Abstract

Suramin, a new type of cancer chemotherapeutic agent with growth factor antagonist properties, has been reported to affect growth of prostate cancer metastatic lesions. Partin et al. have previously reported that prostate cancer cell motility was essential for tumor cell metastasis. We have studied the effects of suramin on cell motility and cell growth in a prostate cancer cell model. We have demonstrated that suramin has differential effects on rat prostate cancer cells in vitro. The effects of suramin on cell growth were biphasic. At low concentrations of 0.01 mM and 0.1 mM, suramin stimulated growth while it was inhibitory at a higher concentration of 1.0 mM, and 10 mM suramin resulted in cell death. Cell motility was inhibited at a suramin concentration above 0.1 mM. The inhibition of cell motility by suramin may be through the blockage of growth factor effects. Reducing serum growth factor concentration reduced cell motility and the motility was restored by the addition of basic fibroblast growth factor (bFGF) to the media. Motility which had been restored by bFGF could then be blocked by the presence of suramin. The inhibition of cell motility by suramin is reversible on washout of the drug. Suramin inhibits cell motility in both the human prostate cancer cells (LNCaP) and the rat (MLL).