Transcriptional activation of cyclooxygenase-2 in Wnt-1-transformed mouse mammary epithelial cells Academic Article uri icon

Overview

MeSH Major

  • Breast Neoplasms
  • Cell Transformation, Neoplastic
  • Isoenzymes
  • Prostaglandin-Endoperoxide Synthases
  • Proto-Oncogene Proteins
  • Transcriptional Activation
  • Zebrafish Proteins

abstract

  • Wnt-1 acts as a mammary oncogene when ectopically expressed in the mouse mammary gland. APC is a tumor suppressor gene, mutations in which cause intestinal tumorigenesis in humans and rodents. Both Wnt-1 expression and APC mutation activate a common signaling pathway involving transcriptional activation mediated by beta-catenin/Tcf complexes, but few targets relevant to carcinogenesis have yet been identified. Expression of the inducible prostaglandin synthase cyclooxygenase-2 appears critical for intestinal tumorigenesis resulting from APC mutation, suggesting that cyclooxygenase-2 might be a transcriptional target for beta-catenin/Tcf complexes. Here, we have investigated the effect of Wnt-1 on cyclooxygenase-2 expression. Wnt-1 expression in the mouse mammary epithelial cell lines RAC311 and C57MG induces stabilization of cytosolic beta-catenin and morphological transformation. Expression of Wnt-1 in these cells caused transcriptional up-regulation of the cyclooxygenase-2 gene, resulting in increased levels of cyclooxygenase-2 mRNA and protein. Prostaglandin E2 production was increased as a consequence of the elevated cyclooxygenase-2 activity and could be decreased by treatment with a selective cyclooxygenase-2 inhibitor. Cyclooxygenase-2 thus appears to be a common downstream target for APC mutation and Wnt-1 expression. In view of the critical role of cyclooxygenase-2 in intestinal tumorigenesis, cyclooxygenase-2 up-regulation in response to Wnt signaling may contribute to Wnt-induced mammary carcinogenesis.

publication date

  • April 1999

Research

keywords

  • Academic Article

Identity

Language

  • eng

PubMed ID

  • 10197631

Additional Document Info

start page

  • 1572

end page

  • 7

volume

  • 59

number

  • 7