Redox biology of regulated cell death in cancer: A focus on necroptosis and ferroptosis

A bibliometric analysis of programmed cell death in oral cancer literature: research patterns and emerging trends (2000-2024)

BACKGROUND

Programmed cell death (PCD) plays a crucial role in oral cancer pathogenesis and treatment. However, a comprehensive bibliometric analysis of the global research landscape in this field has not been conducted. This study aims to analyze the evolution and current trends of PCD research in oral cancer from 2000 to 2024.

METHODS

Publications were retrieved from the Web of Science Core Collection database using relevant keywords related to oral cancer and PCD. VOSviewer 1.6.20 and CiteSpace 6.1R6 software were employed to conduct bibliometric analysis, including publication trends, citation analysis, co-authorship networks, keyword co-occurrence, and research hotspots. The time span was set from January 2000 to December 2024.

RESULTS

A total of 963 publications were identified and analyzed. The annual publication output showed a steady increase, with a significant growth rate after 2010, dividing the study period into three distinct phases. The most productive countries were China (58.42%), South Korea (12.27%), and Japan (10.04%), with China Medical University and Kaohsiung Medical University being the leading institutions. Research hotspots evolved from traditional apoptosis studies to emerging forms of PCD such as autophagy, ferroptosis, and pyroptosis. Keyword analysis revealed three major research clusters: basic molecular mechanisms (centered around ROS and oxidative stress), clinical aspects (including prognosis and cell proliferation), and cell death pathways. Citation burst analysis identified emerging trends in targeting multiple PCD pathways simultaneously for oral cancer therapy, with special focus on treatment resistance and survival.

CONCLUSION

This bibliometric analysis provides a comprehensive overview of global research trends in PCD and oral cancer over the past two decades. The findings highlight the shift from basic mechanistic studies focusing on apoptosis to more diverse PCD pathways and translational research. Emerging research directions include the exploration of synergistic mechanisms among multiple PCD pathways, development of AI-based personalized treatment plans, investigation of microenvironment regulation of PCD, and application of novel drug delivery systems. These trends demonstrate the field's evolution toward more integrated, personalized approaches in oral cancer treatment. This study offers valuable insights for researchers and funding agencies to identify research gaps and potential collaboration opportunities in this rapidly developing field.

Nanomaterial-based regulation of redox metabolism for enhancing cancer therapy

Altered redox metabolism is one of the hallmarks of tumor cells, which not only contributes to tumor proliferation, metastasis, and immune evasion, but also has great relevance to therapeutic resistance. Therefore, regulation of redox metabolism of tumor cells has been proposed as an attractive therapeutic strategy to inhibit tumor growth and reverse therapeutic resistance. In this respect, nanomedicines have exhibited significant therapeutic advantages as intensively reported in recent studies. In this review, we would like to summarize the latest advances in nanomaterial-assisted strategies for redox metabolic regulation therapy, with a focus on the regulation of redox metabolism-related metabolite levels, enzyme activity, and signaling pathways. In the end, future expectations and challenges of such emerging strategies have been discussed, hoping to enlighten and promote their further development for meeting the various demands of advanced cancer therapies. It is highly expected that these therapeutic strategies based on redox metabolism regulation will play a more important role in the field of nanomedicine.

Sodium-glucose cotransporter 2 inhibitors induce anti-inflammatory and anti-ferroptotic shift in epicardial adipose tissue of subjects with severe heart failure

BACKGROUND

Sodium-glucose cotransporter 2 inhibitors (SGLT-2i) are glucose-lowering agents used for the treatment of type 2 diabetes mellitus, which also improve heart failure and decrease the risk of cardiovascular complications. Epicardial adipose tissue (EAT) dysfunction was suggested to contribute to the development of heart failure. We aimed to elucidate a possible role of changes in EAT metabolic and inflammatory profile in the beneficial cardioprotective effects of SGLT-2i in subjects with severe heart failure.

METHODS

26 subjects with severe heart failure, with reduced ejection fraction, treated with SGLT-2i versus 26 subjects without treatment, matched for age (54.0 ± 2.1 vs. 55.3 ± 2.1 years, n.s.), body mass index (27.8 ± 0.9 vs. 28.8 ± 1.0 kg/m2, n.s.) and left ventricular ejection fraction (20.7 ± 0.5 vs. 23.2 ± 1.7%, n.s.), who were scheduled for heart transplantation or mechanical support implantation, were included in the study. A complex metabolomic and gene expression analysis of EAT obtained during surgery was performed.

