目的:构建靶向Kras的siRNA，研究Kras siRNA对Kras基因突变型肺癌细胞A549及Kras野生型小细胞肺癌细胞NCIH446生长和迁移的抑制作用。方法:设计并人工合成4条Kras siRNA（针对野生型Kras基因的Kras siRNA1~ Kras siRNA3；针对突变型Kras 基因的Kras siRNA4），并分别转入A549和NCIH446细胞。RTPCR和Western blotting检测不同Kras siRNA对Kras mRNA和蛋白表达的影响，MTT法检测不同Kras siRNA对A549和NCIH446细胞增殖的抑制作用，Transwell实验和Hoechst 33258染色检测Kras siRNA对细胞迁移和凋亡的影响。结果:靶向突变型Kras的Kras siRNA4能特异性抑制A549细胞中Kras的表达，但对Nras和Hras的表达没有影响。Kras siRNA4抑制A549细胞的增殖，但不影响含野生型Kras基因的NCIH446细胞的增殖。Kras siRNA4还能诱导A549细胞凋亡、抑制A549细胞迁移。结论: 针对突变型Kras基因的siRNA可特异性抑制Kras突变型肺癌细胞的增殖和迁移，并诱导该细胞凋亡，Kras siRNA可望用于Kras突变型肿瘤特别是肺癌的个体化治疗。

Objective:To construct Krastargeted siRNAs (Kras siRNA) and to investigate the inhibitory effects of Kras siRNAs on the growth and migration of lung cancer A549 cells (containing mutant Kras gene) and NCIH446 cells (containing wildtype Kras gene). :Methods: :Four Kras siRNAs (Kras siRNA1~Kras siRNA3 targeting wildtype Kras and Kras siRNA4 targeting mutant Kras) were designed and artificially synthesized; they were used to transfect A549 cells and NCIH446 cells. The expressions of Ras mRNA and protein were examined by RTPCR and Western blotting. The inhibitory effects of Kras siRNAs on the proliferations of A549 and NCIH446 cells were determined by MTT assay. The effects of Kras siRNAs on the cell migration and apoptosis were observed by Transwell assay and Hoechst 33258 staining, respectively. :Results: :Mutant Krastargeted siRNA (Kras siRNA4) specifically inhibited the Kras expression but had no influence on Hras and Nras expression in A549 cells. Kras siRNA4 inhibited the proliferation of A549 cells but did not inhibit that of NCIH446 cells, which contained wild type Kras gene. Kras siRNA4 also induced apoptosis and inhibited migration of A549 cells. :Conclusion: :Mutant Krastargeted siRNA4 can inhibit the proliferation, migration and induce apoptosis of A549 cells. It may be a potential and personalized drug for the treatment against lung cancer containing mutant Kras gene.

国家高技术研究发展计划（863计划）课题资助项目（No. 2008AA02Z135）；福建省发改委课题资助项目（2008第3批26号）