title: Minnelide/Triptolide Impairs Mitochondrial Function by Regulating SIRT3 in P53-Dependent Manner in Non-Small Cell Lung Cancer.
abstract: Minnelide/Triptolide (TL) has recently emerged as a potent anticancer drug in non-small cell lung cancer (NSCLC). However, the precise mechanism of its action remains ambiguous. In this study, we elucidated the molecular basis for TL-induced cell death in context to p53 status. Cell death was attributed to dysfunction of mitochondrial bioenergetics in p53-deficient cells, which was characterized by decreased mitochondrial respiration, steady-state ATP level and membrane potential, but augmented reactive oxygen species (ROS). Increased ROS production resulted in oxidative stress in TL-treated cells. This was exhibited by elevated nuclear levels of a redox-sensitive transcriptional factor, NF-E2-related factor-2 (NRF2), along with diminished cellular glutathione (GSH) content. We further demonstrated that in the absence of p53, TL blunted the expression of mitochondrial SIRT3 triggering increased acetylation of NDUAF9 and succinate dehydrogenase, components of complexes I and II of the electron transport chain (ETC). TL-mediated hyperacetylation of complexes I and II proteins and these complexes displayed decreased enzymatic activities. We also provide the evidence that P53 regulate steady-state level of SIRT3 through Proteasome-Pathway. Finally, forced overexpression of Sirt3, but not deacetylase-deficient mutant of Sirt3 (H243Y), restored the deleterious effect of TL on p53-deficient cells by rescuing mitochondrial bioenergetics. On contrary, Sirt3 deficiency in the background of wild-type p53 triggered TL-induced mitochondrial impairment that echoed TL effect in p53-deficeint cells. These findings illustrate a novel mechanism by which TL exerts its potent effects on mitochondrial function and ultimately the viability of NSCLC tumor.
authors: Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
authors: Ajay
authors: A
authors: Kumar
authors: Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
authors: Catherine
authors: C
authors: Corey
authors: Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
authors: Iain
authors: I
authors: Scott
authors: Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.|Dept of Pharmacology & Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
authors: Sruti
authors: S
authors: Shiva
authors: Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
authors: Jonathan
authors: J
authors: D'Cunha
mesh_terms: D000107:Acetylation; D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D004224:Diterpenes / Q000494:pharmacology*; D004852:Epoxy Compounds / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D010755:Organophosphates / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects; D010616:Phenanthrenes / Q000494:pharmacology*; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D056566:Sirtuin 3 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D018906:Antineoplastic Agents, Alkylating; D004224:Diterpenes; D004852:Epoxy Compounds; D010755:Organophosphates; D010616:Phenanthrenes; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C001899:triptolide; C579022:14-O-phosphonooxymethyltriptolide disodium salt; C466093:SIRT3 protein, human; D056566:Sirtuin 3