Sonodynamically induced apoptosis and active oxygen generation by gallium-porphyrin complex, ATX-70

Nanotechnology-enabled sonodynamic therapy against malignant tumors

Sonodynamic therapy (SDT) is an emerging approach for malignant tumor treatment, offering high precision, deep tissue penetration, and minimal side effects. The rapid advancements in nanotechnology, particularly in cancer treatment, have enhanced the efficacy and targeting specificity of SDT. Combining sonodynamic therapy with nanotechnology offers a promising direction for future cancer treatments. In this review, we first systematically discussed the anti-tumor mechanism of SDT and then summarized the common nanotechnology-related sonosensitizers and their recent applications. Subsequently, nanotechnology-related therapies derived using the SDT mechanism were elaborated. Finally, the role of nanomaterials in SDT combined therapy was also introduced.

Titanium-Based Nanoarchitectures for Sonodynamic Therapy-Involved Multimodal Treatments

Sonodynamic therapy (SDT) has considerably revolutionized the healthcare sector as a viable noninvasive therapeutic procedure. It employs a combination of low-intensity ultrasound and chemical entities, known as a sonosensitizer, to produce cytotoxic reactive oxygen species (ROS) for cancer and antimicrobial therapies. With nanotechnology, several unique nanoplatforms are introduced as a sonosensitizers, including, titanium-based nanomaterials, thanks to their high biocompatibility, catalytic efficiency, and customizable physicochemical features. Additionally, developing titanium-based sonosensitizers facilitates the integration of SDT with other treatment modalities (for example, chemotherapy, chemodynamic therapy, photodynamic therapy, photothermal therapy, and immunotherapy), hence increasing overall therapeutic results. This review summarizes the most recent developments in cancer therapy and tissue engineering using titanium nanoplatforms mediated SDT. The synthesis strategies and biosafety aspects of Titanium-based nanoplatforms for SDT are also discussed. Finally, various challenges and prospects for its further development and potential clinical translation are highlighted.

Ultrasound-Responsive Systems as Components for Smart Materials

Smart materials can respond to stimuli and adapt their responses based on external cues from their environments. Such behavior requires a way to transport energy efficiently and then convert it for use in applications such as actuation, sensing, or signaling. Ultrasound can carry energy safely and with low losses through complex and opaque media. It can be localized to small regions of space and couple to systems over a wide range of time scales. However, the same characteristics that allow ultrasound to propagate efficiently through materials make it difficult to convert acoustic energy into other useful forms. Recent work across diverse fields has begun to address this challenge, demonstrating ultrasonic effects that provide control over physical and chemical systems with surprisingly high specificity. Here, we review recent progress in ultrasound-matter interactions, focusing on effects that can be incorporated as components in smart materials. These techniques build on fundamental phenomena such as cavitation, microstreaming, scattering, and acoustic radiation forces to enable capabilities such as actuation, sensing, payload delivery, and the initiation of chemical or biological processes. The diversity of emerging techniques holds great promise for a wide range of smart capabilities supported by ultrasound and poses interesting questions for further investigations.

Single-cell RNA sequencing reveals the mechanism of sonodynamic therapy combined with a RAS inhibitor in the setting of hepatocellular carcinoma

BACKGROUND

Ras activation is a frequent event in hepatocellular carcinoma (HCC). Combining a RAS inhibitor with traditional clinical therapeutics might be hampered by a variety of side effects, thus hindering further clinical translation. Herein, we report on integrating an IR820 nanocapsule-augmented sonodynamic therapy (SDT) with the RAS inhibitor farnesyl-thiosalicylic acid (FTS). Using cellular and tumor models, we demonstrate that combined nanocapsule-augmented SDT with FTS induces an anti-tumor effect, which not only inhibits tumor progression, and enables fluorescence imaging. To dissect the mechanism of a combined tumoricidal therapeutic strategy, we investigated the scRNA-seq transcriptional profiles of an HCC xenograft following treatment.

RESULTS

Integrative single-cell analysis identified several clusters that defined many corresponding differentially expressed genes, which provided a global view of cellular heterogeneity in HCC after combined SDT/FTS treatment. We conclude that the combination treatment suppressed HCC, and did so by inhibiting endothelial cells and a modulated immunity. Moreover, hepatic stellate secretes hepatocyte growth factor, which plays a key role in treating SDT combined FTS. By contrast, enrichment analysis estimated the functional roles of differentially expressed genes. The Gene Ontology terms "cadherin binding" and "cell adhesion molecule binding" and KEGG pathway "pathway in cancer" were significantly enriched by differentially expressed genes after combined SDT/FTS therapy.

CONCLUSIONS

Thus, some undefined mechanisms were revealed by scRNA-seq analysis. This report provides a novel proof-of-concept for combinatorial HCC-targeted therapeutics that is based on a non-invasive anti-tumor therapeutic strategy and a RAS inhibitor.

Quantitative Proteomics Analysis of FFPE Tumor Samples Reveals the Influences of NET-1 siRNA Nanoparticles and Sonodynamic Therapy on Tetraspanin Protein Involved in HCC

Hepatocellular carcinoma (HCC) poses a severe threat to human health. The NET-1 protein has been proved to be strongly associated with HCC proliferation and metastasis in our previous study. Here, we established and validated the NET-1 siRNA nanoparticles system to conduct targeted gene therapy of HCC xenograft in vivo with the aid of sonodynamic therapy. Then, we conducted a label-free proteome mass spectrometry workflow to analyze formalin-fixed and paraffin-embedded HCC xenograft samples collected in this study. The result showed that 78 proteins were differentially expressed after NET-1 protein inhibited. Among them, the expression of 17 proteins upregulated and the expression of 61 proteins were significantly downregulated. Of the protein abundance, the vast majority of Gene Ontology enrichment terms belong to the biological process. The KEGG pathway enrichment analysis showed that the 78 differentially expressed proteins significantly enriched in 45 pathways. We concluded that the function of the NET-1 gene is not only to regulate HCC but also to participate in a variety of biochemical metabolic pathways in the human body. Furthermore, the protein–protein interaction analysis indicated that the interactions of differentially expressed proteins are incredibly sophisticated. All the protein–protein interactions happened after the NET-1 gene has been silenced. Finally, our study also provides a useful proposal for targeted therapy based on tetraspanin proteins to treat HCC, and further mechanism investigations are needed to reveal a more detailed mechanism of action for NET-1 protein regulation of HCC.

