Synergistic checkpoint-blockade and radiotherapy–radiodynamic therapy via an immunomodulatory nanoscale metal–organic framework

Emerging nanomedicines for macrophage-mediated cancer therapy

Tumor-associated macrophages (TAMs) contribute to tumor progression by promoting angiogenesis, remodeling the tumor extracellular matrix, inducing tumor invasion and metastasis, as well as immune evasion. Due to the high plasticity of TAMs, they can polarize into different phenotypes with distinct functions, which are primarily categorized as the pro-inflammatory, anti-tumor M1 type, and the anti-inflammatory, pro-tumor M2 type. Notably, anti-tumor macrophages not only directly phagocytize tumor cells, but also present tumor-specific antigens and activate adaptive immunity. Therefore, targeted regulation of TAMs to unleash their potential anti-tumor capabilities is crucial for improving the efficacy of cancer immunotherapy. Nanomedicine serves as a promising vehicle and can inherently interact with TAMs, hence, emerging as a new paradigm in cancer immunotherapy. Due to their controllable structures and properties, nanomedicines offer a plethora of advantages over conventional drugs, thus enhancing the balance between efficacy and toxicity. In this review, we provide an overview of the hallmarks of TAMs and discuss nanomedicines for targeting TAMs with a focus on inhibiting recruitment, depleting and reprogramming TAMs, enhancing phagocytosis, engineering macrophages, as well as targeting TAMs for tumor imaging. We also discuss the challenges and clinical potentials of nanomedicines for targeting TAMs, aiming to advance the exploitation of nanomedicine for cancer immunotherapy.

Fe3O4@Bi2S3 Nanoparticles Mediated MRI-Guided Precision Radiosensitization for Orthotopic Glioblastoma via External Magnetism

Radioresistance in tumors and the excess damage in normal tissues during radiotherapy (RT) restrict the clinical application of glioblastoma RT. Image-guided radiosensitization is hopefully adopted to achieve precision RT. Nevertheless, the therapeutic effect of radiosensitizers in glioblastoma is unsatisfactory due to limitations of the blood-brain barrier and poor tumor targeting. Herein, Fe3O4@Bi2S3 nanoparticles coated with a glioblastoma cell membrane (denoted as FBM) have been designed to sensitize RT. FBM accumulates precisely within the tumors via external magnetism and homologous adhesion capability. Afterward, FBM releases high-Z atoms (Bismuth) in ionizing radiation and tumor micro acidic environments that interact with ionizing radiation to generate high densities of secondary radiation, which leads to enhanced radiation dose deposits. Simultaneously, FBM generates reactive oxygen species, accumulates lipid peroxidation and Fe2+, depletes glutathione, and downregulates glutathione peroxidase 4 to activate ferroptosis. Notably, the tumor growth inhibition rate of FBM-mediated RT via external magnetism increases to 75.49% in the orthotopic glioblastoma model. Besides, FBM with magnetic resonance imaging performance shows the potential application in tumor diagnosis and therapy surveillance, thereby reducing damage to adjacent normal tissues and realizing MRI-guided precision RT. Hence, the novel multifunctional nanoplatform offers the potential for image-guided radiosensitization induced by activating ferroptosis, thus presenting an efficient radiotherapeutic approach for glioblastoma.

Reprogramming Lung Redox Homeostasis by NIR Driven Ultra-Small Pd Loaded Covalent Organic Framework Inhibits NF-κB Pathway for Acute Lung Injury Immunotherapy

Acute lung injury (ALI) refers to damage to lung related cells, typically caused by an uncontrollable inflammatory response, and over-generated reactive oxygen species (ROS). Increasing evidence suggests that reprogramming lung redox homeostasis holds significant potentials for the clinical treatment of ALI. Herein, the simple synthesis of ultra-small Pd loaded covalent organic framework (COF) (TP@Pd) is reported, which, when combined with near infrared (NIR) irradiation, exhibits nanozyme functionalities, including multiple enzyme mimicking activities and broad spectrum ROS scavenging, thereby promoting tissue repair for ALI immunotherapy. Mechanistically, through the therapeutic strategy of TP@Pd+NIR, the damaged cells and tissues are ameliorated by decreasing intracellular ROS levels (total ROS, ·OH and ·O2 -), downregulating inflammatory cytokines levels (IL-6, TNF-α and IL-1β), upregulating antioxidant factor level (SOD2), inducing macrophage M2 directional polarization (downregulation of iNOS and CD86, and upregulation of IL-10 and CD206), activating immunoregulation (CD4+/CD8+ ratio increase), promoting tissue repair factor levels (upregulation of HSP70 and CD31), and suppressing the NF-κB signaling pathway (downregulation of phosphorylated p65 and IκBα). Furthermore, following intravenous (IV) injection in rats, TP@Pd accumulated in lung tissue for 6 h, indicating the promising therapeutic efficacy via this administration route. Notably, the TP@Pd+NIR strategy demonstrated the excellent synergistic effects in alleviating lung inflammation storms, reducing diffuse alveolar damage, and accelerating lung tissue repair. Summarily, this work has designed a novel TP@Pd+NIR strategy for the synergistic enhancement of ALI amelioration, which may serve as a promising therapeutic approach for other ROS related diseases.

Eliminating Radioresistance With a Magnetic Ion-Generator by Simultaneously Augmenting DNA Damage and Diminishing Immunosuppression

Radiotherapy (RT) hinges on DNA damage-induced cancer cell death and the subsequent anti-tumor immunity. However, the efficacy of RT is curtailed by cell cycle heterogeneity and an immunosuppressive tumor microenvironment, which foster radioresistance. Here an ion generator-based RT enhancement strategy is demonstrated in a mouse model of the radioresistant tumor. The ion generator is degraded in the tumor microenvironment, resulting in iron-triggered ferroptosis that enhanced immunogenic cell death and a manganese-activated stimulator of interferon gene that reversed the immunosuppressive environment. As a result, the proposed strategy promotes dendritic cells maturity, augmentes CD8+ T cell infiltration of tumors, suppresses intratumoral myeloid-derived suppressor cells, and limits the M2 macrophages polarization, indicating the formation of an immunoreactive microenvironment. Significantly, this approach impedes the growth of not just primary, but also distal metastatic tumors. It is thus believed that the current ion generator provides a robust and enduring countermeasure to radioresistant cancer and its metastasis, with potential implications for enhancing the efficacy of RT in clinically resistant tumors.

A Pyroptosis Radiosensitizer Facilitates Hypoxic Tumor Necrosis

Hypoxia-related tumor radioresistance markedly impairs the efficacy of radiotherapy. Herein, a targeted radiosensitization strategy is introduced, leveraging the upregulation of gasdermin C (GSDMC) in hypoxic tumor cells, aiming to induce pyroptosis through the application of a cobalt-containing polyoxometalate-based radiosensitizer. This novel radiosensitizer is designed for the precisely controlled release of cobalt ions upon X-ray irradiation, thereby activating caspase-8 and prompting the cleavage of GSDMC. This sequence of events selectively triggers pyroptosis in hypoxic tumor cells, directly addressing radioresistance. The ensuing results highlight the enhanced radiotherapy efficacy and tumor necrosis both in vitro and in vivo models. Overall, the findings confirm the effectiveness of this strategy targeting high GSDMC expression in hypoxic tumors to induce pyroptosis for precise radiotherapy. Such findings encourage further exploration of hypoxia-driven pyroptosis to improve cancer treatment outcomes.

