Anti-epidermal growth factor receptor antibody C225 inhibits angiogenesis in human transitional cell carcinoma growing orthotopically in nude mice

Epidermal growth factor receptor (EGFR) regulates the growth and progressio n of human transitional cell carcinoma (TCC) of the bladder. We have shown that therapy targeting EGFR inhibited the growth of human TCC established o rthotopically in nude mice. The purpose of this study was to evaluate wheth er EGFR-directed therapy affects angiogenesis associated with the growth an d metastasis of human TCC, We determined the cytostatic effect and the effe ct on production of angiogenic factors after in vitro treatment of the huma n TCC cell line 253J B-V with MAb C225, a chimerized monoclonal anti-EGFR a ntibody. The 253J B-V cells were implanted orthotopically into athymic nude mice, and established tumors (4 weeks) were treated with i.p. MAb C225. Ex pression of the angiogenic factors vascular endothelial growth factor (VEGF ), interleukin-8 (IL-8), and basic fibroblast growth factor (bFGF) was eval uated by immunohistochemistry and in situ mRNA hybridization analyses and c orrelated with microvessel density evaluated after immunohistochemical stai ning with anti-CD31, In vitro treatment with MAb C225 inhibited mRNA and pr otein production of VEGF, IL-8, and bFGF by 253J B-V cells in a dose-depend ent manner. MAb C225 therapy of nude mice with established TCCs growing ort hotopically resulted in inhibition of growth and metastasis compared with c ontrols (P < 0.0005). VEGF, IL-8, and bFGF expression was significantly low er in treated tumors than in controls. The down-regulation of these angioge nic factors preceded the involution of blood vessels. These studies indicat e that therapy with anti-EGFR MAb C225 has a significant antitumor effect m ediated, in part, by inhibition of angiogenesis.