RESULTS

SGLT-2i ameliorated inflammation, as evidenced by the improved gene expression profile of pro-inflammatory genes in adipose tissue and decreased infiltration of immune cells into EAT. Enrichment of ether lipids with oleic acid noted on metabolomic analysis suggests a reduced disposition to ferroptosis, potentially further contributing to decreased oxidative stress in EAT of SGLT-2i treated subjects.

CONCLUSIONS

Our results show decreased inflammation in EAT of patients with severe heart failure treated by SGLT-2i, as compared to patients with heart failure without this therapy. Modulation of EAT inflammatory and metabolic status could represent a novel mechanism behind SGLT-2i-associated cardioprotective effects in patients with heart failure.

Recent advancements in nanomaterial-mediated ferroptosis-induced cancer therapy: Importance of molecular dynamics and novel strategies

Ferroptosis is a novel type of controlled cell death resulting from an imbalance between oxidative harm and protective mechanisms, demonstrating significant potential in combating cancer. It differs from other forms of cell death, such as apoptosis and necrosis. Molecular therapeutics have hard time playing the long-acting role of ferroptosis induction due to their limited water solubility, low cell targeting capacity, and quick metabolism in vivo. To this end, small molecule inducers based on biological factors have long been used as strategy to induce cell death. Research into ferroptosis and advancements in nanotechnology have led to the discovery that nanomaterials are superior to biological medications in triggering ferroptosis. Nanomaterials derived from iron can enhance ferroptosis induction by directly releasing large quantities of iron and increasing cell ROS levels. Moreover, utilizing nanomaterials to promote programmed cell death minimizes the probability of unfavorable effects induced by mutations in cancer-associated genes such as RAS and TP53. Taken together, this review summarizes the molecular mechanisms involved in ferroptosis along with the classification of ferroptosis induction. It also emphasized the importance of cell organelles in the control of ferroptosis in cancer therapy. The nanomaterials that trigger ferroptosis are categorized and explained. Iron-based and noniron-based nanomaterials with their characterization at the molecular and cellular levels have been explored, which will be useful for inducing ferroptosis that leads to reduced tumor growth. Within this framework, we offer a synopsis, which traverses the well-established mechanism of ferroptosis and offers practical suggestions for the design and therapeutic use of nanomaterials.

Targeting inflammation as cancer therapy

Inflammation has accompanied human beings since the emergence of wounds and infections. In the past decades, numerous efforts have been undertaken to explore the potential role of inflammation in cancer, from tumor development, invasion, and metastasis to the resistance of tumors to treatment. Inflammation-targeted agents not only demonstrate the potential to suppress cancer development, but also to improve the efficacy of other therapeutic modalities. In this review, we describe the highly dynamic and complex inflammatory tumor microenvironment, with discussion on key inflammation mediators in cancer including inflammatory cells, inflammatory cytokines, and their downstream intracellular pathways. In addition, we especially address the role of inflammation in cancer development and highlight the action mechanisms of inflammation-targeted therapies in antitumor response. Finally, we summarize the results from both preclinical and clinical studies up to date to illustrate the translation potential of inflammation-targeted therapies.

The dance of macrophage death: the interplay between the inevitable and the microenvironment

Macrophages are highly plastic cells ubiquitous in various tissues, where they perform diverse functions. They participate in the response to pathogen invasion and inflammation resolution following the immune response, as well as the maintenance of homeostasis and proper tissue functions. Macrophages are generally considered long-lived cells with relatively strong resistance to numerous cytotoxic factors. On the other hand, their death seems to be one of the principal mechanisms by which macrophages perform their physiological functions or can contribute to the development of certain diseases. In this review, we scrutinize three distinct pro-inflammatory programmed cell death pathways - pyroptosis, necroptosis, and ferroptosis - occurring in macrophages under specific circumstances, and explain how these cells appear to undergo dynamic yet not always final changes before ultimately dying. We achieve that by examining the interconnectivity of these cell death types, which in macrophages seem to create a coordinated and flexible system responding to the microenvironment. Finally, we discuss the complexity and consequences of pyroptotic, necroptotic, and ferroptotic pathway induction in macrophages under two pathological conditions - atherosclerosis and cancer. We summarize damage-associated molecular patterns (DAMPs) along with other microenvironmental factors, macrophage polarization states, associated mechanisms as well as general outcomes, as such a comprehensive look at these correlations may point out the proper methodologies and potential therapeutic approaches.

