University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213-1863, USA.
Oncogene. 2012 May 24;31(21):2691-702. doi: 10.1038/onc.2011.436. Epub 2011 Sep 26.
Dynamin 2 (Dyn2), a large GTPase, is involved in receptor tyrosine kinase (RTK)-promoted cell migration. However, the molecular mechanisms by which Dyn2 regulates RTK-induced cell migration have not been established. Recently, we reported that tyrosine-protein phosphatase non-receptor type 11 (SHP-2) and phosphatidylinositol 3-kinase (PI3K) mediate platelet-derived growth factor receptor-α (PDGFRα)-promoted glioma tumor growth and invasion. Here, we show that Dyn2 is an effector downstream of the PDGFRα-PI3K/SHP-2 signaling in glioma cells. Depletion of endogenous Dyn2 by short hairpin RNAs (shRNAs) inhibited PDGFRα-stimulated phosphorylation of Akt, Erk1/2, Rac1 and Cdc42 activities, glioma cell migration and survival in vitro and tumor growth and invasion in the brains of mice. Dyn2 binds to SHP-2 and PI3K and colocalizes with PDGFRα at the invasive fronts in PDGF-A-stimulated glioma cells. Inhibition of SHP-2 by siRNA knockdown abrogated Dyn2 association with activated PDGFRα and PDGFRα activation of Rac1 and Cdc42, and glioma cell migration, thereby establishing a link between SHP-2 interaction with Dyn2 and the PDGFRα signaling. Furthermore, a dominant-negative SHP-2 C459S mutant inhibited PDGF-A-stimulated glioma cell migration, phosphorylation of Dyn2 and concomitantly blocked PDGFRα-induced Src activation. Inhibition of Src by Src inhibitors attenuated PDGF-A-stimulated phosphorylation of Akt and Dyn2 and glioma cell migration. Additionally, mutations of binding sites to PI3K, SHP-2 or Src of PDGFRα impaired PDGFRα-stimulated phosphorylation of Akt and Dyn2, and Dyn2 association with activated PDGFRα. Taken together, this study identifies Dyn2 as an effector that mediates PDGFRα-SHP-2-induced glioma tumor growth and invasion, suggesting that targeting the PDGFRα-SHP-2-Dyn2 pathway may be beneficial to patients with malignant glioblastomas.
动力蛋白 2（Dyn2）是一种大 GTPase，参与受体酪氨酸激酶（RTK）促进的细胞迁移。然而，Dyn2 调节 RTK 诱导的细胞迁移的分子机制尚未建立。最近，我们报道了酪氨酸蛋白磷酸酶非受体型 11（SHP-2）和磷脂酰肌醇 3-激酶（PI3K）介导血小板衍生生长因子受体-α（PDGFRα）促进的神经胶质瘤肿瘤生长和侵袭。在这里，我们表明 Dyn2 是神经胶质瘤细胞中 PDGFRα-PI3K/SHP-2 信号的下游效应物。短发夹 RNA（shRNA）耗尽内源性 Dyn2 抑制了 PDGFRα 刺激的 Akt、Erk1/2、Rac1 和 Cdc42 的磷酸化、体外神经胶质瘤细胞迁移和存活以及小鼠大脑中的肿瘤生长和侵袭。Dyn2 与 SHP-2 和 PI3K 结合，并与 PDGF-A 刺激的神经胶质瘤细胞中 PDGFRα 在侵袭前沿共定位。siRNA 敲低抑制 SHP-2 消除了 Dyn2 与激活的 PDGFRα 的结合以及 PDGFRα 对 Rac1 和 Cdc42 的激活和神经胶质瘤细胞迁移，从而在 SHP-2 与 Dyn2 的相互作用与 PDGFRα 信号之间建立了联系。此外，显性负性 SHP-2 C459S 突变体抑制 PDGF-A 刺激的神经胶质瘤细胞迁移、Dyn2 的磷酸化，并同时阻断 PDGFRα 诱导的Src 激活。Src 抑制剂抑制 PDGF-A 刺激的 Akt 和 Dyn2 的磷酸化和神经胶质瘤细胞迁移。此外，PDGFRα 中 PI3K、SHP-2 或 Src 的结合位点突变损害了 PDGFRα 刺激的 Akt 和 Dyn2 的磷酸化以及 Dyn2 与激活的 PDGFRα 的结合。总之，这项研究确定 Dyn2 是一种效应物，介导 PDGFRα-SHP-2 诱导的神经胶质瘤肿瘤生长和侵袭，表明靶向 PDGFRα-SHP-2-Dyn2 途径可能有益于患有恶性神经胶质瘤的患者。
