Nanoscale Copper(II)-Diethyldithiocarbamate Coordination Polymer as a Drug Self-Delivery System for Highly Robust and Specific Cancer Therapy

Copper-Consuming Nanoplatform for Alleviating Hypoxia and Overcoming Resistance to Sonodynamic Therapy of Breast Cancer

Sonodynamic therapy (SDT) is a promising treatment modality for breast cancer; however, its effectiveness is often impeded by the hypoxic tumor microenvironment owing to an insufficient oxygen supply in the solid tumors. To overcome this challenge, we elaborately developed a 4T1 tumor-targeted multifunctional nanoagent by integrating both dendrimer-structured copper chelating agents and organic sonosensitizers (IR820) into a biotin-modified nanoliposome via a microfluidic-assisted self-assembly. In particular, the aforementioned copper chelating agent was constructed by introducing multiple xanthate groups into a dendrimer polymer, which showed a significant selectivity for the consumption of the intracellular copper levels. Based on this, the nanoliposome-based therapeutic not only disrupted the activity of the mitochondrial complex IV to directly inhibit the tumor cell proliferation but also suppressed the resistance to the SDT via inhibition of the oxygen consumption for cellular respiration. Both in vitro and in vivo studies confirmed that the designed nanoagents exhibit a synergistic tumor inhibition effect of copper consumption and IR820-mediated SDT. Taken together, this approach establishes a proof-of-concept for the construction of a copper-ion-modulated nanomedicine to significantly enhance the efficiency of oxygen-dependent cancer treatments.

Copper Deposition in Polydopamine Nanostructure to Promote Cuproptosis by Catalytically Inhibiting Copper Exporters of Tumor Cells for Cancer Immunotherapy

Cuproptosis is an emerging programmed cell death, displaying great potential in cancer treatment. However, intracellular copper content to induce cuproptosis is unmet, which mainly ascribes to the intracellular pumping out equilibrium mechanism by copper exporter ATP7A and ATP7B. Therefore, it is necessary to break such export balance mechanisms for desired cuproptosis. Mediated by diethyldithiocarbamate (DTC) coordination, herein a strategy to efficiently assemble copper ions into polydopamine nanostructure (PDA-DTC/Cu) for reprogramming copper metabolism of tumor is developed. The deposited Cu2+ can effectively trigger the aggregation of lipoylated proteins to induce cuproptosis of tumor cells. Beyond elevating intracellular copper accumulation, PDA-DTC/Cu enables to break the balance of copper metabolism by disrupting mitochondrial function and restricting the adenosine triphosphate (ATP) energy supply, thus catalytically inhibiting the expressions of ATP7A and ATP7B of tumor cells to enhance cuproptosis. Meanwhile, the killed tumor cells can induce immunogenic cell death (ICD) to stimulate the immune response. Besides, PDA-DTC/Cu NPs can promote the repolarization of tumor-associated macrophages (TAMs ) to relieve the tumor immunosuppressive microenvironment (TIME). Collectively, PDA-DTC/Cu presented a promising "one stone two birds" strategy to realize copper accumulation and inhibit copper export simultaneously to enhance cuproptosis for 4T1 murine breast cancer immunotherapy.

Repurposing disulfiram with CuET nanocrystals: Enhancing anti-pyroptotic effect through NLRP3 inflammasome inhibition for treating inflammatory bowel diseases

