Cu-Ferrocene-Functionalized CaO2 Nanoparticles to Enable Tumor-Specific Synergistic Therapy with GSH Depletion and Calcium Overload

UV-activated calcium peroxide system enables simultaneous organophosphorus degradation, phosphate recovery, and carbon fixation

Advanced oxidation processes are a desirable technology for treatment of contaminants of emerging concern. Nevertheless, conventional advanced oxidation of organophosphorus compounds releases inorganic phosphate, posing downstream concerns related to eutrophication. For this reason, we evaluated the ultraviolet light-activated calcium peroxide (UV/CaO2) system for effective treatment of organophosphorus compounds and concurrent capture of the mineralization products, phosphate. The degradation mechanisms, reaction kinetics, and mineralizations were assessed to determine the overall efficiency and performance of the UV/CaO2 process. Knowledge gaps related to photocatalysis in the UV/CaO2 system were not only addressed, but also leveraged to identify unique advantages for removal of organophosphorus compounds and their degradation products. Experimental results confirmed that the UV/CaO2 system effectively mineralized organophosphorus compounds and recovered inorganic phosphate; additionally, collaborative carbon fixation performance of the system reveals the potential of carbon utilization. These outcomes were facilitated by the alkaline environment generated by CaO2. The recovered solids contained most of the phosphorus and carbon from the parent compounds. Ultimately, these findings provide transformative, new insights into the development and application of advanced oxidation processes that prevent downstream concerns related to mineralization products, especially inorganic phosphorus and carbon.

An acid-activatable fluorouracil prodrug for colorectal cancer synergistic therapy

5-Fluorouracil has demonstrated certain efficiency in patients with colorectal cancer. However, significant side effects of use by injection are common. To address this issue defects, a reengineered 5'-deoxy-5-fluorocytidine (DFCR) based drug delivery system (POACa) is developed as a prominent tumor-selective nano-activator. Investigations demonstrate that the constructed nano-activator exhibits good biocompatibility and high therapeutic efficiency in mice with subcutaneous and orthotopic SW-480 colorectal tumors, as its activity is strictly dependent on the tumor-associated acid environment and thymidine phosphorylase. These strategies diminish the off-target toxicity and improve the specificity and sensitivity of human colorectal cancer cells to 5-Fu, obtaining potent efficiency by the combination of H2O2 mediated oxidative stress, calcium overload and 5-Fu-induced chemotherapy (the combination index is 0.11). Overall, the engineered nano-activator exhibits a high therapeutic index in vitro and in vivo. STATEMENT OF SIGNIFICANCE: In this study, we designed and prepared a pH-responsive polymer to synchronously deliver DFCR (5'-deoxy-5-fluorocytidine, a prodrug of 5-Fu), Ca2+ and H2O2. The constructed nano-activator was denoted as POACa. (1) To address the problem of premature leakage of cargo by physical embedding, our research modified the inactive prodrug DFCR through chemical bonding. (2) The activation of the prepared nano-activator was strictly dependent on the tumor-associated acid environment and thymidine phosphorylase, providing the drug delivery system with inherent safety. (3) A distinctly low combination index value (0.11) of CaO2 and DFCR indicated that POACa has a prominent tumor suppression effect by tumor calcium overload sensitized chemotherapy and H2O2 mediated cytotoxicity.

Hollow mesoporous calcium peroxide nanoparticles for drug-free tumor calcicoptosis therapy

Calcium ions (Ca2+) participate in the regulation of cellular apoptosis as a second messenger. Calcium overload, which refers to the abnormal elevation of intracellular Ca2+ concentration, is a factor that can lead to cell death. Here, based on the unique biological effects of Ca2+, hollow mesoporous calcium peroxide nanoparticles (HMCPN) were developed by a facile hydrolysis-precipitation method for drug-free tumor calcicoptosis therapy. The average pore size of the optimized HMCPN17 is 6.4 nm, and the surface area is 81.3 m2/g, which enables HMCPN17 with high drug loading capability. The Ca2+ release from HMCPN17 is much faster at pH 6.8 than that at pH 7.4, which can be ascribed to the acid-triggered conversion of HMCPN17 to Ca2+ and H2O2, indicating a pH-responsive decomposition behavior of HMCPN17. The high drug loading contents of doxorubicin (DOX) and/or sorafenib (SFN) indicate that HMCPN17 can be employed as a generic drug delivery system (DDS). The in vitro and in vivo results reinforce the high calcicoptosis therapeutic efficacy of tumors by our HMCPN17 without drug loading, which can be attributed to the efficient accumulation in tumors and the ability of H2O2 and Ca2+ production at acidic TME. Our HMCPN17 has broad application prospect for construction of multi-drug-loaded composite nanomaterials with diversified functions for the treatment of tumors. STATEMENT OF SIGNIFICANCE: The combination of hollow mesoporous nanomaterials and calcium peroxide nanoparticles has a wide range of applications in the synergistic treatment of tumors. In this study, hollow mesoporous calcium peroxide nanoparticles (HMCPN) were developed based on a simple hydrolysis-precipitation method for tumor calcicoptosis therapy without drug loading. The high drug loading contents of DOX and/or SFN indicate that our HMCPN can serve as a generic DDS. The experimental results demonstrated the high calcicoptosis therapeutic efficacy of HMCPN on tumors even without drug loading.

Acidity-Responsive Fe-PDA@CaCO3 Nanoparticles for Photothermal-Enhanced Calcium-Overload- and Reactive-Oxygen-Species-Mediated Tumor Therapy

Calcium-overload-mediated tumor therapy has received considerable interest in oncology. However, its efficacy has been proven to be inadequate due to insufficient calcium ion concentration at the tumor site coupled with challenges in facilitating efficient calcium uptake by tumors, leading to unsatisfactory therapeutic outcomes. In the present study, calcium carbonate nanoshell mineralized ferric polydopamine nanoparticles (Fe-PDA@CaCO3 NPs) were prepared for achieving Ca2+-overload-mediated tumor therapy. Upon entering the tumor site, the pH-responsive CaCO3 layer, acting as a "Ca2+ storage pool", rapidly degraded and released high quantities of free Ca2+ within the weakly acidic environment. The Fe-PDA core, with its excellent photothermal conversion properties, could significantly increase the temperature upon exposure to near-infrared (NIR) light irradiation, thereby activating the TRPV1 channel and leading to a large influx of released Ca2+ into the cytoplasm. Furthermore, the exposed Fe-PDA core could react with the tumor-overexpressed hydrogen peroxide (H2O2) to efficiently produce hydroxyl radicals (•OH), significantly increasing intracellular reactive oxygen species (ROS) levels and thus inhibiting the activity of the Ca2+ efflux pump, resulting in a high intracellular Ca2+ concentration. Ultimately, the increase in calcium/ROS levels could disrupt mitochondrial homeostasis and activate the apoptosis pathway. The current work presents a promising approach for tumor therapy using photothermal-enhanced calcium-overload-mediated ion interference therapy and chemodynamic therapy.

Naked mesoporous rhodium nanospheres with glutathione depletion and photothermal capabilities for tumor therapy

Pancreatic and colon cancer are malignant tumors of the digestive system that currently lack effective treatments. In cancer cells, a high level of glutathione (GSH) is indispensable to scavenge excessive reactive oxygen species (ROS) and detoxify xenobiotics, which make it a potential target for cancer therapy. GSH depletion has been proved to improve the therapeutic efficacy of photodynamic therapy. Here, we reported that naked mesoporous rhodium nanospheres (Rh MNs), prepared by soft template redox method, can act as GSH depletion agent and photothermal conversion agent to achieve synergistic therapy respectively. Different from conventional nanoagents, Rh MNs with the characteristics of easy synthesis, simple structure and multiple functions can decrease the GSH level in tumor and depict excellent photothermal ability with a high photothermal conversion efficiency (PTCE) up to 39%. Notably, multiple anti-tumor mechanisms in CT26 and BxPC-3 tumor models, include inhibited anti-apoptosis, DNA replication repair, and GSH synthesis are revealed, and the pancreatic tumor cure rate of the cooperative treatment group is 80%. Collectively, we developed Rh MNs to combine GSH depletion with photothermal therapy for cancer treatment.

