Bioactive Iridium Nanoclusters with Glutathione Depletion Ability for Enhanced Sonodynamic-Triggered Ferroptosis-Like Cancer Cell Death

High resolution two photon fluorescence probe monitoring ClO- based on anion exchange for the synergistic ROS and ferroptosis activated by thermal energy

Ferroptosis, closely correlated with hypochlorite (ClO-), is an emerging form of iron-dependent cell death. Exploring the ClO- content in living cells will help to further reveal the biological function of ferroptosis. In this work, we have developed a two-photon excited fluorescent probe (CMI-ClO) which can detect the ClO- changes during ferroptosis. CMI-ClO can specifically response to ClO- by exchanging with I-. The multiple reactive oxygen species (ROS) are produced simultaneously in the ClO- identification process. More significantly, CMI-ClO produces ROS through thermal energy, breaking the limitation of light trigged conventional photosensitizers. CMI-ClO can achieve high resolution tracking of ferroptosis under NIR II excitation, where ROS and ferroptosis combine to cause mitochondrial damage and cell death. This work provides a synergistic strategy for enhancing ROS and ferroptosis therapy.

Nanozyme as tumor energy homeostasis disruptor mediated ferroptosis for high-efficiency radiotherapy

Radioresistance in tumors, driven by the insufficiency and rapid depletion of reactive oxygen species (ROS), limits the efficacy of radiotherapy (RT). This study introduces an Ir@Au nanozyme that enhances tumor radiosensitivity by disrupting energy homeostasis and inducing ferroptosis in tumor cells. The Ir@Au nanozyme mimics glucose oxidase to block the tumor's energy supply, continuously produces hydrogen peroxide (H2O2), and lowers the pH to optimize Fenton reactions. Acting as a peroxidase (POD), it generates additional ROS for chemodynamic therapy (CDT), depletes glutathione (GSH), and perturbs the tumor's antioxidant defenses. Upon exposure to ionizing radiation, the nanozyme absorbs photons and emits electrons, interacting with water to amplify ROS production. This ROS accumulation, combined with radiation, enhances DNA damage and lipid peroxidation, reversing radioresistance and promoting ferroptosis. Additionally, Ir@Au serves as a contrast agent for computed tomography, enabling precise RT through the delineation of tumor boundaries. In summary, the Ir@Au nanozyme effectively disrupts tumor energy homeostasis, initiating ROS-based cascades that inhibit tumor growth. It thus offers a promising strategy for overcoming radioresistance during cancer therapy.

Biodegradable copper-doped calcium phosphate nanoplatform enables tumor microenvironment modulations for amplified ferroptosis in cervical carcinoma treatment

As a recently discovered form of regulated cell death, ferroptosis has attracted much attention in the field cancer therapy. However, achieving considerably enhanced efficacy is often restricted by the overexpression of endogenous glutathione (GSH) in tumor microenvironment (TME). In this work, we report a ferroptosis-inducing strategy of GSH depletion and reactive oxygen species (ROS) generation based on a biodegradable copper-doped calcium phosphate (CaP) with L-buthionine sulfoximine (BSO) loading (denoted as BSO@CuCaP-LOD, BCCL). BCCL was conducted by a biomineralization approach using lactate oxidases (LOD) as a bio-template to obtain Cu-doped CaP nanoparticles. Then, BSO was loaded to form BCCL nanoparticles with pH-responsive biodegradability to endow controlled release of Cu2+ and BSO in response to acidic TME. Benefiting from the catalytic performance of LOD, BCCL efficiently depletes the level of lactate in tumor, which can generate endogenous H2O2 for subsequent Fenton-like reaction. The Cu2+ and BSO intracellular GSH depletion followed by GSH-mediated Cu2+/Cu+ conversion, leading to the inhibition of glutathione peroxidase 4 (GPX4) and generation of •OH radicals via Cu+-mediated Fenton-like reaction. BCCL confers enhanced ferroptosis induction via intracellular LOD-induced H2O2 production, BSO-mediated GSH depletion, and Cu+-mediated ROS generation, leading to cause effective ferroptotic cell damage. As verified by in vitro and in vivo assays, the designed BCCL nanoplatform is highly biocompatible and exhibits superior anticancer therapy on uterine cervical carcinoma U14 tumor xenografts. This study, therefore, provides a biocompatible therapeutic platform that modulating the TME to enable intensive ROS generating efficacy and GSH depleting performance, as well as provides an innovative paradigm for achieving effective ferroptosis-based cancer therapy.

Smart Type I Squaraine Nano-Photosensitizer Combined with MnO2 for Tumor-Targeted and Ferroptosis-Induced Immunogenic Photodynamic Therapy

Most photosensitizers face enormous challenges in tumor hypoxia, the redox microenvironment, and low immune efficacies for reactive oxygen species (ROS). Herein, dye SQ-580 was constructed by coupling the electron-donating indole and thiophenazine-thiophene with the electron-withdrawing dicyanovinyl squaraine. It exhibited a high generation of •OH and O2•- by decreasing ΔES1T2 and acted as an excellent type I photosensitizer for conquering tumor hypoxia. The nanoplatform involving SQ-580, MnO2, and a targeting peptide CREKA was constructed and targeted breast tumor. In the tumor microenvironment, MnO2 reacted with high-expressed GSH and produced Mn2+, which catalyzed H2O2 to decompose into •OH and induced chemodynamic therapy (CDT). The reduction of GSH inhibited the consumption of SQ-580 and maintained its high photodynamic therapy (PDT) efficacy. GSH depletion and ROS resulted in cell ferroptosis. Under the synergy of ferroptosis and ROS, Mn2+ amplified immunogenic cell death (ICD). In the mouse models, SQ-580@MnO2 NPs showed NIRF/MR imaging-guided tumor targeting, effectively inhibited the growth of the primary and distant tumors, and amplified PDT and immune efficacies in the synergy of PDT, CDT, ferroptosis, and ICD. This study provides an effective strategy to design excellent type I photosensitizers and amplify the PDT and ICD efficacies utilizing valence metals and the tumor microenvironment.

OTUD4 inhibits ferroptosis by stabilizing GPX4 and suppressing autophagic degradation to promote tumor progression

Ferroptosis, a regulated cell demise predicated on iron metabolism and lipid peroxidation, has increasingly become a focal point in oncological therapies. Nonetheless, its governance, particularly the role of deubiquitination, is not fully delineated. This investigation concentrates on the deubiquitinase OTUD4, scrutinizing its functional and molecular implications in ferroptosis within tumor cells. By engineering OTUD4 knockout cell lines via CRISPR-Cas9, we observed that these cells exhibit heightened sensitivity to ferroptosis inducers, augmenting ferroptotic cell death and robustly diminishing tumor growth both in vitro and in vivo. Mechanistically, OTUD4 not only sustains protein stability by directly deubiquitinating GPX4 but also impedes its degradation via RHEB-mediated autophagy, collectively stalling the ferroptosis pathway. In vivo assays substantiate that OTUD4 deletion, when combined with regorafenib, drastically reduces tumor proliferation, showcasing potent synergistic antitumor activity. This study pioneers the revelation of OTUD4's bifunctional role in modulating ferroptosis through deubiquitination and autophagy, underscoring its potential as a therapeutic target in oncology.

Breaking Barriers in Oncology: Harnessing Sonodynamic Therapy for Enhanced Tumor Metabolism Regulation

The recent booming development of sonometabolism regulation in controlling the tumor microenvironment (TME) has opened a new research area to identify innovative approaches against cancer. The aim of this review is to highlight the potentials and advantages of sonodynamic therapy (SDT) in antitumor nanotherapies, specifically, delineating the progress made in SDT concerning the regulation of TME metabolism which encompasses factors such as hypoxia, redox balance, autophagy, immunosuppression, ion homeostasis, and other metabolic processes. By focusing on both tumor cell metabolism and TME dynamics, a wide range of SDT strategies that have demonstrated great therapeutic effectiveness by targeting the metabolic functions inherent to TME are summarized. In conclusion, this review offers valuable insights for researchers involved in SDT-based antitumor therapeutic strategies, with the aim of advancing the development of antitumor SDT methodologies in future research.