Drug repurposing offers a valuable strategy for identifying new therapeutic applications for existing drugs. Recently, disulfiram (DSF), a drug primarily used for alcohol addiction treatment, has emerged as a potential treatment for inflammatory diseases by inhibiting pyroptosis, a form of programmed cell death. The therapeutic activity of DSF can be further enhanced by the presence of Cu2+, although the underlying mechanism of this enhancement remains unclear. In this study, we investigated the mechanistic basis of Cu2+-induced enhancement and discovered that it is attributed to the formation of a novel copper ethylthiocarbamate (CuET) complex. CuET exhibited significantly stronger anti-pyroptotic activity compared to DSF and employed a distinct mechanism of action. However, despite its potent activity, CuET suffered from poor solubility and limited permeability, as revealed by our druggability studies. To overcome these intrinsic limitations, we developed a scalable method to prepare CuET nanocrystals (CuET NCs) using a metal coordination-driven self-assembly approach. Pharmacokinetic studies demonstrated that CuET NCs exhibited a 6-fold improvement in bioavailability. Notably, CuET NCs exhibited high biodistribution in the intestine, suggesting their potential application for the treatment of inflammatory bowel diseases (IBDs). To evaluate their therapeutic efficacy in vivo, we employed a murine model of DSS-induced colitis and observed that CuET NCs effectively attenuated inflammation and ameliorated colitis symptoms. Our findings highlight the discovery of CuET as a potent anti-pyroptotic agent, and the development of CuET NCs represents a novel approach to enhance the druggability of CuET.

Nanomedicine-based disulfiram and metal ion co-delivery strategies for cancer treatment

Disulfiram (DSF) is a second-line drug for the clinical treatment of alcoholism and has long been proven to be safe for use in clinical practice. In recent years, researchers have discovered the cancer-killing activity of DSF, which is highly dependent on the presence of metal ions, particularly copper ions. Additionally, free DSF is highly unstable and easily degraded within few minutes in blood circulation. Therefore, an ideal DSF formulation should facilitate the co-delivery of metal ions and safeguard the DSF throughout its biological journey before reaching the targeted site. Extensive research have proved that nanotechnology based formulations can effectively realize this goal by strategic encapsulation therapeutic agents within nanoparticle. To be more specific, this is accomplished through precise delivery, coordinated release of metal ions at the tumor site, thereby amplifying its cytotoxic potential. Beyond traditional co-loading techniques, innovative approaches such as DSF-metal complex and metal nanomaterials, have also demonstrated promising results at the animal model stage. This review aims to elucidate the anticancer mechanism associated with DSF and its reliance on metal ions, as well as to provide a comprehensive overview of recent advances in the arena of nanomedicine based co-delivery strategies for DSF and metal ion in the context of cancer therapy.

Polydopamine-Modified Copper Coordination Mesoporous Silica Nanoparticles Loaded with Disulfiram for Synergistic Chemo-Photothermal Therapy

Disulfiram (DSF) degrades to diethyldithiocarbamate (DTC) in vivo and coordinates with copper ions to form CuET, which has higher antitumor activity. In this study, DSF@CuMSN-PDA nanoparticles were prepared using mesoporous silica with copper ions, DSF as a carrier, and polydopamine (PDA) as a gate system. The nanoparticles selectively released CuET into tumor tissue by taking advantage of the tumor microenvironment, where PDA could be degraded. The release ratio reached 79.17% at pH 5.0, indicating pH-responsive drug release from the nanoparticles. The PDA-gated system provided the nanoparticles with unique photothermal conversion performance and significantly improved antitumor efficiency. In vivo, antitumor experiments showed that the designed DSF@CuMSN-PDA nanoparticles combined with near-infrared light (808 nm, 1 W/cm2) irradiation effectively inhibited tumor growth in HCT116 cells by harnessing the combined potential of chemotherapy and photothermal therapy; a synergistic effect was achieved. Taken together, these results suggest that the designed DSF@CuMSN-PDA construct can be employed as a promising candidate for combined chemo-photothermal therapy.

