Targeting copper in cancer therapy: 'Copper That Cancer'

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.

Polyimidazole ligands: Copper(II) complexes and antiproliferative activity in cancer cells

The design of novel chelators for therapeutic applications has been the subject of extensive research to address various diseases. Many chelators can manipulate the levels of metal ions within cells and effectively modulate the metal excess. In some cases, chelators show significant toxicity to cells. We investigated polyimidazole ligands by potentiometry and UV-Vis spectroscopy for their ability to form copper(II) complexes. We also compared the antiproliferative activity of the polyimidazole ligands and their copper(II) complexes with polypyridine ligands in CaCo-2 (colorectal adenocarcinoma), SH-SY5Y (neuroblastoma) and K562 (chronic myelogenous leukemia) cells and normal HaCaT (keratinocyte) cells. Polyimidazole ligands are less cytotoxic than their analogous polypyridine ligands. All polyimidazole ligands, except the tetraimidazole ligand for K562 cells, did not show any significant effect on the viability of cancer and normal cells. In contrast, the cytotoxic activity of polypiridine ligands was also observed in normal cells with IC50 values similar to those of cancer cells. Tetraimidazole ligand, the only ligand active on the leukemic K562 cell line, induced caspase-dependent apoptosis and increased intracellular reactive oxygen species production with mitochondrial damage. The low cytotoxicity of the polyimidazole ligands, even if it limits their use as anticancer agents, could make them useful in other medical applications, such as in the treatment of metal overload, microbial infections, inflammation or neurodegenerative disorders.

Anticancer activity of new water-soluble sulfonated thiosemicarbazone copper(II) complexes targeting disulfide isomerase

Copper complexes have shown promising anticancer properties, but they are often poorly soluble in aqueous solutions, thus limiting their possible medical developments and applications. We have recently isolated some copper(II) complexes with salicylaldehyde thiosemicarbazone ligands exhibiting remarkable nanomolar cytotoxic activity, but in vivo tests evidenced several difficulties related to their poor solubility. To overcome these limitations and increase solubility in aqueous solution, herein we report the synthetic strategy that led to the introduction of the sulfonic group on the ligands, then separated as salts (NaH2L1 - NaH2L5), as well as the synthesis and characterization of the related copper(II) complexes. The characterization of the complexes is completed by the analysis of the structures obtained by X-rays diffraction on single crystals on the species [Cu(HL5)(H2O)]2.2H2O, [Cu(HL2)(H2O)2].2H2O, and [Cu(HL1)(H2O]2.2H2O. While the uncoordinated ligands do not affect cancer cell viability, copper(II) complexes exhibit low to sub-micromolar cytotoxic activity, which is maintained in 3D (HCT-15 and 2008) spheroidal models of cancer cell. Notably, copper(II) complexes were selective towards cancer cells, showing high selectivity indexes. Investigations focused on elucidating the mechanism of action evidenced the protein disulfide-isomerase as an innovative molecular target for this class of water-soluble copper(II) complexes. Finally, preliminary in vivo experiments performed with the most representative derivative in the murine Lewis Lung Carcinoma, highlight its significant antitumor efficacy and better tolerability profile with respect to the reference metallodrug, suggesting for this sulfonated Cu(II) complex a potential clinical relevance.

Activatable Heavy-Atom-Free Photosensitizer with Large Stokes Shift and a NIR-II Emission Harnessing Rhodamine Ring-Opening Strategy

Activatable photosensitizers (PSs) generating 1O2 only under specific conditions can minimize concomitant injury to normal tissues. Heavy-atom-free PSs hold the merits of low dark toxicity, long triplet-state lifetimes, good photostability, and relatively low cost. PSs with emission in the second near-infrared (NIR-II) window are highly valuable for deep-tissue, high-contrast imaging. Herein, we have designed and synthesized a series of heavy-atom-free PSs by a one-step reaction between an easily accessible rhodamine derivative and commercially available thiophene aldehydes. One of the as-prepared PSs, 2b-3T, exhibits emission maxima at 810 nm and tails to the NIR-II region at 1140 nm, together with large Stokes shift (178 nm). Importantly, the newly developed PSs, featuring functional carboxylic acid groups, present promising opportunities as versatile platforms for creating activatable PSs. To validate our concept, we developed Cu2+/pH-activatable PSs using the spirocyclization mechanism of rhodamine. Ultimately, we showcased the effectiveness of these innovative PSs in photodynamic therapy through in vitro experiments.

Focus on cuproptosis: Exploring new mechanisms and therapeutic application prospects of cuproptosis regulation

Cuproptosis is a novel form of regulated cell death, which plays an important role in the physiological and pathological processes of the human body. Despite the increasing research on cuproptosis-related genes (CRGs) and their correlation with diseases, the pathogenesis of cuproptosis-related diseases remains unclear. Furthermore, there is a lack of reviews on the emerging technologies for regulating cuproptosis in disease treatment. This study delves into the copper-induced cell death mechanism, distinguishing cuproptosis from mechanisms like oxidative stress, glutathione synthesis inhibition, and ubiquitin-proteasome system inhibition. Several long-standing mysteries of diseases such as Wilson's disease and Menkes disease may be attributed to the occurrence of cuproptosis. In addition, we also review the detection indicators related to cuproptosis, providing targets for the diagnosis of cuproptosis-related diseases, and summarize the application value of cuproptosis in tumor therapy to better elucidate the impact of copper in cell death and diseases, and thus to promote the application prospects and possible strategies of cuproptosis-related substances, such as copper ion chelators, copper ion carriers, and copper nanomaterials, in disease therapy.

Review Article on Molecular Basis of Zinc and Copper Interactions in Cancer Physiology

Various clinical manifestations associated with measurable abnormalities of Zn and Cu in serum and tissue were determined in Cancer-Patients (CP), and therefore, these two metals are drawing more and more attention presently than ever before. Cancer is a disease of uncontrolled-abnormal-cell-division with invasion-potential which was exhibited to occur due to dys-regulation/dys-homeostasis of fundamental-biological-pathways (FBP) including antioxidant-enzyme-defense-system, anti-inflammatory and immune-systems, and DNA-damage-repair-system in the human-body resulting in generation of chronic-oxidative-stress induced DNA-damage and gene-mutations, inflammation and compromised immune-system, tumor-induced increased angiogenesis, and inhibition of apoptosis processes. Zn and Cu were recognized to be the most crucial components of FBP and imbalance in Zn/Cu ratios in CP asserted to generate chronic toxicity in human body through various mechanisms including increased chronic oxidative stress linked compromised DNA integrity and gene mutations due to malfunctioning of DNA damage repair enzymes; increased angiogenesis process due to Zn- and Cu-binding proteins metallothionein and ceruloplasmin-induced enhanced expression of tumor growth factors; and elevation in inflammatory response which was further shown to down/upregulate gene expression of multiple Zn transporter proteins leading to dys-homeostasis of intracellular Zn concentrations, and it was determined to disturb the equilibrium between cell growth and division, proliferation, differentiation, and apoptosis processes which lead to cancer progression. Moreover, Zn was reported to affect matrix metalloproteinase activity and influence immune system cells to respond differently to different cytokines and enhance immune-suppressive effects accelerating the angiogenesis, invasion, and metastasis potential in cancer. Further, the most significant use of serum Cu/Zn ratio was recommended in clinical diagnosis, prognosis, tumor stage, patient survival, and cancer follow-up studies which need further investigations to elucidate and explore their roles in cancer physiology for clinical perspective.

m6A modification of lipoyltransferase 1 inhibits bladder cancer progression by activating cuproptosis

Cuproptosis, a cell death process caused by copper ions, is mediated by protein lipidation related to lipoic acid metabolism. There is a close connection between cuproptosis and the progression and prognosis of various tumors. Here, we identified lipoyltransferase 1 (LIPT1), a key gene related to cuproptosis, was downregulated in bladder cancer (BLCA) and was associated with unfavorable patient prognosis. Restoring the LIPT1 expression in BLCA cells suppressed the proliferation and promoted cuproptosis. Moreover, the consequences of RNA sequencing and Bodipy staining showed that the metabolic pathway mediated by LIPT1 inhibited the accumulation of lipid droplets in cells, disrupted endoplasmic reticulum (ER) homeostasis, and promoted cell apoptosis. Additionally, overexpression of LIPT1 not only repressed the proliferation rate of BLCA cells in vitro but also in vivo. Mechanistically, YTH N6-Methyladenosine RNA Binding Protein F2 (YTHDF2) promoted the degradation of LIPT1 mRNA in a m6A-dependent manner. In summary, these conclusions reveal that LIPT1 promotes cuprotosis and ER stress to inhibit the progression of BLCA, indicating that LIPT1 will provide a powerful treatment direction and drug target for treating BLCA.

