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Yeast As a Chassis for Developing Functional Assays to Study Human P53
14:57

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

Published on: August 4, 2019

MiR-34, SIRT1 and p53: the feedback loop

Munekazu Yamakuchi1, Charles J Lowenstein

  • 1Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA. myamaku1@jhmi.edu

Cell Cycle (Georgetown, Tex.)
|February 18, 2009
PubMed

Insights

The tumor suppressor p53 activates miR-34a, which inhibits SIRT1. This interaction creates a feedback loop, enhancing p53

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Genetics

Background:

  • MicroRNAs (miRNAs) are key regulators of gene expression implicated in tumorigenesis.
  • The TP53 gene, frequently mutated in cancers, encodes p53, which induces miR-34 family members.
  • The miR-34 family's role in cell cycle, senescence, and apoptosis is established, but targets remain incompletely defined.

Purpose of the Study:

  • To investigate the functional relationship between miR-34a and SIRT1.
  • To elucidate the role of SIRT1 in miR-34a-mediated apoptosis.
  • To propose a novel feedback loop involving p53, miR-34a, and SIRT1 in cancer regulation.

Main Methods:

  • Investigated the inhibitory effect of miR-34a on SIRT1 expression.
  • Examined SIRT1's influence on p53 activity and apoptosis.
  • Utilized molecular biology techniques to validate the proposed feedback loop.

Main Results:

  • miR-34a directly inhibits SIRT1, a regulator of cellular senescence and longevity.
  • SIRT1 deacetylates and stabilizes p53, influencing p53-dependent apoptosis.
  • SIRT1 mediates miR-34a's apoptotic effects by modulating p53 activity.

Conclusions:

  • A positive feedback loop exists where p53 induces miR-34a, which suppresses SIRT1, thereby enhancing p53 activity.
  • This regulatory circuit involving p53, miR-34a, and SIRT1 is crucial for apoptosis and may be a target for cancer therapy.

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