caa a22 4500 463208641 CHVBK 20180405153133.0 cr unu---uuuuu 170326e20070401xx s 000 0 eng 10.1007/s10863-007-9076-z doi (NATIONALLICENCE)springer-10.1007/s10863-007-9076-z High Bcl-2/Bax ratio in Walker tumor cells protects mitochondria but does not prevent H2O2-induced apoptosis via calcineurin pathways [Elektronische Daten] [Karina Zecchin, Ana Seidinger, Marcos Chiaratti, Giovanna Degasperi, Flávio Meirelles, Roger Castilho, Aníbal Vercesi] It has been previously shown that Walker 256 tumor cells express a high content of the anti-apoptotic protein Bcl-2 which protects mitochondria against the damaging effects of Ca2+. In the present study, we analyze H2O2-induced apoptotic death in two different types of tumor cells: Walker 256 and SCC-25. Treatment with H2O2 (4mM) increased reactive oxygen species generation and the concentration of cytosolic free Ca2+. These alterations preceded apoptosis in both cell lines. In Walker cells, which show a high Bcl-2/Bax ratio, apoptosis was dependent on calcineurin activation and independent of changes in mitochondrial membrane potential (Δ < eqid1 > m), as well as cytochrome c release. In contrast, in SCC-25 cells, which show a lower Bcl-2/Bax ratio, apoptosis was preceded by a decrease in Δ < eqid2 > m, mitochondrial permeability transition, and cytochrome c release. Caspase-3 activation occurred in both cell lines. The data suggest that although the high Bcl-2/Bax ratio protected the mitochondria of Walker cells from oxidative stress, it was not sufficient to prevent apoptosis through calcineurin pathways. Springer Science+Business Media, LLC, 2007 Bcl-2/Bax ratio nationallicence Calcineurin nationallicence Calcium homeostasis nationallicence Oxidative stress nationallicence Apoptosis nationallicence Mitochondrial permeability transition nationallicence BA : bongkrekic acid nationallicence BAPTA : 1,2-bis(2-aminophenoxy) ethane N,N,N′,N′-tetraacetic acid nationallicence CCCP : carbonyl cyanide m-chloro phenyl hydrazone nationallicence [Ca2+]cyt : cytosolic free calcium concentration nationallicence CsA : cyclosporin A nationallicence DHE : dihydroethidium nationallicence DioC6(3) : 3,3′-dihexyloxacarbocyanine iodide nationallicence ER : endoplasmatic reticulum nationallicence FITC : fluorescein-5-isothiocyanate nationallicence MOMP : mitochondrial outer membrane permeabilization nationallicence MPT : mitochondrial permeability transition nationallicence PI : propidium iodide nationallicence ROS : reactive oxygen species nationallicence SCC : squamous cell carcinoma nationallicence Δ ψm : mitochondrial electrical transmembrane potential nationallicence Zecchin Karina Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887, Campinas, SP, Brazil aut Seidinger Ana Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887, Campinas, SP, Brazil aut Chiaratti Marcos Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887, Campinas, SP, Brazil aut Degasperi Giovanna Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887, Campinas, SP, Brazil aut Meirelles Flávio Departamento de Ciências Básicas, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo (USP), 13635-900, Pirassununga, SP, Brazil aut Castilho Roger Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887, Campinas, SP, Brazil aut Vercesi Aníbal Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887, Campinas, SP, Brazil aut Journal of Bioenergetics and Biomembranes Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 39/2(2007-04-01), 186-194 0145-479X 39:2<186 2007 39 10863 https://doi.org/10.1007/s10863-007-9076-z text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10863-007-9076-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zecchin Karina Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887, Campinas, SP, Brazil aut NATIONALLICENCE 700 1- Seidinger Ana Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887, Campinas, SP, Brazil aut NATIONALLICENCE 700 1- Chiaratti Marcos Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887, Campinas, SP, Brazil aut NATIONALLICENCE 700 1- Degasperi Giovanna Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887, Campinas, SP, Brazil aut NATIONALLICENCE 700 1- Meirelles Flávio Departamento de Ciências Básicas, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo (USP), 13635-900, Pirassununga, SP, Brazil aut NATIONALLICENCE 700 1- Castilho Roger Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887, Campinas, SP, Brazil aut NATIONALLICENCE 700 1- Vercesi Aníbal Departamento de Patologia Clínica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas (UNICAMP), 13083-887, Campinas, SP, Brazil aut NATIONALLICENCE 773 0- Journal of Bioenergetics and Biomembranes Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 39/2(2007-04-01), 186-194 0145-479X 39:2<186 2007 39 10863 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer