Rapanone, a naturally occurring benzoquinone, inhibits mitochondrial respiration and induces HepG2 cell death

dc.contributor.authorPardo Andreu, Gilberto L.
dc.contributor.authorZuccolotto DosReis, Felipe
dc.contributor.authorGonzález Durruthy, Michael
dc.contributor.authorDelgado Hernández, René
dc.contributor.authorD'Vries, Richard F.
dc.contributor.authorVanden Berghe, Wim
dc.contributor.authorC. Alberici, Luciane
dc.date.accessioned2020-02-09T18:43:43Z
dc.date.available2020-02-09T18:43:43Z
dc.date.issued2019-11-20
dc.description.abstractRapanone is a natural occurring benzoquinone with several biological effects including unclear cytotoxic mechanisms. Here we addressed if mitochondria are involved in the cytotoxicity of rapanone towards cancer cells by employing hepatic carcinoma (HepG2) cells and isolated rat liver mitochondria. In the HepG2, rapanone (20–40 μM) induced a concentration-dependent mitochondrial membrane potential dissipation, ATP depletion, hydrogen peroxide generation and, phosphatidyl serine externalization; the latter being indicative of apoptosis induction. Rapanone toxicity towards primary rats hepatocytes (IC50 = 35.58 ± 1.50 μM) was lower than that found for HepG2 cells (IC50 = 27.89 ± 0.75 μM). Loading of isolated mitochondria with rapanone (5–20 μM) caused a concentration-dependent inhibition of phosphorylating and uncoupled respirations supported by complex I (glutamate and malate) or the complex II (succinate) substrates, being the latter eliminated by complex IV substrate (TMPD/ascorbate). Rapanone also dissipated mitochondrial membrane potential, depleted ATP content, released Ca2+ from Ca2+-loaded mitochondria, increased ROS generation, cytochrome c release and membrane fluidity. Further analysis demonstrated that rapanone prevented the cytochrome c reduction in the presence of decylbenzilquinol, identifying complex III as the site of its inhibitory action. Computational docking results of rapanone to cytochrome bc1 (Cyt bc1) complex from the human sources found spontaneous thermodynamic processes for the quinone-Qo and Qi binding interactions, supporting the experimental in vitro assays. Collectively, these observations suggest that rapanone impairs mitochondrial respiration by inhibiting electron transport chain at Complex III and promotes mitochondrial dysfunction. This property is potentially involved in rapanone toxicity on cancer cells.es
dc.identifier.issn08872333
dc.identifier.urihttps://repositorio.usc.edu.co/handle/20.500.12421/2630
dc.language.isoenes
dc.publisherElsevier Ltdes
dc.subjectRapanonees
dc.subjectMitochondriaes
dc.subjectComplex IIIes
dc.subjectCytotoxicityes
dc.subjectHepG2es
dc.subjectAnticanceres
dc.titleRapanone, a naturally occurring benzoquinone, inhibits mitochondrial respiration and induces HepG2 cell deathes
dc.typeArticlees

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