| Ovarian cancer is the most common gynaecological cancer, which threatens the health of women severely. The annual higher incidence is increasing. Due to the often asymptomatic nature of the early stages of the disease, most cases are not detected until the advanced stages. Consequently, the prognosis after diagnosis is poor and the 5-year survival rate is only about 30%-40%. Many researchers have tried to use different complementary treatment methods to ovarian cancer patients of after operation in order to find a better result of complementary treatment. Nowadays, chemotherapy is the most common complementary treatment method for ovarian cancer. Current recommendations suggest that first-line chemotherapy for ovarian cancer should involve platinum (Pt)-based therapy (cisplatin/ carboplatin) . Although a significant proportion of women respond to platinum-based chemotherapy, however, most patients develop resistance or refractory disease and require second-line therapy. Topotecan is one of drugs currently licensed for second-line therapy, and recent reviews suggest that it has emerged as a promising new antineoplastic agent in the treatment of a range of solid tumors and hematological malignancies. Its novel mode of action via topoisomerase I inhibition and lowcross-reactivity with existing agents offers a clear therapeutic option to patients with recurrent or refractory disease.Nowadays, with the rapid development of molecular biology, the research in tumorigenesis machinery of ovarian cancer has became a hot point for many biologist and tumorist. The activation of cancer gene and the silence of anticancer gene are the molecular basics of the tumorigenesis and tumor progression. Tumorigenesis and tumor progression are closely related to the cell apoptosis and abnormality of cell increase. Inhibitor of apoptosis protein (IAP) family plays an important role in the gene control of cell apoptosis. Survivin has recently been identified as a novel inhibitor of apoptosis by Ambrosini in 1997. Survivin belongs to IAP family because survivin contains a single baculovirus IAP repeat. Survivin blocks a common downstream part of two major apoptosis, the mitochondrial pathway and the death receptor pathway, by directly inhibiting terminal effector caspase-3 and caspase-7, and by interfering with caspase-9 activity. It also regulates the G2/M phase of the cell cycle by associating with mitotic spindle microtubules. Many studies showed that survivin has unique properties undetectable in normal adults tissues and overexpression in a variety of human cancers in vivo. This character shows its potential as a diagnosis and therapeutic target in cancer.Although studies indicated that survivin was a prognostic tumor marker, little is known about its potential role in ovarian carcinoma and the its expression correlated with the treating of chemotherapy drugs, DDP and TPT, respectively. Therefore, in this study we sought to evaluate the anticancer effects and investigate the changes in expression levels of survivin in epithelial ovarian cancer in vivo during cisplatin and topotecan treatment. The correlation between chemotherapy drugs and survivin expression is discussed and their potential prognostic value is dissected.Methods1. The human ovarian cancer cell line SK0V3 was maintained as monolayer cultures in Dulbecco's modified Eagle's medium(DMEM) supplemented with 10% fetalbovine serum. Cells were grown at 37°C in a humidified atmosphere of 5% CO2. Cells were determined to be free of Mycoplasma infection by testing at 3-month intervals.2. Twenty-four nude mice were subcutaneously implanted with human ovarian epithelial cancer cell lines SKOV3 on the back of nude mice, and were divided into 4 groups after 21 days which were treated by abdominal administration with normal saline, cisplatin, topotecan and cisplatin+topotecan respectively. All mice were sacrificed after treatment of 18 days. The volumes of the tumors and the weights of the mice were measured during the therapy. The tumor growth inhibiting rates of each groups were calculated, and the curves of tumor growth were done.3. HE staining was used to observe the pathological morphology of the transplanted tumors.4. Immunohistochemistry was used to analyze the changes in expression levels of survivin protein in each group.5. RT-PCR was used to analyze the changes in expression levels of survivin mRNA in each group.6. Statistical analysis: All statistical analysis was performed using the SPSS 11.0 software package. Associations between the variables were tested by /* test , Wilcoxon signed t test. All P represent two-sided tests of statistical significance. A value of a = 0. 05 was considered statistically significant. Data are presented as mean ± SD.Results1. Significant differences in average tumor volumes and tumor growth inhibition rates were found between the treatment group and the control group(p<0.05).The tumor volumes were significantly less and the growth inhibiting rates of tumor were significantly higher than the other 3 groups in combination group (p<0.001). There were no obvious differences between the cisplatin group and the topotecan group (P>0.05).2. Compared with control group, the tissue section with HE staining showed greater decrease in tumor cell numbers, increased necrosis areas and pathological changes in other 3 chemotherapy groups. Especially in combination group the pathological changes is more obvious.3. The survivin protein expression in the TPT group and the DDP+TPT group which is (70.83±5.84)% and (68.67±4.89)% respectively is obviously decreased compared with that in the control group and the DD group (PO.05), but there were not statistically significant different between the TPT group and the DDP+TPT group, and between the DDP group and the control group (P>0.05).4. Survivin mRNA expression was significantly lowered in both topotecan group and cisplatin+topotecan group, as compared with that in the control group and the DDP group(.P<0.001). But there were not statistically significant different between the TPT group and the DDP+TPT group, and between the DDP group and the control group CP>0.05).Conclusion1. The combined application with cisplatin and topotecan had stronger inhibition on tumor growth than used alone, and they had a synergic anticancer effect to ovarian cancer.2. The experiment firstly showed topotecan had the effect of reducing the expression of survivin protein and mRNA in ovarian carcinoma xeocraft tumor in nude mice, which is helpful for the further recognition of the mechanism of topotecan.
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