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.
Neuro Oncol
; 17(6): 832-42, 2015 Jun.
Article
em En
| MEDLINE
| ID: mdl-25468898
ABSTRACT
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.Palavras-chave
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MEDLINE
Assunto principal:
Neoplasias Encefálicas
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Proteínas Quinases Dependentes de AMP Cíclico
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Glioblastoma
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Proteínas rac de Ligação ao GTP
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Receptor alfa de Fator de Crescimento Derivado de Plaquetas
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article