| Ovarian cancer, mainly includes serous carcinoma, mucinous carcinoma, endometrioid carcinoma, metastatic carcinoma etc., is one of the highest mortality of gynecological malignant tumors. It is of high degree of malignancy and the incidence is on the rise. Although the tumor cytoreductive therapy and chemotherapy has reached a great achievement, the 5-year survival rate of ovarian cancer has not improved significantly. Therefore, many scholars have conducted in-depth research in the level of gene regulation in terms of tumor growth and metastasis of the biological behavior. The change in a number of signal transduction iters has been playing a role in the emergence and development of tumor. Recently, biological treatment technology has become the focus on the treatment of ovarian cancer. STAT3 (signal transduction and activators of transcription 3) is one of the most important members of STATs. The iter induced by STAT3 accept growth factors, cytokines and other extracellular signal-stimulation, acting on the specific nucleus DNA fragment and regulating the transcription of target gene. The activation of the iters could lead to abnormal cell proliferation and malignant transformation. Silver et al confirmed that STAT3 has a high level of expression in a variety of ovarian cancer cell line (OV-1063, MDAH 2774, Caov-3), which make it a novel solution in ovarian cancer diagnosis and treatment. RNA interference technology is the way of artificially introducing the double-stranded RNA (dsRNA), of the homologous sequence as the target gene, inducing the mRNA degradation of endogenous target gene, preventing gene expression . This study used established a subcutaneous tumor model with nude mice to observe the influence of siRNA-STAT3 in terms of transplanted ovarian cancer growth and tumor cell apoptosis.Objective:To study the growth inhibition effect of ovarian cancer in athymic mouse by pSilencer1.0-U6-siRNA-STAT3 recombinant plasmid.Materials and Methods:1*10^8/ml SKOV3 cells were correspondingly inoculated into the back of subcutaneous tissue of 15 nude mice to build ovarian cancer xenograft model in nude mice. When the average tumor volume (V = L×W2×0.52)has reached up to 8mm, we randomly divided the nude mice into three groups, i.e. saline control group (intratumoral injection of normal saline); empty plasmid control group (intratumoral injection of empty plasmid) and the recombinant plasmid group (intratumoral injection of siRNA-STAT3 recombinant plasmid). The plasmid injection volume was controlled as 20μg/mouse in each of the group. After the injection, the electricity transfection was applied to the injection site so that the efficiency of the transfection was enhanced. The injection was performed 5 times, 5 days/time. The nude mice were executed on the 36th day, after which the tumor was instantaneously and completely stripped, detected the gene expression of STAT3,survivin,c-myc,VEGF,cyclin-D1 by Western Blot and immunohistochemistry,embedded in paraffin and sliced to perform HE coloration and TUNEL detection.Results:The growth of transplantation tumor had an obvious suppression after transfection(P<0.05) .The results of Western Blot and immunhistochemistry confirm that the specificity of pSilencer1.0-U6-siRNA-STAT3 inhibit the expression of STAT3 in tumor tissue. In the two controlled groups there is no significant difference in the expression of STAT3,survivin,c-myc,VEGF,cyclin-D1, but that of the recombinant plasmid group remarkably reduces,indicating different inhibition effects compared with those two controlled groups (P <0.05). The result demonstrats that siRNA-STAT3 has a specific inhibitory effect on STAT3. The results show that the STAT3 expression in the cells of recombinant plasmid group has significantly reduced. HE staining showed the tumor cells of recombinant plasmid group have nuclei pyknosis, fragmentation and other signs of apoptosis. TUNEL test results confirm that tumor tissue which application of siRNA-STAT3 have a large amount of apoptotic cells.Conclusions:pSilencer1.0-U6-siRNA-STAT3 recombinant plasmid can obviously inhibit the ovarian cancer in athymic mouse. The growth velocity of transplantation tumor steped down, the protein level of STAT3,CyclinD1,VEGF,Survivin,c-myc was decreased, the apoptosis was apparent. |
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