INVASIVE POTENTIALS OF GASTRIC-CARCINOMA CELL-LINES - ROLE OF ALPHA(2) AND ALPHA(6) INTEGRINS IN INVASION

The potentials of the two major histological types of gastric carcinom a to invade through extracellular matrices were studied with cell line s. We found that the invasive potential of intestinal-type carcinoma c ells (MKN-28 and MKN-74) were higher than those of diffuse-type carcin oma cells (MKN-45 and KATO-III). To investigate whether the alpha(2) a nd alpha(6) integrin adhesion molecules are responsible for, or involv ed in carcinoma invasion, we further studied alpha(2) and alpha(6) exp ression patterns in these two types of cell line. Although fluorescenc e-activated cell sorting analysis revealed that all cells examined inv ariably expressed these integrin molecules, their expressional pattern s were different among different cell lines. The intestinal-type carci noma cells expressed integrins mainly along the cell-cell contact regi on, whereas the diffuse-type carcinoma cells showed a diffuse cytoplas mic pattern of integrin expression. Invasion by MKN-28, MKN-74 and MKN -45 cells through reconstituted basement membrane or type I collagen g el was significantly inhibited (P < 0.05) by 50 mu g/ml anti-(alpha(2) integrin) or anti-(alpha(6) integrin) monoclonal antibodies. Our resu lts suggest that active invasiveness is stronger in the intestinal-typ e than in the diffuse-type carcinoma cells and that alpha(2) and alpha (6) integrins play important roles in invasion of both types of gastri c carcinoma cell lines.