Iron and thiol redox signaling in cancer: An exquisite balance to escape ferroptosis

Hemin enhances the 5-aminolevulinic acid-photodynamic therapy effect through the changes of cellular iron homeostasis

BACKGROUND

Photodynamic therapy (PDT) has been utilized as a promising alternative cancer treatment due to its minimum invasiveness over the years. Exogenous 5-aminolevulinic acid (ALA) triggers protoporphyrin IX (PpIX) accumulation, which happens in cancer cells. However, certain types of cancer exhibit reduced effectiveness in the PpIX accumulation mechanism. This study aimed to determine the effect of ALA-PDT combination with hemin on gastric carcinoma TMK-1 cells.

METHODS

This study utilized TMK-1 gastric cancer cell line to evaluate PpIX, ROS, and Fe2+ accumulation following the administration of ALA, hemin, and a combination of ALA and hemin PDT. We also evaluate the mRNA expressions related to iron homeostasis and treatment impacts on cell viability.

RESULTS

The co-addition of ALA and hemin PDT for 4 h of treatment resulted in a significant decrease in cell viability by up to 18 %. While ALA-PDT enhanced PpIX metabolism, the addition of hemin influenced both the production of reactive oxygen species (ROS) and cellular iron homeostasis by inducing Fe2+ accumulation and affecting mRNA levels of IRP, Tfr1, Ferritin, NFS1, and SDHB.

CONCLUSION

These findings suggest that the addition of ALA and hemin enhances phototoxicity in TMK-1 cells. The combination of ALA and hemin with PDT induces cell death, evidenced by increased cytotoxicity properties such as PpIX and ROS, along with significant changes in TMK-1 gastric cancer iron homeostasis. Therefore, the combination of ALA and hemin could be one of the alternatives in photodynamic therapy for cancer in the future.

Ferroptosis: Latest evidence and perspectives on plant-derived natural active compounds mitigating doxorubicin-induced cardiotoxicity

Doxorubicin (DOX) is a chemotherapy drug widely used in clinical settings, acting as a first-line treatment for various malignant tumors. However, its use is greatly limited by the cardiotoxicity it induces, including doxorubicin-induced cardiomyopathy (DIC). The mechanisms behind DIC are not fully understood, but its potential biological mechanisms are thought to include oxidative stress, inflammation, energy metabolism disorders, mitochondrial damage, autophagy, apoptosis, and ferroptosis. Recent studies have shown that cardiac injury induced by DOX is closely related to ferroptosis. Due to their high efficacy, availability, and low side effects, natural medicine treatments hold strong clinical potential. Currently, natural medicines have been shown to mitigate DOX-induced ferroptosis and ease DIC through various functions such as antioxidation, iron ion homeostasis correction, lipid metabolism regulation, and mitochondrial function improvement. Therefore, this review summarizes the mechanisms of ferroptosis in DIC and the regulation by natural plant products, with the expectation of providing a reference for future research and development of inhibitors targeting ferroptosis in DIC. This review explores the mechanisms of ferroptosis in doxorubicin-induced cardiomyopathy (DIC) and summarizes how natural plant products can alleviate DIC by inhibiting ferroptosis through reducing oxidative stress, correcting iron ion homeostasis, regulating lipid metabolism, and improving mitochondrial function.

The regulation and function of Nrf2 signaling in ferroptosis-activated cancer therapy

Ferroptosis is an iron-dependent programmed cell death process that involves lipid oxidation via the Fenton reaction to produce lipid peroxides, causing disruption of the lipid bilayer, which is essential for cellular survival. Ferroptosis has been implicated in the occurrence and treatment response of various types of cancer, and targeting ferroptosis has emerged as a promising strategy for cancer therapy. However, cancer cells can escape cellular ferroptosis by activating or remodeling various signaling pathways, including oxidative stress pathways, thereby limiting the efficacy of ferroptosis-activating targeted therapy. The key anti-oxidative transcription factor, nuclear factor E2 related factor 2 (Nrf2 or NFE2L2), plays a dominant role in defense machinery by reprogramming the iron, intermediate, and glutathione peroxidase 4 (GPX4)-related network and the antioxidant system to attenuate ferroptosis. In this review, we summarize the recent advances in the regulation and function of Nrf2 signaling in ferroptosis-activated cancer therapy and explore the prospect of combining Nrf2 inhibitors and ferroptosis inducers as a promising cancer treatment strategy.

Inhibition of Slc39a14/Slc39a8 reduce vascular calcification via alleviating iron overload induced ferroptosis in vascular smooth muscle cells

BACKGROUND

Vascular calcification (VC) is an independent risk factor for cardiovascular diseases. Recently, ferroptosis has been recognised as a novel therapeutic target for cardiovascular diseases. Although an association between ferroptosis and vascular calcification has been reported, the role and mechanism of iron overload in vascular calcification are still poorly understood. Specifically, further in-depth research is required on whether metalloproteins SLC39a14 and SLC39a8 are involved in ferroptosis induced by iron overload.

METHODS

R language was employed for the differential analysis of the dataset, revealing the correlation between ferroptosis and calcification. The experimental approaches encompassed both in vitro and in vivo studies, incorporating the use of iron chelators and models of iron overload. Additionally, gain- and loss-of-function experiments were conducted to investigate iron's effects on vascular calcification comprehensively. Electron microscopy, immunofluorescence, western blotting, and real-time polymerase chain reaction were used to elucidate how Slc39a14 and Slc39a8 mediate iron overload and promote calcification.

RESULTS

Ferroptosis was observed in conjunction with vascular calcification (VC); the association was consistently confirmed by in vitro and in vivo studies. Our results showed a positive correlation between iron overload in VSMCs and calcification. Iron chelators are effective in reversing VC and iron overload exacerbates this process. The expression levels of the metal transport proteins Slc39a14 and Slc39a8 were significantly upregulated during calcification; the inhibition of their expression alleviated VC. Conversely, Slc39a14 overexpression exacerbates calcification and promotes intracellular iron accumulation in VSMCs.

CONCLUSIONS

Our research demonstrates that iron overload occurs during VC, and that inhibition of Slc39a14 and Slc39a8 significantly relieves VC by intercepting iron overload-induced ferroptosis in VSMCs, providing new insights into the VC treatment.

Polycytosine RNA-binding protein 1 regulates osteoblast function via a ferroptosis pathway in type 2 diabetic osteoporosis

BACKGROUND

Recently, type 2 diabetic osteoporosis (T2DOP) has become a research hotspot for the complications of diabetes, but the specific mechanism of its occurrence and development remains unknown. Ferroptosis caused by iron overload is con-sidered an important cause of T2DOP. Polycytosine RNA-binding protein 1 (PCBP1), an iron ion chaperone, is considered a protector of ferroptosis.

AIM

To investigate the existence of ferroptosis and specific role of PCBP1 in the development of type 2 diabetes.

METHODS

A cell counting kit-8 assay was used to detect changes in osteoblast viability under high glucose (HG) and/or ferroptosis inhibitors at different concentrations and times. Transmission electron microscopy was used to examine the morphological changes in the mitochondria of osteoblasts under HG, and western blotting was used to detect the expression levels of PCBP1, ferritin, and the ferroptosis-related protein glutathione peroxidase 4 (GPX4). A lentivirus silenced and overexpressed PCBP1. Western blotting was used to detect the expression levels of the osteoblast functional proteins osteoprotegerin (OPG) and osteocalcin (OCN), whereas flow cytometry was used to detect changes in reactive oxygen species (ROS) levels in each group.

RESULTS

Under HG, the viability of osteoblasts was considerably decreased, the number of mitochondria undergoing atrophy was considerably increased, PCBP1 and ferritin expression levels were increased, and GPX4 expression was decreased. Western blotting results demonstrated that infection with lentivirus overexpressing PCBP1, increased the expression levels of ferritin, GPX4, OPG, and OCN, compared with the HG group. Flow cytometry results showed a reduction in ROS, and an opposite result was obtained after silencing PCBP1.

CONCLUSION

PCBP1 may protect osteoblasts and reduce the harm caused by ferroptosis by promoting ferritin expression under a HG environment. Moreover, PCBP1 may be a potential therapeutic target for T2DOP.

