Anti-metastatic and pro-apoptotic effects elicited by combination photodynamic therapy with sonodynamic therapy on breast cancer both in vitro and in vivo

Advanced Strategies for Strengthening the Immune Activation Effect of Traditional Antitumor Therapies

The utilization of traditional therapies (TTS), such as chemotherapy, reactive oxygen species-based therapy, and thermotherapy, to induce immunogenic cell death (ICD) in tumor cells has emerged as a promising strategy for the activation of the antitumor immune response. However, the limited effectiveness of most TTS in inducing the ICD effect of tumors hinders their applications in combination with immunotherapy. To address this challenge, various intelligent strategies have been proposed to strengthen the immune activation effect of these TTS, and then achieve synergistic antitumor efficacy with immunotherapy. These strategies primarily focus on augmenting the tumor ICD effect or facilitating the antigen (released by the ICD tumor cells) presentation process during TTS, and they are systematically summarized in this review. Finally, the existing bottlenecks and prospects of TTS in the application of tumor immune regulation are also discussed.

Indocyanine green fluorescence applied to gynecologic oncology: beyond sentinel lymph node

Indocyanine green (ICG), a well-known molecule employed in medicine for over five decades, has emerged as a versatile dye widely embraced across various surgical disciplines. In gynecologic oncology, its prevalent use revolves around the detection of sentinel lymph nodes. However, the true potential of ICG extends beyond this singular application, owing to its pragmatic utility, cost-effectiveness, and safety profile. Furthermore, ICG has been introduced in the theranostic landscape, marking a significant juncture in the evolution of its clinical utility. This narrative review aims to describe the expanding horizons of ICG fluorescence in gynecologic oncology, beyond the sentinel lymph node biopsy. The manifold applications reported within this manuscript include: 1) lymphography; 2) angiography; 3) nerve visualization; 4) ICG-driven resections; and 5) theranostic. The extensive exploration across these numerous applications, some of which are still in the preclinical phase, serves as a hypothesis generator, aiming to stimulate the development of clinical studies capable of expanding the use of this drug in our field, enhancing the care of gynecological cancer patients.

Phthalocyanine-based probes in alleviating or evading tumour-hypoxia for enhanced photo- and/ sono-mediated therapeutic efficacies

This review discusses the possible methods for improving therapeutic efficacies of phthalocyanine (Pcs) -based therapeutic probes in photo- and sono-dynamic therapies under hypoxic conditions. Herein, the structural design strategies including varying the central metal, position substituents and the effects of adjuvant used in supplementing the therapeutics activities of Pcs or formation of NPs are discussed for cancer therapies in hypoxic conditions. Different mechanisms induced for cell death influenced by the compositions of the Pcs-probes are discussed. The focus mainly highlights the oxygen (O2) -dependent mechanisms including methods of supplementing tumour microenvironment O2-concentrations to promote PDT or SDT therapies. Alternatively, O2-independent mechanisms mainly used to evade hypoxia by stimulating anticancer processes that don't require O2 to initiate cell death, such as the Fenton reaction or thermal ablation effects.

MnO2/Ce6 microbubble-mediated hypoxia modulation for enhancing sono-photodynamic therapy against triple negative breast cancer

Sono-photodynamic therapy (SPDT) has emerged as a promising treatment modality for triple negative breast cancer (TNBC). However, the hypoxic tumor microenvironment hinders the application of SPDT. Herein, in this study, a multifunctional platform (MnO2/Ce6@MBs) was designed to address this issue. A sono-photosensitizer (Ce6) and a hypoxia modulator (MnO2) were loaded into microbubbles and precisely released within tumor tissues under ultrasound irradiation. MnO2in situ reacted with the excess H2O2 and H+ and produced O2 within the TNBC tumor, which alleviated hypoxia and augmented SPDT by increasing ROS generation. Meanwhile, the reaction product Mn2+ was able to achieve T1-weighted MRI for enhanced tumor imaging. Additionally, Ce6 and microbubbles served as a fluorescence imaging contrast agent and a contrast-enhanced ultrasound imaging agent, respectively. In in vivo anti-tumor studies, under the FL/US/MR imaging guidance, MnO2/Ce6@MBs combined with SPDT significantly reversed tumor hypoxia and inhibited tumor growth in 4T1-tumor bearing mice. This work presents a theragnostic system for reversing tumor hypoxia and enhancing TNBC treatment.

Bimetallic nanoplatform for synergistic sonodynamic-calcium overload therapy utilizing self-supplied hydrogen peroxide and relieved hypoxia

Sonodynamic therapy (SDT) has emerged as a potential alternative to traditional cancer treatments as it offers deep cellular penetration and reduced invasivity. Sonosensitizers generate reactive oxygen species (ROS) under ultrasound activation, focusing the ultrasound energy on malignant sites located deep in tissues and causing cell apoptosis and necrosis. However, due to tumor hypoxia and the limited levels of intracellular endogenous hydrogen peroxide (H2O2 is a fundamental species for supplying oxygen via catalase activity), SDT efficacy is still insufficient. In this study, a bimetallic and multifunctional system (Fe3O4-TAPP@PVP-CaO2) was prepared by using ferrosoferric oxide (Fe3O4) as a carrier loaded with 5,10,15,20-tetrakis(4-aminophenyl), porphyrin (TAPP), that was then coated with polyvinyl pyrrolidone (PVP) and calcium peroxide (CaO2). The CaO2 layer elevated the levels of H2O2 and Ca2+ in the tumor microenvironment when exposed to intracellular acidity, providing essential elements for oxygen generation. Intracellular hypoxia was alleviated via the catalase-like activity of Fe3O4 inducing calcium overload. Under ultrasonic irradiation, SDT generated toxic reactive oxygen species (ROS, singlet oxygen) and activated calcium influx through acoustic cavitation. Meanwhile, calcium overload therapy efficiently induced cell apoptosis at the moment of uncontrollable cellular accumulation of Ca2+. In addition, we modified the PVP on the surface to make it more stable. This study presents a bimetallic nanoplatform that can efficiently induce cancer cell death by synergistic sonodynamic-calcium overload therapy via modulation of O2/ROS/Ca2+ species, indicating its potential for multi-modality cancer therapy.

