Dual-Cascade Activatable Nanopotentiators Reshaping Adenosine Metabolism for Sono-Chemodynamic-Immunotherapy of Deep Tumors

Tumor Microenvironment Activated Cu Crosslinked Near-Infrared Sonosensitizers for Visualized Cuproptosis-Enhanced Sonodynamic Cancer Immunotherapy

Reactive oxygen species (ROS)-mediated sonodynamic therapy (SDT) holds increasing potential in treating deep-seated tumor owing to the high tissue-penetration depth. However, the inevitable accumulation of sonosensitizers in normal tissues not only make it difficult to realize the in situ SDT, but also induces sonodynamic effects in normal tissues. Herein, this work reports the passivation and selective activation strategies for the sonodynamic and near-infrared (NIR) imaging performances of an intelligent antitumor theranostic platform termed Cu-IR783 nanoparticles (NPs). Owing to the ruptured coordination bond between IR783 with Cu ions by responding to tumor microenvironment (TME), the selective activation of IR783 only occurred in tumor tissues to achieve the visualized in-situ SDT. The tumor-specific released Cu ions not only realized the cascade amplification of ROS generation through Cu+-mediated Fenton-like reaction, but also triggered cuproptosis through Cu+-induced DLAT oligomerization and mitochondrial dysfunction. More importantly, the immunosuppressive TME can be reversed by the greatly enhanced ROS levels and high-efficiency cuproptosis, ultimately inducing immunogenic cell death that promotes robust systemic immune responses for the eradication of primary tumors and suppression of distant tumors. This work provides a distinct paradigm of the integration of SDT, CDT, and cuproptosis in a controlled manner to achieve visualized in-situ antitumor therapy.

Nanomedicine for combination of chemodynamic therapy and immunotherapy of cancers

Chemodynamic therapy (CDT), as a new type of therapy, has received more and more attention in the field of tumor therapy in recent years. By virtue of the characteristics of weak acidity and excess H2O2 in the tumor microenvironment, CDT uses the Fenton or Fenton-like reactions to catalyze the transformation of H2O2 into strongly oxidizing ˙OH, resulting in increased intracellular oxidative stress for lipid oxidation, protein inactivation, or DNA damage, and finally inducing apoptosis of cancer cells. In particular, CDT has the advantage of tumor specificity. However, the therapeutic efficacy of CDT frequently depends on the catalytic efficiency of the Fenton reaction, which needs the presence of sufficient H2O2 and catalytic metal ions. Relatively low concentrations of H2O2 and the lack of catalytic metal ions usually limit the final therapeutic effect. The combination of CDT with immunotherapy will be an effective means to improve the therapeutic effect. In this review paper, the recent progress related to nanomedicine for the combination of CDT and immunotherapy is summarized. Immunogenic death of tumor cells, immune checkpoint inhibitors, and stimulator of interferon gene (STING) activation as the main immunotherapy strategies to combine with CDT are discussed. Finally, the challenges and prospects for the clinical translation and future development direction are discussed.

Tumor microenvironment-responsive manganese-based nano-modulator activate the cGAS-STING pathway to enhance innate immune system response

BACKGROUND

Manganese ions (Mn2+) combined with adjuvants capable of damaging and lysing tumor cells form an antitumor nano-modulator that enhances the immune efficacy of cancer therapy through the cascade activation of the cyclic GMP-AMP interferon gene synthase-stimulator (cGAS-STING) pathway, which underscores the importance of developing antitumor nano-modulators, which induce DNA damage and augment cGAS-STING activity, as a critical future research direction. METHODS AND RESULTS: We have successfully synthesized an antitumor nano-modulator, which exhibits good dispersibility and biosafety. This nano-modulator is engineered by loading manganese dioxide nanosheets (M-NS) with zebularine (Zeb), known for its immunogenicity-enhancing effects, and conducting targeted surface modification using hyaluronic acid (HA). After systemic circulation to the tumor site, Mn2+, Zeb, and reactive oxygen species (ROS) are catalytically released in the tumor microenvironment by H+ and H2O2. These components can directly or indirectly damage the DNA or mitochondria of tumor cells, thereby inducing programmed cell death. Furthermore, they promote the accumulation of double-stranded DNA (dsDNA) in the cytoplasm, enhancing the activation of the cGAS-STING signalling pathway and boosting the production of type I interferon and the secretion of pro-inflammatory cytokines. Additionally, Zeb@MH-NS enhances the maturation of dendritic cells, the infiltration of cytotoxic T lymphocytes, and the recruitment of natural killer cells at the tumor site.

