scholarly journals Inhibition of Erythrocyte Cell Membrane Scrambling by ASP3026

2017 ◽  
Vol 43 (2) ◽  
pp. 507-517 ◽  
Author(s):  
Abdulla Al Mamun Bhuyan ◽  
Rosi Bissinger ◽  
Hang Cao ◽  
Florian Lang
Keyword(s):  
Oxidative Stress ◽  
Cell Membrane ◽  
Cell Surface ◽  
Small Cell Lung Carcinoma ◽  
Annexin V ◽  
Forward Scatter ◽  
Energy Depletion ◽  
Cell Lung Carcinoma ◽  
Anaplastic Lymphoma ◽  
And Oxidative Stress

Background/Aims: The anaplastic lymphoma kinase (ALK) inhibitor ASP3026 is in clinical development for the treatment of ALK expressing non-small cell lung carcinoma (NSCLC). ASP3026 is in part effective by inducing apoptosis of tumor cells. Erythrocytes lack mitochondria and nuclei, key organelles in the execution of apoptosis, but are nevertheless able to enter suicidal death or eryptosis, which is characterized by cell membrane scrambling with phosphatidylserine translocation to the cell surface and by cell shrinkage. Eryptosis is triggered by cell stress, such as energy depletion, hyperosmotic shock, oxidative stress and excessive increase of cytosolic Ca2+ activity ([Ca2+]i). The present study explored, whether ASP3026 impacts on eryptosis. Methods: Human erythrocytes have been exposed to energy depletion (glucose withdrawal for 48 hours), oxidative stress (addition of 0.3 mM tert-butylhydroperoxide [tBOOH] for 50 min) or Ca2+ loading with Ca2+ ionophore ionomycin (1 µM for 60 min) in absence and presence of ASP3026 (1-4 µg/ml). Flow cytometry was employed to quantify phosphatidylserine exposure at the cell surface from annexin-V-binding, and cell volume from forward scatter. Results: Treatment with ASP3026 alone did not significantly modify annexin-V-binding or forward scatter. Energy depletion, oxidative stress and ionomycin, all markedly and significantly increased the percentage of annexin-V-binding erythrocytes, and decreased the forward scatter. ASP3026 significantly blunted the effect of energy depletion and oxidative stress, but not of ionomycin on annexin-V-binding. ASP3026 did not significantly influence the effect of any maneuver on forward scatter. Conclusions: ASP3026 is a novel inhibitor of erythrocyte cell membrane scrambling following energy depletion and oxidative stress.

scholarly journals Sonidegib, a Novel Inhibitor of Suicidal Erythrocyte Death

2018 ◽  
Vol 47 (4) ◽  
pp. 1352-1364
Author(s):  
Abdulla Al Mamun Bhuyan ◽  
Itishri Sahu ◽  
Hang Cao ◽  
Florian Lang
Keyword(s):  
Oxidative Stress ◽  
Cell Membrane ◽  
Cell Surface ◽  
Annexin V ◽  
Hemoglobin Concentration ◽  
Cell Stress ◽  
Forward Scatter ◽  
Energy Depletion ◽  
Hyperosmotic Shock ◽  
And Oxidative Stress

Background/Aims: The Hedgehog pathway disrupting drug sonidegib is used in the treatment of basal cell carcinoma. Side effects of sonidegib include anemia, which could result either from impaired erythropoiesis or from loss of erythrocytes e.g. due to suicidal erythrocyte death or eryptosis, which is characterized by cell membrane scrambling with phosphatidylserine translocation to the cell surface and by cell shrinkage. Eryptosis is stimulated by cell stress, including energy depletion, hyperosmotic shock, oxidative stress and excessive increase of cytosolic Ca2+ activity ([Ca2+]i). The present study explored, whether sonidegib exerts an effect on eryptosis. Methods: Human erythrocytes have been treated with energy depletion (glucose withdrawal for 48 hours), hyperosmotic shock (addition of 550 mM sucrose for 6 hours), oxidative stress (addition of 0.3 mM tert-butylhydroperoxide [tBOOH] for 50 min) or Ca2+ ionophore ionomycin (1 µM for 60 min) in absence and presence of sonidegib (2-6 µg/ ml). After treatment flow cytometry was employed to quantify phosphatidylserine exposure at the cell surface from annexin-V-binding, and cell volume from forward scatter. Hemolysis was estimated from the hemoglobin concentration in the supernatant. Results: In the absence of cell stress exposure to sonidegib did not significantly modify annexin-V-binding or forward scatter, but triggered hemolysis. Energy depletion, hyperosmotic shock, oxidative stress and ionomycin, all markedly and significantly increased the percentage of annexin-V-binding erythrocytes, and decreased the forward scatter. Sonidegib significantly blunted the effect of energy depletion, hyperosmotic shock, and oxidative stress, but not of ionomycin on annexin-V-binding. Sonidegib further significantly blunted the effect of energy depletion, but not of hyperosmotic shock, oxidative stress, and ionomycin on forward scatter. Conclusions: Sonidegib is a novel inhibitor of erythrocyte cell membrane scrambling following energy depletion, hyperosmotic shock and oxidative stress.

