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PRAP1 is a novel executor of p53-dependent mechanisms in cell survival after DNA damage

B H Huang1, J L Zhuo, C H W Leung

  • 1Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.

Cell Death & Disease
|December 14, 2012
PubMed

Insights

The tumor suppressor p53 protein upregulates proline-rich acidic protein 1 (PRAP1) in response to DNA damage. PRAP1 promotes cancer cell survival by inducing cell-cycle arrest, offering new insights into p53

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Cancer Research

Background:

  • The p53 protein is a critical regulator of cellular responses to DNA damage.
  • p53 can induce cell cycle arrest, senescence, or apoptosis to maintain genomic stability or eliminate damaged cells.
  • Distinct downstream pathways mediate p53's opposing roles in cell fate determination.

Purpose of the Study:

  • To investigate novel downstream targets of p53 involved in cellular responses to genotoxic stress.
  • To elucidate the role of proline-rich acidic protein 1 (PRAP1) in p53-mediated cell survival pathways.

Main Methods:

  • Induction of DNA damage using chemotherapeutic drugs, gamma irradiation, and hydrogen peroxide.
  • Analysis of PRAP1 gene expression and p53 binding using ChIP assays.
  • Assessment of cancer cell apoptosis and cell-cycle arrest following PRAP1 knockdown.

Main Results:

  • p53 was found to upregulate the novel protein PRAP1 under DNA-damaging conditions.
  • Functional p53-response elements were identified in the PRAP1 gene, confirming PRAP1 as a direct p53 target.
  • PRAP1 induction by p53 promotes cancer cell survival by inhibiting apoptosis and inducing cell-cycle arrest, particularly in response to 5-fluorouracil (5-FU).

Conclusions:

  • PRAP1 is a novel p53 target gene that plays a pro-survival role in cancer cells.
  • p53-mediated induction of PRAP1 contributes to resistance against DNA-damaging chemotherapeutic agents.
  • These findings enhance our understanding of p53's mechanisms in promoting cell survival during cytotoxic treatments.

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