Effective Combination of Targeted Therapies with Sonodynamic Treatment for Use in Exploring Differences in Therapeutic Efficacy across Organelle Targets

Acoustic kinetic therapy systems that target specific organelles can improve the precision of a sonosensitizer, which is a perfect combination of targeted therapy and sonodynamic therapy (SDT) and plays an important role in current acoustic kinetic therapy. In this study, we loaded PpIX, a sonosensitizer, on targeted-functional carbon dots (CDs) via an amide reaction and then generated the mitochondria-targeted system (Mit-CDs-PpIX) and nucleus-targeted system (Nuc-CDs-PpIX), respectively, to deliver the sonosensitizer. Both systems exhibited minimal cytotoxicity in the absence of ultrasound stimulation. The efficacy of the targeted SDT systems was investigated using methylthiazol tetrazolium (MTT) assays, live/dead staining, flow cytometry, etc. Compared with the free PpIX and mitochondria-targeted system, the nucleus-targeted system is more potent in killing effect under ultrasound stimulation and induces apoptosis with higher intensity. To achieve the equal killing effect, the effective concentration of Nuc-CDs-PpIX is just one third of that of Mit-CDs-PpIX.

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.

Strategies to Reverse Hypoxic Tumor Microenvironment for Enhanced Sonodynamic Therapy

Sonodynamic therapy (SDT) has emerged as a highly effective modality for the treatment of malignant tumors owing to its powerful penetration ability, noninvasiveness, site-confined irradiation, and excellent therapeutic efficacy. However, the traditional SDT, which relies on oxygen availability, often fails to generate a satisfactory level of reactive oxygen species because of the widespread issue of hypoxia in the tumor microenvironment of solid tumors. To address this challenge, various approaches are developed to alleviate hypoxia and improve the efficiency of SDT. These strategies aim to either increase oxygen supply or prevent hypoxia exacerbation, thereby enhancing the effectiveness of SDT. In view of this, the current review provides an overview of these strategies and their underlying principles, focusing on the circulation of oxygen from consumption to external supply. The detailed research examples conducted using these strategies in combination with SDT are also discussed. Additionally, this review highlights the future prospects and challenges of the hypoxia-alleviated SDT, along with the key considerations for future clinical applications. These considerations include the development of efficient oxygen delivery systems, the accurate methods for hypoxia detection, and the exploration of combination therapies to optimize SDT outcomes.

A Multi-Layer Breast Cancer Model to Study the Synergistic Effect of Photochemotherapy

Breast cancer is one of the most common cancers among women. The development of new and effective therapeutic approaches in the treatment of breast cancer is an important challenge in modern oncology. Two-dimensional (2D) cell cultures are most often used in the study of compounds with potential anti-tumor nature. However, it is necessary to develop advanced three-dimensional (3D) cell models that can, to some extent, reflect the physiological conditions. The use of miniature cancer-on-a-chip microfluidic systems can help to mimic the complex cancer microenvironment. In this report, we developed a 3D breast cancer model in the form of a cell multilayer, composed of stromal cells (HMF) and breast cancer parenchyma (MCF-7). The developed cell model was successfully used to analyze the effectiveness of combined sequential photochemotherapy, based on doxorubicin and meso-tetraphenylporphyrin. We proved that the key factor that allows achieving the synergistic effect of combination therapy are the order of drug administration to the cells and the sequence of therapeutic procedures. To the best of our knowledge, studies on the effectiveness of combination photochemotherapy depending on the sequence of the component drugs were performed for the first time under microfluidic conditions on a 3D multilayered model of breast cancer tissue.

Fractionated Sonodynamic Therapy Using Gold@Poly(ortho-aminophenol) Nanoparticles and Multistep Low-Intensity Ultrasound Irradiation to Treat Melanoma Cancer: In Vitro and In Vivo Studies

OBJECTIVE

Cancer treatment using ultrasound irradiation with low intensities along with a sonosensitizer has been found to have significant advantages, such as high penetration depth in tissues, non-invasive therapeutic character, minor side effects, good patient adherence and preferential tumor area treatment. In the present study, gold nanoparticles covered by poly(ortho-aminophenol) (Au@POAP NPs) were synthesized and characterized as a new sonosensitizer.

METHODS

We investigated Au@POAP NPs efficacy on fractionated ultrasound irradiation for treatment of melanoma cancer in vitro as well as in vivo.

DISCUSSION

In vitro examinations revealed that although Au@POAP NPs (with a mean size of 9.8 nm) alone represented concentration-dependent cytotoxicity against the B16/F10 cell line, multistep ultrasound irradiation (1 MHz frequency, 1.0 W/cm² intensity, 60 s irradiation time) of the cells in the attendance of Au@POAP NPs led to efficient cell sonodynamic therapy (SDT) and death. Histological analyses revealed that in vivo fractionated SDT toward melanoma tumors of male balb/c mice led to no residual viable tumor cell after 10 d.

CONCLUSION

A deep sonosensitizing effectiveness of Au@POAP NPs on fractionated low-intensity ultrasound irradiation was attained with the main mechanism of tumor cell eradication of promotion of apoptosis or necrosis through dramatically increased reactive oxygen species levels.

Photodynamic therapy: Innovative approaches for antibacterial and anticancer treatments

Photodynamic therapy is an alternative treatment mainly for cancer but also for bacterial infections. This treatment dates back to 1900 when a German medical school graduate Oscar Raab found a photodynamic effect while doing research for his doctoral dissertation with Professor Hermann von Tappeiner. Unexpectedly, Raab revealed that the toxicity of acridine on paramecium depends on the intensity of light in his laboratory. Photodynamic therapy is therefore based on the administration of a photosensitizer with subsequent light irradiation within the absorption maxima of this substance followed by reactive oxygen species formation and finally cell death. Although this treatment is not a novelty, there is an endeavor for various modifications to the therapy. For example, selectivity and efficiency of the photosensitizer, as well as irradiation with various types of light sources are still being modified to improve final results of the photodynamic therapy. The main aim of this review is to summarize anticancer and antibacterial modifications, namely various compounds, approaches, and techniques, to enhance the effectiveness of photodynamic therapy.

