CD34+ cells from AML with mutated NPM1 harbor cytoplasmic mutated nucleophosmin and generate leukemia in immunocompromised mice.
Acute myeloid leukemia (AML) with mutated NPM1 shows distinctive biologic and clinical features, including absent/low CD34 expression, the significance of which remains unclear. Therefore, we analyzed CD34(+) cells from 41 NPM1-mutated AML. At flow cytometry, 31 of 41 samples contained less than 10% cells showing low intensity CD34 positivity and variable expression of CD38. Mutational analysis and/or Western blotting of purified CD34(+) cells from 17 patients revealed NPM1-mutated gene and/or protein in all. Immunohistochemistry of trephine bone marrow biopsies and/or flow cytometry proved CD34(+) leukemia cells from NPM1-mutated AML had aberrant nucleophosmin expression in cytoplasm. NPM1-mutated gene and/or protein was also confirmed in a CD34(+) subfraction exhibiting the phenotype (CD34(+)/CD38(-)/CD123(+)/CD33(+)/CD90(-)) of leukemic stem cells. When transplanted into immunocompromised mice, CD34(+) cells generated a leukemia recapitulating, both morphologically and immunohistochemically (aberrant cytoplasmic nucleophosmin, CD34 negativity), the original patient's disease. These results indicate that the CD34(+) fraction in NPM1-mutated AML belongs to the leukemic clone and contains NPM1-mutated cells exhibiting properties typical of leukemia-initiating cells. CD34(-) cells from few cases (2/15) also showed significant leukemia-initiating cell potential in immunocompromised mice. This study provides further evidence that NPM1 mutation is a founder genetic lesion and has potential implications for the cell-of-origin and targeted therapy of NPM1-mutated AML.
Martelli
Maria Paola
MP
Institute of Hematology and Clinical Immunology, University of Perugia, Perugia, Italy.
Pettirossi
Valentina
V
Thiede
Christian
C
Bonifacio
Elisabetta
E
Mezzasoma
Federica
F
Cecchini
Debora
D
Pacini
Roberta
R
Tabarrini
Alessia
A
Ciurnelli
Raffaella
R
Gionfriddo
Ilaria
I
Manes
Nicla
N
Rossi
Roberta
R
Giunchi
Linda
L
Oelschlägel
Uta
U
Brunetti
Lorenzo
L
Gemei
Marica
M
Delia
Mario
M
Specchia
Giorgina
G
Liso
Arcangelo
A
Di Ianni
Mauro
M
Di Raimondo
Francesco
F
Falzetti
Franca
F
Del Vecchio
Luigi
L
Martelli
Massimo F
MF
Falini
Brunangelo
B
D051997:ADP-ribosyl Cyclase 1 / Q000378:metabolism; D000818:Animals; D018952:Antigens, CD34 / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D016130:Immunophenotyping; D015470:Leukemia, Myeloid, Acute / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D050505:Mutant Proteins / Q000235:genetics* / Q000378:metabolism; D009368:Neoplasm Transplantation; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D000090243:Nucleophosmin; D014183:Transplantation, Heterologous
D018952:Antigens, CD34; D008562:Membrane Glycoproteins; D050505:Mutant Proteins; C000716967:NPM1 protein, human; C000715570:Npm1 protein, mouse; D009687:Nuclear Proteins; D000090243:Nucleophosmin; C498154:CD38 protein, human; D051997:ADP-ribosyl Cyclase 1