Abstract | PURPOSE: METHODS AND MATERIALS: Six cell lines derived from SCCHN were investigated in vitro. The colorimetric AlamarBlue assay was used to detect metabolic activity of cell lines during irradiation as a surrogate marker for radiation sensitivity. PAI-1 and VEGF secretion levels were measured by enzyme-linked immunosorbent assay 24, 48, and 72 h after irradiation with 0, 2, 6, and 10 Gy. The direct radioprotective effect of exogenous PAI-1 was measured using the clonogenic assay. For regulation studies, transforming growth factor-beta1 (TGF-beta1), hypoxia-inducible factor-1alpha (HIF-1alpha), hypoxia-inducible factor-2alpha (HIF-2alpha), or both HIF-1alpha and HIF-2alpha were downregulated using siRNA. RESULTS: Although baseline levels varied greatly, irradiation led to a comparable dose-dependent increase in PAI-1 and VEGF secretion in all six cell lines. Addition of exogenous stable PAI-1 to the low PAI-1-expressing cell lines, XF354 and FaDu, did not lead to a radioprotective effect. Downregulation of TGF-beta1 significantly decreased VEGF secretion in radiation-sensitive XF354 cells, and downregulation of HIF-1alpha and HIF-2alpha reduced PAI-1 and VEGF secretion in radiation-resistant SAS cells. CONCLUSIONS: Irradiation dose-dependently increased PAI-1 and VEGF secretion in all SCCHN cell lines tested regardless of their basal levels and radiation sensitivity. In addition, TGF-beta1 and HIF-1alpha could be partly responsible for VEGF and PAI-1 upregulation after irradiation.
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Authors | Tuuli Artman, Daniela Schilling, Julia Gnann, Michael Molls, Gabriele Multhoff, Christine Bayer |
Journal | International journal of radiation oncology, biology, physics
(Int J Radiat Oncol Biol Phys)
Vol. 76
Issue 2
Pg. 574-82
(Feb 01 2010)
ISSN: 1879-355X [Electronic] United States |
PMID | 20117293
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Copyright | Copyright 2010 Elsevier Inc. All rights reserved. |
Chemical References |
- Basic Helix-Loop-Helix Transcription Factors
- Hypoxia-Inducible Factor 1, alpha Subunit
- Plasminogen Activator Inhibitor 1
- RNA, Small Interfering
- Transforming Growth Factor beta1
- Vascular Endothelial Growth Factor A
- endothelial PAS domain-containing protein 1
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Topics |
- Basic Helix-Loop-Helix Transcription Factors
(metabolism)
- Carcinoma, Squamous Cell
(metabolism, radiotherapy)
- Cell Line, Tumor
- Cell Survival
- Colorimetry
(methods)
- Dose-Response Relationship, Radiation
- Down-Regulation
- Enzyme-Linked Immunosorbent Assay
(methods)
- Head and Neck Neoplasms
(metabolism, radiotherapy)
- Humans
- Hypoxia-Inducible Factor 1, alpha Subunit
(metabolism)
- Plasminogen Activator Inhibitor 1
(metabolism)
- RNA, Small Interfering
(metabolism)
- Radiation Tolerance
- Transforming Growth Factor beta1
(metabolism)
- Vascular Endothelial Growth Factor A
(metabolism)
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