title: Editor's Highlight: Hydroxyurea Exposure Activates the P53 Signaling Pathway in Murine Organogenesis-Stage Embryos.
abstract: Hydroxyurea, an anticancer agent and potent teratogen, induces oxidative stress and activates a DNA damage response pathway in the gestation day (GD) 9 mouse embryo. To delineate the stress response pathways activated by this drug, we investigated the effect of hydroxyurea exposure on the transcriptome of GD 9 embryos. Timed pregnant CD-1 mice were treated with saline or hydroxyurea (400 mg/kg or 600 mg/kg) on GD 9; embryonic gene and protein expression were examined 3 h later. Microarray analysis revealed that the expression of 1346 probe sets changed significantly in embryos exposed to hydroxyurea compared with controls; the P53 signaling pathway was highly affected. In addition, P53 related family members, P63 and P73, were predicted to be activated and had common and unique downstream targets. Western blot analysis revealed that active phospho-P53 was significantly increased in drug-exposed embryos; confocal microscopy showed that the translocation of phospho-P53 to the nucleus was widespread in the embryo. Furthermore, qRT-PCR showed that the expression of P53-regulated genes (Cdkn1A, Fas, and Trp53inp1) was significantly upregulated in hydroxyurea-exposed embryos; the concentration of the redox sensitive P53INP1 protein was also increased in a hydroxyurea dose-dependent fashion. Thus, hydroxyurea elicits a significant effect on the transcriptome of the organogenesis stage murine embryo, activating several key developmental signaling pathways related to DNA damage and oxidative stress. We propose that the P53 pathway plays a central role in the embryonic stress response and the developmental outcome after teratogen exposure.
authors.affiliation: *Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, H3G 1Y6, Canada.
authors.forename: Nazem
authors.initials: N
authors.lastname: El Husseini
authors.affiliation: *Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, H3G 1Y6, Canada.
authors.forename: Ava E
authors.initials: AE
authors.lastname: Schlisser
authors.affiliation: *Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, H3G 1Y6, Canada barbara.hales@mcgill.ca.
authors.forename: Barbara F
authors.initials: BF
authors.lastname: Hales
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004622:Embryo, Mammalian / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D006918:Hydroxyurea / Q000633:toxicity*; D051379:Mice; D020411:Oligonucleotide Array Sequence Analysis; D038081:Organogenesis / Q000187:drug effects*; D011247:Pregnancy; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D016159:Tumor Suppressor Protein p53; D006918:Hydroxyurea
keywords: birth defects; developmental toxicity; embryonic stress; teratogen