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Characterization of Dynamic Behaviour of MCF7 and MCF10A Cells in Ultrasonic Field Using Modal and Harmonic Analyses.

Geltmeier A, Rinner B, Bade D, Meditz K, Witt R, Bicker U, Bludszuweit-Philipp C, Maier P - PLoS ONE (2015)

Bottom Line: Fractionated treatments by ultrasonic irradiation of suspension myeloid HL60 cells resulted in a significant decrease of viable cells, mostly significant after threefold irradiation in intervals of 3 h.Most importantly in regard to a clinical application, combined ultrasonic treatment and chemotherapy with paclitaxel showed a significantly increased killing of MCF7 cells compared to both monotherapies.The cytotoxic effect of ultrasonic irradiation could be increased by either fractionated treatment or in combination with chemotherapy.

View Article: PubMed Central - PubMed

Affiliation: ASD Advanced Simulation & Design GmbH, Rostock, Germany.

ABSTRACT
Treatment options specifically targeting tumour cells are urgently needed in order to reduce the side effects accompanied by chemo- or radiotherapy. Differences in subcellular structure between tumour and normal cells determine their specific elasticity. These structural differences can be utilised by low-frequency ultrasound in order to specifically induce cytotoxicity of tumour cells. For further evaluation, we combined in silico FEM (finite element method) analyses and in vitro assays to bolster the significance of low-frequency ultrasound for tumour treatment. FEM simulations were able to calculate the first resonance frequency of MCF7 breast tumour cells at 21 kHz in contrast to 34 kHz for the MCF10A normal breast cells, which was due to the higher elasticity and larger size of MCF7 cells. For experimental validation of the in silico-determined resonance frequencies, equipment for ultrasonic irradiation with distinct frequencies was constructed. Differences for both cell lines in their response to low-frequent ultrasonic treatment were corroborated in 2D and in 3D cell culture assays. Treatment with ~ 24.5 kHz induced the death of MCF7 cells and MDA-MB-231 metastases cells possessing a similar elasticity; frequencies of > 29 kHz resulted in cytotoxicity of MCF10A. Fractionated treatments by ultrasonic irradiation of suspension myeloid HL60 cells resulted in a significant decrease of viable cells, mostly significant after threefold irradiation in intervals of 3 h. Most importantly in regard to a clinical application, combined ultrasonic treatment and chemotherapy with paclitaxel showed a significantly increased killing of MCF7 cells compared to both monotherapies. In summary, we were able to determine for the first time for different tumour cell lines a specific frequency of low-intensity ultrasound for induction of cell ablation. The cytotoxic effect of ultrasonic irradiation could be increased by either fractionated treatment or in combination with chemotherapy. Thus, our results will open new perspectives in tumour treatment.

No MeSH data available.


Related in: MedlinePlus

Treatment of MCF7 cells with either (A) ultrasonic irradiation with 23.22 kHz and two different intensities (0.3 W/cm2 or 1 W/cm2, dark grey bars), (B) paclitaxel with 100 nM or 200 nM (light grey bars) or (C) combinations of both treatments (ultrasonic irradiation followed by paclitaxel treatment; white bars) with a) constant concentration of paclitaxel and different intensities of ultrasonic irradiation, and b) constant intensity and different concentrations of paclitaxel.Results represent the means of data from eight independent experiments; the error bars represent the standard errors; p-values were calculated by the two-sided, paired Student’s t- test with * p<0.05, ** p<0.01, *** p<0.001.
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pone.0134999.g008: Treatment of MCF7 cells with either (A) ultrasonic irradiation with 23.22 kHz and two different intensities (0.3 W/cm2 or 1 W/cm2, dark grey bars), (B) paclitaxel with 100 nM or 200 nM (light grey bars) or (C) combinations of both treatments (ultrasonic irradiation followed by paclitaxel treatment; white bars) with a) constant concentration of paclitaxel and different intensities of ultrasonic irradiation, and b) constant intensity and different concentrations of paclitaxel.Results represent the means of data from eight independent experiments; the error bars represent the standard errors; p-values were calculated by the two-sided, paired Student’s t- test with * p<0.05, ** p<0.01, *** p<0.001.