Natural compounds efficacy in Ophthalmic Diseases: A new twist impacting ferroptosis

Ferroptosis, a distinct form of cell death, is characterized by the iron-mediated oxidation of lipids and is finely controlled by multiple cellular metabolic pathways. These pathways encompass redox balance, iron regulation, mitochondrial function, as well as amino acid, lipid, and sugar metabolism. Additionally, various disease-related signaling pathways also play a role in the regulation of ferroptosis. In recent years, with the introduction of the concept of ferroptosis and the deepening of research on its mechanism, ferroptosis is closely related to various biological conditions of eye diseases, including eye organ development, aging, immunity, and cancer. This article reviews the development of the concept of ferroptosis, the mechanism of ferroptosis, and its latest research progress in ophthalmic diseases and reviews the research on ferroptosis in ocular diseases within the framework of metabolism, active oxygen biology, and iron biology. Key regulators and mechanisms of ferroptosis in ocular diseases introduce important concepts and major open questions in the field of ferroptosis and related natural compounds. It is hoped that in future research, further breakthroughs will be made in the regulation mechanism of ferroptosis and the use of ferroptosis to promote the treatment of eye diseases. At the same time, natural compounds may be the direction of new drug development for the potential treatment of ferroptosis in the future. Open up a new way for clinical ophthalmologists to research and prevent diseases.

Melanoma biology and treatment: a review of novel regulated cell death-based approaches

The incidence of melanoma, the most lethal form of skin cancer, has increased due to ultraviolet exposure. The treatment of advanced melanoma, particularly metastatic cases, remains challenging with poor outcomes. Targeted therapies involving BRAF/MEK inhibitors and immunotherapy based on anti-PD1/anti-CTLA4 antibodies have achieved long-term survival rates of approximately 50% for patients with advanced melanoma. However, therapy resistance and inadequate treatment response continue to hinder further breakthroughs in treatments that increase survival rates. This review provides an introduction to the molecular-level pathogenesis of melanoma and offers an overview of current treatment options and their limitations. Cells can die by either accidental or regulated cell death (RCD). RCD is an orderly cell death controlled by a variety of macromolecules to maintain the stability of the internal environment. Since the uncontrolled proliferation of tumor cells requires evasion of RCD programs, inducing the RCD of melanoma cells may be a treatment strategy. This review summarizes studies on various types of nonapoptotic RCDs, such as autophagy-dependent cell death, necroptosis, ferroptosis, pyroptosis, and the recently discovered cuproptosis, in the context of melanoma. The relationships between these RCDs and melanoma are examined, and the interplay between these RCDs and immunotherapy or targeted therapy in patients with melanoma is discussed. Given the findings demonstrating melanoma cell death in response to different stimuli associated with these RCDs, the induction of RCD shows promise as an integral component of treatment strategies for melanoma.

Mechanism study of oleanolic acid derivative, K73-03, inducing cell apoptosis in hepatocellular carcinoma

Oleanolic acid (3β-hydroxyolean-12-en-28-oic acid, OA) is a kind of pentacyclic triterpene, which widely distributes in nature. OA possesses a powerful anti-cancer effect; however, its low solubility limits its bioavailability and application. In this study, a new OA derivative, K73-03, was used to determine its effect on liver cancer cells and detailed molecular mechanisms. Here, we show that K73-03 may lead to the disorder of mitochondria in HepG2 cells, leading to excessive ROS production and apoptosis in cells. Meanwhile, K73-03 could induce cell apoptosis by inhibiting JAK2/STAT3 pathway and NF-κB/P65 pathway. Collectively, this study may provide a preliminary basis for further cancer treatment of hepatocellular carcinoma.

Acetylshikonin induces necroptosis via the RIPK1/RIPK3-dependent pathway in lung cancer

Despite advances in therapeutic strategies, lung cancer remains the leading cause of cancer-related death worldwide. Acetylshikonin is a derivative of the traditional Chinese medicine Zicao and presents a variety of anticancer properties. However, the effects of acetylshikonin on lung cancer have not been fully understood yet. This study explored the mechanisms underlying acetylshikonin-induced cell death in non-small cell lung cancer (NSCLC). Treating NSCLC cells with acetylshikonin significantly reduced cell viability, as evidenced by chromatin condensation and the appearance of cell debris. Acetylshikonin has also been shown to increase cell membrane permeability and induce cell swelling, leading to an increase in the population of necrotic cells. When investigating the mechanisms underlying acetylshikonin-induced cell death, we discovered that acetylshikonin promoted oxidative stress, decreased mitochondrial membrane potential, and promoted G2/M phase arrest in lung cancer cells. The damage to NSCLC cells induced by acetylshikonin resembled results involving alterations in the cell membrane and mitochondrial morphology. Our analysis of oxidative stress revealed that acetylshikonin induced lipid oxidation and down-regulated the expression of glutathione peroxidase 4 (GPX4), which has been associated with necroptosis. We also determined that acetylshikonin induces the phosphorylation of receptor-interacting serine/threonine-protein kinase 1 (RIPK1)/RIPK3 and mixed lineage kinase domain-like kinase (MLKL). Treatment with RIPK1 inhibitors (necrostatin-1 or 7-Cl-O-Nec-1) significantly reversed acetylshikonin-induced MLKL phosphorylation and NSCLC cell death. These results indicate that acetylshikonin activated the RIPK1/RIPK3/MLKL cascade, leading to necroptosis in NSCLC cells. Our findings indicate that acetylshikonin reduces lung cancer cells by promoting G2/M phase arrest and necroptosis.

