scholarly journals Stimulation of Erythrocyte Cell Membrane Scrambling by Adarotene

2017 ◽  
Vol 41 (2) ◽  
pp. 519-529 ◽  
Author(s):  
Morena Mischitelli ◽  
Mohamed Jemaàa ◽  
MyriamFezai Fezai ◽  
Mustafa Almasry ◽  
Florian Lang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Membrane ◽  
Annexin V ◽  
Forward Scatter ◽  
Erythrocyte Surface ◽  
Suicidal Death ◽  
Phosphatidylserine Translocation ◽  
Surface Signaling ◽  
Ros Formation ◽  
Stimulation Of

Background/Aims: The atypical retinoid E23-(40-hydroxyl-30-adamantylbiphenyl-4-yl) acrylic acid (ST1926, adarotene) is used in the treatment of malignancy. The effect of ST1926 is at least in part due to stimulation of apoptosis. Similar to apoptosis of nucleated cells, erythrocytes may enter eryptosis, the suicidal death of erythrocytes. Hallmarks of eryptosis include cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Signaling involved in the stimulation of eryptosis includes increase of cytosolic Ca2+ activity [Ca2+]<Sub>i</Sub>, oxidative stress and ceramide. The present study explored, whether adarotene induces eryptosis and, if so, to test for the involvement of Ca2+ entry, oxidative stress and ceramide. Methods: Flow cytometry was employed to estimate phosphatidylserine exposure at the cell surface from annexin-V-binding, cell volume from forward scatter, [Ca2+]<Sub>i</Sub> from Fluo3-fluorescence, reactive oxygen species (ROS) formation from DCFDA dependent fluorescence, and ceramide abundance utilizing specific antibodies. Results: A 48 hours exposure of human erythrocytes to adarotene (9 µM) significantly increased the percentage of annexin-V-binding cells, an effect paralleled by significant decrease of forward scatter, as well as significant increase of Fluo3-fluorescence, DCFDA fluorescence, and ceramide abundance. The effect of adarotene (9 µM) on annexin-V-binding was significantly blunted but not abolished by removal of extracellular Ca2+. Conclusions: Adarotene stimulates phospholipid scrambling of the erythrocyte cell membrane, an effect paralleled by and at least in part due to Ca2+ entry, oxidative stress and ceramide.

scholarly journals Ca2+ Entry, Oxidative Stress, Ceramide and Suicidal Erythrocyte Death Following Diosgenin Treatment

2016 ◽  
Vol 39 (4) ◽  
pp. 1626-1637 ◽  
Author(s):  
Morena Mischitelli ◽  
Mohamed Jemaà ◽  
Mustafa Almasry ◽  
Caterina Faggio ◽  
Florian Lang
Keyword(s):  
Oxidative Stress ◽  
Cell Membrane ◽  
Haemoglobin Concentration ◽  
Annexin V ◽  
Cellular Mechanisms ◽  
Forward Scatter ◽  
Erythrocyte Surface ◽  
Suicidal Death ◽  
Phosphatidylserine Translocation ◽  
Surface Signaling

Background/Aims: The bioactive steroid sapogenin diosgenin is considered for a wide variety of applications including treatment of malignancy. The substance counteracts tumor growth in part by stimulating apoptosis of tumor cells. Similar to apoptosis of nucleated cells, erythrocytes may enter suicidal death or eryptosis, which is characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Signaling involved in the stimulation of eryptosis includes increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress and ceramide. The present study explored, whether diosgenin induces eryptosis and, if so, to decipher cellular mechanisms involved. Methods: Flow cytometry was employed to estimate phosphatidylserine exposure at the cell surface from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, ROS formation from DCF dependent fluorescence, and ceramide abundance utilizing specific antibodies. Hemolysis was quantified by determination of haemoglobin concentration in the supernatant. Results: A 48 hours exposure of human erythrocytes to diosgenin significantly increased the percentage of annexin-V-binding cells (≥ 5 µM), significantly decreased forward scatter (15 µM), significantly increased Fluo3-fluorescence (≥ 10 µM), significantly increased DCF fluorescence (15 µM), significantly increased ceramide abundance (15 µM) and significantly increased hemolysis (15 µM). The effect of diosgenin (15 µM) on annexin-V-binding was significantly blunted but not abolished by removal of extracellular Ca2+. Conclusions: Diosgenin stimulates eryptosis with erythrocyte shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect paralleled by and at least in part due to Ca2+ entry, oxidative stress and ceramide.

