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

Nanosecond pulsed electric fields (nsPEFs) is a novel non-thermal technology to induce a series of medical and biological effects. It has been proven effective in tumor shrinkage, but few studies focus on its radiosensitization in oral tongue squamous cell carcinoma. The purposes of this study were to evaluate the radiosensitization effect of nsPEFs, alone or combined with radiation, on human oral tongue cancer cell line Tca8113 and investigate the potential antitumor mechanism. Tca8113 cell line was tested by MTT assay for cell proliferation, Colony-forming assay for cell radiosensitivity, Flow cytometry assay for cell cycle distribution, Annexin V-FITC assay for cell apoptosis, Mitochondrial potential assay for mitochondrial membrane potential changes and Total Nitric Oxide Assay for NO production1. When treated alone, nsPEFs had a time and strength dependent cytotoxic effect on Tca8113 cells. The dose-enhancement ratio for combined nsPEFs and radiation was markedly increased (SER=1.453±0.038>1). Especially in the combination treatment group, G2/M phase cells (39.73±0.48) were obviously increased compared with control group (13.34±2.61) and radiation group (32.62±1.96). Additionally, NO production increased after nsPEFs treatment. In conclusion, nsPEFs can enhance the radiosensitivity of Tca8113 cells and this may involve the cell cycle arrest at G2/M phase, cell apoptosis induction and NO production in nsPEFs treated system2. These results suggest nsPEFs may provide a novel approach for radiosensitization in oral tongue squamous cell carcinoma.