Format

Send to

Choose Destination
See comment in PubMed Commons below
Neuro Oncol. 2012 Apr;14(4):426-39. doi: 10.1093/neuonc/nos055. Epub 2012 Mar 6.

Expression of podoplanin in human astrocytic brain tumors is controlled by the PI3K-AKT-AP-1 signaling pathway and promoter methylation.

Author information

1
Divisions of Signal Transduction and Growth Control, DKFZ/ZMBH Alliance, Heidelberg, Germany. h.peterziel@dkfz.de

Abstract

Recently, we found strong overexpression of the mucin-type glycoprotein podoplanin (PDPN) in human astrocytic brain tumors, specifically in primary glioblastoma multiforme (GB). In the current study, we show an inverse correlation between PDPN expression and PTEN levels in primary human GB and glioma cell lines, and we report elevated PDPN protein levels in the subventricular zone of brain tissue sections of PTEN-deficient mice. In human glioma cells lacking functional PTEN, reintroduction of wild-type PTEN, inhibition of the PTEN downstream target protein kinase B/AKT, or interference with transcription factor AP-1 function resulted in efficient downregulation of PDPN expression. In addition, we observed hypoxia-dependent PDPN transcriptional control and demonstrated that PDPN expression is subject to negative transcriptional regulation by promoter methylation in human GB and in glioma cell lines. Treatment of PTEN-negative glioma cells with demethylating agents induced expression of PDPN. Together, our findings show that increased PDPN expression in human GB is caused by loss of PTEN function and activation of the PI3K-AKT-AP-1 signaling pathway, accompanied by epigenetic regulation of PDPN promoter activity. Silencing of PDPN expression leads to reduced proliferation and migration of glioma cells, suggesting a functional role of PDPN in glioma progression and malignancy. Thus, specific targeting of PDPN expression and/or function could be a promising strategy for the treatment of patients with primary GB.

PMID:
22394497
PMCID:
PMC3309862
DOI:
10.1093/neuonc/nos055
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Silverchair Information Systems Icon for PubMed Central
    Loading ...
    Support Center