scholarly journals Triggering of Erythrocyte Cell Membrane Scrambling by Emodin

2016 ◽  
Vol 40 (1-2) ◽  
pp. 91-103 ◽  
Author(s):  
Morena Mischitelli ◽  
Mohamed Jemaà ◽  
Mustafa Almasry ◽  
Caterina Faggio ◽  
Florian Lang
Keyword(s):  
Oxidative Stress ◽  
Cell Membrane ◽  
Annexin V ◽  
Microbial Infection ◽  
Cellular Mechanisms ◽  
Forward Scatter ◽  
Erythrocyte Surface ◽  
Suicidal Death ◽  
Phosphatidylserine Translocation ◽  
Surface Signaling

Background/Aims: The natural anthraquinone derivative emodin (1,3,8-trihydroxy-6-methylanthraquinone) is a component of several Chinese medicinal herbal preparations utilized for more than 2000 years. The substance has been used against diverse disorders including malignancy, inflammation and microbial infection. The substance is effective in part by triggering suicidal death or apoptosis. Similar to apoptosis of nucleated cells erythrocytes may enter suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Signaling involved in the triggering of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress and ceramide. The present study aimed to test, whether emodin induces eryptosis and, if so, to elucidate underlying cellular mechanisms. Methods: Phosphatidylserine abundance at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, ROS formation from DCFDA dependent fluorescence, and ceramide abundance utilizing specific antibodies. Results: Exposure of human erythrocytes for 48 hours to emodin (≥ 10 µM) significantly increased the percentage of annexin-V-binding cells, and at higher concentrations (≥ 50 µM) significantly increased forward scatter. Emodin significantly increased Fluo3-fluorescence (≥ 10 µM), DCFDA fluorescence (75 µM) and ceramide abundance (75 µM). The effect of emodin on annexin-V-binding was significantly blunted but not abolished by removal of extracellular Ca2+. Conclusions: Emodin triggers phospholipid scrambling of the erythrocyte cell membrane, an effect at least in part due to stimulation of Ca2+ entry and paralleled by oxidative stress and ceramide appearance at the erythroctye surface.

scholarly journals Stimulation of Suicidal Erythrocyte Death by Rottlerin

2016 ◽  
Vol 40 (3-4) ◽  
pp. 558-566 ◽  
Author(s):  
Morena Mischitelli ◽  
Mohamed Jemaà ◽  
Mustafa Almasry ◽  
Caterina Faggio ◽  
Florian Lang
Keyword(s):  
Cell Membrane ◽  
Haemoglobin Concentration ◽  
Annexin V ◽  
Decisive Role ◽  
Forward Scatter ◽  
Erythrocyte Surface ◽  
Suicidal Death ◽  
Phosphatidylserine Translocation ◽  
Surface Signaling ◽  
Stimulation Of

Background/Aims: The phytochemical polyphenol rottlerin is a potent activator of diverse Ca2+ -sensitive K+ channels. Those channels play a decisive role in the execution of eryptosis, the suicidal death of erythrocytes, which is characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Signaling involved in the stimulation of eryptosis includes increase of cytosolic Ca2+ activity ([Ca2+]i) and ceramide. The present study explored, whether rottlerin induces eryptosis and, if so, to test for the involvement of Ca2+ entry and ceramide. Methods: Flow cytometry was employed to estimate phosphatidylserine exposure at the cell surface from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, and ceramide abundance utilizing specific antibodies. Hemolysis was quantified by determination of haemoglobin concentration in the supernatant. Results: A 48 hours exposure of human erythrocytes to rottlerin (1 - 5 µM) significantly increased the percentage of annexin-V-binding cells, an effect paralleled by significant decrease of forward scatter. Up to 5 µM rottlerin failed to significantly increase average Fluo3-fluorescence. Rottlerin (5 µM) did, however, significantly increase the ceramide abundance. Rottlerin (5 µM) further significantly increased hemolysis. The effect of rottlerin (5 µM) on annexin-V-binding was virtually abolished by removal of extracellular Ca2+. Conclusions: Rottlerin stimulates eryptosis with erythrocyte shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect paralleled by and at least in part due to Ca2+ entry and ceramide.

scholarly journals Stimulation of Eryptosis, the Suicidal Erythrocyte Death, by Costunolide

