Hypoxia-selective antitumor agents: norsesterterpene peroxides from the marine sponge Diacarnus levii preferentially suppress the growth of tumor cells under hypoxic conditions.

As part of an ongoing research program to discover natural products that suppress the hypoxia-activated tumor survival pathways, the lipid extract of the Papua New Guinea marine sponge Diacarnus levii was found to suppress hypoxia-induced HIF-1 activation and hypoxic tumor cell survival. Bioassay-guided isolation of D. levii yielded four new norsesterterpene peroxides, diacarnoxides A - D. Diacarnoxide B exhibits a significantly enhanced ability to suppress the growth of tumor cells under hypoxic conditions.