5-Aminolevulinic Acid-Based Sonodynamic Therapy Induces the Apoptosis of Osteosarcoma in Mice

The abscopal effects of sonodynamic therapy in cancer

The abscopal effect is a phenomenon wherein localised therapy on the primary tumour leads to regression of distal metastatic growths. Interestingly, various pre-clinical studies utilising sonodynamic therapy (SDT) have reported significant abscopal effects, however, the mechanism remains largely enigmatic. SDT is an emerging non-invasive cancer treatment that uses focussed ultrasound (FUS) and a sonosensitiser to induce tumour cell death. To expand our understanding of abscopal effects of SDT, we have summarised the preclinical studies that have found SDT-induced abscopal responses across various cancer models, using diverse combination strategies with nanomaterials, microbubbles, chemotherapy, and immune checkpoint inhibitors. Additionally, we shed light on the molecular and immunological mechanisms underpinning SDT-induced primary and metastatic tumour cell death, as well as the role and efficacy of different sonosensitisers. Notably, the observed abscopal effects underscore the need for continued investigation into the SDT-induced 'vaccine-effect' as a potential strategy for enhancing systemic anti-tumour immunity and combating metastatic disease. The results of the first SDT human clinical trials are much awaited and are hoped to enable the further evaluation of the safety and efficacy of SDT, paving the way for future studies specifically designed to explore the potential of translating SDT-induced abscopal effects into clinical reality.

Ultrasound-augmented cancer immunotherapy

Cancer is a growing worldwide health problem with the most broadly studied treatments, in which immunotherapy has made notable advancements in recent years. However, innumerable patients have presented a poor response to immunotherapy and simultaneously experienced immune-related adverse events, with failed therapeutic results and increased mortality rates. Consequently, it is crucial to develop alternate tactics to boost therapeutic effects without producing negative side effects. Ultrasound is considered to possess significant therapeutic potential in the antitumor field because of its inherent characteristics, including cavitation, pyrolysis, and sonoporation. Herein, this timely review presents the comprehensive and systematic research progress of ultrasound-enhanced cancer immunotherapy, focusing on the various ultrasound-related mechanisms and strategies. Moreover, this review summarizes the design and application of current sonosensitizers based on sonodynamic therapy, with an attempt to provide guidance on new directions for future cancer therapy.

Functional anti-bone tumor biomaterial scaffold: construction and application

Bone tumors, including primary bone tumors and bone metastases, have been plagued by poor prognosis for decades. Although most tumor tissue is removed, clinicians are still confronted with the dilemma of eliminating residual cancer cells and regenerating defective bone tissue after surgery. Therefore, functional biomaterial scaffolds are considered to be the ideal candidates to bridge defective tissues and restrain cancer recurrence. Through functionalized structural modifications or coupled therapeutic agents, they provide sufficient mechanical strength and osteoinductive effects while eliminating cancer cells. Numerous novel approaches such as photodynamic, photothermal, drug-conjugated, and immune adjuvant-assisted therapies have exhibited remarkable efficacy against tumors while exhibiting low immunogenicity. This review summarizes the progress of research on biomaterial scaffolds based on different functionalization strategies in bone tumors. We also discuss the feasibility and advantages of the combined application of multiple functionalization strategies. Finally, potential obstacles to the clinical translation of anti-tumor bone bioscaffolds are highlighted. This review will provide valuable references for future advanced biomaterial scaffold design and clinical bone tumor therapy.

Mitochondria-targeted organic sonodynamic therapy agents: concept, benefits, and future directions

Sonodynamic therapy (SDT) is an emerging and potentially less invasive therapeutic approach for cancer that employs ultrasound (US)-sensitive agents combined with US irradiation to generate cytotoxic reactive oxygen species (ROS) in deep tumor regions. Among various cellular organelles, the mitochondria are particularly susceptible to ROS, making them an attractive target for SDT. Organic-based SDT agents with mitochondria-targeting affinity have gained considerable interest as potential alternatives to conventional SDT agents, offering significant advantages in the field of SDT. However, to date, a comprehensive review focusing on mitochondria-targeted SDT agents has not yet been published. In this review, we provide an overview of the general concept, importance, benefits, and limitations of mitochondria-targeted organic SDT agents in comparison to conventional SDT methods. Finally, we discuss the current challenges and future directions for the design and development of efficient SDT agents. By addressing these issues, we aim to stimulate further research and advancements in the field of mitochondria-targeted SDT, ultimately facilitating the translation of these agents into clinical applications.

Silent Death by Sound: C60 Fullerene Sonodynamic Treatment of Cancer Cells

The acoustic pressure waves of ultrasound (US) not only penetrate biological tissues deeper than light, but they also generate light emission, termed sonoluminescence. This promoted the idea of its use as an alternative energy source for photosensitizer excitation. Pristine C₆₀ fullerene (C₆₀), an excellent photosensitizer, was explored in the frame of cancer sonodynamic therapy (SDT). For that purpose, we analyzed C₆₀ effects on human cervix carcinoma HeLa cells in combination with a low-intensity US treatment. The time-dependent accumulation of C₆₀ in HeLa cells reached its maximum at 24 h (800 ± 66 ng/10⁶ cells). Half of extranuclear C₆₀ is localized within mitochondria. The efficiency of the C₆₀ nanostructure's sonoexcitation with 1 MHz US was tested with cell-based assays. A significant proapoptotic sonotoxic effect of C₆₀ was found for HeLa cells. C₆₀'s ability to induce apoptosis of carcinoma cells after sonoexcitation with US provides a promising novel approach for cancer treatment.

