Influence Of XPF Small Interference RNA On Carboplatin Sensitivity Of Uterine Endometrial Cancer Ishikawa Cells

Endometrial carcinoma is one of the most common tumors of femalereproductive system and in third place in gynecological malignant tumor.Treatment of uterine endometrial carcinoma is mainly operation, combiningwith radiotherapy, chemotherapy and other means. In the process ofchemotherapy for patients with endometrial cancer, a blazing case often occured,the different endometrial cancer patients with the same TNM stage, the samepathological type, the same degree of cell differentiation, using the samechemotherapy, have the quite different prognosis.In this research, the small interfering RNAs (siRNA) targeting XerodermaPigmentosum group F (XPF) gene were designed and synthesized. The siRNAswere transfected mediated by lipofectamine into human endometrial carcinomacell line Ishikawa, to reduce endometrial cancer cell XPF gene expression level,reduce the formation of ERCC1-XPF complex, weaken repair capability ofDNA in endometrial carcinoma cells, supress uterine endometrial carcinomacell proliferation, increase sensitivity of endometrial carcinoma cells tocarboplatin-based chemotherapies, and reduce the resistance of endometrialcarcinoma cells to carboplatin.Objective: This study is to explore the influence of XPF small interferenceRAN on carboplatin sensitivity of uterine endometrial cancer Ishikawa cells,and to provide experimental basis for reversing new targets and methods of drugresistance in endometrial carcinoma. Methods：Small interference RNAs targeting XPF gene (XPF-siRNA1andXPF-siRNA2) were synthesized by chemical method; XPF-siRNAs weretransfected into Ishikawa cells by lipofectamine; XPF mRNA levels of Ishikawacells were detected by RT-PCR; the expression of XPF protein was detected byWestern Blot; the change of Ishikawa cells sensitive to carboplatin was detectedby MTT experiments. The change of inhibitant concentration50(IC50) ofIshikawa cells to carboplatin was calculated after RNA interference.Results: After the transfection of XPF-siRNA into Ishikawa cells, thebright green fluorescence could be seen by inverted fluorescence microscope.XPF mRNA levels present lower expression in XPF-siRNA1and XPF-siRNA2transfection group than that in Neg-siRNA control group. And XPF proteinlevels also appearced lower expression in XPF-siRNA1and XPF-siRNA2transfection group than that in Neg-siRNA control group (p<0.05). MTTexperiments results showed that after the transfection of XPF-siRNA, theproliferation inhibition rate of endometrial carcinoma Ishikawa cells haveobvious change in carboplatin stimulation. XPF-siRNA1transfection group was88.1%, XPF-siRNA2transfection group was81.5%, while Neg-siRNAtransfection group was49.7%. The value of IC50in Neg-siRNA transfectiongroup was180±7.2μmol/L, while XPF-siRNA1transfection group was92.8±6.4μmol/L, XPF-siRNA2transfection group was101.5±4.9μmol/L.Conclusion: XPF-siRNA1and XPF-siRNA2can decrease effectively themRNA level of XPF and the expression of XPF protein in endometrial carcinoma Ishikawa cells; After XPF-siRNA transfection, the proliferationinhibition rate of endometrial carcinoma Ishikawa cells increased undercarboplatin influence in equal concentration and IC50of Ishikawa cells tocarboplatin decreased. The results illustrated that the sensitivity of Ishikawacells to carboplatin enhanced after XPF-siRNA transfection. The decreasingexpression of XPF protein decrease the formation of ERCC1-XPF complex,weaken repair capacity of DNA in endometrial carcinoma cells, inhibiteproliferation of uterine endometrial carcinoma cells, increase sensitivity ofendometrial carcinoma cells to carboplatin-based chemotherapies, reduce theresistance of endometrial carcinoma cells to carboplatin.