Effect of mifepristone on chemosensitivity of human cervical squamous carcinomacells to cisplatin

Objective To investigate the effect and its mechanism of mifepristone on chemosensitivity of human cervical squamous carcinoma cells to cisplatin and to give experimental basis for cervical squamous carcinoma with mifepristone.Methods Human cervical squamous carcinoma cell line Caski cells were cultured in vitro.Caski cells were treated with various concentration of mifepristone or cisplatin or both.Cell proliferation was evaluated by MTT assay.The apotosis of Caski cells were determined by PI staining flow cytometry and cell cycle was analyzed using flow cytometry.The expression and their activity change of HPV16-E6,p53,Bcl-2,Bax protein in Caski cells were investigated by FITC staining flow cytometry.Results(1) MTT assay indicated that mifepristone at concentrations 1.25,2.5 mg/L was not of cytotoxicity to Caski cells(IR5%),but it significantly increased the cytotoxicity of cisplatin to Caski cells(q(1.15)).(2) PI staining flow cytometry data showed the apoptosis of Caski cells could not be induced by mifepristone at concentrateions 1.25,2.5 mg/L,whereas,mifepristone(1.25 mg/L) significantly promoted cisplatin(1.0,2.0,4.0 mg/L) to induce Caski cells apoptosis.(3) FITC staining flow cytometry indicated the expression of HPV16-E6,Bcl-2 protein decreased and the expression of p53 and Bax protein increased in Caski cells treated with mifepristone in a concentrateion dependent manner(P0.05).Conclusion Mifepristone(1.25,2.5 mg/L) enhances the effect of growth inhibition and apoptosis induction of cisplatin on Caski cells.The effect of chemosensitization to cisplatin of mifepristone on Caski cells is associated with downregulating expression of HPV16-E6,Bcl-2 protein and upregulating expression of p53 and Bax protein.