Fusiform-Like Copper(II)-Based Metal-Organic Framework through Relief Hypoxia and GSH-Depletion Co-Enhanced Starvation and Chemodynamic Synergetic Cancer Therapy

Advances in antitumor application of ROS enzyme-mimetic catalysts

The rapid growth of research on enzyme-mimetic catalysts (Enz-Cats) is expected to promote further advances in nanomedicine for biological detection, diagnosis and treatment of disease, especially tumors. ROS-based nanomedicines present fascinating potential in antitumor therapy owing to the rapid development of nanotechnology. In this review, we focus on the applications of Enz-Cats based on ROS in antitumor therapy. Firstly, the definition and category of ROS are introduced, and the key factors enhancing ROS levels are carefully elucidated. Then, the rationally engineered Enz-Cats via different synthetic approaches with high ROS-producing efficiencies are comprehensively discussed. Subsequently, oncotherapy application of Enz-Cats is comprehensively discussed, which integrates diverse synergistic treatment modalities and exhibits high efficiency in ROS generation. Finally, the challenges and future research direction of this field are presented. This review is dedicated to unraveling the enigmas surrounding the interplay of nanomedicine and organisms.

ROS mediated Cu[Fe(CN)5NO] nanoparticles for triple negative breast cancer: A detailed study in preclinical mouse model

Triple negative breast cancer (TNBC) is an aggressive form of tumor, more prevalent in younger women resulting in poor survival rate (2nd in cancer deaths) because of its asymptomatic existence. The most popular and convenient approach for the treatment of TNBC is chemotherapy which is associated with several limitations. Considering the importance of nanotechnology in health care system, in the present manuscript, we have designed and developed a simple, efficient, cost effective, and ecofriendly method for the synthesis of copper nitroprusside analogue nanoparticles (Cu[Fe(CN)5NO] which is abbreviated as CuNPANP that may be the potential anti-cancer nanomedicine for the treatment of TNBC. Copper (present in CuNPANP) is used because of its affordability, nutritional value and various biomedical applications. The CuNPANP are thoroughly characterized using several analytical techniques. The in vitro cell viability (in normal cells) and the ex vivo hemolysis assay reveal the biocompatible nature of CuNPANP. The anti-cancer activity of the CuNPANP is established in TNBC cells (MDA-MB-231 and 4T1) through several in vitro assays along with plausible mechanisms. The intraperitoneal administration of CuNPANP in orthotopic breast tumor model by transplanting 4T1 cells into the mammary fat pad of BALB/c mouse significantly inhibits the growth of breast carcinoma as well as increases the survival time of tumor-bearing mice. These results altogether potentiate the anti-cancer efficacy of CuNPANP as a smart therapeutic nanomedicine for treating TNBC in near future after bio-safety evaluation in large animals.

Multi-level Reactive Oxygen Species Amplifier to Enhance Photo-/Chemo-Dynamic/Ca2+ Overload Synergistic Therapy

Reactive oxygen species (ROS)-involved photodynamic therapy (PDT) and chemodynamic therapy (CDT) hold great promise for tumor treatment. However, hypoxia, insufficient H2O2, and overexpressed glutathione (GSH) in the tumor microenvironment (TME) hinder ROS generation significantly. Herein, we reported CaO2@Cu-TCPP/CUR with O2/H2O2/Ca2+ self-supply and GSH depletion for enhanced PDT/CDT and Ca2+ overload synergistic therapy. CaO2 nanospheres were first prepared and used as templates for guiding the coordination between the carboxyl of tetra-(4-carboxyphenyl)porphine (TCPP) and Cu2+ ions as hollow CaO2@Cu-TCPP, which facilitated GSH-activated TCPP-based PDT and Cu+-mediated CDT. The hollow structure was then loaded with curcumin (CUR) to form CaO2@Cu-TCPP/CUR composites. Cu-TCPP prevented degradation of CaO2, while Cu2+ ions reacted with GSH to deplete GSH, produce Cu+ ions, and release TCPP, CaO2, and CUR. CaO2 reacted with H2O to generate O2, H2O2, and Ca2+ to achieve O2/H2O2/Ca2+ self-supply for TCPP-based PDT, Cu+-mediated CDT, and CUR-enhanced Ca2+ overload therapy. Thus, this multilevel ROS amplifier enhances synergistic therapy with fewer side effects and drug resistance.

Russell Mechanism-Mediated Cancer Therapy: A Minireview

The Russell mechanism, proposed by Russell, is a cyclic mechanism for the formation of linear tetroxide intermediates, which can spontaneously produce cytotoxic singlet oxygen (1O2) independent of oxygen, suggesting its anticancer potential. Compared with other mainstream anticancer strategies, the Russell mechanism employed for killing cancer cells does not require external energy input, harsh pH condition, and sufficient oxygen. However, up till now, the applications of Russell mechanism in antitumor therapy have been relatively rare, and there is almost no summary of the Russell mechanism in the cancer therapy field. This minireview introduces the different metal elements-based Russell mechanisms and the relevant research progress in Russell mechanism-based cancer therapy in recent years. At the same time, we briefly discussed the current challenges and future development regarding the applications of Russell mechanism. It is hoped that this review can further expand the research of Russell Mechanism in the biomedical field, and inspire researchers to extend its application fields to antibacterial, antiinflammatory, and wound healing uses.

Enzyme-triggered on-demand release of a H2O2-self-supplying CuO2@Fe3O4 nanoagent for enhanced chemodyamic antimicrobial therapy and wound healing

Nanoagents for chemodynamic therapy (CDT) hold a promising future in the field of antimicrobials, especially copper peroxide (CuO2) (CP) nanomaterials which have garnered significant attention due to their ability to self-supply H2O2. Nevertheless, the poor stability of CuO2 remains a critical challenge which restricts its practical application in the antibacterial field. In this study, an advanced nano-antimicrobial system HA-CP@Fe3O4 with enzyme-responsive properties is developed by coating hyaluronic acid (HA) on CuO2-loaded iron tetraoxide nanoparticles. The coating of HA not only stabilizes the CuO2 nanomaterials but also provides responsiveness towards the enzyme hyaluronidase, which is typically secreted by some bacteria. The outer layer of HA in HA-CP@Fe3O4 undergoes decomposition in the presence of hyaluronidase-secreting bacteria, resulting in the release of CuO2@Fe3O4. The released CuO2@Fe3O4 then self-supplies H2O2 and generates reactive oxygen species (ROS) within the infected microenvironment through Fenton and Russell effects, to ultimately achieve effective and precise antimicrobial activity. Simultaneously, the magnetic property provided by Fe3O4 allows the substance to be directed towards the infection site. Both in vitro and in vivo tests demonstrated that HA-CP@Fe3O4 exhibited excellent antimicrobial capabilities at low concentration (30 μg mL-1), exceptional biocompatibility and the ability to accelerate wound healing. The findings of this work offer a new and promising approach for targeted and precise CDT.

Copper(II)-based metal-organic framework delivery of calcium ascorbate for enhanced chemodynamic therapy via H2O2 self-supply and glutathione depletion

Chemodynamic therapy (CDT) is a promising cancer treatment strategy. However, mild acidic pH, insufficient H2O2 content, and overexpressed glutathione (GSH) in the tumor microenvironment (TME) severely impair CDT efficiency. In this study, a novel therapeutic nanosystem (Cu/ZIF-8/Vc-Ca/HA) was constructed for H2O2 self-supply and GSH depletion co-enhanced CDT. Typically, calcium ascorbate (Vc-Ca) loaded on the surface of Cu2+-doped ZIF-8 (Cu/ZIF-8) was designed as an original source for H2O2 generation, and a hyaluronic acid (HA) shell was subsequently coated to act as a tumor-targeted "guide" and protective layer. Along with the HA shell disintegrated in the TME, exposed Cu/ZIF-8/Vc-Ca dissociated in the tumor acidic microenvironment, thus triggering the release of Vc-Ca and Cu2+. Vc-Ca selectively produced H2O2 in tumor cells, which provided abundant H2O2 for boosting Fenton-like reactions. Meanwhile, the released Cu2+ could get converted into Cu+ by consuming excess intracellular GSH, which could reduce the tumor antioxidant capability of the nanosystem. Moreover, byproduct Cu+ reacted with abundant H2O2 by a highly efficient Fenton-like reaction to generate toxic ˙OH. Biological assays indicated that the Cu/ZIF-8/HA@Vc-Ca nanosystem showed significant anticancer activity by enhancing the CDT process. This study may provide a new strategy for improving the effectiveness of CDT.

