Abstract
Despite extensive study, the mechanisms of cell fate choice upon p53 activation remain poorly understood. Using genome-wide shRNA screening, we recently identified the ATM kinase as synthetic lethal with Nutlin-3, an MDM2 inhibitor that leads to non-genotoxic p53 activation. Here, we demonstrate that while this synthetic lethal interaction relies upon components of both the intrinsic and extrinsic apoptotic pathways (e.g., BAX and BID), it is not due to significant ATM effects on the expression of p53 target genes. Instead, loss of ATM activity results in increased mitochondria and reactive oxygen species that drive apoptosis. Finally, we provide evidence that pharmacologic inhibition of ATM blocks autophagy in direct opposition to p53, which activates this process, and that inhibition of autophagy is sufficient to elicit an apoptotic response when combined with Nutlin-3.
Keywords:
ATM; Nutlin-3; ROS; apoptosis; autophagy; mitochondria; p53; reactive oxygen species.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Apoptosis / drug effects
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Ataxia Telangiectasia Mutated Proteins / antagonists & inhibitors
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Ataxia Telangiectasia Mutated Proteins / metabolism*
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Autophagy / drug effects
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BH3 Interacting Domain Death Agonist Protein / antagonists & inhibitors
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BH3 Interacting Domain Death Agonist Protein / genetics
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BH3 Interacting Domain Death Agonist Protein / metabolism
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Caspase 8 / chemistry
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Caspase 8 / genetics
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Caspase 8 / metabolism
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HCT116 Cells
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Heat-Shock Proteins / metabolism
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Humans
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Imidazoles / pharmacology
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Mitochondria / metabolism
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Mitochondrial Turnover* / drug effects
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Morpholines / toxicity
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Nuclear Proteins / metabolism
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Piperazines / pharmacology
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Proto-Oncogene Proteins c-bcl-2 / antagonists & inhibitors
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Proto-Oncogene Proteins c-bcl-2 / genetics
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Proto-Oncogene Proteins c-bcl-2 / metabolism
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Pyrones / toxicity
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RNA Interference
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RNA, Small Interfering / metabolism
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Reactive Oxygen Species / metabolism*
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Tumor Suppressor Protein p53 / metabolism*
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bcl-2-Associated X Protein / genetics
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bcl-2-Associated X Protein / metabolism
Substances
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2-morpholin-4-yl-6-thianthren-1-yl-pyran-4-one
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BH3 Interacting Domain Death Agonist Protein
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Heat-Shock Proteins
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Imidazoles
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Morpholines
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Nuclear Proteins
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PMAIP1 protein, human
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Piperazines
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Proto-Oncogene Proteins c-bcl-2
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Pyrones
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RNA, Small Interfering
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Reactive Oxygen Species
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SESN1 protein, human
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SESN2 protein, human
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Tumor Suppressor Protein p53
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bcl-2-Associated X Protein
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nutlin 3
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Ataxia Telangiectasia Mutated Proteins
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Caspase 8