Research progress of ferroptosis and inflammatory bowel disease

Inflammatory bowel disease (IBD) is a non-specific chronic inflammatory disorder of the gastrointestinal tract, imposing significant burdens on both society and individuals. As a new type of regulated cell death (RCD), ferroptosis is different from classic RCDs such as apoptosis and necrosis in cell morphology, biochemistry and genetics. The main molecular mechanisms of ferroptosis include dysregulation of iron metabolism, impaired antioxidant capacity, mitochondrial dysfunction, accumulation of lipid-associated super-oxides, and membrane disruption. In recent years, increasing evidence has shown that ferroptosis is involved in the pathophysiology of inflammatory bowel disease. However, the exact roles and underlying molecular mechanisms have not been fully elucidated. This article reviews the mechanism of ferroptosis in the occurrence and development of inflammatory bowel disease, in order to provide new ideas for the pathophysiological research of inflammatory bowel disease. Additionally, we discuss potential strategies for the prevention and treatment of inflammatory bowel disease by targeting ferroptosis.

Dihydroartemisinin eliminates senescent cells by promoting autophagy-dependent ferroptosis via AMPK/mTOR signaling pathway

Cellular senescence is an irreversible cell-cycle arrest in response to a variety of cellular stresses, which contribute to the pathogenesis of a variety of age-related degenerative diseases. However, effective antisenescence strategies are still lacking. Drugs that selectively target senescent cells represent an intriguing therapeutic strategy to delay aging and age-related diseases. Thus, we thought to investigate the effects of dihydroartemisinin (DHA) on senescent cells and elucidated its mechanisms underlying aging. Stress-induced premature senescence (SIPS) model was built in NIH3T3 cells using H2O2 and evaluated by β-galactosidase staining. Cells were exposed to DHA and subjected to cellular activity assays including viability, ferroptosis, and autophagy. The number of microtubule-associated protein light-chain 3 puncta was detected by immunofluorescence staining. The iron content was assessed by spectrophotometer and intracellular reactive oxygen species (ROS) was measured by fluorescent probe dichlorodihydrofluorescein diacetate. We found that DHA triggered senescent cell death via ferroptosis. DHA accelerated ferritin degradation via promoting autophagy, increasing the iron contents, promoting ROS accumulation, thus leading to ferroptotic cell death in SIPS cells. In addition, autophagy inhibitor BafA1 preconditioning inhibited ferroptosis induced by DHA. Moreover, Atg5 silencing and autophagy inhibitor BafA1 preconditioning inhibited ferroptosis induced by DHA. We also revealed that the expression of p-AMP-activated protein kinase (AMPK) and p-mammalian target of rapamycin (mTOR) in senescent cells was downregulated. These results suggested that DHA may be a promising drug candidate for clearing senescent cells by inducing autophagy-dependent ferroptosis via AMPK/mTOR signaling pathway.

TCM targets ferroptosis: potential treatments for cancer

Ferroptosis is caused by the accumulation of cellular reactive oxygen species that exceed the antioxidant load that glutathione (GSH) and phospholipid hydroperoxidases with GSH-based substrates can carry When the antioxidant capacity of cells is reduced, lipid reactive oxygen species accumulate, which can cause oxidative death. Ferroptosis, an iron-dependent regulatory necrosis pathway, has emerged as a new modality of cell death that is strongly associated with cancer. Surgery, chemotherapy and radiotherapy are the main methods of cancer treatment. However, resistance to these mainstream anticancer drugs and strong toxic side effects have forced the development of alternative treatments with high efficiency and low toxicity. In recent years, an increasing number of studies have shown that traditional Chinese medicines (TCMs), especially herbs or herbal extracts, can inhibit tumor cell growth and metastasis by inducing ferroptosis, suggesting that they could be promising agents for cancer treatment. This article reviews the current research progress on the antitumor effects of TCMs through the induction of ferroptosis. The aim of these studies was to elucidate the potential mechanisms of targeting ferroptosis in cancer, and the findings could lead to new directions and reference values for developing better cancer treatment strategies.

Targeting ferroptosis for leukemia therapy: exploring novel strategies from its mechanisms and role in leukemia based on nanotechnology

The latest findings in iron metabolism and the newly uncovered process of ferroptosis have paved the way for new potential strategies in anti-leukemia treatments. In the current project, we reviewed and summarized the current role of nanomedicine in the treatment and diagnosis of leukemia through a comparison made between traditional approaches applied in the treatment and diagnosis of leukemia via the existing investigations about the ferroptosis molecular mechanisms involved in various anti-tumor treatments. The application of nanotechnology and other novel technologies may provide a new direction in ferroptosis-driven leukemia therapies. The article explores the potential of targeting ferroptosis, a new form of regulated cell death, as a new therapeutic strategy for leukemia. It discusses the mechanisms of ferroptosis and its role in leukemia and how nanotechnology can enhance the delivery and efficacy of ferroptosis-inducing agents. The article not only highlights the promise of ferroptosis-targeted therapies and nanotechnology in revolutionizing leukemia treatment, but also calls for further research to overcome challenges and fully realize the clinical potential of this innovative approach. Finally, it discusses the challenges and opportunities in clinical applications of ferroptosis.

Mitochondria-mediated Ferroptosis in Diseases Therapy: From Molecular Mechanisms to Implications

Ferroptosis, a type of cell death involving iron and lipid peroxidation, has been found to be closely associated with the development of many diseases. Mitochondria are vital components of eukaryotic cells, serving important functions in energy production, cellular metabolism, and apoptosis regulation. Presently, the precise relationship between mitochondria and ferroptosis remains unclear. In this study, we aim to systematically elucidate the mechanisms via which mitochondria regulate ferroptosis from multiple perspectives to provide novel insights into mitochondrial functions in ferroptosis. Additionally, we present a comprehensive overview of how mitochondria contribute to ferroptosis in different conditions, including cancer, cardiovascular disease, inflammatory disease, mitochondrial DNA depletion syndrome, and novel coronavirus pneumonia. Gaining a comprehensive understanding of the involvement of mitochondria in ferroptosis could lead to more effective approaches for both basic cell biology studies and medical treatments.

Oxytosis/Ferroptosis in Neurodegeneration: the Underlying Role of Master Regulator Glutathione Peroxidase 4 (GPX4)

Oxytosis/ferroptosis is an iron-dependent oxidative form of cell death triggered by lethal accumulation of phospholipid hydroperoxides (PLOOHs) in membranes. Failure of the intricate PLOOH repair system is a principle cause of ferroptotic cell death. Glutathione peroxidase 4 (GPX4) is distinctly vital for converting PLOOHs in membranes to non-toxic alcohols. As such, GPX4 is known as the master regulator of oxytosis/ferroptosis. Ferroptosis has been implicated in a number of disorders such as neurodegenerative diseases (amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD), etc.), ischemia/reperfusion injury, and kidney degeneration. Reduced function of GPX4 is frequently observed in degenerative disorders. In this study, we examine how diminished GPX4 function may be a critical event in triggering oxytosis/ferroptosis to perpetuate or initiate the neurodegenerative diseases and assess the possible therapeutic importance of oxytosis/ferroptosis in neurodegenerative disorders. These discoveries are important for advancing our understanding of neurodegenerative diseases because oxytosis/ferroptosis may provide a new target to slow the course of the disease.

Elaborate cooperation of poly(rC)-binding proteins 1/2 and glutathione in ferroptosis induced by plasma-activated Ringer's lactate

Reactive species are involved in various aspects of neoplastic diseases, including carcinogenesis, cancer-specific metabolism and therapeutics. Non-thermal plasma (NTP) can directly provide reactive species, by integrating atmospheric and interjacent molecules as substrates, to represent a handy strategy to load oxidative stress in situ. NTP causes apoptosis and/or ferroptosis specifically in cancer cells of various types. Plasma-activated Ringer's lactate (PAL) is another modality at the preclinical stage as cancer therapeutics, based on more stable reactive species. PAL specifically kills malignant mesothelioma (MM) cells, employing lysosomal ·NO as a switch from autophagy to ferroptosis. However, the entire molecular mechanisms have not been elucidated yet. Here we studied cytosolic iron regulations in MM and other cancer cells in response to PAL exposure. We discovered that cells with higher catalytic Fe(II) are more susceptible to PAL-induced ferroptosis. PAL caused a cytosolic catalytic Fe(II)-associated pathology through iron chaperones, poly (rC)-binding proteins (PCBP)1/2, inducing a disturbance in glutathione-regulated iron homeostasis. PCBP1/NCOA4-mediated ferritinophagy started at a later phase, further increasing cytosolic catalytic Fe(II), ending in ferroptosis. In contrast, PCBP2 after PAL exposure contributed to iron loading to mitochondria, leading to mitochondrial dysfunction. Therapeutic effect of PAL was successfully applied to an orthotopic MM xenograft model in mice. In conclusion, PAL can selectively sensitize MM cells to ferroptosis by remodeling cytoplasmic iron homeostasis, where glutathione and PCBPs play distinct roles, resulting in lethal ferritinophagy and mitochondrial dysfunction. Our findings indicate the clinical application of PAL as a ferroptosis-inducer and the potential of PCBPs as novel targets in cancer therapeutics.