Photo-Activated Oxidative Stress Amplifier: A Strategy for Targeting Glutathione Metabolism and Enhancing ROS-Mediated Therapy in Triple-Negative Breast Cancer Treatment

Amplifying oxidative stress within tumor cells can effectively inhibit the growth and metastasis of triple-negative breast cancer (TNBC). Therefore, the development of innovative nanomedicines that can effectively disrupt the redox balance represents a promising yet challenging therapeutic strategy for TNBC. In this study, an oxidative stress amplifier, denoted as PBCH, comprising PdAg mesoporous nanozyme and a CaP mineralized layer, loaded with GSH inhibitor L-buthionine sulfoximine (BSO), and further surface-modified with hyaluronic acid that can target CD44, is introduced. In the acidic tumor microenvironment, Ca2+ is initially released, thereby leading to mitochondrial dysfunction and eventually triggering apoptosis. Additionally, BSO suppresses the synthesis of intracellular reduced GSH and further amplifies the level of oxidative stress in cancer cells. Furthermore, PdAg nanozyme can be activated by near-infrared light to induce photothermal and photodynamic effects, causing a burst of ROS and simultaneously promoting cell apoptosis via provoking immunogenic cell death. The high-performance therapeutic effects of PBCH, based on the synergistic effect of aforementioned multiple oxidative damage and photothermal ablation, are validated in TNBC cells and animal models, declaring its potential as a safe and effective anti-tumor agent. The proposed approach offers new perspectives for precise and efficient treatment of TNBC.

Hyaluronic acid-based multifunctional nanoplatform for glucose deprivation-enhanced chemodynamic/photothermal synergistic cancer therapy

We present a hyaluronic acid (HA)-based nanoplatform (CMGH) integrating starvation therapy (ST), chemodynamic therapy (CDT), and photothermal therapy (PTT) for targeted cancer treatment. CMGH fabrication involved the encapsulation of glucose oxidase (GOx) within a copper-based metal-organic framework (CM) followed by surface modification with HA. CMGH exerts its antitumor effects by catalyzing glucose depletion at tumor sites, leading to tumor cell starvation and the concomitant generation of glucuronic acid and H2O2. The decreased pH and elevated H2O2 promote the Fenton-like reaction of Cu ions, leading to hydroxyl radical production. HA modification enables targeted accumulation of CMGH at tumor sites via the CD44 receptor. Under near-infrared light irradiation, CM exhibits photothermal conversion capability, enhancing the antitumor effects of CMGH. In vitro and in vivo studies demonstrate the effective inhibition of tumor growth by CMGH. This study highlights the potential of CMGH as a targeted cancer therapeutic platform.

Engineering of a double targeting nanoplatform to elevate ROS generation and DSF anticancer activity

Intracellular oxidative protection mechanisms and adverse systemic toxicity are major obstacles for the success of chemodynamic therapy (CDT)/chemotherapy (CT) synergistic therapy. To tackle the fundamental challenges of current CDT and circumvent the side effects of conventional CT, we developed a copper peroxide (CP) and disulfiram (DSF)-loaded 3-aminotriazole (3-AT) doped ZIF-8 (MAF) with partial sequence-specificity using hyaluronic acid (HA) and triphenylphosphine (TPP) in this study. Upon intravenous administration, CP@MAF-DSF@PEG-TPP@HA (CPMDTH) nanoparticles (NPs) were enriched in tumor tissues through HA-mediated endocytosis, followed by enhanced accumulation in mitochondria by the TPP target. The acidic tumor environment (TME) triggered the decomposition of MAF to release CP, DSF and 3-AT. Cu2+ and H2O2 hydrated from CP NPs produced ˙OH via a Fenton-like reaction. CAT activity inhibition and GSH consumption induced by 3-AT dramatically amplified mitochondrial oxidative stress, thereby promoting the overproduction of ˙OH. In addition, the accumulation of DSF and Cu2+ led to the formation of a cytotoxic bis(N,N-diethyldithiocarbamate) copper(II) complex (Cu(DTC)2) in situ, achieving efficient CT. CPMDTH NPs demonstrated significantly improved antitumor efficiency and excellent biosafety both in vitro and in vivo. This study offers a promising therapeutic strategy for CDT/CT synergistic oncotherapy.

Poly(ferrocenylsilane)-Based Redox-Active Artificial Organelles for Biomimetic Cascade Reactions

Artificial organelles serve as functional counterparts to natural organelles, which are primarily employed to artificially replicate, restore, or enhance cellular functions. While most artificial organelles exhibit basic functions, we diverge from this norm by utilizing poly(ferrocenylmethylethylthiocarboxypropylsilane) microcapsules (PFC MCs) to construct multifunctional artificial organelles through water/oil interfacial self-assembly. Within these PFC MCs, enzymatic cascades are induced through active molecular exchange across the membrane to mimic the functions of enzymes in mitochondria. We harness the inherent redox properties of the PFC polymer, which forms the membrane, to facilitate in-situ redox reactions similar to those supported by the inner membrane of natural mitochondria. Subsequent studies have demonstrated the interaction between PFC MCs and living cell including extended lifespans within various cell types. We anticipate that functional PFC MCs have the potential to serve as innovative platforms for organelle mimics capable of executing specific cellular functions.

Programmable Release of Chemotherapeutics from Ferrocene-Based Injectable Hydrogels Slows Melanoma Growth

Hydrogel-based injectable drug delivery systems provide temporally and spatially controlled drug release with reduced adverse effects on healthy tissues. Therefore, they represent a promising therapeutic option for unresectable solid tumor entities. In this study, a peptide-starPEG/hyaluronic acid-based physical hydrogel is modified with ferrocene to provide a programmable drug release orchestrated by matrix-drug interaction and local reactive oxygen species (ROS). The injectable ROS-responsive hydrogel (hiROSponse) exhibits adequate biocompatibility and biodegradability, which are important for clinical applications. HiROSponse is loaded with the two cytostatic drugs (hiROSponsedox/ptx) doxorubicin (dox) and paclitaxel (ptx). Dox is a hydrophilic compound and its release is mainly controlled by Fickian diffusion, while the hydrophobic interactions between ptx and ferrocene can control its release and thus be regulated by the oxidation of ferrocene to the more hydrophilic state of ferrocenium. In a syngeneic malignant melanoma-bearing mouse model, hiROSponsedox/ptx slows tumor growth without causing adverse side effects and doubles the relative survival probability. Programmable release is further demonstrated in a tumor model with a low physiological ROS level, where dox release, low dose local irradiation, and the resulting ROS-triggered ptx release lead to tumor growth inhibition and increased survival.

Gas-propelled nanomotors alleviate colitis through the regulation of intestinal immunoenvironment-hematopexis-microbiota circuits

The progression of ulcerative colitis (UC) is associated with immunologic derangement, intestinal hemorrhage, and microbiota imbalance. While traditional medications mainly focus on mitigating inflammation, it remains challenging to address multiple symptoms. Here, a versatile gas-propelled nanomotor was constructed by mild fusion of post-ultrasonic CaO2 nanospheres with Cu2O nanoblocks. The resulting CaO2-Cu2O possessed a desirable diameter (291.3 nm) and a uniform size distribution. It could be efficiently internalized by colonic epithelial cells and macrophages, scavenge intracellular reactive oxygen/nitrogen species, and alleviate immune reactions by pro-polarizing macrophages to the anti-inflammatory M2 phenotype. This nanomotor was found to penetrate through the mucus barrier and accumulate in the colitis mucosa due to the driving force of the generated oxygen bubbles. Rectal administration of CaO2-Cu2O could stanch the bleeding, repair the disrupted colonic epithelial layer, and reduce the inflammatory responses through its interaction with the genes relevant to blood coagulation, anti-oxidation, wound healing, and anti-inflammation. Impressively, it restored intestinal microbiota balance by elevating the proportions of beneficial bacteria (e.g., Odoribacter and Bifidobacterium) and decreasing the abundances of harmful bacteria (e.g., Prevotellaceae and Helicobacter). Our gas-driven CaO2-Cu2O offers a promising therapeutic platform for robust treatment of UC via the rectal route.