Antitumor Effect of Photodynamic Therapy/Sonodynamic Therapy/Sono-Photodynamic Therapy of Chlorin e6 and Other Applications

Chlorin e6 (Ce6) has been extensively researched and developed as an antitumor therapy. Ce6 is a highly effective photosensitizer and sonosensitizer with promising future applications in photodynamic therapy, dynamic acoustic therapy, and combined acoustic and light therapy for tumors. Ce6 is also being studied for other applications in fluorescence navigation, antibacterials, and plant growth regulation. Here we review the role and research status of Ce6 in tumor therapy and the problems and challenges of its clinical application. Other biomedical effects of Ce6 are also briefly discussed. Despite the difficulties in clinical application, Ce6 has significant advantages in photodynamic therapy (PDT)/sonodynamic therapy (SDT) against cancer and offers several possibilities in clinical utility.

Emerging Sonodynamic Therapy-Based Nanomedicines for Cancer Immunotherapy

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

Enhanced Photodynamic Therapy: A Review of Combined Energy Sources

Photodynamic therapy (PDT) has been used in recent years as a non-invasive treatment for cancer, due to the side effects of traditional treatments such as surgery, radiotherapy, and chemotherapy. This therapeutic technique requires a photosensitizer, light energy, and oxygen to produce reactive oxygen species (ROS) which mediate cellular toxicity. PDT is a useful non-invasive therapy for cancer treatment, but it has some limitations that need to be overcome, such as low-light-penetration depths, non-targeting photosensitizers, and tumor hypoxia. This review focuses on the latest innovative strategies based on the synergistic use of other energy sources, such as non-visible radiation of the electromagnetic spectrum (microwaves, infrared, and X-rays), ultrasound, and electric/magnetic fields, to overcome PDT limitations and enhance the therapeutic effect of PDT. The main principles, mechanisms, and crucial elements of PDT are also addressed.

Newly developed gas-assisted sonodynamic therapy in cancer treatment

Sonodynamic therapy (SDT) is an emerging noninvasive treatment modality that utilizes low-frequency and low-intensity ultrasound (US) to trigger sensitizers to kill tumor cells with reactive oxygen species (ROS). Although SDT has attracted much attention for its properties including high tumor specificity and deep tissue penetration, its anticancer efficacy is still far from satisfactory. As a result, new strategies such as gas-assisted therapy have been proposed to further promote the effectiveness of SDT. In this review, the mechanisms of SDT and gas-assisted SDT are first summarized. Then, the applications of gas-assisted SDT for cancer therapy are introduced and categorized by gas types. Next, therapeutic systems for SDT that can realize real-time imaging are further presented. Finally, the challenges and perspectives of gas-assisted SDT for future clinical applications are discussed.

Enhanced mitochondria destruction on MCF-7 and HeLa cell lines in vitro using triphenyl-phosphonium-labelled phthalocyanines in ultrasound-assisted photodynamic therapy activity

This work reports on the reactive oxygen species (ROS) generation and the therapeutic activities of new triphenyl-phosphonium-labelled phthalocyanines (Pcs), the 2,9,16,23-tetrakis(N-(N-butyl-4-triphenyl-phosphonium)- pyridine-4-yloxy) Zn(II) Pc (3) and 2,9,16,23-tetrakis-(N-(N-butyl-4-triphenyl-phosphonium)-morpholino) Zn(II) Pc (4) upon exposure to light, ultrasound and the combination of light and ultrasound. Two types of ROS were detected: the singlet oxygen (¹O₂) and hydroxyl radicals. For light irradiations, only the ¹O₂ was detected. An increase in the ROS generation was observed for samples treated with the combination of light and ultrasound compared to the light and ultrasound mono-treatments. The in vitro anticancer activity through photodynamic (PDT) and sonodynamic (SDT) therapy for the Pcs were also determined and compared to the photo-sonodynamic combination therapy (PSDT). The two cancer cell lines used for the in vitro studies included the Michigan Cancer Foundation-7 (MCF-7) breast cancer and Henrietta Lacks (HeLa) cervical cancer cell lines. The SDT treatments showed improved therapeutic efficacy on the cancer cells for both the Pcs compared to PDT. PSDT showed better therapeutic efficacy compared to both the PDT and SDT mono-treatments.

The crosstalk between sonodynamic therapy and autophagy in cancer

As a noninvasive treatment approach for cancer and other diseases, sonodynamic therapy (SDT) has attracted extensive attention due to the deep penetration of ultrasound, good focusing, and selective irradiation sites. However, intrinsic limitations of traditional sonosensitizers hinder the widespread application of SDT. With the development of nanotechnology, nanoparticles as sonosensitizers or as a vehicle to deliver sonosensitizers have been designed and used to target tissues or tumor cells with high specificity and accuracy. Autophagy is a common metabolic alteration in both normal cells and tumor cells. When autophagy happens, a double-membrane autophagosome with sequestrated intracellular components is delivered and fused with lysosomes for degradation. Recycling these cell materials can promote survival under a variety of stress conditions. Numerous studies have revealed that both apoptosis and autophagy occur after SDT. This review summarizes recent progress in autophagy activation by SDT through multiple mechanisms in tumor therapies, drug resistance, and lipid catabolism. A promising tumor therapy, which combines SDT with autophagy inhibition using a nanoparticle delivering system, is presented and investigated.

Recent advances in mesoporous silica nanoparticle-based targeted drug-delivery systems for cancer therapy

Targeted drug-delivery systems are a growing research topic in tumor treatment. In recent years, mesoporous silica nanoparticles (MSNs) have been extensively studied and applied in noninvasive and biocompatible drug-delivery systems for tumor therapy due to their outstanding advantages, which include high surface area, large pore volume, tunable pore size, easy surface modification and stable framework. The advances in the application of MSNs for anticancer drug targeting are covered and highlighted in this review, and the challenges and prospects of MSN-based targeted drug-delivery systems are discussed. This review provides new insights for researchers interested in targeted drug-delivery systems against cancer.