High Photocytotoxicity Iridium(III) Complex Photosensitizer for Photodynamic Therapy Induces Antitumor Effect Through GPX4-Dependent Ferroptosis

The development of small molecule photosensitizers based on iridium complex is limited by the mismatch between therapeutic effect and systemic toxicity, as well as the incomplete understanding of the molecular mechanism underlying cell death induction. Herein, a small molecule iridium complex IrC with high photocytotoxicity is synthesized, with half maximal inhibitory concentration as low as 91 nm, demonstrating excellent anti-tumor, relief of splenomegaly, and negligible side effects. Starting from the factors of effective photosensitizers, the in-depth theoretical analysis on photon absorption efficiency, energy transfer level matching, and properties of the triplet excited state of IrC is conducted. This also elucidates the feasibility of generating the high singlet oxygen quantum yield. In addition, the death mechanism induced by IrC is focused, innovatively utilizing GPX4-overexpression and GPX4-knockout cells via CRISPR/Cas9 technique to comprehensively verify ferroptosis and its further molecular mechanism. The generation of ROS mediated by IrC, along with the direct inhibition of GPX4 and glutathione, synergistically increased cellular oxidative stress and the level of lipid peroxidation. This study provides an effective approach for small molecule complexes to induce GPX4-dependent ferroptosis at low-dose photodynamic therapy.

Engineering Iridium Nanoclusters for Boosting Ferroptotic Cell Death by Regulating GPX4 and p53 Functions

Emerging evidence indicates that modulating glutathione peroxidase 4 (GPX4) to induce ferroptosis is a promising strategy for tumor treatment. However, most of the GPX4 small molecule inhibitors face limitations due to their poor delivery efficacy and low specificity of ferroptosis activation. Herein, a ferroptosis-inducing nanomedicine is developed that integrates nutlin-3 with iridium oxide nanoclusters (NUT-IrOx NCs) for enhanced ferroptosis-driven multimodal therapeutic efficacy in colorectal cancer (CRC). This NUT-IrOx NCs can induce glutathione (GSH) depletion via enhanced Ir (VI)-Ir (III) transition, while nutlin-3, a well-established inhibitor of the p53-MDM2 interaction, suppresses GSH production by modulation of the p53/SLC7A11/xCT signaling pathway. The reduction of intracellular GSH results in pronounced reductions of GPX4 enzymatic activity, consequently leading to lipid peroxidation accumulation and further enhancing ferroptosis-induced CRC therapy. This dual-pronged approach demonstrates robust anticancer therapeutic effects with favorable biocompatibility in both in vitro and in vivo CRC models. This study provides an effective strategy that highlights the benefits of inhibiting of GSH/GPX4 by activating multiple ferroptosis regulatory pathways, providing an alternative therapeutic avenue for CRC treatment.

ROS Regulate Rotenone-induced SH-SY5Y Dopamine Neuron Death Through Ferroptosis-mediated Autophagy and Apoptosis

Rotenone, a plant-derived natural insecticide, is widely used to induce Parkinson's disease (PD) models. However, the mechanisms of rotenone-induced cell death remain unclear. Here, we found that rotenone (0.01, 0.1, or 1 μmol/L) suppressed SH-SY5Y dopamine neuron viability and led to PD-like pathological changes, such as reduced tyrosine hydroxylase (TH) but increased α-synuclein. Rotenone increased the levels of intracellular reactive oxygen species (ROS) and mitochondrial ROS, as well as the levels of the antioxidants nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1), ultimately resulting in oxidative stress. Moreover, rotenone significantly downregulated the expression of GPX4 and xCT but upregulated the expression of COX2 and NCOA4, which are markers of ferroptosis. Furthermore, rotenone decreased phosphorylated mTOR level but increased Beclin-1, ATG5, LC3 and p62 expression, suggesting that rotenone enhances autophagy and reduces autophagy flux. Additionally, rotenone reduced Bcl-2 levels and the mitochondrial membrane potential (MMP) while promoting BAX and Caspase-3 expression, thus initiating cell apoptosis. N-acetylcysteine (NAC), a ROS scavenger, and ferrostatin-1 (Fer-1) and deferoxamine (DFO), two ferroptosis inhibitors, significantly eliminated rotenone-induced autophagy and apoptosis. Moreover, ML385, a specific inhibitor of Nrf2, suppressed rotenone-induced ferroptosis. Our results demonstrated that ROS might mediate rotenone-induced PD-like pathological changes by regulating iron death, autophagy, and apoptosis. Inhibiting ferroptosis blocked the rotenone-induced increase in autophagy and apoptosis. Thus, the ability of ROS to regulate rotenone-induced death through autophagy and apoptosis is dependent on ferroptosis. The findings require validation in multiple neuronal cell lines and in vivo.

Applications and enhancement strategies of ROS-based non-invasive therapies in cancer treatment

Reactive oxygen species (ROS) play a crucial role in the pathogenesis of cancer. Non-invasive therapies that promote intracellular ROS generation, including photodynamic therapy (PDT), sonodynamic therapy (SDT), and chemodynamic therapy (CDT), have emerged as novel approaches for cancer treatment. These therapies directly kill tumor cells by generating ROS, and although they show great promise in tumor treatment, many challenges remain to be addressed in practical applications. Firstly, the inherent complexity of the tumor microenvironment (TME), such as hypoxia and elevated glutathione (GSH) levels, hinders ROS generation, thereby significantly diminishing the efficacy of ROS-based therapies. In addition, these therapies are influenced by their intrinsic mechanisms. To overcome these limitations, various nanoparticle (NP) systems have been developed to improve the therapeutic efficacy of non-invasive therapies against tumors. This review first summarizes the mechanisms of ROS generation for each non-invasive therapy and their current limitations, with a particular focus on the enhancement strategies for each therapy based on NP systems. Additionally, various strategies to modulate the TME are highlighted. These strategies aim to amplify ROS generation in non-invasive therapies and enhance their anti-tumor efficiency. Finally, the current challenges and possible solutions for the clinical translation of ROS-based non-invasive therapies are also discussed.

Chemical Design of Magnetic Nanomaterials for Imaging and Ferroptosis-Based Cancer Therapy

Ferroptosis, an iron-dependent form of regulatory cell death, has garnered significant interest as a therapeutic target in cancer treatment due to its distinct characteristics, including lipid peroxide generation and redox imbalance. However, its clinical application in oncology is currently limited by issues such as suboptimal efficacy and potential off-target effects. The advent of nanotechnology has provided a new way for overcoming these challenges through the development of activatable magnetic nanoparticles (MNPs). These innovative MNPs are designed to improve the specificity and efficacy of ferroptosis induction. This Review delves into the chemical and biological principles guiding the design of MNPs for ferroptosis-based cancer therapies and imaging-guided therapies. It discusses the regulatory mechanisms and biological attributes of ferroptosis, the chemical composition of MNPs, their mechanism of action as ferroptosis inducers, and their integration with advanced imaging techniques for therapeutic monitoring. Additionally, we examine the convergence of ferroptosis with other therapeutic strategies, including chemodynamic therapy, photothermal therapy, photodynamic therapy, sonodynamic therapy, and immunotherapy, within the context of nanomedicine strategies utilizing MNPs. This Review highlights the potential of these multifunctional MNPs to surpass the limitations of conventional treatments, envisioning a future of drug-resistance-free, precision diagnostics and ferroptosis-based therapies for treating recalcitrant cancers.

Nanomaterials Enhanced Sonodynamic Therapy for Multiple Tumor Treatment

Sonodynamic therapy (SDT) as an emerging modality for malignant tumors mainly involves in sonosensitizers and low-intensity ultrasound (US), which can safely penetrate the tissue without significant attenuation. SDT not only has the advantages including high precision, non-invasiveness, and minimal side effects, but also overcomes the limitation of low penetration of light to deep tumors. The cytotoxic reactive oxygen species can be produced by the utilization of sonosensitizers combined with US and kill tumor cells. However, the underlying mechanism of SDT has not been elucidated, and its unsatisfactory efficiency retards its further clinical application. Herein, we shed light on the main mechanisms of SDT and the types of sonosensitizers, including organic sonosensitizers and inorganic sonosensitizers. Due to the development of nanotechnology, many novel nanoplatforms are utilized in this arisen field to solve the barriers of sonosensitizers and enable continuous innovation. This review also highlights the potential advantages of nanosonosensitizers and focus on the enhanced efficiency of SDT based on nanosonosensitizers with monotherapy or synergistic therapy for deep tumors that are difficult to reach by traditional treatment, especially orthotopic cancers.

Ultrasound-Activated Copper Matrix Nanosonosensitizer for Cuproptosis-Based Synergy Therapy

Cuproptosis exhibits enormous application prospects in treatment. However, cuproptosis-based therapy is impeded by the limited intracellular copper ions, the nonspecific delivery, uncontrollable release, and chelation of endogenous overproduced glutathione (GSH). In this work, an ultrasound-triggered nanosonosensitizer (p-TiO2-Cu(I)) was constructed for Cu(I) delivery, on-demand release, GSH consumption, and deeper tissue response. When the nanomedicine was internalized into the tumor cells, ultrasound (US) induced the nanosonosensitizer to produce reactive oxygen species (ROS) to achieve sonodynamic therapy (SDT). GSH, acting as a hole trapping agent, improved the efficiency of SDT. Meanwhile, the downgrade of GSH was beneficial to cuproptosis and oxidative damage-based SDT in return. What is more, the US could regulate the release behavior of Cu(I). Cu(I) bonded to mitochondrial proteins and then aggregated the lipoylated protein, bringing about the turbulence of the tricarboxylic acid cycle. The combination of SDT and cuproptosis showed high matching to induce efficient cuproptosis and may inspire other cuproptosis-based nanosonosensitizer designs.

