Geldanamycin-Induced Phosphatidylserine Translocation in the Erythrocyte Membrane

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.