突变型K-ras siRNA抑制肺癌A549细胞的增殖和迁移并诱导细胞凋亡

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。

Mutant K-ras specific siRNA inhibits proliferation, migration and induces apoptosis of lung cancer A549 cells

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 blot-ting. 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 ex-pression 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.