Increased adhesion potency of ovarian carcinoma cells to mesothelial cells by overexpression of dipeptidyl peptidase IV

Dipeptidyl peptidase IV (DPPIV), cell surface peptidase, works as an adhesion molecule as well as an enzyme. To investigate the role of DPPIV as an adhesion molecule of ovarian carcinoma cells to mesothelial cells, ovarian carcinoma (SKOV3 and NOS4) cells were transfected with a sense and an antisense cDNA coding human DPPIV. The adhesion potency of these transfected cells to fibronectin and collagen-coated plates and mesothelial cells were examined with or without fibronectin. Flow cytometry and immunohisto-chemistry demonstrated DPPIV in ovarian carcinoma cells. The adhesion rate of DPPIV-transfected SKOV3 (SKDPIV) cells to fibronectin-coated plates was significantly higher than SKOV3 cells, while there was no difference in the adhesion rate to non-coated plates between SKDPIV and SKOV3 cells. The adhesion rates of Vector-transfected SKOV3 (SKpcDNA) cells to coating and noncoating plates were similar to those of SKOV3 cells. SKDPIV cells showed twofold adhesion potency to mesothelial cells compared to SKOV3 cells. Furthermore, an addition of soluble fibronectin resulted in a dose-dependent increase in the adhesion rate of SKDPPIV cells, but not in either SKOV3 or SKpcDNA cells. Antisense-transfected NOS4 cells decreased the adhesion potency compared to NOS4 and vector-transfected NOS4 cells. In conclusion, ovarian carcinoma cells express DPPIV and adhere to human mesothelial cells in part by DPPIV. This adhesion mechanism of DPPIV is mediated by immobilized and soluble fibronectin.