The H2O2 Self-Sufficient 3D Printed β-TCP Scaffolds with Synergistic Anti-Tumor Effect and Reinforced Osseointegration

Tumor recurrence and massive bone defects are two critical challenges for postoperative treatment of oral and maxillofacial tumor, posing serious threats to the health of patients. Herein, in order to eliminate residual tumor cells and promote osteogenesis simultaneously, the hydrogen peroxide (H2O2) self-sufficient TCP-PDA-CaO2-CeO2 (TPCC) scaffolds are designed by preparing CaO2 or/and CeO2 nanoparticles (NPs)/chitosan solution and modifying the NPs into polydopamine (PDA)-modified 3D printed TCP scaffolds by rotary coating method. CaO2 NPs loaded on the scaffolds can release Ca2+ and sufficient H2O2 in the acidic tumor microenvironment (TME). The generated H2O2 can further produce hydroxyl radicals (·OH) under catalysis effect by peroxidase (POD) activity of CeO2 NPs, in which the photothermal effect of the PDA coating enhances its POD catalytic effect. Overall, NPs loaded on the scaffold chemically achieve a cascade reaction of H2O2 self-sufficiency and ·OH production, while functionally achieving synergistic effects on anti-tumor and bone promotion. In vitro and in vivo studies show that the scaffolds exhibit effective osteo-inductivity, induced osteoblast differentiation and promote osseointegration. Therefore, the multifunctional composite scaffolds not only validate the concept of chemo-dynamic therapy (CDT) cascade therapy, but also provide a promising clinical strategy for postoperative treatment of oral and maxillofacial tumor.

Ultrasound-augmented enzyodynamic-Ca2+ overload synergetic tumor nanotherapy

The excessive intracellular Ca2+ can induce oxidative stress, mitochondrial damage and cell apoptosis, which has been extensively explored for tumor therapy. However, the low Ca2+ accumulation originated from Ca2+-based nanosystems substantially weakens the therapeutic effect. Herein, a functional plant polyphenol-appended enzyodynamic nanozyme system CaFe2O4@BSA-curcumin (abbreviation as CFO-CUR) has been rationally designed and engineered to achieve magnified Ca2+ accumulation process, deleterious reactive oxygen species (ROS) production, as well as mitochondrial dysfunction through enzyodynamic-Ca2+ overload synergistic effect. The exogenous Ca2+ released by CaFe2O4 nanozymes under the weakly acidic tumor microenvironment and Ca2+ efflux inhibition by curcumin boost mitochondria-dominant antineoplastic efficiency. The presence of Fe components with multivalent characteristic depletes endogenous glutathione and outputs the incremental ROS due to the oxidase-, peroxidase-, glutathione peroxidase-mimicking activities. The ROS burst-triggered regulation of Ca2+ channels and pumps strengthens the intracellular Ca2+ accumulation. Especially, the exogenous ultrasound stimulation further amplifies mitochondrial damage. Both in vitro and in vivo experimental results affirm the ultrasound-augmented enzyodynamic-Ca2+ overload synergetic tumor inhibition outcomes. This study highlights the role of ultrasound coupled with functional nanozyme in the homeostasis imbalance and function disorder of mitochondria for highly efficient tumor treatment.

Based on polydopamine-coated metal organic framework multifunctional nanoplatform for enhanced photothermal/sonodynamicand treatment combined with checkpoint blockade therapy

To overcome the low efficacy of sonodynamic therapy (SDT) caused by hypoxia in the tumor microenvironment, we developed a multiple anti-tumor nanoplatform with synergistic SDT, photothermal therapy (PTT), and ferroptosis effects. PCN-224@FcCaO2/Mn/dihydroartemisinin/imiquimod/PDA (PFC) was prepared by modified with dihydroartemisinin (DHA), imiquimod (R837), CaO2, ferrocene (Fc) and Mn2+ on the PCN-224 (Cu) to achieve self-replenishment of H2O2/O2 and GSH consumption. FcCaO2 decomposed into H2O2 in the tumor microenvironment, triggering the Fenton effect to produce OH, and Cu2+ reduced the potential loss of OH by the depletion of GSH. Under ultrasonic (US) and laser irradiation, PFC exhibits exciting PTT and SDT effects from polydopamine (PDA) and PCN-224. Mn2+ not only promoted the reaction of H2O2 to produce O2 to effectively enhance SDT but also induced tumor cell apoptosis by Mn2+ combined with DHA. PFC induced ferroptosis via Fe interaction with DHA to produce ROS and reduce the expression of GPX4. The released R837 and tumor-associated antigens from SDT/PTT can produce damage associated molecular patterns (DAMPs), which can initiate adaptive immune responses to kill cancer cells, and released again to promote the tumor immune cycle. What's more, SDT/PTT and ferroptosis combined with aPD-L1 can effectively suppress both primary and distant tumor growth.

Remodeling Microenvironment for Implant-Associated Osteomyelitis by Dual Metal Peroxide

Implant-associated osteomyelitis (IAOM) is characterized by bone infection and destruction; current therapy of antibiotic treatment and surgical debridement often results in drug resistance and bone defect. It is challenging to develop an antibiotic-free bactericidal and osteogenic-enhanced strategy for IAOM. Herein, an IAOM-tailored antibacterial and osteoinductive composite of copper (Cu)-strontium (Sr) peroxide nanoparticles (CSp NPs), encapsulated in polyethylene glycol diacrylate (PEGDA) (CSp@PEGDA), is designed. The dual functional CSp NPs display hydrogen peroxide (H2O2) self-supplying and Fenton catalytic Cu2+ ions' release, generating plenty of hydroxyl radical (•OH) in a pH-responsive manner for bacterial killing, while the released Sr2+ promotes the in vitro osteogenicity regarding cell proliferation, alkaline phosphatase activity, extracellular matrix calcification, and osteo-associated genes expression. The integration of Cu2+ and Sr2+ in CSp NPs together with the coated PEGDA hydrogel ensures the stable and sustainable ion release during short- and long-term periods. Benefitted from the injectablity and photo-crosslink ability, CSp@PEGDA is able to thoroughly fill the infectious site and gelate in situ for bacterial elimination and bone regeneration, which is verified through in vivo evaluation using a clinical-simulating IAOM mouse model. These favorable abilities of CSp@PEGDA precisely meet the multiple therapeutic needs and pave a promising way for implant-associated osteomyelitis treatment.

Tumor Microenvironment Specific Regulation Ca-Fe-Nanospheres for Ferroptosis-Promoted Domino Synergistic Therapy and Tumor Immune Response

Reactive oxygen species (ROS)-mediated emerging treatments exhibit unique advantages in cancer therapy in recent years. While the efficacy of ROS-involved tumor therapy is greatly restricted by complex tumor microenvironment (TME). Herein, a dual-metal CaO2@CDs-Fe (CCF) nanosphere, with TME response and regulation capabilities, are proposed to improve ROS lethal power by a multiple cascade synergistic therapeutic strategy with domino effect. In response to weak acidic TME, CCF will decompose, accompanied with intracellular Ca2+ upregulated and abundant H2O2 and O2 produced to reverse antitherapeutic TME. Then the exposed CF cores can act as both Fenton agent and sonosensitizer to generate excessive ROS in the regulated TME for enhanced synergistic CDT/SDT. In combination with calcium overloading, the augmented ROS induced oxidative stress will cause more severe mitochondrial damage and cellular apoptosis. Furthermore, CCF can also reduce GPX4 expression and enlarge the lipid peroxidation, causing ferroptosis and apoptosis in parallel. These signals of damage will finally initiate damage-associated molecular patterns to activate immune response and to realize excellent antitumor effect. This outstanding domino ROS/calcium loading synergistic effect endows CCF with excellent anticancer effect to efficiently eliminate tumor by apoptosis/ferroptosis/ICD both in vitro and in vivo.

Advances in Nanomaterials for Immunotherapeutic Improvement of Cancer Chemotherapy

Immuno-stimulative effect of chemotherapy (ISECT) is recognized as a potential alternative to conventional immunotherapies, however, the clinical application is constrained by its inefficiency. Metronomic chemotherapy, though designed to overcome these limitations, offers inconsistent results, with effectiveness varying based on cancer types, stages, and patient-specific factors. In parallel, a wealth of preclinical nanomaterials holds considerable promise for ISECT improvement by modulating the cancer-immunity cycle. In the area of biomedical nanomaterials, current literature reviews mainly concentrate on a specific category of nanomaterials and nanotechnological perspectives, while two essential issues are still lacking, i.e., a comprehensive analysis addressing the causes for ISECT inefficiency and a thorough summary elaborating the nanomaterials for ISECT improvement. This review thus aims to fill these gaps and catalyze further development in this field. For the first time, this review comprehensively discusses the causes of ISECT inefficiency. It then meticulously categorizes six types of nanomaterials for improving ISECT. Subsequently, practical strategies are further proposed for addressing inefficient ISECT, along with a detailed discussion on exemplary nanomedicines. Finally, this review provides insights into the challenges and perspectives for improving chemo-immunotherapy by innovations in nanomaterials.

