Suppression of myeloid transcription factors and induction of STAT response genes by AML-specific Flt3 mutations

Blood. 2003 Apr 15;101(8):3164-73. doi: 10.1182/blood-2002-06-1677. Epub 2002 Dec 5.

Abstract

The receptor tyrosine kinase Flt3 is expressed and functionally important in early myeloid progenitor cells and in the majority of acute myeloid leukemia (AML) blasts. Internal tandem duplications (ITDs) in the juxtamembrane domain of the receptor occur in 25% of AML cases. Previously, we have shown that these mutations activate the receptor and induce leukemic transformation. In this study, we performed genome-wide parallel expression analyses of 32Dcl3 cells stably transfected with either wild-type or 3 different ITD isoforms of Flt3. Comparison of microarray expression analyses revealed that 767 of 6586 genes differed in expression between FLT3-WT- and FLT3-ITD-expressing cell lines. The target genes of mutationally activated Flt3 resembled more closely those of the interleukin 3 (IL-3) receptor than those of ligand-activated Flt3. The serine-threonine kinase Pim-2 was up-regulated on the mRNA and the protein level in Flt3-ITD-expressing cells. Further experiments indicated that Pim-2 function was important for clonal growth of 32D cells. Several genes repressed by the mutations were found to be involved in myeloid gene regulation. Pu.1 and C/EBPalpha, both induced by ligand-activation of wild-type Flt3, were suppressed in their expression and function by the Flt3 mutations. In conclusion, internal tandem duplication mutations of Flt3 activate transcriptional programs that partially mimic IL-3 activity. Interestingly, other parts of the transcriptional program involve novel, IL-3-independent pathways that antagonize differentiation-inducing effects of wild-type Flt3. The identification of the transcriptional program induced by ITD mutations should ease the development of specific therapies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Animals
  • CCAAT-Enhancer-Binding Protein-alpha / biosynthesis
  • CCAAT-Enhancer-Binding Protein-alpha / genetics
  • Cell Line / metabolism
  • Cluster Analysis
  • Computer Systems
  • Gene Expression Profiling
  • Gene Expression Regulation*
  • Gene Expression Regulation, Leukemic
  • Genes, Synthetic
  • Hematopoietic Stem Cells / metabolism
  • Humans
  • Interleukin-3 / pharmacology
  • Leukemia, Myeloid / genetics*
  • Leukemia, Myeloid / pathology
  • Mice
  • Myeloid Cells / metabolism
  • Neoplasm Proteins / biosynthesis
  • Neoplasm Proteins / genetics
  • Oligonucleotide Array Sequence Analysis
  • Protein Isoforms / physiology
  • Protein-Serine-Threonine Kinases*
  • Proto-Oncogene Proteins / biosynthesis
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / physiology*
  • Receptor Protein-Tyrosine Kinases / genetics
  • Receptor Protein-Tyrosine Kinases / physiology*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / physiology
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tandem Repeat Sequences*
  • Trans-Activators / biosynthesis
  • Trans-Activators / genetics
  • Transcription, Genetic*
  • Transfection
  • fms-Like Tyrosine Kinase 3

Substances

  • CCAAT-Enhancer-Binding Protein-alpha
  • Interleukin-3
  • Neoplasm Proteins
  • PIM2 protein, human
  • Pim2 protein, mouse
  • Protein Isoforms
  • Proto-Oncogene Proteins
  • Recombinant Fusion Proteins
  • Trans-Activators
  • proto-oncogene protein Spi-1
  • FLT3 protein, human
  • Flt3 protein, mouse
  • Receptor Protein-Tyrosine Kinases
  • fms-Like Tyrosine Kinase 3
  • Protein-Serine-Threonine Kinases