Inhibition of insulin like growth factor II autocrine growth of Wilmsʹ tumor by suramin in vitro and in vivo

Suramin was found to affect the Wilmsʹ tumor (WT) cell line, W13, by inhibiting in vitro growth (half-maximal inhibitory dose (ID50) = 11 μM), insulin like growth factor II (IGF-II) cell binding (ID50 = 10μM) and IGF-II induced DNA synthesis (ID50 = 8μM). In addition, suramin inhibited cross-linking of [125I]IGF-II to the type 1 IGF receptor (IGF1R) and type 2 IGF receptor (IGF2R). Disruption of IGF-II/IGF1R interaction appears to be the main mode of action of suramin since the suramin response was abolished in the presence of the IGF1R blocking antibody, αIR-3. When administered to athymic mice bearing W13 heterotransplants, suramin suppressed the linear tumor growth rate by 64%.