Molecular dissection of AKT activation in lung cancer cell lines

Mol Cancer Res. 2013 Mar;11(3):282-93. doi: 10.1158/1541-7786.MCR-12-0558. Epub 2013 Jan 14.

Abstract

AKT is a critical signaling node downstream of phosphoinositide 3-kinase (PI3K), which is often activated in cancer. We analyzed the state of activation of AKT in 80 human non-small cell lung carcinoma cell lines under serum starvation conditions. We identified 13 lines, which showed persistent AKT activation in the absence of serum. In 12 of 13 lines, AKT activation could be attributed to loss of PTEN, activating mutation in EGF receptor (EGFR) or PIK3CA, or amplification of ERBB2. HCC2429 was the only cell line that had no alterations in those genes, but had high phospho-AKT(Ser473) levels under serum starvation conditions. However, the activation of AKT in HCC2429 was PI3K- and mTOR complex 2 (mTORC2)-dependent based upon use of specific inhibitors. Kinome tyrosine phosphorylation profiling showed that both Notch and SRC were highly activated in this cell line. Despite the activation of Notch, AKT activation and cell survival were not affected by Notch inhibitors DAPT or compound E. In contrast, SRC inhibitors PP2 and dasatinib both significantly decreased pAKT(Ser473) levels and reduced cell survival by inducing apoptosis. Furthermore, a combination of SRC and mTOR inhibition synergistically blocked activation of AKT and induced apoptosis. Overexpression of SRC has been identified previously in human lung cancers, and these results suggest that a combination of SRC and mTOR inhibitors may have unique therapeutic benefit for a subset of lung cancers with these molecular features.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Apoptosis / genetics
  • Carrier Proteins / metabolism
  • Cell Line, Tumor
  • Cell Survival / genetics
  • ErbB Receptors / metabolism
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Lung Neoplasms / genetics*
  • Lung Neoplasms / metabolism
  • Mechanistic Target of Rapamycin Complex 2
  • Multiprotein Complexes / metabolism*
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphorylation
  • Proto-Oncogene Proteins c-akt / genetics*
  • Proto-Oncogene Proteins c-akt / metabolism
  • Receptors, Notch / genetics
  • Signal Transduction
  • TOR Serine-Threonine Kinases / metabolism*
  • src-Family Kinases / genetics

Substances

  • Carrier Proteins
  • Multiprotein Complexes
  • PTER protein, human
  • Receptors, Notch
  • EGFR protein, human
  • ErbB Receptors
  • src-Family Kinases
  • Mechanistic Target of Rapamycin Complex 2
  • Proto-Oncogene Proteins c-akt
  • TOR Serine-Threonine Kinases