Abstract
We investigated the biological role of the expression of ICAM-1, which is an adhesion molecule involved in host immunodefense in the microenvironment, and of TGF-β1in the liver metastasis ability of pancreatic cancer cells. The highly metastatic, SW1990cells in a nude mouse liver metastasis model had the lowest expression of ICAM-1, and the adhesiveness and cytotoxicity of mononuclear leukocytes against SW1990were suppressed. Treatment of pancreatic cancer cells with TGF-β1decreased their expression of ICAM-1and increased their invasiveness, and it enhanced the in vivo liver metastasis ability of SW1990and CAPAN-2. These findings suggested that decreased cancer cell expression of ICAM-1induced by various factors, such an TGF-β1, plays an important role by allowing cancer cells to escape from the immune defense system, and ICAM-1gene transfection or anti-TGF-β1antibody may be applicable as a means of inhibiting metastasis.