Design and Challenges of Sonodynamic Therapy System for Cancer Theranostics: From Equipment to Sensitizers

As a novel noninvasive therapeutic modality combining low-intensity ultrasound and sonosensitizers, sonodynamic therapy (SDT) is promising for clinical translation due to its high tissue-penetrating capability to treat deeper lesions intractable by photodynamic therapy (PDT), which suffers from the major limitation of low tissue penetration depth of light. The effectiveness and feasibility of SDT are regarded to rely on not only the development of stable and flexible SDT apparatus, but also the screening of sonosensitizers with good specificity and safety. To give an outlook of the development of SDT equipment, the key technologies are discussed according to five aspects including ultrasonic dose settings, sonosensitizer screening, tumor positioning, temperature monitoring, and reactive oxygen species (ROS) detection. In addition, some state-of-the-art SDT multifunctional equipment integrating diagnosis and treatment for accurate SDT are introduced. Further, an overview of the development of sonosensitizers is provided from small molecular sensitizers to nano/microenhanced sensitizers. Several types of nanomaterial-augmented SDT are in discussion, including porphyrin-based nanomaterials, porphyrin-like nanomaterials, inorganic nanomaterials, and organic-inorganic hybrid nanomaterials with different strategies to improve SDT therapeutic efficacy. There is no doubt that the rapid development and clinical translation of sonodynamic therapy will be promoted by advanced equipment, smart nanomaterial-based sonosensitizer, and multidisciplinary collaboration.

Modulation of the triggered apoptosis by nano emodin transfersome-mediated sonodynamic therapy on head and neck squamous cell carcinoma cell lines

BACKGROUND

Non-invasive sonodynamic therapy (SDT) is a new treatment modality that uses low-intensity ultrasound to activate a non-toxic sensitizing chemical agent for cancer therapy in a site-directed manner. This study aimed to investigate the anti-cancer effects of ultrasound combined with nano emodin transfersome (NET) on head and neck squamous cell carcinoma (HNSCC) cell lines.

MATERIALS AND METHODS

A transfersome form of nano emodin as a novel sono-responsive nanomaterial was synthesized to enhance the accumulation and penetration of nanoparticles. iIn vitro experiments including hemolytic activity, cell proliferation, intracellular reactive oxygen species (ROS) generation, apoptosis induction, DNA fragmentation, and mRNA expressions of caspase 3 and 9 were conducted to explore the anti-cancer effects of NET-SDT on FaDu and CAL-27 cell lines.

RESULTS

Characterization tests showed the round and uniform morphology of NET with transfersome structure, resulting in a high drug-loading content and encapsulation efficiency. No significant hemolytic activity was observed (P > 0.05). Cytotoxicity gradually increased with increasing concentrations of NET, so that 10 × 10^-4 g/L of NET plus 5 min ultrasound irradiation at a frequency of 1 MHz and ultrasonic intensity of 2 W/cm² effectively killed 98.2 % and 97.3 % of FaDu and CAL-27 cell lines, respectively (P < 0.05). We found that ROS generation in NET-SDT was dose-dependent and the triggered apoptosis and caspase-3/9 gene expression levels were significantly enhanced as the concentration of NET increased (P < 0.05). No significant difference was found in the rate of apoptosis induction and gene expression between two cell lines.

CONCLUSIONS

Our data demonstrated that SDT with NET as a sonosensitizer can induce apoptosis and significantly decrease cell viability of HNSCC cell lines, which represents the role of NET-SDT as a potent anti-cancer modality.

K. PK, Lee J, Kim CH, You DG, Park JH. Recent advances in nanomaterial-based augmented sonodynamic therapy of cancer

This review focuses on recent advances in augmented sonodynamic therapy (SDT) using engineered nanomaterials, and the mechanism of SDT for discussing future perspectives.

A Review of Mesoporous Silica Nanoparticle Delivery Systems in Chemo-Based Combination Cancer Therapies

Chemotherapy is an important anti-tumor treatment in clinic to date, however, the effectiveness of traditional chemotherapy is limited by its poor selectivity, high systemic toxicity, and multidrug resistance. In recent years, mesoporous silica nanoparticles (MSNs) have become exciting drug delivery systems (DDS) due to their unique advantages, such as easy large-scale production, adjustable uniform pore size, large surface area and pore volumes. While mesoporous silica-based DDS can improve chemotherapy to a certain extent, when used in combination with other cancer therapies MSN based chemotherapy exhibits a synergistic effect, greatly improving therapeutic outcomes. In this review, we discuss the applications of MSN DDS for a diverse range of chemotherapeutic combination anti-tumor therapies, including phototherapy, gene therapy, immunotherapy and other less common modalities. Furthermore, we focus on the characteristics of each nanomaterial and the synergistic advantages of the combination therapies. Lastly, we examine the challenges and future prospects of MSN based chemotherapeutic combination therapies.