scholarly journals Stimulation of Suicidal Erythrocyte Death by Ceritinib-Treatment of Human Erythrocytes

2016 ◽  
Vol 40 (5) ◽  
pp. 1129-1140 ◽  
Author(s):  
Abdulla Al Mamun Bhuyan ◽  
Elena Signoretto ◽  
Rosi Bissinger ◽  
Florian Lang
Keyword(s):  
Cell Membrane ◽  
Small Cell Lung Carcinoma ◽  
Annexin V ◽  
Human Erythrocytes ◽  
Cell Shrinkage ◽  
Forward Scatter ◽  
Cell Lung Carcinoma ◽  
Casein Kinase 1 ◽  
Anaplastic Lymphoma ◽  
Stimulation Of

Background/Aims: The anaplastic lymphoma kinase (ALK) inhibitor ceritinib is utilized for the treatment of ALK positive non-small cell lung carcinoma. Side effects of the drug include decrease of blood hemoglobin concentration. Possible causes of anemia include stimulation of 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, ceramide, staurosporine sensitive protein kinase C, SB203580 sensitive p38 kinase, D4476 sensitive casein kinase 1, and zVAD sensitive caspases. The present study explored, whether ceritinib induces eryptosis and, if so, to shed light on the cellular 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, ROS formation from DCFDA dependent fluorescence, and ceramide abundance utilizing specific antibodies. Results: A 48 hours exposure of human erythrocytes to ceritinib (1 µg/ml) significantly increased the percentage of annexin-V-binding cells, significantly decreased forward scatter, significantly increased Fluo3-fluorescence, but did not significantly modify DCFDA fluorescence or ceramide abundance. The effect of ceritinib on annexin-V-binding was significantly blunted but not abolished by removal of extracellular Ca2+, by the kinase inhibitors staurosporine (1 µM), SB203580 (2 µM) and D4476 (10 µM), as well as by caspase inhibitor zVAD (10 µM). Conclusions: Ceritinib triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect at least in part due to Ca2+ entry, as well as activation of kinases and Caspases.

scholarly journals Inhibition of Suicidal Erythrocyte Death by Volasertib

2017 ◽  
Vol 43 (4) ◽  
pp. 1472-1486 ◽  
Author(s):  
Abdulla Al Mamun Bhuyan ◽  
A.K.M. Ashiqul Haque ◽  
Itishri Sahu ◽  
Hang Cao ◽  
Michael S.D. Kormann ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Membrane ◽  
Cell Surface ◽  
Annexin V ◽  
K562 Cells ◽  
Forward Scatter ◽  
Energy Depletion ◽  
Hyperosmotic Shock ◽  
Suicidal Death ◽  
Phosphatidylserine Translocation

