PAC-1 Activates Procaspase-3 in Vitro through Relief of Zinc-Mediated Inhibition

Quinn Peterson, David R. Goode, Diana C. West, Kara N. Ramsey, Joy J Y Lee, Paul J. Hergenrother

Research output: Contribution to journalArticle

99 Citations (Scopus)

Abstract

The direct induction of apoptosis has emerged as a powerful anticancer strategy, and small molecules that either inhibit or activate certain proteins in the apoptotic pathway have great potential as novel chemotherapeutic agents. Central to apoptosis is the activation of the zymogen procaspase-3 to caspase-3. Caspase-3 is the key "executioner" caspase, catalyzing the hydrolysis of a multitude of protein substrates within the cell. Interestingly, procaspase-3 levels are often elevated in cancer cells, suggesting a compound that directly stimulates the activation of procaspase-3 to caspase-3 could selectively induce apoptosis in cancer cells. We recently reported the discovery of a compound, PAC-1, which enhances procaspase-3 activity in vitro and induces apoptotic death in cancer cells in culture and in mouse xenograft models. Described herein is the mechanism by which PAC-1 activates procaspase-3 in vitro. We show that zinc inhibits the enzymatic activity of procaspase-3 and that PAC-1 strongly activates procaspase-3 in buffers that contain zinc. PAC-1 and zinc form a tight complex with one another, with a dissociation constant of approximately 42 nM. The combined data indicate that PAC-1 activates procaspase-3 in vitro by sequestering inhibitory zinc ions, thus allowing procaspase-3 to autoactivate itself to caspase-3. The small-molecule-mediated activation of procaspases has great therapeutic potential and thus this discovery of the in vitro mechanism of action of PAC-1 is critical to the development and optimization of other procaspase-activating compounds.

Original languageEnglish (US)
Pages (from-to)144-158
Number of pages15
JournalJournal of Molecular Biology
Volume388
Issue number1
DOIs
StatePublished - Apr 24 2009
Externally publishedYes

Fingerprint

Caspase 3
Zinc
Apoptosis
2-carboxyarabinitol 1-phosphate
In Vitro Techniques
Neoplasms
Enzyme Precursors
Caspases
Heterografts
Buffers
Proteins
Hydrolysis
Cell Culture Techniques
Ions

Keywords

  • apoptosis
  • cancer
  • PAC-1
  • procaspase-3
  • zinc

ASJC Scopus subject areas

  • Molecular Biology

Cite this

Peterson, Q., Goode, D. R., West, D. C., Ramsey, K. N., Lee, J. J. Y., & Hergenrother, P. J. (2009). PAC-1 Activates Procaspase-3 in Vitro through Relief of Zinc-Mediated Inhibition. Journal of Molecular Biology, 388(1), 144-158. https://doi.org/10.1016/j.jmb.2009.03.003

PAC-1 Activates Procaspase-3 in Vitro through Relief of Zinc-Mediated Inhibition. / Peterson, Quinn; Goode, David R.; West, Diana C.; Ramsey, Kara N.; Lee, Joy J Y; Hergenrother, Paul J.

In: Journal of Molecular Biology, Vol. 388, No. 1, 24.04.2009, p. 144-158.

Research output: Contribution to journalArticle

Peterson, Quinn ; Goode, David R. ; West, Diana C. ; Ramsey, Kara N. ; Lee, Joy J Y ; Hergenrother, Paul J. / PAC-1 Activates Procaspase-3 in Vitro through Relief of Zinc-Mediated Inhibition. In: Journal of Molecular Biology. 2009 ; Vol. 388, No. 1. pp. 144-158.
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