AML1/ETO-induced survivin expression inhibits transcriptional regulation of myeloid differentiation.
OBJECTIVE
The (8;21)(q22;q22) chromosomal translocation, which involves AML1 gene on chromosome 21 and the ETO gene on chromosome 8, generates an AML1/ETO fusion. AML1/ETO is associated with 15% of acute myeloid leukemia (AML) cases. The fusion gene is a dominant inhibitor of myeloid-specific genes, notably AML1, CCAAT/enhancer-binding protein-alpha (C/EBPalpha), and myeloperoxidase (MPO). In this study, we investigated the role of antiapoptosis gene survivin as a target of AML1/ETO-related leukemia.


METHODS
Through the combination of reporter assays, electrophoretic mobility shift assay, quantitative real-time polymerase chain reaction analysis, and short hairpin RNA (shRNA)-mediated knockdown of genes, we showed that survivin is a critical target of AML1/ETO. Biological studies were performed in cell lines and primary human CD 34(+) cells.


RESULTS
In this study, we have shown that ectopic expression of AML1/ETO induces survivin gene expression in both a cell line model and in the primary human hematopoietic CD34(+) cells. Reporter assays demonstrate that ectopically expressed AML1/ETO activates survivin promoter. Endogenous AML1/ETO derived from the Kasumi-1 cell line nuclear extract binds physically to the AML1 core enhancer-binding sequence, TGTGGT, derived from the survivin promotor. Knockdown of survivin expression by shRNA in ectopically expressed AML1/ETO myeloid leukemia cell lines restores expression of C/EBPalpha, granulocyte colony-stimulating factor receptor, and MPO genes, which leads to their growth arrest and granulocytic differentiation.


CONCLUSIONS
Our results demonstrate that survivin gene acts as a critical mediator of AML1/ETO-induced late oncogeneic events.
Balkhi
Mumtaz Yaseen
MY
Bone Marrow Transplantation Unit, State Centre for Cell and Gene Therapy, Clinic Internal Medicine IV, Martin-Luther-University, Halle, Germany.
Christopeit
Maximilian
M
Chen
Yong
Y
Geletu
Mulu
M
Behre
Gerhard
G
D001483:Base Sequence; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000502:physiology; D002454:Cell Differentiation; D050676:Core Binding Factor Alpha 2 Subunit / Q000502:physiology*; D006098:Granulocytes / Q000166:cytology*; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics*; D015514:Oncogene Proteins, Fusion / Q000502:physiology*; D011401:Promoter Regions, Genetic; D034741:RNA, Small Interfering / Q000494:pharmacology; D000075142:RUNX1 Translocation Partner 1 Protein; D000077022:Survivin; D014158:Transcription, Genetic
C107844:AML1-ETO fusion protein, human; C107489:BIRC5 protein, human; D022763:CCAAT-Enhancer-Binding Protein-alpha; D050676:Core Binding Factor Alpha 2 Subunit; D051034:Inhibitor of Apoptosis Proteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D015514:Oncogene Proteins, Fusion; D034741:RNA, Small Interfering; D000075142:RUNX1 Translocation Partner 1 Protein; D000077022:Survivin