title: Identification of SCN3B as a novel p53-inducible proapoptotic gene.
abstract: Tumor suppressor p53 is a transcription factor that induces growth arrest and/or apoptosis in response to cellular stress. To identify novel p53-inducible genes, we compared the expression of genes in normal mouse embryo fibroblasts (MEFs) to p53-null cells by cDNA representational difference analysis. We report here that expression of endogenous sodium channel subunit beta 3 (SCN3B) is upregulated in mouse embryonic fibroblasts by DNA damage in a p53-dependent manner. In addition, we found that SCN3B levels are upregulated in human cancer cell lines by DNA damaging agents, as well as by overexpression of p53, but not significantly by p63 or p73. Furthermore, we identified two putative p53-binding sites upstream of the first exon (RE1) and in the third intron (RE2). The p53 protein can directly interact with the putative p53-binding sites in vivo, as assessed by chromatin immunoprecipitation. A reporter gene assay revealed that these two p53-binding sites are functional response elements. The SCN3B protein appears to be localized to the endoplasmic reticulum (ER). Introduction of the SCN3B gene into T98G and Saos2 cells potently suppressed colony formation. Furthermore, we found that adenovirus-mediated transfer of SCN3B induced apoptosis when combined with anticancer agents. The results presented here suggest that SCN3B mediates a p53-dependent apoptotic pathway and may be a candidate for gene therapy combined with anticancer drugs.
authors.affiliation: Department of Molecular Biology, Cancer Research Institute, Sapporo Medical University School of Medicine, S-1, W-17, Chuo-ku, Sapporo 060-8556, Japan.
authors.forename: Katsuya
authors.initials: K
authors.lastname: Adachi
authors.forename: Minoru
authors.initials: M
authors.lastname: Toyota
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Yamashita
authors.forename: Setsuko
authors.initials: S
authors.lastname: Ishida
authors.forename: Mutsumi
authors.initials: M
authors.lastname: Ohe-Toyota
authors.forename: Reo
authors.initials: R
authors.lastname: Maruyama
authors.forename: Yuji
authors.initials: Y
authors.lastname: Hinoda
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Saito
authors.forename: Kohzoh
authors.initials: K
authors.lastname: Imai
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Kudo
authors.forename: Takashi
authors.initials: T
authors.lastname: Tokino
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D001665:Binding Sites; D045744:Cell Line, Tumor; D005091:Exons / Q000235:genetics; D005347:Fibroblasts; D015316:Genetic Therapy; D006801:Humans; D007438:Introns / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D015222:Sodium Channels / Q000235:genetics* / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D062549:Voltage-Gated Sodium Channel beta-3 Subunit
chemical_list: C493324:SCN3B protein, human; C561426:SCN3B protein, mouse; D015222:Sodium Channels; D016159:Tumor Suppressor Protein p53; D062549:Voltage-Gated Sodium Channel beta-3 Subunit