PTPN2 copper-sensing relays copper level fluctuations into EGFR/CREB activation and associated CTR1 transcriptional repression

Fluxes in human copper levels recently garnered attention for roles in cellular signaling, including affecting levels of the signaling molecule cyclic adenosine monophosphate. We herein apply an unbiased temporal evaluation of the signaling and whole genome transcriptional activities modulated by copper level fluctuations to identify potential copper sensor proteins responsible for driving these activities. We find that fluctuations in physiologically relevant copper levels modulate EGFR signal transduction and activation of the transcription factor CREB. Both intracellular and extracellular assays support Cu1+ inhibition of the EGFR phosphatase PTPN2 (and potentially PTPN1)-via ligation to the PTPN2 active site cysteine side chain-as the underlying mechanism. We additionally show i) copper supplementation drives weak transcriptional repression of the copper importer CTR1 and ii) CREB activity is inversely correlated with CTR1 expression. In summary, our study reveals PTPN2 as a physiological copper sensor and defines a regulatory mechanism linking feedback control of copper stimulated EGFR/CREB signaling and CTR1 expression.

Is Copper Still Safe for Us? What Do We Know and What Are the Latest Literature Statements?

Copper (Cu) is a precious metal and one of the three most abundant trace elements in the body (50-120 mg). It is involved in a large number of cellular mechanisms and pathways and is an essential cofactor in the function of cellular enzymes. Both its excess and deficiency may be harmful for many diseases. Even small changes in Cu concentration may be associated with significant toxicity. Consequently, it can be damaging to any organ or tissue in our body, beginning with harmful effects already at the molecular level and then affecting the degradation of individual tissues/organs and the slow development of many diseases, such as those of the immunological system, skeletal system, circulatory system, nervous system, digestive system, respiratory system, reproductive system, and skin. The main purpose of this article is to review the literature with regard to both the healthiness and toxicity of copper to the human body. A secondary objective is to show its widespread use and sources, including in food and common materials in contact with humans. Its biological half-life from diet is estimated to range from 13 to 33 days. The retention or bioavailability of copper from the diet is influenced by several factors, such as age, amount and form of copper in the diet, lifestyle, and genetic background. The upper limit of normal in serum in healthy adults is approximately 1.5 mg Cu/L, while the safe upper limit of average intake is set at 10-12 mg/day, the reference limit at 0.9 mg/day, and the minimum limit at 0.6-0.7 mg/day. Cu is essential, and in the optimal dose, it provides antioxidant defense, while its deficiency reduces the body's ability to cope with oxidative stress. The development of civilization and the constant, widespread use of Cu in all electrical devices will not be stopped, but the health of people directly related to its extraction, production, or distribution can be controlled, and the inhabitants of nearby towns can be protected. It is extremely difficult to assess the effects of copper on the human body because of its ubiquity and the increasing reports in the literature about its effects, including copper nanoparticles.

Plumbagin's Antiproliferative Mechanism in Human Cancer Cells: A Copper-Dependent Cytotoxic Approach

Cancer is a serious global health problem, causing the loss of millions of lives each year. Plumbagin, a compound derived from the medicinal plant Plumbago zeylanica, has shown promise in stopping the growth of tumor cells both in laboratory settings and in living organisms. Many plant-based compounds exert their effects through copper's ability to produce reactive oxygen species (ROS). This study aimed to understand how plumbagin, dependent on copper, induces cell death (apoptosis) in human cancer cells through various experiments. The results demonstrate that plumbagin hinders the growth of pancreatic cancer cells PNAC-1 and MIA PaCa-2 by utilizing the copper naturally present in the cells. Unlike metal chelators that remove iron and zinc (desferrioxamine mesylate and histidine), a specific copper chelator called neocuproine lessens the cell death caused by plumbagin. When ROS scavengers are used, plumbagin-induced apoptosis is inhibited, indicating that ROS plays a role in initiating cell death. The study also proves that plumbagin prevents copper from leaving cancer cells by suppressing the expression of specific genes (CTR1 and ATP7A). It is confirmed that plumbagin targets the nuclear copper, leading to signals that promote oxidative stress and, ultimately, cell death. These findings provide valuable insights into the potential of plumbagin as a substance to combat cancer, highlighting the importance of understanding how copper behaves within cancer cells.

Copper metabolism and its role in diabetic complications: A review

Disturbances in copper (Cu) homeostasis have been observed in diabetes and associated complications. Cu is an essential micronutrient that plays important roles in various fundamental biological processes. For example, diabetic cardiomyopathy is associated with elevated levels of Cu in the serum and tissues. Therefore, targeting Cu may be a novel treatment strategy for diabetic complications. This review provides an overview of physiological Cu metabolism and homeostasis, followed by a discussion of Cu metabolism disorders observed during the occurrence and progression of diabetic complications. Finally, we discuss the recent therapeutic advances in the use of Cu coordination complexes as treatments for diabetic complications and their potential mechanisms of action. This review contributes to a complete understanding of the role of Cu in diabetic complications and demonstrates the broad application prospects of Cu-coordinated compounds as potential therapeutic agents.

The functions of cuproptosis in gastric cancer: therapy, diagnosis, prognosis

Gastric cancer (GC) is the fifth most prevalent type of cancer in the whole world. Cuproptosis is discovered as a programmed cell death pathway and connected to cells' growth and death, as well as tumorigenesis. The relationship between cuproptosis and GC is still elusive. Two aspects of this study will elaborate the relationship between cuproptosis and immunotherapy as well as biomarkers in GC. Notably, the herein review is intended to highlight what has been accomplished regarding the cuproptosis for the diagnosis, immunotherapy, and prognosis in GC. The aim of this study is to offer a potential directions and the strategies for future research regarding cuproptosis inside the GC.

Cuproptosis, the novel type of oxidation-induced cell death in thoracic cancers: can it enhance the success of immunotherapy?

Copper is an important metal micronutrient, required for the balanced growth and normal physiological functions of human organism. Copper-related toxicity and dysbalanced metabolism were associated with the disruption of intracellular respiration and the development of various diseases, including cancer. Notably, copper-induced cell death was defined as cuproptosis which was also observed in malignant cells, representing an attractive anti-cancer instrument. Excess of intracellular copper leads to the aggregation of lipoylation proteins and toxic stress, ultimately resulting in the activation of cell death. Differential expression of cuproptosis-related genes was detected in normal and malignant tissues. Cuproptosis-related genes were also linked to the regulation of oxidative stress, immune cell responses, and composition of tumor microenvironment. Activation of cuproptosis was associated with increased expression of redox-metabolism-regulating genes, such as ferredoxin 1 (FDX1), lipoic acid synthetase (LIAS), lipoyltransferase 1 (LIPT1), dihydrolipoamide dehydrogenase (DLD), drolipoamide S-acetyltransferase (DLAT), pyruvate dehydrogenase E1 subunit alpha 1 (PDHA1), and pyruvate dehydrogenase E1 subunit beta (PDHB)). Accordingly, copper-activated network was suggested as an attractive target in cancer therapy. Mechanisms of cuproptosis and regulation of cuproptosis-related genes in different cancers and tumor microenvironment are discussed in this study. The analysis of current findings indicates that therapeutic regulation of copper signaling, and activation of cuproptosis-related targets may provide an effective tool for the improvement of immunotherapy regimens.

Cuproptosis in cancers: Function and implications from bench to bedside

Copper, an indispensable micronutrient, is implicated in numerous vital biological processes and is essential for all physiological activities. Recently, the discovery of a novel type of copper-dependent cell death, known as cuproptosis, has shed light on its role in cancer development. Extensive research is currently underway to unravel the mechanisms underlying cuproptosis and its correlation with various cancer types. In this review, we summarize the findings regarding the roles and mechanisms of cuproptosis in various cancer types, including colorectal cancer, lung cancer, gastric cancer, breast cancer, liver cancer and cutaneous melanoma. Furthermore, the effects of copper-related agents such as copper chelators and copper ionophores on cell proliferation, apoptosis, angiogenesis, tumor immunity, and chemotherapy resistance have been explored in cancer preclinical and clinical trials. These insights provide promising avenues for the development of prospective anticancer drugs aimed at inducing cuproptosis.

Ferroptosis and cuproptosis: Metal-dependent cell death pathways activated in response to classical chemotherapy - Significance for cancer treatment?

