title: Identification of a novel small-molecule inhibitor of the hypoxia-inducible factor 1 pathway.
abstract: Hypoxia-inducible factor 1 (HIF-1) is the central mediator of cellular responses to low oxygen and has recently become an important therapeutic target for solid tumor therapy. Inhibition of HIF-1 is expected to result in the attenuation of hypoxia-inducible genes, which are vital to many aspects of tumor biology, including adaptative responses for survival under anaerobic conditions. To identify small molecules inhibiting the HIF-1 pathway, we did a biological screen on a 10,000-membered natural product-like combinatorial library. The compounds of the library, which share a 2,2-dimethylbenzopyran structural motif, were tested for their ability to inhibit the hypoxic activation of an alkaline phosphatase reporter gene under the control of hypoxia-responsive elements in human glioma cells. This effort led to the discovery of 103D5R, a novel small-molecule inhibitor of HIF-1alpha. 103D5R markedly decreased HIF-1alpha protein levels induced by hypoxia or cobaltous ions in a dose- and time-dependent manner, whereas minimally affecting global cellular protein expression levels, including that of control proteins such as HIF-1beta, IkappaBalpha, and beta-actin. The inhibitory activity of 103D5R against HIF-1alpha was clearly shown under normoxia and hypoxia in cells derived from different cancer types, including glioma, prostate, and breast cancers. This inhibition prevented the activation of HIF-1 target genes under hypoxia such as vascular endothelial growth factor (VEGF) and glucose transporter-1 (Glut-1). Investigations into the molecular mechanism showed that 103D5R strongly reduced HIF-1alpha protein synthesis, whereas HIF-1alpha mRNA levels and HIF-1alpha degradation were not affected. 103D5R inhibited the phosphorylation of Akt, Erk1/2, and stress-activated protein kinase/c-jun-NH(2)-kinase, without changing the total levels of these proteins. Further studies on the mechanism of action of 103D5R will likely provide new insights into its validity/applicability for the pharmacologic targeting of HIF-1alpha for therapeutic purposes.
authors.affiliation: Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA 30322, USA.
authors.forename: Chalet
authors.initials: C
authors.lastname: Tan
authors.forename: Rita G
authors.initials: RG
authors.lastname: de Noronha
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Roecker
authors.forename: Beata
authors.initials: B
authors.lastname: Pyrzynska
authors.forename: Fatima
authors.initials: F
authors.lastname: Khwaja
authors.forename: Zhaobin
authors.initials: Z
authors.lastname: Zhang
authors.forename: Huanchun
authors.initials: H
authors.lastname: Zhang
authors.forename: Quincy
authors.initials: Q
authors.lastname: Teng
authors.forename: Ainsley C
authors.initials: AC
authors.lastname: Nicholson
authors.forename: Paraskevi
authors.initials: P
authors.lastname: Giannakakou
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Olson
authors.forename: M Manuela
authors.initials: MM
authors.lastname: Pereira
authors.forename: K C
authors.initials: KC
authors.lastname: Nicolaou
authors.forename: Erwin G
authors.initials: EG
authors.lastname: Van Meir
mesh_terms: D001578:Benzopyrans / Q000494:pharmacology*; D001685:Biological Factors / Q000494:pharmacology; D001943:Breast Neoplasms / Q000188:drug therapy; D045744:Cell Line, Tumor; D020650:Combinatorial Chemistry Techniques; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005909:Glioblastoma / Q000188:drug therapy; D006801:Humans; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D008297:Male; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000188:drug therapy; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D014157:Transcription Factors / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics
chemical_list: C496879:103D5R; D001578:Benzopyrans; D001685:Biological Factors; D004268:DNA-Binding Proteins; C497442:HIF1A protein, human; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009687:Nuclear Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D042461:Vascular Endothelial Growth Factor A