Regulation of cancer-associated fibroblasts for enhanced cancer immunotherapy using advanced functional nanomedicines: an updated review

The tumor microenvironment (TME) is a complex and dynamic ecosystem that plays a critical role in cancer progression. It comprises various cell types, including immune cells, tumor cells, and stromal cells. Among these, cancer-associated fibroblasts (CAFs) represent a heterogeneous population with diverse origins, phenotypes, and functions. Activated CAFs secrete multiple factors that promote tumor growth, migration, angiogenesis, and contribute to chemoresistance. Additionally, CAFs secrete extracellular matrix (ECM) components, such as collagen, which form a physical barrier that hinders the penetration of chemotherapeutic and immunotherapeutic agents. This ECM also influences immune cell infiltration, impeding their ability to effectively target tumor cells. As a result, modulating the activity of CAFs has emerged as a promising strategy to enhance the efficacy of tumor immunotherapy. Nano-delivery systems, constructed from various nanomaterials with high targeting specificity and biocompatibility, offer a compelling approach to deliver therapeutic agents or immunomodulatory factors directly to CAFs. This modulation can alter CAF function, reduce their tumor-promoting effects, and thereby improve the outcomes of immunotherapy. This review provides an in-depth exploration of the origins, functions, and interactions of CAFs within the TME, particularly in the context of immune suppression. Furthermore, it discusses the potential applications of functional nanocarrifers in modulating CAFs and enhancing the effectiveness of tumor immunotherapy, highlighting the significant progress and potential of nanotechnology in this area.

Transferrin-Based Bismuth Nanoparticles for Radiotherapy with Immunomodulation Against Orthotopic Glioma

Modern radiotherapy frequently employs radiosensitizers for radiation dose deposition and triggers an immunomodulatory effect to enhance tumor destruction. However, developing glioma-targeted sensitizers remains challenging due to the blood-brain barrier (BBB) and multicomponent instability. This study aims to green-synthesize transferrin-bismuth nanoparticles (TBNPs) as biosafe radiosensitizers to enhance X-ray absorption by tumors and stimulate the immune response for glioma therapy. The proposed protein-based strategy provides TBNPs with BBB-crossing ability and prevents off-target toxicity. Cellular experiments following 4 Gy of X-ray irradiation reveal that TBNPs increase DNA damage in glioma cells and trigger immunomodulation, thereby inducing immunogenic cell death. Furthermore, TBNPs effectively inhibit tumor growth through synergistic radiotherapy and immunotherapy in an orthotopic glioma mouse model. The findings highlight TBNPs as promising radiosensitizers for effective and biosafe radiotherapy with immunomodulation.

Synthesis and immunotherapy efficacy of a PD-L1 small-molecule inhibitor combined with its 131I-iodide labelled isostructural compound

Although antibody-based immune checkpoint blockades have been successfully used in antitumor immunotherapy, the low response rate is currently the main problem. In this work, a small-molecule programmed cell death-ligand (PD-L1) inhibitor, LG-12, was developed and radiolabeled with 131I to obtain the chemically and biologically identical radiopharmaceutical [131I]LG-12, which aimed to improve the antitumor effect by combination of LG-12 and [131I]LG-12. LG-12 showed high inhibitory activity to PD-1/PD-L1 interaction. The results of cell uptake and biodistribution studies indicated that [131I]LG-12 could specifically bind to PD-L1 in B16-F10 tumors. It could induce immunogenic cell death and the release of high mobility group box 1 and calreticulin. The combination of [131I]LG-12 and LG-12 could significantly inhibit tumor growth and resulted in enhanced antitumor immune response. This PD-L1 small-molecule inhibitor based combination strategy has great potential for tumor treatment.

Real-time detection of gastrointestinal leaks via bismuth chelate-enhanced X-ray gastroenterography

Anastomotic leaks are among the most dreaded complications following gastrointestinal (GI) surgery, and contrast-enhanced X-ray gastroenterography is considered the preferred initial diagnostic method for GI leaks. However, from fundamental research to clinical practice, the only oral iodinated contrast agents currently available for GI leaks detection are facing several challenges, including low sensitivity, iodine allergy, and contraindications in patients with thyroid diseases. Herein, we propose a cinematic contrast-enhanced X-ray gastroenterography for the real-time detection of GI leaks with an iodine-free bismuth chelate (Bi-DTPA) for the first time. The Bi-DTPA, synthesized through a straightforward one-pot method, offers distinct advantages such as no need for purification, a nearly 100 % yield, large-scale production capability, and good biocompatibility. The remarkable X-ray attenuation properties of Bi-DTPA enable real-time dynamic visualization of whole GI tract under both X-ray gastroenterography and computed tomography (CT) imaging. More importantly, the leaky site and severity can be both clearly displayed during Bi-DTPA-enhanced gastroenterography in a rat model with esophageal leakage. The proposed movie-like Bi-DTPA-enhanced X-ray imaging approach presents a promising alternative to traditional GI radiography based on iodinated molecules. It demonstrates significant potential in addressing concerns related to iodine-associated adverse effects and offers an alternative method for visually detecting gastrointestinal leaks.

A cuproptosis nanocapsule for cancer radiotherapy

Residual tumours that persist after radiotherapy often develop acquired radiation resistance, increasing the risk of recurrence and metastasis while providing obstacles to re-irradiation. Using samples from patients and experimental mice, we discovered that FDX1 and LIAS, key regulators of cuproptosis, were up-regulated in residual tumours following radiotherapy, conferring the increased sensitivity to cuproptosis. Therefore, we proposed a novel radiosensitization strategy focused on cuproptosis, using a copper-containing nanocapsule-like polyoxometalate as a paradigm. In an initial demonstration, we showed that the nanocapsule released copper ions in a controlled manner upon exposure to ionizing radiation. Furthermore, radiation-triggered cuproptosis overcame acquired radiation resistance even at clinically relevant radiation doses and activated a robust abscopal effect, with a 40% cure rate in both radioresistant and re-irradiation tumour models. Collectively, targeting cuproptosis is a compelling strategy for addressing acquired radiation resistance, optimizing the local antitumour effects of radiotherapy while simultaneously activating systemic antitumour immunity.

Bimetal-Biligand Frameworks for Spatiotemporal Nitric Oxide-Enhanced Sono-Immunotherapy

Sonodynamic therapy can trigger immunogenic cell death to augment immunotherapy, benefiting from its superior spatiotemporal selectivity and non-invasiveness. However, the practical applications of sonosensitizers are hindered by their low efficacy in killing cancer cells and activating immune responses. Here, two US Food and Drug Administration-approved drug ligands (ferricyanide and nitroprusside) and two types of metals (copper/iron) are selected to construct a bimetal-biligand framework (Cu[PBA-NO]). Through elaborate regulation of multiple metal/ligand coordination, the systemically administered Cu[PBA-NO] nanoagent shows sono-catalytic and NO release ability under ultrasound irradiation, which can be used for effective sono-immunotherapy. Moreover, Cu[PBA-NO] can downregulate intracellular glutathione levels that would destroy intracellular redox homeostasis and facilitate reactive oxygen species accumulation. The released tumor-associated antigens subsequently facilitate dendritic cell maturation within the tumor-draining lymph node, effectively initiating a T cell-mediated immune response and thereby bolstering the capacity to identify and combat cancer cells. This study paves a new avenue for the efficient cancer sono-immunotherapy.

Gold-siRNA supraclusters enhance the anti-tumor immune response of stereotactic ablative radiotherapy at primary and metastatic tumors

Strategies to enhance the anti-tumor immune response of stereotactic ablative radiotherapy (SABR) at primary tumors and abscopal sites are under intensive investigation. Here we report a metabolizable binary supracluster (BSCgal) that combines gold nanoclusters as radiosensitizing adjuvants with small interfering RNA (siRNA) targeting the immunosuppressive mediator galectin-1 (Gal-1). BSCgal comprises reversibly crosslinked cationic gold nanoclusters and siRNA complexes in a polymer matrix that biodegrades over weeks, facilitating clearance (90.3% in vivo clearance at 4 weeks) to reduce toxicity. The particle size well above the renal filtration threshold facilitates passive delivery to tumors. Using mouse models of head and neck cancer, we show that BSCgal augments the radiodynamic and immunotherapeutic effects of SABR at the primary and metastatic tumors by promoting tumor-inhibitory leukocytes, upregulating cytotoxic granzyme B and reducing immunosuppressive cell populations. It outperforms SABR plus Gal-1 antagonists, chemoradiation drug cisplatin or PD-1 inhibitor. This work presents a translatable strategy to converge focal radiosensitization with targeted immune checkpoint silencing for personalized radioimmunotherapy.

