Ultrasmall Oxygen-Deficient Bimetallic Oxide MnWOX Nanoparticles for Depletion of Endogenous GSH and Enhanced Sonodynamic Cancer Therapy

A Two-In-One Nanoprodrug for Photoacoustic Imaging-Guided Enhanced Sonodynamic Therapy

Sonodynamic therapy (SDT) is garnering considerable attention in cancer treatment due to its non-invasive nature and the potential of spatiotemporal control. However, the high level of glutathione (GSH) in cancer cells can alleviate the SDT-mediated ROS-damages, resulting in a reduced SDT effect. Here, a two-in-one nano-prodrug for photoacoustic imaging-guided enhanced SDT against skin cancers is synthesized. A dual-prodrug molecule (DOA) of sulfide dioxide (SO₂ ) and 5-aminolevulinic acid (ALA) is first synthesized and then co-assembled with methoxyl poly(ethylene glycol)-b-poly(l-lysine) (mPEG-b-PLL) to generate the two-in-one prodrug nanoparticles (P-DOA NPs). The P-DOA NPs simultaneously released ALA and SO₂ in response to the overexpressed GSH in tumor cells. The released ALA is metabolically converted into protoporphyrin IX (PpIX) in tumor cells for SDT and photoacoustic imaging. Meanwhile, the released SO₂ , together with the consumption of GSH based on the reaction of DOA in P-DOA NPs with intracellular GSH, can significantly increase the intracellular ROS content, leading to enhanced SDT. As a result, the P-DOA NPs significantly inhibited the growth of melanoma and squamous cell carcinoma xenografts in mouse models under the guidance of real-time photoacoustic imaging. Therefore, this novel two-in-one nano-prodrug is promising for effective SDT against skin cancers.

Tumor microenvironment regulation - enhanced radio - immunotherapy

Radiotherapy (RT) is frequently utilized for cancer treatment in clinical practice and has been proved to have immune stimulation potency in recent years. However, its inhibitory effect on tumor growth, especially on tumor metastasis, is still limited by many factors, including the complex tumor microenvironment (TME). Therefore, the TME - regulating SiO₂@MnO₂ nanoparticles (SM NPs) were prepared and applied to the combination of RT and immunotherapy. In a bilateral animal model, SM NPs not only enhanced the inhibitory effect of RT on primary tumor growth, but also strengthened the abscopal effect to inhibit the growth of distant untreated tumors. As for the distant untreated tumor, 40% of mice showed complete inhibition of tumor growth and 40% showed a suppressed tumor growth. Moreover, SM NPs showed modulation functions for TME through inducing the increase in intracellular levels of oxygen and reactive oxygen species after their reaction with hydrogen peroxide and the main antioxidative agent glutathione in TME. Lastly, SM NPs also effectively induced the increase in the amounts of cytokines secreted by macrophage - like cells, indicating modulation functions for immune responses. This work highlighted a potential strategy of simultaneously inhibiting tumor growth and metastasis through the regulation of TME and immune responses by SM NPs - enhanced radio - immunotherapy.

Piezotronic Effect-Augmented Cu2-xO-BaTiO3 Sonosensitizers for Multifunctional Cancer Dynamic Therapy

Ultrasound (US)-triggered sonodynamic therapy (SDT) based on semiconductor nanomaterials has attracted considerable attention for cancer therapy. However, most inorganic sonosensitizers suffer from low efficiency due to the rapid recombination of electron-hole pairs. Herein, the Cu_2-xO-BaTiO₃ piezoelectric heterostructure was fabricated as a sonosensitizer and chemodynamic agent, simultaneously, for improving reactive oxygen species (ROS) generation and cancer therapeutic outcome. Under US irradiation, the Cu_2-xO-BaTiO₃ heterojunction with a piezotronic effect exhibits high-performance singlet oxygen (¹O₂) and hydroxyl radical (•OH) generation to enhance SDT. Moreover, it possesses Fenton-like reaction activity to convert endogenous H₂O₂ into •OH for chemodynamic therapy (CDT). The integration of SDT and CDT substantially boosts ROS generation and cellular mitochondria damage, and the in vitro and in vivo results demonstrate high cytotoxicity and tumor inhibition on murine refractory breast cancer. This work realizes improvement in cancer therapy using piezoelectric heterostructures with piezotronic effects.

A MXene-derived redox homeostasis regulator perturbs the Nrf2 antioxidant program for reinforced sonodynamic therapy

Ultrasound (US)-mediated sonodynamic therapy (SDT) has emerged as a spatiotemporally controllable therapeutic modality in combating cancer because of its high tissue-penetration depth and minimal invasiveness. However, the elevated nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant program in cancer cells can serve as a chief reactive oxygen species (ROS) detoxification system to alleviate oxidative injury and promote tumorigenesis, and thus greatly antagonize the therapeutic efficacy of ROS-mediated anticancer therapies. Herein, we report that vanadium carbide MXene-derived carbon dots (PMQDs) can act as high-efficacy sonosensitizers to efficiently generate ROS upon US irradiation and simultaneously hinder the Nrf2 antioxidant program for enhanced sonodynamic therapy of cancer. These PMQDs show superior US-triggered ROS generating ability because of their efficient migration/separation of electron-hole pairs and narrow bandgap. Importantly, these PMQDs can serve as efficient redox homeostasis regulators to perturb the Nrf2 antioxidant mechanism and thus reduce its effects on ROS neutralization for enhanced SDT efficacy. Overall, the present study will not only provide a new paradigm to augment SDT by perturbing the Nrf2 antioxidant program, but also give valuable insights into developing high-efficacy MXene-derived nanoagents for cancer therapy.

Ultrathin-FeOOH-Coated MnO2 Sonosensitizers with Boosted Reactive Oxygen Species Yield and Remodeled Tumor Microenvironment for Efficient Cancer Therapy

Sonodynamic therapy (SDT) typically suffers from compromised anticancer efficacy owing to the low reactive oxygen species (ROS) yield and complicated tumor microenvironment (TME) which can consume ROS and support the occurrence and development of tumors. Herein, ultrathin-FeOOH-coated MnO2 nanospheres (denoted as MO@FHO) as sonosensitizers which can not only facilitate ultrasound (US)-triggered ROS but also tune the TME by hypoxia alleviation, H2 O2 consumption as well as glutathione (GSH) depletion are designed. The FeOOH coating will boost the production yield of singlet oxygen (1 O2 ) and hydroxyl radicals (• OH) by inhibiting the recombination of US-initiated electron-hole pairs and Fenton-like reaction, respectively. Additionally, the catalase-like and GSH peroxidase-like activities of MO@FHO nanospheres enable them to break the TME equilibrium via hypoxia alleviation and GSH depletion. The combination of high ROS yield and fundamental destruction of TME equilibrium results in satisfactory antitumor outcomes, as demonstrated by the high tumor suppression efficacy of MO@FHO on MDA-MB-231-tumor-bearing mice. No obvious toxicity is detected to normal tissues at therapeutic doses in vivo. The capability to modulate the ROS production and TME simultaneously can afford new probability for the development of advanced sonosensitizers for synergistic comprehensive cancer therapy.

