Effects of sphinganine and GT-11 on dihydroceramides, ceramides and cytotoxicity.

<p><i>A</i>-<i>C</i>) CCRF-CEM cells were treated with sphinganine (4 µM, S) ± GT-11 (0.5 µM, G) for six hours and sphingolipids analyzed. <i>A</i>) Total dihydroceramides (DHCer) and ceramides (Cer) were normalized to drug/fatty acid vehicle-treated cells (control) and plotted as fold change (Y-axis). Error bar, propagated standard deviation. Individual dihydroceramides (<i>B</i>) and ceramides (<i>C</i>) were normalized to control and plotted as fold change (Z-axis). Dihydroceramides and ceramides are identified by acyl chain (x:y), where x is the number of carbons and y is the number of double bonds in the acyl chain (X-axis). Significant (<i>A</i>, <i>P</i> ≤ 0.001<i>; B</i> and C, P ≤ 0.05) fold changes between treatment and vehicle control levels are indicated by asterisks (*). <i>D</i>) Cytotoxicity of sphinganine and GT-11. Indicated cell lines were treated with sphinganine (0-4 µM) and/or GT-11 (0.5 µM). The cytotoxicity of GT-11-alone is represented by the sphinganine (0 µM) data point. Cytotoxicity assayed by DIMSCAN cytotoxicity assay at +48 hours. Data were normalized to vehicle-treated control and plotted as Survival Fraction (Y-axis). Error bar, SEM. Sphinganine + GT-11 resulted in significantly increased (<i>P</i> ≤ 0.001) cytotoxicity relative to sphinganine-only for all concentrations and across all cell lines.