Role of mTOR in anticancer drug resistance: perspectives for improved drug treatment

Drug Resist Updat. 2008 Jun;11(3):63-76. doi: 10.1016/j.drup.2008.03.001. Epub 2008 Apr 28.


The mammalian target of rapamycin (mTOR) pathway plays a central role in regulating protein synthesis, ribosomal protein translation, and cap-dependent translation. Deregulations in mTOR signaling are frequently associated with tumorigenesis, angiogenesis, tumor growth and metastasis. This review highlights the role of the mTOR in anticancer drug resistance. We discuss the network of signaling pathways in which the mTOR kinase is involved, including the structure and activation of the mTOR complex and the pathways upstream and downstream of mTOR as well as other molecular interactions of mTOR. Major upstream signaling components in control of mTOR activity are PI3K/PTEN/AKT and Ras/Raf/MEK/ERK pathways. We discuss the central role of mTOR in mediating the translation of mRNAs of proteins related to cell cycle progression, those involved in cell survival such as c-myc, hypoxia inducible factor 1* (HIF-1*) and vascular endothelial growth factor (VEGF), cyclin A, cyclin dependent kinases (cdk1/2), cdk inhibitors (p21(Cip1) and p27(Kip1)), retinoblastoma (Rb) protein, and RNA polymerases I and III. We then discuss the potential therapeutic opportunities for using mTOR inhibitors rapamycin, CCI-779, RAD001, and AP-23573 in cancer therapy as single agents or in combinations to reverse drug resistance.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Antineoplastic Agents / pharmacology
  • Antineoplastic Agents / therapeutic use*
  • Apoptosis / physiology
  • Cell Cycle / physiology
  • Drug Resistance, Neoplasm / drug effects
  • Drug Resistance, Neoplasm / physiology*
  • Humans
  • Neoplasms / drug therapy*
  • Neoplasms / metabolism
  • Protein Biosynthesis
  • Protein Conformation
  • Protein Kinase Inhibitors / pharmacology
  • Protein Kinase Inhibitors / therapeutic use*
  • Protein Kinases / chemistry
  • Protein Kinases / physiology*
  • Signal Transduction
  • TOR Serine-Threonine Kinases


  • Antineoplastic Agents
  • Protein Kinase Inhibitors
  • Protein Kinases
  • MTOR protein, human
  • TOR Serine-Threonine Kinases