Synergistic Potential of Nanomedicine in Prostate Cancer Immunotherapy: Breakthroughs and Prospects

Given the global prevalence of prostate cancer in men, it is crucial to explore more effective treatment strategies. Recently, immunotherapy has emerged as a promising cancer treatment due to its unique mechanism of action and potential long-term effectiveness. However, its limited efficacy in prostate cancer has prompted renewed interest in developing strategies to improve immunotherapy outcomes. Nanomedicine offers a novel perspective on cancer treatment with its unique size effects and surface properties. By employing targeted delivery, controlled release, and enhanced immunogenicity, nanoparticles can be synergized with nanomedicine platforms to amplify the effectiveness of immunotherapy in treating prostate cancer. Simultaneously, nanotechnology can address the limitations of immunotherapy and the challenges of immune escape and tumor microenvironment regulation. Additionally, the synergistic effects of combining nanomedicine with other therapies offer promising clinical outcomes. Innovative applications of nanomedicine include smart nanocarriers, stimulus-responsive systems, and precision medicine approaches to overcome translational obstacles in prostate cancer immunotherapy. This review highlights the transformative potential of nanomedicine in enhancing prostate cancer immunotherapy and emphasizes the need for interdisciplinary collaboration to drive research and clinical applications forward.

Single-Crystal Structural Analysis of 2D Metal-Organic Frameworks and Covalent Organic Frameworks by Three-Dimensional Electron Diffraction

ConspectusIn the development of 2D metal-organic frameworks (MOFs) and 2D covalent organic frameworks (COFs), obtaining structural details at the atomic level is crucial to understanding their properties and related mechanisms in potential applications. However, since 2D-MOFs and COFs are composed of layered structures and often exhibit sheet-like morphologies, it is challenging to grow large crystals suitable for single-crystal X-ray diffraction (SCXRD). Therefore, ab initio structure determination, which refers to solving the structure directly from experimental data without using any prior knowledge or computational input, is extremely rare for 2D-MOFs and COFs. In contrast to SCXRD, three-dimensional electron diffraction (3DED) only requires crystals sized in tens or hundreds of nanometers, making it an ideal method for single-crystal analysis of 2D-MOFs and COFs and obtaining their fine structural details.In this Account, we describe our recent development of the 3DED method and its application in structure determination and property studies of 2D-MOFs and COFs. A key development is the establishment of a continuous 3DED data collection protocol. By collecting electron diffraction (ED) patterns continuously while performing crystal tilting, the electron dose applied to the target nanocrystal is greatly reduced. This allows the acquisition of high-resolution 3DED data from 2D-MOFs and COFs by minimizing their damage under the electron beam. We have also developed an approach to couple 3DED with real-space structure solution methods, i.e., simulated annealing (SA), for single-crystal structural analysis of materials that do not have high crystallinity. We successfully determined two 2D-COF structures by combining 3DED with SA.We provide several examples demonstrating the application of 3DED for the ab initio structure determination of 2D-MOFs and COFs, revealing not only their in-plane structures but also their stacking modes at the atomic level. Notably, the obtained structural details serve as the foundation for further understanding the properties of 2D-MOFs and COFs, such as their electronic band structures, charge mobilities, etc. Beyond structure determination, we describe our work on using 3DED as a high-throughput method for the discovery of new materials. Using this approach, we discovered a novel MOF that was present only in trace amounts within a multiphasic mixture. Through this discovery, we were able to tune the synthesis conditions to obtain its pure phase.We detail how 3DED can be used to probe different levels of molecular motions in MOFs through the analysis of anisotropic displacement parameters (ADPs). Additionally, we show that 3DED can provide accurate information about intermolecular weak interactions such as hydrogen bonding and van der Waals (vdW) interactions. Our studies demonstrate that 3DED is a valuable method for the structural analysis of 2D-MOFs and COFs. We envision that 3DED can accelerate research in these fields by providing unambiguous structural models at the atomic level.

Wrinkled metal-organic framework thin films with tunable Turing patterns for pliable integration

Flexible integration spurs diverse applications in metal-organic frameworks (MOFs). However, current configurations suffer from the trade-off between MOF loadings and mechanical compliance. We report a wrinkled configuration of MOF thin films. We established an interfacial synthesis confined and controlled by a polymer topcoat and achieved multiple Turing motifs in the wrinkled thin films. These films have complete MOF surface coverage and exhibit strain tolerance up to 53.2%. The enhanced mechanical properties allow film transfer onto various substrates. We obtained membranes with large H2/CO2 selectivity (41.2) and high H2 permeance (8.46 × 103 gas permeation units), showcasing negligible defects after transfer. We also achieved soft humidity sensors on delicate electrodes by avoiding exposure to harsh MOF synthesis conditions. These results highlight the potential of wrinkled MOF thin films for plug-and-play integration.

Nanoscaled metal-organic frameworks: charting a transformative path for cancer therapeutics and beyond

Through this inspirational note, we would like to highlight the potential of nanoscaled metal-organic frameworks within the biomedical field. The unique properties of these materials that make them promising candidates for new nanomedicines are assessed here as well as the progression reached so far for combinational cancer therapies and theranostic, along with its most recent advances in nanomedicine. Finally, the perspective and challenges of these materials within this field is discussed.

Nano-Assisted Radiotherapy Strategies: New Opportunities for Treatment of Non-Small Cell Lung Cancer

Lung cancer is the second most commonly diagnosed cancer and a leading cause of cancer-related death, with non-small cell lung cancer (NSCLC) being the most prevalent type. Over 70% of lung cancer patients require radiotherapy (RT), which operates through direct and indirect mechanisms to treat cancer. However, RT can damage healthy tissues and encounter radiological resistance, making it crucial to enhance its precision to optimize treatment outcomes, minimize side effects, and overcome radioresistance. Integrating nanotechnology into RT presents a promising method to increase its efficacy. This review explores various nano-assisted RT strategies aimed at achieving precision treatment. These include using nanomaterials as radiosensitizers, applying nanotechnology to modify the tumor microenvironment, and employing nano-based radioprotectors and radiation-treated cell products for indirect cancer RT. We also explore recent advancements in nano-assisted RT for NSCLC, such as biomimetic targeting that alters mesenchymal stromal cells, magnetic targeting strategies, and nanosensitization with high-atomic number nanomaterials. Finally, we address the existing challenges and future directions of precision RT using nanotechnology, highlighting its potential clinical applications.

Recent Advances in Photosensitizer Materials for Light-Mediated Tumor Therapy

Photodynamic therapy (PDT) as an emerging therapeutic method has drawn much attention in the treatment field for cancer. Photosensitizer, which can convert photon energy into cytotoxic species under light irradiation, is the core component in PDT. The design of photosensitizers still faces problems of light absorption, targeting, penetration and oxygen dependence. With the rapid progress of material science, various photosensitizers have been developed to produce cytotoxic species for treatment of tumor with high selectivity, safety, and noninvasiveness. Besides, the applications of photosensitizers have been expanded to diverse cancer treatments such as drug release, optogenetics and immune checkpoint blockade. In this review, we summarize the recent advances of photosensitizers in various therapeutic methods for cancer. Prevailing challenges and further prospects associated with photosensitizers are also discussed.

