New roles for copper metabolism in cell proliferation, signaling, and disease

STEAP4 with copper reductase activity suppresses tumorigenesis by regulating the cell cycle in hepatocellular carcinoma cells

BACKGROUND

Abnormal expression of six-transmembrane epithelial antigen of prostate 4 (STEAP4) has been implicated in the carcinogenesis of hepatocellular carcinoma (HCC). However, the biological role and regulatory mechanisms of STEAP4 in HCC remain unclear.

METHODS AND RESULTS

Here, we analyzed STEAP4 expression levels and differentially expressed genes (DEGs) between STEAP4 high- and low-expression groups using multiple databases. Proliferation assays, 5-ethynyl-2'-deoxyuridine (EdU) assays, propidium iodide (PI) flow cytometry, and colony formation assays were conducted to assess the effects of STEAP4 on HCC cell proliferation, cell cycle progression, and clonogenic capacity. STEAP4 was downregulated in HCC tumor tissues, with lower expression associated with poorer overall survival (OS) and disease-free survival (DFS) in patients. Functional network analysis suggested that STEAP4 regulates cell cycle signaling, with tumor sections showing a negative correlation between STEAP4 and cell cycle proteins. Overexpression of STEAP4, combined with non-cytotoxic copper exposure in the HepG2 cell line, reduced proliferation and clonogenicity, induced cell cycle arrest, and downregulated the mRNA and protein levels of cell cycle-regulating genes. A predictive model based on STEAP4 and cell cycle gene demonstrated prognostic value in HCC patients.

CONCLUSIONS

Our results lay a foundation for further study of the cell cycle regulatory role of STEAP4 with Cu2+ reductase activity in HCC, indicating that STEAP4 may be a promising therapeutic target for HCC.

Involvement of copper in cell death and cancer

Copper (cu) is an essential micronutrient required for numerous metabolic processes. It plays a crucial role in cellular respiration by participating in the electron transport chain and facilitating numerous biological reactions. Various diseases, including cancer, demonstrate localized elevation of copper levels and/or alterations in the overall distribution of copper. Modulating local or systemic copper levels as a novel therapeutic approach for treating and ameliorating diseases has emerged as a prominent trend in disease management, particularly in the realm of cancer therapy, which is currently under investigation. The objective of this review is to offer a thorough examination of copper metabolism in both physiological and pathological contexts. Specifically, it delves into how copper ions can effectively target and stimulate tumor cell death via the process known as cuproptosis in cancer patients. Furthermore, this review explores the utilization of three categories of anticancer medications (copper ion carriers, copper complexes, and copper chelating agents) pertaining to copper metabolism within the realm of cancer therapy, elucidating on the distinct mechanisms through which they exert their effects.

Chaperone-Derived Copper(I)-Binding Peptide Nanofibers Disrupt Copper Homeostasis in Cancer Cells

Copper (Cu) is a transition metal that plays crucial roles in cellular metabolism. Cu+ homeostasis is upregulated in many cancers and contributes to tumorigenesis. However, therapeutic strategies to target Cu+ homeostasis in cancer cells are rarely explored because small molecule Cu+ chelators have poor binding affinity in comparison to the intracellular Cu+ chaperones, enzymes, or ligands. To address this challenge, we introduce a Cu+ chaperone-inspired supramolecular approach to disrupt Cu+ homeostasis in cancer cells that induces programmed cell death. The Nap-FFMTCGGCR peptide self-assembles into nanofibers inside cancer cells with high binding affinity and selectivity for Cu+ due to the presence of the unique MTCGGC motif, which is conserved in intracellular Cu+ chaperones. Nap-FFMTCGGCR exhibits cytotoxicity towards triple negative breast cancer cells (MDA-MB-231), impairs the activity of Cu+ dependent co-chaperone super oxide dismutase1 (SOD1), and induces oxidative stress. In contrast, Nap-FFMTCGGCR has minimal impact on normal HEK 293T cells. Control peptides show that the self-assembly and Cu+ binding must work in synergy to successfully disrupt Cu+ homeostasis. We show that assembly-enhanced affinity for metal ions opens new therapeutic strategies to address disease-relevant metal ion homeostasis.

Elements in trace amount with a significant role in human physiology: a tumor pathophysiological and diagnostic aspects

Cancer has a devastating impact globally regardless of gender, age, and community, which continues its severity to the population due to the lack of efficient strategy for the cancer diagnosis and treatment. According to the World Health Organisation report, one out of six people dies due to this deadly cancer and we need effective strategies to regulate it. In this context, trace element has a very hidden and unexplored role and require more attention from investigators. The variation in concentration of trace elements was observed during comparative studies on a cancer patient and a healthy person making them an effective target for cancer regulation. The percentage of trace elements present in the human body depends on environmental exposure, food habits, and habitats and could be instrumental in the early diagnosis of cancer. In this review, we have conducted inclusive analytics on trace elements associated with the various types of cancers and explored the several methods involved in their analysis. Further, intricacies in the correlation of trace elements with prominent cancers like prostate cancer, breast cancer, and leukaemia are represented in this review. This comprehensive information on trace elements proposes their role during cancer and as biomarkers in cancer diagnosis.

Connecting the changing trace elements spectrum and survival in sarcoma: a pilot study

OBJECTIVES

While some metals have been reported as carcinogens or potential carcinogens, only few modern-standard datasets including a large number of elements are available. The present analysis established a first trace elements spectrum by relating the concentration of metals and trace elements in the serum of sarcoma patients with survival data.

METHODS

Patients with sarcoma and controls were retrospectively selected from the International Sarcoma Kindred Study database (ISKS). As part of the ISKS study, blood samples were prospectively collected at the Leon Bérard Cancer Center from February 2012 to July 2019. Stable specimens and copper isotopes (65Cu/63Cu) were analyzed using Triple Quadrupole Inductively Coupled Plasma Mass Spectrometer (ICP-MS) and the Multicollector MC-ICP-MS Nu Plasma HR 500. Wilcoxon rank sum test, log-rank test, and multivariate Cox regression models were used for statistics.

RESULTS

In total, 151 patients and 59 healthy controls were included. At the time of blood sample collection, 62% of patients had locally advanced or metastatic disease. Copper (Cu), copper/zinc (Cu/Zn) and potassium/rubidium (K/Rb) ratio were significantly higher in patients compared to controls and were also significantly higher in patients with advanced compared to early-stage sarcoma. Whereas S and Se were significantly correlated in patients, no correlation was observed in controls. Importantly, levels of K, Rb, Se, Fe, P, Si, S, δ65Cu, Cu, S/Se and Cu/Zn ratio were independently associated with overall survival.

CONCLUSIONS

These results depict the metallomic spectrum in sarcoma and highlight substantial variation associated with survival, enhancing our understanding of sarcoma's biology.

