Inhibition of caspase-3 by Survivin prevents Wee1 Kinase degradation and promotes cell survival by maintaining phosphorylation of p34Cdc2

Javier Rivera Guzman, Seiji Fukuda, Louis M. Pelus

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

The anti-apoptotic protein Survivin and the cyclin-dependent kinase p34Cdc2 regulate cell cycle progression and apoptosis. p34Cdc2 activation is required for its pro-apoptotic activity and phosphorylation of p34Cdc2 at Tyrosine-15 (Tyr15) maintains p34Cdc2 in an inactive state. In BaF3 IL-3-dependent murine hematopoietic cells, over-expression of wild-type (wt)-Survivin increased Tyrosine phosphorylation of p34Cdc2, while over-expression of dominant-negative (dn) T34A-Survivin decreased Tyr15 phosphorylation. The increased phospho-Tyr15 levels associated with ectopic wt-Survivin directly correlated with enhanced BaF3 cell survival upon growth factor withdrawal, while conversely, low phospho-Tyr15 levels and decreased survival were seen in BaF3 cells expressing ectopic dn-Survivin. Tyrosine-15 phosphorylation of p34Cdc2 is mediated by the Wee1 Kinase, a known target of caspase-3. In BaF3 cells over-expressing wt-Survivin, 2-fold higher levels of Wee1 protein were detected compared to cells expressing vector or dn-Survivin. Treatment of control vector-transduced BaF3 cells with the selective caspase-3 inhibitor Ac-DEVD-CHO increased p34Cdc2-Tyr15 phosphorylation and Wee1 protein levels. In a similar fashion, over-expression of wt-Survivin maintained high levels of phospho-Tyr15-p34Cdc2 and Wee1 protein. Since Survivin requires Hsp90 for stability, we treated cells with the Hsp90 inhibitors AICAR and 17-AAG to further link Survivin to blocking p34Cdc2 activation. Treatment of BaF3 cells expressing ectopic wt-Survivin with AICAR or 17-AAG significantly reduced p34Cdc2-Tyr15 phosphorylation compared to vehicle-treated controls. These results suggest that Survivin protects the p34Cdc2-Tyr15-targeting kinase Wee1 from degradation by blocking caspase-3 activation leading to inhibition of the pro-apoptotic function of p34Cdc2 and enhanced cell survival.

Original languageEnglish (US)
Pages (from-to)264-273
Number of pages10
JournalGene Therapy and Molecular Biology
Volume13
Issue number2
StatePublished - Dec 1 2009

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Keywords

  • Apoptosis
  • Caspase-3
  • p34Cdc2
  • Survivin
  • Wee1

ASJC Scopus subject areas

  • Molecular Biology
  • Molecular Medicine

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