Abstract
Up-regulation of vascular endothelial growth factor (VEGF) expression is a major event leading to neovascularization in malignant gliomas. Hypoxia is believed to be the crucial environmental stimulus for this up-regulation. To critically assess this hypothesis, we asked whether the mechanisms defined previously for hypoxia-induced VEGF expression in vitro are similarly involved and sufficient for up-regulation of VEGF gene expression in vivo, using a lacZ reporter gene under the control of VEGF regulatory sequences in an experimental glioma model. Inclusion of the binding site for hypoxia- inducible factor 1 (HIF 1) in the 5' regulatory sequences used in the hybrid gene produced weak β-galactosidase staining in a special tumor cell subtype, the so-called perinecrotic palisading (PNP) cells that flank necrotic regions within the tumor. Deletion of the HIF 1 binding site abolished reporter gene expression in the PNP cells, indicating that transcriptional activation of VEGF expression in gliomas is mediated by HIF 1. Inclusion of 3' untranslated sequences from the VEGF gene in the reporter constructs resulted in an increased β-galactosidase staining in the PNP cells, suggesting that mRNA stabilization also contributes to VEGF up-regulation in glioblastoma cells growing as solid tumors. Combination of the 5' flanking region including the HIF 1 site along with 3' untranslated sequences produced increased levels of β-galactosidase expression in PNP cells. EF 5 immunostaining for regions of low oxygen partial pressure covered the same PNP cells that were stained for β-galactosidase. Collectively, the data provide experimental evidence that VEGF gene expression is activated in a distinct tumor cell subpopulation, the perinecrotic palisading cells of gliomas, by two distinct hypoxia-driven regulatory mechanisms.
| Original language | English |
|---|---|
| Pages (from-to) | 3860-3864 |
| Number of pages | 5 |
| Journal | Cancer Research |
| Volume | 57 |
| Issue number | 17 |
| Publication status | Published - 1997 Sep 1 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Cancer Research
- Oncology
Cite this
Up-regulation of vascular endothelial growth factor expression in a rat glioma is conferred by two distinct hypoxia-driven mechanisms. / Damert, Annette; Machein, Marcia; Breier, Georg; Fujita, Masaki Q; Hanahan, Douglas; Risau, Werner; Plate, Karl H.
In: Cancer Research, Vol. 57, No. 17, 01.09.1997, p. 3860-3864.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Up-regulation of vascular endothelial growth factor expression in a rat glioma is conferred by two distinct hypoxia-driven mechanisms
AU - Damert, Annette
AU - Machein, Marcia
AU - Breier, Georg
AU - Fujita, Masaki Q
AU - Hanahan, Douglas
AU - Risau, Werner
AU - Plate, Karl H.
PY - 1997/9/1
Y1 - 1997/9/1
N2 - Up-regulation of vascular endothelial growth factor (VEGF) expression is a major event leading to neovascularization in malignant gliomas. Hypoxia is believed to be the crucial environmental stimulus for this up-regulation. To critically assess this hypothesis, we asked whether the mechanisms defined previously for hypoxia-induced VEGF expression in vitro are similarly involved and sufficient for up-regulation of VEGF gene expression in vivo, using a lacZ reporter gene under the control of VEGF regulatory sequences in an experimental glioma model. Inclusion of the binding site for hypoxia- inducible factor 1 (HIF 1) in the 5' regulatory sequences used in the hybrid gene produced weak β-galactosidase staining in a special tumor cell subtype, the so-called perinecrotic palisading (PNP) cells that flank necrotic regions within the tumor. Deletion of the HIF 1 binding site abolished reporter gene expression in the PNP cells, indicating that transcriptional activation of VEGF expression in gliomas is mediated by HIF 1. Inclusion of 3' untranslated sequences from the VEGF gene in the reporter constructs resulted in an increased β-galactosidase staining in the PNP cells, suggesting that mRNA stabilization also contributes to VEGF up-regulation in glioblastoma cells growing as solid tumors. Combination of the 5' flanking region including the HIF 1 site along with 3' untranslated sequences produced increased levels of β-galactosidase expression in PNP cells. EF 5 immunostaining for regions of low oxygen partial pressure covered the same PNP cells that were stained for β-galactosidase. Collectively, the data provide experimental evidence that VEGF gene expression is activated in a distinct tumor cell subpopulation, the perinecrotic palisading cells of gliomas, by two distinct hypoxia-driven regulatory mechanisms.
AB - Up-regulation of vascular endothelial growth factor (VEGF) expression is a major event leading to neovascularization in malignant gliomas. Hypoxia is believed to be the crucial environmental stimulus for this up-regulation. To critically assess this hypothesis, we asked whether the mechanisms defined previously for hypoxia-induced VEGF expression in vitro are similarly involved and sufficient for up-regulation of VEGF gene expression in vivo, using a lacZ reporter gene under the control of VEGF regulatory sequences in an experimental glioma model. Inclusion of the binding site for hypoxia- inducible factor 1 (HIF 1) in the 5' regulatory sequences used in the hybrid gene produced weak β-galactosidase staining in a special tumor cell subtype, the so-called perinecrotic palisading (PNP) cells that flank necrotic regions within the tumor. Deletion of the HIF 1 binding site abolished reporter gene expression in the PNP cells, indicating that transcriptional activation of VEGF expression in gliomas is mediated by HIF 1. Inclusion of 3' untranslated sequences from the VEGF gene in the reporter constructs resulted in an increased β-galactosidase staining in the PNP cells, suggesting that mRNA stabilization also contributes to VEGF up-regulation in glioblastoma cells growing as solid tumors. Combination of the 5' flanking region including the HIF 1 site along with 3' untranslated sequences produced increased levels of β-galactosidase expression in PNP cells. EF 5 immunostaining for regions of low oxygen partial pressure covered the same PNP cells that were stained for β-galactosidase. Collectively, the data provide experimental evidence that VEGF gene expression is activated in a distinct tumor cell subpopulation, the perinecrotic palisading cells of gliomas, by two distinct hypoxia-driven regulatory mechanisms.
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UR - http://www.scopus.com/inward/citedby.url?scp=0030806074&partnerID=8YFLogxK
M3 - Article
VL - 57
SP - 3860
EP - 3864
JO - Cancer Research
JF - Cancer Research
SN - 0008-5472
IS - 17
ER -