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Polyamine depletion induces G1 and S phase arrest in human retinoblastoma Y79 cells

Akiko Ueda1, Makoto Araie, Shunichiro Kubota

  • 1Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan. aueda-tky@umin.ac.jp

Cancer Cell International
|January 23, 2008
PubMed
Abstract

Insights

DL-alpha-difluoromethylornithine (DFMO) inhibits cell proliferation in retinoblastoma Y79 cells by arresting them in G1 and S phases. This occurs through p107 dephosphorylation and p107/E2F-4 complex accumulation.

Area of Science:

  • Cell biology
  • Molecular oncology
  • Biochemistry

Background:

  • Polyamines and ornithine decarboxylase (ODC) are crucial for cell proliferation.
  • DL-alpha-difluoromethylornithine (DFMO), an ODC inhibitor, causes G1 arrest via retinoblastoma protein (pRb) dephosphorylation.
  • The impact of DFMO on pRb-deficient cells remained uninvestigated.

Purpose of the Study:

  • To investigate the effects of DFMO on pRb-deficient human retinoblastoma Y79 cell proliferation.
  • To elucidate the molecular mechanisms underlying DFMO's action in these cells.

Main Methods:

  • Cultured Y79 cells were utilized.
  • Techniques included polyamine analysis, western blot, gel shift, FACS, and promoter analysis.

Main Results:

  • DFMO suppressed Y79 cell proliferation, leading to G1 and S phase accumulation.
  • DFMO induced p27/Kip1 protein expression.
  • DFMO caused p107 dephosphorylation and accumulation of the p107/E2F-4 complex.

Conclusions:

  • p107 dephosphorylation is implicated in the G1 and S phase arrest observed in DFMO-treated Y79 cells.
  • The accumulation of the p107/E2F-4 complex is involved in DFMO-induced cell cycle arrest.

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