Excited state and reactive oxygen species against cancer and pathogens: a review on sonodynamic and sono-photodynamic therapy

Photodynamic and sonodynamic therapy are therapies having great potential in the treatment of bacterial infections and cancer. Their background is associated with photo- and sonosensitizers - substances that can be excited when exposed to light or ultrasound. These sensitizers belong to a variety of compounds groups, including porphyrins, porphyrazines, and phthalocyanines. Releasing the energy when returning to the ground state can occur in the manner of transferring it to oxygen molecules, leading to reactive oxygen species able to disrupt membranes of bacterial and cancer cells, leaving the organism's cells unaffected. In recent years, the number of reports on numerous sensitizers being effective has been constantly growing. Therefore, the development of this field may prove beneficial for dealing with cancer and microbes. This review describes the development of photodynamic and sonodynamic therapy, as well as their combination, with emphasize on sonodynamic therapy and its potential in the treatment of cancer and bacterial infections.

Sonodynamic therapy: Rapid progress and new opportunities for non-invasive tumor cell killing with sound

Solid tumor treatment relies heavily upon chemotherapies, radiation, surgical resection, and/or immunotherapies. Although many alternative non-invasive solid tumor therapies have been proposed through the years and continue to be tested in various contexts, tumor cell eradication remains a daunting task for the current cancer armamentarium. Indeed, solid tumors exhibit physically and biochemically heterogenous microenvironments, allowing them to easily acquire resistance mechanisms. Progress in sonodynamic therapy (SDT), a treatment modality capable of controlling tumor growth while limiting off-target effects and toxicities, has accelerated in recent years. SDT combines "sonosensitizing" agents with the non-invasive application of focused acoustic energy [i.e. focused ultrasound (FUS)] to drive highly localized formation of tumor cell-killing reactive oxygen species (ROS). Sonosensitizers selectively accumulate in tumor cells, after which FUS radiation eliminates the tumor by forcing the tumor cells to undergo cell death. In this article, we comprehensively review recent studies wherein SDT has been applied to treat primary and metastatic tumors. We discuss sonosensitizers, combination therapies with SDT, developments in defining the mechanism of SDT-induced cell cytotoxicity, and the promise SDT offers as a modulator of anti-tumor immunity.

Smart nanocomposite assemblies for multimodal cancer theranostics

Despite great strides in anticancer research, performance statistics of current treatment modalities remain dismal, highlighting the need for safe, efficacious strategies for tumour mitigation. Non-invasive fusion technology platforms combining photodynamic, photothermal and hyperthermia therapies have emerged as alternate strategies with potential to meet many of the unmet clinical demands in the domain of cancer. These therapies make use of metallic and magnetic nanoparticles with light absorbing properties, which are manipulated to generate either reactive cytotoxic oxygen species or heat for tumour ablation. Combination therapies integrating light, heat and magnetism-mediated nanoplatforms with the conventional approaches of chemotherapy, radiotherapy and surgery are emerging as precision medicine for targeted interventions against cancer. This article aims to compile recent developments of advanced nanocomposite assemblies that integrate multimodal therapeutics for cancer treatment. Amalgamation of various effective, non-invasive technological platforms such as photodynamic therapy (PDT), photothermal therapy (PTT), magnetic hyperthermia (MHT), and chemodynamic therapy (CDT) have tremendous potential in presenting safe and efficacious solutions to the formidable challenges in cancer therapeutics.

Ultrasound-activated nanomaterials for sonodynamic cancer theranostics

Despite intensive efforts to develop diagnostic and therapeutic tools, the successful treatment of cancer is still hampered by the obscure boundary between cancerous cells and normal cells, recurrence of the cancer, and the development of drug resistance during chemotherapy. In recent years, sonodynamic therapy (SDT), employing therapeutic ultrasound with sonosensitizers, has attracted attention as a potentially promising approach for cancer therapy. This review describes the current understanding of the mechanisms and the preclinical and clinical efficacy of SDT-based applications in tumors, providing an insight into the therapeutic potential offered by SDT. The limitations and future directions of this emerging treatment are also discussed.

A Mitochondria-Localized Iridium(III)-Chlorin E6 Conjugate for Synergistic Sonodynamic and Two-Photon Photodynamic Therapy Against Melanoma

While melanoma in its early stages can be successfully treated, the prognosis strongly worsens with an increasing depth of the tumor. Capitalizing on this, there is an urgent need for...

A nanosensitizer self-assembled from oleanolic acid and chlorin e6 for synergistic chemo/sono-photodynamic cancer therapy

BACKGROUND

Sono-photodynamic therapy (SPDT) which is the combination of photodynamic therapy (PDT) and sonodynamic therapy (SDT), could exert much better anti-cancer effects than monotherapy. The combination of chemotherapy and PDT or SDT has shown great potential for cancer treatment. However, the combination of SPDT and chemotherapy for cancer treatment is rarely explored.

PURPOSE

We utilized a natural hydrophobic anti-cancer drug oleanolic acid (OA) and a photosensitizer chlorin e6 (Ce6) through self-assembly technology to form a carrier-free nanosensitizer OC for combined chemotherapy and SPDT for cancer treatment. No studies involving using carrier-free nanomedicine for combined chemotherapy/SPDT have been reported yet.

STUDY DESIGN

After fully characterization of OC, the in vitro and in vivo anti-cancer activities of OC were investigated and the mechanisms of the synergistic therapeutic effects were studied.

METHODS

OC were synthesized through self-assembly technology and characterized by dynamic light scattering (DLS) and an atomic force microscope (AFM). Confocal microscope was used to investigate the intracellular uptake efficiency and the penetration ability of OC. The cell viability of PC9 and 4T1 cells treated with OC under laser and ultrasound (US) irradiation was determined by MTT assay. Furthermore, flow cytometry was performed to detect the reactive oxygen species (ROS) generation, loss of mitochondrial membrane potential (MMP), cell apoptosis and cell cycle arrest. Finally, the anti-tumor therapeutic efficacy of OC was investigated in orthotopic 4T1 breast tumor-bearing mouse model.

