Suramin inhibits growth factor binding and proliferation by urothelial carcinoma cell cultures

Suramin is a polyanionic compound recently noted to inhibit growth factor action and proliferation of several types of neoplastic cells in vitro. Data from clinical trials show antineoplastic activity against some prostatic and adrenal cortical carcinomas. Suramin is excreted unmetabolized into the urine suggesting possible application in treatment of urothelial carcinoma and prompting us to examine the drug's effect on growth factor binding and cell proliferation by two urothelial carcinoma cell lines. Half-maximal inhibition of 125I-epidermal growth factor (EGF) binding to T24 and HT1376 cells was produced by suramin concentration of approximately 300 and 100 microM, respectively. The corresponding value for 125I-insulin-like growth factor 1 (IGF1) binding was 60 microM for both cell lines. Inhibition of T24 and HT1376 growth was virtually complete at suramin concentrations in the range achievable clinically.