title: Effect of 2-hydroxyethyl methacrylate on antioxidant responsive element-mediated transcription: a possible indication of its cytotoxicity.
abstract: BACKGROUND
  The resin monomer 2-hydroxyethyl methacrylate (HEMA) is known to be more cytotoxic than methyl methacrylate (MMA). Using a luciferase reporter assay system, we previously showed that MMA activates the glutathione S-transferase alpha 1 gene (Gsta1) promoter through the anti-oxidant responsive element (ARE). However, it is not known whether HEMA induces ARE-mediated transcription.
  
  
  RESULTS
  We further developed the reporter system and studied the concentration-dependent effect of HEMA on ARE enhancer activity. The revised system employed HepG2 cells stably transfected with a destabilized luciferase reporter vector carrying 2 copies of the 41-bp ARE region of Gsta1. In this system, MMA increased ARE activity by 244-fold at 30 mM; HEMA augmented ARE activity at 3 mM more intensely than MMA (36-fold versus 11-fold) and was equipotent as MMA at 10 mM (56-fold activation); however, HEMA failed to increase ARE activity at 30 mM. In HepG2 cells, HEMA detectably lowered the cellular glutathione levels at 10 mM and cell viability at 30 mM, but MMA did not.
  
  
  CONCLUSIONS
  These results suggest that the low-concentration effect of HEMA on ARE activity reflects its cytotoxicity. Our reporter system used to examine ARE activity may be useful for evaluating cytotoxicities of resin monomers at concentrations lower than those for which cell viabilities are reduced.
authors.affiliation: Department of Endodontics, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan. orimoto@dpc.agu.ac.jp
authors.forename: Ai
authors.initials: A
authors.lastname: Orimoto
authors.forename: Takahiro
authors.initials: T
authors.lastname: Suzuki
authors.forename: Atsuko
authors.initials: A
authors.lastname: Ueno
authors.forename: Tatsushi
authors.initials: T
authors.lastname: Kawai
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakamura
authors.forename: Takao
authors.initials: T
authors.lastname: Kanamori
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D002999:Clone Cells; D003603:Cytotoxins / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D017930:Genes, Reporter / Q000235:genetics; D005822:Genetic Vectors / Q000235:genetics; D005978:Glutathione / Q000378:metabolism; D056945:Hep G2 Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D000072019:Kelch-Like ECH-Associated Protein 1; D008156:Luciferases / Q000235:genetics; D008689:Methacrylates / Q000633:toxicity*; D008768:Methylmethacrylates / Q000633:toxicity; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D020218:Response Elements / Q000187:drug effects*; D014158:Transcription, Genetic / Q000187:drug effects*
chemical_list: D000975:Antioxidants; D003603:Cytotoxins; D047908:Intracellular Signaling Peptides and Proteins; C431364:KEAP1 protein, human; D000072019:Kelch-Like ECH-Associated Protein 1; D008689:Methacrylates; D008768:Methylmethacrylates; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; C005044:hydroxyethyl methacrylate; D008156:Luciferases; D005978:Glutathione