Radiosensitization of oral tongue squamous cell carcinoma by nanosecond pulsed electric fields (nsPEFs)

Nanosecond pulsed electric fields (nsPEFs) are a non-thermal and non-toxic technology that induce a myriad of biological effects. They have been proven to be effective in tumor shrinkage, but few studies focus on its radiosensitization in oral tongue squamous cell carcinoma. The purpose of this research was to study the radiosensitization effect of nsPEFs on a human oral tongue cancer cell line Tca8113 and to investigate the potential antitumor mechanism. A Tca8113 cell line was tested respectively by MIT assay, clonogenic assay, flow cytometry assay, annexin V-FITC/PI assay, mitochondrial potential assay and total nitric oxide assay. Our results showed that nsPEFs had a time and field strength dependent inhibition effect on Tca8113 cells. The sensitization enhancement ratio (SER) of nsPEFs was 1.453 +/- 0.038. Furthermore, radiation induced G2/M arrest was augmented by treatment with nsPEFs. We observed many more Tca8113 cells showing early apoptosis after nsPEFs combined with radiotherapy. Additionally, the NO concentration was significantly increased after nsPEFs treatment. These findings indicate that combination of nsPEFs with radiotherapy can enhance the radiosensitivity of Tca8113 cells and nsPEFs could be a potential radiosensitizer for oral tongue squamous cell carcinoma. (C) 2016 Elsevier B.V. All rights reserved.