Fig. 3. Requirement of uPAR for HOXA3-dependent invasion of endothelial cells. (a) Control-transfected HMEC after 48 hours in fibrin gels (original magnification x100). Extensive invasion of fibrin gels is observed after 48 hours in HMEC-1 stably expressing HOXA3 (b). (c) Invasion of HOXA3-expressing HMEC-1, 48 hours after addition of function-blocking antibodies against uPAR. (d) Migration was quantified by measuring the distance from the edge of the cytodex bead to the most distal point of migration in the gel, control (open bar), +HOXA3 (black bar), or +HOXA3 plus 25 µg of a function blocking antibody against uPAR (hatched bar). Results are the mean±s.d. of four experiments. **P<0.05 when compared with migration of control cells.