Role of urokinase and its receptor in basal and stimulated colonic epithelial cell migration in vitro

Background-Migration of colonic epithelial cells is important for mucosal r epair following injury. The urokinase (u-PA) system regulates migration in other cell types. Aim-To examine the role of u-PA and its receptor (u-PAR) in colonic epithel ial cell migration. Methods-Migration was assessed over 24 hours in circula r wounds made in confluent monolayers of LIM1215 and Caco-2 human colon can cer cells. The function of u-PA and u-PAR was ablated with antisense oligon ucleotides to block expression, with synthetic u-PA peptides to block inter action, and with aprotinin to block u-PA mediated proteolysis. Results-Migration was stimulated two to threefold by exogenous u-PA, an eff ect dependent on u-PAR binding but independent of u-FA mediated mitogenesis and proteolysis. Expression of u-PA and u-PAR was inhibited by 80% by the appropriate antisense oligonucleotide. Basal migration and the motogenic ef fects of butyrate, epidermal growth factor, and phorbol-12-myristate-13-ace tate were suppressed by the u-PAR antisense oligonucleotide (40-60%) but we re at best minimally affected following inhibition of u-PA expression and b inding. Conclusions-In an in vitro model of wounded colonic epithelium, u-PAR promo tes cell migration through mechanisms that are not exclusively dependent on u-PA binding. Therefore, u-PA and u-PAR may contribute to colonic mucosal repair in vivo.