RESULTS

OC showed an average particle size of around 100 nm with excellent light stability. OC increased more than 23 times accumulation of Ce6 in cancer cells and had strong tumor penetration ability in three-dimensional (3D) multicellular tumor spheroids (MCTSs). Compared with other therapeutic options, OC showed obvious synergistic inhibitory effects under light and US irradiation in PC9 and 4T1 cells with a significant decrease in IC₅₀ values. Mechanism studies showed that OC could generate high ROS, induce MMP loss, and cause apoptosis and cell cycle arrest. In vivo studies also approved the synergistic therapeutic effects of OC in 4T1 mouse models.

CONCLUSION

Self-assembled carrier-free nanosensitizer OC could be a promising therapeutic agent for synergistic chemo/sono-photodynamic therapy for cancer treatment.

Involvement of hydrogen peroxide in sonodynamical effect with sinoporphyrin sodium in hypoxic situation

Sonodynamic therapy (SDT) represents a noninvasive therapeutic method via the activation of certain chemical sensitizers using low intensity ultrasound to generate various reactive oxygen species (ROS). In this work, we conducted systematic experiments to evaluate the production of hydrogen peroxide (H₂O₂) in sinoporphyrin sodium (DVDMS) mediated SDT (DVDMS-SDT). We found that the fluorescence intensities of H₂O₂ specific probe BES-H₂O₂ and Amplex Red increased significantly exposure to DVDMS-SDT while decreased with the introduction of catalase (H₂O₂ scavenger), indicating the production of H₂O₂. And the fluorescence intensity of H₂O₂ susceptible probes were positively correlated with DVDMS concentration, ultrasound intensity and irradiation time. Under the same molarity concentration, DVDMS has advantages over proto-porphyrin IX (PpIX) and hemoporrin monomethyl ether (HMME) in H₂O₂ production, indicating that the yield of H₂O₂ depends on the properties of sensitizer. More importantly, DVDMS-SDT is involved in the process of H₂O₂ even in the oxygen-free condition, showing its greater superiority for the treatment of tumor under hypoxia environment.

Photo-sonodynamic combination activity of cationic morpholino-phthalocyanines conjugated to nitrogen and nitrogen-sulfur doped graphene quantum dots against MCF-7 breast cancer cell line in vitro

In this work, we explore the reactive oxygen species (ROS) generation abilities of cationic morpholino-substituted-phthalocyanine (Pc) conjugated to nitrogen (NGQDs) and nitrogen-sulfur (NSGQDs) doped-graphene quantum dots upon irradiation with light for photodynamic therapy (PDT), ultrasound for sonodynamic therapy (SDT) and the combination of both in photo-sonodynamic therapy (PSDT). The in vitro cytotoxicity studies were conducted using the Michigan Cancer Foundation-7 breast cancer cell lines (MCF-7 cells). For PDT treatments, only the ¹O₂ was detected for all the sensitizers, whereas both the ¹O₂ and ^•OH radicals were evident after SDT and PSDT treatments. An increase in the ¹O₂ generation was observed for the conjugates compared to the GQDs and the Pc alone. However, the ^•OH radicals were reduced in the conjugates compared to the GQDs and the Pc alone. The NGQDs generally showed better ROS generation efficacy compared to the NSGQDs, alone and in the conjugates. The combination therapy also shows improved efficacy compared to the monotherapies for the Pcs and Pc-GQDs conjugates.

Multiple-therapy strategies via polysaccharides-based nano-systems in fighting cancer

Polysaccharide-based biomaterials (e.g., chitosan, dextran, hyaluronic acid, chondroitin sulfate and heparin) have received great attention in healthcare, particularly in drug delivery for tumor therapy. They are naturally abundant and available, outstandingly biodegradable and biocompatible, and they generally have negligible toxicity and low immunogenicity. In addition, they are easily chemically or physically modified. Therefore, PSs-based nanoparticles (NPs) have been extensively investigated for the enhancement of tumor treatment. In this review, we introduce the synthetic pathways of amphiphilic PS derivatives, which allow the constructs to self-assemble into NPs with various structures. We especially offer an overview of the emerging applications of self-assembled PSs-based NPs in tumor chemotherapy, photothermal therapy (PTT), photodynamic therapy (PDT), gene therapy and immunotherapy. We believe that this review can provide criteria for a rational and molecular level-based design of PS-based NPs, and comprehensive insight into the potential of PS-based NPs used in multiple cancer therapies.

Recent progress in sono-photodynamic cancer therapy: From developed new sensitizers to nanotechnology-based efficacy-enhancing strategies

Many sensitizers have not only photodynamic effects, but also sonodynamic effects. Therefore, the combination of sonodynamic therapy (SDT) and photodynamic therapy (PDT) using sensitizers for sono-photodynamic therapy (SPDT) provides alternative opportunities for clinical cancer therapy. Although significant advances have been made in synthesizing new sensitizers for SPDT, few of them are successfully applied in clinical settings. The anti-tumor effects of the sensitizers are restricted by the lack of tumor-targeting specificity, incapability in deep intratumoral delivery, and the deteriorating tumor microenvironment. The application of nanotechnology-based drug delivery systems (NDDSs) can solve the above shortcomings, thereby improving the SPDT efficacy. This review summarizes various sensitizers as sono/photosensitizers that can be further used in SPDT, and describes different strategies for enhancing tumor treatment by NDDSs, such as overcoming biological barriers, improving tumor-targeted delivery and intratumoral delivery, providing stimuli-responsive controlled-release characteristics, stimulating anti-tumor immunity, increasing oxygen supply, employing different therapeutic modalities, and combining diagnosis and treatment. The challenges and prospects for further development of intelligent sensitizers and translational NDDSs for SPDT are also discussed.

Nanobubbles Containing sPD-1 and Ce6 Mediate Combination Immunotherapy and Suppress Hepatocellular Carcinoma in Mice

PURPOSE

Immune checkpoint inhibitors (ICIs) and sonodynamic therapy (SDT) are types of immunotherapy. In order to combine soluble programmed cell death protein 1 (sPD-1)-mediated immune checkpoint therapy and chlorin e6 (Ce6)-assisted SDT, nanobubbles (NBs) were generated to simultaneously load sPD-1 and Ce6.

MATERIALS AND METHODS

The sPD-1/Ce6-NBs, which were prepared by thin-film hydration and mechanical oscillation, had a stable physical condition, and delivered sPD-1 and Ce6 in a targeted manner. NBs could strengthen tumor suppression by increasing tumor-targeting accumulation of Ce6 and sPD-1, and by inducing ultrasound-targeted NB destruction. A mouse H22 cell hepatoma xenograft model was used to evaluate the synergetic immunotherapeutic effect and mechanism of sPD-1/Ce6-NBs.

RESULTS

By observing the tumor inhibition rate, tissue and cell apoptosis, apoptosis-related genes and protein expression, the best immunotherapeutic effect was exhibited by the sPD-1/Ce6-NBs group. The immunotherapeutic mechanism initially demonstrated that when tumor cells were transfected by sPD-1 delivered by NBs, which downregulated the expression of programmed death-ligand 1 (PD-L1) in tumor cells, and blocked the PD-1/PD-L1 signaling pathway, which improved T-cell-mediated tumor inhibition. Furthermore, ICIs combined with SDT induced immunogenic cell death by translocating calreticulin to the cell surface and then synergistically enhancing antitumor immune responses.

CONCLUSION

In conclusion, sPD-1/Ce6-NBs were successfully designed. Ultrasound-mediated sPD-1/Ce6-NBs are potentially effective delivery systems for combination immunotherapy of hepatocellular carcinoma.

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

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

Gadolinium-doped hollow silica nanospheres loaded with curcumin for magnetic resonance imaging-guided synergistic cancer sonodynamic-chemotherapy

Curcumin is a kind of anti-cancer chemotherapeutic drug and has been demonstrated to be able to produce reactive oxygen species (ROS) under the stimuli of ultrasound (US). Herein, gadolinium-doped hollow mesoporous silica nanospheres (Gd-HMSNs) loaded with curcumin (Cur) and conjugated with carboxymethyl dextran (CMD) have been facilely fabricated and applied for magnetic resonance imaging (MRI)-guided synergistic cancer sonodynamic-chemotherapy. The as-prepared multifunctional theranostic nanoplatform (Cur@Gd-HMSNs-CMD) shows high drug loading capacity, satisfactory biocompatibility, pH-responsive degradation, and US-triggered drug release. Due to the release of Gd³⁺ ions or oligomers during degradation, the nanoplatform Cur@Gd-HMSNs-CMD could serve as an effective contrast agent for T₁-weighted MRI to guide cancer treatment. More significantly, in vivo experiments show that the Cur@Gd-HMSNs-CMD can efficiently inhibit the tumor growth by a high inhibition rate of ~85.6% under US irradiation, mainly resulting from the synergistic effect of sonodynamic-chemotherapy. This innovative "two-in-one" theranostic nanoplatform using a single drug provides a new strategy for developing "all-in-one" nanomaterials for combined cancer treatment.

Photodynamic and Sonodynamic Therapy with Protoporphyrin IX: In Vitro and In Vivo Studies

Sono-photodynamic therapy is a promising anticancer technique based on the combination of sonodynamic and photodynamic therapy to improve the cancer treatment effectiveness. This study was aimed at analyzing the effects of the sono-photodynamic (SPD) activity on protoporphyrin IX (PpIX) solution and PpIX-loaded rat liver. In vitro, PpIX 5 μM solutions were irradiated with light (635 nm, 30-50 mW/cm²), ultrasound (1 MHz, 1-2 W/cm²) and both. The PpIX absorption spectra recorded over exposure time revealed that the PpIX decay rate induced by SPD activity (combined irradiation) was approximately the sum of those induced by photodynamic and sonodynamic activity. In vivo, rats were intraperitoneally injected with 5-aminolevulinic acid at the dose of 500 mg/kg weight. After 3 h of injection, the PpIX-loaded livers were irradiated with light (635 nm, 180 ± 9 J/cm²), ultrasound (1.0 MHz, 770 ± 40 J/cm²) and both using a single probe capable of illuminating and sonicating the liver simultaneously. After 30 h, the liver damage induced by each protocol was analyzed histologically. It was found that a greater necrosis depth was induced by the SPD activity. These results suggest that the SPD activity could improve the PpIX decay rate and have greater scope than photodynamic or sonodynamic activity. Further studies should be performed to gain a better understanding of this protocol.

Effect of ultrasonic frequency and power on the sonodynamic therapy activity of cationic Zn(II) phthalocyanines

We report on the sonodynamic activity of cationic phthalocyanines (Pcs) and the effect of the variation of two parameters: ultrasound frequency and power (Par I (1 MHz, 1 W cm^-2), Par II (1 MHz, 2 W cm^-2), Par III (3 MHz, 1 W cm^-2) and Par IV (3 MHz, 2 W cm^-2)) on the efficiency of their reactive oxygen species generation and cancer eradication in vitro thereof. Where Par stands for the various combinations of these parameters. Four Pcs were investigated with substituents bearing diethylamine, ortho- and para-pyridine and morpholine groups. Overall, the para-pyridine and morpholine Pcs showed substantial sono-activity in the various ultrasound parameters with Par I and IV generally showing better singlet oxygen and hydroxyl radicals generation confirmed by electron paramagnetic resonance spectroscopy. In some cases, very high hydroxyl radicals' generation was observed at Par II. Furthermore, the fragmentation of the Pcs after Par II treatments was confirmed using UV-vis and magnetic circular dichroism spectroscopy. The reactive species generation efficacy decreased at Par III for all samples. Ultrasound assisted cytotoxicity of the Pcs was confirmed in vitro using the human (Michigan Cancer Foundation-7) breast cancer cell line.