Morphology Control of Self-Assembled Copper Coordination Polymers for Glucose Assays

Low-cost analytical assays enable accessible detection of clinically and environmentally important analytes; however, common enzyme-based assays suffer from high production and storage costs. Catalytically active synthetic materials serve as replacements for natural enzymes, but development of cost-effective, highly efficient synthetic strategies remains a challenge. Here, we utilized a facile synthesis for copper bipyridine coordination polymers (CuBpyCPs) and investigated structure-function relationships to achieve optimal catalytic properties for a glucose assay. We demonstrated the manipulation of CuBpyCP morphology, resulting in nanoscale petal-like structures and microscale high-index faceted structures, and identified three pure crystal morphologies exhibiting a comparable catalytic activity (Km = 0.3-0.5 mM) to horseradish peroxidase.

Nanoscale coordination polymer Fe-DMY downregulating Poldip2-Nox4-H2O2 pathway and alleviating diabetic retinopathy

Diabetic retinopathy (DR) is a prevalent microvascular complication of diabetes and the leading cause of blindness and severe visual impairment in adults. The high levels of glucose trigger multiple intracellular oxidative stress pathways, such as POLDIP2, resulting in excessive reactive oxygen species (ROS) production and increased expression of vascular cell adhesion molecule-1 (VCAM-1), hypoxia-inducible factor 1α (HIF-1α), and vascular endothelial growth factor (VEGF), causing microvascular dysfunction. Dihydromyricetin (DMY) is a natural flavonoid small molecule antioxidant. However, it exhibits poor solubility in physiological environments, has a short half-life in vivo, and has low oral bioavailability. In this study, we present, for the first time, the synthesis of ultra-small Fe-DMY nano-coordinated polymer particles (Fe-DMY NCPs), formed by combining DMY with low-toxicity iron ions. In vitro and in vivo experiments confirm that Fe-DMY NCPs alleviate oxidative stress-induced damage to vascular endothelial cells by high glucose, scavenge excess ROS, and improve pathological features of DR, such as retinal vascular leakage and neovascularization. Mechanistic validation indicates that Fe-DMY NCPs can inhibit the activation of the Poldip2-Nox4-H2O2 signaling pathway and downregulate vital vascular function indicators such as VCAM-1, HIF-1α, and VEGF. These findings suggest that Fe-DMY NCPs could serve as a safe and effective antioxidant and microangio-protective agent, with the potential as a novel multimeric drug for DR therapy.

Advancing Cancer Therapy with Copper/Disulfiram Nanomedicines and Drug Delivery Systems

Disulfiram (DSF) is a thiocarbamate based drug that has been approved for treating alcoholism for over 60 years. Preclinical studies have shown that DSF has anticancer efficacy, and its supplementation with copper (CuII) significantly potentiates the efficacy of DSF. However, the results of clinical trials have not yielded promising results. The elucidation of the anticancer mechanisms of DSF/Cu (II) will be beneficial in repurposing DSF as a new treatment for certain types of cancer. DSF's anticancer mechanism is primarily due to its generating reactive oxygen species, inhibiting aldehyde dehydrogenase (ALDH) activity inhibition, and decreasing the levels of transcriptional proteins. DSF also shows inhibitory effects in cancer cell proliferation, the self-renewal of cancer stem cells (CSCs), angiogenesis, drug resistance, and suppresses cancer cell metastasis. This review also discusses current drug delivery strategies for DSF alone diethyldithocarbamate (DDC), Cu (II) and DSF/Cu (II), and the efficacious component Diethyldithiocarbamate-copper complex (CuET).

Preparation and anticancer actions of CuET-nanoparticles dispersed by bovine serum albumin

