STAT3 blockade with shRNA enhances radiosensitivity in Hep-2 human laryngeal squamous carcinoma cells

Oncol Rep. 2010 Feb;23(2):345-53.


Signal transducer and activator of transcription 3 (STAT3) is an oncogene aberrantly activated in many human tumors. We studied whether radiation combined with STAT3 siRNA enhances radiosensitivity of Hep-2 human laryngeal squamous carcinoma cells (Hep-2 cells). Firstly, STAT3 targeting recombinant plasmid was constructed. Hep-2 cells were transfected with expression vector of STAT3 siRNA using Lipofectamine 2000. Semiquantitive RT-PCR detected effective STAT3 mRNA down-regulation by STAT3 siRNA. Secondly, Hep-2 cells were radiated with different doses of gamma-rays after transfection with STAT3 small interference RNA (siRNA). MTT assay showed cell proliferation decreased significantly (P<0.05) after STAT3 siRNA transfection combined with radiation. Thirdly, flow cytometry (FCM) demonstrated that cell apoptosis of combined treatment group increased significantly (P<0.05) and exhibited time dependency after 6 Gy irradiation (P<0.05). Simultaneously, STAT3, p-STAT3, Bcl-2, VEGF, p53 protein levels decreased in Hep-2 cells, with positive correlations between level of p-STAT3 and levels of Bcl-2, VEGF, p53, respectively (r=0.974, 0.988, 0.976, all P<0.01). Above all, specific siRNA targeting STAT3 gene is able to enhance the radiosensitivity in Hep-2 cells by regulating expression of Bcl-2, VEGF and p53 proteins.

Publication types

  • Evaluation Study

MeSH terms

  • Apoptosis / drug effects
  • Apoptosis / radiation effects
  • Base Sequence
  • Carcinoma, Squamous Cell / genetics
  • Carcinoma, Squamous Cell / pathology
  • Carcinoma, Squamous Cell / radiotherapy*
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Cell Survival / radiation effects
  • Gene Expression Regulation, Neoplastic / drug effects
  • Humans
  • Laryngeal Neoplasms / genetics
  • Laryngeal Neoplasms / pathology
  • Laryngeal Neoplasms / radiotherapy*
  • Molecular Sequence Data
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • Proto-Oncogene Proteins c-bcl-2 / physiology
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / pharmacology*
  • Radiation Dosage
  • Radiation Tolerance / drug effects*
  • Radiation Tolerance / genetics
  • Radiation-Sensitizing Agents / pharmacology
  • STAT3 Transcription Factor / antagonists & inhibitors*
  • STAT3 Transcription Factor / genetics
  • Transfection
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / physiology
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / physiology


  • Proto-Oncogene Proteins c-bcl-2
  • RNA, Small Interfering
  • Radiation-Sensitizing Agents
  • STAT3 Transcription Factor
  • STAT3 protein, human
  • Tumor Suppressor Protein p53
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A