High Immunogenic Cuproptosis Evoked by In Situ Sulfidation-Activated Pyroptosis for Tumor-Targeted Immunotherapy of Colorectal Cancer

Cuproptosis: mechanisms and nanotherapeutic strategies in cancer and beyond

Cuproptosis, a novel form of copper (Cu)-dependent programmed cell death, is induced by directly binding Cu species to lipoylated components of the tricarboxylic acid (TCA) cycle. Since its discovery in 2022, cuproptosis has been closely linked to the field of materials science, offering a biological basis and bright prospects for the use of Cu-based nanomaterials in various disease treatments. Owing to the unique physicochemical properties of nanomaterials, Cu delivery nanosystems can specifically increase Cu levels at disease sites, inducing cuproptosis to achieve disease treatment while minimizing the undesirable release of Cu in normal tissues. This innovative nanomaterial-mediated cuproptosis, termed as "nanocuproptosis", positions at the intersection of chemistry, materials science, pharmaceutical science, and clinical medicine. This review aims to comprehensively summarize and discuss recent advancements in cuproptosis across various diseases, with a particular focus on cancer. It delves into the biochemical basis of nanomaterial-mediated cuproptosis, the rational design for cuproptosis inducers, strategies for enhancing therapeutic specificity, and cuproptosis-centric synergistic cancer therapeutics. Beyond oncology, this review also explores the expanded applications of cuproptosis, such as antibacterial, wound healing, and bone tissue engineering, highlighting its great potential to open innovative therapeutic strategies. Furthermore, the clinical potential of cuproptosis is assessed from basic, preclinical to clinical research. Finally, this review addresses current challenges, proposes potential solutions, and discusses the future prospects of this burgeoning field, highlighting cuproptosis nanomedicine as a highly promising alternative to current clinical therapeutics.

Biomimetic Copper Nanozyme Reprograms Cold Tumor via Cuproptosis-Pyroptosis Crosstalk for Potent Renal Carcinoma Immunotherapy

Immune checkpoint blockade (ICB) therapy is an emerging strategy for renal cell carcinoma (RCC). However, its clinical efficacy remains constrained by its inherently poor immunogenicity and insufficient cytotoxic T lymphocyte (CTL) infiltration. Herein, we engineer a biomimetic copper nanozyme (Cu2O-OMV) by integrating Cu2O nanoparticles with bacterial outer-membrane vesicles (OMVs) to activate the antitumor immune response and synergize with ICB therapy. The Cu2O-OMV nanozyme exhibits peroxidase (POD)-like catalytic activity and releases Cu+ to exert Fenton-like activity, generating cytotoxic hydroxyl radicals (·OH) for tumor inhibition. Furthermore, Cu+ accumulation promotes the occurrence of cuproptosis, leading to the mitochondrial aggregation of lipoylated dihydrolipoamide S-acetyltransferase and depletion of ferredoxin 1. Notably, Cu2O-OMV concurrently activates pyroptosis via the noncanonical inflammasome pathway through its intrinsic lipopolysaccharide cargo, directly inhibiting tumor growth and inducing inflammatory cytokine release. The coordinated induction of cuproptosis and pyroptosis synergistically amplifies immunogenic cell death to enhance tumor immunogenicity, thereby promoting dendritic cell maturation and CTL infiltration. After combining with αPD-L1, it effectively destroys tumor cells to activate the antitumor immune response, thereby inhibiting tumor metastasis. Our study demonstrates a biomimetic nanozyme-driven strategy that harnesses dual cuproptosis-pyroptosis pathways to enhance the tumor immunogenicity and amplify the ICB efficacy, offering a transformative approach for RCC immunotherapy.

Microwave-Responsive AlEu-MOFs Potentiate NLRP3-Mediated Pyroptosis via a "Triple Initiating" Tactic for Breast Cancer Microwave-Immunotherapy

Microwave thermotherapy is favored in clinical practice for breast cancer conservation strategies due to its minimally invasive characteristic. Nevertheless, the immunosuppressive tumor microenvironment (TME) significantly attenuates the therapeutic efficacy of anti-tumor immune response, posing challenges in effectively preventing tumor recurrence and metastasis. Pyroptosis, a recently identified form of programmed cell death triggered by inflammasomes, presents unique inflammatory and immunogenic properties that hold promise for cancer immunotherapy. Herein, microwave-responsive AlEu-MOFs are designed and synthesized to boost NLRP3-mediated pyroptosis via a "Triple Initiating" tactic for breast cancer microwave-immunotherapy. The potent microwave thermal effect of AEM facilitates the up-regulation of HSP90, thereby initiating NLRP3 expression. Concurrently, it induces mitochondrial dysfunction to generate substantial quantities of ROS, further enhancing NLRP3 expression to achieve a targeted amplification of microwave thermotherapy-induced pyroptosis. Simultaneously, the microwave-responsive directed anchoring release of highly active metal ions promotes the activation of the NLRP3 inflammasome jointly, ultimately inducing high-efficiency pyroptosis. This innovative "2M" (materials and methods) dual-pronged strategy not only significantly inhibits primary tumor proliferation, but also further impedes distant tumor progression and lung metastasis. This work provides a novel strategy to accurately and effectively achieve pyroptosis and offers a new approach to overcome the obstacles of clinical microwave thermotherapy.

