VEGF Trapon inhibits tumor growth in papillary thyroid carcinoma.

OBJECTIVE: Vascular endothe - lial growth factor (VEGF) is the most potent in - ducer of neovasculature, and its increased ex - pression has been related to a worse clinical outcome in many disease. Angiogenesis from thyroid cancer cell plays the important roles in post-surgical persistent, recurrent, and metastatic papillary thyroid cancer (PTC). Vas - cular endothelial growth factor (VEGF) Trapon is a newly developedVEGF-blocking agent with stronger affinity and broader activity than the anti-VEGF antibody bevacizumab. In this study, we tested the activity ofVEGFTrapon on a PTC model in vivo. MATERIALS AND METHODS: BC-PAP (de - rived from papillary carcinomas) transfected with a luciferase-expressing vector were inject - ed into the back to mice. I.p. treatment with VEGFTrapon or control protein (25 mg/kg twice weekly) was started shortly after tumor injec - tion to prevent tumor development (prevention model) or after established tumors were formed to inhibit tumor growth and metastasis forma - tion (intervention model). RESULTS: In the prevention model, VEGF Trapon inhibited tumor growth by 73 ± 12% compared with control ( p = 0.014) and signifi - cantly prolonged survival. In the intervention model, VEGF Trapon inhibited tumor growth by 68 ± 7% ( p < 0.01). Microvascular density was reduced by 56% due to VEGF Trapon treatment (p < 0.01). CONCLUSIONS: VEGF Trapon is a potent in - hibitor of BC-PAP tumor growth, angiogenesis and blocks the biological function of VEGF in vivo. These results support further clinical de - velopment of VEGF Trapon for PTC and other cancer types.