Department of Integrative Oncology, British Columbia Cancer Research Centre, BC Cancer Agency, Vancouver, British Columbia, Canada.
Oncogene. 2013 Jan 3;32(1):50-60. doi: 10.1038/onc.2012.30. Epub 2012 Feb 6.
Epithelial-to-mesenchymal transition (EMT) causes fibrosis, cancer progression and metastasis. Integrin-linked kinase (ILK) is a focal adhesion adaptor and a serine/threonine protein kinase that regulates cell proliferation, survival and EMT. Elucidating the molecular mechanisms necessary for development and progression of human malignancies is critical to predict the most appropriate targets for cancer therapy. Here, we used transforming growth factor beta-1 (TGFβ-1) to promote EMT and migration in mammary epithelial cells. We demonstrate a requirement of ILK activity for TGFβ-1-mediated EMT in mammary epithelial cells. In addition to nuclear translocation of Snail and Slug, TGFβ-1 treatment also induced expression of the mammalian target of rapamycin complex 2 component Rictor and its phosphorylation on Thr1135. Interestingly, TGFβ-1 treatment also induced an interaction between ILK and Rictor. All of these TGFβ-1-induced processes were significantly suppressed by inhibiting ILK activity or by disrupting the ILK/Rictor complex using small-interfering RNA-mediated knockdown. Furthermore, we identified ILK/Rictor complex formation in cancer but not in normal cell types, and this was accompanied by ILK-dependent phosphorylation of Rictor on residue Thr1135. Inhibition of ILK partially reversed the basal mesenchymal phenotype of MDA-MB-231 cells and prevented EMT in MCF10A cells after TGFβ-1 treatment. These data demonstrate a requirement for ILK function in TGFβ-1-induced EMT in mammary epithelial cells and identify the ILK/Rictor complex as a potential molecular target for preventing/reversing EMT.
上皮间质转化（EMT）导致纤维化、癌症进展和转移。整合素连接激酶（ILK）是一种黏着斑衔接蛋白和丝氨酸/苏氨酸蛋白激酶，可调节细胞增殖、存活和 EMT。阐明人类恶性肿瘤发生和发展所需的分子机制对于预测癌症治疗的最合适靶点至关重要。在这里，我们使用转化生长因子β-1（TGFβ-1）促进乳腺上皮细胞的 EMT 和迁移。我们证明了 ILK 活性对于 TGFβ-1 介导的乳腺上皮细胞 EMT 的必要性。除了 Slug 和 Snail 的核易位外，TGFβ-1 处理还诱导了雷帕霉素复合物 2 成分 Rictor 的表达及其 Thr1135 上的磷酸化。有趣的是，TGFβ-1 处理还诱导了 ILK 和 Rictor 之间的相互作用。使用小干扰 RNA 介导的敲低抑制 ILK 活性或破坏 ILK/Rictor 复合物，可显著抑制所有这些 TGFβ-1 诱导的过程。此外，我们在癌症中但不在正常细胞类型中鉴定到了 ILK/Rictor 复合物的形成，并且伴随着 ILK 依赖性 Rictor Thr1135 残基的磷酸化。ILK 的抑制部分逆转了 MDA-MB-231 细胞的基础间充质表型，并防止了 TGFβ-1 处理后 MCF10A 细胞的 EMT。这些数据表明，ILK 功能在乳腺上皮细胞中 TGFβ-1 诱导的 EMT 中是必需的，并确定了 ILK/Rictor 复合物作为预防/逆转 EMT 的潜在分子靶点。
