小片断干扰RNA抑制保罗样激酶1基因的表达诱导胃癌细胞凋亡

目的 观察抑制保罗样激酶基因（polo like kinasel，plkl）表达对胃癌细胞——MKN45凋亡的诱导，探讨plk1基因对胃癌细胞增殖及生存力的作用。方法 化学合成小片断干扰RNA（siRNA）阻断MKN45细胞plkl基因的表达；实时定量PCR及Western blot检测干扰前后plk1 mRNA及蛋白质表达的变化；免疫荧光及激光共聚焦显微镜观察MKN45细胞微管改变，流式细胞仪检测MKN45细胞周期及凋亡的变化；Western blot检测pro-caspase3水平的变化。结果 经靶向plk1的siRNA作用后，plk1 siRNA mRNA及蛋白质表达明显下降；MKN45细胞纺锤体结构变得模糊，失去完整性；较多MKN45细胞呈现G2期细胞DNA含量（P〈0．05）；MKN45细胞在48、72h凋亡率较对照组明显上升（P〈0．05）；伴随pro-caspase3水平在72h出现下降。结论 抑制plk1基因表达可导致MKN45细胞凋亡，凋亡机制可能通过caspase3途径；plk1基因对胃癌细胞增殖及存活起着至关重要的作用。

Inhibition of polo like kinase gene expression induces apoptosis in gastric cancer cells

Objective To observe the effect of inhibition of polo like kinase1(plk1) gene expression on apoptosis induction in gastric cancer cell line-MKN45 and discuss the vital role of plk1 proliferation and viability of gastric cancer cells. Methods The plk1 expression was inhibited by chemically synthesized siRNA. The plk1 mRNA and protein level were respectively measured by real-time quantitative PCR and Western blotting. The spindle morphological change was observed by immunofluorescence staining and confocal microscopy. The change of cell cycle distribution and apoptosis rate was detected by flow-cytometry. Pro-caspase3 level was also detected by western blotting. Results After treatment by siRNA targeting plk1,plk1 mRNA and protein level decreased obviously,the cell mitotic spindle became obscure and lost cohesiveness,more MKN45 cells accumulated at G2/M phase(P< 0.05),apoptosis rate of plk1 siRNA treated MKN45 cells was higher than that of control cells at 48 h and 72 h(P< 0.05) with pro-caspase3 level decreasing at 72 h. Conclusions Inhibition of plk1 gene expression induces apoptosis in MKN45 cells through the pathway of caspase3. Plk1 gene play a key role in viability of MKN45 cells.