Reactive oxygen species regulate epidermal growth factor-induced vascular endothelial growth factor and hypoxia-inducible factor-1α expression through activation of …

LZ Liu, XW Hu, C Xia, J He, Q Zhou, X Shi… - Free Radical Biology …, 2006 - Elsevier
LZ Liu, XW Hu, C Xia, J He, Q Zhou, X Shi, J Fang, BH Jiang
Free Radical Biology and Medicine, 2006Elsevier
The epidermal growth factor (EGF) and EGF receptor (EGFR) family are often overexpressed
in various human cancers including ovarian cancer. While it is generally believed that
reactive oxygen species (ROS) are involved in the intracellular signaling events, the role of
ROS in EGF-induced angiogenesis and carcinogenesis remains to be elucidated. The
present study investigated the role of ROS in the regulation of AKT, p70S6K1, vascular
endothelial growth factor (VEGF), and hypoxia-inducible factor 1 (HIF-1) in ovarian cancer …
The epidermal growth factor (EGF) and EGF receptor (EGFR) family are often overexpressed in various human cancers including ovarian cancer. While it is generally believed that reactive oxygen species (ROS) are involved in the intracellular signaling events, the role of ROS in EGF-induced angiogenesis and carcinogenesis remains to be elucidated. The present study investigated the role of ROS in the regulation of AKT, p70S6K1, vascular endothelial growth factor (VEGF), and hypoxia-inducible factor 1 (HIF-1) in ovarian cancer cells. In this study, OVCAR-3 cells were treated with EGF and catalase, an H2O2 scavenger. EGF treatment increases H2O2 production, leading to activation of the AKT/p70S6K1 pathway, resulting in increased VEGF expression at the transcriptional level. The inhibition of H2O2 production by catalase abolished EGF-induced AKT and p70S6K1 activation, and VEGF expression through HIF-1α expression. Forced expression of p70S6K1 and HIF-1α reversed catalase- and rapamycin-inhibited VEGF transcriptional activation. We also showed that rapamycin, p70S6K1 inhibitor and catalase overexpression inhibited tumor angiogenesis. This study demonstrates a novel mechanism of EGF-induced VEGF and HIF-1α expression through production of H2O2 and activation of AKT and p70S6K1 in human ovarian cancer cells. This study also indicates that p70S6K1 and H2O2 are important in tumor angiogenesis. The results of the study could have an important implication in ovarian cancer therapy.
Elsevier