Immune checkpoint inhibitors: breakthroughs in cancer treatment

Over the past two decades, immunotherapies have increasingly been considered as first-line treatments for most cancers. One such treatment is immune checkpoint blockade (ICB), which has demonstrated promising results against various solid tumors in clinical trials. Monoclonal antibodies (mAbs) are currently available as immune checkpoint inhibitors (ICIs). These ICIs target specific immune checkpoints, including cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and programmed cell death protein 1 (PD-1). Clinical trial results strongly support the feasibility of this immunotherapeutic approach. However, a substantial proportion of patients with cancer develop resistance or tolerance to treatment, owing to tumor immune evasion mechanisms that counteract the host immune response. Consequently, substantial research focus has been aimed at identifying additional ICIs or synergistic inhibitory receptors to enhance the effectiveness of anti-PD-1, anti-programmed cell death ligand 1 (anti-PD-L1), and anti-CTLA-4 treatments. Recently, several immune checkpoint molecular targets have been identified, such as T cell immunoreceptor with Ig and ITIM domains (TIGIT), mucin domain containing-3 (TIM-3), lymphocyte activation gene-3 (LAG-3), V-domain immunoglobulin suppressor of T cell activation (VISTA), B and T lymphocyte attenuator (BTLA), and signal-regulatory protein α (SIRPα). Functional mAbs targeting these molecules are under development. CTLA-4, PD-1/PD-L1, and other recently discovered immune checkpoint proteins with distinct structures are at the forefront of research. This review discusses these structures, as well as clinical progress in mAbs targeting these immune checkpoint molecules and their potential applications.

Activating CD8+ T Cells by Pt(IV) Prodrug-Based Nanomedicine and aPD-L1 Antibody for Enhanced Cancer Immunotherapy

Recent years have witnessed substantial progress in cancer immunotherapy, specifically T cell-based therapies. However, the application of T cell therapies has been primarily limited to hematologic malignancies, with limited success in the treatment of solid tumors. The main challenge in treating solid tumor is immune escape, which is characterized by reduced antigenicity, diminished immunogenicity, and the development of suppressive tumor immune microenvironments. To address these obstacles and restore T cell-mediated anti-tumor responses, a novel nanoparticle formulation known as PRA@Oxa-c16 is developed. This innovative approach combines retinoic acid and Pt(IV) to specifically target and overcome immune escape. Notably, the therapeutic efficacy of PRA@Oxa-c16 primarily relies on its ability to induce anti-tumor T cell responses, in contrast to the cytotoxicity associated with conventional chemotherapeutic agents. When combined with an immune checkpoint blockade, anti-programmed death-ligand 1 antibody, PRA@Oxa-c16 effectively eliminates solid tumors and induces immune memory responses, which prevent tumor metastasis and recurrence. This promising approach holds great potential for enhancing the treatment of solid tumors with T cell-based immunotherapy.

Spatiotemporal Controllable Sono-Nanovaccines Driven by Free-Field Based Whole-Body Ultrasound for Personalized Cancer Therapy

Therapeutic cancer vaccines fail to produce satisfactory outcomes against solid tumors since vaccine-induced anti-tumor immunity is significantly hampered by immunosuppression. Generating an in situ cancer vaccine targeting immunological cold tumor microenvironment (TME) appears attractive. Here, a type of free-field based whole-body ultrasound (US)-driven nanovaccines are constructed, named G5-CHC-R, by conjugating the sonosensitizer, Chenghai chlorin (CHC) and the immunomodulator, resiquimod (R848) on top of a super small-sized dendrimeric nanoscaffold. Once entering tumors, R848 can be cleaved from a hypoxia-sensitive linker, thus modifying the TME via converting macrophage phenotypes. The animals bearing orthotopic pancreatic cancer with intestinal metastasis and breast cancer with lung metastasis are treated with G5-CHC-R under a free-field based whole-body US system. Benefit from the deep penetration capacity and highly spatiotemporal selectiveness, G5-CHC-R triggered by US represented a superior alternative for noninvasive irradiation of deep-seated tumors and magnification of local immune responses via driving mass release of tumor antigens and "cold-warm-hot" three-state transformation of TME. In addition to irradiating primary tumors, a robust adaptive anti-tumor immunity is potentiated, leading to successful induction of systemic tumor suppression. The sono-nanovaccines with good biocompatibility posed wide applicability to a broad spectrum of tumors, revealing immeasurable potential for translational research in oncology.

MOF@COF Nanocapsules Enhance Soft Tissue Sarcoma Treatment: Synergistic Effects of Photodynamic Therapy and PARP Inhibition on Tumor Growth Suppression and Immune Response Activation

Soft tissue sarcomas (STS) are highly malignant tumors with limited treatment options owing to their heterogeneity and resistance to conventional therapies. Photodynamic therapy (PDT) and poly-ADP-ribose polymerase (PARP) inhibitors (PARPi) have shown potential for STS treatment, with PDT being effective for sarcomas located on the extremities and body surface and PARPi targeting defects in homologous recombination repair. To address the limitations of PDT and harness the potential of PARPi, herein, a novel therapeutic approach for STS treatment combining nanocapsules bearing integrated metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), i.e., MOF@COF, with PDT and PARPi is proposed. Nanocapsules are designed, referred to as ZTN@COF@poloxamer, which contain a Zr-based MOF and tetrakis (4-carbethoxyphenyl) porphyrin as a photosensitizer, are coated with a COF to improve the sensitizing properties, and are loaded with niraparib to inhibit DNA repair. Experiments demonstrate that this new nanocapsules treatment significantly inhibits STS growth, promotes tumor cell apoptosis, exhibits high antitumor activity with minimal side effects, activates the immune response of the tumor, and inhibits lung metastasis in vivo. Therefore, MOF@COF nanocapsules combined with PARPi offer a promising approach for STS treatment, with the potential to enhance the efficacy of PDT and prevent tumor recurrence.

Versatile chondroitin sulfate-based nanoplatform for chemo-photodynamic therapy against triple-negative breast cancer

Versatile nanoplatform equipped with chemo-photodynamic therapeutic attributes play an important role in improving the effectiveness of tumor treatments. Herein, we developed multifunctional nanoparticles based on chondroitin sulfate A (CSA) for the targeted delivery of chlorin e6 (Ce6) and doxorubicin (DOX), in a combined chemo-photodynamic therapy against triple-negative breast cancer. CSA was chosen for its hydrophilic properties and its affinity to CD44 receptor-overexpressed tumor cells. The CSA-ss-Ce6 (CSSC) conjugate was synthesized utilizing a disulfide linker. Subsequently, DOX-loaded CSSC (CSSC-D) nanoparticles were fabricated, showcasing a nearly spherical shape with an average particle size of 267 nm. In the CSSC-D nanoparticles, the chemically attached Ce6 constituted 1.53 %, while the physically encapsulated DOX accounted for 8.11 %. Both CSSC-D and CSSC nanoparticles demonstrated a reduction-sensitive release of DOX or Ce6 in vitro. Under near-infrared (NIR) laser irradiation, CSSC-D showed the enhanced generation of reactive oxygen species (ROS), improving cytotoxic effects against triple-negative breast cancer 4T1 and MDA-MB-231 cells. Remarkably, the CSSC-D with NIR exhibited the most potent tumor growth inhibition in comparison to other groups in the 4T1-bearing Balb/c mice model. Overall, this CSSC-D nanoplatform shows significant promise as a powerful tool for a synergetic approach in chemo-photodynamic therapy in triple-negative breast cancer.

Carbon-Iodine Polydiacetylene Nanofibers for Image-Guided Radiotherapy and Tumor-Microenvironment-Enhanced Radiosensitization

Radiotherapy is a mainstay treatment used in clinics for locoregional therapy, although it still represents a great challenge to improve the sensitivity and accuracy of radiotherapy for tumors. Here, we report the conjugated polymer, polydiiododiacetylene (PIDA), with an iodine content of 84 wt %, as a highly effective computed tomography (CT) contrast agent and tumor microenvironment-responsive radiosensitizer. PIDA exhibited several key properties that contribute to the improvement of precision radiotherapy. The integrated PIDA nanofibers confined within the tumor envelope demonstrated amplified CT intensity and prolonged retention, providing an accurate calculation of dose distribution and precise radiation delivery for CT image-guided radiotherapy. Therefore, our strategy pioneers PIDA nanofibers as a bridge to cleverly connect a fiducial marker to guide accurate radiotherapy and a radiosensitizer to improve tumor sensitivity, thereby minimizing potential damage to surrounding tissues and facilitating on-demand therapeutic intervention in tumors.

