TY - JOUR
T1 - Irradiation-Induced Regulation of Plasminogen Activator Inhibitor Type-1 and Vascular Endothelial Growth Factor in Six Human Squamous Cell Carcinoma Lines of the Head and Neck
AU - Artman, Tuuli
AU - Schilling, Daniela
AU - Gnann, Julia
AU - Molls, Michael
AU - Multhoff, Gabriele
AU - Bayer, Christine
N1 - Funding Information:
This study was supported in part by grants of the Technische Universität Munich ( KKF: 15-06 ), the Deutsche Forschungsgemeinschaft ( Ba 3514/1-1, PAK124 and Mu 1238/7-2 ), the Bundesministerium für Bildung und Forschung ( 01EZ0826 ), EU STEMDIAGNOSTICS ( LSHB CT 2007 037703 ), EU CARDIORISK ( FP 21140 ) and the Otto-Hellmeier Foundation .
PY - 2010/2/1
Y1 - 2010/2/1
N2 - Purpose: It has been shown that plasminogen activator inhibitor type-1 (PAI-1) and vascular endothelial growth factor (VEGF) are involved in neo-angiogenesis. The aim of this study was to investigate the irradiation-induced regulation of PAI-1 and VEGF in squamous cell carcinomas of the head and neck (SCCHN) cell lines of varying radiation sensitivity. 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-β1 (TGF-β1), hypoxia-inducible factor-1α (HIF-1α), hypoxia-inducible factor-2α (HIF-2α), or both HIF-1α and HIF-2α 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-β1 significantly decreased VEGF secretion in radiation-sensitive XF354 cells, and downregulation of HIF-1α and HIF-2α 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-β1 and HIF-1α could be partly responsible for VEGF and PAI-1 upregulation after irradiation.
AB - Purpose: It has been shown that plasminogen activator inhibitor type-1 (PAI-1) and vascular endothelial growth factor (VEGF) are involved in neo-angiogenesis. The aim of this study was to investigate the irradiation-induced regulation of PAI-1 and VEGF in squamous cell carcinomas of the head and neck (SCCHN) cell lines of varying radiation sensitivity. 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-β1 (TGF-β1), hypoxia-inducible factor-1α (HIF-1α), hypoxia-inducible factor-2α (HIF-2α), or both HIF-1α and HIF-2α 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-β1 significantly decreased VEGF secretion in radiation-sensitive XF354 cells, and downregulation of HIF-1α and HIF-2α 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-β1 and HIF-1α could be partly responsible for VEGF and PAI-1 upregulation after irradiation.
KW - Hypoxia-inducible factor (HIF)
KW - Irradiation
KW - Plasminogen activator inhibitor type-1 (PAI-1)
KW - Squamous cell carcinoma of the head and neck (SCCHN)
KW - Transforming growth factor-β1 (TGF-β1)
KW - Vascular endothelial growth factor (VEGF)
UR - http://www.scopus.com/inward/record.url?scp=73649115987&partnerID=8YFLogxK
U2 - 10.1016/j.ijrobp.2009.08.035
DO - 10.1016/j.ijrobp.2009.08.035
M3 - Article
C2 - 20117293
AN - SCOPUS:73649115987
SN - 0360-3016
VL - 76
SP - 574
EP - 582
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 2
ER -