Oncogenic tyrosine kinase NPM/ALK induces activation of the rapamycin-sensitive mTOR signaling pathway.

Research output: Contribution to journalJournal articleResearchpeer-review

  • Marzec, Michal Tomasz
  • M. Kasprzycka
  • X. Liu
  • M. El-Salem
  • K. Halasa
  • P. N. Raghunath
  • R. Bucki
  • P. Wlodarski
  • M. A. Wasik
The mechanisms of cell transformation mediated by the nucleophosmin (NPM)/anaplastic lymphoma kinase (ALK) tyrosine kinase are only partially understood. Here, we report that cell lines and native tissues derived from the NPM/ALK-expressing T-cell lymphoma display persistent activation of mammalian target of rapamycin (mTOR) as detd. by phosphorylation of mTOR targets S6rp and 4E-binding protein 1 (4E-BP1). The mTOR activation is serum growth factor-independent but nutrient-dependent. It is also dependent on the expression and enzymic activity of NPM/ALK as demonstrated by cell transfection with wild-type and functionally deficient NPM/ALK, small interfering RNA (siRNA)-mediated NPM/ALK depletion and kinase activity suppression using the inhibitor WHI-P154. The NPM/ALK-induced mTOR activation is transduced through the mitogen-induced extracellular kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathway and, to a much lesser degree, through the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway. Accordingly, whereas the low-dose PI3K inhibitor wortmannin and Akt inhibitor III profoundly inhibited Akt phosphorylation, they had a very modest effect on S6rp and 4E-BP1 phosphorylation. In turn, MEK inhibitors U0126 and PD98059 and siRNA-mediated depletion of either ERK1 or ERK2 inhibited S6rp phosphorylation much more effectively. Finally, the mTOR inhibitor rapamycin markedly decreased proliferation and increased the apoptotic rate of ALK+TCL cells. These findings identify mTOR as a novel key target of NPM/ALK and suggest that mTOR inhibitors may prove effective in therapy of ALK-induced malignancies. [on SciFinder(R)]
Original languageEnglish
Issue number38
Pages (from-to)5606-5614
Number of pages9
Publication statusPublished - 2007
Externally publishedYes

Bibliographical note

M1 - Copyright (C) 2018 American Chemical Society (ACS). All Rights Reserved.

CAPLUS AN 2007:913571(Journal)

    Research areas

  • tyrosine kinase NPM ALK mTOR signaling pathway cancer

ID: 202379063