Abstract
A Kunitz‐type protease inhibitor, bikunin, is known to suppress the invasion and metastasis of cancer cells. HI8, a carboxyl‐terminal domain of bikunin, is an active site of this glycoprotein. To increase its affinity for cancer cells, we constructed a chimeric gene, ATF‐HI8, and investigated the anti‐invasive and anti‐migratory activity of ATF‐HI8 on ovarian cancer cells. ATF‐HI8‐expressing plasmid and ATF‐expressing plasmid were introduced into the highly invasive and metastatic ovarian cancer cell line HRA. The properties of the established cell line (HRA/ATF‐HI8) were compared to those of the HRA/ATF and the HRA/luciferase (HRA/LUC, control) cell lines in terms of cell proliferation, invasion and migration. As a result, (i) there were no differences in cell proliferation between HRA/ATF‐HI8 and HRA/LUC; (ii) the invasion and migration of HRA/ATF‐HI8 cells were significantly inhibited compared to those of HRA/LUC cells; (iii) the migration, but not the invasion, of HRA/ATF cells was significantly inhibited compared to that of HRA/LUC. These results indicate that the overexpression of ATF‐HI8 inhibits the invasion and migration of ovarian cancer cells without affecting cell proliferation and suggest that HI8 is involved in the anti‐invasive and the anti‐migratory activities, and the addition of ATF brought about the increase in the anti‐migratory activity of HI8. The above findings suggest the applicability of therapeutic strategies targeting the inhibition of peritoneal invasion and dissemination of ovarian cancer by the use of the chimeric gene ATF‐HI8.