Characterization of 4-O-methyl-ascochlorin-induced apoptosis in comparison with typical apoptotic inducers in human leukemia cell lines.
Apoptosis can be induced by various stimuli such as the ligands of death receptors, chemotherapeutic drugs and irradiation. It is generally believed that chemotherapeutic drugs induce mitochondrial damage, cytochrome c release and activation of caspase-9, leading to apoptosis. Here, we found that an isoprenoid antibiotic, 4-O-methyl ascochlorin, significantly induces typical apoptotic events in Jurkat cells including the degradation of poly (ADP-ribose) polymerase, DNA fragmentation, activation of caspase-3, -9 and -8, and cytochrome c release from mitochondria. Similar to Fas stimulation, 4-O-methyl ascochlorin but not staurosporine, cycloheximide and actinomycin D, induced apoptosis in SKW6.4 cells, in which apoptosis is strongly dependent on death-inducing signaling-complex. Bcl-2 overexpression in Jurkat cells completely suppressed the apoptosis, but procaspase-9 processing was partially induced. A caspase-8 inhibitor, IETD-fmk, effectively suppressed poly (ADP-ribose) polymerase cleavage and cytochrome c release. However, 4-O-methyl ascochlorin induced apoptosis in Jurkat cells deficient of caspase-8 or Fas-associated death domain protein. These results suggest that 4-O-methyl ascochlorin induces apoptosis through the mechanism distinct from conventional apoptosis inducers.
Tsuruga
M
M
Department of Biotechnology, Institute of Research and Innovation, 1201 Takada, Kashiwa, Chiba 277-0861, Japan.
Nakajima
H
H
Ozawa
S
S
Togashi
M
M
Chang
Y-C
YC
Ando
K
K
Magae
J
J
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000502:physiology; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D061945:Caspase Inhibitors; D020169:Caspases / Q000235:genetics / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D045304:Cytochromes c / Q000378:metabolism; D053938:DNA Fragmentation / Q000187:drug effects; D003609:Dactinomycin / Q000494:pharmacology; D053200:Fas-Associated Death Domain Protein; D006801:Humans; D007075:Immunoglobulin M / Q000494:pharmacology; D019169:Jurkat Cells; D009842:Oligopeptides / Q000494:pharmacology; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000502:physiology; D019311:Staurosporine / Q000494:pharmacology; D013729:Terpenes / Q000494:pharmacology*; D019014:fas Receptor / Q000276:immunology
D048868:Adaptor Proteins, Signal Transducing; D061945:Caspase Inhibitors; C505533:FADD protein, human; D053200:Fas-Associated Death Domain Protein; D007075:Immunoglobulin M; D009842:Oligopeptides; D019253:Proto-Oncogene Proteins c-bcl-2; D013729:Terpenes; D019014:fas Receptor; C425644:isoleucyl-glutamyl-threonyl-aspartic acid fluoromethyl ketone; D003609:Dactinomycin; C031515:4-O-methylascochlorin; D045304:Cytochromes c; D003513:Cycloheximide; D011065:Poly(ADP-ribose) Polymerases; C505407:CASP3 protein, human; C505530:CASP8 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases; D019311:Staurosporine