Diethyldithiocarbamate-copper complex (CuET) shows promising anticancer effect; nonetheless, preclinical evaluations of CuET are hindered due to poor solubility. We prepared bovine serum albumin (BSA)-dispersed CuET nanoparticles (CuET-NPs) to overcome the shortcoming. Results from a cell-free redox system demonstrated that CuET-NPs reacted with glutathione, leading to form hydroxyl radical. Glutathione-mediated production of hydroxyl radicals may help explain why CuET selectively kills drug-resistant cancer cells with higher levels of glutathione. CuET-NPs dispersed by autoxidation products of green tea epigallocatechin gallate (EGCG) also reacted with glutathione; however, the autoxidation products eradicated hydroxyl radicals; consequently, such CuET-NPs exhibited largely compromised cytotoxicity, suggesting that hydroxyl radical is a crucial mediator of CuET anticancer activity. In cancer cells, BSA-dispersed CuET-NPs exhibited cytotoxic activities equivalent to CuET and induced protein poly-ubiquitination. Moreover, the reported powerful inhibition of CuET on colony formation and migration of cancer cells could be replicated by CuET-NPs. These similarities demonstrate BSA-dispersed CuET-NPs is identical to CuET. Thus, we advanced to pilot toxicological and pharmacological evaluations. CuET-NPs caused hematologic toxicities in mice and induced protein poly-ubiquitination and apoptosis of cancer cells inoculated in mice at a defined pharmacological dose. Given high interest in CuET and its poor solubility, BSA-dispersed CuET-NPs pave the way for preclinical evaluations.

Hydroxyethyl starch stabilized copper-diethyldithiocarbamate nanocrystals for cancer therapy

Cancer stem cells (CSCs) have been recognized as the culprit for tumor progression, treatment resistance, metastasis, and recurrence while redox homeostasis represents the Achilles' Heel of CSCs. However, few drugs or formulations that are capable of elevating oxidative stress have achieved clinical success for eliminating CSCs. Here, we report hydroxyethyl starch stabilized copper-diethyldithiocarbamate nanoparticles (CuET@HES NPs), which conspicuously suppress CSCs not only in vitro but also in numerous tumor models in vivo. Furthermore, CuET@HES NPs effectively inhibit CSCs in fresh tumor tissues surgically excised from hepatocellular carcinoma patients. Mechanistically, we uncover that hydroxyethyl starch stabilized copper-diethyldithiocarbamate nanocrystals via copper‑oxygen coordination interactions, thereby promoting copper-diethyldithiocarbamate colloidal stability, cellular uptake, intracellular reactive oxygen species production, and CSCs apoptosis. As all components are widely used in clinics, CuET@HES NPs represent promising treatments for CSCs-rich solid malignancies and hold great clinical translational potentials. This study has critical implications for design of CSCs targeting nanomedicines.

Buffet-style Cu(II) for enhance disulfiram-based cancer therapy

Studies have shown that disulfiram (DSF) can combine with Cu²⁺ to form bis(N, N-diethyldithiocarbamate) copper(II) complex (CuET) as antitumor drugs. However, there is insufficient endogenous Cu²⁺ dose to eradicate cancer cells selectively. Inspired by the buffet, we use Cu²⁺ doped hollow zeolitic imidazolate framework nanoparticles (HZIF_Cu) as the carrier and equipped with DSF and indocyanine green (ICG) and targeted by folic acid (FA) (D&I@HZIF_Cu-FA) to enhance DSF-based cancer therapy. D&I@HZIF_Cu-FA could effectively supply Cu²⁺ by a buffet-style, assisting the "DSF-to-CuET" transformation in the tumor. Additionally, self-supply Cu²⁺ could convert H₂O₂ into ·OH by triggering a Fenton-like reaction for chemo-dynamic therapy, and ICG achieves photothermal therapy for tumors under laser irradiation. This work provides a buffet-style for Cu²⁺ to make DSF a strong candidate for cancer treatment by combining chemotherapy, chemo-dynamic therapy, and photothermal therapy and inspires more research about its applications in tumor therapy.

Hyaluronic Acid-Based Nanomaterials Applied to Cancer: Where Are We Now?

