Cuproptosis: Revolutionizing Cancer Treatment with Copper's Hidden Potential.

This special issue on Cell Stress and Cell Death is aimed at bringing together recent developments in the fields of cellular stress and cell death and, in particular, the interplay between cell stress responses and cell death. The special issue opens with a review by S. Fulda et al. which provides an overview of how cells can respond to stress in a variety of ways ranging from the activation of survival pathways to the initiation of cell death that eventually eliminates damaged cells. Whether cells mount a protective response or succumb to death depends to a large extent on the nature and duration of the stress as well as the cell type. For example, milder stresses can lead to protection through activation of the heat shock response or the unfolded protein response (UPR). This review also describes several types of cell death (e.g., apoptosis, necrosis, pyroptosis, or autophagic cell death) and the mechanism by which a cell dies often depends on various exogenous factors as well as the cell's ability to handle the stress to which it is exposed. The implications of cellular stress responses for human physiology and disease are multifold and are discussed in this review in the context of some major world health issues such as diabetes, Parkinson's disease, myocardial infarction, and cancer. There are many molecules and cellular processes that play critical roles in normal cell signaling and survival responses, while also having a dual role in inducing cell death. A number of papers in this special issue, covering endoplasmic reticulum (ER) stress and Ca2+, address this topic. In recent years there has been a significant increase in the number of papers in the field dealing with ER stress and ER stress-induced cell death. This reflects the growing recognition of the importance of the ER in cell stress and in different modes of cell death. The ER is the site of folding of membrane and secreted proteins in the cell. Physiological or pathological processes that disturb protein folding in the ER initiate a complex intracellular signal transduction pathway, known as the UPR. This response is an attempt to reestablish ER homeostasis, although it can also lead to cell death. The review by A. Samali et al. provides a comprehensive overview of current methodologies for monitoring the UPR and ER stress, and it puts together a set of criteria to assess this response, which will be useful for researchers who wish to examine these phenomena in different model systems. The UPR is essentially tailored to reestablish ER homeostasis and it can also signal through other adaptive mechanisms involving the stimulation of autophagy. However, when ER stress is persistent, the cytoprotective functions of the UPR and autophagy can switch to cell death-promoting mechanisms. A review by T. Verfaillie et al. discusses the relationship between ER stress and autophagy and the implications for cancer therapy. Recently, a variety of anticancer therapies have been linked to the induction of ER stress in cancer cells, envisaging strategies that stimulate prodeath function or block its prosurvival function, to improve tumoricidial action. A better understanding of the molecular mechanisms that determine the final outcome of UPR and autophagy activation by chemotherapeutic agents will offer new opportunities to improve existing cancer therapies as well as revealing novel targets for cancer treatment. Prolonged or severe ER stress has been linked to induction of apoptosis. Caspase activation is one of the key steps in commitment of cells to apoptosis and is dependent on mitochondrial outer membrane permeabilization (MOMP) and the release of cytochrome c from the mitochondria. The research article by S. Gupta et al. investigates the mechanism of ER stress-induced MOMP using thapsigargin as an inducer of ER stress. They genetically dissected the role of caspase-9, -3, and -2 in the induction of MOMP by ER stress using embryonic fibroblasts derived from knockout mice and also treated cells with chemical and molecular inhibitors of the mitochondrial permeability transition. Their results suggest that caspase-9 and -2, Bcl-2 family members, and the mitochondrial permeability transition pore all play a role in MOMP during ER stress-induced apoptosis. Ca2+ is an important second messenger which is also poised at the intersection between cell survival and cell death. The review by C. Cerella et al. examines the events that occur during Ca2+ toxicity and how reparative or death pathways can be activated. They also discuss the observations that while Ca2+ can elicit these opposing responses, it also plays a role as a second messenger in signal transduction associated with cell death and survival. Knowledge of cell stress and cell death pathways, and the interplay between these, beneficially provides us with new ways to tackle diseases, particularly cancers and degenerative disease. Resistance to apoptosis is a feature of many cancer cells and this is the subject of the review by S. Fulda which summarizes the main mechanisms by which cancer cells evade the intrinsic and extrinsic apoptosis pathways. Generally, altered ratios of key pro- and antiapoptotic proteins are responsible for resistance to cell death; for example, altered ratios of Bcl-2 family proteins as well as increased expression of caspase inhibitors (IAPs) regulate the intrinsic pathway, while reduced sensitivity of extrinsic pathways occurs due to decreased expression of death receptors on the plasma membrane and increased expression of intracellular decoy proteins. Given this increased resistance to cell death pathways, the search for novel molecules to induce cell death in cancer cells is an important goal. Histone deacetylase inhibitors have become a promising new avenue for cancer therapy, and many are currently in clinical trials for various tumor types. The research article by N. Rivera-Del Valle et al. demonstrates that a novel hydroxamic acid histone deacetylase inhibitor, PCI-24781, exerts cytotoxicity and histone alterations in leukemia cells, via a mechanism that is dependent on caspase-8 and Fas-associated death domain. Another avenue for identifying novel therapeutic targets for cancers is study of inflammation, since many human malignancies have been strongly linked with chronic inflammation. The review by C. Sobolewski et al. describes the role of cyclooxygenase-2 in these diseases. This enzyme is a member of a family, which catalyzes the rate-limiting step of prostaglandin biosynthesis. Cyclooxygenase-2 is upregulated during both inflammation and cancer, and has been described to modulate cell proliferation and apoptosis mainly in solid tumors and more recently in hematological malignancies. Thus, the use of cyclooxygenase-2 inhibitors, together with other therapeutic strategies, may further improve the efficiency of anticancer treatments in the clinic. In contrast to cancers, an important aim of research into degenerative diseases is to discover novel ways to inhibit cell death. One such disease is Parkinson's disease, where there are currently no therapies which halt the degeneration of dopaminergic neurons. In the research article by K. Mnich et al. the ability of the endogenous cannabinoid, anandamide, to inhibit apoptotic cell death by the Parkinson mimetic, 6-hydroxydopamine, was shown. The protection provided by anandamide involved activation of phosphatidylinositol 3-kinase and prevention of 6-hydroxydopamine induced activation of c-Jun-NH2-terminal kinase (JNK). These data add to the growing body of literature concerning cannabinoids and Parkinson's disease. Certain other neurodegenerative diseases, termed tauopathies, feature filamentous tau-positive protein inclusions in neurons and glia, which are characterized by the expression of stress response proteins, particularly heat shock proteins (Hsps), in these inclusions. The article by L. Schwarz et al. investigated the contribution of small Hsps, Hsp27, and αB-crystallin, to neurodegenerative diseases by analyzing the association of Hsp27 with pathological lesions of tauopathies. Their results suggest distinct mechanisms for Hsp27 action in glial and neuronal cells, with prominent expression in unstressed astrocytes but with low expression observed in neurons even after stress situations. We hope that this special issue will alert researchers to some new developments in the fields of cell stress and cell death, particularly the interplay between prosurvival and prodeath responses, and how our knowledge of these can direct our efforts in discovering new therapeutic strategies for the treatment of cancers and degenerative diseases. Afshin Samali Simone Fulda Adrienne M. Gorman Osamu Hori Srinivasa M. Srinivasula