Recent Advances in Nanomaterial-Assisted Combinational Sonodynamic Cancer Therapy

Ultrasound (US)-triggered sonodynamic therapy (SDT), as a promising noninvasive therapeutic modality, has received ever-increasing attention in recent years. Its specialized chemical agents, named sonosensitizers, are activated by low-intensity US to produce lethal reactive oxygen species (ROS) for oncotherapy. Compared with phototherapeutic strategies, SDT provides many noteworthy opportunities and benefits, such as deeper penetration depth, absence of phototoxicity, and fewer side effects. Nevertheless, previous studies have also demonstrated its intrinsic limitations. Thanks to the facile engineering nature of nanotechnology, numerous novel nanoplatforms are being applied in this emerging field to tackle these intrinsic barriers and achieve continuous innovations. In particular, the combination of SDT with other treatment strategies has demonstrated a superior efficacy in improving anticancer activity relative to that of monotherapies alone. Therefore, it is necessary to summarize the nanomaterial-assisted combinational sonodynamic cancer therapy applications. Herein, the design principles in achieving synergistic therapeutic effects based on nanomaterial engineering methods are highlighted. The ultimate goals are to stimulate the design of better-quality combined sonodynamic treatment schemes and provide innovative ideas for the perspectives of SDT in promoting its future transformation to clinical application.

Exploiting Lipid and Polymer Nanocarriers to Improve the Anticancer Sonodynamic Activity of Chlorophyll

Sonodynamic therapy is an emerging approach that uses low-intensity ultrasound to activate a sonosensitizer agent triggering its cytotoxicity for selective cancer cell killing. Several molecules have been proposed as sonosensitizer agents, but most of these, as chlorophyll, are strongly hydrophobic with a low selectivity towards cancer tissues. Nanocarriers can help to deliver more efficiently the sonosensitizer agents in the target tumor site, increasing at the same time their sonodynamic effect, since nanosystems act as cavitation nuclei. Herein, we propose the incorporation of unmodified plant-extracted chlorophyll into nanocarriers with different composition and structure (i.e., liposomes, solid lipid nanoparticles and poly(lactic-co-glycolic acid) nanoparticles) to obtain aqueous formulations of this natural pigment. The nanocarriers have been deeply characterized and then incubated with human prostatic cancer cells (PC-3) and spheroids (DU-145) to assess the influence of the different formulations on the chlorophyll sonodynamic effect. The highest sonodynamic cytotoxicity was obtained with chlorophyll loaded into poly(lactic-co-glycolic acid) nanoparticles, showing promising results for future clinical investigations on sonodynamic therapy.

Photo- and Sono-Dynamic Therapy: A Review of Mechanisms and Considerations for Pharmacological Agents Used in Therapy Incorporating Light and Sound

As irreplaceable energy sources of minimally invasive treatment, light and sound have, separately, laid solid foundations in their clinic applications. Constrained by the relatively shallow penetration depth of light, photodynamic therapy (PDT) typically involves involves superficial targets such as shallow seated skin conditions, head and neck cancers, eye disorders, early-stage cancer of esophagus, etc. For ultrasound-driven sonodynamic therapy (SDT), however, to various organs is facilitated by the superior... transmission and focusing ability of ultrasound in biological tissues, enabling multiple therapeutic applications including treating glioma, breast cancer, hematologic tumor and opening blood-brain-barrier (BBB). Considering the emergence of theranostics and precision therapy, these two classic energy sources and corresponding sensitizers are worth reevaluating. In this review, three typical therapies using light and sound as a trigger, PDT, SDT, and combined PDT and SDT are introduced. The therapeutic dynamics and current designs of pharmacological sensitizers involved in these therapies are presented. By introducing both the history of the field and the most up-to-date design strategies, this review provides a systemic summary on the development of PDT and SDT and fosters inspiration for researchers working on 'multi-modal' therapies involving light and sound.

Sinoporphyrin sodium based sonodynamic therapy induces anti-tumor effects in hepatocellular carcinoma and activates p53/caspase 3 axis

Sonodynamic therapy (SDT) is a noninvasive therapeutic method via the activation of certain chemical sensitizers using low intensity ultrasound. In this work, we evaluated the antitumor effect of sinoporphyrin sodium (DVDMS) mediated SDT (DVDMS-SDT) on Hepatocellular carcinoma (HCC) cell lines both in vitro and in vivo. The results indicated that DVDMS-SDT was significantly more efficacious than PpIX-SDT in treating hepatocellular cell line Hep-G2. DVDMS-SDT also increased the ratio of cells in the G2/M phase and decreased the CDK1 and Cyclin B1 protein level. DVDMS-SDT markedly increased intracellular reactive oxygen species (ROS) in vitro. The increased ROS production up-regulated the expression of p53 and Bax, and down-regulated Bcl-2 expression, which led to the activation of caspase-3, ultimately initiated cell apoptosis. These effects could be partially reversed by the ROS scavenger N-acetylcysteine (NAC). In vivo experiments revealed that the DVDMS-SDT resulted in an effective inhibition of tumor growth and prolonged the survival time of tumor-bearing mice. More importantly, no obvious signs of side effects were observed. These results suggested that DVDMS-SDT is very effective in treating Hepatocellular carcinoma without side effects. The primary mechanism of SDT is due to the increased ROS activated the p53/Caspase 3 axis of apoptosis.

