TY - JOUR
T1 - The aurora kinase A regulates GSK-3β in gastric cancer cells
AU - Dar, A. A.
AU - Belkhiri, A.
AU - El-Rifai, W.
N1 - Funding Information:
This study was supported by a pilot fund from the National Cancer Institute GI SPORE grant CA95103 and the Vanderbilt-Ingram Cancer Center support funds. The contents of this work are solely the responsibility of the authors and do not necessarily represent the official views of the National Cancer Institute or Vanderbilt University Medical Center.
PY - 2009/2/12
Y1 - 2009/2/12
N2 - Aurora kinase A (AURKA) is located at 20q13, a region that is frequently amplified in gastric cancer. In this study, we have investigated the role of AURKA in regulating glycogen synthase kinase (GSK)-3β and β-catenin/TCF complex in gastric cancer cells. Our results demonstrate a significant increase in the phosphorylation of GSK-3β at Ser 9 following the overexpression of AURKA in AGS cells. The immunoprecipitation with antibodies specific for AURKA and GSK-3β indicated that the two proteins coexist in the same protein complex. The recombinant human AURKA protein phosphorylated the GSK-3β protein at Ser 9 in a concentration-dependent manner, in vitro. The phosphorylation of β-catenin (Ser33/37/Thr41) by GSK-3β is known to target β-catenin towards degradation. In line with our findings, the increase in phospho-GSK-3β level was accompanied by a significant decrease in β-catenin phosphorylation (Ser33/37/Thr41) and accumulation of β-catenin protein. The knockdown of AURKA reversed the phosphorylation of GSK-3β and the β-catenin protein levels. The immunofluorescence analysis demonstrated colocalization of AURKA and GSK-3β proteins and a significant increase in the nuclear β-catenin levels in cells overexpressing AURKA. The β-catenin/TCF transcription activity was measured using the pTopFlash and its mutant pFopFlash luciferase reporter vectors. Indeed, AURKA overexpression led to a significant increase in the pTopFlash reporter activity, whereas kinase dead AURKA mutant (D274A) had no effect. Consistent with these findings, we detected a significant mRNA up-regulation of several direct targets of the β-catenin/TCF transcription complex (cyclin D1, c-MYC, c-MYC-binding protein, CLDN1, FGF18 and vascular endothelial growth factor), and a two-fold increase in the proliferation rate in AURKA overexpressing cells. We conclude that the AURKA/GSK-3β interaction is important in regulating β-catenin, underscoring a novel oncogenic potential for AURKA in gastric tumorigenesis.
AB - Aurora kinase A (AURKA) is located at 20q13, a region that is frequently amplified in gastric cancer. In this study, we have investigated the role of AURKA in regulating glycogen synthase kinase (GSK)-3β and β-catenin/TCF complex in gastric cancer cells. Our results demonstrate a significant increase in the phosphorylation of GSK-3β at Ser 9 following the overexpression of AURKA in AGS cells. The immunoprecipitation with antibodies specific for AURKA and GSK-3β indicated that the two proteins coexist in the same protein complex. The recombinant human AURKA protein phosphorylated the GSK-3β protein at Ser 9 in a concentration-dependent manner, in vitro. The phosphorylation of β-catenin (Ser33/37/Thr41) by GSK-3β is known to target β-catenin towards degradation. In line with our findings, the increase in phospho-GSK-3β level was accompanied by a significant decrease in β-catenin phosphorylation (Ser33/37/Thr41) and accumulation of β-catenin protein. The knockdown of AURKA reversed the phosphorylation of GSK-3β and the β-catenin protein levels. The immunofluorescence analysis demonstrated colocalization of AURKA and GSK-3β proteins and a significant increase in the nuclear β-catenin levels in cells overexpressing AURKA. The β-catenin/TCF transcription activity was measured using the pTopFlash and its mutant pFopFlash luciferase reporter vectors. Indeed, AURKA overexpression led to a significant increase in the pTopFlash reporter activity, whereas kinase dead AURKA mutant (D274A) had no effect. Consistent with these findings, we detected a significant mRNA up-regulation of several direct targets of the β-catenin/TCF transcription complex (cyclin D1, c-MYC, c-MYC-binding protein, CLDN1, FGF18 and vascular endothelial growth factor), and a two-fold increase in the proliferation rate in AURKA overexpressing cells. We conclude that the AURKA/GSK-3β interaction is important in regulating β-catenin, underscoring a novel oncogenic potential for AURKA in gastric tumorigenesis.
KW - AURKA
KW - GSK-3β
KW - Gastric cancer
KW - β-catenin
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U2 - 10.1038/onc.2008.434
DO - 10.1038/onc.2008.434
M3 - Article
C2 - 19060929
AN - SCOPUS:60149085428
VL - 28
SP - 866
EP - 875
JO - Oncogene
JF - Oncogene
SN - 0950-9232
IS - 6
ER -