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p73 tumor-suppressor activity is impaired in human thyroid cancer

Francesco Frasca1, Veronica Vella, Alessandra Aloisi

  • 1Dipartimento di Medicina Interna e di Medicina Specialistica - Endocrinologia, Università di Catania, 95123 Catania.

Cancer Research
|October 3, 2003
PubMed

Insights

The p73 protein, crucial for DNA repair, is often lost in thyroid cancer. Its impaired function, due to interactions with other proteins, contributes to thyroid malignancies, suggesting p73 as a therapeutic target.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Oncology

Background:

  • The p53 protein family plays a critical role in cell cycle regulation and apoptosis.
  • Loss of p53 function is linked to the progression of well-differentiated thyroid cancer to aggressive forms.
  • The involvement of p73, another p53 family member, in thyroid carcinogenesis was investigated.

Purpose of the Study:

  • To investigate the role of the p73 protein in thyroid cancer development.
  • To determine if p73 function is impaired in thyroid malignancies.
  • To explore p73 as a potential therapeutic target for thyroid cancer.

Main Methods:

  • Analysis of p73 expression in normal thyrocytes and thyroid tumors.
  • Assessment of p73 responsiveness to DNA-damaging agents in thyroid cancer cells.
  • Investigation of p73 interactions with p73 variants (DeltaNp73) and mutant p53.

Main Results:

  • Normal thyrocytes lack p73 expression, while most thyroid malignancies show p73 positivity.
  • Thyroid cancer cells' p73 protein is unresponsive to DNA damage, failing to induce cell cycle arrest or apoptosis.
  • Overexpression of active p73 in thyroid cancer lines induced cell cycle arrest but not cell death.
  • Functional impairment of p73 is partly due to interactions with DeltaNp73 and mutant p53.

Conclusions:

  • Functional impairment of p73 is implicated in thyroid cancer development.
  • p73's inability to induce apoptosis in cancer cells, despite cell cycle arrest, highlights its compromised role.
  • p73 represents a potential therapeutic target for thyroid cancer treatment.

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