Effects of MIIA or MIIB depletion on the migration of CHO-α4WT cells in microchannels. (A) CHO-α4WT cells were either transfected with an siRNA for MIIA (a) or MIIB (b), a control (Ctrl) siRNA, with lipofectamine only (LF), or remained untransfected (non). The depletion of either MIIA or MIIB by their corresponding siRNAs was demonstrated by immunoblotting using an anti-MIIA or anti-MIIB antibody. β-Actin served as an internal control. (B) The migration velocities of MIIA- or MIIB-depleted CHO-α4WT cells and siRNA controls were quantified as a function of channel width. (C) The migration velocity of CHO-α4WT cells, treated with either ML-7 or a vehicle control, was measured in channels of different widths. In B and C, all channels were coated with VCAM-1. Data represent means ± SEM of >45 cells from three independent experiments. *, P < 0.005. The images of cells migrating inside 50- or 6-µm microchannels at designated time points are also shown. White arrowheads show the centroid of the cell body.