The TrkAIII oncoprotein inhibits mitochondrial free radical ROS-induced death of SH-SY5Y neuroblastoma cells by augmenting SOD2 expression and activity at the mitochondria, within the context of a tumour stem cell-like phenotype

• Published in: PloS one 2014-04, Vol.9 (4), p.e94568
• Main Authors: Ruggeri, Pierdomenico, Farina, Antonietta R, Di Ianni, Natalia, Cappabianca, Lucia, Ragone, Marzia, Ianni, Giulia, Gulino, Alberto, Mackay, Andrew R
• Format: Article
• Language: English
• Subjects: Alternative splicing; Analysis; Apoptosis; Biology and Life Sciences; Cancer therapies; Carcinogenesis - drug effects; Cell cycle; Cell death; Cell Death - drug effects; Cell Differentiation - drug effects; Cell Line, Tumor; Cell Survival - drug effects; Death; Disease Progression; Drug Resistance, Neoplasm; Enzyme inhibitors; Free radicals; Gene expression; Gene Expression Regulation, Neoplastic - drug effects; Gene Knockdown Techniques; Growth factors; Humans; Hydrogen peroxide; Inhibitors; Kinases; Ligands; Medicine and Health Sciences; Metastasis; Mitochondria; Mitochondria - drug effects; Mitochondria - metabolism; Mitochondrial DNA; Mortality; Neoplastic Stem Cells - drug effects; Neoplastic Stem Cells - pathology; Nerve growth factor; Nervous system; Neuroblastoma; Neuroblastoma - pathology; Neuroblastoma cells; NF-kappa B - metabolism; Oncogene Proteins - antagonists & inhibitors; Oncogene Proteins - metabolism; Oncoproteins; Oxygen; Parameter estimation; Paraquat; Pathogenesis; Phenotype; Phosphorylation; Phosphotransferases (Alcohol Group Acceptor) - metabolism; Physiology; Protein Isoforms - antagonists & inhibitors; Protein Isoforms - metabolism; Protein Kinase Inhibitors - pharmacology; Protein-tyrosine kinase; Proteins; Reactive oxygen species; Reactive Oxygen Species - metabolism; Receptor, trkA - antagonists & inhibitors; Receptor, trkA - metabolism; Rotenone; Signal transduction; siRNA; Spheroids, Cellular - drug effects; Spheroids, Cellular - pathology; Stem cells; Superoxide dismutase; Superoxide Dismutase - deficiency; Superoxide Dismutase - genetics; TrkA protein; TrkA receptors; Tumors; Tyrosine
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0094568

The developmental and stress-regulated alternative TrkAIII splice variant of the NGF receptor TrkA is expressed by advanced stage human neuroblastomas (NBs), correlates with worse outcome in high TrkA expressing unfavourable tumours and exhibits oncogenic activity in NB models. In the present study, we report that constitutive TrkAIII expression in human SH-SY5Y NB cells inhibits Rotenone, Paraquat and LY83583-induced mitochondrial free radical reactive oxygen species (ROS)-mediated death by stimulating SOD2 expression, increasing mitochondrial SOD2 activity and attenuating mitochondrial free radical ROS production, in association with increased mitochondrial capacity to produce H2O2, within the context of a more tumour stem cell-like phenotype. This effect can be reversed by the specific TrkA tyrosine kinase inhibitor GW441756, by the multi-kinase TrkA inhibitors K252a, CEP-701 and Gö6976, which inhibit SOD2 expression, and by siRNA knockdown of SOD2 expression, which restores the sensitivity of TrkAIII expressing SH-SY5Y cells to Rotenone, Paraquat and LY83583-induced mitochondrial free radical ROS production and ROS-mediated death. The data implicate the novel TrkAIII/SOD2 axis in promoting NB resistance to mitochondrial free radical-mediated death and staminality, and suggest that the combined use of TrkAIII and/or SOD2 inhibitors together with agents that induce mitochondrial free radical ROS-mediated death could provide a therapeutic advantage that may also target the stem cell niche in high TrkA expressing unfavourable NB.