Metal-based immunogenic cell death inducers for cancer immunotherapy

Immunogenic cell death (ICD) has attracted enormous attention over the past decade due to its unique characteristics in cancer cell death and its role in activating innate and adaptive immune responses against tumours. Many efforts have been dedicated to screening, identifying and discovering ICD inducers, resulting in the validation of several based on metal complexes. In this review, we provide a comprehensive summary of current metal-based ICD inducers, their molecular mechanisms for triggering ICD initiation and subsequent protective antitumour immune responses, along with considerations for validating ICD both in vitro and in vivo. We also aim to offer insights into the future development of metal complexes with enhanced ICD-inducing properties and their applications in potentiating antitumour immunity.

Advances in cuproptosis harnessing copper-based nanomaterials for cancer therapy

Cuproptosis, a newly identified programmed cell death form, is characterized by excessive copper accumulation in cells, resulting in mitochondria damage and toxic protein stress, ultimately causing cell death. Given the considerable therapeutic promise of copper toxicity in cancer treatment, copper-based nanomaterials that induce copper death have attracted interest as a promising approach for tumor therapy. This review comprehensively introduces the mechanisms of cuproptosis and the associated regulatory genes, including both positive and negative regulatory regulators, and systematically summarizes the application of various nanoparticles in inducing cuproptosis, ranging from inorganic copper compounds to delivery systems. These nanoparticles offer significant advantages, such as improving copper absorption, extending the duration of effectiveness, enhancing the precision of copper release, increasing biocompatibility, and serving as enhancers in combination therapy. In conclusion, the authors present a detailed overview and insights into the current research directions of nanoplatforms that facilitate copper-induced cancer treatment, establishing a foundation for the future development of effective nanomedicines that induce cuproptosis and offering new possibilities and treatment strategies for tumor therapy.

Targeted therapy with polymeric nanoparticles in PBRM1-mutant biliary tract cancers: Harnessing DNA damage repair mechanisms

Biliary tract cancers (BTCs) are aggressive malignancies with a dismal prognosis that require intensive targeted therapy. Approximately 10 % of BTCs have PBRM1 mutations, which impede DNA damage repair pathways and make cancer cells more susceptible to DNA-damaging chemicals. This review focus on development of poly(lactic-co-glycolic acid) (PLGA)-based nanoparticles targeting delivery system to selectively deliver chemotherapy into PBRM1-deficient BTC cells. These nanoparticles improve therapy efficacy by increasing medication targeting and retention at tumour locations. In preclinical studies, pharmacokinetic profile of this nanoparticle was encouraging and supported its ability to achieve extended circulation time with high drug accumulation in tumor. The review also highlights potential of Pou3F3:I54N to expedite bioassays for patient selection in BTC targeted therapies.

PEGylated Elesclomol@Cu(Ⅱ)-based Metal‒organic framework with effective nanozyme performance and cuproptosis induction efficacy for enhanced PD-L1-based immunotherapy

Nanozymes constitute a promising treatment strategy for antitumor therapy. However, the catalytic function of metal‒organic framework (MOF)-based nanozymes during cuproptosis remains unclear. In this study, a Cu(Ⅱ)-based MOF nanocomposite loaded with the copper ionophore elesclomol and surface modified with polyethylene glycol polymer (PEG) was developed (ES@Cu(Ⅱ)-MOF) for effective cuproptosis induction. The peroxidase (POD)-like activity of ES@Cu(Ⅱ)-MOF generated an abundance of hydroxyl radicals (•OH) via a Fenton-like reaction, and its glutathione peroxidase (GSH-Px)-like activity converted Cu2+ into more toxic Cu+ ions to efficiently consume endogenous GSH. Notably, the rapid accumulation of Cu+ and ES in tumor cells induced the aggregation of lipoylated dihydrolipoamide S-acetyltransferase (DLAT) and the downregulation of Fe‒S cluster proteins, ultimately leading to cuproptosis. ES@Cu(Ⅱ)-MOF exhibited extraordinary cytotoxicity against breast cancer cells in vitro and significantly suppressed 4T1 breast tumor growth in vivo. Moreover, ES@Cu(Ⅱ)-MOF induced immunogenic cell death (ICD) to increase the antitumor immune response. Furthermore, combining ES@Cu(Ⅱ)-MOF with an anti-programmed cell death-ligand 1 (PD-L1) antibody converted the immunosuppressive tumor microenvironment to an immunogenic microenvironment, thus effectively inhibiting breast tumor growth. Overall, this work provides an innovative approach utilizing nanozymes to facilitate cuproptosis for cancer treatment, which potentially enhances the effectiveness of immune checkpoint inhibitor-based immunotherapy.

