Beta catenin is degraded by both caspase-3 and proteasomal activity during resveratrol-induced apoptosis in HeLa cells in a GSK3β-independent manner

Indian J Biochem Biophys. 2015 Feb;52(1):7-13.

Abstract

Increased activity of β-catenin, an important transcriptional activator for survival and proliferation-associated genes has been linked with many cancers. We examined whether β-catenin is a target of resveratrol and whether its degradation contributes to the pro-apoptotic effects of resveratrol. HeLa cells were exposed to 60 μM resveratrol for 48 h. Apoptosis was confirmed by measurement of annexin V externalization, caspase-3 activation and DNA fragmentation. Induction of apoptosis was observed as early as 12 h, when both caspase-3 activation and PARP (poly ADP ribose polymerase) cleavage occurred. Nuclear β-catenin levels remained unchanged for 48 h during resveratrol exposure. However, extranuclear cell lysate β-catenin underwent a decrease at a late stage of apoptosis namely at 36-48 h. Alterations in the phosphorylation status of Akt/GSK3β were not observed during resveratrol-induced apoptosis. Furthermore, inhibition of GSK3β activity which is. largely responsible for β-catenin degradation failed to influence β-catenin stability. However, inhibition of caspase-3 activity prevented the decline in β-catenin levels at 36-48 h of resveratrol exposure. Lactacystin, a proteosomal inhibitor also prevented the degradation of β-catenin by resveratrol. In conclusion, resveratrol induced apoptosis in HeLa cells in an Akt/GSK3β-independent manner and down-regulated β-catenin levels during apoptosis through action of caspase-3 and proteasomal degradation, independent of GSK3β-mediated phosphorylation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / drug effects
  • Caspase 3 / metabolism*
  • Glycogen Synthase Kinase 3 / metabolism*
  • Glycogen Synthase Kinase 3 beta
  • HeLa Cells
  • Humans
  • Proteasome Endopeptidase Complex / metabolism
  • Resveratrol
  • Stilbenes / pharmacology*
  • beta Catenin / metabolism*

Substances

  • Stilbenes
  • beta Catenin
  • GSK3B protein, human
  • Glycogen Synthase Kinase 3 beta
  • Glycogen Synthase Kinase 3
  • Caspase 3
  • Proteasome Endopeptidase Complex
  • Resveratrol