Autocrine regulation of growth stimulation in human epithelial ovarian carcinoma by serine-proteinase-catalysed release of the urinary-type-plasminogen-activator N-terminal fragment

Abstract

Ovarian carcinomas secrete single-chain urinary-type plasminogen activator (scuPA) and expression of uPA is up-regulated relative to normal ovarian epithelium, leading to an enhanced proteolytic capacity which may facilitate invasion. Furthermore, the uPA receptor (uPAR) is present on ovarian carcinoma cells and is occupied in tumour tissues. In the present study, incubation of scuPA with serum-free conditioned medium from ovarian carcinoma cells resulted in release of a 14 kDa polypeptide. N-terminal sequence analysis identified this fragment as the uPA N-terminal fragment (NTF), which contains a growth-factor and a kringle domain. NTF generation was abolished by serine-proteinase inhibitors, but not inhibitors of matrix metalloproteinases, and was not enhanced by the addition of plasminogen or plasmin. To determine whether ovarian carcinoma-cell growth is altered by uPA, the effect of exogenous scuPA or NTF on proliferation was analysed. Both NTF and scuPA induced a dose-dependent increase in proliferation, with maximal stimulation obtained at 10-20 nM. Furthermore, blocking the interaction of endogenous uPA with uPAR using anti-NTF antibodies significantly inhibited proliferation. Together these data indicate that, in addition to enhancing the invasive activity of ovarian carcinoma cells via increased pericellular proteolysis, uPA also acts as a mitogen for ovarian carcinoma cells, suggesting a biochemical mechanism whereby uPA may contribute to ovarian carcinoma progression by modulating both cell invasion and proliferation.

Serum-stable RNA aptamers to urokinase-type plasminogen activator blocking receptor binding

“…In cell culture experiments such antibodies inhibit (1) uPA-induced migration of MCF-7 cells (Nguyen et al 1999), (2) the mitogenic effect caused by adding exogenous uPA or ATF to ovarian carcinoma cells (Fishman et al 1999) or exogenous epidermal growth factor (EGF) to MDA-MB-231 cells (Jo et al 2007), (3) as well as the effects of endogenously produced uPA on cell growth and rescue of MDA-MB-231 cells from apoptosis (Ma et al 2001). The role of the uPA-uPAR interaction in uPA aptamers blocking uPA receptor binding www.rnajournal.org 2365 prevention of apoptosis for some cancer cells suggests that uPA-directed uPA-uPAR inhibitors may in some cases lead to tumor regression, an important property of a potential anticancer compound.…”

Βιολογικοί Δείκτες Στον Καρκίνο Των Ωοθηκών. Παρακολούθηση Στο Αίμα Και Στο Ασκιτικό Υγρό Των Ασθενών

“…Στην προσιτή σε μας βιβλιογραφία δε βρέθηκε μελέτη που να αφορά την ανοσοϊστοχημική έκφραση αυτού του συστήματος, σε τομές παραφίνης από όγκους των ωοθηκών, την εντόπισή του επακριβώς στο κύτταρο και τη συσχέτισή του 127,128,129,130,131,132,133,134,135,136,137,138 .…”