AdH1-siRNA/VEGF联合化疗对小鼠Lewis肺癌的治疗作用

Therapeutic effect of AdH1-siRNA/VEGF combined with chemotherapy in mice with Lewis lung cancer

目的研究腺病毒介导的干扰核糖核酸(RNAi)联合化疗对小鼠肺癌的治疗作用。方法构建表达小鼠血管内皮生长因子(VEGF)序列特异性小干扰RNA(siRNA)复制缺陷型腺病毒(AdH1-siRNA/VEGF)。建立小鼠Lewis肺癌的动物模型,随机均分成五组,分别实施环磷酰胺化疗(A组)、腺病毒治疗(B组)、空载腺病毒处理(C组)、AdH1-siRNA/VEGF病毒联合环磷酰胺处理(D组)和生理盐水对照(E组)。定期测量肿瘤体积,ELISA方法测定VEGF表达,免疫组化法检测肿瘤微血管密度(MVD)。结果 AdH1-siRNA/VEGF可以显著下调肿瘤细胞VEGF的分泌。A、B和D组肿瘤的体积小于E、C组(P<0.05)。B组血清VEGF水平低于C、E组(P<0.01);B、D组肿瘤的MVD低于C、E组(P<0.01)。结论重组腺病毒介导的siRNA技术在体外和体内能有效地下调VEGF的表达,减少肿瘤内微血管生成、抑制肿瘤生长;RNAi联合化疗抗肿瘤活性效果更好。

Objective To study the therapeutic effect of AdHI-siRNA/VEGF （vascular endothelial growth factor） combined with chemotherapy in mice with Lewis lung cancer, Methods A replication-defective recombinant adenovirus AdHI-siRNA/VEGF targeting mouse VEGF was constructed using the homologous recombination technique. After established Lewis lung carcinoma models,40 C57BL/6 mice were randomly and egually divided into 5 groups of A（chemotherapy）, B （treated with AdHI-siRNA/VEGF）, C （treated with AdCMV/GFP）, D （chemotherapy plus AdH1- siRNA/VEGF） and E（normal saline control）. The tumor volume was measured. The expressions of VEGF in cell culture medium and serum after infection of the indicated adenovirus were detected by indirect ELISA and the microvessel density（MVD） of tumor was counted under the microscopy after immunohistochemical examination. Results AdHI-siRNA/ VEGF could specifically decrease the secretion of VEGF in tumor cells. The tumor volume was smaller in groups of A,B and D than that in groups of E and C（P%0. 05）. Serum level of VEGF was lower in group B than that in groups of C and E（P%0. 05）. The number of MVD was less in groups of B and D than that in groups of C and E （P^0. 01）. Conclusion The recombinant adenovirus-mediated siRNA can obviously downregulate VEGF expression in vitro and in vivo, which reduces the angiogenesis and growth of tumors, RNAi combined with chemotherapy has a synergistic inhibition effect on tumors.