title: Methadone induces CAD degradation and AIF-mediated necrotic-like cell death in neuroblastoma cells.
abstract: Methadone (d,l-methadone hydrochloride) is a full-opioid agonist, originally developed as a substitution for heroin or other opiates abusers. Nowadays methadone is also being applied as long-lasting analgesics in cancer, and it is proposed as a promising agent for leukemia therapy. Previously, we have demonstrated that high concentrations of methadone (0.5mM) induced necrotic-like cell death in SH-SY5Y cells. The pathway involved is caspase-independent but involves impairment of mitochondrial ATP synthesis and mitochondrial cytochrome c release. However, the downstream mitochondrial pathways remained unclear. Here, we studied the participation of apoptosis inducing factor (AIF) in methadone-induced cell death. Methadone resulted in a translocation of AIF from mitochondria to the nucleus. Translocation was inhibited by cyclosporine A, but not by lack of Bax protein. Therefore the effect seems mediated by the formation of the mitochondrial transition pore, but is apparently independent of Bax. Furthermore, methadone-treated SH-SY5Y nuclei show characteristics that are typical for stage I nuclear condensation. Methadone did not induce degradation of DNA into oligonucleosomal fragments or into high molecular weight DNA fragments. Absence of DNA fragmentation coincided with a considerable decrease in the levels of the caspase-actived endonuclase DNase and its chaperone-inhibitor ICAD. In conclusion, our results provide mechanistic insights into the molecular mechanisms that underlie methadone-induced cell death. This knowledge may prove useful to develop novel strategies to prevent toxic side-effects of methadone thereby sustaining its use as therapeutical agent against tumors.
authors.affiliation: Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Albacete, Spain.
authors.forename: Sergio
authors.initials: S
authors.lastname: Perez-Alvarez
authors.forename: Victoria
authors.initials: V
authors.lastname: Iglesias-Guimarais
authors.forename: María E
authors.initials: ME
authors.lastname: Solesio
authors.forename: Raquel María
authors.initials: RM
authors.lastname: Melero-Fernandez de Mera
authors.forename: Víctor J
authors.initials: VJ
authors.lastname: Yuste
authors.forename: María F
authors.initials: MF
authors.lastname: Galindo
authors.forename: Joaquín
authors.initials: J
authors.lastname: Jordán
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D051033:Apoptosis Inducing Factor / Q000032:analysis / Q000378:metabolism*; D045744:Cell Line, Tumor; D006657:Histones / Q000378:metabolism; D006801:Humans; D008691:Methadone / Q000494:pharmacology*; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009336:Necrosis / Q000139:chemically induced*; D009447:Neuroblastoma / Q000188:drug therapy*; D021381:Protein Transport / Q000187:drug effects*; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D000701:Analgesics, Opioid; D051033:Apoptosis Inducing Factor; D006657:Histones; D008691:Methadone; D051028:bcl-2-Associated X Protein; C475961:gamma-H2AX protein, mouse