A ROS storm generating nanocomposite for enhanced chemodynamic therapy through H2O2 self-supply, GSH depletion and calcium overload

Catalytic generation of toxic hydroxyl radicals (˙OH) from hydrogen peroxide (H2O2) is an effective strategy for tumor treatment in chemodynamic therapy (CDT). However, the intrinsic features of the microenvironment in solid tumors, characterized by limited H2O2 and overexpressed glutathione (GSH), severely impede the accumulation of intracellular ˙OH, posing significant challenges. To circumvent these critical issues, in this work, a CaO2-based multifunctional nanocomposite with a surface coating of Cu2+ and L-buthionine sulfoximine (BSO) (named CaO2@Cu-BSO) is designed for enhanced CDT. Taking advantage of the weakly acidic environment of the tumor, the nanocomposite gradually disintegrates, and the exposed CaO2 nanoparticles subsequently decompose to produce H2O2, alleviating the insufficient supply of endogenous H2O2 in the tumor microenvironment (TME). Furthermore, Cu2+ detached from the surface of CaO2 is reduced by H2O2 and GSH to Cu+ and ROS. Then, Cu+ catalyzes H2O2 to generate highly cytotoxic ˙OH and Cu2+, forming a cyclic catalysis effect for effective CDT. Meanwhile, GSH is depleted by Cu2+ ions to eliminate possible ˙OH scavenging. In addition, the decomposition of CaO2 by TME releases a large amount of free Ca2+, resulting in the accumulation and overload of Ca2+ and mitochondrial damage in tumor cells, further improving CDT efficacy and accelerating tumor apoptosis. Besides, BSO, a molecular inhibitor, decreases GSH production by blocking γ-glutamyl cysteine synthetase. Together, this strategy allows for enhanced CDT efficiency via a ROS storm generation strategy in tumor therapy. The experimental results confirm and demonstrate the satisfactory tumor inhibition effect both in vitro and in vivo.

Bioinspired Tumor Calcification-Guided Early Diagnosis and Eradication of Hepatocellular Carcinoma

Tumor calcification is found to be associated with the benign prognostic, and which shows considerable promise as a somewhat predictive index of the tumor response clinically. However, calcification is still a missing area in clinical cancer treatment. A specific strategy is proposed for inducing tumor calcification through the synergy of calcium peroxide (CaO2)-based microspheres and transcatheter arterial embolization for the treatment of hepatocellular carcinoma (HCC). The persistent calcium stress in situ specifically leads to powerful tumor calcioptosis, resulting in diffuse calcification and a high-density shadow on computed tomography that enables clear localization of the in vivo tumor site and partial delineation of tumor margins in an orthotopic HCC rabbit model. This osmotic calcification can facilitate tumor clinical diagnosis, which is of great significance in differentiating tumor response during early follow-up periods. Proteome and phosphoproteome analysis identify that calreticulin (CALR) is a crucial target protein involved in tumor calcioptosis. Further fluorescence molecular imaging analysis also indicates that CALR can be used as a prodromal marker of calcification to predict tumor response at an earlier stage in different preclinical rodent models. These findings suggest that upregulated CALR in association with tumor calcification, which may be broadly useful for quick visualization of tumor response.

H2O2 self-supplying and GSH-depleting nanosystem for amplified NIR mediated-chemodynamic therapy of MRSA biofilm-associated infections

Reactive oxygen species (ROS) has emerged as potent therapeutic agents for biofilm-associated bacterial infections. Chemodynamic therapy (CDT), involving the generation of high-energy ROS, displays great potential in the therapy of bacterial infections. However, challenges such as insufficient hydrogen peroxide (H2O2) and over-expressed glutathione (GSH) levels within the microenvironment of bacterial biofilms severely limit the antibacterial efficacy of CDT. Herein, we have developed a multifunctional nanoplatform (CuS@CaO2@Dex) by integrating copper sulfide (CuS) and calcium peroxide (CaO2) into dextran (Dex)-coated nanoparticles. This innovative platform enhanced ROS generation for highly efficient biofilm elimination by simultaneously supplying H2O2 and depleting GSH. The Dex-coating facilitated the penetrability of CuS@CaO2@Dex into biofilms, while CaO2 generated a substantial amount of H2O2 in the acidic biofilm microenvironment. CuS, through a Fenton-like reaction, catalyzed the conversion of self-supplied H2O2 into hydroxyl radicals (•OH) and consumed the overexpressed GSH. Additionally, the incorporation of near-infrared II (NIR II) laser irradiation enhanced the photothermal properties of CuS, improving the catalytic efficiency of the Fenton-like reaction for enhanced antibacterial effects. In vivo experiments have demonstrated that CuS@CaO2@Dex exhibited remarkable antibacterial and antibiofilm efficacy, exceptional wound healing capabilities, and notable biosafety. In summary, the Dex-coated nanoplatform proposed in this study, with its self-sterilization capability through ROS, holds significant potential for future biomedical applications.

Apoptosis and Paraptosis Induced by Disulfiram-Loaded Ca2+/Cu2+ Dual-Ions Nano Trap for Breast Cancer Treatment

Regarded as one of the hallmarks of tumorigenesis and tumor progression, the evasion of apoptotic cell death would also account for treatment resistance or failure during cancer therapy. In this study, a Ca2+/Cu2+ dual-ion "nano trap" to effectively avoid cell apoptosis evasion by synchronously inducing paraptosis together with apoptosis was successfully designed and fabricated for breast cancer treatment. In brief, disulfiram (DSF)-loaded amorphous calcium carbonate nanoparticles (NPs) were fabricated via a gas diffusion method. Further on, the Cu2+-tannic acid metal phenolic network was embedded onto the NPs surface by self-assembling, followed by mDSPE-PEG/lipid capping to form the DSF-loaded Ca2+/Cu2+ dual-ions "nano trap". The as-prepared nanotrap would undergo acid-triggered biodegradation upon being endocytosed by tumor cells within the lysosome for Ca2+, Cu2+, and DSF releasing simultaneously. The released Ca2+ could cause mitochondrial calcium overload and lead to hydrogen peroxide (H2O2) overexpression. Meanwhile, Ca2+/reactive oxygen species-associated mitochondrial dysfunction would lead to paraptosis cell death. Most importantly, cell paraptosis could be further induced and strengthened by the toxic dithiocarbamate (DTC)-copper complexes formed by the Cu2+ combined with the DTC, the metabolic products of DSF. Additionally, the released Cu2+ will be reduced by intracellular glutathione to generate Cu+, which can catalyze the H2O2 to produce a toxic hydroxyl radical by a Cu+-mediated Fenton-like reaction for inducing cell apoptosis. Both in vitro cellular assays and in vivo antitumor evaluations confirmed the cancer therapeutic efficiency by the dual ion nano trap. This study can broaden the cognition scope of dual-ion-mediated paraptosis together with apoptosis via a multifunctional nanoplatform.

Red blood cell membrane-coated functionalized Cu-doped metal organic framework nanoformulations as a biomimetic platform for improved chemo-/chemodynamic/photothermal synergistic therapy

Nanoformulations for combining chemotherapy, chemodynamic therapy, and photothermal therapy have enormous potential in tumor treatment. Coating nanoformulations with cell membranes endows them with homologous cellular mimicry, enabling nanoformulations to acquire new functions and properties, including homologous targeting and long circulation in vivo, and can enhance internalization by homologous cancer cells. Herein, we fused multifunctional biomimetic nanoformulations based on Cu-doped zeolitic imidazolate framework-8 (ZIF-8). Hydroxycamptothecin (HCPT), a clinical anti-tumor drug, was encapsulated into ZIF-8, which was subsequently coated with polydopamine (PDA) and red blood cell membrane. The as-fabricated biomimetic nanoformulations showed an enhanced cell uptake in vitro and the potential to prolong blood circulation in vivo, producing effective synergistic chemotherapy, chemodynamic therapy, and photothermal therapy under the 808 nm laser irradiation. Together, the biomimetic nanoformulations showed a prolonged blood circulation and evasion of immune recognition in vivo to provide a bio-inspired strategy which may have the potential for the multi-synergistic therapy of breast cancer.

Manipulating calcium homeostasis with nanoplatforms for enhanced cancer therapy

Calcium ions (Ca2+) are indispensable and versatile metal ions that play a pivotal role in regulating cell metabolism, encompassing cell survival, proliferation, migration, and gene expression. Aberrant Ca2+ levels are frequently linked to cell dysfunction and a variety of pathological conditions. Therefore, it is essential to maintain Ca2+ homeostasis to coordinate body function. Disrupting the balance of Ca2+ levels has emerged as a potential therapeutic strategy for various diseases, and there has been extensive research on integrating this approach into nanoplatforms. In this review, the current nanoplatforms that regulate Ca2+ homeostasis for cancer therapy are first discussed, including both direct and indirect approaches to manage Ca2+ overload or inhibit Ca2+ signalling. Then, the applications of these nanoplatforms in targeting different cells to regulate their Ca2+ homeostasis for achieving therapeutic effects in cancer treatment are systematically introduced, including tumour cells and immune cells. Finally, perspectives on the further development of nanoplatforms for regulating Ca2+ homeostasis, identifying scientific limitations and future directions for exploitation are offered.