Apoptosis has traditionally been regarded as the desired cell death pathway activated by chemotherapeutic drugs due to its controlled and non-inflammatory nature. However, recent discoveries of alternative cell death pathways have paved the way for immune-stimulatory treatment approaches in cancer. Ferroptosis (dependent on iron) and cuproptosis (dependent on copper) hold promise for selective cancer cell targeting and overcoming drug resistance. Copper ionophores and iron-bearing nano-drugs show potential for clinical therapy as single agents and as adjuvant treatments. Here we review up-to-date evidence for the involvement of metal ion-dependent cell death pathways in the cytotoxicity of classical chemotherapeutic agents (alkylating agents, topoisomerase inhibitors, antimetabolites, and mitotic spindle inhibitors) and their combinations with cuproptosis and ferroptosis inducers, indicating the prospects, advantages, and obstacles of their use.

Cuproptosis and Cuproptosis-Based Synergistic Therapy for Cancer Treatment

Copper, as an essential trace nutrient for human, plays a crucial role in numerous cellular activities, and is vital for maintaining homeostasis in organisms. Deviations from normal intracellular copper concentration range can disrupt the cellular homeostasis and lead to cell death. Cell death is the process in which cells lose their vitality and cannot sustain normal metabolism, which has various forms. The recently discovered cuproptosis mechanism differs from the previously recognized forms, which is triggered by intracellular copper accumulation. The discovery of cuproptosis has sparked interest among researchers, and this mechanism has been applied in the treatment of various intractable diseases, including different types of cancer. However, the developed cuproptosis-based therapies have revealed certain limitations, such as low immunostimulatory efficiency, poor tumor targeting, and inhibition by the tumor microenvironment. Therefore, researchers are devoted to combining cuproptosis with existing cancer therapies to develop more effective synergistic cancer therapies. This review summarizes the latest research advancements in the cuproptosis-based therapies for various types of cancer, with a focus on the synergistic cancer therapies. Finally, it provides an outlook on the future development of cuproptosis in anti-tumor therapy.

Cu exposure induces liver inflammation via regulating gut microbiota/LPS/liver TLR4 signaling axis

Copper (Cu) serves as an essential cofactor in all organisms, yet excessive Cu exposure is widely recognized for its role in inducing liver inflammation. However, the precise mechanism by which Cu triggers liver inflammation in ducks, particularly in relation to the interplay in gut microbiota regulation, has remained elusive. In this investigation, we sought to elucidate the impact of Cu exposure on liver inflammation through gut-liver axis in ducks. Our findings revealed that Cu exposure markedly elevated liver AST and ALT levels and induced liver inflammation through upregulating pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) and triggering the LPS/TLR4/NF-κB signaling pathway. Simultaneously, Cu exposure induced alterations in the composition of intestinal flora communities, notably increasing the relative abundance of Sphingobacterium, Campylobacter, Acinetobacter and reducing the relative abundance of Lactobacillus. Cu exposure significantly decreased the protein expression related to intestinal barrier (Occludin, Claudin-1 and ZO-1) and promoted the secretion of intestinal pro-inflammatory cytokines. Furthermore, correlation analysis was observed that intestinal microbiome and gut barrier induced by Cu were closely related to liver inflammation. Fecal microbiota transplantation (FMT) experiments further demonstrated the microbiota-depleted ducks transplanting fecal samples from Cu-exposed ducks disturbed the intestinal dysfunction, which lead to impaire liver function and activate the liver inflammation. Our study provided insights into the mechanism by which Cu exposure induced liver inflammation in ducks through the regulation of gut-liver axis. These results enhanced our comprehension of the potential mechanisms driving Cu-induced hepatotoxicity in avian species.

Thiosemicarbazone Mixed-Valence Cu(I/II) Complex against Lung Adenocarcinoma Cells through Multiple Pathways Involving Cuproptosis

Induction of cuproptosis and targeting of multiple signaling pathways show promising applications in tumor therapy. In this study, we synthesized two thiosemicarbazone-copper complexes ([CuII(L)Cl] 1 and [CuII2CuI(L)2Cl3] 2, where HL is the (E)-N-methyl-2-(phenyl(pyridin-2-yl)methylene ligand), to assess their antilung cancer activities. Both copper complexes showed better anticancer activity than cisplatin and exhibited hemolysis comparable to that of cisplatin. In vivo experiments showed that complex 2 retarded the A549 cell growth in a mouse xenograft model with low systemic toxicity. Primarily, complex 2 kills lung cancer cells in vitro and in vivo by triggering multiple pathways, including cuproptosis. Complex 2 is the first mixed-valent Cu(I/II) complex to induce cellular events consistent with cuproptosis in cancer cells, which may stimulate the development of mixed-valent copper complexes and provide effective cancer therapy.

Biochemical Behavior, Influence on Cell DNA Condition, and Microbiological Properties of Wool and Wool-Copper Materials

The paper presents the study concerning the preparation and physio-chemical and biological properties of wool-copper (WO-Cu) materials obtained by the sputter deposition of copper onto the wool fibers. The WO-Cu material was subjected to physio-chemical and biological investigations. The physio-chemical investigations included the elemental analysis of materials (C, N, O, S, and Cu), their microscopic analysis, and surface properties analysis (specific surface area and total pore volume). The biological investigations consisted of the antimicrobial activity tests of the WO-Cu materials against colonies of Gram-positive (Staphylococcus aureus) bacteria, Gram-negative (Escherichia coli) bacteria, and fungal mold species (Chaetomium globosum). Biochemical-hematological tests included the evaluation of the activated partial thromboplastin time and pro-thrombin time. The tested wool-copper demonstrated the ability to interact with the DNA in a time-dependent manner. These interactions led to the DNA's breaking and degradation. The antimicrobial and antifungal activities of the WO-Cu materials suggest a potential application as an antibacterial/antifungal material. Wool-copper materials may be also used as customized materials where the blood coagulation process could be well controlled through the appropriate copper content.

Utilizing Copper Nanoclusters as a Fluorescent Probe for Quantitative Monitoring of Doxorubicin Anticancer Drug

Monitoring the amount of chemotherapeutic drugs in biological fluids is extremely important for dose adjustment or control of side effects during the treatment process. In this study, copper nanoclusters (Cu NCs) were synthesized via a one-pot method using ammonium citrate as the reducing agent. Cu NCs exhibited bright blue fluorescence, good optical properties and outstanding photostability. The produced Cu NCs were characterized in detail by UV‒vis absorption, fluorescence spectroscopy and transmission electron microscopy (TEM). The produced Cu NCs showed a high quantum yield of 0.97. A fluorescence system was used for doxorubicin (DOX) determination using Cu NCs as a nanoprobe. The presence of DOX decreased the fluorescence intensity of the CuNCs at 445 nm but increased the fluorescence intensity of the CuNCs at 619 nm. As a result, quantitative detection of DOX can be achieved by measuring the ratio of fluorescence intensities at 445 and 619 nm (F619/F445). The fluorescence quenching activity of the Cu NCs was determined to have a linear relationship with the amount of DOX anticancer drug in the range of 1-15 ppb, and the usability of the Cu NCs as a sensor for detection in biological fluids was demonstrated. It was determined that this method can be used to measure the amount of DOX in biological samples effectively.

Complex formation of ML324, the histone demethylase inhibitor, with essential metal ions: Relationship between solution chemistry and anticancer activity

N-(3-(dimethylamino)propyl-4-(8-hydroxyquinolin-6-yl)benzamide (ML324, HL) is a potent inhibitor of the iron-containing histone demethylase KDM4, a recognized potential target of cancer therapeutics. Herein, we report the proton dissociation and complex formation processes of ML324 with essential metal ions such as Fe(II), Fe(III), Cu(II) and Zn(II) using UV-visible, fluorescence, electron paramagnetic resonance and 1H NMR spectroscopic methods. The electrochemical behaviour of the copper and iron complexes was characterized by cyclic voltammetry and spectroelectrochemistry. The solid phase structure of ML324 analysed by X-ray crystallography is also provided. Based on the solution equilibrium data, ML324 is present in solution in H2L+ form with a protonated dimethylammonium moiety at pH 7.4, and this (N,O) donor bearing ligand forms mono and bis complexes with all the studied metal ions and the tris-ligand species is also observed with Fe(III). At pH 7.4 the metal binding ability of ML324 follows the order: Fe(II) < Zn(II) < Cu(II) < Fe(III). Complexation with iron resulted in a negative redox potential (E'1/2 = -145 mV vs. NHE), further suggesting that the ligand has a preference for Fe(III) over Fe(II). ML324 was tested for its anticancer activity in chemosensitive and resistant human cancer cells overexpressing the efflux pump P-glycoprotein. ML324 exerted similar activity in all tested cells (IC50 = 1.9-3.6 μM). Co-incubation and complexation of the compound with Cu(II) and Zn(II) had no impact on the cytotoxicity of ML324, whereas Fe(III) decreased the toxicity in a concentration-dependent manner, and this effect was more pronounced in the multidrug resistant cells.

