蛋白激酶A介导的Dock180丝氨酸残基1250的磷酸化对于血小板衍生生长因子受体α刺激的胶质瘤生长和侵袭至关重要。
Protein kinase A-dependent phosphorylation of Dock180 at serine residue 1250 is important for glioma growth and invasion stimulated by platelet derived-growth factor receptor α.
作者信息
Feng Haizhong, Li Yanxin, Yin Yuhua, Zhang Weiwei, Hou Yanli, Zhang Lei, Li Zuoqing, Xie Baoshu, Gao Wei-Qiang, Sarkaria Jann N, Raizer Jeffery J, James C David, Parsa Andrew T, Hu Bo, Cheng Shi-Yuan
机构信息
State Key Laboratory of Oncogenes and Related Genes, Renji-Med X Clinical Stem Cell Research Center, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China (H.F., W.Z., Y.H., L.Z., Z.L., W.-Q.G., S.-Y.C.); Department of Neurology, Northwestern Brain Tumor Institute, Center for Genetic Medicine, The Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois (H.F., J.J.R., B.H., S.-Y.C.); Key Laboratory of Pediatric Hematology and Oncology Ministry of Health, Pediatric Translational Medicine Institute, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiao Tong University, Shanghai, China (Y.L.); Department of Neurological Surgery (Y.Y., B.X.); Department of Radiotherapy, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China (Y.H.); Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota (J.N.S.); Department of Neurological Surgery, Northwestern Brain Tumor Institute, The Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois (C.D.J., A.T.P.).
出版信息
Neuro Oncol. 2015 Jun;17(6):832-42. doi: 10.1093/neuonc/nou323. Epub 2014 Dec 2.
BACKGROUND
Dedicator of cytokinesis 1 (Dock1 or Dock180), a bipartite guanine nucleotide exchange factor for Rac1, plays critical roles in receptor tyrosine kinase-stimulated cancer growth and invasion. Dock180 activity is required in cell migration cancer tumorigenesis promoted by platelet derived growth factor receptor (PDGFR) and epidermal growth factor receptor.
METHODS
To demonstrate whether PDGFRα promotes tumor malignant behavior through protein kinase A (PKA)-dependent serine phosphorylation of Dock180, we performed cell proliferation, viability, migration, immunoprecipitation, immunoblotting, colony formation, and in vivo tumorigenesis assays using established and short-term explant cultures of glioblastoma cell lines.
RESULTS
Stimulation of PDGFRα results in phosphorylation of Dock180 at serine residue 1250 (S1250), whereas PKA inhibitors H-89 and KT5720 oppose this phosphorylation. S1250 locates within the Rac1-binding Dock homology region 2 domain of Dock180, and its phosphorylation activates Rac1, p-Akt, and phosphorylated extracellular signal-regulated kinase 1/2, while promoting cell migration, in vitro. By expressing RNA interference (RNAi)-resistant wild-type Dock180, but not mutant Dock180 S1250L, we were able to rescue PDGFRα-associated signaling and biological activities in cultured glioblastoma multiforme (GBM) cells that had been treated with RNAi for suppression of endogenous Dock180. In addition, expression of the same RNAi-resistant Dock180 rescued an invasive phenotype of GBM cells following intracranial engraftment in immunocompromised mice.
CONCLUSION
These data describe an important mechanism by which PDGFRα promotes glioma malignant phenotypes through PKA-dependent serine phosphorylation of Dock180, and the data thereby support targeting the PDGFRα-PKA-Dock180-Rac1 axis for treating GBM with molecular profiles indicating PDGFRα signaling dependency.
背景
细胞分裂素特异性鸟嘌呤核苷酸交换因子1（Dock1或Dock180）作为Rac1的双组分鸟嘌呤核苷酸交换因子，在受体酪氨酸激酶刺激的癌症生长和侵袭过程中发挥关键作用。血小板衍生生长因子受体（PDGFR）和表皮生长因子受体促进的细胞迁移及癌症肿瘤发生过程中需要Dock180的活性。
方法
为了证明PDGFRα是否通过蛋白激酶A（PKA）依赖的Dock180丝氨酸磷酸化促进肿瘤恶性行为，我们使用已建立的和短期的胶质母细胞瘤细胞系外植体培养物进行了细胞增殖、活力、迁移、免疫沉淀、免疫印迹、集落形成和体内肿瘤发生试验。
结果
PDGFRα的刺激导致Dock180丝氨酸残基1250（S1250）处发生磷酸化，而PKA抑制剂H-89和KT5720可抑制这种磷酸化。S1250位于Dock180的Rac1结合Dock同源区域2结构域内，其磷酸化激活Rac1、p-Akt和磷酸化的细胞外信号调节激酶1/2，同时在体外促进细胞迁移。通过表达RNA干扰（RNAi）抗性野生型Dock180，而不是突变型Dock180 S1250L，我们能够挽救在经RNAi处理以抑制内源性Dock180的培养多形性胶质母细胞瘤（GBM）细胞中与PDGFRα相关的信号传导和生物学活性。此外，相同的RNAi抗性Dock180的表达挽救了免疫缺陷小鼠颅内植入后GBM细胞的侵袭表型。
结论
这些数据描述了一种重要机制，即PDGFRα通过PKA依赖的Dock180丝氨酸磷酸化促进胶质瘤恶性表型，因此这些数据支持靶向PDGFRα-PKA-Dock180-Rac1轴来治疗具有表明PDGFRα信号依赖性分子特征的GBM。
Zotero 插件