Figure 5.

rAAV-endostatin suppresses RCC tumor growth through the inhibition of angiogenesis. (A) Inhibition of chemotactic activity of human umbilical vein endothelial cells treated with OS-RC-2-endostatin culture supernatant in vitro; *P<0.05 vs. rAVV-EYFP. (B) Following injection of rAAV-endostatin (1×10¹¹ v.p), the serum concentration of endostatin rose continuously, peaked at day 60, and was maintained at a sustained level of 30–40 ng/ml thereafter, indicating that single use of rAAV-endostatin may lead to durative endostatin expression and secretion, and this concentration of endostatin may inhibit tumor angiogenesis effectively. (C) Following immunohistochemistry staining, the microvessel density of xenograft tumors of the group injected with rAAV-Endostatin was 8.30±3.14/0.739 mm² whereas those of the control groups were 13.87±4.09/0.739 mm² (rAVV-EYFP) and 13.76±3.50/0.739 mm² (RPMI-1640) (n=8). The result suggests that single injection of rAAV-endostatin may inhibit tumor angiogenesis. *P<0.05 vs. rAVV-EYFP or RPMI1640. rAAV, recombinant adenovirus-associated vector; EYFP, enhanced yellow florescent protein.