The Research Of Possible Mechanism Of Benzidine-induced Bladder Cancer And Prevention Interventions Of The High Risk Population In Community

Background and purpose: Bladder cancer is the common malignancy of the urinary tract, which occupy the first bit of urinary reproductive tumour in our country. Every year, high cost of bladder cancer diagnosis, treatment the recurrence of monitoring and treatment of related complications was used, which caused to significant economic burden to patients in community. Due to the invasive and expensive of cystoscopy, and also the low sensitivity of cytology, the discovery of new biomarkers for the early diagnosis, detection and prognosis of patients plays an important role for the general population and the population of need for monitoring and easy recurrence of bladder cancer. In recent years, although the epidemiological findings have identified benzidine exposed close relation with bladder cancer, but its related carcinogenic mechanism is still not very clear. Studies have shown that abnormal cell proliferation is necessary in the development of tumor formation process, this shows that in the human long exposure and touch some environmental pollutants resulting in abnormal cell proliferation of related organization induced tumorigenesis and may promote the development of tumor. This study to investigate benzidine-mediated intracellular PI3K/Akt signaling cascades leading to cell proliferation in human uroepithelial cells(SV-HUC-1) and to further explicit the possible mechanism of benzidine induced bladder cancer, and on the basis of looking for a new noninvasive, high sensitivity, specificity and simple tumor markers for bladder cancer diagnosis and follow-up and provide scientific basis for precancerous intervention treatment.Methods: SV-HUC-1 cells were treated with different concentration of benzidine(0, 0.001, 0.005, 0.01, 0.05, 0.1umol/L) for 96 h. Then MTT method was used to detect the change of the living rate after cells were exposed to different concentrations of benzidine, Flow cytometry method was used to detect the change of the cell cycle, Western blot was used to examine the expression of Akt?p-Akt?Cyclin D1?PCNA?P21 and GAPDH proteins. Reverse transcription-polymerase chain reaction(RT-PCR) was used to detect the expression of Cyclin D1?P21 m RNA. Finally,after PI3K/Akt signaling pathway was cutted down when using blockers(LY294002), then use the MTT method to analyze cell proliferation and use Western blot to detect the expression of p-Akt,Cyclin D1, and P21 proteins.Results: After SV-HUC-1 cells were stimulated with lower concentration of benzidine, MTT absorbance value was significantly higher than the control group. Flow cytometry of cell cycle percentage change in the experimental group and control group suggests that Dip G2 + S increased from 33.33% to 52.41%; Dip G1 reduced to 47.59% from 66.67%. Benzidine induced the cell cycle protein cyclin D1?PCNA and signaling pathways p-Akt expression and reduced cell cycle protein P21. After using blocker(LY294002) blocked PI3K/Akt signaling pathway, the MTT absorbance values of the originally cell proliferation of benzidine treatment group was drop, and the expression levels of p-Akt, Cyclin D1 were decreased, while the expression level of P21 was increased.Conclusion: Benzidine induced cell proliferation through activating PI3K/Akt signaling pathways and the expression of related proteins of cell cycle(Cyclin D1?PCNA?P21) were abnormal. We think that the abnormal expression of the related proteins of cell cycle(Cyclin D1?PCNA?P21) may be as new markers of detecting bladder tumor. Therefore, for the high risk pipulation of possible exposure to benzidine in community, we can combine detection of tumor markers of early classical urine cells and Cyclin D1?PCNA?P21 to screen bladder tumor patients and to act a basis for follow-up, and provide scientific basis for precancerous intervention treatment.