Jiřina Škorpíková

Ultrasonically induced alterations of cultured tumour cells

OBJECTIVE The aim of this study was to establish: (i) which phase of the cell cycle is most sensitive to ultrasonic action; and (ii) whether and in which way ultrasound can influence components of the cytoskeleton. METHODS HeLa cell monolayers grown on glass cover-slips in DEM medium were used in all experiments. For proliferation studies, the cell monolayers were trypsinized and the cells were resuspended in fresh medium. The structure of the cytoskeleton was studied by means of the indirect immunofluorescence method. The cells were sonicated by a cw ultrasound of 0.8 MHz at low SA intensities (50, 100 and 500 mW/cm2) for 5 and 10 min. RESULTS The analysis of proliferation demonstrated that cells were most sensitive when undergoing M- and S-phases of the cell cycle. The ultrasonically induced disassembly of cytoskeleton components was most marked in microtubules and microfilaments due to depolymerization of basic proteins (tubulin and actin). The reaction of intermediate filaments was distinctly weaker. CONCLUSIONS In-vitro treatment of tumour cells with low intensity ultrasound results in partial inhibition of proliferation as well as in partial disassembly of all components of the cytoskeleton. Ultrasonically induced changes of the cytoskeleton seem to be non-specific and temporary.

Biological effects of combined ultrasound and cisplatin treatment on ovarian carcinoma cells

The effects of low-power ultrasound, the anti-cancer drug cisplatin, and their combined application were studied in two lines of human ovarian carcinoma cells, A2780 and A2780cis. Four modes of treatment were used: exposure to ultrasonic field, application of cisplatin, exposure to ultrasound followed by cisplatin, and presence of cisplatin followed by exposure to application ultrasound. Ultrasound was used at intensities of 0.5 W/cm(2) and 1.0 W/cm(2) for 10 min, cisplatin was applied at concentrations of 1 microM and 6 microM per cell suspension treated in A2780 and cisplatin-resistant A2780cis cells, respectively. The results of each experimental treatment were assessed by the resultant cell viability related to the viability of control cells, using a standard MTT test. It was shown that a combined effect of ultrasound and cisplatin was more effective than that of ultrasound or cisplatin alone. It also appeared that the order of application played a role, with the cisplatin-ultrasound treatment lowering cell viability more than the ultrasound-cisplatin treatment. It can be assumed that the exposure of cells to a low-power ultrasonic field has an immediate effect on the structure of cell surfaces and, consequently, on entry of cisplatin into the cell. The study also included observations on changes in the cell cycle associated with the treatments used in both cell lines and their evaluation by flow cytometry.

Ultrasound and Cisplatin Combined Treatment of Human Melanoma Cells A375—the Study of Sonodynamic Therapy

Sonodynamic therapy, an effect of low-power ultrasound field and the anticancer drug cisplatin, was studied in vitro on human melanoma cells A375. The viability of cells has been studied by standard 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide viability assay according to different modes of treatment: application of cisplatin alone, exposure of ultrasound field alone, exposure to ultrasound followed by cisplatin and application of cisplatin followed by exposure to ultrasound. Ultrasound was used at a therapeutic intensity of 1 W∙cm(-2) for 10 min. Concentration of cisplatin in the cell suspension was always 2.3 μM. The results show that sonodynamic therapy is one of the possibilities of how to intensify standard cytostatic therapy. This conclusion is supported by reducing the viability of studied cells, especially 72 h after the treatment. The time sequence of application of ultrasonic field and cytostatics appears to be a significant factor affecting the changes in cell viability. Maximum suppression of viability has been found when applying the experimental design involving application of cisplatin followed by exposure to ultrasound; the final value of viability of combined affected cells was more than 10% lower than for cisplatin treatment alone.