Differential metabolites screening in yak (Bos grunniens) seminal plasma after cryopreservation and the evaluation of the effect of galactose on post-thaw sperm motility

Sperm survival and activity depend on the provision of energy and nutrients from seminal plasma (SP). This study aimed to investigate the variations of metabolites within SP before and after freezing and subsequently explore the potential regulatory mechanisms affecting yak sperm cryodamage due to changes in metabolites in the SP. Untargeted metabolomics analysis was performed to screen for differential metabolites, followed by KEGG analysis to identify enriched signaling pathways. The combinatorial analysis of metabolomics and sperm proteomics revealed the influence of key SP metabolites on sperm proteins. Subsequently, the relevant differentially expressed proteins were verified by Western blot analysis. Finally, the mechanism underlying the positive effect of galactose on sperm motility was determined by assessing the change in ATP content in sperm before and after freezing and thawing. The data showed that a total of 425 and 269 metabolites were identified in the positive and negative ion modes, respectively. Freezing and thawing resulted in the up-regulation of 70 metabolites and the down-regulation of 29 metabolites in SP. The primary impact of freezing and thawing was observed in carbohydrate metabolism, including pyruvate metabolism, pentose phosphate pathway, galactose metabolism, the TCA cycle, and butanoate metabolism. In the combined analysis and Western blot results, a significant positive correlation was observed between galactose and Aldo-keto reductase family 1 member B1 (AKR1B1) (P < 0.05), which has the ability to convert galactose into galactol. Furthermore, the addition of galactose to thawed semen improved sperm motility by increasing AKR1B1 protein in sperm and was associated with the content of ATP. These data identify differential metabolites between fresh and frozen-thawed SP and suggest that galactose is a valuable additive for cryopreserved sperm, providing a theoretical basis for further exploration of the refrigerant formula for yak sperm cryopreservation.

Charting the course of ferroptosis research in lung cancer: Insights from a bibliometric analysis

Background

Lung cancer, a major cause of cancer-related mortality globally, necessitates innovative therapeutic strategies. Ferroptosis, an iron-dependent, non-apoptotic cell death form, has risen as a crucial therapeutic target. This study aims to conduct a comprehensive bibliometric analysis of ferroptosis in lung cancer, highlighting principal research trends, influential publications, and prospective future directions.

Methods

This study utilized bibliometric tools such as VOSviewer, CiteSpace, and the R package "bibliometrix" to thoroughly analyze 488 articles on ferroptosis in lung cancer from 2014 to October 2023. Data from the Web of Science Core Collection were analyzed to determine spatial and temporal trends, identify prominent authors and seminal works, and uncover emerging hotspots and frontiers of the field. The literature was segmented into coherent thematic groups through cluster analysis.

Results

Our analysis revealed a significant exponential growth in publications from 2019 to 2023, mirroring the increasing interest in this area. Predominantly, the influential research was published in high-impact journals, with Scott J. Dixon's works being the most cited. The study identified four primary research themes: Lung Cancer Specifics; Biomarker Identification and Prognosis; Cellular Death Mechanisms and Metabolic Regulation; and Cancer Stem Cells and Therapeutic Resistance. Recent studies have increasingly focused on areas such as the immune microenvironment and mitochondrial dysfunction. Furthermore, the analysis highlighted the field's global collaborative nature, with significant contributions from China, the USA, and Germany.

Conclusion

This extensive bibliometric analysis emphasizes the growing importance of ferroptosis in lung cancer research. The identified themes and emerging topics underline the field's complexity and suggest new research avenues. This study promotes a holistic research approach, advocating for the exploration of innovative ferroptosis-targeting therapies that could revolutionize lung cancer treatment.

SARS-CoV-2 Accessory Protein Orf7b Induces Lung Injury via c-Myc Mediated Apoptosis and Ferroptosis

The pandemic of coronavirus disease 2019 (COVID-19) has been the foremost modern global public health challenge. The airway is the primary target in severe acute respiratory distress syndrome coronavirus 2 (SARS-CoV-2) infection, with substantial cell death and lung injury being signature hallmarks of exposure. The viral factors that contribute to cell death and lung injury remain incompletely understood. Thus, this study investigated the role of open reading frame 7b (Orf7b), an accessory protein of the virus, in causing lung injury. In screening viral proteins, we identified Orf7b as one of the major viral factors that mediates lung epithelial cell death. Overexpression of Orf7b leads to apoptosis and ferroptosis in lung epithelial cells, and inhibitors of apoptosis and ferroptosis ablate Orf7b-induced cell death. Orf7b upregulates the transcription regulator, c-Myc, which is integral in the activation of lung cell death pathways. Depletion of c-Myc alleviates both apoptotic and ferroptotic cell deaths and lung injury in mouse models. Our study suggests a major role of Orf7b in the cell death and lung injury attributable to COVID-19 exposure, supporting it as a potential therapeutic target.

Ferroptosis and its modulators: A raising target for cancer and Alzheimer's disease

The process of ferroptosis, a recently identified form of regulated cell death (RCD) is associated with the overloading of iron species and lipid-derived ROS accumulation. Ferroptosis is induced by various mechanisms such as inhibiting system Xc, glutathione depletion, targeting excess iron, and directly inhibiting GPX4 enzyme. Also, ferroptosis inhibition is achieved by blocking excessive lipid peroxidation by targeting different pathways. These mechanisms are often related to the pathophysiology and pathogenesis of diseases like cancer and Alzheimer's. Fundamentally distinct from other forms of cell death, such as necrosis and apoptosis, ferroptosis differs in terms of biochemistry, functions, and morphology. The mechanism by which ferroptosis acts as a regulatory factor in many diseases remains elusive. Studying the activation and inhibition of ferroptosis as a means to mitigate the progression of various diseases is a highly intriguing and actively researched topic. It has emerged as a focal point in etiological research and treatment strategies. This review systematically summarizes the different mechanisms involved in the inhibition and induction of ferroptosis. We have extensively explored different agents that can induce or inhibit ferroptosis. This review offers current perspectives on recent developments in ferroptosis research, highlighting the disease's etiology and presenting references to enhance its understanding. It also explores new targets for the treatment of cancer and Alzheimer's disease.

Mitochondria-related signaling pathways involved in breast cancer regulate ferroptosis

Ferroptosis is a novel form of regulated cell death characterized by iron-dependent excessive lipid peroxidation. The core organelle involved in ferroptosis is mitochondria. Mitochondria undergoing ferroptosis are distinct from normal mitochondria in terms of morphology, biochemistry, gene expression, and energy metabolism. An increasing number of studies have shown that mitochondria and their associated metabolic pathways mediate ferroptosis in the development and progression of breast cancer. In this review, we discuss the relevant research about ferroptosis in breast cancer and provide a comprehensive summary of mitochondrial regulation in ferroptosis from the perspective of lipid metabolism, oxidative phosphorylation, ion metabolism, glycometabolism, and nucleotide metabolism. We also summarize the application of mitochondrial metabolism-related pathways as ferroptosis treatment targets. Here we provide new insights into the relationship between mitochondria, ferroptosis, and breast cancer treatment.

Ferroptosis and aerobic training in ageing

 Ferroptosis is a form of programmed cell death that plays a significant role in causing several diseases such as heart attack and heart failure, through alterations in fat, amino acid, and iron metabolism. Comprehending the regulatory mechanisms of ferroptosis signaling is critical because it has a considerable effect on the elderly's mortality. Conversely, age-related changes in substrate metabolism and metabolite levels are recognized to give rise to obesity. Furthermore, research has proposed that aging and obesity-related changes in substrate metabolism may aggravate ferroptosis. The suppression of ferroptosis holds potential as a successful therapeutic approach for managing different diseases, including sarcopenia, cardiovascular diseases, and central nervous system diseases. However, the pathologic and biological mechanisms behind the function of ferroptosis are not fully comprehended yet. Physical activity could affect lipid, amino acid, and iron metabolism to modulate ferroptosis. The aim of this study is to showcase the current understanding of the molecular mechanisms leading to ferroptosis and discuss the role of aging and physical activity in this phenomenon.

