Sonodynamic effects of hematoporphyrin monomethyl ether on CNE-2 cells detected by atomic force microscopy

Ultrasound-Controlled Prodrug Activation: Emerging Strategies in Polymer Mechanochemistry and Sonodynamic Therapy

Ultrasound has gained prominence in biomedical applications due to its noninvasive nature and ability to penetrate deep tissue with spatial and temporal resolution. The burgeoning field of ultrasound-responsive prodrug systems exploits the mechanical and chemical effects of ultrasonication for the controlled activation of prodrugs. In polymer mechanochemistry, materials scientists exploit the sonomechanical effect of acoustic cavitation to mechanochemically activate force-sensitive prodrugs. On the other hand, researchers in the field of sonodynamic therapy adopt fundamentally distinct methodologies, utilizing the sonochemical effect (e.g., generation of reactive oxygen species) of ultrasound in the presence of sonosensitizers to induce chemical transformations that activate prodrugs. This cross-disciplinary review comprehensively examines these two divergent yet interrelated approaches, both of which originated from acoustic cavitation. It highlights molecular and materials design strategies and potential applications in diverse therapeutic contexts, from chemotherapy to immunotherapy and gene therapy methods, and discusses future directions in this rapidly advancing domain.

Nanomedicine/materdicine-enabled sonocatalytic therapy

The advent of numerous treatment modalities with desirable therapeutic efficacy has been made possible by the fast development of nanomedicine and materdicine, among which the ultrasound (US)-triggered sonocatalytic process as minimal or non-invasive method has been frequently employed for diagnostic and therapeutic purposes. In comparison to phototherapeutic approaches with inherent penetration depth limitations, sonocatalytic therapy shatters the depth limit of photoactivation and offers numerous remarkable prospects and advantages, including mitigated side effects and appropriate tissue-penetration depth. Nevertheless, the optimization of sonosensitizers and therapies remains a significant issue in terms of precision, intelligence and efficiency. In light of the fact that nanomedicine and materdicine can effectively enhance the theranostic efficiency, we herein aim to furnish a cutting-edge review on the latest progress and development of nanomedicine/materdicine-enabled sonocatalytic therapy. The design methodologies and biological features of nanomedicine/materdicine-based sonosensitizers are initially introduced to reveal the underlying relationship between composition/structure, sonocatalytic function and biological effect, in accompany with a thorough discussion of nanomedicine/materdicine-enabled synergistic therapy. Ultimately, the facing challenges and future perspectives of this intriguing sonocatalytic therapy are highlighted and outlined to promote technological advancements and clinical translation in efficient disease treatment.

Lipid bilayer-based biological nanoplatforms for sonodynamic cancer therapy

Sonodynamic therapy (SDT) has been developed as a promising alternative therapeutic modality for cancer treatment, involving the synergetic application of sonosensitizers and low-intensity ultrasound. However, the antitumor efficacy of SDT is significantly limited due to the poor performance of conventional sonosensitizers in vivo and the constrained tumor microenvironment (TME). Recent breakthroughs in lipid bilayer-based nanovesicles (LBBNs), including multifunctional liposomes, exosomes, and isolated cellular membranes, have brought new insights into the advancement of SDT. Despite their distinct sources and preparation methods, the lipid bilayer structure in common allows them to be functionalized in many comparable ways to serve as ideal nanocarriers against challenges arising from the tumor-specific sonosensitizer delivery and the complicated TME. In this review, we provide a comprehensive summary of the recent advances in LBBN-based SDT, with particular attention on how LBBNs can be engineered to improve the delivery efficiency of sonosensitizers and overcome physical, biological, and immune barriers within the TME for enhanced sonodynamic cancer therapy. We anticipate that this review will offer valuable guidance in the construction of LBBN-based nanosonosensitizers and contribute to the development of advanced strategies for next-generation sonodynamic cancer therapy.

Stimuli responsive nanosonosensitizers for sonodynamic therapy

Sonodynamic therapy (SDT) has gained significant attention in the treatment of deep tumors and multidrug-resistant (MDR) bacterial infections due to its high tissue penetration depth, high spatiotemporal selectivity, and noninvasive therapeutic method. SDT combines low-intensity ultrasound (US) and sonosensitizers to produce lethal reactive oxygen species (ROS) and external damage, which is the main mechanism behind this therapy. However, traditional organic small-molecule sonosensitizers display poor water solubility, strong phototoxicity, and insufficient targeting ability. Inorganic sonosensitizers, on the other hand, have low ROS yield and poor biocompatibility. These drawbacks have hindered SDT's clinical transformation and application. Hence, designing stimuli-responsive nano-sonosensitizers that make use of the lesion's local microenvironment characteristics and US stimulation is an excellent alternative for achieving efficient, specific, and safe treatment. In this review, we provide a comprehensive overview of the currently accepted mechanisms in SDT and discuss the application of responsive nano-sonosensitizers in the treatment of tumor and bacterial infections. Additionally, we emphasize the significance of the principle and process of response, based on the classification of response patterns. Finally, this review emphasizes the potential limitations and future perspectives of SDT that need to be addressed to promote its clinical transformation.

