Biliary glycoprotein is overexpressed in human colon cancer cells with high metastatic potential

Carcinoembryonic antigen (CEA) has been recently implicated in the process of human colon cancer liver metastasis by means of an adhesion mechanism. Based on the strong sequence and structural homology of biliary glycoprotein (BGP) to CEA, we hypothesized that BGP might be overexpressed at the RNA and protein level in tumor cells with high metastatic potential. We have found the BGP messenger RNA derived from highly metastatic colon cancer cells is constitutively overexpressed-nearly fourfold greater than poorly metastatic cells-and that BGP expression is induced by interferon-gamma. Similarly, we have demonstrated that BGP protein levels were constitutively elevated in highly metastatic human colon cancer cells when compared to poorly metastatic cells. Collectively these results suggest that the basal and interferon-stimulated expression of BGP transcripts may be regulated in a manner similar to CEA and that a potential role in the process of metastasis may be inferred.