Modulation of the Hh pathway modifies the level of differentiation of K562 cells. (A-D) Cells were treated for 72 hours with either medium (control, gray) or 5 μg/mL MVs generated from PHA/PMA/act D-treated CEM T cells in the absence (blue trace) or in the presence of either 30 μM cyclopamine (red trace, A-B), 1:150 anti-Smo (red trace, C-D), or 1:150 preimmune sera (green trace, C-D). (E, F) Cells were treated with medium (gray), 1 nM (blue trace), or 3 nM (red trace) SAG (agonist of Smo) for 72 hours. Detection of α_IIbβ₃ and CD42b expression was performed by flow cytometry after labeling by the corresponding antibody. Fluorescence (FL2, red fluorescence channel intensity) is expressed in arbitrary units (au). Data are representative of 8 experiments yielding similar results.