Akt activation through the phosphorylation of erythropoietin receptor at tyrosine 479 is required for myeloproliferative disorder-associated JAK2 V617F mutant-induced cellular transformation

Jun Kamishimoto, Kenji Tago, Tadashi Kasahara, Megumi Tago

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24 Citations (Scopus)

Abstract

The disruption of Janus kinase 2 (JAK2) signaling regulation by its point mutation, V617F, is involved in various myeloproliferative disorders (MPDs). JAK2 V617F mutant induced constitutive activation of Akt when erythropoietin receptor (EpoR) was coexpressed; however, the physiological role of Akt activation in MPDs has not been elucidated. LY294002, a phosphoinositide 3-kinase (PI3K) inhibitor, inhibited Akt activation and induced apoptotic cell death in cells expressing JAK2 V617F mutant and EpoR. Previously, it has been shown that the phosphorylation at Y479 in EpoR is critical for the interaction with PI3K, an upstream molecule of Akt. Hence, EpoR mutant with a point mutation of Y479F, which fails to activate Akt, is useful for addressing the role of Akt activation in JAK2 V617F mutant-induced tumorigenesis. Interestingly, under the expression of EpoR Y479F mutant, JAK2 V617F mutant failed to exhibit potent anti-apoptotic activity. In addition, JAK2 V617F mutant-induced phosphorylation of CREB and GSK-3β was significantly decreased in cells expressing EpoR Y479F mutant, resulting in the downregulation of Bcl-XL and Mcl-1 expression. Furthermore, compared with when nude mice were inoculated with cells expressing JAK2 V617F mutant and EpoR, the lifespan of nude mice inoculated with cells expressing JAK2 V617F mutant and EpoR Y479F mutant was effectively prolonged. Taken together, it was clarified that PI3K-Akt activation through the phosphorylation of EpoR at Y479 is required for oncogenic signaling of JAK2 V617F mutant and that targeted disruption of this pathway has therapeutic utility.

Original languageEnglish
Pages (from-to)849-856
Number of pages8
JournalCellular Signalling
Volume23
Issue number5
DOIs
Publication statusPublished - 2011 May

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Janus Kinase 2
Erythropoietin Receptors
Myeloproliferative Disorders
Tyrosine
Phosphorylation
1-Phosphatidylinositol 4-Kinase
Point Mutation
Nude Mice
Glycogen Synthase Kinase 3
2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
Carcinogenesis
Cell Death
Down-Regulation

Keywords

  • Akt
  • JAK2
  • Myeloproliferative disorder
  • Tumorigenesis
  • V617F mutation

ASJC Scopus subject areas

  • Cell Biology

Cite this

@article{674ced9552c8409cbc94e48105cf9af5,
title = "Akt activation through the phosphorylation of erythropoietin receptor at tyrosine 479 is required for myeloproliferative disorder-associated JAK2 V617F mutant-induced cellular transformation",
abstract = "The disruption of Janus kinase 2 (JAK2) signaling regulation by its point mutation, V617F, is involved in various myeloproliferative disorders (MPDs). JAK2 V617F mutant induced constitutive activation of Akt when erythropoietin receptor (EpoR) was coexpressed; however, the physiological role of Akt activation in MPDs has not been elucidated. LY294002, a phosphoinositide 3-kinase (PI3K) inhibitor, inhibited Akt activation and induced apoptotic cell death in cells expressing JAK2 V617F mutant and EpoR. Previously, it has been shown that the phosphorylation at Y479 in EpoR is critical for the interaction with PI3K, an upstream molecule of Akt. Hence, EpoR mutant with a point mutation of Y479F, which fails to activate Akt, is useful for addressing the role of Akt activation in JAK2 V617F mutant-induced tumorigenesis. Interestingly, under the expression of EpoR Y479F mutant, JAK2 V617F mutant failed to exhibit potent anti-apoptotic activity. In addition, JAK2 V617F mutant-induced phosphorylation of CREB and GSK-3β was significantly decreased in cells expressing EpoR Y479F mutant, resulting in the downregulation of Bcl-XL and Mcl-1 expression. Furthermore, compared with when nude mice were inoculated with cells expressing JAK2 V617F mutant and EpoR, the lifespan of nude mice inoculated with cells expressing JAK2 V617F mutant and EpoR Y479F mutant was effectively prolonged. Taken together, it was clarified that PI3K-Akt activation through the phosphorylation of EpoR at Y479 is required for oncogenic signaling of JAK2 V617F mutant and that targeted disruption of this pathway has therapeutic utility.",
keywords = "Akt, JAK2, Myeloproliferative disorder, Tumorigenesis, V617F mutation",
author = "Jun Kamishimoto and Kenji Tago and Tadashi Kasahara and Megumi Tago",
year = "2011",
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journal = "Cellular Signalling",
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T1 - Akt activation through the phosphorylation of erythropoietin receptor at tyrosine 479 is required for myeloproliferative disorder-associated JAK2 V617F mutant-induced cellular transformation

