Cucurbitacin E inhibits the proliferation of glioblastoma cells via FAK/AKT/GSK3β pathway

Glioblastoma (GBM) is the most common primary intracranial tumor in the brain with high growth rate and high mortality rate. Cucurbitacin E (CUE), a tetracyclic triterpene compound derived from species of the genus Cucurbita, has been demonstrated to display significant antitumor effects on various malignancies. In the present study, the effects of CUE on GBM and its underlying molecular mechanisms were explored. The data revealed that CUE inhibited the proliferation of the GBM cell lines U87-MG and U251-MG in a dose- and time-dependent manner. Mechanistically, CUE reduced the phosphorylation of focal adhesion kinase (FAK), protein kinase B (AKT), and glycogen synthase kinase-3β (GSK3β) at both basal and epidermal growth factor (EGF)-induced levels. Moreover, CUE inhibited the proliferation of U87-MG and U251-MG cells by blocking EGF-induced phosphorylation of the FAK, AKT and GSK3β. Subsequently, CUE reduced the expression of cyclinD1 and cyclinB1. Collectively, these results indicated that CUE inhibited the proliferation of U87-MG and U251-MG cells by suppressing the FAK/AKT/GSK3β signaling pathway, which also suggested that CUE has potential application in treating GBM.