Synthesis of biscarbazole derivative, detection of the "on-off" sensor property of Cu2+ by fluorimetry, and anti-cancer evaluation

Biscarbazole derivative probe (6) (Z)-2-(3-(((9-heptyl-9H-carbazol-3-yl)methylene)amino)-9H-carbazol-9-yl)ethan-1-ol containing an imine group, which is a sensitive and selective fluorescence chemosensor, was designed and synthesized for the effective evaluation of Cu2+ metal ion levels. The synthesized compounds were characterized using 1H NMR, 13C NMR, FT-IR, and MALDI-TOF MS (for compound 6) spectroscopic data. The interaction model between probe 6 and Cu2+ was determined by combining fluorescence methods, 1H NMR titration, Job's plot, and theoretical calculations. For probe 6, the fluorogenic recognition of Cu2+ was investigated by fluorescence spectroscopy, and the optical changes caused by Cu2+ ions were carried out in ACN/H2O (50:50) solution at pH 7.0. Fluorescence probe 6 was found to "turn-off" its fluorescence in the presence of paramagnetic Cu2+ ions. Probe 6 was determined to have a rapid response within 40s and showed a fluorescence response to Cu2+ with a low detection limit of 0.16 μM. Additionally, in vitro anticancer activity and cell imaging studies of probe 6 against the prostate cell line (PC-3) were performed.

A Rhodamine-coumarin Triazole Conjugate as a Fluorescent Chemodosimeter for Cu(II) Detection and its Application in Live Cell Bioimaging

A rhodamine-triazole fluorescent probe bearing a coumarin moiety RTC was synthesized using the Cu(I)-catalyzed click reaction. The rhodamine-triazole conjugate was highly selective to Cu2+ among other metal ions, including Ca2+, Co2+, Cu2+, Cd2+, Mg2+, Fe2+, Fe3+, Hg2+, Zn2+, Ni2+, Pd2+ and Pb2+ in physiological conditions. Upon the addition of Cu2+, the colorless RTC solution turned pink and exhibited a significant fluorescence emission centered at 578 nm. The binding of Cu2+ induced a hydrolysis reaction, leading to a release of the coumarin unit from the rhodamine probe, as confirmed by mass spectrometric data. From the fluorescence titration, the detection limit of RTC for Cu2+ was determined to be 21 nM (1.3 ppb). The sensor was responsive to Cu2+ in a wide pH range and successfully applied to monitor Cu2+ in HEK293T cells by confocal fluorescence imaging.

Claudin-12: guardian of the tissue barrier or friend of tumor cells

Tight junctions (TJs) are an important component of cellular connectivity. Claudin family proteins, as a constituent of TJs, determine their barrier properties, cell polarity and paracellular permeability. Claudin-12 is an atypical member of the claudin family, as it belongs to the group of non-classical claudins that lack a PDZ-binding domain. It has been shown that claudin-12 is involved in paracellular Ca2+ transients and it is present in normal and hyperplastic tissues in addition to neoplastic tissues. Dysregulation of claudin-12 expression has been reported in various cancers, suggesting that this protein may play an important role in cancer cell migration, invasion, and metastasis. Some studies have shown that claudin-12 gene functions as a tumor suppressor, but others have reported that overexpression of claudin-12 significantly increases the metastatic properties of various tumor cells. Investigating this dual role of claudin-12 is of utmost importance and should therefore be studied in detail. The aim of this review is to provide an overview of the information available to date on claudin-12, including its structure, expression in various tissues and substances that may affect it, with a final focus on its role in cancer.

Facile Green Gamma Irradiation of Water Hyacinth Derived-Fluorescent Carbon Dots Functionalized Thiol Moiety for Metal Ion Detection

Fluorescent sensor-based carbon dots (CDs) have significantly developed for sensing metal ions because of their great physical and optical properties, including tunable fluorescence emission, high fluorescence quantum yield, high sensitivity, non-toxicity, and biocompatibility. In this research, a green synthetic approach via simple gamma irradiation for the carbon dot synthesis from water hyacinth was developed since water hyacinth has been classified as an invasive aquatic plant containing cellulose, hemicellulose, and lignin. The thiol moiety (SH) was further functionalized on the surface functional groups of CDs as the "turn-off" fluorescent sensor for metal ion detection. Fluorescence emission displayed a red shift from 451 to 548 nm when excited between 240 and 500 nm. The quantum yield of CDs-SH was elucidated to be 13%, with strong blue fluorescence emission under ultraviolet irridiation (365 nm), high photostability and no photobleaching. The limit of detection was determined at micromolar levels for Hg2+, Cu2+, and Fe3+. CDs-SH could be a real-time monitoring sensor for Hg2+ and Cu2+ as fluorescence quenching was observed within 2 min. Furthermore, paper test-strip based CDs-SH could be applied to detect these metal ions.

Cuproptosis in cancer: biological implications and therapeutic opportunities

Cuproptosis, a newly identified copper (Cu)-dependent form of cell death, stands out due to its distinct mechanism that sets it apart from other known cell death pathways. The molecular underpinnings of cuproptosis involve the binding of Cu to lipoylated enzymes in the tricarboxylic acid cycle. This interaction triggers enzyme aggregation and proteotoxic stress, culminating in cell death. The specific mechanism of cuproptosis has yet to be fully elucidated. This newly recognized form of cell death has sparked numerous investigations into its role in tumorigenesis and cancer therapy. In this review, we summarized the current knowledge on Cu metabolism and its link to cancer. Furthermore, we delineated the molecular mechanisms of cuproptosis and summarized the roles of cuproptosis-related genes in cancer. Finally, we offered a comprehensive discussion of the most recent advancements in Cu ionophores and nanoparticle delivery systems that utilize cuproptosis as a cutting-edge strategy for cancer treatment.

Ferroptosis and cuproptposis in kidney Diseases: dysfunction of cell metabolism

Metal ions play an important role in living organisms and are involved in essential physiological activities. However, the overload state of ions can cause excess free radicals, cell damage, and even cell death. Ferroptosis and cuproptosis are specific forms of cell death that are distinct from apoptosis, necroptosis, and other regulated cell death. These unique modalities of cell death, dependent on iron and copper, are regulated by multiple cellular metabolic pathways, including steady-state metal redox treatment mitochondrial activity of lipid, amino acid and glucose metabolism, and various signaling pathways associated with disease. Although the mechanisms of ferroptosis and cuproptosis are not yet fully understood, there is no doubt that ion overload plays a crucial act in these metal-dependent cell deaths. In this review, we discussed the core roles of ion overload in ferroptosis and cuproptosis, the association between metabolism imbalance and ferroptosis and cuproptosis, the extract the diseases caused by ion overload and current treatment modalities.

Effects of dietary copper intake on blood lipids in women of childbearing age and the potential role of gut microbiota

Background

Copper (Cu) is a vital trace element involved in numerous physiological processes, including glycolysis and lipid metabolism. Imbalances in Cu homeostasis can contribute to various diseases. However, current research on the impact of Cu on lipid metabolism has yielded inconsistent findings. Moreover, studies investigating the effects of dietary Cu intake on blood lipids among women of childbearing age are rare. Understanding of this relationship could enhance lipid management, given that most women obtain Cu through their diet. Additionally, the gut microbiota may play a role in this process. This study aims to investigate the effects of dietary Cu intake on blood lipids in women of childbearing age and to analyze the role of gut microbiota in this process.

