Related Experiment Video

Updated: Aug 19, 2025

Yeast As a Chassis for Developing Functional Assays to Study Human P53
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Yeast As a Chassis for Developing Functional Assays to Study Human P53

Published on: August 4, 2019

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PPM1D suppresses p53-dependent transactivation and cell death by inhibiting the Integrated Stress Response

Zdenek Andrysik1,2, Kelly D Sullivan3,4, Jeffrey S Kieft5

  • 1Linda Crnic Institute for Down Syndrome, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA. zdenek.andrysik@cuanschutz.edu.

Nature Communications
|December 1, 2022
PubMed

Insights

Dual inhibition of p53 repressors MDM2 and PPM1D amplifies the p53 pathway, enhancing cancer cell death. This approach targets the integrated stress response for improved cancer therapy efficacy.

Area of Science:

  • Molecular Biology
  • Cancer Biology
  • Pharmacology

Background:

  • The p53 transcription factor is crucial for cellular stress response but is inhibited by MDM2 and PPM1D.
  • Current cancer therapies targeting p53 repressors show limited efficacy due to insufficient tumor cell death induction.

Purpose of the Study:

  • To investigate the synergistic effects of dual MDM2 and PPM1D inhibition on cancer cell apoptosis.
  • To elucidate the role of the eIF2α-ATF4 pathway in mediating the anti-cancer effects of dual inhibition.

Main Methods:

  • Utilized pharmacological inhibitors of MDM2 and PPM1D in various cancer cell types.
  • Assessed apoptosis induction, p53 transcriptional activity, and eIF2α-ATF4 pathway activation.
  • Evaluated tumor growth inhibition in mouse models.

Main Results:

  • Dual inhibition of MDM2 and PPM1D significantly induced apoptosis in cancer cells.
  • PPM1D inhibition promoted eIF2α phosphorylation and ATF4 accumulation, enhancing p53 activity.
  • Combined inhibition depleted heme and activated HRI-dependent eIF2α phosphorylation, leading to synergistic cell death and tumor growth suppression in vivo.

Conclusions:

  • PPM1D negatively regulates both the p53 network and the integrated stress response (eIF2α-ATF4 pathway).
  • Dual inhibition of MDM2 and PPM1D represents a promising therapeutic strategy for cancer treatment.
  • Targeting the eIF2α-ATF4 pathway alongside p53 repression offers significant therapeutic potential.

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