FLT Synergizes With TMZ Toinduce Chop- Dependent Ersrelated Apoptosis Pathway In Glioma

Glioma is generated by canceration of the brain cells and spinal cord glial cells,the most common intracranial tumor,Accounts for about 50% of brain tumors,Due to its growth characteristics in invasive,It’s difficult to radical resection of the tumor in surgically at clinically,so chemotherapy after surgery to become an important way to prolong survival time.Because of temozolomide(TMZ)can quickly through the blood brain barrier,and bioavailability of close to 100%,temozolomide(TMZ)has became the most effective chemotherapy agents for glioma,chemotherapy resistance limited its clinical use.Fluoxetine(FLT),which is widely used in cancer related depression,Studies have shown that fluoxetine can inhibit the action of the depression occurs,,enhanced patients’ immunity,anti-inflammatory,exhibited potent anticancer properties in different cancer cell types.Antidepressant treatment has become an important adjuvant therapy of cancer.PurposeThe aim of this study is to 1)evaluate the antitumor mechanism of FLT,and 2)further evaluate the combination of FLT and temozolomide(TMZ)in giloma cells.3)Apply the theoretical basis of cell and molecular biology for FLT become adjuvant therapy of cancer.MethodsThe glioma cell lines were exposed to FLT and/or TMZ.The cell viability,apoptosis were examined by CCK-8 assay,flow cytometry and caspase activity assay,respectively.The expression of ER-stress apoptosis related proteins was measured using real-time PCR and western blotting.Synergism between 2 drugs was evaluated by the combination index(CI)through CompuSyn software.ResultsFLT significantly and dose-dependently inhibited various glioma cell lines proliferation,and rat glioma C6 cells had a highly sensitive response to the addition of FLT.FLT treatment increased early apoptosis rate,induced typical apoptotic morphology in C6 cells and activated the Caspase 3 with no change in the mitochondrial membrane potential.Further study showed FLT activated ERS marker-CHOP,This induction was associated with the activation of the PERK-eIF2α-ATF4 and ATF6 cascade.Concomitantly,GADD34-the downstream moleculus of CHOP was also increased.Combined FLT and TMZ treatment showed a synergistic cytotoxic effect in C6 glioma cell(CI<1).Knockdown of CHOP expression abolished the synergistic effect of FLT with TMZ in C6 cells,which suggested that FLT might sensitize glioma cells to TMZ through activating CHOPdependently apoptosis pathway.ConclusionsThese results revealed that FLT induced apoptosis through the activation of the CHOP-dependent ER stress pathway in C6 glioma cell.FLT might sensitize glioma cells to TMZ through activating CHOP-dependently apoptosis pathway The current study provides a primary basis for using the combination of these drugs in patients with advanced glioma cancer.