Fink Madeline, Al Mamun Bhuyan Abdulla, Zacharopoulou Nefeli, Lang Florian
Department of a Cardiology, Eberhard-Karls-University, Tuebingen, Germany.
Department of Cardiovascular Medicine and Physiology, Eberhard-Karls-University, Tuebingen, Germany.
Cell Physiol Biochem. 2018;51(2):501-512. doi: 10.1159/000495272. Epub 2018 Nov 20.
BACKGROUND/AIMS: The taurine derivative Taurolidine is effective against diverse bacteria and tumor growth. In the treatment of cancer, the substance is effective in part by triggering suicidal death or apoptosis of tumor cells. The Taurolidine-induced apoptosis involves mitochondria. Erythrocytes lack mitochondria but are nevertheless able to enter suicidal erythrocyte death or eryptosis, which is characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Signaling of eryptosis includes increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress and ceramide. The present study explores, whether Taurolidine induces eryptosis and, if so, which cellular mechanisms are involved.
Phosphatidylserine exposure at the cell surface was estimated using annexin-V-binding, cell volume using forward scatter, [Ca2+]i using Fluo3-fuorescence, reactive oxygen species (ROS) formation using 2',7'-dichlorodihydrofuorescein (DCF)-dependent fluorescence, and ceramide abundance using specific antibodies.
A 48 hours exposure of human erythrocytes to Taurolidine (60 µg/ml) significantly enhanced the percentage of annexin-V-binding cells, significantly decreased forward scatter and significantly increased Fluo3-fluorescence and ceramide abundance, but not DCF-fluorescence. The effect of Taurolidine on annexin-V-binding was virtually abrogated by removal of extracellular Ca2+.
Taurolidine triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect at least in part due to Ca2+ entry and paralleled by increase of ceramide abundance.
背景/目的：牛磺酸衍生物陶罗立定对多种细菌及肿瘤生长有效。在癌症治疗中，该物质部分通过触发肿瘤细胞的自杀性死亡或凋亡发挥作用。陶罗立定诱导的凋亡涉及线粒体。红细胞缺乏线粒体，但仍能够发生自杀性红细胞死亡或红细胞凋亡，其特征为细胞皱缩以及细胞膜磷脂酰丝氨酸易位导致的细胞膜磷脂紊乱。红细胞凋亡的信号传导包括胞质Ca2+活性（[Ca2+]i）增加、氧化应激和神经酰胺。本研究探讨陶罗立定是否诱导红细胞凋亡，若如此，涉及哪些细胞机制。
使用膜联蛋白V结合法评估细胞表面磷脂酰丝氨酸暴露情况，通过前向散射评估细胞体积，利用Fluo3荧光评估[Ca2+]i，采用依赖2',7'-二氯二氢荧光素（DCF）的荧光评估活性氧（ROS）形成，并用特异性抗体评估神经酰胺丰度。
人红细胞暴露于陶罗立定（60μg/ml）48小时后，膜联蛋白V结合细胞的百分比显著增加，前向散射显著降低，Fluo3荧光和神经酰胺丰度显著增加，但DCF荧光未增加。去除细胞外Ca2+后，陶罗立定对膜联蛋白V结合的影响几乎消除。
陶罗立定触发红细胞细胞膜皱缩和磷脂紊乱，该效应至少部分归因于Ca2+内流，并伴有神经酰胺丰度增加。
