gms | German Medical Science

57th Annual Meeting of the German Society of Neurosurgery
Joint Meeting with the Japanese Neurosurgical Society

German Society of Neurosurgery (DGNC)

11 - 14 May, Essen

Hypoxia-inducible carbonic anhydrase IX enhances invasion of glioma cells in vitro

Die Hypoxie-induzierbare Carboanhydrase IX steigert das Invasionsverhalten von Gliomzellen in-vitro.

Meeting Abstract

  • corresponding author M.A. Proescholdt - Neurochirurgische Universitätsklinik, Klinikum der Universität Regensburg
  • C. Mayer - Neurochirurgische Universitätsklinik, Klinikum der Universität Regensburg
  • S. Huber - Neurochirurgische Universitätsklinik, Klinikum der Universität Regensburg
  • E.-M. Störr - Neurochirurgische Universitätsklinik, Klinikum der Universität Regensburg
  • E. Stanbridge - Department of Microbiology and Molecular Genetics, College of Medicine, University of California at Irvine, Irvine, California, USA
  • A. Brawanski - Neurochirurgische Universitätsklinik, Klinikum der Universität Regensburg

Deutsche Gesellschaft für Neurochirurgie. Japanische Gesellschaft für Neurochirurgie. 57. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), Joint Meeting mit der Japanischen Gesellschaft für Neurochirurgie. Essen, 11.-14.05.2006. Düsseldorf, Köln: German Medical Science; 2006. DocP 05.60

The electronic version of this article is the complete one and can be found online at:

Published: May 8, 2006

© 2006 Proescholdt et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Objective: Malignant gliomas display high glucose utilization rates and show increased lactate levels. Despite that, the intracellular pH is alkaline, whereas the extracellular pH is highly acidic. The membrane associated, hypoxia-inducible carbonic anhydrase (CA) IX may be involved in the maintenance of this intra – extracellular pH gradient. We hypothesized that CA IX may acidify the immediate extracellular milieu and create a microenvironment conductive to tumor invasion. We therefore induced CA IX expression by hypoxia in vitro and analyzed the invasive potential of the cells in the presence of a specific carbonic anhydrase inhibitor.

Methods: U251 glioblastoma cells were cultured in a Biocoat Matrigel invasion chamber purchased from Becton Dickinson. A matrigel - coated polycarbonate filter was situated between upper and the lower well plates The chambers were incubated in a humified 5% CO2 modular with either 0% or 21% oxygen for 6 and 12 hours. Expression of CA IX was demonstrated with Western blotting using antibodies specific for CA IX. Subsequently, cells were treated either with carrier or with acetazolamide at a concentration range between 40 nm and 40 mM. At the end of the incubation time, the cells that had penetrated the matrigel - coated filter were stained and counted visually. Percent invasion was corrected for proliferation and calculated accordingly.

Results: Western blot analysis confirmed a strong and long lasting induction of the CA IX protein expression. The invasion of glioma cells was significantly enhanced after hypoxic treatment (p=0.01). This invasive behavior was again strongly inhibited by the treatment with acetazolamide in a dose dependent fashion (p=0.002).

Conclusions: Our data suggest that CA IX may be functionally involved in glioma invasion by the acidification of the extracellular milieu and subsequent activation of proteases such as cathepsin B.