Platinum–copper alloy nanoparticles armored with chloride ion transporter to promote electro-driven tumor inhibition

The induction of oxidative species, driven by oscillating electric field (E), has recently emerged as an effective approach for tumor inhibition, so-called electrodynamic therapy (EDT). While it offers a series of advantages attracting considerable attention, the fundamental mechanism and improvement strategies for EDT approach are being endeavored extensively with the aid of new material explorations. An interesting phenomenon observed in early studies is that the on-site concentration of chloride ion is highly favored for the induction of oxidative species and the efficacy of tumor inhibition. Following this discovery ignored previously, here for the first time, fine Pt/Cu alloy nanoparticles (PtCu₃ NPs) are integrated with chloride ion transporter (CIT) for EDT-based combinational therapy. In this system, while PtCu₃ NPs induce oxidative species under an electric field, it also effectively transforms endogenous H₂O₂ into •OH and consumes intracellular glutathione (GSH). More importantly, with the aid of CIT, PtCu₃-PEG@CIT NPs promote the intracellular concentration of chloride ion (Cl⁻) by transporting extracellular Cl⁻, facilitating the generation of oxidative species considerably. Meanwhile, CIT delivered intracellularly increases lysosomal pH, leading to the disruption of cellular autophagy and weakening the treatment resistance. In consequence, significant tumor inhibition is enabled both in vitro and in vivo, due to the combination of unique characteristics offered by PtCu₃-PEG@CIT.

•

PtCu₃-PEG NPs present the effective ROS generation under electric field and CDT activity.

•PtCu₃-PEG NPs could consume GSH, inhibiting ROS clearance to enhance EDT and CDT.

•PtCu₃-PEG@CIT NPs promote intercellular chloride ion concentration, facilitating the ROS generation under electric field.

•CIT disrupts autophagy, weakening tumor cell resistance to ROS induced by PtCu₃-PEG NPs.

Rigid metal/liquid metal nanoparticles: Synthesis and application for locally ablative therapy

Locally ablative therapy, as the main therapy for advanced tumors, has fallen into a bottleneck in recent years. The breakthrough of metal nanoparticles provides a novel approach for ablative therapy. Previous studies have mostly focused on the combined field of rigid metal nanoparticles and ablation. However, with the maturity of the preparation process of liquid metal nanoparticles, liquid metal nanoparticles not only have metallic properties but also have fluid properties, showing the potential to be combined with ablation. At present, there is no review on the combination of liquid metal nanoparticles and ablation. In this article, we first review the preparation, characterization and application characteristics of rigid metal and liquid metal nanoparticles in ablation applications, and then summarize the advantages, disadvantages and possible future development trends of rigid and liquid metal nanoparticles.

Minimally invasive nanomedicine: nanotechnology in photo-/ultrasound-/radiation-/magnetism-mediated therapy and imaging

Traditional treatments such as chemotherapy and surgery usually cause severe side effects and excruciating pain. The emergence of nanomedicines and minimally invasive therapies (MITs) has brought hope to patients with malignant diseases. Especially, minimally invasive nanomedicines (MINs), which combine the advantages of nanomedicines and MITs, can effectively target pathological cells/tissues/organs to improve the bioavailability of drugs, minimize side effects and achieve painless treatment with a small incision or no incision, thereby acquiring good therapeutic effects. In this review, we provide a comprehensive review of the research status and challenges of MINs, which generally refers to the medical applications of nanotechnology in photo-/ultrasound-/radiation-/magnetism-mediated therapy and imaging. Additionally, we also discuss their combined application in various fields including cancers, cardiovascular diseases, tissue engineering, neuro-functional diseases, and infectious diseases. The prospects, and potential bench-to-bedside translation of MINs are also presented in this review. We expect that this review can inspire the broad interest for a wide range of readers working in the fields of interdisciplinary subjects including (but not limited to) chemistry, nanomedicine, bioengineering, nanotechnology, materials science, pharmacology, and biomedicine.

A nanotheranostic agent based on Nd3+-doped YVO4 with blood-brain-barrier permeability for NIR-II fluorescence imaging/magnetic resonance imaging and boosted sonodynamic therapy of orthotopic glioma

The specific diagnosis and treatment of gliomas is a primary challenge in clinic due to their high invasiveness and blood-brain barrier (BBB) obstruction. It is highly desirable to find a multifunctional agent with good BBB penetration for precise theranostics. Herein, we design and construct a core-shell structured nanotheranostic agent (YVO₄:Nd³⁺-HMME@MnO₂-LF, marked as YHM) with YVO₄:Nd³⁺ particles as the core and MnO₂ nanosheets as the shell. Sonosensitizer hematoporphyrinmonomethyl ether (HMME) and lactoferrin (LF) were further loaded and modified on the surface, giving it a good ability to cross the BBB, near-infrared fluorescence imaging in the second window (NIR-II)/magnetic resonance imaging (MRI) bimodality, and highly efficient sonodynamic therapy (SDT) of orthotopic gliomas. The YVO₄:Nd³⁺ (25%) core exhibited good NIR-II fluorescence properties, enabling YHM to act as promising probes for NIR-II fluorescence imaging of vessels and orthotopic gliomas. MnO₂ shell can not only provide O₂ in the tumor microenvironments (TME) to significantly improve the healing efficacy of SDT, but also release Mn²⁺ ions to achieve T₁-weight MRI in situ. Non-invasive SDT can effectively restrain tumor growth. This work not only demonstrates that multifunctional YHM is promising for diagnosis and treatment of orthotopic glioma, but also provides insights into exploring the theranostic agents based on rare earth-doped yttrium vanadate nanoparticles.

Spiky Cascade Biocatalysts as Peroxisome-Mimics for Ultrasound-Augmented Tumor Ablation

Ultrasound (US)-augmented tumor ablation with sono-catalysts has emerged as a promising therapeutic modality due to high tissue penetration, nonionizing performance, and low cost of US-based therapies. Developing peroxisome-mimetic cascade biocatalysts for US-augmented synergistic treatment would further effectively reduce the dependence of the microenvironment H₂O₂ and enhance the tumor-localized reactive oxygen species (ROS) generation. Here, we proposed and synthesized a novel spiky cascade biocatalyst as peroxisome-mimics that consist of multiple enzyme-mimics, i.e., glucose oxidase-mimics (Au nanoparticles for producing H₂O₂) and heme-mimetic atomic catalytic centers (Fe-porphyrin for ROS generation), for US-augmented cascade-catalytic tumor therapy. The synthesized spiky cascade biocatalysts exhibit an obvious spiky structure, uniform nanoscale size, independent of endogenous H₂O₂, and efficient US-responsive biocatalytic activities. The enzyme-mimetic biocatalytic experiments show that the spiky cascade biocatalysts can generate abundant ·OH via a cascade chemodynamic path and also ¹O₂ via US excitation. Then, we demonstrate that the spiky cascade biocatalysts show highly efficient ROS production to promote melanoma cell apoptosis under US irradiation without extra H₂O₂. Our in vivo animal data further reveal that the proposed US-assisted chemodynamic cascade therapies can significantly augment the therapy efficacy of malignant melanoma. We suggest that these efficient peroxisome-mimetic cascade-catalytic strategies will be promising for clinical tumor therapies.

