The JAK2 V617F mutation occurs in hematopoietic stem cells in polycythemia vera and predisposes toward erythroid differentiation

doi:10.1073/pnas.0601462103

The JAK2 V617F mutation occurs in hematopoietic stem cells in polycythemia vera and predisposes toward erythroid differentiation

*Department of Medicine and Moores Cancer Center, University of California at San Diego, La Jolla, CA 92093;
^†Departments of Medicine and
^§Pathology, and
^¶Institute for Stem Cell Biology and Regenerative Medicine and Comprehensive Cancer Center, Stanford University School of Medicine, Stanford, CA 94305; and
^‡Transgenomic, Inc., Gaithersburg, MD 20878

Contributed by Irving L. Weissman, February 27, 2006

Abstract

Although a large proportion of patients with polycythemia vera (PV) harbor a valine-to-phenylalanine mutation at amino acid 617 (V617F) in the JAK2 signaling molecule, the stage of hematopoiesis at which the mutation arises is unknown. Here we isolated and characterized hematopoietic stem cells (HSC) and myeloid progenitors from 16 PV patient samples and 14 normal individuals, testing whether the JAK2 mutation could be found at the level of stem or progenitor cells and whether the JAK2 V617F-positive cells had altered differentiation potential. In all PV samples analyzed, there were increased numbers of cells with a HSC phenotype (CD34⁺CD38⁻CD90⁺Lin⁻) compared with normal samples. Hematopoietic progenitor assays demonstrated that the differentiation potential of PV was already skewed toward the erythroid lineage at the HSC level. The JAK2 V617F mutation was detectable within HSC and their progeny in PV. Moreover, the aberrant erythroid potential of PV HSC was potently inhibited with a JAK2 inhibitor, AG490.

Footnotes

^‖To whom correspondence should be addressed at:
Department of Pathology, 279 Campus Drive West, B257 Beckman Center, Stanford University School of Medicine, Stanford, CA 94305-5323.
E-mail: irv{at}stanford.edu
Author contributions: C.H.M.J., J.G., J.A.D., M.R.M., M.L., C.J., J.L.Z., S.L.L., and I.L.W. designed research; C.H.M.J., J.G., J.A.D., M.P.C., M.R.M., M.L., C.J., J.L.Z., and I.L.W. performed research; C.H.M.J., J.G., J.A.D., M.P.C., M.R.M., M.L., C.J., J.L.Z., S.L.L., and I.L.W. contributed new reagents/analytic tools; C.H.M.J., J.G., J.A.D., M.P.C., M.R.M., M.L., C.J., J.L.Z., S.L.L., and I.L.W. analyzed data; and C.H.M.J., J.G., J.A.D., M.R.M., C.J., J.L.Z., S.L.L., and I.L.W. wrote the paper.
Conflict of interest statement: C.H.M.J. and I.L.W. have applied for U.S. patents entitled “Methods of Identifying and Isolating Stem Cells and Cancer Stem Cells” and “Methods of Diagnosing and Evaluating Blood Disorders” through the Stanford University Office of Technology and Licensing. I.L.W. receives consulting fees from and has equity ownership in Cellerant Therapeutics (San Carlos, CA).
Abbreviations:

Abbreviations:

HSC,

hematopoietic stem cell;

CMP,

common myeloid progenitor;

GMP,

granulocyte/macrophage progenitor;

MEP,

megakaryocyte/erythrocyte progenitor;

PV,

polycythemia vera;

MPD,

myeloproliferative disorder;

JAK2 V617F,

Janus kinase 2 valine-to-phenylalanine mutation at amino acid 617;

CFU,

colony-forming unit;

BFU,

burst-forming unit;

BFU-E,

BFU-erythroid;

CFU-G,

CFU-granulocyte;

CFU-M,

CFU-macrophage;

CFU-Mix,

mixed colonies composed of granulocytes, erythrocytes, megakaryocytes, and macrophages;

CFU-Mega,

CFU-megakaryocyte;

CFU-GM,

CFU-granulocyte/macrophage.
Freely available online through the PNAS open access option.