Fostriecin sodium

Fostriecin is a potent inhibitor of the serine/threonine protein phosphatases PP2A and PP4 with IC₅₀ value of 3.2 and 3 nM, respectively. It also displays weak inhibition of topoisomerase II having IC₅₀ of 40 μM and PP1 with IC₅₀ of 131 μM. Fostriecin has antitumor activity against a wide spectrum of tumor cells in vitro and excellent activity against P388 and L1210 leukemias in vivo.