2018 ◽  
Vol 50 (6) ◽  
pp. 2283-2295 ◽  
Author(s):  
Madeline Fink ◽  
Abdulla Al Mamun Bhuyan ◽  
Nefeli Zacharopoulou ◽  
Florian Lang
Keyword(s):  
Oxidative Stress ◽  
Cell Membrane ◽  
Annexin V ◽  
Cell Shrinkage ◽  
Forward Scatter ◽  
Erythrocyte Surface ◽  
Suicidal Death ◽  
Phosphatidylserine Translocation ◽  
Ros Formation ◽  
Binding Cell

Background/Aims: The sesquiterpene lactone Costunolide is effective against various disorders including inflammation and malignancy. The substance is effective in part by triggering suicidal death or apoptosis of tumor cells. Mechanisms involved include altered function of transcription factors and mitochondria. Erythrocytes lack nuclei and mitochondria but are – in analogy to apoptosis of nucleated cells – able to enter suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress and ceramide. The present study explored, whether Costunolide induces eryptosis and, if so, to shed light on the mechanisms involved. Methods: Phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, reactive oxygen species (ROS) formation from 2’,7’-dichlorodihydrofluorescein (DCF)-dependent fluorescence, and ceramide abundance utilizing specific antibodies. Results: A 48 hours exposure of human erythrocytes to Costunolide (15 µg/ml) significantly enhanced the percentage of annexin-V-binding cells, significantly decreased forward scatter and significantly increased Fluo3-fluorescence, DCF-fluorescence, and ceramide abundance. The effect of Costunolide on annexin-V-binding was significantly blunted by removal of extracellular Ca2+. Conclusion: Costunolide triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect at least in part due to Ca2+ entry and paralleled by oxidative stress and ceramide formation.

scholarly journals Triggering of Suicidal Erythrocyte Death by Exemestane

2017 ◽  
Vol 42 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Abdulla Al Mamun Bhuyan ◽  
Rosi Bissinger ◽  
Hang Cao ◽  
Florian Lang
Keyword(s):  
Oxidative Stress ◽  
Cell Membrane ◽  
Kinase Inhibitor ◽  
Annexin V ◽  
Forward Scatter ◽  
Erythrocyte Surface ◽  
Phosphatidylserine Translocation ◽  
Surface Signaling ◽  
Estrogen Biosynthesis ◽  
Stimulation Of

Background/Aims: The steroidal aromatase inactivator exemestane blocks estrogen biosynthesis and is thus employed for the prevention and treatment of breast cancer. Exemestane is in part effective by stimulation of suicidal cell death or apoptosis. Side effects of exemestane treatment include anemia. At least in theory, exemestane induced anemia could be secondary to stimulation of suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Signaling involved in the stimulation of eryptosis includes increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress, ceramide, several kinases and caspases. The present study explored, whether exemestane is able to trigger eryptosis and, if so, to shed some light on the signaling involved. Methods: Flow cytometry was employed to quantify phosphatidylserine exposure at the cell surface from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, reactive oxygen species (ROS) abundance from DCF fluorescence, and ceramide abundance utilizing specific antibodies. Results: A 48 hours exposure of human erythrocytes to exemestane (≥ 10 µg/ml) significantly increased the percentage of annexin-V-binding cells without significantly modifying forward scatter. Exemestane significantly increased Fluo3-fluorescence (10 and 20, but not 40 µg/ml), DCF fluorescence (40 µg/ml), and ceramide abundance (40 µg/ml). The effect of exemestane (40 µg/ml) on annexin-V-binding was significantly blunted by antioxidant N-acetylcysteine (1mM), but was not significantly modified by removal or increase of extracellular Ca2+, by p38 kinase inhibitor SB203580 (2 µM), casein kinase inhibitor D4476 (10 µM) and caspase inhibitor zVAD (10 µM). Conclusions: Exemestane triggers phospholipid scrambling of the erythrocyte cell membrane, an effect paralleled by enhanced [Ca2+]i, oxidative stress, and increased ceramide abundance.

scholarly journals Stimulating Effect of Terfenadine on Erythrocyte Cell Membrane Scrambling

2016 ◽  
Vol 38 (4) ◽  
pp. 1425-1434 ◽  
Author(s):  
Elena Signoretto ◽  
Michela Castagna ◽  
Abdulla Al Mamun Bhuyan ◽  
Florian Lang
Keyword(s):  
Cell Membrane ◽  
Human Erythrocyte ◽  
Haemoglobin Concentration ◽  
Annexin V ◽  
Human Erythrocytes ◽  
Forward Scatter ◽  
Erythrocyte Surface ◽  
Suicidal Death ◽  
Phosphatidylserine Translocation ◽  
Surface Signaling

