VEGF siRNA降低人肝癌细胞株SMMC7721的致瘤性

本研究应用RNA干扰（RNAi）技术高效抑制VEGF的表达，明显降低了人肝癌细胞株SMMC7721的致瘤性。化学合成针对人VEGF基因的siRNA，体外瞬时转染人肝癌细胞株SMMC7721，RT-PCR和Elisa法检测表明VEGFsiRNA实验组与对照组相比，细胞内VEGFmRNA表达下降了76．16％，VEGF分泌蛋白表达则下降了96．28％，而MTT法结果显示VEGFsiRNA对SMMC7721细胞增殖没有明显作用。体内实验中，不同时间对荷SMMC7721细胞瘤裸小鼠进行siRNA直接瘤内注射，同时测量瘤体积，最后取瘤块进行组织切片观察并进行分子生物学分析，结果显示，与对照组相比，VEGFsiRNA实验组肿瘤体积明显缩小，瘤内出现细胞坏死，同时肿瘤组织中VEGFmRNA和蛋白表达水平均明显降低。

REDUCTION OF TUMORIGENICITY OF SMMC7721 HEPATOMA CELL LINE BY VEGF siRNA

In this study the small interfering RNA(siRNA) targeting human VEGF effectively inhibited the expression of VEGF in human hepatoma cell line, SMMC7721, and could dramatically decrease the tumorigenicity of SMMC7721 s.c. xenograft tumor. Chemically synthesized siRNA targeting VEGF was transiently transfected into SMMC7721 cells by lipofectamine, RT-PCR and Elisa analysis suggested that the expression of VEGF mRNA and secreted protein in SMMC7721 cells with VEGF siRNA transfection were suppressed with inhibition rates of 76.16% and 96.28% respectively compared with negative control, but the growth rate of SMMC 7721 cells with VEGF siRNA transfection was the same as the control cells. In vivo test, siRNA was injected directly into implanted tumors and the tumors volume were calculated at different time interval. Result showed that VEGF siRNA greatly inhibited the growth of tumors tissues, which was consistent with decrease of VEGF mRNA and protein compared with control. In addition, the VEGF siRNA-treated group exhibited obvious signs of necrosis compared with control.