Abstract
Ionizing radiation is one of the agents inducing activation of DNA repair, cell cycle arrest, apoptosis and cell death. Here we report evidence for an enhanced activity of DNA polymerase beta, one of the repair enzymes, concomitant to the activation of the pathway phosphatidylinositol-3-kinase/AKT-1 (PI-3-kinase/AKT-1), which delivers a survival signal in Friend erythroleukemia cells exposed to 15 Gy. Significantly, the preincubation of the cellls with PI-3-kinase inhibitors wortmannin and LY 294002, disactivating this pathway, sensitizes the cells to ionizing radiation by further reducing the rate of proliferation without substantial variations of the number of dead cells. Thus, we suggest a role for these enzymes in maintaining survival programs upon exposure to ionizing radiation and in giving to these cells a chance to recover from this stress.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Androstadienes / pharmacology
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Cell Survival / physiology
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Cell Survival / radiation effects
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Chromones / pharmacology
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DNA Repair / physiology
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Enzyme Activation / drug effects
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Enzyme Activation / physiology
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Enzyme Activation / radiation effects
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Enzyme Inhibitors / pharmacology
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Humans
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Leukemia, Erythroblastic, Acute
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Morpholines / pharmacology
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Phosphatidylinositol 3-Kinases / metabolism*
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Phosphoinositide-3 Kinase Inhibitors
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Protein Serine-Threonine Kinases / metabolism*
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Proto-Oncogene Proteins c-akt
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Proto-Oncogene Proteins*
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Radiation, Ionizing
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Signal Transduction / physiology
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Signal Transduction / radiation effects*
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Tumor Cells, Cultured
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Wortmannin
Substances
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Androstadienes
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Chromones
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Enzyme Inhibitors
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Morpholines
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Phosphoinositide-3 Kinase Inhibitors
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Proto-Oncogene Proteins
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2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
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AKT1 protein, human
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Protein Serine-Threonine Kinases
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Proto-Oncogene Proteins c-akt
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Wortmannin