[The role of FOXO3a-Bim signaling in triptolide induced bladder cancer T24 cells apoptosis].

Objective: To investigate the role of FOXO3a-Bim signaling in triptolide induced bladder cancer T24 cells apoptosis. Methods: T24 cells were used and divided into control group, triptolide group(50 nmol/L), MK2206 group(50 nmol/L triptolide+ 5 μmol/L MK2206), FOXO3a-siRNA group(50 nmol/L triptolide+ 100 nmol/L FOXO3a-siRNA), Bim-siRNA group (50 nmol/L triptolide+ 100 nmol/L Bim-siRNA). MTT assay was used to analyze the cells growth inhibition.Annexin V/PI staining was implemented to detect cell apoptosis rate, the expression of p-Akt, Akt, p-FOXO3a, FOXO3a, Bim, Bax.Cleaved-caspase 3 was analyzed by Western blot. Results: After treatment with triptolide 25, 50, 100, 250 nmol/L, the cell growth inhibition rates at 24 hours(17%±9%, 24%±5%, 43%±8%, 61%±8%), 48 hours (20%±7%, 34%±6%, 56%±7%, 74%±5%) and 72 hours(32%±8%, 41%±7%, 69%±7%, 84%±3%) were significantly higher than control group respectively.The IC(50) at 24, 48, 72 hours were (113±10), (91±8), (68±5) nmol/L; the cell apoptosis rates at 24 hours (10%±4%, 15%±5%, 29%±8%, 46%±8%), 48 hours (16%±5%, 24%±6%, 40%±7%, 55%±9%) and 72 hours (27%±4%, 38%±5%, 50%±9%, 65%±8%) were significantly increased ( P <0.05). Western blot showed that triptolide reduced the expression of p-Akt, p-FOXO3a and increased the expression of Bim, Bax, cleaved-caspase 3.The cell inhibition rate in Triptolide group (30%±8%) was significantly higher than that in the control group ( P <0.05) and the rates in MK2206 group (54% ±6%), FOXO3a-siRNA group (18%±7%) and Bim-siRNA group (11%±6%) were also higher than the control group.Compared with the triptolide group, the inhibition rate in MK2206 group was significantly increased, but decreased in FOXO3a-siRNA group and Bim-siRNA group( P <0.05). Conclusion: Triptolide induces T24 cells apoptosis through FOXO3a-Bim signaling pathway.