Surface membrane glycoproteins of cultured human pancreatic cancer cells

The cell-surface glycoproteins and proteins of four human pancreatic cell lines (MIA PaCa-2, PANC-1, HS766T, and CAPAN-1) were separately tritiated using galactose oxidase/NaB(3H)4 and iodinated using lactoperoxidase/125I. Gel electrophoresis showed that the cell lines had very different surface components. All four cell lines were tested for cell-surface antigens that cross-reacted with antisera raised against carcinoembryonic antigen and against the membrane fractions of MIA Pa Ca-2 and CAPAN-1 cells. CAPAN-1 cells reacted most strongly with all three antisera. Seventeen cell-surface proteins can be detected when CAPAN-1 cells are labeled using lactoperoxidase. The labeled membranes were solubilized in detergent and subjected to affinity chromatography on Sepharose-conjugated lectins. The bound proteins were eluted and analyzed on gel electrophoresis . All 17 proteins capable of being labeled by lactoperoxidase bound to at least one lectin column, indicating they are all glycoproteins.