In Situ Activatable Nitrobenzene-Cysteine-Copper(II) Nano-complexes for Programmed Photodynamic Cancer Therapy

Photodynamic therapy (PDT) has been used to reduce cancerous and precancerous cells via reactive oxygen species (ROS) generation from photosensitizers. Numerous photosensitizers are available today to treat a variety of diseases, but their therapeutic efficacy is hindered within the tumor microenvironment, and there are safety concerns associated with their non-specific activation. In this work, we disclosed a nano-therapeutic based on in situ activatable nitrobenzene-cysteine-copper(II) nano-complexes (NCCNs) that work within cancer cells. Among the NCCNs, CyP shows outstanding potential as a promising candidate for programmed photodynamic cancer therapy with its unique properties such as (i) bright near-infrared imaging, (ii) chemodynamic therapeutic effect, (iii) photodynamic therapeutic effect (types I and II), and (iv) anti-cancer effect by anti-angiogenesis in early cancer stage under light. Overall, this work opens up exciting possibilities for the development of innovative and effective treatments for cancer, paving the way for future advancements in the clinical medicine field.

Ferroptosis and tumor immunity: In perspective of the major cell components in the tumor microenvironment

Ferroptosis is an iron-dependent form of cell death driven by lipid peroxidation, which is morphologically, biochemically, and genetically distinct from apoptosis, necrosis, and autophagy. Mounting studies on the essential role of ferroptosis have been published in the progression of solid tumors, metastasis, therapy, and therapy resistance. Studies showed that ferroptosis is a "double-edged sword" in tumor immunity, which means it may have both tumor-antagonizing and tumor-promoting functions. The tumor microenvironment (TME) comprises not only tumor cells but also surrounding immune cells, stromal cells, as well as noncellular components such as the extracellular matrix (ECM), cytokines, growth factors, and extracellular vesicles (EVs). In the complex and diverse condition in TME where tumor cells grow, changes in each constituent may impact tumor destiny differently. Recently, several studies have revealed the interaction between ferroptosis and different constituents in TME. Both tumor cells and nontumor cells have a dual role in tumor immunity and influence tumor progression through ferroptosis. Herein, this review aims at summarizing the role of ferroptosis in tumor immunity based on TME, focusing on the mechanisms of the interaction between the ferroptosis and the different constituents in TME, illuminating how ferroptosis plays its role in promoting or antagonizing tumors by acting with varying components in TME and proposing several questions in immunomodulatory effects of ferroptosis and ferroptosis-associated immunotherapy.

Mechanisms and applications of ferroptosis-associated regulators in cancer therapy and drug resistance

Iron is an essential element for almost all living things. Both iron excess and iron deficiency can damage the body's health, but the body has developed complex mechanisms to regulate iron balance. The imbalance of iron homeostasis and lipid peroxidation are important features of ferroptosis. In this review, we summarize the latest regulatory mechanisms of ferroptosis, the roles of relevant regulators that target ferroptosis for cancer therapy, and their relationship to drug resistance. In conclusion, targeting ferroptosis is an important strategy for cancer therapy.

The influence of microbiota on ferroptosis in intestinal diseases

Ferroptosis is a distinctive form of iron-dependent necrotic cell death, characterized by excessive lipid peroxidation on cellular membranes and compromised cellular antioxidant defenses. Multiple metabolic pathways, including iron and lipid metabolism, as well as antioxidant systems, contribute to the execution of ferroptosis. The gut microbiota exerts regulatory effects on ferroptosis through its microbial composition, biological functions, and metabolites. Notably, most pathogenic bacteria tend to promote ferroptosis, thereby inducing or exacerbating diseases, while most probiotics have been shown to protect against cell death. Given microbiota colonization in the gut, an intimate association is found between intestinal diseases and microbiota. This review consolidates the essential aspects of ferroptotic processes, emphasizing key molecules and delineating the intricate interplay between gut microbiota and ferroptosis. Moreover, this review underscores the potential utility of gut microbiota modulation in regulating ferroptosis for the treatment of intestinal diseases.

Managing ferroptosis-related diseases with indirect dietary modulators of ferroptosis

Ferroptosis is an iron-dependent form of programmed cell death driven by excessive oxidation of polyunsaturated phospholipids on cellular membranes. Accumulating evidence suggests that ferroptosis has been implicated in the pathological process of various diseases, such as cardiovascular diseases, neurological diseases, liver diseases, kidney injury, lung injury, diabetes, and cancer. Targeting ferroptosis is therefore considered to be a reasonable strategy to fight against ferroptosis-associated diseases. Many dietary bioactive agents have been identified to be able to either suppress or promote ferroptosis, indicating that ferroptosis-based intervention by dietary approach may be an effective strategy for preventing and treating diseases associated with ferroptosis dysregulation. In this review, we summarize the present understanding of the functional role of ferroptosis in the pathogenesis of aforementioned diseases with an emphasis on the evidence of managing ferroptosis-related diseases with indirect dietary modulators of ferroptosis and propose issues that need to be addressed to promote practical application of dietary approach targeting ferroptosis.

Moxibustion ameliorates cerebral ischemia-reperfusion injury by regulating ferroptosis in rats

Moxibustion is an effective treatment for the clinical management of acute cerebral infarction. However, its exact mechanism of action is still not fully understood. This study aimed to investigate the protective effect of moxibustion on cerebral ischemia-reperfusion injury (CIRI) in rats. Middle cerebral artery occlusion/reperfusion (MCAO/R) was used to construct a CIRI rat model, all animals were randomly divided into four groups including sham operation group, MCAO/R group (MCAO/R), moxibustion therapy + MCAO/R (Moxi) and ferrostatin-1 + MCAO/R (Fer-1) group. In the Moxi group, moxibustion treatment was initiated 24 h after modeling, once a day for 30 mins each time for 7 days. Moreover, the Fer-1 group received intraperitoneal injections of Fer-1 12 h after modeling, once a day for a total of 7 days. The results showed that moxibustion could reduce nerve function damage and neuronal death. Additionally, moxibustion could reduce the production of lipid peroxides such as lipid peroxide, malondialchehyche and ACSL4 to regulate lipid metabolism, promote the production of glutathione and glutathione peroxidase 4 and reduce the expression of hepcidin by inhibiting the production of inflammatory factor interleukin-6, therefore, downregulating the expression of SLC40A1, reducing the iron level in the cerebral cortex, reducing the accumulation of reactive oxygen species and inhibiting ferroptosis. Based on our studies, it can be concluded that moxibustion has the ability to inhibit ferroptosis of nerve cells post CIRI and plays a protective role in the brain. This protective role can be attributed to the regulation of iron metabolism of nerve cells, reduction of iron deposition in the hippocampus and lowering the level of lipid peroxidation.

Three-Dimensional Regulation of Ferroptosis at the Intersection of Iron, Sulfur, and Oxygen Executing Scrap and Build Toward Evolution

Significance: Iron is an essential element for every life on earth as a primary media for electron flow. Sulfur compounds as sulfhydryls counteract catalytic activity of iron whereas sulfur overdose is also toxic. In aerobic organisms, oxygen is the major media for electron transfer with higher intracellular mobility, which cooperates with the iron system. Based on the importance of iron, there is no active pathway to excrete iron outside the body in higher species. Whereas bacterial infection causes a scramble for iron in situ, cancer can be the outcome of the side effects of long use of iron and oxygen. Recent Advances: Ferroptosis is a recently coined cell death, defined as catalytic Fe(II)-dependent regulated necrosis accompanied by lipid peroxidation. Researchers recently recognized that ferroptosis is involved in a variety of physiological and pathological contexts, including embryonic erythropoiesis, aging, neurodegeneration and cancer cell death. Alternatively, carcinogenesis is a process to obtain iron addiction with ferroptosis-resistance, based on rodent animal studies. Critical Issues: Here we propose that ferroptosis is three-dimensionally regulated by iron, sulfur and oxygen, which correspond to oxidants, antioxidants and membrane fluidity with susceptibility to lipid peroxidation, respectively. Future Directions: Whereas life attempts to prevent ferroptosis, ferroptotic cells eventually emit iron-loaded ferritin as extracellular vesicles to maintain monopoly of iron. Antioxid. Redox Signal. 39, 807-815.