CONCLUSIONS

This HA-modified manganese-based hybrid nano-regulator can enhance antitumor therapy by boosting innate immune activity and may provide new directions for immunotherapy and clinical translation in cancer.

Progress of Nanomaterials Based on Manganese Dioxide in the Field of Tumor Diagnosis and Therapy

As a pivotal transition metal oxide, manganese dioxide (MnO2) has garnered significant attention owing to its abundant reserves, diverse crystal structures and exceptional performance. Nanosizing MnO2 results in smaller particle sizes, larger specific surface areas, optimized material characteristics, and expanded application possibilities. With the burgeoning research efforts in this field, MnO2 has emerged as a promising nanomaterial for tumor diagnosis and therapy. The distinctive properties of MnO2 in regulating the tumor microenvironment (TME) have attracted considerable interest, leading to a rapid growth in research on MnO2-based nanomaterials for tumor diagnosis and treatment. Additionally, MnO2 nanomaterials are also gradually showing up in the regulation of chronic inflammatory diseases. In this review, we mainly summarized the recent advancements in various MnO2 nanomaterials for tumor diagnosis and therapy. Furthermore, we discuss the current challenges and future directions in the development of MnO2 nanomaterials, while also envisaging their potential for clinical translation.

Copper Single-Atom-Based Metal-Organic Framework for Ultrasound-Enhanced Nanocatalytic Therapy

Chemodynamic therapy (CDT) is an emerging therapeutic modality triggered by endogenous substances in the tumor microenvironment (TME) to generate reactive oxygen species. However, the mild acid pH, low H2O2 concentration, and overexpressed glutathione can suppress the CDT efficiency. Herein, ultrasound (US)-triggered Cu2+-based single-atom nanoenzymes (FA-NH2-UiO-66-Cu, FNUC) are constructed with the performance of target and glutathione depletion. In the TME, the single-atom Cu sites of FNUC consume glutathione and the FNUC:Cu+ generates •OH via peroxidase-like activity. The US-activated FNUC exhibits a fast •OH generation rate, a low Michaelis constant, and a large •OH concentration, indicating the cavitation effect of US promotes the •OH generation. Meanwhile, the tumor target of FNUC is confirmed by NIR-II fluorescence imaging, in which it is modified with IR-1061. Combined with the antitumor performance of FNUC in vitro and in vivo, the novel Cu-based SAzymes can achieve efficient and precise cancer treatment.

Oxygen-carrying semiconducting polymer nanoprodrugs induce sono-pyroptosis for deep-tissue tumor treatment

Sonodynamic therapy (SDT) has been explored for cancer therapy, especially for deep tumors due to its low tissue penetration restriction. The therapeutic efficacy of SDT is limited due to the complicated tumor microenvironment. This study reports the construction of oxygen-carrying semiconducting polymer nanoprodrugs (OSPNpro) for deep tumor treatment via combining amplified SDT with pyroptosis. An oxygen carrier perfluorohexane, sonodynamic semiconducting polymer as the sonosensitizer, and reactive oxygen species (ROS)-responsive prodrug are co-loaded into a nanoparticle system, leading to the formation of these polymer nanoprodrugs. Such OSPNpro show an effective accumulation in tumor tissues after systemic administration, in which they deliver oxygen to relieve tumor hypoxia microenvironment and thus mediate amplified SDT via producing ROS under ultrasound (US) irradiation, even when the tumors are covered with a 2-cm chicken breast tissue. In addition, the ROS-responsive prodrugs are activated by the generated ROS to trigger pyroptosis of tumor cells. Such a sono-pyroptosis induces a strong antitumor immunity with obviously higher level infiltrations of effector immune cells into tumors. Therefore, OSPNpro-based combinational therapy can greatly inhibit the growth of 2-cm chicken breast tissue-covered deep tumors and suppress tumor metastasis. This study offers a prodrug nanoplatform for treatment of deep tumor via sono-pyroptosis strategy.

