Ultrasound and cisplatin combined treatment of human melanoma cells A375--the study of sonodynamic therapy

Bystander Effect of Therapeutic Ultrasound in the Presence of Cisplatin: An in Vitro Study on Human Melanoma Cells

Background

In the bystander effect, non-irradiated cells receive biological signals from adjacent irradiated cells and undergo a variety of alterations, considered recently in non-ionizing irradiation like ultrasound waves. In this study, the bystander effect of therapeutic ultrasound exposure alone and in combination with cisplatin was determined.

Objective

This study aims to determine the bystander effect caused by ultrasound and cisplatin.

Material and Methods

This experimental study was conducted on the human melanoma cell line including two groups of target and bystander cells. The target cell group was divided into three sub-groups of ultrasound irradiation alone, cisplatin alone, and ultrasound irradiation in the presence of cisplatin that the culture medium of these three groups of cells was transferred to the bystander cell group using the medium transfer technique. Then, apoptotic bystander cells and the expression of P53 and HO-1 in target and bystander groups were measured.

Results

The results of the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and apoptosis assay showed that cell death in target and bystander groups receiving the ultrasound with cisplatin is higher than in the ultrasound without cisplatin. PCR (the polymerase chain reaction) results in the target and bystander groups receiving treatments with increased expression of the P53 gene. Target and bystander groups receiving the ultrasound without cisplatin showed a decrease in HO-1 gene expression, while the ultrasound with cisplatin showed an increase in the HO-1 gene compared to the control group.

Conclusion

Combining ultrasound with ultrasound and without it can transfer bystander signals to the cells that are not directly treated.

Sonodynamic therapy: Ultrasound parameters and in vitro experimental configurations

Sonodynamic therapy (SDT) is a new therapeutic modality for noninvasive cancer treatment based on the association of ultrasound and sonosensitizer drugs. Up to date, there is not a consensus on the standardization of the experimental conditions for the in vitro studies to correctly assess cell viability during SDT. Therefore, this review article mainly describes how the main ultrasound parameters and experimental setups of ultrasound application in vitro studies can influence the SDT bioeffects/response. The sonodynamic action is impacted by the combination of frequency, intensity, duty cycle, and ultrasound application time. The variation of experimental setups in cell culture, such as the transducer position, cell-transducer distance, coupling medium thickness, or type of culture, also influences the sonodynamic response. The intensity, duty cycle, and sonication duration increase cytotoxicity and reactive oxygen species production. For similar ultrasound parameters, differences in the experimental configuration impact cell death in vitro. Four main experimental setups are used to assess for SDT in cell culture (i) a planar transducer placed directly in contact with the bottom of the culture microplate; (ii) microplate positioned in the transducer's far-field using a water tank; (iii) sealed cell culture tubes immersed in water away from the transducer; and (iv) transducer dipped directly into the well with cell culture. Because of the significant variations in the experimental setups, sonodynamic response can significantly vary, and the translation of these results for in vivo experimentation is difficult. Therefore, a well-designed and detailed in vitro experimental setup is vital for understanding the interactions among the biological medium, the sonosensitizer, and the ultrasound for the in vitro to in vivo translation in SDT.

Effect of shock waves combined with cytostatics on the growths of tumors in vivo

Based on their field of application, the physical parameters of shock waves differ. Experiments referred to in this article used tandem shock waves generated on the surface of a composite anode. There, individual pores of the anode produce multichannel discharges. The composite anode may have a variety of shapes, which, consequently, influence the arrangement of the entire apparatus and the area of their application. Experiments referred to in this article utilise an anode divided into two parts that generated tandem shock waves. The previously conducted experiments have clearly shown that the effect of a tandem shock wave can be very well localized in the focal area, causing necrosis and apoptosis of the tumor cells, and enhancing the effect of cytostatics. This study investigated the effect of tandem shock waves with concomitantly administered cytostatics. We conducted our experiments on Lewis rats. The rats were injected with syngeneic sarcoma tumor cells intradermally and caudally on both the right and left sides. The highest rate of tumor growth inhibition was observed in the cisplatin-treated group that was subsequently treated with shock waves. The effect of shock waves on cell membranes is well described as they increase their permeability due to sonodynamic effect induced by cavitation. The results of experiments referred to in this article conducted in vivo in experimental animals enable us to note that the shock wave increases the effect of chemotherapy administered.

A Macro Lens-Based Optical System Design for Phototherapeutic Instrumentation

Light emitting diode (LED) and ultrasound have been powerful treatment stimuli for tumor cell growth due to non-radiation effects. This research is the first preliminary study of tumor cell suppression using a macro-lens-supported 460-nm LED combined with high-frequency ultrasound. The cell density, when exposed to the LED combined with ultrasound, was gradually reduced after 30 min of induction for up to three consecutive days when 48-W DC, 20-cycle, and 50 V_p-p sinusoidal pulses were applied to the LEDs through a designed macro lens and to the ultrasound transducer, respectively. Using a developed macro lens, the non-directional light beam emitted from the LED could be localized to a certain spot, likewise with ultrasound, to avoid additional undesirable thermal effects on the small sized tumor cells. In the experimental results, compared to LED-only induction (14.49 ± 2.73%) and ultrasound-only induction (13.27 ± 2.33%), LED combined with ultrasound induction exhibited the lowest cell density (6.25 ± 1.25%). Therefore, our measurement data demonstrated that a macro-lens-supported 460-nm LED combined with an ultrasound transducer could possibly suppress early stage tumor cells effectively.

A review of low-intensity ultrasound for cancer therapy

The literature describing the use of low-intensity ultrasound in four major areas of cancer therapy-sonodynamic therapy, ultrasound-mediated chemotherapy, ultrasound-mediated gene delivery and anti-vascular ultrasound therapy-was reviewed. Each technique consistently resulted in the death of cancer cells, and the bio-effects of ultrasound were attributed primarily to thermal actions and inertial cavitation. In each therapeutic modality, theranostic contrast agents composed of microbubbles played a role in both therapy and vascular imaging. The development of these agents is important as it establishes a therapeutic-diagnostic platform that can monitor the success of anti-cancer therapy. Little attention, however, has been given either to the direct assessment of the mechanisms underlying the observed bio-effects or to the viability of these therapies in naturally occurring cancers in larger mammals; if such investigations provided encouraging data, there could be prompt application of a therapy technique in the treatment of cancer patients.

Protein damage and reactive oxygen species generation induced by the synergistic effects of ultrasound and methylene blue

The sonodynamic damage to protein in the presence of methylene blue (MB) and the various influencing factors including ultrasonic irradiation time and MB concentration on the damage of protein were studied by fluorescence and absorption spectra. In addition, the mechanisms of the synergistic effects of ultrasound and MB were studied by oxidation-extraction photometry with several reactive oxygen species (ROS) scavengers. The results indicated that the damage of protein induced by the synergistic effects of ultrasound and MB were more serious than those that ultrasound or MB alone was applied. The damage of protein could be mainly due to the generation of ROS. The damage degree of protein increased with the increase of ultrasonic irradiation time and MB concentration because of the increased quantities of ROS generation. Both (1)O₂ and ·OH were the important mediators of the ultrasound-inducing protein damage in the presence of MB.