Inducers of Autophagy and Cell Death: Focus on Copper Metabolism.

Staphylococcus epidermidis is a skin-resident bacterium and a major cause of biomaterial-associated infections. The transition from residing on the skin to residing on an implanted biomaterial is accompanied by regulatory changes that facilitate bacterial survival in the new environment. These regulatory changes are dependent upon the ability of bacteria to "sense" environmental changes. In S. epidermidis, disparate environmental signals can affect synthesis of the biofilm matrix polysaccharide intercellular adhesin (PIA). Previously, we demonstrated that PIA biosynthesis is regulated by tricarboxylic acid (TCA) cycle activity. The observations that very different environmental signals result in a common phenotype (i.e. increased PIA synthesis) and that TCA cycle activity regulates PIA biosynthesis led us to hypothesize that S. epidermidis is "sensing" disparate environmental signals through the modulation of TCA cycle activity. In this study, we used NMR metabolomics to demonstrate that divergent environmental signals are transduced into common metabolomic changes that are "sensed" by metabolite-responsive regulators, such as CcpA, to affect PIA biosynthesis. These data clarify one mechanism by which very different environmental signals cause common phenotypic changes. In addition, due to the frequency of the TCA cycle in diverse genera of bacteria and the intrinsic properties of TCA cycle enzymes, it is likely the TCA cycle acts as a signal transduction pathway in many bacteria.

