INHIBITION OF NF-KAPPA-B-REL-A EXPRESSION BY ANTISENSE OLIGODEOXYNUCLEOTIDES SUPPRESSES SYNTHESIS OF UROKINASE-TYPE PLASMINOGEN-ACTIVATOR (UPA) BUT NOT ITS INHIBITOR PAI-1

The essential role of urokinase-type plasminogen activator (uPA) in tu mor invasion and metastasis stresses the necessity of a fine-tuned cel lular control over its expression. It has been shown that changes in u PA directly correlate with changes in cell invasiveness. We examined t he role of Rel-related proteins in uPA synthesis by human ovarian canc er cells by inhibiting their expression using the antisense (AS) oligo deoxynucleotide (ODN) technology. Exposure of OV-MZ-6 cells to in mu M phosphorothioate (PS)-derivatized AS-ODN directed to Rel A led to a m aximal 50% decrease of uPA antigen in cell lysates and a 70% reduction in cell culture supernatants accompanied by a significant transient d ecline in uPA mRNA levels. Antisense-PS-ODN directed to NF-kappa B1 (p 50) or c-rel had no effect on uPA protein expression. AS-PS-ODN direct ed to Rel A also affected the proteolytic capacity of OV-MZ-6 cells re flected by an similar to 70% decrease in the fibrinolytic capacity of the cells within 24 h compared to untreated controls. AS-PS-ODN direct ed to I kappa B alpha expression increased uPA in cell culture superna tants up to 50%. uPA receptor (uPAR) production and synthesis of plasm inogen activator inhibitor type-1 (PAl-1) were not altered by either A S-PS-ODN applied. Western blot and gel retardation analyses revealed c onstitutive expression of Rel-related proteins in nuclear protein extr acts of OV-MZ-6 cells. Thus these proteins seem to be implicated in uP A regulation and may thereby contribute to tumor spread and metastasis .