Ultrasound nanomedicine and materdicine

The conventional microbubble-based ultrasound biomedicine clinically plays a vital role in providing the dynamic detection of macro and microvasculature and disease theranostics. However, the intrinsic limitation of particle size severely decreases the treatment effectiveness due to their vascular transport characteristics, which promotes the development and application of multifunctional ultrasound-responsive nanomaterials. Herein, we put forward a research field of "ultrasound nanomedicine and materdicine", referring to the interdiscipline of ultrasound, nanobiotechnology and materials, which seeks to produce specific biological effects for addressing the challenges faced and dilemma of conventional ultrasound medicine. We comprehensively summarize the state-of-the-art scientific advances in the latest progress in constructing ultrasound-based platforms and ultrasound-activated sonosensitizers, ranging from the synthesis strategies, biological functions to ultrasound-triggered therapeutic applications. Ultimately, the unresolved challenges and clinical-translation potentials of ultrasound nanomedicine and materdicine are discussed and prospected in this evolving field.

Nanoscale Features of Gambogic Acid Induced ROS-Dependent Apoptosis in Esophageal Cancer Cells Imaged by Atomic Force Microscopy

Gambogic acid (GA), a kind of polyprenylated xanthone derived from Garcinia hanburyi tree, has showed spectrum anticancer effects both in vitro and in vivo with low toxicity. However, up to now, there is little information about the effects of GA on esophageal cancer. In this study, we aim to test the anticancer effects of GA on esophageal cancer EC9706 cells. We established a nanoscale imaging method based on AFM to evaluate the reactive oxygen species- (ROS-) mediated anticancer effects of GA on esophageal cancer regarding the morphological and ultrastructural changes of esophageal cancer cells. The obtained results demonstrated that GA could inhibit cell proliferation, induce apoptosis, induce cell cycle arrest, and induce mitochondria membrane potential disruption in a ROS-dependent way. And using AFM imaging, we also found that GA could induce the damage of cellular morphology and increase of membrane height distribution and membrane roughness in EC9706 cells, which could be reversed by the removal of GA-induced excessive intracellular ROS. Our results not only demonstrated the anticancer effects of GA on EC9706 cells in ROS-dependent mechanism but also strongly suggested AFM as a powerful tool for the detection of ROS-mediated cancer cell apoptosis on the basis of imaging.

Magnetic mediators for ultrasound theranostics

The theranostics paradigm is based on the concept of combining therapeutic and diagnostic modalities into one platform to improve the effectiveness of treatment. Combinations of multiple modalities provide numerous medical advantages and are enabled by nano- and micron-sized mediators. Here we review recent advancements in the field of ultrasound theranostics and the use of magnetic materials as mediators. Several subdisciplines are described in detail, including controlled drug delivery and release, ultrasound hyperthermia, magneto-ultrasonic heating, sonodynamic therapy, magnetoacoustic imaging, ultrasonic wave generation by magnetic fields, and ultrasound tomography. The continuous progress and improvement in theranostic materials, methods, and physical computing models have created undeniable possibilities for the development of new approaches. We discuss the prospects of ultrasound theranostics and possible expansions of other studies to the theranostic context.

Organic Sonosensitizers for Sonodynamic Therapy: From Small Molecules and Nanoparticles toward Clinical Development

Sonodynamic therapy (SDT) is a novel noninvasive therapeutic modality that combines low-intensity ultrasound and sonosensitizers. Versus photo-mediated therapy, SDT has the advantages of deeper tissue penetration, high accuracy, and less side effects. Sonosensitizers are critical for therapeutic efficacy during SDT and organic sonosensitizers are important because of their clear structure, easy monitoring, evaluation of drug metabolism, and clinical transformation. Notably, nanotechnology can be used in the field of sonosensitizers and SDT to overcome the inherent obstacles and achieve sustainable innovation. This review introduces organic small molecule sonosensitizers, nano organic sonosensitizers, and their clinical translation by providing ideas and references for the design of sonosensitizers and SDT so as to promote its transformation to clinical applications in the future.

Phototherapy and Sonotherapy of Melanoma Cancer Cells Using Nanoparticles of Selenium-Polyethylene Glycol-Curcumin as a Dual-Mode Sensitizer

Background:

As an alternative form of cancer therapy, photothermal therapy (PTT) and sonodynamic therapy (SDT) using nanomaterials are in development. Nanomaterials can act as energy absorber as well as anti-cancer agent.

Objective:

In this study, the effects of laser and ultrasound irradiation with Se-PEG-Cur nanoparticles were investigated on melanoma cancer.

Material and Methods:

In this experimental study, nanoparticles of selenium-polyethylene glycol-curcumin (Se-PEG-Cur) were synthesized, and their UV-vis absorption, particle size, zeta potential and photothermal conversion efficiency were determined. Se-PEG-Cur was then introduced as a novel 808-nm laser light absorbing agent as well as ultrasound (US) wave for treatment of C540 (B16/F10) cancer cells. Also, ROS generation in C540 (B16/F10) cancer cells was measured upon PTT and SDT using Se-PEG-Cur.

