STAT6 mediates interleukin-4 growth inhibition in human breast cancer cells

Jennifer L. Gooch, Barbara Christy, Douglas Yee

Research output: Contribution to journalArticle

58 Scopus citations

Abstract

In addition to acting as a hematopoietic growth factor, interleukin-4 (IL-4) inhibits growth of some transformed cells in vitro and in vivo. In this study, we show that insulin receptor substrate (IRS)-1, IRS-2, and signal transducer and activator of transcription 6 (STAT6) are phosphorylated following IL-4 treatment in MCF-7 breast cancer cells. STAT6 DNA binding is enhanced by IL-4 treatment. STAT6 activation occurs even after IRS-1 depletion, suggesting the two pathways are independent. To examine the role of STAT6 in IL-4-mediated growth inhibition and apoptosis, a full-length STAT6 cDNA was transfected into MCF-7 cells. Transient overexpression of STAT6 resulted in both cytoplasmic and nuclear expression of the protein, increased DNA binding in response to IL-4, and increased transactivation of an IL-4 responsive promoter. In STAT6-transfected cells, basal proliferation was reduced whereas apoptosis was increased. Finally, stable expression of STAT6 resulted in reduced foci formation compared to vector-transfected cells alone. These results suggest STAT6 is required for IL-4- mediated growth inhibition and induction of apoptosis in human breast cancer cells.

Original languageEnglish (US)
Pages (from-to)324-331
Number of pages8
JournalNeoplasia
Volume4
Issue number4
DOIs
StatePublished - Jan 1 2002

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Keywords

  • Apoptosis
  • Breast cancer
  • IL-4
  • Insulin receptor substrate
  • STAT6

ASJC Scopus subject areas

  • Cancer Research

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