The Interplay between Mitochondrial Dysfunction and Ferroptosis during Ischemia-Associated Central Nervous System Diseases

Cerebral ischemia, a leading cause of disability and mortality worldwide, triggers a cascade of molecular and cellular pathologies linked to several central nervous system (CNS) disorders. These disorders primarily encompass ischemic stroke, Alzheimer's disease (AD), Parkinson's disease (PD), epilepsy, and other CNS conditions. Despite substantial progress in understanding and treating the underlying pathological processes in various neurological diseases, there is still a notable absence of effective therapeutic approaches aimed specifically at mitigating the damage caused by these illnesses. Remarkably, ischemia causes severe damage to cells in ischemia-associated CNS diseases. Cerebral ischemia initiates oxygen and glucose deprivation, which subsequently promotes mitochondrial dysfunction, including mitochondrial permeability transition pore (MPTP) opening, mitophagy dysfunction, and excessive mitochondrial fission, triggering various forms of cell death such as autophagy, apoptosis, as well as ferroptosis. Ferroptosis, a novel type of regulated cell death (RCD), is characterized by iron-dependent accumulation of lethal reactive oxygen species (ROS) and lipid peroxidation. Mitochondrial dysfunction and ferroptosis both play critical roles in the pathogenic progression of ischemia-associated CNS diseases. In recent years, growing evidence has indicated that mitochondrial dysfunction interplays with ferroptosis to aggravate cerebral ischemia injury. However, the potential connections between mitochondrial dysfunction and ferroptosis in cerebral ischemia have not yet been clarified. Thus, we analyzed the underlying mechanism between mitochondrial dysfunction and ferroptosis in ischemia-associated CNS diseases. We also discovered that GSH depletion and GPX4 inactivation cause lipoxygenase activation and calcium influx following cerebral ischemia injury, resulting in MPTP opening and mitochondrial dysfunction. Additionally, dysfunction in mitochondrial electron transport and an imbalanced fusion-to-fission ratio can lead to the accumulation of ROS and iron overload, which further contribute to the occurrence of ferroptosis. This creates a vicious cycle that continuously worsens cerebral ischemia injury. In this study, our focus is on exploring the interplay between mitochondrial dysfunction and ferroptosis, which may offer new insights into potential therapeutic approaches for the treatment of ischemia-associated CNS diseases.

Iron links endogenous and exogenous nanoparticles

Current progress in biology and medical science is based on the observation at the level of nanometers via electron microscopy and computation. Of note, the size of most cells in higher species exists in a limited range from 5 to 50 μm. Recently, it was demonstrated that endogenous extracellular nanoparticles play a role in communication among various cellular types in a variety of contexts. Among them, exosomes in serum have been established as biomarkers for human diseases by analyzing the cargo molecules. No life on the earth can survive without iron. However, excess iron can be a risk for carcinogenesis in rodents and humans. Nano-sized molecules may cause unexpected bioeffects, including carcinogenesis, which is a process to establish cellular iron addiction with ferroptosis-resistance. Asbestos and carbon nanotubes are the typical examples, leading to carcinogenesis by the alteration of iron metabolism. Recently, we found that CD63, one of the representative markers of exosomes, is under the regulation of iron-responsive element/iron-regulatory protein system. This is a safe strategy to share excess iron in the form of holo-ferritin between iron-sufficient and -deficient cells. On the other hand, damaged cells may secrete holo-ferritin-loaded exosomes as in the case of macrophages in ferroptosis after asbestos exposure. These holo-ferritin-loaded exosomes can cause mutagenic DNA damage in the recipient mesothelial cells. Thus, there is an iron link between exogenous and endogenous nanoparticles, which requires further investigation for better understanding and the future applications.

NeuroD4 converts glioblastoma cells into neuron-like cells through the SLC7A11-GSH-GPX4 antioxidant axis

Cell fate and proliferation ability can be transformed through reprogramming technology. Reprogramming glioblastoma cells into neuron-like cells holds great promise for glioblastoma treatment, as it induces their terminal differentiation. NeuroD4 (Neuronal Differentiation 4) is a crucial transcription factor in neuronal development and has the potential to convert astrocytes into functional neurons. In this study, we exclusively employed NeuroD4 to reprogram glioblastoma cells into neuron-like cells. In vivo, the reprogrammed glioblastoma cells demonstrated terminal differentiation, inhibited proliferation, and exited the cell cycle. Additionally, NeuroD4 virus-infected xenografts exhibited smaller sizes compared to the GFP group, and tumor-bearing mice in the GFP+NeuroD4 group experienced prolonged survival. Mechanistically, NeuroD4 overexpression significantly reduced the expression of SLC7A11 and Glutathione peroxidase 4 (GPX4). The ferroptosis inhibitor ferrostatin-1 effectively blocked the NeuroD4-mediated process of neuron reprogramming in glioblastoma. To summarize, our study demonstrates that NeuroD4 overexpression can reprogram glioblastoma cells into neuron-like cells through the SLC7A11-GSH-GPX4 signaling pathway, thus offering a potential novel therapeutic approach for glioblastoma.

A comprehensive overview of recent developments on the mechanisms and pathways of ferroptosis in cancer: the potential implications for therapeutic strategies in ovarian cancer

Cancer cells adapt to environmental changes and alter their metabolic pathways to promote survival and proliferation. Metabolic reprogramming not only allows tumor cells to maintain a reduction-oxidation balance by rewiring resources for survival, but also causes nutrient addiction or metabolic vulnerability. Ferroptosis is a form of regulated cell death characterized by the iron-dependent accumulation of lipid peroxides. Excess iron in ovarian cancer amplifies free oxidative radicals and drives the Fenton reaction, thereby inducing ferroptosis. However, ovarian cancer is characterized by ferroptosis resistance. Therefore, the induction of ferroptosis is an exciting new targeted therapy for ovarian cancer. In this review, potential metabolic pathways targeting ferroptosis were summarized to promote anticancer effects, and current knowledge and future perspectives on ferroptosis for ovarian cancer therapy were discussed. Two therapeutic strategies were highlighted in this review: directly inducing the ferroptosis pathway and targeting metabolic vulnerabilities that affect ferroptosis. The overexpression of SLC7A11, a cystine/glutamate antiporter SLC7A11 (also known as xCT), is involved in the suppression of ferroptosis. xCT inhibition by ferroptosis inducers (e.g., erastin) can promote cell death when carbon as an energy source of glucose, glutamine, or fatty acids is abundant. On the contrary, xCT regulation has been reported to be highly dependent on the metabolic vulnerability. Drugs that target intrinsic metabolic vulnerabilities (e.g., GLUT1 inhibitors, PDK4 inhibitors, or glutaminase inhibitors) predispose cancer cells to death, which is triggered by decreased nicotinamide adenine dinucleotide phosphate generation or increased reactive oxygen species accumulation. Therefore, therapeutic approaches that either directly inhibit the xCT pathway or target metabolic vulnerabilities may be effective in overcoming ferroptosis resistance. Real-time monitoring of changes in metabolic pathways may aid in selecting personalized treatment modalities. Despite the rapid development of ferroptosis-inducing agents, therapeutic strategies targeting metabolic vulnerability remain in their infancy. Thus, further studies must be conducted to comprehensively understand the precise mechanism linking metabolic rewiring with ferroptosis.

ROS induced lipid peroxidation and their role in ferroptosis

Reactive oxygen species (ROS) play a crucial part in the process of cell death, including apoptosis, autophagy, and ferroptosis. ROS involves in the oxidation of lipids and generate 4-hydroxynonenal and other compounds associated with it. Ferroptosis may be facilitated by lipid peroxidation of phospholipid bilayers. In order to offer novel ideas and directions for the investigation of disorders connected to these processes, we evaluate the function of ROS in lipid peroxidation which ultimately leads to ferroptosis as well as proposed crosstalk mechanisms between ferroptosis and other types programmed cell death.

Free Radical and Viral Infection: A Review from the Perspective of Ferroptosis

Free radicals, including reactive oxygen species (ROS) and reactive nitrogen species (RNS), play critical roles in various physiological activities such as cell differentiation, apoptosis, and vascular tension when existing in cells at low levels. However, excessive amounts of free radicals are harmful, causing DNA damage, lipid peroxidation, protein degeneration, and abnormal cell death. Certain viral infections induce cells to produce excessive free radicals, which in multiple ways help the virus to replicate, mature, and exit. Iron is a necessary element for many intracellular enzymes, involved in both cellular activities and viral replication. Ferroptosis, a programmed cell death mode distinct from apoptosis, necrosis, and pyroptosis, is characterized by lipid peroxide accumulation and damage to the antioxidant system, affecting many cellular processes. Viral infection commonly manifests as decreased glutathione (GSH) content and down-regulated glutathione peroxidase 4 (GPX4) activity, similar to ferroptosis. Recent studies have suggested a possible relationship among free radicals, viral infections and ferroptosis. This review aims to elucidate the molecular mechanism linking free radicals and ferroptosis during viral infections and provide a new theoretical basis for studying viral pathogenesis and control.