Hyperbaric oxygen improves cerebral ischemia-reperfusion injury in rats via inhibition of ferroptosis

BACKGROUND

Our previous study found that hyperbaric oxygen (HBO) attenuated cognitive impairment in mice induced by cerebral ischemia-reperfusion injury (CIRI). However, its mechanism of action is not fully understood. In this study, we aimed to establish a rat model of cerebral ischemia-reperfusion, explore the possible role of ferroptosis in the pathogenesis of CIRI, and observe the effect of HBO on ferroptosis-mediated CIRI.

METHODS

Sprague Dawley (SD) rats were randomly divided into control, model, Ferrostatin-1 (Fer-1), HBO and Fer-1+ HBO groups. Morris water maze, myelin basic protein (MBP) and β-tubulin immunoreactivity were assessed to evaluate the neuroprotective effects of HBO on cerebral ischemia reperfusion injury. Ferroptosis were examined to investigate the mechanism underlying the effects of HBO.

RESULTS

Our result showed that Fer-1 and HBO improved learning and memory ability in the navigation trail and probe trail of the Morris water maze and increased MBP and β-tubulin immunoreactivity of the cortex in the model rats. The levels of ferritin, malondialdehyde (MDA) and glutathione (GSH) in the serum were also reversed by Fer-1 and HBO treatment. Mitochondrial cristae dissolution and vacuolization were observed in the model group by transmission electron microscopy and these conditions were improved in the Fer-1 and HBO groups. Furthermore, Fer-1 and HBO treatment reversed Prostaglandin-Endoperoxide Synthase 2 (PTGS2), Iron Responsive Element Binding Protein 2 (IREB2), acyl-CoA synthetase long chain family member 4 (ACSL4) and Solute Carrier Family 7 Member 11 (SLC7A11) mRNA levels and Transferrin Receptor 1 (TFR1), ferritin light chain (FTL), ferritin heavy chain 1 (FTH1), glutathione peroxidase 4 (GPX4), Nuclear factor E2-related factor 2 (Nrf2), lysophosphatidylcholine acyltransferase 3 (LPCAT3), c-Jun N-terminal kinase (JNK), phosphorylated c-Jun N-terminal kinase (P-JNK) phosphorylated Extracellular signal-regulated protein kinase (P-ERK) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK) protein levels. The above changes were more pronounced in Fer-1+ HBOGroup.

DISCUSSION

The results of the present study indicated that HBO improves cerebral ischemia-reperfusion injury in rats, which may be related to inhibition of ferroptosis. This also means that ferroptosis may become a new target of HBO against CIRI.

Compound 5 alleviated acute kidney injury without affecting the antitumor effect after cisplatin treatment

Despite being a powerful weapon against cancer cells, cisplatin's therapeutic potential is hampered by numerous adverse reactions, including acute kidney injury (AKI). Compound 5 has 3-SH fragments at the end of the vertical short alkyl side chain, which is an ROS scavenger synthesized. In this study, we evaluated the protective effect of compound 5 on the kidney after cisplatin administration and its mechanism. The results founded that compound 5 can alleviate serum urea nitrogen and serum creatinine induced by cisplatin administration in vivo. In addition, histopathological analysis of the kidneys showed that compound 5 significantly reduced cisplatin-induced (Cis-induced) renal toxicity compared with the cisplatin group. A mechanism study showed that compound 5 significantly reduces NOX4 levels, improves the activity of antioxidant enzymes (SOD and GSH-Px), reduces Malondialdehyde (MDA) levels, increases the total antioxidant level, reduces oxidative stress, and thus reduces kidney tissue damage. At the same time, compound 5 activated the Nrf2 signaling pathway. In addition, it can increase the expression of Bax, reduce the expression of Bcl-2 and caspase-3, a marker of apoptosis, which is beneficial to the survival of kidney cells. Additionally, compound 5 did not interfere with the antitumor effects of cisplatin in in vivo xenotransplantation models.