Blocking the Glycolytic Pathway Sensitizes Breast Cancer to Sonodynamic Therapy

Inhibition of the increased aerobic glycolysis in cancer cells is a promising methodology for various malignant tumor therapies but is limited by systemic toxicity, at least in part. Recent studies suggest that dual restriction of glycolysis and mitochondrial function may overcome this issue. Sonodynamic therapy (SDT), a prospective therapeutic modality for cancers, has been reported to induce mitochondria-dependent cell damage. Here, we investigated the combined effect of SDT and 2-deoxyglucose (2DG), an anti-glycolytic agent, on breast cancer both in vitro and in vivo. In vitro, we found that, compared with a single treatment, SDT + 2DG co-treatment significantly decreased cell viability and increased cell apoptosis. Moreover, the generation of reactive oxygen species was enhanced and mitochondrial membrane potential (MMP) was reduced after SDT + 2DG co-treatment. Furthermore, the oxidative phosphorylation was also restrained after SDT + 2DG co-treatment, further to cause the blockage of ATP provision. In vivo, SDT + 2DG markedly reduced tumor volume and weight, consistent with the in vitro findings. Furthermore, toxicology tests concurrently indicated that the dosages of sinoporphyrin sodium and 2DG were comparatively tolerable. Generally, these results indicated that SDT + 2DG combination therapy may be an available, promising therapy for highly metastatic breast cancer.

Sonodynamic therapy (SDT): a novel strategy for cancer nanotheranostics

Sonodynamic therapy (SDT) is a promising non-invasive therapeutic modality. Compared to photo-inspired therapy, SDT provides many opportunities and benefits, including deeper tissue penetration, high precision, less side effects, and good patient compliance. Thanks to the facile engineerable nature of nanotechnology, nanoparticles-based sonosensitizers exhibit predominant advantages, such as increased SDT efficacy, binding avidity, and targeting specificity. This review aims to summarize the possible mechanisms of SDT, which can be expected to provide the theoretical basis for SDT development in the future. We also extensively discuss nanoparticle-assisted sonosensitizers to enhance the outcome of SDT. Additionally, we focus on the potential strategy of combinational SDT with other therapeutic modalities and discuss the limitations and challenges of SDT toward clinical applications.

Micro/Nanoparticle-Augmented Sonodynamic Therapy (SDT): Breaking the Depth Shallow of Photoactivation

The fast development of photoactivation for cancer treatment provides an efficient photo-therapeutic strategy for cancer treatment, but traditional photodynamic or photothermal therapy suffers from the critical issue of low in vivo penetration depth of tissues. As a non-invasive therapeutic modality, sonodynamic therapy (SDT) can break the depth barrier of photoactivation because ultrasound has an intrinsically high tissue-penetration performance. Micro/nanoparticles can efficiently augment the SDT efficiency based on nanobiotechnology. The state-of-art of the representative achievements on micro/nanoparticle-enhanced SDT is summarized, and specific functions of micro/nanoparticles for SDT are discussed, from the different viewpoints of ultrasound medicine, material science and nanobiotechnology. Emphasis is put on the relationship of structure/composition-SDT performance of micro/nanoparticle-based sonosensitizers. Three types of micro/nanoparticle-augmented SDT are discussed, including organic and inorganic sonosensitizers and micro/nanoparticle-based but sonosensitizer-free strategies to enhance the SDT outcome. SDT-based synergistic cancer therapy augmented by micro/nanoparticles and their biosafety are also included. Some urgent critical issues and potential developments of micro/nanoparticle-augmented SDT for efficient cancer treatment are addressed. It is highly expected that micro/nanoparticle-augmented SDT will be quickly developed as a new and efficient therapeutic modality which will find practical applications in cancer treatment. At the same time, fundamental disciplines regarding materials science, chemistry, medicine and nanotechnology will be advanced.

Enhancement of anti-tumor effects of 5-fluorouracil on hepatocellular carcinoma by low-intensity ultrasound

Background

Hepatocellular carcinoma (HCC) accounts for 75 % of liver cancers and is the second most lethal cancer, associated with its multiple etiologies, poor prognosis and resistance to chemotherapy drugs. Chemotherapy treatment on HCC suffers low efficacy of drug uptake and can produce a range of side effects. Here we report an investigation on the effect of a combined treatment on human hepatocellular carcinoma BEL-7402 cells using low-intensity ultrasound (US) and 5-fluorouracil (5-FU).

Methods

The uptake of 5-FU was measured by the high-performance liquid chromatography (HPLC). DNA damage was detected by the comet assay. MTT assay was used to examine cell viability. Intracellular reactive oxygen species (ROS) and mitochondrial membrane potential (Δψm) were respectively detected by the fluorescent probes DCFH-DA or JC-1. Endogenous apoptosis-associated proteins were analyzed by the western blot and immunohistochemistry. Histopathological changes were evaluated by the hematoxylin and eosin (H&E) staining. Cell apoptosis was evaluated by the TUNEL and flow cytometry assays. Cell proliferation was measured using the immunohistochemical staining of PCNA.

Results

Our results showed that low-intensity US (1.1 MHz, 1.0 W/cm², 10 % duty cycle) significantly enhanced the uptake of 5-FU, 5-FU-mediated DNA damage and reactive oxygen species (ROS) generation. The increased ROS production up-regulated the p53 protein level, which led to the up-regulation of Bax and down-regulation of Bcl-2. The enhancement of ROS generation and the activation of the apoptosis-associated proteins further triggered the collapse of mitochondrial membrane potential, released cytochrome c from mitochondria into cytosol and activated the mitochondria-caspase pathway, and cell apoptosis. Such enhanced effects could be partially blocked by the ROS scavenger N-acetylcysteine (NAC). Overall, low-intensity US combined with 5-FU led to an effective inhibition of tumor growth and prolonged overall survival of BEL-7402 HCC-bearing nude mice by more than 15 % compared with 5-FU treatment alone.

Conclusions

Our results showed that low-intensity ultrasound combined with 5-FU produced much enhanced synergistic anti-tumor effects via enhanced ROS production in treating HCC.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0349-4) contains supplementary material, which is available to authorized users.

Microbubbles Enhance the Antitumor Effects of Sinoporphyrin Sodium Mediated Sonodynamic Therapy both In Vitro and In Vivo

Objectives: To evaluate the anti-cancer effect of sonodynamic therapy combined with microbubbles both in vitro and in vivo.

Methods: Cell viability was measured by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide and guava viacount assays. Annexin V-FITC/PI staining was adopted to analyze cell apoptosis rate. FD500 uptake assay was performed to assess cell membrane permeability changes. Tumor weight, mice weight and the visual image of tumor size were used to reflect the anti-tumor effect of this combined method. Histological change of tumor tissue after different treatments was measured through hematoxylin and eosin (H&E) staining.

Results: Microbubbles can significantly enhance the cytotoxicity and necrocytosis rate induced by SDT treatment. Increased cell membrane permeability and more uptake of DVDMS were founded in SDT combined with microbubbles group. For in vivo experiments, SDT with microbubbles can significantly reduce tumor weight and size with pimping difference of mice weight compare with other treatment groups. In addition, microbubbles notably improved tumor tissue destruction caused by ultrasound and SDT treatment.

Conclusion: The results suggest that microbubbles can markedly improve the anti-cancer effect of DVDMS mediate sonodynamic therapy both in vitro and in vivo.

The decomposition of protoporphyrin IX by ultrasound is dependent on the generation of hydroxyl radicals

The ultrasound activation of certain drugs, such as porphyrins, could cause synergistic cytotoxic effects on cells. Both sonomechanical and sonochemical effects occur and the latter play a critical role because antioxidant agents could exert significant protective effects against the cytotoxicity. To investigate the reactive oxygen species involved in the sonochemical effects, aqueous protoporphyrin IX (PpIX) solutions were characterized under ultrasound sonication in this study. Inertial cavitation was indirectly evaluated using terephthalic acid dosimetry. The fluorescence intensity of the PpIX was measured using a fluorescence spectrophotometer. The effects of PpIX concentration, ultrasound parameters and free radical scavengers on the PpIX activation by ultrasound were investigated. Our results showed that the increase in PpIX decomposition was significantly correlated with cavitation activities (R=0.9874, p<0.05), and the decomposing effect increases with ultrasound intensity (0.6-1.5 W/cm(2)), initial PpIX concentration (1-5 μM), duty cycle (10-100%) and the sonication duration (2-10 min). The fluorescence and absorption spectra of PpIX showed a decrease in the peak intensity without spectral shifts or new peak build-up after sonication. The PpIX decomposition was significantly inhibited by hydroxyl radical scavengers, histidine, mannitol, acetone, methanol and ethanol, but the decomposition was not inhibited by sodium azide, catalase or superoxide dismutase. These results suggest that the decomposition of protoporphyrin IX by ultrasound is dependent on the generation of hydroxyl radicals, which sheds some light on the sonochemical effects of the interaction between ultrasound and porphyrins.

Porphyrin derivatives-mediated sonodynamic therapy for malignant gliomas in vitro

Because it is highly infiltrative, malignant glioma is a cancer with a poor prognosis despite multidisciplinary treatment strategies, such as aggressive surgery and chemoradiotherapy, necessitating new therapeutic approaches to control migration of tumor cells. In our study, we investigated the efficacy of sonodynamic therapy of glioma cells in vitro using porphyrin derivatives, including 5-aminolevulinic acid, protoporphyrin IX and talaporfin sodium, as sonosensitizers. These substances have been known to accumulate in glioma cells and are expected to have cytotoxic effects on sonication. Our study found that the cytotoxicity of sonication of glioma cells is enhanced by each sonosensitizer and that the efficacy of sonodynamic therapy may depend on the degree of intracellular accumulation of sonosensitizer. Also, the study suggests that induction of apoptosis is a major mechanism underlying cell death. Though further investigations are necessary, our preliminary result indicates a potential for sonodynamic therapy with sonosensitizers in glioma treatment.

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.

Apoptosis induced by sonodynamic therapy in human osteosarcoma cells in vitro

The aim of the present study was to investigate the potential effect of hematoporphyrin monomethyl ether-sonodynamic therapy (HMME-SDT) on MG-63 osteosarcoma cells. The HMME concentration was kept constant at 20 µg/ml and the MG-63 osteosarcoma cell line was exposed to ultrasound with an intensity of 1.0 W/cm2 for 30 sec. Cell cytotoxicity was quantified using an MTT assay 6 h after HMME-SDT. The intracellular localization of HMME was imaged using inverted confocal laser scanning microscopy. Apoptosis was investigated using flow cytometry with Annexin V-fluorescein isothiocyanate and propidium iodine staining. The cytotoxicity of HMME-mediated sonodynamic action on MG-63 cells was significantly higher than that of other treatments, including ultrasound alone, HMME alone and sham treatment. Flow cytometry demonstrated that HMME‑SDT action markedly enhanced the apoptotic rate of MG-63 cells. The mechanisms of apoptosis were analyzed by measuring the protein expression of poly ADP-ribose polymerase (PARP), cleaved PARP, procaspase-3, cleaved caspase-3 and cleaved caspase-9. The data demonstrated that HMME-SDT action markedly induced the apoptosis of MG-63 cells.

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.

Involvement of mitochondrial and reactive oxygen species in the sonodynamic toxicity of chlorin e6 in human leukemia K562 cells

It is well accepted that sonodynamic therapy (SDT) exerts cytotoxicity and anti-tumor activity in many human tumors through the induction of cell apoptosis. The aim of the work described here was to study the effect of chlorin e6 (Ce6)-mediated SDT on human chronic myelogenous leukemia K562 cells. Our results indicate that Ce6-mediated SDT can suppress the viability of K562 cells. SDT caused apoptosis as analyzed by annexin V-phycoerythrin/7-amino-actinomycin D staining as well as cleavage of caspase 3 and the polypeptide poly(ADP-ribose) polymerase. After SDT exposure, loss of mitochondrial membrane potential, translocation of Bax from cytoplasm to mitochondria and activation of caspase 9 indicated that the mitochondrial-related apoptotic pathway might be activated. This process was accompanied by rapid generation of reactive oxygen species (ROS). Scavenging of ROS significantly blocked caspase-3 expression and the killing effect of SDT on K562 cells. Stress-activated protein kinases c-jun NH2-terminal kinase (JNK) and the p38 mitogen-activated protein kinase were activated after SDT treatment. Together, these findings indicate that Ce6-mediated SDT triggers mitochondria- and caspase-dependent apoptosis; oxidative injury may play a vital role in apoptotic signaling cascades.

Apoptosis of THP-1 derived macrophages induced by sonodynamic therapy using a new sonosensitizer hydroxyl acetylated curcumin

Curcumin is extracted from the rhizomes of the traditional Chinese herb Curcuma longa. Our previous study indicated curcumin was able to function as a sonosensitizer. Hydroxyl acylated curcumin was synthesized from curcumin to eliminate the unstable hydroxy perssad in our group. The potential use of Hydroxyl acylated curcumin as a sonosensitizer for sonodynamic therapy (SDT) requires further exploration. This study investigated the sonodynamic effect of Hydroxyl acylated curcumin on THP-1 macrophage. THP-1 macrophages were cultured with Hydroxyl acylated curcumin at a concentration of 5.0 μg/mL for 4 hours and then exposed to pulse ultrasound irradiation (0.5 W/cm² with 1.0 MHz ) for 5 min, 10 min and 15 min. Six hours later, cell viability decreased significantly by CCK-8 assay. After ultrasound irradiation, the ratio of apoptosis and necrosis in SDT group was higher than that in control, Hydroxyl acylated curcumin alone and ultrasound alone. Moreover, the apoptotic rate was higher than necrotic rate with the flow cytometry analysis. Furthermore, Hydroxyl acylated curcumin-SDT induced reactive oxygen species (ROS) generation in THP-1 macrophages immediately after the ultrasound treatment while ROS generation was reduced significantly with the scavenger of singlet oxygen Sodium azide (NaN₃). Hydroxyl acylated curcumin-SDT led to a conspicuous loss of mitochondrial membrane potential (MMP) compared with other groups, while MMP was increased significantly with the scavenger of singlet oxygen Sodium azide (NaN₃), ROS inhibitor N-acetyl cysteine (NAC) and Mitochondrial Permeability Transition Pore (MPTP) inhibitor Cyclosporin A (CsA). The cytochrome C, cleaved-Caspase-9, cleaved-Caspase-3 and cleaved-PARP upregulated after SDT through Western blotting. These findings suggested that Hydroxyl acylated curcumin under low-intensity ultrasound had sonodynamic effect on THP-1 macrophages via generation of intracellular singlet oxygen and mitochondria-caspase signaling pathway, indicating that Hydroxyl acylated curcumin could be used as a novel sonosensitizer in SDT for atherosclerosis.

Apoptosis of U937 cells induced by hematoporphyrin monomethyl ether-mediated sonodynamic action

PURPOSE

The present study aims to investigate apoptosis of U937 cells induced by hematoporphyrin monomethyl ether (HMME)-mediated sonodynamic therapy (SDT).

MATERIALS

HMME concentration was kept constant at 10 μg/mL. Tumor cells suspended in serum-free RPM1640 were exposed to ultrasound at 1.1 MHz for up to 60 seconds with an intensity of 1 W/cm(2) in the presence and absence of HMME. The viability of cells was determined by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltertrazolium bromide tetrazolium (MTT) test. Apoptosis was analyzed using a flow cytometer with Annexin V-PE/7-ADD staining as well as fluorescence microscopy with 4'-6-diamidino-2-phenylindole (DAPI) staining. The DNA damage of U937 cells, intracellular reactive oxygen species (ROS), and mitochondria membrane potential (MMP) were also analyzed by a flow cytometer after exposures. Western blotting and reverse transcriptase-polymerase chain reaction were used to analyze the protein and mRNA expression level of caspase-3 and poly(ADP-ribose) polymerase (PARP).

RESULTS

Fluorescent imaging revealed that HMME mainly localized in the mitochondria. MTT assay showed 55.6% of cell survival at 4 hours post-SDT. Flow cytometric analysis displayed a significant increase in the early- and late-apoptotic cell populations (35.6%) of U937 cells by HMME-mediated SDT. Compared with the control, ultrasound-alone, and HMME-alone groups, the intracellular ROS and the MMP loss were greatly increased in the combined SDT group. Obvious nuclear condensation was also found with DAPI staining, and the DNA fragment increased to 33.9% at 2 hours post-SDT treatment. Immunofluorescent staining indicated obvious Bax translocation after SDT. Western blot showed visible enhancement of caspase-3 and PARP cleavage. In addition, caspase-3 and PARP mRNA expression of U937 cells increased remarkably after SDT treatment.

CONCLUSIONS

The findings demonstrated that HMME-mediated sonodynamic action (HMME-SDT) significantly induced apoptosis of U937 cells, suggesting that HMME may be a good sonosensitizer, and HMME-SDT might be a potential therapeutic strategy for cancer treatment.

