Effects of ATRA and synthetic retinoids on total TF antigen in NB4 cells. NB4 cells were incubated with 0.01 μmol/L ATRA (lane 2), Am80 (lane 4), Ch55 (lane 8), Ro25-7386 (lane 10), or 1 μmol/L Ro25-7386 (lane 11). Cells were also incubated with 1 μmol/L Ro41-5253 (lane 5), LE540 (lane 6), or both Ro41-5253 and LE540 (lane 7). One hour after the preincubation, 0.01 μmol/L ATRA (lane 3), Am80 (lanes 5, 6, and 7), or Ch55 (lane 9) was added for 24 hours. Lane 1 shows control without treatment.