STAT5 requires the N-domain for suppression of miR15/16, induction of bcl-2, and survival signaling in myeloproliferative disease

Blood. 2010 Feb 18;115(7):1416-24. doi: 10.1182/blood-2009-07-234963. Epub 2009 Dec 14.

Abstract

Phosphorylated signal transducer and activator of transcription 5 (STAT5) is a biomarker and potential molecular target for hematologic malignancies. We have shown previously that lethal myeloproliferative disease (MPD) in mice mediated by persistently activated STAT5 (STAT5a(S711F)) requires the N-domain, but the mechanism was not defined. We now demonstrate by retrovirally complementing STAT5ab(null/null) primary mast cells that relative to wild-type STAT5a, STAT5a lacking the N-domain (STAT5aDeltaN) ineffectively protected against cytokine withdrawal-induced cell death. Both STAT5a and STAT5aDeltaN bound to a site in the bcl-2 gene and both bound near the microRNA 15b/16 cluster. However, only STAT5a could effectively induce bcl-2 mRNA and reciprocally suppress miR15b/16 leading to maintained bcl-2 protein levels. After retroviral complementation of STAT5ab(null/null) fetal liver cells and transplantation, persistently active STAT5a(S711F) lacking the N-domain (STAT5aDeltaN(S711F)) was insufficient to protect c-Kit(+)Lin(-)Sca-1(+) (KLS) cells from apoptosis and unable to induce bcl-2 expression, whereas STAT5a(S711F) caused robust KLS cell expansion, induction of bcl-2, and lethal MPD. Severe attenuation of MPD by STAT5aDeltaN(S711F) was reversed by H2k/bcl-2 transgenic expression. Overall, these studies define N-domain-dependent survival signaling as an Achilles heel of persistent STAT5 activation and highlight the potential therapeutic importance of targeting STAT5 N-domain-mediated regulation of bcl-2 family members.

Publication types

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

MeSH terms

  • Animals
  • Cell Survival / physiology
  • Gene Expression Regulation, Neoplastic
  • Hematopoietic Stem Cells / pathology
  • Hematopoietic Stem Cells / physiology
  • Introns / physiology
  • Membrane Proteins / physiology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • MicroRNAs / metabolism*
  • Morphinans / metabolism
  • Myeloproliferative Disorders / metabolism
  • Myeloproliferative Disorders / pathology
  • Myeloproliferative Disorders / physiopathology*
  • Protein Structure, Tertiary
  • Proto-Oncogene Proteins c-bcl-2 / genetics*
  • RNA Processing, Post-Transcriptional / physiology
  • STAT5 Transcription Factor / chemistry
  • STAT5 Transcription Factor / genetics*
  • STAT5 Transcription Factor / metabolism
  • Signal Transduction / physiology

Substances

  • Atp5md protein, rat
  • Membrane Proteins
  • MicroRNAs
  • Mirn15a microRNA, mouse
  • Mirn16 microRNA, mouse
  • Morphinans
  • Proto-Oncogene Proteins c-bcl-2
  • STAT5 Transcription Factor
  • Stat5a protein, mouse
  • Stat5b protein, mouse
  • Mr 1257 MS