Current status and future perspective of sonodynamic therapy for cancer

There is a tremendous need for prevention and effective treatment of cancer due to the associated morbidity and mortality. In this study, we introduce sonodynamic therapy (SDT), which is expected to be a new cancer treatment modality. SDT is a promising option for minimally invasive treatment of solid tumors and comprises three different components: sonosensitizers, ultrasound, and molecular oxygen. These components are harmless individually, but in combination they generate cytotoxic reactive oxygen species (ROS). We will explore the molecular mechanism by which SDT kills cancer cells, the class of sonosensitizers, drug delivery methods, and in vitro and in vivo studies. At the same time, we will highlight clinical applications for cancer treatment. The progress of SDT research suggests that it has the potential to become an advanced field of cancer treatment in clinical application. In this article, we will focus on the mechanism of action of SDT and its application to cancer treatment, and explain key factors to aid in developing strategies for future SDT development.

Applications of Focused Ultrasound for the Treatment of Glioblastoma: A New Frontier

Glioblastoma (GBM) is an aggressive primary astrocytoma associated with short overall survival. Treatment for GBM primarily consists of maximal safe surgical resection, radiation therapy, and chemotherapy using temozolomide. Nonetheless, recurrence and tumor progression is the norm, driven by tumor stem cell activity and a high mutational burden. Focused ultrasound (FUS) has shown promising results in preclinical and clinical trials for treatment of GBM and has received regulatory approval for the treatment of other neoplasms. Here, we review the range of applications for FUS in the treatment of GBM, which depend on parameters, including frequency, power, pulse duration, and duty cycle. Low-intensity FUS can be used to transiently open the blood-brain barrier (BBB), which restricts diffusion of most macromolecules and therapeutic agents into the brain. Under guidance from magnetic resonance imaging, the BBB can be targeted in a precise location to permit diffusion of molecules only at the vicinity of the tumor, preventing side effects to healthy tissue. BBB opening can also be used to improve detection of cell-free tumor DNA with liquid biopsies, allowing non-invasive diagnosis and identification of molecular mutations. High-intensity FUS can cause tumor ablation via a hyperthermic effect. Additionally, FUS can stimulate immunological attack of tumor cells, can activate sonosensitizers to exert cytotoxic effects on tumor tissue, and can sensitize tumors to radiation therapy. Finally, another mechanism under investigation, known as histotripsy, produces tumor ablation via acoustic cavitation rather than thermal effects.

Ultrasound-triggered oxygen-loaded nanodroplets enhance and monitor cerebral damage from sonodynamic therapy

In sonodynamic therapy, cellular toxicity from sonosensitizer drugs, such as 5-aminolevulinic acid hydrochloride (5-ALA), may be triggered with focused ultrasound through the production of reactive oxygen species (ROS). Here we show that by increasing local oxygen during treatment, using oxygen-loaded perfluorocarbon nanodroplets (250 +/- 8 nm), we can increase the damage induced by 5-ALA, and monitor the severity by recording acoustic emissions in the brain. To achieve this, we sonicated the right striatum of 16 healthy rats after an intravenous dose of 5-ALA (200 mg/kg), followed by saline, nanodroplets, or oxygen-loaded nanodroplets. We assessed haemorrhage, edema and cell apoptosis immediately following, 24 hr, and 48 hr after focused ultrasound treatment. The localized volume of damaged tissue was significantly enhanced by the presence of oxygen-loaded nanodroplets, compared to ultrasound with unloaded nanodroplets (3-fold increase), and ultrasound alone (40-fold increase). Sonicating 1 hr following 5-ALA injection was found to be more potent than 2 hr following 5-ALA injection (2-fold increase), and the severity of tissue damage corresponded to the acoustic emissions from droplet vaporization. Enhancing the local damage from 5-ALA with monitored cavitation activity and additional oxygen could have significant implications in the treatment of atherosclerosis and non-invasive ablative surgeries.

Self-Assembling Imageable Silk Hydrogels for the Focal Treatment of Osteosarcoma

Background: The standard treatment for osteosarcoma comprises complete surgical resection and neoadjuvant chemotherapy, which may cause serious side effects and partial or total limb loss. Therefore, to avoid the disadvantages of traditional treatment, we developed self-assembling imageable silk hydrogels for osteosarcoma.

Methods: We analysed whether iodine induced apoptosis in MG-63 and Saos-2 cells by using CCK-8 and flow cytometry assays and transmission electron microscopy. Western blotting was used to analyse the pathway of iodine-induced apoptosis in osteosarcoma cells. PEG400, silk fibroin solution, polyvinylpyrrolidone iodine (PVP-I), and meglumine diatrizoate (MD) were mixed to produce an imageable hydrogel. A nude mouse model of osteosarcoma was established, and the hydrogel was injected locally into the interior of the osteosarcoma with X-ray guidance. The therapeutic effect and biosafety of the hydrogel were evaluated.

Results: Iodine treatment at 18 and 20 µM for 12 h resulted in cell survival rate reduced to 50 ± 2.1% and 50.5 ± 2.7% for MG-63 and Sao-2 cells, respectively (p < 0.01). The proportion of apoptotic cells was significantly higher in the iodine-treatment group than in the control group (p < 0.05), and apoptotic bodies were observed by transmission electron microscopy. Iodine could regulate the death receptor pathway and induce MG-63 and Saos-2 cell apoptosis. The hydrogels were simple to assemble, and gels could be formed within 38 min. A force of less than 50 N was required to inject the gels with a syringe. The hydrogels were readily loaded and led to sustained iodine release over 1 week. The osteosarcoma volume in the PEG-iodine-silk/MD hydrogel group was significantly smaller than that in the other three groups (p < 0.001). Caspase-3 and poly (ADP-ribose) polymerase (PARP) expression levels were significantly higher in the PEG-iodine-silk/MD hydrogel group than in the other three groups (p < 0.001). Haematoxylin and eosin (H&E) staining showed no abnormalities in the heart, liver, spleen, lung, kidney, pancreas or thyroid in any group.