Results:

Mean size, zeta potential and photothermal conversion efficiency of Se-PEG-Cur were obtained as ~300 nm, 42.7 mV and 16.7%, respectively. Cell viability upon irradiation of the laser light or US waves with 100 µg mL^-1 Se-PEG-Cur were decreased to 33.9 and 22.9%, respectively.

Conclusion:

Intracellular ROS detection indicated that dual PTT and SDT in the presence of Se-PEG-Cur induced the highest ROS production. Se-PEG-Cur was therefore introduced as an absorbing agent of both laser light and US waves for cancer treatment.

Mesobuthus eupeus venom induced injury in the colorectal carcinoma cell line (HT29) through altering the mitochondria membrane stability

Objective(s):

The purpose of this study was to investigate cytotoxicity and membrane toxicity effects induced by Mesobuthus eupeus venom (MEV) on the HT-29 cell line.

Materials and Methods:

To determine the in vitro cytotoxicity via MTT assays, HT-29 (as cancer cell line) and Hek-293T (as normal cell) were treated through different concentrations of MEV, and cytotoxicity effects were then measured through assessment of mitochondrial membrane potential (ΔΨm), reactive oxygen species (ROS) generation, and apoptosis induction. The colony formation assay was performed to measure the antiproliferative effect of MEV on HT-29 cells. Nuclei alterations were also observed during apoptosis following DAPI staining. Besides, atomic force microscopy (AFM) was used to detect alterations in morphology and ultrastructure of the cells at a nanoscale level.

Results:

According to MTT and clonogenic assays, MEV caused a significant decrease in cell viability and proliferation of HT-29 cells while it did not have any impact on normal cells and the IC50 value was found to be 10 µg/ml. Induction of apoptosis was also confirmed by flowcytometric analysis in HT-29 cells. Moreover, the results indicated that MEV had led to a suppression of proliferation and induction of apoptosis through increased ROS and depolarization of mitochondria. Furthermore, AFM imaging demonstrated apoptosis cell death after being treated with MEV in HT-29 cells.

Conclusion:

This study showed that MEV had an antiproliferative effect on HT-29 cells by inducing apoptosis through the mitochondria signaling pathway. These findings suggested that MEV could be used as a promising natural remedy for cancer treatment.

IR780 loaded perfluorohexane nanodroplets for efficient sonodynamic effect induced by short-pulsed focused ultrasound

Inertial cavitation is crucial for the therapeutic effects of sonodynamic. Therefore, approaches that can induce highly efficient inertial cavitation should be of benefit for sonodynamic effect. Our previous study demonstrated that highly efficient inertial cavitation activity can be achieved through the combinatorial use of a short-pulsed focused ultrasound (SPFU) sequence and perfluorohexane (PFH) nanodroplets. Herein, we applied the SPFU sequence and PFH nanodroplets in sonodynamic. A hydrophobic sonosensitizer, IR780 iodine, was loaded inside denatured bovine serum albumin-shelled PFH (PFH@BSA-IR780) nanodroplets. The sonodynamic efficacy was validated by treating HeLa cervical cancer cells. Under SPFU exposure, PFH@BSA-IR780 nanodroplets were highly effective in promoting reactive oxygen species generation and inducing cancer cell death. A significant decrease in cell viability was achieved within just 10 s. Besides the cytotoxicity of ROS, the mechanical bioeffects of inertial cavitation also led to severe cell death resulting from higher acoustic power or the longer treatment time. The application of the SPFU sequence coupled with PFH@BSA-IR780 nanodroplets is a promising strategy for efficient sonodynamic.

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.

Nanoparticle-assisted ultrasound: A special focus on sonodynamic therapy against cancer

At present, ultrasound radiation is broadly employed in medicine for both diagnostic and therapeutic purposes at various frequencies and intensities. In this review article, we focus on therapeutically-active nanoparticles (NPs) when stimulated by ultrasound. We first introduce the different ultrasound-based therapies with special attention to the techniques involved in the oncological field, then we summarize the different NPs used, ranging from soft materials, like liposomes or micro/nano-bubbles, to metal and metal oxide NPs. We therefore focus on the sonodynamic therapy and on the possible working mechanisms under debate of NPs-assisted sonodynamic treatments. We support the idea that various, complex and synergistics physical-chemical processes take place during acoustic cavitation and NP activation. Different mechanisms are therefore responsible for the final cancer cell death and strongly depends not only on the type and structure of NPs or nanocarriers, but also on the way they interact with the ultrasonic pressure waves. We conclude with a brief overview of the clinical applications of the various ultrasound therapies and the related use of NPs-assisted ultrasound in clinics, showing that this very innovative and promising approach is however still at its infancy in the clinical cancer treatment.

