Abstract
Interferons are cytokines with potent antiviral and antiproliferative activities. We report that although a transient exposure to beta-interferon induces a reversible cell cycle arrest, a sustained treatment triggers a p53-dependent senescence program. Beta-interferon switched on p53 in two steps. First, it induced the acetylation of p53 at lysine 320 and its dephosphorylation at serine 392 but not p53 activity. Later on, it triggered a DNA signaling pathway, the phosphorylation of p53 at serine 15 and its transcriptional activity. In agreement, beta-interferon-treated cells accumulated gamma-H2AX foci and phosphorylated forms of ATM and CHK2. The DNA damage signaling pathway was activated by an increase in reactive oxygen species (ROS) induced by interferon and was inhibited by the antioxidant N-acetyl cysteine. More important, RNA interference against ATM inhibited p53 phosphorylation at serine 15, p53 activity and senescence in response to beta-interferon. Beta-interferon-induced senescence was more efficient in cells expressing either, p53, or constitutive allele of ERK2 or RasV12. Hence, beta-interferon-induced senescence targets preferentially cells with premalignant changes.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Acetylation
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Ataxia Telangiectasia Mutated Proteins
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Cell Cycle / drug effects*
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism
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Cellular Senescence*
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Checkpoint Kinase 2
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DNA Damage*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Fibroblasts / drug effects
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Fibroblasts / metabolism
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Histones / analysis
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Histones / metabolism
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Humans
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Interferon-beta / pharmacology*
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Lysine / metabolism
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Mitogen-Activated Protein Kinase 1 / metabolism
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Phosphorylation
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism
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RNA Interference
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Reactive Oxygen Species / metabolism
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Serine / metabolism
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Signal Transduction
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Transcription, Genetic
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Tumor Suppressor Protein p53 / genetics
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Tumor Suppressor Protein p53 / metabolism*
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Tumor Suppressor Proteins / genetics
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Tumor Suppressor Proteins / metabolism
Substances
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Cell Cycle Proteins
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DNA-Binding Proteins
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H2AX protein, human
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Histones
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Reactive Oxygen Species
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Tumor Suppressor Protein p53
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Tumor Suppressor Proteins
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Serine
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Interferon-beta
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Checkpoint Kinase 2
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ATM protein, human
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Ataxia Telangiectasia Mutated Proteins
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CHEK2 protein, human
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Protein Serine-Threonine Kinases
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Mitogen-Activated Protein Kinase 1
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Lysine