Ultrasound and nanomaterial: an efficient pair to fight cancer

Ultrasounds are often used in cancer treatment protocols, e.g. to collect tumor tissues in the right location using ultrasound-guided biopsy, to image the region of the tumor using more affordable and easier to use apparatus than MRI and CT, or to ablate tumor tissues using HIFU. The efficacy of these methods can be further improved by combining them with various nano-systems, thus enabling: (i) a better resolution of ultrasound imaging, allowing for example the visualization of angiogenic blood vessels, (ii) the specific tumor targeting of anti-tumor chemotherapeutic drugs or gases attached to or encapsulated in nano-systems and released in a controlled manner in the tumor under ultrasound application, (iii) tumor treatment at tumor site using more moderate heating temperatures than with HIFU. Furthermore, some nano-systems display adjustable sizes, i.e. nanobubbles can grow into micro-bubbles. Such dual size is advantageous since it enables gathering within the same unit the targeting properties of nano bubbles via EPR effect and the enhanced ultrasound contrasting properties of micro bubbles. Interestingly, the way in which nano-systems act against a tumor could in principle also be adjusted by accurately selecting the nano-system among a large choice and by tuning the values of the ultrasound parameters, which can lead, due to their mechanical nature, to specific effects such as cavitation that are usually not observed with purely electromagnetic waves and can potentially help destroying the tumor. This review highlights the clinical potential of these combined treatments that can improve the benefit/risk ratio of current cancer treatments.

Oxygen-Deficient BiOCl Combined with L-Buthionine-Sulfoximine Synergistically Suppresses Tumor Growth through Enhanced Singlet Oxygen Generation under Ultrasound Irradiation

Excess generation of reactive oxygen species (ROS) based on sensitizers under ultrasound (US) excitation can cause the death of tumor cells via oxidative damage, but sonosensitizers are largely unexplored. Herein, oxygen-deficient black BiOCl (B-BiOCl) nanoplates (NPs) are reported, with post-treatment on conventional BiOCl by simple UV excitation, showing stronger singlet oxygen (¹ O₂ ) generation than commercial TiO₂ nanoparticles and their derivatives under US irradiation. Moreover, L-buthionine-sulfoximine (BSO), a GSH biosynthesis inhibitor, is incorporated into B-BiOCl NPs. The authors find that BSO can be released owing to the degradation of B-BiOCl NPs in the presence of acid and GSH, which are overexpressed in tumors. The results show that BSO/B-BiOCl-PEG NPs have a multifunctional synergistic effect on improving ROS production. In particular, BiOCl has remarkable near-infrared light absorption after UV treatment and is good for photoacoustic imaging that can guide subsequent sonodynamic therapy. This work shows that just with a simple oxygen deficiency treatment, strong ¹ O₂ generation can be provided to a conventional material under US irradiation and, interestingly, this effect can be amplified by using a small inhibitor BSO, and this is clearly demonstrated in cell and mice experiments.

An Ultrasmall Fe3 O4 -Decorated Polydopamine Hybrid Nanozyme Enables Continuous Conversion of Oxygen into Toxic Hydroxyl Radical via GSH-Depleted Cascade Redox Reactions for Intensive Wound Disinfection

Nanozyme-based chemodynamic therapy (CDT) for fighting bacterial infections faces several major obstacles including low hydrogen peroxide (H₂ O₂ ) level, over-expressed glutathione (GSH) in infected sites, and inevitable damage to healthy tissue with abundant nonlocalized nanozymes. Herein, a smart ultrasmall Fe₃ O₄ -decorated polydopamine (PDA/Fe₃ O₄ ) hybrid nanozyme is demonstrated that continuously converts oxygen into highly toxic hydroxyl radical (•OH) via GSH-depleted cascade redox reactions for CDT-mediated bacterial elimination and intensive wound disinfection. In this system, photonic hyperthermia of PDA/Fe₃ O₄ nanozymes can not only directly damage bacteria, but also improve the horseradish peroxidase-like activity of Fe₃ O₄ decorated for CDT. Surprisingly, through photothermal-enhanced cascade catalytic reactions, PDA/Fe₃ O₄ nanozymes can consume endogenous GSH for disrupting cellular redox homeostasis and simultaneously provide abundant H₂ O₂ for improving •OH generation, ultimately enhancing the antibacterial performance of CDT. Such PDA/Fe₃ O₄ can bind with bacterial cells, and reveals excellent antibacterial property against both Staphylococcus aureus and Escherichia coli. Most interestingly, PDA/Fe₃ O₄ nanozymes can be strongly retained in infected sites by an external magnet for localized long-term in vivo CDT and show minimal toxicity to healthy tissues and organs. This work presents an effective strategy to magnetically retain the therapeutic nanozymes in infected sites for highly efficient CDT with good biosafety.

On-demand assembly of polymeric nanoparticles for longer-blood-circulation and disassembly in tumor for boosting sonodynamic therapy

Sonodynamic therapy (SDT) is one of the promising strategies for tumor therapy, but its application is usually hindered by fast clearance in blood-circulation, abnormal tumor microenvironment, and inefficient generation of reactive oxygen species. To solve these problems, we proposed an on-demand assembly-disassembly strategy, where the assembly is favorable for longer-blood-circulation and then the disassembly in tumor is favorable for boosting SDT. Hematoporphyrin monomethyl ether (HMME) as the model of organic sonosensitizers were conjugated with hyaluronic acid (HA). Then HA-HMME was mixed with catalase (CAT) and assembled into polymeric nanoparticles (CAT@HA-HMME NPs) with size of ∼80 nm. CAT@HA-HMME NPs exhibit good biocompatibility and a longer blood half-time (t_1/2 = 4.17 h) which is obviously longer than that (∼0.82 h) of HMME molecules. After HA receptor-mediated endocytosis of cancer cells, CAT@HA-HMME NPs can be cleaved by endogenous hyaluronidase, resulting in the on-demand disassembly in tumor to release HA-HMME molecules and CAT. The CAT catalyzes the endogenous H₂O₂ into O₂ to relieve the hypoxic microenvironment, and the released HA-HMME exhibits a higher ROS generation ability, greatly boosting SDT for the inhibition of tumor growth. Therefore, the on-demand assembly-disassembly strategy may provide some insight in the design and development of nanoagents for tumor therapy.

•

On-demand assembly from molecules to nanoparticles for longer-blood-circulation.

•

On-demand disassembly in presence of hyaluronidase (in tumor) for boosting sonodynamic effects.

•

Efficient damage on cancer cells in-vitro and Significant inhibition of the tumor growth due to the enhanced SDT.

