Suramin inhibits growth of human osteosarcoma xenografts in nude mice

The effect of suramin on tumor growth and morphology in two different human osteosarcoma xenografts (L-I OSM and L-II OSM) grown in BALB/cA-nu/nu mice was studied. Suramin (total dose, 720 mg/kg) given by i.p. injection (60 mg/kg/dose) for up to 9 weeks significantly inhibited osteosarcoma cell growth in both tumors, suramin-treated tumors showing only one-third or less of the volume of nontreated controls. Cell cycle distribution of tumor cells measured by DNA flow cytometry demonstrated that suramin treated caused accumulation of cells in the S and G2 phases of the cell cycle, in both L-I OSM and L-II OSM. In the aneuploid L-II OSM tumor suramin preferentially inhibited the growth of aneuploid cells, leading to a decrease in the ratio of aneuploid to diploid cells. Both osteosarcomas retained their histological appearance and the liver, spleen, heart, and kidneys of the treated animals were unaffected by suramin. These results are compatible with the view that suramin inhibits the growth of human osteosarcomas by cytostatic effects.