ATRA and TO-901317 synergistically increase cellular cholesterol efflux. A) ATRA and TO-901317 increased ABCA1 dependent cholesterol efflux in Jurkat cells. Jurkat cells were treated with 5 μM ATRA, or 5 μM TO-901317 or 5 μM each of ATRA and TO-901317 for 24 hours along with radioactive cholesterol and cholesterol efflux to apo-A1 was estimated after 24 hours of incubation in cholesterol efflux medium. The results are presented as mean ± the standard deviation (SD; n = 3). ** p < 0.01 versus cells treated with DMSO. B-D) Cholesterol staining with Filipin III. 1G5 cells treated with 5 μM of ATRA and 1 μM of TO-901317 for 3 days and then incubated without (B, C) or with (D) 60 μM of water soluble cholesterol for 30 minutes at 37 °C. Cells were then fixed and stained with Filipin III as described in Methods. Scale bar 5 μm. C) The intensity of cholesterol staining in (B) was analyzed as described in Methods. The relative intensity compared to DMSO treatment was plotted. Data represents three individual fields with 40–60 cells per field. *p < 0.05; **p < 0.01.