title: Menadione and ethacrynic acid inhibit the hypoxia-inducible factor (HIF) pathway by disrupting HIF-1α interaction with p300.
abstract: Hypoxia is a general characteristic of most solid malignancies and intimately related to neoplastic diseases and cancer progression. Homeostatic response to hypoxia is primarily mediated by hypoxia inducible factor (HIF)-1α that elicits transcriptional activity through recruitment of the CREB binding protein (CBP)/p300 coactivator. Targeted blockade of HIF-1α binding to CBP/p300 would thus constitute a novel approach for cancer treatment by suppressing tumor angiogenesis and metastasis. Here, we identified inhibitors against the interaction between HIF-1α and p300 by a fluorescence polarization-based assay employing a fluorescently-labeled peptide containing the C-terminal activation domain of HIF-1α. Two small molecule inhibitors, menadione (MD) and ethacrynic acid (EA), were found to decrease expression of luciferase under the control of hypoxia-responsive elements in hypoxic cells as well as to efficiently block the interaction between the full-length HIF-1α and p300. While these compounds did not alter the expression level of HIF-1α, they down-regulated expression of a HIF-1α target vascular endothelial growth factor (VEGF) gene. Considering hypoxia-induced VEGF expression leading to highly aggressive tumor growth, MD and EA may provide new scaffolds for development of tumor therapeutic reagents as well as tools for a better understanding of HIF-1α-mediated hypoxic regulation.
authors.affiliation: Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology, Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea.
authors.forename: Yu-Ran
authors.initials: YR
authors.lastname: Na
authors.forename: Ki-Cheol
authors.initials: KC
authors.lastname: Han
authors.forename: Hyunsung
authors.initials: H
authors.lastname: Park
authors.forename: Eun Gyeong
authors.initials: EG
authors.lastname: Yang
mesh_terms: D001665:Binding Sites / Q000235:genetics; D015687:Cell Hypoxia; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D050881:E1A-Associated p300 Protein / Q000235:genetics / Q000378:metabolism*; D004976:Ethacrynic Acid / Q000737:chemistry / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D015151:Immunoblotting; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D015394:Molecular Structure; D011485:Protein Binding / Q000187:drug effects; D025941:Protein Interaction Mapping / Q000379:methods; D020218:Response Elements / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics; D024483:Vitamin K 3 / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D042461:Vascular Endothelial Growth Factor A; D024483:Vitamin K 3; D008156:Luciferases; D050881:E1A-Associated p300 Protein; C494360:EP300 protein, human; D004976:Ethacrynic Acid