Cancer cells normally develop the ability to rewire or reprogram themselves to become resistant to treatments that were previously effective. Despite progress in understanding drug resistance, knowledge gaps remain regarding the underlying biological causes of drug resistance and the design of cancer treatments to overcome it. So, resistance acquisition remains a major problem in cancer treatment. Targeted therapeutics are considered the next generation of cancer therapy because they overcome many limitations of traditional treatments. Numerous tumor cells overexpress several receptors that have a high binding affinity for hyaluronic acid (HA), while they are poorly expressed in normal body cells. HA and its derivatives have the advantage of being biocompatible and biodegradable and may be conjugated with a variety of drugs and drug carriers for developing various formulations as anticancer therapies such as micelles, nanogels, and inorganic nanoparticles. Due to their stability in blood circulation and predictable delivery patterns, enhanced tumor-selective drug accumulation, and decreased toxicity to normal tissues, tumor-targeting nanomaterial-based drug delivery systems have been shown to represent an efficacious approach for the treatment of cancer. In this review, we aim to provide an overview of some in vitro and in vivo studies related to the potential of HA as a ligand to develop targeted nanovehicles for future biomedical applications in cancer treatment.

A dual gate-controlled intelligent nanoreactor enables collaborative precise treatment for cancer nanotherapy

Recently, disulfiram (DSF), approved by the FDA as an anti-alcoholic drug, has been proved as an effective antitumor drug after chelating with Cu²⁺. To overcome the shortage of intracellular Cu²⁺, we have constructed a dual gate-controlled intelligent nanoreactor (HA-DSF@HCuS@FePtMn, HDHF) via the ingenious combination of hollow copper sulfide (HCuS) nanoparticles, DSF and FePtMn nanocrystals. HDHF has a NIR-actuated gate and enzyme-actuated gate that could be opened in the hyaluronidase-abundant tumor microenvironment with NIR laser irradiation to trigger drug (DSF/FePtMn) release and synergistic therapy. Moreover, the FePtMn nanocrystals could continuously release Fe²⁺, which could catalyze H₂O₂ into highly cytotoxic hydroxyl radicals (˙OH), triggering chemodynamic therapy (CDT). When exposed to NIR laser, HCuS could collapse and release Cu²⁺, which could immediately chelate with DSF, forming the effective anticancer drug (Cu(DTC)₂) and enabling DSF-based chemotherapy. More importantly, the efficient photothermal therapy (PTT) effect of HCuS could accelerate the FePtMn-based CDT and the release of Cu²⁺/DSF, improving tumor treatment efficiency. Thus, this study represents a distinctive paradigm of a dual gate-controlled intelligent nanoreactor enabled PTT-augmented DSF-based chemotherapy and FePtMn-based CDT for cancer nanotherapy.

Disulfiram: A Food and Drug Administration-approved multifunctional role in synergistically drug delivery systems for tumor treatment

Disulfiram (DSF), a Food and Drug Administration (FDA)-approved drug for the treatment of alcoholism, has been found to have antitumor activity. DSF showed better antitumor efficiency when it was used in combination with certain antitumor drugs. DSF plays an important role in cancer treatment. It has been used as multidrug resistance (MDR) modulator to reverse MDR and can also combine with copper ions (Cu²⁺), which will produce copper diethyldithiocarbamate (Cu[DDC]₂) complex with antitumor activity. The synergistic targeted drug delivery for cancer treatment based on DSF, especially the combination with exogenous Cu²⁺ and its forms of administration, has attracted extensive attention in the biomedical field. In this review, we summarize these synergistic delivery systems, in the hope that they will contribute to the continuous optimization and development of more advanced drug delivery systems. Furthermore, we discuss the current limitation and future directions of DSF-based drug delivery systems in the field of tumor therapy. Hopefully, our work may inspire further innovation of DSF-based antitumor drug delivery systems.