EGFR-targeting PLGA-PEG nanoparticles as a curcumin delivery system for breast cancer therapy

Poor bioavailability and non-specificity of chemotherapeutic agents are major challenges in breast cancer treatment. Antibodies and small molecules that block cell signaling pathways have shown promise in the clinic, but their application is also limited by the high costs and treatment dosages required. Novel therapies that aim to rapidly and specifically target malignant cells with long-lasting impact in the tumor microenvironment may ultimately improve clinical outcome in cancer patients. Here, we demonstrate that epidermal growth factor receptor (EGFR)-targeting GE11 peptides conjugated with PEGylated polylactic-co-glycolic acid (PLGA) nanoparticles can be used to effectively deliver an anti-cancer agent, curcumin, into EGFR-expressing MCF-7 cells in vitro and in vivo. Treatment of breast cancer cells and tumor-bearing mice with these curcumin-loaded nanoparticles gave rise to reduced phosphoinositide 3-kinase signaling, decreased cancer cell viability, attenuated drug clearance from the circulation, and suppressed tumor burden compared with free curcumin or non-EGFR targeting nanoparticles. The targeted nanoscale drug delivery system we describe here may provide a new strategy for the design of targeted cancer therapy vectors. Our study provides evidence that the efficacy of pharmacologic anti-cancer agents can be enhanced through their delivery in the form of modified nanoparticles that effectively target specific malignant cell types.

Study of morphological and mechanical features of multinuclear and mononuclear SW480 cells by atomic force microscopy

This article studies the morphological and mechanical features of multinuclear and mononuclear SW480 colon cancer cells by atomic force microscopy to understand their drug-resistance. The SW480 cells were incubated with the fullerenol concentrations of 1 mg/ml and 2 mg/ml. Morphological and mechanical features including the height, length, width, roughness, adhesion force and Young's modulus of three multinuclear cell groups and three mononuclear cell groups were imaged and analyzed. It was observed that the features of multinuclear cancer cells and mononuclear cancer cells were significantly different after the treatment with fullerenol. The experiment results indicated that the mononuclear SW480 cells were more sensitive to fullerenol than the multinuclear SW480 cells, and the multinuclear SW480 cells exhibited a stronger drug-resistance than the mononuclear SW480 cells. This work provides a guideline for the treatments of multinuclear and mononuclear cancer cells with drugs.

Immunomodulatory effects of polysaccharide compounds in macrophages revealed by high resolution AFM

Polysaccharide compounds (PCs), which composed of different kinds of polysaccharides always isolated from different kinds of traditional Chinese medicine, are now attracting more and more attentions due to their strong immunomodulatory activities beyond the corresponding one-component polysaccharides. In this study, we demonstrated for the first time that PCs-1 and PCs-2 had strong immunomodulatory effects on macrophages both in in vitro and in vivo models by atomic force microscopy (AFM). By high resolution AFM imaging, PCs-1 and PCs-2 were found to inhibit LPS induced cell surface particle size and roughness increase in RAW264.7 macrophages, demonstrating the anti-inflammatory effects of PCs-1 and PCs-2 on macrophages. PCs-1 and PCs-2 were also proved to increase the particle size and roughness of resting RAW264.7 macrophages, which suggested that PCs could activate resting RAW264.7 macrophages. And additionally, PCs-1 and PCs-2 were also found to reverse the surface particle size and roughness decrease of peritoneal macrophages isolated from cyclophosphamide induced immunosuppressive mice, suggesting the activation effects of PCs-1 and PCs-2 on immunosuppressive macrophages. These results further enhanced our understanding of macrophage activations by direct imaging of cell surface ultrastructure and also highlighted AFM as a novel nanotool for macrophage detections. And most importantly, these results also indicated the outstanding immunomodulatory effects of PCs on macrophages, which therefore suggested that PCs could be served as a kind of novel immunomodulatory agents that would benefit human health. SCANNING 38:792-801, 2016. © 2016 Wiley Periodicals, Inc.

Synthesis, characterization and anticancer activity of kaempferol-zinc(II) complex

According to the previous studies, the anticancer activity of flavonoids could be enhanced when they are coordinated with transition metal ions. In this work, kaempferol-zinc(II) complex (kaempferol-Zn) was synthesized and its chemical properties were characterized by UV-VIS, FT-IR, (1)H NMR, elemental analysis, electrospray mass spectrometry (ES-MS) and fluorescence spectroscopy, which showed that the synthesized complex was coordinated with a Zn(II) ion via the 3-OH and 4-oxo groups. The anticancer effects of kaempferol-Zn and free kaempferol on human oesophageal cancer cell line (EC9706) were compared. MTT results demonstrated that the killing effect of kaempferol-Zn was two times higher than that of free kaempferol. Atomic force microscopy (AFM) showed the morphological and ultrastructural changes of cellular membrane induced by kaempferol-Zn at subcellular or nanometer level. Moreover, flow cytometric analysis indicated that kaempferol-Zn could induce apoptosis in EC9706 cells by regulating intracellular calcium ions. Collectively, all the data showed that kaempferol-Zn might be served as a kind of potential anticancer agent.

