Genome-wide screen reveals WNT11, a non-canonical WNT gene, as a direct target of ETS transcription factor ERG

Oncogene. 2011 Apr 28;30(17):2044-56. doi: 10.1038/onc.2010.582. Epub 2011 Jan 17.

Abstract

E26 transforming sequence-related gene (ERG) is a transcription factor involved in normal hematopoiesis and is dysregulated in leukemia. ERG mRNA overexpression was associated with poor prognosis in a subset of patients with T-cell acute lymphoblastic leukemia (T-ALL) and acute myeloid leukemia (AML). Herein, a genome-wide screen of ERG target genes was conducted by chromatin immunoprecipitation-on-chip (ChIP-chip) in Jurkat cells. In this screen, 342 significant annotated genes were derived from this global approach. Notably, ERG-enriched targets included WNT signaling genes: WNT11, WNT2, WNT9A, CCND1 and FZD7. Furthermore, chromatin immunoprecipitation (ChIP) of normal and primary leukemia bone marrow material also confirmed WNT11 as a target of ERG in six of seven patient samples. A larger sampling of patient diagnostic material revealed that ERG and WNT11 mRNA were co-expressed in 80% of AML (n=30) and 40% in T-ALL (n=30) bone marrow samples. Small interfering RNA (siRNA)-mediated knockdown of ERG confirmed downregulation of WNT11 transcripts. Conversely, in a tet-on ERG-inducible assay, WNT11 transcripts were co-stimulated. A WNT pathway agonist, 6-bromoindirubin-3-oxime (BIO), was used to determine the effect of cell growth on the ERG-inducible cells. The addition of BIO resulted in an ERG-dependent proliferative growth advantage over ERG-uninduced cells. Finally, ERG induction prompted morphological transformation whereby round unpolarized K562 cells developed elongated protrusions and became polarized. This morphological transformation could effectively be inhibited with BIO and with siRNA knockdown of WNT11. In conclusion, ERG transcriptional networks in leukemia converge on WNT signaling targets. Specifically, WNT11 emerged as a direct target of ERG. Potent ERG induction promoted morphological transformation through WNT11 signals. The findings in this study unravel new ERG-directed molecular signals that may contribute to the resistance of current therapies in acute leukemia patients with poor prognosis characterized by high ERG mRNA expression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Down-Regulation / genetics
  • Gene Knockdown Techniques
  • Genome, Human / genetics
  • Genomics*
  • Glycogen Synthase Kinase 3 / antagonists & inhibitors
  • Glycogen Synthase Kinase 3 beta
  • Humans
  • Indoles / pharmacology
  • Leukemia, Myelomonocytic, Acute / genetics
  • Oximes / pharmacology
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / genetics
  • Promoter Regions, Genetic / genetics
  • Protein Kinase Inhibitors / pharmacology
  • RNA, Small Interfering / genetics
  • Reproducibility of Results
  • Signal Transduction / drug effects
  • Trans-Activators / deficiency
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*
  • Transcriptional Regulator ERG
  • Up-Regulation / genetics
  • Wnt Proteins / agonists
  • Wnt Proteins / deficiency
  • Wnt Proteins / genetics*
  • Wnt Proteins / metabolism

Substances

  • 6-bromoindirubin-3'-oxime
  • ERG protein, human
  • Indoles
  • Oximes
  • Protein Kinase Inhibitors
  • RNA, Small Interfering
  • Trans-Activators
  • Transcriptional Regulator ERG
  • Wnt Proteins
  • Wnt11 protein, human
  • Glycogen Synthase Kinase 3 beta
  • Glycogen Synthase Kinase 3