Comparison of cell membrane damage induced by the therapeutic ultrasound on human breast cancer MCF-7 and MCF-7/ADR cells

• Membrane damage caused by ultrasound was compared between MCF-7 and MCF-7/ADR cells.
• The ultrasound induced cell membrane damage showed an intensity-dependent manner.
• MCF-7/ADR was more sensitive to ultrasound than MCF-7 at the same conditions.
• The decline of membrane fluidity in MCF-7/ADR might contribute to its susceptibility.

ObjectivesThe aim of this study was to compare the cell membrane damage induced by ultrasound at different intensities between MCF-7/ADR cells and MCF-7 cells.MethodsTumor cells in the culture dishes (35 mm diameter) were exposed to planner ultrasound at intensities range from 0.25 W/cm2 to 0.75 W/cm2 for 60 s. The viability of cells was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and Guava Viacount assay. The cell membrane integrity was estimated by flow cytometry using propidium iodide (PI) staining and cellular uptake of fluorescein isothiocyanate-dextran (FD500). The membrane lipid peroxidation and membrane fluidity were also specially compared between two cell lines in this paper using spectrophotometry. Ultrastructural alterations on membrane surface were observed by scanning electron microscopy.ResultsThe ultrasound produced cytotoxicity in both cell lines increased with the irradiation intensity increased from 0.25 W/cm2 to 0.75 W/cm2. Cell membrane permeability and the level of lipid peroxidation were remarkably enhanced after ultrasound application. In addition, relatively severe cell damage was observed under scanning electron microscopy after 0.75 W/cm2 ultrasound treatment.ConclusionsUltrasound exposure decreased MCF-7 and MCF-7/ADR cell viability in an intensity-dependent manner and MCF-7/ADR cells were more sensitive to ultrasound exposure than MCF-7 cells at the same experimental conditions. The declined membrane fluidity in MCF-7/ADR cell may be one of the reasons for its increased membrane damage.