title: Acetoxycycloheximide (E-73) rapidly induces apoptosis mediated by the release of cytochrome c via activation of c-Jun N-terminal kinase.
abstract: Cycloheximide (CHX) is an inhibitor of protein synthesis and commonly used to modulate death receptor-mediated apoptosis or to induce apoptosis in a number of normal and transformed cells. In this study we show that a close structural derivative of CHX, acetoxycycloheximide (E-73) induced rapid processing of procaspases and subsequent apoptosis with much higher efficacy than CHX in human leukemia Jurkat T cells. E-73 induced the release of cytochrome c from mitochondria even in the presence of the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethyl ketone. The Bcl-2 family protein Bcl-x(L) suppressed cytochrome c release as well as processing of procaspases-3, -8, and -9 in E-73-treated cells. In Jurkat T cells transfected with the caspase-8 modulator FLIP(L), E-73 still induced activation of procaspase-3 and subsequent apoptosis, suggesting that the caspase-8 activity is dispensable for apoptosis. In contrast to CHX, E-73 drastically induced activation of extracellular signal-regulated kinase, c-Jun N-terminal kinase (JNK), and p38 MAP kinase. Inhibitory profiles of small-molecular kinase inhibitors revealed that JNK activation was critical for induction of cytochrome c release in E-73-induced apoptosis. Thus, our present results demonstrate that E-73, unlike CHX, induces strong activation of the JNK pathway and triggers rapid apoptosis mediated by the release of cytochrome c.
authors.affiliation: Center for Biological Resources and Informatics, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: Kimiko
authors.initials: K
authors.lastname: Kadohara
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Tsukumo
authors.forename: Hikaru
authors.initials: H
authors.lastname: Sugimoto
authors.forename: Masayuki
authors.initials: M
authors.lastname: Igarashi
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nagai
authors.forename: Takao
authors.initials: T
authors.lastname: Kataoka
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D020169:Caspases / Q000502:physiology; D002467:Cell Nucleus / Q000187:drug effects; D003513:Cycloheximide / Q000031:analogs & derivatives* / Q000494:pharmacology*; D003520:Cyclophosphamide / Q000494:pharmacology; D045304:Cytochromes c / Q000378:metabolism*; D053938:DNA Fragmentation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000502:physiology; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D019169:Jurkat Cells; D010766:Phosphorylation; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000502:physiology; D051020:bcl-X Protein
chemical_list: C494811:BCL2L1 protein, human; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; C506386:CFLAR protein, human; D047908:Intracellular Signaling Peptides and Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051020:bcl-X Protein; D003520:Cyclophosphamide; D045304:Cytochromes c; D003513:Cycloheximide; D048031:JNK Mitogen-Activated Protein Kinases; D020169:Caspases; C004434:acetoxycycloheximide