Investigation of the anti-migratory properties of GSK-3 inhibitors in glioblastoma

Glioblastoma is the most malignant form of brain cancer. Due to its aggressive nature, extensive research has been performed, but little progress has been made in identifying effective treatment options. Glycogen synthase kinase-3 (GSK-3) is a ubiquitous, multifaceted protein kinase. Previous studies have shown that small molecule inhibitors of GSK-3 block the migration of glioblastoma cells and may prevent spread of tumor in the brain. However, these studies were performed using non-selective GSK-3 inhibitors (LiCl and an indirubin derivative, BIO), thus it was unclear whether GSK-3 was the most important target. In this study, we used recently generated highly selective GSK-3 inhibitors (CHIR99021, AZD1080, and AZD2858, as well as BIO) to investigate these questions. These were applied to four glioblastoma cell lines: G30, G9, U251, and U1242, in three migration assays: transwell, spheroid, and wound healing (scratch) assay to further assess the suitability of GSK-3 as a target in glioblastoma. We also utilized the ATP Luciferase reporter assay for cell viability to assess the influence of our panel of drugs on cell migration versus viability. In addition, the TOPFlash Luciferase reporter assay was performed as an indicator of the level of GSK-3 inhibition. The TOPFlash assay showed that all GSK-3 inhibitors were able to increase luciferase levels. This indicates that GSK-3 was inhibited in our cells after drug treatment. The transwell assays showed us that the GSK-3 inhibitors were able to block