Macrophage-membrane-coated hybrid nanoparticles with self-supplied hydrogen peroxide for enhanced chemodynamic tumor therapy

Addressing the challenges of chemodynamic therapies (CDTs) relying on Fenton reactions in malignant tumors is an active research area. Here, we report a method to develop pH-responsive hybrid nanoparticles for enhanced chemodynamic tumor treatment. Reactive CaO2 nanoparticles (core) are isolated by biocompatible ZIF-8 doped with Fe2+ (shell), and then encapsulated by macrophage membranes (symbolized as CaO2@Fe-ZIF-8@macrophage membrane or CFZM), thus endowed with high stability under normal physiological conditions. Our design features active tumor-homing by the macrophage-membrane coating, tumor microenvironment (TME)-responsive cargo release, and self-supplied hydrogen peroxide for promotion of the Fenton reaction. We demonstrate the improved delivery/tumor cell uptake of CFZM, the efficient production of toxic ˙OH with self-supplied H2O2 in CFZM, and high-efficacy tumor ablation on BALB/c mice bearing CT26 tumor cells. This offers a translational strategy to develop active tumor-targeting and TME-responsive nanotherapeutics with enhanced CDT against malignant tumors.

Development of a fluorescent sensor based on TPE-Fc and GSH-AuNCs for the detection of organophosphorus pesticide residues in vegetables

A novel dual-signal fluorescent sensor was developed for detecting organophosphorus pesticides (OPs). It relies on the catalytic activities of acetylcholinesterase (AChE) and choline oxidase (ChOx) to generate hydrogen peroxide (H2O2) through the conversion of acetylcholine (ACh) to choline·H2O2 then oxidizes ferrocene-modified tetraphenylethylene (TPE-Fc) to its oxidized state (TPE-Fc+), resulting in enhanced cyan fluorescence due to aggregation. Simultaneously, ferrocene oxidation generates hydroxyl radicals (•OH), causing a decrease in orange fluorescence of glutathione-synthesized gold nanoclusters (GSH-AuNCs). The presence of OPs restricts AChE activity, reducing H2O2 production. Increasing OPs concentration leads to decreased cyan fluorescence and increased orange fluorescence, enabling visual OPs detection. The sensor has a linear dynamic range of 10-2000 ng/mL with a detection limit of 2.05 ng/mL. Smartphone-based color identification and a WeChat mini program were utilized for rapid OPs analysis with successful outcomes.

Synergistic Effects of Nanoscale CaO2 Combined with PD-1 Inhibitors in the Treatment of Hepatocellular Carcinoma: A Promising Combination

Purpose

To explore the effect of calcium peroxide nanoparticles (CaO2 NPs) combined with programmed cell death protein 1 (PD-1) inhibitors in the treatment of liver cancer and its related mechanism.

Methods

Hepa1-6 cells were cultured to construct the Hepa1-6 mouse liver cancer model. In vivo mechanism study, a unilateral tumor model was established. Eighteen tumor-bearing mice were randomly divided into the control group (intra-tumoral injection of PBS solution) and the experimental group (intra-tumoral injection of CaO2 NPs). A hypoxic probe, pH probe, and micro-CT were used to evaluate the effect of CaO2 NPs on improving hypoxia, neutralizing acidity, and inducing calcium overload within the tumor. To study the effect of CaO2 NPs combined with PD-1 inhibitors on proximal and distal tumors, the bilateral tumor model was established. Forty tumor-bearing mice were randomly divided into the control group (intra-tumoral/intra-peritoneal injection of PBS solution), CaO2 NPs group (intra-tumoral injection of CaO2 NPs), PD-1 group (intra-peritoneal injection of PD-1 inhibitor), and the combination group (intra-tumoral injection of CaO2 NPs and intra-peritoneal injection of PD-1 inhibitors). The administered side was recorded as the proximal tumor. Tumor volume and body weight were measured every 2 days after treatment. On day 8, serum and tumor samples were collected. The immune factors in serum (Interferon-γ (IFN-γ), Tumour necrosis factor-α (TNF-α), Interleukin-2 (IL-2), and Interleukin-10 (IL-10)) and tumor tissue (IFN-γ and TNF-α) were detected by ELISA. H&E staining was used to detect tumor necrosis. Immunohistochemical staining was used to detect the amount of CD4+ and CD8+ T cells within the tumor. By analyzing the tumor volume, pathological indexes, and immune-related indexes, the effects of CaO2 NPs combined with PD-1 inhibitors on proximal and distal tumors were evaluated, and they mediated immunomodulatory effects (including local and systemic immunity), and their effects on tumor burden were studied. In addition, a unilateral tumor model was established to study the effect of CaO2 NPs combined with PD-1 inhibitors on survival time.

Results

The results of in vivo mechanism study showed that CaO2 NPs can improve hypoxia, neutralize acidity, and induce calcium overload within tumors. The results of the study on the effect of CaO2 NPs combined with PD-1 inhibitor on proximal and distal tumors showed that, compared with the other three groups, the bilateral tumor burden of the combination group was significantly reduced, the intra-tumoral infiltration of CD8+ and CD4+ T cells were significantly increased, the secretion of anti-tumor immune factors in tumor and serum was increased, and the secretion of pro-tumor immune factors was decreased. Mice in the combination group showed the longest survival compared with the other groups.

Conclusion

CaO2 NPs can improve hypoxia, neutralize acidity, and induce calcium overload within tumors, so as to reduce tumor burden and realize an immunosuppressive tumor transformation to a hot tumor, and play a synergistic role with PD-1 inhibitors in anti-liver cancer.

Multifunctional Fe-based coordination polymer nano-bomb modified with β-lapachone and CaO2 for targeted tumor dual chemodynamic therapy with enhanced ferroptosis and H2O2 self-supply

Chemodynamic therapy (CDT) is seriously limited by the inadequacy of exogenous catalytic ions and endogenous H2O2 in tumors. Herein, a multifunction nano-bomb integrated with calcium peroxide (CaO2) and β-lapachone as donors of H2O2 and GSH-sensitive Fe-based coordination polymer as provider of catalytic ions was constructed for dual cascade-amplified tumor CDT. This hyaluronic acid (HA)-modified nano-bomb could be specially endocytosed by breast cancer cells through a targeting pathway, degraded and released cargoes in response to the GSH-rich cytoplasm. Furthermore, the released CaO2 and β-lapachone could significantly self-generated sufficient H2O2, which could dual-cascade amplify CDT and induce severe oxidative to tumors via cooperating with the delivered iron ions from nano-bombs. Moreover, the unloaded iron and calcium ions could further accelerate tumor damage by overloading Ca2+ and ferroptosis, as accompanied by good magnetic resonance imaging (MRI). In vitro and in vivo studies collectively reveal that this nano-bomb not only self-initiates double cascade-amplified CDT via self-generation of H2O2, but also efficiently activates ferroptosis and initiates Ca2+ overloading, consequently significantly tumor growth suppression. This study offers a novel tumor-initiated nano-bomb for dual cascade-amplified CDT and bioimaging with activated ferroptosis and self-supplying H2O2.

Folate-modified carboxymethyl chitosan-based drug delivery system for breast cancer specific combination therapy via regulating mitochondrial calcium concentration

Although various drug delivery systems that regulated Ca2+ concentration has been developed for tumor therapy, their application still presented significant challenges due to the complex preparation and introduction of a large number of inorganic molecules that might cause serious toxic effects. To solve these problems, a folate-functionalized carboxymethyl chitosan (CMCS)/calcium phosphate hybrid nanoparticle (CF/CaP) with Ca2+ production was designed to treat breast cancer combined with the Ca2+ inhibitory effect of encapsulated curcumin (Cur). It was demonstrated that the optimal CF/CaP nanoparticles loaded with Cur (C@CF/CaP) were spherical nanoparticles, which exhibited a smaller size at about 179 nm than non-targeted nanoparticles with size at about 234 nm. C@CF/CaP had good biocompatibility, high stability and acid responsive drug release. Compared with the neutral environment, the cumulative release of Cur was >70 % after culture for 36 h at pH 5.0. Compared with non-targeted nanoparticles, C@CF/CaP could specifically target tumor tissues and then enter tumor cells through folate receptor-mediated endocytosis. C@CF/CaP could cause mitochondrial Ca2+ overload, trigger the mitochondrial apoptotic pathway, destroy the mitochondrial structure and finally have good anti-tumor efficiency. The results proved that Ca2+ nanomodulators based on CMCS might provide a potential organelle targeting strategy for cancer therapy.

