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Activation of Rac1 by Src-dependent phosphorylation of Dock180(Y1811) mediates PDGFR\ensuremath?-stimulated glioma tumorigenesis in mice and humans.

Feng, H, Hu, B, Liu, K-W, Li, Y, Lu, X, Cheng, T, Yiin, J-J, Lu, S, Keezer, S, Fenton, TR, and others. (2011) Activation of Rac1 by Src-dependent phosphorylation of Dock180(Y1811) mediates PDGFR\ensuremath?-stimulated glioma tumorigenesis in mice and humans. Journal of Clinical Investigation, 121 (12). pp. 4670-4684. ISSN 0021-9738. E-ISSN 1558-8238. (doi:10.1172/JCI58559) (KAR id:61516)

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Abstract

Two hallmarks of glioblastoma multiforme, the most common malignant brain cancer in humans, are aggressive growth and the ability of single glioma cells to disperse throughout the brain. These characteristics render tumors resistant to current therapies and account for the poor prognosis of patients. Although it is known that oncogenic signaling caused by overexpression of genes such as PDGFRA is responsible for robust glioma growth and cell infiltration, the mechanisms underlying glioblastoma malignancy remain largely elusive. Here, we report that PDGFR\ensuremath? signaling in glioblastomas leads to Src-dependent phosphorylation of the guanine nucleotide exchange factor Dock180 at tyrosine 1811 (Dock180(Y1811)) that results in activation of the GTPase Rac1 and subsequent cell growth and invasion. In human glioma cells, knockdown of Dock180 and reversion with an RNAi-resistant Dock180(Y1811F) abrogated, whereas an RNAi-resistant Dock180(WT) rescued, PDGFR\ensuremath?-promoted glioma growth, survival, and invasion. Phosphorylation of Dock180(Y1811) enhanced its association with CrkII and p130(Cas), causing activation of Rac1 and consequent cell motility. Dock180 also associated with PDGFR\ensuremath? to promote cell migration. Finally, phosphorylated Dock180(Y1811) was detected in clinical samples of gliomas and various types of human cancers, and coexpression of phosphorylated Dock180(Y1811), phosphorylated Src(Y418), and PDGFR\ensuremath? was predictive of extremely poor prognosis of patients with gliomas. Taken together, our findings provide insight into PDGFR\ensuremath?-stimulated gliomagenesis and suggest that phosphorylated Dock180(Y1811) contributes to activation of Rac1 in human cancers with PDGFRA amplification.

Item Type: Article
DOI/Identification number: 10.1172/JCI58559
Uncontrolled keywords: Animals, Brain Neoplasms, Cell Line, Tumor, Cell Movement, Enzyme Activation, Gene Amplification, Gene Expression Profiling, Glioblastoma, Humans, Mice, Neoplasm Invasiveness, Neoplasm Proteins, Phosphorylation, Prognosis, Protein Processing, Post-Translational, Proto-Oncogene Proteins c-crk, RNA Interference, Receptor, Platelet-Derived Growth Factor alpha, Recombinant Fusion Proteins, Transplantation, Heterologous, rac GTP-Binding Proteins, rac1 GTP-Binding Protein, src-Family Kinases
Divisions: Faculties > Sciences > School of Biosciences
Depositing User: Tim Fenton
Date Deposited: 23 May 2017 17:10 UTC
Last Modified: 29 May 2019 18:59 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/61516 (The current URI for this page, for reference purposes)
Fenton, TR: https://orcid.org/0000-0002-4737-8233
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