Cuproptosis and Cuproptosis-Based Synergistic Therapy for Cancer Treatment

Copper, as an essential trace nutrient for human, plays a crucial role in numerous cellular activities, and is vital for maintaining homeostasis in organisms. Deviations from normal intracellular copper concentration range can disrupt the cellular homeostasis and lead to cell death. Cell death is the process in which cells lose their vitality and cannot sustain normal metabolism, which has various forms. The recently discovered cuproptosis mechanism differs from the previously recognized forms, which is triggered by intracellular copper accumulation. The discovery of cuproptosis has sparked interest among researchers, and this mechanism has been applied in the treatment of various intractable diseases, including different types of cancer. However, the developed cuproptosis-based therapies have revealed certain limitations, such as low immunostimulatory efficiency, poor tumor targeting, and inhibition by the tumor microenvironment. Therefore, researchers are devoted to combining cuproptosis with existing cancer therapies to develop more effective synergistic cancer therapies. This review summarizes the latest research advancements in the cuproptosis-based therapies for various types of cancer, with a focus on the synergistic cancer therapies. Finally, it provides an outlook on the future development of cuproptosis in anti-tumor therapy.

Immunomodulatory metal-based biomaterials for cancer immunotherapy

Cancer immunotherapy, as an emerging cancer treatment approach, harnesses the patient's own immune system to effectively prevent tumor recurrence or metastasis. However, its clinical application has been significantly hindered by relatively low immune response rates. In recent years, metal-based biomaterials have been extensively studied as effective immunomodulators and potential tools for enhancing anti-tumor immune responses, enabling the reversal of immune suppression without inducing toxic side effects. This review introduces the classification of bioactive metal elements and summarizes their immune regulatory mechanisms. In addition, we discuss the immunomodulatory roles of biomaterials constructed from various metals, including aluminum, manganese, gold, calcium, zinc, iron, magnesium, and copper. More importantly, a systematic overview of their applications in enhancing immunotherapy is provided. Finally, the prospects and challenges of metal-based biomaterials with immunomodulatory functions in cancer immunotherapy are outlined.

Synergistic immunotherapy with a calcium-based nanoinducer: evoking pyroptosis and remodeling tumor-associated macrophages for enhanced antitumor immune response

The challenges posed by low immunogenicity and the immunosuppressive tumor microenvironment (TME) significantly hinder the efficacy of cancer immunotherapy. Pyroptosis, characterized as a pro-inflammatory cell death pathway, emerges as a promising approach to augment immunotherapy by promoting immunogenic cell death (ICD). The predominance of M2 phenotype tumor-associated macrophages (TAMs) in the TME underscores the critical need for TAM reprogramming to mitigate this immunosuppression. Herein, we introduce a calcium-based, intelligent-responsive nanoinducer (CaZCH NPs), designed to concurrently initiate pyroptosis and remodel TAMs, thereby amplifying antitumor immunotherapy effects. Modified with hyaluronic acid, CaZCH NPs can target tumor cells. Once internalized, CaZCH NPs respond to the acidic environment, releasing Ca2+, curcumin and H2O2 to induce mitochondrial Ca2+ overload and oxidation stress, leading to caspase-3/GSDME-mediated cell pyroptosis. Concurrently, O2 produced by CaZCH and pro-inflammatory cytokines from pyroptotic cells work together to shift TAM polarization towards the M1 phenotype, effectively countering TME's immunosuppressive effect. Notably, the synergistic effect of Ca2+-mediated pyroptosis and TAM remodeling demonstrates superior antitumor efficiency in colorectal cancer models. The induced ICD, coupled with M1-type TAMs, effectively enhances immunogenicity and mitigates immunosuppression, promoting dendritic cell maturation and activating CD8+ T cell-dependent systemic antitumor immunity. Our study presents a promising synergistic strategy for achieving highly efficient immunotherapy using a simple calcium-based nanoinducer.