The induction of the apoptosis of cancer cell by sonodynamic therapy: a review

Ultrasound can be used not only in the examination, but also in the therapy, especially in the therapy of cancer, which has got effect in the treatment. Sonodynamic therapy is an experimental cancer therapy which uses ultrasound to enhance the cytotoxic effects of drugs known as sonosensitizers. It has been tested in vitro and in vivo. The ultrasound could penetrate the tissue and cell under some of conditions which directly changes the cell membranes permeability, thereby allowing the delivery of exogenous molecules into the cells in some degree. Ultrasound could inhibit the proliferation or induce the apoptosis of the cancer cell in vitro or in vivo. Recent research indicated low frequency and low intensity ultrasound could induce cells apoptosis, and which could be strengthened by sonodynamic sensitivities, microbubbles, chemotherapeutic drugs and so on. Most kinds of ultrasound suppressed the proliferation of cancer cell through inducing the apoptosis of cancer cell. The mechanism of apoptosis is not clear. In this review, we will focus on and discuss the mechanisms of the induction of the apoptosis of cancer cell by ultrasound.

The ABCG2 transporter is a key molecular determinant of the efficacy of sonodynamic therapy with Photofrin in glioma stem-like cells

We aimed to investigate the role of the ABCG2 transporter in the efficacy of sonodynamic therapy (SDT) with Photofrin in the glioma stem-like cells (GSCs) isolated and cultured from U251 glioma cells. Immunocytochemistry and flow cytometry analyses showed that ABCG2 was overexpressed in GSCs, and the percentage of ABCG2-positive GSCs was approximately 100%. The effect of ABCG2 on Photofrin extrusion in the absence or presence of a specific inhibitor of ABCG2 (fumitremorgin C; FTC) was investigated by determining the intracellular concentration of Photofrin in GSCs incubated with 20μg/ml Photofrin. Extrusion of Photofrin by ABCG2 was inhibited by 10μM FTC, which significantly increased the intracellular Photofrin concentration (p<0.05) from 0.32±0.11μg/10(6) cells to 0.89±0.13μg/10(6) cells. MTT and TUNEL assays showed that the antitumor effect of SDT (incubation of GSCs with 20μg/ml Photofrin for 6h in the dark and ultrasonic activation at 1.0MHz and 0.5W/cm(2) for 2min) was significantly improved by FTC pretreatment (p<0.05). Moreover, incubation of GSCs with FTC significantly increased the relative production of ROS in response to SDT. The overexpression of ABCG2 in GSCs results in efflux of Photofrin, indicating that the antitumor effect of SDT with Photofrin may be reduced in GSCs overexpressing ABCG2. However, since FTC improves the efficacy of SDT in GSCs by inhibiting ABCG2-mediated efflux of Photofrin, FTC may be useful in SDT treatment of ABCG2-expressing cancer cells.

Involvement of reactive oxygen species in sonodynamically induced apoptosis using a novel porphyrin derivative

In this study, we investigated the induction of apoptosis by ultrasound in the presence of the novel porphyrin derivative DCPH-P-Na(I). HL-60 cells were exposed to ultrasound for up to 3 min in the presence and absence of DCPH-P-Na(I), and the induction of apoptosis was examined by analyzing cell morphology, DNA fragmentation, and caspase-3 activity. Reactive oxygen species were measured by means of ESR and spin trapping technique. Cells treated with 8 μM DCPH-P-Na(I) and ultrasound clearly showed membrane blebbing and cell shrinkage, whereas significant morphologic changes were not observed in cells exposed to either ultrasound or DCPH-P-Na(I) alone. Also, DNA ladder formation and caspase-3 activation were observed in cells treated with both ultrasound and DCPH-P-Na(I) but not in cells treated with ultrasound or DCPH-P-Na(I) alone. In addition, the combination of DCPH-P-Na(I) and the same acoustical arrangement of ultrasound substantially enhanced nitroxide generation by the cells. Sonodynamically induced apoptosis, caspase-3 activation, and nitroxide generation were significantly suppressed by histidine. These results indicate that the combination of ultrasound and DCPH-P-Na(I) induced apoptosis in HL-60 cells. The significant reduction in sonodynamically induced apoptosis, nitroxide generation, and caspase-3 activation by histidine suggests active species such as singlet oxygen are important in the sonodynamic induction of apoptosis. These experimental results support the possibility of sonodynamic treatment for cancer using the induction of apoptosis.

Phase-shift, stimuli-responsive drug carriers for targeted delivery

The intersection of particles and directed energy is a rich source of novel and useful technology that is only recently being realized for medicine. One of the most promising applications is directed drug delivery. This review focuses on phase-shift nanoparticles (that is, particles of submicron size) as well as micron-scale particles whose action depends on an external-energy triggered, first-order phase shift from a liquid to gas state of either the particle itself or of the surrounding medium. These particles have tremendous potential for actively disrupting their environment for altering transport properties and unloading drugs. This review covers in detail ultrasound and laser-activated phase-shift nano- and micro-particles and their use in drug delivery. Phase-shift based drug-delivery mechanisms and competing technologies are discussed.

Hypocrellin B-mediated sonodynamic action induces apoptosis of hepatocellular carcinoma cells

OBJECTIVE

The present study aims to investigate apoptosis of hepatocellular carcinoma cells induced by hypocrellin B-mediated sonodynamic action.

METHODS

The hypocrellin B concentration was kept constant at 2.5 μM and cells from the hepatocellular carcinoma HepG2 cell line were exposed to ultrasound with an intensity of 0.46 W/cm(2) for 8s. Cell cytotoxicity was quantified using an MTT assay 24 h after sonodynamic therapy (SDT) of hypocrellin B. Apoptosis was investigated using a flow cytometry with Annexin V-FITC and propidium iodine staining. Intracellular reactive oxygen species (ROS) levels were detected using a flow cytometry with 2,7-dichlorodihydrofluorecein diacetate (DCFH-DA) staining.

