Changes in cell-cycle distribution of K562 cells induced by modulation of the Hh pathway. Cells growing asynchronously were preincubated for 30 minutes in the presence of medium (control), 30 μM cyclopamine (cycl), anti-Smo (@Smo; 1:150) or preimmune (@control; 1:150) sera, and treated with MVs generated from PHA/PMA/act D-treated CEM T cells (Hh⁺ MVs) for 72 hours, and were then stained with propidium iodide. Cell cycle was analyzed by flow cytometry. (A) Histograms represent the content of R2 gates corresponding to subpopulation with less than 4N DNA content as shown in inset dot plots. Dot plots were displayed as FL2-A versus FL2-W to show nuclei doublets. R1 and R2 gates correspond to populations with more than 4N and less than 4N DNA content, respectively. Fluorescence (FL2, red fluorescence channel intensity) is expressed in arbitrary units (au). Seven experiments yielding similar results were performed. (B) Histograms representing the mean (± SEM) of number of events reflecting each cycle phase of cells preincubated for 30 minutes in the presence of medium (control), 30 μM cyclopamine (cycl), anti-Smo (@Smo; 1:150) or preimmune (@control; 1:150) sera and treated with MVs generated from PHA/PMA/act D-treated CEM T cells (Hh⁺ MVs) for 72 hours. *P < .05, **P < .01, significantly different from nontreated control cells; †P < .05, significantly different from 5-μg/mL MV-treated cells.