Ultrasound exposure in the presence of hematoporphyrin induced loss of membrane integral proteins and inactivity of cell proliferation associated enzymes in sarcoma 180 cells in vitro

Emerging Sonodynamic Therapy-Based Nanomedicines for Cancer Immunotherapy

Cancer immunotherapy effect can be greatly enhanced by other methods to induce immunogenic cell death (ICD), which has profoundly affected immunotherapy as a highly efficient paradigm. However, these treatments have significant limitations, either by causing damage of the immune system or limited to superficial tumors. Sonodynamic therapy (SDT) can induce ICD to promote immunotherapy without affecting the immune system because of its excellent spatiotemporal selectivity and low side effects. Nevertheless, SDT is still limited by low reactive oxygen species yield and the complex tumor microenvironment. Recently, some emerging SDT-based nanomedicines have made numerous attractive and encouraging achievements in the field of cancer immunotherapy due to high immunotherapeutic efficiency. However, this cross-cutting field of research is still far from being widely explored due to huge professional barriers. Herein, the characteristics of the tumor immune microenvironment and the mechanisms of ICD are firstly systematically summarized. Subsequently, the therapeutic mechanism of SDT is fully summarized, and the advantages and limitations of SDT are discussed. The representative advances of SDT-based nanomedicines for cancer immunotherapy are further highlighted. Finally, the application prospects and challenges of SDT-based immunotherapy in future clinical translation are discussed.

An overview of therapeutic applications of ultrasound based on synergetic effects with gold nanoparticles and laser excitation

Acoustic cavitation which occurs at high intensities of ultrasound waves can be fatal for tumor cells. The existence of dissolved gases and also the presence of nanoparticles (NPs) in a liquid, irradiated by ultrasound, decrease the acoustic cavitation onset threshold and the resulting bubbles collapse. On the other hand, due to unique capabilities and optical properties of gold nanoparticles (GNPs), they have been emphasized as effective NPs in the field of tumor therapy. Absorption of the laser light by GNPs causes the water molecules around the NPs to evaporate and produces vapor cavities. In this paper, we have reviewed published studies in the fields of ultrasound therapy, sonodynamic therapy (SDT) and synergism of low-level ultrasound and also laser radiation in the presence of GNPs.

Spectroscopic investigation on the sonodynamic damage to protein in the presence of eosine B

In this work, bovine serum albumin (BSA) and eosine B (EB) were selected as a model protein and sonosensitizer, respectively. The sonodynamic damage to protein in the presence of EB and its mechanism were studied by means of absorption and fluorescence spectra. The results indicated that the synergistic effects of ultrasound and EB can efficiently damage the BSA molecules, and the damage of protein could be mainly due to the generation of reactive oxygen species (ROS). The damage degree of protein increased with the increase of ultrasonic time and EB concentration because of the increased quantities of ROS. Hydroxyl free radical (OH) was the major mediators of the ultrasound-inducing proteins damage in the presence of EB. In addition, the quantities of ROS from the diphenylcarbazide (DPCI)-EB solutions and the DPCI-fluorescein (FS) solutions with or without ROS scavengers were contrasted, respectively. The results show that FS mainly produce OH, but the quantities of ROS in the presence of FS were lower than those of EB, which indicates that the nitro and bromine substituent groups on the benzene ring of FS increase the quantity of ROS, but do not change the kinds of ROS.

Evaluation of fractionated and repeated sonodynamic therapy by using dual frequency for murine model of breast adenocarcinoma

Background

Sonodynamic therapy (SDT) is a new approach for cancer treatment. Repair by reoxygenation induces cell damage in all treatment which uses photo- and sonosensitizers. In this study, the in vivo antitumor effect of dual-frequency sonication is investigated at low-level intensity and hematoporphyrin (Hp). It is used for the treatment of spontaneous breast adenocarcinoma of Balb/c mice with a variety of dose repetition and fractionation regimes.

Methods

Eighty tumor-bearing mice were divided into eight groups, the control group (A); the sham group (B); the injection of Hp alone group (C); 30-min dual-frequency sonication with Hp injection in one repetition at the first day group (D); two repetitions at the first and sixth days group (E); three repetitions at the first, sixth, and twelfth days group (F); four repetitions at the first, sixth, twelfth, and eighteenth days (30 min/repetition) group (G); and the fractional treatment group treated by dual-frequency sonication and Hp injection at the first, third, sixth, and ninth days (7.5 min/fraction) (H). For each group, the tumor growth delay was calculated during 30 days after treatment. These tumors were studied histopathologically.

