Glycogen synthase kinase-3Β regulates astrocytic differentiation of U87-MG human glioblastoma cells

Abstract

Aim: To evaluate the role of glycogen synthase kinase-3Β (GSK-3Β) in the induced differentiation of human glioblastoma cells. Methods: Cell proliferation was determined by bromodeoxyuridine (BrdU) incorporation assay. The protein level of p-GSK-3Β, GSK-3Β, glial fibrillary acidic protein (GFAP) and proliferating cell nuclear antigen (PCNA) were determined using Western blots. The overexpression of mutant GSK-3Β was analyzed by immunocytochemistry. Results: The biotoxin cholera toxin is capable of inducing differentiation of U87-MG human glioblastoma cells, which is characterized by morphological changes to astrocytic phenotype, increase in differentiation marker protein GFAP and decrease in proliferation. GSK-3Β activation is induced during this differentiation. Small interfering RNA against GSK-3Β suppresses the induced-differentiation in U87-MG cells. Conversely, overexpression of a constitutively active form of human GSK-3Β (pcDNA3-GSK-3Β-S9A) mutant leads to differentiation of U87-MG cells. Conclusion: Our findings suggest that GSK-3Β plays an important role in astrocytic differentiation of human glioblastoma cells and may be a novel therapeutic target in the malignant tumor. © 2010 CPS and SIMM. All rights reserved.