Cuproptosis in lung cancer: mechanisms and therapeutic potential

Cuproptosis, a recently identified form of cell death that differs from other forms, is induced by the disruption of the binding of copper to mitochondrial respiratory acylation components. Inducing cell cuproptosis and targeting cell copper death pathways are considered potential directions for treating tumor diseases. We have provided a detailed introduction to the metabolic process of copper. In addition, this study attempts to clarify and summarize the relationships between cuproptosis and therapeutic targets and signaling pathways of lung cancer. This review aims to summarize the theoretical achievements for translating the results of lung cancer and cuproptosis experiments into clinical treatment.

Copper in colorectal cancer: From copper-related mechanisms to clinical cancer therapies

Copper, a trace element and vital cofactor, plays a crucial role in the maintenance of biological functions. Recent evidence has established significant correlations between copper levels, cancer development and metastasis. The strong redox-active properties of copper offer both benefits and disadvantages to cancer cells. The intestinal tract, which is primarily responsible for copper uptake and regulation, may suffer from an imbalance in copper homeostasis. Colorectal cancer (CRC) is the most prevalent primary cancer of the intestinal tract and is an aggressive malignant disease with limited therapeutic options. Current research is primarily focused on the relationship between copper and CRC. Innovative concepts, such as cuproplasia and cuproptosis, are being explored to understand copper-related cellular proliferation and death. Cuproplasia is the regulation of cell proliferation that is mediated by both enzymatic and nonenzymatic copper-modulated activities. Whereas, cuproptosis refers to cell death induced by excess copper via promoting the abnormal oligomerisation of lipoylated proteins within the tricarboxylic acid cycle, as well as by diminishing the levels of iron-sulphur cluster proteins. A comprehensive understanding of copper-related cellular proliferation and death mechanisms offers new avenues for CRC treatment. In this review, we summarise the evolving molecular mechanisms, ranging from abnormal intracellular copper concentrations to the copper-related proteins that are being discovered, and discuss the role of copper in the pathogenesis, progression and potential therapies for CRC. Understanding the relationship between copper and CRC will help provide a comprehensive theoretical foundation for innovative treatment strategies in CRC management.

Serum trace elements during treatment in pancreatic cancer patients and their associations with cancer prognosis

BACKGROUND & AIMS

In this study, we assessed serum trace element concentrations in patients with pancreatic cancer and compared the results to those of healthy controls and patients with chronic pancreatitis. We evaluated the association between trace element concentrations during cancer treatment and the risk of cancer progression and mortality in pancreatic cancer patients.

METHODS

A retrospective cohort study was conducted at a tertiary center in Korea. Serum trace element concentrations of cobalt (Co), copper (Cu), selenium (Se), and zinc (Zn) were measured at diagnosis using an inductively coupled plasma-mass spectrometry in 124 patients with pancreatic cancer, 50 patients with chronic pancreatitis, and 120 healthy controls. Trace elements were measured after a median of 282.5 (95% confidence interval [CI], 224.0-326.5) days from treatment initiation to assess changes in trace element concentrations during treatment.

RESULTS

Serum Co concentrations were significantly higher in patients with chronic pancreatitis and pancreatic cancer compared to healthy controls, while serum Se concentrations were significantly lower. During treatment, serum concentrations of Cu, Se, and Zn significantly decreased in patients with pancreatic cancer. During the follow-up (median 152.5; 95% CI, 142.8-160.0 months), 85.5% of patients experienced progression or relapse, and 84.7% of patients died. Patients with decreased Se and Zn concentrations during treatment had a higher mortality (hazard ratio [HR], 2.10; 95% CI, 1.31-3.38; P = 0.0020 for Se; HR, 1.72; 95% CI, 1.06-2.79; P = 0.0269 for Zn) compared to those with unchanged or increased trace element concentrations during treatment. Patients with a greater reduction in Zn concentrations during treatment had a higher mortality than those with a smaller reduction (HR, 1.59; 95% CI, 1.01-2.52; P = 0.0483). Patients whose Zn status changed from normal to deficient during treatment had an increased mortality (HR, 1.76; 95% CI, 1.16-2.67, P = 0.0084). Patients with multiple (≥2) trace element deficiencies after treatment had poorer outcomes than those with no or single trace element deficiency.

CONCLUSIONS

This study revealed that decreases in Se and Zn concentrations during cancer treatment were associated with adverse outcomes in terms of cancer progression and mortality in patients with pancreatic cancer. Further prospective investigations are recommended.

Modulation of Metal Homeostasis for Cancer Therapy

Metal ions such as iron, zinc, copper, manganese, and calcium are essential for normal cellular processes, including DNA synthesis, enzyme activity, cellular signaling, and oxidative stress regulation. When the balance of metal homeostasis is disrupted, it can lead to various pathological conditions, including cancer. Thus, understanding the role of metal homeostasis in cancer has led to the development of anti-tumor strategies that specifically target the metal imbalance. Up to now, diverse small molecule-based chelators, ionophores, metal complexes, and metal-based nanomaterials have been developed to restore the normal balance of metals or exploit the dysregulation for therapeutic purposes. They hold great promise in inhibiting tumor growth, preventing metastasis, and enhancing the effectiveness of existing cancer therapies. In this review, we aim to provide a comprehensive summary of the strategies employed to modulate the homeostasis of iron, zinc, copper, manganese, and calcium for cancer therapy. Their modulation mechanisms for metal homeostasis are succinctly described, and their recent applications in the field of cancer therapy are discussed. At the end, the limitations of these approaches are addressed, and potential avenues for future developments are explored.

Copper homeostasis dysregulation in respiratory diseases: a review of current knowledge

Cu is an essential micronutrient for various physiological processes in almost all human cell types. Given the critical role of Cu in a wide range of cellular processes, the local concentrations of Cu and the cellular distribution of Cu transporter proteins in the lung are essential for maintaining a steady-state internal environment. Dysfunctional Cu metabolism or regulatory pathways can lead to an imbalance in Cu homeostasis in the lungs, affecting both acute and chronic pathological processes. Recent studies have identified a new form of Cu-dependent cell death called cuproptosis, which has generated renewed interest in the role of Cu homeostasis in diseases. Cuproptosis differs from other known cell death pathways. This occurs through the direct binding of Cu ions to lipoylated components of the tricarboxylic acid cycle during mitochondrial respiration, leading to the aggregation of lipoylated proteins and the subsequent downregulation of Fe-S cluster proteins, which causes toxic stress to the proteins and ultimately leads to cell death. Here, we discuss the impact of dysregulated Cu homeostasis on the pathogenesis of various respiratory diseases, including asthma, chronic obstructive pulmonary disease, idiopathic interstitial fibrosis, and lung cancer. We also discuss the therapeutic potential of targeting Cu. This study highlights the intricate interplay between copper, cellular processes, and respiratory health. Copper, while essential, must be carefully regulated to maintain the delicate balance between necessity and toxicity in living organisms. This review highlights the need to further investigate the precise mechanisms of copper interactions with infections and immune inflammation in the context of respiratory diseases and explore the potential of therapeutic strategies for copper, cuproptosis, and other related effects.

Keratin/Copper Complex Electrospun Nanofibers for Antibacterial Treatments: Property Investigation and In Vitro Response

The frontiers of antibacterial materials in the biomedical field are constantly evolving since infectious diseases are a continuous threat to human health. In this work, waste-wool-derived keratin electrospun nanofibers were blended with copper by an optimized impregnation procedure to fabricate antibacterial membranes with intrinsic biological activity, excellent degradability and good cytocompatibility. The keratin/copper complex electrospun nanofibers were multi-analytically characterized and the main differences in their physical-chemical features were related to the crosslinking effect caused by Cu2+. Indeed, copper ions modified the thermal profiles, improving the thermal stability (evaluated by differential scanning calorimetry and thermogravimetry), and changed the infrared vibrational features (determined by infrared spectroscopy) and the chemical composition (studied by an X-ray energy-dispersive spectroscopy probe and optical emission spectrometry). The copper impregnation process also affected the morphology, leading to partial nanofiber swelling, as evidenced by scanning electron microscopy analyses. Then, the membranes were successfully tested as antibacterial materials against gram-negative bacteria, Escherichia coli. Regarding cytocompatibility, in vitro assays performed with L929 cells showed good levels of cell adhesion and proliferation (XTT assay), and no significant cytotoxic effect, in comparison to bare keratin nanofibers. Given these results, the material described in this work can be suitable for use as antibiotic-free fibers for skin wound dressing or membranes for guided tissue regeneration.

