BAPTA blocks DNA fragmentation and chromatin condensation downstream of caspase-3 and DFF activation in HT-induced apoptosis in HL-60 cells.
DFF ((DNA Fragmentation Factor) is a heterodimer composed of 40 kDa (DFF40, CAD) and 45 kDa (DFF45, ICAD) subunits. During apoptosis, activated caspase-3 cleaves DFF45 and activates DFF40, a DNase that targets nucleosomal linker region and cleaves chromatin DNA into nucleosomal fragments. We have previously reported that HT induced apoptosis in HL-60 cells, and intracellular Ca(2+) chelator BAPTA blocked apoptosis-associated DNA fragmentation induced by HT. We report here that HT also induced activation of caspase-3 and cleavage of DFF45. BAPTA prevented neither the caspase-3 activation nor the cleavage of DFF45. Mitochondrial membrane potential was disrupted in BAPTA-AM treated cells. However, BAPTA did prevent DNA fragmentation and chromatin condensation in HT-treated cells. These data suggest a novel role for intracellular calcium in regulating apoptotic nuclease that causes DNA fragmentation and chromatin condensation.
Zhang
M
M
Department of Biology, Beijing Normal University, Beijing, 100875, People's Republic of China.
Li
Y
Y
Zhang
H
H
Xue
S
S
D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism*; D002843:Chromatin / Q000187:drug effects*; D053938:DNA Fragmentation; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology*; D018922:HL-60 Cells; D006248:Harringtonines / Q000494:pharmacology; D006801:Humans; D011506:Proteins / Q000378:metabolism
D000970:Antineoplastic Agents; D051017:Apoptosis Regulatory Proteins; D002843:Chromatin; D006248:Harringtonines; D011506:Proteins; C109664:caspase-activated DNase inhibitor; C062500:harringtonin; D004533:Egtazic Acid; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid