title: Nitric oxide prevents UV-induced phosphorylation of the p53 tumor-suppressor protein at serine 46: a possible role in inhibition of apoptosis.
abstract: Ser-46 of p53 is phosphorylated in response to DNA-damage in vivo, and it plays a pivotal role for apoptotic signaling by p53 through regulating the transcriptional activation of genes involved in apoptosis. We found that the presence of the nitric oxide (NO) donor S-nitroso-N-acetyl-D,L-penicillamine (200-800 microM) during UV-irradiation of MCF-7 cells resulted in a significant reduction in the Ser-46 phosphorylation, compared to the UV-irradiated cells without NO. This reduction occurred independently of cyclic GMP generation and without affecting activities of p53 kinases such as the PI3K family, p38 MAPK, and HIPK2. The presence of NO was found to protect HCT116 human colon tumor cells containing wild-type p53 from UV-induced apoptosis, whereas no apparent inhibitory effect of NO on UV-induced apoptosis was observed in those deficient in p53. Our results suggest that NO-mediated protection of apoptosis is p53-dependent, occurring at least partly through NO-inhibition of phosphorylation of p53 on Ser-46.
authors.affiliation: International Agency for Research on Cancer, 150 Cours Albert Thomas, 69372 Lyon Cedex 08, France.
authors.forename: Rika
authors.initials: R
authors.lastname: Fukunaga-Takenaka
authors.forename: Kaoru
authors.initials: K
authors.lastname: Fukunaga
authors.forename: Masayuki
authors.initials: M
authors.lastname: Tatemichi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohshima
mesh_terms: D017209:Apoptosis; D002352:Carrier Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D015151:Immunoblotting; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D010069:Oxadiazoles / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D011233:Precipitin Tests; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011810:Quinoxalines / Q000494:pharmacology; D012694:Serine / Q000737:chemistry*; D015398:Signal Transduction; D013347:Subcellular Fractions / Q000378:metabolism; D013997:Time Factors; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D014466:Ultraviolet Rays; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D020928:Mitogen-Activated Protein Kinases; D009569:Nitric Oxide; D010069:Oxadiazoles; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011810:Quinoxalines; D012694:Serine; D016159:Tumor Suppressor Protein p53; D048051:p38 Mitogen-Activated Protein Kinases; C095284:1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one; C115114:HIPK2 protein, human