JAK2T875N is a novel activating mutation that results in myeloproliferative disease with features of megakaryoblastic leukemia in a murine bone marrow transplantation model.
Acute megakaryoblastic leukemia (AMKL) is a subtype of acute myeloid leukemia associated with a poor prognosis. However, there are relatively few insights into the genetic etiology of AMKL. We developed a screening assay for mutations that cause AMKL, based on the hypothesis that constitutive activation of STAT5 would be a biochemical indicator of mutation in an upstream effector tyrosine kinase. We screened human AMKL cell lines for constitutive STAT5 activation, and then used an approach combining mass spectrometry identification of tyrosine phosphorylated proteins and growth inhibition in the presence of selective small molecule tyrosine kinase inhibitors that would inform DNA sequence analysis of candidate tyrosine kinases. Using this strategy, we identified a new JAK2T875N mutation in the AMKL cell line CHRF-288-11. JAK2T875N is a constitutively activated tyrosine kinase that activates downstream effectors including STAT5 in hematopoietic cells in vitro. In a murine transplant model, JAK2T875N induced a myeloproliferative disease characterized by features of AMKL, including megakaryocytic hyperplasia in the spleen; impaired megakaryocyte polyploidization; and increased reticulin fibrosis of the bone marrow and spleen. These findings provide new insights into pathways and therapeutic targets that contribute to the pathogenesis of AMKL.
Mercher
Thomas
T
Division of Hematology, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Wernig
Gerlinde
G
Moore
Sandra A
SA
Levine
Ross L
RL
Gu
Ting-Lei
TL
Fröhling
Stefan
S
Cullen
Dana
D
Polakiewicz
Roberto D
RD
Bernard
Olivier A
OA
Boggon
Titus J
TJ
Lee
Benjamin H
BH
Gilliland
D Gary
DG
D000818:Animals; D016026:Bone Marrow Transplantation; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D003114:Colony-Forming Units Assay; D004789:Enzyme Activation; D006801:Humans; D016130:Immunophenotyping; D053614:Janus Kinase 2; D020014:K562 Cells; D007947:Leukemia, Megakaryoblastic, Acute / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008958:Models, Molecular; D009154:Mutation; D009196:Myeloproliferative Disorders / Q000201:enzymology* / Q000209:etiology / Q000235:genetics* / Q000473:pathology; D010766:Phosphorylation; D011487:Protein Conformation; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D050799:STAT5 Transcription Factor / Q000378:metabolism; D014161:Transduction, Genetic
D011518:Proto-Oncogene Proteins; D050799:STAT5 Transcription Factor; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; C507926:Jak2 protein, mouse; D053614:Janus Kinase 2