Rhubarb inhibits hepatocellular carcinoma cell metastasis via GSK-3-β activation to enhance protein degradation and attenuate nuclear translocation of β-catenin

The aim of our study was to investigate the mechanisms by which rhubarb regulates beta-catenin as well as metastasis of hepatocellular carcinomas. Our results revealed that rhubarb extract inhibited HA22T cell migration ability in wound healing, migration and invasion assays in a dose-dependent manner. Rhubarb also reduced beta-catenin protein level, downregulated its downstream proteins, cyclin D, Tbx3 and c-Myc, and attenuated the expression of MMP9 and contactin-1 metastatic factors. Additionally, rhubarb inhibited beta-catenin nuclear accumulation and induced its degradation via proteasome-mediated pathway. Furthermore, we found that rhubarb suppressed the p-ser(9) GSK-3-beta protein level to inactivate Wnt signalling and reduce beta-catenin protein level. Taken together; we found that rhubarb blocked the metastatic process of HA22T hepatocellular carcinoma cells mediated through GSK-3-beta activation, and enhancement of protein degradation as well as reduction of the nuclear accumulation of beta-catenin. (C) 2012 Elsevier Ltd. All rights reserved.