Omaveloxolone Suppresses Cell Growth and Causes Cell Cycle Arrest by Downregulating CDC20 Expression in Glioblastoma Cells Both In Vitro and In Vivo

Omaveloxolone is a synthetic oleanane triterpene with considerable antitumor activity. It induces human glioblastoma (GBM) cell death in vitro and in vivo, but the underlying mechanism remains to be determined. In this study, GBM cell lines (GBM8401 and U-87 MG cells) were exposed to different concentrations of omaveloxolone (0, 600, 800 and 1000 nM). A cell viability assay was conducted using the PrestoBlue Cell Viability Reagent. Three-dimensional microscopy revealed changes in cell morphology. Cell cycle, apoptosis and mitochondrial membrane potential were tested using flow cytometry. The expression levels of cell cycle-related proteins and genes were determined through Western blotting and next-generation sequencing, respectively. The results indicated that omaveloxolone had significant selective cytotoxicity against human GBM cells and suppressed the migration and invasion of these cancer cells. It also caused cell cycle arrest through the downregulation of cell cycle-related genes, including cell division cycle 20 homologue (CDC20), as revealed by next-generation sequencing. In a xenograft tumour model, omaveloxolone decreased tumour volume and CDC20 expression. Taken together, these findings suggest that omaveloxolone is a potential drug candidate for GBM treatment by promoting GBM cell death through the downregulation of CDC20 expression.