JAK/STAT signaling and cellular iron metabolism in hepatocellular carcinoma: therapeutic implications

Iron metabolism plays a crucial role in the development and progression of hepatocellular carcinoma (HCC), the most common type of primary liver cancer. Iron is an essential micronutrient that is involved in many physiological processes, including oxygen transport, DNA synthesis, and cellular growth and differentiation. However, excessive iron accumulation in the liver has been linked to oxidative stress, inflammation, and DNA damage, which can increase the risk of HCC. Studies have shown that iron overload is common in patients with HCC and that it is associated with a poor prognosis and reduced survival rates. Various iron metabolism-related proteins and signaling pathways such as the JAK/STAT pathway are dysregulated in HCC. Moreover, reduced hepcidin expression was reported to promote HCC in a JAK/STAT pathway-dependent manner. Therefore, it is important to understand the crosstalk between iron metabolism and the JAK/STAT pathway to prevent or treat iron overload in HCC. Iron chelators can bind to iron and remove it from the body, but its effect on JAK/STAT pathway is unclear. Also, HCC can be targeted by using the JAK/STAT pathway inhibitors, but their effect on hepatic iron metabolism is not known. In this review, for the first time, we focus on the role of the JAK/STAT signaling pathway in regulating cellular iron metabolism and its association with the development of HCC. We also discuss novel pharmacological agents and their therapeutic potential in manipulating iron metabolism and JAK/STAT signaling in HCC.

Effect of doramectin on programmed cell death pathway in glioma cells

PURPOSE

Doramectin (DRM) is a kind of avermectin drugs, and it has been shown that DRM has anti-cancer effects. However, the molecular mechanism of DRM in programmed cell death (PCD) aspects is still unclear. The objective of this study was to confirm whether DRM induced PCD in glioma cells.

METHODS

In this experiment, the MTT assay and Ki-67 assay were used to detect in vitro cell viability and in vivo tumor proliferation. Then, the effect of DRM on PCD was analyzed by transcriptome comparison. Next, Endogenous apoptosis was detected by transmission electron microscopy (TEM), the DNA gel electrophoresis, JC-1 assay, western blotting and qRT-PCR. Meanwhile, necroptosis was detected by TEM, Hoechst 33342, FITC and PI staining assay, western blotting.

RESULTS

We found DRM induced apoptosis through Bcl-2/Bax/Caspase-3 pathway. And, DRM induced ROS overproduction, then ROS caused necroptosis through RIPK1/RIPK3/MLKL pathway, Mitochondria acted as a bridge between the two pathways.

CONCLUSION

Our research provided new insight with the function of anti-cancer of DRM. These results demonstrated DRM may be used as potential therapeutic agents inducing apoptosis and necroptosis for cancer therapy.

Therapeutic effect of trace elements on multiple myeloma and mechanisms of cancer process

In the human body, trace elements and other micronutrients play a vital role in growth, health and immune system function. The trace elements are Iron, Manganese, Copper, Iodine, Zinc, Cobalt, Fluoride, and Selenium. Estimating the serum levels of trace elements in hematologic malignancy patients can determine the severity of the tumor. Multiple myeloma (MM) is a hematopoietic malignancy and is characterized by plasma cell clonal expansion in bone marrow. Despite the advances in treatment methods, myeloma remains largely incurable. In addition to conventional medicine, treatment is moving toward less expensive noninvasive alternatives. One of the alternative treatments is the use of dietary supplements. In this review, we focused on the effect of three trace elements including iron, zinc and selenium on important mechanisms such as the immune system, oxidative and antioxidant factors and cell cycle. Using some trace minerals in combination with approved drugs can increase patients' recovery speed. Trace elements can be used as not only a preventive but also a therapeutic tool, especially in reducing inflammation in hematological cancers such as multiple myeloma. We hope that the prospect of the correct use of trace element supplements in the future could be promising for the treatment of diseases.