Glutathione-Depleted Photodynamic Nanoadjuvant for Triggering Nonferrous Ferroptosis to Amplify Radiotherapy of Breast Cancer

Radiotherapy plays a crucial role in the treatment of advanced breast cancer, but the increased antioxidant system, especially the rise in glutathione (GSH), presents a significant obstacle to its effectiveness. To address this challenge, a versatile GSH-depleted photodynamic nanoadjuvant is developed to augment the efficacy of radiotherapy for breast cancer treatment. This nanoadjuvant operates within the tumor microenvironment to effectively deplete intracellular GSH through a sequence of cascaded processes, including GSH exhaustion, biosynthetic inhibition, and photodynamic oxidation. This leads to a notable accumulation of lipid peroxides (LPO) and subsequent suppression of glutathione peroxidase 4 (GPX4) activity. Consequently, the combined GSH depletion induced by the nanoadjuvant markedly promotes nonferrous ferroptosis, thereby contributing to the augmentation of antitumor efficiency during radiotherapy in breast cancer. This work presents an innovative approach to designing and synthesizing biocompatible nanoadjuvants with the goal of improving the efficacy of radiotherapy for breast cancer in prospective clinical scenarios.

Therapeutic types and advantages of functionalized nanoparticles in inducing ferroptosis in cancer therapy

BACKGROUND

The clinical efficacy of cancer treatment protocols remains unsatisfactory; however, the emergence of ferroptosis-driven therapy strategies has renewed hope for tumor treatment, owing to their remarkable tumor suppression effects. Biologically based small-molecule inducers are used in conventional method to induce ferroptosis. Nevertheless, some molecular drugs have limited solubility, poor ability to target cells, and fast metabolism, which hinder their ability to induce ferroptosis over a prolonged period. Fortunately, further investigations of ferroptosis and the development of nanotechnology have demonstrated that nanoparticles (NPs) are more efficient in inducing ferroptosis than drugs alone, which opens up new perspectives for cancer therapy.

OBJECTIVE

In order to organize a profile of recent advance in NPs for inducing ferroptosis in cancer therapy, and NPs were comprehensively classified in a new light.Materials and methods: We comprehensively searched the databases such as PubMed and Embase. The time limit for searching was from the establishment of the database to 2023.11. All literatures were related to "ferroptosis", "nanoparticles", "nanodelivery systems", "tumors", "cancer".

RESULTS

We summarized and classified the available NPs from a new perspective. The NPs were classified into six categories based on their properties: (1) iron oxide NPs (2) iron - based conversion NPs (3) core-shell structure (4) organic framework (5) silica NPs (6) lipoprotein NPs. According to the therapeutic types of NPs, they can be divided into categories: (1) NPs induced ferroptosis-related immunotherapy (2) NPs loaded with drugs (3) targeted therapy of NPs (4) multidrug resistance therapy (5) gene therapy with NPs (6) energy conversion therapy.

CONCLUSIONS

The insights gained from this review can provide ideas for the development of original NPs and nanodelivery systems, pave the way for related nanomaterials application in clinical cancer therapy, and advance the application and development of nanotechnology in the medical field.

A Robust ROS Generation and Ferroptotic Lipid Modulation Nanosystem for Mutual Reinforcement of Ferroptosis and Cancer Immunotherapy

Ferroptosis initiation is often utilized for synergistic immunotherapy. While, current immunotherapy is limited by an immunosuppressive tumor microenvironment (TME), and ferroptosis is limited by insufficient reactive oxygen species (ROS) and ferroptotic lipids in tumor cells. Here, an arachidonic acid (AA) loaded nanosystem (CTFAP) is developed to mutually reinforce ferroptosis and cancer immunotherapy by augmenting ROS generation and modulating ferroptotic lipids. CTFAP is composed of acid-responsive core calcium peroxide (CaO2) nanoparticles, ferroptotic lipids sponsor AA, tetracarboxylic porphyrin (TCPP) and Fe3+ based metal-organic framework structure, and biocompatible mPEG-DSPE for improved stability. Once endocytosed by tumor cells, CTFAP can release oxygen (O2) and hydrogen peroxide (H2O2) in the acidic TME, facilitating TCPP-based sonodynamic therapy and Fe3+-mediated Fenton-like reactions to generate substantial ROS for cell ferroptosis initiation. The immunogenic cell death (ICD) after ferroptosis promotes interferon γ (IFN-γ) secretion to up-regulate the expression of long-chain family member 4 (ACSL4), cooperating with the released AA from CTFAP to accelerate the accumulation of lipid peroxidation (LPO) and thereby promoting ferroptosis in cancer cells.CTFAP with ultrasound treatment efficiently suppresses tumor growth, has great potential to challenges in cancer immunotherapy.

Light-activated nanoclusters with tunable ROS for wound infection treatment

Infected wounds pose a significant clinical challenge due to bacterial resistance, recurrent infections, and impaired healing. Reactive oxygen species (ROS)-based strategies have shown promise in eradicating bacterial infections. However, the excess ROS in the infection site after treatments may cause irreversible damage to healthy tissues. To address this issue, we developed bovine serum albumin-iridium oxide nanoclusters (BSA-IrOx NCs) which enable photo-regulated ROS generation and scavenging using near infrared (NIR) laser. Upon NIR laser irradiation, BSA-IrOx NCs exhibit enhanced photodynamic therapy, destroying biofilms and killing bacteria. When the NIR laser is off, the nanoclusters' antioxidant enzyme-like activities prevent inflammation and repair damaged tissue through ROS clearance. Transcriptomic and metabolomic analyses revealed that BSA-IrOx NCs inhibit bacterial nitric oxide synthase, blocking bacterial growth and biofilm formation. Furthermore, the nanoclusters repair impaired skin by strengthening cell junctions and reducing mitochondrial damage in a fibroblast model. In vivo studies using rat infected wound models confirmed the efficacy of BSA-IrOx NCs. This study presents a promising strategy for treating biofilm-induced infected wounds by regulating the ROS microenvironment, addressing the challenges associated with current ROS-based antibacterial approaches.

Engineering a porphyrin COFs encapsulated by hyaluronic acid tumor-targeted nanoplatform for sequential chemo-photodynamic multimodal tumor therapy

Numerous barriers hinder the entry of drugs into cells, limiting the effectiveness of tumor pharmacotherapy. Effective penetration into tumor tissue and facilitated cellular uptake are crucial for the efficacy of nanotherapeutics. Photodynamic therapy (PDT) is a promising approach for tumor suppression. In this study, we developed a size-adjustable porphyrin-based covalent organic framework (COF), further modified with hyaluronic acid (HA), to sequentially deliver drugs for combined chemo-photodynamic tumor therapy. A larger COF (P-COF, approximately 500 nm) was loaded with the antifibrotic drug losartan (LST) to create LST/P-COF@HA (LCH), which accumulates at tumor sites. After injection, LCH releases LST, downregulating tumor extracellular matrix (ECM) component levels and decreasing collagen density, thus reducing tumor solid stress. Additionally, the reactive oxygen species (ROS) generated from LCH under 660 nm laser irradiation induce lipid peroxidation of cell membranes. Owing to its larger particle size, LCH primarily functions extracellularly, paving the way for subsequent treatments. Following intravenous administration, the smaller COF (p-COF, approximately 200 nm) loaded with doxorubicin (DOX) and modified with HA (DOX/p-COF@HA, DCH) readily enters cells in the altered microenvironment. Within tumor cells, ROS generated from DCH facilitates PDT, while the released DOX targets cancer cells via chemotherapy, triggered by disulfide bond cleavage in the presence of elevated glutathione (GSH) levels. This depletion of GSH further enhances the PDT effect. Leveraging the size-tunable properties of the porphyrin COF, this platform achieves a multifunctional delivery system that overcomes specific barriers at optimal times, leading to improved outcomes in chemo-photodynamic multimodal tumor therapy in vivo.

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.

