title: Involvement of AMP-activated protein kinase in mediating pyrrolo-1,5-benzoxazepine-induced apoptosis in neuroblastoma cells.
abstract: Neuroblastoma, a paediatric malignancy of the sympathetic nervous system, accounts for 15 % of childhood cancer deaths. Despite advances in understanding the biology, it remains one of the most difficult paediatric cancers to treat partly due to the development of multidrug resistance. There is thus a compelling demand for new treatment strategies that can bypass resistance mechanisms. The pyrrolo-1,5-benzoxazepine (PBOX) compounds are a series of novel microtubule-targeting agents that potently induce apoptosis in various tumour models. We have previously reported that PBOX compounds induce apoptosis in drug sensitive and multidrug resistant neuroblastoma cells and synergistically enhance apoptosis induced by chemotherapeutics such as carboplatin. In this study we present further data concerning the molecular basis of PBOX-induced apoptosis in neuroblastoma. We demonstrate that PBOX-6 induced AMP-activated protein kinase (AMPK) activation and downstream acetyl-CoA carboxylase phosphorylation. Increased reactive oxygen species (ROS) appeared to serve as the upstream signal for AMPK activation as pretreatment of cells with the antioxidant N-acetylcysteine inhibited both AMPK activation and PBOX-induced apoptosis. Furthermore, activation of AMPK by PBOX-6 was found to inhibit mTOR complex 1 (mTORC1) signalling. Finally, we demonstrate the efficacy of PBOX-6 in an in vivo xenograft model of neuroblastoma. This study provides new insights into understanding the molecular and cellular mechanisms involved in PBOX-induced cell death in neuroblastoma and further supports their future use as novel anti-cancer agents for the treatment of neuroblastoma.
authors.affiliation: School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland. lennonje@tcd.ie.|The National Children's Research Centre, Crumlin, Dublin, Ireland. lennonje@tcd.ie.
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Lennon
authors.affiliation: European Research Centre for Drug Discovery & Development (NatSynDrugs), University of Siena, Siena, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Butini
authors.affiliation: European Research Centre for Drug Discovery & Development (NatSynDrugs), University of Siena, Siena, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Campiani
authors.affiliation: Our Lady's Children's Hospital, Crumlin, Dublin 12, Ireland.
authors.forename: Anne
authors.initials: A
authors.lastname: O'Meara
authors.affiliation: School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland.
authors.forename: D Clive
authors.initials: DC
authors.lastname: Williams
authors.affiliation: School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland.
authors.forename: Daniela M
authors.initials: DM
authors.lastname: Zisterer
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D000103:Acetyl-CoA Carboxylase / Q000378:metabolism; D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D016190:Carboplatin / Q000627:therapeutic use; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D000076222:Mechanistic Target of Rapamycin Complex 1 / Q000378:metabolism; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D064549:Myeloid Cell Leukemia Sequence 1 Protein / Q000378:metabolism; D009447:Neuroblastoma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D010077:Oxazepines / Q000494:pharmacology* / Q000627:therapeutic use; D010766:Phosphorylation / Q000187:drug effects; D011758:Pyrroles / Q000494:pharmacology* / Q000627:therapeutic use; D017382:Reactive Oxygen Species / Q000378:metabolism; D050257:Tubulin Modulators / Q000494:pharmacology* / Q000627:therapeutic use; D047368:Tumor Burden / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D000975:Antioxidants; C579095:MCL1 protein, human; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D010077:Oxazepines; D011758:Pyrroles; D017382:Reactive Oxygen Species; D050257:Tubulin Modulators; D016190:Carboplatin; D000076222:Mechanistic Target of Rapamycin Complex 1; D055372:AMP-Activated Protein Kinases; D000103:Acetyl-CoA Carboxylase; C418868:PBOX-6; D000111:Acetylcysteine
keywords: AMPK; Mcl-1; PBOX-6; mTOR