Lin Sui-Wen, Ke Ferng-Chun, Hsiao Pei-Wen, Lee Ping-Ping, Lee Ming-Ting, Hwang Jiuan-Jiuan
Institute of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
Exp Cell Res. 2007 Feb 1;313(3):602-13. doi: 10.1016/j.yexcr.2006.11.003. Epub 2006 Nov 10.
The present study investigated the role of integrin-linked kinase (ILK) in TGFbeta1-stimulated invasion/migration of human ovarian cancer cells. We investigated TGFbeta1 regulation of ILK, and effects of ILK knockdown on TGFbeta1-stimulated invasion/migration and the associated proteinase systems, urokinase plasminogen activator (uPA) and matrix metalloproteinases (MMPs) in SKOV3 cells. TGFbeta1 stimulated ILK kinase activity, and had no effect on ILK protein/mRNA levels. Transient transfection of an ILK-specific siRNA (ILK-H) reduced ILK protein level, mRNA level and kinase activity. ILK knockdown by ILK-H suppressed the basal and TGFbeta1-stimulated invasion and migration. Further, ILK-H reduced the basal and TGFbeta1-stimulated secretion of uPA, and increased the secretion of its inhibitor (PAI-1). Conversely, ILK-H did not affect TGFbeta1-stimulated secretion of MMP2 and its cell-associated activator MT1-MMP. Additionally, TGFbeta1 activated Smad2 phosphorylation, and this was not affected by ILK knockdown. Earlier reports indicate that Smad2 activation increased the expression of MMP2 and MT1-MMP. Thus, TGFbeta1 may act through ILK-independent and Smad2-dependent signaling in regulating MMP2 and MT1-MMP in SKOV3 cells. Collectively, this study suggests that ILK serves as a key mediator in TGFbeta1 regulation of uPA/PAI-1 system critical for the invasiveness of human ovarian cancer cells. And ILK is a potential target for cancer therapy.
本研究调查了整合素连接激酶（ILK）在转化生长因子β1（TGFβ1）刺激的人卵巢癌细胞侵袭/迁移中的作用。我们研究了TGFβ1对ILK的调节作用，以及ILK基因敲低对TGFβ1刺激的SKOV3细胞侵袭/迁移及相关蛋白酶系统、尿激酶型纤溶酶原激活剂（uPA）和基质金属蛋白酶（MMPs）的影响。TGFβ1刺激ILK激酶活性，但对ILK蛋白/ mRNA水平无影响。瞬时转染ILK特异性小干扰RNA（ILK-H）可降低ILK蛋白水平、mRNA水平和激酶活性。ILK-H敲低ILK可抑制基础状态及TGFβ1刺激的侵袭和迁移。此外，ILK-H降低了基础状态及TGFβ1刺激的uPA分泌，并增加了其抑制剂（PAI-1）的分泌。相反，ILK-H不影响TGFβ1刺激的MMP2及其细胞相关激活剂MT1-MMP的分泌。另外，TGFβ1激活Smad2磷酸化，且这不受ILK基因敲低的影响。早期报道表明，Smad2激活可增加MMP2和MT1-MMP的表达。因此，在调节SKOV3细胞中的MMP2和MT1-MMP时，TGFβ1可能通过不依赖ILK和依赖Smad2的信号传导发挥作用。总的来说，本研究表明ILK是TGFβ1调节对人卵巢癌细胞侵袭至关重要的uPA/PAI-1系统的关键介质。并且ILK是癌症治疗的潜在靶点。
