过表达Mfn2对人乳腺癌裸鼠移植瘤血管表皮生长因子受体的影响

EFFECTS OF MFN2 GENE OVEREXPRESSION ON EGFR EXPRESSION AND ANGIOGENESIS OF A HETEROLOGOUS GRAFT MODEL FOR HUMAN BREAST INFILTRATING DUCT CARCINOMA IN NUDE MICE

目的探讨过表达线粒体融合素-2(Mitofusin-2,Mfn2)对表皮生长因子受体(Epidermal Growth Factor Receptor,EGFR)表达的影响及对人乳腺癌裸鼠移植瘤生长、血管形成的影响。方法分别构建稳定转染空质粒pEGFP-N1(MCF-7 pEGFP-N1)及转染Mfn2质粒的pEGFP-Mfn2(MCF-7 pEGFP-Mfn2)的MCF-7细胞稳系。分别将人乳腺癌细胞MCF-7、MCF-7 pEGFP-N1、MCF-7 pEGFPMfn2接种于裸鼠右侧乳房垫内,观察裸鼠生长状况,每周两次测量肿瘤大小,绘制肿瘤生长曲线。5周后处死裸鼠,采用免疫组化验证肿瘤Mfn2蛋白的表达并检测CD34来观测肿瘤微血管密度(MVD),检测EGFR蛋白的表达情况。结果 pEGFP-Mfn2组肿瘤明显小于pEGFP-N1组和对照组(P<0.05)。pEGFP-Mfn2组微血管数目明显小于pEGFP-N1组和对照组(P<0.05)。pEGFP-N1组EGFR的表达与对照组相比差异无统计学意义(P>0.05),与对照组、pEGFP-N1组相比pEGFP-Mfn2组EGFR的表达明显降低(P<0.05)。结论 Mfn2明显抑制人乳腺癌裸鼠移植瘤的生长。下调EGFR表达、减少微血管生成可能为其抗肿瘤机制。

Objective To investigate the antitumor angiogenesis activity of Mfn2 gene on a heterologous graft model for human breast infiltrating duct carcinoma in nude mice,and to investigate the relationship between the level of Mfn2 gene and the expression of epidermal growth factor receptor（EGFR）.Methods Human breast cancer MCF-7 cells steady infected with Mfn2 gene had been constructed.Western blotting was used to detect the overexpression of Mfn2 protein.Then the MCF-7 cells were injected subcutaneously into the breast pad of nude mice.Tumorigenicity and the growth of transplanted tumor in nude mice were observed.Growth curves were plotted based on mean tumor volume in each experimental group at the indicated time points.Meanwhile,the negative control group（NC group）which MCF-7 cells steady infected with PEGFP-N1 was set up.The expression of CD34（reflect the microvessel density of tumor）and EGFR were detected by immunocytochemistry.Results The tumor volume of the experimental group was smaller than the negative control group.The expression of CD34 of the experimental group was lower than the negative control group.The experimental group expressed low level of EGFR.Conclusions Mfn2 significantly inhibits the growth of human breast cancer xenograft in nude mice.Downregulation of EGFR expression and decrease the potential of angiogenesis may be the potential mechanism.