FIGURE 4.

Effects of S1P on ceramide-induced autophagy. A, HL-60 cells were treated with 10 μm C₂-ceramide (C₂-Cer) for 1 h in AA(+) medium. Autophagosome formation was detected with LC-3 staining. Scale bar, 10 μm. B, cells were treated with the combination of C₂-Cer and S1P at various concentration for 30 min in AA(+) medium. After treatment with C₂-Cer and S1P at the indicated concentrations, autophagy was assessed by MDC incorporation under fluorescence microscopy and measured using MacSCOPE. Values are the mean ± S.D. from three independent experiments. *, p < 0.005; **, p < 0.05.