Investigation of quercetin-induced HepG2 cell apoptosis-associated cellular biophysical alterations by atomic force microscopy

Quercetin, a wildly distributed bioflavonoid, has been proved to possess excellent antitumor activity on hepatocellular carcinoma (HCC). In the present study, the biophysical properties of HepG2 cells were qualitatively and quantitatively determined using high resolution atomic force microscopy (AFM) to understand the anticancer effects of quercetin on HCC cells at nanoscale. The results showed that quercetin could induce severe apoptosis in HepG2 cells through arrest of cell cycle and disruption of mitochondria membrane potential. Additionally, the nuclei and F-actin structures of HepG2 cells were destroyed by quercetin treatment as well. AFM morphological data showed some typical apoptotic characterization of HepG2 cells with increased particle size and roughness in the ultrastructure of cell surface upon quercetin treatment. As an important biophysical property of cells, the membrane stiffness of HepG2 cells was further quantified by AFM force measurements, which indicated that HepG2 cells became much stiffer after quercetin treatment. These results collectively suggest that quercetin can be served as a potential therapeutic agent for HCC, which not only extends our understanding of the anticancer effects of quercetin against HCC cells into nanoscale, but also highlights the applications of AFM for the investigation of anticancer drugs.

Nanoparticles in sonodynamic therapy: state of the art review

The different types and advantages of nanoparticles in sonodynamic therapy.

Qualitative and Quantitative Analysis of ROS-Mediated Oridonin-Induced Oesophageal Cancer KYSE-150 Cell Apoptosis by Atomic Force Microscopy

High levels of intracellular reactive oxygen species (ROS) in cells is recognized as one of the major causes of cancer cell apoptosis and has been developed into a promising therapeutic strategy for cancer therapy. However, whether apoptosis associated biophysical properties of cancer cells are related to intracellular ROS functions is still unclear. Here, for the first time, we determined the changes of biophysical properties associated with the ROS-mediated oesophageal cancer KYSE-150 cell apoptosis using high resolution atomic force microscopy (AFM). Oridonin was proved to induce ROS-mediated KYSE-150 cell apoptosis in a dose dependent manner, which could be reversed by N-acetylcysteine (NAC) pretreatment. Based on AFM imaging, the morphological damage and ultrastructural changes of KYSE-150 cells were found to be closely associated with ROS-mediated oridonin-induced KYSE-150 cell apoptosis. The changes of cell stiffness determined by AFM force measurement also demonstrated ROS-dependent changes in oridonin induced KYSE-150 cell apoptosis. Our findings not only provided new insights into the anticancer effects of oridonin, but also highlighted the use of AFM as a qualitative and quantitative nanotool to detect ROS-mediated cancer cell apoptosis based on cell biophysical properties, providing novel information of the roles of ROS in cancer cell apoptosis at nanoscale.

Atomic force microscopy based investigations of anti-inflammatory effects in lipopolysaccharide-stimulated macrophages

A new method based on atomic force microscopy (AFM) was developed to investigate the anti-inflammatory effects of drugs on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. The LPS-stimulated RAW264.7 macrophage cell line is a widely used in vitro cell model for the screening of anti-inflammatory drugs or the study of anti-inflammatory mechanisms. In this work, the inhibitory effects of dexamethasone and quercetin on LPS-CD14 receptor binding in RAW264.7 macrophages was probed by LPS-functionalized tips for the first time. Both dexamethasone and quercetin were found to inhibit LPS-induced NO production, iNOS expression, IκBα phosphorylation, and IKKα/β phosphorylation in RAW264.7 macrophages. The morphology and ultrastructure of RAW264.7 macrophages were determined by AFM, which indicated that dexamethasone and quercetin could inhibit LPS-induced cell surface particle size and roughness increase in RAW264.7 macrophages. The binding of LPS and its receptor in RAW264.7 macrophages was determined by LPS-functionalized AFM tips, which demonstrated that the binding force and binding probability between LPS and CD14 receptor on the surface of RAW264.7 macrophages were also inhibited by dexamethasone or quercetin treatment. The obtained results imply that AFM, which is very useful for the investigation of potential targets for anti-inflammatory drugs on native macrophages and the enhancement of our understanding of the anti-inflammatory effects of drugs, is expected to be developed into a promising tool for the study of anti-inflammatory drugs.

