Therole Of P53 Protein In Apoptosis Of Transitional Epithelial Carcinoma Of Bladder Induced By Mitomycin C

Objective:We investigated the role of P53 protein in mitomycin C-induced apoptosis of bladder transitional cell carcinoma and clarified its molecular mechanism,in order to lay a foundation for reducing the recurrence rate and increasing the survival rate of patients with bladder transitional cell carcinoma by precise chemical therapy.Methods:The control group,10 g/mL mitomycin C group and P53 inhibitor group were established with T24 human bladder transitional cell carcinoma cell lines.In the P53 inhibitor group,cells were pretreated with 5 micromol/L p53 inhibitor,Pifithrin-alpha(PFTalpha)HBr,for 60 minutes and then 10 g/mL mitomycin C was added.Annexin V-FITC staining,Hoechst staining and Western Blotting technique were used to detect apoptotic cells.After cell lysis,the expression or content of Caspase 8,BCL-2 and Bax proteins in bladder transitional cell carcinoma cells were detected by ELISA or Western Blotting assay.Results:Annexin V-FITC-PI staining showed that the apoptotic rate of T24 cells in mitomycin C group and P53 inhibitor group was significantly higher than that in control group(P < 0.01);compared with mitomycin C group,the apoptotic rate of T24 cells in P53 inhibitor group was significantly lower(P < 0.01).Hoechst staining showed that most of the nuclei in mitomycin C group were strongly fluorescent,with fragmented nuclei and occasionally normal nuclei.In p53 inhibitor group,moderate intensity fluorescent staining was observed without nuclear fragmentation.The intensity of nuclear fluorescence staining showed that compared with the normal control group,the intensity of nuclear fluorescence in mitomycin C group and p53 inhibitor group increased significantly(P < 0.01).However,the nuclear fluorescence intensity of p53 inhibitor group was significantly lower than that of mitomycin C group(P < 0.01).Western Blotting results showed that in mitomycin C group and p53 inhibitor group,the expression of Caspase 8 and Bax protein was significantly higher and the expression of Bcl-2 protein was significantly lower than that in control group(P < 0.01).While in p53 inhibitor group,the expression of Caspase 8 and Bax protein was significantly lower and the expression of Bcl-2 protein was significantly increased than that in mitomycin C group(P < 0.01).ELISA results showed that compared with control group and p53 inhibitor group,Bcl-2 protein content was significantly decreased and Bax protein content was significantly increased in mitomycin C group(P < 0.01).Conclusion:(1)10 g/mL mitomycin C can induce apoptosis of bladder transitional cell carcinoma cell line T24;10 g/mL mitomycin C can induce increased expression of Caspase 8 and Bax and decreased expression of Bcl-2 in T24 cells;(2)P53 signaling pathway promotes mitomycin C-induced apoptosis of T24 bladder transitional cell carcinoma cells.