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In Vivo Biosensor Tracks Non-apoptotic Caspase Activity in Drosophila
Published on: November 27, 2016
Unspecific activation of caspases during the induction of apoptosis by didemnin B in human cell lines
K L Johnson1, D R Grubb, A Lawen
1Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.
Abstract:
Caspases have been implicated in the induction of apoptosis in most systems studied. The importance of caspases for apoptosis was further investigated using the system of didemnin B-induced apoptosis. We found that benzyloxycarbonyl-VAD-fluoromethylketone, a general caspase inhibitor, inhibits didemnin B-induced apoptosis in HL-60 and Daudi cells. Acetyl-YVAD-chloromethylketone, a caspase-1-like activity inhibitor, inhibits didemnin B-induced apoptosis in Daudi cells, whereas the caspase-3-like activity inhibitor, acetyl-DEVD-aldehyde, has no effect. Using immunoblots to investigate cleavage of caspases-1 and -3, we found that both caspases are activated in both cell lines. We showed that the caspase substrate poly(ADP-ribose)polymerase is cleaved in these cells after didemnin B treatment. In both cell lines, poly(ADP-ribose)polymerase cleavage is inhibited by benzyloxycarbonyl-VAD-fluoromethylketone and also by acetyl-YVAD-chloromethylketone in Daudi cells. These results indicate that a caspase(s) other than caspase-3 is required for didemnin B-induced apoptosis. We show that caspases may be activated during apoptosis that are not required for the progression of apoptosis.
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