Upconversion nanoparticle-mediated photodynamic therapy induces THP-1 macrophage apoptosis via ROS bursts and activation of the mitochondrial caspase pathway

Atherosclerosis (AS) is the most vital cardiovascular disease, which poses a great threat to human health. Macrophages play an important role in the progression of AS. Photodynamic therapy (PDT) has emerged as a useful therapeutic modality not only in the treatment of cancer but also in the treatment of AS. The purpose of this study was to determine the molecular mechanisms underlying the activity of PDT, using mesoporous-silica-coated upconversion fluorescent nanoparticles encapsulating chlorin e6 (UCNPs-Ce6) in the induction of apoptosis in THP-1 macrophages. Here, we investigated the ability of UCNPs-Ce6-mediated PDT to induce THP-1 macrophage apoptosis by facilitating the induction of reactive oxygen species (ROS) and regulation of mitochondrial permeability transition pore (MPTP) to depolarize mitochondrial membrane potential (MMP). Both Bax translocation and the release of cytochrome C were examined using immunofluorescence and Western blotting. Our results indicated that the levels of ROS were significantly increased in the PDT group, resulting in both MPTP opening and MMP depolarization, which led to apoptosis. In addition, immunofluorescence and Western blotting revealed that PDT induced both Bax translocation and the release of cytochrome C, as well as upregulation of cleaved caspase-9, cleaved caspase-3, and cleaved poly(ADP-ribose) polymerase. Therefore, we demonstrated that UCNPs-Ce6-mediated PDT induces apoptosis in THP-1 macrophages via ROS bursts. The proapoptotic factor Bax subsequently translocates from the cytosol to the mitochondria, resulting in the MPTP opening and cytochrome C release. This study demonstrated the great potential of UCNPs-Ce6-mediated PDT in the treatment of AS.

Sonodynamic effect of hematoporphyrin monomethyl ether on ligature-induced periodontitis in rats

Objectives

The aim of this study was to perform a histological evaluation of sonodynamic therapy (SDT) of hematoporphyrin monomethyl ether (HMME) on artificially induced periodontal disease in rats.

Methods

Submerging ligatures were placed at the subgingival region of the first maxillary molar in rats. Eighty rats were randomly assigned into four groups: group 1 received no treatment; group 2 was subjected to 50 μg/mL HMME alone; group 3 was treated with low-intensity ultrasound alone (1 W/cm²); and group 4 was treated with 50 μg/mL HMME plus ultrasound irradiation (1 MHz, 30 minutes). Ten rats in each group were euthanized at 7 and 15 days, and periodontal tissue samples were taken for histological examination.

Results

The animals treated by SDT showed less bone loss (P<0.05) at all experimental periods than the other three groups. No significant differences were found between the control and HMME groups (P>0.05).

Conclusion

Our results suggest that HMME-mediated SDT can effectively alleviate the periodontal tissue destruction in artificially induced periodontitis in rats. Hence, SDT may have good clinic potential as a noninvasive treatment of periodontal diseases.

The efficacy and mechanism of apoptosis induction by hypericin-mediated sonodynamic therapy in THP-1 macrophages

Purpose

To investigate the sonoactivity of hypericin (HY), together with its sonodynamic effect on THP-1 macrophages and the underlying mechanism.

Materials and methods

CCK-8 was used to examine cell viability. Confocal laser scanning microscopy was performed to assess the localization of HY in cells, reactive oxygen species (ROS) generation, and opening of the mitochondrial permeability transition pore (mPTP) after different treatments. Apoptosis was analyzed using Hoechst–propidium iodide and transmission electron microscopy. Mitochondrial membrane potential (ΔΨm) collapse was detected via fluorescence microscopy. Lipoprotein oxidation was determined in malondialdehyde (MDA) assays. Western blotting was conducted to determine the translocation of BAX and cytochrome C and the expression of apoptosis-related proteins.

Results

HY was sublocalized among the nuclei and the mitochondria, endoplasmic reticulum, Golgi apparatus, and lysosome in the cytosol of THP-1 macrophages. Under low-intensity ultrasound irradiation, HY significantly decreased cell viability and induced apoptosis. Furthermore, greater ROS generation, higher MDA levels, and greater ΔΨm loss were observed in the sonodynamic therapy (SDT) group. Both ROS generation and MDA levels were significantly reduced by the ROS scavenger N-acetyl cysteine (NAC) and the singlet oxygen scavenger sodium azide. Most of the loss of ΔΨm was inhibited by pretreatment with NAC, sodium azide, and the mPTP inhibitor cyclosporin A (CsA). mPTP opening was induced upon SDT but was reduced by pretreatment with bongkrekic acid, 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid disodium, CsA, and NAC. Western blot analyses revealed translocation of BAX and cytochrome C, downregulated expression of Bcl-2, and upregulated expression of cleaved caspase-9, cleaved caspase-3, and cleaved poly(ADP-ribose) polymerase in the SDT group, which were reversed by NAC.

Conclusion

HY mediated SDT-induced apoptosis in THP-1 macrophages via ROS generation. Then, the proapoptotic factor BAX translocated from the cytosol to the mitochondria, increasing the ratio of BAX/Bcl-2, and the mPTP opened to release cytochrome C. This study demonstrated the great potential of HY-mediated SDT for treating atherosclerosis.

Antiproliferative effects of cinobufacini on human hepatocellular carcinoma HepG2 cells detected by atomic force microscopy

AIM: To investigate the antiproliferative activity of cinobufacini on human hepatocellular carcinoma HepG2 cells and the possible mechanism of its action.

