gms | German Medical Science

62. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC)
Joint Meeting mit der Polnischen Gesellschaft für Neurochirurgen (PNCH)

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

07. - 11. Mai 2011, Hamburg

Gene regulation by short-term and long-term hypoxia in glioblastoma stem cell lines

Meeting Abstract

  • A. Kathagen - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Deutschland
  • A. Schulte - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Deutschland
  • H. Günther - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Deutschland
  • H. Phillips - Institut für Timorbiologie und Angiogenese, Genentech, Inc., South San Francisco, USA
  • M. Westphal - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Deutschland
  • K. Lamszus - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Deutschland

Deutsche Gesellschaft für Neurochirurgie. Polnische Gesellschaft für Neurochirurgen. 62. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Polnischen Gesellschaft für Neurochirurgen (PNCH). Hamburg, 07.-11.05.2011. Düsseldorf: German Medical Science GMS Publishing House; 2011. DocMO.07.02

DOI: 10.3205/11dgnc039, URN: urn:nbn:de:0183-11dgnc0394

Veröffentlicht: 28. April 2011

© 2011 Kathagen et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielfältigt, verbreitet und öffentlich zugänglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Objective: Tumor stem cells (TSC) are believed to be responsible for continuous glioma growth and progression. As severe hypoxia in distinct regions of tumors is one major hallmark of glioblastomas and a well-known factor involved in maintaining the TSC phenotype in glioblastomas, these regions may provide a niche where TSC escape conventional treatment. We aimed to identify genes regulated by short-term and long-term hypoxia in glioma stem cell (GS) lines and to assess their responsibilty for the maintenance of the TSC phenotype in glioblastomas.

Methods: GS cell lines were established from 4 different freshly resected glioblastomas either under normoxic conditions (21% O2, GSN lines) or in parallel under hypoxic conditions (1% O2, GSH lines), mimicking the conditions in human glioblastomas more closely. Subsequently, GSN lines were exposed to short-term hypoxia (48 hrs), and vice versa, GSH lines were exposed to short-term normoxia (48 hrs reoxygenation). Gene expression profiles for all conditions were determined using Affymetrix gene expression arrays. Validation of differentially expressed genes was performed on cell lines and tumor tissues using quantitative PCR, Western blot and immunohistochemical analyses.

Results: We identified distinct sets of genes induced by short-term hypoxia as opposed to long-term hypoxia. Transcriptional induction of selected genes was confirmed by real-time PCR analyses. Specifically, short-term hypoxia was responsible for a significant increase in gene expression of RORa (RAR-related orphan receptor alpha) by a mean factor of 2.21 in cell line GS-12, of ALDOC (aldolase C) by a mean factor of 1.6 in GS-11 and of 2.51 in GS-12, and of WSB1 by a mean factor of 3.64 in GS-11 and by 2.06 in GS-12 compared to normoxic controls. Time course experiments pointed towards a peak expression of all genes analyzed after 16 to 24 hrs. In addition, upregulation of these target genes was confirmed also at the protein level, and immunostaining of established tumor xenografts in nude mice, as well as of original human tumor tissue, identified characteristic localization patterns.

Conclusions: Distinct sets of genes are induced by short-term and long-term hypoxia in GS cells. The potential influence of these genes on the maintenance of the tumor stem cell phenotype warrants their evaluation as additional selective drug targets to eliminate TSC in glioblastomas.