Conclusions: Self-assembling imageable silk hydrogels could be injected locally into osteosarcoma tissues with X-ray assistance. With the advantages of good biosafety, low systemic toxicity and minimal invasiveness, self-assembling imageable silk hydrogels provide a promising approach for improving the locoregional control of osteosarcoma.

Sonodynamic Therapy for the Treatment of Intracranial Gliomas

High-grade gliomas are the most common and aggressive malignant primary brain tumors. Current therapeutic schemes include a combination of surgical resection, radiotherapy and chemotherapy; even if major advances have been achieved in Progression Free Survival and Overall Survival for patients harboring high-grade gliomas, prognosis still remains poor; hence, new therapeutic options for malignant gliomas are currently researched. Sonodynamic Therapy (SDT) has proven to be a promising treatment combining the effects of low-intensity ultrasound waves with various sound-sensitive compounds, whose activation leads to increased immunogenicity of tumor cells, increased apoptotic rates and decreased angiogenetic potential. In addition, this therapeutic technique only exerts its cytotoxic effects on tumor cells, while both ultrasound waves and sensitizing compound are non-toxic per se. This review summarizes the present knowledge regarding mechanisms of action of SDT and currently available sonosensitizers and focuses on the preclinical and clinical studies that have investigated its efficacy on malignant gliomas. To date, preclinical studies implying various sonosensitizers and different treatment protocols all seem to confirm the anti-tumoral properties of SDT, while first clinical trials will soon start recruiting patients. Accordingly, it is crucial to conduct further investigations regarding the clinical applications of SDT as a therapeutic option in the management of intracranial gliomas.

Targeted sonodynamic destruction of glioblastoma cells using antibody-titanium dioxide nanoparticle conjugates

Aim: We present data on sonodynamic therapy (SDT) against glioblastoma cells utilizing titanium dioxide (TiO₂) nanoparticles conjugated to anti-EGFR antibody. Materials & methods: TiO₂ nanoparticles were bound to anti-EGFR antibody to form antibody-nanoparticle conjugates (ANCs), then characterized by x-ray photoelectron spectroscopy and transmission electron microscopy. Cells underwent ultrasound and assessment on viability, reactive oxygen species and apoptosis were performed. Results: X-ray photoelectron spectroscopy analysis revealed the formation of an ANC. Transmission electron microscopy showed internalization of the ANCs by glioblastoma cells. With SDT, cell viabilities were reduced in the presence of ANCs, reactive oxygen species production was formed, but minimal effect on apoptosis was seen. Conclusion: For the first time, an ANC can be used with SDT to kill glioblastoma cells.

Metalloporphyrins in Medicine: From History to Recent Trends

The history of metalloporphyrins dates back more than 200 years ago. Metalloporphyrins are excellent catalysts, capable of forming supramolecular systems, participate in oxygen photosynthesis, transport, and used as contrast agents or superoxide dismutase mimetics. Today, metalloporphyrins represent complexes of conjugated π-electron system and metals from the entire periodic system. However, the effect of these compounds on living systems has not been fully understood, and researchers are exploring the properties of metalloporphyrins thereby extending their further application. This review provides an overview of the variety of metalloporphyrins that are currently used in different medicine fields and how metalloporphyrins became the subject of scientists' interest. Currently, metalloporphyrins utilization has expanded significantly, which gave us an opprotunuty to summarize recent progress in metalloporphyrins derivatives and prospects of their application in the treatment and diagnosis of different diseases.

An in vitro study on sonodynamic treatment of human colon cancer cells using sinoporphyrin sodium as sonosensitizer

BACKGROUND

Colorectal cancer is the third leading cause of cancer-related deaths worldwide. Sonodynamic therapy (SDT) is an emerging cancer therapy, and in contrast to photodynamic therapy, could non-invasively reach deep-seated tissues and locally activates a sonosensitizer preferentially accumulated in the tumor area to produce cytotoxicity effects. In comparison with traditional treatments, SDT may serve as an alternative strategy for human colon cancer treatment. Here, we investigated the sonodynamic effect using sinoporphyrin sodium (DVDMS) as a novel sonosensitizer on human colon cancer cells in vitro.

RESULTS

The absorption spectra of DVDMS revealed maximum absorption at 363 nm wavelength and emission peak at 635 nm. Confocal microscopy images revealed the DVDMS was primarily localized in the cytoplasm, while no evident signal was detected within the nuclei. Flow cytometry analysis showed rapid intracellular uptake of DVDMS by two types of human colon cancer cells (HCT116 and RKO). Cell viability of HCT116 was tolerant with the concentration of DVDMS up to 20 µg/mL, while the case of RKO was 5 µg/mL. In comparison with the control group, the SDT-treated groups of these two types of human colon cancer cells showed significant increase in cellular apoptosis and necrosis ratio. Increased intracellular reactive oxygen species (ROS) production was detected, indicating the involvement of ROS in mediating SDT effects.

CONCLUSION

DVDMS results an effective sonosensitizer for the ultrasound-mediated cancer cell killing, and its anticancer effect seems to rely on its ability to produce ROS under ultrasound exposure.

