Effect of AZD6918 on BDNF/TrkB-mediated rescues of cell death in vitro. TB3 cells were pretreated with AZD6918(2.5 μM) for 2 hours followed by BDNF (100 ng/ml) treatment for 1 hour, and then treated with etoposide (A:1 μg/ml; B and C: 3 μg/ml) for 24 hours. To inhibit the expression of TrkB, TB3 cells were cultured in media with tetracycline (TET, 1 μg/ml) for at 3 d before experiment. MTS assay was used to assess cell survival. ** P < 0.01, etopside-treated cells via BDNF + Etoposide treated cells; ## P < 0.01, BDNF + Etoposide treated cells via BDNF + Etoposide + AZD6918 treated cells. ns: no statistical difference. (D) TB3 cells were pretreated with AZD6918 (2.5 μM) for 2 hours followed by BDNF(100 ng/ml) treatment for 1 hour, and then harvested for the evaluation of P-TrkB, P-Akt, P-mTOR, P-GSK-3 and GAPDH by Western Blotting. E: TB3 cells were transfected with activated Akt or empty vector plasmids by lipofectamine 2000 and treated with AZD6918 at 24 h after transfection. MTS assay was used to assess cell survival. ** P < 0.01, activated Akt-transfected cells via empty vector transfected cells.