Advancements in the CRISPR technology, a game-changer in experimental research, have revolutionized various fields of life sciences and more profoundly, cancer research. Cell death pathways are among the most deregulated in cancer cells and are considered as critical aspects in cancer development. Through decades, our knowledge of the mechanisms orchestrating programmed cellular death has increased substantially, attributed to the revolution of cutting-edge technologies. The heroic appearance of CRISPR systems have expanded the available screening platform and genome engineering toolbox to detect mutations and create precise genome edits. In that context, the precise ability of this system for identification and targeting of mutations in cell death signaling pathways that result in cancer development and therapy resistance is an auspicious choice to transform and accelerate the individualized cancer therapy. The concept of personalized cancer therapy stands on the identification of molecular characterization of the individual tumor and its microenvironment in order to provide a precise treatment with the highest possible outcome and minimum toxicity. This study explored the potential of CRISPR technology in precision cancer treatment by identifying and targeting specific cell death pathways. It showed the promise of CRISPR in finding key components and mutations involved in programmed cell death, making it a potential tool for targeted cancer therapy. However, this study also highlighted the challenges and limitations that need to be addressed in future research to fully realize the potential of CRISPR in cancer treatment.Graphical abstractCurrent application of CRISPR system in cancer therapy through a glance. A choosing the appropriate biological model for screening in vitro (using established cell lines, animal derived tumor cells, human derived tumor cells, stem cells or T cells), in vivo (using animal models which can harbor human derived tumor), or ex vivo (human/animal-derived organoids). B preparation of CRISPR gRNA library. C experimental design of CRISPR screening, identification of the desired gRNAs or phenotypic response. D CRISPR-Cas targeting of the identified targets, with Cas9 gene editing system (Knockout, base editing, prime editing), RNA modulation (modulation of RNA splicing, RNA base editing, RNA interference), and epigenomic edits and CRISPR interference/activation using dead Cas9 (dCas9) (Bock et al. 2022b)

one of the leading causes of mortality worldwide. Cell deaths, especially programmed cell deaths, are critical processes in the development of various CVDs (1). Recently, accumulating studies have shed light on emerging cell death modalities, such as ferroptosis, necroptosis, pyroptosis, PANoptosis, and their relevance to the onset and progression of CVDs (2)(3)(4). A comprehensive understanding and targeted exploration of different types of programmed cell death could provide novel insights for the therapeutic targets of CVDs.Cytokines also play an essential role in CVD development. They are considered to have crucial regulatory roles in CVDs through autocrine, paracrine, and endocrine actions (5,6). For instance, we have previously reported the important roles of IL-10, sST2, and IL-33 in vascular and myocardial diseases (7)(8)(9). Furthermore, many cytokines, such as TNF-α, IL-1β, IL-6, and IL-11 are critically involved in CVD development (6,10). Importantly, pro-inflammatory cytokines, particularly IL-1β, IFNγ and TNF-α can directly initiate the cell death program, such as apoptosis and PANoptosis (11,12). Concurrently, cell death mortalities like pyroptosis and PANoptosis can also promote the release of intracellular components and cytokines, triggering an inflammatory cascade response, thereby contributing to CVDs (13). Research focusing on the crosstalk between cytokines and the cell death pathway may offer novel therapeutic perspectives for heart-related diseases.Building on this, the research topic "Cytokines, Novel Cell Death Models, and Pathways in Cardiovascular Diseases" published in Frontiers in Cardiovascular Medicine aimed to discuss recent advances and offer insights in this field. In conclusion, this special issue of Frontiers in Cardiovascular Medicine sheds light on the intricate interplay between cell death modalities, cytokines, and their involvement in CVDs. It underscores the importance of further researches on the crosstalk between cell death pathways and cytokine regulation, as it holds significant promise for developing more effective preventive and treatment strategies to address the increasing burden of CVDs worldwide. commercial or financial relationships that could be construed as a potential conflict of interest.