Mentions: In another experiment, we evaluated if the effect of ultrasonic irradiation might be enhanced by a combination with chemotherapy. With this in mind, MCF7 cells were treated by ultrasonic irradiation with 23.22 kHz and either 0.3 W/cm2 or 1 W/cm2 and subsequently cultivated for 48 hours with 100 nM or 200 nM of paclitaxel, one of the standard cytostatic drugs for treatment of breast cancer, (Fig 8) or else treated with paclitaxel followed by ultrasonic irradiation (S3 Fig). Monotherapy with either ultrasonic irradiation (Fig 8A) or paclitaxel (Fig 8B) resulted in a significant reduction of the numbers of vital cells to 63.9% ± 4.6% or 66.5% ± 2.8%, respectively (p = 0.0002 for 1 W/cm2 vs. un-irradiated control; p < 0.0001 for 200 nM vs. un-irradiated control). A further significant decrease with only 47.9% ± 4.5% of vital cells was achieved after combining ultrasonic irradiation with 1 W/cm2 and 200 nM paclitaxel (p = 0.0007 for combination vs. ultrasonic monotherapy; p = 0.002 for combination vs. 200 nM paclitaxel monotherapy) (Fig 8C). The results of the combination treatment in the opposite order (paclitaxel followed by ultrasonic irradiation) showed similar effects (S3 Fig). We again found a significant enhancement of the effects (reduction of proportion of surviving cells) of both monotherapies (67.1% ± 4.8% after irradiation with 1 W/cm2 or 69.8% ± 6.8% treatment with 200 nM paclitaxel) in their combination to only 47.9% ± 5.5% (p = 0.0003 combination vs. ultrasonic monotherapy with 1 W/cm2; p = 0.0008 combination vs. 200 nM paclitaxel monotherapy) (S3A–S3C Fig).


Characterization of Dynamic Behaviour of MCF7 and MCF10A Cells in Ultrasonic Field Using Modal and Harmonic Analyses.

Geltmeier A, Rinner B, Bade D, Meditz K, Witt R, Bicker U, Bludszuweit-Philipp C, Maier P - PLoS ONE (2015)

Treatment of MCF7 cells with either (A) ultrasonic irradiation with 23.22 kHz and two different intensities (0.3 W/cm2 or 1 W/cm2, dark grey bars), (B) paclitaxel with 100 nM or 200 nM (light grey bars) or (C) combinations of both treatments (ultrasonic irradiation followed by paclitaxel treatment; white bars) with a) constant concentration of paclitaxel and different intensities of ultrasonic irradiation, and b) constant intensity and different concentrations of paclitaxel.Results represent the means of data from eight independent experiments; the error bars represent the standard errors; p-values were calculated by the two-sided, paired Student’s t- test with * p<0.05, ** p<0.01, *** p<0.001.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4524665&req=5

