Laminin receptor expression on murine tumor cells: correlation with sensitivity to natural cell-mediated cytotoxicity.

Previous studies have identified a relationship between the presence of cell surface laminin receptors on murine tumor cells and sensitivity to killing by natural killer (NK) cells. On the basis of these observations, we suggested that laminin and laminin receptors may function to facilitate the interaction of NK-sensitive murine target cells with NK cells. Our original studies were conducted with a number of genetically unrelated tumor cell lines. In order to extend these earlier observations, studies have now been conducted in which sensitivity to NK-mediated lysis and responsiveness to laminin were compared in a number of variant populations derived from the NK-sensitive cell lines Yac-1 and RL-1 and from the NK/NC-resistant line P815. All of the lines which interacted with murine NK cells as indicated by sensitivity to killing and/or by ability to "cold-target" compete with the killing of sensitive Yac-1 cells were able to bind 125I-laminin and to respond to laminin in an aggregation assay. Of 4 NK-resistant populations identified in these studies, 3 failed to respond to laminin. These studies indicate that even among genetically related tumor cell lines there is a relationship between laminin receptor expression and interaction with NK cells.