Biodegradable Metal Complex-Gated Organosilica for Dually Enhanced Chemodynamic Therapy through GSH Depletions and NIR Light-Triggered Photothermal Effects

Hollow silica spheres have been widely studied for drug delivery because of their excellent biosecurity and high porosity. However, difficulties with degradation in the tumor microenvironment (TME) and premature leaking during drug delivery limit their clinical applications. To alleviate these problems, herein, hollow organosilica spheres (HOS) were initially prepared using a "selective etching strategy" and loaded with a photothermal drug: new indocyanine green (IR820). Then, the Cu2+-tannic acid complex (Cu-TA) was deposited on the surface of the HOS, and a new nanoplatform named HOS@IR820@Cu-TA (HICT) was finally obtained. The deposition of Cu-TA can gate the pores of HOS completely to prevent the leakage of IR820 and significantly enhance the loading capacity of HOS. Once in the mildly acidic TME, the HOS and outer Cu-TA decompose quickly in response, resulting in the release of Cu2+ and IR820. The released Cu2+ can react with the endogenous glutathione (GSH) to consume it and produce Cu+, leading to the enhanced production of highly toxic ·OH through a Fenton-like reaction due to the overexpressed H2O2 in the TME. Meanwhile, the ·OH generation was remarkably enhanced by the NIR light-responsive photothermal effect of IR820. These collective properties of HICT enable it to be a smart nanomedicine for dually enhanced chemodynamic therapy through GSH depletions and NIR light-triggered photothermal effects.

Self-healable oxide sodium alginate/carboxymethyl chitosan nanocomposite hydrogel loading Cu2+-doped MOF for enhanced synergistic and precise cancer therapy

The limitations of traditional therapeutic methods such as chemotherapy serious restricted the application in tumor treatment, including poor targeting, toxic side effects and poor precision. It is important to develop non-chemotherapeutic systems to achieve precise and efficient tumor treatment. Therefore, a functional metal-organic framework material (MOF) with porphyrin core and doped with Cu2+ and surface-modified with polydopamine (PDA), namely PCN-224(Cu)@PDA (PCP) was designed and prepared. After loaded into the injectable and self-healable hydrogels by dynamic Schiff base bonding of oxidized sodium alginate (OSA) and carboxymethyl chitosan (CMC), the multifunctional nanocomposite hydrogels were obtained, in which Cu2+ in MOF converts to Cu+ by reacting with glutathione (GSH) which reduces the tumor antioxidant activity to improve the CDT effect. The Cu2+/Cu+ induces Fenton-like reaction in tumor cells to produce a toxic hydroxyl radical (OH). PDA achieves photothermal conversion under NIR light for photothermal therapy (PTT), and porphyrin core as a ligand generates reactive oxygen species (ROS), presenting highly efficient photodynamic therapy (PDT). Injectable self-healing hydrogel as a loading platform can be in situ injected to tumor site to release PCP and endocytosed by tumor cells to achieve precise and synergistic CDT-PDT-PTT therapy.

Recent advances in metal-organic frameworks for stimuli-responsive drug delivery

After entering the human body, drugs for treating diseases, which are prone to delivery and release in an uncontrolled manner, are affected by various factors. Based on this, many researchers utilize various microenvironmental changes encountered during drug delivery to trigger drug release and have proposed stimuli-responsive drug delivery systems. In recent years, metal-organic frameworks (MOFs) have become promising stimuli-responsive agents to release the loaded therapeutic agents at the target site to achieve more precise drug delivery due to their high drug loading, excellent biocompatibility, and high stimuli-responsiveness. The MOF-based stimuli-responsive systems can respond to various stimuli under pathological conditions at the site of the lesion, releasing the loaded therapeutic agent in a controlled manner, and improving the accuracy and safety of drug delivery. Due to the changes in different physical and chemical factors in the pathological process of diseases, the construction of stimuli-responsive systems based on MOFs has become a new direction in drug delivery and controlled release. Based on the background of the rapidly increasing attention to MOFs applied in drug delivery, we aim to review various MOF-based stimuli-responsive drug delivery systems and their response mechanisms to various stimuli. In addition, the current challenges and future perspectives of MOF-based stimuli-responsive drug delivery systems are also discussed in this review.

Bimetallic nanoplatform for synergistic sonodynamic-calcium overload therapy utilizing self-supplied hydrogen peroxide and relieved hypoxia

Sonodynamic therapy (SDT) has emerged as a potential alternative to traditional cancer treatments as it offers deep cellular penetration and reduced invasivity. Sonosensitizers generate reactive oxygen species (ROS) under ultrasound activation, focusing the ultrasound energy on malignant sites located deep in tissues and causing cell apoptosis and necrosis. However, due to tumor hypoxia and the limited levels of intracellular endogenous hydrogen peroxide (H2O2 is a fundamental species for supplying oxygen via catalase activity), SDT efficacy is still insufficient. In this study, a bimetallic and multifunctional system (Fe3O4-TAPP@PVP-CaO2) was prepared by using ferrosoferric oxide (Fe3O4) as a carrier loaded with 5,10,15,20-tetrakis(4-aminophenyl), porphyrin (TAPP), that was then coated with polyvinyl pyrrolidone (PVP) and calcium peroxide (CaO2). The CaO2 layer elevated the levels of H2O2 and Ca2+ in the tumor microenvironment when exposed to intracellular acidity, providing essential elements for oxygen generation. Intracellular hypoxia was alleviated via the catalase-like activity of Fe3O4 inducing calcium overload. Under ultrasonic irradiation, SDT generated toxic reactive oxygen species (ROS, singlet oxygen) and activated calcium influx through acoustic cavitation. Meanwhile, calcium overload therapy efficiently induced cell apoptosis at the moment of uncontrollable cellular accumulation of Ca2+. In addition, we modified the PVP on the surface to make it more stable. This study presents a bimetallic nanoplatform that can efficiently induce cancer cell death by synergistic sonodynamic-calcium overload therapy via modulation of O2/ROS/Ca2+ species, indicating its potential for multi-modality cancer therapy.

Intelligent Identification of Cerebrospinal Fluid for the Diagnosis of Parkinson's Disease

Cerebrospinal fluid (CSF) biomarkers are more sensitive than the Movement Disorder Society (MDS) criteria for detecting prodromal Parkinson's disease (PD). Early detection of PD provides the best chance for successful implementation of disease-modifying treatments, making it crucial to effectively identify CSF extracted from PD patients or normal individuals. In this study, an intelligent sensor array was built by using three metal-organic frameworks (MOFs) that exhibited varying catalytic kinetics after reacting with potential protein markers. Machine learning algorithms were used to process fingerprint response patterns, allowing for qualitative and quantitative assessment of the proteins. The results were robust and capable of discriminating between PD and non-PD patients via CSF detection. The k-nearest neighbor regression algorithm was used to predict MDS scores with a minimum mean square error of 38.88. The intelligent MOF sensor array is expected to promote the detection of CSF biomarkers due to its ability to identify multiple targets and could be used in conjunction with MDS criteria and other techniques to diagnose PD more sensitively and selectively.

DNA-functionalized metal or metal-containing nanoparticles for biological applications

The conjugation of DNA molecules with metal or metal-containing nanoparticles (M/MC NPs) has resulted in a number of new hybrid materials, enabling a diverse range of novel biological applications in nanomaterial assembly, biosensor development, and drug/gene delivery. In such materials, the molecular recognition, gene therapeutic, and structure-directing functions of DNA molecules are coupled with M/MC NPs. In turn, the M/MC NPs have optical, catalytic, pore structure, or photodynamic/photothermal properties, which are beneficial for sensing, theranostic, and drug loading applications. This review focuses on the different DNA functionalization protocols available for M/MC NPs, including gold NPs, upconversion NPs, metal-organic frameworks, metal oxide NPs and quantum dots. The biological applications of DNA-functionalized M/MC NPs in the treatment or diagnosis of cancers are discussed in detail.

