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STAT3 activation abrogates growth factor dependence and contributes to head and neck squamous cell carcinoma tumor

Taro Kijima1, Hideo Niwa, Richard A Steinman

  • 1Departments of Otolaryngology, University of Pittsburgh School of Medicine and University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15213, USA.

Cell Growth & Differentiation : the Molecular Biology Journal of the American Association for Cancer Research
|August 24, 2002
PubMed

Insights

Constitutive activation of Signal Transducers and Activators of Transcription 3 (STAT3) drives tumor growth in head and neck squamous cell carcinoma (HNSCC). This STAT3 activation promotes cancer progression independently of Epidermal Growth Factor Receptor (EGFR) signaling.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cancer Research

Background:

  • Epidermal growth factor receptor (EGFR) is often upregulated in head and neck squamous cell carcinoma (HNSCC), contributing to uncontrolled cell growth.
  • Previous research linked autocrine EGFR stimulation to constitutive Signal Transducers and Activators of Transcription 3 (STAT3) activation in HNSCC.

Purpose of the Study:

  • To investigate the role of activated STAT3 in HNSCC tumor progression.
  • To determine if STAT3 activation contributes to mitogenic signaling independently of EGFR.

Main Methods:

  • Stable transfection of HNSCC cells with a dominant-active STAT3 construct.
  • Analysis of STAT3 target gene expression (Bcl-X(L), cyclin D1).
  • In vitro proliferation assays and in vivo tumor growth rate assessments.
  • Cell cycle analysis.

Main Results:

  • HNSCC cells with activated STAT3 showed increased expression of target genes like Bcl-X(L) and cyclin D1.
  • These cells exhibited enhanced proliferation in vitro and accelerated tumor growth in vivo.
  • Cell cycle analysis revealed a higher proportion of cells in the G(2)-M phase.

Conclusions:

  • Constitutive STAT3 activation promotes tumor growth in HNSCC.
  • STAT3 contributes to HNSCC progression independently of the EGFR autocrine pathway.

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