Investigation of the tumoricidal effects of sonodynamic therapy in malignant glioblastoma brain tumors

OBJECTIVE

Glioblastoma is the most common primary brain tumor; survival is typically 12-18 months after diagnosis. We sought to study the effects of sonodynamic therapy (SDT) using 5-Aminolevulinic acid hydrochloride (5-ALA) and high frequency focused ultrasound (FUS) on 2 glioblastoma cell lines.

PROCEDURE

Rat C6 and human U87 glioblastoma cells were studied under the following conditions: 1 mM 5-ALA (5-ALA); focused ultrasound (FUS); 5-ALA and focused ultrasound (SDT); control. Studied responses included cell viability using an MTT assay, microscopic changes using phase contract microscopy, apoptotic induction through a caspase-3 assay, and apoptosis staining to quantify cell death.

RESULTS

SDT led to a marked decrease in cell extension and reduction in cell size. For C6, the MTT assay showed reductions in cell viability for 5-ALA, FUS, and SDT groups of 5%, 16%, and 47%, respectively compared to control (p < 0.05). Caspase 3 induction in C6 cells relative to control showed increases of 109%, 110%, and 278% for 5-ALA, FUS, and SDT groups, respectively (p < 0.05). For the C6 cells, caspase 3 staining positivity was 2.1%, 6.7%, 11.2%, and 39.8% for control, 5-ALA, FUS, and SDT groups, respectively. C6 Parp-1 staining positivity was 1.9%, 6.5%, 9.0%, and 37.8% for control, 5-ALA, FUS, and SDT groups, respectively. U87 cells showed similar responses to the treatments.

CONCLUSIONS

Sonodynamic therapy resulted in appreciable glioblastoma cell death as compared to 5-ALA or FUS alone. The approach couples two already FDA approved techniques in a novel way to treat the most aggressive and malignant of brain tumors. Further study of this promising technique is planned.

5-Aminolevulinic acid tumor paint and photodynamic therapy for myxofibrosarcoma: an in vitro study

Background

5-Aminolevulinic acid (5-ALA), a fluorescent contrast agent, has been used for tumor paint and photodynamic therapy (PDT) for various tumors, but its use with soft tissue sarcomas is not well documented. Myxofibrosarcoma, a subtype of soft tissue sarcoma with a high local recurrence rate, may benefit from similar types of treatment. The purpose of this study was to analyze the effects of 5-ALA tumor paint and PDT on a myxofibrosarcoma cell line.

Methods

Tumor paint was assessed by exposing micromass pellets of human adipose-derived stromal (ADS) cells or myxofibrosarcoma (MUG-Myx1) cells to 5-ALA. Cell pellets were then visualized using a microscope at established excitation and emission wavelengths. Corrected total cell fluorescence was calculated per accepted protocols. Photodynamic therapy was similarly assessed by exposing ADS and MUG-Myx1 cells to 5-ALA, with subsequent analysis via flow cytometry and real-time confocal microscopy.

Results

The use of 5-ALA tumor paint led to a selective fluorescence in MUG-Myx1 cells. Findings were confirmed by flow cytometry. Interestingly, flow cytometry results showed progressive selective cell death with increasing 5-ALA exposure as a result of the PDT effect. PDT was further confirmed using confocal microscopy, which revealed progressive cellular bubble formation consistent with advancing stages of cell death—a finding that was not seen in control ADS cells.

Conclusions

5-ALA tumor paint and PDT were successfully used on a human myxofibrosarcoma cell line (MUG-Myx1). Results from this study showed both selective fluorescent tagging and selective cytotoxicity of 5-ALA toward malignant myxofibrosarcoma cells, while sparing benign adipose control cells. This finding was further confirmed in a dramatic time-lapse video, visually confirming active, targeted cell death. 5-ALA’s two-pronged application of selective tumor identification and cytotoxicity may transform surgical and medical approaches for treating soft tissue sarcomas.

Effects of palmatine hydrochloride mediated photodynamic therapy on oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a common malignant tumor, accounting for about 7% of all malignant tumors. Palmatine hydrochloride (PaH) is the alkaloid constituent of Fibraurea tinctoria Lour. The present study aims to investigate the antitumor effect of photodynamic therapy (PDT) with PaH (PaH-PDT) on human OSCC cell lines both in vitro and in vivo. The results indicate that PaH-PDT exhibited a potent phototoxic effect in cell proliferation and produced cell apoptosis. PaH-PDT increased the percentage of cells in the G0/G1 phase and decreased the CDK2 and Cyclin E1 protein level. In addition, PaH-PDT markedly increased the generation of intracellular ROS, which can be suppressed using the ROS scavenger N-acetylcysteine (NAC). Furthermore, PaH-PDT increased the expression of p53 protein in vitro and in vivo. In vivo experiments revealed that the PaH-PDT resulted in an effective inhibition of tumor growth and prolonged the survival time of tumor-bearing mice. Moreover, no obvious signs of side effects or a drop in body weight was observed. These results suggested that PaH was a promising sensitizer that can be combined with light to produce significant anti-tumor effects in oral squamous cell carcinoma via enhanced ROS production and up-regulated expression of p53.

