Identification of antrocin from Antrodia camphorata as a selective and novel class of small molecule inhibitor of Akt/mTOR signaling in metastatic breast cancer MDA-MB-231 cells

Chem Res Toxicol. 2011 Feb 18;24(2):238-45. doi: 10.1021/tx100318m. Epub 2010 Dec 15.

Abstract

The PI3K/Akt/mTOR pathway is considered to be an attractive target for the development of novel anticancer molecules. This paper reports for the first time that a small molecule, antrocin (MW = 234), from Antrodia camphorata was a potent antagonist in various cancer types, being highest in metastatic breast cancer MDA-MB-231 cells (MMCs) with an IC(50) value of 0.6 μM. Antrocin was a superior antiproliferator in MMCs as compared with doxorubicin and cisplatin, prevents colony formation, and was nontoxic to nontumorgenic MCF10A and HS-68 cells. Antrocin induced dose-dependent apoptosis in MMCs and caused cleavage of caspase-3 and poly(ADP-ribose) polymerase. Antrocin also caused a time-dependent decrease in protein expression of anti-apoptotic Bcl-2, Bcl-xL, survivin, and their mRNA, with concomitant increase in pro-apoptotic Bax and cytosolic cytochrome c. In a mechanistic study, antrocin suppressed the phosphorylation of Akt and its downstream effectors mTOR, GSK-3β, and NF-κB. Furthermore, down-regulation of Akt by small interfering RNA prior to antrocin treatment resulted in enhanced cell growth inhibition and apoptosis. Thus, antrocin as an Akt/mTOR dual inhibitor has broad applicability in the development of a clinical trial candidate for the treatment of metastatic breast cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / isolation & purification
  • Antineoplastic Agents / pharmacology*
  • Antrodia / chemistry*
  • Apoptosis / drug effects
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / secondary
  • Cell Proliferation / drug effects
  • Female
  • Glycogen Synthase Kinase 3 / antagonists & inhibitors
  • Glycogen Synthase Kinase 3 / metabolism
  • Glycogen Synthase Kinase 3 beta
  • Humans
  • Lactones / chemistry
  • Lactones / isolation & purification
  • Lactones / pharmacology*
  • Models, Molecular
  • NF-kappa B / antagonists & inhibitors
  • NF-kappa B / metabolism
  • Neoplasms / drug therapy
  • Proto-Oncogene Proteins c-akt / antagonists & inhibitors
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Sesquiterpenes / chemistry
  • Sesquiterpenes / isolation & purification
  • Sesquiterpenes / pharmacology*
  • Signal Transduction / drug effects
  • TOR Serine-Threonine Kinases / antagonists & inhibitors
  • TOR Serine-Threonine Kinases / metabolism*

Substances

  • Antineoplastic Agents
  • Lactones
  • NF-kappa B
  • Sesquiterpenes
  • antrocin
  • TOR Serine-Threonine Kinases
  • GSK3B protein, human
  • Glycogen Synthase Kinase 3 beta
  • Proto-Oncogene Proteins c-akt
  • Glycogen Synthase Kinase 3