Biomimetic nanoprobe-augmented triple therapy with photothermal, sonodynamic and checkpoint blockade inhibits tumor growth and metastasis

Background

Comprehensive antitumor therapy through integrated multimodal means has drawn increasing attention owing to its high efficiency and metastasis suppression.

Results

We describe a synergistic triple protocol combining photothermal and sonodynamic therapy (PTT and SDT), together with immune checkpoint blockade for the inhibition of breast cancer growth and metastases in the 4T1 mouse model. PTT and SDT are synergistically augmented by a novel multimodal imaging nanoprobe integrated with cancer cell membrane-biomimetic nanoparticles (CHINPs) loaded with superparamagnetic iron oxide (SPIO) and hematoporphyrin monomethyl ether (HMME). CHINPs exhibit excellent homologous tumor targeting, and are sequentially triggered by ultrasound and near infrared (NIR) light under the guidance of magnetic resonance, photoacoustic and photothermal imaging, leading to complete in situ tumor eradication and systemic anti-tumor immune activation. Further combination of this approach with immune checkpoint blockade therapy is shown to suppress tumor metastasis.

Conclusion

This work provides proof-of-principle for triple therapy using multimodal imaging-guided PTT/SDT based on biomimetic nanoprobes in combination with immunotherapy to eliminate tumors.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01287-y.

Tumor microenvironment-responsive fenton nanocatalysts for intensified anticancer treatment

Chemodynamic therapy (CDT) based on Fenton or Fenton-like reactions is an emerging cancer treatment that can both effectively fight cancer and reduce side effects on normal cells and tissues, and it has made important progress in cancer treatment. The catalytic efficiency of Fenton nanocatalysts(F-NCs) directly determines the anticancer effect of CDT. To learn more about this new type of therapy, this review summarizes the recent development of F-NCs that are responsive to tumor microenvironment (TME), and detailedly introduces their material design and action mechanism. Based on the deficiencies of them, some effective strategies to significantly improve the anticancer efficacy of F-NCs are highlighted, which mainly includes increasing the temperature and hydrogen peroxide concentration, reducing the pH, glutathione (GSH) content, and the dependence of F-NCs on acidic environment in the TME. It also discusses the differences between the effect of multi-mode therapy with external energy (light and ultrasound) and the single-mode therapy of CDT. Finally, the challenges encountered in the treatment process, the future development direction of F-NCs, and some suggestions are analyzed to promote CDT to enter the clinical stage in the near future.

Stimuli-Responsive Nanoparticles for Controlled Drug Delivery in Synergistic Cancer Immunotherapy

Cancer immunotherapy has achieved promising clinical progress over the recent years for its potential to treat metastatic tumors and inhibit their recurrences effectively. However, low patient response rates and dose-limiting toxicity remain as major dilemmas for immunotherapy. Stimuli-responsive nanoparticles (srNPs) combined with immunotherapy offer the possibility to amplify anti-tumor immune responses, where the weak acidity, high concentration of glutathione, overexpressions of enzymes, and reactive oxygen species, and external stimuli in tumors act as triggers for controlled drug release. This review highlights the design of srNPs based on tumor microenvironment and/or external stimuli to combine with different anti-tumor drugs, especially the immunoregulatory agents, which eventually realize synergistic immunotherapy of malignant primary or metastatic tumors and acquire a long-term immune memory to prevent tumor recurrence. The authors hope that this review can provide theoretical guidance for the construction and clinical transformation of smart srNPs for controlled drug delivery in synergistic cancer immunotherapy.

Photosynthetic Oxygenation-Augmented Sonodynamic Nanotherapy of Hypoxic Tumors

Reactive oxygen species (ROS) has been employed as a powerful therapeutic agent for eradicating tumor via oxidative stress. As an emerging ROS-involving noninvasive anticancer therapeutic modality, sonodynamic therapy (SDT) with high tissue penetration depth and benign remote spatiotemporal selectivity has been progressively utilized as the distinct alternative for ROS-based tumor treatment. However, the hypoxic tumor microenvironment substantially restricts the sonodynamic effect. In this work, an oxygen self-sufficient hybrid sonosensitizer on the basis of photosynthetic microorganisms cyanobacteria (Cyan) integrated with ultrasmall oxygen-deficient bimetallic oxide Mn_1.4 WO_x nanosonosensitizers, termed as M@C, is designed and engineered to overcome the critical issue of hypoxia-induced tumor resistance and strengthen the SDT effect. The sustained photosynthetic oxygen production by Cyan under light illumination can promote Mn_1.4 WO_x nanosonosensitizers to produce more ROS against cancer cells both in vitro and in vivo under ultrasound (US) irradiation. Especially, the sustained oxygen evolution for suppressing the gene expression of hypoxia-inducible factor 1alpha (HIF-1α) further boosts and augments the SDT efficiency. Thus, this work provides the paradigm that the rationally engineered biohybrid microorganism-based multifunctional sonosensitizers can serve as an effective bioplatform for augmenting the therapeutic efficiency of SDT, particularly for the treatment of hypoxic tumors.

Enhancing Penetration Ability of Semiconducting Polymer Nanoparticles for Sonodynamic Therapy of Large Solid Tumor

Sonodynamic therapy (SDT) holds growing promise in deep-seated or large solid tumor treatment owing to its high tissue penetration depth ability; however, its therapeutic efficacy is often compromised due to the hypopermeable and hypoxic characteristics in the tumor milieu. Herein, a semiconducting polymer nanoparticle (SPNC) that synergistically enhances tumor penetration and alleviates tumor hypoxia is reported for sonodynamic therapy of large solid tumors. SPNC comprises a semiconducting polymer nanoparticle core as a sonodynamic converter coated with a poly (ethylene glycol) corona. An oxygen-modulating enzyme, catalase, is efficiently conjugated to the surface of nanoparticles via the coupling reaction. Superior to its counterpart SPNCs (SPNC2 (84 nm) and SPNC3 (134 nm)), SPNC with the smallest size (SPNC1 (35 nm)) can efficiently penetrate throughout the tumor interstitium to alleviate whole tumor hypoxia in a large solid tumor model. Upon ultrasound (US) irradiation, SPNC1 can remotely generate sufficient singlet oxygen to eradicate tumor cells at a deep-tissue depth. Such a single treatment of SPNC1-medicated sonodynamic therapy effectively inhibits tumor growth in a large solid tumor mouse model. Therefore, this study provides a generalized strategy to synergistically overcome both poor penetration and hypoxia of large tumors for enhanced cancer treatment.

