Calcineurin complex isolated from T-cell acute lymphoblastic leukemia (T-ALL) cells identifies new signaling pathways including mTOR/AKT/S6K whose inhibition synergize with Calcineurin inhibition to promote T-ALL cell death

Valeria Tosello, Valentina Saccomani, Jiyang Yu, Fulvio Bordin, Alberto Amadori, Erich Piovan

Research output: Contribution to journalArticle

Abstract

Calcineurin (Cn) is a calcium activated protein phosphatase involved in many aspects of normal T cell physiology, however the role of Cn and/or its downstream targets in leukemogenesis are still ill-defined. In order to identify putative downstream targets/effectors involved in the pro-oncogenic activity of Cn in T-cell acute lymphoblastic leukemia (T-ALL) we used tandem affinity chromatography, followed by mass spectrometry to purify novel Cn-interacting partners. We found the Cn-interacting proteins to be part of numerous cellular signaling pathways including eIF2 signaling and mTOR signaling. Coherently, modulation of Cn activity in T-ALL cells determined alterations in the phosphorylation status of key molecules implicated in protein translation such as eIF-2α and ribosomal protein S6. Joint targeting of PI3K-mTOR, eIF-2α and 14-3-3 signaling pathways with Cn unveiled novel synergistic pro-apoptotic drug combinations. Further analysis disclosed that the synergistic interaction between PI3K-mTOR and Cn inhibitors was prevalently due to AKT inhibition. Finally, we showed that the synergistic pro-apoptotic response determined by jointly targeting AKT and Cn pathways was linked to down-modulation of key anti-apoptotic proteins including Mcl-1, Claspin and XIAP. In conclusion, we identify AKT inhibition as a novel promising drug combination to potentiate the proapoptotic effects of Cn inhibitors.

Original languageEnglish
Pages (from-to)45715-45729
Number of pages15
JournalOncotarget
Volume7
Issue number29
DOIs
Publication statusPublished - 2016

Keywords

  • Apoptosis
  • Calcineurin
  • MTOR signaling
  • Protein complex
  • T-cell acute lymphoblastic leukemia

ASJC Scopus subject areas

  • Oncology

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