Oxidative Stress Initiates Receptor-Interacting Protein Kinase-3/Mixed Lineage Kinase Domain-Like-Mediated Corneal Epithelial Necroptosis and Nucleotide-Binding Oligomerization Domain-Like Receptor Protein 3 Inflammasome Signaling during Fungal Keratitis

Fungal keratitis remains a major cause of severe visual loss in developing countries because of limited choices of therapy. The progression of fungal keratitis is a race between the innate immune system and the outgrowth of fungal conidia. Programmed necrosis (necroptosis), a type of proinflammatory cell death, has been recognized as a critical pathologic change in several diseases. However, the role and potential regulatory mechanisms of necroptosis have not been investigated in corneal diseases. The current study showed, for the first time, that fungal infection triggered significant corneal epithelial necroptosis in human/mouse/in vitro models. Moreover, a reduction in excessive reactive oxygen species release effectively prevented necroptosis. NLRP3 knockout did not affect necroptosis in vivo. In contrast, ablation of necroptosis via RIPK3 knockout significantly delayed migration and inhibited the nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome in macrophages, which enhanced the progression of fungal keratitis. Taking these findings together, the study indicated that overproduction of reactive oxygen species in fungal keratitis leads to significant necroptosis in the corneal epithelium. Furthermore, the necroptotic stimuli-mediated NLRP3 inflammasome serves as a driving force in host defense against fungal infection.

Impact of HepG2 Cells Glutathione Depletion on Neutral Sphingomyelinases mRNA Levels and Activity

Liver cancer is a prevalent form of cancer worldwide. While research has shown that increasing sphingomyelin (SM) hydrolysis by activating the cell surface membrane-associated neutral sphingomyelinase 2 (nSMase2) can control cell proliferation and apoptosis, the role of total glutathione depletion in inducing tumor cell apoptosis via nSMase2 activation is still under investigation. Conversely, glutathione-mediated inhibition of reactive oxygen species (ROS) accumulation is necessary for the enzymatic activity of nSMase1 and nSMase3, increased ceramide levels, and cell apoptosis. This study evaluated the effects of depleting total glutathione in HepG2 cells using buthionine sulfoximine (BSO). The study assessed nSMases RNA levels and activities, intracellular ceramide levels, and cell proliferation using RT-qPCR, Amplex red neutral sphingomyelinase fluorescence assay, and colorimetric assays, respectively. The results indicated a lack of nSMase2 mRNA expression in treated and untreated HepG2 cells. Depletion of total glutathione resulted in a significant increase in mRNA levels but a dramatic reduction in the enzymatic activity of nSMase1 and nSMase3, a rise in ROS levels, a decrease in intracellular levels of ceramide, and an increase in cell proliferation. These findings suggest that total glutathione depletion may exacerbate liver cancer (HCC) and not support using total glutathione-depleting agents in HCC management. It is important to note that these results are limited to HepG2 cells, and further studies are necessary to determine if these effects will also occur in other cell lines. Additional research is necessary to explore the role of total glutathione depletion in inducing tumor cell apoptosis.

Novel Insight into Ferroptosis in Kidney Diseases

BACKGROUND

Various kidney diseases such as acute kidney injury, chronic kidney disease, polycystic kidney disease, renal cancer, and kidney stones, are an important part of the global burden, bringing a huge economic burden to people around the world. Ferroptosis is a type of nonapoptotic iron-dependent cell death caused by the excess of iron-dependent lipid peroxides and accompanied by abnormal iron metabolism and oxidative stress. Over the past few decades, several studies have shown that ferroptosis is associated with many types of kidney diseases. Studying the mechanism of ferroptosis and related agonists and inhibitors may provide new ideas and directions for the treatment of various kidney diseases.

SUMMARY

In this review, we discuss the differences between ferroptosis and other types of cell death such as apoptosis, necroptosis, pyroptosis, cuprotosis, pathophysiological features of the kidney, and ferroptosis-induced kidney injury. We also provide an overview of the molecular mechanisms involved in ferroptosis and events that lead to ferroptosis. Furthermore, we summarize the possible clinical applications of this mechanism among various kidney diseases.

KEY MESSAGE

The current research suggests that future therapeutic efforts to treat kidney ailments would benefit from a focus on ferroptosis.

Ferroptosis-modulating small molecules for targeting drug-resistant cancer: Challenges and opportunities in manipulating redox signaling

Ferroptosis is an iron-dependent cell death program that is characterized by excessive lipid peroxidation. Triggering ferroptosis has been proposed as a promising strategy to fight cancer and overcome drug resistance in antitumor therapy. Understanding the molecular interactions and structural features of ferroptosis-inducing compounds might therefore open the door to efficient pharmacological strategies against aggressive, metastatic, and therapy-resistant cancer. We here summarize the molecular mechanisms and structural requirements of ferroptosis-inducing small molecules that target central players in ferroptosis. Focus is placed on (i) glutathione peroxidase (GPX) 4, the only GPX isoenzyme that detoxifies complex membrane-bound lipid hydroperoxides, (ii) the cystine/glutamate antiporter system Xc - that is central for glutathione regeneration, (iii) the redox-protective transcription factor nuclear factor erythroid 2-related factor (NRF2), and (iv) GPX4 repression in combination with induced heme degradation via heme oxygenase-1. We deduce common features for efficient ferroptotic activity and highlight challenges in drug development. Moreover, we critically discuss the potential of natural products as ferroptosis-inducing lead structures and provide a comprehensive overview of structurally diverse biogenic and bioinspired small molecules that trigger ferroptosis via iron oxidation, inhibition of the thioredoxin/thioredoxin reductase system or less defined modes of action.

