Dose-dependent effects of the caspase inhibitor Q-VD-OPh on different apoptosis-related processes
✍ Scribed by Kateřina Kuželová; Dana Grebeňová; Barbora Brodská
- Publisher
- John Wiley and Sons
- Year
- 2011
- Tongue
- English
- Weight
- 335 KB
- Volume
- 112
- Category
- Article
- ISSN
- 0730-2312
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✦ Synopsis
Abstract
The effects of the pan‐caspase inhibitor Q‐VD‐OPh on caspase activity, DNA fragmentation, PARP cleavage, 7A6 exposition, and cellular adhesivity to fibronectin were analyzed in detail in three different apoptotic systems involving two cell lines (JURL‐MK1 and HL60) and two apoptosis inducers (imatinib mesylate and suberoylanilide hydroxamic acid). Q‐VD‐OPh fully inhibited caspase‐3 and ‐7 activity at 0.05 µM concentration as indicated both by the measurement of the rate of Ac‐DEVD‐AFC cleavage and anti‐caspase immunoblots. Caspase‐8 was also inhibited at low Q‐VD‐OPh concentrations. On the other hand, significantly higher Q‐VD‐OPh dose (10 µM) was required to fully prevent the cleavage of PARP‐1. DNA fragmentation and disruption of the cell membrane functionality (Trypan blue exclusion test) were both prevented at 2 µM Q‐VD‐OPh while 10 µM inhibitor was needed to inhibit the drug‐induced loss of cellular adhesivity to fibronectin which was observed in JURL‐MK1 cells. The exposition of the mitochondrial antigen 7A6 occurred independently of Q‐VD‐OPh addition and may serve to the detection of cumulative incidence of the cells which have initiated the apoptosis. Our results show that Q‐VD‐OPh efficiency in the inhibition of caspase‐3 activity and DNA fragmentation in the whole‐cell environment is about two orders of magnitude higher than that of z‐VAD‐fmk. This difference is not due to a slow permeability of the latter through the cytoplasmic membrane. J. Cell. Biochem. 112: 3334–3342, 2011. © 2011 Wiley Periodicals, Inc.