| Background and ObjectiveOvarian cancer, consisting mainly of epithelial ovarian carcinoma(EOC),is the main reason for female gynecological tumor related death,is also the most lethal gynecologic malignancy. In China, the crude death rate of ovary cancer was 7.91/100,000 and the age-adjusted rate was 5.35/100,000 overall during period 1999-2010[1].Due to the lack of specific indicators for early diagnosis and the pathogenesis of it is concealed, most EOC patients are diagnosed at advanced stages and current chemotherapy regimens are ineffective against advanced EOC due to the development of chemoresistance, making the treatment of the disease encountered unprecedented challenges[2]. Therefore, it is imminent to better understand the molecular mechanisms underlying acquired resistance, activity, progression of ovarian carcinoma, so as to find the specific, sensitive markers for early diagnosis and the molecular targeted drugs with less side effects.Recently, some scholars have found that Wnt/beta-catenin pathway which is very hot in the current research about tumor treatment, may be involved in the progression of ovarian cancer and chemotherapy drug resistance[3; 4]. Studies have shown that some protein which are the members of Wnt/beta-catenin pathway, have been expressed highly in ovarian epithelial carcinoma, such as extracellular signal protein Wnt-1, the core protein beta-catenin and protein transcribed by target genes c-myc, cyclinD1, moreover beta-catenin has been involved in the abnormal proliferation and metastasis of ovarian cancer cells. Therefore, if we can find out the inhibitors about any link in the Wnt/ beta-catenin pathway, the two worldwide problems about side effects of chemotherapy drugs and chemoresistance of cancers can be solved, this will bring hopes for each patient.Telomerase as the "guards" of telomere, has been proved highly expressed in malignant tumors at the end of last century, ovarian cancer which is the most lethal gynecologic malignancy is involved too, Murakami, etc. [5]had found that telomerase activity was detected in 23 of 25 malignant ovarian tumors(92%), moreover, tumor differentiation degree and the activity of telomerase present negative correlation, in their research on borderline-malignant tumors, benign tumors and malignant ovarian tumors. Recently, many scholars are trying to apply the specificity inhibitor of telomerase to the treatment of tumors, mainly focused on liver cancer, nasopharyngeal carcinoma, gastric cancer and ovarian cancer, etc., which has obtained certain achievements, but it is helpless for the acquired chemoresistance of tumors.As a kind of multifunctional protease, on the one hand, tankyrase can inhibit the activity of Tankyrase1/2 with its glycosylation function,so as to provide an acting site to telomerase and to maintain stability of the chromosomes, on theother hand, it can also can make Axin to be more stable, thus the degradation of beta-catenin will be more faster, which makes the Wnt/ beta-catenin pathway operated in forward direction. XAV939 as a targeted inhibitor of Wnt/ beta-catenin pathway was discovered by Huang,S. M, etc.[6] in 2009, aiming at inhibiting beta-catenin-mediated transcription,by using a quantitative chemical proteomic approach they found that it stimulates beta-catenin degradation by stabilizing axin, thus the degradation of beta-catenin might be accelerated.In this study, we observed the impact induced by XAV939(a inhibitor of Tankryases) on the proliferation, apoptosis and tankyrase, cyclin D1, beta-catenin expressed in cytoplasm/nucleus of human ovarian adenocarcinoma cell-SKOV3,aiming to provide new thread for resistance inversion of ovarian cancer and to find a new kind of targeted drugs for the therapy. Materials and methodsFirstly,we Cultured the SKOV3 cells to post-exponential phase in vitro,then added the correlative drugs to SKOV3 cells, including different concentrations of sole medication XAV939, cisplatin and united medication; then MTT assay and flow cytometry were used to detected the apoptosis rate and the cell cycle distribution of SKOV3 cells; finally, Western blot was used to evaluate the expression of tankyrase, cyclinD1 and beta-catenin in ovarian carcinoma cells(SKOV3) in vitro which have been treated by XAV939 under different concentrations for 48 hours.All analyses were performed using SPSS version 20.0. A P value < 0.05 was considered statistically significant. Results1. The inhibition effect of XAV939/DDP and on SKOV3 cell: With the increasing of XAV939/DDP concentration and with the extension of drug action time, the apoptosis rate of SKOV3 cells actually gradually increased, the strength of the inhibitory effect was positively related with the drug concentration and action time, exhibiting concentration-dependent and time-dependent manners(P <0.05).2. The chemosensitive effect of XAV939 when combined with DDP: SKOV3 cells were treated with combined DDP of different concentration and 0.8?M of XAV939 compound for 48 hours. The combined inhibitory effect at low concentration is more obvious than DDP alone. Moreover, the chemosensitivity of SKOV3 on DDP was imporved( IC50(DDP)=69.059?g/ml IC50( XAV939+DDP)=52.254?g/ml).3. The influence on cell cycle and apoptosis of SKOV3 by XAV939: In analyses of SKOV3 cultures by flow cytometry, with the increase of concentration and drug action time of XAV939, the presence of G0/Gl phase cell accounted for higher proportion than control team(P<0.05),and the percentage of S phase showed a trend of decline(P<0.05), exhibiting concentration-dependent manners.4. Influence on the expression of tankyrase, cyclinD1 and beta-catenin by XAV939 : According to the western blot test analysis,we examined the upregulated expressions of tankyrase, cyclinD1 and beta-catenin. At the same time, it revealed that tankrase, cyclinD1 and beta-catenin was significantly declined in cells under the influence of XAV939. Conclusion1,XAV939 or DDP could effectively inhibit the proliferation and induce apoptosis of ovarian cancer SKOV3 cells in vitro separately,but the function was weak and exhibiting concentration-dependent and time-dependent manners.2, Compared with the ettects of XAV939 or DDP separately at high concentrations, combination of XAV939 and DDP at low concentrations proved to be much more effective in the inhibition of the proliferation and induction of the apoptosis of ovarian SKOV3 cell line.3, XAV939 probably inhibit the proliferation of ovarian cancer cell line SKOV3 by down-regulating the expression of tankyrase and beta-catenin. |
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