pone.0134999.g008: Treatment of MCF7 cells with either (A) ultrasonic irradiation with 23.22 kHz and two different intensities (0.3 W/cm2 or 1 W/cm2, dark grey bars), (B) paclitaxel with 100 nM or 200 nM (light grey bars) or (C) combinations of both treatments (ultrasonic irradiation followed by paclitaxel treatment; white bars) with a) constant concentration of paclitaxel and different intensities of ultrasonic irradiation, and b) constant intensity and different concentrations of paclitaxel.Results represent the means of data from eight independent experiments; the error bars represent the standard errors; p-values were calculated by the two-sided, paired Student’s t- test with * p<0.05, ** p<0.01, *** p<0.001.
Mentions: In another experiment, we evaluated if the effect of ultrasonic irradiation might be enhanced by a combination with chemotherapy. With this in mind, MCF7 cells were treated by ultrasonic irradiation with 23.22 kHz and either 0.3 W/cm2 or 1 W/cm2 and subsequently cultivated for 48 hours with 100 nM or 200 nM of paclitaxel, one of the standard cytostatic drugs for treatment of breast cancer, (Fig 8) or else treated with paclitaxel followed by ultrasonic irradiation (S3 Fig). Monotherapy with either ultrasonic irradiation (Fig 8A) or paclitaxel (Fig 8B) resulted in a significant reduction of the numbers of vital cells to 63.9% ± 4.6% or 66.5% ± 2.8%, respectively (p = 0.0002 for 1 W/cm2 vs. un-irradiated control; p < 0.0001 for 200 nM vs. un-irradiated control). A further significant decrease with only 47.9% ± 4.5% of vital cells was achieved after combining ultrasonic irradiation with 1 W/cm2 and 200 nM paclitaxel (p = 0.0007 for combination vs. ultrasonic monotherapy; p = 0.002 for combination vs. 200 nM paclitaxel monotherapy) (Fig 8C). The results of the combination treatment in the opposite order (paclitaxel followed by ultrasonic irradiation) showed similar effects (S3 Fig). We again found a significant enhancement of the effects (reduction of proportion of surviving cells) of both monotherapies (67.1% ± 4.8% after irradiation with 1 W/cm2 or 69.8% ± 6.8% treatment with 200 nM paclitaxel) in their combination to only 47.9% ± 5.5% (p = 0.0003 combination vs. ultrasonic monotherapy with 1 W/cm2; p = 0.0008 combination vs. 200 nM paclitaxel monotherapy) (S3A–S3C Fig).

Bottom Line: Fractionated treatments by ultrasonic irradiation of suspension myeloid HL60 cells resulted in a significant decrease of viable cells, mostly significant after threefold irradiation in intervals of 3 h.Most importantly in regard to a clinical application, combined ultrasonic treatment and chemotherapy with paclitaxel showed a significantly increased killing of MCF7 cells compared to both monotherapies.The cytotoxic effect of ultrasonic irradiation could be increased by either fractionated treatment or in combination with chemotherapy.

View Article: PubMed Central - PubMed

Affiliation: ASD Advanced Simulation & Design GmbH, Rostock, Germany.

ABSTRACT
Treatment options specifically targeting tumour cells are urgently needed in order to reduce the side effects accompanied by chemo- or radiotherapy. Differences in subcellular structure between tumour and normal cells determine their specific elasticity. These structural differences can be utilised by low-frequency ultrasound in order to specifically induce cytotoxicity of tumour cells. For further evaluation, we combined in silico FEM (finite element method) analyses and in vitro assays to bolster the significance of low-frequency ultrasound for tumour treatment. FEM simulations were able to calculate the first resonance frequency of MCF7 breast tumour cells at 21 kHz in contrast to 34 kHz for the MCF10A normal breast cells, which was due to the higher elasticity and larger size of MCF7 cells. For experimental validation of the in silico-determined resonance frequencies, equipment for ultrasonic irradiation with distinct frequencies was constructed. Differences for both cell lines in their response to low-frequent ultrasonic treatment were corroborated in 2D and in 3D cell culture assays. Treatment with ~ 24.5 kHz induced the death of MCF7 cells and MDA-MB-231 metastases cells possessing a similar elasticity; frequencies of > 29 kHz resulted in cytotoxicity of MCF10A. Fractionated treatments by ultrasonic irradiation of suspension myeloid HL60 cells resulted in a significant decrease of viable cells, mostly significant after threefold irradiation in intervals of 3 h. Most importantly in regard to a clinical application, combined ultrasonic treatment and chemotherapy with paclitaxel showed a significantly increased killing of MCF7 cells compared to both monotherapies. In summary, we were able to determine for the first time for different tumour cell lines a specific frequency of low-intensity ultrasound for induction of cell ablation. The cytotoxic effect of ultrasonic irradiation could be increased by either fractionated treatment or in combination with chemotherapy. Thus, our results will open new perspectives in tumour treatment.

No MeSH data available.


Related in: MedlinePlus