Recent advances in innovative strategies for enhanced cancer photodynamic therapy

Photodynamic therapy (PDT), a non-invasive therapeutic modality, has received increasing attention owing to its high selectivity and limited side effects. Although significant clinical research progress has been made in PDT, the breadth and depth of its clinical application have not been fully realized due to the limitations such as inadequate light penetration depth, non-targeting photosensitizers (PSs), and tumor hypoxia. Consequently, numerous investigations put their emphasis on innovative strategies to overcome the aforementioned limitations and enhance the therapeutic effect of PDT. Herein, up-to-date advances in these innovative methods for PDT are summarized by introducing the design of PS systems, their working mechanisms and application examples. In addition, current challenges of these innovative strategies for clinical application, and future perspectives on further improvement of PDT are also discussed.

Photosensitizer Nanoparticles Boost Photodynamic Therapy for Pancreatic Cancer Treatment

Patients with pancreatic cancer (PCa) have a poor prognosis apart from the few suitable for surgery. Photodynamic therapy (PDT) is a minimally invasive treatment modality whose efficacy and safety in treating unresectable localized PCa have been corroborated in clinic. Yet, it suffers from certain limitations during clinical exploitation, including insufficient photosensitizers (PSs) delivery, tumor-oxygenation dependency, and treatment escape of aggressive tumors. To overcome these obstacles, an increasing number of researchers are currently on a quest to develop photosensitizer nanoparticles (NPs) by the use of a variety of nanocarrier systems to improve cellular uptake and biodistribution of photosensitizers. Encapsulation of PSs with NPs endows them significantly higher accumulation within PCa tumors due to the increased solubility and stability in blood circulation. A number of approaches have been explored to produce NPs co-delivering multi-agents affording PDT-based synergistic therapies for improved response rates and durability of response after treatment. This review provides an overview of available data regarding the design, methodology, and oncological outcome of the innovative NPs-based PDT of PCa.

Recent Advances in Nanomaterial-Assisted Combinational Sonodynamic Cancer Therapy

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

Drug delivery systems based on CD44-targeted glycosaminoglycans for cancer therapy

The polysaccharide-based biomaterials hyaluronic acid (HA) and chondroitin sulfate (CS) have aroused great interest for use in drug delivery systems for tumor therapy, as they have outstanding biocompatibility and great targeting ability for cluster determinant 44 (CD44). In addition, modified HA and CS can self-assemble into micelles or micellar nanoparticles (NPs) for targeted drug delivery. This review discusses the formation of HA- and CS-based NPs, and various types of CS-based NPs including CS-drug conjugates, CS-polymer NPs, CS-small molecule NPs, polyelectrolyte nanocomplexes (PECs), CS-metal NPs, and nanogels. We then focus on the applications of HA- and CS-based NPs in tumor chemotherapy, gene therapy, photothermal therapy (PTT), photodynamic therapy (PDT), sonodynamic therapy (SDT), and immunotherapy. Finally, this review is expected to provide guidelines for the development of various HA- and CS-based NPs used in multiple cancer therapies.

Chlorin e6-loaded sonosensitive magnetic nanoliposomes conjugated with the magnetic field for enhancing anti-tumor effect of sonodynamic therapy

In sonodynamic therapy (SDT), when Chlorin e6 (Ce6) accumulates in tumor tissues, its anti-tumor effect can be achieved by ultrasound activation. To increase the local drug concentration of Ce6 in tumor cells, we had established a novel drug delivery system, Ce6-loaded sonosensitive magnetic nanoliposome (Ce6/SML), which realized the targeting delivery by the external magnetic field. It was worth mentioning that the targeting release of Ce6/SML and the activation on Ce6 could be achieved simultaneously by ultrasound of SDT. In our study, after Ce6 was loaded into the sonosensitive magnetic nanoliposome (SML), the values of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in vitro and in vivo were determined, indicating the activation on Ce6 of ultrasound. The delivery system also displayed the tumor-targeting ability and anti-tumor activity, which associated with the determined tumor growth and expression levels of angiogenin (ANG), vascular endothelial growth factor (VEGF) and tumor necrosis factor-alpha (TNF-α). In conclusion, the Ce6/SML-SDT-Targeted delivery system could effectively enhance the anti-tumor activity of SDT and had a great potential application for the treatment of malignant tumors located in deep tissues.

Rac1: A potential radiosensitization target of human nasopharyngeal carcinoma CNE2 cells

Radiotherapy has a high cure rate for early nasopharyngeal carcinoma(NPC). However, the radiation resistance of poorly differentiated NPC cells impacts the effectiveness of treatment of early-stage NPC patients. Here, we explored the relationship between Ras-related C3 botulinum toxin substrate 1(Rac1) expression and NPC radiosensitivity. In vitro and in vivo studies revealed that upregulation of Rac1, when combined with X-ray treatment, increased growth inhibition and induced remarkable morphological changes and apoptosis in CNE2 cells. Furthermore, rupturing of the cell and nuclear membranes, degeneration of the cristae and significant swelling of the mitochondria were observed, which were consistent with the high apoptotic rate. The Rac1(+) cells exhibited approximately 50% more migration compared with that of the NC and Rac1(-) cells. The overexpression of Rac1 can increase the radiation sensitivity of NPC CNE2 cells, and the mechanism may be closely related to the oxidative damage of mitochondria. Rac1 might be a potential target for radiosensitization in poorly differentiated NPC.

