人血管生成素-1基因转染对胃癌细胞体内致瘤力及血管生成的影响

目的　研究人血管生成素 1 (Ang1 )基因转染人胃癌细胞系SGC790 1后 ,对肿瘤细胞生物学特性以及对小鼠体内致瘤力和血管生成的影响 ,探讨其在胃癌发生及血管生成中的作用。方法构建重组正、反义Ang1真核表达载体 ,采用脂质体转染法 ,将重组载体转染人胃癌细胞系SGC790 1 ,分别得到正、反义载体稳定转染的细胞株 7Ang1 +和 7Ang1 - ,并以半定量PCR及Westernblot方法鉴定转染效果。以MTT比色试验绘制生长曲线 ;以流式细胞仪检测细胞周期分布。通过裸鼠成瘤实验 ,比较转染前后小鼠体内成瘤能力的差别 ,并检测肿瘤组织微血管密度 (MVD) ,判定血管生成程度。结果　 7Ang1 -组细胞Ang1在蛋白及mRNA水平的表达均下调。体内成瘤实验结果显示 ,空载体对照组、7Ang1 +组和 7Ang1 -组瘤体的平均重量 ( x±s)分别为 6 2 4 .0 0± 77.78,6 5 2 .6 7± 1 32 .0 7和2 93.0 0± 95 .5 4 ,7Ang1 -组的细胞成瘤性显著低于 7Ang1 +组和空载体对照组 (P <0 .0 1 )。空载体对照组、7Ang1 +组和 7Ang1 -组肿瘤组织的MVD( x±s)分别为 8.4 4± 1 .33,8.78± 1 .92和 6 .0 0± 1 .73,7Ang1 -组细胞的血管生成显著减少 (P <0 .0 1 )。结论　Ang1在胃癌形成和发展中可能通过诱生血管起促进作用 ,通过反义技术可部分阻断这种作用。

Effect of human angiopoietin-1 on tumorigenesis and angiogenesis of gastric cancer

OBJECTIVE: To investigate the role of human angiopoietin-1 (Ang1) in tumorigenesis and angiogenesis of human gastric cancer cell line SGC7901 in nude mice. METHODS: Recombinant human Ang1 sense or antisense eukaryotic expression vectors were constructed, and transfected by lipofectin into human gastric cancer line SGC7901. Stable transfectants were obtained respectively, namely 7Ang1+ for sense, 7Ang1- for antisense, and 7901P for empty vector transfected cells. Semiquantitative PCR and Western blot were employed to testify the transfection efficiency. Cell growth curve and cell cycle were observed by MTT assays or flow cytometry. In in vivo study, growth of SGC7901 xeno-transplant was observed in BALB/c nude mice. Microvessel density (MVD) was analyzed by immunohistochemistry for Factor VIII staining. RESULTS: Stably transfected cell lines were established and decreased expression of Ang1 protein and mRNA in the antisense transfected SGC7901 cells was achieved. Tumorigenesis of 7Ang1- cells on day 30 days was significantly inhibited with decreased MVD as compared to that in 7901P and 7Ang1+ cells (P < 0.01). CONCLUSION: Angiopoietin-1 plays an important role in tumorigenesis and angiogenesis of gastric cancer which can be partially abrogated by antisense technique.