Nuclear caspase-3 and caspase-7 activation, and poly(ADP-ribose) polymerase cleavage are early events in camptothecin-induced apoptosis.
Chemotherapy-induced apoptosis by DNA-damaging drugs is thought to be generally dependent on the release of cytochrome c and the subsequent activation of caspase-9 and -3. However, the molecular mechanism of how damaged DNA triggers the apoptotic process is not clear. To better understand the mechanisms underlying this process, we examined drug-induced apoptosis in cultured H-460 cells. Using cell fractionation, western blotting, and immunofluorescence assays, we show that the activation of nuclear caspases-7 and -3, and poly(ADP-ribose) polymerase (PARP) cleavage, are early events in camptothecin-induced apoptosis. Moreover, we demonstrate that these events precede the release of cytochrome c and apoptotic inducing factor, and the activation of caspases 2, 8, 9 and 12. Together our results suggest that drugs acting at the DNA level can initiate apoptosis via nuclear caspase activation.
Rodríguez-Hernández
A
A
Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide, Sevilla, Spain.
Brea-Calvo
G
G
Fernández-Ayala
D J M
DJ
Cordero
M
M
Navas
P
P
Sánchez-Alcázar
J A
JA
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology*; D002166:Camptothecin / Q000494:pharmacology*; D053148:Caspase 3 / Q000378:metabolism*; D053179:Caspase 7 / Q000378:metabolism*; D061945:Caspase Inhibitors; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000187:drug effects / Q000201:enzymology; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004249:DNA Damage; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D009842:Oligopeptides / Q000494:pharmacology; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*
D000590:Amino Acid Chloromethyl Ketones; D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D009842:Oligopeptides; C110772:benzoylcarbonyl-aspartyl-glutamyl-valyl-aspartyl-fluoromethyl ketone; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; C505407:CASP3 protein, human; C505520:CASP7 protein, human; D053148:Caspase 3; D053179:Caspase 7; D002166:Camptothecin