Aha! ……. apoptosis: means to an end

Copper (Cu) is a vital trace element required for sustaining life and is involved in numerous critical metabolic processes within the body. Cuproptosis, a newly recognized type of Cu-dependent cell death, is mechanistically distinct from apoptosis, autophagy, pyroptosis, and ferroptosis. It is characterized by abnormal Cu accumulation and aberrant interactions with key enzymes of the tricarboxylic acid (TCA) cycle, which lead to protein aggregation, loss of iron–sulfur cluster proteins, and proteotoxic stress, ultimately leading to cell death. Recent studies have revealed that Cu dyshomeostasis and cuproptosis are intricately linked to the pathological progression of several neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), Huntington’s disease (HD), Wilson’s disease (WD), and Menkes disease (MD). In this review, we systematically elucidate the systemic Cu metabolism, the molecular mechanisms of cuproptosis, and its intricate interplay with different neurodegenerative disorders. We also examined the relationship between cuproptosis and other types of cell death. Finally, we discuss therapeutic strategies targeting cuproptosis and Cu dyshomeostasis to combat neurodegenerative diseases and propose potential directions for future research.

The death of larval salivary gland cells during metamorphosis in Drosophila melanogaster has been a key system for studying steroid controlled programmed cell death. This death is induced by a pulse of the steroid hormone ecdysone that takes place at the end of the prepupal period. For many years, it has been thought that the ecdysone direct response gene Eip93F (E93) plays a critical role in initiating salivary gland cell death. This conclusion was based largely on the finding that the three “type” alleles of E93 cause a near-complete block in salivary gland cell death. Here, we show that these three mutations are in fact allelic to Idh3b, a nearby gene that encodes the β subunit of isocitrate dehydrogenase 3, a mitochondrial enzyme of the tricarboxylic acid (TCA) cycle. The strongest of the Idh3b alleles appears to cause a near-complete block in oxidative phosphorylation, as mitochondria are depolarized in mutant larvae, and development arrests early during cleavage in embryos from homozygous-mutant germline mothers. Idh3b-mutant larval salivary gland cells fail to undergo mitochondrial fragmentation, which normally precedes the death of these cells, and do not initiate autophagy, an early step in the cell death program. These observations suggest a close relationship between the TCA cycle and the initiation of larval cell death. In normal development, tagged Idh3b is released from salivary gland mitochondria during their fragmentation, suggesting that Idh3b may be an apoptogenic factor that functions much like released cytochrome c in mammalian cells.

Copper is an essential nutrient for maintaining enzyme activity and transcription factor function. Excess copper results in the aggregation of lipoylated dihydrolipoamide S-acetyltransferase (DLAT), which correlates to the mitochondrial tricarboxylic acid (TCA) cycle, resulting in proteotoxic stress and eliciting a novel cell death modality: cuproptosis. Cuproptosis exerts an indispensable role in cancer progression, which is considered a promising strategy for cancer therapy. Cancer immunotherapy has gained extensive attention owing to breakthroughs in immune checkpoint blockade; furthermore, cuproptosis is strongly connected to the modulation of antitumor immunity. Thus, a thorough recognition concerning the mechanisms involved in the modulation of copper metabolism and cuproptosis may facilitate improvement in cancer management. This review outlines the cellular and molecular mechanisms and characteristics of cuproptosis and the links of the novel regulated cell death modality with human cancers. We also review the current knowledge on the complex effects of cuproptosis on antitumor immunity and immune response. Furthermore, potential agents that elicit cuproptosis pathways are summarized. Lastly, we discuss the influence of cuproptosis induction on the tumor microenvironment as well as the challenges of adding cuproptosis regulators to therapeutic strategies beyond traditional therapy.

Cell death plays a significant role in the physiology of all living organisms, and its disruption is the underlying cause of various diseases. Previously, it was assumed that apoptosis and necrosis were the only means of cell death. Recent discoveries of alternative cell death pathways highlighted a complicated interplay between cell death regulation and its role in numerous human pathologies. DNA methylation is a universal epigenetic mechanism characterized by the covalent addition of a methyl group to cytosine in CpG dinucleotides. Alterations in DNA methylation patterns lead to the dysregulation of multiple cell death pathways. DNA methylome studies on cell death pathways have improved our understanding of the mechanism of various types of cell death, such as apoptosis, pyroptosis, necroptosis, ferroptosis, anoikis, autophagy, and cuproptosis. The irregular DNA methylation patterns of genes encoding proteins linked to multiple cell death pathways could underlie resistance to cell death. Dysregulation of cell death is linked to ailments in humans, such as cancer. However, unlike genetic alterations, DNA methylation is reversible, making it extremely interesting for therapeutics considering the potential use of DNA methyltransferase inhibitors. Furthermore, tumor microenvironment and genetic heterogeneity of cancers may influence the methylation-dependent regulation of cell death, contributing to tumor progression and therapeutic resistance. Understanding how DNA methylation influences cell death pathways may illuminate the underlying causes of cancer. This review explores the significance of the DNA methylation patterns of key genes involved in cell death pathways, emphasizing their connections and identifying potential gaps that could be exploited for developing epigenetic therapies targeting cancer.