Isoorientin reverses lung cancer drug resistance by promoting ferroptosis via the SIRT6/Nrf2/GPX4 signaling pathway

Cisplatin, or DDP, is a highly successful and well-known chemotherapy drug used to treat cancer. Acquired resistance to chemotherapy is a major clinical concern, yet the mechanisms of this resistance are still unknown. Ferroptosis is a type of cell death distinct from other forms, fueled by a buildup of iron-associated lipid reactive oxygen species (ROS). Gaining insight into the process of ferroptosis could lead to novel treatments for overcoming cancer resistance. In this study, the combination of isoorientin (IO) and DDP treatment resulted in a significant decrease in the viability of drug-resistant cells, a substantial increase in intracellular iron, malondialdehyde (MDA) and ROS concentrations, a notable decrease in glutathione concentration, and the occurrence of ferroptosis in cells, as revealed by in vitro and in vivo experiments. Additionally, there was a decrease in the expression of nuclear factor-erythroid factor 2-related factor 2 (Nrf2), glutathione peroxidase 4 (GPX4), and sirtuin 6 (SIRT6) proteins, and an increase in cellular ferroptosis. Isoorientin acts as a mediator to regulate cellular ferroptosis and reverse drug resistance in lung cancer cells by controlling the SIRT6/Nrf2/GPX4 signaling pathway. The findings of this study suggest that IO can promote ferroptosis and reverse drug resistance in lung cancer through the SIRT6/Nrf2/GPX4 signaling pathway, thus offering a theoretical basis for its potential clinical application.

Comprehensive analysis of ferroptosis-related genes for clinical and biological significance in hepatocellular carcinoma

OBJECTIVE

This study aims to build a prognostic model of hepatocellular carcinoma (HCC) with ferroptosis-associated genes and explore their molecular function.

METHODS

Gene expression data and clinical information were obtained from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases and the International Cancer Genome Consortium (ICGC). A ferroptosis-associated gene set was obtained from the FerrDb database to identify differentially expressed genes. Then, we performed pathway enrichment analysis and immune infiltration analysis. A combined model based on ferroptosis-associated genes for predicting the overall survival of HCC was built by univariate and multivariate Cox regression analyses. Quantitative real-time polymerase chain reaction, Western blotting, colony formation, CCK-8, and EdU incorporation assays were performed to clarify the function of CAPG in the regulation of cell proliferation in human HCC. Ferroptosis was evaluated by glutathione (GSH), malondialdehyde (MDA), and total iron detection.

RESULTS

Forty-nine ferroptosis-related genes were significantly correlated with HCC, 19 of which had prognostic significance. CAPG, SLC7A11 and SQSTM1 were used to construct a novel risk model. The areas under the curves (AUCs) were 0.746 and 0.720 (1 year) in the training and validation groups, respectively. The survival analysis indicated that patients with high risk scores exhibited worse survival in the training and validation groups. The risk score was also identified as an independent prognostic factor of overall survival (OS), which established and validated the predictive abilities of the nomogram. The risk score was also significantly correlated with the expression of immune checkpoint genes. In vitro data showed that CAPG knockdown dramatically suppressed HCC cell proliferation, and the underlying molecular mechanisms might be that the silencing of CAPG reduced the expression of SLC7A11 and promoted ferroptosis.

CONCLUSION

The established risk model can be used to predict the prognosis of HCC. At the mechanistic level, CAPG may drive HCC progression by regulating SLC7A11, and ferroptosis activation in HCC patients with high CAPG expression may serve as a potential therapeutic strategy.

Defense systems to avoid ferroptosis caused by lipid peroxidation-mediated membrane damage

The presence of hydrogen peroxide along with ferrous iron produces hydroxyl radicals that preferably oxidize polyunsaturated fatty acids (PUFA) to alkyl radicals (L•). The reaction of L• with an oxygen molecule produces lipid peroxyl radical (LOO•) that collectively trigger chain reactions, which results in the accumulation of lipid peroxidation products (LOOH). Oxygenase enzymes, such as lipoxygenase, also stimulate the peroxidation of PUFA. The production of phospholipid hydroperoxides (P-LOOH) can result in the destruction of the architecture of cell membranes and ultimate cell death. This iron-dependent regulated cell death is generally referred to as ferroptosis. Radical scavengers, which include tocopherol and nitric oxide (•NO), react with lipid radicals and terminate the chain reaction. When tocopherol reductively detoxifies lipid radicals, the resultant tocopherol radicals are recycled via reduction by coenzyme Q or ascorbate. CoQ radicals are reduced back by the anti-ferroptotic enzyme FSP1. •NO reacts with lipid radicals and produces less reactive nitroso compounds. The resulting P-LOOH is reductively detoxified by the action of glutathione peroxidase 4 (GPX4) or peroxiredoxin 6 (PRDX6). The hydrolytic removal of LOOH from P-LOOH by calcium-independent phospholipase A2 leads the preservation of membrane structure. While the expression of such protective genes or the presence of these anti-oxidant compounds serve to maintain a healthy condition, tumor cells employ them to make themselves resistant to anti-tumor treatments. Thus, these defense mechanisms against ferroptosis are protective in ordinary cells but are also potential targets for cancer treatment.

Sodium hydrosulfide inhibits hemin-induced ferroptosis and lipid peroxidation in BV2 cells via the CBS/H2S system

Ferroptosis is a form of iron-dependent programmed cell death discovered in recent years that has been shown to be involved in diverse neurological disorders. Hydrogen sulfide (H₂S) is an important signaling molecule with neuroprotective effects, including antioxidation. However, whether the protective mechanism of H₂S is related to ferroptosis remains unknown. Therefore, in this study, we focused on the protective mechanisms of sodium hydrosulfide (NaHS, a donor of H₂S) against ferroptosis caused by intracerebral hemorrhage (ICH) using a hemin-induced BV2 cell injury model in vitro. Our results indicated that NaHS enhanced cell viability and reduced hemin-induced lactate dehydrogenase (LDH) release. NaHS suppressed ferroptosis after hemin treatment, which was confirmed by attenuated reactive oxygen species (ROS) and lipid peroxidation, maintained iron homeostasis, recovery of the expression of glutathione peroxidase 4 (GPX4) and solute carrier family 7-member 11 (SLC7A11), and increased glutathione (GSH) production. Moreover, we demonstrated that inhibiting ferroptosis improved cell survival and prevented hemin-induced oxidative stress. In addition, NaHS was also able to block ferroptosis inducer RSL3-induced ferroptotic cell death. We also found that NaHS increased cystathionine-β-synthase (CBS) expression and H₂S levels after hemin treatment. Furthermore, NaHS-induced ferroptosis reduction was inhibited by the CBS inhibitor aminooxyacetic acid (AOAA) as well as by CBS small interference RNA (siCBS). In summary, these findings demonstrated that NaHS protects against hemin-induced ferroptosis by reducing lipid peroxidation, inhibiting iron overload, increasing GSH production, and improving GPX4 and SLC7A11 via the CBS/H₂S system. The CBS/H₂S system may be a promising target for preventing ferroptosis after ICH.

Bioinorganic Modulators of Ferroptosis: A Review of Recent Findings

Ferroptosis was first reported as a separate modality of regulated cell death in 2008 and distinguished under its current name in 2012 after it was first induced with erastin. In the following decade, multiple other chemical agents were researched for their pro- or anti-ferroptotic properties. Complex organic structures with numerous aromatic moieties make up the majority of this list. This review fills a more overlooked niche by gathering, outlining and setting out conclusions regarding less prominent cases of ferroptosis induced by bioinorganic compounds and reported on within the last few years. The article contains a short summary of the application of bioinorganic chemicals based on gallium, several chalcogens, transition metals and elements known as human toxicants used for the purpose of evoking ferroptotic cell death in vitro or in vivo. These are used in the form of free ions, salts, chelates, gaseous and solid oxides or nanoparticles. Knowledge of how exactly these modulators promote or inhibit ferroptosis could be beneficial in the context of future therapies aimed against cancer or neurodegenerative diseases, respectively.

