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STAT3 blockade with shRNA enhances radiosensitivity in Hep-2 human laryngeal squamous carcinoma cells
Xiaoming Li1, Hairu Wang, Xiuying Lu
1Department of Otolaryngology-Head and Neck Surgery, Bethune International Peace Hospital, Shijiazhuang, Hebei Province, PR China. xmlmo@126.com
Abstract:
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.
Insights
Targeting Signal transducer and activator of transcription 3 (STAT3) with siRNA enhances radiation therapy effectiveness in laryngeal cancer cells. This approach significantly increases cell death and reduces tumor cell proliferation, offering a promising strategy for cancer treatment.
Area of Science:
- Oncology
- Molecular Biology
- Radiotherapy Research
Background:
- Signal transducer and activator of transcription 3 (STAT3) is frequently overexpressed and activated in various human cancers, promoting tumor growth and survival.
- STAT3 activation is implicated in resistance to cancer therapies, including radiation therapy.
- Hep-2 human laryngeal squamous carcinoma cells provide a model system to investigate therapeutic resistance mechanisms.
Purpose of the Study:
- To investigate the potential of combining STAT3 targeting small interfering RNA (siRNA) with radiation therapy to enhance the radiosensitivity of Hep-2 cells.
- To evaluate the effects of STAT3 siRNA and radiation on cell proliferation, apoptosis, and key protein expression levels in Hep-2 cells.
Main Methods:
- Construction of a STAT3-targeting recombinant plasmid and transfection into Hep-2 cells using Lipofectamine 2000.
- Validation of STAT3 mRNA down-regulation using semiquantitative RT-PCR.
- Assessment of cell proliferation via MTT assay after combined treatment with STAT3 siRNA and gamma irradiation.
- Analysis of cell apoptosis using flow cytometry (FCM) following irradiation.
- Quantification of protein levels (STAT3, p-STAT3, Bcl-2, VEGF, p53) using Western blotting or similar techniques.
Main Results:
- STAT3 siRNA effectively reduced STAT3 mRNA levels in Hep-2 cells.
- Combined treatment with STAT3 siRNA and radiation significantly decreased Hep-2 cell proliferation (P<0.05).
- STAT3 siRNA and radiation significantly increased Hep-2 cell apoptosis in a time-dependent manner after 6 Gy irradiation (P<0.05).
- The combined treatment led to decreased protein levels of STAT3, p-STAT3, Bcl-2, VEGF, and p53.
- Strong positive correlations were observed between p-STAT3 levels and Bcl-2, VEGF, and p53 levels (r=0.974, 0.988, 0.976, all P<0.01).
Conclusions:
- Specific siRNA targeting STAT3 enhances the radiosensitivity of Hep-2 human laryngeal squamous carcinoma cells.
- This enhancement is achieved by modulating the expression of key proteins involved in cell survival and apoptosis, including Bcl-2, VEGF, and p53.
- Combining STAT3 inhibition with radiation therapy represents a potential therapeutic strategy for laryngeal cancer.
