Comprehensive genomic screens identify a role for PLZF-RARalpha as a positive regulator of cell proliferation via direct regulation of c-MYC

Blood. 2009 Dec 24;114(27):5499-511. doi: 10.1182/blood-2009-03-206524. Epub 2009 Oct 23.

Abstract

The t(11;17)(q23;q21) translocation is associated with a retinoic acid (RA)-insensitive form of acute promyelocytic leukemia (APL), involving the production of reciprocal fusion proteins, promyelocytic leukemia zinc finger-retinoic acid receptor alpha (PLZF-RARalpha) and RARalpha-PLZF. Using a combination of chromatin immunoprecipitation promotor arrays (ChIP-chip) and gene expression profiling, we identify novel, direct target genes of PLZF-RARalpha that tend to be repressed in APL compared with other myeloid leukemias, supporting the role of PLZF-RARalpha as an aberrant repressor in APL. In primary murine hematopoietic progenitors, PLZF-RARalpha promotes cell growth, and represses Dusp6 and Cdkn2d, while inducing c-Myc expression, consistent with its role in leukemogenesis. PLZF-RARalpha binds to a region of the c-MYC promoter overlapping a functional PLZF site and antagonizes PLZF-mediated repression, suggesting that PLZF-RARalpha may act as a dominant-negative version of PLZF by affecting the regulation of shared targets. RA induced the differentiation of PLZF-RARalpha-transformed murine hematopoietic cells and reduced the frequency of clonogenic progenitors, concomitant with c-Myc down-regulation. Surviving RA-treated cells retained the ability to be replated and this was associated with sustained c-Myc expression and repression of Dusp6, suggesting a role for these genes in maintaining a self-renewal pathway triggered by PLZF-RARalpha.

Publication types

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

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology
  • Cell Proliferation*
  • Cell Survival / drug effects
  • Cell Survival / genetics
  • Cell Survival / physiology
  • Chromatin Immunoprecipitation
  • Cyclin-Dependent Kinase Inhibitor p19 / genetics
  • Cyclin-Dependent Kinase Inhibitor p19 / metabolism
  • Dual Specificity Phosphatase 6 / genetics
  • Dual Specificity Phosphatase 6 / metabolism
  • Gene Expression Profiling
  • Gene Expression Regulation, Leukemic / drug effects
  • Genome, Human / genetics*
  • Genome-Wide Association Study
  • Hematopoietic Stem Cells / cytology
  • Hematopoietic Stem Cells / metabolism
  • Humans
  • Leukemia, Promyelocytic, Acute / genetics
  • Leukemia, Promyelocytic, Acute / metabolism
  • Leukemia, Promyelocytic, Acute / pathology
  • Mice
  • Oligonucleotide Array Sequence Analysis
  • Oncogene Proteins, Fusion / genetics*
  • Oncogene Proteins, Fusion / metabolism
  • Oncogene Proteins, Fusion / physiology
  • Protein Binding
  • Proto-Oncogene Proteins c-myc / genetics*
  • Proto-Oncogene Proteins c-myc / metabolism
  • Tretinoin / pharmacology
  • U937 Cells
  • Xenograft Model Antitumor Assays

Substances

  • Antineoplastic Agents
  • Cdkn2d protein, mouse
  • Cyclin-Dependent Kinase Inhibitor p19
  • Oncogene Proteins, Fusion
  • PLZF-RARalpha fusion protein, human
  • PLZF-RARalpha fusion protein, mouse
  • Proto-Oncogene Proteins c-myc
  • Tretinoin
  • Dual Specificity Phosphatase 6
  • Dusp6 protein, mouse