The cell death response to the ROS inducer, cobalt chloride, in neuroblastoma cell lines according to p53 status

• Published in: International journal of oncology Vol. 39; no. 3; pp. 601 - 609
• Main Author: Ratinaud, Marie-Helene
• Format: Journal Article
• Language: English
• Published: Athens Editorial Academy of the International Journal of Oncology 01.09.2011; Spandidos Publications
• Subjects: Apoptosis; Apoptosis - drug effects; Apoptosis - genetics; Biological and medical sciences; Cell Line, Tumor; Cellular Biology; Cobalt; Cobalt - pharmacology; Gene Knockdown Techniques; Genes, p53; Humans; Life Sciences; Medical sciences; Mutation; Neuroblastoma; Neuroblastoma - drug therapy; Neuroblastoma - genetics; Neuroblastoma - metabolism; Neuroblastoma - pathology; Neurology; Reactive Oxygen Species; Reactive Oxygen Species - metabolism; RNA, Small Interfering; RNA, Small Interfering - administration & dosage; RNA, Small Interfering - genetics; Transfection; Tumor Suppressor Protein p53; Tumor Suppressor Protein p53 - genetics; Tumor Suppressor Protein p53 - metabolism; Tumors; Tumors of the nervous system. Phacomatoses; Oxidative stress; hypoxia mimetic; Nervous system diseases; Reactive oxygen species; Oxygen; Mimetic; Malignant tumor; Neuroblastoma; Autophagy; Cancerology; TP53 Gene; Cobalt chloride; Cell death; Established cell line; Hypoxia; Autonomic neuropathy; Cancer; Apoptosis; Tumor suppressor gene
• ISSN: 1019-6439; 1791-2423
• DOI: 10.3892/ijo.2011.1083

Cobalt chloride (CoCl2), a hypoxia-mimetic agent, induces reactive oxygen species (ROS) generation, leading to cell death. Divergent data have been reported concerning p53 implication in this apoptotic mechanism. In this study, we studied cobalt-induced cell death in neuroblastoma cell lines carrying wild-type (WT) p53 ( SHSY5Y) and a mutated DNA-binding domain p53 [SKNBE(2c)]. CoCl2 induced an upregulation of p53, p21 and PUMA expression in WT cells but not in SKNBE(2c). In SHSY5Y cells, p53 serine-15 phosphorylation appeared early (6 h) in the mitochondria, and also in the nucleus after 12 h. In contrast, in SKNBE(2c) cells, the slight nuclear signal disappeared with CoCl2 treatment. In SHSY5Y cells, a mitochondrial pathway dependent on caspases [collapse of mitochondrial transmembrane potential (∆Ψmt), caspase 3 and 9 activation], was activated in a time-dependent manner. SKNBE(2c) cells exhibited a delay in the cell death executive phase linked to a caspase-independent pathway, involving apoptosis inducing factor nuclear translocation, but also an autophagic process attested by LC3-II expression and cathepsin-B activation. The downregulation of p53 in SHSY5Y cells by siRNA induced a cell death pathway related to the one observed in SKNBE(2c) cells. Finally, CoCl2 induced time-dependent canonical p53 mitochondrial apoptosis in the WT p53 cell line, and caspase-independent cell death in cells with a mutated or KO p53.