RARalpha-PLZF overcomes PLZF-mediated repression of CRABPI, contributing to retinoid resistance in t(11;17) acute promyelocytic leukemia

Proc Natl Acad Sci U S A. 2007 Nov 20;104(47):18694-9. doi: 10.1073/pnas.0704433104. Epub 2007 Nov 13.

Abstract

Leukemia-associated chimeric oncoproteins often act as transcriptional repressors, targeting promoters of master genes involved in hematopoiesis. We show that CRABPI (encoding cellular retinoic acid binding protein I) is a target of PLZF, which is fused to RARalpha by the t(11;17)(q23;q21) translocation associated with retinoic acid (RA)-resistant acute promyelocytic leukemia (APL). PLZF represses the CRABPI locus through propagation of chromatin condensation from a remote intronic binding element culminating in silencing of the promoter. Although the canonical, PLZF-RARalpha oncoprotein has no impact on PLZF-mediated repression, the reciprocal translocation product RARalpha-PLZF binds to this remote binding site, recruiting p300, inducing promoter hypomethylation and CRABPI gene up-regulation. In line with these observations, RA-resistant murine PLZF/RARalpha+RARalpha/PLZF APL blasts express much higher levels of CRABPI than standard RA-sensitive PML/RARalpha APL. RARalpha-PLZF confers RA resistance to a retinoid-sensitive acute myeloid leukemia (AML) cell line in a CRABPI-dependent fashion. This study supports an active role for PLZF and RARalpha-PLZF in leukemogenesis, identifies up-regulation of CRABPI as a mechanism contributing to retinoid resistance, and reveals the ability of the reciprocal fusion gene products to mediate distinct epigenetic effects contributing to the leukemic phenotype.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Binding Sites
  • Cell Line
  • Chromatin / genetics
  • Chromosomes, Human, Pair 11 / genetics*
  • Chromosomes, Human, Pair 17 / genetics*
  • DNA Methylation
  • Disease Progression
  • Drug Resistance, Neoplasm / drug effects
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Kruppel-Like Transcription Factors / metabolism*
  • Leukemia, Promyelocytic, Acute / genetics*
  • Leukemia, Promyelocytic, Acute / metabolism*
  • Leukemia, Promyelocytic, Acute / pathology
  • Molecular Sequence Data
  • Promyelocytic Leukemia Zinc Finger Protein
  • Receptors, Retinoic Acid / genetics
  • Receptors, Retinoic Acid / metabolism*
  • Retinoic Acid Receptor alpha
  • Retinoids / pharmacology
  • Up-Regulation

Substances

  • Chromatin
  • Kruppel-Like Transcription Factors
  • Promyelocytic Leukemia Zinc Finger Protein
  • RARA protein, human
  • Receptors, Retinoic Acid
  • Retinoic Acid Receptor alpha
  • Retinoids
  • retinoic acid binding protein I, cellular
  • ZBTB16 protein, human

Associated data

  • GEO/GSE8510