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mTOR inhibition, the second generation: ATP-competitive mTOR inhibitor initiates unexpected receptor tyrosine

Megan Keniry1, Ramon Parsons

  • 1Institute for Cancer Genetics and Herbert Irving Comprehensive Cancer Center, Columbia University, New York, New York 10032, USA.

Cancer Discovery
|May 16, 2012
PubMed

Insights

The kinase inhibitor AZD8055 blocks mTOR signaling, but unexpectedly activates AKT through receptor tyrosine kinases. This finding reveals a feedback loop impacting cancer therapy.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Oncology

Background:

  • The mechanistic target of rapamycin (mTOR) pathway is crucial in cell growth and metabolism.
  • mTOR is frequently dysregulated in various cancers, making it a therapeutic target.
  • Receptor tyrosine kinases (RTKs) play significant roles in cell signaling and cancer progression.

Purpose of the Study:

  • To investigate the effects of the mTOR inhibitor AZD8055 on cellular signaling pathways.
  • To elucidate the mechanism behind AKT activation during mTOR inhibition.
  • To understand the interplay between mTOR, RTKs, and AKT signaling.

Main Methods:

  • Utilized AZD8055, an ATP-competitive kinase inhibitor targeting mTOR.
  • Assessed the activation status of AKT and downstream signaling molecules.
  • Investigated the role of receptor tyrosine kinases in mediating feedback signaling.

Main Results:

  • mTOR inhibition by AZD8055 led to feedback activation of AKT.
  • This AKT activation was dependent on receptor tyrosine kinase signaling.
  • The study identified a specific feedback loop influencing AKT phosphorylation.

Conclusions:

  • AZD8055-induced mTOR inhibition triggers RTK-dependent AKT feedback activation.
  • This feedback mechanism represents a potential resistance pathway in cancer treatment.
  • Targeting this feedback loop may enhance the efficacy of mTOR inhibitors.

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