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Håkan Axelson

Håkan Axelson

Research team manager

Håkan Axelson

Induction of ID2 expression by hypoxia-inducible factor-1: ARole in dedifferentiation of hypoxic neuroblastoma cells.

Author

  • Tobias Löfstedt
  • Annika Jögi
  • Mikael Sigvardsson
  • Katarina Gradin
  • Lorenz Poellinger
  • Sven Påhlman
  • Håkan Axelson

Summary, in English

ID (inhibitor of differentiation/DNA binding) proteins, frequently deregulated in advanced human malignancies, can participate in multiple fundamental traits of cancer, such as block of differentiation, increased proliferation, tissue invasiveness, and angiogenesis. We have previously demonstrated that hypoxia decreases expression of neuronal marker genes in neuroblastoma, but induces genes expressed in the neural crest, such as ID2. Because of its involvement in normal neural crest development and its ability to inhibit proneuronal bHLH proteins, the hypoxic induction of ID2 was of particular interest. Here we report fast induction kinetics of ID2 expression in hypoxic neuroblastoma cells. The up-regulation of ID2 was abolished by addition of actinomycin D, implicating a hypoxia-driven transcriptional mechanism. Analyzing the ID2 promoter revealed several potential binding sites for hypoxia-inducible factors. Subsequent electrophoretic mobility shift and chromatin immunoprecipitation assays demonstrated two functional HIF-1 binding sites within ID2 gene regulatory sequences located at –725 and –1893 relative to the transcriptional initiation point. In transfection assays, DNA constructs of the ID2 promoter, including the functional HIF-1 binding sites, induced luciferase reporter activity in a HIF-1-specific manner. These observations demonstrate that ID2 is actively engaged by hypoxia and represents a novel HIF-1 target. Hypoxia-induced ID2 expression could play a significant role in the previously observed dedifferentiation of hypoxic neuroblastoma cells, which in a clinical setting could lead to less mature and more aggressive tumors.

Department/s

  • Department of Translational Medicine
  • Stem Cell Center

Publishing year

2004

Language

English

Pages

39223-39231

Publication/Series

Journal of Biological Chemistry

Volume

279

Issue

38

Document type

Journal article

Publisher

American Society for Biochemistry and Molecular Biology

Topic

  • Cell and Molecular Biology

Status

Published

ISBN/ISSN/Other

  • ISSN: 1083-351X