Engineering Crystallinity Gradients for Tailored CaO2 Nanostructures: Enabling Alkalinity-Reinforced Anticancer Activity with Minimized Ca2+/H2O2 Production

CaO2 nanoparticles (CNPs) can produce toxic Ca2+ and H2O2 under acidic pH, which accounts for their intrinsic anticancer activity but at the same time raises safety concerns upon systemic exposure. Simultaneously realizing minimized Ca2+/H2O2 production and enhanced anticancer activity poses a dilemma. Herein, we introduce a "crystallinity gradient-based selective etching" (CGSE) strategy, which is realized by creating a crystallinity gradient in a CNP formed by self-assembled nanocrystals. The nanocrystals distributed in the outer layer have a higher crystallinity and thus are chemically more robust than those distributed in the inner layer, which can be selectively etched. CGSE not only leads to CNPs with tailored single- and double-shell hollow structures and metal-doped compositions but more surprisingly enables significantly enhanced anticancer activity as well as tumor growth inhibition under limited Ca2+/H2O2 production, which is attributed to an alkalinity-reinforced lysosome-dependent cell death pathway.

Synergistic therapeutic effect of nanomotors triggered by Near-infrared light and acidic conditions of tumor

Due to the complexity of tumors, multimodal therapy for them has always been of concern to researchers. How to design a multifunctional drug nanoplatform with cascade effect and capable of responding to specific stimuli in the tumor microenvironment is the key to achieve efficient multimodal synergistic therapy of cancer. Here, we prepare a kind of GNRs@SiO2@PDA-CuO2-l-Arg (GSPRs-CL) nanomotors for systematic treatment of tumor. First, under near-infrared (NIR) irradiation, GSPRs-CL can generate heat and exhibit excellent photothermal therapy effect. Then under acidic conditions, CuO2 can be decomposed to release Cu2+ and generate H2O2, which not only complemented the limited endogenous H2O2 in cells, but also further triggered Fenton-like reaction, converting H2O2 into •OH to kill cancer cells, thereby achieving chemodynamic therapy. Furthermore, both endogenous and exogenous H2O2 can release nitric oxide (NO) in response to the occurrence of l-Arg of nanomotors to enhance gas therapy. In addition, as a dual-mode drive, NIR laser and NO can promote the penetration ability of nanomotors at tumor sites. The experimental results in vivo show that the drug nanoplatform had good biosafety and significant tumor killing effect triggered by NIR light and acidic conditions of tumor. It provide a promising strategy for the development of advanced drug nanoplatform for cancer therapy.

Recent progress of metal-based nanomaterials with anti-tumor biological effects for enhanced cancer therapy

Metal-based nanomaterials have attracted broad attention recently due to their unique biological physical and chemical properties after entering tumor cells, namely biological effects. In particular, the abilities of Ca2+ to modulate T cell receptors activation, K+ to regulate stem cell differentiation, Mn2+ to activate the STING pathway, and Fe2+/3+ to induce tumor ferroptosis and enhance catalytic therapy, make the metal ions and metal-based nanomaterials play crucial roles in the cancer treatments. Therefore, due to the superior advantages of metal-based nanomaterials and the characteristics of the tumor microenvironment, we will summarize the recent progress of the anti-tumor biological effects of metal-based nanomaterials. Based on the different effects of metal-based nanomaterials on tumor cells, this review mainly focuses on the following five aspects: (1) metal-enhanced radiotherapy sensitization, (2) metal-enhanced catalytic therapy, (3) metal-enhanced ferroptosis, (4) metal-enhanced pyroptosis, and (5) metal-enhanced immunotherapy. At the same time, the shortcomings of the biological effects of metal-based nanomaterials on tumor therapy are also discussed, and the future research directions have been prospected. The highlights of promising biosafety, potent efficacy on biological effects for tumor therapy, and the in-depth various biological effects mechanism studies of metal-based nanomaterials provide novel ideas for the future biological application of the nanomaterials.

Research progress of calcium carbonate nanomaterials in cancer therapy: challenge and opportunity

Cancer has keeping the main threat to the health of human being. Its overall survival rate has shown rare substantial progress in spite of the improving diagnostic and treatment techniques for cancer in recent years. Indeed, such classic strategies for malignant tumor as surgery, radiation and chemotherapy have been developed and bring more hope to the patients, but still been accompanied by certain limitations, which include the challenge of managing large wound sizes, systemic toxic side effects, and harmful to the healthy tissues caused by imprecise alignment with tumors in radiotherapy. Furthermore, immunotherapy exhibits a limited therapeutic effect in advanced tumors which is reported only up to 25%-30%. The combination of nanomaterials and cancer treatment offers new hope for cancer patients, demonstrating strong potential in the field of medical research. Among the extensively utilized nanomaterials, calcium carbonate nanomaterials (CCNM) exhibit a broad spectrum of biomedical applications due to their abundant availability, cost-effectiveness, and exceptional safety profile. CCNM have the potential to elevate intracellular Ca2+ levels in tumor cells, trigger the mitochondrial damage and ultimately lead to tumor cell death. Moreover, compared with other types of nanomaterials, CCNM exhibit remarkable advantages as delivery systems owing to their high loading capacity, biocompatibility and biodegradability. The purpose of this review is to provide an overview of CCNM synthesis, focusing on summarizing its diverse roles in cancer treatment and the benefits and challenges associated with CCNM in cancer therapy. Hoping to present the significance of CCNM as for the clinical application, and summarize information for the design of CCNM and other types of nanomaterials in the future.

Cell-surface photochemistry mediated calcium overload for synergistic tumor therapy

Calcium (Ca2+) is essential for mitochondrial homeostasis and function coordination, particularly in cancer cells that metabolize frequently to sustain their growth. Photochemistry mediated calcium overload has attracted lots of attention as an effective way to achieve tumor suppression. Herein, we developed a photonanomedicine to synergistically induce calcium overload via cell-surface photochemistry and thus tumor suppression. Specifically, the photosensitizer, protoporphyrin IX (PpIX) was loaded onto upconversion nanoparticles (UCNP), which was subsequently modified by a polymer bearing photo-crosslinking cinnamate (CA) groups. The resulting nanoparticle was further functionalized by anti-CD20 aptamers (Apt), to give photonanomedicine. The interaction between CD20 receptors and anti-CD20 aptamers allowed photonanomedicine to accurately attach onto the Raji cell surface after an intravenous injection. Following the local application of a 980 nm NIR laser, the photonanomedicine was able to capture the NIR light and convert it into ultraviolet (UV) light. On one hand, the converted UV light led the crosslinking of cinnamate groups in photonanomedicine, further stimulating the clustering of CD20 receptors and causing Ca2+ influx. On the other hand, the UV light could simultaneously excited PpIX to generate reactive oxygen species (ROS) in situ to break down the integrity of cell membrane and lead to an influx of Ca2+. The synergistic Ca2+ overload mediated by photonanomedicine exhibited an enhanced and superior anti-tumor efficacy. We believe this photonanomedicine expands the toolbox to manipulate intracellular Ca2+ concentration and holds a great potential as an anti-tumor therapy.

Responsive calcium-derived nanoassemblies induce mitochondrial disorder to promote tumor calcification

Physiological calcification of the treated tumor area is considered to be a predictor of good prognosis. Promoting tumor calcification by inducing mitochondrial metabolic disorder and destroying calcium equilibrium has a potential inhibitory effect on tumor proliferation. Here, by promoting calcification by inducing mitochondrial dysfunction combined with triggering a surge of reactive oxygen species, we construct a bioresponsive calcification initiator, termed CaP-AA, using CaHPO4 covalently doped l-ascorbic acid. CaHPO4 releases Ca2+ within the cytoplasm of tumor cells to trigger calcium overload. Meanwhile, exogenous l-ascorbic acid indirectly enhances metabolic balance disruption via pro-oxidant effects. Such Ca2+ overload increases the likelihood of tumor calcification in vivo for tumor inhibition by perturbing mitochondrial homeostasis. The introduction of responsive calcium sources that would, in turn, trigger intratumoral calcification mediated by perturbing mitochondrial homeostasis would be an effective regulatory strategy for tumor therapy.

