GSK-3β Governs Inflammation-Induced NFATc2 Signaling Hubs to Promote Pancreatic Cancer Progression

Mol Cancer Ther. 2016 Mar;15(3):491-502. doi: 10.1158/1535-7163.MCT-15-0309. Epub 2016 Jan 28.

Abstract

We aimed to investigate the mechanistic, functional, and therapeutic role of glycogen synthase kinase 3β (GSK-3β) in the regulation and activation of the proinflammatory oncogenic transcription factor nuclear factor of activated T cells (NFATc2) in pancreatic cancer. IHC, qPCR, immunoblotting, immunofluorescence microscopy, and proliferation assays were used to analyze mouse and human tissues and cell lines. Protein-protein interactions and promoter regulation were analyzed by coimmunoprecipitation, DNA pulldown, reporter, and ChIP assays. Preclinical assays were performed using a variety of pancreatic cancer cells lines, xenografts, and a genetically engineered mouse model (GEMM). GSK-3β-dependent SP2 phosphorylation mediates NFATc2 protein stability in the nucleus of pancreatic cancer cells stimulating pancreatic cancer growth. In addition to protein stabilization, GSK-3β also maintains NFATc2 activation through a distinct mechanism involving stabilization of NFATc2-STAT3 complexes independent of SP2 phosphorylation. For NFATc2-STAT3 complex formation, GSK-3β-mediated phosphorylation of STAT3 at Y705 is required to stimulate euchromatin formation of NFAT target promoters, such as cyclin-dependent kinase-6, which promotes tumor growth. Finally, preclinical experiments suggest that targeting the NFATc2-STAT3-GSK-3β module inhibits proliferation and tumor growth and interferes with inflammation-induced pancreatic cancer progression in Kras(G12D) mice. In conclusion, we describe a novel mechanism by which GSK-3β fine-tunes NFATc2 and STAT3 transcriptional networks to integrate upstream signaling events that govern pancreatic cancer progression and growth. Furthermore, the therapeutic potential of GSK-3β is demonstrated for the first time in a relevant Kras and inflammation-induced GEMM for pancreatic cancer.

Publication types

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

MeSH terms

  • Animals
  • Binding Sites
  • Cell Line, Tumor
  • Disease Models, Animal
  • Disease Progression
  • Gene Expression
  • Genes, ras
  • Glycogen Synthase Kinase 3 beta / metabolism*
  • Humans
  • Inflammation / metabolism*
  • Mice
  • Mice, Knockout
  • Multiprotein Complexes / metabolism
  • NFATC Transcription Factors / genetics
  • NFATC Transcription Factors / metabolism*
  • Nucleotide Motifs
  • Pancreatic Neoplasms / genetics
  • Pancreatic Neoplasms / metabolism*
  • Pancreatic Neoplasms / pathology*
  • Phosphorylation
  • Protein Binding
  • Protein Stability
  • STAT3 Transcription Factor / metabolism
  • Signal Transduction*

Substances

  • Multiprotein Complexes
  • NFATC Transcription Factors
  • STAT3 Transcription Factor
  • Glycogen Synthase Kinase 3 beta