Methods

This study utilized data from the National Health and Nutrition Examination Survey (NHANES) to conduct a preliminary analysis of the correlation between dietary Cu levels and blood lipid indicators in women of childbearing age. Subsequently, an on-site research was conducted to further investigate this relationship, followed by animal experiments to verify the effect of different Cu doses on blood lipid levels. Multiple linear regression models, ANOVA, XGBOOST were employed to analyze the impact of Cu on blood lipids and the role of intestinal microbiota in this process.

Results

In the population study, the NHANES results were consistent with on-site findings. The TG, and TC levels in women with childbearing were increased with higher dietary Cu intake. Animal experiments have shown that as Cu intake increases, TC levels increase. Furthermore, when the Cu intake reached 8 mg/day (the recommended dietary Cu intake limit of China, RDI), the TG levels in the research animals decrease, alongside a reduction in the abundance of Weissella cibaria (probiotics related to lipid metabolism), and the levels of LPS and IL-6 increase.

Conclusion

The blood lipid levels of women of childbearing age increase with higher dietary Cu intake. RDI of 8 mg/day for women of childbearing age in China may need to be appropriately reduced. Regulating the gut microbiota, especially by increasing the abundance of Weissella cibaria may be an effective intervention for blood lipids.

Evidence of direct interaction between cisplatin and the caspase-cleaved prostate apoptosis response-4 tumor suppressor

Prostate apoptosis response-4 (Par-4) tumor suppressor protein has gained attention as a potential therapeutic target owing to its unique ability to selectively induce apoptosis in cancer cells, sensitize them to chemotherapy and radiotherapy, and mitigate drug resistance. It has recently been reported that Par-4 interacts synergistically with cisplatin, a widely used anticancer drug. However, the mechanistic details underlying this relationship remain elusive. In this investigation, we employed an array of biophysical techniques, including circular dichroism spectroscopy, dynamic light scattering, and UV-vis absorption spectroscopy, to characterize the interaction between the active caspase-cleaved Par-4 (cl-Par-4) fragment and cisplatin. Additionally, elemental analysis was conducted to quantitatively assess the binding of cisplatin to the protein, utilizing inductively coupled plasma-optical emission spectroscopy and atomic absorption spectroscopy. Our findings provide evidence of direct interaction between cl-Par-4 and cisplatin, and reveal a binding stoichiometry of 1:1. This result provides insights that could be useful in enhancing the efficacy of cisplatin-based and tumor suppressor-based cancer therapies.

Copper-gallate metal-organic framework encapsulated multifunctional konjac glucomannan microneedles patches for promoting wound healing

An ideal chronic wound dressing needs to have some properties, such as antibacterial, antioxidant, regulating macrophage polarization and promoting angiogenesis. This work presents a microneedle patch fabricated from oxidized konjac glucomannan (OKGM-MNs), in which Copper-gallate metal-organic framework (CuGA-MOF) is encapsulated for wound healing (denoted as CuGA-MOF@OKGM-MNs). CuGA-MOF is composed of Cu2+ and gallic acid (GA), which are released through microneedles in the deep layer of the dermis. The released Cu2+ is able to act as an antibacterial agent and promote angiogenesis, while GA as a reactive oxygen species scavenger displays antioxidant activity. More attractively, the material OKGM used to prepare the microneedle patch is not only a drug carrier but also plays a role in promoting macrophage polarization M2 phenotype. In vitro experiments showed that CuGA-MOF@OKGM-MNs had good antibacterial and antioxidant properties. The therapeutic effect on wound healing has been confirmed in full-thickness skin wounds of diabetes mice models, which showed that the wound could be completely healed within 21 days under the treatment of CuGA-MOF@OKGM-MNs, and the healing effect was better than other groups. These indicated that the proposed CuGA-MOF@OKGM-MNs could be applicable in the treatment of clinical wound healing.

An Insight into the Effect of Schiff Base and their d and f Block Metal Complexes on Various Cancer Cell Lines as Anticancer Agents: A Review

Over the last few decades, an alarming rise in the percentage of individuals with cancer and those with multi-resistant illnesses has forced researchers to explore possibilities for novel therapeutic approaches. Numerous medications currently exist to treat various disorders, and the development of small molecules as anticancer agents has considerable potential. However, the widespread prevalence of resistance to multiple drugs in cancer indicates that it is necessary to discover novel and promising compounds with ideal characteristics that could overcome the multidrug resistance issue. The utilisation of metallo-drugs has served as a productive anticancer chemotherapeutic method, and this approach may be implemented for combating multi-resistant tumours more successfully. Schiff bases have been receiving a lot of attention as a group of compounds due to their adaptable metal chelating abilities, innate biologic properties, and versatility to tweak the structure to optimise it for a specific biological purpose. The biological relevance of Schiff base and related complexes, notably their anticancer effects, has increased in their popularity as bio-inorganic chemistry has progressed. As a result of learning about Schiff bases antitumor efficacy against multiple cancer cell lines and their complexes, researchers are motivated to develop novel, side-effect-free anticancer treatments. According to study reports from the past ten years, we are still seeking a powerful anticancer contender. This study highlights the potential of Schiff bases, a broad class of chemical molecules, as potent anticancer agents. In combination with other anticancer strategies, they enhance the efficacy of treatment by elevating the cytotoxicity of chemotherapy, surmounting drug resistance, and promoting targeted therapy. Schiff bases also cause cancer cell DNA repair, improve immunotherapy, prevent angiogenesis, cause apoptosis, and lessen the side effects of chemotherapy. The present review explores the development of potential Schiff base and their d and f block metal complexes as anticancer agents against various cancer cell lines.

Copper in Cancer: from transition metal to potential target

In recent years, with the continuous in-depth exploration of the molecular mechanisms of tumorigenesis, numerous potential new targets for cancer treatment have been identified, some of which have been further developed in clinical practice and have produced positive outcomes. Notably, researchers' initial motivation for studying copper metabolism in cancer stems from the fact that copper is a necessary trace element for organisms and is closely connected to body growth and metabolism. Moreover, over the past few decades, considerable progress has been made in understanding the molecular processes and correlations between copper and cancer. Certain achievements have been made in the development and use of relevant clinical medications. The concept of "cuproptosis," a novel concept that differs from previous forms of cell death, was first proposed by a group of scientists last year, offering fresh perspectives on the targeting capabilities of copper in the treatment of cancer. In this review, we introduced the fundamental physiological functions of copper, the key components of copper metabolism, and a summary of the current research contributions on the connection between copper and cancer. In addition, the development of new copper-based nanomaterials and their associated mechanisms of action are discussed. Finally, we described how the susceptibility of cancer cells to this metallic nutrition could be leveraged to further improve the existing cancer treatment paradigm in the new setting.