Polymeric Nanosystems Applied for Metal-Based Drugs and Photosensitizers Delivery: The State of the Art and Recent Advancements

Nanotechnology-based approaches for targeting the delivery and controlled release of metal-based therapeutic agents have revealed significant potential as tools for enhancing the therapeutic effect of metal-based agents and minimizing their systemic toxicities. In this context, a series of polymer-based nanosized systems designed to physically load or covalently conjugate metal-based therapeutic agents have been remarkably improving their bioavailability and anticancer efficacy. Initially, the polymeric nanocarriers were applied for platinum-based chemotherapeutic agents resulting in some nanoformulations currently in clinical tests and even in medical applications. At present, these nanoassemblies have been slowly expanding for nonplatinum-containing metal-based chemotherapeutic agents. Interestingly, for metal-based photosensitizers (PS) applied in photodynamic therapy (PDT), especially for cancer treatment, strategies employing polymeric nanocarriers have been investigated for almost 30 years. In this review, we address the polymeric nanocarrier-assisted metal-based therapeutics agent delivery systems with a specific focus on non-platinum systems; we explore some biological and physicochemical aspects of the polymer–metallodrug assembly. Finally, we summarize some recent advances in polymeric nanosystems coupled with metal-based compounds that present potential for successful clinical applications as chemotherapeutic or photosensitizing agents. We hope this review can provide a fertile ground for the innovative design of polymeric nanosystems for targeting the delivery and controlled release of metal-containing therapeutic agents.

A Stimuli-Responsive Small-Molecule Metal-Carrying Prochelator: A Novel Prodrug Design Strategy for Metal Complexes

Selective activation of prodrugs is an important approach to reduce the side effects of disease treatment. We report a prodrug design concept for metal complexes, termed "metal-carrying prochelator", which can co-carry a metal ion and chelator within a single small-molecule compound and remain inert until it undergoes a specifically triggered intramolecular chelation to synthesize a bioactive metal complex in situ for targeted therapy. As a proof-of-concept, we designed a H₂ O₂ -responsive small-molecule prochelator, DPBD, based on the strong chelator diethyldithiocarbamate (DTC) and copper. DPBD can carry Cu²⁺ (DPBD-Cu) and respond to elevated H₂ O₂ levels in tumor cells by releasing DTC, which rapidly chelates Cu²⁺ from DPBD-Cu affording a DTC-copper complex with high cytotoxicity, realizing potent antitumor efficacy with low systemic toxicity. Thus, with its unique intramolecularly triggered activation mechanism, this concept based on a small-molecule metal-carrying prochelator can help in the prodrug design of metal complexes.

Two birds with one stone: Copper metal-organic framework as a carrier of disulfiram prodrug for cancer therapy

Disulfiram (DSF) has a copper (II)-potentiated anticancer activity in various cancers. Synchronous delivery of DSF and cupric ions to tumor tissues is challenging but holds great potential in improving antitumor outcomes and promoting clinical translation. Herein, we reported a disulfiram prodrug (DQ)-loaded and glucose oxidase (GOD) conjugated copper (II)-based nanoscale metal-organic framework (MOF), MPDG, for tumor-specific, enhanced chemo-chemodynamic therapy. Copper MOF, MOF-199, played a dual role of drug nanocarrier of DQ and copper ion reservoir for sufficient generation of copper (II) diethylthiocarbamate (Cu(DTC)₂), a complex of DSF and Cu²⁺. GOD improved the stability of Cu(II) nano-depot and enabled catalytic generation of H₂O₂ in response to high concentration of glucose in cancer cells. The catalytically generating and endogenous H₂O₂ boosted the activation of encapsulated H₂O₂-activatable prodrug DQ to generate highly cytotoxic Cu(CDTC)₂ in situ for tumor-specific chemotherapy. Meanwhile, the elevated H₂O₂ significantly augmented the production of OH for enhanced chemodynamic therapy. The self-activated amplified chemo-chemodynamic therapy nanosystem led to a significantly enhanced inhibition of 4T1 murine breast cancer cells (half inhibitory concentration reduced from 5 μg/mL to 0.8 μg/mL) in the presence of glucose. The in vivo study verified that MPDG showed the highest tumor inhibition rate of 86.2% and negligible toxicity to main organs. Overall, this study provides a novel disulfiram prodrug/Cu²⁺ co-delivery strategy for enhanced and selective cancer treatment.