Immobilization of horseradish peroxidase on metal-organic framework to imporve enzyme activity for enhanced chemodynamic therapy

Bio-enzymes have the advantages of strong substrate specificity, high catalytic efficiency, and minimal toxic side effects, making them promising drugs in cancer therapy. However, the poor stability and cellular penetrability of uncoated protein in the physiological environment severely restricts the direct application of Bio-enzyme. To address it, we report a metal-organic framework (MOF), Hf-DBA (H2DBA, biphenyl carboxylic acid ligands). The morphology of the Hf-DBA was revealed by TEM and the diameter was in the range of 200 to 350 nm. Hf-DBA acted a carrier for intracellular delivery and protection of horseradish peroxidase (HRP). The prepared HRP@Hf-DBA can catalyze the excess H2O2 in the tumor cells to generation of •OH for chemodynamic therapy (CDT). Compared with free HRP, the catalytic activity of HRP@Hf-DBA is significantly improved, and the optimal catalytic conditions are explored. The catalytic stability of HRP@Hf-DBA remained above 70% after 12 cycles of catalysis. After treatment with HRP@Hf-DBA, the apoptosis rates of A549 and Hela cells was 71.64%, and 76.86%. The results in vitro show that HRP@Hf-DBA can effectively inhibit the growth of tumor cells through enhanced CDT.

Cuproptosis: A novel therapeutic target for overcoming cancer drug resistance

Cuproptosis is a newly identified form of cell death driven by copper. Recently, the role of copper and copper triggered cell death in the pathogenesis of cancers have attracted attentions. Cuproptosis has garnered enormous interest in cancer research communities because of its great potential for cancer therapy. Copper-based treatment exerts an inhibiting role in tumor growth and may open the door for the treatment of chemotherapy-insensitive tumors. In this review, we provide a critical analysis on copper homeostasis and the role of copper dysregulation in the development and progression of cancers. Then the core molecular mechanisms of cuproptosis and its role in cancer is discussed, followed by summarizing the current understanding of copper-based agents (copper chelators, copper ionophores, and copper complexes-based dynamic therapy) for cancer treatment. Additionally, we summarize the emerging data on copper complexes-based agents and copper ionophores to subdue tumor chemotherapy resistance in different types of cancers. We also review the small-molecule compounds and nanoparticles (NPs) that may kill cancer cells by inducing cuproptosis, which will shed new light on the development of anticancer drugs through inducing cuproptosis in the future. Finally, the important concepts and pressing questions of cuproptosis in future research that should be focused on were discussed. This review article suggests that targeting cuproptosis could be a novel antitumor therapy and treatment strategy to overcome cancer drug resistance.

Glucose-primed PEEK orthopedic implants for antibacterial therapy and safeguarding diabetic osseointegration

Diabetic infectious microenvironment (DIME) frequently leads to a critical failure of osseointegration by virtue of its main peculiarities including typical hyperglycemia and pathogenic infection around implants. To address the plaguing issue, we devise a glucose-primed orthopedic implant composed of polyetheretherketone (PEEK), Cu-chelated metal-polyphenol network (hauberk coating) and glucose oxidase (GOx) for boosting diabetic osseointegration. Upon DIME, GOx on implants sostenuto consumes glucose to generate H2O2, and Cu liberated from hauberk coating catalyzes the H2O2 to highly germicidal •OH, which massacres pathogenic bacteria through photo-augmented chemodynamic therapy. Intriguingly, the catalytic efficiency of the coating gets greatly improved with the turnover number (TON) of 0.284 s-1. Moreover, the engineered implants exhibit satisfactory cytocompatibility and facilitate osteogenicity due to the presence of Cu and osteopromotive polydopamine coating. RNA-seq analysis reveals that the implants enable to combat infections and suppress pro-inflammatory phenotype (M1). Besides, in vivo evaluations utilizing infected diabetic rat bone defect models at week 4 and 8 authenticate that the engineered implants considerably elevate osseointegration through pathogen elimination, inflammation dampening and osteogenesis promotion. Altogether, our present study puts forward a conceptually new tactic that arms orthopedic implants with glucose-primed antibacterial and osteogenic capacities for intractable diabetic osseointegration.

Multiple therapeutic mechanisms of pyrrolic N-rich g-C3N4 nanosheets with enzyme-like function in the tumor microenvironment

Nanozyme-based synergistic catalytic therapies for tumors have attracted extensive research attention. However, the unsatisfactory efficiency and negative impact of the tumor microenvironment (TME) hinder its clinical applications. In this study, we provide an easy method to prepare transition metals loaded onto pyrrolic nitrogen-rich g-C3N4 (PN-g-C3N4) for forming metal-N4 sites. This N-rich material effectively transfers electrons from g-C3N4 to metal-N4 sites, promotes the oxidation-reduction reaction of metals with different valence states, and improves material reusability. Under TME conditions, copper ions loaded onto PN-g-C3N4 (Cu-PN-g-C3N4, CPC) can produce ·OH through a Fenton-like reaction for tumor inhibition. This Fenton-like reaction and tumor cell inhibition can be improved further by a photodynamic effect caused by light irradiation. We introduced upconversion nanoparticles (UCNPs) into CPC to obtain nano-enzymes (UCNPs@Cu-PN-g-C3N4, UCPC) for effectively penetrating the tissue, which emits light corresponding to the UV absorption region of CPC when excited with 980 nm near-infrared (NIR) light. The nanoplatform can reduce H2O2 concentration upon exposure to NIR light; this induces an increase in dissolved oxygen content and produces a higher supply of reactive oxygen species (ROS) for destroying tumor cells. Owing to the narrow bandgap (1.92 eV) of UCPC under 980 light irradiation, even under the condition of hypoxia, the excited electrons in the conduction band can reduce insoluble O2 through a single electron transfer process, thus effectively generating O2•-. Nanoenzyme materials with catalase properties produce three types of ROS (·OH, O2•- and 1O2) when realizing chemodynamic and photodynamic therapies. An excellent therapeutic effect was established by killing cells in vitro and the tumor-inhibiting effect in vivo, proving that the prepared nanoenzymes have an effective therapeutic effect and that the endogenous synergistic treatment of multiple treatment technologies can be realized.

Metal-organic framework-modulated Fe3O4 composite au nanoparticles for antibacterial wound healing via synergistic peroxidase-like nanozymatic catalysis

Bacterial wound infections are a serious threat due to the emergence of antibiotic resistance. Herein, we report an innovative hybrid nanozyme independent of antibiotics for antimicrobial wound healing. The hybrid nanozymes are fabricated from ultra-small Au NPs via in-situ growth on metal-organic framework (MOF)-stabilised Fe3O4 NPs (Fe3O4@MOF@Au NPs, FMA NPs). The fabricated hybrid nanozymes displayed synergistic peroxidase (POD)-like activities. It showed a remarkable level of hydroxyl radicals (·OH) in the presence of a low dose of H2O2 (0.97 mM). Further, the hybrid FMA nanozymes exhibited excellent biocompatibility and favourable antibacterial effects against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. The animal experiments indicated that the hybrid nanozymes promoted wound repair with adequate biosafety. Thus, the well-designed hybrid nanozymes represent a potential strategy for healing bacterial wound infections, without any toxic side effects, suggesting possible applications in antimicrobial therapy.