Platinum Crosslinked Carbon Dot@TiO2-x p-n Junctions for Relapse-Free Sonodynamic Tumor Eradication via High-Yield ROS and GSH Depletion

Sonodynamic therapy as a promising noninvasive modality is being developed for tumor therapy, but there is a lack of next-generation sonosensitizers that can generate full ROS at high yields and simultaneously deplete elevated levels of glutathione (GSH) in tumor cells. Semiconductor p-n junctions are engineered as high-efficacy sonosensitizers for sonodynamic tumor eradication using pyridine N-doped carbon dots (N-CDs) as a p-type semiconductor and oxygen-deficient TiO_2-x nanosheets as a n-type semiconductor. The rate constants of ¹ O₂ and •OH generation by ultrasound-excited N-CD@TiO_2-x p-n junctions are 4.3 and 4.5 times higher than those of TiO₂ , respectively. A Z-scheme carrier migration mechanism in the p-n junction achieving the rapid spatial separation of the ultrasound-generated electron-hole pairs for enhanced full ROS production is proposed. GSH-cleavable, Pt-crosslinked, N-doped CD fluorescent probes to detect the presence of intracellular GSH are also constructed. A GSH-responsive, p-n junction platform (Pt/N-CD@TiO_2-x ) with integrated GSH detection, GSH depletion, and enhanced sonodynamic performance is then assembled. Malignant tumors are completely eradicated without relapse via intravenous administration of low-dose Pt/N-CD@TiO_2-x under ultrasound irradiation. This work substantiates the great potential of biocompatible, GSH-responsive p-n junctions as next-generation sonosensitizers via p-n junction-enhanced ROS generation and metal ion oxidation of intracellular GSH.

In-situ TiO2-x decoration of titanium carbide MXene for photo/sono-responsive antitumor theranostics

BACKGROUND

Sonodynamic therapy (SDT) has emerged as a noninvasive therapeutic modality that involves sonosensitizers and low-intensity ultrasound. However, owing to the rapid recombination of charge carriers, most of the sonosensitizers triggered poor reactive oxygen species (ROS) generation, resulting in unsatisfactory sonodynamic therapeutic effects.

RESULTS

Herein, a photo/sono-responsive nanoplatform was developed through the in-situ systhesis of TiO2-x on the surface of two-dimensional MXene (titanium carbide, Ti3C2) for photoacoustic/photothermal bimodal imaging-guided near-infrared II (NIR-II) photothermal enhanced SDT of tumor. Because of several oxygen vacancies and smaller size (~ 10 nm), the in-situ formed TiO2-x nanoparticles possessed narrow band gap (2.65 eV) and high surface area, and thus served as a charge trap to restrict charge recombination under ultrasound (US) activation, resulting in enhanced sonodynamic ROS generation. Moreover, Ti3C2 nanosheets induced extensive localized hyperthermia relieves tumor hypoxia by accelerating intratumoral blood flow and tumor oxygenation, and thus further strengthened the efficacy of SDT. Upon US/NIR-II laser dual-stimuli, Ti3C2@TiO2-x nanoplatform triggered substantial cellular killing in vitro and complete tumor eradication in vivo, without any tumor recurrence and systemic toxicity.

CONCLUSION

Our work presents the promising design of photo/sono-responsive nanoplatform for cancer nanotheranostics.

Aggregation-Enhanced Sonodynamic Activity of Phthalocyanine-Artesunate Conjugates

The clinical prospect of sonodynamic therapy (SDT) has not been fully realized due to the scarcity of efficient sonosensitizers. Herein, we designed phthalocyanine-artesunate conjugates (e.g. ZnPcT4 A), which could generate up to ca. 10-fold more reactive oxygen species (ROS) than the known sonosensitizer protoporphyrin IX. Meanwhile, an interesting and significant finding of aggregation-enhanced sonodynamic activity (AESA) was observed for the first time. ZnPcT4 A showed about 60-fold higher sonodynamic ROS generation in the aggregated form than in the disaggregated form in aqueous solutions. That could be attributed to the boosted ultrasonic cavitation of nanostructures. The level of the AESA effect depended on the aggregation ability of sonosensitizer molecules and the particle size of their aggregates. Moreover, biological studies demonstrated that ZnPcT4 A had high anticancer activities and biosafety. This study thus opens up a new avenue the development of efficient organic sonosensitizers.

A Cascade Nanozyme with Amplified Sonodynamic Therapeutic Effects through Comodulation of Hypoxia and Immunosuppression against Cancer

The tumor microenvironment (TME) featured by immunosuppression and hypoxia is pivotal to cancer deterioration and metastasis. Thus, regulating the TME to improve cancer cell ablation efficiency has received extensive interest in oncotherapy. However, to reverse the immunosuppression and alleviate hypoxia simultaneously in the TME are major challenges for effective cancer therapy. Herein, a multifunctional platform based on Au nanoparticles and a carbon dots modified hollow black TiO₂ nanosphere (HABT-C) with intrinsic cascade enzyme mimetic activities is prepared for reversing immunosuppression and alleviating hypoxia in the TME. The HABT-C NPs possess triple-enzyme mimetic activity to act as self-cascade nanozymes, which produce sufficient oxygen to alleviate hypoxia and generate abundant ROS. The theoretical analysis demonstrates that black TiO₂ facilitates absorption of H₂O and O₂, separation of electron-holes, and generation of ROS, consequently amplifying the sonodynamic therapy (SDT) efficiency. Specifically, HABT-C exhibits favorable inhibition of immunosuppressive mediator expression, along with infiltrating of immune effector cells into the TME and reversing the immunosuppression in the TME. As a result, HABT-C can effectively kill tumor cells via eliciting immune infiltration, alleviating hypoxia, and improving SDT efficiency. This cascade nanozyme-based platform (HABT-C@HA) will provide a strategy for highly efficient SDT against cancer by modulation of hypoxia and immunosuppression in the TME.

Engineering Nanoplatform for Combined Cancer Therapeutics via Complementary Autophagy Inhibition

Despite advances in the development of tumor treatments, mortality from cancer continues to increase. Nanotechnology is expected to provide an innovative anti-cancer therapy, to combat challenges such as multidrug resistance and tumor recurrence. Nevertheless, tumors can greatly rely on autophagy as an alternative source for metabolites, and which desensitizes cancer cells to therapeutic stress, hindering the success of any current treatment paradigm. Autophagy is a conserved process by which cells turn over their own constituents to maintain cellular homeostasis. The multistep autophagic pathway provides potentially druggable targets to inhibit pro-survival autophagy under various therapeutic stimuli. In this review, we focus on autophagy inhibition based on functional nanoplatforms, which may be a potential strategy to increase therapeutic sensitivity in combinational cancer therapies, including chemotherapy, radiotherapy, phototherapy, sonodynamic therapy, and immunotherapy.

Tumor redox microenvironment modulating composite hydrogels for enhanced sonodynamic therapy of colorectal cancer

Effective treatment of colorectal cancer is important to improve the quality of life for patients, which however remains a great challenge in the clinic. Herein, we report the construction of...

