title: Identification of NCF2/p67phox as a novel p53 target gene.
abstract: Analysis of microarrays performed in p53-, TAp63α- and ΔNp63α-inducible SaOs-2 cell lines allowed the identification of NCF2 mRNA upregulation in response to p53 induction. NCF2 gene encodes for p67phox, the cytosolic subunit of the NADPH oxidase enzyme complex. The recruitment of p67phox to the cell membrane causes the activation of the NADPH oxidase complex followed by the generation of NADP+ and superoxide from molecular oxygen. The presence of three putative p53 binding sites on the NCF2 promoter was predicted, and the subsequent luciferase and chromatin immunoprecipitation assays showed the activation of NCF2 promoter by p53 and its direct binding in vivo to at least one of the sites, thus confirming the hypothesis. NCF2 upregulation was also confirmed by real-time PCR in several cell lines after p53 activation. NCF2 knockdown by siRNA results in a significant reduction of ROS production and stimulates cell death, suggesting a protective function of Nox2-generated ROS in cells against apoptosis. These results provide insight into the redox-sensitive signaling mechanism that mediates cell survival involving p53 and its novel target NCF2/p67phox.
authors.affiliation: Department of Experimental Medicine and Surgery, University of Tor Vergata, Rome, Italy.
authors.forename: Dafne
authors.initials: D
authors.lastname: Italiano
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Lena
authors.forename: Gerry
authors.initials: G
authors.lastname: Melino
authors.forename: Eleonora
authors.initials: E
authors.lastname: Candi
mesh_terms: D002460:Cell Line; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D045325:HCT116 Cells; D006801:Humans; D019255:NADPH Oxidases / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D034741:RNA, Small Interfering; D060888:Real-Time Polymerase Chain Reaction; D013481:Superoxides / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
chemical_list: D010750:Phosphoproteins; D034741:RNA, Small Interfering; D016159:Tumor Suppressor Protein p53; C079789:neutrophil cytosol factor 67K; D013481:Superoxides; D019255:NADPH Oxidases