Abstract

We studied Notch signaling and its potential target, Twist1, in five matched primary and recurrent glioblastoma patient-derived stem cells. Among these genes, Twist1 was significantly upregulated in primary and recurrent cells. To probe the underlying mechanism, quantitative PCR and Western blot analysis were used to detect Notch intracellular domain (NICD) and Twist1 expression in cells treated with NICD lentivirus, Notch antagonist, or Twist1-shRNA. Cell proliferation, neurosphere formation, cell migration, and in vivo experiments were performed to evaluate the biological functions of Notch/Twist1. Luciferase reporter and chromatin immunoprecipitation assays were performed to confirm the possible binding site of Twist 1 for NICD. The results showed glioblastoma-derived stem cells maintained stemness and multipotency abilities. Activation of Notch signaling induced upregulation of Twist1, thus enhancing cell proliferation and invasion. Silencing of Twist1 markedly hindered the acceleration effect of NICD on glioma stem cells, and therefore suppressed tumor growth rate in orthotopic glioma-bearing mice. The underlying mechanism showed that NICD directly bound to RBPJK in Twist1 promoter, which contributed to regulation of cell biological behaviors. Taken together, these results suggest that Notch signaling is involved in progression of gliomas by directly targeting Twist1.