NUP98-HOXA9 induces long-term proliferation and blocks differentiation of primary human CD34+ hematopoietic cells.
NUP98-HOXA9, the chimeric protein resulting from the t(7;11)(p15;p15) chromosomal translocation, is a prototype of several NUP98 fusions that occur in myelodysplastic syndromes and acute myeloid leukemia. We examined its effect on differentiation, proliferation, and gene expression in primary human CD34+ hematopoietic cells. Colony-forming cell (CFC) assays in semisolid medium combined with morphologic examination and flow cytometric immunophenotyping revealed that NUP98-HOXA9 increased the numbers of erythroid precursors and impaired both myeloid and erythroid differentiation. In continuous liquid culture, cells transduced with NUP98-HOXA9 exhibited a biphasic growth curve with initial growth inhibition followed by enhanced long-term proliferation, suggesting an increase in the numbers of primitive self-renewing cells. This was confirmed by a dramatic increase in the numbers of long-term culture-initiating cells, the most primitive hematopoietic cells detectable in vitro. To understand the molecular mechanisms underlying the effects of NUP98-HOXA9 on hematopoietic cell proliferation and differentiation, oligonucleotide microarray analysis was done at several time points over 16 days, starting at 6 hours posttransduction. The early growth suppression was preceded by up-regulation of IFNbeta1 and accompanied by marked up-regulation of IFN-induced genes, peaking at 3 days posttransduction. In contrast, oncogenes such as homeobox transcription factors, FLT3, KIT, and WT1 peaked at 8 days or beyond, coinciding with increased proliferation. In addition, several putative tumor suppressors and genes associated with hematopoietic differentiation were repressed at later time points. These findings provide a comprehensive picture of the changes in proliferation, differentiation, and global gene expression that underlie the leukemic transformation of human hematopoietic cells by NUP98-HOXA9.
Takeda
Akiko
A
Department of Pathology, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Chicago, IL 60611, USA.
Goolsby
Charles
C
Yaseen
Nabeel R
NR
D018952:Antigens, CD34 / Q000096:biosynthesis*; D002454:Cell Differentiation / Q000502:physiology; D048708:Cell Growth Processes / Q000502:physiology; D041905:Erythroid Cells / Q000166:cytology / Q000378:metabolism; D015870:Gene Expression; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D018398:Homeodomain Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D006801:Humans; D016899:Interferon-beta / Q000235:genetics; D022423:Myeloid Cells / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D028861:Nuclear Pore Complex Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D015514:Oncogene Proteins, Fusion / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D012190:Retroviridae / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D014161:Transduction, Genetic
D018952:Antigens, CD34; D018398:Homeodomain Proteins; C400441:NUP98-HOXA9 fusion protein, human; D028861:Nuclear Pore Complex Proteins; D015514:Oncogene Proteins, Fusion; D014157:Transcription Factors; D016899:Interferon-beta