Author(s): Matta A, DeSouza LV, Ralhan R, Siu KW
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Abstract Patients diagnosed in advanced stages of head and neck squamous cell carcinoma often show limited response to chemotherapeutic agents. Recently, we reported the overexpression of 14-3-3ζ protein in head and neck premalignant and cancer tissues using liquid chromatography-tandem mass spectrometry with isotopic labeling and revealed its significance as a prognostic marker using immunohistochemical analysis. In this study, we determined the potential of 14-3-3ζ as a therapeutic target for head and neck cancer. Small interfering RNA (siRNA) targeting 14-3-3ζ was used to downregulate its expression in head and neck cancer cells in culture. Cell cycle analysis showed that head and neck cancer cells transfected with siRNA targeting 14-3-3ζ showed G(2)-M arrest. These siRNA transfectants also showed increased cell death on treatment with any one of the following chemotherapeutic agents: cisplatin, 5-fluorouracil, paclitaxel, or doxorubicin in comparison with the no transfection controls. Flow cytometric analysis using propidium iodide staining showed increased sub-G(0) fraction in siRNA-transfected cells treated with any of these chemotherapeutic agents, suggesting cell death; in addition, Annexin V staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay revealed increased apoptosis. Taken together, our results strongly showed that downregulation of 14-3-3ζ expression may serve to improve the sensitivity of head and neck cancer cells to chemotherapeutic agents.
This article was published in Mol Cancer Ther
and referenced in Journal of Proteomics & Bioinformatics