MR-guided Focused Ultrasound Facilitates Sonodynamic Therapy with 5-Aminolevulinic Acid in a Rat Glioma Model

Glioblastoma multiforme (GBM) continues to have a dismal prognosis and significant efforts are being made to develop more effective treatment methods. Sonodynamic therapy (SDT) is an emerging modality for cancer treatment which combines ultrasound with sonosensitizers to produce a localized cytotoxic effect. It has long been known that ultrasound exposure can cause both thermal and non-thermal bioeffects and it remains an open question to what degree does temperature impact the efficacy of SDT. In order to optimize the ultrasound parameters of SDT, transcranial MRI-guided focused ultrasound (MRgFUS) and real-time MRI thermometry were used to monitor the therapy in a rat brain tumor model. Experiments were performed using a C6 intracranial glioma tumor model in 37 male Sprague Dawley rats. Treatments were performed about 7 days following tumor implantation when the tumor reached 1-3 mm in diameter as determined by MRI. 5-aminolevulinic acid (5-ALA) was injected at a dose of 60 mg/kg six hours before sonication. MRgFUS at 1.06 MHz was delivered continuously at an in situ spatial-peak temporal-average intensity of 5.5 W/cm2 for 20 min. MR thermometry was acquired to monitor the temperature change in the brain during sonication. The tumor growth response for animals receiving 5-ALA alone, FUS alone, 5-ALA + FUS and a sham control group were evaluated with MRI every week following treatment. During 20 min of MRgFUS at 5.5 W/cm2, the temperature within the targeted brain tumor was elevated from 32.3 ± 0.5 °C and 37.2 ± 0.7 °C to 33.2 ± 0.9 °C and 38.4 ± 1.1 °C, respectively. Both the tumor growth inhibition and survival were significantly improved in the 5-ALA + FUS group with 32 °C or 37 °C as the starting core body (rectal) temperature. 5-ALA alone and FUS alone did not improve survival. These promising results indicate that relatively low power continuous wave transcranial MRgFUS in conjunction with 5-ALA can produce an inhibitory effect on rat brain tumor growth in the absence of thermal dose. Further investigation of the ultrasound parameters is needed to improve the therapeutic efficacy of MRgFUS and 5-ALA.

Experimental Data-Mining Analyses Reveal New Roles of Low-Intensity Ultrasound in Differentiating Cell Death Regulatome in Cancer and Non-cancer Cells via Potential Modulation of Chromatin Long-Range Interactions

Background: The mechanisms underlying low intensity ultrasound (LIUS) mediated suppression of inflammation and tumorigenesis remain poorly determined. Methods: We used microarray datasets from NCBI GEO Dataset databases and conducted a comprehensive data mining analyses, where we studied the gene expression of 299 cell death regulators that regulate 13 different cell death types (cell death regulatome) in cells treated with LIUS. Results: We made the following findings: (1) LIUS exerts a profound effect on the expression of cell death regulatome in cancer cells and non-cancer cells. Of note, LIUS has the tendency to downregulate the gene expression of cell death regulators in non-cancer cells. Most of the cell death regulator genes downregulated by LIUS in non-cancer cells are responsible for mediating inflammatory signaling pathways; (2) LIUS activates different cell death transcription factors in cancer and non-cancer cells. Transcription factors TP-53 and SRF- were induced by LIUS exposure in cancer cells and non-cancer cells, respectively; (3) As two well-accepted mechanisms of LIUS, mild hyperthermia and oscillatory shear stress induce changes in the expression of cell death regulators, therefore, may be responsible for inducing LIUS mediated changes in gene expression patterns of cell death regulators in cells; (4) LIUS exposure may change the redox status of the cells. LIUS may induce more of antioxidant effects in non-cancer cells compared to cancer cells; and (5) The genes modulated by LIUS in cancer cells have distinct chromatin long range interaction (CLRI) patterns to that of non-cancer cells. Conclusions: Our analysis suggests novel molecular mechanisms that may be utilized by LIUS to induce tumor suppression and inflammation inhibition. Our findings may lead to development of new treatment protocols for cancers and chronic inflammation.

Sonodynamic and sono-photodynamic therapy in oncology

In the present publication, authors have analyzed the results of using sonodynamic and sono-photodynamic therapy with photosensitizing agents of various classes (hematoporphyrin, 5-aminolevulinic acid, chlorin derivatives, etc.) in experimental oncology. In a number of in vitro and in vivo studies, the high antitumor efficacy of the above treatment methods has been proven. Ultrasonic treatment with a pulse frequency of 1–3 MHz and an intensity of 0.7 to 5 W/cm2 , independently and in combination with photo-irradiation of experimental tumors, can significantly improve the cytotoxic properties of photosensitizers. This became the basisfor testing the methodsin patients with malignant neoplasms of various localizations. Scientists fromSouth-East Asia presented the preliminary results of the use of sonodynamic and sono-photodynamic therapy with photosensitizers in the treatment of malignant pathology of the mammary gland, stomach, esophagus, prostate, lung and brain. Analysis of the obtained data indicates the absence of serious adverse events and an increase in the antitumor efficacy of treatment, which included these treatment methods with chlorin-type photosensitizers. 

Glaucocalyxin A reverses EMT and TGF-β1-induced EMT by inhibiting TGF-β1/Smad2/3 signaling pathway in osteosarcoma

