Lupescu Adrian, Bissinger Rosi, Warsi Jamshed, Jilani Kashif, Lang Florian
Department of Physiology, University of Tübingen, Germany.
Cell Physiol Biochem. 2014;33(6):1838-48. doi: 10.1159/000362962. Epub 2014 Jun 20.
BACKGROUND/AIMS: Gedunin, an inhibitor of heat shock protein HSP90, triggers apoptosis of tumor cells and is thus effective against malignancy. Moreover, the drug has antimalarial potency. In analogy to apoptosis of nucleated cells, erythrocytes may enter suicidal death or eryptosis, which is characterized by cell shrinkage and by phosphatidylserine translocation to the erythrocyte surface. Eryptosis may be triggered by increase of cytosolic Ca(2+)-activity ([Ca(2+)]i). The present study explored whether gedunin stimulates eryptosis.
Forward scatter was determined to estimate cell volume, annexin V binding to identify phosphatidylserine-exposing erythrocytes, hemoglobin release to depict hemolysis, and Fluo3-fluorescence to quantify [Ca(2+)]i.
A 48 h exposure of human erythrocytes to gedunin significantly increased [Ca(2+)]i (12 µM), significantly decreased forward scatter (24 µM) and significantly increased annexin-V-binding (12 µM). The effect of gedunin (24 µM) on annexin-V-binding was virtually abrogated by removal of extracellular Ca(2+).
Gedunin stimulates suicidal erythrocyte death or eryptosis, an effect mainly if not exclusively due to stimulation of Ca(2+) entry.
背景/目的：格杜宁是热休克蛋白HSP90的抑制剂，可触发肿瘤细胞凋亡，因此对恶性肿瘤有效。此外，该药物具有抗疟效力。与有核细胞凋亡类似，红细胞可能进入自杀性死亡或红细胞凋亡，其特征是细胞收缩以及磷脂酰丝氨酸易位至红细胞表面。红细胞凋亡可能由胞质Ca(2+)活性（[Ca(2+)]i）增加所触发。本研究探讨了格杜宁是否会刺激红细胞凋亡。
通过测定前向散射来估计细胞体积，利用膜联蛋白V结合来识别暴露磷脂酰丝氨酸的红细胞，通过血红蛋白释放来描述溶血情况，并使用Fluo3荧光来量化[Ca(2+)]i。
将人红细胞暴露于格杜宁48小时可显著增加[Ca(2+)]i（12 μM），显著降低前向散射（24 μM），并显著增加膜联蛋白V结合（12 μM）。去除细胞外Ca(2+)后，格杜宁（24 μM）对膜联蛋白V结合的作用几乎完全消除。
格杜宁可刺激红细胞自杀性死亡或红细胞凋亡，这种作用主要（如果不是唯一的话）是由于刺激Ca(2+)内流所致。