METHODS: HepG2 cells were treated with different concentrations of cinobufacini. Cell viability was measured by methylthiazolyl tetrazolium (MTT) assay. Cell cycle distribution was analyzed by flow cytometry (FCM). Cytoskeletal and nuclear alterations were observed by fluorescein isothiocyanate-phalloidin and DAPI staining under a laser scanning confocal microscope. Changes in morphology and ultrastructure of cells were detected by atomic force microscopy (AFM) at the nanoscale level.

RESULTS: MTT assay indicated that cinobufacini significantly inhibited the viability of HepG2 cells in a dose-dependent manner. With the concentration of cinobufacini increasing from 0 to 0.10 mg/mL, the cell viability decreased from 74.9% ± 2.7% to 49.41% ± 2.2% and 39.24% ± 2.1% (P < 0.05). FCM analysis demonstrated cell cycle arrest at S phase induced by cinobufacini. The immunofluorescence studies of cytoskeletal and nuclear morphology showed that after cinobufacini treatment, the regular reorganization of actin filaments in HepG2 cells become chaotic, while the nuclei were not damaged seriously. Additionally, high-resolution AFM imaging revealed that cell morphology and ultrastructure changed a lot after treatment with cinobufacini. It appeared as significant shrinkage and deep pores in the cell membrane, with larger particles and a rougher cell surface.

CONCLUSION: Cinobufacini inhibits the viability of HepG2 cells via cytoskeletal destruction and cell membrane toxicity.

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

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

AFM-based bivariate morphological discrimination of apoptosis induced by photodynamic therapy using photosensitizer-functionalized gold nanoparticles

Typical examples of the morphology of one viable and one apoptotic cell together with the statistical analysis of a larger cell ensemble subsequent to photodynamic treatment.

The effects of Ce6-mediated sono-photodynamic therapy on cell migration, apoptosis and autophagy in mouse mammary 4T1 cell line

PURPOSE

Sono-Photodynamic therapy (SPDT) is an alternative therapy which claims to enhance the anti-cancer effects by combining sonodynamic therapy (SDT) with photodynamic therapy (PDT). In the present study, we investigated the effects of chlorin e6 (Ce6) mediated SPDT on migration, apoptosis and autophagy in mouse mammary 4T1 cancer cells, and its underlying mechanisms.

MATERIALS

Cell migration was determined by wound healing assay. Apoptosis was analyzed using annexin V-PE/7-ADD staining as well as Hoechst 33342 staining. Changes of mitochondria membrane potential (MMP) was evaluated by flow cytometry. Formation of acidic vesicular organelles (AVOs) during autophagy was observed with fluorescence microscope by MDC staining. Immunofluorescence assays were performed to detect the co-localization of LC3 and Lamp2. Western blotting was employed to analyze the activity of the apoptosis related proteins Caspase-3, PARP, Bax and Bcl-2, as well as the autophagy associated processing of LC3-I to LC3-II and Beclin-1 expression.

RESULTS

Ce6 mediated SPDT further enhanced cell migration inhibition, significantly triggered cell apoptosis, nuclear condensation and MMP drop. Cleaved Caspase-3 and PARP increased dramatically after Ce6-SPDT, accompanied by decreased Bcl-2 expression, while the expression of Bax remained stable. Additionally, AVOs formation, co-localization of LC3 and Lamp2 occurred following Ce6-SPDT and simultaneously accompanied by LC3-II processing and increased Beclin-1 expression.

CONCLUSIONS

Ce6-SPDT could enhance cell migration inhibition, and induce mitochondria-dependent apoptosis as well as autophagy in 4T1 cells.

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.

Efficacy of chlorin e6-mediated sono-photodynamic therapy on 4T1 cells

PURPOSE

The present study aims to investigate the antitumor effect and possible mechanisms of chlorin e6 (Ce6)-mediated sono-photodynamic therapy (Ce6-SPDT) on murine 4T1 mammary cancer cells in vitro.

MATERIALS

Cellular uptake and intracellular distribution of Ce6 in 4T1 cells were detected by flow cytometry and confocal microscope. Cells after loading with 1 μg/mL Ce6 were exposed to ultrasound at 1.0 MHz for up to 1 minute with an intensity of 0.36 W/cm2 and laser light with total radiation dose of 1.2 J/cm2. Cell viability and clonogenicity were determined by MTT assay and colony formation assay. Apoptosis was analyzed by DAPI staining, Western blots were used to detect the activity of Caspase-3. DNA damage, mitochondrial membrane potential (MMP), and intracellular reactive oxygen species (ROS) of 4T1 cells were also evaluated by flow cytometry. FD500 was employed to detect changes of membrane permeability after ultrasound.

