-9, C-met, E-CAD, COX-2 and EP2. Thus, PEV has the potential to be developed into therapeutic drugs for CRC in the future.Keywords: Polysaccharides, Colorectal cancer, Verbena officinalis, SW480 cell lines, Cell invasion, Metastasis