Background/Aims: The Polo-like kinase 1 (Plk1) inhibitor volasertib is used in the treatment of malignancy. Volasertib is partially effective by triggering suicidal death or apoptosis of tumor cells. Similar to apoptosis of nucleated cells, erythrocytes may enter suicidal cell death or eryptosis, which is characterized by cell membrane scrambling with phosphatidylserine translocation to the cell surface and by cell shrinkage. Stimulators of eryptosis include energy depletion, hyperosmotic shock, oxidative stress and excessive increase of cytosolic Ca2+ activity ([Ca2+]i). The present study explored, whether volasertib impacts on eryptosis. Methods: Human erythrocytes have been exposed to energy depletion (glucose withdrawal for 48 hours), hyperosmotic shock (addition of 550 mM sucrose for 6 hours), oxidative stress (addition of 0.3 mM tert-butylhydroperoxide [tBOOH] for 50 min) or Ca2+ ionophore ionomycin (1 µM for 60 min) in absence and presence of volasertib (0.5-1.5 µg/ml) and 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 from 2’,7’-dichlorodihydrofluorescein diacetate (DCFDA) fluorescence and ceramide abundance utilizing antibodies. For comparison, annexin-V-binding and forward scatter were determined following a 48 hours exposure of human leukemic K562 cells in RPMI-1640 medium to volasertib. Results: Treatment with volasertib alone did not significantly modify annexin-V-binding or forward scatter in mature erythrocytes. Energy depletion, hyperosmotic shock, oxidative stress and ionomycin, all markedly and significantly increased the percentage of annexin-V-binding erythrocytes, and decreased the forward scatter. Volasertib significantly blunted the effect of energy depletion and hyperosmotic shock, but not of oxidative stress and ionomycin on annexin-V-binding. Volasertib did not significantly influence the effect of any maneuver on forward scatter. In K562 cells, volasertib enhanced annexin-V-binding and decreased the forward scatter. Conclusions: Volasertib is a novel inhibitor of erythrocyte cell membrane scrambling following energy depletion and hyperosmotic shock, effects contrasting the stimulation of K562 cell apoptosis.

scholarly journals Inhibition of Erythrocyte Cell Membrane Scrambling Following Energy Depletion and Hyperosmotic Shock by Alectinib

2018 ◽  
Vol 51 (5) ◽  
pp. 1996-2009 ◽  
Author(s):  
Abdulla  Al Mamun Bhuyan ◽  
Florian Lang
Keyword(s):  
Oxidative Stress ◽  
Cell Membrane ◽  
Annexin V ◽  
Glucose Deprivation ◽  
Forward Scatter ◽  
Energy Depletion ◽  
Hyperosmotic Shock ◽  
Anaplastic Lymphoma ◽  
Suicidal Death ◽  
Alk Positive

Background/Aims: The anaplastic lymphoma kinase (ALK) inhibitor alectinib is clinically used for the treatment of ALK positive non-small-cell lung cancer. At least in part the substance is effective by triggering suicidal death or apoptosis of tumor cells. Erythrocytes are lacking mitochondria and nuclei, key organelles of apoptosis but are, similar to apoptosis of nucleated cells, able to enter suicidal erythrocyte death or eryptosis. Stimulators of eryptosis include energy depletion, hyperosmotic shock, oxidative stress, and increase of cytosolic Ca2+ activity ([Ca2+]i). The present study explored, whether alectinib influences eryptosis. Methods: Flow cytometry was employed to quantify phosphatidylserine exposure at the cell surface from annexin-V-binding and cell volume from forward scatter. Measurements were made without or with energy depletion (glucose deprivation for 48 hours), hyperosmotic shock (+550mM sucrose for 6 hours), oxidative stress (50 min exposure to 0.3 mM tert-butylhydroperoxide), and Ca2+ loading (60 minutes treatment with 1 µM Ca2+ ionophore ionomycin). Results: A 48 hours exposure of human erythrocytes to alectinib (150-600 ng/ml) did not significantly modify the percentage of annexin-V-binding cells and forward scatter. Energy depletion, hyperosmotic shock, oxidative stress and Ca2+ loading were each followed by profound and significant increase of the percentage annexin-V-binding erythrocytes and a significant decrease of forward scatter. The effects of energy depletion and hyperosmotic shock, but not of oxidative stress or Ca2+ loading on annexin-V-binding were significantly blunted in the presence of alectinib (150-600 ng/ml). In none of the conditions was forward scatter significantly modified by alectinib. Conclusion: Alectinib inhibits cell membrane scrambling following energy depletion and hyperosmotic shock.

scholarly journals Stimulation of Eryptosis by Afatinib

2018 ◽  
Vol 47 (3) ◽  
pp. 1259-1273 ◽  
Author(s):  
Abdulla Al Mamun Bhuyan ◽  
Florian Lang
Keyword(s):  
Oxidative Stress ◽  
Cell Membrane ◽  
Kinase Inhibitor ◽  
Small Cell Lung Carcinoma ◽  
Growth Factor Receptor ◽  
Annexin V ◽  
Tumor Cell Death ◽  
Forward Scatter ◽  
Cell Lung Carcinoma ◽  
Stimulation Of

