Study On The Mechanism Of Valproic Acid Enhance The Killing Effect Of Cisplatin On Human Ovarian Cancer HO-8910 Cell

[Background] The incidence of ovarian cancer in the third Of female genital cancer. Be lower than cervical and uterine cancer.But ovarian cancer has the highest death rate in Various types of gynecologic cancer. It had serious threat to the life of women. The Standard chemotherapy of platinum-based was Widely used in ovarian cancer. It was reported that Ovarian cancer patients after cytoreductive surgery and Combined chemotherapy, the remission rate can up to 60%-80%. But in actual clinical, the 5 year survival rate of Patients who with advanced ovarian cancer still rather low. Mainly due to the patients with ovarian cancer initial response to platinum chemotherapy, 80% appear chemotherapy resistance.So, overcome drug resistance in ovarian can cer,improve the efficacy of ovarian cancer is a Urgent problem in refractory ovarian cancer treatment. In recent years, studies have shown that the incidence of ovarian cancer is a combined action of the epigenetic and genetic changes. The tumor formation has relate with Chromatin histone lysine residues nucleosome acetylation and deacetylation. Responsible for histone acetylation and deacetylation are two functional antagonism of protease: Histone acetyltransferase and Histone deacetylase ,their dynamic equilibrium control chromatin structure and gene expression. Histone deacetylase inhibitors by adjusting the balance between HAT and HDAC inhibition of cancer-causing gene, activation of tumor suppressor genes, promoting tumor cell apoptosis.valproic acid,as a traditional anti-epileptic drugs, has a wide range of drug safety history,and Perfect pharmacokinetics, Side effects, Well tolerated in patients. In recent years, had found that histone deacetylase inhibitorsactivity. In leukemia, prostate cancer, breast cancer and other cancer research. VPA has proven that anti-tumor cell proliferation, induce apoptosis, causing cell cycle arrest and so on. This study examined the cell-killing effects of VPA combined DDP on human ovarian cancer HO8910. [Objectives] To observe in vitro and vivo,the Histone deacetylase inhibitor sodium valproate individual effect and the effect of it combine with Cis-Dichlorodiammineplati num for human ovarian cancer cell line HO8910 cells proliferation, cycle arrest and apop tosis. Detection of changes in gene expression levels and Vivo inhibition of tumor growth inhibition situation.Investigate the synergic action mechanism of VPA and DDP.Provide new ideas and theoretical basis for improve refractory ovarian cancer clinical efficacy.[Methods]①MTT assay different concentrations of VPA, DDP single drug and their combined effect on the proliferation HO8910 cell growth inhibition;②Optical microscope observe HO8910 cell morphological change on the effect of VPA, DDP single drug and Their combined;③Hoechst 33258 fluorescent staining assay apoptosis morphological changes under the action of each group drugs;④Apoptosis was detected by flow cytometry;⑤Flow cytometry cell cycle blockade;⑥R T-PCR assay mRNA levels expression changes of P53, P21^waf/cip1 gene;⑦Western Blot detection of Ac-H3, P53, P21^waf/cip1, CyclinD1, Stat3 gene expression changes in protein level;⑧Nude mice experiments and the inhibition of tumor growth observed[Results]①VPA can inhibit cell growth HO8910, the inhibition of VPA United DDP treatment was higher than single-drug treatment, Significant difference between groups (P< 0.05 ) ,and in a dose and time-dependent.;②Cell morphology observed under light microscope, VPA treated cells shows smaller in size and elongated spindle , membrane shrinkage, poor adherence, VPA + DDP group changed more significantly;③Hochest 33258 staining showed that, After treatment cells showed significant nuclear fragmentation, karyopycnosis, VPA combined DDP cell apoptosis was significantly changed compared with single agent;④HO8910 VPA monotherapy can induce apoptosis,and apoptosis significantly enhanced after the VPA ioint DDP;⑤VPA arrest ovarian cancer HO8910 cell cycle in G0/G1 phase and VPA + DDP group G1/G2 phase cells increased, S phase cells decreased;⑥VPA and VPA joint DDP can significantly improve ovarian cancer HO8910 cells acetylation of histone H3 level, increased p53, p21^waf/cip1 the mRNA and protein levels, reduce CyclinD1, Stat3 protein expression, significant differences between the groups (P<0.05);⑦The treated group nude mice subcutaneous tumor growth rate was significantly slower than the control group, VPA+DDP treatment group has the smallest tumor volume ,between groups was statistically significant (P<0.05).[Conclusion] VPA can collaborate DDP on the killing effect of ovarian cancer HO8910.The mechanism may be related to VPA increased the level of histone acetylation, increased P53, P21 waf/cip1 gene expression and down Stat3, Cyclin D1 expression, triggering cell cycle arrest and apoptosis.