Mitochondria are being recognized as key factors in many unexpected areas of biomedical science. In addition to their well-known roles in oxidative phosphorylation and metabolism, it is now clear that mitochondria are also central to cell death, neoplasia, cell differentiation, the innate immune system, oxygen and hypoxia sensing, and calcium metabolism. Disruption to these processes contributes to a range of human pathologies, making mitochondria a potentially important, but currently seemingly neglected, therapeutic target. Mitochondrial dysfunction is often associated with oxidative damage, calcium dyshomeostasis, defective ATP synthesis, or induction of the permeability transition pore. Consequently, therapies designed to prevent these types of damage are beneficial and can be used to treat many diverse and apparently unrelated indications. Here we outline the biological properties that make mitochondria important determinants of health and disease, and describe the pharmacological strategies being developed to address mitochondrial dysfunction.

Nanotechnology is explained as the science of engineered materials and systems on a molecular scale. This innovation is currently used in a wide variety of applications which include using these nanoparticles as drug delivery vehicles. Such nanocarriers are relatively smaller than 100 nm in size with the ability to convey therapeutic drugs to a number of disease sites. Platinum-based nanoparticles have been extensively used in a number of applications namely catalysts, gas sensors, glucose sensors and cancer therapy. The properties of platinum nanoparticles (PtNP’s) typically depend on characteristics such as shape, particle size, elemental composition and structure, all of which can be manipulated and controlled in the fabrication process. Their unique size in the nanometer scale makes platinum nanoparticles an ideal candidate as targeted drug delivery vehicles. To target an anticancer drug to a diseased site is a distinctive feature of most studies, which aim to transfer an adequate dosage of the drug to cancer cells. Transport systems used as carriers of anticancer drugs offer numerous advantages, which include improved efficacy and a decrease in toxicity towards healthy cells when compared to standard drugs. The aim of this study was to determine the effect of platinum nanoparticles, gemcitabine and gemcitabine conjugated platinum nanoparticles (Hybrids) against cancer cells and healthy cells and to determine the mode of cell death and cell death pathways using flow cytometry. Platinum nanoparticles were synthesized via the reduction of hexachloroplatinic acid using sodium borohydride in the presence of capping agents. Synthesized platinum nanoparticles and the hybrids were characterized by observing peaks at 301 nm and 379 nm respectively using UV-visible spectroscopy. TEM images revealed that the PtNP’s and the conjugate compounds were spherical in shape with core sizes of 1.14 nm - 1.65 nm and 1.53 - 2.66 nm respectively. The bioactivity platinum nanoparticles, gemcitabine and the hybrids were investigated using MCF7 and Melanoma cancer cells at different concentrations from 0.10 to 100 µg/ml. Results indicated that conjugated nanoparticles induced the highest cell inhibition against both cell lines compared to gemcitabine and platinum nanoparticles. Bioactivity against PBMC (peripheral blood mononuclear) cells indicated that all three compounds show little or no effect towards the healthy cell line compared to the control. Melanoma cell line was used to determine the mode of cell death. Apoptosis was detected using Annexin V-FITC to detect membrane changes, JC-1 to detect a loss in mitochondrial membrane potential and caspase-3 assay kits. Results indicated that a significant amount of cell death was caused by cleavage of caspase-3. Nanoparticle drug delivery is an area that has shown significant promise in cancer treatment. Interaction of nanoparticles with human cells is an interesting topic for understanding toxicity and developing potential drug candidates. Imagine, something that is atleast or more than 80,000 times smaller than the edge of the ridge on a fingertip and unlocks a new wilderness into cancer research. Nanotechnology, known as the science of minute, is changing the approach to cancer and especially future diagnosis and treatment. Nanotechnology permits scientists to fabricate new apparatuses that are definitely smaller than cells, giving them the chance to attack tumor diseased cells. This innovation not just empowers practitioners to recognize malignancies prior but additionally holds the guarantee of halting cancer growth before it further develops. This progressive approach is so exact, specialists will in future be able to outline a unique treatment for an individual’s own restorative and hereditary profile. Researchers are designing nanoparticles that detect and destroy diseased cells and this optimistic innovation could be personalized for targeted drug delivery, enhanced imaging and ongoing affirmation of cancer cell death. The National Cancer Institute remains hopeful that facilitated development, nanotechnology will drastically change cancer treatment.