Choline metabolism and its implications in cancer

Choline, a quintessential quaternary ammonium compound, plays a cardinal role in several pivotal biological mechanisms, chiefly in safeguarding cell membrane integrity, orchestrating methylation reactions, and synthesizing vital neurotransmitters. This systematic review meticulously dissects the complex interplay between choline metabolism and its profound implications in oncology. The exposition is stratified into three salient dimensions: Initially, we delve into the intricacies of choline metabolism, accentuating its indispensability in cellular physiology, the enzymatic labyrinth governing its flux, and the pivotal cellular import mechanisms. Subsequently, we elucidate the contemporary comprehension of choline metabolism in the cancer paradigm, traversing its influence from inception to the intricate metamorphosis during oncogenic progression, further compounded by dysregulated enzyme activities and aberrant signaling cascades. Conclusively, we illuminate the burgeoning potential of choline-centric metabolic imaging modalities, notably magnetic resonance spectroscopy (MRS) and positron emission tomography (PET), as avant-garde tools for cancer diagnostics and therapeutic trajectory monitoring. Synoptically, the nuanced perturbations in choline metabolism in neoplastic entities unfurl critical insights, potentially heralding paradigm shifts in diagnostic and therapeutic oncological stratagems. A deeper foray into this realm is anticipated to fortify our molecular understanding and refine intervention modalities in cancer theranostics.

Microenvironment-responsive Cu-phenolic networks coated nanofibrous dressing with timely macrophage phenotype transition for chronic MRSA infected wound healing

Methicillin-resistant Staphylococcus aureus (MRSA) infection is a pressing clinical issue that impedes wound healing. Pro-inflammatory M1 macrophages is required to clear bacteria and recruit various cell types during the initial phase of wound healing, but timing of this process is crucial. Herein, a microenvironment-responsive nanofibrous dressing capable of timely macrophage phenotype transition in vivo is constructed by coating copper ions (Cu2+)-polydopamine (PDA) networks on poly (ε-caprolactone) fiber (PCL-fiber) membrane. During the initial post-implantation period, the nanofibrous dressing show pH-sensitive Cu2+ release in the acidic infection microenvironment. The release Cu2+ have a direct killing effect on MRSA, and promote the proinflammatory M1 phenotype of macrophages to enhance the antibacterial macrophage response. Later, PDA to become a reactive oxygen species (ROS) scavenger when in microenvironments with elevated ROS levels, which conferred the dressing with an immunomodulatory activity that convert M1 macrophages into M2 macrophages. In vivo examination in an MRSA infected full-thickness skin wounds of rat model demonstrates that this dressing significantly facilitated infection eradication and wound healing through modulating local inflammatory phenotype. Overall, this study offers a simple and effective approach for timely manipulation of inflammation progression to promote infected wound healing.

Copper homeostasis and cuproptosis in tumor pathogenesis and therapeutic strategies

Copper is an indispensable micronutrient for the development and replication of all eukaryotes, and its redox properties are both harmful and beneficial to cells. An imbalance in copper homeostasis is thought to be involved in carcinogenesis. Importantly, cancer cell proliferation, angiogenesis, and metastasis cannot be separated from the effects of copper. Cuproposis is a copper-dependent form of cell death that differs from other existing modalities of regulatory cell death. The role of cuproptosis in the pathogenesis of the nervous and cardiovascular systems has been widely studied; however, its impact on malignant tumors is yet to be fully understood from a clinical perspective. Exploring signaling pathways related to cuproptosis will undoubtedly provide a new perspective for the development of anti-tumor drugs in the future. Here, we systematically review the systemic and cellular metabolic processes of copper and the regulatory mechanisms of cuproptosis in cancer. In addition, we discuss the possibility of targeting copper ion drugs to prolong the survival of cancer patients, with an emphasis on the most representative copper ionophores and chelators. We suggest that attention should be paid to the potential value of copper in the treatment of specific cancers.

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.

Root development in Leucaena leucocephala (Lam.) de Wit enhances copper accumulation

Potentially toxic elements (PTE) in soil like copper (Cu) have been common in agricultural and mining areas worldwide. The sustainable remediation of these areas has been shown to have high socio-environmental relevance and phytoremediation is one of the green technologies to be considered. The challenge is to identify species that are tolerant to PTE, and to assess their phytoremediation potential. The objective of this study was to evaluate the physiological response of Leucaena leucocephala (Lam.) de Wit and to determine the species tolerance and phytoremediation potential to concentrations of Cu in the soil (100, 200, 300, 400 and 500 mg/dm3). The photosynthetic rate was not affected, while the content of chlorophylls decreased as Cu concentrations increased. There was an increased in stomatal conductance and water use efficiency from the treatment of 300. The root biomass and the length were bigger than the shoots, in the treatments above 300. Cu accumulation was greater in the roots than in the shoot of the plants, thus, the Cu translocation index to the shoot was lower. The ability to absorb and accumulate, mainly, Cu in the roots, allowed the development and growth of plants, since the parameters of photosynthesis and biomass accumulation were not affected by the Cu excess. This accumulation in the roots is characterized as a strategy for the phytostabilization of Cu. Therefore, L. leucocephala is tolerant to the Cu concentrations evaluated and has a potential phytoremediation of Cu in the soil.

Copper in cancer: from limiting nutrient to therapeutic target

As an essential nutrient, copper's redox properties are both beneficial and toxic to cells. Therefore, leveraging the characteristics of copper-dependent diseases or using copper toxicity to treat copper-sensitive diseases may offer new strategies for specific disease treatments. In particular, copper concentration is typically higher in cancer cells, making copper a critical limiting nutrient for cancer cell growth and proliferation. Hence, intervening in copper metabolism specific to cancer cells may become a potential tumor treatment strategy, directly impacting tumor growth and metastasis. In this review, we discuss the metabolism of copper in the body and summarize research progress on the role of copper in promoting tumor cell growth or inducing programmed cell death in tumor cells. Additionally, we elucidate the role of copper-related drugs in cancer treatment, intending to provide new perspectives for cancer treatment.

Hot and heavy: Responses of ragworms (Hediste diversicolor) to copper-spiked sediments and elevated temperature

Sediment contamination and seawater warming are two major stressors to macrobenthos in estuaries. However, little is known about their combined effects on infaunal organisms. Here we investigated the responses of an estuarine polychaete Hediste diversicolor to metal-contaminated sediment and increased temperature. Ragworms were exposed to sediments spiked with 10 and 20 mg kg^-1 of copper at 12 and 20 °C for three weeks. No considerable changes were observed in the expression of genes related to copper homeostasis and in the accumulation of oxidative stress damage. Dicarbonyl stress was attenuated by warming exposure. Whole-body energy reserves in the form of carbohydrates, lipids and proteins were little affected, but the energy consumption rate increased with copper exposure and elevated temperature indicating higher basal maintenance costs of ragworms. The combined effects of copper and warming exposures were mostly additive, with copper being a weak stressor and warming a more potent stressor. These results were replicable, as confirmed by two independent experiments of similar settings conducted at two different months of the year. This study suggests the higher sensitivity of energy-related biomarkers and the need to search for more conserved molecular markers of metal exposure in H. diversicolor.