Copper-mediated siRNA activation for conditional control of gene expression

Copper plays a crucial role in maintaining biological redox balance in living organisms, with elevated levels observed in cancer cells. Short interfering RNAs (siRNAs) are effective in gene silencing and find applications as both research tools and therapeutic agents. A method to regulate RNA interference using copper is especially advantageous for cancer-specific therapy. We present a chemical approach of selective siRNA activation triggered by intracellular copper ions. We designed and synthesized nucleotides containing copper-responsive moieties, which were incorporated into siRNAs. These copper-responsive siRNAs effectively silenced the target cyclin B1 mRNA in living cells. This pioneering study introduces a novel method for conditionally controlling gene silencing using biologically relevant metal ions in human cells, thereby expanding the repertoire of chemical knockdown tools.

Machine-learning developed an iron, copper, and sulfur-metabolism associated signature predicts lung adenocarcinoma prognosis and therapy response

BACKGROUND

Previous studies have largely neglected the role of sulfur metabolism in LUAD, and no study has combine iron, copper, and sulfur-metabolism associated genes together to create prognostic signatures.

METHODS

This study encompasses 1564 LUAD patients, 1249 NSCLC patients, and over 10,000 patients with various cancer types from diverse cohorts. We employed the R package ConsensusClusterPlus to separate patients into different ICSM (Iron, Copper, and Sulfur-Metabolism) subtypes. Various machine-learning methods were utilized to develop the ICSMI. Enrichment analyses were conducted using ClusterProfiler and GSVA, while IOBR quantified immune cell infiltration. GISTIC2.0 and maftools were utilized for CNV and SNV data analysis. The Oncopredict package predicted drug information based on GDSC1. TIDE algorithm and cohorts GSE91061 and IMvigor210 evaluated patient response to immunotherapy. Single-cell data was processed using the Seurat package, AUCell package calculated cells geneset activity scores, and the Scissor algorithm identified ICSMI-associated cells. In vitro experiments was conducted to explore the role of ICSMRGs in LUAD.

RESULTS

Unsupervised clustering identified two distinct ICSM subtypes of LUAD, each with unique clinical characteristics. The ICSMI, comprising 10 genes, was constructed using integrated machine-learning methods. Its prognostic power was validated in 10 independent datasets, revealing that LUAD patients with higher ICSMI levels had poorer prognoses. Furthermore, ICSMI demonstrated superior predictive abilities compared to 102 previously published signatures. A nomogram incorporating ICSMI and clinical features exhibited high predictive performance. ICSMI positively correlated with patients gene mutations, and integrated analysis of bulk and single-cell transcriptome data revealed its association with TME modulators. Cells representing the high-ICSMI phenotype exhibited more malignant features. LUAD patients with high ICSMI levels exhibited sensitivity to chemotherapy and targeted therapy but displayed resistance to immunotherapy. In a comprehensive analysis across various cancers, ICSMI retained significant prognostic value and emerged as a risk factor for the majority of cancer patients.

CONCLUSIONS

ICSMI provides critical prognostic insights for LUAD patients, offering valuable insights into the tumor microenvironment and predicting treatment responsiveness.

Integrative analysis of the cuproptosis-related gene ATP7B in the prognosis and immune infiltration of IDH1 wild-type glioma

Glioma is the most common malignant tumor in the brain and the central nervous system with a poor prognosis, and wild-type isocitrate dehydrogenase (IDH) glioma indicates a worse prognosis. Cuproptosis is a recently discovered form of cell death regulated by copper-dependent mitochondrial respiration. However, the effect of cuproptosis on tumor prognosis and immune infiltration is not clear. In this research, we analyzed of public databases to show the correlation between cuproptosis-related genes and the prognosis of IDH1 wild-type glioma. Nine out of 12 genes were upregulated in IDH1 wild-type glioma patients, and 6 genes were significantly associated with overall survival (OS), while 5 genes were associated with progression-free survival (PFS). Then, we constructed a prognostic cuproptosis-related gene signature for IDH1 wild-type glioma patients. ATP7B was considered an independent prognostic indicator, and a low expression level of ATP7B was related to a shorter period of OS and PFS. Moreover, downregulation of ATP7B was correlated not only with the infiltration of activated NK cells, CD8 + T cells and M2 macrophages; but also with high expression of immune checkpoint genes and tumor mutation burden (TMB). In the IDH1 wild-type glioma tissues we collected, our data also confirmed that high tumor grade was accompanied by low expression of ATP7B and high expression of PD-L1, which was associated with increasing infiltration of CD8 + immune cells. In conclusion, our research constructed a prognostic cuproptosis-related gene signature model to predict the prognosis of IDH1 wild-type glioma. ATP7B is deemed to be a potential prognostic indicator and novel immunotherapy biomarker for IDH1 wild-type glioma patients.

Quest for a stable Cu-ligand complex with a high catalytic activity to produce reactive oxygen species

Metal ion-catalyzed overproduction of reactive oxygen species (ROS) is believed to contribute significantly to oxidative stress and be involved in several biological processes, from immune defense to development of diseases. Among the essential metal ions, copper is one of the most efficient catalysts in ROS production in the presence of O2 and a physiological reducing agent such as ascorbate. To control this chemistry, Cu ions are tightly coordinated to biomolecules. Free or loosely bound Cu ions are generally avoided to prevent their toxicity. In the present report, we aim to find stable Cu-ligand complexes (Cu-L) that can efficiently catalyze the production of ROS in the presence of ascorbate under aerobic conditions. Thermodynamic stability would be needed to avoid dissociation in the biological environment, and high ROS catalysis is of interest for applications as antimicrobial or anticancer agents. A series of Cu complexes with the well-known tripodal and tetradentate ligands containing a central amine linked to three pyridyl-alkyl arms of different lengths were investigated. Two of them with mixed arm length showed a higher catalytic activity in the oxidation of ascorbate and subsequent ROS production than Cu salts in buffer, which is an unprecedented result. Despite these high catalytic activities, no increased antimicrobial activity toward Escherichia coli or cytotoxicity against eukaryotic AGS cells in culture related to Cu-L-based ROS production could be observed. The potential reasons for discrepancy between in vitro and in cell data are discussed.

The crosstalk between mitochondrial quality control and metal-dependent cell death

Mitochondria are the centers of energy and material metabolism, and they also serve as the storage and dispatch hubs of metal ions. Damage to mitochondrial structure and function can cause abnormal levels and distribution of metal ions, leading to cell dysfunction and even death. For a long time, mitochondrial quality control pathways such as mitochondrial dynamics and mitophagy have been considered to inhibit metal-induced cell death. However, with the discovery of new metal-dependent cell death including ferroptosis and cuproptosis, increasing evidence shows that there is a complex relationship between mitochondrial quality control and metal-dependent cell death. This article reviews the latest research results and mechanisms of crosstalk between mitochondrial quality control and metal-dependent cell death in recent years, as well as their involvement in neurodegenerative diseases, tumors and other diseases, in order to provide new ideas for the research and treatment of related diseases.

Dendritic Pyridine-Imine Copper Complexes as Metallo-Drugs

Since the discovery of cisplatin in the 1960s, the search for metallo-drugs that are more efficient than platinum complexes with negligible side effects has attracted much interest. Among the other metals that have been examined for potential applications as anticancer agents is copper. The interest in copper was recently boosted by the discovery of cuproptosis, a recently evidenced form of cell death mediated by copper. However, copper is also known to induce the proliferation of cancer cells. In view of these contradictory results, there is a need to find the most suitable copper chelators, among which Schiff-based derivatives offer a wide range of possibilities. Gathering several metal complexes in a single, larger entity may provide enhanced properties. Among the nanometric objects suitable for such purpose are dendrimers, precisely engineered hyperbranched macromolecules, which are outstanding candidates for improving therapy and diagnosis. In this review article, we present an overview of the use of a particular Schiff base, namely pyridine-imine, linked to the surface of dendrimers, suitable for complexing copper, and the use of such dendrimer complexes in biology, in particular against cancers.

