Mutant K-Ras increases GSK-3β gene expression via an ETS-p300 transcriptional complex in pancreatic cancer

Oncogene. 2011 Aug 25;30(34):3705-15. doi: 10.1038/onc.2011.90. Epub 2011 Mar 28.

Abstract

Glycogen synthase kinase-3 beta (GSK-3β) is overexpressed in a number of human malignancies and has been shown to contribute to tumor cell proliferation and survival. Although regulation of GSK-3β activity has been extensively studied, the mechanisms governing GSK-3β gene expression are still unknown. Using pancreatic cancer as a model, we find that constitutively active Ras signaling increases GSK-3β gene expression via the canonical mitogen-activated protein kinase signaling pathway. Analysis of the mechanism revealed that K-Ras regulates the expression of this kinase through two highly conserved E-twenty six (ETS) binding elements within the proximal region. Furthermore, we demonstrate that mutant K-Ras enhances ETS2 loading onto the promoter, and ETS requires its transcriptional activity to increase GSK-3β gene transcription in pancreatic cancer cells. Lastly, we show that ETS2 cooperates with p300 histone acetyltransferase to remodel chromatin and promote GSK-3β expression. Taken together, these results provide a general mechanism for increased expression of GSK-3β in pancreatic cancer and perhaps other cancers, where Ras signaling is deregulated.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chromatin Assembly and Disassembly
  • Chromatin Immunoprecipitation
  • Genes, ras*
  • Glycogen Synthase Kinase 3 / genetics*
  • Glycogen Synthase Kinase 3 / metabolism
  • Glycogen Synthase Kinase 3 beta
  • Humans
  • Immunohistochemistry
  • MAP Kinase Signaling System
  • Mice
  • Mice, Transgenic
  • Mutation*
  • Pancreatic Neoplasms / genetics*
  • Pancreatic Neoplasms / pathology
  • Promoter Regions, Genetic
  • RNA-Binding Protein EWS / genetics*
  • Transcription, Genetic
  • p300-CBP Transcription Factors / genetics*

Substances

  • RNA-Binding Protein EWS
  • p300-CBP Transcription Factors
  • GSK3B protein, human
  • Glycogen Synthase Kinase 3 beta
  • Gsk3b protein, mouse
  • Glycogen Synthase Kinase 3