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Hypoxia-inducible factor (HIF) plays an important role in determining patterns of gene expression in cancer. HIF is down-regulated in oxygenated cells by a series of Fe (II) and 2-oxoglutarate dependent dioxygenases that hydroxylate specific residues in the regulatory HIF-alpha subunits. Because these enzymes require ascorbate for activity in vitro we analyzed the effects of ascorbate on HIF in human cancer cell lines. Ascorbate at physiological concentrations (25 micro M) strikingly suppressed HIF-1alpha protein levels and HIF transcriptional targets, particularly when the system was oncogenically activated in normoxic cells. Similar results were obtained with iron supplementation. These results indicate that both ascorbate and iron availability have major effects on HIF, and imply that the system is commonly regulated by limiting hydroxylase activity under normoxic tissue culture conditions.


Journal article


Cancer research

Publication Date





1764 - 1768


Cancer Research United Kingdom Molecular Oncology Laboratory, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS.


Tumor Cells, Cultured, Humans, Neoplasms, Adenocarcinoma, Breast Neoplasms, Ovarian Neoplasms, Prostatic Neoplasms, Ferrous Compounds, Ascorbic Acid, Procollagen-Proline Dioxygenase, Intercellular Signaling Peptides and Proteins, Vascular Endothelial Growth Factors, Vascular Endothelial Growth Factor A, Endothelial Growth Factors, Transferrin, Monosaccharide Transport Proteins, Transcription Factors, RNA, Messenger, Lymphokines, Cell Hypoxia, Female, Male, Glucose Transporter Type 1, Hypoxia-Inducible Factor 1, alpha Subunit, Transcriptional Activation