CaO2nanomedicines: a review of their emerging roles in cancer therapy

Metal peroxide-based nanomedicines have emerged as promising theranostic agents for cancer due to their multifunctional properties, including the generation of bioactive small molecules such as metal ions, H2O2, O2, and OH-. Among these metal peroxides, calcium peroxide (CaO2) nanomedicines have attracted significant attention due to their facile synthesis and good biocompatibility. CaO2nanoparticles have been explored for cancer treatment through three main mechanisms: (1) the release of O2, which helps alleviate tumor hypoxia and enhances oxygen-dependent therapies such as chemotherapy, photodynamic therapy, and immunotherapy; (2) the generation of H2O2, a precursor for ·OH generation, which enables cancer chemodynamic therapy; and (3) the release of Ca2+ions, which induce calcium overload and promote cell apoptosis (called ion-interference therapy). This review provides a comprehensive summary of recent examples of CaO2nanoparticle-based cancer therapeutic strategies, as well as discusses the challenges and future directions in the development of CaO2nanomedicines for cancer treatment.

Biodegradable CuMoO4 Nanodots with Multienzyme Activities for Multimodal Treatment of Tumor

Due to their complexity and variability, tumors need to be treated with multimodal combined therapy, which requires the development of therapeutic agents that can provide multimodal therapeutic effects. Herein, CuMoO4 nanodots smaller than 10 nm that can be prepared by simple hydrothermal method are reported. These nanodots can be well dispersed in water and have good biosafety and biodegradability. Further studies show that these nanodots also present multienzyme activities, such as catalase, peroxidase and glutathione peroxidase. In addition, CuMoO4 nanodots exhibit high photothermal conversion efficiency (41%) under 1064 nm near-infrared laser irradiation. In vitro and in vivo experimental results indicate that CuMoO4 nanodots can effectively inhibit the instinctive regulation of tumor cells to oxidative stress, provide sustained treatment to achieve photothermal synergistic ferroptosis, and trigger immune responses to immunogenic cell death. It is worth mentioning that the CuMoO4 nanodots also cause cuproptosis of tumor cells. This study provides a promising nanoplatform for multimodal combined therapy of cancer.

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.

Cuproptosis-Inducible Chemotherapeutic/Cascade Catalytic Reactor System for Combating with Breast Cancer

Cascade hydroxyl radical generating hydrogel reactor structures including a chemotherapeutic agent are invented for multiple treatment of breast cancer. Glucose oxidase (GOx) and cupric sulfate (Cu) are introduced for transforming accumulated glucose (in cancer cells) to hydroxyl radicals for starvation/chemodynamic therapy. Cu may also suppress cancer cell growth via cuproptosis-mediated cell death. Berberine hydrochloride (BER) is engaged as a chemotherapeutic agent in the hydrogel reactor for combining with starvation/chemodynamic/cuproptosis therapeutic modalities. Moreover, Cu is participated as a gel crosslinker by coordinating with catechol groups in hyaluronic acid-dopamine (HD) polymer. Controlling viscoelasticity of hydrogel reactor can extend the retention time following local injection and provide sustained drug release patterns. Low biodegradation rate of designed HD/BER/GOx/Cu hydrogel can reduce dosing frequency in local cancer therapy and avoid invasiveness-related inconveniences. Especially, it is anticipated that HD/BER/GOx/Cu hydrogel system can be applied for reducing size of breast cancer prior to surgery as well as tumor growth suppression in clinical application.

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.

Integrated supramolecular nanovalves for photothermal augmented chemodynamic therapy through strengthened amplification of oxidative stress

The amplified oxidative stress strategy has been emerged as one promising method to enhance the chemodynamic therapy (CDT) efficacy due to the H₂O₂ up-regulation and glutathione (GSH) down-regulation behavior in tumor cells. However, how to further achieve the satisfied CDT efficacy is still a big challenge. In this paper, the supramolecular nanovalves (SNs) with oxidative amplification agents cinnamaldehyde-(phenylboronic acid pinacol ester) conjugates (CA-BE) encapsulated inside were developed to accelerate and amplify the generation of ·OH and consumption of GSH while augmenting the CDT efficacy. SNs were obtained through ferrocene/Au modified mesoporous silica nanoparticles (MSN@Au-Fc) and active targeting β-cyclodextrin modified hyaluromic acid (HA-CD). After CD44 receptor-mediated cellular internalization, the CA-BE were released to elevate H₂O₂ amount and consume GSH for the desired generation of higher cytotoxic hydroxyl radicals (·OH). Moreover, the NIR-activated MSN@Au-Fc can increase the temperature for the accelerated and amplified oxidative stress. As such, the therapeutic efficacy of our synthesized CA-BE and the accompanied hyperthermia were augmented toward synergistically inhibiting tumor growth.

Targeting tumor energy metabolism via simultaneous inhibition of mitochondrial respiration and glycolysis using biodegradable hydroxyapatite nanorods

Tumor cells obtain energy supply from the unique metabolic pathways of mitochondrial respiration and glycolysis, which can be used interchangeably to produce adenosine triphosphate (ATP) for survival. To simultaneously block the two metabolic pathways and sharply cut off ATP supply, a multifunctional "nanoenabled energy interrupter" (called as HNHA-GC) was prepared by attaching glucose oxidase (GOx), hyaluronic acid (HA), and 10-hydroxycamptothecin (CPT) on the surface of degradable hydroxyapatite (NHA) nanorods. After targeted delivery of HNHA-GC to the tumor site by HA, the tumor-selective acid degradation of HNHA-GC as well as the subsequent deliveries of Ca²⁺, drug CPT, and GOx take place. The released Ca²⁺ and CPT induce mitochondrial dysfunction by Ca²⁺ overload and chemotherapy respectively, while the GOx-triggered glucose oxidation inhibits glycolysis by starvation therapy (exogenous effect). The generated H₂O₂ and released CPT increase the intracellular reactive oxygen (ROS) level. Moreover, the generated H⁺ and enhanced ROS promote Ca²⁺ overload by accelerating the degradation of HNHA-GC and preventing intracellular Ca²⁺ efflux, respectively (endogenous effect). As a result, the HNHA-GC displays a promising therapeutic modality for simultaneously cutting off mitochondrial and glycolytic ATP production through a combination of Ca²⁺ overload, chemotherapy, and starvation therapy.

Electrochemical therapy (EChT) of cancer tumor with an external anode, a way to achieve pathological complete response

There is a critical need for re-evaluation of electrochemical therapy (EChT) approaches of solid tumors to address the challenges of the currently used method: incomplete pathological response. The coexistence of anode and cathode in the tumor region resulted in acid-alkaline mixation (buffered pH) when the electrodes are so near each other (d < 1 cm), and in the non-affected lesions when the electrodes are far from each other (d > 1 cm), both have resulted in intact tumoral lesions in EChT field. Here, we presented a designation model study of EChT with an external anode out of the tumor and filled the tumor with dense distribution of cathode electrodes to completely destroy the tumoral lesions without any remaining vital tumoral residues. Anode was located in a biological ionic gel chamber (located on top of the skin) which mediates the ionic interface between the external anode and intratumoral cathode. Our newly reported method can solve the lack of a comprehensive therapeutic guideline for any solid tumors. A remarkable increase in the efficiency of EChT without any over-treating was achieved by alkaline therapy of the tumor (without any limitation in locating cathodic needles all over the tumor) and an external acidic region on top of the skin in a cylindrical gel chamber. We found that the destructive volumes and treating ability of mice tumors by this newly represented method were more significant than the conventional EChT method in fewer therapy sessions and no damage to the skin (both anode and cathode electrodes inside the tumor) (P < 0.05). Results of this study applied to mouse model tumors shed new light on returning attraction to EChT as a valuable complementary method for treating different types of solid breast tumors.

Glutathione-responsive and -exhausting metal nanomedicines for robust synergistic cancer therapy

Due to their rapid and uncontrolled proliferation, cancer cells are characterized by overexpression of glutathione (GSH), which impairs reactive oxygen species (ROS)-based therapy and weakens the chemotherapeutic agent-induced toxification. Extensive efforts have been made in the past few years to improve therapeutic outcomes by depleting intracellular GSH. Special focus has been given to the anticancer applications of varieties of metal nanomedicines with GSH responsiveness and exhaustion capacity. In this review, we introduce several GSH-responsive and -exhausting metal nanomedicines that can specifically ablate tumors based on the high concentration of intracellular GSH in cancer cells. These include inorganic nanomaterials, metal-organic frameworks (MOFs), and platinum-based nanomaterials. We then discuss in detail the metal nanomedicines that have been extensively applied in synergistic cancer therapy, including chemotherapy, photodynamic therapy (PDT), sonodynamic therapy (SDT), chemodynamic therapy (CDT), ferroptotic therapy, and radiotherapy. Finally, we present the horizons and challenges in the field for future development.

