Department of Cell Biology and Genetics, Chongqing Medical University, 1 Yixueyuan Road, Yuzhong District, Chongqing 400016, PR China.
Int J Biochem Cell Biol. 2011 Sep;43(9):1294-304. doi: 10.1016/j.biocel.2011.05.003. Epub 2011 May 11.
Integrin-linked kinase (ILK), an intracellular serine/threonine kinase, is implicated in cell growth and survival, cell-cycle progression, tumor angiogenesis, and cell apoptosis. Recent studies showed that the expression and activity of ILK increased significantly in many types of solid tumors. However, the exact molecular mechanism of ILK underlie tumor has not been fully ascertained. The purpose of our study was to determine whether knockdown of ILK would inhibit cell growth and induce apoptosis in bladder cancer cells using a plasmid vector based small interfering RNA (siRNA). The experiments showed that knockdown of ILK could remarkably inhibit cell proliferation and growth, regulate cell cycle and induce apoptosis of bladder cancer BIU-87 and EJ cells. We demonstrated that knockdown of ILK inhibited phosphorylation of downstream signaling targets protein kinase B/Akt, glycogen synthase kinase 3-beta (GSK-3β), and reduced expression of β-catenin in BIU-87 as well as EJ cells by Western blot and Immunofluorescence analysis. In addition, down-regulation of ILK also could increase expression of Ribonuclease inhibitor (RI), an important acidic cytoplasmic protein with many functions. BALB/C nude mice injected with the BIU-87 cells transfected ILK siRNA showed a significant inhibition of the tumor growth with lighter tumor weight, lower microvessels density and higher apoptosis rate than those in the other two control groups. In conclusion, these results suggest that ILK might be involved in the development of bladder cancer, and could be served as a novel potential therapy target for human bladder cancer. Our study may be of biological and clinical importance.
整合素连接激酶（ILK）是一种细胞内丝氨酸/苏氨酸激酶，它与细胞生长和存活、细胞周期进程、肿瘤血管生成和细胞凋亡有关。最近的研究表明，ILK 的表达和活性在许多类型的实体瘤中显著增加。然而，ILK 导致肿瘤的确切分子机制尚未完全确定。我们的研究目的是使用基于质粒载体的小干扰 RNA（siRNA）确定下调 ILK 是否会抑制膀胱癌细胞的生长并诱导其凋亡。实验表明，下调 ILK 可显著抑制膀胱癌 BIU-87 和 EJ 细胞的增殖和生长，调节细胞周期并诱导其凋亡。我们通过 Western blot 和免疫荧光分析证实，下调 ILK 可抑制下游信号靶蛋白激酶 B/Akt、糖原合成酶激酶 3-β（GSK-3β）的磷酸化，并降低 BIU-87 以及 EJ 细胞中β-连环蛋白的表达。此外，下调 ILK 还可以增加核糖核酸酶抑制剂（RI）的表达，RI 是一种具有多种功能的重要酸性细胞质蛋白。用转染了 ILK siRNA 的 BIU-87 细胞注射的 BALB/C 裸鼠显示出肿瘤生长显著抑制，肿瘤重量更轻，微血管密度更低，凋亡率更高，与其他两个对照组相比差异具有统计学意义。总之，这些结果表明 ILK 可能参与膀胱癌的发生发展，可能成为人类膀胱癌的一个新的潜在治疗靶点。我们的研究可能具有生物学和临床意义。