Metastatic osteosarcoma usually has an unsatisfactory response to the current standard chemotherapy and causes poor prognosis. Currently, epithelial-mesenchymal transition (EMT) is reported as a critical event in osteosarcoma metastasis. Glaucocalyxin A, a bioactive ent-kauranoid diterpenoid, exerts anti-cancer effect on osteosarcoma by inducing apoptosis in previous study. However, the effect of Glaucocalyxin A on EMT and metastasis of osteosarcoma is unclear. In this study, we investigated the potential mechanisms of Glaucocalyxin A on EMT and metastasis of osteosarcoma. We found that Glaucocalyxin A inhibited migration and invasion of MG-63 and 143B cells. Moreover, Glaucocalyxin A increased the protein and mRNA levels of E-cadherin and decreased the protein and transcription expression of N-cadherin, Vimentin. Glaucocalyxin A also inhibited the protein and mRNA levels of EMT-associated transcription factor including Snail and Slug. Furthermore, Glaucocalyxin A inhibited transforming growth factor-β1 (TGF-β1)-induced migration, invasion and EMT of low-metastatic osteosarcoma U2OS cells. Glaucocalyxin A inhibited TGF-β-induced phosphorylation of Smad 2/3 in osteosarcoma U2OS cells. Finally, we established transplanted metastatic models of highly metastatic osteosarcoma 143B cells. Glaucocalyxin A inhibited lung metastasis in vivo. Interestingly, Glaucocalyxin A increased the protein expression of E-cadherin and reduced the protein expression of N-cadherin and Vimentin. Glaucocalyxin A inhibited the protein expression of Snail and Slug in vivo. In summary, this study demonstrated that Glaucocalyxin A inhibited EMT and TGF-β1-induced EMT by inhibiting TGF-β1/Smad2/3 signaling pathway in osteosarcoma. Therefore, Glaucocalyxin A might be a promising candidate against the metastasis of human osteosarcoma.

Adjuvant Biophysical Therapies in Osteosarcoma

Osteosarcoma (OS) is a primary bone sarcoma, manifesting as osteogenesis by malignant cells. Nowadays, patients’ quality of life has been improved, however continuing high rates of limb amputation, pulmonary metastasis and drug toxicity, remain unresolved issues. Thus, effective osteosarcoma therapies are still required. Recently, the potentialities of biophysical treatments in osteosarcoma have been evaluated and seem to offer a promising future, thanks in this field as they are less invasive. Several approaches have been investigated such as hyperthermia (HT), high intensity focused ultrasound (HIFU), low intensity pulsed ultrasound (LIPUS) and sono- and photodynamic therapies (SDT, PDT). This review aims to summarize in vitro and in vivo studies and clinical trials employing biophysical stimuli in osteosarcoma treatment. The findings underscore how the technological development of biophysical therapies might represent an adjuvant role and, in some cases, alternative role to the surgery, radio and chemotherapy treatment of OS. Among them, the most promising are HIFU and HT, which are already employed in OS patient treatment, while LIPUS/SDT and PDT seem to be particularly interesting for their low toxicity.

Sonodynamic Therapy: Advances and Challenges in Clinical Translation

Sonodynamic therapy (SDT) consists of the synergetic interaction between ultrasound and a chemical agent. In SDT, the cytotoxicity is triggered by ultrasonic stimuli, notably through cavitation. The unique features of SDT are relevant in the clinical context more than ever: the need for efficacy, accuracy, and safety while being noninvasive and preserving the patient's quality of life. However, despite the promising results of this technique, only a few clinical reports describe the use of SDT. The objective of this article is to provide an extensive overview of the clinical and preclinical research conducted in vivo on SDT, to identify the limitations, and to detail the developed strategies to overcome them.

Applications of Focused Ultrasound in Cerebrovascular Diseases and Brain Tumors

Oncology and cerebrovascular disease constitute two of the most common diseases afflicting the central nervous system. Standard of treatment of these pathologies is based on multidisciplinary approaches encompassing combination of interventional procedures such as open and endovascular surgeries, drugs (chemotherapies, anti-coagulants, anti-platelet therapies, thrombolytics), and radiation therapies. In this context, therapeutic ultrasound could represent a novel diagnostic/therapeutic in the armamentarium of the surgeon to treat these diseases. Ultrasound relies on mechanical energy to induce numerous physical and biological effects. The application of this technology in neurology has been limited due to the challenges with penetrating the skull, thus limiting a prompt translation as has been seen in treating pathologies in other organs, such as breast and abdomen. Thanks to pivotal adjuncts such as multiconvergent transducers, magnetic resonance imaging (MRI) guidance, MRI thermometry, implantable transducers, and acoustic windows, focused ultrasound (FUS) is ready for prime-time applications in oncology and cerebrovascular neurology. In this review, we analyze the evolution of FUS from the beginning in 1950s to current state-of-the-art. We provide an overall picture of actual and future applications of FUS in oncology and cerebrovascular neurology reporting for each application the principal existing evidences.

Enhancement of antitumor activity by using 5-ALA-mediated sonodynamic therapy to induce apoptosis in malignant gliomas: significance of high-intensity focused ultrasound on 5-ALA-SDT in a mouse glioma model