RNA-binding domain 2 of nucleolin is important for the autophagy induction of curcumol in nasopharyngeal carcinoma cells

BACKGROUND & AIMS

Excessive autophagy induces cell death and is regarded as the treatment of cancer therapy. We have confirmed that the anti-cancer mechanism of curcumol is related to autophagy induction. As the main target protein of curcumol, RNA binding protein nucleolin (NCL) interacted with many tumor promoters accelerating tumor progression. However, the role of NCL in cancer autophagy and in curcumol's anti-tumor effects haven't elucidated. The purpose of the study is to identify the role of NCL in nasopharyngeal carcinoma autophagy and reveal the immanent mechanisms of NCL played in cell autophagy.

METHODS & RESULTS

In the current study, we have found that NCL was markedly upregulated in nasopharyngeal carcinoma (NPC) cells. NCL overexpression effectively attenuated the level of autophagy in NPC cells, and NCL silence or curcumol treatment obviously aggravated the autophagy of NPC cells. Moreover, the attenuation of NCL by curcumol lead a significant suppression on PI3K/AKT/mTOR signaling pathway in NPC cells. Mechanistically, NCL was found to be directly interact with AKT and accelerate AKT phosphorylation, which caused the activation of the PI3K/AKT/mTOR pathway. Meanwhile, the RNA Binding Domain (RBD) 2 of NCL interacts with Akt, which was also influenced by curcumol. Notably, the RBDs of NCL delivered AKT expression was related with cell autophagy in the NPC.

CONCLUSION

The results demonstrated that NCL regulated cell autophagy was related with interaction of NCL and Akt in NPC cells. The expression of NCL play an important role in autophagy induction and further found that was associated with its effect on NCL RNA-binding domain 2. This study may provide a new perspective on the target protein studies for natural medicines and confirm the effect of curcumol not only regulating the expression of its target protein, but also influencing the function domain of its target protein.

Regulation of ncRNAs involved with ferroptosis in various cancers

As a special pattern of programmed cell death, ferroptosis is reported to participate in several processes of tumor progression, including regulating proliferation, suppressing apoptotic pathways, increasing metastasis, and acquiring drug resistance. The marked features of ferroptosis are an abnormal intracellular iron metabolism and lipid peroxidation that are pluralistically modulated by ferroptosis-related molecules and signals, such as iron metabolism, lipid peroxidation, system Xc−, GPX4, ROS production, and Nrf2 signals. Non-coding RNAs (ncRNAs) are a type of functional RNA molecules that are not translated into a protein. Increasing studies demonstrate that ncRNAs have a diversity of regulatory roles in ferroptosis, thus influencing the progression of cancers. In this study, we review the fundamental mechanisms and regulation network of ncRNAs on ferroptosis in various tumors, aiming to provide a systematic understanding of recently emerging non-coding RNAs and ferroptosis.

Mycobacterium tuberculosis Rv1324 Protein Contributes to Mycobacterial Persistence and Causes Pathological Lung Injury in Mice by Inducing Ferroptosis

