AML1-MTG8 leukemic protein induces the expression of granulocyte colony-stimulating factor (G-CSF) receptor through the up-regulation of CCAAT/enhancer binding protein epsilon.
The t(8;21) translocation is one of the most frequent chromosomal abnormalities associated with acute myeloid leukemia (AML). In this translocation, the AML1 (CBFA2/PEBP2aB) gene is disrupted and fused to the MTG8 (ETO) gene. The ectopic expression of the resulting AML1-MTG8 fusion gene product in L-G and 32Dcl3 murine myeloid precursor cells stimulates cell proliferation without inducing morphologic terminal differentiation into mature granulocytes in response to granulocyte-colony stimulating factor (G-CSF). This study found that the ectopic expression of AML1-MTG8 elevates the expression of the G-CSF receptor (G-CSFR). Analysis of the promoter region of the G-CSFR gene revealed that up-regulation of G-CSFR expression by AML1-MTG8 does not depend on the AML1-binding sequence, but on the C/EBP (CCAAT/enhancer binding protein) binding site. The results suggest that the overproduction of G-CSFR is at least partly mediated by C/EBPepsilon, whose expression is activated by AML1-MTG8. The ectopic expression of G-CSFR in L-G cells induced cell proliferation in response to G-CSF, but did not inhibit cell differentiation into mature neutrophils. Overexpression of C/EBPepsilon in L-G cells also stimulated G-CSF-dependent cell proliferation. High expression levels of G-CSFR were also found in the leukemic cells of AML patients with t(8;21). Therefore, G-CSF-dependent cell proliferation of myeloid precursor cells may be implicated in leukemogenesis.
Shimizu
K
K
Radiobiology Division, National Cancer Center Research Institute, Tsukiji, Chuo-ku, Tokyo 104-0045, Japan. kkikuchi@ncc.go.jp
Kitabayashi
I
I
Kamada
N
N
Abe
T
T
Maseki
N
N
Suzukawa
K
K
Ohki
M
M
D000818:Animals; D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D050676:Core Binding Factor Alpha 2 Subunit; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D007951:Leukemia, Myeloid / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D015514:Oncogene Proteins, Fusion / Q000235:genetics* / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D000075142:RUNX1 Translocation Partner 1 Protein; D016188:Receptors, Granulocyte Colony-Stimulating Factor / Q000235:genetics*; D011994:Recombinant Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D014178:Translocation, Genetic
C107844:AML1-ETO fusion protein, human; D022762:CCAAT-Enhancer-Binding Proteins; D050676:Core Binding Factor Alpha 2 Subunit; D017931:DNA Primers; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D015514:Oncogene Proteins, Fusion; D000075142:RUNX1 Translocation Partner 1 Protein; D016188:Receptors, Granulocyte Colony-Stimulating Factor; D011994:Recombinant Proteins; D014157:Transcription Factors; D016179:Granulocyte Colony-Stimulating Factor