中文摘要：

目的探讨敲低信号转导及转录活化因子3（STAT3）表达对人胶质瘤细胞系U251细胞功能的影响及相关作用机制。方法脂质体介导STAT3反义寡聚核苷酸转染人胶质瘤细胞系U251细胞，同时设无义序列组和空白对照组，48h后MTT检测STAT3反义核苷酸对U251细胞增殖的影响，流式细胞仪检测各组细胞周期、细胞凋亡的变化，Transwell实验检测各组细胞的侵袭能力，Westernblotting检测STAT3和磷酸化STAT3（pSTAT3）蛋白、尿激酶型纤溶酶原激活物受体（uPAR）、B细胞淋巴瘤／白血病-2相关x蛋白（Bax）、B细胞淋巴瘤／白血病．2（Bcl．2）的表达水平。结果与空白对照组、无义序列组比较，STAT3反义核苷酸组细胞的相对存活率降低，G1／G0期细胞比例、细胞凋亡增加。Transwell实验显示滤膜细胞数明显减少，STAT3、pSTAT3、uPAR和Bcl．2蛋白的表达降低、Bax蛋白表达增加，差异均有统计学意义（P〈0．05）。结论反义STAT3可能通过调节相关基因表达抑制U25l细胞侵袭能力并诱导其调亡，STAT3可作为胶质瘤基因治疗的有效靶点。

英文摘要：

Objective To investigate the role of signal transducer and activator of transcription 3 （STAT3） knockdown in regulating the invasion and apoptosis of glioma cells. Methods Liposome-mediated STAT3 antisense oligonucleotide was transfected into the U251 glioma cells; nonsense sequence group and blank control group were also established. The effect of STAT3 antisense oligonucleotide on the growth of U251 glioma cells was examined by MTT assay; the cell cycle and apoptosis were evaluated by flow cytometry; the cell migration was determined by Transwell invasion assay. Western blotting was employed to explore the protein expressions of STAT3 and pSTAT3, urokinase-type plasminogen activator receptor （uPAR）, Bax and Bcl-2 in glioma cells. Results As compared with the nonsense sequence group and blank control group, liposome-mediated STAT3 antisense oligonucleotide group had lower survival rate, inhibited cell proliferation and cells being arrested at G0/G1 phases; Transwell invasion assay indicated that STAT3 antisense oligonucleotide suppressed the invasion and promoted the apoptosis of U251 cells. The STAT3, pSTAT3, uPAR and Bcl-2 expression levels in the iposome-mediated STAT3 antisense oligonucleotide group were siguficantly decreased as compared with those in the nonsense sequence group and blank control group, while Bax level was obviously elevated （/〈0.05）. Conclusion STAT3 antisense oligonucleotide can inhibit the invasion and promote the apoptosis of U251 cells by regulating its downstream gene expression; STAT3 can be used as an effective target for glioma gene therapy.