title: Mitochondria-derived reactive oxygen species drive GANT61-induced mesothelioma cell apoptosis.
abstract: Gli transcription factors of the Hedgehog (Hh) pathway have been reported to be drivers of malignant mesothelioma (MMe) cell survival. The Gli inhibitor GANT61 induces apoptosis in various cancer cell models, and has been associated directly with Gli inhibition. However various chemotherapeutics can induce cell death through generation of reactive oxygen species (ROS) but whether ROS mediates GANT61-induced apoptosis is unknown. In this study human MMe cells were treated with GANT61 and the mechanisms regulating cell death investigated. Exposure of MMe cells to GANT61 led to G1 phase arrest and apoptosis, which involved ROS but not its purported targets, GLI1 or GLI2. GANT61 triggered ROS generation and quenching of ROS protected MMe cells from GANT61-induced apoptosis. Furthermore, we demonstrated that mitochondria are important in mediating GANT61 effects: (1) ROS production and apoptosis were blocked by mitochondrial inhibitor rotenone; (2) GANT61 promoted superoxide formation in mitochondria; and (3) mitochondrial DNA-deficient LO68 cells failed to induce superoxide, and were more resistant to apoptosis induced by GANT61 than wild-type cells. Our data demonstrate for the first time that GANT61 induces apoptosis by promoting mitochondrial superoxide generation independent of Gli inhibition, and highlights the therapeutic potential of mitochondrial ROS-mediated anticancer drugs in MMe.
authors.affiliation: Lung Institute of Western Australia and Centre for Asthma, Allergy and Respiratory Research, School of Medicine and Pharmacology, University of Western Australia, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.
authors.forename: Chuan Bian
authors.initials: CB
authors.lastname: Lim
authors.affiliation: Lung Institute of Western Australia and Centre for Asthma, Allergy and Respiratory Research, School of Medicine and Pharmacology, University of Western Australia, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.|Centre for Cell Therapy and Regenerative Medicine, School of Medicine and Pharmacology, University of Western Australia and Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.
authors.forename: Cecilia M
authors.initials: CM
authors.lastname: Prêle
authors.affiliation: Lung Institute of Western Australia and Centre for Asthma, Allergy and Respiratory Research, School of Medicine and Pharmacology, University of Western Australia, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Baltic
authors.affiliation: School of Chemistry and Biochemistry, University of Western Australia, Crawley, WA, Australia.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Arthur
authors.affiliation: National Centre for Asbestos Related Diseases, School of Medicine and Pharmacology, University of Western Australia, Harry Perkins Institute of Medical Research and Australian Mesothelioma Tissue Bank, Sir Charles Gairdner Hospital, Nedlands, WA, Australia.
authors.forename: Jenette
authors.initials: J
authors.lastname: Creaney
authors.affiliation: Garvan Institute of Medical Research, Darlinghurst, NSW, Australia.
authors.forename: D Neil
authors.initials: DN
authors.lastname: Watkins
authors.affiliation: Lung Institute of Western Australia and Centre for Asthma, Allergy and Respiratory Research, School of Medicine and Pharmacology, University of Western Australia, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Thompson
authors.affiliation: Lung Institute of Western Australia and Centre for Asthma, Allergy and Respiratory Research, School of Medicine and Pharmacology, University of Western Australia, Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.|Centre for Cell Therapy and Regenerative Medicine, School of Medicine and Pharmacology, University of Western Australia and Harry Perkins Institute of Medical Research, Nedlands, WA, Australia.
authors.forename: Steven E
authors.initials: SE
authors.lastname: Mutsaers
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D045744:Cell Line, Tumor; D016193:G1 Phase / Q000187:drug effects; D045325:HCT116 Cells; D019073:HT29 Cells; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008654:Mesothelioma / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D000086002:Mesothelioma, Malignant; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D011725:Pyridines / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D000071676:Zinc Finger Protein GLI1
chemical_list: C551027:GANT 61; C400551:GLI1 protein, human; D011725:Pyridines; D011743:Pyrimidines; D017382:Reactive Oxygen Species; D014157:Transcription Factors; D000071676:Zinc Finger Protein GLI1