title: Cytosine arabinoside rapidly activates Bax-dependent apoptosis and a delayed Bax-independent death pathway in sympathetic neurons.
abstract: Cytosine arabinoside (ara-C) is a nucleoside analog used in the treatment of hematologic malignancies. One of the major side effects of ara-C chemotherapy is neurotoxicity. In this study, we have further characterized the cell death induced by ara-C in sympathetic neurons. Similar to neurons undergoing trophic factor deprivation-induced apoptosis, ara-C-exposed neurons became hypometabolic before death and upregulated c-myb, c-fos, and Bim. Bax deletion delayed, but did not prevent, ara-C toxicity. Neurons died by apoptosis, indicated by the release of mitochondrial cytochrome-c and caspase-3 activation. p53-deficient neurons demonstrated decreased sensitivity to ara-C, but neither p53 nor multiple p53-regulated genes were induced. Mature neurons showed increased ara-C resistance. These results demonstrate that molecular mechanisms underlying ara-C-induced death are similar to those responsible for trophic factor deprivation-induced apoptosis. However, substantial differences in neuronal death after these two distinct stress stimuli exist since ara-C toxicity, unlike the developmental death, can proceed in the absence of Bax.
authors.affiliation: Departments of Neurology and Molecular Biology & Pharmacology, Washington University School of Medicine, Saint Louis, MO 63110, USA.
authors.forename: C G
authors.initials: CG
authors.lastname: Besirli
authors.forename: T L
authors.initials: TL
authors.lastname: Deckwerth
authors.forename: R J
authors.initials: RJ
authors.lastname: Crowder
authors.forename: R S
authors.initials: RS
authors.lastname: Freeman
authors.forename: E M
authors.initials: EM
authors.lastname: Johnson
mesh_terms: D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000633:toxicity*; D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002454:Cell Differentiation; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003561:Cytarabine / Q000633:toxicity*; D045304:Cytochromes c / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D017353:Gene Deletion; D016158:Genes, p53; D007700:Kinetics; D008297:Male; D051379:Mice; D008928:Mitochondria / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D019253:Proto-Oncogene Proteins c-bcl-2; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D017783:Superior Cervical Ganglion / Q000166:cytology*; D015854:Up-Regulation; D051028:bcl-2-Associated X Protein
chemical_list: D000964:Antimetabolites, Antineoplastic; C494827:Bax protein, mouse; C494828:Bax protein, rat; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D003561:Cytarabine; D045304:Cytochromes c; C505409:Casp3 protein, mouse; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases