Endogenous Copper for Nanocatalytic Oxidative Damage and Self-Protection Pathway Breakage of Cancer

Current progress in the regulation of endogenous molecules for enhanced chemodynamic therapy

Chemodynamic therapy (CDT) is a potential cancer treatment strategy, which relies on Fenton chemistry to transform hydrogen peroxide (H2O2) into highly cytotoxic reactive oxygen species (ROS) for tumor growth suppression. Although overproduced H2O2 in cancerous tissues makes CDT a feasible and specific tumor therapeutic modality, the treatment outcomes of traditional chemodynamic agents still fall short of expectations. Reprogramming cellular metabolism is one of the hallmarks of tumors, which not only supports unrestricted proliferative demands in cancer cells, but also mediates the resistance of tumor cells against many antitumor modalities. Recent discoveries have revealed that various cellular metabolites including H2O2, iron, lactate, glutathione, and lipids have distinct effects on CDT efficiency. In this perspective, we intend to provide a comprehensive summary of how different endogenous molecules impact Fenton chemistry for a deep understanding of mechanisms underlying endogenous regulation-enhanced CDT. Moreover, we point out the current challenges and offer our outlook on the future research directions in this field. We anticipate that exploring CDT through manipulating metabolism will yield significant advancements in tumor treatment.

Cellular Trojan Horse initiates bimetallic Fe-Cu MOF-mediated synergistic cuproptosis and ferroptosis against malignancies

Disruptions in metal balance can trigger a synergistic interplay of cuproptosis and ferroptosis, offering promising solutions to enduring challenges in oncology. Here, we have engineered a Cellular Trojan Horse, named MetaCell, which uses live neutrophils to stably internalize thermosensitive liposomal bimetallic Fe-Cu MOFs (Lip@Fe-Cu-MOFs). MetaCell can instigate cuproptosis and ferroptosis, thereby enhancing treatment efficacy. Mirroring the characteristics of neutrophils, MetaCell can evade the immune system and not only infiltrate tumors but also respond to inflammation by releasing therapeutic components, thereby surmounting traditional treatment barriers. Notably, Lip@Fe-Cu-MOFs demonstrate notable photothermal effects, inciting a targeted release of Fe-Cu-MOFs within cancer cells and amplifying the synergistic action of cuproptosis and ferroptosis. MetaCell has demonstrated promising treatment outcomes in tumor-bearing mice, effectively eliminating solid tumors and forestalling recurrence, leading to extended survival. This research provides great insights into the complex interplay between copper and iron homeostasis in malignancies, potentially paving the way for innovative approaches in cancer treatment.

A Biodegradable Nanosuspension Locally Used for Inhibiting Postoperative Recurrence and Brain Metastasis of Breast Cancer

Addressing the urgent need to prevent breast cancer postoperative recurrence and brain metastasis, Fe-metal organic framework (MOF)-coated hollow mesoporous organosilica nanoparticles (HMON) with tumor microenvironment dual-responsive degradability were prepared to encapsulate doxorubicin (DOX), formulating a tissue-adhesive nanosuspension for perioperative topical medication. This nanosuspension can not only retain the sustainably released drug in the postoperative residual tumor sites but also enhance the intracellular oxidative stress of tumors for remarkable tumor ferroptosis. Interestingly, the nanosuspension can act as an immune amplifier, which could not only stimulate DC cells to secrete chemokines for T cell recruitment but also elevate antigen exposure to facilitate the antigen presentation in lymph nodes. Thus, this nanosuspension could significantly activate antitumor immune responses in both in situ tumors and metastatic encephaloma for enhanced immunotherapy. In conjunction with the clinical PD-1 antibody, the locally administered nanosuspension could achieve an advanced therapeutic outcome for inhibiting postoperative recurrence and metastasis.

Silicon-containing nanomedicine and biomaterials: materials chemistry, multi-dimensional design, and biomedical application

The invention of silica-based bioactive glass in the late 1960s has sparked significant interest in exploring a wide range of silicon-containing biomaterials from the macroscale to the nanoscale. Over the past few decades, these biomaterials have been extensively explored for their potential in diverse biomedical applications, considering their remarkable bioactivity, excellent biocompatibility, facile surface functionalization, controllable synthesis, etc. However, to expedite the clinical translation and the unexpected utilization of silicon-composed nanomedicine and biomaterials, it is highly desirable to achieve a thorough comprehension of their characteristics and biological effects from an overall perspective. In this review, we provide a comprehensive discussion on the state-of-the-art progress of silicon-composed biomaterials, including their classification, characteristics, fabrication methods, and versatile biomedical applications. Additionally, we highlight the multi-dimensional design of both pure and hybrid silicon-composed nanomedicine and biomaterials and their intrinsic biological effects and interactions with biological systems. Their extensive biomedical applications span from drug delivery and bioimaging to therapeutic interventions and regenerative medicine, showcasing the significance of their rational design and fabrication to meet specific requirements and optimize their theranostic performance. Additionally, we offer insights into the future prospects and potential challenges regarding silicon-composed nanomedicine and biomaterials. By shedding light on these exciting research advances, we aspire to foster further progress in the biomedical field and drive the development of innovative silicon-composed nanomedicine and biomaterials with transformative applications in biomedicine.

Catechol-Isolated Atomically Dispersed Nanocatalysts for Self-Motivated Cocatalytic Tumor Therapy

Nanocatalytic tumor therapy based on Fenton nanocatalysts has attracted considerable attention because of its therapeutic specificity, enhanced outcomes, and high biocompatibility. Nevertheless, the rate-determining step in Fenton chemistry, which involves the transition of a high-valence metallic center (FeIII ) to a Fenton-active low-valence metallic center (FeII ), has hindered advances in nanocatalyst-based therapeutics. In this study, we constructed mesoporous single iron atomic nanocatalysts (mSAFe NCs) by employing catechols from dopamine to coordinate and isolate single iron atoms. The catechols also serve as reductive ligands, generating a field-effect-based cocatalytic system that instantly reduces FeIII species to FeII species within the mSAFe NCs. This self-motivated cocatalytic strategy enabled by mSAFe NCs accelerates the kinetics of the Fenton catalytic reaction, resulting in remarkable performance for nanocatalytic tumor therapy both in vitro and in vivo.

MOFs Modulate Copper Trafficking in Tumor Cells for Bioorthogonal Therapy

In situ drug synthesis using the copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction has attracted considerable attention in tumor therapy because of its satisfactory effectiveness and reduced side-effects. However, the exogenous addition of copper catalysts can cause cytotoxicity and has hampered biomedical applications in vivo. Here, we design and synthesize a metal-organic framework (MOF) to mimic copper chaperone, which can selectively modulate copper trafficking for bioorthogonal synthesis with no need of exogenous addition of copper catalysts. Like copper chaperones, the prepared ZIF-8 copper chaperone mimics specifically bind copper ions through the formation of coordination bonds. Moreover, the copper is unloaded under the acidic environment due to the dissipation of the coordination interactions between metal ions and ligands. In this way, the cancer cell-targeted copper chaperone mimics can selectively transport copper ions into cells. Regulation of intracellular copper trafficking may inspire constructing bioorthogonal catalysis system with reduced metal cytotoxicity in live cells.

A novel CT-responsive hydrogel for the construction of an organ simulation phantom for the repeatability and stability study of radiomic features

Radiomic features have demonstrated reliable outcomes in tumor grading and detecting precancerous lesions in medical imaging analysis. However, the repeatability and stability of these features have faced criticism. In this study, we aim to enhance the repeatability and stability of radiomic features by introducing a novel CT-responsive hydrogel material. The newly developed CT-responsive hydrogel, mineralized by in situ metal ions, exhibits exceptional repeatability, stability, and uniformity. Moreover, by adjusting the concentration of metal ions, it achieves remarkable CT similarity comparable to that of human organs on CT scans. To create a phantom, the hydrogel was molded into a universal model, displaying controllable CT values ranging from 53 HU to 58 HU, akin to human liver tissue. Subsequently, 1218 radiomic features were extracted from the CT-responsive hydrogel organ simulation phantom. Impressively, 85-97.2% of the extracted features exhibited good repeatability and stability during coefficient of variability analysis. This finding emphasizes the potential of CT-responsive hydrogel in consistently extracting the same features, providing a novel approach to address the issue of repeatability in radiomic features.

A Strategy of Fenton Reaction Cycloacceleration for High-Performance Ferroptosis Therapy Initiated by Tumor Microenvironment Remodeling

The emerging tumor ferroptosis therapy confronts impediments of the tumor microenvironment (TME) with weak intrinsic acidity, inadequate endogenous H2 O2 , and a powerful intracellular redox balance system that eliminates toxic reactive oxygen species (ROS). Herein, a strategy of Fenton reaction cycloacceleration initiated by remodeling the TME for magnetic resonance imaging (MRI)-guided high-performance ferroptosis therapy of tumors is proposed. The synthesized nanocomplex exhibits enhanced accumulation at carbonic anhydrase IX (CAIX)-positive tumors based on the CAIX-mediated active targeting, and increased acidification via the inhibition of CAIX by 4-(2-aminoethyl) benzene sulfonamide (ABS) (remodeling TME). This accumulated H+ and abundant glutathione in TME synergistically trigger biodegradation of the nanocomplex to release the loaded cuprous oxide nanodots (CON), β-lapachon (LAP), Fe3+ , and gallic acid-ferric ions coordination networks (GF). The Fenton and Fenton-like reactions are cycloaccelerated via the catalytic loop of Fe-Cu, and the LAP-triggered and nicotinamide adenine dinucleotide phosphate quinone oxidoreductase1-mediated redox cycle, generating robust ROS and plenitudinous lipid peroxides accumulation for ferroptosis of tumor cells. The detached GF network has improved relaxivities in response to the TME. Therefore, the strategy of Fenton reaction cycloacceleration initiated by remodeling the TME is promising for MRI-guided high-performance ferroptosis therapy of tumors.

Ceria Nanoparticles as Copper Chaperones that Activate SOD1 for Synergistic Antioxidant Therapy to Treat Ischemic Vascular Diseases

All exogenous nanomaterials undergo rapid biotransformation once injected into the body and fall short of executing the intended purpose. Here, it is reported that copper-deposited ceria nanoparticles (CuCe NPs) exhibit enhanced antioxidant effects over pristine ceria nanoparticles, as the released copper buffers the depletion of glutathione while providing the bioavailable copper as a cofactor for the antioxidant enzyme, superoxide dismutase 1. The upregulated intracellular antioxidants along with the ceria nanoparticles synergistically scavenge reactive oxygen species and promote anti-inflammation and M2 polarization of macrophages by modulating signal transducer and activator of transcription 1 and 6 (STAT1 and STAT6). The therapeutic effect of CuCe NPs is demonstrated in ischemic vascular diseases (i.e., murine models of hindlimb ischemia and myocardial infarction) in which the copper-deposition affords increased perfusion and alleviation in tissue damage. The results provide rationale that metal oxide nanomaterials can be designed in a way to induce the upregulation of specific biological factors for optimal therapeutic performance.

Nanosized drug delivery strategies in osteosarcoma chemotherapy

Despite recent developments worldwide in the therapeutic care of osteosarcoma (OS), the ongoing challenges in overcoming limitations and side effects of chemotherapy drugs warrant new strategies to improve overall patient survival. Spurred by rapid progress in biomedicine, nanobiotechnology, and materials chemistry, chemotherapeutic drug delivery in treatment of OS has become possible in recent years. Here, we review recent advances in the design of drug delivery system, especially for chemotherapeutic drugs in OS, and discuss the relative merits in trials along with future therapeutic options. These advances may pave the way for novel therapies requisite for patients with OS.

