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Published on: June 26, 2020
DNA damage response to the Mdm2 inhibitor nutlin-3
Rajeev Verma1, Marc J Rigatti, Glenn S Belinsky
1Department of Molecular & Cell Biology U3125, University of Connecticut, Storrs, CT 06269, USA.
Biochemical Pharmacology
|October 1, 2009
Summary
Mdm2 inhibitors like Nutlin-3 activate p53, triggering DNA damage responses and potentially slowing DNA repair in colon cancer cells. This may suppress some DNA repair but increase breakage risk.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- Mdm2 inhibitors are promising cancer therapeutics by activating p53.
- The precise effects of pharmacologically induced p53 activation require further elucidation.
Purpose of the Study:
- To investigate the consequences of Mdm2 inhibitor-induced p53 activation on DNA damage response and repair in colon cancer cells.
- To explore the role of p53 and cell cycle checkpoints in mediating these responses.
Main Methods:
- Utilized azoxymethane-induced mouse colon cancer cells and HCT116 human colon cancer cells.
- Assessed DNA damage response via H2AX and p53 phosphorylation (Ser-15) and gamma H2AX foci.
- Quantified DNA double-strand breaks, micronuclei formation, and sensitivity to DNA-damaging agents.
- Investigated the role of p21 deletion in modulating the DNA damage response.
Main Results:
- Nutlin-3 induced a DNA damage response in mouse colon cancer cells, evidenced by H2AX and p53 phosphorylation.
- This response correlated with p53 stabilization and was enantiomer-specific and observed with another Mdm2 inhibitor (Caylin-1).
- Nutlin-3 treatment led to DNA double-strand breaks, micronuclei formation, and sensitized cells to topoisomerase II inhibitors, while p21 deletion enhanced the response in HCT116 cells.
Conclusions:
- p53 activation by Mdm2 inhibitors can slow double-stranded DNA repair, potentially suppressing illegitimate homologous recombination.
- This mechanism may increase the risk of clastogenic events, highlighting a complex role in cancer treatment.
- Cell cycle checkpoint abnormalities may contribute to the DNA damage response triggered by Mdm2 inhibitors.
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