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Establishment of Proliferative Tetraploid Cells from Nontransformed Human Fibroblasts
10:04

Establishment of Proliferative Tetraploid Cells from Nontransformed Human Fibroblasts

Published on: January 8, 2017

ATM and p21 cooperate to suppress aneuploidy and subsequent tumor development

Kate C Shen1, Henry Heng, Yaolin Wang

  • 1Barbara Ann Karmanos Cancer Institute, Detroit, Michigan 48201, USA.

Cancer Research
|October 6, 2005
PubMed

Insights

The protein kinase ATM is crucial for DNA repair. Loss of ATM and p21 accelerates cancer by increasing chromosomal instability, with p21 acting as a tumor suppressor.

Area of Science:

  • Molecular Biology
  • Genetics
  • Cancer Research

Background:

  • The DNA damage checkpoint protein kinase ATM (ataxia telangiectasia mutated) is vital for sensing DNA damage and regulating cell cycle progression and DNA repair.
  • Atm-/- cells exhibit defects in proliferation via the Arf/p53/p21 pathway, contributing to chromosomal instability (CIN).

Purpose of the Study:

  • To investigate the role of p21 in suppressing chromosomal instability and tumor development in the context of ATM deficiency.
  • To elucidate the specific mechanisms by which p21 influences genome stability in Atm-deficient cells.

Main Methods:

  • Comparative analysis of Atm-/- p21-/- mice with Atm-/- and p21-/- counterparts.
  • Assessment of chromosomal instability (CIN) in primary embryonic fibroblasts using techniques to detect chromatid breaks and aneuploidy.
  • Evaluation of karyokinesis and metaphase-anaphase transition in Atm-deficient cells.

Main Results:

  • Atm-/- p21-/- mice showed increased predisposition to carcinomas and sarcomas with intratumoral heterogeneity.
  • Atm-deficient cells displayed defects in metaphase-anaphase transition, leading to abnormal karyokinesis.
  • Atm-/- p21-/- fibroblasts exhibited significantly higher CIN, characterized by increased chromatid breaks and aneuploidy, compared to single-knockout cells.
  • p21 suppressed numerical CIN but not structural CIN in the ATM-deficient background.

Conclusions:

  • Increased p21 expression in Atm-/- cells acts as a defense mechanism against CIN and tumor formation.
  • Aneuploidy development precedes tumor formation in a genome instability background.
  • p21 functions as a critical tumor suppressor in the context of ATM loss-induced genome instability.

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