Monitoring the Mitochondrial Viscosity Changes During Cuproptosis with Iridium(III) Complex Probe via In Situ Phosphorescence Lifetime Imaging

Cuproptosis is a novel copper-dependent form of programmed cell death, displaying important regulatory functions in many human diseases, including cancer. However, the relationship between the changes in mitochondrial viscosity, a key factor associated with cellular malfunction, and cuproptosis is still unclear. Herein, we prepared a phosphorescent iridium (Ir) complex probe for precisely monitoring the changes of mitochondrial viscosity during cuprotosis via phosphorescence lifetime imaging. The Ir complex probe possessed microsecond lifetimes (up to 1 μs), which could be easily distinguished from cellular autofluorescence to improve the imaging contrast and sensitivity. Benefiting from the long phosphorescence lifetime, excellent viscosity selectivity, and mitochondrial targeting abilities, the Ir complex probe could monitor the increase in the mitochondrial viscosity during cuproptosis (from 46.8 to 68.9 cP) in a quantitative manner. Moreover, through in situ fluorescence imaging, the Ir complex probe successfully monitored the increase in viscosity in zebrafish treated with lipopolysaccharides or elescolomol-Cu2+, which were well-known cuproptosis inducers. We anticipate that this new Ir complex probe will be a useful tool for in-depth understanding of the biological effects of mitochondrial viscosity during cuproptosis.

Intelligent nanoreactor coupling tumor microenvironment manipulation and H2O2-dependent photothermal-chemodynamic therapy for accurate treatment of primary and metastatic tumors

Tumor microenvironment (TME), as the "soil" of tumor growth and metastasis, exhibits significant differences from normal physiological conditions. However, how to manipulate the distinctions to achieve the accurate therapy of primary and metastatic tumors is still a challenge. Herein, an innovative nanoreactor (AH@MBTF) is developed to utilize the apparent differences (copper concentration and H2O2 level) between tumor cells and normal cells to eliminate primary tumor based on H2O2-dependent photothermal-chemodynamic therapy and suppress metastatic tumor through copper complexation. This nanoreactor is constructed using functionalized MSN incorporating benzoyl thiourea (BTU), triphenylphosphine (TPP), and folic acid (FA), while being co-loaded with horseradish peroxidase (HRP) and its substrate ABTS. During therapy, the BTU moieties on AH@MBTF could capture excessive copper (highly correlated with tumor metastasis), presenting exceptional anti-metastasis activity. Simultaneously, the complexation between BTU and copper triggers the formation of cuprous ions, which further react with H2O2 to generate cytotoxic hydroxyl radical (•OH), inhibiting tumor growth via chemodynamic therapy. Additionally, the stepwise targeting of FA and TPP guides AH@MBTF to accurately accumulate in tumor mitochondria, containing abnormally high levels of H2O2. As a catalyst, HRP mediates the oxidation reaction between ABTS and H2O2 to yield activated ABTS•+. Upon 808 nm laser irradiation, the activated ABTS•+ performs tumor-specific photothermal therapy, achieving the ablation of primary tumor by raising the tissue temperature. Collectively, this intelligent nanoreactor possesses profound potential in inhibiting tumor progression and metastasis.

Current state of research on copper complexes in the treatment of breast cancer

Breast cancer, a malignancy originating from the epithelium or ductal epithelium of the breast, is not only highly prevalent in women but is also the leading cause of cancer-related deaths in women worldwide. Research has indicated that breast cancer incidence is increasing in younger women, prompting significant interest from scientists actively researching breast cancer treatment. Copper is highly accumulated in breast cancer cells, leading to the development of copper complexes that cause immunogenic cell death, apoptosis, oxidative stress, redox-mediated cell death, and autophagy by regulating the expression of key cell death proteins or assisting in the onset of cell death. However, they have not yet been applied to clinical therapy due to their solubility in physiological buffers and their different and unpredictable mechanisms of action. Herein, we review existing relevant studies, summarize the detailed mechanisms by which they exert anti-breast cancer effects, and propose a potential mechanism by which copper complexes may exert antitumor effects by causing copper death in breast cancer cells. Since copper death in breast cancer is closely related to prognosis and immune infiltration, further copper complex research may provide an opportunity to mitigate the high incidence and mortality rates associated with breast cancer.

Copper metabolism and cuproptosis in human malignancies: Unraveling the complex interplay for therapeutic insights

Copper, a vital trace element, orchestrates diverse cellular processes ranging from energy production to antioxidant defense and angiogenesis. Copper metabolism and cuproptosis are closely linked in the context of human diseases, with a particular focus on cancer. Cuproptosis refers to a specific type of copper-mediated cell death or copper toxicity triggered by disruptions in copper metabolism within the cells. This phenomenon encompasses a spectrum of mechanisms, such as oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress, and perturbations in metal ion equilibrium. Mechanistically, cuproptosis is driven by copper binding to the lipoylated enzymes within the tricarboxylic acid (TCA) cycle. This interaction participates in protein aggregation and proteotoxic stress, ultimately culminating in cell death. Targeting copper metabolism and its associated pathways in cancer cells hold therapeutic potential by selectively targeting and eliminating cancerous cells. Strategies to modulate copper levels, enhance copper excretion, or interfere with cuproptotic pathways are being explored to identify novel therapeutic targets for cancer therapy and improve patient outcomes. Understanding the relationship between cuproptosis and copper metabolism in human malignancies remains an active area of research. This review provides a comprehensive overview of the association among copper metabolism, copper homeostasis, and carcinogenesis, explicitly emphasizing the cuproptosis mechanism and its implications for cancer pathogenesis. Additionally, we emphasize the therapeutic aspects of targeting copper and cuproptosis for cancer treatment.

Molybdenum-Copper Antagonism In Metalloenzymes And Anti-Copper Therapy

The connection between 3d (Cu) and 4d (Mo) via the "Mo-S-Cu" unit is called Mo-Cu antagonism. Biology offers case studies of such interactions in metalloproteins such as Mo/Cu-CO Dehydrogenases (Mo/Cu-CODH), and Mo/Cu Orange Protein (Mo/Cu-ORP). The CODH significantly maintains the CO level in the atmosphere below the toxic level by converting it to non-toxic CO2 for respiring organisms. Several models were synthesized to understand the structure-function relationship of these native enzymes. However, this interaction was first observed in ruminants, and they convert molybdate (MoO4 2- ) into tetrathiomolybdate (MoS4 2- ; TTM), reacting with cellular Cu to yield biological unavailable Mo/S/Cu cluster, then developing Cu-deficiency diseases. These findings inspire the use of TTM as a Cu-sequester drug, especially for treating Cu-dependent human diseases such as Wilson diseases (WD) and cancer. It is well known that a balanced Cu homeostasis is essential for a wide range of biological processes, but negative consequence leads to cell toxicity. Therefore, this review aims to connect the Mo-Cu antagonism in metalloproteins and anti-copper therapy.

Integrative Co-Registration of Elemental Imaging and Histopathology for Enhanced Spatial Multimodal Analysis of Tissue Sections through TRACE

Summary

Elemental imaging provides detailed profiling of metal bioaccumulation, offering more precision than bulk analysis by targeting specific tissue areas. However, accurately identifying comparable tissue regions from elemental maps is challenging, requiring the integration of hematoxylin and eosin (H&E) slides for effective comparison. Facilitating the streamlined co-registration of Whole Slide Images (WSI) and elemental maps, TRACE enhances the analysis of tissue regions and elemental abundance in various pathological conditions. Through an interactive containerized web application, TRACE features real-time annotation editing, advanced statistical tools, and data export, supporting comprehensive spatial analysis. Notably, it allows for comparison of elemental abundances across annotated tissue structures and enables integration with other spatial data types through WSI co-registration.

Availability and Implementation

Available on the following platforms- GitHub: jlevy44/trace_app , PyPI: trace_app , Docker: joshualevy44/trace_app , Singularity: joshualevy44/trace_app .

Contact

joshua.levy@cshs.org.

Supplementary information

Supplementary data are available.

Dietary intake and serum levels of copper and zinc and risk of hepatocellular carcinoma: A matched case-control study

BACKGROUND

Copper and zinc are involved in the development of multiple malignancies; yet, epidemiological evidence on hepatocellular carcinoma (HCC) is limited. This study aimed to investigate the association between dietary intake and serum levels of copper and zinc with the risk of HCC.