Mn2+ /Ir3+ -Doped and CaCO3 -Covered Prussian Blue Nanoparticles with Indocyanine Green Encapsulation for Tumor Microenvironment Modulation and Image-Guided Synergistic Cancer Therapy

The development of smart theranostic nanoplatforms has gained great interest in effective cancer treatment against the complex tumor microenvironment (TME), including weak acidity, hypoxia, and glutathione (GSH) overexpression. Herein, a TME-responsive nanoplatform named PMICApt /ICG, based on PB:Mn&Ir@CaCO3 Aptamer /ICG, is designed for the competent synergistic photothermal therapy and photodynamic therapy (PDT) under the guidance of photothermal and magnetic resonance imaging. The nanoplatform's aptamer modification targeting the transferrin receptor and the epithelial cell adhesion molecule on breast cancer cells, and the acid degradable CaCO3 shell allow for effective tumor accumulation and TME-responsive payload release in situ. The nanoplatform also exhibits excellent PDT properties due to its ability to generate O2 and consume antioxidant GSH in tumors. Additionally, the synergistic therapy is achieved by a single wavelength of near-infrared laser. RNA sequencing is performed to identify differentially expressed genes, which show that the expressions of proliferation and migration-associated genes are inhibited, while the apoptosis and immune response gene expressions are upregulated after the synergistic treatments. This multifunctional nanoplatform that responds to the TME to realize the on-demand payload release and enhance PDT induced by TME modulation holds great promise for clinical applications in tumor therapy.

Tunable metal-organic frameworks assist in catalyzing DNAzymes with amplification platforms for biomedical applications

Various binding modes of tunable metal organic frameworks (MOFs) and functional DNAzymes (Dzs) synergistically catalyze the emergence of abundant functional nanoplatforms. Given their serial variability in formation, structural designability, and functional controllability, Dzs@MOFs tend to be excellent building blocks for the precise "intelligent" manufacture of functional materials. To present a clear outline of this new field, this review systematically summarizes the progress of Dz integration into MOFs (MOFs@Dzs) through different methods, including various surface infiltration, pore encapsulation, covalent binding, and biomimetic mineralization methods. Atomic-level and time-resolved catalytic mechanisms for biosensing and imaging are made possible by the complex interplay of the distinct molecular structure of Dzs@MOF, conformational flexibility, and dynamic regulation of metal ions. Exploiting the precision of DNAzymes, MOFs@Dzs constructed a combined nanotherapy platform to guide intracellular drug synthesis, photodynamic therapy, catalytic therapy, and immunotherapy to enhance gene therapy in different ways, solving the problems of intracellular delivery inefficiency and insufficient supply of cofactors. MOFs@Dzs nanostructures have become excellent candidates for biosensing, bioimaging, amplification delivery, and targeted cancer gene therapy while emphasizing major advancements and seminal endeavors in the fields of biosensing (nucleic acid, protein, enzyme activity, small molecules, and cancer cells), biological imaging, and targeted cancer gene delivery and gene therapy. Overall, based on the results demonstrated to date, we discuss the challenges that the emerging MOFs@Dzs might encounter in practical future applications and briefly look forward to their bright prospects in other fields.

Manganese-Based Nanotheranostics for Magnetic Resonance Imaging-Mediated Precise Cancer Management

Manganese (Mn)-based magnetic resonance imaging (MRI) has become a competitive imaging modality for cancer diagnosis due to its advantages of non-invasiveness, high resolution and excellent biocompatibility. In recent years, a variety of Mn contrast agents based on different material systems have been synthesized, and a series of multi-purpose Mn nanocomposites have also emerged, showing satisfactory relaxation efficiency and MRI performance thus possess the transformation and application value in MRI-synergized cancer diagnosis and treatment. This tutorial review starts from the classification and properties of Mn-based nanomaterials, and then summarizes various preparation and functionalization strategies of nanosized Mn contrast agents, especially focuses on the latest progress of Mn contrast agents in MRI-synergized precise cancer theranostics. In addition, present review also discusses the current clinical transformation obstacles such as unclear molecular mechanisms, potential nanotoxicity, and scale production constraints. This paper provides evidence-based recommendations about the future prospects of multifunctional nanoplatforms, as well as technical guidance and panoramic expectations for the design of clinically meaningful cancer management programs.

Copper(II)-MOFs for bio-applications

The recent development and implementation of copper-based metal-organic frameworks in biological applications are reviewed. The advantages of the presence of copper in MOFs for relevant applications such as drug delivery, cancer treatment, sensing, and antimicrobial are highlighted. Advanced composites such as MOF-polymers are playing critical roles in developing materials for specific applications.

Photoelectrochemical detection of superoxide anions released from mitochondria in HepG2 cells based on the synergistic effect of MnO2@Co3O4 core-shell p-n heterojunction

The detection and comparison of the amount of superoxide anion (O2.-) released by different complexes in mitochondrial electron transport chain (ETC) can locate the main electron leakage sites in mitochondria. In order to realize this, we designed an ultrasensitive photoelectrochemical (PEC) sensor by in situ hydrothermal growth of MnO2 nanosheets on Co3O4 nanowires array modified Ti substrate (NWA|Ti). Due to the formation of a core-shell p-n heterojunction with high specific surface area, tight surface contact and plentiful oxygen vacancies (OVs), MnO2@Co3O4 NWA|Ti possesses a strong visible light absorption, high charges transfer and separation ability. The proposed PEC sensor exhibited a wide linear range of 0.1-50000 nM and a low detection limit of 0.025 nM towards H2O2. Due to the rapid conversion of O2.- to H2O2 inside mitochondria, the PEC sensor can indirectly monitor the electron leakage in the ETC. Specifically, four selected mitochondrial inhibitors specifically inhibited the corresponding complex in mitochondria extracted from living HepG2 cells (hepatocellular carcinoma cells), and the H2O2 levels converted from O2.- was measured by the PEC sensor. It is evident that IQ (ubiquinone binding) site of complex I and Qo (ubiquinol oxidation) site of complex III are the key sites at which electron leakage occurred. This study could provide meaningful information for the diagnosis and treatment of certain disease caused by oxidative stress due to the electron leakage.

Multifaceted Roles of Copper Ions in Anticancer Nanomedicine

The significantly increased copper level in tumor tissues and serum indicates the close association of copper ions with tumor development, making copper ions attractive targets in the development of novel tumor treatment methods. The advanced nanotechnology developed in the past decades provides great potential for tumor therapy, among which Cu-based nanotherapeutic systems have received greater attention. Herein, the multifaceted roles of copper ions in cancer progression are summarized and the recent advances in the copper-based nanostructures or nanomedicines for different kinds of tumor therapies including copper depletion therapy, copper-based cytotoxins, copper-ion-based chemodynamic therapy and its combination with other treatments, and copper-ion-induced ferroptosis and cuproptosis activation are discussed. Furthermore, the perspectives for the further development of copper-ion-based nanomedicines for tumor therapy and clinic translation are presented by the authors.

Multifunctional CuFe2O4@HA as a GSH-depleting nanoplatform for targeted photothermal/enhanced-chemodynamic synergistic therapy

Chemodynamic therapy (CDT), which converts overexpressed hydrogen peroxide (H2O2) in tumor cells to hydroxyl radicals (•OH) by Fenton reactions, is considered a prospective strategy in anticancer therapy. However, the high level of glutathione (GSH) and poor Fenton catalytic efficiency contribute to the suboptimal efficiency of CDT. Herein, we present a multifunctional nanoplatform (CuFe2O4@HA) that can induce GSH depletion and combine with photothermal therapy (PTT) to enhance antitumor efficacy. CuFe2O4@HA nanoparticles could release Cu2+ and Fe3+ after entering tumor cells by targeting hyaluronic acid (HA). Subsequently, Cu2+ and Fe3+ were reduced to Cu+ and Fe2+ by GSH, where Cu+/Fe2+ significantly catalyzed H2O2 to produce a higher level of •OH, and the depletion of GSH disrupted the antioxidant capacity of the tumor. Therefore, depleting GSH substantially enhances the level of •OH in tumor cells. In addition, CuFe2O4@HA nanoparticles have considerable absorption in the near-infrared (NIR) region, which can stimulate excellent PTT effects. More importantly, the heat generated by PTT can further enhance the Fenton catalysis efficiency. In vitro and in vivo experiments have demonstrated the excellent tumor-killing effect of CuFe2O4@HA nanoparticles. This strategy overcomes the problem of insufficient CDT efficacy caused by GSH overexpression and poor catalytic efficiency. Moreover, this versatile nanoplatform provides a reference for self-enhanced CDT and PTT/CDT synergistic targeted therapy.

