title: The antioxidant function of the p53 tumor suppressor.
abstract: It is widely accepted that the p53 tumor suppressor restricts abnormal cells by induction of growth arrest or by triggering apoptosis. Here we show that, in addition, p53 protects the genome from oxidation by reactive oxygen species (ROS), a major cause of DNA damage and genetic instability. In the absence of severe stresses, relatively low levels of p53 are sufficient for upregulation of several genes with antioxidant products, which is associated with a decrease in intracellular ROS. Downregulation of p53 results in excessive oxidation of DNA, increased mutation rate and karyotype instability, which are prevented by incubation with the antioxidant N-acetylcysteine (NAC). Dietary supplementation with NAC prevented frequent lymphomas characteristic of Trp53-knockout mice, and slowed the growth of lung cancer xenografts deficient in p53. Our results provide a new paradigm for a nonrestrictive tumor suppressor function of p53 and highlight the potential importance of antioxidants in the prophylaxis and treatment of cancer.
authors.affiliation: Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, Ohio 44195, USA.
authors.forename: Anna A
authors.initials: AA
authors.lastname: Sablina
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Budanov
authors.forename: Galina V
authors.initials: GV
authors.lastname: Ilyinskaya
authors.forename: Larissa S
authors.initials: LS
authors.lastname: Agapova
authors.forename: Julia E
authors.initials: JE
authors.lastname: Kravchenko
authors.forename: Peter M
authors.initials: PM
authors.lastname: Chumakov
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D015152:Blotting, Northern; D015153:Blotting, Western; D045744:Cell Line, Tumor; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D004249:DNA Damage; D017931:DNA Primers; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D005786:Gene Expression Regulation / Q000502:physiology*; D005822:Genetic Vectors; D042822:Genomic Instability / Q000187:drug effects; D006801:Humans; D007621:Karyotyping; D016086:Lentivirus; D051379:Mice; D008954:Models, Biological; D016296:Mutagenesis; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013154:Spleen / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21; D017931:DNA Primers; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D016159:Tumor Suppressor Protein p53; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine; D000111:Acetylcysteine