Engineering Sonosensitizer-Derived Nanotheranostics for Augmented Sonodynamic Therapy

Sonodynamic therapy (SDT), featuring noninvasive, deeper penetration, low cost, and repeatability, is a promising therapy approach for deep-seated tumors. However, the general or only utilization of SDT shows low efficiency and unsatisfactory treatment outcomes due to the complicated tumor microenvironment (TME) and SDT process. To circumvent the issues, three feasible approaches for enhancing SDT-based therapeutic effects, including sonosensitizer optimization, strategies for conquering hypoxia TME, and combinational therapy are summarized, with a particular focus on the combination therapy of SDT with other therapy modalities, including chemodynamic therapy, photodynamic therapy, photothermal therapy, chemotherapy, starvation therapy, gas therapy, and immunotherapy. In the end, the current challenges in SDT-based therapy on tumors are discussed and feasible approaches for enhanced therapeutic effects are provided. It is envisioned that this review will provide new insight into the strategic design of high-efficiency sonosensitizer-derived nanotheranostics, thereby augmenting SDT and accelerating the potential clinical transformation.

Facile synthesis of a hydrazone-based zinc(ii) complex for ferroptosis-augmented sonodynamic therapy

Sonodynamic therapy (SDT), as a novel non-invasive cancer treatment modality derived from photodynamic therapy (PDT), has drawn much attention due to its unique advantages for the treatment of deep tumors. Zinc-based complexes have shown great clinical prospect in PDT due to their excellent photodynamic activity and biosafety. However, their application in SDT has lagged seriously behind. Exploring efficient zinc-based complexes as sono-sensitizers remains an appealing but significantly challenging task. Herein, we develop a hydrazone ligand-based zinc complex (ZnAMTC) for SDT of tumors in vitro and in vivo. ZnAMTC was facilely synthesized via a two-step reaction from low-cost raw materials without tedious purification. It shows negligible dark toxicity and can produce singlet oxygen (1O2) under ultrasound (US) irradiation, exhibiting high sono-cytotoxicity to various cancer cells. Mechanism studies show that ZnAMTC can effectively reduce the levels of glutathione (GSH) and glutathione peroxidase 4 (GPX4) under US irradiation and later cause ferroptosis of cancer cells. In vivo studies further demonstrate that ZnAMTC exhibits efficient tumor growth inhibition under US irradiation and has good biosafety. This work provides useful insights into the design of first-row transition metal complexes for SDT application.

PAD4 Inhibitor-Functionalized Layered Double Hydroxide Nanosheets for Synergistic Sonodynamic Therapy/Immunotherapy Of Tumor Metastasis

Sonodynamic therapy (SDT) is demonstrated to trigger the systemic immune response of the organism and facilitate the treatment of metastatic tumors. However, SDT-mediated neutrophil extracellular traps (NETs) formation can promote tumor cell spread, thus weakening the therapeutic effectiveness of metastatic tumors. Herein, the amorphous CoW-layered double hydroxide (a-CoW-LDH) nanosheets are functionalized with a peptidyl arginine deiminase 4 (PAD4) inhibitor, i.e., YW3-56, to construct a multifunctional nanoagent (a-LDH@356) for synergistic SDT/immunotherapy. Specifically, a-CoW-LDH nanosheets can act as a sonosensitizer to generate abundant reactive oxygen species (ROS) under US irradiation. After loading with YW3-56, a-LDH@356 plus US irradiation not only effectively induces ROS generation and immunogenic cell death, but also inhibits the elevation of citrullinated histone H3 (H3cit) and the release of NETs, enabling a synergistic enhancement of anti-tumor metastasis effect. Using 4T1 tumor model, it is demonstrated that combining a-CoW-LDH with YW3-56 stimulates an anti-tumor response by upregulating the proportion of immune-activated cells and inducing polarization of M1 macrophages, and inhibits immune escape by downregulating the expression of PD-1 on immune cells under US irradiation, which not only arrests primary tumor progression with a tumor inhibition rate of 69.5% but also prevents tumor metastasis with the least number of lung metastatic nodules.