Nanomedicine-mediated ferroptosis targeting strategies for synergistic cancer therapy

Apoptosis-based treatment plays an important role in regulating the death of tumor cells (e.g., chemotherapy, radiotherapy, and immunotherapy). Nevertheless, cancer cells can escape surveillance from apoptosis-associated signaling by bypassing other biological pathways and thus result in considerable resistance to therapies. Significantly, ferroptosis, a newly identified type of regulated cell death that is characterized by iron-dependent and lipid peroxidation accumulation, has aroused great research interest in cancer therapy. Increasing approaches have been developed to induce ferroptosis of tumor cells, including using clinically approved drugs, experimentally used compounds, and nanomedicine formulations. More importantly, the emerging nanomedicine-based strategy has made great advances in tumor treatment because of the promising targeting efficacy and enhanced therapeutic effects. In this review, we mainly overview state-of-the-art research on nanomedicine-mediated ferroptosis targeting strategies for synergistic cancer therapies, such as immunotherapy, chemotherapy, radiotherapy, and photothermal therapy. The potential targeting mechanism of nanomedicine for ferroptosis induction was also included. Finally, the future development of nanomedicine in the field of ferroptosis-based cell death in tumor treatment will be envisioned, aiming to provide new insight for tumor treatment in the clinic.

A 'double locked' ratiometric fluorescent probe for detection of cysteine in a viscous system and its application in cancer cells

Intracellular viscosity is a physicochemical property that regulates the consequences of several biological progressions. Cysteine (Cys) is an important signaling molecule that commands many cellular activities, such as antioxidant generation. Predicting that both may be interconnected with a diversity of pathological processes, their contemporaneous measurement would be valuable for studying the pathological ailment of cells. Herein, we have synthesized a 'double locked' probe, acrylic acid 6-[4-(2-benzothiazol-2-yl-2-cyano-vinyl)-phenyl]-naphthalen-2-yl ester (ABN) for the detection of Cys in a viscous medium and explored its application to living cells that were exposed to dexamethasone to regulate the intracellular viscosity level. ABN displayed a satisfactory ratiometric (blue to orange) fluorescence response in solution and in living cells when Cys and viscosity coexisted. A turn-on fluorescence signal was visualized when the probe was individually treated with Cys and glycerol (a standard viscosity source). Therefore, we propose that ABN is a fluorescent probe that permits the monitoring of variations in intracellular viscosity and Cys levels in a biological environment, and it can be utilized in innumerable cellular damage models.

Environmental impact on carcinogenesis under BRCA1 haploinsufficiency

Cancer is the primary cause of human mortality in Japan since 1981. Although numerous novel therapies have been developed and applied in clinics, the number of deaths from cancer is still increasing worldwide. It is time to consider the strategy of cancer prevention more seriously. Here we propose a hypothesis that cancer can be side effects of long time-use of iron and oxygen and that carcinogenesis is an evolution-like cellular events to obtain "iron addiction with ferroptosis-resistance" where genes and environment interact each other. Among the recognized genetic risk factors for carcinogenesis, we here focus on BRCA1 tumor suppressor gene and how environmental factors, including daily life exposure and diets, may impact toward carcinogenesis under BRCA1 haploinsufficiency. Although mice models of BRCA1 mutants have not been successful for decades in generating phenotype mimicking the human counterparts, a rat model of BRCA1 mutant was recently established that reasonably mimics the human phenotype. Two distinct categories of oxidative stress, one by radiation and one by iron-catalyzed Fenton reaction, promoted carcinogenesis in Brca1 rat mutants. Furthermore, mitochondrial damage followed by alteration of iron metabolism finally resulted in ferroptosis-resistance of target cells in carcinogenesis. These suggest a possibility that cancer prevention by active pharmacological intervention may be possible for BRCA1 mutants to increase the quality of their life rather than preventive mastectomy and/or oophorectomy.

Mechanism of ferroptosis in traditional chinese medicine for clinical treatment: A review

Ferroptosis is an iron-dependent regulation of cell death driven by lipid peroxidation, which is intracellularly dependent on iron and independent of other metals, and morphologically, biochemically, and genetically distinct from apoptosis, necrosis, and autophagy. Ferroptosis is closely related to physiological and pathological processes, such as development, aging, and immunity, and it plays an important role in a variety of diseases. In many departments, traditional Chinese medicine plays an increasingly important role in their clinical treatment. In recent years, an increasing number of studies have been conducted on the mechanism of ferroptosis in traditional Chinese medicine. However, the role of ferroptosis in the clinical treatment of traditional Chinese medicine requires further exploration. This article mainly introduces the application of ferroptosis in studies of the mechanism of traditional Chinese medicine to help clinicians understand the current status of traditional Chinese medicine therapy for the treatment of ferroptosis-related diseases.

Ferroptosis-associated circular RNAs: Opportunities and challenges in the diagnosis and treatment of cancer

Ferroptosis is an emerging form of non-apoptotic regulated cell death which is different from cell death mechanisms such as autophagy, apoptosis and necrosis. It is characterized by iron-dependent lipid peroxide accumulation. Circular RNA (circRNA) is a newly studied evolutionarily conserved type of non-coding RNA with a covalent closed-loop structure. It exhibits universality, conservatism, stability and particularity. At present, the functions that have been studied and found include microRNA sponge, protein scaffold, transcription regulation, translation and production of peptides, etc. CircRNA can be used as a biomarker of tumors and is a hotspot in RNA biology research. Studies have shown that ferroptosis can participate in tumor regulation through the circRNA molecular pathway and then affect cancer progression, which may become a direction of cancer diagnosis and treatment in the future. This paper reviews the molecular biological mechanism of ferroptosis and the role of circular RNA in tumors and summarizes the circRNA related to ferroptosis in tumors, which may inspire research prospects for the precise prevention and treatment of cancer in the future.

Identification and validation of ferroptosis-related gene signature in intervertebral disc degeneration

Lower back pain (LBP) is a leading cause of disability in the elderly and intervertebral disc degeneration (IDD) is the major contributor to LBP. Ferroptosis is a newly discovered programmed cell death, characterized by iron-dependent lethal lipid peroxidation. Growing evidence has shown that ferroptosis plays important roles in various human diseases. However, the underlying mechanism of ferroptosis in IDD remains elusive. This study is aimed to uncover the key roles of ferroptosis in the pathogenesis and progression of IDD comprehensively. To investigate the ferroptosis related differentially expressed genes (FRDEGs) in IDD, we analyzed the microarray data from the Gene Expression Omnibus (GEO) database. Then we performed functional enrichment analysis and protein-protein interaction (PPI) network analysis, and screened out the hub FRDEGs. To further evaluate the predictive value of these hub FRDEGs, we performed ROC analysis based on the GSE124272 dataset. A total of 80 FRDEGs were identified, including 20 downregulated and 60 upregulated FRDEGs. The FRDEGs were primarily involved in the biological processes of response to chemical, and response to stress. KEGG pathway enrichment analysis showed that the FRDEGs were mainly involved in ferroptosis, TNF signaling pathway, HIF-1 signaling pathway, NOD-like receptor signaling pathway, and IL-17 signaling pathway. Ten hub OSRDEGs were obtained according to the PPI analysis, including HMOX1, KEAP1, MAPK1, HSPA5, TXNRD1, IL6, PPARA, JUN, HIF1A, DUSP1. The ROC analysis and RT-qPCR validation results suggested that most of the hub FRDEGs might be potential signature genes for IDD. This study reveals that ferroptosis might provide promising strategy for the diagnosis and treatment of IDD.

Molecular mechanisms of ferroptosis and relevance to inflammation

INTRODUCTION

Inflammation is a defensive response of the organism to irritation which is manifested by redness, swelling, heat, pain and dysfunction. The inflammatory response underlies the role of various diseases. Ferroptosis, a unique modality of cell death, driven by iron-dependent lipid peroxidation, is regulated by multifarious cellular metabolic pathways, including redox homeostasis, iron processing and metabolism of lipids, as well as various signaling pathways associated with diseases. A growing body of evidence suggests that ferroptosis is involved in inflammatory response, and targeting ferroptosis has great prospects in preventing and treating inflammatory diseases.

MATERIALS AND METHODS

Relevant literatures on ferroptosis, inflammation, inflammatory factors and inflammatory diseases published from January 1, 2010 to now were searched in PubMed database.

CONCLUSION

In this review, we summarize the regulatory mechanisms associated with ferroptosis, discuss the interaction between ferroptosis and inflammation, the role of mitochondria in inflammatory ferroptosis, and the role of targeting ferroptosis in inflammatory diseases. As more and more studies have confirmed the relationship between ferroptosis and inflammation in a wide range of organ damage and degeneration, drug induction and inhibition of ferroptosis has great potential in the treatment of immune and inflammatory diseases.