Background/Aims: The antihistaminic drug Terfenadine may trigger apoptosis of tumor cells, an effect unrelated to its effect on histamine receptors. Similar to apoptosis of nucleated cells, erythrocytes may enter eryptosis, the suicidal death of erythrocytes characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Signaling triggering eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress, and ceramide. The present study explored, whether Terfenadine is capable to trigger eryptosis. Methods: Flow cytometry was employed to estimate phosphatidylserine abundance at the erythrocyte surface from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, abundance of reactive oxygen species (ROS) from 2′,7′-dichlorodihydrofluorescein (DCF) diacetate dependent fluorescence, and ceramide abundance at the human erythrocyte surface utilizing specific antibodies. Hemolysis was quantified from haemoglobin concentration in the supernatant. Results: A 48 hours exposure of human erythrocytes to Terfenadine (≥ 5 µM) significantly increased the percentage of annexin-V-binding cells and triggered hemolysis without significantly modifying the average forward scatter. Terfenadine (7.5 µM) significantly increased Fluo3-fluorescence, but did not significantly modify DCF fluorescence or ceramide abundance. The effect of Terfenadine on annexin-V-binding was significantly blunted but not abolished by removal of extracellular Ca2+. Exposure of human erythrocytes to Ca2+ ionophore ionomycin (1 µM, 15 min) triggered annexin-V-binding, an effect augmented by Terfenadine pretreatment (10 µM, 48 hours). Conclusions: Terfenadine triggers phospholipid scrambling of the human erythrocyte cell membrane, an effect in part due to entry of extracellular Ca2+ and in part due to sensitizing human erythrocyte cell membrane scrambling to Ca2+.

scholarly journals Oxaliplatin Induced Suicidal Death of Human Erythrocytes

2015 ◽  
Vol 37 (6) ◽  
pp. 2393-2404 ◽  
Author(s):  
Antonella Fazio ◽  
Marilena Briglia ◽  
Caterina Faggio ◽  
Kousi Alzoubi ◽  
Florian Lang
Keyword(s):  
Cell Membrane ◽  
Annexin V ◽  
Human Erythrocytes ◽  
Cell Shrinkage ◽  
Forward Scatter ◽  
Erythrocyte Surface ◽  
Suicidal Death ◽  
Phosphatidylserine Translocation ◽  
Ros Formation ◽  
Binding Cell

Background/Aims: The alkylating drug oxaliplatin is widely used for chemotherapy of malignancy. Oxaliplatin is effective by inducing both, necrosis and apoptosis. Similar to necrosis or apoptosis of nucleated cells, erythrocytes may enter hemolysis, which is apparent from hemoglobin release or eryptosis, which is characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include oxidative stress and/or Ca2+ entry with increase of cytosolic Ca2+ activity ([Ca2+]i). The present study explored, whether and how oxaliplatin induces eryptosis. Methods: Phosphatidylserine exposure at the cell surface was quantified utilizing annexin-V-binding, cell volume estimated from forward scatter, hemolysis deduced from hemoglobin release, [Ca2+]i determined utilizing Fluo-3 fluorescence, and reactive oxygen species (ROS) abundance visualized using 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) dependent fluorescence. Results: A 48 hours exposure of human erythrocytes to oxaliplatin (10 µg/ml) significantly increased the percentage of annexin-V-binding cells, significantly decreased forward scatter, significantly increased Fluo-3 fluorescence, and significantly increased DCFDA fluorescence. The effect of oxaliplatin on annexin-V-binding and forward scatter was rather augmented by removal of extracellular Ca2+, but was significantly blunted in the presence of the antioxidant N-acetyl-cysteine (1 mM). Conclusions: Oxaliplatin triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect partially dependent on ROS formation.

scholarly journals Stimulation of Suicidal Erythrocyte Death by Tafenoquine

2016 ◽  
Vol 39 (6) ◽  
pp. 2464-2476 ◽  
Author(s):  
Abdulla Al Mamun Bhuyan ◽  
Rosi Bissinger ◽  
Katja Stockinger ◽  
Florian Lang
Keyword(s):  
Oxidative Stress ◽  
Cell Membrane ◽  
Annexin V ◽  
Casein Kinase ◽  
Cell Shrinkage ◽  
Cellular Mechanisms ◽  
Forward Scatter ◽  
Suicidal Death ◽  
Phosphatidylserine Translocation ◽  
Stimulation Of

