title: Inhibition of hypoxia-induced gene transcription by substituted pyrazolyl oxadiazoles: initial lead generation and structure-activity relationships.
abstract: The transcription factors hypoxia-inducible factor-1 and -2 (HIF-1 and HIF-2) orchestrate a multitude of processes that allow tumor cells to survive under conditions of low oxygen and nutrients, and that lead to resistance to some apoptotic pathways and facilitate invasion and metastasis. Therefore, inhibition of transactivation by HIF has become an attractive target in cancer research. Herein we present the results of a cell-based screening approach that led to the discovery of substituted 1H-pyrazole-3-carboxamides. Chemical optimization of the hit class with respect to potency and metabolic stability is described; it resulted in novel 5-(1H-pyrazol-3-yl)-1,2,4-oxadiazoles that inhibit the hypoxia-induced accumulation of HIF-1α and HIF-2α. The HIF inhibitory potency in the screening cell system was improved from IC₅₀ 190 to 0.7 nM, and significant parts of the SAR are disclosed. For a key compound, the ability to suppress the hypoxia-induced expression of HIF target genes was studied in A549 human lung adenocarcinoma cells. The same compound shows a favorable pharmacokinetic profile in rats after i.v. and p.o. administration.
authors.affiliation: Department of Medicinal Chemistry, Bayer HealthCare Pharmaceuticals, Global Drug Discovery, Postfach 101709, 42096 Wuppertal (Germany). michael.haerter@bayer.com.
authors.forename: Michael
authors.initials: M
authors.lastname: Härter
authors.forename: Karl-Heinz
authors.initials: KH
authors.lastname: Thierauch
authors.forename: Stephen
authors.initials: S
authors.lastname: Boyer
authors.forename: Ajay
authors.initials: A
authors.lastname: Bhargava
authors.forename: Peter
authors.initials: P
authors.lastname: Ellinghaus
authors.forename: Hartmut
authors.initials: H
authors.lastname: Beck
authors.forename: Susanne
authors.initials: S
authors.lastname: Greschat-Schade
authors.forename: Holger
authors.initials: H
authors.lastname: Hess-Stumpp
authors.forename: Kerstin
authors.initials: K
authors.lastname: Unterschemmann
mesh_terms: D000284:Administration, Oral; D000577:Amides / Q000737:chemistry* / Q000493:pharmacokinetics / Q000633:toxicity; D000818:Animals; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D006207:Half-Life; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism; D007275:Injections, Intravenous; D010069:Oxadiazoles / Q000737:chemistry*; D011720:Pyrazoles / Q000737:chemistry*; D051381:Rats; D013329:Structure-Activity Relationship; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D000577:Amides; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D010069:Oxadiazoles; D011720:Pyrazoles; C031280:pyrazole
keywords: cancer; hit optimization; hypoxia-inducible factor (HIF); inhibitors; transcription factors