Iron-Based Metal-Organic Frameworks as Multiple Cascade Synergistic Therapeutic Effect Nano-Drug Delivery Systems for Effective Tumor Elimination

Efforts have been made to improve the therapeutic efficiency of tumor treatments, and metal-organic frameworks (MOFs) have shown excellent potential in tumor therapy. Monotherapy for the treatment of tumors has limited effects due to the limitation of response conditions and inevitable multidrug resistance, which seriously affect the clinical therapeutic effect. In this study, we chose to construct a multiple cascade synergistic tumor drug delivery system MIL-101(Fe)-DOX-TCPP-MnO2@PDA-Ag (MDTM@P-Ag) using MOFs as drug carriers. Under near-infrared (NIR) laser irradiation, 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) and Ag NPs loaded on MDTM@P-Ag can be activated to generate cytotoxic reactive oxygen species (ROS) and achieve photothermal conversion, thus effectively inducing the apoptosis of tumor cells and achieving a combined photodynamic/photothermal therapy. Once released at the tumor site, manganese dioxide (MnO2) can catalyze the decomposition of hydrogen peroxide (H2O2) in the acidic microenvironment of the tumor to generate oxygen (O2) and alleviate the hypoxic environment of the tumor. Fe3+/Mn2+ will mediate a Fenton/Fenton-like reaction to generate cytotoxic hydroxyl radicals (·OH), while depleting the high concentration of glutathione (GSH) in the tumor, thus enhancing the chemodynamic therapeutic effect. The successful preparation of the tumor drug delivery system and its good synergistic chemodynamic/photodynamic/photothermal therapeutic effect in tumor treatment can be demonstrated by the experimental results of material characterization, performance testing and in vitro experiments.

Nanoparticles targeting the adenosine pathway for cancer immunotherapy

Cancer immunotherapy, as an emerging approach to cancer treatment, has tremendous potential for application. Compared to traditional methods such as surgery, chemotherapy, and radiation therapy, it has the ability to restore the patient's immune system, leading to long-term immune memory with less damage to normal tissues. However, immunotherapy has its limitations, including limited therapeutic efficacy, restricted patient populations, and inconsistent treatment responses. Finding effective immunotherapeutic approaches has become a key focus of its clinical application. The adenosine pathway is a recently discovered tumor immune regulatory signaling pathway. It can influence the metabolism and growth of tumor cells by acting through key enzymes in the adenosine pathway, thereby affecting the development of tumors. Therefore, inhibiting the adenosine pathway is an effective cancer immunotherapy. Common adenosine pathway inhibitors include small molecules and antibody proteins, and extensive preclinical trials have demonstrated their effectiveness in inhibiting tumor growth. The short half-life, low bioavailability, and single administration route of adenosine pathway inhibitors limit their clinical application. With the advent of nanotechnology, nano-delivery of adenosine pathway inhibitors has addressed these issues. Compared to traditional drugs, nano-drugs extend the drug's circulation time and improve its distribution within the body. They also offer targeting capabilities and have low toxic side effects, making them very promising for future applications. In this review, we discuss the mechanism of the adenosine pathway in tumor immune suppression, the clinical applications of adenosine pathway inhibitors, and nano-delivery based on adenosine pathway inhibitors. In the final part of this article, we also briefly discuss the technical issues and challenges currently present in nano-delivery of adenosine pathway inhibitors, with the hope of advancing the progress of adenosine inhibitor nano-drugs in clinical treatment.

A copper-loaded self-assembled nanoparticle for disturbing the tumor redox balance and triple anti-tumor therapy

Both chemodynamic therapy and photodynamic therapy, based on the production of reactive oxygen (ROS), have excellent potential in cancer therapy. However, the abnormal redox homeostasis in tumor cells, especially the overexpressed glutathione (GSH) could scavenge ROS and reduce the anti-tumor efficiency. Therefore, it is essential to develop a simple and effective tumor-specific drug delivery system for modulating the tumor microenvironment (TME) and achieving synergistic therapy at the tumor site. In this study, self-assembled nanoparticles (named CDZP NPs) were developed using copper ion (Cu2+), doxorubicin (Dox), zinc phthalocyanine (ZnPc) and a trace amount of poly(2-(di-methylamino)ethylmethacrylate)-poly[(R)-3-hydroxybutyrate]-poly(2-(dimethylamino)ethylmethacrylate) (PDMAEMA-PHB-PDMAEMA) through chelation, π-π stacking and hydrophobic interaction. These triple factor-responsive (pH, laser and GSH) nanoparticles demonstrated unique advantages through the synergistic effect. Highly controllable drug release ensured its effectiveness at the tumor site, Dox-induced chemotherapy and ZnPc-mediated fluorescence (FL) imaging exhibited the distribution of nanoparticles. Meanwhile, Cu2+-mediated GSH-consumption not only reduced the intracellular ROS elimination but also produced Cu+ to catalyze hydrogen peroxide (H2O2) and generated hydroxyl radicals (˙OH), thereby enhancing the chemodynamic and photodynamic therapy. Herein, this study provides a green and relatively simple method for preparing multifunctional nanoparticles that can effectively modulate the TME and improve synergetic cancer therapy.

