Abstract
BackgroundGlioblastoma (GBM) is a tumor of the central nervous system carries an extremely poor prognosis. Unfortunately, it also is the most frequently encountered tumor in this region. These tumors arise from glioblastoma stem cells (GSCs), which are glioma cells that are known to possess high degrees of stemness. GBM invades through the process of EMT, which features loss of cell differentiation and polarity. Survivin is a type of apoptotic inhibitor that has been characterized in several malignancies such as glioma. Normal tissues rarely express survivin. On the other hand, 3-benzyl-5-((2-nitrophenoxy) methyl) dihydrofuran-2(3H)-one (3BDO) represents an autophagy inhibitor and activates the mTOR pathway. It has been reported that 3BDO shows anti-cancer activities in lung carcinoma. However, the effects of 3BDO on GBM reminds unknown. Therefore, the purpose of this study was to explore the role and molecular mechanisms that 3BDO mediates in GBM.MethodCCK-8 experiments and clone formation assay were performed to detect the cell proliferation. Transwell assay was conducted to examined cell migration and invasion. Western blotting and immunofluorescence staining was used to analyze protein expression levels. Xenograft mouse model was used to evaluate the effect of 3BDO in vivo.ResultsWe found that 3BDO inhibited U87 and U251 cell proliferation in a dose-dependent manner. Additonally, 3BDO decreased the sphere formation and stemness markers (sox2, nestin and CD133) in GSCs. 3BDO also inhibited migration, invasion and suppressed EMT markers (N-cadherin, vimentin and snail) in GBM cells. Moreover, we found that 3BDO downregulated survivin expression of survivin both in GBM cells (U87, U251) and GSCs. Furthermore, overexpression of survivin reduced the therapeutic effects of 3BDO on GBM cell EMT, invasion, migration and proliferation, as well as decreased stemness in GSCs. Finally, we demonstrated that 3BDO inhibited tumor growth in a tumor xenograft mouse model constructed using U87 cells. Similar to the in vitro findings, 3BDO diminished suvivin expression, stemness and levels of EMT makers in vivo.Conclusionsour results demonstrated that 3BDO repressed GBM via downregulating survivin-mediated stemness and EMT both in vitro and in vivo.