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Updated: May 4, 2026
Induction of Eryptosis in Red Blood Cells Using a Calcium Ionophore
Published on: January 21, 2020
Geldanamycin-induced phosphatidylserine translocation in the erythrocyte membrane
Kashif Jilani1, Syed M Qadri, Florian Lang
1Department of Physiology, Eberhard-Karls-University of Tuebingen, Tuebingen, Germany.
Background/Aims:
Geldanamycin, a benzoquinone ansamycin antibiotic, and its analogues induce apoptosis of tumor cells and are thus considered for the treatment of cancer. Similar to apoptosis of nucleated cells, erythrocytes may enter eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and by cell membrane scrambling with phosphatidylserine-exposure at the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca(2+)-concentration ([Ca(2+)]i) and formation of ceramide. The present study explored, whether geldanamycin modifies [Ca(2+)]i, ceramide formation, cell volume and phosphatidylserine abundance at the erythrocyte surface.
Methods:
Erythrocyte volume was estimated from forward scatter, phosphatidylserine-abundance from annexin V binding, hemolysis from hemoglobin release, ceramide formation from binding of fluorescent antibodies and [Ca(2+)]i from Fluo3-fluorescence.
Results:
A 48 hours exposure to geldanamycin significantly decreased forward scatter (≥ 5 µM), significantly increased annexin-V-binding (≥ 25 µM), but did not significantly modify Fluo3-fluorescence (up to 50 µM). The annexin-V-binding following geldanamycin treatment was not significantly modified by removal of extracellular Ca(2+) but was paralleled by significantly increased ceramide formation (50 µM).
Conclusions:
Geldanamycin stinulated eryptosis, an effect at least partially due to ceramide formation.
Insights
Geldanamycin, an anti-cancer drug, triggers eryptosis, a form of red blood cell death. This process involves increased ceramide formation and is independent of extracellular calcium, suggesting a novel mechanism for cancer therapy side effects.
Area of Science:
- Cell Biology
- Biochemistry
- Pharmacology
Background:
- Geldanamycin, a benzoquinone ansamycin antibiotic, shows anti-cancer properties by inducing tumor cell apoptosis.
- Eryptosis, or suicidal erythrocyte death, shares characteristics with apoptosis, including cell shrinkage and phosphatidylserine exposure.
- Elevated cytosolic calcium and ceramide formation are known triggers of eryptosis.
Purpose of the Study:
- To investigate the effects of geldanamycin on erythrocyte parameters.
- To determine if geldanamycin influences cytosolic calcium levels, ceramide formation, cell volume, and phosphatidylserine exposure in erythrocytes.
Main Methods:
- Erythrocyte volume assessed via forward scatter.
- Phosphatidylserine exposure measured by annexin V binding.
- Ceramide formation quantified using fluorescent antibodies.
- Cytosolic calcium levels determined using Fluo3-fluorescence.
Main Results:
- Geldanamycin exposure decreased erythrocyte forward scatter (cell volume) and increased annexin V binding (phosphatidylserine exposure) in a dose-dependent manner.
- Geldanamycin did not significantly alter cytosolic calcium levels.
- Increased ceramide formation was observed following geldanamycin treatment, independent of extracellular calcium.
Conclusions:
- Geldanamycin stimulates eryptosis in erythrocytes.
- Ceramide formation plays a significant role in geldanamycin-induced eryptosis.
- The findings suggest a potential mechanism for geldanamycin's effects on red blood cells.