METHODS

A total of 434 case-control pairs matched for sex and age (±1 year) were included in this study. Cases with newly diagnosed HCC were from the Guangdong Liver Cancer Cohort (GLCC) study, and healthy controls were from the Guangzhou Nutrition and Health Study (GNHS). A semi-quantitative 79-item food frequency questionnaire (FFQ) was used to assess habitual dietary intakes of copper and zinc. Serum levels of copper and zinc were measured by using inductively coupled plasma mass spectrometry. The copper (Cu)/ zinc (Zn) ratio was computed by dividing copper levels by zinc levels. Conditional logistic regression models were performed to calculate the odds ratio (OR) and 95% confidence intervals (CI) for per 1 standard deviation increase (per-SD increase) in copper and zinc levels.

RESULTS

Higher dietary intake (OR per-SD increase = 0.65, 95% CI: 0.44, 0.96, Ptrend = 0.029) and serum levels of zinc (OR per-SD increase = 0.11, 95% CI: 0.04, 0.30, Ptrend <0.001) were both associated with a lower risk of HCC. Subgroup analyses showed that the inverse association was only pronounced in men but not in women ( Pinteraction = 0.041 for dietary zinc intake and 0.010 for serum zinc levels). Serum copper levels (OR per-SD increase = 2.05, 95% CI: 1.39, 3.03, Ptrend = 0.020) and serum Cu/Zn ratio (OR per-SD increase = 6.53, 95% CI: 2.52, 16.92, Ptrend <0.001) were positively associated with HCC risk, while dietary copper intake and dietary Cu/Zn ratio were not associated with HCC risk.

CONCLUSION

Zinc may be a protective factor for HCC, especially among men, but the effects of copper on HCC risk are not clear.

Normal physiological distribution and tumor localization of 64 CuCl 2 in different human malignancies along with semiquantitative scoring: a comparative evaluation with 18 Fluorodeoxyglucose ( 18 FDG) PET-CT

OBJECTIVE

This study aimed to explore 64-Copper-Chloride ( 64 CuCl 2 ) PET-CT in various malignancies and demonstrate a head-to-head comparison of uptake on 64 CuCl 2 PET/computed tomography (CT) and 18 fluorodeoxyglucose ( 18 FDG)-PET/CT scans for different malignancies, with an emphasis on 18 FDG nonavid malignancies.

METHODS

Fifty-three patients diagnosed with various biopsy-proven malignancies (except prostate cancer) were recruited in this prospective study. All the patients underwent both 64 CuCl 2 PET/CT and 18 FDG-PET/CT. 64 CuCl 2 PET/CT was acquired at 1, 3 and 24 h time points. We studied the physiological biodistribution of 64 CuCl 2 in the various organs, corroborated the uptake of 64 CuCl 2 with various types of malignancies and comparison of their uptake with 18 FDG-PET/CT and their correlation with each other in various lesions.

RESULTS

The biodistribution study showed that the liver concentrated 64 CuCl 2 the most out of all the organs, followed by the pancreas and large intestine. Liver and intestinal activity increased subsequently with delayed imaging, and the washout of 64 CuCl 2 was noted in the pancreas in delayed images and followed a hepatobiliary excretion of tracer over a period of time. In lesion-wise analysis, it was noted that the primary neuroendocrine tumor, melanoma and renal/urothelial malignancy group showed more uptake of 64 CuCl 2 , than that in metastasis and vice-versa was noted in lung and soft tissue malignancies. Comparing it with 18 FDG, it was seen that FDG showed more uptake in lesions and showed no significant correlation (Kappa value: 0.089) with the uptake of 64 CuCl 2 in the lesion-wise comparison.

CONCLUSION

64 CuCl 2 PET/CT did not show any added advantage over 18 FDG-PET/CT in the evaluation of the studied malignancies, both primary and their metastasis. Biodistribution studies showed the liver as the organ with maximum uptake, which implies it may hinder the detection of abdominal or hepatic involvement of the disease.

Assessment of Mononuclear/Dinuclear copper acylhydrazone complexes for lung cancer treatment

Non-platinum metal-based complexes have good potential for cancer treatment. Here, we designed and synthesized five hydrazone copper(II) complexes, [Cu2(HL)2Cl2] 1A, [Cu2(HL)2(NO3)H2O]·NO3 2A, [Cu2(HL)2Br2] 3A, [Cu(L)pyridine] 1B and [Cu(HL)(pyridine)Br] 3B, and evaluated their anti-lung cancer activities. MTT experiments revealed that these copper(II) complexes exhibit higher anticancer activity than cisplatin. Mechanism studies revealed that complex 3A induced G1 phase cell cycle arrest, and induced cell apoptosis via reactive oxygen species (ROS)-mediated mitochondrial dysfunction. Scratch wound healing assay was also performed, revealing that complex 3A have good anti-cell migration activity. Hemolysis assays showed good blood biocompatibility of complex 3A. Furthermore, complex 3A can significantly inhibit the proliferation of A549 3D tumor spheroid. An in vivo anticancer study showed that complex 3A could delays the growth of A549 tumor xenografts with lower systemic toxicity. These results highlight the great possibility of developing highly active copper complexes as anti-lung cancer agents.

Serum copper status of patients with colorectal cancer: A systematic review and meta-analysis

BACKGROUND

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide and a public health problem. Several clinical studies have shown that copper (Cu) is involved in carcinogenesis, possibly via cuproptosis, a new form of programmed cell death, but the conclusions from published reports are inconsistent. This study aimed at evaluating the potential of Cu dysregulation as a CRC susceptibility factor.

METHODS

In this systematic review and meta-analysis, we searched Cochrane Library, EBSCOhost, EMBASE, ProQuest, PubMed/MEDLINE, Scopus, and Web of Science for studies reporting serum Cu concentrations in CRC patients and controls from articles published till June 2023. The studies included reported measurements of serum/plasma/blood Cu levels. Meta-analyses were performed as well as study quality, heterogeneity, and small study effects were assessed. Based on a random effects model, summary standardized mean differences (SMDs) and the corresponding 95% confidence intervals (95% CIs) were applied to compare the levels of Cu between CRC patients and controls.

RESULTS

26 studies with a pooled total of9628 participants and 2578 CRC cases were included. The pooled SMD was equal to 0.85 (95% CIs -0.44; 2.14) showing that the CRC patients had higher mean Cu levels than the control subjects, but the difference was not significant (p = 0.185) and the heterogeneity was very high, I2 = 97.9% (95% CIs: 97.5-98.3%; p < 0.001).

CONCLUSION

The pooled results were inconclusive, likely due to discordant results and inaccuracy in reporting data of some studies; further research is needed to establish whether Cu dysregulation might contribute to the CRC risk and whether it might reflect different CRC grades.

Recently Reported Biological Activities and Action Targets of Pt(II)- and Cu(II)-Based Complexes

Most diseases that affect human beings across the world are now treated with drugs of organic origin. However, some of these are associated with side effects, toxicity, and resistance phenomena. For the treatment of many illnesses, the development of new molecules with pharmacological potential is now an urgent matter. The biological activities of metal complexes have been reported to have antitumor, antimicrobial, anti-inflammatory, anti-infective and antiparasitic effects, amongst others. Metal complexes are effective because they possess unique properties. For example, the complex entity possesses the effective biological activity, then the formation of coordination bonds between the metal ions and ligands is controlled, metal ions provide it with extraordinary mechanisms of action because of characteristics such as d-orbitals, oxidation states, and specific orientations; metal complexes also exhibit good stability and good physicochemical properties such as water solubility. Platinum is a transition metal widely used in the design of drugs with antineoplastic activities; however, platinum is associated with side effects which have made it necessary to search for, and design, novel complexes based on other metals. Copper is a biometal which is found in living systems; it is now used in the design of metal complexes with biological activities that have demonstrated antitumoral, antimicrobial and anti-inflammatory effects, amongst others. In this review, we consider the open horizons of Cu(II)- and Pt(II)-based complexes, new trends in their design, their synthesis, their biological activities and their targets of action.

Bioinformatic analysis and experimental validation of cuproptosis-related LncRNA as a novel biomarker for prognosis and immunotherapy of oral squamous cell carcinoma

BACKGROUND

The novel form of regulatory cell death, cuproptosis, is characterized by proteotoxicity, which ultimately leads to cell death. Its targeting has emerged as a promising therapeutic approach for oral squamous cell carcinoma (OSCC). Long noncoding RNAs (lncRNAs) participate in epigenetic regulation and have been linked to the progression, prognosis, and treatment of OSCC. Thus, this study aimed to identify new cuproptosis-related lncRNAs (CRLs), establish predictive models for clinical prognosis, immune response, and drug sensitivity, and provide novel insights into immune escape and tumor drug resistance.