Curcumin-Loaded Poly(L-lactide-co-glycolide) Microbubble-Mediated Sono-photodynamic Therapy in Liver Cancer Cells

Sono-photodynamic therapy (SPDT) activates the same photo-/sonosensitizer and exerts more marked antitumor effects than sonodynamic therapy or photodynamic therapy. We aimed to explore the utilization of curcumin (CUR)-loaded poly(L-lactide-co-glycolide) microbubble (MB)-mediated SPDT (CUR-PLGA-MB-SPDT) in HepG2 liver cancer cells. The cytotoxicity and intracellular accumulation of CUR were determined. We used 40 µM CUR as the photo-/sonosensitizer for 3 h. In a comparison of CUR-SDT or CUR-PDT, HepG2 cell viability decreased and apoptotic rate increased in CUR-SPDT. The CUR-PLGA MBs had round spheres with smooth surfaces and an average size of 3.7 µm. In CUR-PLGA MBs, drug entrapment efficiency and drug-loading capacity were 74.29 ± 2.60% and 17.14 ± 0.60%, respectively. CUR-loaded PLGA MBs (CUR-PLGA MBs) had good biocompatibility with normal L02 cells and were almost non-cytotoxic to HepG2 cells. Among CUR-SDT, CUR-PDT, CUR-SPDT or CUR-PLGA-MB-SDT, the cell CUR-PLGA-MB-SPDT had the lowest viability. Transmission electron microscopy revealed pyroptosis and apoptosis in the CUR-PLGA-MB-SPDT group; the potential mechanism was related to the mitochondrial membrane potential loss and increased production of intracellular reactive oxygen species. These findings suggested that CUR-PLGA-MB-SPDT may be a promising treatment for liver cancer.

Therapeutic Effect of Doxorubicin-Chlorin E6-Loaded Mesoporous Silica Nanoparticles Combined with Ultrasound on Triple-Negative Breast Cancer

Introduction

Sonodynamic Therapy (SDT) has good targeting and non-invasive advantages in solid cancers, but its antitumor effect is not sufficient to replace traditional treatments. Some studies that combined SDT with chemotherapy or nanoparticles have managed to enhance its efficiency and overcome the side effects of chemotherapy.

Materials and Methods

In this study, we synthesized and characterized mesoporous silica nanoparticles (MSN-DOX-Ce6) loaded with doxorubicin (DOX) and sonosensitizer, chlorin e6 (Ce6). Then, we conducted in vitro and in vivo experiments to explore the antitumor effect of MSN-DOX-Ce6 under ultrasound (US) treatment.

Results

The characterization tests showed that the nanoparticles are uniformly sized spheres with mesoporous structure, resulting in a high drug-loading efficiency. In the in vitro experiments, MSN-DOX-Ce6 could effectively inhibit cell proliferation under US but not more than other treatment groups. However, the in vivo studies showed that MSN-DOX-Ce6+US has better antitumor effect than DOX+Ce6+US or DOX alone on xenograft tumor-bearing mice.

Conclusion

In summary, MSNs showed a great potential for DOX and Ce6 delivery. We concluded that under US, MSN-DOX-Ce6 nanocomposites increase the antitumor effect of DOX and SDT and thereby are a potential treatment for solid tumors.

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

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

Lipid and poly (ethylene glycol)-conjugated bi-functionalized chlorine e6 micelles for NIR-light induced photodynamic therapy

BACKGROUND

To develop a photosensitizer, chlorin e6 (Ce6)-based amphiphilic polymer, DP-Ce6, where DOPE and PEG are conjugated to Ce6, which would self-assemble to form polymeric micelles (DP-Ce6-M) in aqueous environment.

METHODS

DP-Ce6-M were characterized for particle size, zeta potential, and singlet oxygen (¹O₂) generation. Cellular internalization, phototoxicity were investigated against monolayer and 3D spheroids of human lung adenocarcinoma cells (A549).

RESULTS AND CONCLUSIONS

DP-Ce6-M formed stable micelles with particles size of 58.2 ± 1.6 nm. Solubility of Ce6 was improved. Photoactivity of DP-Ce6-M was sustained in regard to ¹O₂ generation compared to free Ce6. The DP-Ce6-M showed enhanced internalization and growth inhibition in monolayer and spheroidal cells. Overall, DP-Ce6-M demonstrated the potential for further exploration as PDT agent for cancer treatment.

The Destruction Of Laser-Induced Phase-Transition Nanoparticles Triggered By Low-Intensity Ultrasound: An Innovative Modality To Enhance The Immunological Treatment Of Ovarian Cancer Cells

Purpose

Photodynamic therapy (PDT), sonodynamic therapy (SDT), and oxaliplatin (OXP) can induce immunogenic cell death (ICD) following damage-associated molecular patterns (DAMPs) exposure or release and can be united via the use of nanoplatforms to deliver drugs that can impart anti-tumor effects. The aim of this study was to develop phase-transition nanoparticles (OI_NPs) loaded with perfluoropentane (PFP), indocyanine green (ICG), and oxaliplatin (OXP), to augment anti-tumor efficacy and the immunological effects of chemotherapy, photodynamic therapy and sonodynamic therapy (PSDT).

Methods

OI_NPs were fabricated by a double emulsion method and a range of physicochemical and dual-modal imaging features were characterized. Confocal microscopy and flow cytometry were used to determine the cellular uptake of OI_NPs by ID8 cells. The viability and apoptotic rate of ID8 cells were investigated using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay and flow cytometry. Flow cytometry, Western blotting, and luminometric assays were then used to investigate the exposure or release of crucial DAMPs such as calreticulin (CRT), high mobility group box 1 (HMGB1), and adenosine-5ʹ-triphosphate (ATP). Tumor rechallenge experiments were then used to investigate whether treated ID8 cells underwent ICD. Finally, cytotoxic T lymphocyte (CTL) activity was determined by a lactate dehydrogenase (LDH) assay.

Results

Spherical OI_NPs were able to carry OXP, ICG and PFP and were successfully internalized by ID8 cells. The application of OI_NPs significantly enhanced the phase shift ability of PFP and the optical characteristics of ICG, thus leading to a significant improvement in photoacoustic and ultrasonic imaging. When combined with near-infrared light and ultrasound, the application of OI_NPs led to improved anti-tumor effects on cancer cells, and significantly enhanced the expression of DAMPs, thus generating a long-term anti-tumor effect.

Conclusion

The application of OI_NPs, loaded with appropriate cargo, may represent a novel strategy with which to increase anti-tumor effects, enhance immunological potency, and improve dual-mode imaging.