Activation of beta-catenin signalling by GSK-3 inhibition increases p-glycoprotein expression in brain endothelial cells

作者：Lim Joseph C; Kania Katarzyna D; Wijesuriya Hasini; Chawla Sangeeta; Sethi Jaswinder K; Pulaski Lukasz; Romero Ignacio A; Couraud Pierre O; Weksler Babette B; Hladky Stephen B; Barrand Margery A^*

来源：Journal of Neurochemistry, 2008, 106(4): 1855-1865.

DOI：10.1111/j.1471-4159.2008.05537.x

• beta-catenin
• breast cancer resistant protein
• glycogen synthase kinase-3
• multidrug resistance protein 4
• p-glycoprotein
• brain endothelial cells

This study investigates involvement of beta-catenin signalling in regulation of p-glycoprotein (p-gp) expression in endothelial cells derived from brain vasculature. Pharmacological interventions that enhance or that block beta-catenin signalling were applied to primary rat brain endothelial cells and to immortalized human brain endothelial cells, hCMEC/D3, nuclear translocation of beta-catenin being determined by immunocytochemistry and by western blot analysis to confirm effectiveness of the manipulations. Using the specific glycogen synthase kinase-3 (GSK-3) inhibitor 6-bromoindirubin-3'-oxime enhanced beta-catenin and increased p-gp expression including activating the MDR1 promoter. These increases were accompanied by increases in p-gp-mediated efflux capability as observed from alterations in intracellular fluorescent calcein accumulation detected by flow cytometry. Similar increases in p-gp expression were noted with other GSK-3 inhibitors, i.e. 1-azakenpaullone or LiCl. Application of Wnt agonist [2-amino-4-(3,4-(methylenedioxy) benzylamino)-6-(3-methoxyphenyl)pyrimidine] also enhanced beta-catenin and increased transcript and protein levels of p-gp. By contrast, down-regulating the pathway using Dickkopf-1 or quercetin decreased p-gp expression. Similar changes were observed with multidrug resistance protein 4 and breast cancer resistance protein, both known to be present at the blood-brain barrier. These results suggest that regulation of p-gp and other multidrug efflux transporters in brain vasculature can be influenced by beta-catenin signalling.

• 出版日期2008-8