TY - JOUR
T1 - Overexpression of human NOX1 complex induces genome instability in mammalian cells
AU - Chiera, Federica
AU - Meccia, Ettore
AU - Degan, Paolo
AU - Aquilina, Gabriele
AU - Pietraforte, Donatella
AU - Minetti, Maurizio
AU - Lambeth, David
AU - Bignami, Margherita
PY - 2008/2/1
Y1 - 2008/2/1
N2 - The production of reactive oxygen species (ROS) in mammalian cells is tightly regulated because of their potential to damage macromolecules, including DNA. To investigate possible links between high ROS levels, oxidative DNA damage, and genomic instability in mammalian cells, we established a novel model of chronic oxidative stress by coexpressing the NADPH oxidase human (h) NOX1 gene together with its cofactors NOXO1 and NOXA1. Transfectants of mismatch repair (MMR)-proficient HeLa cells or MMR-defective Msh2-/- mouse embryo fibroblasts overexpressing the hNOX1 complex displayed increased intracellular ROS levels. In one HeLa clone in which ROS were particularly elevated, reactive nitrogen species were also increased and nitrated proteins were identified with an anti-3-nitrotyrosine antibody. Overexpression of the hNOX1 complex increased the steady-state levels of DNA 8-oxo-7,8-dihydroguanine and caused a threefold increase in the HPRT mutation rate in HeLa cells. In contrast, additional oxidatively generated damage did not affect the constitutive mutator phenotype of the Msh2-/- fibroblasts. Because no significant changes in the expression of several DNA repair enzymes for oxidative DNA damage were identified, we suggest that chronic oxidative stress can saturate the cell's DNA repair capacity and cause significant genomic instability.
AB - The production of reactive oxygen species (ROS) in mammalian cells is tightly regulated because of their potential to damage macromolecules, including DNA. To investigate possible links between high ROS levels, oxidative DNA damage, and genomic instability in mammalian cells, we established a novel model of chronic oxidative stress by coexpressing the NADPH oxidase human (h) NOX1 gene together with its cofactors NOXO1 and NOXA1. Transfectants of mismatch repair (MMR)-proficient HeLa cells or MMR-defective Msh2-/- mouse embryo fibroblasts overexpressing the hNOX1 complex displayed increased intracellular ROS levels. In one HeLa clone in which ROS were particularly elevated, reactive nitrogen species were also increased and nitrated proteins were identified with an anti-3-nitrotyrosine antibody. Overexpression of the hNOX1 complex increased the steady-state levels of DNA 8-oxo-7,8-dihydroguanine and caused a threefold increase in the HPRT mutation rate in HeLa cells. In contrast, additional oxidatively generated damage did not affect the constitutive mutator phenotype of the Msh2-/- fibroblasts. Because no significant changes in the expression of several DNA repair enzymes for oxidative DNA damage were identified, we suggest that chronic oxidative stress can saturate the cell's DNA repair capacity and cause significant genomic instability.
KW - 8-OxoGua
KW - DNA repair
KW - Free radicals
KW - Genetic instability
KW - hNOX1
KW - Reactive oxygen species
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U2 - 10.1016/j.freeradbiomed.2007.09.018
DO - 10.1016/j.freeradbiomed.2007.09.018
M3 - Article
C2 - 17963706
AN - SCOPUS:38149054921
VL - 44
SP - 332
EP - 342
JO - Free Radical Biology and Medicine
JF - Free Radical Biology and Medicine
SN - 0891-5849
IS - 3
ER -