Current status of porous coordination networks (PCNs) derived porphyrin spacers for cancer therapy

INTRODUCTION

Porous coordination networks (PCNs) have been widely used in large number of applications such as light harvesting, catalysis, and biomedical applications. Inserting porphyrins into PCNs scaffolds can alleviate the solubility and chemical stability problems associated with porphyrin ligands and add functionality to PCNs. The discovery that some PCNs materials have photosensitizer and acoustic sensitizer properties has attracted significant attention in the field of biomedicine, particularly in cancer therapy. This article describes the latest applications of the porphyrin ligand-based family of PCNs in cancer chemodynamic therapy (CDT), photodynamic therapy (PDT), sonodynamic therapy (SDT), photothermal therapy (PTT), and combination therapies and offers some observations and reflections on them.

AREAS COVERED

This article discusses the use of the PCN family of MOFs in cancer treatment, specifically focusing on chemodynamic therapy, sonodynamic therapy, photodynamic therapy, photothermal therapy, and combination therapy.

EXPERT OPINION

Although a large number of PCNs have been developed for use in novel cancer therapeutic approaches, further improvements are needed to advance the use of PCNs in the clinic. For example, the main mechanism of action of PCNs against cancer and the metabolic processes in organisms, and how to construct PCNs that maintain good stability in the complex environment of organisms.

Development of the Cu/ZIF-8 MOF Acid-Sensitive Nanocatalytic Platform Capable of Chemo/Chemodynamic Therapy with Improved Anti-Tumor Efficacy

Recently, the combination of chemotherapy and chemodynamic therapy (CDT) has become a desirable strategy in the treatment of cancer. However, a satisfactory therapeutic outcome is often difficult to achieve due to the deficiency of endogenous H₂O₂ and O₂ in the tumor microenvironment. In this study, a CaO₂@DOX@Cu/ZIF-8 nanocomposite was prepared as a novel nanocatalytic platform to enable the combination of chemotherapy and CDT in cancer cells. The anticancer drug doxorubicin hydrochloride (DOX) was loaded onto calcium peroxide (CaO₂) nanoparticles (NPs) to form CaO₂@DOX, which was then encapsulated in a copper zeolitic imidazole ester MOF (Cu/ZIF-8) to form CaO₂@DOX@Cu/ZIF-8 NPs. In the mildly acidic tumor microenvironment, CaO₂@DOX@Cu/ZIF-8 NPs rapidly disintegrated, releasing CaO₂, which reacted with water to generate H₂O₂ and O₂ in the tumor microenvironment. The ability of CaO₂@DOX@Cu/ZIF-8 NPs to combine chemotherapy and CDT was assessed by conducting cytotoxicity, living dead staining, cellular uptakes, H&E staining, and TUNEL assays in vitro and in vivo. The combination of chemotherapy and CDT of CaO₂@DOX@Cu/ZIF-8 NPs had a more favorable tumor suppression effect than the nanomaterial precursors, which were not capable of the combined chemotherapy/CDT.

A hybrid nanopharmaceutical for specific-amplifying oxidative stress to initiate a cascade of catalytic therapy for pancreatic cancer

BACKGROUND

Oxidative stress (OS) induced by an imbalance of oxidants and antioxidants is an important aspect in anticancer therapy, however, as an adaptive response, excessive glutathione (GSH) in the tumor microenvironment (TME) acts as an antioxidant against high reactive oxygen species (ROS) levels and prevents OS damage to maintain redox homoeostasis, suppressing the clinical efficacy of OS-induced anticancer therapies.

RESULTS

A naturally occurring ROS-activating drug, galangin (GAL), is introduced into a Fenton-like catalyst (SiO₂@MnO₂) to form a TME stimulus-responsive hybrid nanopharmaceutical (SiO₂-GAL@MnO₂, denoted SG@M) for enhancing oxidative stress. Once exposed to TME, as MnO₂ responds and consumes GSH, the released Mn²⁺ converts endogenous hydrogen peroxide (H₂O₂) into hydroxyl radicals (·OH), which together with the subsequent release of GAL from SiO₂ increases ROS. The "overwhelming" ROS cause OS-mediated mitochondrial malfunction with a decrease in mitochondrial membrane potential (MMP), which releases cytochrome c from mitochondria, activates the Caspase 9/Caspase 3 apoptotic cascade pathway. Downregulation of JAK2 and STAT3 phosphorylation levels blocks the JAK2/STAT3 cell proliferation pathway, whereas downregulation of Cyclin B1 protein levels arrest the cell cycle in the G2/M phase. During 18 days of in vivo treatment observation, tumor growth inhibition was found to be 62.7%, inhibiting the progression of pancreatic cancer. Additionally, the O₂ and Mn²⁺ released during this cascade catalytic effect improve ultrasound imaging (USI) and magnetic resonance imaging (MRI), respectively.

CONCLUSION

This hybrid nanopharmaceutical based on oxidative stress amplification provides a strategy for multifunctional integrated therapy of malignant tumors and image-visualized pharmaceutical delivery.

Bionic natural small molecule co-assemblies towards targeted and synergistic Chemo/PDT/CDT

BACKGROUND

Multi-component nano-delivery systems based on chemotherapy (chemo)- photodynamic therapy (PDT)- chemodynamic therapy (CDT) have gained increased attention as a promising strategy to improve clinical outcomes in cancer treatment. However, there remains a challenge in developing biodegradable, biocompatible, less toxic, yet highly efficient multicomponent nanobased drug delivery systems (DDS). Here, our study presents the screening and development of a novel DDS based on co-assemblies natural small molecule (NSMs). These molecules (oleanolic acid, and betulinic acid) are combined with photosensitizers Chlorine6 (Ce6) and Cu²⁺ that are encapsulated by tumor cell membranes. This nanocarrier encapsulated in tumor cell membranes achieved good tumor targeting and a significant improvement in tumor accumulation.

METHODS

A reprecipitation method was used to prepare the co-assembled nanocarrier, followed by the introduction of Cu^2 + into the DDS (OABACe6 NPs). Then, by wrapping the surface of NPs with the cell membranes of 4T1 which is a kind of mouse breast cancer cells (CM@OABACe6/Cu NPs). and analysis of its structure and size distribution with UV-Vis, XPS, FT-IR, SEM, TEM, and DLS. The synergistic effects of in vitro chemotherapy, CDT and PDT and targeting were also validated by cellular and animal studies.

RESULTS

It was shown that CM@OABACe6/Cu NPs achieved good tumor targeting and a significant improvement in tumor accumulation. In the composite nano-assembly, the NSMs work together with the Ce6 to provide effective and safe chemo and PDT. Moreover, the effect of reduced PDT due to the depletion of reactive oxygen species (ROS) by excess glutathione (GSH) in the tumor can be counteracted when Cu^2 + is introduced. More importantly, it also confers CDT through a Fenton-like catalytic reaction with H₂O overexpressed at the tumor site.

CONCLUSIONS

By constructing CM@OABACe6/Cu NPs with homologous targeting, we create a triple synergistic platform for cancer therapy using PDT, chemo, and CDT. We propose here a novel combinatorial strategy for designing more naturally co-assembled small molecules, especially for the development of multifunctional synergistic therapies that utilize NSMs.

Recent advances in nanoscale metal-organic frameworks for cancer chemodynamic therapy

Chemodynamic therapy (CDT), a novel therapeutic approach based on Fenton (Fenton-like) reaction, has been widely employed for tumor therapy. This approach utilizes Fe, Cu, or other metal ions (Mn, Zn, Co, or Mo) to react with the excess hydrogen peroxide (H₂O₂) in tumor microenvironments (TME), and form highly cytotoxic hydroxyl radical (˙OH) to kill cancer cells. Recently, nanoscale metal-organic frameworks (nMOFs) have attracted considerable attention as promising CDT agents with the rapid development of cancer CDT. This review focuses on summarizing the latest advances (2020-2022) on the design of nMOFs as nanomedicine for CDT or combination therapy of CDT and other therapies. The future development and challenges of CDT are also proposed based on recent progress. Our group hopes that this review will enlighten the research and development of nMOFs for CDT.

