Healthy CD4+ T lymphocytes are not affected by targeted therapies against the PI3K/Akt/mTOR pathway in T-cell acute lymphoblastic leukemia

Ayman A M Alameen, Carolina Simioni, Alberto M. Martelli, Giorgio Zauli, Simona Ultimo, James A. McCubrey, Arianna Gonelli, Giorgia Marisi, Paola Ulivi, Silvano Capitani, Luca M. Neri

Research output: Contribution to journalArticle

Abstract

An attractive molecular target for novel anti-cancer therapies is the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway which is commonly deregulated in many types of cancer. Nevertheless, the effects of PI3K/Akt/mTOR inhibitors on T lymphocytes, a key component of immune responses, have been seldom explored. In this study we investigated the effects on human CD4+ T-cells of a panel of PI3K/Akt/mTOR inhibitors: BGT226, Torin-2, MK- 2206, and ZSTK474. We also assessed their efficacy against two acute leukemia T cell lines. T lymphocytes were stimulated with phytohemagglutinin. Inhibitor effects on cell cycle and apoptosis were analyzed by flow cytometry, while cytotoxicity was assessed by MTT assays. In addition, the activation status of the pathway as well as induction of autophagy were analyzed by Western blotting. Quiescent healthy T lymphocytes were unaffected by the drugs whereas mitogenstimulated lymphocytes as well as leukemic cell lines displayed a cell cycle block, caspase-dependent apoptosis, and dephosphorylation of key components of the signaling pathway. Autophagy was also induced in proliferating lymphocytes and in JURKAT and MOLT-4 cell lines. When autophagy was inhibited by 3-methyladenine or Bafilomycin A1, drug cytotoxicity was increased, indicating that autophagy is a protective mechanism. Therefore, our findings suggest that PI3K/Akt/mTOR inhibitors preserve lymphocyte viability. This is a valuable result to be taken into account when selecting drugs for targeted cancer therapy in order to minimize detrimental effects on immune function.

Original languageEnglish
Pages (from-to)55690-55703
Number of pages14
JournalOncotarget
Volume7
Issue number34
DOIs
Publication statusPublished - 2016

Keywords

  • Autophagy
  • PI3K/Akt/mTOR signaling
  • T lymphocytes
  • T-acute lymphoblastic leukemia
  • Targeted therapies

ASJC Scopus subject areas

  • Oncology

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    Alameen, A. A. M., Simioni, C., Martelli, A. M., Zauli, G., Ultimo, S., McCubrey, J. A., Gonelli, A., Marisi, G., Ulivi, P., Capitani, S., & Neri, L. M. (2016). Healthy CD4+ T lymphocytes are not affected by targeted therapies against the PI3K/Akt/mTOR pathway in T-cell acute lymphoblastic leukemia. Oncotarget, 7(34), 55690-55703. https://doi.org/10.18632/oncotarget.10984