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Clin Cancer Res. 2019 Oct 1;25(19):5901-5912. doi: 10.1158/1078-0432.CCR-18-4089. Epub 2019 Jun 19.

Activation of JAK/STAT Signaling in Megakaryocytes Sustains Myeloproliferation In Vivo.

Author information

1
Human Oncology and Pathogenesis Program, Center for Hematologic Malignancies and Leukemia Service, Memorial Sloan Kettering Cancer Center, New York, New York.
2
Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York.
3
Blood Disease Institute, Xuzhou Medical University, Xuzhou, China.
4
Division of Hematology/Oncology, Northwestern University, Chicago, Illinois.
5
Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing, China.
6
Division of Hematology/Oncology, Northwestern University, Chicago, Illinois. q-wen@northwestern.edu.

Abstract

PURPOSE:

The myeloproliferative neoplasms (MPN), including polycythemia vera, essential thrombocythemia, and primary myelofibrosis, are characterized by the expansion of the erythroid, megakaryocytic, and granulocytic lineages. A common feature of these disorders is the presence of abnormal megakaryocytes, which have been implicated as causative agents in the development of bone marrow fibrosis. However, the specific contributions of megakaryocytes to MPN pathogenesis remain unclear.

EXPERIMENTAL DESIGN:

We used Pf4-Cre transgenic mice to drive expression of JAK2V617F in megakaryocyte lineage-committed hematopoietic cells. We also assessed the critical role of mutant megakaryocytes in MPN maintenance through cell ablation studies in JAK2V617F and MPLW515L BMT models of MPN.

RESULTS:

JAK2V617F -mutant presence in megakaryocytes was sufficient to induce enhanced erythropoiesis and promote fibrosis, which leads to a myeloproliferative state with expansion of mutant and nonmutant hematopoietic cells. The increased erythropoiesis was associated with elevated IL6 level, which was also required for aberrant erythropoiesis in vivo. Furthermore, depletion of megakaryocytes in the JAK2V617F and MPLW515L BMT models ameliorated polycythemia and leukocytosis in addition to expected effects on megakaryopoiesis.

CONCLUSIONS:

Our observations reveal that JAK/STAT pathway activation in megakaryocytes induces myeloproliferation and is necessary for MPN maintenance in vivo. These observations indicate that MPN clone can influence the behavior of the wild-type hematopoietic milieu, at least, in part, via altered production of proinflammatory cytokines and chemokines. Our findings resonate with patients who present with a clinical MPN and a low JAK2V617F allele burden, and support the development of MPN therapies aimed at targeting megakaryocytes.

PMID:
31217200
PMCID:
PMC6774846
[Available on 2020-04-01]
DOI:
10.1158/1078-0432.CCR-18-4089

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