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Updated: Aug 2, 2025
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Studying Cell Cycle-regulated Gene Expression by Two Complementary Cell Synchronization Protocols
Published on: June 6, 2017
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PPM1D activity promotes the replication stress caused by cyclin E1 overexpression
Andra S Martinikova1, Miroslav Stoyanov1, Anna Oravetzova1
1Laboratory of Cancer Cell Biology, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic.
Molecular Oncology
|April 17, 2023
Summary
Increased protein phosphatase magnesium-dependent 1 delta (PPM1D) activity exacerbates replication stress and genome instability in cancer cells with cyclin E1 overexpression. Inhibiting PPM1D rescues these effects, suggesting a therapeutic target.
Area of Science:
- Molecular Biology
- Cancer Biology
- Genetics
Background:
- Oncogene-induced replication stress is a key driver of cancer genome instability.
- Cyclin E1 overexpression (CCNE1 amplification) and Protein phosphatase magnesium-dependent 1 delta (PPM1D) dysregulation are common in various cancers.
- PPM1D negatively regulates p53 and cell cycle checkpoints, promoting tumorigenesis.
Purpose of the Study:
- To investigate the role of PPM1D activity in enhancing replication stress caused by cyclin E1.
- To elucidate the mechanisms by which PPM1D influences replication dynamics and genome integrity.
Main Methods:
- Utilized cell models with CCNE1 overexpression and truncated PPM1D mutants.
- Assessed cell cycle progression, DNA replication origin licensing, and transcription-replication collisions.
- Analyzed replication fork speed and DNA copy number alterations.
- Employed pharmacological inhibition of PPM1D.
Main Results:
- Truncated PPM1D accelerated G1 to S phase transition and impaired origin licensing.
- CCNE1-induced transcription-replication collisions and replication fork slowing were amplified by truncated PPM1D.
- Pharmacological PPM1D inhibition rescued replication speed and reduced DNA copy number alterations.
Conclusions:
- Elevated PPM1D activity exacerbates CCNE1-driven replication stress and genome instability.
- PPM1D likely suppresses p53 checkpoint function, promoting cancer progression.
- PPM1D inhibition represents a potential therapeutic strategy for cancers with CCNE1 oncogene activation.
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