MUTATIONAL ANALYSIS OF THE GENES ENCODING UROKINASE-TYPE PLASMINOGEN-ACTIVATOR (UPA) AND ITS INHIBITOR PAI-1 IN ADVANCED OVARIAN-CANCER

Evidence has accumulated that urokinase-type plasminogen activator (uP A), its inhibitor (PAI-1) and: receptor (uPAR) are involved in tumor i nvasion and metastasis. We analyzed the DNA sequences encoding these f actors to see if they are altered in the ovarian cancer cell lines OV- MZ-6, OV-MZ-19 and OVCAR-3. In the uPA-encoding cDNA derived from OV-M Z-6 cells (but not in the uPA-cDNA from OVCAR-3 and OV-MZ-19), a so-fa r unknown mutation was identified in codon 121, resulting in a proline to leucine exchange. This exchange creates an AluI restriction site m aking restriction fragment length polymorphism (RFLP) analyses possibl e. Previously published PAI-1 sequences pointed to a variation of amin o acid 15 of the PAI-1 signal sequence representing either threonine o r alanine, which was confirmed in the present study. The uPAR cDNAs of all three cell lines encoded the published wild-type sequence. In ord er to elucidate the possible role of the Pro121Leu exchange in uPA and the Ala/Thr variants in the signal sequence of PAI-1 in the developme nt and/or progression of human ovarian cancer, we studied the presence of these mutants or variants in a series of 22 ovarian cancer tissues . In addition to the wild-type sequence, the Pro121Leu exchange in the uPA sequence was detected in 10 out of 22 tumor tissues; 11 tumors ca rried exclusively the Pro121 allele; in one case exclusively the Leu12 1 allele was detected. In 18/22 tumors, triplet 15 in the signal seque nce of PAI-1 encoded alanine, four DNAs contained both the Ala and the Thr allele. Furthermore, we analyzed another known common single-base -pair insertion/deletion polymorphism (ins/del allele) found in the pr omoter region of the PAI-1 gene and thought to be of functional import ance in regulating PAI-1 gene expression. The PAI-1 ins-allele was fou nd in 3/22, the del-allele in 6/22 and both alleles in 13/22 ovarian c ancer tissues. In genomic DNA isolated from peripheral blood of 23 hea lthy donors, we observed similar allele frequencies of the three polym orphisms as found in the 22 ovarian carcinomas. Taken together, these results suggest that the polymorphisms observed in the uPA and PAI-1 g enes may not be linked to ovarian cancer.