WZ35 inhibits gastric cancer cell metastasis by depleting glutathione to promote cellular metabolic remodeling

This study aimed at elucidating the crosstalk between redox reaction and metabolic remodeling through uncovering the mechanism underlying WZ35-mediated reactive oxygen species (ROS) production and regulation of amino acid metabolism to inhibit gastric cancer (GC) cell metastasis. The activity and biosafety of curcumin analog, WZ35, were verified in vitro and in vivo. The potential molecular mechanism underlying WZ35-mediated enhanced radiotherapeutic sensitivity by reduced Glutathione (GSH) depletion was elucidated by RNA sequencing, single-cell sequencing (scRNA-seq), metabolic mass spectrometry, and other molecular experiments. Compared to curcumin, WZ35 proved more potent anti-proliferative and anti-metastasis properties. Importantly, we demonstrated that WZ35 could consume GSH in multiple ways, including by reduction of raw materials and consumption reserves, inhibition of reformation, and enhanced decomposition. Mechanistically, we identify that WZ35 maintains the GSH depletion phenotype through the ROS-YAP-AXL-ALKBH5-GLS2 loop, further backing the relevance of metabolic remodeling in the tumor microenvironment with tumor metastasis and the role of m⁶A in tumor metastasis. Collectively, our study identified WZ35 as a novel GSH depletion agent and a previously undiscovered GSH depletion loop mechanism in GC cell metastasis.

Silencing the Catalase Gene with SiRNA for Enhanced Chemodynamic Therapy

Chemodynamic therapy (CDT) has been emerging as a promising strategy for cancer treatment. But the CDT efficiency is restricted by the insufficient intracellular hydrogen peroxide (H2O2) level. Herein, we present a method for H2O2 accumulation in tumor cells by silencing the catalase (CAT) gene with siRNA to achieve enhanced CDT. Cu-siRNA nanocomposites are fabricated by self-assembly of Cu2+ and CAT siRNA and then modified with hyaluronic acid (HA) for active tumor targeting. After tumor cell uptake, the released Cu2+ is reduced by highly expressed glutathione (GSH) to Cu+, which then catalyzes H2O2 to produce toxic hydroxyl radicals (•OH) to kill tumor cells. CAT siRNA can efficiently silence the CAT mRNA to inhibit the consumption of H2O2, resulting in H2O2 accumulation. The Cu2+-mediated GSH elimination and siRNA-induced endogenous H2O2 enrichment both potentiate CDT. Cu-siRNA@HA exhibits good biocompatibility and therapeutic efficiency. This work thus paves a new way to supply H2O2 in CDT and may hold potential for clinical application.

Self-intensified synergy of a versatile biomimetic nanozyme and doxorubicin on electrospun fibers to inhibit postsurgical tumor recurrence and metastasis

Tumor-positive resection margins after surgery can result in tumor recurrence and metastasis. Although adjuvant postoperative radiotherapy and chemotherapy have been adopted in clinical practice, they lack efficacy and result in unavoidable side effects. Herein, a self-intensified in-situ therapy approach using electrospun fibers loaded with a biomimetic nanozyme and doxorubicin (DOX) is developed. The fabricated PEG-coated zeolite imidazole framework-67 (PZIF67) is demonstrated as a versatile nanozyme triggering reactions in cancer cells based on endogenous H₂O₂ and •O₂^-. The PZIF67-generated •OH induces reactive oxygen species (ROS) overload, implementing chemodynamic therapy (CDT). The O₂ produced by PZIF67 inhibits the expression of hypoxia-up-regulated proteins, thereby suppressing tumor progression. PZIF67 also catalyzes the degradation of glutathione, further disturbing the intracellular redox homeostasis and enhancing CDT. Furthermore, the introduced DOX not only kills cancer cells individually, but also replenishes the continuously consumed substrates for PZIF67-catalyzed reactions. The PZIF67-weakened drug resistance strengthens the cytotoxicity of DOX. The combined application of PZIF67 and DOX also suppresses metastasis-associated genes. Both in vitro and in vivo results demonstrate that the self-intensified synergy of PZIF67 and DOX on electrospun fibers efficiently prevents postsurgical tumor recurrence and metastasis, offering a feasible therapeutic regimen for operable malignant tumors.

Site-specific nanomodulator capable of modulation apoptosis for enhanced colorectal cancer chemo-photothermal therapy

BACKGROUND

Colorectal cancer (CRC) is a common malignancy with the second highest mortality and the third highest morbidity worldwide. However, the overall survival of patients is unsatisfactory, thus requiring more effective clinical strategies. Celastrol (CLT), a natural bioactive compound, has been reported to induce reactive oxygen species (ROS)-mediated apoptosis to exhibit significant antitumor effects against CRC. However, the poor water solubility, low targeting ability, and bioavailability of CLT have limited its application, and CLT-induced protective autophagy weakens its therapeutic efficiency.

RESULTS

We designed a targeted chemo-phototherapy nanoplatform (HCR NPs) to improve the application of CLT. The codelivery of IR820 and CLT in HCR NPs solved the water-soluble problem of CLT and enhanced apoptosis via IR820-mediated hyperthermia. In addition, hydroxychloroquine (HCQ) conjugated to hyaluronic acid (HA) not only increased the active targeting of HCR NPs but also inhibited CLT-induced protective autophagy to exacerbate apoptosis, thus achieving an amplified antitumor effect. Importantly, the HCR NPs exhibited an excellent therapeutic effect on CRC both in vitro and in vivo.

CONCLUSION

The HCR NPs presented in this study may not merely provide a new reference for the clinical application of CLT but also result in an attractive strategy for CRC treatment.

The role of lipid metabolic reprogramming in tumor microenvironment

Metabolic reprogramming is one of the most important hallmarks of malignant tumors. Specifically, lipid metabolic reprogramming has marked impacts on cancer progression and therapeutic response by remodeling the tumor microenvironment (TME). In the past few decades, immunotherapy has revolutionized the treatment landscape for advanced cancers. Lipid metabolic reprogramming plays pivotal role in regulating the immune microenvironment and response to cancer immunotherapy. Here, we systematically reviewed the characteristics, mechanism, and role of lipid metabolic reprogramming in tumor and immune cells in the TME, appraised the effects of various cell death modes (specifically ferroptosis) on lipid metabolism, and summarized the antitumor therapies targeting lipid metabolism. Overall, lipid metabolic reprogramming has profound effects on cancer immunotherapy by regulating the immune microenvironment; therefore, targeting lipid metabolic reprogramming may lead to the development of innovative clinical applications including sensitizing immunotherapy.

O2-Supplying Nanozymes Alleviate Hypoxia and Deplete Lactate to Eliminate Tumors and Activate Antitumor Immunity

Direct hypoxia alleviation and lactate depletion in the tumor microenvironment (TME) are promising for effective cancer therapy but still very challenging. To address this challenge, the current research directly reshapes the TME for inhibiting tumor growth and activating the antitumor immunity using a drug-free nanozyme. Herein, the acid-sensitive nanozymes were constructed based on peroxidized layered double hydroxide nanoparticles for O₂ self-supply and self-boosted lactate depletion. The coloading of partially cross-linked catalase and lactate oxidase enabled the acid-sensitive nanozymes to promote three reactions, that is, (1) H₂O₂ generation from MgO₂ hydrolysis (30% at pH 7.4 vs 63% at pH 6.0 in 8 h); (2) O₂ generation from H₂O₂ (12% at pH 7.4 vs 21% at pH 6.0 in 2 h); and (3) lactate depletion by in situ generated O₂ (50% under hypoxia vs 75% under normoxia in 24 h in vitro) in parallel or tandem. These promoted reactions together efficiently induced colon cancer cell apoptosis under the hypoxic conditions, significantly inhibited tumor growth (>95%), and suppressed distant tumor growth upon seven administrations in every 3 days and moreover transformed the immunosuppressive tumor into "hot" one in the colon tumor-bearing mouse model. This is the first example for a nanozyme that supplies sufficient O₂ for hypoxia relief and lactate depletion, thus providing a new insight into drug-free nanomaterial-mediated TME-targeted cancer therapy.