title: Stress via p53 pathway causes apoptosis by mitochondrial Noxa upregulation in doxorubicin-treated neuroblastoma cells.
abstract: In this study, we employed a panel of cell lines to determine whether p53-dependent cell death in neuroblastoma (NB) cells is caused by apoptotic cellular function, and we further studied the molecular mechanism of apoptosis induced via the p53-dependent pathway. We obtained evidence that a type of p53-dependent stress, doxorubicin (Doxo) administration, causes accumulation of p53 in the nucleus of NB cells and phosphorylation of several serine residues in both Doxo-sensitive and -resistant cell lines. Upregulation of p53-downstream molecules in cells and upregulation of Noxa in the mitochondrial fraction were observed only in Doxo-sensitive NB cells. Significance of Noxa in the Doxo-induced NB cell death was confirmed by Noxa-knockdown experiments. Mitochondrial dysfunction, including cytochrome-c release and membrane potential disregulation, occurred and resulted in the activation of the intrinsic caspase pathway. However, in the Doxo-resistant cells, the accumulation in the nucleus and phosphorylation of p53 did not induce p53-downstream p21(Cip1/Waf1) expression and the Noxa upregulation, resulting in the retention of the mitochondrial homeostasis. Taken together, these findings indicate that the p53 pathway seems to play a crucial role in NB cell death by Noxa regulation in mitochondria, and inhibition of the induction of p53-downstream effectors may regulate drug resistance of NB cells.
authors.affiliation: Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kurata
authors.forename: R
authors.initials: R
authors.lastname: Yanagisawa
authors.forename: M
authors.initials: M
authors.lastname: Ohira
authors.forename: M
authors.initials: M
authors.lastname: Kitagawa
authors.forename: A
authors.initials: A
authors.lastname: Nakagawara
authors.forename: T
authors.initials: T
authors.lastname: Kamijo
mesh_terms: D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D017209:Apoptosis / Q000235:genetics; D045744:Cell Line, Tumor; D004317:Doxorubicin / Q000494:pharmacology*; D006801:Humans; D008928:Mitochondria / Q000378:metabolism; D009447:Neuroblastoma / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000494:pharmacology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D000903:Antibiotics, Antineoplastic; C498702:PMAIP1 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D004317:Doxorubicin