RESULTS

Ce6 rapidly entered 4T1 cells within 4 hours after it has been added and displayed a mitochondria-localization pattern. Compared with sonodynamic therapy (SDT) and photodynamic therapy (PDT) alone, the combined SPDT treatment further enhanced cell viability loss, DNA damage, and clonogenicity inhibition. DAPI staining and western blots analysis reflected that cells with apoptotic morphological characteristics and the activity of Caspase-3 were apparently increased in the combined group. Besides, SPDT caused obvious MMP loss and intracellular ROS generation at early 1 hour post treatment. Interestingly, the SPDT induced cell viability loss and cell apoptosis was greatly inhibited by pre-treatment with ROS scavenger N-acetylcysteine and Caspase inhibitor z-VAD-fmk. FD500 detection showed that ultrasound enhanced cell membrane permeability, implying much higher uptake of Ce6 might be involved in PDT therapy by pre-ultrasound treatment.

CONCLUSIONS

The findings demonstrated that Ce6-mediated SPDT enhanced the antitumor efficacy on 4T1 cells compared with SDT and PDT alone, a Caspase-dependent apoptosis and loss of MMP, generation of ROS may be involved.

Ultrasound enhances the efficacy of chlorin E6-mediated photodynamic therapy in MDA-MB-231 cells

Sono-photodynamic therapy (SPDT) is a new modality for cancer treatment. Some studies have reported enhanced tumor cytotoxicity when sonodynamic therapy (SDT) is combined with photodynamic therapy (PDT). In this study, we investigated the cytotoxic effect of SPDT-activated chlorin e6 (Ce6) on MDA-MB-231 cells. Ce6 was found to localize mainly in mitochondria, with maximal uptake within 4 h. Cell survival was estimated by MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltertrazolium bromide tetrazolium) assay 24 h after irradiation; the combined therapy enhanced cytotoxicity to a greater extent. Apoptosis was analyzed using annexin V-PE/7-ADD (7-aminoactinomycin D) staining as well as DAPI (4', 6-diamidino-2-phenylindole) staining, and the results indicated that the cells with apoptotic characteristics were significantly increased in groups given combined therapy. Rhodamine-123 staining and cytochrome c release revealed more serious damage of mitochondria after combined treatment. The generation of reactive oxygen species detected by flow cytometry was greatly increased in cells treated with the combination therapy, and the loss in cell viability could be effectively rescued with the reactive oxygen species inhibitor N-acetylcysteine. Moreover, enhancement of cell membrane permeability after ultrasound treatment was evaluated using FD-500, and it was found that the much higher uptake of Ce6 might be involved in PDT therapy with pre-treatment ultrasound. These results suggest that ultrasound enhances the cytotoxicity of Ce6-mediated PDT, possibly because of the increased intracellular Ce6 level and ROS formation by ultrasound pre-treatment.

Curcumin disturbed cell-cycle distribution of HepG2 cells via cytoskeletal arrangement

Due to its extensive antitumor activity, curcumin has been focused on by more researchers. But, its antiproliferative mechanisms are still unknown. Here we studied the antiproliferative activity of curcumin in human liver cancer HepG2 cells. In order to analyze the cytotoxic activity and anticancer mechanisms of curcumin, we carried out cytotoxicity tests using 3-[4,5-dimethyl-2-thiazolyl]-2,5 diphenyltetrazolium bromide (MTT) assay. The HepG2 cell cycle distribution and the expression of tubulin were detected by flow cytometry. Alterations in morphological and cytoskeletal properties of HepG2 cells were investigated using atomic force microscopy (AFM). Simultaneously, the effects of curcumin on the growth and proliferation of HepG2 cells were also assayed by MTT method. Cells were incubated with different doses of curcumin (0-80 μmol/l) for 24 h, the cell viability decreased from 91.10 ± 3.2% to 10.84 ± 4.0%, and the 50% inhibiting concentration (IC50 ) was 23.15 ± 0.37 μmol/l. Moreover, flow cytometry quantitatively detected that curcumin treatment resulted in a dose-dependent accumulation of HepG2 cells in G2/M phase with concomitant losses from G0/G1 phase, so curcumin caused cell-cycle arrest at G2/M phase. Furthermore, we discovered that curcumin was able to upregulate the expression of tubulin in HepG2 cells. In addition, AFM analysis including cell-membrane structure and cytoskeleton networks is helpful to explain the relationship between the changes of cells and external pharmacologic stimulation.

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.

AFM investigation on Ox-LDL-induced changes in cell spreading and cell-surface adhesion property of endothelial cells

The integrity and adhesion properties of endothelium play vital roles during atherosclerosis. It is well known that oxidized low-density lipoprotein (Ox-LDL) influences many physiological activities or mechanical properties of endothelial cells. However, the effects of Ox-LDL on the integrity and nonspecific adhesion properties of endothelial cells are still unclear. In this study, using the topographical imaging and force measurement functions of atomic force microscopy (AFM), we found that Ox-LDL can transiently weaken the integrity of endothelium by impairing cell spreading of endothelial cells and decrease the attachment of irrelevant blood cells to endothelium by impairing the nonspecific adhesion property of endothelial cells. The AFM-based data provide important information for understanding the effects of Ox-LDL on endothelial cells or during atherogenesis.