Suramin is a polysulfonated naphthylurea that inhibits the binding of calmodulin to recognition sites on the ryanodine receptor-1 (IC50 = 4.9 μM), blocks G protein coupling to GPCRs, and non-selectively antagonizes P2 purinergic receptors (10-100 μM). Suramin also acts as a non-specific competitor of glycosaminoglycan binding to a variety of targets including TGFβ, PDGF, and FGF and additionally inhibits insulin-like growth factor-l, EGF, PKC activity, TNF, IL-2, transferrin, and Apo-B. While originally used as an early stage treatment of trypanosome-caused onchocerciasis (African river blindness) and African trypanosomiasis (African sleeping sickness), suramin has been under clinical evaluation for its potential to regress a number of cancer cell lines, including non-small cell lung cancer, advanced breast cancer, hormone refractory prostate cancer, metastatic renal cell cancer, colorectal cancer, and high-grade gliomas.
