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Dose-dependent effects of the caspase inhibitor Q-VD-OPh on different apoptosis-related processes

Kateřina Kuželová1, Dana Grebeňová, Barbora Brodská

  • 1Department of Cellular Biochemistry, Institute of Hematology and Blood Transfusion, U Nemocnice 2, 128 20 Prague 2, Czech Republic. katerina.kuzelova@uhkt.cz

Journal of Cellular Biochemistry
|July 14, 2011
PubMed

Insights

The pan-caspase inhibitor Q-VD-OPh effectively blocks caspase activity and DNA fragmentation at low concentrations. It also prevents PARP cleavage and preserves cell membrane integrity during apoptosis.

Area of Science:

  • Biochemistry and Molecular Biology
  • Cell Biology
  • Pharmacology

Background:

  • Apoptosis is a crucial biological process involving caspases.
  • Pan-caspase inhibitors are vital tools for studying apoptosis.
  • Q-VD-OPh is a potent inhibitor with potential therapeutic applications.

Purpose of the Study:

  • To comprehensively evaluate the efficacy of Q-VD-OPh in inhibiting various apoptotic markers.
  • To compare Q-VD-OPh with another pan-caspase inhibitor, z-VAD-fmk.
  • To investigate the dose-dependent effects of Q-VD-OPh on cellular processes during apoptosis.

Main Methods:

  • Analysis of caspase-3, -7, and -8 activity using fluorometric assays and immunoblots.
  • Assessment of Poly (ADP-ribose) polymerase (PARP-1) cleavage.
  • Evaluation of DNA fragmentation and cell membrane integrity (Trypan blue exclusion test).
  • Measurement of cellular adhesivity to fibronectin.
  • Utilized JURL-MK1 and HL60 cell lines with imatinib mesylate and suberoylanilide hydroxamic acid as apoptosis inducers.

Main Results:

  • Q-VD-OPh potently inhibited caspase-3 and -7 activity at 0.05 µM and caspase-8 at low concentrations.
  • Higher concentrations (10 µM) of Q-VD-OPh were required for complete PARP-1 cleavage inhibition.
  • DNA fragmentation and cell membrane dysfunction were prevented at 2 µM Q-VD-OPh.
  • Q-VD-OPh (10 µM) inhibited drug-induced loss of fibronectin adhesion in JURL-MK1 cells.
  • Mitochondrial antigen 7A6 exposition occurred independently of Q-VD-OPh, suggesting its use in detecting early apoptotic events.
  • Q-VD-OPh demonstrated significantly higher efficiency than z-VAD-fmk in inhibiting caspase-3 and DNA fragmentation.

Conclusions:

  • Q-VD-OPh is a highly effective pan-caspase inhibitor with superior potency compared to z-VAD-fmk.
  • Its efficacy spans multiple apoptotic pathways, including caspase activation, DNA fragmentation, and PARP cleavage.
  • Q-VD-OPh preserves cellular integrity and adhesion during apoptosis, highlighting its potential in therapeutic strategies targeting apoptotic processes.

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