Highly specific antiangiogenic therapy is effective in suppressing growth of experimental Wilms tumors.

ABSTRACT

BACKGROUND/PURPOSE: Pathologic angiogenesis in tumors is a potential target for novel therapies. Vascular endothelial growth factor (VEGF) is an angiogenic promoter present in a wide variety of human tumors. VEGF is expressed as 4 isoforms; one of these, VEGF165, predominates in human tumors. The authors hypothesized that antagonism of VEGF165 by a specific aptamer would block tumor growth in an experimental model of Wilms tumor. METHODS: VEGF isoform expression in clinical (n = 2) and experimental tumors were evaluated by reverse transcription polymerase chain reaction (RT-PCR). Tumors were induced in NCR nude mice (n = 32) by intrarenal injection of 10(6) cultured Wilms tumor cells. At 1 week, aptamer (n = 16) or vehicle (n = 16) treatment was started and continued daily for 5 weeks. RESULTS: At 6 weeks tumors weighed 84% less in treated versus control animals (0.69 v 4.41 g; P <.028), without observed adverse effects and similar to suppression previously reported using nonisoform-specific anti-VEGF antibody (94% to 96%). CONCLUSIONS: Anti-VEGF165 aptamer effectively suppressed primary tumor growth in experimental animals with no observed adverse effects. Development of highly specific antiangiogenic therapies may be of particular benefit to pediatric patients.