Suppression of myeloid transcription factors and induction of STAT response genes by AML-specific Flt3 mutations.
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.
Mizuki
Masao
M
Department of Medicine, Hematology/Oncology, University of Münster, Germany.
Schwable
Joachim
J
Steur
Claudia
C
Choudhary
Chunaram
C
Agrawal
Shuchi
S
Sargin
Bülent
B
Steffen
Björn
B
Matsumura
Itaru
I
Kanakura
Yuzuru
Y
Böhmer
Frank D
FD
Müller-Tidow
Carsten
C
Berdel
Wolfgang E
WE
Serve
Hubert
H
D000208:Acute Disease; D000818:Animals; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000096:biosynthesis / Q000235:genetics; D002460:Cell Line / Q000378:metabolism; D016000:Cluster Analysis; D003199:Computer Systems; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D015973:Gene Expression Regulation, Leukemic; D005813:Genes, Synthetic; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D007951:Leukemia, Myeloid / Q000235:genetics* / Q000473:pathology; D051379:Mice; D022423:Myeloid Cells / Q000378:metabolism; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D020033:Protein Isoforms / Q000502:physiology; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020080:Tandem Repeat Sequences; D015534:Trans-Activators / Q000096:biosynthesis / Q000235:genetics; D014158:Transcription, Genetic; D014162:Transfection; D051941:fms-Like Tyrosine Kinase 3; D000099232:Proto-Oncogene Protein Spi-1
D022763:CCAAT-Enhancer-Binding Protein-alpha; D007377:Interleukin-3; D009363:Neoplasm Proteins; D020033:Protein Isoforms; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D020794:Receptor Protein-Tyrosine Kinases; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D051941:fms-Like Tyrosine Kinase 3; D000099232:Proto-Oncogene Protein Spi-1; C490587:PIM2 protein, human; C094167:Pim2 protein, mouse; C497970:FLT3 protein, human; C497971:Flt3 protein, mouse