Immunoantitumor Activity and Oxygenation Effect Based on Iron-Copper-Doped Folic Acid Carbon Dots

Cancer metastasis and recurrence are closely associated with immunosuppression and a hypoxic tumor microenvironment. Chemodynamic therapy (CDT) and photothermodynamic therapy (PTT) have been shown to induce immunogenic cell death (ICD), effectively inhibiting cancer metastasis and recurrence when combined with immune adjuvants. However, the limited efficacy of Fenton's reaction and suboptimal photothermal effect present significant challenges for successfully inducing ICD through CDT and PTT. This paper described the synthesis and immunoantitumor activity of the novel iron-copper-doped folic acid carbon dots (CFCFB). Copper-doped folic acid carbon dots (Cu-FACDs) were initially synthesized via a hydrothermal method, using folic acid and copper gluconate as precursors. Subsequently, the nanoparticles CFCFB were obtained through cross-linking and self-assembly of Cu-FACDs with ferrocene dicarboxylic acid (FeDA) and 3-bromopyruvic acid (3BP). The catalytic effect of carbon dots in CFCFB enhanced the activity of the Fenton reaction, thereby promoting CDT-induced ICD and increasing the intracellular oxygen concentration. Additionally, 3BP inhibited cellular respiration, further amplifying the oxygen concentration. The photothermal conversion efficiency of CFCFB reached 55.8%, which significantly enhanced its antitumor efficacy through photothermal therapy. Immunofluorescence assay revealed that treatment with CFCFB led to an increased expression of ICD markers, including calreticulin (CRT) and ATP, as well as extracellular release of HMGB-1, indicating the induction of ICD by CFCFB. Moreover, the observed downregulation of ARG1 expression indicates a transition in the tumor microenvironment from an immunosuppressive state to an antitumor state following treatment with CFCFB. The upregulation of IL-2 and CD8 expression facilitated the differentiation of effector T cells, resulting in an augmented population of CD8+ T cells, thereby indicating the activation of systemic immune response.

A biomimetic cuproptosis amplifier for targeted NIR-II fluorescence/photoacoustic imaging-guided synergistic NIR-II photothermal immunotherapy

The therapeutic efficacy of cuproptosis combined with phototheranostics is still hindered by easy copper efflux, nonspecific accumulation and limited light penetration depth. Here, a high-performance NIR-II semiconductor polymer was first synthesized through dual-donor engineering. Then a biomimetic cuproptosis amplifier (PCD@CM) was prepared by Cu(II)-mediated coordinative self-assembly of NIR-II ultrasmall polymer dots and the chemotherapeutic drug DOX, followed by camouflaging of tumor cell membranes. After homologous targeting delivery to tumor cells, overexpressed GSH in the tumor microenvironment (TME) triggers the disassembly of the amplifier and the release of therapeutic components through the reduction of Cu(II) to Cu(I), which enable NIR-II fluorescence/photoacoustic imaging-guided NIR-II photothermal therapy (PTT) and chemotherapy. The released Cu(I) induces the aggregation of lipoylated mitochondrial proteins accompanied by the loss of iron-sulfur proteins, leading to severe proteotoxic stress and eventually cuproptosis. NIR-II PTT and GSH depletion render tumor cells more sensitive to cuproptosis. The amplified cuproptosis sensitization provokes significant immune surveillance, triggering the immunogenic cell death (ICD) to promote cytotoxic T lymphocyte infiltration together with aPD-L1-mediated immune checkpoint blockade. This work proposes a new strategy to develop cuproptosis sensitization systems enhanced by NIR-II phototheranostics with homologous targeting and anti-tumor immune response capabilities.