Loss of OPT3 function decreases phloem copper levels and impairs crosstalk between copper and iron homeostasis and shoot-to-root signaling in Arabidopsis thaliana

Copper (Cu) and iron (Fe) are essential micronutrients that are toxic when accumulating in excess in cells. Thus, their uptake by roots is tightly regulated. While plants sense and respond to local Cu availability, the systemic regulation of Cu uptake has not been documented in contrast to local and systemic control of Fe uptake. Fe abundance in the phloem has been suggested to act systemically, regulating the expression of Fe uptake genes in roots. Consistently, shoot-to-root Fe signaling is disrupted in Arabidopsis thaliana mutants lacking the phloem companion cell-localized Fe transporter, OLIGOPEPTIDE TRANSPORTER 3 (AtOPT3). We report that AtOPT3 also transports Cu in heterologous systems and contributes to its delivery from sources to sinks in planta. The opt3 mutant contained less Cu in the phloem, was sensitive to Cu deficiency and mounted a transcriptional Cu deficiency response in roots and young leaves. Feeding the opt3 mutant and Cu- or Fe-deficient wild-type seedlings with Cu or Fe via the phloem in leaves downregulated the expression of both Cu- and Fe-deficiency marker genes in roots. These data suggest the existence of shoot-to-root Cu signaling, highlight the complexity of Cu/Fe interactions, and the role of AtOPT3 in fine-tuning root transcriptional responses to the plant Cu and Fe needs.

Rescue effect of curcumin against copper toxicity

Turmeric has long been used not only as an indispensable part of Asian cuisine but as a medicinal herb for dressing wounds, bites, burns, treating eye infections and acne. Curcuminoids are the active substances and their synthetic derivatives (i.e. diacetylcurcumin (DAC) and metal-curcumin complexes) possess an incredibly wide range of medicinal properties that encompass chelation capacity for multiple heavy metals, antioxidant activity, anti-inflammatory properties, cytotoxicity against cancerous cells, antiviral and antibacterial effects, antihypertensive and insulin sensitizing role, and regulatory role on apoptosis. The aforementioned properties have put curcumin on spotlight as a potential treatment for ailments such as, hepatic diseases, neurodegenerative diseases, metabolic syndrome, dyslipidemia, cardiovascular disease, auto-immune diseases, malignancies and conditions associated with metal overload. Copper is essential for major biological functions, however, an excess causes chronic ailments including neurodegenerative disorders. The fascinating approach of curcumin could alleviate such effect by forming a complex. Thus, this review aims to present available data on the effect of copper-curcumin interaction in various in vitro, ex-vivo in vivo, and clinical studies.

Pan-cancer analyses reveal molecular and clinical characteristics of cuproptosis regulators

Imbalance in copper homeostasis can be lethal. A recent study found that excess copper induces cell death in a way that has never been characterized before, which is dependent on mitochondrial stress and is referred to as "cuproptosis." The role of cuproptosis in tumors has not yet been elucidated. In this study, we revealed the complex and important roles of cuproptosis regulators and cuproptosis activity in tumors via a comprehensive analysis of multiomics data from more than 10,000 samples of 33 tumor types. We found that the cyclin-dependent kinase inhibitor 2A is the most frequently altered cuproptosis regulator, and the cuproptosis regulator expression is dysregulated in various tumors. Additionally, we developed a cuproptosis activity score to reflect the overall cuproptosis level. On the basis of the expression levels of cuproptosis regulators, tumors can be divided into two clusters with different cuproptosis activities and survival outcomes. Importantly, cuproptosis activity was found to be associated with the prognosis of multiple tumors and multiple tumor-related pathways, including fatty acid metabolism and remodeling of the tumor microenvironment. Furthermore, cuproptosis increased the sensitivity to multiple drugs and exhibited potential to predict the outcome of immunotherapy. We also comprehensively identified cuproptosis-related microRNAs, long noncoding RNAs, and transcription factors. We provided the code corresponding to the results of this study in GitHub (https://github.com/Changwuuu/Cuproptosis-pancancer.git) for reference. In summary, this study reveals important molecular and clinical characteristics of cuproptosis regulators and cuproptosis activity in tumors, and suggests the use of cuproptosis as a promising tumor therapeutic approach. This study provides an important reference point for future cuproptosis-related research.

Disulfiram Enhances the Antineoplastic Activity and Sensitivity of Murine Hepatocellular Carcinoma to 5-FU via Redox Management

The efficacy of anticancer drug 5-FU is suppressed due to various factors, including severe side effects and decreased insensitivity during prolonged chemotherapy. Elevated endogenous copper (Cu) levels are one of the prominent hallmark features of cancer cells. In the present investigation, this feature was targeted in diethyl nitrosamine-phenobarbital-induced hepatocellular carcinoma (HCC) in a rat model system by an established anticancer drug, 5-FU, co-administered with copper and its chelating agent, disulfiram. After treatment with the test chemicals in HCC-induced rats, blood and liver samples were subjected to biochemical, molecular, and histopathological analyses. The analysis revealed that reactive oxygen species-mediated oxidative stress is the crucial etiological reason for the pathogenesis of HCC in rats, as evidenced by the significantly compromised activity of major antioxidant enzymes and elevated levels of oxidative damaged products with major histological alterations compared to the control. However, the combination of 5-FU with DSF demonstrated a significant improvement in most of the parameters, followed by 5-FU-Cu in the combination-treated groups. The combination treatment improved the histological details and triggered apoptosis in the cancer cells to a remarkable extent, as the levels of cleaved PARP and caspase-3 were significantly higher than those in the HCC rats treated with the drug alone. The present study envisages that manipulating the Cu-level greatly enhances the antineoplastic activity of 5-FU and sensitizes cancer cells to the increased efficacy of the drug.

Identification of biomarkers related to copper metabolism in patients with pulmonary arterial hypertension

BACKGROUND

The pathogenesis of pulmonary arterial hypertension (PAH) and associated biomarkers remain to be studied. Copper metabolism is an emerging metabolic research direction in many diseases, but its role in PAH is still unclear.

METHODS

PAH-related datasets were downloaded from the Gene Expression Omnibus database, and 2067 copper metabolism-related genes (CMGs) were obtained from the GeneCards database. Differential expression analysis and the Venn algorithm were used to acquire the differentially expressed CMGs (DE-CMGs). DE-CMGs were then used for the coexpression network construction to screen candidate key genes associated with PAH. Furthermore, the predictive performance of the model was verified by receiver operating characteristic (ROC) analysis, and genes with area under the curve (AUC) values greater than 0.8 were selected as diagnostic genes. Then support vector machine, least absolute shrinkage and selection operator regression, and Venn diagrams were applied to detect biomarkers. Moreover, gene set enrichment analysis was performed to explore the function of the biomarkers, and immune-related analyses were utilized to study the infiltration of immune cells. The drug-gene interaction database was used to predict potential therapeutic drugs for PAH using the biomarkers. Biomarkers expression in clinical samples was verified by real-time quantitative PCR.