Poly-thymine DNA templated MnO2 biomineralization as a high-affinity anchoring enabling tumor targeting delivery

Manganese oxide nanomaterials (MONs) are emerging as a type of highly promising nanomaterials for diseases diagnosis, and surface modification is the basis for colloidal stability and targeting delivery of the nanomaterials. Here, we report the in-situ functionalization of MnO₂ with DNA through a biomineralization process. Using adsorption-oxidation method, DNA templated Mn²⁺ precursor to biomineralize into nano-cubic seed, followed by the growth of MnO₂ to form cube/nanosheet hybrid nanostructure. Among four types of DNA homopolymers, poly-thymine (poly-T) was found to stably attach on MnO₂ surface to resist various biological displacements (phosphate, serum, and complementary DNA). Capitalized on this finding, a di-block DNA was rationally designed, in which the poly-T block stably anchored on MnO₂ surface, while the AS1411 aptamer block was not only an active ligand for tumor targeting delivery, but also a carrier for photosensitizer (Ce6) loading. Upon targeting delivery into tumor cells, the MnO₂ acted as catalase-mimic nanozyme for oxygenation to sensitize photodynamic therapy, and the released Mn²⁺ triggered chemodynamic therapy via Fenton-like reaction, achieving synergistic anti-tumor effect with full biocompatibility. This work provides a simple yet robust strategy to functionalize metal oxides nanomaterials for biological applications via DNA-templated biomineralization.

Intelligent Pd1.7Bi@CeO2 Nanosystem with Dual-Enzyme-Mimetic Activities for Cancer Hypoxia Relief and Synergistic Photothermal/Photodynamic/Chemodynamic Therapy

Reactive oxygen species-mediated therapeutic strategies, including chemodynamic therapy (CDT) and photodynamic therapy (PDT), have exhibited translational promise for effective cancer management. However, monotherapy often ends up with the incomplete elimination of the entire tumor due to inherent limitations. Herein, we report a core-shell-structured Pd_1.7Bi@CeO₂-ICG (PBCI) nanoplatform constructed by a facile and effective strategy for synergistic CDT, PDT, and photothermal therapy. In the system, both Pd_1.7Bi and CeO₂ constituents exhibit peroxidase- and catalase-like characteristics, which not only generate cytotoxic hydroxyl radicals (^•OH) for CDT but also produce O₂ in situ and relieve tumor hypoxia for enhanced PDT. Furthermore, upon 808 nm laser irradiation, Pd_1.7Bi@CeO₂ and indocyanine green (ICG) coordinately prompt favorable photothermia, resulting in thermodynamically amplified catalytic activities. Meanwhile, PBCI is a contrast agent for near-infrared fluorescence imaging to determine the optimal laser therapeutic window in vivo. Consequently, effective tumor elimination was realized through the above-combined functions. The as-synthesized unitary PBCI theranostic nanoplatform represents a potential one-size-fits-all approach in multimodal synergistic therapy of hypoxic tumors.

Nanoscale metal-organic framework delivers rapamycin to induce tissue immunogenic cell death and potentiates cancer immunotherapy

Rapamycin has great potential in the antitumor application, but its therapeutic effect is seriously affected by poor water solubility, targeting ability, and low bioavailability. Here, we constructed a novel composite nanomaterial with PCN-224 as a drug carrier and loaded rapamycin, named R@BP@HA. The nanoplate not only improves targeting, but also synergizes rapamycin with PCN-224 to effectively promote tumor cell apoptosis, which subsequently causes immunogenic cell death (ICD), and shows strong therapeutic effect in 4T1 breast cancer model. The treatment effect depends on three main points:(i)Proapoptotic effect of rapamycin on tumor cells;(ii)ROS production by PCN-224-mediated photodynamic therapy;(iii)ICD induced DC maturation, increased immune response and promoted T cell proliferation and differentiation. This nanoplate offers potential antitumor efficacy in combination with chemotherapy, photodynamic therapy, and immunotherapy.

Aptamer modified Zr-based porphyrinic nanoscale metal-organic frameworks for active-targeted chemo-photodynamic therapy of tumors

Active-targeted nanoplatforms could specifically target tumors compared to normal cells, making them a promising therapeutic agent. The aptamer is a kind of short DNA or RNA sequence that can specifically bind to target molecules, and could be widely used as the active targeting agents of nanoplatforms to achieve active-targeted therapy of tumors. Herein, an aptamer modified nanoplatform DOX@PCN@Apt-M was designed for active-targeted chemo-photodynamic therapy of tumors. Zr-based porphyrinic nanoscale metal organic framework PCN-224 was synthesized through a one-pot reaction, which could produce cytotoxic ¹O₂ for efficient treatment of tumor cells. To improve the therapeutic effect of the tumor, the anticancer drug doxorubicin (DOX) was loaded into PCN-224 to form DOX@PCN-224 for tumor combination therapy. Active-targeted combination therapy achieved by modifying the MUC1 aptamer (Apt-M) onto DOX@PCN-224 surface can not only further reduce the dosage of therapeutic agents, but also reduce their toxic and side effects on normal tissues. In vitro, experimental results indicated that DOX@PCN@Apt-M exhibited enhanced combined therapeutic effect and active targeting efficiency under 808 nm laser irradiation for MCF-7 tumor cells. Based on PCN-224 nanocarriers and aptamer MUC1, this work provides a novel strategy for precisely targeting MCF-7 tumor cells.

Starvation-assisted and photothermal-thriving combined chemo/chemodynamic cancer therapy with PT/MR bimodal imaging

Chemodynamic therapy (CDT) reflects a novel reactive oxygen species (ROS)-related cancer therapeutic approach. However, CDT monotherapy is often limited by weak efficacy and insufficient endogenous H₂O₂. Herein, a multifunctional combined bioreactor (MnFe-LDH/MTX@GOx@Ta, MMGT) relying on MnFe-layered double hydroxide (MnFe-LDH) loaded with methotrexate (MTX) and coated with glucose oxidase (GOx)/tannin acid (Ta) is established for applications in H₂O₂ self-supply and photothermal enhanced chemo/chemodynamic combined therapy along with photothermal (PT) /magnetic resonance (MR) dual-modality imaging ability for cancer treatment. Once internalized into tumor cells, MMGT achieves starvation therapy by catalyzing the oxidation of glucose with GOx, accompanied by the regeneration of H₂O₂, enabling a Fenton-like reaction to accomplish GOx catalytic amplified CDT. Moreover, MMGT manifests significant tumor-killing ability through improved CDT performance with outstanding photothermal conversion efficiency (η = 52.2%) under 808 nm laser irradiation. In addition, the release of Mn²⁺ from MnFe-LDH in a solid tumor can significantly enhance T₁-contrast MR imaging signals. Combined with MnFe-LDH-induced PT imaging under 808 nm laser irradiation, a dual-modality imaging directed theranostic nanoplatform has been developed. The present study provides a new strategy to design H₂O₂ self-supply and ROS evolving NIR light-absorption theranostic nanoagent for highly efficient and combined chemo/chemodynamic cancer treatment.

Copper(II) complex enhanced chemodynamic therapy through GSH depletion and autophagy flow blockade

Three copper(II) complexes C1-C3 were synthesized and fully characterized as chemodynamic therapy (CDT) anticancer agents. C1-C3 showed greater cytotoxicity than their ligands toward SK-OV-3 and T24 cells. Particularly, C2 showed high cytotoxicity toward T24 cells and low cytotoxicity toward normal human HL-7702 and WI-38 cells. Mechanistic studies demonstrated that C2 oxidized GSH to GSSG and produced ˙OH, which induced mitochondrial dysfunction and ER stress, finally leading to apoptosis of T24 cells. In addition, C2 inhibited autophagy by blocking autophagy flow, thereby closing the self-protection pathway of oxidative stress to enhance CDT. Importantly, C2 significantly inhibited T24 tumor growth with 57.1% inhibition in a mouse xenograft model. C2 is a promising lead as a potential CDT anticancer agent.

