Ezrin primarily acts as a linker between the plasma membrane and the cytoskeleton and is a key component in
tumor metastasis. In the present study, RNA interference (RNAi) using
ezrin small hairpin RNAs (
ezrin shRNAs) was used to define the roles of
ezrin in the regulation of malignant behaviors of human
breast cancer. The highly metastatic human
breast cancer cell MDA-MB-231, in which
ezrin mRNA and
protein levels are the highest, was selected as a cell model in vitro. In addition, we also found that
ezrin expression was up-regulated and its immuno-staining trans-located from cell membrane to cytoplasm, whereas
E-cadherin expression decreased and showed the same cell distribution as
ezrin in
lymphatic metastases of human
breast carcinomas. After repression of
ezrin by more than 85% of G3PDH and 75% of
beta-actin in
mRNA and
protein levels was maintained in the stable expressing
ezrin shRNAs MDA-MB-231 cell clones, the abilities of cell motility and invasiveness were obviously inhibited with a 4-fold and 2-fold, respectively, and the altered cell polarity was observed. Western blot analyses further revealed that the silencing of
ezrin induced an increased
E-cadherin expression and a decreased phosphorylation of
beta-catenin by inhibiting phosphorylation levels of c-src. These data indicate that
ezrin overexpression positively correlated with metastatic potentials of human
breast cancer cells, especially lymphatic system
metastasis. Decreased
ezrin expression by
shRNA reversed metastatic behaviors of human
breast cancer cells by inducing c-src-mediated
E-cadherin expression, suggesting that
ezrin may have potential values in assessing
lymphatic metastasis of human breast
cancers.