Galectin-1 Induces Cell Adhesion to the Extracellular Matrix and Apoptosis of Non-Adherent Human Colon Cancer Colo 201 Cells

抄録

To isolate cDNAs for molecules involved in cell adhesion to the extracellular matrix, expression cloning with non-adherent colon cancer Colo 201 cells was carried out. Four positive clones were isolated and, when sequenced, one was found to be galectin-1, a β-galactoside-binding protein. When cultured on fibronectin-, laminin-, and collagen-coated and non-coated dishes, the adherent galectin-1 cDNA-transfected Colo 201 cells increased and spread somewhat. Immunofluorescence staining revealed that galectin-1 was expressed inside and outside of Colo 201 cells. The adhesion was dependent on the carbohydrate-recognition domain of galectin-1 since lactose inhibited the adhesion and exogenously-added galectin-1 caused the adhesion. PD 58059, an inhibitor of mitogen-activated protein kinase, or LY 294002, a phosphoinositide 3-OH kinase inhibitor, decreased the adhesion. Furthermore, the expression of galectin-1 in Colo 201 cells induced apoptotic cell death, while exogenously-added galectin-1 did not cause apoptosis. These results indicate that galectin-1 plays a role in both cell-matrix interactions and the inhibition of Colo 201 cell proliferation, and suggest that galectin-1 expressed in cells could be associated with apoptosis.