title: Changes in mitochondrial redox state, membrane potential and calcium precede mitochondrial dysfunction in doxorubicin-induced cell death.
abstract: Mitochondria play central roles in cell life as a source of energy and in cell death by inducing apoptosis. Many important functions of mitochondria change in cancer, and these organelles can be a target of chemotherapy. The widely used anticancer drug doxorubicin (DOX) causes cell death, inhibition of cell cycle/proliferation and mitochondrial impairment. However, the mechanism of such impairment is not completely understood. In our study we used confocal and two-photon fluorescence imaging together with enzymatic and respirometric analysis to study short- and long-term effects of doxorubicin on mitochondria in various human carcinoma cells. We show that short-term (<30 min) effects include i) rapid changes in mitochondrial redox potentials towards a more oxidized state (flavoproteins and NADH), ii) mitochondrial depolarization, iii) elevated matrix calcium levels, and iv) mitochondrial ROS production, demonstrating a complex pattern of mitochondrial alterations. Significant inhibition of mitochondrial endogenous and uncoupled respiration, ATP depletion and changes in the activities of marker enzymes were observed after 48 h of DOX treatment (long-term effects) associated with cell cycle arrest and death.
authors.affiliation: Department of Heart Surgery, Innsbruck Medical University, Innrain 66, Innsbruck A-6020, Austria. andrey.kuznetsov@uki.at
authors.forename: Andrey V
authors.initials: AV
authors.lastname: Kuznetsov
authors.forename: Raimund
authors.initials: R
authors.lastname: Margreiter
authors.forename: Albert
authors.initials: A
authors.lastname: Amberger
authors.forename: Valdur
authors.initials: V
authors.lastname: Saks
authors.forename: Michael
authors.initials: M
authors.lastname: Grimm
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism*; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D019069:Cell Respiration / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002950:Citrate (si)-Synthase / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000494:pharmacology*; D042967:Electron Transport Complex I / Q000378:metabolism; D019073:HT29 Cells; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects*; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D010084:Oxidation-Reduction / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D013997:Time Factors; D014475:Uncoupling Agents / Q000494:pharmacology
chemical_list: D000903:Antibiotics, Antineoplastic; D017382:Reactive Oxygen Species; D014475:Uncoupling Agents; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D004317:Doxorubicin; D000255:Adenosine Triphosphate; D002950:Citrate (si)-Synthase; D042967:Electron Transport Complex I; D002118:Calcium