Precisely designed Fex (x = 1-2) cluster nanocatalysts for effective nanocatalytic tumor therapy

Atomically dispersed metal clusters are considered as promising nanocatalysts due to their excellent physicochemical properties. Here, we report a novel strategy for precisely designing Fe_x (x = 1-2) cluster nanocatalysts (Fe₁-N-C and Fe₂-N-C) with dual catalytic activity, which can catalyze H₂O₂ into reactive oxygen species (ROS) and oxidize glutathione (GSH) into glutathione disulfide simultaneously. The adsorption energies of Fe-N sites in Fe₂-N-C for GSH and H₂O₂ intermediates were well controlled due to the orbital modulation of adjacent Fe sites, contributing to the higher dual catalytic activity compared to Fe₁-N-C. Additionally, tamoxifen (TAM) was loaded into Fe₂-N-C (Fe₂@TDF NEs) to down-regulate the intracellular pH for higher Fenton-like catalytic efficiency and ROS production. The generated ROS could induce apoptosis and lipid peroxidation, triggering ferroptosis. Meanwhile, upregulation of ROS and lipid peroxidation, along with GSH depletion and GPX4 downregulation could promote the apoptosis and ferroptosis of tumor cells. In addition, the lactic acid accumulation effect of TAM and the high photothermal conversion ability of Fe₂@TDF NEs could further enhance the catalytic activity to achieve synergistic antitumor effects. As a result, this work highlights the critical role of adjacent metal sites at the atomic-level and provides a rational guidance for the design and application of nanocatalytic antitumor systems.

Boosting Endogenous Copper(I) for Biologically Safe and Efficient Bioorthogonal Catalysis via Self-Adaptive Metal-Organic Frameworks

As one of the most typical bioorthogonal reactions, the Cu(I)-catalyzed azide-alkyne 1,3-cycloaddition (CuAAC) reaction has received worldwide attention in intracellular transformation of prodrugs due to its high efficiency and selectivity. However, the exogenous Cu catalysts may disturb Cu homeostasis and cause side effects to normal tissues. What is more, the intratumoral Cu(I) is insufficient to efficiently catalyze the intracellular CuAAC reaction due to oncogene-induced labile Cu(I) deficiency. Herein, in order to boost the endogenous Cu(I) level for intracellular drug synthesis through the bioorthogonal reaction, a self-adaptive bioorthogonal catalysis system was constructed by encapsulating prodrugs and sodium ascorbate within adenosine triphosphate aptamer-functionalized metal-organic framework nanoparticles. The system presents specificity to tumor cells and does not require exogenous Cu catalysts, thereby leading to high anti-tumor efficacy and minimal side effects both in vitro and in vivo. This work will open up a new opportunity for developing biosafe and high-performance bioorthogonal catalysis systems.

Brain-Targeted HFn-Cu-REGO Nanoplatform for Site-Specific Delivery and Manipulation of Autophagy and Cuproptosis in Glioblastoma

Durable glioblastoma multiforme (GBM) management requires long-term chemotherapy after surgery to eliminate remaining cancerous tissues. Among chemotherapeutics, temozolomide is considered as the first-line drug for GBM therapy, but the treatment outcome is not satisfactory. Notably, regorafenib, an oral multi-kinase inhibitor, has been reported to exert a markedly superior effect on GBM suppression compared with temozolomide. However, poor site-specific delivery and bioavailability significantly restrict the efficient permeability of regorafenib to brain lesions and compromise its treatment efficacy. Therefore, human H-ferritin (HFn), regorafenib, and Cu²⁺ are rationally designed as a brain-targeted nanoplatform (HFn-Cu-REGO NPs), fulfilling the task of site-specific delivery and manipulating autophagy and cuproptosis against GBM. Herein, HFn affords a preferential accumulation capacity to GBM due to transferrin receptor 1 (TfR1)-mediated active targeting and pH-responsive delivery behavior. Moreover, regorafenib can inhibit autophagosome-lysosome fusion, resulting in lethal autophagy arrest in GBM cells. Furthermore, Cu²⁺ not only facilitates the encapsulation of regorafenib to HFn through coordination interaction but also disturbs copper homeostasis for triggering cuproptosis, resulting in a synergistical effect with regorafenib-mediated lethal autophagy arrest against GBM. Therefore, this work may broaden the clinical application scope of Cu²⁺ and regorafenib in GBM treatment via modulating autophagy and cuproptosis.