A Bimetallic Nanomodulator to Reverse Immunosuppression via Sonodynamic-Ferroptosis and Lactate Metabolism Modulation

Triple-negative breast cancer (TNBC) responds poorly to immunotherapy due to insufficient immunogenicity and highly immunosuppressive tumor microenvironment (TME). Herein, an intelligent calcium/cobalt-based nanomodulator (Ca,Co)CO3-LND-TCPP@F127-TA (abbreviated as CCLT@FT) is developed to act as a sonodynamic-ferroptosis inducer and metabolic immunoadjuvant to enhance anti-tumor immunotherapy. More details, simultaneous reactive oxygen species (ROS) generation and glutathione (GSH) depletion can be achieved due to the existence of Co2+/Co3+ redox couple in CCLT@FT. Meanwhile, mitochondrial Ca2+ overload and tetrakis(4-carboxyphenyl) porphyrin (TCPP)-mediated sonodynamic therapy (SDT) further amplify the oxidative stress and promote ferroptosis in tumor cells. More impressively, CCLT@FT can modulate lactate metabolism by doping with cobalt and loading with lonidamine (LND, an inhibitor of MCT4), thereby reversing the high-lactate immunosuppressive TME. Furthermore, the combination with immune checkpoint blockade (ICB) therapy is found to achieve superior anti-tumor immunity, which in turn promotes ferroptosis of tumor cells by downregulating SLC7A11 protein, ultimately creating a "cycle" therapy. Overall, this work demonstrates a novel strategy for enhancing anti-tumor immunotherapy based on a closed-loop enhancement therapeutic route between CCLT@FT inducing ferroptosis/lactate metabolism modulation and ICB therapy, providing an alternative and important reference for effective immunotherapy of TNBC.

Nanosonosensitizer Optimization for Enhanced Sonodynamic Disease Treatment

Low-intensity ultrasound-mediated sonodynamic therapy (SDT), which, by design, integrates sonosensitizers and molecular oxygen to generate therapeutic substances (e.g., toxic hydroxyl radicals, superoxide anions, or singlet oxygen) at disease sites, has shown enormous potential for the effective treatment of a variety of diseases. Nanoscale sonosensitizers play a crucial role in the SDT process because their structural, compositional, physicochemical, and biological characteristics are key determinants of therapeutic efficacy. In particular, advances in materials science and nanotechnology have invigorated a series of optimization strategies for augmenting the therapeutic efficacy of nanosonosensitizers. This comprehensive review systematically summarizes, discusses, and highlights state-of-the-art studies on the current achievements of nanosonosensitizer optimization in enhanced sonodynamic disease treatment, with an emphasis on the general design principles of nanosonosensitizers and their optimization strategies, mainly including organic and inorganic nanosonosensitizers. Additionally, recent advancements in optimized nanosonosensitizers for therapeutic applications aimed at treating various diseases, such as cancer, bacterial infections, atherosclerosis, and autoimmune diseases, are clarified in detail. Furthermore, the biological effects of the improved nanosonosensitizers for versatile SDT applications are thoroughly discussed. The review concludes by highlighting the current challenges and future opportunities in this rapidly evolving research field to expedite its practical clinical translation and application.

TiO2-Nanoparticle-Enhanced Sonodynamic Therapy for Prevention of Posterior Capsular Opacification and Ferroptosis Exploration of Its Mechanism

Purpose

To explore the application and potential ferroptosis mechanisms of sonodynamic therapy (SDT) using titanium dioxide nanoparticles (TiO2-NPs) as sonosensitizers for the prevention of posterior capsule opacification (PCO).

Methods

We fabricated TiO2-NP-coated intraocular lenses (TiO2-IOLs) using the spin-coating method, followed by ultrasound activation of the photosensitizer TiO2. In vitro experiments were performed with human lens epithelial cells (HLECs) to explore the appropriate concentration of TiO2 and ultrasonic parameters. Investigations included reactive oxygen species (ROS) generation, glutathione (GSH) depletion, glutathione peroxidase 4 (GPX4) western blot analysis, lipid peroxidation assays, and transcriptomics analysis. Finally, TiO2-IOLs were implanted in rabbit eyes to explore the in vivo performance of SDT.

Results

Through both in vitro and in vivo experiments, the study determined that the ultrasound parameters of 5-minute duration, 1-MHz frequency, 50% duty cycle, and 1.2-W/cm2 intensity were reliable and valid for killing HLECs without damaging other ocular structures. In vitro experiments demonstrated that SDT generated excess ROS, which disrupted the mitochondrial membrane potential and significantly reduced the GSH content. Additionally, the downregulation of GPX4, accumulation of lipid peroxides, and alteration of mitochondrial morphology were observed, suggesting that ferroptosis may be the underlying mechanism. The RNA-sequencing analysis results also showed an increase in the expression of multiple pro-ferroptosis genes and the ferroptosis marker gene PTGS2. Animal experiments preliminarily demonstrated the safety and effectiveness of SDT in treating PCO in vivo.

Conclusions

TiO2-IOLs combined with SDT effectively prevented PCO by generating ROS and intracellular ferroptosis.

Dual-responsive nanoplatform for integrated cancer diagnosis and therapy: Unleashing the power of tumor microenvironment

Chemodynamic therapy (CDT), designed to trigger a tumor-specific hydrogen peroxide (H2O2) reaction generating highly toxic hydroxyl radicals (·OH), has been investigated for cancer treatment. Unfortunately, the limited Fenton or Fenton-like reaction rate and the significant impact of excessive reducing glutathione (GSH) in the tumor microenvironment (TME) have severely compromised the effectiveness of CDT. To address this issue, we designed a dual-responsive nanoplatform utilizing a metal-polyphenol network (MPN) -coated multi-caged IrOx for efficient anti-tumor therapy in response to the acidic TME and intracellular excess of GSH, in which MPN composed of Fe3+ and tannic acid (TA). Initially, the acidic TME and intracellular excess of GSH lead to the degradation of the MPN shell, resulting in the release of Fe3+ and exposure of the IrOx core, facilitating the efficient dual-pathway CDT. Subsequently, the nanoplatform can mitigate the attenuation of CDT by consuming the excessive GSH within the tumor. Finally, the multi-caged structure of IrOx is advantageous for effectively implementing photothermal therapy (PTT) in coordination with CDT, further enhancing the therapeutic efficacy of tumors. Moreover, the outstanding Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) (T1/T2) multimodal imaging capabilities of IrOx@MPN enable early diagnosis and timely treatment. This work provides a typical example of the construction of a novel multifunctional platform for dual-responsive treatment of tumors.

Bioactive Nanoliposomes for Enhanced Sonodynamic-Triggered Disulfidptosis-Like Cancer Cell Death via Lipid Peroxidation

Introduction

Cell death regulation holds a unique value in the field of cancer therapy. Recently, disulfidptosis has garnered substantial scientific attention. Previous studies have reported that sonodynamic therapy (SDT) based on reactive oxygen species (ROS) can regulate cancer cell death, achieving an limited anti-cancer effect. However, the integration of SDT with disulfidptosis as an anti-cancer strategy has not been extensively developed. In this study, we constructed an artificial membrane disulfidptosis sonosensitizer, specifically, a nanoliposome (SC@lip) coated with a combination of the chemotherapy medicine Sorafenib (Sora) and sonosensitizer Chlorin e6 (Ce6), to realize a one-stop enhanced SDT effect that induces disulfidptosis-like cancer cell death.

Methods

Sorafenib and Ce6 were co-encapsulated into PEG-modified liposomes, and SC@Lip was constructed using a simple rotary evaporation phacoemulsification method. The cell phagocytosis, ROS generation ability, glutathione (GSH) depletion ability, lipid peroxidation (LPO), and disulfidptosis-like death mediated by SC@Lip under ultrasound (US) irradiation were evaluated. Based on a 4T1 subcutaneous tumor model, both the in vivo biological safety assessment and the efficacy of SDT were assessed.

Results

SC@Lip exhibits high efficiency in cellular phagocytosis. After being endocytosed by 4T1 cells, abundant ROS were produced under SDT activation, and the cell survival rates were below 5%. When applied to a 4T1 subcutaneous tumor model, the enhanced SDT mediated by SC@Lip inhibited tumor growth and prolonged the survival time of mice. In vitro and in vivo experiments show that SC@Lip can enhance the SDT effect and trigger disulfidptosis-like cancer cell death, thus achieving anti-tumor efficacy both in vitro and in vivo.

Conclusion

SC@Lip is a multifunctional nanoplatform with an artificial membrane, which can integrate the functions of sonosensitization and GSH depletion into a biocompatible nanoplatform, and can be used to enhance the SDT effect and promote disulfidptosis-like cancer cell death.

