Journal of Neuro-Oncology

, Volume 78, Issue 3, pp 233–247

Inhibition of hypoxia inducible factor-1α (HIF-1α) decreases vascular endothelial growth factor (VEGF) secretion and tumor growth in malignant gliomas

  • Randy L. Jensen
  • Brian T. Ragel
  • Kum Whang
  • David Gillespie
Laboratory Investigation

DOI: 10.1007/s11060-005-9103-z

Cite this article as:
Jensen, R.L., Ragel, B.T., Whang, K. et al. J Neurooncol (2006) 78: 233. doi:10.1007/s11060-005-9103-z

Summary

Introduction

Hypoxia inducible factor-1α (HIF-1α) regulates vascular endothelial growth factor (VEGF), the presumed principal mediator of angiogenesis in malignant gliomas, under normal physiologic conditions. We examined the effect of HIF-1α on VEGF secretion, tumor growth, and angiogenesis in malignant gliomas.

Methods

We examined 175 human gliomas for expression of HIF-1α and its downstream-regulated proteins. HIF-1α expression and VEGF secretion in glioma cell lines under normoxia and hypoxia were examined using␣ELISA and Western blot. Malignant glioma cell lines were transfected with dominant-negative HIF-1α (DN-HIF-1α) expression vector or siRNA constructs against the HIF-1α gene. Growth studies were conducted on cells with the highest VEGF/HIF-1α inhibition isolated from stable transfected cell lines. MIB-1-labeling index and microvascular density (MVD) measurements were performed on the in vivo tumors.

Results

HIF-1 expression correlates with malignant glioma phenotype and was not confined to perinecrotic, pseudopalisading cells. VEGF and HIF-1 expression was high in glioma cell lines even under normoxia, and increased after exposure to hypoxia or growth factor stimulation. Cells transfected with DN-HIF-1α or HIF-1α siRNA demonstrated decreased HIF-1α and VEGF secretion. In vivo but not in vitro growth decreased in response to VEGF and HIF-1 inhibition. HIF-1 siRNA studies showed decreased VEGF secretion and in vitro and in vivo growth of glioma cell lines. MVD was unchanged but MIB-1 proliferation index decreased for both types of HIF-1 inhibition.

Conclusions

VEGF and HIF-1α are elevated in malignant gliomas. HIF-1α inhibition results in VEGF secretion inhibition. HIF-1α expression affects glioma tumor growth, suggesting clinical applications for malignant glioma treatment.

Keywords

angiogenesisbrain tumorglioblastoma multiformehypoxia inducible factorsiRNAvascular endothelial growth factor

Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  • Randy L. Jensen
    • 1
    • 2
    • 4
  • Brian T. Ragel
    • 1
  • Kum Whang
    • 2
    • 3
  • David Gillespie
    • 1
    • 2
  1. 1.Department of NeurosurgeryUniversity of UtahSalt Lake CityUSA
  2. 2.Huntsman Cancer Institute,University of UtahSalt Lake CityUSA
  3. 3.Yonsei University, Wonju College of MedicineWonjuKorea
  4. 4.Department of NeurosurgeryUniversity of Utah Salt Lake CityUSA