Investigation of effect of applied nanosecond pulsed electric fields on tumor

Abstract

Induction of apoptosis by application of nanosecond pulsed electric fields (nsPEFs) on eukaryotic cells has been confirmed, and then the cancer treatment using the nsPEFs has been investigated. In this study, in vivo experiments have employed embryonic chick assay to apply nsPEFs to solid tumors. The embryonic chick assay can prepare a large number of samples with facility, in comparison to unexceptional animal experiments. The tumor cells: EMT6/KU (mouse breast adenocarcinoma cells), were planted on chorioallantoic membrane (CAM) in chicken egg from an aperture of the shell. The 2ns-PEFs were applied on the formed solid tumor by using a pulsed power generator. The solid tumors were dissected from the CAM and weighted three days after the nsPEFs application. The mean weight of the pulse-treated tumors was significantly smaller than that of controls which were not exposed nsPEFs. To understand the phenomena in the solid tumor, the apoptotic test using the florescence activated cell sorting (FACS) based on flow cytometry was performed on cell suspension applied nsPEFs in cuvette (in vitro). The viability of tumor cells was measured by the WST-1 assay (water soluble tetrazolium salts) in advance. The viability of pulse-treated samples was significantly smaller than that of controls. When the apoptosis test was performed for the samples obtained on this condition, it was found with the FACS that apoptosis was induced and necrosis would occur simultaneously in cells with nsPEFs.