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Cold-inducible RNA-binding protein bypasses replicative senescence in primary cells through extracellular

Ana Artero-Castro1, Francisco B Callejas, Josep Castellvi

  • 1Pathology Department, Fundació Institut de Recerca Hospital Vall d'Hebron, Passeig Vall d'Hebron 119-129, 08035 Barcelona, Spain.

Molecular and Cellular Biology
|January 23, 2009
PubMed

Insights

Cold-inducible RNA-binding protein (CIRP) enables primary cells to bypass senescence by activating ERK1/2 signaling. This discovery offers new insights into cell proliferation and potential cancer research applications.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Cancer Research

Background:

  • Embryonic stem cells (ESCs) exhibit high proliferation rates, similar to cancer cells.
  • Understanding ESC gene expression in primary cells is crucial for regenerative medicine and cancer studies.
  • Replicative senescence limits the lifespan of primary cells, posing a barrier to their therapeutic use.

Purpose of the Study:

  • To identify embryonic stem cell genes that can overcome replicative senescence in primary cells.
  • To elucidate the molecular mechanisms by which identified genes influence cell proliferation and senescence.
  • To explore the potential relevance of these findings in cancer biology.

Main Methods:

  • Genetic screening of mouse embryonic fibroblasts (MEFs) infected with an ESC cDNA library.
  • Investigating the role of Cold-inducible RNA-binding protein (CIRP) in cellular senescence.
  • Utilizing MEK inhibitors to assess the involvement of extracellular signal-regulated kinase 1 and 2 (ERK1/2) pathway.
  • Analyzing protein synthesis pathways (S6, 4E-BP1) and cell cycle regulators (cyclin D1-CDK4).

Main Results:

  • CIRP was identified as a key factor enabling primary cells to bypass senescence.
  • CIRP promotes cell proliferation by enhancing ERK1/2 phosphorylation.
  • CIRP's function involves stimulating general protein synthesis via S6 and 4E-BP1, increasing cyclin D1-CDK4 activity.
  • CIRP bypasses senescence independently of p16(INK4a), p21(WAF1), and p19(ARF) upregulation.

Conclusions:

  • CIRP is a novel factor that can induce immortalization of primary cells by activating the ERK1/2 pathway.
  • CIRP's mechanism of action provides a new model for understanding senescence bypass.
  • Upregulation of CIRP in some cancers suggests its potential role in tumorigenesis and warrants further investigation.

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