Multiple effects of electroporation on the adhesive behaviour of breast cancer cells and fibroblasts.

Viktoria N Pehlivanova,Iana H Tsoneva,Rumiana D Tzoneva

doi:10.1186/1475-2867-12-9

Abstract

BackgroundRecently electroporation using biphasic pulses was successfully applied in clinical developments for treating tumours in humans and animals. We evaluated the effects of electrical treatment on cell adhesion behaviour of breast cancer cells and fibroblasts. By applying bipolar electrical pulses we studied short- and long-lived effects on cell adhesion and survival, actin cytoskeleton and cell adhesion contacts in adherent cancer cells and fibroblasts.MethodsTwo cancer cell lines (MDA-MB-231 and MCF-7) and one fibroblast cell line 3T3 were used. Cells were exposed to high field intensity (200 - 1000 V/cm). Cell adhesion and survival after electrical exposure were studied by crystal violet assay and MTS assay. Cytoskeleton rearrangement and cell adhesion contacts were visualized by actin staining and fluorescent microscope.ResultsThe degree of electropermeabilization of the adherent cells elevated steadily with the increasing of the field intensity. Adhesion behaviour of fibroblasts and MCF-7 was not significantly affected by electrotreatment. Interestingly, treating the loosely adhesive cancer cell line MDA-MB-231 with 200 V/cm and 500 V/cm resulted in increased cell adhesion. Cell replication of both studied cancer cell lines was disturbed after electropermeabilization. Electroporation influenced the actin cytoskeleton in cancer cells and fibroblasts in different ways. Since it disturbed temporarily the actin cytoskeleton in 3T3 cells, in cancer cells treated with lower and middle field intensity actin cytoskeleton was well presented in stress fibers, filopodia and lamellipodia. The electrotreatment for cancer cells provoked preferentially cell-cell adhesion contacts for MCF-7 and cell-ECM contacts for MDA-MB- 231.ConclusionsCell adhesion and survival as well as the type of cell adhesion (cell-ECM or cell-cell adhesion) induced by the electroporation process is cell specific. The application of suitable electric pulses can provoke changes in the cytoskeleton organization and cell adhesiveness, which could contribute to the restriction of tumour invasion and thus leads to the amplification of anti-tumour effect of electroporation-based tumour therapy.

Highlights

Electroporation using biphasic pulses was successfully applied in clinical developments for treating tumours in humans and animals
The aim of the present paper is to study the effect of the applied biphasic electrical pulses (200 1000 V/cm) on the adhesive behaviour of two breast cancer cell lines and a non-transformed fibroblast cell line in order to elucidate the effect of electrical field on tumour progression
Degree of cell electroporation Penetration of Propidium iodide (PI) into the cells was used to define the success of permeabilization of the cell membrane by the process of electroporation

Summary

Introduction

Electroporation using biphasic pulses was successfully applied in clinical developments for treating tumours in humans and animals. Most of the electropermeabilization protocols use unipolar electrical pulses [5,6,7], but exploited to increase transport of chemotherapeutic drugs through the plasma membrane into the tumour cells. This process is called electrochemotherapy [1] and it is widely used for the treatment of accessible human tumours and tumour lesions [15,16,17,18]. Not as selective as electrochemotherapy, the thermal ablation can be used as a minimally invasive surgical procedure to ablate cancer tissue without the use of potentially harmful chemotherapeutic drugs

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