Abstract
Fibroblast growth factor-10 (FGF-10), an alveolar epithelial cell (AEC) mitogen that is critical for lung development, may promote AEC repair. We determined whether FGF-10 attenuates H2O2-induced, A549 and rat alveolar type II cell DNA damage. We show that FGF-10 prevents H2O2-induced DNA damage assessed by an alkaline elution, ethidium bromide fluorescence as well as by a comet assay. Mitogen-activated protein kinase inhibitors abolished the protective effect of FGF-10 against H2O2-induced DNA damage yet had no effect on H2O2-induced DNA damage. A Grb2-SOS inhibitor (SH3 binding peptide), an Ras inhibitor (farnesyl transferase inhibitor 277), and an Raf-1 inhibitor (forskolin) each prevented FGF-10- and H2O2-induced A549 cell ERK1/2 phosphorylation. Also, FGF-10 and H2O2 each induced negligible ERK1/2 phosphorylation in Ras dominant-negative (N17) cells. Inhibitors of Ras and Raf-1 blocked the protective effect of FGF-10 against H2O2-induced DNA damage but had no effect on H2O2-induced DNA damage. Furthermore, cold conditions and aphidicolin, an inhibitor of DNA polymerase-alpha, -delta, and -epsilon, each blocked the protective effects of FGF-10, suggesting a role for DNA repair. We conclude that FGF-10 attenuates H2O2-induced AEC DNA damage by mechanisms that involve activation of Grb2-SOS/Ras/RAF-1/ERK1/2 pathway and DNA repair.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Adaptor Proteins, Signal Transducing*
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Animals
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Cell Line
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DNA Damage / drug effects
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DNA Damage / genetics*
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DNA Repair / drug effects
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DNA Repair / genetics
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DNA-Directed DNA Polymerase / metabolism
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Enzyme Inhibitors / pharmacology
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Fibroblast Growth Factor 10
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Fibroblast Growth Factors / metabolism*
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Fibroblast Growth Factors / pharmacology
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GRB2 Adaptor Protein
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Humans
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Hydrogen Peroxide / antagonists & inhibitors
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Hydrogen Peroxide / toxicity
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MAP Kinase Signaling System / drug effects
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MAP Kinase Signaling System / physiology
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Mitogen-Activated Protein Kinase 3
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Mitogen-Activated Protein Kinases / drug effects
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Mitogen-Activated Protein Kinases / metabolism
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Nucleic Acid Synthesis Inhibitors
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Oxidants / antagonists & inhibitors
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Oxidants / toxicity
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Oxidative Stress / drug effects
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Oxidative Stress / genetics*
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Proteins / antagonists & inhibitors
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Proteins / metabolism
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Proto-Oncogene Proteins c-raf / antagonists & inhibitors
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Proto-Oncogene Proteins c-raf / metabolism
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Pulmonary Alveoli / drug effects
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Pulmonary Alveoli / metabolism*
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Pulmonary Alveoli / physiopathology
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Pulmonary Fibrosis / chemically induced
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Pulmonary Fibrosis / genetics
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Pulmonary Fibrosis / metabolism*
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Rats
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Respiratory Mucosa / drug effects
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Respiratory Mucosa / metabolism*
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ras Proteins / antagonists & inhibitors
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ras Proteins / metabolism
Substances
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Adaptor Proteins, Signal Transducing
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Enzyme Inhibitors
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FGF10 protein, human
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Fgf10 protein, rat
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Fibroblast Growth Factor 10
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GRB2 Adaptor Protein
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GRB2 protein, human
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Grb2 protein, rat
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Nucleic Acid Synthesis Inhibitors
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Oxidants
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Proteins
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Fibroblast Growth Factors
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Hydrogen Peroxide
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Proto-Oncogene Proteins c-raf
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Mitogen-Activated Protein Kinase 3
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Mitogen-Activated Protein Kinases
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DNA-Directed DNA Polymerase
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ras Proteins