gms | German Medical Science

63rd Annual Meeting of the German Society of Neurosurgery (DGNC)
Joint Meeting with the Japanese Neurosurgical Society (JNS)

German Society of Neurosurgery (DGNC)

13 - 16 June 2012, Leipzig

HIF signalling in glioblastoma under the influence of carnosine

Meeting Abstract

  • H. Oppermann - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Leipzig
  • C. Renner - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Leipzig
  • J. Meixensberger - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Leipzig
  • F. Gaunitz - Klinik und Poliklinik für Neurochirurgie, Universitätsklinikum Leipzig

Deutsche Gesellschaft für Neurochirurgie. Japanische Gesellschaft für Neurochirurgie. 63. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Japanischen Gesellschaft für Neurochirurgie (JNS). Leipzig, 13.-16.06.2012. Düsseldorf: German Medical Science GMS Publishing House; 2012. DocFR.07.02

DOI: 10.3205/12dgnc215, URN: urn:nbn:de:0183-12dgnc2155

Published: June 4, 2012

© 2012 Oppermann et al.
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Outline

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Objective: Previous experiments indicated that the anti-neoplastic effect of carnosine on glioblastoma cells may be mediated by a modulation of HIF1 signalling. To further substantiate this hypothesis, we performed experiments with glioblastoma cell lines under hypoxia and treatment with carnosine.

Methods: HIF1 reporter genes with hypoxia-responsive elements controlling the secreted luciferase from Gaussia princeps were transfected into cells from the glioblastoma lines T98G, LN405, U87 and 1321N1 and into one primary culture. The cells were then cultured under hypoxic conditions (1% O2) without or with carnosine (50 mM). After 24 hours reporter gene activity was determined and mRNA was isolated. The mRNA was used for the quantification of HIF1 target genes by qRT-PCR. For the determination of cell viability and ATP production a cell based assay was employed.

Results: Reporter gene assays revealed a significant HIF activity under normoxic conditions in U87 cells and in the primary culture. Under hypoxic conditions enhanced activity was found in all lines aside from 1321N1. The primary culture did not respond with a further enhancement. Carnosine influenced reporter gene activity in a cell dependent manner with a strong enhancement in T98G and a strong reduction in U87 under hypoxia as well as under normoxia. qRT-PCR experiments revealed enhanced expression of VEGF, GAPDH and Glut1 mRNA under the influence of carnosine. Although an enhanced expression of GAPDH and Glut1 are supposed to result in enhanced glycolytic ATP production, all cells responded to carnosine with the described reduction in ATP.

Conclusions: Reporter gene experiments revealed that even under normoxic conditions some glioblastoma cells exhibit active HIF signalling. Carnosine influenced reporter gene activity in a cell dependent manner but induced the expression of HIF target genes in all lines. In conclusion, although carnosine positively influences the expression of HIF target genes the hypothesis that carnosine exhibits its anti-neoplastic effect by simply inhibiting HIF signalling appears to be too simplistic.