title: Induction of Suicidal Erythrocyte Death by Cantharidin.
abstract: The natural phosphoprotein phosphatase inhibitor cantharidin, primarily used for topical treatment of warts, has later been shown to trigger tumor cell apoptosis and is thus considered for the treatment of malignancy. Similar to apoptosis of tumor cells, erythrocytes may undergo eryptosis, a suicidal cell death characterized by cell shrinkage and translocation of cell membrane phosphatidylserine to the erythrocyte surface. Signaling of eryptosis includes increase of cytosolic Ca2+-activity ([Ca2+]i), ceramide, oxidative stress and dysregulation of several kinases. Phosphatidylserine abundance at the erythrocyte surface was quantified utilizing annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, ceramide from antibody binding, and reactive oxidant species (ROS) from 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) fluorescence. A 48 h treatment of human erythrocytes with cantharidin significantly increased the percentage of annexin-V-binding cells (≥10 mg/mL), significantly decreased forward scatter (≥25 mg/mL), significantly increased [Ca2+]i (≥25 mg/mL), but did not significantly modify ceramide abundance or ROS. The up-regulation of annexin-V-binding following cantharidin treatment was not significantly blunted by removal of extracellular Ca2+ but was abolished by kinase inhibitor staurosporine (1 mM) and slightly decreased by p38 inhibitor skepinone (2 mM). Exposure of erythrocytes to cantharidin triggers suicidal erythrocyte death with erythrocyte shrinkage and erythrocyte membrane scrambling, an effect sensitive to kinase inhibitors staurosporine and skepinone.
authors.affiliation: Department of Physiology, University of Tuebingen, Gmelinstr. 5, Tuebingen 72076, Germany. kossai.z@gmail.com.
authors.forename: Kousi
authors.initials: K
authors.lastname: Alzoubi
authors.affiliation: Department of Physiology, University of Tuebingen, Gmelinstr. 5, Tuebingen 72076, Germany. jasmin.egler@t-online.de.
authors.forename: Jasmin
authors.initials: J
authors.lastname: Egler
authors.affiliation: Department of Biological and Environmental Sciences, University of Messina, Viale Ferdinando Stagno d'Alcontres 31, S. Agata-Messina 98166, Italy. marilenabriglia@icloud.com.
authors.forename: Marilena
authors.initials: M
authors.lastname: Briglia
authors.affiliation: Department of Biological and Environmental Sciences, University of Messina, Viale Ferdinando Stagno d'Alcontres 31, S. Agata-Messina 98166, Italy. Antonellafazio89@gmail.com.
authors.forename: Antonella
authors.initials: A
authors.lastname: Fazio
authors.affiliation: Department of Biological and Environmental Sciences, University of Messina, Viale Ferdinando Stagno d'Alcontres 31, S. Agata-Messina 98166, Italy. cfaggio@unime.it.
authors.forename: Caterina
authors.initials: C
authors.lastname: Faggio
authors.affiliation: Department of Physiology, University of Tuebingen, Gmelinstr. 5, Tuebingen 72076, Germany. florian.lang@uni-tuebingen.de.
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
mesh_terms: D002118:Calcium / Q000378:metabolism; D002193:Cantharidin / Q000633:toxicity*; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D002518:Ceramides / Q000378:metabolism; D004910:Erythrocyte Membrane / Q000187:drug effects; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D010718:Phosphatidylserines / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D002518:Ceramides; D010718:Phosphatidylserines; D017382:Reactive Oxygen Species; D002193:Cantharidin; D002118:Calcium
keywords: calcium; cell volume; eryptosis; kinase; phosphatidylserine; staurosporine