Alterations in the expression of EMT markers in FAK siRNA-treated cells. (A) RT-qPCR analysis of the mRNA expression levels of FAK, Snail, Slug and Twist1 in the FAK siRNA group and negative control siRNA group. (B) RT-qPCR analysis of the mRNA expression levels of E-cadherin, cytokeratin, N-cadherin and vimentin in the FAK siRNA group and negative control group. (C) Western blot analysis of protein expression levels of E-cadherin and vimentin in the FAK siRNA and negative control groups. (D) Relative protein expression levels of E-cadherin and vimentin in the FAK siRNA and negative control groups. The mRNA and protein expression levels were normalized to GAPDH. *P<0.05 and **P<0.01 vs. negative control. FAK, focal adhesion kinase; RT-qPCR, reverse transcription-quantitative polymerase chain reaction; siRNA, small interfering RNA; Twist1, Twist-related protein 1.