Effects of Glycogen Synthase Kinase-3β (GSK3β) Inhibition in Glioblastoma Using Novel Compounds

Abstract

Abstract AIMS GSK3β is a constitutively conserved serine/threonine kinase involved in a number of biological processes including cell cycle progression, apoptosis, cellular metabolism, proliferation and differentiation. High expression levels in the brain make this kinase a potential target for treatment of neurological disorders. The aim was to investigate the anti-proliferative and cytotoxic effects of four novel highly selective, type-II GSK3β inhibitors identified by in silico analysis of naturally occurring compounds. METHOD We demonstrate the effects on the cell viability of immortalised cell lines (grade 4 glioblastoma U87MG, foetal astrocytes SVGp12) and short-term glioblastoma patient derived cultures (PD301 and PD304). The compounds were incubated with cells for 24, 48 and 72h and then assayed for cell viability using MTS. The concentration of inhibitors was determined from previous IC50 experiments on purified GSK3β enzyme. The changes in activity status of GSK3β pre- and post-treatment were also determined using immunohistochemistry or Western Blotting. RESULTS Two of the compounds caused significant decrease in cell viability at 24h and 3uM as shown by decrease in viability of 20.5% relative to control. This decrease was larger in the glioma cell lines relative to the glial non-cancerous control (13%). Western blot analysis revealed that activating phosphorylation sites were detectable. More work is needed to determine if this is the mechanism by which reduction in cell viability occurs. CONCLUSION Two of the selected novel compounds have demonstrated ability to decrease glioblastoma cell viability. Future studies will include analysis of the compounds in relation to the BBB-glioma in vitro model.