Inhibition of lung and liver tumor colonies in mice pretreated with suramin.

The effect of suramin on B16F10 melanoma lung colonies and M5076 reticulosarcoma liver metastasis formation was evaluated in C57B1/6 female mice. Single i.v. doses of 200 mg/kg suramin given 48 and 24 h prior to tumor cell injection significantly inhibited metastasis formation in both models, whereas the same treatment administered 24 h after cell injection was ineffective. A dose-response experiment in the B16F10 melanoma model showed that inhibition of lung colony formation was still significant with 50 mg/kg pretreatment, whereas a borderline effect was observed at 10 mg/kg. At the effective doses, the plasma and organ concentrations of suramin were far below those needed to exert significant in vitro cytotoxic or cytostatic effects on B16F10 and M5076 cells. Thus, in addition to the antineoplastic effect of suramin our results indicate a potential antimetastatic role for this compound.