RESULTS

Four biomarkers (DDIT3, NFKBIA, OSM, and PTGER4) were screened. The ROC analysis showed that the 4 biomarkers performed well (AUCs > 0.7). The high expression groups for the 4 biomarkers were enriched in protein activity-related pathways including protein export, spliceosome and proteasome. Furthermore, 8 immune cell types were significantly different between the two groups, including naive B cells, memory B cells, and resting memory CD4 T cells. Afterward, a gene-drug network was constructed. This network illustrated that STREPTOZOCIN, IBUPROFEN, and CELECOXIB were shared by the PTGER4 and DDIT3. Finally, the results of RT-qPCR in clinical samples further confirmed the results of the public database for the expression of NFKBIA and OSM.

CONCLUSION

In conclusion, four biomarkers (DDIT3, NFKBIA, OSM, and PTGER4) with considerable diagnostic values were identified, and a gene-drug network was further constructed. The results of this study may have significant implications for the development of new diagnostic biomarkers and actionable targets to expand treatment options for PAH patients.

Copper transporter gene ATP7A: A predictive biomarker for immunotherapy and targeted therapy in hepatocellular carcinoma

BACKGROUND

ATP7A is an important copper transporter that regulates numerous cellular biological processes. However, the role of ATP7A in immunotherapy and targeted therapy, especially for hepatocellular carcinoma (HCC), remains unknown.

METHODS

We analyzed ATP7A expression and its effect on digestive system tumor prognoses, assessed its expression in tissue microarrays from 319 HCC patients, and investigated the relationship between ATP7A expression and tumor immunity. Specifically, we evaluated the possible association between ATP7A and programmed death ligand 1 (PD-L1) expression in human HCC tissues. Finally, we analyzed the effect of ATP7A on sorafenib efficacy in HCC.

RESULTS

ATP7A is generally highly expressed in digestive system tumors but related to poor prognosis only in HCC. ATP7A levels are positively associated with immune cell infiltration and immune checkpoint expression (especially PD-L1). HCC patients coexpressing APT7A and PD-L1 demonstrate poor prognoses. Moreover, HCC patients with high ATP7A levels were more sensitive to sorafenib and demonstrated higher survival rates after sorafenib treatment.

CONCLUSIONS

This study provides insights into the correlation between ATP7A levels and tumor immune infiltration and immune checkpoint function in HCC, sheds light on the significance of ATP7A in cancer progression, and provides guidance for more effective and general therapeutic strategies.

Copper regulation disturbance linked to oxidative stress and cell death during Zika virus infection in human astrocytes

The Zika virus (ZIKV) caused neurological abnormalities in more than 3500 Brazilian newborns between 2015 and 2020. Data have pointed to oxidative stress in astrocytes as well as to dysregulations in neural cell proliferation and cell cycle as important events accounting for the cell death and neurological complications observed in Congenital Zika Syndrome. Copper imbalance has been shown to induce similar alterations in other pathologies, and disturbances in copper homeostasis have already been described in viral infections. Here, we investigated copper homeostasis imbalance as a factor that could contribute to the cytotoxic effects of ZIKV infection in astrocytes. Human induced pluripotent stem cell-derived astrocytes were infected with ZIKV; changes in the gene expression of copper homeostasis proteins were analyzed. The effect of the administration of CuCl₂ or a copper chelator on oxidative stress, cell viability and percentage of infection were also studied. ZIKV infection leads to a downregulation of one of the transporters mediating copper release, ATP7B protein. We also observed the activation of mechanisms that counteract high copper levels, including the synthesis of copper chaperones and the reduction of the copper importer protein CTR1. Finally, we show that chelator-mediated copper sequestration in ZIKV-infected astrocytes reduces the levels of reactive oxygen species and improves cell viability, but does not change the overall percentage of infected cells. In summary, our results show that copper homeostasis imbalance plays a role in the pathology of ZIKV in astrocytes, indicating that it may also be a factor accounting for the developmental abnormalities in the central nervous system following viral infection. Evaluating micronutrient levels and the use of copper chelators in pregnant women susceptible to ZIKV infection may be promising strategies to manage novel cases of congenital ZIKV syndrome.

Subcellular redox responses reveal different Cu-dependent antioxidant defenses between mitochondria and cytosol

Excess intracellular Cu perturbs cellular redox balance and thus causes diseases. However, the relationship between cellular redox status and Cu homeostasis and how such an interplay is coordinated within cellular compartments has not yet been well established. Using combined approaches of organelle-specific redox sensor Grx1-roGFP2 and non-targeted proteomics, we investigate the real-time Cu-dependent antioxidant defenses of mitochondria and cytosol in live HEK293 cells. The Cu-dependent real-time imaging experiments show that CuCl2 treatment results in increased oxidative stress in both cytosol and mitochondria. In contrast, subsequent excess Cu removal by bathocuproine sulfonate, a Cu chelating reagent, lowers oxidative stress in mitochondria but causes even higher oxidative stress in the cytosol. The proteomic data reveal that several mitochondrial proteins, but not cytosolic ones, undergo significant abundance change under Cu treatments. The proteomic analysis also shows that proteins with significant changes are related to mitochondrial oxidative phosphorylation and glutathione synthesis. The differences in redox behaviors and protein profiles in different cellular compartments reveal distinct mitochondrial and cytosolic response mechanisms upon Cu-induced oxidative stress. These findings provide insights into how redox and Cu homeostasis interplay by modulating specific protein expressions at the subcellular levels, shedding light on understanding the effects of Cu-induced redox misregulation on the diseases.

Proteomics revealed the crosstalk between copper stress and cuproptosis, and explored the feasibility of curcumin as anticancer copper ionophore

As an essential micronutrient element in organisms, copper controls a host of fundamental cellular functions. Recently, copper-dependent cell growth and proliferation have been defined as "cuproplasia". Conversely, "cuproptosis" represents copper-dependent cell death, in a nonapoptotic manner. So far, a series of copper ionophores have been developed to kill cancer cells. However, the biological response mechanism of copper uptake has not been systematically analyzed. Based on quantitative proteomics, we revealed the crosstalk between copper stress and cuproptosis in cancer cells, and also explored the feasibility of curcumin as anticancer copper ionophore. Copper stress not only couples with cuproptosis, but also leads to reactive oxygen species (ROS) stress, oxidative damage and cell cycle arrest. In cancer cells, a feedback cytoprotection mechanism involving cuproptosis mediators was discovered. During copper treatment, the activation of glutamine transporters and the loss of Fe-S cluster proteins are the facilitators and results of cuproptosis, respectively. Through copper depletion, glutathione (GSH) blocks the cuproptosis process, rescues the activation of glutamine transporters, and prevents the loss of Fe-S cluster proteins, except for protecting cancer cells from apoptosis, protein degradation and oxidative damage. In addition, the copper ionophore curcumin can control the metabolisms of lipids, RNA, NADH and NADPH in colorectal cancer cells, and also up-regulates positive cuproptosis mediators. This work not only established the crosstalk between copper stress and cuproptosis, but also discolored the suppression and acceleration of cuproptosis by GSH and curcumin, respectively. Our results are significant for understanding cuproptosis process and developing novel anticancer reagents based on cuproptosis.

