Silencing of partitioning-defective protein 6 (Par6) inhibits transforming growth factor-β1 (TGF-β1)-induced epithelial-mesenchymal transition (EMT). (A) Small interfering RNA (siRNA) was transfected into NRK-52E cells for 24 and 48 h to suppress the expression of Par6 and p-Par6, which was measured by western blot analysis. C, si-RNA-control; S, siRNA-Par6. The NRK-52E cells were untreated (control), or incubated with TGF-β1 (20 ng/ml) for 71 h, or incubated with TGF-β1 (20 ng/ml) combined with Par6-siRNA for 72 h. (B) The protein expression levels of E-cadherin, α-SMA and Cdc42-interacting protein-4 (CIP4) were measured by western blot analysis and densitometric analyses. E-cadherin and α-SMA were visualized by confocal fluorescence microscopy. (C) Cell nuclei were enhanced by staining of the cell nuclei with DAPI for E-cadherin (×600 magnification). Values are expressed as the means ± SEM, n=3 in each group. *P<0.05 vs. control group; #P<0.05 vs. TGF-β1-stimulted group.