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目的探讨小鼠巨噬细胞金属弹力酶(MME)对小鼠原位结肠癌生长、微血管生成及血管内皮生长因子(VEGF)表达的影响。方法扩增编码MME基因结构域Ⅰ和Ⅱ的cDNA片段,构建真核细胞表达载体pcDNA3．1-MME并转染小鼠CT-26结肠癌细胞。建立MME转染组及对照组小鼠原位结肠癌种植模型,观察MME对原发性结肠癌生长的影响,采用免疫组化及原位杂交方法检测肿瘤组织中VEGF的表达和微血管密度(MVD)。结果重组MME蛋白在CT-26细胞内成功表达并具有酶活性。MME转染组原发结肠癌的体积明显小于对照组(P＜0．001),结肠癌组织中的MVD值明显低于对照组(P＜0．01)。VEGF mRNA和蛋白水平在MME转染组中均显著低于对照组(P＜0．05)。结论转染入小鼠结肠癌细胞的MME基因通过抑制新生血管的生成,从而起到抑制原位结肠癌生长的作用。MME和VEGF都与肿瘤的血管生成密切相关,它们之间的平衡可能调控着肿瘤中新生血管的生成。
Objective To investigate the effects of mouse macrophage metalloemerase (MME) on the growth, angiogenesis and the expression of vascular endothelial growth factor (VEGF) in mouse colon carcinoma in situ. METHODS: cDNA fragments encoding the domain I and II of the MME gene were amplified, and the eukaryotic cell expression vector pcDNA3.1-MME was constructed and transfected into mouse CT-26 colon cancer cells. To establish the model of orthotopic colon cancer implantation in mice transfected with MME and control group, the effect of MME on the growth of primary colon cancer was observed. The expression of VEGF and the microvessel density (MVD) were detected by immunohistochemistry and in situ hybridization ). Results The recombinant MME protein was successfully expressed in CT-26 cells and had enzyme activity. The volume of primary colon cancer in the transfected group was significantly smaller than that in the control group (P <0.001). The MVD in colon cancer tissues was significantly lower than that in the control group (P <0.01). The levels of VEGF mRNA and protein in the transfected group were significantly lower than those in the control group (P <0.05). CONCLUSION: The MME gene transfected into mouse colon cancer cells can inhibit the growth of colorectal cancer by inhibiting angiogenesis. Both MME and VEGF are closely related to tumor angiogenesis, and the balance between them may regulate the formation of neovascularization in tumors.