[a cyclic polyether ionophore extracted from the black sponge Halichondria; inhibits protein phosphatases such as Cdc25 which serve as off switches for cell proliferation, and therefore acts as a tumor promoter; NLM also lists as a vasoconstrictor. ( CSP )] (UMLS (CSP) C0069389) =Organic Chemical; Hazardous or Poisonous Substance ; =ETHER; marine toxin; Tumor Promoter; animal extract; phosphatase inhibitor;