Nanosecond Pulses As A Novel Therapy For Human Oral Squamous Cell Carcinoma In Vivo

Malignant tumor is a serious disease which threatens human’s life and has become one of the most serious diseases which harms health and causes death in the world. According to the World Health Organization, Tongue squamous carcinoma is one of the common types of cancer that more than 260,000 people worldwide were affected each year. In recent decades, we have advances in prevention and early diagnosis of medical procedures to other malignant tumor,the mortality from Tongue squamous carcinoma remains high.The five-year survival rate is only50%,the treatment is still a difficult problem.The Pulsed electricfield(PEF) technology whose can cause Intracellular Electromanipulation(IEM)in the cell that is known in recent year. PEF can induce structure and function change in tumor cell.There is the Nanosecond Pulsed Electric Fields( nsPEFs) which acting on the cytomembrane、the organelle membrane and the nuclear membrane in cells.nsPEFs can induce structure and function change in tumor cell is the main pathways that induce cell apoptosis,or programmed cell death.Thus, nanosecond pulsed electric fields(nsPEFs)has shown a bright prospect in cancer treatment.Most achievements on this aspect in the present and previous studies, however, in the confines of the study in vivo.Here we choosed 100 ns,50 kV/cm, 50-200 pulses,1 Hz nanosecond pulsed electric fields(nsPEFs) applied to human TSCC Cal-27 cell xenograft in nude mice to prove the effect on subcutaneous allotransplanted tumor in nude mice, in addition to discuss its possible functional mechanism.. The transplanted tumor models were randomly assigned to 4 groups: control group、50 pulse group 、 100 pulse group and 200 pulse group, 。 nsPEFs treatment, with the pulse parameters(50 kV/cm in amplitude, 100 ns in duration and at a pulse frequency of 1 pulse/s).We exposed the mice in treatment groups a single nsPEFs treatment, tumor morphology was observed with HE staining.The expression of Bax and Bcl-2 protein in cell was detected by immunohistochemistry.After nsPEFs treatment, the tumor volume was significantly smaller in nsPEF groups than control group after treatment(P<0.01).Compared with the nsPEF groups,tumors in control group grew faster and larger.The different parameters of the electric field have different effects ontumors. Immunohistochemical results show that the Bcl- 2 protein expression in nsPEF group was significantly lower than in control group and the expression of Bax was significantly higher in nsPEF group than in control group.The nsPEFs can reduce the proliferative activity and induce cell apoptosis by manipulating the Bax and Bcl-2 genes regulating apoptosis mechanism.Conclusion: These results suggest that nsPEF inhibited significantly the growth of human TSCC Cal-27 cell xenograft in nude mice.Furthermore,the different parameters of pulsed electric fields have different effects on tumors. The main anticancer mechanisms of nsPEF were inducing tumor cells apoptosis, down-regulating the expression of Bcl-2 and up-regulated the Bax.