title: The role of the p53 protein in nitrosative stress-induced apoptosis of PC12 rat pheochromocytoma cells.
abstract: PC12 rat pheochromocytoma cells are widely used to investigate signaling pathways. The p143p53PC12 cell line expresses a Val143Ala mutant p53 protein that is less capable of binding to the p53 consensus site in DNA than its wild-type counterpart. Nitric oxide (NO), depending on its concentration, is able to activate several signal transduction pathways. We used sodium nitroprusside (SNP), an NO donor compound, to analyze NO-induced cellular stress in order to clarify the mechanism and role of nitrosative stress in pathological processes, including inflammation and cancer. SNP caused cell death when applied at a concentration of 400 μM, p143p53PC12 cells showing higher sensitivity than wild-type PC12 cells. The mechanisms leading to the increased SNP-sensitivity of p143p53PC12 cells were then investigated. The 400-μM SNP treatment caused stress kinase activation, phosphorylation of the eukaryotic initiation factor eIF2α and p53 protein, proteolytic activation of protein kinase R, caspase-9, and caspase-3, p53 stabilization, CHOP induction, cytochrome c release from mitochondria, and a decline in the level of the Bcl-2 protein in both cell lines. All these SNP-induced changes were more robust and/or permanent in cells with the mutant p53 protein. We thus conclude that (1) the main cause of the SNP-induced apoptosis of PC12 cells is the repression of the bcl-2 gene, evoked through p53 stabilization, stress kinase activation, and CHOP induction; (2) the higher SNP sensitivity of p143p53PC12 cells is the consequence of the stronger and earlier activation of the intrinsic apoptotic pathway.
authors: Department of Medical Biology, Medical School, University of Pécs, Szigeti út 12, H-7624, Pécs, Hungary.
authors: Judit
authors: J
authors: Varga
authors: Judit
authors: J
authors: Bátor
authors: Márton
authors: M
authors: Péter
authors: Zita
authors: Z
authors: Árvai
authors: Marianna
authors: M
authors: Pap
authors: György
authors: G
authors: Sétáló
authors: József
authors: J
authors: Szeberényi
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D017209:Apoptosis; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D053453:Caspase 9 / Q000235:genetics / Q000378:metabolism; D045304:Cytochromes c / Q000235:genetics / Q000378:metabolism; D015852:Eukaryotic Initiation Factor-2 / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D020125:Mutation, Missense; D009569:Nitric Oxide / Q000235:genetics / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D016716:PC12 Cells; D010766:Phosphorylation / Q000187:drug effects / Q000235:genetics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D051381:Rats; D013312:Stress, Physiological; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
chemical_list: D015852:Eukaryotic Initiation Factor-2; D020030:Nitric Oxide Donors; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D009599:Nitroprusside; D009569:Nitric Oxide; D045304:Cytochromes c; C505410:Casp3 protein, rat; C506435:Casp9 protein, rat; D053148:Caspase 3; D053453:Caspase 9