Leveraging disulfiram to treat cancer: Mechanisms of action, delivery strategies, and treatment regimens

Disulfiram (DSF) has been used as an alcoholism drug for 70 years. Recently, it has attracted increasing attention owing to the distinguished anticancer activity, which can be further potentiated by the supplementation of Cu²⁺. Although encouraging anticancer results are obtained in lab, the clinical outcomes of oral DSF are not satisfactory, which urges an in-depth understanding of the underlying mechanisms, bottlenecks, and proposal of potential methods to address the dilemma. In this review, a critical summarization of various molecular biological anticancer mechanisms of DSF/Cu²⁺ is provided and the predicament of orally delivering DSF in clinical oncotherapy is explained by the metabolic barriers. We highlight the recent advances in the DSF/Cu²⁺ delivery strategies and the emerging treatment regimens for cancer treatment. Last but not the least, we summarize the clinical trials regarding DSF and make a prospect of DSF/Cu-based cancer therapy.

Nanoparticle-Hydrogel Systems Containing Platensimycin for Local Treatment of Methicillin-Resistant Staphylococcus aureus Infection

Skin and soft tissue infections require effective and sustained topical administration. Platensimycin (PTM) is a natural drug lead that targets bacterial fatty acid synthases and has a great potential to treat infections caused by methicillin-resistant Staphylococcus aureus (MRSA). To facilitate the use of PTM against local MRSA infections, we prepared polyacrylamide hydrogels containing polyamidoamine (PAMAM)/PTM nanoparticles (NP-gel(PTM)) for the controlled release of PTM. NP-gel(PTM) can continuously inhibit the growth of MRSA and its biofilm formation in simulated drug flow models in vitro. In situ implantation of NP-gel(PTM) could treat MRSA-infected subcutaneous soft tissues without toxicity. For MRSA-infected skin wounds, NP-gel(PTM) not only showed strong anti-MRSA activity but also accelerated more wound healing than the widely used antibiotic mupirocin. Collectively, PTM is expected to be used in this safe and effective NP-gel delivery platform for the treatment of local infections, which might help to alleviate the current antibiotic resistance crisis.

Copper Dithiocarbamates: Coordination Chemistry and Applications in Materials Science, Biosciences and Beyond

Copper dithiocarbamate complexes have been known for ca. 120 years and find relevance in biology and medicine, especially as anticancer agents and applications in materials science as a single-source precursor (SSPs) to nanoscale copper sulfides. Dithiocarbamates support Cu(I), Cu(II) and Cu(III) and show a rich and diverse coordination chemistry. Homoleptic [Cu(S2CNR2)2] are most common, being known for hundreds of substituents. All contain a Cu(II) centre, being either monomeric (distorted square planar) or dimeric (distorted trigonal bipyramidal) in the solid state, the latter being held together by intermolecular C···S interactions. Their d9 electronic configuration renders them paramagnetic and thus readily detected by electron paramagnetic resonance (EPR) spectroscopy. Reaction with a range of oxidants affords d8 Cu(III) complexes, [Cu(S2CNR2)2][X], in which copper remains in a square-planar geometry, but Cu–S bonds shorten by ca. 0.1 Å. These show a wide range of different structural motifs in the solid-state, varying with changes in anion and dithiocarbamate substituents. Cu(I) complexes, [Cu(S2CNR2)2]−, are (briefly) accessible in an electrochemical cell, and the only stable example is recently reported [Cu(S2CNH2)2][NH4]·H2O. Others readily lose a dithiocarbamate and the d10 centres can either be trapped with other coordinating ligands, especially phosphines, or form clusters with tetrahedral [Cu(μ3-S2CNR2)]4 being most common. Over the past decade, a wide range of Cu(I) dithiocarbamate clusters have been prepared and structurally characterised with nuclearities of 3–28, especially exciting being those with interstitial hydride and/or acetylide co-ligands. A range of mixed-valence Cu(I)–Cu(II) and Cu(II)–Cu(III) complexes are known, many of which show novel physical properties, and one Cu(I)–Cu(II)–Cu(III) species has been reported. Copper dithiocarbamates have been widely used as SSPs to nanoscale copper sulfides, allowing control over the phase, particle size and morphology of nanomaterials, and thus giving access to materials with tuneable physical properties. The identification of copper in a range of neurological diseases and the use of disulfiram as a drug for over 50 years makes understanding of the biological formation and action of [Cu(S2CNEt2)2] especially important. Furthermore, the finding that it and related Cu(II) dithiocarbamates are active anticancer agents has pushed them to the fore in studies of metal-based biomedicines.