Background/Aims: The 8-aminoquinoline tafenoquine has been shown to be effective against Plasmodia, Leishmania and Trypanosoma. The substance is at least in part effective by triggering apoptosis of the parasites. Similar to apoptosis, erythrocytes may enter suicidal death or eryptosis, which is characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Signaling involved in the regulation of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress, ceramide, zVAD sensitive caspases, SB203580 sensitive p38 kinase, staurosporine sensitive protein kinase C as well as D4476 sensitive casein kinase. The present study explored, whether tafenoquine induces eryptosis and aimed to possibly identify cellular mechanisms involved. Methods: Flow cytometry was employed to estimate phosphatidylserine exposure at the cell surface from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, ROS formation from 2′,7′-dichlorodihydrofluorescein diacetate (DCFDA) dependent fluorescence, and ceramide abundance utilizing specific antibodies. Results: A 48 hours exposure of human erythrocytes to tafenoquine (500 ng/ml) significantly increased the percentage of annexin-V-binding cells, significantly decreased forward scatter, significantly increased Fluo3-fluorescence, and significantly increased DCFDA fluorescence. Tafenoquine did not significantly modify ceramide abundance. The effect of tafenoquine on annexin-V-binding was significantly blunted but not abolished by removal of extracellular Ca2+. The effect of tafenoquine on annexin-V-binding was not significantly blunted by zVAD (10 µM), SB203580 (2 µM) or staurosporine (1 µM). The effect of tafenoquine on annexin-V-binding was significantly blunted but not abolished by D4476 (10 µM). Conclusions: Tafenoquine triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect at least in part due to stimulation of Ca2+ entry, oxidative stress and possibly activation of casein kinase.

scholarly journals Saquinavir Induced Suicidal Death of Human Erythrocytes

2015 ◽  
Vol 37 (5) ◽  
pp. 1973-1982 ◽  
Author(s):  
Sabrina Waibel ◽  
Rosi Bissinger ◽  
Ghada Bouguerra ◽  
Salem Abbès ◽  
Florian Lang
Keyword(s):  
Cell Membrane ◽  
Annexin V ◽  
Hiv Infections ◽  
Human Erythrocytes ◽  
Cell Shrinkage ◽  
Forward Scatter ◽  
Erythrocyte Surface ◽  
Suicidal Death ◽  
Phosphatidylserine Translocation ◽  
Ros Formation

Background/Aims: The antiretroviral protease inhibitor saquinavir is used for the treatment of HIV infections. Effects of saquinavir include induction of apoptosis, the suicidal death of nucleated cells. Saquinavir treatment may further lead to anemia. In theory, anemia could result from accelerated erythrocyte loss by enhanced suicidal erythrocyte death or eryptosis, which is characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Stimulators of eryptosis include Ca2+ entry with increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress with increase of reactive oxygen species (ROS) and ceramide. The present study explored, whether and how saquinavir induces eryptosis. Methods: To this end, flow cytometry was employed to estimate erythrocyte volume from forward scatter, phosphatidylserine exposure at the cell surface from annexin-V-binding, [Ca2+]i from Fluo3-fluorescence, ROS abundance from DCFDA fluorescence and ceramide abundance utilizing specific antibodies. Results: A 48 hours exposure of human erythrocytes to saquinavir significantly decreased forward scatter (≥ 5 µg/ml), significantly increased the percentage of annexin-V-binding cells (≥ 10 µg/ml), significantly increased Fluo3-fluorescence (15 µg/ml), significantly increased DCFDA fluorescence (15 µg/ml), but did not significantly modify ceramide abundance. The effect of saquinavir on annexin-V-binding was significantly blunted, but not abolished by removal of extracellular Ca2+. Conclusions: Saquinavir triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect in part due to stimulation of ROS formation and Ca2+ entry.

scholarly journals Taurolidine Sensitivity of Eryptosis, the Suicidal Erythrocyte Death

2018 ◽  
Vol 51 (2) ◽  
pp. 501-512 ◽  
Author(s):  
Madeline Fink ◽  
Abdulla  Al Mamun Bhuyan ◽  
Nefeli Zacharopoulou ◽  
Florian Lang
Keyword(s):  
Cell Membrane ◽  
Annexin V ◽  
Cell Shrinkage ◽  
Cellular Mechanisms ◽  
Forward Scatter ◽  
Erythrocyte Surface ◽  
Suicidal Death ◽  
Phosphatidylserine Translocation ◽  
Surface Signaling ◽  
Induced Apoptosis

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. Methods: 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. Results: 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+. Conclusion: 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.

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