RESULTS

The cytotoxicity of hypocrellin B-mediated sonodynamic action on HepG2 cells was significantly higher than those of other treatments including ultrasound alone, hypocrellin B alone and sham treatment. Flow cytometry showed that hypocrellin B-induced sonodynamic action markedly enhanced the apoptotic rate of HepG2 cells. Increased ROS was observed in HepG2 cells after being treated with hypocrellin B-mediated sonodynamic action.

CONCLUSIONS

Our data demonstrated that hypocrellin B-mediated sonodynamic action remarkably induced apoptosis of HepG2 cells, suggesting that apoptosis is an important mechanism of cell death induced by hypocrellin B-mediated SDT.

Calcium overload induces C6 rat glioma cell apoptosis in sonodynamic therapy

PURPOSE

Our aim was to study calcium overload-induced apoptosis and its relation to reactive oxygen species (ROS) in rat C6 glioma cells after sonodynamic treatment (SDT).

MATERIALS AND METHODS

Hematoporphyrin monomethyl ether (HMME) was used as the sonosensitizer. The concentration of intracellular Ca(2+) ([Ca(2+)](i)) was measured by fluorometry. Apoptosis and necrosis rates were evaluated by a flow cytometry. Moreover, sarcoplasmic reticulum Ca(2+) -ATPase (SERCA(2)), cytochrome c (cyto-c) and cleaved caspase-3 were investigated by immunoblotting.

RESULTS

Our study indicated that [Ca(2 +)](i) and ROS increased in cells of SDT group, the apoptosis rate, quantity of cyto-c and cleaved caspase-3 markedly increased after SDT. Furthermore, N-Acetyl-L-cysteine (NAC) or 1,2-bisethane-N,N,N',N'-tetraacetic acid tetrakis ester (BAPTA-AM) could decrease the apoptosis rate, the release of cyto-c and cleaved caspase-3 in SDT group, SERCA(2) degradation was found in SDT group and could also be prevented by the addition of NAC.

CONCLUSIONS

Our results show that HMME-SDT can induce C6 cell death through both necrosis and apoptosis. ROS in C6 cells play a decisive role in HMME-SDT-induced cell death. The endoplasmic reticulum (ER) may be a major target of HMME-SDT, ROS can induce SERCA(2) degradation, causing the elevation of [Ca(2+)](i).

Sonodynamically induced anti-tumor effect with protoporphyrin IX on hepatoma-22 solid tumor

OBJECTIVE

The purpose of this study was to evaluate sonodynamically induced anti-tumor effect of protoporphyrin IX (PPIX) in mice bearing hepatoma-22 (H-22) solid tumors, and the possible in vivo cell damage mechanism was also investigated.

METHODS

The pharmacokinetics of PPIX was analyzed in plasma, skin, muscle and tumor of H-22 bearing mice. Tumors were irradiated with ultrasound (1.43MHz, I(SATA) 3W/cm(2), 3min) for three times at 8, 12 and 24h after 5.0mg/kg PPIX administration, respectively. The anti-tumor effects of sonodynamic therapy (SDT) were estimated by the tumor inhibition ratio (volume and weight). The bio-effects of SDT were evaluated by hematoxylin and eosin (H&E) staining, transmission electron microscope (TEM) observation, lipid peroxidation (LPO) measurement and anti-oxidative enzymes (glutathione peroxidase (GSH-PX), catalase (CAT) and superoxide dismutase (SOD)) assay.

RESULTS

A significant anti-tumor effect was obtained by PPIX-mediated sonodynamic therapy (PPIX-SDT). At the fifteenth day after PPIX-SDT, the tumor growth and tumor weight inhibition ratios were 53.84% and 45.86%, respectively. In addition, the structure of tumor tissues and the anti-oxidative enzymes were obviously destroyed after SDT treatment.

CONCLUSIONS

A biochemical mechanism was involved in PPIX-SDT in vivo, and the free radicals produced by the synergistic treatment destroying the anti-oxidative system of tumor cells in vivo may play an important role in this action. Also, the thermal effect could not be excluded in inducing damage of cellular structures, like membrane disruption and chromatin condensation under current evaluation in this paper.

Apoptosis of ovarian cancer cells induced by methylene blue-mediated sonodynamic action

OBJECTIVE

The present study aims to investigate apoptosis of ovarian cancer cells induced by methylene blue (MB)-mediated sonodynamic therapy (SDT).

METHODS

The MB concentration was kept constant at 100μM and ovarian cancer HO-8910 cells were exposed to ultrasound therapy for 5s with an intensity of 0.46W/cm(2). The cytotoxicity was investigated 24h after MB-mediated sonodynamic action. Apoptosis was analyzed using a flow cytometer with Annexin V-FITC and propidium iodine (PI) staining as well as fluorescence microscopy with Hoechst 33258 staining. Intracellular reactive oxygen species (ROS) level was measured by flow cytometer with 2,7-dichlorodihydrofluorescein diacetate (DCFH-DA) staining.

RESULTS

The cytotoxicity of MB-mediated SDT on HO-8910 cells after MB-mediated SDT was significantly higher than those of other treatments including ultrasound alone, MB alone and sham treatment. Flow cytometric analysis showed a significant increase in the early and late apoptotic cell populations by MB-mediated SDT of HO-8910 cells. Nuclear condensation and increased ROS levels were also found in HO-8910 cells treated by MB-mediated SDT.

CONCLUSIONS

Our findings demonstrated that MB-mediated sonodynamic action significantly induced apoptosis of HO-8910 cells and an increase in intracellular ROS level. This indicates that apoptosis is an important mechanism of cell death induced by MB-mediated SDT. Thus, MB-mediated SDT might be a potential therapeutic strategy for combating ovarian cancer.