Characterization of the activity of the PI3K/mTOR inhibitor XL765 (SAR245409) in tumor models with diverse genetic alterations affecting the PI3K pathway

Mol Cancer Ther. 2014 May;13(5):1078-91. doi: 10.1158/1535-7163.MCT-13-0709. Epub 2014 Mar 14.


Activation of the PI3K (phosphoinositide 3-kinase) pathway is a frequent occurrence in human tumors and is thought to promote growth, survival, and resistance to diverse therapies. Here, we report pharmacologic characterization of the pyridopyrimidinone derivative XL765 (SAR245409), a potent and highly selective pan inhibitor of class I PI3Ks (α, β, γ, and δ) with activity against mTOR. Broad kinase selectivity profiling of >130 protein kinases revealed that XL765 is highly selective for class I PI3Ks and mTOR over other kinases. In cellular assays, XL765 inhibits the formation of PIP(3) in the membrane, and inhibits phosphorylation of AKT, p70S6K, and S6 phosphorylation in multiple tumor cell lines with different genetic alterations affecting the PI3K pathway. In a panel of tumor cell lines, XL765 inhibits proliferation with a wide range of potencies, with evidence of an impact of genotype on sensitivity. In mouse xenograft models, oral administration of XL765 results in dose-dependent inhibition of phosphorylation of AKT, p70S6K, and S6 with a duration of action of approximately 24 hours. Repeat dose administration of XL765 results in significant tumor growth inhibition in multiple human xenograft models in nude mice that is associated with antiproliferative, antiangiogenic, and proapoptotic effects.

MeSH terms

  • Animals
  • Antineoplastic Agents / administration & dosage
  • Antineoplastic Agents / pharmacology*
  • Cell Line, Tumor
  • Cell Movement / drug effects
  • Disease Models, Animal
  • Humans
  • Inhibitory Concentration 50
  • Mice
  • Neoplasms / drug therapy
  • Neoplasms / genetics*
  • Neoplasms / metabolism*
  • Neoplasms / pathology
  • Neovascularization, Pathologic
  • Phosphatidylinositol Phosphates / metabolism
  • Phosphoinositide-3 Kinase Inhibitors*
  • Phosphorylation
  • Protein Kinase Inhibitors / administration & dosage
  • Protein Kinase Inhibitors / pharmacology*
  • Proto-Oncogene Proteins c-akt / metabolism
  • Quinoxalines / administration & dosage
  • Quinoxalines / pharmacology*
  • Ribosomal Protein S6 Kinases / metabolism
  • Signal Transduction / drug effects*
  • Sulfonamides / administration & dosage
  • Sulfonamides / pharmacology*
  • TOR Serine-Threonine Kinases / antagonists & inhibitors*
  • Xenograft Model Antitumor Assays


  • Antineoplastic Agents
  • Phosphatidylinositol Phosphates
  • Phosphoinositide-3 Kinase Inhibitors
  • Protein Kinase Inhibitors
  • Quinoxalines
  • Sulfonamides
  • XL765
  • phosphatidylinositol 3,4,5-triphosphate
  • Proto-Oncogene Proteins c-akt
  • Ribosomal Protein S6 Kinases
  • TOR Serine-Threonine Kinases