MicroRNA-27a Regulates Ferroptosis Through SLC7A11 to Aggravate Cerebral ischemia-reperfusion Injury

Cerebral ischemia-reperfusion (I/R) injury is an inevitable issue in the treatment of ischemic stroke, which has a high disability rate and seriously threatens the living quality of patients. Previous studies have demonstrated that ferroptosis, which plays a crucial role in ischemia-reperfusion injury, can be accelerated by microRNA-27a (miR-27a). However, the mechanism by which miR-27a regulates ferroptosis in cerebral ischemia-reperfusion injury remains unknown. In this study, Male Sprague-Dawley rats were subjected to a middle cerebral artery occlusion (MCAO), then restored blood flow. Neurological function score and TTC staining were used to evaluate brain tissue injury and the infarct volume. The relative expression level of miR-27a was detected by qPCR. The relative expression levels of glutathione peroxidase 4(GPx4), solute carrier family 7 member 11 (SLC7A11) proteins were analyzed by Western Blot. The contents of GSH, Fe and malonaldehyde (MDA) were detected by corresponding detection kits, and the target gene of miR-27a was confirmed by dual luciferase reporter gene technique. It was found the relative expression level of miR-27a was increased and ferroptosis was aggravated as reperfusion time went by. Also, brain tissue injury and ferroptosis were exacerbated with agomiR-27a intervention, while these effects were reversed with antagomiR-27a intervention. In addition, the combined intervention of agomiR-27a and Fer-1 alleviated the brain tissue injury and ferroptosis. The results of dual luciferase reporter gene technique indicated SLC7A11 as the target gene of miR-27a. In the current study, miR-27a upregulates ferroptosis to aggravate cerebral ischemia-reperfusion injury by SLC7A11.

Sorafenib versus Lenvatinib Causes Stronger Oxidative Damage to Membrane Lipids in Noncancerous Tissues of the Thyroid, Liver, and Kidney: Effective Protection by Melatonin and Indole-3-Propionic Acid

Sorafenib and lenvatinib are multi-targeted tyrosine kinase inhibitors which are currently approved to treat advanced hepatocellular carcinoma, renal cell carcinoma and radioiodine-refractory differentiated thyroid carcinoma. However this treatment is often limited due to common adverse events which may occur via oxidative stress. The study aims to compare sorafenib- and lenvatinib-induced oxidative damage to membrane lipids (lipid peroxidation, LPO) in homogenates of porcine noncancerous tissues of the thyroid, the liver, and the kidney and to check if it can be prevented by antioxidants melatonin and indole-3-propionic acid (IPA). Homogenates of individual tissues were incubated in the presence of sorafenib or lenvatinib (1 mM, 100 µM, 10 µM, 1 µM, 100 nM, 10 nM, 1 nM, 100 pM) together with/without melatonin (5.0 mM) or IPA (5.0 mM). The concentration of malondialdehyde + 4-hydroxyalkenals, as the LPO index, was measured spectrophotometrically. The incubation of tissue homogenates with sorafenib resulted in a concentration-dependent increase in LPO (statistically significant for concentrations of 1mM and 100 µM in the thyroid and the liver, and of 1 mM, 100 µM, and 10 µM in the kidney). The incubation of thyroid homogenates with lenvatinib did not change LPO level. In case of the liver and the kidney, lenvatinib increased LPO but only in its highest concentration of 1 mM. Melatonin and IPA reduced completely (to the level of control) sorafenib- and lenvatinib-induced LPO in all examined tissues regardless of the drug concentration. In conclusion, sorafenib comparing to lenvatinib is a stronger damaging agent of membrane lipids in noncancerous tissues of the thyroid, the liver, and the kidney. The antioxidants melatonin and IPA can be considered to be used in co-treatment with sorafenib and lenvatinib to prevent their undesirable toxicity occurring via oxidative stress.

Ferroptosis in lymphoma: Emerging mechanisms and a novel therapeutic approach

Unlike apoptosis, necroptosis, autophagy, and pyroptosis, ferroptosis represents a new type of cell death, which is characterized by iron-dependent lipid peroxidation. This process relies largely on the metabolite reactive oxygen species (ROS), phospholipids containing polyunsaturated fatty acids (PUFA-PL), transition metal iron, intra-, and intercellular signaling events, and environmental stress that regulate cellular metabolism and ROS levels. Recent studies show that ferroptosis plays an important role in tumorigenesis, tumor development, and the treatment of hematological malignancies, including lymphoma. Despite the constant emergence of new drugs, the differences in morphological features, immunophenotypes, biological patterns, rates of onset, and response to treatment in lymphoma pose major therapeutic challenges. Since lymphoma is associated with ferroptosis and shows sensitivity towards it, targeting the potential regulatory factors may regulate lymphoma progression. This has emerged as a research hotspot. This review summarizes the current knowledge on ferroptosis induction and resistance mechanisms, their roles and mechanistic details of ferroptosis in lymphoma suppression and immunity, and finally the treatment strategies for lymphoma by targeting ferroptosis.

Protein tyrosine phosphatase 1 protects human pancreatic cancer from erastin-induced ferroptosis

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a fatal malignancy due to the lack of early detection method, therapeutic drug and target. We noticed that the expression of Protein Tyrosine Phosphatase Mitochondria1(PTPMT1) is upregulated in PDAC. However, its role in pancreatic cancer remains unknown.

METHODS

We first analyzed the expression of PTPMT1 from 50 PDAC patients. Secondly, the survival proportions of different PTPMT1-expressed patients were analyzed. Then, the role and mechanism of PTPMT1 in PDAC were studied by lentivirus transduction system.

RESULTS

PTPMT1 was upregulated in PDAC and patients with high PTPMT1 expression displayed lower overall survival rate. Knockdown of PTPMT1 increased the sensitivity to erastin or RSL3 induced ferroptosis. Mechanically, knockdown of PTPMT1 resulted in upregulated Acyl-CoA Synthetase Long Chain Family Member 4 (ACSL4) and downregulated Solute Carrier Family 7 Member 11 (SLC7A11). In addition, SLC7A11 was upregulated in PDAC tumor tissue and correlated positively with the expression of PTPMT1. However, the expression of ACSL4 was downregulated in PDAC and negatively correlated with the expression of PTPMT1.

CONCLUSION

Our study demonstrates that PTPMT1 is upregulated in PDAC and PTPMT1 inhibits ferroptosis by suppressing the expression of ACSL4 and upregulating SLC7A11 in Panc-1 cells, suggesting PTPMT1 might be a potential prognosis biomarker and therapeutic target in PDAC.

Melatonin suppresses ferroptosis via activation of the Nrf2/HO-1 signaling pathway in the mouse model of sepsis-induced acute kidney injury

BACKGROUND

Ferroptosis is a regulated form of cell death. At present, the role of ferroptosis in sepsis-induced acute kidney injury (SAKI) has not been studied. Melatonin (MEL) has been reported to be an effective ferroptosis inhibitor, but it is unclear whether Melatonin can regulate ferroptosis in SAKI and whether its downstream mechanism correlates with the Nrf2/HO-1 pathway.

METHODS

The cecal ligation and puncture (CLP) method and LPS injection were used to induce SAKI in mouse model. Ferroptosis markers, including malondialdehyde (MDA) and glutathione peroxidase 4 (GPX4), were assessed. The ferroptosis inhibitor ferrostatin-1 (Fer-1) was used to explore the role of ferroptosis in SAKI. The GPX4 inhibitor RSL3, the HO-1 inhibitor zinc protoporphyrin(ZnPP), and the Nrf2 inhibitor ML385 were used to explore the specific mechanism of MEL in alleviation of SAKI.

RESULTS

The ferroptosis level was increased in the renal tissue of CLP- and LPS-induced septic mice. Both Fer-1 and MEL administration could suppress ferroptosis and attenuate kidney injury upon sepsis challenge. RSL3 partially blocked MEL's beneficial renal-protective effects. MEL up-regulated Nrf2 and HO-1 in CLP mice, and both ZnPP and ML385 blocked the MEL-mediated effects of ferroptosis inhibition and renal protection.

CONCLUSIONS

Ferroptosis aggravates SAKI. Melatonin treatment suppresses ferroptosis and alleviates kidney injury in the context of experimental sepsis by upregulating Nrf2/HO-1 pathway.