title: ATG7 regulates energy metabolism, differentiation and survival of Philadelphia-chromosome-positive cells.
abstract: A major drawback of tyrosine kinase inhibitor (TKI) treatment in chronic myeloid leukemia (CML) is that primitive CML cells are able to survive TKI-mediated BCR-ABL inhibition, leading to disease persistence in patients. Investigation of strategies aiming to inhibit alternative survival pathways in CML is therefore critical. We have previously shown that a nonspecific pharmacological inhibition of autophagy potentiates TKI-induced death in Philadelphia chromosome-positive cells. Here we provide further understanding of how specific and pharmacological autophagy inhibition affects nonmitochondrial and mitochondrial energy metabolism and reactive oxygen species (ROS)-mediated differentiation of CML cells and highlight ATG7 (a critical component of the LC3 conjugation system) as a potential specific therapeutic target. By combining extra- and intracellular steady state metabolite measurements by liquid chromatography-mass spectrometry with metabolic flux assays using labeled glucose and functional assays, we demonstrate that knockdown of ATG7 results in decreased glycolysis and increased flux of labeled carbons through the mitochondrial tricarboxylic acid cycle. This leads to increased oxidative phosphorylation and mitochondrial ROS accumulation. Furthermore, following ROS accumulation, CML cells, including primary CML CD34(+) progenitor cells, differentiate toward the erythroid lineage. Finally, ATG7 knockdown sensitizes CML progenitor cells to TKI-induced death, without affecting survival of normal cells, suggesting that specific inhibitors of ATG7 in combination with TKI would provide a novel therapeutic approach for CML patients exhibiting persistent disease.
authors.affiliation: a Paul O'Gorman Leukemia Research Center, College of Medical, Veterinary and Life Sciences, Institute of Cancer Sciences, University of Glasgow , Glasgow , UK.
authors.forename: Maria
authors.initials: M
authors.lastname: Karvela
authors.affiliation: b Wolfson Wohl Cancer Research Center, College of Medical, Veterinary & Life Sciences, Institute of Cancer Sciences, University of Glasgow , UK.
authors.forename: Pablo
authors.initials: P
authors.lastname: Baquero
authors.affiliation: c Cancer Research UK, Beatson Institute, Garscube Estate, Switchback Road , Glasgow , UK.
authors.forename: Elodie M
authors.initials: EM
authors.lastname: Kuntz
authors.affiliation: a Paul O'Gorman Leukemia Research Center, College of Medical, Veterinary and Life Sciences, Institute of Cancer Sciences, University of Glasgow , Glasgow , UK.
authors.forename: Arunima
authors.initials: A
authors.lastname: Mukhopadhyay
authors.affiliation: b Wolfson Wohl Cancer Research Center, College of Medical, Veterinary & Life Sciences, Institute of Cancer Sciences, University of Glasgow , UK.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Mitchell
authors.affiliation: d Scottish National Blood Transfusion Service, Gartnavel General Hospital , Glasgow , UK.
authors.forename: Elaine K
authors.initials: EK
authors.lastname: Allan
authors.affiliation: e Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde , Glasgow , UK.
authors.forename: Edmond
authors.initials: E
authors.lastname: Chan
authors.affiliation: f Medical Research Council Center for Regenerative Medicine, University of Edinburgh , Edinburgh , UK.
authors.forename: Kamil R
authors.initials: KR
authors.lastname: Kranc
authors.affiliation: g Department of Cancer Biology , Kimmel Cancer Center, Thomas Jefferson University , Philadelphia , PA USA.
authors.forename: Bruno
authors.initials: B
authors.lastname: Calabretta
authors.affiliation: h Samantha Dickson Brain Cancer Unit, UCL Cancer Institute, Paul O'Gorman Building , London , UK.
authors.forename: Paolo
authors.initials: P
authors.lastname: Salomoni
authors.affiliation: c Cancer Research UK, Beatson Institute, Garscube Estate, Switchback Road , Glasgow , UK.
authors.forename: Eyal
authors.initials: E
authors.lastname: Gottlieb
authors.affiliation: a Paul O'Gorman Leukemia Research Center, College of Medical, Veterinary and Life Sciences, Institute of Cancer Sciences, University of Glasgow , Glasgow , UK.
authors.forename: Tessa L
authors.initials: TL
authors.lastname: Holyoake
authors.affiliation: b Wolfson Wohl Cancer Research Center, College of Medical, Veterinary & Life Sciences, Institute of Cancer Sciences, University of Glasgow , UK.
authors.forename: G Vignir
authors.initials: GV
authors.lastname: Helgason
mesh_terms: D000818:Animals; D018952:Antigens, CD34 / Q000378:metabolism; D001343:Autophagy / Q000187:drug effects; D000071193:Autophagy-Related Protein 7 / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects; D019069:Cell Respiration / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002952:Citric Acid Cycle / Q000187:drug effects; D004195:Disease Models, Animal; D004734:Energy Metabolism / Q000187:drug effects; D017353:Gene Deletion; D055785:Gene Knockdown Techniques; D006019:Glycolysis / Q000187:drug effects; D006412:Hematopoietic Stem Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D020014:K562 Cells; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000378:metabolism* / Q000473:pathology*; D064688:Metabolic Flux Analysis; D055442:Metabolome / Q000187:drug effects; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D010085:Oxidative Phosphorylation / Q000187:drug effects; D010677:Philadelphia Chromosome; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D013234:Stem Cells / Q000378:metabolism
chemical_list: D018952:Antigens, CD34; D047428:Protein Kinase Inhibitors; D017382:Reactive Oxygen Species; D000071193:Autophagy-Related Protein 7
keywords: ATG7; autophagy; chronic myeloid leukemia; energy metabolism; erythroid differentiation; glycolysis; oxidative phosphorylation; reactive oxygen species; tyrosine kinase inhibitor