cDNA transfection of amino-terminal fragment of urokinase efficiently inhibits cancer cell invasion and metastasis

Focusing of urokinase-type plasminogen activator (uPA) to the cell surface via binding to its specific receptor (uPAR, CD87) is critical for tumor inv asion and metastasis. Consequently, the inhibition of uPA-uPAR interaction on the cell surface might be a promising anti-invasion and anti-metastasis strategy. We examined the effects of cDNA transfection of the human uPA ami no-terminal fragment (ATF) on invasion and metastasis of cancer cells. Firs t, a highly metastatic human lung giant-cell carcinoma cell line (PG), used as the target cell for evaluation of this effect, was demonstrated to expr ess both uPA and uPAR, Then, ATF, which contains an intact uPAR binding sit e but is catalytically inactive, was designed as an antagonist of uPA-uPAR interaction and was transfected into PG cells. [H-3]-Thymidine incorporatio n and cell growth curves indicated that expressed ATF did not affect the pr oliferation of transfected cells. However, analysis by scanning electron mi croscopy revealed that ATF changed the host cells from the typical invasive phenotype to a noninvasive one. Correspondingly, the modified Boyden chamb er test in vitro showed that ATF expression significantly decreased the inv asive capacity of transfected cells, Furthermore, in the spontaneous metast asis model, it was confirmed in vivo that expressed ATF remarkably inhibite d lung metastasis of implanted ATF-transfected PG cells. In summary, autocr ine ATF could act as an antagonist of uPA-uPAR interaction, and ATF cDNA tr ansfection could efficiently inhibit the invasion and metastasis of the can cer cells, Inhibition of uPA-uPAR interaction on the cell surface might be a promising anti-invasion and anti-metastasis strategy.