Dual-Programmable Semiconducting Polymer NanoPROTACs for Deep-Tissue Sonodynamic-Ferroptosis Activatable Immunotherapy

Proteolysis-targeting chimeras (PROTACs) can provide promising opportunities for cancer treatment, while precise regulation of their activities remains challenging to achieve effective and safe therapeutic outcomes. A semiconducting polymer nanoPROTAC (SPNFeP ) is reported that can achieve ultrasound (US) and tumor microenvironment dual-programmable PROTAC activity for deep-tissue sonodynamic-ferroptosis activatable immunotherapy. SPNFeP is formed through a nano-precipitation of a sonodynamic semiconducting polymer, a ferroptosis inducer, and a newly synthesized PROTAC molecule. The semiconducting polymers work as sonosensitizers to produce singlet oxygen (1 O2 ) via sonodynamic effect under US irradiation, and ferroptosis inducers react with intratumoral hydrogen peroxide (H2 O2 ) to generate hydroxyl radical (·OH). Such a dual-programmable reactive oxygen species (ROS) generation not only triggers ferroptosis and immunogenic cell death (ICD), but also induces on-demand activatable delivery of PROTAC molecules into tumor sites. The effectively activated nanoPROTACs degrade nicotinamide phosphoribosyl transferase (NAMPT) to suppress tumor infiltration of myeloid-derived suppressive cells (MDSCs), thus promoting antitumor immunity. In such a way, SPNFeP mediates sonodynamic-ferroptosis activatable immunotherapy for entirely inhibiting tumor growths in both subcutaneous and 2-cm tissue-covered deep tumor mouse models. This study presents a dual-programmable activatable strategy based on PROTACs for effective and precise cancer combinational therapy.

Nanomaterials augmented bioeffects of ultrasound in cancer immunotherapy

Immunotherapy as a milestone in cancer treatment has made great strides in the past decade, but it is still limited by low immune response rates and immune-related adverse events. Utilizing bioeffects of ultrasound to enhance tumor immunotherapy has attracted more and more attention, including sonothermal, sonomechanical, sonodynamic and sonopiezoelectric immunotherapy. Moreover, the emergence of nanomaterials has further improved the efficacy of ultrasound mediated immunotherapy. However, most of the summaries in this field are about a single aspect of the biological effects of ultrasound, which is not comprehensive and complete currently. This review proposes the recent progress of nanomaterials augmented bioeffects of ultrasound in cancer immunotherapy. The concept of immunotherapy and the application of bioeffects of ultrasound in cancer immunotherapy are initially introduced. Then, according to different bioeffects of ultrasound, the representative paradigms of nanomaterial augmented sono-immunotherapy are described, and their mechanisms are discussed. Finally, the challenges and application prospects of nanomaterial augmented ultrasound mediated cancer immunotherapy are discussed in depth, hoping to pave the way for cancer immunotherapy and promote the clinical translation of ultrasound mediated cancer immunotherapy through the reasonable combination of nanomaterials augmented ultrasonic bioeffects.

Sono-Activatable Semiconducting Polymer Nanoreshapers Multiply Remodel Tumor Microenvironment for Potent Immunotherapy of Orthotopic Pancreatic Cancer

Due to the complicated tumor microenvironment that compromises the efficacies of various therapies, the effective treatment of pancreatic cancer remains a big challenge. Sono-activatable semiconducting polymer nanoreshapers (SPNDN H) are constructed to multiply remodel tumor microenvironment of orthotopic pancreatic cancer for potent immunotherapy. SPNDN H contain a semiconducting polymer, hydrogen sulfide (H2 S) donor, and indoleamine 2,3-dioxygenase (IDO) inhibitor (NLG919), which are encapsulated by singlet oxygen (1 O2 )-responsive shells with modification of hyaluronidase (HAase). After accumulation in orthotopic pancreatic tumor sites, SPNDN H degrade the major content of tumor microenvironment hyaluronic acid to promote nanoparticle enrichment and immune cell infiltration, and also release H2 S to relieve tumor hypoxia via inhibiting mitochondrion functions. Moreover, the relieved hypoxia enables amplified sonodynamic therapy (SDT) under ultrasound (US) irradiation with generation of 1 O2 , which leads to immunogenic cell death (ICD) and destruction of 1 O2 -responsive components to realize sono-activatable NLG919 release for reversing IDO-based immunosuppression. Through such a multiple remodeling mechanism, a potent antitumor immunological effect is triggered after SPNDN H-based treatment. Therefore, the growths of orthotopic pancreatic tumors in mouse models are almost inhibited and tumor metastases are effectively restricted. This study offers a sono-activatable nanoplatform to multiply remodel tumor microenvironment for effective and precise immunotherapy of deep-tissue orthotopic tumors.

