A Monoclonal Antibody to Human Angiogenin Suppresses Tumor Growth in Athymie Mice1

Human angiogenin, a potent inducer of neovascularization, is secreted by HT-29 colon adenocarcinoma cells, ug doses of a monoclonal antibody that neutralizes the in vitro and in vivo activities of angiogenin prevent or delay the appearance of s.c. HT-29 tumors in athymic mice in a statisti cally significant, dose-dependent manner. The antibody is not cytotoxic to tumor cells in vitro, which indicates that inhibition of tumor growth most likely occurs by neutralization of the activity of angiogenin in vivo and further implies a critical role for angiogenin in the early development of HT-29 tumors. The results suggest a therapeutical!}' useful approach to the treatment of angiogenin-dependent malignancy.