Enforced expression of NUP98-HOXA9 in human CD34(+) cells enhances stem cell proliferation.
The t(7;11)(p15;p15) translocation, observed in acute myelogenous leukemia and myelodysplastic syndrome, generates a chimeric gene where the 5' portion of the sequence encoding the human nucleoporin NUP98 protein is fused to the 3' region of HOXA9. Here, we show that retroviral-mediated enforced expression of the NUP98-HOXA9 fusion protein in cord blood-derived CD34(+) cells confers a proliferative advantage in both cytokine-stimulated suspension cultures and stromal coculture. This advantage is reflected in the selective expansion of hematopoietic stem cells as measured in vitro by cobblestone area-forming cell assays and in vivo by competitive repopulation of nonobese diabetic/severe combined immunodeficient mice. NUP98-HOXA9 expression inhibited erythroid progenitor differentiation and delayed neutrophil maturation in transduced progenitors but strongly enhanced their serial replating efficiency. Analysis of the transcriptosome of transduced cells revealed up-regulation of several homeobox genes of the A and B cluster as well as of Meis1 and Pim-1 and down-modulation of globin genes and of CAAT/enhancer binding protein alpha. The latter gene, when coexpressed with NUP98-HOXA9, reversed the enhanced proliferation of transduced CD34(+) cells. Unlike HOXA9, the NUP98-HOXA9 fusion was protected from ubiquitination mediated by Cullin-4A and subsequent proteasome-dependent degradation. The resulting protein stabilization may contribute to the leukemogenic activity of the fusion protein.
Chung
Ki Y
KY
Department of Medicine and Moore Laboratory, Cell Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Morrone
Giovanni
G
Schuringa
Jan Jacob
JJ
Plasilova
Magdalena
M
Shieh
Jae-Hung
JH
Zhang
Yue
Y
Zhou
Pengbo
P
Moore
Malcolm A S
MA
D015703:Antigens, CD / Q000502:physiology; D018952:Antigens, CD34 / Q000502:physiology*; D002455:Cell Division; D002460:Cell Line; D002874:Chromosome Mapping; D002880:Chromosomes, Human, Pair 11; D002897:Chromosomes, Human, Pair 7; D003001:Cloning, Molecular; D003114:Colony-Forming Units Assay; D005312:Fetal Blood; D050939:Gene Fusion; D005822:Genetic Vectors; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D050506:Mutant Chimeric Proteins / Q000235:genetics*; D028861:Nuclear Pore Complex Proteins / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D012190:Retroviridae / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology*; D014178:Translocation, Genetic; D014470:Umbilical Cord
D015703:Antigens, CD; D018952:Antigens, CD34; D018398:Homeodomain Proteins; D050506:Mutant Chimeric Proteins; D028861:Nuclear Pore Complex Proteins; C465451:Nup98 protein, human; C097899:homeobox protein HOXA9