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E2F4 loss suppresses tumorigenesis in Rb mutant mice

Eunice Y Lee1, Hieu Cam, Ulrike Ziebold

  • 1Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.

Cancer Cell
|December 25, 2002
PubMed

Insights

Loss of E2F4, a key repressive transcription factor, prevents tumor development in mice lacking the retinoblastoma protein (pRB). This occurs through a novel mechanism involving p107 and p130 regulating other E2F factors.

Area of Science:

  • * Molecular Biology
  • * Cancer Biology
  • * Genetics

Background:

  • * E2F transcription factors regulate cell cycle genes.
  • * Retinoblastoma protein (pRB) and its relatives (p107, p130) are tumor suppressors.
  • * E2F4 is a major repressive E2F family member.

Purpose of the Study:

  • * To investigate the role of E2F4 in pRB's tumor-suppressive function.
  • * To understand the mechanism by which E2F4 loss impacts tumorigenesis.

Main Methods:

  • * Analysis of Rb(+/-) mice with and without E2F4.
  • * Biochemical analyses of E2F complexes.
  • * Assessment of gene expression and cell proliferation in pRB-deficient cells.

Main Results:

  • * E2F4 loss significantly suppressed pituitary and thyroid tumor development in Rb(+/-) mice.
  • * E2F4 deficiency prevented aberrant gene expression and proliferation in pRB-deficient cells.
  • * A novel mechanism was identified where E2F4 loss enables p107 and p130 to regulate pRB-specific activator E2Fs.

Conclusions:

  • * E2F4 plays a critical role in pRB-mediated tumor suppression.
  • * Novel E2F complexes involving p107/p130 and activator E2Fs are important in regulating tumorigenesis.
  • * Targeting E2F4 could be a therapeutic strategy for pRB-deficient cancers.

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