Fig. 3. siRNA-mediated knockdown of PKC in MDCK cells suppresses their migration. (A) Doxycycline-inducible expression of the PKC siRNA was established in MDCK cells. Parental MDCK cells, a control siRNA clone and two PKC-specific siRNA clones were grown in the medium supplemented with (+) or without (-) 2 µg/ml doxycycline for 72 hours before lysis. The expression and activity of PKC was analyzed. The expression levels of PKC, PKC and tubulin were analyzed and served as the control. (B) Cells were grown in medium with (+) or without (-) 2 µg/ml doxycycline for 72 hours and then subjected to a Trans-well cell migration assay. Values (means ± s.d.) are from three independent experiments, relative to the level of the control MDCK cells, which was defined as 100%. ^*P<0.05 compared with their counterparts in the medium without doxycycline.