title: Profiling environmental chemicals for activity in the antioxidant response element signaling pathway using a high throughput screening approach.
abstract: BACKGROUND
  Oxidative stress has been implicated in the pathogenesis of a variety of diseases ranging from cancer to neurodegeneration, highlighting the need to identify chemicals that can induce this effect. The antioxidant response element (ARE) signaling pathway plays an important role in the amelioration of oxidative stress. Thus, assays that detect the up-regulation of this pathway could be useful for identifying chemicals that induce oxidative stress.
  
  
  OBJECTIVE
  We used cell-based reporter methods and informatics tools to efficiently screen a large collection of environmental chemicals and identify compounds that induce oxidative stress.
  
  
  METHODS
  We utilized two cell-based ARE assay reporters, β-lactamase and luciferase, to screen a U.S. National Toxicology Program 1,408-compound library (NTP 1408, which contains 1,340 unique compounds) for their ability to induce oxidative stress in HepG2 cells using quantitative high throughput screening (qHTS).
  
  
  RESULTS
  Roughly 3% (34 of 1,340) of the unique compounds demonstrated activity across both cell-based assays. Based on biological activity and structure-activity relationship profiles, we selected 50 compounds for retesting in the two ARE assays and in an additional follow-up assay that employed a mutated ARE linked to β-lactamase. Using this strategy, we identified 30 compounds that demonstrated activity in the ARE-bla and ARE-luc assays and were able to determine structural features conferring compound activity across assays.
  
  
  CONCLUSIONS
  Our results support the robustness of using two different cell-based approaches for identifying compounds that induce ARE signaling. Together, these methods are useful for prioritizing chemicals for further in-depth mechanism-based toxicity testing.
authors.affiliation: NIH Chemical Genomics Center, National Institutes of Health, Department of Health and Human Services, Rockville, Maryland, USA.
authors.forename: Sunita J
authors.initials: SJ
authors.lastname: Shukla
authors.forename: Ruili
authors.initials: R
authors.lastname: Huang
authors.forename: Steven O
authors.initials: SO
authors.lastname: Simmons
authors.forename: Raymond R
authors.initials: RR
authors.lastname: Tice
authors.forename: Kristine L
authors.initials: KL
authors.lastname: Witt
authors.forename: Danielle
authors.initials: D
authors.lastname: Vanleer
authors.forename: Ram
authors.initials: R
authors.lastname: Ramabhadran
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Austin
authors.forename: Menghang
authors.initials: M
authors.lastname: Xia
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D002460:Cell Line; D004785:Environmental Pollutants / Q000494:pharmacology; D057166:High-Throughput Screening Assays; D006801:Humans; D015398:Signal Transduction; D013329:Structure-Activity Relationship
chemical_list: D000975:Antioxidants; D004785:Environmental Pollutants