A ferroptosis amplifier based on triple-enhanced lipid peroxides accumulation strategy for effective pancreatic cancer therapy

As an iron dependent regulatory cell death process driven by excessive lipid peroxides (LPO), ferroptosis is recognized as a powerful weapon for pancreatic cancer (PC) therapy. However, the tumor microenvironment (TME) with hypoxia and elevated glutathione (GSH) expression not only inhibits LPO production, but also induces glutathione peroxidase 4 (GPX4) mediated LPO clearance, which greatly compromise the therapeutic outcomes of ferroptosis. To address these issues, herein, a novel triple-enhanced ferroptosis amplifier (denoted as Zal@HM-PTBC) is rationally designed. After intravenous injection, the overexpressed H2O2/GSH in TME induces the collapse of Zal@HM-PTBC and triggers the production of oxygen and reactive oxygen species (ROS), which synergistically amplify the degree of lipid peroxidation (broaden sources). Concurrently, GSH consumption because of the degradation of the hollow manganese dioxide (HM) significantly weakens the activity of GPX4, resulting in a decrease in LPO clearance (reduce expenditure). Moreover, the loading and site-directed release of zalcitabine further promotes autophagy-dependent LPO accumulation (enhance effectiveness). Both in vitro and in vivo results validated that the ferroptosis amplifier demonstrated superior specificity and favorable therapeutic responses. Overall, this triple-enhanced LPO accumulation strategy demonstrates the ability to facilitate the efficacy of ferroptosis, injecting vigorous vitality into the treatment of PC.

Human Serum Albumin Mediated Controllable Synthesis of Defect-Rich Copper Hydroxide Nanowire for Cuproptosis-Based Anti-Tumor Therapy

Cuproptosis, as a newly identified form of programmed cell death, shows great promise in cancer treatment. Efficient Cu+ delivery while avoiding systemic toxicity and elimination of the resistance from over-expressed intracellular copper chelator glutathione (GSH) are critical for cuproptosis. Herein, this work innovatively constructs a biocompatible and defect-rich copper hydroxide nanowire (HCu nanowire) through a human serum albumin (HSA) mediated biomineralization method. This work finds that the morphology and size of HCu nanowires can be controlled adjusted by the feed ratio of HSA and Cu2+. Remarkably, except for outstanding biocompatibility, HSA coordination endows HCu nanowires abundant oxygen vacancies (OVs), and the defect-rich HCu nanowire possesses excellent GSH consumption efficiency. Density functional theory studies indicate that OVs change GSH absorption energy on defective HCu nanowires. In cancer cells, HCu nanowires deplete GSH and simultaneously produce sufficient free Cu+ for enhanced cuproptosis. Meanwhile, Cu+ can catalyze endogenous H2O2 into hydroxyl radicals (·OH) via a Fenton-like reaction. Thus, synergetic cuproptosis and ROS mediated apoptosis against tumor are achieved. The experimental results show that HCu nanowires have a better performance in both antitumor efficiency and safety compared with chemotherapeutic drug Dox at the same dose, demonstrating its great potential in clinical applications.

Near Infrared-Fluorescent Dinuclear Iridium(III) Nanoparticles for Immunogenic Sonodynamic Therapy

Dinuclear iridium(III) complexes activated by light-inducible spatiotemporal control are emerging as promising candidates for cancer therapy. However, broader applications of current light-activated dinuclear iridium(III) complexes are limited by the ineffective tissue penetration and undesirable feedback on guidance activation. Here, an ultrasound (US) triggered near infrared-fluorescent dinuclear iridium(III) nanoparticle, NanoIr, is first reported to precisely and spatiotemporally inhibit tumor growth. It is demonstrated that reactive oxygen species can be generated by NanoIr upon exposure to US irradiation (NanoIr + US), thereby inducing immunogenic cell death. When combined with cisplatin, NanoIr + US elicits synergistic effects in patient-derived tumor xenograft mice models of ovarian cancer. This work first provides a design of dinuclear iridium(III) nanoparticles for immunogenic sonodynamic therapy.

Inhibition of the p62-Nrf2-GPX4 Pathway Confers Sensitivity to Butachlor-Induced Splenic Macrophage Ferroptosis

Butachlor is widely used in agriculture around the world and therefore poses environmental and public health hazards due to persistent and poor biodegradability. Ferroptosis is a type of iron-mediated cell death controlled by glutathione (GSH) and GPX4 inhibition. P62 is an essential autophagy adaptor that regulates Keap1 to activate nuclear factor erythroid 2-related factor 2 (Nrf2), which effectively suppresses lipid peroxidation, thereby relieving ferroptosis. Here, we found that butachlor caused changes in splenic macrophage structure, especially impaired mitochondrial morphology with disordered structure, which is suggestive of the occurrence of ferroptosis. This was further confirmed by the detection of iron metabolism, the GSH system, and lipid peroxidation. Mechanistically, butachlor suppressed the protein level of p62 and promoted Keap1-mediated degradation of Nrf2, which results in decreased GPX4 expression and accelerated splenic macrophage ferroptosis. These findings suggest that targeting the p62-Nrf2-GPX4 signaling axis may be a promising strategy for treating inflammatory diseases.

Ultrasound-Based Micro-/Nanosystems for Biomedical Applications

Due to the intrinsic non-invasive nature, cost-effectiveness, high safety, and real-time capabilities, besides diagnostic imaging, ultrasound as a typical mechanical wave has been extensively developed as a physical tool for versatile biomedical applications. Especially, the prosperity of nanotechnology and nanomedicine invigorates the landscape of ultrasound-based medicine. The unprecedented surge in research enthusiasm and dedicated efforts have led to a mass of multifunctional micro-/nanosystems being applied in ultrasound biomedicine, facilitating precise diagnosis, effective treatment, and personalized theranostics. The effective deployment of versatile ultrasound-based micro-/nanosystems in biomedical applications is rooted in a profound understanding of the relationship among composition, structure, property, bioactivity, application, and performance. In this comprehensive review, we elaborate on the general principles regarding the design, synthesis, functionalization, and optimization of ultrasound-based micro-/nanosystems for abundant biomedical applications. In particular, recent advancements in ultrasound-based micro-/nanosystems for diagnostic imaging are meticulously summarized. Furthermore, we systematically elucidate state-of-the-art studies concerning recent progress in ultrasound-based micro-/nanosystems for therapeutic applications targeting various pathological abnormalities including cancer, bacterial infection, brain diseases, cardiovascular diseases, and metabolic diseases. Finally, we conclude and provide an outlook on this research field with an in-depth discussion of the challenges faced and future developments for further extensive clinical translation and application.

Lipid Nanoparticular Codelivery System for Enhanced Antitumor Effects by Ferroptosis-Apoptosis Synergistic with Programmed Cell Death-Ligand 1 Downregulation

Intrinsic or acquired resistance to chemical drugs severely limits their therapeutic efficacy in cancer treatment. Various intracellular antioxidant molecules, particularly glutathione (GSH), play a crucial role in maintaining intracellular redox homeostasis by mitigating the overproduced reactive oxygen species (ROS) due to rapid cell proliferation. Notably, these antioxidants also eliminate chemical-drug-induced ROS, eventually diminishing their cytotoxicity and rendering them less effective. In this study, we combined erastin, a GSH biosynthesis inhibitor, with 2'-deoxy-5-fluorouridine 5'-monophosphate sodium salt (FdUMP), an ROS-based drug, to effectively disrupt intracellular redox homeostasis and reverse chemotherapy resistance. Therefore, efficient ferroptosis and apoptosis were simultaneously induced for enhanced antitumor effects. Additionally, we employed small interfering RNA targeting PD-L1 (siPD-L1) as a third agent to block immune-checkpoint recognition by CD8+ T cells. The highly immunogenic cell peroxidates or damage-associated molecular patterns (DAMPs) induced by erastin acted synergistically with downregulated PD-L1 to enhance the antitumor effects. To codeliver these three drugs simultaneously and efficiently, we designed GE11 peptide-modified lipid nanoparticles (LNPs) containing calcium phosphate cores to achieve high encapsulation efficiencies. In vitro studies verified its enhanced cytotoxicity, efficient intracellular ROS induction and GSH/GPX4 downregulation, substantial lipid peroxidation product accumulation, and mitochondrial depolarization. In vivo, this formulation effectively accumulated at tumor sites and achieved significant tumor inhibition in subcutaneous colon cancer (CRC) mouse models with a maximum tumor inhibition rate of 83.89% at a relatively low dose. Overall, a strategy to overcome clinical drug resistance was verified in this study by depleting GSH and activating adaptive immunity.

Ferrous sulfate combined with ultrasound emulsified cinnamaldehyde nanoemulsion to cause ferroptosis in Escherichia coli O157:H7

The purpose of this study was to investigate ferroptosis in Escherichia coli O157:H7 caused by ferrous sulfate (FeSO4) and to examine the synergistic effectiveness of FeSO4 combined with ultrasound-emulsified cinnamaldehyde nanoemulsion (CALNO) on inactivation of E. coli O157:H7 in vitro and in vivo. The results showed that FeSO4 could cause ferroptosis in E. coli O157:H7 via generating reactive oxygen species (ROS) and exacerbating lipid peroxidation. In addition, the results indicated that FeSO4 combined with CALNO had synergistic bactericidal effect against E. coli O157:H7 and the combined treatment could lead considerable nucleic acids and protein to release by damaging the cell membrane of E. coli O157:H7. Besides, FeSO4 combined with CALNO had a strong antibiofilm ability to inhibit E. coli O157:H7 biofilm formation by reducing the expression of genes related on biofilm formation. Finally, FeSO4 combined with CALNO exhibited the significant antibacterial activity against E. coli O157:H7 in hami melon and cherry tomato.