Macromolecular NO-Donor Micelles for Targeted and Augmented Chemotherapy against Prostate Cancer

Mitoxantrone (MTO) is clinically utilized for treating hormone-refractory prostate cancer (PCa), however, the therapeutic outcome is far from optimal due to the lack of proper drug carrier as well as the inherent MTO detoxification mechanisms of DNA lesion repair and anti-oxidation. Herein, a bombesin-installed nanoplatform combining the chemotherapeutic MTO and the chemotherapeutic sensitizer of nitric oxide (NO) is developed based on MTO-loaded macromolecular NO-donor-containing polymeric micelles (BN-NM_MTO ) for targeted NO-sensitized chemotherapy against PCa. BN-NM_MTO actively target and accumulates in PCa sites and are internalized into the tumor cells. The macromolecular NO-donor of BN-NM_MTO undergoes a reductive reaction to unleash NO upon intracellular glutathione (GSH), accompanying by micelle swelling and MTO release. The targeted intracellular MTO release induces DNA lesion and reactive oxygen species (ROS) generation in tumor cells without damage to the normal cells, and MTO's cytotoxicity is further augmented by NO release via the inhibition of both DNA repair and anti-oxidation pathways as compared with traditional MTO therapies.

Dual-Cascade Responsive Nanoparticles Enhance Pancreatic Cancer Therapy by Eliminating Tumor-Resident Intracellular Bacteria

The limited drug penetration and robust bacteria-mediated drug inactivation in pancreatic cancer result in the failure of chemotherapy. To fight against these issues, a dual-cascade responsive nanoparticle (sNP@G/IR) that can sequentially trigger deep penetration, killing of intratumor bacteria, and controlled release of chemo-drug, is reported. sNP@G/IR consists of a hyaluronic acid (HA) shell and glutathione (GSH)-responsive polymer-core (NP@G/IR), that encapsulates gemcitabine (Gem) and photothermal agent (IR1048). The polymer core, as an antibiotic alternative, is tailored to exert optimal antibacterial activity and selectivity. sNP@G/IR actively homes in on the tumor due to the CD44 targeting of the HA shell, which is subsequently degraded by the hyaluronidase in the extracellular matrix. The resultant NP@G/IR in decreased size and reversed charge facilitates deep tumor penetration. After cellular endocytosis, the exposed guanidine on NP@G/IR kills intracellular bacteria through disrupting cell membranes. Intracellular GSH further triggers the controlled release of the cargo. Thus, the protected Gem eventually induces cell apoptosis. Under laser irradiation, the hyperthermia of IR1048 helps further elimination of tumors and bacteria. Moreover, sNP@G/IR activates immune response, thereby reinforcing anticancer capacity. Therefore, this dual-cascade responsive sNP@G/IR eliminates tumor-resident intracellular bacteria and augments drug delivery efficacy, providing a new avenue for improving cancer therapy.

Metal and Metal Oxide Nanomaterials for Fighting Planktonic Bacteria and Biofilms: A Review Emphasizing on Mechanistic Aspects

The misuse and mismanagement of antibiotics have made the treatment of bacterial infections a challenge. This challenge is magnified when bacteria form biofilms, which can increase bacterial resistance up to 1000 times. It is desirable to develop anti-infective materials with antibacterial activity and no resistance to drugs. With the rapid development of nanotechnology, anti-infective strategies based on metal and metal oxide nanomaterials have been widely used in antibacterial and antibiofilm treatments. Here, this review expounds on the state-of-the-art applications of metal and metal oxide nanomaterials in bacterial infective diseases. A specific attention is given to the antibacterial mechanisms of metal and metal oxide nanomaterials, including disrupting cell membranes, damaging proteins, and nucleic acid. Moreover, a practical antibiofilm mechanism employing these metal and metal oxide nanomaterials is also introduced based on the composition of biofilm, including extracellular polymeric substance, quorum sensing, and bacteria. Finally, current challenges and future perspectives of metal and metal oxide nanomaterials in the anti-infective field are presented to facilitate their development and use.

