脂质体介导VEGF反义寡核苷酸对肺癌微血管密度及VEGF表达的抑制作用

Influence of antisense VEGF oligodeoxynucleotides formulated in cationic liposome on microvessel density and VEGF expression of lung cancer

背景与目的血管内皮生长因子(vascularendothelialgrowthfactor,VEGF)在肿瘤的血管形成和瘤细胞浸润等生物学行为中发挥了重要作用。本研究的目的是探讨脂质体介导的VEGF反义硫代寡核苷酸对C57BL/6小鼠Lewis肺癌微血管密度及VEGF表达的抑制作用。方法40只C57BL/6小鼠右腋皮下接种Lewis肺癌细胞后,随机分为4组:VEGF反义寡核苷酸组(ASODN)、VEGF正义寡核苷酸组(SODN)、VEGF错义寡核苷酸组(MODN)及对照组,前三组分别皮下注射经脂质体包裹的ASODN、SODN及MODN进行治疗,对照组只注射脂质体,每周2次,连续4周。观察各组小鼠肿瘤的生长情况,测量肿瘤体积。光学显微镜和电子显微镜下观察肿瘤组织形态学改变及超微结构变化。免疫组化及RT-PCR法检测微血管密度、VEGF蛋白及VEGFmRNA表达水平。结果对照组瘤重为(7.83±0.78)g,ASODN组瘤重为(4.49±0.43)g(P<0.01);SODN组瘤重为(7.73±0.69)g,MODN组为(7.78±0.75)g,与对照组比较差异均无统计学意义(P>0.05)。ASODN组、SODN组、MODN组抑瘤率分别为42.6%、5.1%、3.2%。ASODN组VEGF蛋白、VEGFmRNA表达水平和MVD均明显低于对照组、SODN组及MODN组(P<0.01)。结论肿瘤原位注射反义VEGF硫代寡核苷酸能降低肺癌微血管密度及VEGF的表达,进而抑制肿瘤的生长。

Background and objective Vascular endothelial growth factor （VEGF） is known to be one of the most important factors for angiogenesis and tumor cell infiltration. The aim of this study is to determine the influence of phosphorothioate-modified antisense VEGF oligodeoxynucleotides （ASODN） formulated in cationic liposome on microvessel density （MVD） and VEGF expression of lung cancer. Methods Lewis lung carcin-oma model was established by subcutaneous injection of Lewis lung carcinoma cells into 40 C57BL/6 mice. Within 24 h after inoculation, mice were randomly assigned to four groups treated with ASODN, sense oligodeoxynucleotides （SODN）, mismatch oligodeoxynucleotides （MODN）, or liposome alone respectively, twice a week for 4 weeks. The weight and volume of subcutaneous tumors were measured. The morphological and ultrastructural changes of tumor ceils were observed under microscope and electron microscope. MVD and expression of VEGF protein and VEGF mRNA were detected by immunohistochemical staining and RT-PCR. Results The tumor weight in the control group was （7.83±0. 78） g, and （4.49±0.43） g in the ASODN group （P〈0.01）. The inhibition rate of tumor growth in the ASODN, SODN and MODN groups was 42.6%, 5.1% and 3. 2% respectively. MVD and expression of VEGF protein and VEGF mRNA were decreased markedly in the ASODN group compared to the other three groups （P〈0.01）. Conclusion The resuits demonstrate that MVD and VEGF expression of lung cancer can be inhibited by VEGF ASODN injected into tumor tissue in C57BL/6 mice.