Ferroptosis promotes sonodynamic therapy: a platinum(ii)–indocyanine sonosensitizer

Sonodynamic therapy (SDT) has unique advantages in deep tumour ablation due to its deep penetration depth, showing great preclinical and clinical potential. Herein, a platinum(ii)–cyanine complex has been designed to investigate its potential as a SDT anticancer agent. It generates singlet oxygen (¹O₂) under ultrasound (US) irradiation or light irradiation, and exhibits US-cytotoxicity in breast cancer 4T1 cells but with negligible dark-cytotoxicity. Mechanistic investigations reveal that Pt-Cy reduces the cellular GSH and GPX4, and triggers cancer cell ferroptosis under US irradiation. The metabolomics analysis illustrates that Pt-Cy upon US treatment significantly dysregulates glutathione metabolism, and finally induces ferroptosis. In vivo studies further demonstrate that Pt-Cy inhibits tumor growth under US irradiation and its efficiency for SDT is better than that for PDT in vivo. This is the first example of platinum(ii) complexes for sonodynamic therapy. This work extends the biological applications of metal complexes from PDT to SDT.

A novel platinum(ii)–cyanine complex showed a greater excellent sonodynamic therapeutic effect than photodynamic therapy in vivo. This work expands the biological applications of metal complexes from traditional photodynamic therapy to sonodynamic therapy.

Dynamic Ligand Screening by Magnetic Nanoassembly Modulates Stem Cell Differentiation

In native microenvironment, diverse physical barriers exist to dynamically modulate stem cell recruitment and differentiation for tissue repair. In this study, nanoassembly-based magnetic screens of various sizes are utilized, and they are elastically tethered over an RGD ligand (cell-adhesive motif)-presenting material surface to generate various nanogaps between the screens and the RGDs without modulating the RGD density. Large screens exhibiting low RGD distribution stimulate integrin clustering to facilitate focal adhesion, mechanotransduction, and differentiation of stem cells, which are not observed with small screens. Magnetic downward pulling of the large screens decreases the nanogaps, which dynamically suppress the focal adhesion, mechanotransduction, and differentiation of stem cells. Conversely, magnetic upward pulling of the small screens increases the nanogaps, which dynamically activates focal adhesion, mechanotransduction, and differentiation of stem cells. This regulation mechanism is also shown to be effective in the microenvironment in vivo. Further diversifying the geometries of the physical screens can further enable diverse modalities of multifaceted and safe unscreening of the distributed RGDs to unravel and modulate stem cell differentiation for tissue repair.

Ultra-small bimetallic phosphide for dual-modal MRI imaging guided photothermal ablation of tumor

Metal phosphides have been proved to be the potential theranostic agents of tumor. However, the limitation of single-modal imaging or treatment effect of such materials need to be further improved....

Metal-Organic Framework (MOF)-Based Ultrasound-Responsive Dual-Sonosensitizer Nanoplatform for Hypoxic Cancer Therapy

Sonodynamic therapy (SDT), which uses reactive oxygen species to target tumors, has shown promise in the management of unresectable cancers. However, the hypoxic tumor environment limits SDT efficiency, making complete tumor destruction challenging. Here, a dual-sonosensitizer nanoplatform is developed by loading an alkyl radical generator (2,2-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, AIPH) onto a zirconium metal-organic framework (Zr-MOF). The Zr-MOF@AIPH nanoparticles (NPs) can produce singlet oxygen, which can kill tumor cells under normoxic conditions, as well as alkyl radicals, which can kill tumor cells under both normoxic and hypoxic conditions. The combination of these free radicals further enhances SDT efficiency. Meanwhile, the nitrogen generated owing to AIPH decomposition can reduce the cavitation threshold and enhance the acoustic cavitation effect, thereby promoting NP penetration at the tumor site. Moreover, Zr-MOF@AIPH NPs exhibit good photoacoustic, fluorescence, and ultrasound imaging abilities due to their porphyrin-based structure and the nitrogen generated, which can remotely control NP delivery and determine the optimal therapeutic time window, ensuring the maximization of SDT efficiency. In vitro and in vivo examinations prove the superior antitumor efficacy, excellent biocompatibility, and favorable imaging ability of Zr-MOF@AIPH. This study spearheads the charge toward improving SDT efficacy in hypoxic environments via a combination of complementary sonosensitizers.

Tumor-Microenvironment-Activated Reactive Oxygen Species Amplifier for Enzymatic Cascade Cancer Starvation/Chemodynamic /Immunotherapy

At present, some progress has been made in the field of cancer theranostics based on nanocatalysts (NCs), but achieving precise theranostics in response to the specific tumor microenvironment (TME) remains a major challenge. Herein, a TME-responsive upconversion nanoparticles (UCNPs)-based smart UCNPs@Cu-Cys-GOx (UCCG) nanosystem is engineered, which combines natural enzymes and nanozymes so as to amplify reactive oxygen species (ROS) generation in situ for cancer starvation/chemodynamic/immunotherapy. One of the biggest merits of this material is that it can be preserved inert (off) in normal tissues, and only in the TME can it be specifically activated (on) through a series of enzymatic cascades to boost ROS production via a strategy of open source (H₂ O₂ self-supplying ability) and reduce expenditure (glutathione (GSH) consuming ability). More importantly, the enhanced oxidative stress by UCCG NCs reverses the immunosuppressive TME, and facilitates antitumor immune responses. Meanwhile, the starvation/chemodynamic synergistic therapy triggered by UCCG combined with PD-L1 antibody effectively inhibits the growth of primary tumors and cancer metastasis. In addition, the UCNPs in UCCG present upconversion luminescence enhancement, which can be exploited to visualize the reinforced ROS generation in real time. Collectively, this work provides an original method for the devising and exploitation of UCNPs-based catalytic immunotherapy.

Nanocatalyst-Mediated Chemodynamic Tumor Therapy

Traditional tumor treatments, including chemotherapy, radiotherapy, photodynamic therapy, and photothermal therapy, are developed and used to treat different types of cancer. Recently, chemodynamic therapy (CDT) has been emerged as a novel cancer therapeutic strategy. CDT utilizes Fenton or Fenton-like reaction to generate highly cytotoxic hydroxyl radicals (•OH) from endogenous hydrogen peroxide (H₂ O₂ ) to kill cancer cells, which displays promising therapeutic potentials for tumor treatment. However, the low catalytic efficiency and off-target side effects of Fenton reaction limit the biomedical application of CDT. In this regard, various strategies are implemented to potentiate CDT against tumor, including retrofitting the tumor microenvironment (e.g., increasing H₂ O₂ level, decreasing reductive substances, and reducing pH), enhancing the catalytic efficiency of nanocatalysts, and other strategies. This review aims to summarize the development of CDT and summarize these recent progresses of nanocatalyst-mediated CDT for antitumor application. The future development trend and challenges of CDT are also discussed.