Nanomaterials-Involved Tumor-Associated Macrophages' Reprogramming for Antitumor Therapy

Tumor-associated macrophages (TAMs) play pivotal roles in tumor development. As primary contents of tumor environment (TME), TAMs secrete inflammation-related substances to regulate tumoral occurrence and development. There are two kinds of TAMs: the tumoricidal M1-like TAMs and protumoral M2-like TAMs. Reprogramming TAMs from immunosuppressive M2 to immunocompetent M1 phenotype is considered a feasible way to improve immunotherapeutic efficiency. Notably, nanomaterials show great potential for biomedical fields due to their controllable structures and properties. There are many types of nanomaterials that exhibit great regulatory activities for TAMs' reprogramming. In this review, the recent progress of nanomaterials-involved TAMs' reprogramming is comprehensively discussed. The various nanomaterials for TAMs' reprogramming and the reprogramming strategies are summarized and introduced. Additionally, the challenges and perspectives of TAMs' reprogramming for efficient therapy are discussed, aiming to provide inspiration for TAMs' regulator design and promote the development of TAMs-mediated immunotherapy.

Metal-polyphenol "prison" attenuated bacterial outer membrane vesicle for chemodynamics promoted in situ tumor vaccines

As natural adjuvants, the bacterial outer membrane vesicles (OMV) hold great potential in cancer vaccines. However, the inherent immunotoxicity of OMV and the rarity of tumor-specific antigens seriously hamper the clinical translation of OMV-based cancer vaccines. Herein, metal-phenolic networks (MPNs) are used to attenuate the toxicity of OMV, meanwhile, provide tumor antigens via the chemodynamic effect induced immunogenic cell death (ICD). Specifically, MPNs are assembled on the OMV surface through the coordination reaction between ferric ions and tannic acid. The iron-based "prison" is locally collapsed in the tumor microenvironment (TME) with both low pH and high ATP features, and thus the systemic toxicity of OMV is significantly attenuated. The released ferric ions in TME promote the ICD of cancer cells through Fenton reaction and then the generation of abundant tumor antigens, which can be used to fabricate in-situ vaccines by converging with OMV. Together with the immunomodulatory effect of OMV, potent tumor repression on a bilateral tumor model is achieved with good biosafety.

Immunogenic PANoptosis-Initiated Cancer Sono-Immune Reediting Nanotherapy by Iteratively Boosting Cancer Immunity Cycle

The cancer-immune cycle conceptualized the mechanisms of driving T cell responses to tumors, but w as limited by immunological ignorance elicited by tumor inherent immunoediting, which failed to initiate and maintain adaptive immunity. Targeting specific vulnerabilities of cell death patterns may provide unique opportunities to boost T cell antitumor immunological effects. Here an ultrasound nanomedicine-triggered tumor immuno-reediting therapeutic strategy using nano/genetically engineered extracellular vesicles, which can induce tumor highly immunogenic PANoptosis and iteratively start-up the energization of cancer innate immunity cycle by repeatedly liberating damage-associated molecular patterns, thereby priming sufficient antigen-specific T cells and shaping protective immune response through activating cGAS-STING signaling pathways, is reported. Aided by immune checkpoint blockade, the reprogramming of immune microenvironment further facilitated a prompt bridging of innate and adaptive immunity, and remarkably suppressed metastatic and rechallenged tumor growth. Thus, targeting PANoptotic cell death provides a catcher against immune escape and a positive-feedback immune activation gateway for overcoming immune resistance to intractable cancers.

Hafnium (Hf)-Chelating Porphyrin-Decorated Gold Nanosensitizers for Enhanced Radio-Radiodynamic Therapy of Colon Carcinoma

X-ray-induced radiodynamic therapy (RDT) that can significantly reduce radiation dose with an improved anticancer effect has emerged as an attractive and promising therapeutic modality for tumors. However, it is highly significant to develop safe and efficient radiosensitizing agents for tumor radiation therapy. Herein, we present a smart nanotheranostic system FA-Au-CH that consists of gold nanoradiosensitizers, photosensitizer chlorin e6 (Ce6), and folic acid (FA) as a folate-receptor-targeting ligand for improved tumor specificity. FA-Au-CH nanoparticles have been demonstrated to be able to simultaneously serve as radiosensitizers and RDT agents for enhanced computed tomography (CT) imaging-guided radiotherapy (RT) of colon carcinoma, owing to the strong X-ray attenuation capability of high-Z elements Au and Hf, as well as the characteristics of Hf that can transfer radiation energy to Ce6 to generate ROS from Ce6 under X-ray irradiation. The integration of RT and RDT in this study demonstrates great efficacy and offers a promising therapeutic modality for the treatment of malignant tumors.

Nanointegrative In Situ Reprogramming of Tumor-Intrinsic Lipid Droplet Biogenesis for Low-Dose Radiation-Activated Ferroptosis Immunotherapy

Low-dose radiotherapy (LDR) has shown significant implications for inflaming the immunosuppressive tumor microenvironment (TME). Surprisingly, we identify that FABP-dependent lipid droplet biogenesis in tumor cells is a key determinant of LDR-evoked cytotoxic and immunostimulatory effects and developed a nanointegrated strategy to promote the antitumor efficacy of LDR through cooperative ferroptosis immunotherapy. Specifically, TCPP-TK-PEG-PAMAM-FA, a nanoscale multicomponent functional polymer with self-assembly capability, was synthesized for cooperatively entrapping hafnium ions (Hf4+) and HIF-1α-inhibiting siRNAs (siHIF-1α). The TCPP@Hf-TK-PEG-PAMAM-FA@siHIF-1α nanoassemblies are specifically taken in by folate receptor-overexpressing tumor cells and activated by the elevated cellular ROS stress. siHIF-1α could readily inhibit the FABP3/7 expression in tumor cells via HIF-1α-FABP3/7 signaling and abolish lipid droplet biogenesis for enhancing the peroxidation susceptibility of membrane lipids, which synergizes with the elevated ROS stress in the context of Hf4+-enhanced radiation exposure and evokes pronounced ferroptotic damage in vital membrane structures. Interestingly, TCPP@Hf-TK-PEG-PAMAM-FA@siHIF-1α-enhanced ferroptotic biomembrane damage also facilitates the exposure of tumor-associated antigens (TAAs) to promote post-LDR immunotherapeutic effects, leading to robust tumor regression in vivo. This study offers a nanointegrative approach to boost the antitumor effects of LDR through the utilization of tumor-intrinsic lipid metabolism.

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.

Stimuli-Responsive Nanoadjuvant Rejuvenates Robust Immune Responses to Sensitize Cancer Immunotherapy

Despite their immense therapeutic potential, cancer immunotherapies such as immune checkpoint blockers (ICBs) benefit only a small subset of patients. Toll-like receptor agonists reverse the immunosuppressive tumor microenvironment (TME) to enhance antitumor immunity, but their systemic administration induces side effects. This work describes a TME-responsive nanotherapeutic platform for the site-specific release of drug candidates in tumors with a significant antitumor efficacy. Imidazoquinoline (IMQ)-derived liposomal nanovesicles (LN-IMQ) triggered the antitumor ability of macrophages, mobilized T-cell immunity, and promoted the secretion of antitumor cytokines, explaining the synergistic effect of LN-IMQ with ICBs. LN-IMQ monotherapy observed complete tumor regression in 6/8 of 4T1-bearing mouse, and cured mice resisted secondary tumor challenge. Besides, LN-IMQ decreased the occurrence of lung metastases, being effective against advanced metastases. On the other hand, neoantigen-based cancer vaccine has very low immune responses. Here, we also verified that LN-IMQ can serve as an ideal tumor antigen delivery vector. Cancer cells in vitro treated with chemotherapeutic drugs included multiple neoantigens and high levels of damage-associated molecular patterns, which were then successfully encapsulated in LN-IMQ to obtain a "personalized nanovaccine" with artificially amplified antigenicity and adjuvant properties. This study developed an attractive potential personalized nanovaccine for chemotherapeutic-drug-induced tumor neoantigens and immunotherapy.