Results

The results show that the treatment with ultrasound dose repetition in two, three, and four times (E, F, and G groups) were effective in delaying tumor growth compared with one-time sonication (D group) (p < 0.05). Also, the ultrasound dose fractionation is more effective in decreasing the tumor growth rate compared with the ultrasound dose repetition in four repeats and in one repeat from the 12th to the 30th day (p < 0.05). Histopathological studies indicated that the mitotic activity of tumor cells was reduced following treatment with four fraction and four repetition protocols.

Conclusion

The ultrasound dose fractionation and repetition technique with dual-frequency sonication can have a useful therapeutic effect in sonodynamic therapy with the possibility of use in future clinical applications.

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.

Sonodynamic therapy induces the interplay between apoptosis and autophagy in K562 cells through ROS

Sonodynamic therapy (SDT) is a relatively new approach in the treatment of various cancers including leukemia cells. The aim of this study is to investigate the occurrence of apoptosis and autophagy after treated by protoporphyrin IX (PpIX)-mediated SDT (PpIX-SDT) on human leukemia K562 cells as well as the relationship between them. Firstly, mitochondrial-dependent apoptosis was observed through morphological observation and biochemical analysis. Meanwhile, SDT was shown to induce autophagy in K562 cells, which caused an increase in EGFP-LC3 puncta cells, a conversion of LC3 II/I, formation of acidic vesicular organelles (AVOs) and co-localization between LC3 and LAMP2 (a lysosome marker). Besides, pretreatment with autophagy inhibitor 3-MA or bafilomycin A1 was shown to provide protection against autophagy and to enhance SDT-induced apoptosis and necrosis, while the apoptosis suppressor z-VAD-fmk failed to affect formation of autophagic vacuoles or partially prevented SDT-induced cytotoxicity, which suggested that SDT-induced autophagy functioned as a survival mechanism. Additionally, this study reported apparent apoptosis and autophagy with dependence on intracellular reactive oxygen species (ROS) production. Preliminary data showed that ROS scavenger N-acetylcysteine (NAC) effectively blocked the SDT induced accumulation of ROS, reversed sono-damage, cell apoptosis and autophagy. Taken together, these data indicate that autophagy may be cytoprotective in our experimental system, and the ROS caused by PpIX-SDT treatment may play an important role in initiating apoptosis and autophagy.

Sonodynamically induced anti-tumor effect of 5-aminolevulinic acid on pancreatic cancer cells

Sonodynamic therapy (SDT), a promising modality for cancer treatment, involves the synergistic interaction of ultrasound and some chemical compounds termed sonosensitizers. However, its effect on pancreatic cancer cells remains unclear. In our study, we sought to identify the cytotoxic effects of ultrasound-activated 5-aminolevulinic acid on human pancreatic cancer Capan-1 cells. Cell viability was determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide) analysis; mitochondrial membrane potential was assessed using the fluorescent probe jc-1; apoptosis was evaluated by flow cytometry; cell morphology was investigated by scanning electron microscopy; apoptosis-related protein expression was analyzed by Western blot assay. We found that SDT significantly decreased the survival rate of cells, and this effect increased with 5-aminolevulinic acid concentration and ultrasound exposure time. The mechanism underlying the effect of SDT involves, in part, the induction of a conspicuous loss in mitochondrial membrane potential and, in part, the induction of apoptosis through upregulation of Bax expression, downregulation of Bcl-2 and increased activation of procaspase-3. These results indicate that the ultrasonically induced cell killing effect could be enhanced by 5-ALA and that the mitochondrial pathway might be involved in the cell damage process. We conclude that SDT is a promising new methodology for pancreatic cancer treatment.

Use of ultrasound in drug delivery systems: emphasis on experimental methodology and mechanisms

Recent studies have shown that ultrasound energy could be applied for targeting or controlling drug release. This new concept of therapeutic ultrasound combined with drugs has induced a great amount of interest in various medical fields. In this paper, several experimental systems are cited in which ultrasound is being utilized to evaluate new application of this modality. The mechanisms of ultrasound-mediated drug delivery are discussed in addition to the review of current advances in the use of ultrasound in systems involving research in cancer therapy, gene therapy, microbubbles and other drug delivery in vitro and in vivo experiments.

A novel nanosonosensitizer for sonodynamic therapy: in vivo study on a colon tumor model

OBJECTIVES

The particles in a liquid decrease the ultrasonic intensity threshold needed for cavitation onset. In this study, a new nanoconjugate composed of protoporphyrin IX and gold nanoparticles was used as a nucleation site for cavitation. The nonradiative relaxation time of protoporphyrin IX in the presence of gold nanoparticles is longer than the similar time without gold nanoparticles.