Harnessing in situ glutathione for effective ROS generation and tumor suppression via nanohybrid-mediated catabolism dynamic therapy

The overexpression of glutathione (GSH) in cancer cells has long been regarded as the primary obstacle for reactive oxygen species (ROS)-involved anti-tumor therapies. To solve this issue, a ferric ion and selenite-codoped calcium phosphate (Fe/Se-CaP) nanohybrid here is fabricated to catabolize endogenous GSH, instead of directly deleting it, to trigger a ROS storm for tumor suppression. The selenite component in Fe/Se-CaP can catabolize GSH to superoxide anion (O₂^•-) and hydroxyl radicals (•OH) via cascade catalytic reactions, elevating oxidative stress while destroying antioxidant system. The doped Fe can further catalyze the soaring hydrogen peroxide (H₂O₂) originated from O₂^•- to •OH via Fenton reactions. Collectively, Fe/Se-CaP mediated self-augmented catabolism dynamic therapy finally induces apoptosis of cancer cells owing to the significant rise of ROS and, combined with CaP adjuvant, evokes adaptive immune responses to suppress tumor progression, providing an innovative train of thought for ROS-involved anti-tumor therapies.

A novel hypocrellin-based assembly for sonodynamic therapy against glioblastoma

The non-invasive treatment of glioblastoma (GBM) is of great significance and can greatly reduce the complications of craniotomy. Sonodynamic therapy (SDT) is an emerging tumor therapeutic strategy that overcomes some fatal flaws of photodynamic therapy (PDT). Different from PDT, SDT has deep tissue penetration and can be applied in the non-invasive treatment of deep-seated tumors. However, effective sonosensitizers that can be used for SDT of GBM are still very rare. Herein, we have prepared a suitable assembly based on a hypocrellin derivative (CTHB) with good biocompatibility. Excitedly, the hypocrellin-based assembly (CTHB NPs) can effectively produce reactive oxygen species under ultrasound stimulation. The inherent fluorescence and photoacoustic imaging characteristics of the CTHB NPs are conducive to the precise positioning of the tumors. It has been proved both in subcutaneous and in intracranial tumor models that CTHB NPs can be used as an effective sonosensitizer to inhibit tumor growth under ultrasound irradiation. This hypocrellin-based assembly has a good clinical prospect in the non-invasive treatment of GBM.

Sonodynamic therapy: Ultrasound parameters and in vitro experimental configurations

Sonodynamic therapy (SDT) is a new therapeutic modality for noninvasive cancer treatment based on the association of ultrasound and sonosensitizer drugs. Up to date, there is not a consensus on the standardization of the experimental conditions for the in vitro studies to correctly assess cell viability during SDT. Therefore, this review article mainly describes how the main ultrasound parameters and experimental setups of ultrasound application in vitro studies can influence the SDT bioeffects/response. The sonodynamic action is impacted by the combination of frequency, intensity, duty cycle, and ultrasound application time. The variation of experimental setups in cell culture, such as the transducer position, cell-transducer distance, coupling medium thickness, or type of culture, also influences the sonodynamic response. The intensity, duty cycle, and sonication duration increase cytotoxicity and reactive oxygen species production. For similar ultrasound parameters, differences in the experimental configuration impact cell death in vitro. Four main experimental setups are used to assess for SDT in cell culture (i) a planar transducer placed directly in contact with the bottom of the culture microplate; (ii) microplate positioned in the transducer's far-field using a water tank; (iii) sealed cell culture tubes immersed in water away from the transducer; and (iv) transducer dipped directly into the well with cell culture. Because of the significant variations in the experimental setups, sonodynamic response can significantly vary, and the translation of these results for in vivo experimentation is difficult. Therefore, a well-designed and detailed in vitro experimental setup is vital for understanding the interactions among the biological medium, the sonosensitizer, and the ultrasound for the in vitro to in vivo translation in SDT.

Biodegradable reduce expenditure bioreactor for augmented sonodynamic therapy via regulating tumor hypoxia and inducing pro-death autophagy

BACKGROUNDS

Sonodynamic therapy (SDT) as an emerging reactive oxygen species (ROS)-mediated antitumor strategy is challenged by the rapid depletion of oxygen, as well as the hypoxic tumor microenvironment. Instead of the presently available coping strategies that amplify the endogenous O2 level, we have proposed a biodegradable O2 economizer to reduce expenditure for augmenting SDT efficacy in the present study.

RESULTS

We successfully fabricated the O2 economizer (HMME@HMONs-3BP-PEG, HHBP) via conjugation of respiration inhibitor 3-bromopyruvate (3BP) with hollow mesoporous organosilica nanoparticles (HMONs), followed by the loading of organic sonosensitizers (hematoporphyrin monomethyl ether; HMME) and further surface modification of poly(ethylene glycol) (PEG). The engineered HHBP features controllable pH/GSH/US-sensitive drug release. The exposed 3BP could effectively inhibit cell respiration for restraining the oxygen consumption, which could alleviate the tumor hypoxia conditions. More interestingly, it could exorbitantly elevate the autophagy level, which in turn induced excessive activation of autophagy for promoting the therapeutic efficacy. As a result, when accompanied with suppressing O2-consumption and triggering pro-death autophagy strategy, the HHBP could achieve the remarkable antitumor activity, which was systematically validated both in vivo and in vitro assays.

CONCLUSIONS

This work not only provides a reduce expenditure means for enduring SDT, but also represents an inquisitive strategy for tumor treatments by inducing pro-death autophagy.

Sonodynamic Therapy with Metal Complexes: A New Promise in Cancer Therapy

In recent years, to overcome the problem of low tissue penetration power of light in photodynamic therapy (PDT), sonodynamic therapy (SDT) with ultrasound (US) as the drug stimulus has emerged as a potential alternative to PDT. The significantly higher tissue penetration capacity of US is reported to allow the treatment of deep-seated tumours. In general, organic molecules and nanomaterials dominate as the sonosensitizers in this area of research, and the potential of metal complexes in SDT is not yet well explored. In this highlight, we have summarized two recent literature reports in which researchers have explored the efficiency of metal complexes as sonosensitizers for the first time. These reports indicate the high potential of metal complexes in SDT.

2D Piezoelectric Bi2 MoO6 Nanoribbons for GSH-Enhanced Sonodynamic Therapy

Reducing the scavenging capacity of reactive oxygen species (ROS) and elevating ROS production are two primary goals of developing novel sonosensitizers for sonodynamic therapy (SDT). Hence, ultrathin 2D Bi2 MoO6 -poly(ethylene glycol) nanoribbons (BMO NRs) are designed as piezoelectric sonosensitizers for glutathione (GSH)-enhanced SDT. In cancer cells, BMO NRs can consume endogenous GSH to disrupt redox homeostasis, and the GSH-activated BMO NRs (GBMO) exhibit an oxygen-deficient structure, which can promote the separation of electron-hole pairs, thereby enhancing the efficiency of ROS production in SDT. The ultrathin GBMO NRs are piezoelectric, in which ultrasonic waves introduce mechanical strain to the nanoribbons, resulting in piezoelectric polarization and band tilting, thus accelerating toxic ROS production. The as-synthesized BMO NRs enable excellent computed tomography imaging of tumors and significant tumor suppression in vitro and in vivo. A piezoelectric Bi2 MoO6 sonosensitizer-mediated two-step enhancement SDT process, which is activated by endogenous GSH and amplified by exogenous ultrasound, is proposed. This process not only provides new options for improving SDT but also broadens the application of 2D piezoelectric materials as sonosensitizers in SDT.