Photo-enhanced upcycling H2O2 into hydroxyl radicals by IR780-embedded Fe3O4@MIL-100 for intense nanocatalytic tumor therapy

Reactive oxygen species (ROS)-based nanocatalytic tumor therapy is alluring owing to the capability to generate highly cytotoxic ∙OH radicals from tumoral H2O2. However, the antitumor efficacy is highly dependent on the radical generation efficiency and challenged by the high levels of antioxidative glutathione (GSH) in cancer cells. Herein, we report an IR-780 decorated, GSH-depleting Fe3O4@MIL-100 (IFM) nanocomposite for photo-enhanced tumor catalytic therapy by extensive production of ∙OH, which is realized by an integration of excellent peroxidase-like activity of IFM, selective upregulation of tumoral H2O2 by β-lapachone, and localized hyperthermia by near infrared light irradiation. IFM shows potentiated antiproliferative effect in 4T1 cancer cells by ∙OH overproduction and glutathione scavenging, inducing intracellular redox dyshomeostasis and cell death by concurrent apoptosis and ferroptosis. In vivo antitumor investigation further demonstrates photoacoustic and fluorescence imaging-guided combinational therapy with a tumor inhibition rate of 96.4%. This study provides a strategy of photo-enhanced nanocatalytic tumor therapy by tumor-specific H2O2 amplification and hyperthermia.

Copper(II) based low molecular weight collagen fragments-chlorin e6 nanoparticles synergize anti-cancer and anti-bacteria photodynamic therapy

Copper-based photosensitizer nanoparticle has high potential clinic translation potency for its extensive physiological effects such as anti-cancer progression, anti-bacteria and accelerate tissue regeneration. However, copper excess or improper coordination can induce toxicity or reduce drug efficacy. To get proper copper-photosensitizer complex nanoparticle, a portion of chlorin e6 covalently conjugated with low molecular weight fish collagen fragments-collage tripeptides (CTPs), and Cu²⁺ subsequently triggers CTP-Ce6 conjugates assemble to Cu(II) based CTP-Ce6 nanosphere(CCeC-Ns). CCeC-Ns are 10-20 nm nanoparticles. CCeC-Ns quenched Ce6 fluorescence in aqueous solution and improved longer wavelength light absorbance. It exhibited dramatically higher cellular uptake rates and much more anticancer potency than those of free Ce6 under 660 nm irradiation without obvious dark toxicity in vitro. CCeC-Ns have longer retention time and higher penetrating rate than free Ce6 in tumor spheroid model. CCeC-Ns displayed extremely higher anti-bacterial potency than free Ce6 and sustainable efficacy. It provides a more potent and safer nanodrug for cancer and infection treatment and an idea for highly efficient metal-photosensitizers complexes design.

A core-shell liquid metal-Cu nanoparticle with glutathione consumption via an in situ replacement strategy for tumor combination treatment of chemodynamic, microwave dynamic and microwave thermal therapy

The presence of high content glutathione (GSH) provides an effective "protective shield" for tumor cells, which undoubtedly is a huge impediment to reactive oxygen species (ROS)-based treatment. Fortunately, divalent copper (Cu²⁺) can not only consume GSH, destroying the protection mechanism of GSH, but also can be reduced to Cu⁺ with excellent Fenton-like reaction activity. Hence, capitalizing on the properties of liquid metals, we introduced Cu with three different valances via an in situ replacement reaction. A stable core-shell liquid-metal based "Cu storage pool" was obtained. It can effectively deplete GSH within the cells, and simultaneously produce ·OH through a Fenton-like reaction, further improving the effect of chemodynamic therapy (CDT). Under microwave irradiation, it is also capable of producing a large amount of ROS to promote tumor treatment. In addition, the loading of ionic liquid endows LZC@IL nanoparticles with certain microwave heating performance, which is able to augment microwave thermal therapy (MWTT). With the combination of CDT, microwave dynamic therapy (MDT) and MWTT, LZC@IL has an excellent effect on tumor elimination. This work offers a new idea for the application of liquid metals and the combined treatment of tumors, which has potential application value.