OBJECTIVEHigh invasiveness of malignant gliomas frequently causes early local recurrence of the tumor, resulting in extremely poor outcome. To control such recurrence, novel therapies targeted toward infiltrating glioma cells around the tumor border are required. Here, the authors investigated the antitumor activity of sonodynamic therapy (SDT) combined with a sonosensitizer, 5-aminolevulinic acid (5-ALA), on malignant gliomas to explore the possibility for clinical use of 5-ALA-mediated SDT (5-ALA-SDT).METHODSIn vitro cytotoxicity of 5-ALA-SDT was evaluated in U87 and U251 glioma cells and in U251Oct-3/4 glioma stemlike cells. Treatment-related apoptosis was analyzed using flow cytometry and TUNEL staining. Intracellular reactive oxygen species (ROS) were measured and the role of ROS in treatment-related cytotoxicity was examined by analysis of the effect of pretreatment with the radical scavenger edaravone. Effects of 5-ALA-SDT with high-intensity focused ultrasound (HIFU) on tumor growth, survival of glioma-transplanted mice, and histological features of the mouse brains were investigated.RESULTSThe 5-ALA-SDT inhibited cell growth and changed cell morphology, inducing cell shrinkage, vacuolization, and swelling. Flow cytometric analysis and TUNEL staining indicated that 5-ALA-SDT induced apoptotic cell death in all gliomas. The 5-ALA-SDT generated significantly higher ROS than in the control group, and inhibition of ROS generation by edaravone completely eliminated the cytotoxic effects of 5-ALA-SDT. In the in vivo study, 5-ALA-SDT with HIFU greatly prolonged survival of the tumor-bearing mice compared with that of the control group (p < 0.05). Histologically, 5-ALA-SDT produced mainly necrosis of the tumor tissue in the focus area and induced apoptosis of the tumor cells in the perifocus area around the target of the HIFU-irradiated field. The proliferative activity of the entire tumor was markedly decreased. Normal brain tissues around the ultrasonic irradiation field of HIFU remained intact.CONCLUSIONSThe 5-ALA-SDT was cytotoxic toward malignant gliomas. Generation of ROS by the SDT was thought to promote apoptosis of glioma cells. The 5-ALA-SDT with HIFU induced tumor necrosis in the focus area and apoptosis in the perifocus area of the HIFU-irradiated field, whereas the surrounding brain tissue remained normal, resulting in longer survival of the HIFU-treated mice compared with that of untreated mice. These results suggest that 5-ALA-SDT with HIFU may present a less invasive and tumor-specific therapy, not only for a tumor mass but also for infiltrating tumor cells in malignant gliomas.

Insight into ultrasound-mediated reactive oxygen species generation by various metal-porphyrin complexes

Ultrasound is used to trigger the cytotoxicity of chemical compounds, known as sonosensitisers, in an approach called sonodynamic therapy (SDT), which is under investigation herein. The generation of reactive oxygen species (ROS) has been proposed as the main biological occurrence that leads to the cytotoxic effects, which are achieved via the synergistic action of two components: the energy-absorbing sonosensitiser and ultrasound (US), which are both harmless per se. Despite some promising results, a lack of investigation into the mechanisms behind US sonosensitiser-mediated ROS generation has prevented SDT from reaching its full potential. The aim of this work is to investigate the US-responsiveness of a variety of metal-porphyrin complexes, free-base porphyrin and Fe(III), Zn(II) and Pd(II) porphyrin, by analyzing their ROS generation under US exposure and related bio-effects. All experiments were also carried out under light exposure and the results were used as references. Our results show that porphyrin ultrasound-responsiveness depends on the metal ion present, with Zn(II) and Pd(II) porphyrin being the most efficient in generating singlet oxygen and hydroxyl radicals. ROS production efficiency is lower after ultrasound exposure than after light exposure, because of the various physico-chemical mechanisms involved in sensitiser activation. US and porphyrin-mediated ROS generation is oxygen-dependent and the activation of porphyrin by US appears to be more compatible with sonoluminescence-based photo-activation rather than a radical path process that occurs via the homolytic bond rupture of water. Notably, the cytotoxicity results reported herein, which are mirrored by ex-cellulo data, confirm that the type of ROS generation achieved by the US activation of intracellular porphyrins is pivotal to the effectiveness of cancer cell killing.

The Combination of Glycolytic Inhibitor 2-Deoxyglucose and Microbubbles Increases the Effect of 5-Aminolevulinic Acid-Sonodynamic Therapy in Liver Cancer Cells

Sonodynamic therapy (SDT) overcomes the shortcoming of photodynamic therapy in the treatment of cancer. Previous studies indicated that the glycolysis inhibitor 2-deoxyglucose (2-DG) potentiated photodynamic therapy induced tumor cell death and microbubbles (MBs) improved the SDT performance. We hypothesized that the combination of 2-DG and MBs will increase the effect of 5-aminolevulinic acid (ALA)-SDT in HepG2 liver cancer cells. When cells were treated with 5-min ALA-SDT and 2-mmol/L 2-DG, the cell survival rate decreased to 73.0 ± 7.1% and 75.2 ± 7.9%, respectively. Furthermore, 2 mmol/L 2-DG increased 5-min ALA-SDT induced growth inhibition and augmented ALA-SDT induced cell apoptotic rate from 9.8 ± 0.7% to 17.4 ± 2.2%. In the combination group (2-DG and ALA-SDT group), HepG2 cells possessed typical apoptotic characters. 2-DG also increased ALA-SDT associated intracellular reactive oxygen species generation and loss of mitochondrial membrane potential. Moreover, SonoVue MBs had stimulatory function on cell viability inhibition, apoptosis, reactive oxygen species production and mitochondrial membrane potential loss for combination treatment. This study suggests a promising therapeutic strategy using a combination of 2-DG, MBs and ALA-SDT for treating liver cancer.

Emerging Applications of Therapeutic Ultrasound in Neuro-oncology: Moving Beyond Tumor Ablation

: Transcranial focused ultrasound (FUS) can noninvasively transmit acoustic energy with a high degree of accuracy and safety to targets and regions within the brain. Technological advances, including phased-array transducers and real-time temperature monitoring with magnetic resonance thermometry, have created new opportunities for FUS research and clinical translation. Neuro-oncology, in particular, has become a major area of interest because FUS offers a multifaceted approach to the treatment of brain tumors. FUS has the potential to generate cytotoxicity within tumor tissue, both directly via thermal ablation and indirectly through radiosensitization and sonodynamic therapy; to enhance the delivery of therapeutic agents to brain tumors by transiently opening the blood-brain barrier or improving distribution through the brain extracellular space; and to modulate the tumor microenvironment to generate an immune response. In this review, we describe each of these applications for FUS, the proposed mechanisms of action, and the preclinical and clinical studies that have set the foundation for using FUS in neuro-oncology.