AU - Kamishimoto, Jun

AU - Tago, Kenji

AU - Kasahara, Tadashi

AU - Tago, Megumi

PY - 2011/5

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N2 - The disruption of Janus kinase 2 (JAK2) signaling regulation by its point mutation, V617F, is involved in various myeloproliferative disorders (MPDs). JAK2 V617F mutant induced constitutive activation of Akt when erythropoietin receptor (EpoR) was coexpressed; however, the physiological role of Akt activation in MPDs has not been elucidated. LY294002, a phosphoinositide 3-kinase (PI3K) inhibitor, inhibited Akt activation and induced apoptotic cell death in cells expressing JAK2 V617F mutant and EpoR. Previously, it has been shown that the phosphorylation at Y479 in EpoR is critical for the interaction with PI3K, an upstream molecule of Akt. Hence, EpoR mutant with a point mutation of Y479F, which fails to activate Akt, is useful for addressing the role of Akt activation in JAK2 V617F mutant-induced tumorigenesis. Interestingly, under the expression of EpoR Y479F mutant, JAK2 V617F mutant failed to exhibit potent anti-apoptotic activity. In addition, JAK2 V617F mutant-induced phosphorylation of CREB and GSK-3β was significantly decreased in cells expressing EpoR Y479F mutant, resulting in the downregulation of Bcl-XL and Mcl-1 expression. Furthermore, compared with when nude mice were inoculated with cells expressing JAK2 V617F mutant and EpoR, the lifespan of nude mice inoculated with cells expressing JAK2 V617F mutant and EpoR Y479F mutant was effectively prolonged. Taken together, it was clarified that PI3K-Akt activation through the phosphorylation of EpoR at Y479 is required for oncogenic signaling of JAK2 V617F mutant and that targeted disruption of this pathway has therapeutic utility.

AB - The disruption of Janus kinase 2 (JAK2) signaling regulation by its point mutation, V617F, is involved in various myeloproliferative disorders (MPDs). JAK2 V617F mutant induced constitutive activation of Akt when erythropoietin receptor (EpoR) was coexpressed; however, the physiological role of Akt activation in MPDs has not been elucidated. LY294002, a phosphoinositide 3-kinase (PI3K) inhibitor, inhibited Akt activation and induced apoptotic cell death in cells expressing JAK2 V617F mutant and EpoR. Previously, it has been shown that the phosphorylation at Y479 in EpoR is critical for the interaction with PI3K, an upstream molecule of Akt. Hence, EpoR mutant with a point mutation of Y479F, which fails to activate Akt, is useful for addressing the role of Akt activation in JAK2 V617F mutant-induced tumorigenesis. Interestingly, under the expression of EpoR Y479F mutant, JAK2 V617F mutant failed to exhibit potent anti-apoptotic activity. In addition, JAK2 V617F mutant-induced phosphorylation of CREB and GSK-3β was significantly decreased in cells expressing EpoR Y479F mutant, resulting in the downregulation of Bcl-XL and Mcl-1 expression. Furthermore, compared with when nude mice were inoculated with cells expressing JAK2 V617F mutant and EpoR, the lifespan of nude mice inoculated with cells expressing JAK2 V617F mutant and EpoR Y479F mutant was effectively prolonged. Taken together, it was clarified that PI3K-Akt activation through the phosphorylation of EpoR at Y479 is required for oncogenic signaling of JAK2 V617F mutant and that targeted disruption of this pathway has therapeutic utility.

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