Lactic acid responsive sequential production of hydrogen peroxide and consumption of glutathione for enhanced ferroptosis tumor therapy

Ferroptosis is characterized by the lethal accumulation of lipid reactive oxygen species (ROS), which has great potential for tumor therapy. However, developing new ferroptosis-inducing strategies by combining nanomaterials with small molecule inducers is important. In this study, an enzyme-gated biodegradable natural-product delivery system based on lactate oxidase (LOD)-gated biodegradable iridium (Ir)-doped hollow mesoporous organosilica nanoparticles (HMONs) loaded with honokiol (HNK) (HNK@Ir-HMONs-LOD, HIHL) is designed to enhance ferroptosis in colon tumor therapy. After reaching the tumor microenvironment, the outer LOD dissociates and releases the HNK to induce ferroptosis. Moreover, the released dopant Ir4+ and disulfide-bridged organosilica frameworks deplete intracellular glutathione (GSH), which is followed by GSH-mediated Ir(IV)/Ir(III) conversion. This leads to the repression of glutathione peroxidase 4 (GPX4) activity and decomposition of intratumoral hydrogen peroxide (H2O2) into hydroxyl radicals (•OH) by Ir3+-mediated Fenton-like reactions. Moreover, LOD efficiently depletes lactic acid to facilitate the generation of H2O2 and boost the Fenton reaction, which in turn enhances ROS generation. With the synergistic effects of these cascade reactions and the release of HNK, notable ferroptosis efficacy was observed both in vitro and in vivo. This combination of natural product-induced and lactic acid-responsive sequential production of H2O2 as well as the consumption of glutathione may provide a new paradigm for achieving effective ferroptosis-based cancer therapy.

Bimetallic Cu@Ru Core-Shell Structures with Ligand Effects for Endo-Exogenous Stimulation-Mediated Dynamic Oncotherapy

Dynamic therapies, which induce reactive oxygen species (ROS) production in situ through endogenous and exogenous stimulation, are emerging as attractive options for tumor treatment. However, the complexity of the tumor substantially limits the efficacy of individual stimulus-triggered dynamic therapy. Herein, bimetallic copper and ruthenium (Cu@Ru) core-shell nanoparticles are applied for endo-exogenous stimulation-triggered dynamic therapy. The electronic structure of Cu@Ru is regulated through the ligand effects to improve the adsorption level for small molecules, such as water and oxygen. The core-shell heterojunction interface can rapidly separate electron-hole pairs generated by ultrasound and light stimulation, which initiate reactions with adsorbed small molecules, thus enhancing ROS generation. This synergistically complements tumor treatment together with ROS from endogenous stimulation. In vitro and in vivo experiments demonstrate that Cu@Ru nanoparticles can induce tumor cell apoptosis and ferroptosis through generated ROS. This study provides a new paradigm for endo-exogenous stimulation-based synergistic tumor treatment.

Photothermal and ferroptosis synergistic therapy for liver cancer using iron-doped polydopamine nanozymes

An innovative nanozyme, iron-doped polydopamine (Fe-PDA), which integrates iron ions into a PDA matrix, conferred peroxidase-mimetic activity and achieved a substantial photothermal conversion efficiency of 43.5 %. Fe-PDA mediated the catalysis of H2O2 to produce toxic hydroxyl radicals (•OH), thereby facilitating lipid peroxidation in tumour cells and inducing ferroptosis. Downregulation of solute carrier family 7 no. 11 (SLC7A11) and solute carrier family 3 no. 2 (SLC3A2) in System Xc- resulted in decreased intracellular glutathione (GSH) production and inactivation of the nuclear factor erythroid 2-related factor 2 (NRF2)-glutathione peroxidase 4 (GPX4) pathway, contributing to ferroptosis. Moreover, the application of photothermal therapy (PTT) enhanced the effectiveness of chemodynamic therapy (CDT), accelerating the Fenton reaction for targeted tumour eradication while sparing adjacent non-cancerous tissues. In vivo experiments revealed that Fe-PDA significantly hampered tumour progression in mice, emphasizing the potential of the dual-modality treatment combining CDT and PTT for future clinical oncology applications.

Metal-Organic Framework-Based Nanomedicines for Ferroptotic Cancer Therapy

As an iron-dependent, non-apoptosis, regulated cell death (RCD) modality, ferroptosis has gained growing attention for cancer therapy. With the development of nanomaterials in the biomedical field, ferroptotic cancer nanomedicine is extensively investigated. Amongst various nanomaterials, metal-organic frameworks (MOFs) are hybridized porous materials consisting of metal ions or clusters bridged by organic linkers. The superior properties of MOFs, such as high porosity and cargo loading, ease of surface modification, and good biocompatibility, make them appealing in inducing or sensitizing ferroptotic cell death. There are remarkable achievements in the field of MOF-based ferroptosis cancer therapy. However, this topic is not reviewed. This review will introduce the fundamentals of MOF and ferroptosis machinery, summarize the recent progress of MOF-based ferroptotic anticancer drug delivery, discuss the benefits and problems of MOFs as vehicles and sensitizers for cancer ferroptosis, and provide the perspective on future research direction on this promising field.

Dual-Responsive hollow mesoporous organosilicon nanocarriers for photodynamic therapy

HYPOTHESIS

The nano-delivery platform, -SS-HMONs@MB@MnO2 nanoparticles (SMM NPs) loaded with methylene blue (MB) as photosensitizer have excellent photodynamic therapy (PDT) effect. The disulfide bond and MnO2 give the shell redox-responsive properties. SMM NPs consume glutathione (GSH) in tumor cells, reducing the scavenging of reactive oxygen species (ROS) by GSH and enhancing the PDT effect of MB.

EXPERIMENTS

The GSH dual-responsive nano-delivery platform, was designed and constructed by using disulfide-doped hollow mesoporous organosilicon nanoparticles (-SS-HMONs) as intermediate responsive layer, loaded with MB as photosensitizer and coated with MnO2 as shells. The MB photosensitizer release and GSH response were characterized. The PDT effect of nanoparticles was evaluated.

FINDINGS

The SMM NPs were uniform in size and well dispersed. The nanoparticles could react with GSH, leading to the decomposition of MnO2 shells and the breakage of disulfide bonds in -SS-HMONs, resulted in the release of MB photosensitizer. The cell experiment showed that SMM NPs had good ROS generating ability and PDT effect after being sucked by tumor cells, which could effectively kill tumor cells. However, in vivo experiments demonstrated that SMM NPs showed slight inhibition on tumor growth. The actual effect in animals was different from the effect in cells.

Nanomaterials-Induced Redox Imbalance: Challenged and Opportunities for Nanomaterials in Cancer Therapy

Cancer cells typically display redox imbalance compared with normal cells due to increased metabolic rate, accumulated mitochondrial dysfunction, elevated cell signaling, and accelerated peroxisomal activities. This redox imbalance may regulate gene expression, alter protein stability, and modulate existing cellular programs, resulting in inefficient treatment modalities. Therapeutic strategies targeting intra- or extracellular redox states of cancer cells at varying state of progression may trigger programmed cell death if exceeded a certain threshold, enabling therapeutic selectivity and overcoming cancer resistance to radiotherapy and chemotherapy. Nanotechnology provides new opportunities for modulating redox state in cancer cells due to their excellent designability and high reactivity. Various nanomaterials are widely researched to enhance highly reactive substances (free radicals) production, disrupt the endogenous antioxidant defense systems, or both. Here, the physiological features of redox imbalance in cancer cells are described and the challenges in modulating redox state in cancer cells are illustrated. Then, nanomaterials that regulate redox imbalance are classified and elaborated upon based on their ability to target redox regulations. Finally, the future perspectives in this field are proposed. It is hoped this review provides guidance for the design of nanomaterials-based approaches involving modulating intra- or extracellular redox states for cancer therapy, especially for cancers resistant to radiotherapy or chemotherapy, etc.

