Table 3

Selectivity of lipid-mediated cytotoxicity in U937 cells

TreatmentNoneOleoylethanolamineFumonisin B1
% Vehicle control
Vehicle3  ± 13  ± 15  ± 2
Ceramide42  ± 53-a 40  ± 53-a N.D.
Sphingosine69  ± 63-a N.D.66  ± 73-a

U937 cells were exposed to ceramide or sphingosine at equimolar levels (10 μm) in the presence of the ceramide acylhydrolase inhibitor oleoylethanolamine (100 μm) or the ceramide synthase inhibitor fumonisin B1 (100 μm). Cells exhibiting apoptotic DNA damage were visualized by fluorescence microscopy in fixed preparations after staining with FITC-dUTP in the presence of TdT as described in Materials and Methods. Values are expressed as percent untreated controls and reflect mean ± standard error of apoptotic cells (100 cells scored per treatment).

    • 3-a Increased vs.vehicle-treated controls (p < 0.01).