中文摘要：

目的探讨丝氨酸／苏氨酸激酶15（serine／threonine kinase15，STK15）基因在胃癌细胞有丝分裂中的作用。方法应用RNA干扰技术（RNAi）抑制胃癌细胞株MKN45细胞STK15基因表达；real-time定量PCR及Western blot检测干扰前后STK15 mRNA及蛋白质表达的变化；倒置显微镜观察MKN45细胞形态的变化；流式细胞仪检测细胞周期的变化；MTT法检测细胞增殖速度的变化；免疫荧光结合激光共聚焦显微镜观察MKN45细胞微管及有丝分裂表型的改变。结果STK15基因沉默后。其mRNA及蛋白质表达明显下降，real-time PCR结果显示，转染后48h，STK15^-组STK15 mRNA水平较对照siRNA组的下降了89．54％；Western blot灰度比半定量检测显示，STK15蛋白水平较对照siRNA组降低了57．18％。较多MKN45细胞呈圆形改变并呈现G2期细胞的DNA含量，STK15^-组3个时间点的圆形细胞占18．95％，而对照siRNA组为8．34％，差异有统计学意义（P〈0．05）；流式细胞仪检测结果显示，STK15。组G2期DNA含量细胞平均值为26．13％，而对照siRNA组G2期DNA含量细胞平均值12．46％（P〈0．05）。细胞增殖速度减慢（P〈0．05）。细胞有丝分裂表型发生改变（P〈0．05）。结论STK15基因在MKN45细胞有丝分裂过程中可能起着关键作用，阻断其表达可导致MKN45细胞有丝分裂停滞。

英文摘要：

Objective To investigate the role of STK15 in regulating mitosis of gastric cancer cells （MKN45） by gene silencing through RNA interference mechanism. Methods RNA interference technique was used to inhibit STK15 expression in MKN45 cells. The expression levels of STK15 mRNA and protein were measured by real-time quantitative RT-PCR and Western blot respectively and cell morphological changes were investigated by reverse microscopy. In addition, cell cycle distribution and cellular proliferation were determined by flow-cytometry and MTT assay respectively. Finally, the mitotic phenotype of MKN45 cells was studied by immunofluorescence staining and confocal microscopy. Results Silencing of STK15 gene by RNA interference was confirmed by marked decrease of STK15 mRNA and protein levels in the treated MKN45 cells. This silencing correlated with rounding of the cells, decreasing of DNA content in G2 phase （ P 〈 0. 05 ） and a lowered proliferation index （ P 〈 0. 05 ）, along with alterations of mitotic phenotype of MKN45 （P 〈 0. 05）. Conclusion STK15 gene may play a key role in regulating cellular mitosis and its inhibition by RNA interference leading to mitosis arrest in MKN45 cells.