title: Yeast cytotoxic sensitivity to the antitumour agent β-lapachone depends mainly on oxidative stress and is largely independent of microtubule- or topoisomerase-mediated DNA damage.
abstract: β-Lapachone (β-lap) is a promising antitumour drug currently undergoing clinical trials. Although it is known that β-lap generates reactive oxygen species (ROS), its actual mechanism of action is still controversial. Especially important is to determine whether concomitant DNA or microtubule damage is the key target of its antitumour properties and whether DNA damage is mediated by topoisomerases as previously suggested. Here, we have searched for determinants of β-lap cytotoxicity in the model organism Saccharomyces cerevisiae through a mechanism-driven approach whereby several pathways of the DNA and microtubule integrity responses, as well as the anti-oxidant response, were downregulated and the outcome of β-lap treatment examined. We also included in the analysis several β-lap derivatives expected to modify drug bioavailability and activity. We found that neither topoisomerase II nor microtubules contributed to yeast sensitivity to β-lap and its equitoxic derivative 3-bromo-β-lapachone. Instead, we found that oxidative and related environmental stresses were primarily responsible for toxicity. Accordingly, Yap1, the central transcription factor in the antioxidant response in yeast, together with several components involved in stress tolerance (i.e., Snf1 and Hog1) and chromatin remodelling (i.e., the SWR1 and RSC complexes), played major roles in protection against β-lapachone. Critically, we show that dioxygen enhanced toxicity and that ROS scavengers protected cells from it. Furthermore, we show that both quinones resulted in cell death in a manner which cytologically resembled apoptosis/necrosis. We thus conclude that β-lap is toxic to yeast through massive ROS production that either directly kills the cells or else triggers programmed cell death.
authors.affiliation: Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Carretera del Rosario, 145, 38010 Santa Cruz de Tenerife, Spain; Instituto Canario de Investigación del Cáncer (ICIC), Torre Agustín Arévalo - 7ª Planta (PCTT-ULL), Avda de la Trinidad s/n, 38204 San Cristóbal de La Laguna, Santa Cruz de Tenerife, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Ramos-Pérez
authors.affiliation: Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Carretera del Rosario, 145, 38010 Santa Cruz de Tenerife, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Lorenzo-Castrillejo
authors.affiliation: Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Carretera del Rosario, 145, 38010 Santa Cruz de Tenerife, Spain; Instituto Canario de Investigación del Cáncer (ICIC), Torre Agustín Arévalo - 7ª Planta (PCTT-ULL), Avda de la Trinidad s/n, 38204 San Cristóbal de La Laguna, Santa Cruz de Tenerife, Spain.
authors.forename: Oliver
authors.initials: O
authors.lastname: Quevedo
authors.affiliation: Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Carretera del Rosario, 145, 38010 Santa Cruz de Tenerife, Spain; Instituto Canario de Investigación del Cáncer (ICIC), Torre Agustín Arévalo - 7ª Planta (PCTT-ULL), Avda de la Trinidad s/n, 38204 San Cristóbal de La Laguna, Santa Cruz de Tenerife, Spain.
authors.forename: Jonay
authors.initials: J
authors.lastname: García-Luis
authors.affiliation: Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Carretera del Rosario, 145, 38010 Santa Cruz de Tenerife, Spain.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Matos-Perdomo
authors.affiliation: Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Carretera del Rosario, 145, 38010 Santa Cruz de Tenerife, Spain.
authors.forename: Chaxiraxi
authors.initials: C
authors.lastname: Medina-Coello
authors.affiliation: Instituto Canario de Investigación del Cáncer (ICIC), Torre Agustín Arévalo - 7ª Planta (PCTT-ULL), Avda de la Trinidad s/n, 38204 San Cristóbal de La Laguna, Santa Cruz de Tenerife, Spain; Instituto Universitario de Bio-Orgánica Antonio González (CIBICAN), Departamento de Química Orgánica, Universidad de La Laguna, Avda. Astrofísico Fco, Sánchez 2, 38206 La Laguna, Tenerife, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Estévez-Braun
authors.affiliation: Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Carretera del Rosario, 145, 38010 Santa Cruz de Tenerife, Spain; Instituto Canario de Investigación del Cáncer (ICIC), Torre Agustín Arévalo - 7ª Planta (PCTT-ULL), Avda de la Trinidad s/n, 38204 San Cristóbal de La Laguna, Santa Cruz de Tenerife, Spain. Electronic address: fmacconw@gmail.com.
authors.forename: Félix
authors.initials: F
authors.lastname: Machín
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000633:toxicity*; D004249:DNA Damage / Q000187:drug effects / Q000502:physiology*; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism*; D009285:Naphthoquinones / Q000737:chemistry / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D021281:Quantitative Structure-Activity Relationship; D017382:Reactive Oxygen Species / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D009285:Naphthoquinones; D017382:Reactive Oxygen Species; C014638:beta-lapachone; D004264:DNA Topoisomerases, Type I
keywords: DMSO (PubChem CID: 679); DNA damage; H(2)O(2) (PubChem CID: 784); MMS (PubChem CID: 4156); Menadione (PubChem CID: 4055); Microtubules; Oxidative stress; Saccharomyces cerevisiae; Top2; Yap1; β-Lapachone; β-Lapachone (PubChem CID: 3885)