Document Detail


PDGF essentially links TGF-beta signaling to nuclear beta-catenin accumulation in hepatocellular carcinoma progression.
MedLine Citation:
PMID:  17130832     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The cooperation of Ras - extracellular signal-regulated kinase/mitogen-activated protein kinase and transforming growth factor (TGF)-beta signaling provokes an epithelial to mesenchymal transition (EMT) of differentiated p19(ARF) null hepatocytes, which is accompanied by a shift in malignancy and gain of metastatic properties. Upon EMT, TGF-beta induces the secretion and autocrine regulation of platelet-derived growth factor (PDGF) by upregulation of PDGF-A and both PDGF receptors. Here, we demonstrate by loss-of-function analyses that PDGF provides adhesive and migratory properties in vitro as well as proliferative stimuli during tumor formation. PDGF signaling resulted in the activation of phosphatidylinositol-3 kinase, and furthermore associated with nuclear beta-catenin accumulation upon EMT. Hepatocytes expressing constitutively active beta-catenin or its negative regulator Axin were employed to study the impact of nuclear beta-catenin. Unexpectedly, active beta-catenin failed to accelerate proliferation during tumor formation, but in contrast, correlated with growth arrest. Nuclear localization of beta-catenin was accompanied by strong expression of the Cdk inhibitor p16(INK4A) and the concomitant induction of the beta-catenin target genes cyclin D1 and c-myc. In addition, active beta-catenin revealed protection of malignant hepatocytes against anoikis, which provides a prerequisite for the dissemination of carcinoma. From these data, we conclude that TGF-beta acts tumor progressive by induction of PDGF signaling and subsequent activation of beta-catenin, which endows a subpopulation of neoplastic hepatocytes with features of cancer stem cells..
Authors:
A N M Fischer; E Fuchs; M Mikula; H Huber; H Beug; W Mikulits
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-11-20
Journal Detail:
Title:  Oncogene     Volume:  26     ISSN:  0950-9232     ISO Abbreviation:  Oncogene     Publication Date:  2007 May 
Date Detail:
Created Date:  2007-05-17     Completed Date:  2007-06-18     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8711562     Medline TA:  Oncogene     Country:  England    
Other Details:
Languages:  eng     Pagination:  3395-405     Citation Subset:  IM    
Affiliation:
Department of Medicine I, Division: Institute of Cancer Research, Medical University of Vienna, Vienna, Austria.
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MeSH Terms
Descriptor/Qualifier:
Anoikis
Carcinoma, Hepatocellular / metabolism*,  pathology*
Cell Differentiation
Cell Line, Tumor
Cell Nucleus / metabolism*
Cell Proliferation
Disease Progression
Epithelial Cells / metabolism
Humans
Platelet-Derived Growth Factor / metabolism*
Signal Transduction*
Transforming Growth Factor beta / metabolism*
beta Catenin / metabolism*
Chemical
Reg. No./Substance:
0/Platelet-Derived Growth Factor; 0/Transforming Growth Factor beta; 0/beta Catenin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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