PT  - JOURNAL ARTICLE
AU  - Rapisarda, Annamaria
AU  - Uranchimeg, Badarch
AU  - Scudiero, Dominic A.
AU  - Selby, Mike
AU  - Sausville, Edward A.
AU  - Shoemaker, Robert H.
AU  - Melillo, Giovanni
TI  - Identification of Small Molecule Inhibitors of Hypoxia-inducible Factor 1 Transcriptional Activation Pathway
DP  - 2002 Aug 01
TA  - Cancer Research
PG  - 4316--4324
VI  - 62
IP  - 15
4099  - http://cancerres.aacrjournals.org/content/62/15/4316.short
4100  - http://cancerres.aacrjournals.org/content/62/15/4316.full
SO  - Cancer Res2002 Aug 01; 62
AB  - 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. ©2002 American Association for Cancer Research.