A Study On The Apoptosis Of Cervical Cancer And Ovarian Cancer Cells Induced By INOS Inhibitor And The Regulation Of P53 Pathway

BackgroundCervical and ovarian cancers are very common in gynecology and seriously threaten women’s health. After primary surgery, systemic chemotherapy is the current standard treatment for advanced cervical and ovarian cancers. Cisplatin(DDP) and its derivatives are first-line drugs, being wildly used in gynecology cancers, whereas the toxicity and resistance are the major hurdles in successful treatment. Inducible nitric oxide synthase (iNOS) and p53status are key determinants of cells fate in human cervical and ovarian cancer cells. However, whether inhibiting iNOS may affect cells proliferation and the corresponding changes of p53pathway remain yet to be determined.ObjectiveThis study investigated the iNOS inhibitor combined with DDP for cervical and ovarian cancer cells growth inhibition, and further study the molecular mechanism of regulation of the p53pathway.MethodsStudies were carried out in cervical cancer cell line SiHa and epithelial ovarian cancer cell line OVCAR-3. Cells were challenged with N-(3-(aminomethyl)benzyl)acetamidine (1400W) or DDP for24h or48h, and set the control group,1400W group, DDP group and1400W+DDP group. Viability was measured by MTT and flow cytometry. Apoptosis was assayed by caspase-3activity. P53, MDM2and DNA-dependent protein kinase (DNA-PK) protein expression were analyzed by Western-blot and corresponding mRNA expression by real time PCR. Statistical analysis was performed by SPSS17.0software using one-way analysis of variance. A value of P<0.05was considered statistically significant.ResultsPretreatment with1400W enhance the DDP induced cell proliferation inhibition in SiHa cells relative to OVCAR-3cells. Meanwhile, caspase-3activity was accelerated significantly in both cell lines. Furthermore, p53expression of the two cell lines were both greatly inhibited in1400W+DDP groups than other three groups. In SiHa cells, MDM2expression increased significantly in1400W+DDP groups, while it was decreased in OVCAR-3cells in contrary. The study also indicated that DNA-PK expression of the two cell lines was significantly higher in1400W+DDP groups than in DDP groups. And the changes of proteins were more significant than mRNA.Conclusions1.1400W could strengthen the cytotoxicity of DDP in SiHa significantly, whereas without obvious effects in OVCAR-3.2.1400W induced apoptosis in both cervical and ovarian cancer cell lines by different mechanisms. In SiHa cells, down-regulation of p53was mainly due to increased MDM2expression whereas in OVCAR-3cells it did not depend on MDM2.