Effect Of Reduced Expression Of PARP-1 By RNA Interference On Cisplatin Resistance And Proliferation In The Ovarian Cancer Cell Line

Backgroud:Epithelial ovarian carcinoma has its high mortality rate, complex biological characteristics, and low 5 year survival rate due to its low rate of early detection, easy to relapse, and the difficulty of treatment in advanced stage, which led ovarian cancers to the most threaten of female genital malignant diseases. The major reason for the mortality of this cancer is the high metastatic ability and the resistance to chemotherapy. Although great improvement has been made in standard therapy for ovarian cancer, the mechanism of the drug-resistant and relapses is not clear yet. Identifying the molecular mechanism of drug resistance of ovarian cancer, and finding the effective therapeutic targets has become a hot field for exploring the target for new drugs among domestic and foreign scholars of gynecologic oncologists.Objective:1. To observe the differential expression of PARP-1 in chemosensitive ovarian cancer cell OV2008 and its resistant variants C13*.2. PARP-1 siRNA mediated by lentiviral vector was constructed and transfected into C13* cell.3. Observe the effect of transfer exogenous PARP-1 gene on epithelial ovarian carcinoma drug-resistance cell.4. Discusses the relationship of PARP-1 and the drug resistance of ovarian carcinoma.Method:1.Check IC50 of the drug-resistant epithelial ovarian carcinoma cell C13* to OV2008 through MTT, and calculate resistant index·2. Expression of PARP-1 mRNA and protein in C13* and OV2008 cells were detected by RFQ-PCR (real-time fluorogenic quantitative PCR, RFQ-PCR) and Western blotting, respectively.3. RFQ-PCR and Western blotting were used to validate whether the PARP-1 was silenced.4. The influence of siRNA on cellular sensitivity to cisplatin and cellular proliferation activity were detected by MTT assays.Results:1.The resistant index of C13* is 3.96, which could be used in the test.2. The PARP-1 mRNA and protein levels in C13* cells were (2.12±0.97) and (1.89±0.23) folds of those in OV2008 cells. The difference was significant (P<0.05). After OV2008 and C13* cells treated with 10μmol/L CDDP for 24 h, PARP-1 protein levels decreased in chemosensitive, but not resistant, ovarian cancer cells.3. Short siRNA targeting PARP-1 down-regulated the PARP-1 mRNA and protein levels (P<0.05). The mRNA and protein expressions of PARP-1 were decreased by (71.23±5.41)% and (73.84±3.78)%, respectively (P<0.05).4. The IC50 of cisplatin was decreased by (63.49±10.06)% (P<0.05), and the proliferation activity of C13* cells was inhibited. The difference was significant (P<0.05).Conclusion:PARP-1 gene expression is higher in epithelial ovarian carcinoma drug-resistance cell. Over expression of PARP-1 was definitely related to the decline of cellular sensitivity to cisplatin. Deregulating the expression of PARP-1 domains in epithelial ovarian carcinoma cell lines in vitro could weaken the cellular tolerance to cisplatin. It also suggested that PARP-1 might be involved in cisplatin-resistance of ovarian cancer cells.