Treatment with Tie2-siRNA in combination with carboplatin suppresses the growth of Ishikawa human endometrial carcinoma cell xenografts in vivo

It is well-known that tumor angiogenesis is important in cancer development, and studies on blocking angiogenesis to treat tumors have become one of the most promising and active fields in anticancer research. The present study investigated the effect of siRNA targeting the tyrosine kinase receptor 2 (Tie2) gene in combination with carboplatin in a mouse model of endometrial carcinoma in an attempt to elucidate the role of Tie2 in the carcinogenesis and progression of endometrial carcinoma via angiogenesis, in order to establish a basis for the development of complementary molecule targeting and chemotherapeutic actions. Ishikawa cells were used to establish a human endometrial carcinoma nude mouse tumor xenograft model. Tie2-siRNA (20 μg/mouse) and/or carboplatin (25.0 mg·kg(−1)) were administered as the treatment strategy. Real-time PCR and western blotting were used to evaluate the expression levels of Tie2 mRNA and protein and immunohistochemistry was used to assess the vessel density of the tumor tissues. The present data demonstrated that Tie2-siRNA and/or carboplatin were able to suppress the growth of endometrial xenografts in vivo and attenuate the expression of Tie2 mRNA and protein, as assessed by real-time PCR and western blotting. Furthermore, immunohistochemical assessment showed that the vessel density of the tumors decreased with treatment. The present results suggest that treatment with Tie2-siRNA or carboplatin alone was able to inhibit the growth of human endometrial carcinoma nude mouse xenografts markedly and decrease the expression of Tie2. The combination of Tie2-siRNA and carboplatin increased the therapeutic effect of carboplatin which may eliminate the tumor microenvironment, increase the apoptosis of tumor cells, normalize the abnormal tumor vessels and increase the efficiency of chemotherapy for endometrial carcinoma with carboplatin. The synergy of Tie2-siRNA in combination with carboplatin may involve the regulation of other angiogenesis and metastasis pathways.