Fumagillin, a
cyclohexane isolated from fungus Aspergillus fumigatus, has anti-infective and anti-
cancer potency.
Fumagillin is at least partially effective by inducing suicidal death or apoptosis. In analogy to apoptosis of nucleated cells, eryptosis is the suicidal death of erythrocytes characterized by cell shrinkage and cell membrane scrambling with
phosphatidylserine exposure at the cell surface. Stimulators of eryptosis include increase of cytosolic Ca(2+)-activity ([Ca(2+)](i)) and
ceramide. The present study explored whether
fumagillin (5-100 μM) could stimulate eryptosis. To this end, [Ca(2+)](i) was estimated from Fluo3 fluorescence,
ceramide by utilizing specific
antibodies, cell volume from forward scatter,
phosphatidylserine exposure from
annexin V binding and
haemolysis from haemoglobin release. As a result, a 48-hr exposure to
fumagillin significantly increased [Ca(2+)](i) (≥10 μM), enhanced
ceramide abundance (100 μM), triggered
annexin V binding (≥10 μM) and decreased forward scatter (≥10 μM).
Fumagillin exposure was followed by slight but significant increase of
haemolysis. Removal of extracellular Ca(2+) significantly blunted but did not abolish the effect of
fumagillin (100 μM) on
annexin V binding. The present observations disclose a novel effect of
fumagillin, that is, stimulation of eryptosis, paralleled by Ca(2+) entry,
ceramide formation,
phosphatidylserine exposure and decrease of cell volume.