title: Effects of ethylene glycol monomethyl ether and its metabolite, 2-methoxyacetic acid, on organogenesis stage mouse limbs in vitro.
abstract: Exposure to ethylene glycol monomethyl ether (EGME), a glycol ether compound found in numerous industrial products, or to its active metabolite, 2-methoxyacetic acid (2-MAA), increases the incidence of developmental defects. Using an in vitro limb bud culture system, we tested the hypothesis that the effects of EGME on limb development are mediated by 2-MAA-induced alterations in acetylation programming. Murine gestation day 12 embryonic forelimbs were exposed to 3, 10, or 30 mM EGME or 2-MAA in culture for 6 days to examine effects on limb morphology; limbs were cultured for 1 to 24 hr to monitor effects on the acetylation of histones (H3K9 and H4K12), a nonhistone protein, p53 (p53K379), and markers for cell cycle arrest (p21) and apoptosis (cleaved caspase-3). EGME had little effect on limb morphology and no significant effects on the acetylation of histones or p53 or on biomarkers for cell cycle arrest or apoptosis. In contrast, 2-MAA exposure resulted in a significant concentration-dependent increase in limb abnormalities. 2-MAA induced the hyperacetylation of histones H3K9Ac and H4K12Ac at all concentrations tested (3, 10, and 30 mM). Exposure to 10 or 30 mM 2-MAA significantly increased acetylation of p53 at K379, p21 expression, and caspase-3 cleavage. Thus, 2-MAA, the proximate metabolite of EGME, disrupts limb development in vitro, modifies acetylation programming, and induces biomarkers of cell cycle arrest and apoptosis.
authors.affiliation: Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada.
authors.forename: Caroline
authors.initials: C
authors.lastname: Dayan
authors.forename: Barbara F
authors.initials: BF
authors.lastname: Hales
mesh_terms: D000085:Acetates / Q000008:administration & dosage / Q000633:toxicity*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D045744:Cell Line, Tumor; D005026:Ethylene Glycols / Q000008:administration & dosage / Q000633:toxicity*; D005121:Extremities / Q000254:growth & development*; D006657:Histones / Q000235:genetics / Q000378:metabolism; D051379:Mice; D038081:Organogenesis / Q000187:drug effects*; D012313:RNA / Q000235:genetics; D018675:Toxicity Tests
chemical_list: D000085:Acetates; D005026:Ethylene Glycols; D006657:Histones; D012313:RNA; C505409:Casp3 protein, mouse; D053148:Caspase 3; C005219:methyl cellosolve; C013598:methoxyacetic acid
keywords: histone deacetylase inhibition; lysine hyperacetylation; p53; teratogen