Reactive oxygen nanobiocatalysts: activity-mechanism disclosures, catalytic center evolutions, and changing states

Benefiting from low costs, structural diversities, tunable catalytic activities, feasible modifications, and high stability compared to the natural enzymes, reactive oxygen nanobiocatalysts (RONBCs) have become dominant materials in catalyzing and mediating reactive oxygen species (ROS) for diverse biomedical and biological applications. Decoding the catalytic mechanism and structure-reactivity relationship of RONBCs is critical to guide their future developments. Here, this timely review comprehensively summarizes the recent breakthroughs and future trends in creating and decoding RONBCs. First, the fundamental classification, activity, detection method, and reaction mechanism for biocatalytic ROS generation and elimination have been systematically disclosed. Then, the merits, modulation strategies, structure evolutions, and state-of-art characterisation techniques for designing RONBCs have been briefly outlined. Thereafter, we thoroughly discuss different RONBCs based on the reported major material species, including metal compounds, carbon nanostructures, and organic networks. In particular, we offer particular insights into the coordination microenvironments, bond interactions, reaction pathways, and performance comparisons to disclose the structure-reactivity relationships and mechanisms. In the end, the future challenge and perspectives for RONBCs are also carefully summarised. We envision that this review will provide a comprehensive understanding and guidance for designing ROS-catalytic materials and stimulate the wide utilisation of RONBCs in diverse biomedical and biological applications.

A Universal Cyclodextrin-Based Nanovaccine Platform Delivers Epitope Peptides for Enhanced Antitumor Immunity

Currently, there is still an intense demand for a simple and scalable delivery platform for peptide-based cancer vaccines. Herein, a cyclodextrin-based polymer nanovaccine platform (CDNP) is designed for the codelivery of peptides with two immune adjuvants [the Toll-like receptor (TLR)7/8 agonist R848 and the TLR9 agonist CpG] that is broadly applicable to epitope peptides with diverse sequences. Specifically, the cyclodextrin-based polymers are covalently linked to epitope peptides via a bioreactive bond-containing cross-linker (PNC-DTDE-PNC) and then physically load with R848 and CpG to obtain CDNP. The CDNP efficiently accumulats in the lymph nodes (LNs), greatly facilitating antigen capture and cross-presentation by antigen-presenting cells. The immunogenicity of the epitope peptides is significantly enhanced by the codelivery and synergy of the adjuvants, and the CDNP shows the ability to inhibit tumor progression in diverse tumor-bearing mouse models. It is concluded that CDNP holds promise as an optimized peptide-based cancer vaccine platform.

Fe(III)-Shikonin supramolecular nanomedicines as immunogenic cell death stimulants and multifunctional immunoadjuvants for tumor vaccination

Immunoadjuvants, as an indispensable component of tumor vaccines, can observably enhance the magnitude, breadth, and durability of antitumor immunity. However, current immunoadjuvants suffer from different issues such as weak immunogenicity, inadequate cellular internalization, poor circulation time, and mono-functional bioactivity. Methods: Herein, we construct Fe3+-Shikonin metal-phenolic networks (FeShik) nanomedicines as immunogenic cell death (ICD) stimulants and multifunctional immunoadjuvants for tumor vaccination. The multifunctionality of FeShik nanomedicines is investigated by loading ovalbumin (OVA) as the model antigen to construct OVA@FeShik nanovaccines or 4T1 tumor cell fragment (TF) as homologous antigen to construct TF@FeShik nanovaccines. In vitro examinations including GSH responsive, •OH generation, colloid stability, cellular uptake, cytotoxicity mechanism of ferroptosis and necroptosis, ICD effect, the promotion of DC maturation and antigen cross-presentation were studied. In vivo observations including pharmacokinetics and biodistribution, antitumor effect, abscopal effect, immune memory effect, and biosafety were performed. Results: The presence of FeShik nanomedicines can significantly prolong the blood circulation time of antigens, increasing the bioavailability of antigens. Upon phagocytosis by tumor cells, FeShik nanomedicines can disassemble into Fe2+ and Shikonin in response to tumor microenvironments, leading to ICD of tumor cells via ferroptosis and necroptosis. Consequently, ICD-released autologous tumor cell lysates and pro-inflammatory cytokines not only stimulate DC maturation and antigen cross-presentation, but also promote macrophage repolarization and cytotoxic T lymphocyte infiltration, resulting in the activation of adaptive immune responses toward solid tumors. Conclusion: In a word, our FeShik supramolecular nanomedicines integrate bioactivities of ICD stimulants and immunoadjuvants, such as eradicating tumor cells, activating antitumor immune responses, modulating immunosuppressive tumor microenvironments, and biodegradation after immunotherapy. Encouraged by the diversity of polyphenols and metal ions, our research may provide a valuable paradigm to establish a large library for tumor vaccination.

Zinc-Organometallic Framework Vaccine Controlled-Release Zn2+ Regulates Tumor Extracellular Matrix Degradation Potentiate Efficacy of Immunotherapy

Tumor extracellular matrix (ECM) not only forms a physical barrier for T cells infiltration, but also regulates multiple immunosuppressive pathways, which is an important reason for immunotherapy failure. The cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon genes (cGAS-STING) pathway plays a key role in activating CD8+ T cells, maintaining CD8+ T cells stemness and enhancing the antitumor effect. Herein, a zinc-organometallic framework vaccine (ZPM@OVA-CpG) prepared by self-assembly, which achieves site-directed release of Zn2+ in dendritic cell (DC) lysosomes and tumor microenvironment under acidic conditions, is reported. The vaccine actively targets DC, significantly enhances cGAS-STING signal, promotes DC maturation and antigen cross-presentation, and induces strong activation of CD8+ T cells. Meanwhile, the vaccine reaches the tumor site, releasing Zn2+ , significantly up-regulates the activity of matrix metalloproteinase-2, degrades various collagen components of tumor ECM, effectively alleviates immune suppression, and significantly enhances the tumor infiltration and killing of CD8+ T cells. ZPM@OVA-CpG vaccine not only solves the problem of low antigen delivery efficiency and weak CD8+ T cells activation ability, but also achieves the degradation of tumor ECM via the vaccine for the first time, providing a promising therapeutic platform for the development of efficient novel tumor vaccines.

Manganese-Based Immunostimulatory Metal-Organic Framework Activates the cGAS-STING Pathway for Cancer Metalloimmunotherapy

Metal-organic frameworks (MOFs) show tremendous promise for drug delivery due to their structural and functional versatility. However, MOFs are usually used as biologically inert carriers in most cases. The creation of intrinsically immunostimulatory MOFs remains challenging. In this study, a facile and green synthesis method is proposed for the preparation of a manganese ion (Mn2+)-based immunostimulatory MOF (ISAMn-MOF) for cancer metalloimmunotherapy. ISAMn-MOF significantly facilitates the activation of cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) related genes and signaling pathways in bone-marrow-derived dendritic cells (BMDCs). BMDCs treated with ISAMn-MOF secrete 4-fold higher type I interferon and 2- to 16-fold higher proinflammatory cytokines than those treated with equivalent MnCl2. ISAMn-MOF alone or its combination with immune checkpoint antibodies significantly suppresses tumor growth and metastasis and prolongs mouse survival. Mechanistic studies indicate that ISAMn-MOF treatment facilitates the infiltration of stimulatory immune cells in tumors and lymphoid organs. This study provides insight into the design of bioactive MOFs for improved cancer metalloimmunotherapy.

The extracellular matrix - immune microenvironment crosstalk in cancer therapy: Challenges and opportunities

Targeting the tumour immune microenvironment (TIME) by cancer immunotherapy has led to improved patient outcomes. However, response to these treatments is heterogeneous and cancer-type dependant. The therapeutic activity of classical cancer therapies such as chemotherapy, radiotherapy, and surgical oncology is modulated by alterations of the TIME. A major regulator of immune cell function and resistance to both immune and classical therapies is the extracellular matrix (ECM). Concurrently, cancer therapies reshape the TIME as well as the ECM, causing both pro- and anti-tumour responses. Accordingly, the TIME-ECM crosstalk presents attractive opportunities to improve therapy outcomes. Here, we review the molecular crosstalk between the TIME and the ECM in cancer and its implications in cancer progression and clinical intervention. Additionally, we discuss examples and future directions of ECM and TIME co-targeting in combination with oncological therapies including surgery, chemotherapy, and radiotherapy.

