title: Chemotherapeutic drug activation of the AP24 protease in apoptosis: requirement for caspase 3-like-proteases.
abstract: AP24 is a serine protease that is activated during TNF or UV light-induced apoptosis and stimulates DNA fragmentation in isolated nuclei. The present study determined whether apoptosis induced by chemotherapeutic drugs resulted in activation of AP24 and examined the possible relationship to caspase activity. We showed that an inhibitor of AP24, DK120, could block DNA fragmentation induced in three leukemia cell lines (U937, HL-60, and CEM) by various DNA-damaging drugs including etoposide, camptothecin, chlorambucil, and the CC1065-related drug, YW201. Etoposide-induced activation of intracellular DEVD-pNa cleaving activity and apoptosis was suppressed by low micromolar concentrations of cell-permeable inhibitors of caspase-3. Furthermore, these inhibitors also suppressed activation of AP24. In contrast, DK120 did not prevent etoposide activation of DEVD-pNa cleaving activity, nor did it prevent cleavage of poly(ADP-ribose) polymerase. AP24 isolated from apoptotic cells following treatment with etoposide activated DNA fragmentation in isolated normal nuclei and was inhibited by DK120, but not by caspase inhibitors. This evidence shows that activation of caspase 3-like proteases generates signals that contribute to the activation of AP24 which may then induce nuclear DNA fragmentation in chemotherapeutic drug-induced apoptosis.
authors.affiliation: Palo Alto Institute of Molecular Medicine, Mountain View, California 94043, USA.
authors.forename: S C
authors.initials: SC
authors.lastname: Wright
authors.forename: U
authors.initials: U
authors.lastname: Schellenberger
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: D H
authors.initials: DH
authors.lastname: Kinder
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000528:radiation effects; D001896:Boron Compounds / Q000494:pharmacology; D053148:Caspase 3; D020169:Caspases; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D053938:DNA Fragmentation / Q000528:radiation effects; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000378:metabolism*; D005047:Etoposide / Q000494:pharmacology; D006801:Humans; D009842:Oligopeptides / Q000494:pharmacology; D012697:Serine Endopeptidases / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014466:Ultraviolet Rays
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D001896:Boron Compounds; D004792:Enzyme Precursors; D009842:Oligopeptides; D015842:Serine Proteinase Inhibitors; C112293:carbobenzoxy-alanyl-alanyl-borophenylalanyl; D005047:Etoposide; C108734:AP24 apoptotic protease; D012697:Serine Endopeptidases; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D003546:Cysteine Endopeptidases