H2O2 Self-Supplying and GSH-Depleting Nanocatalyst for Copper Metabolism-Based Synergistic Chemodynamic Therapy and Chemotherapy

Chemodynamic therapy (CDT) that involves the use of Fenton catalysts to convert endogenous hydrogen peroxide (H₂O₂) to hydroxyl radicals (·OH) constitutes a promising strategy for cancer therapy; however, insufficient endogenous H₂O₂ and glutathione (GSH) overexpression render its efficiency unsatisfactory. Herein, we present an intelligent nanocatalyst that comprises copper peroxide nanodots and DOX-loaded mesoporous silica nanoparticles (MSNs) (DOX@MSN@CuO₂) and can self-supply exogenous H₂O₂ and respond to specific tumor microenvironments (TME). Following endocytosis into tumor cells, DOX@MSN@CuO₂ initially decomposes into Cu²⁺ and exogenous H₂O₂ in the weakly acidic TME. Subsequently, Cu²⁺ reacts with high GSH concentrations, thereby inducing GSH depletion and reducing Cu²⁺ to Cu⁺ Next, the generated Cu⁺ undergoes Fenton-like reactions with exogenous H₂O₂ to accelerate toxic ·OH production, which exhibits a rapid reaction rate and is responsible for tumor cell apoptosis, thereby enhancing CDT. Furthermore, the successful delivery of DOX from the MSNs achieves chemotherapy and CDT integration. Thus, this excellent strategy can resolve the problem of insufficient CDT efficacy due to limited H₂O₂ and GSH overexpression. Integrating H₂O₂ self-supply and GSH deletion enhances CDT, and DOX-induced chemotherapy endows DOX@MSN@CuO₂ with effective tumor growth-inhibiting properties alongside minimal side effects in vivo.

Glucose Oxidase-Modified Metal-Organic Framework for Starving-Enhanced Chemodynamic Therapy

Chemodynamic therapy (CDT) has been considered an emerging strategy for cancer treatment. However, the tumor microenvironment (TME) with slight acidity and restricted H₂O₂ limits the efficacy of CDT. Here, we report a Hf-Mn-TCPP (Hf = hafnium; Mn-TCPP = 5, 10, 15, 20-tetrakis (4-carboxyphenyl) porphyrinato-manganese (II) chloride) loaded with glucose oxidase (GOx) to realize starving-enhanced CDT. GOx consumes glucose to produce H₂O₂ and gluconic acid. Gluconic acid increases the acidity of TME and subsequently provides favorable conditions for the Fenton-like reaction based on Hf-Mn-TCPP. The results indicate that GOx-modified Hf-Mn-TCPP provided a great therapeutic effect in starvation-enhanced CDT in vitro and in vivo.

Self-Driven Electron Transfer Biomimetic Enzymatic Catalysis of Bismuth-Doped PCN-222 MOF for Rapid Therapy of Bacteria-Infected Wounds

In this work, a biomimetic nanozyme catalyst with rapid and efficient self-bacteria-killing and wound-healing performances was synthesized. Through an in situ reduction reaction, a PCN-222 metal organic framework (MOF) was doped with bismuth nanoparticles (Bi NPs) to form Bi-PCN-222, an interfacial Schottky heterojunction biomimetic nanozyme catalyst, which can kill 99.9% of Staphylococcus aureus (S. aureus). The underlying mechanism was that Bi NP doping can endow Bi-PCN-222 MOF with self-driven charge transfer through the Schottky interface and the capability of oxidase-like and peroxidase-like activity, because a large number of free electrons can be captured by surrounding oxygen species to produce radical oxygen species (ROS). Furthermore, once bacteria contact Bi-PCN-222 in a physiological environment, its appropriate redox potential can trigger electron transfer through the electron transport pathway in bacterial membranes and then the interior of the bacteria, which disturbs the bacterial respiration process and subsequent metabolism. Additionally, Bi-PCN-222 can also accelerate tissue regeneration by upregulating fibroblast proliferation and angiogenesis genes (bFGF, VEGF, and HIF-1α), thereby promoting wound healing. This biomimetic enzyme-catalyzed strategy will bring enlightenment to the design of self-bacterial agents for efficient disinfection and tissue reconstruction simultaneously.

Trend in biodegradable porous nanomaterials for anticancer drug delivery

In recent years, biodegradable nanomaterials have exhibited remarkable promise for drug administration to tumors due to their high drug-loading capacity, biocompatibility, biodegradability, and clearance. This review will discuss and summarize the trends in utilizing biodegradable nanomaterials for anticancer drug delivery, including biodegradable periodic mesoporous organosilicas (BPMOs) and metal-organic frameworks (MOFs). The distinct structure and features of BPMOs and MOFs will be initially evaluated, as well as their use as delivery vehicles for anticancer drug delivery applications. Then, the themes for the development of each material will be utilized to illustrate their drug delivery performance. Finally, the current obstacles and potential for future development as efficient drug delivery systems will be thoroughly reviewed. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Prospects for hypoxia-based drug delivery platforms for the elimination of advanced metastatic tumors: From 3D modeling to clinical concepts

Hypoxia is a unique characteristic of the solid tumor microenvironment. Hypoxia contributes to multi-drug resistance, metastasis and cancer relapse through numerous molecular pathways, but at the same time provides an opportunity for the development of novel drugs or modalities specifically targeting hypoxic tumor regions. Given the high significance of tumor hypoxia in therapeutic results, we here discuss a variety of hypoxia-adopted strategies, and their potential and utility in the treatment of deep-seated hypoxic tumor cells. We discuss the merits and demerits of these approaches, as well as their combination with other approaches such as photodynamic therapy. We also survey the currently available 3D hypoxia modeling systems, in particular organoid-based microfluidics. Finally, we discuss the potential and the current status of preclinical tumor hypoxia approaches in clinical trials for advanced cancer. We believe that multi-modal imaging and therapeutic hypoxia adopted drug delivery platforms could provide better efficacy and safety profiles, and more importantly personalized therapy. Determining the hypoxia status of tumors could offer a second chance for the clinical translation of hypoxia-based agents, such as hypoxia activated prodrugs (HAPs) from bench to bedside.

Endo/exo-genous dual-stimuli responsive gold nanotetrapod-based nanoprobe for magnetic resonance imaging and enhanced multimodal therapeutics by amplifying·OH generation

Tumor microenvironment (TME) responsive chemodynamic therapy (CDT) can produce high-toxic hydroxyl radicals (·OH) to kill cancer cells, but the limited concentration of endogenous hydrogen peroxide (H₂O₂) seriously restricted its application. Herein, using endo/exo-genous dual-stimuli, a novel nanoprobe with enhanced ·OH generation was developed for magnetic resonance (MR) imaging and multimodal therapeutics, in which gold nanotetrapod (AuNTP) with photothermal therapy (PTT) performance was coated with mesoporous silica (mSiO₂) and loaded with cisplatin (CDDP), then a thin layer of manganese dioxide (MnO₂) was deposited to construct AuNTP@mSiO₂@CDDP@MnO₂ nanoprobes. In TME, endogenous H₂O₂, CDDP-triggered self-supplying H₂O₂ produced via cascade reaction and the exogenous photothermal effect of AuNTPs together enhanced the ·OH generation of Mn²⁺ induced by glutathione (GSH) responsive degradation of MnO₂. The prepared AuNTP@mSiO₂@CDDP@MnO₂ nanoprobes possessed perfect core@shell structure, good biocompatibility and GSH-dependent MR performance, in which the relaxation rates increased from 0.717 mM^-1·s^-1 to 8.12 mM^-1·s^-1. Under the multimodal therapeutics of CDT/PTT/chemotherapy, the developed AuNTP@mSiO₂@CDDP@MnO₂ nanoprobes demonstrated good antitumor efficacy. Our work provided a promising strategy for constructing TME-responsive nanoprobes with endo/exo-genous stimuli, achieving enhanced visualized theranostics of tumors. STATEMENT OF SIGNIFICANCE: Tumor microenvironment (TME) responsive chemodynamic therapy (CDT) can produce high-toxic hydroxyl radicals (·OH) to kill cancer cells, but the limited concentration of endogenous hydrogen peroxide (H₂O₂) seriously restricted its application. Using endo/exo-genous dual-stimuli, AuNTP@mSiO₂@CDDP@MnO₂ (AMCM) nanoprobe was constructed, in which endogenous H₂O₂, CDDP-triggered self-supplying H₂O₂ and the exogenous photothermal effect of AuNTPs together enhanced the ·OH generation. Under the multimodal therapeutics of CDT/PTT/chemotherapy, the developed AuNTP@mSiO₂@CDDP@MnO₂ nanoprobe demonstrated good antitumor efficacy, and provided a promising strategy for constructing TME-responsive nanoprobes with endo/exo-genous stimuli, achieving enhanced CDT of tumors.