Targeting and arginine-driven synergizing photodynamic therapy with nutritional immunotherapy nanosystems for combating MRSA biofilms

The resistance and immune escape of methicillin-resistant Staphylococcus aureus (MRSA) biofilms cause recalcitrant infections. Here, we design a targeting and synergizing cascade PDT with nutritional immunotherapy nanosystems (Arg-PCN@Gel) containing PCN-224 as PDT platform for providing reactive oxygen species (ROS), incorporating arginine (Arg) as nitric oxide (NO) donor to cascade with ROS to produce more lethal ONOO- and promote immune response, and coating with gelatin as targeting agent and persistent Arg provider. The nanosystems adhered to the autolysin of MRSA and inhibited Arg metabolism by down-regulating icdA and icaA. It suppressed polysaccharide intercellular adhesin and extracellular DNA synthesis to prevent biofilm formation. The NO broke mature biofilms and helped ROS and ONOO- penetrate into biofilms to inactivate internal MRSA. Arg-PCN@Gel drove Arg to enhance immunity via inducible NO synthase/NO axis and arginase/polyamine axis and achieve efficient target treatment in MRSA biofilm infections. The targeting and cascading PDT synergized with nutritional immunotherapy provide an effective promising strategy for biofilm-associated infections.

Radiation combined with immune checkpoint inhibitors for unresectable locally advanced non-small cell lung cancer: synergistic mechanisms, current state, challenges, and orientations

Until the advent of immune checkpoint inhibitors (ICIs), definitive radiotherapy (RT) concurrently with chemotherapy was recommended for unresectable, locally advanced non-small cell lung cancer (LA-NSCLC). The trimodality paradigm with consolidation ICIs following definitive concurrent chemoradiotherapy has been the standard of care since the PACIFIC trial. Preclinical evidence has demonstrated the role of RT in the cancer-immune cycle and the synergistic effect of RT combined with ICIs (iRT). However, RT exerts a double-edged effect on immunity and the combination strategy still could be optimized in many areas. In the context of LA-NSCLC, optimized RT modality, choice, timing, and duration of ICIs, care for oncogenic addicted tumors, patient selection, and novel combination strategies require further investigation. Targeting these blind spots, novel approaches are being investigated to cross the borders of PACIFIC. We discussed the development history of iRT and summarized the updated rationale for the synergistic effect. We then summarized the available research data on the efficacy and toxicity of iRT in LA-NSCLC for cross-trial comparisons to eliminate barriers. Progression during and after ICIs consolidation therapy has been regarded as a distinct resistance scenario from primary or secondary resistance to ICIs, the subsequent management of which has also been discussed. Finally, based on unmet needs, we probed into the challenges, strategies, and auspicious orientations to optimize iRT in LA-NSCLC. In this review, we focus on the underlying mechanisms and recent advances of iRT with an emphasis on future challenges and directions that warrant further investigation. Taken together, iRT is a proven and potential strategy in LA-NSCLC, with multiple promising approaches to further improve the efficacy. Video Abstract.

Radiation-induced tumor immune microenvironments and potential targets for combination therapy

As one of the four major means of cancer treatment including surgery, radiotherapy (RT), chemotherapy, immunotherapy, RT can be applied to various cancers as both a radical cancer treatment and an adjuvant treatment before or after surgery. Although RT is an important modality for cancer treatment, the consequential changes caused by RT in the tumor microenvironment (TME) have not yet been fully elucidated. RT-induced damage to cancer cells leads to different outcomes, such as survival, senescence, or death. During RT, alterations in signaling pathways result in changes in the local immune microenvironment. However, some immune cells are immunosuppressive or transform into immunosuppressive phenotypes under specific conditions, leading to the development of radioresistance. Patients who are radioresistant respond poorly to RT and may experience cancer progression. Given that the emergence of radioresistance is inevitable, new radiosensitization treatments are urgently needed. In this review, we discuss the changes in irradiated cancer cells and immune cells in the TME under different RT regimens and describe existing and potential molecules that could be targeted to improve the therapeutic effects of RT. Overall, this review highlights the possibilities of synergistic therapy by building on existing research.

Nanoparticle-Mediated Radiotherapy Remodels the Tumor Microenvironment to Enhance Antitumor Efficacy

Radiotherapy (RT) uses ionizing radiation to eradicate localized tumors and, in rare cases, control tumors outside of the irradiated fields via stimulating an antitumor immune response (abscopal effect). However, the therapeutic effect of RT is often limited by inherent physiological barriers of the tumor microenvironment (TME), such as hypoxia, abnormal vasculature, dense extracellular matrix (ECM), and an immunosuppressive TME. Thus, it is critical to develop new RT strategies that can remodel the TME to overcome radio-resistance and immune suppression. In the past decade, high-Z-element nanoparticles have been developed to increase radiotherapeutic indices of localized tumors by reducing X-ray doses and side effects to normal tissues and enhance abscopal effects by activating the TME to elicit systemic antitumor immunity. In this review, the principles of RT and radiosensitization, the mechanisms of radio-resistance and immune suppression, and the use of various nanoparticles to sensitize RT and remodel TMEs for enhanced antitumor efficacy are discussed. The challenges in clinical translation of multifunctional TME-remodeling nanoradiosensitizers are also highlighted.

Recent Advances of Fe(III)/Fe(II)-MPNs in Biomedical Applications

Metal-phenolic networks (MPNs) are a new type of nanomaterial self-assembled by metal ions and polyphenols that have been developed rapidly in recent decades. They have been widely investigated, in the biomedical field, for their environmental friendliness, high quality, good bio-adhesiveness, and bio-compatibility, playing a crucial role in tumor treatment. As the most common subclass of the MPNs family, Fe-based MPNs are most frequently used in chemodynamic therapy (CDT) and phototherapy (PTT), where they are often used as nanocoatings to encapsulate drugs, as well as good Fenton reagents and photosensitizers to improve tumor therapeutic efficiency substantially. In this review, strategies for preparing various types of Fe-based MPNs are first summarized. We highlight the advantages of Fe-based MPNs under the different species of polyphenol ligands for their application in tumor treatments. Finally, some current problems and challenges of Fe-based MPNs, along with a future perspective on biomedical applications, are discussed.

Tantalum-Zirconium Co-Doped Metal-Organic Frameworks Sequentially Sensitize Radio-Radiodynamic-Immunotherapy for Metastatic Osteosarcoma

Due to radiation resistance and the immunosuppressive microenvironment of metastatic osteosarcoma, novel radiosensitizers that can sensitize radiotherapy (RT) and antitumor immunity synchronously urgently needed. Here, the authors developed a nanoscale metal-organic framework (MOF, named TZM) by co-doping high-atomic elements Ta and Zr as metal nodes and porphyrinic molecules (tetrakis(4-carboxyphenyl)porphyrin (TCPP)) as a photosensitizing ligand. Given the 3D arrays of ultra-small heavy metals, porous TZM serves as an efficient attenuator absorbing X-ray energy and sensitizing hydroxyl radical generation for RT. Ta-Zr co-doping narrowed the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) energy gap and exhibited close energy levels between the singlet and triplet photoexcited states, facilitating TZM transfer energy to the photosensitizer TCPP to sensitize singlet oxygen (1 O2 ) generation for radiodynamic therapy (RDT). The sensitized RT-RDT effects of TZM elicit a robust antitumor immune response by inducing immunogenic cell death, promoting dendritic cell maturation, and upregulating programmed cell death protein 1 (PD-L1) expression via the cGAS-STING pathway. Furthermore, a combination of TZM, X-ray, and anti-PD-L1 treatments amplify antitumor immunotherapy and efficiently arrest osteosarcoma growth and metastasis. These results indicate that TZM is a promising radiosensitizer for the synergistic RT and immunotherapy of metastatic osteosarcoma.