Background/Aims: The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor afatinib is primarily utilized for the treatment of non-small cell lung carcinoma. The drug is at least partially effective by triggering suicidal tumor cell death. Side effects of afatinib treatment include anemia. At least in theory, afatinib 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 potentially stimulating eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i), induction of oxidative stress, and increase of ceramide abundance. The present study explored, whether afatinib induces eryptosis and, if so, whether its effect involves Ca2+ entry, oxidative stress, and/or ceramide. 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 DCFDA dependent fluorescence, and ceramide abundance utilizing specific antibodies. Results: A 48 hours exposure of human erythrocytes to afatinib (≥ 4 µg/ml) significantly increased the percentage of annexin-V-binding cells and significantly decreased forward scatter. Afatinib significantly increased Fluo3-fluorescence, DCFDA fluorescence and ceramide abundance. The effect of afatinib on annexin-V-binding and forward scatter was significantly blunted by removal of extracellular Ca2+. Conclusions: Afatinib triggers phospholipid scrambling of the erythrocyte cell membrane, an effect at least in part due to Ca2+ entry, oxidative stress, and ceramide.

scholarly journals Inhibition of Suicidal Erythrocyte Death by Reversine

2017 ◽  
Vol 41 (6) ◽  
pp. 2363-2373 ◽  
Author(s):  
Mohamed Jemaà ◽  
Myriam Fezai ◽  
Florian Lang
Keyword(s):  
Oxidative Stress ◽  
Annexin V ◽  
Glucose Deprivation ◽  
Cell Swelling ◽  
Forward Scatter ◽  
Energy Depletion ◽  
Adenosine Receptor Antagonist ◽  
Tert Butylhydroperoxide ◽  
A3 Adenosine Receptor ◽  
And Oxidative Stress

Background/Aims: The A3 adenosine receptor antagonist reversine (2-(4-morpholinoanilino)-6-cyclohexylaminopurine) influences cellular differentiation, inhibits cell proliferation, induces cell-cycle arrest, triggers apoptosis, causes cell swelling with polyploidy and stimulates autophagy. The effect on apoptosis involves mitochondria and caspases. Erythrocytes are lacking mitochondria but express caspases and are, similar to apoptosis of nucleated cells, able to enter suicidal erythrocyte death or eryptosis. Stimulators of eryptosis include increase of cytosolic Ca2+ activity ([Ca2+]i), energy depletion and oxidative stress. The present study explored, whether reversine influences eryptosis. Methods: Flow cytometry was employed to quantify phosphatidylserine exposure at the cell surface from annexin-V-binding and cell volume from forward scatter. Measurements were made without or with energy depletion (glucose deprivation for 48 hours), Ca2+ loading (30 minutes treatment with 1 µM Ca2+ ionophore ionomycin), or oxidative stress (15 min exposure to 0.3 mM tert-butylhydroperoxide). Results: A 48 hours exposure of human erythrocytes to reversine (1-10 µM) did not significantly modify the percentage of annexin-V-binding cells and forward scatter. Energy depletion, Ca2+ loading, and oxidative stress were each followed by profound and significant increase of the percentage annexin-V-binding erythrocytes and a significant decrease of forward scatter. The effects of each, Ca2+ loading, energy depletion and oxidative stress on annexin-V-binding were significantly blunted in the presence of reversine (1-10 µM). The effect of ionomycin, but not the effects of energy depletion and oxidative stress on forward scatter were again significantly blunted in the presence of reversine (≥1 µM]. Conclusions: Reversine is a powerful inhibitor of cell membrane scrambling following energy depletion, Ca2+ loading and oxidative stress.

scholarly journals Inhibition by Teriflunomide of Erythrocyte Cell Membrane Scrambling Following Energy Depletion, Oxidative Stress and Ionomycin

2016 ◽  
Vol 39 (5) ◽  
pp. 1877-1890 ◽  
Author(s):  
Jens Zierle ◽  
Rosi Bissinger ◽  
Florian Lang
Keyword(s):  
Oxidative Stress ◽  
Cell Membrane ◽  
Annexin V ◽  
Forward Scatter ◽  
Energy Depletion ◽  
Pyrimidine Synthesis ◽  
Tert Butylhydroperoxide ◽  
Stress Energy ◽  
Erythrocyte Surface ◽  
Suicidal Death

