[Effects of suramin on cell proliferation of various types of human malignant cells]

Suramin, a polyanionic compound used clinically for the treatment of African trypanosomiosis and onchocerciasis, has been shown to inhibit the action of various growth factors such as platelet-derived growth factor, epidermal growth factor, fibroblast growth factor and transforming growth factor-beta to stimulate DNA synthesis of cells. Therefore, we investigated effects of suramin on cell proliferation of various types of human malignant cells in culture. Cell lines used were as follows: cervical cancer (HeLa), mammary cancer (MCF-7), bladder cancer (EJ), hepatoma (HuH-7, PLC/PRF/5), embryonal carcinoma (PA-1), and three in vitro transformed human fibroblast lines (KMST-6, SUSM-1, and VA-13). A serum-free defined medium, ASF103, was used when the effect of suramin on proliferation of cells was investigated. This culture medium contains only bovine serum albumin (0.1%), transferrin (5 micrograms/ml) and insulin (5 micrograms/ml) as peptide factors. On day 1, the drug was added to culture medium at the concentration of 25-100 micrograms/ml and 72-96 hr later, the number of cells was counted. The growth inhibition was expressed as the percentage of cells surviving after treatment of cells with suramin, with survival in the control condition representing 100 percent. Proliferation of HuH-7 cells was prominently inhibited and those of PA-1, PLC/PRF/5 and KMST-6 were moderately inhibited under the same conditions of treatment. On the other hand, other five cell lines were not responsive to up to 100 micrograms/ml suramin.