Dual-Depletion of Intratumoral Lactate and ATP with Radicals Generation for Cascade Metabolic-Chemodynamic Therapy

Increasing evidence has demonstrated that lactate and adenosine triphosphate (ATP) both play important roles in regulating abnormal metabolism in the tumor microenvironment. Herein, an O2 self-supplying catalytic nanoagent, based on tannic acid (TA)-Fe(III) coordination complexes-coated perfluorooctyl bromide (PFOB) nanodroplets with lactate oxidases (LOX) loading (PFOB@TA-Fe(III)-LOX, PTFL), is designed for cascade metabolic-chemodynamic therapy (CDT) by dual-depletion of lactate and ATP with hydroxyl • OH radicals generation. Benefiting from the catalytic property of loaded LOX and O2 self-supplying of PFOB nanodroplets, PTFL nanoparticles (NPs) efficiently deplete tumoral lactate for down-regulation of vascular endothelial growth factor expression and supplement the insufficient endogenous H2 O2 . Simultaneously, TA-Fe(III) complexes release Fe(III) ions and TA in response to intracellular up-regulated ATP in tumor cells followed by TA-mediated Fe(III)/Fe(II) conversion, leading to the depletion of energy source ATP and the generation of cytotoxic • OH radicals from H2 O2 . Moreover, TA-Fe(III) complexes provide photoacoustic contrast as imaging guidance to enhance therapeutic accuracy. As a result, PTFL NPs efficiently accumulate in tumors for suppression of tumor growth and show evidence of anti-angiogenesis and anti-metastasis effects. This multifunctional nanoagent may provide new insight for targeting abnormal tumor metabolism with the combination of CDT to achieve a synergistic therapeutic effect.

Perfluorocarbon loaded fluorinated covalent organic polymers with effective sonosensitization and tumor hypoxia relief enable synergistic sonodynamic-immunotherapy

Relieving tumor hypoxia has recently been found to be a promising approach to reverse tumor immunosuppression and thus enhance the treatment outcomes of diverse cancer treatments. Herein, we prepared a type of fluorinated covalent conjugate polymers (COPs) with sonosensitizer meso-5, 10, 15, 20-tetra (4-hydroxylphenyl) porphyrin (THPP) and perfluorosebacic acid (PFSEA) as cross-linkers, yielding THPP_pf-COPs with efficient sonodynamic efficacy and loading capacity towards perfluoro-15-crown-5-ether (PFCE), a model perfluorocarbon molecule. Upon intratumoral injection, such PFCE@THPP_pf-COPs could not only attenuate tumor hypoxia, but also exhibit the most effective suppression effect on tumor growth in the presence of ultrasound exposure by inducing immunogenic cell death of cancer cells. Furthermore, we found that the sonodynamic therapy of PFCE@THPP_pf-COPs together with anti-CD47 immunotherapy would synergistically suppress tumor growth by increasing the tumor-infiltrating frequencies of phagocytic M1 macrophages and cytotoxic CD3⁺CD8⁺ T cells, while reducing the frequency of immunosuppressive regulatory T cells. Moreover, such combination treatment could also elicit potent protective memory antitumor immunity to prevent tumor challenge. Therefore, this work presents PFCE@THPP_pf-COPs are a type of multifunctional nano-sonosensitizers potent in removing negative impacts of inherent tumor hypoxia and immunosuppression, and suppressing tumor growth and tumor recurrence by priming host's antitumor immunity, particularly in synergizing with anti-CD47 immunotherapy.

Exosome-mediated delivery of inflammation-responsive Il-10 mRNA for controlled atherosclerosis treatment

Rationale: Tailored inflammation control is badly needed for the treatment of kinds of inflammatory diseases, such as atherosclerosis. IL-10 is a potent anti-inflammatory cytokine, while systemic and repeated delivery could cause detrimental side-effects due to immune repression. In this study, we have developed a nano-system to deliver inflammation-responsive Il-10 mRNA preferentially into macrophages for tailored inflammation control. Methods: Il-10 was engineered to harbor a modified HCV-IRES (hepatitis C virus internal ribosome entry site), in which the two miR-122 recognition sites were replaced by two miR-155 recognition sites. The translational responsiveness of the engineered mRNA to miR-155 was tested by Western blot or ELISA. Moreover, the engineered Il-10 mRNA was passively encapsulated into exosomes by forced expression in donor cells. Therapeutic effects on atherosclerosis and the systemic leaky expression effects in vivo of the functionalized exosomes were analyzed in ApoE^-/- (Apolipoprotein E-deficient) mice. Results: The engineered IRES-Il-10 mRNA could be translationally activated in cells when miR-155 was forced expressed or in M1 polarized macrophages with endogenous miR-155 induced. In addition, the engineered IRES-Il-10 mRNA, when encapsulated into the exosomes, could be efficiently delivered into macrophages and some other cell types in the plaque in ApoE^-/- mice. In the recipient cells of the plaque, the encapsulated Il-10 mRNA was functionally translated into protein, with relatively low leaky in other tissues/organs without obvious inflammation. Consistent with the robust Il-10 induction in the plaque, exosome-based delivery of the engineered Il-10 could alleviate the atherosclerosis in ApoE^-/- mice. Conclusion: Our study established a potent platform for controlled inflammation control via exosome-based systemic and repeated delivery of engineered Il-10 mRNA, which could be a promising strategy for atherosclerosis treatment.

Multifunctional Composite Nanosystems for Precise/Enhanced Sonodynamic Oxidative Tumor Treatment

Ultrasound-activated therapies have been regarded as the efficient strategy for tumor treatment, among which sonosensitizer-enabled sonodynamic oxidative tumor therapy features intrinsic advantages as compared to other exogenous trigger-activated dynamic therapies. Nanomedicine-based nanosonosensitizer design has been extensively explored for improving the therapeutic efficacy of sonodynamic therapy (SDT) of tumor. This review focuses on solving two specific issues, i.e., precise and enhanced sonodynamic oxidative tumor treatment, by rationally designing and engineering multifunctional composite nanosonosensitizers. This multifunctional design can augment the therapeutic efficacy of SDT against tumor by either improving the production of reactive oxygen species or inducing the synergistic effect of SDT-based combinatorial therapies. Especially, this multifunctional design is also capable of endowing the nanosonosensitizer with bioimaging functionality, which can effectively guide and monitor the therapeutic procedure of the introduced sonodynamic oxidative tumor treatment. The design principles, underlying material chemistry for constructing multifunctional composite nanosonosensitizers, intrinsic synergistic mechanism, and bioimaging guided/monitored precise SDT are summarized and discussed in detail with the most representative paradigms. Finally, the existing critical issues, available challenges, and potential future developments of this research area are also discussed for promoting the further clinical translations of these multifunctional composite nanosonosensitizers in SDT-based tumor treatment.