Possible involvement of caspase-6 and -7 but not caspase-3 in the regulation of hypoxia-induced apoptosis in tube-forming endothelial cells.
We recently reported that a broad-spectrum caspase inhibitor zVAD-fmk failed, while p38 inhibitor SB203580 succeeded, to prevent chromatin condensation and nuclear fragmentation induced by hypoxia in tube-forming HUVECs. In this study, we investigated the reasons for zVAD-fmk's inability to inhibit these morphological changes at the molecular level. The inhibitor effectively inhibited DNA ladder formation and activation of caspase-3 and -6, but it surprisingly failed to inhibit caspase-7 activation. On the other hand, SB203580 successfully inhibited all of these molecular events. When zLEHD-fmk, which specifically inhibits initiator caspase-9 upstream of caspase-3, was used, it inhibited caspase-3 activation but failed to inhibit caspase-6 and -7 activation. It also failed to inhibit hypoxia-induced chromatin condensation, nuclear fragmentation and DNA ladder formation. Taken together, our results indicate that, during hypoxia, caspase-7 is responsible for chromatin condensation and nuclear fragmentation while caspase-6 is responsible for DNA ladder formation.
Eguchi
Ryoji
R
Department of Thoracic Oncology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan.
Toné
Shigenobu
S
Suzuki
Akio
A
Fujimori
Yoshihiro
Y
Nakano
Takashi
T
Kaji
Kazuhiko
K
Ohta
Toshiro
T
D000199:Actins / Q000378:metabolism; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D053148:Caspase 3 / Q000378:metabolism*; D053178:Caspase 6 / Q000378:metabolism*; D053179:Caspase 7 / Q000378:metabolism*; D053453:Caspase 9 / Q000378:metabolism; D061945:Caspase Inhibitors; D015687:Cell Hypoxia / Q000502:physiology; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects; D002843:Chromatin / Q000187:drug effects; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D053960:DNA Breaks / Q000187:drug effects; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D034904:Lamin Type A / Q000378:metabolism; D008954:Models, Biological; D018919:Neovascularization, Physiologic / Q000187:drug effects; D009842:Oligopeptides / Q000494:pharmacology; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology
D000199:Actins; D000590:Amino Acid Chloromethyl Ketones; D061945:Caspase Inhibitors; D002843:Chromatin; D015853:Cysteine Proteinase Inhibitors; D007093:Imidazoles; D034904:Lamin Type A; D009842:Oligopeptides; D047428:Protein Kinase Inhibitors; D011725:Pyridines; C403754:benzyloxycarbonyl-leucyl-glutamyl-histidyl-aspartic acid fluoromethyl ketone; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D011065:Poly(ADP-ribose) Polymerases; D053148:Caspase 3; D053178:Caspase 6; D053179:Caspase 7; D053453:Caspase 9; C093642:SB 203580