METHODS

This study was conducted on colon carcinoma tumors in BALB/c mice. The tumor-bearing mice were randomly divided into 6 groups (each containing 15 mice): (1) control, (2) protoporphyrin IX, (3) gold nanoparticle-protoporphyrin IX conjugate, (4) ultrasound alone, (5) ultrasound + protoporphyrin IX, and (6) ultrasound + gold nanoparticle-protoporphyrin IX conjugate. In the respective groups as indicated above, protoporphyrin IX or the gold nanoparticle-protoporphyrin IX conjugate was injected into the tumors. Ultrasound irradiation was performed on the tumors 24 hours after injection. Antitumor effects were estimated by evaluation of the relative tumor volume, doubling time, and 5-folding time for the tumors after treatment. The cumulative survival fraction of the mice and percentage of the lost tissue volume (treated) were also assessed in the different groups.

RESULTS

A significant difference in the average relative volumes of the tumors 13 days after treatment was found between the ultrasound + gold nanoparticle-protoporphyrin IX group and the other groups (P < .05). The longest doubling and 5-folding times were observed in the ultrasound + gold nanoparticle-protoporphyrin IX and ultrasound + protoporphyrin IX groups.

CONCLUSIONS

Protoporphyrin IX conjugated to gold nanoparticles has been introduced as a promising compound and a new sonosensitizer for improving the tumor response to sonodynamic therapy by reducing the relative tumor volume and increasing the cumulative survival fraction.

Oxidation-extraction spectrometry of reactive oxygen species (ROS) generated by chlorophyllin magnesium (Chl-Mg) under ultrasonic irradiation

In order to examine the mechanism and process of sonodynamic reaction, the chlorophyllin magnesium (Chl-Mg) acting as a sonosensitizer was irradiated by ultrasound, and the generation of reactive oxygen species (ROS) were detected by the method of oxidation-extraction spectrometry (OES). That is, under ultrasonic irradiation in the presence of Chl-Mg, the 1,5-diphenyl carbazide (DPCI) is oxidized by generated ROS into 1,5-diphenyl carbazone (DPCO), which can be extracted by mixed organic solvent and display a obvious visible absorption at 563 nm wavelength. Besides, the generation conditions of ROS were also reviewed. The results demonstrated that the quantities of generated ROS increased with the increase of ultrasonic irradiation time, Chl-Mg concentration and DPCI concentration. Finally, several radical scavengers (l-Histidine (His), 2,6-Di-tert-butyl-methylphenol (BHT) and Vitamin C (VC)) were used to determine the kind of the generated ROS. It was found that at least the hydroxyl radical (OH) and singlet oxygen (1O2) were generated in the presence of Chl-Mg under ultrasonic irradiation. It is wish that this paper might offer some valuable references for the study on the mechanism of SDT and the application of Chl-Mg in tumor treatment.

Detection and comparison of reactive oxygen species (ROS) generated by chlorophyllin metal (Fe, Mg and Cu) complexes under ultrasonic and visible-light irradiation

In this paper, in order to examine the mechanisms of sonodynamic and photodynamic reactions, the chlorophyllin metal (Chl-M (M=Fe, Mg and Cu)) complexes were irradiated by ultrasound (US) and visible-light (VL), respectively, and the generation of reactive oxygen species (ROS) were detected by the method of Oxidation-Extraction Spectrometry (OES). That is, the 1,5-diphenyl carbazide (DPCI) is oxidized by the generated ROS into 1,5-diphenyl carbazone (DPCO), which can display a various visible absorption around 563 nm wavelength. Besides, some influence parameters on the generation of ROS were also reviewed. The results demonstrated an apparent synergistic effect of Chl-M and ultrasonic or visible-light irradiation for the generation of ROS. Moreover, the quantities of generated ROS increase with the increase of (ultrasonic or visible-light) irradiation time and Chl-M (M=Fe, Mg and Cu) concentration. Finally, several quenchers were used to determine the kind of the generated ROS. It is wished that this paper might offer some valuable references for the study on the sonodynamic therapy (SDT) and photodynamic therapy (PDT) mechanisms and the application of Chl-M in tumor treatment.

Exploiting ultrasound-mediated effects in delivering targeted, site-specific cancer therapy

Although the concept of employing ultrasound for the treatment of cancer is not a new one, virtually all existing ultrasound-based clinical cancer treatments are based on hyperthermic ablation. This review seeks to highlight the potential offered by more subtle ultrasound-triggered phenomena such as sonoporation in delivering novel targeted cancer treatment modalities.