Fig. 4.

Treatment of P388D1 cells with an inhibitor of cholesterol trafficking, U18666A, preferentially inhibits cholesteryl ester accumulation, but does not inhibit 7KC-induced apoptosis. A, B: P388D1 cells were supplemented with or without U18666A (5 μM) for 1 h before supplementation with and without 7KC (10 μg/ml), as indicated. At this time, either [¹⁴C]cholesterol (0.5 μCi/ml) or [³H]7KC (1.0 °Ci/ml) was added to each well. After a 16 h incubation, total lipids were extracted, and the radioactivity incorporated into cholesteryl esters (A) and 7-ketocholesteryl esters (7KC esters; B) was determined. C: The effect of U18666A on the induction of caspase-3 activity in P388D1 cells. P388D1 cells were preincubated with U18666A (5 μM) for 1 h before a 16 h treatment with and without 7KC (10 μg/ml), as indicated. The cells were then harvested and caspase-3 activity was determined as described above. FLU, fluorescence light units. * P < 0.05 and ** P = 0.048 versus oxysterol-treated controls. Error bars represent standard deviation.