Proliferation and survival signaling from both Jak2-V617F and Lyn involving GSK3 and mTOR/p70S6K/4EBP1 in PVTL-1 cell line newly established from acute myeloid leukemia transformed from polycythemia vera

PLoS One. 2014 Jan 3;9(1):e84746. doi: 10.1371/journal.pone.0084746. eCollection 2014.

Abstract

The gain of function mutation JAK2-V617F is very frequently found in myeloproliferative neoplasms (MPNs) and is strongly implicated in pathogenesis of these and other hematological malignancies. Here we report establishment of a new leukemia cell line, PVTL-1, homozygous for JAK2-V617F from a 73-year-old female patient with acute myeloid leukemia (AML) transformed from MPN. PVTL-1 is positive for CD7, CD13, CD33, CD34, CD117, HLA-DR, and MPO, and has complex karyotypic abnormalities, 44,XX,-5q,-7,-8,add(11)(p11.2),add(11)(q23),-16,+21,-22,+mar1. Sequence analysis of JAK2 revealed only the mutated allele coding for Jak2-V617F. Proliferation of PVTL-1 was inhibited and apoptosis was induced by the pan-Jak inhibitor Jak inhibitor-1 (JakI-1) or dasatinib, which inhibits the Src family kinases as well as BCR/ABL. Consistently, the Src family kinase Lyn was constitutively activated with phosphorylation of Y396 in the activation loop, which was inhibited by dasatinib but not by JakI-1. Further analyses with JakI-1 and dasatinib indicated that Jak2-V617F phosphorylated STAT5 and SHP2 while Lyn phosphorylated SHP1, SHP2, Gab-2, c-Cbl, and CrkL to induce the SHP2/Gab2 and c-Cbl/CrkL complex formation. In addition, JakI-1 and dasatinib inactivated the mTOR/p70S6K/4EBP1 pathway and reduced the inhibitory phosphorylation of GSK3 in PVTL-1 cells, which correlated with their effects on proliferation and survival of these cells. Furthermore, inhibition of GSK3 by its inhibitor SB216763 mitigated apoptosis induced by dasatinib but not by JakI-1. Together, these data suggest that apoptosis may be suppressed in PVTL-1 cells through inactivation of GSK3 by Lyn as well as Jak2-V617F and additionally through activation of STAT5 by Jak2-V617F. It is also speculated that activation of the mTOR/p70S6K/4EBP1 pathway may mediate proliferation signaling from Jak2-V617F and Lyn. PVTL-1 cells may provide a valuable model system to elucidate the molecular mechanisms involved in evolution of Jak2-V617F-expressing MPN to AML and to develop novel therapies against this intractable condition.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism*
  • Apoptosis / drug effects
  • Bone Marrow / metabolism
  • Bone Marrow / pathology
  • Cell Cycle Proteins
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cell Survival / drug effects
  • Cell Survival / genetics
  • Cell Transformation, Neoplastic / genetics
  • Cell Transformation, Neoplastic / metabolism
  • DNA Mutational Analysis
  • Dasatinib
  • Female
  • Glycogen Synthase Kinase 3 / metabolism*
  • Humans
  • Janus Kinase 2 / genetics
  • Janus Kinase 2 / metabolism*
  • Karyotype
  • Leukemia, Myeloid, Acute / diagnosis
  • Leukemia, Myeloid, Acute / genetics
  • Leukemia, Myeloid, Acute / metabolism*
  • Middle Aged
  • Mutation
  • Phosphoproteins / metabolism*
  • Phosphorylation / drug effects
  • Polycythemia Vera / diagnosis
  • Polycythemia Vera / genetics
  • Polycythemia Vera / metabolism*
  • Protein Kinase Inhibitors / pharmacology
  • Pyrimidines / pharmacology
  • Ribosomal Protein S6 Kinases, 70-kDa / metabolism*
  • Signal Transduction / drug effects
  • Thiazoles / pharmacology
  • src-Family Kinases / genetics
  • src-Family Kinases / metabolism*

Substances

  • Adaptor Proteins, Signal Transducing
  • Cell Cycle Proteins
  • EIF4EBP1 protein, human
  • Phosphoproteins
  • Protein Kinase Inhibitors
  • Pyrimidines
  • Thiazoles
  • Janus Kinase 2
  • lyn protein-tyrosine kinase
  • src-Family Kinases
  • Ribosomal Protein S6 Kinases, 70-kDa
  • Glycogen Synthase Kinase 3
  • Dasatinib

Grants and funding

This study was supported by grants from Ministry of Education, Culture, Sports, Science and Technology of Japan (grant numbers 21591194, 24591384, 22591030, and 24790966). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. No additional external funding received for this study.