EPLIN, epithelial protein lost in neoplasm.

We have identified a novel cytoskeletal protein, EPLIN (Epithelial Protein Lost In Neoplasm), that is preferentially expressed in human epithelial cells. Two EPLIN isoforms, a 600 amino acid EPLIN-alpha and a 759 amino acid EPLIN-beta, are detected in primary epithelial cells of oral mucosa, prostate and mammary glands. The expression of EPLIN-alpha is either down-regulated or lost in the majority of oral cancer cell lines (8/8), prostate cancer cell lines (4/4) and xenograft tumors (3/3), and breast cancer cell lines (5/6). The amino acid sequence of EPLIN is characterized by the presence of a single centrally located LIM domain. Both EPLIN isoforms localize to filamentous actin and suppress cell proliferation when overexpressed. These findings indicate that the loss of EPLIN seen in cancer cells may play a role in cancer progression.