ABBREVIATIONS

BBB, blood-brain barrierCED, convection-enhanced delivery5-Ala, 5-aminolevulinic acidFUS, focused ultrasoundGBM, glioblastoma multiformeHSP, heat shock proteinMRgFUS, magnetic resonance-guided focused ultrasoundpFUS, pulsed focused ultrasound.

Protoporphyrin IX-mediated sonodynamic therapy promotes autophagy in vascular smooth muscle cells

Sonodynamic therapy (SDT) is effective in treating intimal hyperplasia and promoting plaque stability in animal models. The present study aimed to evaluate the effects of SDT with the sonosensitizer protoporphyrin IX (PpIX) on vascular smooth muscle cell (VSMC) viability and autophagy. Cultured VSMCs cells were divided into the following groups: i) Control, ii) ultrasound, iii) PpIX and iv) SDT. Flow cytometry and laser confocal detection were used to measure Annexin V stained VSMCs following different treatments. Alterations in mitochondrial membrane potential (MMP) were evaluated via JC-1 staining. Autophagosome formation was observed using electron and fluorescence microscopy. Western blotting was used to analyze the expression levels of the autophagy markers light chain 3 (LC3-I) and LC3-II. The results demonstrated that SDT did not trigger apoptosis nor induce a significant decline in MMP of VSMCs. However, SDT significantly increased autophagasome formation and increased the LC3-II/LC3-I ratio. The findings demonstrated that PpIX-SDT increased autophagy without inducing mitochondrial-dependent apoptosis in VSMCs.

Artesunate Enhances the Cytotoxicity of 5-Aminolevulinic Acid-Based Sonodynamic Therapy against Mouse Mammary Tumor Cells In Vitro

Sonodynamic therapy (SDT) kills tumor cells through the synergistic effects of ultrasound (US) and a sonosensitizer agent. 5-Aminolevulinic acid (5-ALA) has been used as a sonodynamic sensitizer for cancer treatment. However, studies have shown that 5-ALA-based SDT has limited efficacy against malignant tumors. In this study, we examined whether artesunate (ART) could enhance the cytotoxicity of 5-ALA-based SDT against mouse mammary tumor (EMT-6) cells in vitro. In the ART, ART + US, ART + 5-ALA, and ART + 5-ALA + US groups, the cell survival rate correlated with ART concentration, and decreased with increasing concentrations of ART. Morphologically, many apoptotic and necrotic cells were observed in the ART + 5-ALA + US group. The percentage of reactive oxygen species-positive cells in the ART + 5-ALA + US group was also significantly higher than that in the 5-ALA group (p = 0.0228), and the cell death induced by ART + 5-ALA + US could be inhibited by the antioxidant N-acetylcysteine. These results show that ART offers great potential in enhancing the efficacy of 5-ALA-based SDT for the treatment of cancer. However, these results are only based on in vitro studies, and further in vivo studies are required.

Antiproliferative and Apoptosis-inducing Effect of exo-Protoporphyrin IX based Sonodynamic Therapy on Human Oral Squamous Cell Carcinoma

Sonodynamic therapy (SDT) is an innovative modality for cancer treatment. But the biological effect of SDT on oral squamous cell carcinoma has not been studied. Our previous study has shown that endo-Protoporphyrin IX based SDT (ALA-SDT) could induce apoptosis in human tongue squamous carcinoma SAS cells through mitochondrial pathway. Herein, we investigated the effect of exo- Protoporphyrin based SDT (PpIX-SDT) on SAS cells in vitro and in vivo. We demonstrated that PpIX-SDT increased the ratio of cells in the G₂/M phase and induced 3–4 times more cell apoptosis compared to sonocation alone. PpIX-SDT caused cell membrane damage prior to mitochondria damage and upregulated the expression of Fas and Fas L, while the effect was suppressed if cells were pre-treated with p53 inhibitor. Additionally, we examined the SDT-induced cell apoptosis in two cell lines with different p53 status. The increases of p53 expression and apoptosis rate in wild-type p53 SAS cells were found in the SDT group, while p53-mutated HSC-3 cells did not show such increase. Our data suggest that PpIX-SDT suppress the proliferation of SAS cells via arresting cell cycle at G₂/M phase and activating the extrinsic Fas-mediated membrane receptor pathway to induce apoptosis, which is regulated by p53.

Low-Intensity Ultrasound Combined with Hematoporphyrin Monomethyl Ether in the Treatment of Experimental Periodontitis in Rats

Objectives. This study aims to evaluate the efficacy of hematoporphyrin monomethyl ether- (HMME-) mediated sonodynamic therapy (SDT) on experimental periodontal disease in rats. Methods. Periodontal disease was induced by submerging ligatures at the first maxillary molar subgingival region in forty-eight male SD rats. After 30 days, the ligatures were removed. The rats were randomly allocated into four groups; the experimental SDT group was treated through hypodermic injection of 40 μg/mL HMME and 3 W/cm² low-intensity ultrasound irradiation (1 MHz, 600 s). Those in control groups received 40 μg/mL HMME alone (control 1 group) or 3 W/cm² ultrasound irradiation alone (control 2 group) or were subjected to neither HMME nor ultrasound (control 3 group). After 10 days of treatment, all rats were euthanized, the maxilla was obtained for histological examination, and the alveolar bone level was evaluated by histometric analysis. Results. The control groups showed more bone loss (P < 0.05) after 10 days of treatment than the SDT group. There is no significant difference among the control groups (P > 0.05). Conclusions. HMME mediated SDT was an effective therapy of experimental periodontal tissue in rats.