Apoptosis induction by T-2 toxin: activation of caspase-9, caspase-3, and DFF-40/CAD through cytosolic release of cytochrome c in HL-60 cells.
The molecules participating in apoptosis induced by T-2 toxin in human leukemia HL-60 cells were investigated. The rank order of the potency of trichothecene mycotoxins to induce internucleosomal DNA fragmentation was found to be T-2, satratoxin G, roridin A >> diacetoxyscirpenol > baccharin B-5 >> nivalenol, deoxynivalenol, 3-acetyldeoxynivalenol, fusarenon-X, baccharin B-4=vehicle control. Western blot analysis of caspase-3 in T-2-treated cells clearly indicated the appearance of its catalytically active fragment of 17-kDa. Increased caspase-3 activity was also detected by using a fluorogenic substrate, DEVD-AMC. Next, cells exposed to T-2 led to cleavage of PARP from its native 116-kDa form to the 85-kDa product. Moreover, DFF-45/ICAD were cleaved to give a 12.5-kDa fragment via T-2 treatment. T-2 caused the release of cytochrome c from mitochondria into the cytosol. Increased enzymic activity of caspase-9 on LEHD-AMC was shown. These data indicate that T-2-induced apoptosis involves activation of caspase-3 and DFF-40/CAD through cytosolic accumulation of cytochrome c along with caspase-9 activation.
Nagase
M
M
Department of Life Sciences, Faculty of Agriculture, Kagawa University, Japan. nagase@ag.kagawa-u.ac.jp
Alam
M M
MM
Tsushima
A
A
Yoshizawa
T
T
Sakato
N
N
D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism*; D003574:Cytochrome c Group / Q000378:metabolism*; D003600:Cytosol / Q000187:drug effects / Q000201:enzymology*; D053938:DNA Fragmentation; D003851:Deoxyribonucleases / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D018922:HL-60 Cells; D006801:Humans; D007202:Indicators and Reagents; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology; D009707:Nucleosomes / Q000737:chemistry / Q000187:drug effects; D000075223:Poly-ADP-Ribose Binding Proteins; D013605:T-2 Toxin / Q000633:toxicity*
D003574:Cytochrome c Group; D007202:Indicators and Reagents; D009707:Nucleosomes; D000075223:Poly-ADP-Ribose Binding Proteins; C113696:DFFB protein, human; D003851:Deoxyribonucleases; C505407:CASP3 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases; D013605:T-2 Toxin