METHODS

The present study screened eight CRLs (THAP9-AS1, STARD4-AS1, WDFY3-AS2, LINC00847, CDKN2A-DT, AL132800.1, GCC2-AS1, AC005746.1) using Lasso Cox regression analysis to develop an eight-CRL prognostic model. Patients were categorized into high- and low-risk groups using risk scores. To evaluate the predictive ability of the model, Kaplan-Meier analysis, ROC curves, and nomograms were employed. Furthermore, the study investigated the differences in immune function and anticancer drug sensitivity between the high- and low-risk groups. To validate the expression of CRLs in the model, OSCC cell lines were subjected to quantitative real-time fluorescence PCR (qRT-PCR).

RESULTS

The results of the study showed that the high-risk group had a shorter overall survival (OS) time in OSCC patients. Cox regression analysis demonstrated that the high-risk score was an independent risk factor for a poor prognosis. The validity of the model was confirmed using ROC curve analysis, and a nomogram was developed to predict the prognosis of OSCC patients. Furthermore, patients in the high-risk group with high TMB had a poorer prognosis. Patients in the low-risk group responded better to immunotherapy than those in the high-risk group. Additionally, the risk scores were significantly associated with drug sensitivity in OSCC patients. Finally, the findings of qRT-PCR supported the reliability of the proposed risk model.

CONCLUSION

The study identified and established the 8-CRL model, which represents a novel pathway of lncRNA regulation of cuproptosis in OSCC. This model provides guidance for the prognosis and treatment of OSCC and offers a new insight into immune escape and tumor drug resistance.

Different Valence States of Copper Ion Delivery against Triple-Negative Breast Cancer

Different valence states of copper (Cu) ions are involved in complicated redox reactions in vivo, which are closely related to tumor proliferation and death pathways, such as cuproptosis and chemodynamic therapy (CDT). Cu ion mediated Fenton-like reagents induced tumor cell death which presents compelling attention for the CDT of tumors. However, the superiority of different valence states of Cu ions in the antitumor effect is unknown. In this study, we investigated different valence states of Cu ions in modulating tumor cell death by Cu-chelated cyanine dye against triple-negative breast cancer. The cuprous ion (Cu+) and copper ion (Cu2+) were chelated with four nitrogen atoms of dipicolylethylenediamine-modified cyanine for the construction of Cu+ and Cu2+ chelated cyanine dyes (denoted as CC1 and CC2, respectively). Upon 660 nm laser irradiation, the CC1 or CC2 can generate reactive oxygen species, which could disrupt the cyanine structure, achieving the rapid release of Cu ions and initiating the Fenton-like reaction for CDT. Compared with Cu2+-based Fenton-like reagent, the CC1 with Cu+ exhibited a better therapeutic outcome for the tumor due to there being no need for a reduction by glutathione and a shorter route to generate more hydroxyl radicals. Our findings suggest the precision delivery of Cu+ could achieve highly efficient antitumor therapy.

Current Trends on the Involvement of Zinc, Copper, and Selenium in the Process of Hepatocarcinogenesis

Numerous nutritional factors increase the risk of hepatocellular carcinoma (HCC) development. The dysregulation of zinc, copper, and selenium homeostasis is associated with the occurrence of HCC. The impairment of the homeostasis of these essential trace elements results in oxidative stress, DNA damage, cell cycle progression, and angiogenesis, finally leading to hepatocarcinogenesis. These essential trace elements can affect the microenvironment in HCC. The carrier proteins for zinc and copper and selenium-containing enzymes play important roles in the prevention or progression of HCC. These trace elements enhance or alleviate the chemosensitivity of anticancer agents in patients with HCC. The zinc, copper, or selenium may affect the homeostasis of other trace elements with each other. Novel types of cell death including ferropotosis and cupropotosis are also associated with hepatocarcinogenesis. Therapeutic strategies for HCC that target these carrier proteins for zinc and copper or selenium-containing enzymes have been developed in in vitro and in vivo studies. The use of zinc-, copper- or selenium-nanoparticles has been considered as novel therapeutic agents for HCC. These results indicate that zinc, copper, and selenium may become promising therapeutic targets in patients with HCC. The clinical application of these agents is an urgent unmet requirement. This review article highlights the correlation between the dysregulation of the homeostasis of these essential trace elements and the development of HCC and summarizes the current trends on the roles of these essential trace elements in the pathogenesis of hepatocarcinogenesis.

The role of metal ions in the occurrence, progression, drug resistance, and biological characteristics of gastric cancer

Metal ions exert pivotal functions within the human body, encompassing essential roles in upholding cell structure, gene expression regulation, and catalytic enzyme activity. Additionally, they significantly influence various pathways implicated in divergent mechanisms of cell death. Among the prevailing malignant tumors of the digestive tract worldwide, gastric cancer stands prominent, exhibiting persistent high mortality rates. A compelling body of evidence reveals conspicuous ion irregularities in tumor tissues, encompassing gastric cancer. Notably, metal ions have been observed to elicit distinct contributions to the progression, drug resistance, and biological attributes of gastric cancer. This review consolidates pertinent literature on the involvement of metal ions in the etiology and advancement of gastric cancer. Particular attention is directed towards metal ions, namely, Na, K, Mg, Ca, Fe, Cu, Zn, and Mn, elucidating their roles in the initiation and progression of gastric cancer, cellular demise processes, drug resistance phenomena, and therapeutic approaches.

Structure prediction of physiological bis(amino acidato)copper(II) species in aqueous solution: The copper(II) compounds with l-glutamine and l-histidine

Neutral (l-histidinato)(l-glutaminato)copper(II) [Cu(His)(Gln)] has been established as the most abundant ternary copper(II) amino acid compound of the exchangeable copper(II) pool in blood plasma. The experimental studies of Cu(His)(Gln) and bis(glutaminato)copper(II) [Cu(Gln)2] in solutions did not specify their complete geometries. To determine the geometries, this paper investigates the conformers, energy landscapes, and a structure-magnetic parameters relation of Cu(Gln)2 and Cu(His)(Gln) by the density functional theory (DFT) calculations. We assume a glycine-like coordination of Gln (other coordination patterns are dismissed because of steric reasons), and three His in-plane copper(II) binding modes. The conformational analyses are performed in the gas phase and implicitly modeled aqueous solution. The reliability of the DFT relative electronic and Gibbs free energies of the Cu(His)(Gln) conformers is confirmed by benchmarking against the corresponding energies obtained by the domain-based local pair natural orbital coupled-cluster method with singles, doubles, and perturbative triples [DLPNO-CCSD(T)]. Several cis- and trans-Cu(His)(Gln) conformers with His in the histaminate-like and glycine-like modes have low Gibbs free energies, and the greatest estimated metal-binding affinities. The DFT-calculated magnetic parameters of the low-energy conformers reproduce best the experimental electron paramagnetic resonance parameters measured in aqueous solutions for trans- and cis-Cu(Gln)2 conformers having two oxygen atoms (either from Gln or water molecules) at the apical positions, and Cu(His)(Gln) conformers having His in the histaminate-like mode with an apically placed carboxylato oxygen atom. The predicted conformational flexibility of His‑copper(II)-amino acid compounds may be connected with their physiological abundance, and the role in copper(II) exchange reactions in blood plasma.

Copper overload induces apoptosis and impaired proliferation of T cell in zebrafish

Copper is an essential biometal for cell development and function, however, unbalanced copper homeostasis in T cell development and the underlying mechanisms are largely unexplored. Here, we use a zebrafish model to investigate the effect of copper overload in T cell development. We show that copper stressed zebrafish larvae exhibit a significant reduction in T cells with increased cell apoptosis and impaired cell proliferation. T cell progenitors, hematopoietic stem and progenitor cells, also exhibit increased cell apoptosis. Copper overload induces production of ROS and the down-regulations of its resistance genes foxos, and ectopic expression of foxo3a, ROS scavenger GSH, could both effectively rescue the reduction of T cells in copper overload larvae. Moreover, foxm1-cytoskeleton axis, parallel to ROS-foxo axis, also mediates the copper overload induced T cell developmental defects. Meanwhile, ROS destroys expression of cytoskeleton rather than of foxm1 in the cells to induce cell apoptosis and the impaired proliferation. The functional integrity of copper transporters cox17 and atp7b are required for copper stress in inducing T cell apoptosis and proliferation impairment. Our findings demonstrate that the down-stream ROS-foxo/cytoskeleton and foxm1-cytoskeleton signaling pathways contribute jointly to copper overload induced T cell apoptosis and proliferation defects, which are depend on the integral function of Cox17 and Atp7b, and provide new insight into the copper homeostasis in T lymphocyte development.