The epithelial-to-mesenchymal transition (EMT), a process involving the breakdown of cell-cell junctions and loss of epithelial polarity, is closely related to
cancer metastasis and invasion. The
epithelial cell adhesion molecule (
EpCAM) is a type I transmembrane
protein expressed in the majority of normal epithelial tissues and overexpressed in the majority of human epithelial
cancers including
breast cancer.
EpCAM plays an important role in
cancer progression. We showed that
EpCAM participated in TGF-β1-induced EMT. TGF-β1 treatment of MCF-7
breast cancer cells was shown to induce
EpCAM expression, which promoted the EMT and cell migration.
EpCAM overexpression further enhanced TGF-β1-induced EMT and
EpCAM knockdown inhibited TGF-β1-induced EMT. We further demonstrated that TGF-β1 treatment induced the phosphorylation of JNK that was in turn responsible for the increased expression of Jun and Fos. This result suggests an important role of the JNK to
AP-1 signaling to
EpCAM downstream of TGF-β1 for the induction of EMT in the
breast cancer cells. Collectively, our study highlights a novel function for
EpCAM in TGF-β1-induced EMT process and suggests that targeting of
EpCAM may be an attractive strategy to treat
breast cancer. This study implicates the potential value of
EpCAM as a molecular marker for
breast cancer.