siRNA沉默血管VEGFR-1基因对乳癌生长抑制作用

目的探讨应用化学修饰的小干扰RNA（siRNA）沉默人裸鼠乳癌移植瘤新生血管中的血管内皮生长因子受体-1（VEGFR-1）基因对移植瘤生长的影响。方法将组织瘤块接种于裸鼠右侧第二对乳腺的脂肪垫内，肿瘤长至一定大小时，随机分为对照（A）组、转染试剂对照（B）组、siRNA治疗（C）组。于肿瘤局部分别注射PBS溶液、Lipofectamine 2000^TM转染试剂和Lipofectamine 2000^TM转染试剂包裹的VEGFR-1 siRNA。22d后处死全部动物，取肿瘤，测其大小；用RT—PCR及蛋白印迹法检测乳癌组织VEGFR-1基因的表达。结果与A、B组比较，C组移植瘤增长趋势受到明显抑制（F=158．18、55．72，q=11．39、14．05，P〈0．01）；RTPCR结果表明，与A、B组比较，C组明显下调了VEGFR1 mRNA的表达（F=385．06，q=33．43，34．52，P〈0．01）；蛋白印迹法结果亦显示，C组明显下调了VEGFR-1 mRNA的表达（F=114．11，q=9．31，20．75，P〈0．01）。A组和B组各指标差异无显著性（P〉0．05）。结论化学修饰的siRNA介导的RNAi可以降低人乳癌裸鼠移植瘤血管中VEGFR-1的表达，抑制血管生成进而抑制肿瘤的生长，是潜在的肿瘤治疗的新方法。

THE EFFECT OF RNA SILENCING VEGFR-1 GENE ON INHIBITION OF BREAST CANCER

Objective To study the effect of VEGFR 1 gene in new vessels of implanted human breast cancer in nude mice of chemically modified siRNA on the growth of implanted tumor. Methods Tumor tissue was implanted into the fat pad of mammary gland of the nude mice, which were randomized to groups A （control group）, B （transfeeting agent group） and C （siRNA therapy group） when the tumor reached a certain size. The tumors were respectively injected with PBS, transfeeting agent （Lipofectamine 2000TM） and transfecting agent （Lipofectamine 2000TM） with VEGFR-1 siRNA. All the animals were killed after 22 days. The tumors were removed, the size measured. The expression of VEGFR 1 gene in cancer tissue was detected by RT-PCR and Western blotting. Results Compared with groups A and B, the growth of tumor in group C was obviously suppressed （F=158.18, 55.72; q= 11. 39,14.05; P〈0.01）. RT-PCR result indicated that the expression of VEGFR-1 mRNA in group C was markedly down-regulated as compared with groups A and B （F=385.06;q=33.43,34.52;P〈0.01）, and the Western blotting also revealed the same result （F= 114.11 ;q= 9.31,20.75 ; P〈0.01）. No significant changes of above items were noted in groups A and B （P〉0.05）. Conclusion RNAi mediated by chemically modified siRNA can decrease VEGFR-1 gene expression in vessels of implanted tumors in nude mice, inhibit the growth of new vessels and tumors, which is a potential therapy for tumor.