Studies on the mechanism of phosphatidylinositol 3-kinase inhibition by wortmannin and related analogs

J Med Chem. 1996 Mar 1;39(5):1106-11. doi: 10.1021/jm950619p.


Wortmannin, a fungal metabolite, was identified as a potent inhibitor (IC50 = 4.2 nM) of phosphatidylinositol 3-kinase (PI 3-kinase). Due to the importance of PI 3-kinase in several intracellular signaling pathways, structure-activities studies on wortmannin analogs were performed in an effort to understand the structural requirements necessary for PI 3-kinase inhibition. Since wortmannin is an irreversible inhibitor of PI 3-kinase, it was postulated that covalent attachment at the electrophilic C-21 site was a possible mode of action for PI 3-kinase inhibition. We have prepared various wortmannin analogs which address the possibility of this mechanism. Of particular interest are compounds which affect the C-21 position of wortaminnin either sterically or electronically. Our results support the conclusion that nucleophilic addition by the kinase onto the C-21 position of wortmannin is required for inhibition of PI 3-kinase by wortmannin analogs. Additionally, we have prepared several D-ring analogs of wortmannin, and their activities are reported herein. We conclude that the wortmannin D ring is an important recognition site since modifications have such a dramatic effect on inhibitor potency. Finally, the identification of 17beta-hydroxywortmannin represents the first reported subnanomolar inhibitor of PI 3-kinase. These studies, along with in vivo antitumor experiments, suggest that the mechanism of PI 3-kinase inhibition correlates to the associated toxicity observed with wortmannin-based inhibitors of PI 3-kinase.

MeSH terms

  • Androstadienes / chemistry*
  • Androstadienes / pharmacology*
  • Androstadienes / therapeutic use
  • Animals
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology*
  • Antineoplastic Agents / therapeutic use
  • Crystallography, X-Ray
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology*
  • Humans
  • Mammary Neoplasms, Experimental / drug therapy
  • Mice
  • Models, Molecular
  • Molecular Conformation
  • Molecular Structure
  • Neoplasm Transplantation
  • Phosphatidylinositol 3-Kinases
  • Phosphotransferases (Alcohol Group Acceptor) / antagonists & inhibitors*
  • Structure-Activity Relationship
  • Thermodynamics
  • Tumor Cells, Cultured
  • Wortmannin


  • Androstadienes
  • Antineoplastic Agents
  • Enzyme Inhibitors
  • Phosphatidylinositol 3-Kinases
  • Phosphotransferases (Alcohol Group Acceptor)
  • Wortmannin