Relationship between copper and immunity: The potential role of copper in tumor immunity

Copper is an essential trace element in an organism, and changes in copper levels in vivo often indicate a diseased state. Copper and immunity have been discussed since the last century, with copper deficiency significantly affecting the development and function of the immune system, such as increased host susceptibility to various pathogens, decreased number and impaired function of neutrophils, reduced antibacterial activity of macrophages, decreased proliferation of splenocytes, impaired B cell ability to produce antibodies and impaired function of cytotoxic T lymphocyte and helper T cells. In the past 20 years, some studies have shown that copper ions are related to the development of many tumors, including lung cancer, acute lymphoid leukaemia, multiple myeloma and other tumors, wherein copper ion levels were significantly elevated, and current studies reveal that copper ions are involved in the development, growth and metastasis of tumors through various pathways. Moreover, recent studies have shown that copper ions can regulate the expression of PD-L1, thus, attention should be paid to the important role of copper in tumor immunity. By exploring and studying copper ions and tumor immunity, new insights into tumor immunity could be generated and novel therapeutic approaches to improve the clinical prognosis of patients can be provided.

Crystal Structure of the Human Copper Chaperone ATOX1 Bound to Zinc Ion

The bioavailability of copper (Cu) in human cells may depend on a complex interplay with zinc (Zn) ions. We investigated the ability of the Zn ion to target the human Cu-chaperone Atox1, a small cytosolic protein capable of anchoring Cu(I), by a conserved surface-exposed Cys-X-X-Cys (CXXC) motif, and deliver it to Cu-transporting ATPases in the trans-Golgi network. The crystal structure of Atox1 loaded with Zn displays the metal ion bridging the CXXC motifs of two Atox1 molecules in a homodimer. The identity and location of the Zn ion were confirmed through the anomalous scattering of the metal by collecting X-ray diffraction data near the Zn K-edge. Furthermore, soaking experiments of the Zn-loaded Atox1 crystals with a strong chelating agent, such as EDTA, caused only limited removal of the metal ion from the tetrahedral coordination cage, suggesting a potential role of Atox1 in Zn metabolism and, more generally, that Cu and Zn transport mechanisms could be interlocked in human cells.

Copper (I) or (II) Replacement of the Structural Zinc Ion in the Prokaryotic Zinc Finger Ros Does Not Result in a Functional Domain

A strict interplay is known to involve copper and zinc in many cellular processes. For this reason, the results of copper’s interaction with zinc binding proteins are of great interest. For instance, copper interferences with the DNA-binding activity of zinc finger proteins are associated with the development of a variety of diseases. The biological impact of copper depends on the chemical properties of its two common oxidation states (Cu(I) and Cu(II)). In this framework, following the attention addressed to unveil the effect of metal ion replacement in zinc fingers and in zinc-containing proteins, we explore the effects of the Zn(II) to Cu(I) or Cu(II) replacement in the prokaryotic zinc finger domain. The prokaryotic zinc finger protein Ros, involved in the horizontal transfer of genes from A. tumefaciens to a host plant infected by it, belongs to a family of proteins, namely Ros/MucR, whose members have been recognized in different bacteria symbionts and pathogens of mammals and plants. Interestingly, the amino acids of the coordination sphere are poorly conserved in most of these proteins, although their sequence identity can be very high. In fact, some members of this family of proteins do not bind zinc or any other metal, but assume a 3D structure similar to that of Ros with the residues replacing the zinc ligands, forming a network of hydrogen bonds and hydrophobic interactions that surrogates the Zn-coordinating role. These peculiar features of the Ros ZF domain prompted us to study the metal ion replacement with ions that have different electronic configuration and ionic radius. The protein was intensely studied as a perfectly suited model of a metal-binding protein to study the effects of the metal ion replacement; it appeared to tolerate the Zn to Cd substitution, but not the replacement of the wildtype metal by Ni(II), Pb(II) and Hg(II). The structural characterization reported here gives a high-resolution description of the interaction of copper with Ros, demonstrating that copper, in both oxidation states, binds the protein, but the replacement does not give rise to a functional domain.

Memo1 binds reduced copper ions, interacts with copper chaperone Atox1, and protects against copper-mediated redox activity in vitro

Since many proteins depend on copper ions for functionality, it is not surprising that cancer cells have a high demand for copper. Still, free copper ions are toxic as they can potentially catalyze the formation of harmful reactive oxygen species (ROS) upon coupling redox cycling between Cu(I) and Cu(II) with reduction of O₂. Here, we investigated copper binding to Memo1, an oncogenic protein linked to cancer. We demonstrate that Memo1 coordinates reduced but not oxidized copper ions, thereby preventing the copper ions from acting as redox catalysts for ROS generation. As Memo1 is a putative target for the treatment of cancer, it is of importance to identify its binding partners (e.g., metal ions) and the functional consequences of such interactions.

The protein mediator of ERBB2-driven cell motility 1 (Memo1) is connected to many signaling pathways that play key roles in cancer. Memo1 was recently postulated to bind copper (Cu) ions and thereby promote the generation of reactive oxygen species (ROS) in cancer cells. Since the concentration of Cu as well as ROS are increased in cancer cells, both can be toxic if not well regulated. Here, we investigated the Cu-binding capacity of Memo1 using an array of biophysical methods at reducing as well as oxidizing conditions in vitro. We find that Memo1 coordinates two reduced Cu (Cu(I)) ions per protein, and, by doing so, the metal ions are shielded from ROS generation. In support of biological relevance, we show that the cytoplasmic Cu chaperone Atox1, which delivers Cu(I) in the secretory pathway, can interact with and exchange Cu(I) with Memo1 in vitro and that the two proteins exhibit spatial proximity in breast cancer cells. Thus, Memo1 appears to act as a Cu(I) chelator (perhaps shuttling the metal ion to Atox1 and the secretory path) that protects cells from Cu-mediated toxicity, such as uncontrolled formation of ROS. This Memo1 functionality may be a safety mechanism to cope with the increased demand of Cu ions in cancer cells.

Metallome deregulation and health-related impacts due to long-term exposure to recent volcanic ash deposits: New chemical and isotopic insights

Volcanic ash exposure can lead to significant health risks. Damage to the respiratory and pulmonary systems are the most evident toxic side effects although the causes of these symptoms remain unclear. Conversely, the effects on other organs remain largely under-explored, limiting our understanding of the long-term volcanic ash-related risk at the whole-body scale. The metallome i.e. metal concentrations and isotopic compositions within the body, is suspected to be affected by volcanic ash exposure, having thus the potential for capturing some specificities of ash toxicity. However, the means by and extent to which the metallome is affected at the entire body scale and how the consequent chemical and isotopic deregulations correlate with pathophysiological dysfunctions are currently poorly understood. Here, we adopt a transdisciplinary approach combining high precision chemical analyses (major and trace element concentrations) and CuZn isotope measurements in seven organs and two biological fluids of isogenic mice (C57BL/6) exposed to eruption products from La Soufrière de Guadeloupe (Eastern Carribean), in tandem with biological parameters including physiological and morphological data. Based on principal component analysis, we show that after one month of exposure to volcanic ash deposits, the mice metallome; originally organ-specific and isotopically-typified, is highly disrupted as shown for example by heavy metal accumulation in testis (e.g., Fe, Zn) and Cu, Zn isotopic divergence in liver, intestine and blood. These metallomic variations are correlated with early testicular defects and might reflect the warning signs of premature (entero)hepatic impairments that may seriously affect fertility and favor the emergence of liver diseases after prolonged exposure. Monitoring the temporal evolution of the Cu and Zn isotope compositions seems to be a promising technique to identify the main biological processes and vital functions that are vulnerable to environmental volcanogenic pollutants although this will require further validation on human subjects.