Advances in Ferroptosis-Inducing Agents by Targeted Delivery System in Cancer Therapy

Currently, cancer remains one of the most significant threats to human health. Treatment of most cancers remains challenging, despite the implementation of diverse therapies in clinical practice. In recent years, research on the mechanism of ferroptosis has presented novel perspectives for cancer treatment. Ferroptosis is a regulated cell death process caused by lipid peroxidation of membrane unsaturated fatty acids catalyzed by iron ions. The rapid development of bio-nanotechnology has generated considerable interest in exploiting iron-induced cell death as a new therapeutic target against cancer. This article provides a comprehensive overview of recent advancements at the intersection of iron-induced cell death and bionanotechnology. In this respect, the mechanism of iron-induced cell death and its relation to cancer are summarized. Furthermore, the feasibility of a nano-drug delivery system based on iron-induced cell death for cancer treatment is introduced and analyzed. Secondly, strategies for inducing iron-induced cell death using nanodrug delivery technology are discussed, including promoting Fenton reactions, inhibiting glutathione peroxidase 4, reducing low glutathione levels, and inhibiting system Xc-. Additionally, the article explores the potential of combined treatment strategies involving iron-induced cell death and bionanotechnology. Finally, the application prospects and challenges of iron-induced nanoagents for cancer treatment are discussed.

Tumor microenviroment-responsive self-assembly of barium titanate nanoparticles with enhanced piezoelectric catalysis capabilities for efficient tumor therapy

Catalytic therapy based on piezoelectric nanoparticles has become one of the effective strategies to eliminate tumors. However, it is still a challenge to improve the tumor delivery efficiency of piezoelectric nanoparticles, so that they can penetrate normal tissues while specifically aggregating at tumor sites and subsequently generating large amounts of reactive oxygen species (ROS) to achieve precise and efficient tumor clearance. In the present study, we successfully fabricated tumor microenvironment-responsive assembled barium titanate nanoparticles (tma-BTO NPs): in the neutral pH environment of normal tissues, tma-BTO NPs were monodisperse and possessed the ability to cross the intercellular space; whereas, the acidic environment of the tumor triggered the self-assembly of tma-BTO NPs to form submicron-scale aggregates, and deposited in the tumor microenvironment. The self-assembled tma-BTO NPs not only caused mechanical damage to tumor cells; more interestingly, they also exhibited enhanced piezoelectric catalytic efficiency and produced more ROS than monodisperse nanoparticles under ultrasonic excitation, attributed to the mutual extrusion of neighboring particles within the confined space of the assembly. tma-BTO NPs exhibited differential cytotoxicity against tumor cells and normal cells, and the stronger piezoelectric catalysis and mechanical damage induced by the assemblies resulted in significant apoptosis of mouse breast cancer cells (4T1); while there was little damage to mouse embryo osteoblast precursor cells (MC3T3-E1) under the same treatment conditions. Animal experiments confirmed that peritumoral injection of tma-BTO NPs combined with ultrasound therapy can effectively inhibit tumor progression non-invasively. The tumor microenvironment-responsive self-assembly strategy opens up new perspectives for future precise piezoelectric-catalyzed tumor therapy.

A Lysosome-Targeted Magnetic Nanotorquer Mechanically Triggers Ferroptosis for Breast Cancer Treatment

Targeting ferroptosis has attracted exponential attention to eradicate cancer cells with high iron-dependent growth. Increasing the level of intracellular labile iron pool via small molecules and iron-containing nanomaterials is an effective approach to induce ferroptosis but often faces insufficient efficacy due to the fast drug metabolism and toxicity issues on normal tissues. Therefore, developing a long-acting and selective approach to regulate ferroptosis is highly demanded in cancer treatment. Herein, a lysosome-targeted magnetic nanotorquer (T7-MNT) is proposed as the mechanical tool to dynamically induce the endogenous Fe2+ pool outbreak for ferroptosis of breast cancer. T7-MNTs target lysosomes via the transferrin receptor-mediated endocytosis in breast cancer cells. Under the programmed rotating magnetic field, T7-MNTs generate torques to trigger endogenous Fe2+ release by disrupting the lysosomal membrane. This magneto-mechanical manipulation can induce oxidative damage and antioxidant defense imbalance to boost frequency- and time-dependent lipid peroxidization. Importantly, in vivo studies show that T7-MNTs can efficiently trigger ferroptosis under the magnetic field and play as a long-acting physical inducer to boost ferrotherapy efficacy in combination with RSL3. It is anticipated that this dynamic targeted strategy can be coupled with current ferroptosis inducers to achieve enhanced efficacy and inspire the design of mechanical-based ferroptosis inducers for cancer treatment.

Defect engineering to tailor structure-activity relationship in biodegradable nanozymes for tumor therapy by dual-channel death strategies

Pursuing biodegradable nanozymes capable of equipping structure-activity relationship provides new perspectives for tumor-specific therapy. A rapidly degradable nanozymes can address biosecurity concerns. However, it may also reduce the functional stability required for sustaining therapeutic activity. Herein, the defect engineering strategy is employed to fabricate Pt-doping MoOx (PMO) redox nanozymes with rapidly degradable characteristics, and then the PLGA-assembled PMO (PLGA@PMO) by microfluidics chip can settle the conflict between sustaining therapeutic activity and rapid degradability. Density functional theory describes that Pt-doping enables PMO nanozymes to exhibit an excellent multienzyme-mimicking catalytic activity originating from synergistic catalysis center construction with the interaction of Pt substitution and oxygen vacancy defects. The peroxidase- (POD), oxidase- (OXD), glutathione peroxidase- (GSH-Px), and catalase- (CAT) mimicking activities can induce robust ROS output and endogenous glutathione depletion under tumor microenvironment (TME) response, thereby causing ferroptosis in tumor cells by the accumulation of lipid peroxide and inactivation of glutathione peroxidase 4. Due to the activated surface plasmon resonance effect, the PMO nanozymes can cause hyperthermia-induced apoptosis through 1064 nm laser irradiation, and augment multienzyme-mimicking catalytic activity. This work represents a potential biological application for the development of therapeutic strategy for dual-channel death via hyperthermia-augmented enzyme-mimicking nanocatalytic therapy.

Nanomedicine/materdicine-enabled sonocatalytic therapy

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

Recent Progress in Ferroptosis Induced Tumor Cell Death by Anti-tumor Metallic complexes

Metal complexes represented by platinum complexes play a very important role in cancer treatment due to their diverse chemical structures and anti-tumor activities. Recently, ferroptosis has emerged as a newly occurring cell death form in the anti-tumor process. It has been reported that metal complexes could inhibit the proliferation and metastasis of tumors and combat chemotherapy resistance by targeting ferroptosis. In this review, we briefly describe ferroptosis as a fundamental process for tumor suppression and triggering anti-tumor immune responses. We summarize recent developments on metal complexes that induce ferroptosis. Finally, we outline the prospects for the application of metal complexes to the treatment of tumors based on ferroptosis and the associated problems that need to be solved, and discussed other potential research directions of metal complexes.

Self‐Reliant Nanomedicine with Long‐Lasting Glutathione Depletion Ability Disrupts Adaptive Redox Homeostasis and Suppresses Cancer Stem Cells

Bulk cancer cells and cancer stem cells (CSCs) harbor efficient and adaptive redox systems to help them resist oxidative insults arising from diverse therapeutic modalities. Herein, a tumor microenvironment (TME)‐activatable nano‐modulator capable of disrupting adaptive redox homeostasis, prepared by integrating FDA‐approved xCT inhibitor sulfasalazine (SSZ) into pH‐responsive hydroxyethyl starch‐doxorubicin conjugate stabilized copper peroxide nanoparticles (HSCPs) is reported. Compared to poly(vinylpyrrolidone) (PVP)‐stabilized copper peroxide nanoparticles, HSCPs exhibit superior physiological stability, longer circulation half‐life, and higher tumor enrichment. Under an acidic TME, the active components inside HSCPs are productively released along with the disintegration of HSCPs. The specifically generated hydrogen peroxide (H2O2) from copper peroxide nanoparticles furnishes a constant power source for copper‐mediated hydroxyl radical (•OH) production, serving as a wealthy supplier for oxidative stress. Meanwhile, the tumor‐specific release of Cu2+ and SSZ can induce long‐lasting glutathione (GSH) depletion via copper‐mediated self‐cycling valence transitions and SSZ‐blocked GSH biosynthesis, thereby reducing the offsetting action of the antioxidant GSH against oxidative stress. As a result, this sustained oxidative stress potently restrains the growth of aggressive orthotopic breast tumors while suppressing pulmonary metastasis by eradicating CSC populations. The reported smart nanomedicine provides a new paradigm for redox imbalance‐triggered cancer therapy.

