title: Effect of p53 tumor suppressor on nucleotide excision repair in human colon carcinoma cells treated with 4-nitroquinoline 1-oxide.
abstract: In probing the mechanism of nucleotide excision repair (NER) in response to 4-nitroquinoline 1-oxide (4NQO)-induced DNA damage, the effect of p53 tumor suppressor was investigated. The effect of p53 protein on the repair of damaged DNA was examined by comet assay. Expression of p53 and p21(Waf1/Cip1) proteins was measured by the Enzyme-linked immunosorbent assay (ELISA) and immunocytochemistry, respectively. Compared to RKO cells having the wild-type p53 gene, increased cytotoxicity by 4NQO was observed in RKOmp53 cells with a mutation in p53 protein. DNA single strand breaks (SSB), indicative of the DNA repair, were considerably increased in 4NQO-treated RKO cells. Also, the expression of p53 and p21 proteins was significantly increased in 4NQO-treated RKO cells. In RKOmp53 cells, no effect of 4NQO on p21 expression was observed. Our findings suggest that 4NQO-induced NER is p53-dependent and involves up-regulation of its downstream regulator, p21(Waf1/Cip1) proteins.
authors.affiliation: Toxicology Laboratory, Korea Institute of Science and Technology, and Korea University, Seoul.
authors.forename: Y R
authors.initials: YR
authors.lastname: Seo
authors.forename: S H
authors.initials: SH
authors.lastname: Lee
authors.forename: S S
authors.initials: SS
authors.lastname: Han
authors.forename: J C
authors.initials: JC
authors.lastname: Ryu
mesh_terms: D015112:4-Nitroquinoline-1-oxide; D002273:Carcinogens; D002277:Carcinoma / Q000188:drug therapy* / Q000378:metabolism; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D020552:Comet Assay; D004249:DNA Damage / Q000187:drug effects*; D004260:DNA Repair / Q000187:drug effects*; D004277:DNA, Single-Stranded / Q000187:drug effects* / Q000302:isolation & purification; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D016650:Fluorescein-5-isothiocyanate; D006801:Humans; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D002273:Carcinogens; D004277:DNA, Single-Stranded; D016159:Tumor Suppressor Protein p53; D015112:4-Nitroquinoline-1-oxide; D016650:Fluorescein-5-isothiocyanate