Background/Aims: Teriflunomide, an inhibitor of pyrimidine synthesis and thus proliferation of activated T and B lymphocytes, is successfully used for treatment of inflammatory disease. Teriflunomide has further been shown to trigger apoptosis of tumor cells and has thus been considered for the treatment of malignancy. In analogy to apoptosis of nucleated cells, erythrocytes may enter suicidal death or eryptosis, which is characterized by cell shrinkage and phospholipid scrambling of the cell membrane with translocation of phosphatidylserine to the erythrocyte surface. Triggers of cell membrane scrambling include energy depletion, oxidative stress and increase of cytosolic Ca2+ activity ([Ca2+]i). The present study explored whether teriflunomide modifies eryptosis. Methods: Flow cytometry was employed to estimate phosphatidylserine abundance at the erythrocyte surface from annexin-V-binding, cell volume from forward scatter, and [Ca2+]i from Fluo3 fluorescence. Results: Oxidative stress (60 min exposure to 0.3 mM tert-butylhydroperoxide), energy depletion (removal of glucose for 48 hours), and exposure to the Ca2+ ionophore ionomycin (1 µM, 60 min) all increased annexin-V-binding, decreased forward scatter and enhanced Fluo3 fluorescence. Teriflunomide (5 µg/ml) did not significantly influence Fluo3 fluorescence, forward scatter and annexin-V-binding under control conditions but significantly blunted the increase of annexin-V-binding following oxidative stress, energy depletion and ionomycin exposure. Teriflunomide further blunted the increase of Fluo3 fluorescence following energy depletion, but did not significantly interfere with increase of Fluo3 fluorescence following oxidative stress and ionomycin exposure. Conclusion: Teriflunomide is a novel inhibitor of suicidal erythrocyte death.

scholarly journals Stimulated Suicidal Erythrocyte Death in Arteritis

2016 ◽  
Vol 39 (3) ◽  
pp. 1068-1077 ◽  
Author(s):  
Rosi Bissinger ◽  
Daniela S. Kempe-Teufel ◽  
Sabina Honisch ◽  
Syed M. Qadri ◽  
Elko Randrianarisoa ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Healthy Volunteers ◽  
Annexin V ◽  
Vascular Occlusion ◽  
Vascular Wall ◽  
Cellular Mechanisms ◽  
Forward Scatter ◽  
Erythrocyte Surface ◽  
Theory Result ◽  
And Oxidative Stress

Background/Aims: Arteritis is an inflammatory disease of the vascular wall leading to ischemia and vascular occlusion. Complications of arteritis include anemia, which could, at least in theory, result from suicidal erythrocyte death or eryptosis, which is characterized by erythrocyte shrinkage and phosphatidylserine (PS) exposure at the erythrocyte surface. Cellular mechanisms involved in the stimulation of eryptosis include increased cytosolic Ca2+-concentration ([Ca2+]i), oxidative stress and ceramide formation. The present study explored whether and how arteritis influences eryptosis. Methods: Blood was drawn from patients suffering from arteritis (n=17) and from healthy volunteers (n=21). PS exposure was estimated from annexin V-binding, erythrocyte volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, reactive oxygen species (ROS) from DCFDA fluorescence and ceramide abundance from FITC-conjugated antibody binding in flow cytometry. The patients suffered from anemia despite 2.8±0.4% reticulocytes. Results: The percentage of PS-exposing erythrocytes was significantly higher in patients (1.1±0.1%) than in healthy volunteers (0.3±0.1%). The increase in PS exposure was paralleled by increase in oxidative stress and [Ca2+]i but not by significant changes of ceramide abundance. Erythrocyte PS exposure and ROS production were significantly enhanced in erythrocytes exposed to patient plasma as compared to exposure to plasma from healthy volunteers. Conclusion: Arteritis is associated with enhanced eryptosis due to increased [Ca2+]i and oxidative stress. The eryptosis contributes to or even accounts for the anemia in those patients. As eryptotic erythrocytes adhere to endothelial cells of the vascular wall, they could impede microcirculation and thus contribute to vascular occlusion.

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 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.

Sign in / Sign up

Export Citation Format

Share Document