Interfacial strong interaction-enabling cascade nanozymes for apoptosis-ferroptosis synergistic therapy

Noble metal nanozymes are promising therapeutic agents due to their good ability of reactive oxygen species generation in response to the tumor microenvironment (TME). Achieving optimal performance of noble metal nanozymes at a minimum dosage is crucial due to potential systemic biotoxicity. In this study, we report the successful anchoring of Ir nanoclusters on Co(OH)2 nanosheets with an Ir content of 6.2 wt% (denoted as Ir6.2-Co(OH)2), which exhibits remarkable peroxidase (POD)- and catalase (CAT)-like activities. The strong electronic interaction at the Ir-O-Co interface endows glutathione peroxidase (GSH-Px)-like activity to the composite, ensuring efficient generation of reactive oxygen species (ROS) and deactivation of glutathione peroxidase 4 (GPX4) by supplementing hydrogen peroxide (H2O2) and depleting glutathione (GSH). Both in vitro and in vivo evaluations demonstrate that Ir6.2-Co(OH)2 nanozymes significantly enhance antitumor efficacy through apoptosis-ferroptosis synergistic therapy. This study highlights the tremendous potential of leveraging strong electronic interactions between noble metals and oxides for modulating enzyme-like activities towards high-efficiency synergistic therapies.

Sonocatalytic cancer therapy: theories, advanced catalysts and system design

Treating cancer remains one of the most formidable challenges in modern medicine, with traditional treatment options often being limited by poor therapeutic outcomes and unacceptable side effects. Nanocatalytic therapy activates tumor-localized catalytic reactions in situ via nontoxic or minimally toxic nanocatalysts responding to unique cues from the tumor microenvironment or external stimuli. In particular, sonocatalytic cancer therapy is a promising approach that has emerged as a potential solution to this problem through the combination of ultrasound waves and catalytic materials to selectively target and destroy cancer cells. Compared to light, ultrasound exhibits higher spatial precision, lower energy attenuation, and superior tissue penetrability, furnishing more energy to catalysts. Multidimensional modulation of nanocatalyst structures and properties is pivotal to maximizing catalytic efficiency given constraints in external stimulative energy as well as substrate types and levels. In this review, we discuss the various theories and mechanisms underlying sonocatalytic cancer therapy, as well as advanced catalysts that have been developed for this application. Additionally, we explore the design of sonocatalytic cancer therapy systems, including the use of heterojunction catalysts and the optimal conditions for achieving maximum therapeutic effects. Finally, we highlight the potential benefits of sonocatalytic cancer therapy over traditional cancer treatments, including its noninvasive nature and lower toxicity.

Trisulfide Bond-Mediated Molecular Phototheranostic Platform for "Activatable" NIR-II Imaging-Guided Enhanced Gas/Chemo-Hypothermal Photothermal Therapy

Tumor microenvironment (TME)-triggered phototheranostic platform offers a feasible strategy to improve cancer diagnosis accuracy and minimize treatment side effects. Developing a stable and biocompatible molecular phototheranostic platform for TME-activated second near-infrared (NIR-II) fluorescence imaging-guided multimodal cascade therapy is a promising strategy for creating desirable anticancer agents. Herein, a new NIR-II fluorescence imaging-guided activatable molecular phototheranostic platform (IR-FEP-RGD-S-S-S-Fc) is presented for actively targeted tumor imaging and hydrogen sulfide (H2 S) gas-enhanced chemodynamic-hypothermal photothermal combined therapy (CDT/HPTT). It is revealed for the first time that the coupling distance between IR-FE and ferrocene is proportional to the photoinduced electron transfer (PET), and the aqueous environment is favorable for PET generation. The part of Cyclic-RGDfK (cRGDfk) peptides can target the tumor and benefit the endocytosis of nanoparticles. The high-concentration glutathione (GSH) in the TME will separate the fluorescence molecule and ferrocene by the GSH-sensitive trisulfide bond, realizing light-up NIR-II fluorescence imaging and a cascade of trimodal synergistic CDT/HPTT/gas therapy (GT). In addition, the accumulation of hydroxyl radicals (•OH) and down-regulation of glutathione peroxidase 4 (GPX4) can produce excessive harmful lipid hydroperoxides, ultimately leading to ferroptosis.

Optimized strategies of ROS-based nanodynamic therapies for tumor theranostics

Reactive oxygen species (ROS) play a crucial role in regulating the metabolism of tumor growth, metastasis, death and other biological processes. ROS-based nanodynamic therapies (NDTs) are becoming attractive due to non-invasive, low side effects and tumor-specific advantages. NDTs have rapidly developed into numerous branches, such as photodynamic therapy, chemodynamic therapy, sonodynamic therapy and so on. However, the complexity of the tumor microenvironment and the limitations of existing sensitizers have greatly restricted the therapeutic effects of NDTs, which heavily rely on ROS levels. To address the limitations of NDTs, various strategies have been developed to increase ROS yield, which is an urgent aspect for the positive development of NDTs. In this review, the nanodynamic potentiation strategies in terms of unique properties and universalities of NDTs are comprehensively outlined. We mainly summarize the current dilemmas faced by each NDT and the respective solutions. Meanwhile, the NDTs universalities-based potentiation strategies and NDTs-based combined treatments are elaborated. Finally, we conclude with a discussion of the key issues and challenges faced in the development and clinical transformation of NDTs.

Redox-active polyphenol nanoparticles deprive endogenous glutathione of electrons for ROS generation and tumor chemodynamic therapy

Chemodynamic therapy (CDT) based on generating reactive oxygen species (ROS) is promising for cancer treatment. However, the intrinsic H2O2 is deficient for CDT, and glutathione (GSH) eliminates ROS to protect tumor cells from ROS cytotoxicity. Herein, we propose a strategy to switch the electron flow direction of GSH for O2 reduction and ROS generation rather than ROS clearance by using P(DA-Fc) nanoparticles, which are polymerized from ferrocenecarboxylic acid (Fc) coupled dopamine. P(DA-Fc) NPs with phenol-quinone conversion ability mimic NOX enzyme to deprive electrons from GSH to reduce O2 for H2O2 generation; the following •OH release can be triggered by Fc. Semiquinone radicals in P(DA-Fc) are significantly enhanced after GSH treatment, further demonstrated with strong single-electron reduction ability by calculation. In vitro and in vivo experiments indicate that P(DA-Fc) can consume intrinsic GSH to produce endogenous ROS; ROS generation strongly depends on GSH/pH level and eventually causes tumor cell death. Our work makes the first attempt to reverse the function of GSH from ROS scavenger to ROS producer, explores new roles of PDA-based nanomaterials in CDT beyond photothermal reagents and drug carriers, and provides a new strategy to improve the efficiency of CDT. STATEMENT OF SIGNIFICANCE: P(DA-Fc) nanoparticles performing tumor microenvironment response capacity and tumor reductive power utilize ability were fabricated for CDT tumor suppression. After endocytosis by tumor cells, P(DA-Fc) deprived GSH of electrons for H2O2 and •OH release, mimicking the intrinsic ROS production conducted by NADPH, further inducing tumor cell necrosis and apoptosis. Our work makes the first attempt to reverse the function of GSH from ROS scavenger to producer, explores new functions of PDA-based nanomaterials in CDT beyond photothermal reagents and drug carriers, and provides a new strategy to improve CDT efficiency.

Superoxide Dismutase-Like Regulated Fe/Ppa@PDA/B for Synergistically Targeting Ferroptosis/Apoptosis to Enhance Anti-Tumor Efficacy

The cell apoptosis pathway of sonodynamic therapy (SDT) is usually blocked, resulting in limited therapeutic efficacy, therefore, the development of new methods for sensitizing targeted ferroptosis and promoting apoptosis is of great significance to improve the anti-tumor efficacy of SDT. Herein, mesoporous Fe3 O4 nanoparticles (NPs) are synthesized for loading pyropheophorbide-a (ppa), surface-coated by polydopamine (PDA) and further anchored with tumor-targeting moieties of biotin to obtain Fe/ppa@PDA/B NPs. Fe/ppa@PDA/B displayes pH/ultrasound (US) responsive release properties, and magnetic resonance imaging (MRI) functions. Moreover, Fe3 O4 NPs of Fe/ppa@PDA/B as the Fe source for ferroptosis, enhances ferroptosis sensitivity by consuming glutathione (GSH) and producing hydroxyl radical (OH). The quinone groups of PDA layer on Fe/ppa@PDA/B own free electrons, which led to effective superoxide dismutase (SOD) action through superoxide anion (O2 - ) disproportionation to hydrogen peroxide (H2 O2 ) and oxygen (O2 ), thus, overcame hypoxia of SDT and promoted ·OH generation by Fe ions under US trigger, synergistically improves ferroptosis and apoptosis to enhance the anti-tumor efficacy of SDT both in vitro and in vivo. The anti-tumor strategy of synergistic apoptosis and ferroptosis induce by GSH depletion and self-sufficient O2 regulated by SOD provides a new idea for enhancing SDT efficacy.