Antibody to type I insulinlike growth factor receptor inhibits growth of Wilms' tumor in culture and in athymic mice.

The role of the type I insulinlike growth factor (IGF) receptor in regulating growth of Wilms' tumor (WT) was evaluated by examining the effect of antibody-mediated inhibition of this receptor on tumor growth in cell cultures and as heterotransplants in athymic mice. An antibody to the human type I IGF receptor (alpha IR-3) inhibited 125I-IGF-1 binding and prevented stimulation of thymidine incorporation by IGF-1 in vitro. Intraperitoneal administration of alpha IR-3 to nude mice bearing WT heterotransplants prevented tumor growth for 4 weeks and resulted in partial regression of established tumors. These data indicate the importance of IGF action in control of WT growth in vivo, and suggest potential therapeutic application using antigrowth factor receptor antibodies to block growth factor action.