Improvement of the effectiveness of sonodynamic therapy: by optimizing components and combination with other treatments

Sonodynamic therapy (SDT) is an emerging treatment method. In comparison with photodynamic therapy (PDT), SDT exhibits deep penetration, high cell membrane permeability, and free exposure to light capacity. Unfortunately, owing to inappropriate ultrasound parameter selection, poor targeting of sonosensitizers, and the complex tumor environment, SDT is frequently ineffective. In this review, we describe the approaches for selecting ultrasound parameters and how to develop sonosensitizers to increase targeting and improve adverse tumor microenvironments. Furthermore, the potential of combining SDT with other treatment methods, such as chemotherapy, chemodynamic therapy, photodynamic therapy, photothermal therapy, and immunotherapy, is discussed to further increase the treatment efficiency of SDT.

Prodrug-loaded semiconducting polymer hydrogels for deep-tissue sono-immunotherapy of orthotopic glioblastoma

Although immunotherapy has achieved great success in the treatment of a variety of tumors, its efficacy for glioblastoma (GBM) is still limited. Both the immunosuppressive tumor microenvironment (TME) and poor penetration of immunotherapeutic agents into tumors contributed to the poor anti-glioma immunity. Herein, we develop an injectable prodrug-loaded hydrogel delivery system with sono-activatable properties for sonodynamic therapy (SDT)-triggered immunomodulation for GBM treatment. The prodrug alginate hydrogels (APN), which contain semiconducting polymer nanoparticles (SPNs) and the NLG919 prodrug linked by singlet oxygen (1O2)-cleavable linkers, are in situ formed via coordination of alginate solution with Ca2+ in the TME. SPNs serve as sonosensitizers to produce 1O2 upon ultrasound (US) irradiation for SDT. The generated 1O2 not only induce immunogenic cell death, but also break 1O2-cleavable linkers to precisely activate the NLG919 prodrug. Antitumor immunity is significantly amplified due to the reversal of immunosuppression mediated by indolamine 2,3-dioxygenase-dependent tryptophan metabolism. This smart prodrug hydrogel platform potently inhibits tumor growth in orthotopic glioma-bearing mice. Collectively, this work provides a sono-activatable hydrogel platform for precise sono-immunotherapy against GBM.

Stimuli responsive nanosonosensitizers for sonodynamic therapy

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

Activatable Semiconducting Polymer Nanoinducers Amplify Oxidative Damage via Sono-Ferroptosis for Synergistic Therapy of Bone Metastasis

Bone metastases are secondary malignant tumors that commonly occur after the spread of advanced cancer cells. We herein report the activatable semiconducting polymer nanoinducers (ASPNFP) that can amplify oxidative damage via sono-ferroptosis for bone metastasis treatment. ASPNFP are constructed by encapsulating plasma amine oxidase-based semiconducting polymer nanoparticles (SPNP) and Fe3O4 nanoparticles into singlet oxygen (1O2)-responsive nanocarriers. ASPNFP generate 1O2 under ultrasound (US) irradiation via a sonodynamic effect to destroy the stability of 1O2-responsive nanocarriers, allowing US-triggered releases of SPNP and Fe3O4 nanoparticles. SPNP decompose polyamines in tumor cells to produce acrolein and hydrogen peroxide (H2O2), in which H2O2 promotes Fenton reaction mediated by Fe3O4 nanoparticles for inducing enhanced ferroptosis and generation of hydroxyl radicals (•OH). The generated acrolein, 1O2, and •OH can simultaneously amplify the oxidative damage. ASPNFP thus mediate an amplified sono-ferroptosis effect to inhibit the growth of bone metastasis and restrict tumor metastasis.

Cancer Metabolism: The Role of ROS in DNA Damage and Induction of Apoptosis in Cancer Cells

Cancer is a huge challenge for people worldwide. High reactive oxygen species (ROS) levels are a recognized hallmark of cancer and an important aspect of cancer treatment research. Abnormally elevated ROS levels are often attributable to alterations in cellular metabolic activities and increased oxidative stress, which affects both the development and maintenance of cancer. Moderately high levels of ROS are beneficial to maintain tumor cell genesis and development, while toxic levels of ROS have been shown to be an important force in destroying cancer cells. ROS has become an important anticancer target based on the proapoptotic effect of toxic levels of ROS. Therefore, this review summarizes the role of increased ROS in DNA damage and the apoptosis of cancer cells caused by changes in cancer cell metabolism, as well as various anticancer therapies targeting ROS generation, in order to provide references for cancer therapies based on ROS generation.