A p53-independent role for the MDM2 antagonist Nutlin-3 in DNA damage response initiation
<p>Abstract</p> <p>Background</p> <p>The mammalian DNA-damage response (DDR) has evolved to protect genome stability and maximize cell survival following DNA-damage. One of the key regulators of the DDR is p53, itself tightly regulated by MDM2. Following double-strand D...
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| Format: | Article |
| Language: | English |
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BMC
2011-02-01
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| Series: | BMC Cancer |
| Online Access: | http://www.biomedcentral.com/1471-2407/11/79 |
| _version_ | 1818919582909333504 |
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| author | Kumar Sonia Valentine Jane M Moumen Abdeladim |
| author_facet | Kumar Sonia Valentine Jane M Moumen Abdeladim |
| author_sort | Kumar Sonia |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>The mammalian DNA-damage response (DDR) has evolved to protect genome stability and maximize cell survival following DNA-damage. One of the key regulators of the DDR is p53, itself tightly regulated by MDM2. Following double-strand DNA breaks (DSBs), mediators including ATM are recruited to the site of DNA-damage. Subsequent phosphorylation of p53 by ATM and ATM-induced CHK2 results in p53 stabilization, ultimately intensifying transcription of p53-responsive genes involved in DNA repair, cell-cycle checkpoint control and apoptosis.</p> <p>Methods</p> <p>In the current study, we investigated the stabilization and activation of p53 and associated DDR proteins in response to treatment of human colorectal cancer cells (HCT116<sup>p53+/+</sup>) with the MDM2 antagonist, Nutlin-3.</p> <p>Results</p> <p>Using immunoblotting, Nutlin-3 was observed to stabilize p53, and activate p53 target proteins. Unexpectedly, Nutlin-3 also mediated phosphorylation of p53 at key DNA-damage-specific serine residues (Ser15, 20 and 37). Furthermore, Nutlin-3 induced activation of CHK2 and ATM - proteins required for DNA-damage-dependent phosphorylation and activation of p53, and the phosphorylation of BRCA1 and H2AX - proteins known to be activated specifically in response to DNA damage. Indeed, using immunofluorescent labeling, Nutlin-3 was seen to induce formation of γH2AX foci, an early hallmark of the DDR. Moreover, Nutlin-3 induced phosphorylation of key DDR proteins, initiated cell cycle arrest and led to formation of γH2AX foci in cells lacking p53, whilst γH2AX foci were also noted in MDM2-deficient cells.</p> <p>Conclusion</p> <p>To our knowledge, this is the first solid evidence showing a secondary role for Nutlin-3 as a DDR triggering agent, independent of p53 status, and unrelated to its role as an MDM2 antagonist.</p> |
| first_indexed | 2024-12-20T01:08:09Z |
| format | Article |
| id | doaj.art-1ecaba6496294dceb9606a80da0ff495 |
| institution | Directory Open Access Journal |
| issn | 1471-2407 |
| language | English |
| last_indexed | 2024-12-20T01:08:09Z |
| publishDate | 2011-02-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Cancer |
| spelling | doaj.art-1ecaba6496294dceb9606a80da0ff4952022-12-21T19:58:45ZengBMCBMC Cancer1471-24072011-02-011117910.1186/1471-2407-11-79A p53-independent role for the MDM2 antagonist Nutlin-3 in DNA damage response initiationKumar SoniaValentine Jane MMoumen Abdeladim<p>Abstract</p> <p>Background</p> <p>The mammalian DNA-damage response (DDR) has evolved to protect genome stability and maximize cell survival following DNA-damage. One of the key regulators of the DDR is p53, itself tightly regulated by MDM2. Following double-strand DNA breaks (DSBs), mediators including ATM are recruited to the site of DNA-damage. Subsequent phosphorylation of p53 by ATM and ATM-induced CHK2 results in p53 stabilization, ultimately intensifying transcription of p53-responsive genes involved in DNA repair, cell-cycle checkpoint control and apoptosis.</p> <p>Methods</p> <p>In the current study, we investigated the stabilization and activation of p53 and associated DDR proteins in response to treatment of human colorectal cancer cells (HCT116<sup>p53+/+</sup>) with the MDM2 antagonist, Nutlin-3.</p> <p>Results</p> <p>Using immunoblotting, Nutlin-3 was observed to stabilize p53, and activate p53 target proteins. Unexpectedly, Nutlin-3 also mediated phosphorylation of p53 at key DNA-damage-specific serine residues (Ser15, 20 and 37). Furthermore, Nutlin-3 induced activation of CHK2 and ATM - proteins required for DNA-damage-dependent phosphorylation and activation of p53, and the phosphorylation of BRCA1 and H2AX - proteins known to be activated specifically in response to DNA damage. Indeed, using immunofluorescent labeling, Nutlin-3 was seen to induce formation of γH2AX foci, an early hallmark of the DDR. Moreover, Nutlin-3 induced phosphorylation of key DDR proteins, initiated cell cycle arrest and led to formation of γH2AX foci in cells lacking p53, whilst γH2AX foci were also noted in MDM2-deficient cells.</p> <p>Conclusion</p> <p>To our knowledge, this is the first solid evidence showing a secondary role for Nutlin-3 as a DDR triggering agent, independent of p53 status, and unrelated to its role as an MDM2 antagonist.</p>http://www.biomedcentral.com/1471-2407/11/79 |
| spellingShingle | Kumar Sonia Valentine Jane M Moumen Abdeladim A p53-independent role for the MDM2 antagonist Nutlin-3 in DNA damage response initiation BMC Cancer |
| title | A p53-independent role for the MDM2 antagonist Nutlin-3 in DNA damage response initiation |
| title_full | A p53-independent role for the MDM2 antagonist Nutlin-3 in DNA damage response initiation |
| title_fullStr | A p53-independent role for the MDM2 antagonist Nutlin-3 in DNA damage response initiation |
| title_full_unstemmed | A p53-independent role for the MDM2 antagonist Nutlin-3 in DNA damage response initiation |
| title_short | A p53-independent role for the MDM2 antagonist Nutlin-3 in DNA damage response initiation |
| title_sort | p53 independent role for the mdm2 antagonist nutlin 3 in dna damage response initiation |
| url | http://www.biomedcentral.com/1471-2407/11/79 |
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