Most cancer cells predominantly produce energy by glycolysis rather than oxidative phosphorylation via the tricarboxylic acid (TCA) cycle, even in the presence of an adequate oxygen supply (Warburg effect). However, little has been reported regarding the direct measurements of global metabolites in clinical tumor tissues. Here, we applied capillary electrophoresis time-of-flight mass spectrometry, which enables comprehensive and quantitative analysis of charged metabolites, to simultaneously measure their levels in tumor and grossly normal tissues obtained from 16 colon and 12 stomach cancer patients. Quantification of 94 metabolites in colon and 95 metabolites in stomach involved in glycolysis, the pentose phosphate pathway, the TCA and urea cycles, and amino acid and nucleotide metabolisms resulted in the identification of several cancer-specific metabolic traits. Extremely low glucose and high lactate and glycolytic intermediate concentrations were found in both colon and stomach tumor tissues, which indicated enhanced glycolysis and thus confirmed the Warburg effect. Significant accumulation of all amino acids except glutamine in the tumors implied autophagic degradation of proteins and active glutamine breakdown for energy production, i.e., glutaminolysis. In addition, significant organ-specific differences were found in the levels of TCA cycle intermediates, which reflected the dependency of each tissue on aerobic respiration according to oxygen availability. The results uncovered unexpectedly poor nutritional conditions in the actual tumor microenvironment and showed that capillary electrophoresis coupled to mass spectrometry-based metabolomics, which is capable of quantifying the levels of energy metabolites in tissues, could be a powerful tool for the development of novel anticancer agents that target cancer-specific metabolism.

In a stroke lesion, there is a core of necrotic cell death surrounded by a zone of tissue at risk, termed the penumbra. In the penumbra, there is usually less severe tissue damage. Programmed cell death (PCD) pathways have been documented to be present in the penumbra. While many studies have used the term apoptosis as equivalent to PCD, the absence of complete biochemical and morphological characteristics of apoptosis, coupled with the ineffectiveness of caspase inhibitors, indicates that there are other important cell death pathways activated during stroke. A few caspase-independent cell death pathways have been identified and there are likely more to be described. Stroke injury leads to the activation of a cell death program, dependent on poly(ADP-ribose) polymerase-1 (PARP1) activation1 and culminating in apoptosis inducing factor (AIF) mediated cell death.2 Poly(ADP-ribose) (PAR) polymer is the death signal in this pathway and Thanatos is the Greek personification of death and mortality, hence, the name parthanatos. In this form of cell death that occurs in many different organ systems during ischemia-reperfusion injury, PAR polymer translocates from the nucleus to the cytoplasm and mitochondria. This leads to release of AIF from the mitochondria, an effect that is inhibited by poly(ADP-ribose) glycohydrolase (PARG), an enzyme that degrades PAR polymer.3 After cerebral focal ischemia reperfusion injury, mice with reduced PARG levels had higher infarct volumes than controls. On the other hand, mice overexpressing PARG had significantly lower infarct volumes. Combined, the current data indicate that PAR is a powerful death signal. What is not yet understood are the mechanisms of PAR translocation out of the nucleus and PAR-mediated AIF release from the mitochondria. Parthanatos is caspase-independent and is biochemically and morphologically distinct from apoptosis.4 Regulation of PAR signaling may be a useful therapeutic intervention to reduce stroke-mediated damage. Additional …

Proteomic Analysis Uncovers Measles Virus Protein C Interaction With p65–iASPP Protein Complex