KDR and central nervous system cancer: To further explore the enhanced expression of these factors, transdifferentiation-induced C6 glioma cells were treated with DAPT (γ-secretase inhibitor that effectively inhibits Notch signaling) [21], sunitinib (VEGFR2 tyrosine kinase inhibitor currently in clinical trial) [23], normoxia or vehicle control for 24 h, respectively.