Suramin, an anti-cancer drug, inhibits protein kinase C and induces differentiation in neuroblastoma cell clone NB2A.

Protein kinase C purified from rat brain was found to be inhibited by suramin, a substance used originally in the therapy of antitrypanosomic infections and more recently proposed as antineoplastic agent. The inhibition of suramin was competitive with one of the substrates of the enzyme, ATP with a Ki of 10 microM. At concentrations adequate to inhibit the isolated enzyme, suramin was shown to slow the rate of proliferation of neuroblastoma NB2A cells in vitro and to induce their differentiation as evidenced by typical morphological changes.