Interaction between cyclooxygenase-2, Snail, and E-cadherin in gastric cancer cells

Figure 1 Effect of cyclooxygenase-2 knockdown on the expression of nuclear factor-κB, Snail, and E-cadherin in gastric cancer cells. Among the four human gastric cancer cell lines, SGC-7901 has the highest expression level of cyclooxygenase-2 (COX-2) at mRNA (A) and protein level (B). Thus, this cell line was used to study the regulatory effect of COX-2 on nuclear factor-κB (NF-κB), Snail, and E-cadherin. Successful knockdown of COX-2 was confirmed at mRNA (C) and protein (D) levels. Down-regulation of COX-2 led to a reduction of NF-κB subunit p65 and Snail but an increased E-Cadherin, both at the mRNA (E) and protein (F) levels. mRNA expression was examined by quantitative polymerase chain reaction (qPCR) and expressed as a relative arbitrary unit against that of β-actin. Protein expression was examined by Western blot (^aP < 0.05 vs their respective controls).