Targeting Ubiquitin-Proteasome System With Copper Complexes for Cancer Therapy

Characterizing mechanisms of protein homeostasis, a process of balancing between protein synthesis and protein degradation, is important for understanding the potential causes of human diseases. The ubiquitin–proteasome system (UPS) is a well-studied mechanism of protein catabolism, which is responsible for eliminating misfolded, damaged, or aging proteins, thereby maintaining quality and quantity of cellular proteins. The UPS is composed of multiple components, including a series of enzymes (E1, E2, E3, and deubiquitinase [DUB]) and 26S proteasome (19S regulatory particles + 20S core particle). An impaired UPS pathway is involved in multiple diseases, including cancer. Several proteasome inhibitors, such as bortezomib, carfilzomib, and ixazomib, are approved to treat patients with certain cancers. However, their applications are limited by side effects, drug resistance, and drug–drug interactions observed in their clinical processes. To overcome these shortcomings, alternative UPS inhibitors have been searched for in many fields. Copper complexes (e.g., CuET, CuHQ, CuCQ, CuPDTC, CuPT, and CuHK) are found to be able to inhibit a core component of the UPS machinery, such as 20S proteasome, 19S DUBs, and NPLOC4/NPL4 complex, and are proposed to be one class of metal-based anticancer drugs. In this review, we will summarize functions and applications of copper complexes in a concise perspective, with a focus on connections between the UPS and cancer.

One-for-all intelligent core-shell nanoparticles for tumor-specific photothermal-chemodynamic synergistic therapy

Reasonable management of the one-for-all nanoplatform can facilitate improved cancer therapy. Here, the metal-organic frameworks (MOFs) based on iron(iii) carboxylate material (MIL-101-NH₂) were in situ decorated on stabilized polydopamine nanoparticles (PDANPs), which subsequently loaded glucose oxidase (GOx) via hyaluronic acid (HA) coating to structure the one-for-all intelligent core-shell nanoparticles (HG-MIL@PDANPs). Because of the inner PDANPs, the HG-MIL@PDANPs could realize near-infrared (NIR)-controllable site-specific photothermal therapy (PTT). Additionally, the core-shell nanoparticles exhibited a pH-triggered and NIR-reinforced release of Fe³⁺ and GOx owing to the controllable degradation of the outer shell. Hydroxyl radicals (˙OH) were produced for chemodynamic therapy (CDT) employing the Fe²⁺-driven Fenton reaction, which could be greatly promoted by Fe³⁺-involved glutathione (GSH) depletion and GOx-catalyzed acidity recovery and H₂O₂ self-sufficiency. Moreover, the HA ligand could enhance the tumor accumulation of the HG-MIL@PDANPs through the long blood circulation time and CD44-targeted cell recognition. The ingenious integration of PTT and CDT in one fully equipped system presented excellent synergistic antitumor efficiency in vitro and in vivo with favorable biosafety. The one-for-all intelligent core-shell nanoparticles with CD44 targeting provide a new avenue for engineering on-demand tumor-specific therapy.