Inhibition of NF-KB-rel a expression by antisense oligodeoxynucleotides suppresses synthesis of urokinase-type plasminogen activator (uPA) but not its inhibitor PAL-1

The essential role of uroklnase-type plasminogen activator (uPA) in tumor invasion and metastasis stresses the necessity of a fine-tuned cellular control over its expression. It has been shown that changes in uPA directly correlate with changes in cell invasive ness. We examined the role of Rel-related proteins in uPA synthesis by human ovarian cancer cells by inhibiting their expression using the antisense (AS) oligodeoxynucleotide (ODN) technology. Exposure of OV-MZ-6 cells to 10μM phosphorothioate (PS)-dervatized AS-ODN directed to Rel A led to a maximal 50% decrease of uPA antigen in cell lysates and a 70% reduction in cell culture supematants accompanied by a significant transient decline in uPA mRNA levels. Antisense-PS-ODN directed to NF-kB1 (p50) or c-rel had no effect on uPA protein expression. AS-PS-ODN directed to Rel A also affected the proteotytic capacity of OV-MZ-6 cells reflected by an -70% decrease in the tibrinolytic capacity of the cells within 24 h compared to untreated controls. AS-PS-ODN directed to 1kBα expression increased uPA in cell culture supematants up to 50%. uPA receptor (uPAR) production and synthesis of plasminogen activator inhibitor type-1 (PM-1) were not altered by either AS-PS-ODN applied. Western blot and gel retardation analyses revealed constitutive expression of Relrelated proteins in nuclear protein extracts of OV-MZ-6 cells. Thus these proteins seem to be implicated in uPA regulation and may thereby contribute to tumor spread and metastasis.