Identification of small molecule inhibitors of hypoxia-inducible factor 1 transcriptional activation pathway

A Rapisarda, B Uranchimeg, DA Scudiero, M Selby… - Cancer research, 2002 - AACR
A Rapisarda, B Uranchimeg, DA Scudiero, M Selby, EA Sausville, RH Shoemaker, G Melillo
Cancer research, 2002AACR
Abstract Hypoxia-inducible factor 1 (HIF-1) is a master regulator of the transcriptional
response to oxygen deprivation. HIF-1 has been implicated in the regulation of genes
involved in angiogenesis [eg, vascular endothelial growth factor (VEGF) and inducible nitric
oxide synthase] and anaerobic metabolism (eg, glycolytic enzymes). HIF-1 is essential for
angiogenesis and is associated with tumor progression. In addition, overexpression of HIF-
1α has been demonstrated in many common human cancers. Therefore, HIF-1 is an …
Abstract
Hypoxia-inducible factor 1 (HIF-1) is a master regulator of the transcriptional response to oxygen deprivation. HIF-1 has been implicated in the regulation of genes involved in angiogenesis [e.g., vascular endothelial growth factor (VEGF) and inducible nitric oxide synthase] and anaerobic metabolism (e.g., glycolytic enzymes). HIF-1 is essential for angiogenesis and is associated with tumor progression. In addition, overexpression of HIF-1α has been demonstrated in many common human cancers. Therefore, HIF-1 is an attractive molecular target for development of novel cancer therapeutics. We have developed a cell-based high-throughput screen for the identification of small molecule inhibitors of the HIF-1 pathway. We have genetically engineered U251 human glioma cells to stably express a recombinant vector in which the luciferase reporter gene is under control of three copies of a canonical hypoxia-responsive element (U251-HRE). U251-HRE cells consistently expressed luciferase in a hypoxia- and HIF-1-dependent fashion. We now report the results of a pilot screen of the National Cancer Institute “Diversity Set,” a collection of approximately 2000 compounds selected to represent the greater chemical diversity of the National Cancer Institute chemical repository. We found four compounds that specifically inhibited HIF-1-dependent induction of luciferase but not luciferase expression driven by a constitutive promoter. In addition, these compounds inhibited hypoxic induction of VEGF mRNA and protein expression in U251 cells. Interestingly, three compounds are closely related camptothecin analogues and topoisomerase (Topo)-I inhibitors. We show that concomitant with HIF-1 and VEGF inhibition, the activity of the Topo-I inhibitors tested is associated with induction of cyclooxygenase 2 mRNA expression. The luciferase-based high-throughput screen is a feasible tool for the identification of small molecule inhibitors of HIF-1 transcriptional activation. In addition, our results suggest that altered Topo-I function may be associated with repression of HIF-1-dependent induction of gene expression.
AACR