PMID- 24907655 OWN - NLM STAT- MEDLINE DCOM- 20140923 LR - 20211203 IS - 1090-2422 (Electronic) IS - 0014-4827 (Linking) VI - 326 IP - 1 DP - 2014 Aug 1 TI - Idarubicin induces mTOR-dependent cytotoxic autophagy in leukemic cells. PG - 90-102 LID - S0014-4827(14)00229-8 [pii] LID - 10.1016/j.yexcr.2014.05.021 [doi] AB - We investigated if the antileukemic drug idarubicin induces autophagy, a process of programmed cellular self-digestion, in leukemic cell lines and primary leukemic cells. Transmission electron microscopy and acridine orange staining demonstrated the presence of autophagic vesicles and intracellular acidification, respectively, in idarubicin-treated REH leukemic cell line. Idarubicin increased punctuation/aggregation of microtubule-associated light chain 3B (LC3B), enhanced the conversion of LC3B-I to autophagosome-associated LC3B-II in the presence of proteolysis inhibitors, and promoted the degradation of the selective autophagic target p62, thus indicating the increase in autophagic flux. Idarubicin inhibited the phosphorylation of the main autophagy repressor mammalian target of rapamycin (mTOR) and its downstream target p70S6 kinase. The treatment with the mTOR activator leucine prevented idarubicin-mediated autophagy induction. Idarubicin-induced mTOR repression was associated with the activation of the mTOR inhibitor AMP-activated protein kinase and down-regulation of the mTOR activator Akt. The suppression of autophagy by pharmacological inhibitors or LC3B and beclin-1 genetic knockdown rescued REH cells from idarubicin-mediated oxidative stress, mitochondrial depolarization, caspase activation and apoptotic DNA fragmentation. Idarubicin also caused mTOR inhibition and cytotoxic autophagy in K562 leukemic cell line and leukocytes from chronic myeloid leukemia patients, but not healthy controls. By demonstrating mTOR-dependent cytotoxic autophagy in idarubicin-treated leukemic cells, our results warrant caution when considering combining idarubicin with autophagy inhibitors in leukemia therapy. CI - Copyright (c) 2014 Elsevier Inc. All rights reserved. FAU - Ristic, Biljana AU - Ristic B AD - Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia. FAU - Bosnjak, Mihajlo AU - Bosnjak M AD - Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade, Serbia. FAU - Arsikin, Katarina AU - Arsikin K AD - Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia. FAU - Mircic, Aleksandar AU - Mircic A AD - Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade, Serbia. FAU - Suzin-Zivkovic, Violeta AU - Suzin-Zivkovic V AD - Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade, Serbia. FAU - Bogdanovic, Andrija AU - Bogdanovic A AD - Clinic for Hematology, Clinical Centre of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia. FAU - Perovic, Vladimir AU - Perovic V AD - Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia. FAU - Martinovic, Tamara AU - Martinovic T AD - Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade, Serbia. FAU - Kravic-Stevovic, Tamara AU - Kravic-Stevovic T AD - Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade, Serbia. FAU - Bumbasirevic, Vladimir AU - Bumbasirevic V AD - Institute of Histology and Embryology, School of Medicine, University of Belgrade, Belgrade, Serbia. FAU - Trajkovic, Vladimir AU - Trajkovic V AD - Institute of Microbiology and Immunology, School of Medicine, University of Belgrade, Dr. Subotica 1, 11000 Belgrade, Serbia. Electronic address: vtrajkovic@med.bg.ac.rs. FAU - Harhaji-Trajkovic, Ljubica AU - Harhaji-Trajkovic L AD - Institute for Biological Research, University of Belgrade, Belgrade, Despot Stefan Blvd. 142, 11000 Belgrade, Serbia. Electronic address: buajk@yahoo.com. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20140605 PL - United States TA - Exp Cell Res JT - Experimental cell research JID - 0373226 RN - 0 (Antibiotics, Antineoplastic) RN - 0 (Apoptosis Regulatory Proteins) RN - 0 (BECN1 protein, human) RN - 0 (Beclin-1) RN - 0 (Membrane Proteins) RN - EC 2.7.1.1 (MTOR protein, human) RN - EC 2.7.11.1 (Proto-Oncogene Proteins c-akt) RN - EC 2.7.11.1 (TOR Serine-Threonine Kinases) RN - ZRP63D75JW (Idarubicin) SB - IM MH - Adult MH - Antibiotics, Antineoplastic/*pharmacology MH - Apoptosis/drug effects MH - Apoptosis Regulatory Proteins/metabolism MH - Autophagy/*drug effects MH - Beclin-1 MH - Cell Proliferation/drug effects MH - Humans MH - Idarubicin/*pharmacology MH - Immunoenzyme Techniques MH - Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy/metabolism/*pathology MH - Lymphocytes/cytology/drug effects/metabolism MH - Membrane Potential, Mitochondrial/drug effects MH - Membrane Proteins/metabolism MH - Microscopy, Electron, Scanning MH - Microscopy, Fluorescence MH - Phosphorylation/drug effects MH - Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy/metabolism/*pathology MH - Proto-Oncogene Proteins c-akt/metabolism MH - Signal Transduction/drug effects MH - TOR Serine-Threonine Kinases/*metabolism MH - Tumor Cells, Cultured OTO - NOTNLM OT - Apoptosis OT - Autophagy OT - Idarubicin OT - Leukemia OT - mTOR EDAT- 2014/06/08 06:00 MHDA- 2014/09/24 06:00 CRDT- 2014/06/08 06:00 PHST- 2014/03/07 00:00 [received] PHST- 2014/05/21 00:00 [revised] PHST- 2014/05/26 00:00 [accepted] PHST- 2014/06/08 06:00 [entrez] PHST- 2014/06/08 06:00 [pubmed] PHST- 2014/09/24 06:00 [medline] AID - S0014-4827(14)00229-8 [pii] AID - 10.1016/j.yexcr.2014.05.021 [doi] PST - ppublish SO - Exp Cell Res. 2014 Aug 1;326(1):90-102. doi: 10.1016/j.yexcr.2014.05.021. Epub 2014 Jun 5.