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Establishment of Proliferative Tetraploid Cells from Nontransformed Human Fibroblasts
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Establishment of Proliferative Tetraploid Cells from Nontransformed Human Fibroblasts

Published on: January 8, 2017

The expression of the DeltaNp73beta isoform of p73 leads to tetraploidy

E Marrazzo1, S Marchini, M Tavecchio

  • 1Laboratory of Molecular Pharmacology, Department of Oncology, Istituto di Ricerche Farmacologiche Mario Negri, Via La Masa 19, 20156 Milan, Italy.

European Journal of Cancer (Oxford, England : 1990)
|November 15, 2008
PubMed

Insights

Over-expressing DeltaNp73beta in lung cancer cells suppressed growth and caused cell death. It also led to genomic instability, tetraploidy, and mitotic catastrophe, revealing its role in cell cycle regulation.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Cell Biology

Background:

  • The p73 gene locus encodes numerous isoforms, including DeltaN truncated variants.
  • DeltaNp73 isoforms may have distinct cellular activities.
  • The specific role of DeltaNp73beta in cell cycle and mitosis requires further investigation.

Purpose of the Study:

  • To investigate the function of DeltaNp73beta by examining the effects of its over-expression in tumor cell models.
  • To understand the impact of DeltaNp73beta on cell growth, genomic stability, and cell death pathways.

Main Methods:

  • Utilized a tetracycline-inducible expression system for DeltaNp73beta over-expression.
  • Studied the human lung carcinoma cell line H1299.
  • Analyzed cell growth, genomic stability, cell morphology, mitotic figures, and cell death mechanisms.

Main Results:

  • DeltaNp73beta over-expression suppressed cell growth and induced cell death in H1299 cells.
  • Stable over-expression led to impaired genomic stability, resulting in tetraploid cells.
  • Cells exhibited enlarged size, multinucleation, aberrant mitotic figures, and died via apoptotic-independent pathways (mitotic catastrophe).

Conclusions:

  • DeltaNp73beta over-expression triggers aberrant mitosis, evading mitotic spindle checkpoint control.
  • This leads to tetraploidy and cell death through mitotic catastrophe, not apoptosis.
  • The C-terminal region of DeltaNp73, particularly the beta isoform, appears crucial for regulating cell growth and mitosis.

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