Catalytic nanotechnology of X-ray photodynamics for cancer treatments

Photodynamic therapy (PDT) has been applied in cancer treatment because of its high selectivity, low toxicity, and non-invasiveness. However, the limited penetration depth of the light still hampers from reaching deep-seated tumors. Considering the penetrating ability of high-energy radiotherapy, X-ray-induced photodynamic therapy (X-PDT) has evolved as an alternative to overcome tissue blocks. As the basic principle of X-PDT, X-rays stimulate the nanoparticles to emit scintillating or persistent luminescence and further activate the photosensitizers to generate reactive oxygen species (ROS), which would cause a series of molecular and cellular damages, immune response, and eventually break down the tumor tissue. In recent years, catalytic nanosystems with unique structures and functions have emerged that can enhance X-PDT therapeutic effects via an immune response. The anti-cancer effect of X-PDT is closely related to the following factors: energy conversion efficiency of the material, the radiation dose of X-rays, quantum yield of the material, tumor resistance, and biocompatibility. Based on the latest research in this field and the classical theories of nanoscience, this paper systematically elucidates the current development of the X-PDT and related immunotherapy, and highlights its broad prospects in medical applications, discussing the connection between fundamental science and clinical translation.

Bypassing anti-PD-(L)1 therapy: Mechanisms and management strategies

Resistance to immune checkpoint inhibitors (ICIs) is a major issue of the current era in cancer immunotherapy. Immune evasion is a multi-factorial event, which occurs generally at a base of cold immunity. Despite advances in the field, there are still unsolved challenges about how to combat checkpoint hijacked by tumor cells and what are complementary treatment strategies to render durable anti-tumor outcomes. A point is that anti-programed death-1 receptor (PD-1)/anti-programmed death-ligand 1 (PD-L1) is not the solo path of immune escape, and responses in many types of solid tumors to the PD-1/PD-L1 inhibitors are not satisfactory. Thus, seeking mechanisms inter-connecting tumor with its immune ecosystem nearby unravel more about resistance mechanisms so as to develop methods for sustained reinvigoration of immune activity against cancer. In this review, we aimed to discuss about common and specific paths taken by tumor cells to evade immune surveillance, describing novel detection strategies, as well as suggesting some approaches to recover tumor sensitivity to the anti-PD-(L)1 therapy based on the current knowledge.

"Cluster Bomb" Based Bismuth Nano-in-Micro Spheres Formed Dry Powder Inhalation for Thermo-Radio Sensitization Effects of Lung Metastatic Breast Cancer

Lung metastatic breast cancer (LMBC) is mainly diagnosed through CT imaging and radiotherapy could be the most common method in the clinic to inhibit tumor proliferation. While the sensitivity of radiotherapy is always limited due to the hypoxic tumor microenvironment and high doses of irradiation easily induce systemic cytotoxicity. Metal-based materials applied as radiosensitizers have been widely investigated to improve efficiency and reduce the doses of irradiation. Herein, it is aimed to overcome these problems by designing biodegradable lipid-camouflaged bismuth-based nanoflowers (DP-BNFs) as both a photo-thermo-radiosensitizer to develop a novel photothermal therapy (PTT) and radiotherapy combination strategy for LMBC treatment. To achieve effective lung deposition, "Cluster Bomb" structure-based DP-BNFs nano-in-micro dry powder inhalation (DP-BNF@Lat-MPs) are formulated through spray-dried technology. The DP-BNFs "cluster" in the microsphere to improve their tumor-targeted lung deposition with a high fine particle fraction followed by burst releasing of DP-BNFs for targeting delivery and LMBC therapy. The DP-BNF@Lat-MPs exhibit excellent photothermal conversion efficiency, radiotherapy enhancement, and CT imaging ability in vitro, which synergistically inhibit cell proliferation and metastasis. In vitro and in vivo data prove that combining PTT and radiotherapy with DP-BNF@Lat-MPs as a thermo-radio dual-sensitizer significantly enhances LMBC tumor metastasis inhibition with good biocompatibility and low toxicity.

Nanomedicine embraces cancer radio-immunotherapy: mechanism, design, recent advances, and clinical translation

Cancer radio-immunotherapy, integrating external/internal radiation therapy with immuno-oncology treatments, emerges in the current management of cancer. A growing number of pre-clinical studies and clinical trials have recently validated the synergistic antitumor effect of radio-immunotherapy, far beyond the "abscopal effect", but it suffers from a low response rate and toxicity issues. To this end, nanomedicines with an optimized design have been introduced to improve cancer radio-immunotherapy. Specifically, these nanomedicines are elegantly prepared by incorporating tumor antigens, immuno- or radio-regulators, or biomarker-specific imaging agents into the corresponding optimized nanoformulations. Moreover, they contribute to inducing various biological effects, such as generating in situ vaccination, promoting immunogenic cell death, overcoming radiation resistance, reversing immunosuppression, as well as pre-stratifying patients and assessing therapeutic response or therapy-induced toxicity. Overall, this review aims to provide a comprehensive landscape of nanomedicine-assisted radio-immunotherapy. The underlying working principles and the corresponding design strategies for these nanomedicines are elaborated by following the concept of "from bench to clinic". Their state-of-the-art applications, concerns over their clinical translation, along with perspectives are covered.

Emerging Sonodynamic Therapy-Based Nanomedicines for Cancer Immunotherapy

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

Recent Progress and Trends in X-ray-Induced Photodynamic Therapy with Low Radiation Doses

The prominence of photodynamic therapy (PDT) in treating superficial skin cancer inspires innovative solutions for its congenitally deficient shadow penetration of the visible-light excitation. X-ray-induced photodynamic therapy (X-PDT) has been proven to be a successful technique in reforming the conventional PDT for deep-seated tumors by creatively utilizing penetrating X-rays as external excitation sources and has witnessed rapid developments over the past several years. Beyond the proof-of-concept demonstration, recent advances in X-PDT have exhibited a trend of minimizing X-ray radiation doses to quite low values. As such, scintillating materials used to bridge X-rays and photosensitizers play a significant role, as do diverse well-designed irradiation modes and smart strategies for improving the tumor microenvironment. Here in this review, we provide a comprehensive summary of recent achievements in X-PDT and highlight trending efforts using low doses of X-ray radiation. We first describe the concept of X-PDT and its relationships with radiodynamic therapy and radiotherapy and then dissect the mechanism of X-ray absorption and conversion by scintillating materials, reactive oxygen species evaluation for X-PDT, and radiation side effects and clinical concerns on X-ray radiation. Finally, we discuss a detailed overview of recent progress regarding low-dose X-PDT and present perspectives on possible clinical translation. It is expected that the pursuit of low-dose X-PDT will facilitate significant breakthroughs, both fundamentally and clinically, for effective deep-seated cancer treatment in the near future.

Recent Clinical and Preclinical Advances in External Stimuli-Responsive Therapies for Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) has long been one of the most prevalent cancers worldwide; even though treatments such as surgery, chemotherapy, radiotherapy and immunotherapy have been proven to benefit the patients and prolong their survival time, the overall five-year survival rate is still below 50%. Hence, the development of new therapies for better patient management is an urgent need. External stimuli-responsive therapies are emerging therapies with promising antitumor effects; therapies such as photodynamic (PDT) and photothermal therapies (PTT) have been tested clinically in late-stage HNSCC patients and have achieved promising outcomes, while the clinical translation of sonodynamic therapy (SDT), radiodynamic therapy (RDT), microwave dynamic/thermodynamic therapy, and magnetothermal/magnetodynamic therapy (MDT/MTT) still lag behind. In terms of preclinical studies, PDT and PTT are also the most extensively studied therapies. The designing of nanoparticles and combinatorial therapies of PDT and PTT can be referenced in designing other stimuli-responsive therapies in order to achieve better antitumor effects as well as less toxicity. In this review, we consolidate the advancements and limitations of various external stimuli-responsive therapies, as well as critically discuss the prospects of this type of therapies in HNSCC treatments.