PKA phosphorylation redirects ERα to promoters of a unique gene set to induce tamoxifen resistance

Oncogene. 2013 Jul 25;32(30):3543-51. doi: 10.1038/onc.2012.361. Epub 2012 Aug 20.

Abstract

Protein kinase A (PKA)-induced estrogen receptor alpha (ERα) phosphorylation at serine residue 305 (ERαS305-P) can induce tamoxifen (TAM) resistance in breast cancer. How this phospho-modification affects ERα specificity and translates into TAM resistance is unclear. Here, we show that S305-P modification of ERα reprograms the receptor, redirecting it to new transcriptional start sites, thus modulating the transcriptome. By altering the chromatin-binding pattern, Ser305 phosphorylation of ERα translates into a 26-gene expression classifier that identifies breast cancer patients with a poor disease outcome after TAM treatment. MYC-target genes and networks were significantly enriched in this gene classifier that includes a number of selective targets for ERαS305-P. The enhanced expression of MYC increased cell proliferation in the presence of TAM. We demonstrate that activation of the PKA signaling pathway alters the transcriptome by redirecting ERα to new transcriptional start sites, resulting in altered transcription and TAM resistance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents, Hormonal / pharmacology*
  • Breast Neoplasms / drug therapy
  • Breast Neoplasms / genetics
  • Breast Neoplasms / pathology*
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • Drug Resistance, Neoplasm / genetics*
  • Estrogen Antagonists / pharmacology*
  • Estrogen Receptor alpha / metabolism*
  • Female
  • Gene Expression Regulation, Neoplastic / drug effects
  • Genes, Neoplasm* / drug effects
  • Humans
  • Phosphorylation
  • Promoter Regions, Genetic*
  • Protein Binding
  • Tamoxifen / pharmacology*

Substances

  • Antineoplastic Agents, Hormonal
  • Estrogen Antagonists
  • Estrogen Receptor alpha
  • estrogen receptor alpha, human
  • Tamoxifen
  • Cyclic AMP-Dependent Protein Kinases