Tumor Microenvironment-Activated In Situ Synthesis of Peroxynitrite for Enhanced Chemodynamic Therapy

Chemodynamic therapy (CDT) can induce cancer cell death through hydroxyl radicals (·OH) generated from Fenton or Fenton-like reactions. Compared with traditional therapies, CDT effectively overcomes inevitable drug resistance and exhibits low side effects. However, clinical application still faces challenges, primarily due to insufficient ·OH generation and the short-lifetime of ·OH in vivo. To address these challenges, we developed a peroxynitrite (ONOO-)-based CDT nanodrug (DOX@PMOF) composed of MOF-199, NO donor (PArg), and nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) activator (doxorubicin, DOX). In DOX@PMOF, MOF-199 serves as both a carrier for loading DOX and a source of Cu+ for triggering CDT. Upon uptake by cancer cells, the high concentration of glutathione (GSH) reduces MOF-199 to Cu+, which then reacts with H2O2 to generate ·OH. Moreover, the released DOX upregulates NOX4 expression, leading to the elevated H2O2 level and thereby promoting a high-efficiency Fenton-like reaction for sufficient ·OH generation. Subsequently, PArg generates abundant NO in response to the tumor microenvironment, leading to a cascade of NO and ·OH for the in situ synthesis of ONOO-. ONOO- is more toxic and has a longer lifetime and diffusion distance than ·OH, resulting in a more effective CDT treatment. To further enhance the in vivo therapeutic effect, we coated DOX@PMOF with a homologous cell membrane to form an active tumor-targeting nanodrug (DOX@MPMOF), which has demonstrated the ability to effectively inhibit tumor growth and metastasis while exhibiting good biosafety.

Cuproptosis: Advances in Stimulus-Responsive Nanomaterials for Cancer Therapy

Cuproptosis, a recently identified non-apoptotic programmed cell death modality, attracts considerable attention in the realm of cancer therapeutics owing to its unique cellular demise mechanisms. Since its initial report in 2022, strategies inducing or amplifying cuproptosis for cancer treatment emerge. The engineering of nano-systems to elicit cuproptosis effectively circumvents constraints associated with conventional small-molecule pharmaceutical interventions, presenting novel prospects for oncological therapy. Stimulus-responsive nanomaterials, leveraging their distinctive spatiotemporal control attributes, are investigated for their role in modulating the induction or augmentation of cuproptosis. In this comprehensive review, the physiological characteristics of cuproptosis, encompassing facets such as copper overload and depletion, coupled with regulatory factors intrinsic to cuproptosis, are expounded upon. Subsequently, design methodologies for stimulus-responsive induction or enhancement of cuproptosis, employing stimuli such as light, ultrasound, X-ray, and the tumor microenvironment, are systematically delineated. This review encompasses intricacies in nanomaterial design, insights into the therapeutic processes, and the associated advantages. Finally, challenges inherent in stimulus-responsive induction/enhancement of cuproptosis are deliberated upon and prospective insights into the future trajectory of copper-mediated cancer therapy are provided.

Metal-Organic Framework-Based Nanovaccine for Relieving Immunosuppressive Tumors via Hindering Efferocytosis of Macrophages and Promoting Pyroptosis and Cuproptosis of Cancer Cells

Current cancer vaccines face challenges due to an immunosuppressive tumor microenvironment and their limited ability to produce an effective immune response. To address the above limitations, we develop a 3-(2-spiroadamantyl)-4-methoxy-4-(3-phosphoryloxy)-phenyl-1,2-dioxetane (alkaline phosphatase substrate) and XMD8-92 (extracellular signal-regulated kinase 5 inhibitor)-codelivered copper-tetrahydroxybenzoquinone (Cu-THBQ/AX) nanosized metal-organic framework to in situ-generate therapeutic vaccination. Once inside the early endosome, the alkaline phosphatase overexpressed in the tumor cells' membrane activates the in situ type I photodynamic effect of Cu-THBQ/AX for generating •O2-, and the Cu-THBQ/AX catalyzes O2 and H2O2 to •O2- and •OH via semiquinone radical catalysis and Fenton-like reactions. This surge of ROS in early endosomes triggers caspase-3-mediated proinflammatory pyroptosis via activating phospholipase C. Meanwhile, Cu-THBQ/AX can also induce the oligomerization of dihydrolipoamide S-acetyltransferase to trigger tumor cell cuproptosis. The production of •OH could also trigger the release of XMD8-92 for effectively inhibiting the efferocytosis of macrophages to convert immunosuppressive apoptosis of cancer cells into proinflammatory secondary necrosis. The simultaneous induction of pyroptosis, cuproptosis, and secondary necrosis effectively converts the tumor microenvironment from "cold" to "hot" conditions, making it an effective antigen pool. This transformation successfully activates the antitumor immune response, inhibiting tumor growth and metastasis.