Incorporation of Rhodamine into a Host Polymer via In-Situ Generated Isocyanato Group and Application for the Detection of Cu2+ Ion

A rhodamine-based fluorescent polymer P(MMA-co-RB) has been synthesized via an intermediate NCO-containing polymer generated by the Lossen rearrangement reaction. The fluorescent property of P(MMA-co-RB) with regard to metal ions, such as Cu2+, Fe3+, Cr3+, Al3+, Zn2+, Co2+, Sn2+ and Ag+, was studied by fluorescence emission spectroscopy. The results demonstrate that the fluorescence intensity of P(MMA-co-RB) decreased gradually with an increase of the concentration of Cu2+ ion. Furthermore, a test strip made of P(MMA-co-RB) can be used for fast and quantitative determination of Cu2+ ion. In the presence of Cu2+ ion, the sensory tester undergoes distinct changes in fluorescence intensity and visible color.

Copper Modulates Mitochondrial Oxidative Phosphorylation to Enhance Dermal Papilla Cells Proliferation in Rex Rabbits

Copper (Cu) is an important coenzyme factor in cell signaling, such as cytochrome c oxidase (Complex IV). Metabolism plays an important role in regulating the fate of mammalian cells. The aim of this study is to experimentally investigate the effect of copper on cell metabolism in the dermal papilla cells of the Rex rabbit. In this study, Cu promoted proliferation of dermal papilla cells (p = 0.0008) while also increasing levels of cellular CIII, CIV, Complex IV and ATP. Moreover, fifty metabolites that were significantly different between Cu and controls were identified as potential biomarkers of Cu stimulation. Copper-stimulated cells had altered levels of arachidonic acid derivatives, S-glutamic acid, and citric acid, which were primarily linked to two different pathways: arachidonic acid metabolism (p < 0.0001) and alanine, aspartate and glutamate metabolism (p = 0.0003). The addition of Cu can increase the proliferation of Rex rabbit dermal papilla cells. Increased levels of ubiquinol-cytochrome c reductase complex core protein 2 (CIII) and cytochrome c oxidase subunit 1 (CIV) were associated with the increased levels of cellular cytochrome c oxidase (Complex IV) and adenosine triphosphate (ATP). In a word, copper promotes cell proliferation by maintaining the function of the cellular mitochondrial electron transport chain (ETC) pathway.

Metal binding and interdomain thermodynamics of mammalian metallothionein-3: enthalpically favoured Cu+ supplants entropically favoured Zn2+ to form Cu4 + clusters under physiological conditions

Metallothioneins (MTs) are a ubiquitous class of small metal-binding proteins involved in metal homeostasis and detoxification. While known for their high affinity for d¹⁰ metal ions, there is a surprising dearth of thermodynamic data on metals binding to MTs. In this study, Zn²⁺ and Cu⁺ binding to mammalian metallothionein-3 (MT-3) were quantified at pH 7.4 by isothermal titration calorimetry (ITC). Zn²⁺ binding was measured by chelation titrations of Zn₇MT-3, while Cu⁺ binding was measured by Zn²⁺ displacement from Zn₇MT-3 with competition from glutathione (GSH). Titrations in multiple buffers enabled a detailed analysis that yielded condition-independent values for the association constant (K) and the change in enthalpy (ΔH) and entropy (ΔS) for these metal ions binding to MT-3. Zn²⁺ was also chelated from the individual α and β domains of MT-3 to quantify the thermodynamics of inter-domain interactions in metal binding. Comparative titrations of Zn₇MT-2 with Cu⁺ revealed that both MT isoforms have similar Cu⁺ affinities and binding thermodynamics, indicating that ΔH and ΔS are determined primarily by the conserved Cys residues. Inductively coupled plasma mass spectrometry (ICP-MS) analysis and low temperature luminescence measurements of Cu-replete samples showed that both proteins form two Cu₄ ⁺-thiolate clusters when Cu⁺ displaces Zn²⁺ under physiological conditions. Comparison of the Zn²⁺ and Cu⁺ binding thermodynamics reveal that enthalpically-favoured Cu⁺, which forms Cu₄ ⁺-thiolate clusters, displaces the entropically-favoured Zn²⁺. These results provide a detailed thermodynamic analysis of d¹⁰ metal binding to these thiolate-rich proteins and quantitative support for, as well as molecular insight into, the role that MT-3 plays in the neuronal chemistry of copper.

Engineered lanthanide-doped upconversion nanoparticles for biosensing and bioimaging application

Various fluctuations of intracellular ions, biomolecules, and other conditions in the physiological environment play crucial roles in fundamental biological processes. These factors are of great importance for analysis in biomedical detection. Nevertheless, developments of the simple, rapid, and accurate proof for specific detection still encounter major challenges. Upconversion nanoparticles (UCNPs), which could absorb multiple low-energy near-infrared light (NIR) photon excitation and emits high-energy photons caused by anti-Stokes shift, show unique upconversion luminescence (UCL) properties, for example, sharp emission band, high physicochemical stability like near-zero photobleaching, photo blinking in biological tissues, and long luminescence lifetime. Furthermore, the NIR used for the light source to excite UCNPs enable lower photo-damage effect and deeper penetration of tissue, and in the meantime, it can avoid the auto-fluorescence and light scattering from biological tissue interference. Thus, the lanthanide-doped UCNP-based functional platform with controlled structure, crystalline phase, size, and multicolor emission has become an appropriate nanomaterial for bioapplications such as biosensing, bioimaging, drug release, and therapies. In this review, the recent progress about synthesis and biomedical applications of UCNPs related to sensing and bioimaging is summarized. Firstly, the different luminescence mechanisms of the upconversion process are presented. Secondly, four of the most common methods for synthesizing UCNPs are compared as well as the advantages and disadvantages of these synthetic routes. Meanwhile, the surface modification of lanthanide-doped UCNPs was introduced to pave the way for their biochemistry applications. Next, this review detailed the biological applications of lanthanide-doped UCNPs, particularly in bioimaging, including UCL and multi-modal imaging and biosensing (monitoring intracellular ions and biomolecules). Finally, the challenges and future perspectives in materials science and biomedical fields of UCNPs are concluded: the low quantum yield of the upconversion process should be considered when they are executed as imaging contrast agents. And the biosafety of lanthanide-doped UCNPs needs to be evaluated.