Anti-metastatic effects of Rheum Palmatum L. extract in human MDA-MB-231 breast cancer cells

• RPE inhibited migration and invasion of MDA-MB-231 cells.
• RPE attenuated the expression levels of MMP-2/-9 and uPA secretions.
• RPE affected NF-κB by degrading IkBα.
• RPE suppressed the expression levels of P38, ERK and AKT.

Rheum palmatum L. (RP) has been widely used in traditional medicine for the treatment of various diseases in Asian countries. The molecular mechanism of its anti-metastasis effect remains elusive. The present study assessed the effect of RP ethanol extract (RPE) on the highly metastatic human MDA-MB-231 breast cancer cells in vitro. At a non-toxic concentration, RPE inhibited migration, motility and invasion in a concentration-dependent manner. To investigate the mechanisms involved, real-time PCR and Western blot analyses were performed. Results showed that RPE down-regulated the levels of extracellular matrix degradation-associated proteins, including MMP-2/-9, uPA and uPAR, and up-regulated PAI-1. In addition, RPE affected NF-κB by degrading IkBα, and affected the mitogen-activated protein kinase signal transduction pathway by depressing the activation of p38, ERK and Akt. These results suggest that RPE has potential anti-metastatic activity and warrants further investigation.