title: Contribution of ATM and ATR kinase pathways to p53-mediated response in etoposide and methyl methanesulfonate induced DNA damage.
abstract: p53 is a key integrator of cellular response to DNA damage, supporting post-translational repair and driving transcription-mediated responses including cell cycle arrest, apoptosis, and repair. DNA damage sensing kinases recognize different types of DNA damage and initiate specific responses through various post-translational modifications of p53. This study evaluated chemical specificity of the p53 pathway response by manipulating p53 or its upstream kinases and assessing the effect on DNA damage and cellular responses to prototype chemicals: etoposide (ETP, topoisomerase II inhibitor) and methyl methane sulfonate (MMS, alkylating agent). p53-deficient cells demonstrated reduced accumulation of the p53 target proteins MDM2, p21, and Wip1; reduced apoptotic response; and increased DNA damage (p-H2AX and micronuclei) with both chemicals. However, p53 was not essential for cell cycle arrest in HT1080 or HCT116 cells. The two chemicals induced different patterns of kinase activation, particularly in terms of Chk 1, Chk 2, p38, and ERK 1/2. However, inhibition of the ATM pathway showed a greater effect on p53 activtation, apoptosis, and accumulation of DNA damage than ATR-Chk 1 or the MAP kinases regardless of the chemical used. These results indicate that ATM is the predominant upstream kinase responsible for activation of the p53-mediated DNA damage response for both MMS and ETP, though the downstream kinase response is markedly different. Environ. Mol. Mutagen. 58:72-83, 2017. © 2017 Wiley Periodicals, Inc.
authors.affiliation: The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina, 27709.
authors.forename: Bin
authors.initials: B
authors.lastname: Sun
authors.affiliation: ScitoVation, LLC, Research Triangle Park, NC, 27709.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Ross
authors.affiliation: ScitoVation, LLC, Research Triangle Park, NC, 27709.
authors.forename: Sean
authors.initials: S
authors.lastname: Rowley
authors.affiliation: Unilever, Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedfordshire, MK44 1LQ, United Kingdom.
authors.forename: Yeyejide
authors.initials: Y
authors.lastname: Adeleye
authors.affiliation: ScitoVation, LLC, Research Triangle Park, NC, 27709.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Clewell
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D064007:Ataxia Telangiectasia Mutated Proteins / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D005047:Etoposide / Q000633:toxicity*; D005434:Flow Cytometry; D055785:Gene Knockdown Techniques; D045325:HCT116 Cells; D006801:Humans; D008698:Mesylates / Q000633:toxicity*; D015162:Micronucleus Tests; D015398:Signal Transduction; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
chemical_list: D008698:Mesylates; D016159:Tumor Suppressor Protein p53; C045880:methanesulfonic acid; D005047:Etoposide; C576324:ATM protein, human; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins
keywords: HCT116; HT1080; genotoxicity; micronucleus; p53 pathway