Recent Advances in Metal-Organic Frameworks for Applications in Magnetic Resonance Imaging

Diagnostics is an important part of medical practice. The information required for diagnosis is typically collected by performing diagnostic tests, some of which include imaging. Magnetic resonance imaging (MRI) is one of the most widely used and effective imaging techniques. To improve the sensitivity and specificity of MRI, contrast agents are used. In this review, the usage of metal-organic frameworks (MOFs) and composite materials based on them as contrast agents for MRI is discussed. MOFs are crystalline porous coordination polymers. Due to their huge design variety and high density of metal ions, they have been studied as a highly promising class of materials for developing MRI contrast agents. This review highlights the most important studies and focuses on the progress of the field over the last five years. The materials are classified based on their design and structural properties into three groups: MRI-active MOFs, composite materials based on MOFs, and MRI-active compounds loaded in MOFs. Moreover, an overview of MOF-based materials for heteronuclear MRI including 129Xe and 19F MRI is given.

Biodegradable Metal-Organic-Frameworks-Mediated Protein Delivery Enables Intracellular Cascade Biocatalysis and Pyroptosis In Vivo

Pyroptosis is a new type of regulated cell death that is of great interest for developing new strategies for treating cancers. This potential is however greatly limited by the low efficiency and selectivity of current strategies to regulate cancer cell pyroptosis. Herein, we report biodegradable metal-organic frameworks (MOFs) for intracellular delivery of glucose oxidase (GOx) that promotes cascade biocatalysis inside cells and selectively induces cancer cell pyroptosis. We show that the self-assembly of Cu²⁺ and 4,4'-azobisbenzoic acid along with GOx affords protein-encapsulated GOx@Cu MOF that efficiently delivers GOx into cells. In addition, the tumor-cell-overexpressed NAD(P)H quinone dehydrogenase 1 (NQO1) can trigger the reduction of 4,4'-azobisbenzoic acid and the degradation of GOx@Cu MOF, releasing GOx to catalyze glucose oxidation and produce excessive hydrogen peroxide (H₂O₂) intracellularly. Furthermore, released Cu²⁺ from Cu MOF could be reduced to Cu⁺ by intracellular glutathione (GSH), promoting Fenton-like reaction with H₂O₂ to continuously generate a hydroxyl radical that induces cancer cell pyroptosis and prohibits tumor cell growth. We anticipate the strategy of harnessing biodegradable MOFs for protein delivery, and intracellular biocatalysis provides a powerful approach to regulate tumor cell pyroptosis for advanced therapeutic development.

Pan-cancer analysis of cuproptosis regulation patterns and identification of mTOR-target responder in clear cell renal cell carcinoma

BACKGROUND

The mechanism of cuproptosis, a novel copper-induced cell death by regulating tricarboxylic acid cycle (TCA)-related genes, has been reported to regulate oxidative phosphorylation system (OXPHOS) in cancers and can be regarded as potential therapeutic strategies in cancer; however, the characteristics of cuproptosis in pan-cancer have not been elucidated.

METHODS

The multi-omics data of The Cancer Genome Atlas were used to evaluate the cuproptosis-associated characteristics across 32 tumor types. A cuproptosis enrichment score (CEScore) was established using a single sample gene enrichment analysis (ssGSEA) in pan-cancer. Spearman correlation analysis was used to identify pathway most associated with CEScore. Lasso-Cox regression was used to screen prognostic genes associated with OXPHOS and further construct a cuproptosis-related prognostic model in clear cell renal cell carcinoma (ccRCC).

RESULTS

We revealed that most cuproptosis-related genes (CRGs) were differentially expressed between tumors and normal tissues, and somatic copy number alterations contributed to their aberrant expression. We established a CEScore index to indicate cuproptosis status which was associated with prognosis in most cancers. The CEScore was negatively correlated with OXPHOS and significantly featured prognosis in ccRCC. The ccRCC patients with high-risk scores show worse survival outcomes and bad clinical benefits of Everolimus (mTOR inhibitor).

CONCLUSIONS

Our findings indicate the importance of abnormal CRGs expression in cancers. In addition, identified several prognostic CRGs as potential markers for prognostic distinction and drug response in the specific tumor. These results accelerate the understanding of copper-induced death in tumor progression and provide cuproptosis-associated novel therapeutic strategies.

Engineering mitochondrial uncoupler synergistic photodynamic nanoplatform to harness immunostimulatory pro-death autophagy/mitophagy

Generally, autophagy/mitophagy, as a highly conserved lysosomal-based catabolic pathway, compromises the photodynamic therapy (PDT) efficiency by increasing the adaptation of tumor cells toward reactive oxygen species (ROS)-triggered protein damages and mitochondrial destruction. On the other hand, excessively activated autophagy/mitophagy cascades can provoke autophagic cell death and promote the endogenous antigens release of dying cells, thus playing a vital role in initiating the antitumor immune responses. To harness the exquisite immunomodulating effect of pro-death autophagy/mitophagy, we rationally constructed a MnO₂ shell-coated multifunctional porphyrinic metal-organic framework (MOF) to load carbonyl cyanide 3-chlorophenylhydrazone (CCCP). The wrapped MnO₂ shell could not only prevent premature release of CCCP during blood circulation but also conquer tumor hypoxia by catalyzing the decomposition of intratumoral H₂O₂. After entering tumor cells, the MnO₂ shell could scavenge over-expressed glutathione (GSH), resulting in burst CCCP release and GSH-depletion/O₂-generation enhanced PDT. More importantly, the released CCCP acts as a mitochondrial uncoupler can elicit mitochondrial depolarization and mitophagy, which could significantly boost the autophagy/mitophagy levels generated during PDT and consequently convert the pro-survival autophagy/mitophagy to pro-death, leading tumor cells to autophagic and immunogenic cell death. In vivo results reveal that the CCCP synergistic PDT could induce excessive immunostimulatory autophagy/mitophagy associated with T-cell responses and immunological memory, leading to complete ablation of primary tumors and prevention of tumor recurrence and lung metastasis. The effectiveness of this strategy may highlight the pro-death role and immunomodulating effect of autophagy/mitophagy in cancer therapy, providing a novel yet versatile avenue to enhance the efficacy of cancer treatments.

An Enzyme-Engineered Nonporous Copper(I) Coordination Polymer Nanoplatform for Cuproptosis-Based Synergistic Cancer Therapy

Cuproptosis, a newly identified form of regulated cell death that is copper-dependent, offers great opportunities for exploring the use of copper-based nanomaterials inducing cuproptosis for cancer treatment. Here, a glucose oxidase (GOx)-engineered nonporous copper(I) 1,2,4-triazolate ([Cu(tz)]) coordination polymer (CP) nanoplatform, denoted as GOx@[Cu(tz)], for starvation-augmented cuproptosis and photodynamic synergistic therapy is developed. Importantly, the catalytic activity of GOx is shielded in the nonporous scaffold but can be "turned on" for efficient glucose depletion only upon glutathione (GSH) stimulation in cancer cells, thereby proceeding cancer starvation therapy. The depletion of glucose and GSH sensitizes cancer cells to the GOx@[Cu(tz)]-mediated cuproptosis, producing aggregation of lipoylated mitochondrial proteins, the target of copper-induced toxicity. The increased intracellular hydrogen peroxide (H₂ O₂ ) levels, due to the oxidation of glucose, activates the type I photodynamic therapy (PDT) efficacy of GOx@[Cu(tz)]. The in vivo experimental results indicate that GOx@[Cu(tz)] produces negligible systemic toxicity and inhibits tumor growth by 92.4% in athymic mice bearing 5637 bladder tumors. This is thought to be the first report of a cupreous nanomaterial capable of inducing cuproptosis and cuproptosis-based synergistic therapy in bladder cancer, which should invigorate studies pursuing rational design of efficacious cancer therapy strategies based on cuproptosis.