Mycobacterium tuberculosis (Mtb) is the pathogenic agent of tuberculosis (TB). Intracellular survival plays a central role in the pathogenesis of Mtb, a process that depends on an array of virulence factors for Mtb to colonize and proliferate within a host. Reactive nitrogen and oxygen species (RNS and ROS) are among the most effective antimycobacterial molecules generated by the host during infection. However, Mtb has evolved a number of proteins and enzymes to detoxify ROS and RNS. Secretory protein Rv1324, as a possible thioredoxin, might also have oxidoreductase activity against ROS and RNS during Mtb infection, and it is a potential virulence factor of Mtb. In this study, we investigated the biochemical properties of Mtb Rv1324 and its role in mycobacterial survival and virulence. The results showed that the Rv1324 protein had antioxidant activity and increased the survival of M. smegmatis that was exposed to ROS and RNS. In addition, Rv1324 enhanced the colonization ability of M. smegmatis in the lungs of mice. Further, mice infected with M. smegmatis harboring Rv1324 exhibited pathological injury and inflammation in the lung, which was mediated by ferroptosis. In summary, this study advances our understanding of the mechanisms of mycobacterial survival and pathogenesis, and it reveals a novel target for TB treatment. IMPORTANCE The intracellular survival of M. tuberculosis (Mtb) plays a crucial role in its pathogenesis, which depends on various Mtb oxidoreductases that are resistant to reactive oxygen and nitrogen species (ROS and RNS) that are generated by the host during Mtb infection. Secretory protein Rv1324 is a potential virulence factor of Mtb and is a possible thioredoxin that has oxidoreductase activity against ROS and RNS during Mtb infection. We investigated the biochemical properties of Mtb Rv1324 and its role in mycobacterial survival and virulence. It was confirmed that the Rv1324 protein had antioxidant activity and an increased mycobacterial resistance to ROS and RNS. In addition, Rv1324 enhanced mycobacterial persistence and induced pathological injury and inflammation in the lungs of mice by activating ferroptosis. This study advances our understanding of the mechanisms of mycobacterial survival and pathogenesis, and it reveals a novel target for TB treatment.

Ferroptosis: mechanisms and advances in ocular diseases

As an essential trace element in the body, iron is critical for the maintenance of organismal metabolism. Excessive iron facilitates reactive oxygen species generation and inflicts damage on cells and tissues. Ferroptosis, a newly identified iron-dependent type of programmed cell death, has been implicated in a broad set of metabolic disorders. Ferroptosis is mainly characterized by excess iron accumulation, elevated lipid peroxides and reactive oxygen species, and reduced levels of glutathione and glutathione peroxidase 4. The vast emerging literature on ferroptosis has shown that numerous diseases, such as cancers, neurodegeneration, and autoimmune diseases, are associated with ferroptosis. Meanwhile, recent studies have confirmed the relationship between ferroptosis and eye diseases including keratopathy, cataract, glaucoma, retinal ischemia-reperfusion injury, age-related macular degeneration, retinitis pigmentosa, diabetic retinopathy, and retinoblastoma, indicating the critical role of ferroptosis in ocular diseases. In this article, we introduce the primary signaling pathways of ferroptosis and review current advances in research on ocular diseases involving iron overload and ferroptosis. Furthermore, several unanswered questions in the area are raised. Addressing these unanswered questions promises to provide new insights into preventing, controlling, and treating not only ocular diseases but also a variety of other diseases in the near future.

The molecular mechanism of ferroptosis and its role in COPD

Ferroptosis, a new type of cell death, is mainly characterized by intracellular iron accumulation and lipid peroxidation. The complex regulatory network of iron metabolism, lipid metabolism, amino acid metabolism, p53-related signaling, and Nrf2-related signaling factors is involved in the entire process of ferroptosis. It has been reported that ferroptosis is involved in the pathogenesis of neurological diseases, cancer, and ischemia-reperfusion injury. Recent studies found that ferroptosis is closely related to the pathogenesis of COPD, which, to some extent, indicates that ferroptosis is a potential therapeutic target for COPD. This article mainly discusses the related mechanisms of ferroptosis, including metabolic regulation and signaling pathway regulation, with special attention to its role in the pathogenesis of COPD, aiming to provide safe and effective therapeutic targets for chronic airway inflammatory diseases.

The Role of Ferroptosis in Blood-Brain Barrier Injury

The blood-brain barrier (BBB) is an important barrier that maintains homeostasis within the central nervous system. Brain microvascular endothelial cells are arranged to form vessel walls and express tight junctional complexes that limit the paracellular pathways of the BBB and therefore play a crucial role in ensuring brain function. These vessel walls tightly regulate the movement of ions, molecules, and cells between the blood and the brain, which protect the neural tissue from toxins and pathogens. Primary damage caused by BBB dysfunction can disrupt the expression of tight junctions, transport proteins and leukocyte adhesion molecules, leading to brain edema, disturbances in ion homeostasis, altered signaling and immune infiltration, which can lead to neuronal cell death. Various neurological diseases are known to cause BBB dysfunction, but the mechanism that causes this disorder is not clear. Recently, ferroptosis has been found to play an important role in BBB dysfunction. Ferroptosis is a new form of regulatory cell death, which is caused by the excessive accumulation of lipid peroxides and iron-dependent reactive oxygen species. This review summarizes the role of ferroptosis in BBB dysfunction and the latest progress of ferroptosis mechanism, and further discusses the influence of various factors of ferroptosis on the severity and prognosis of BBB dysfunction, which may provide better therapeutic targets for BBB dysfunction.

Necroptosis-Related Modification Patterns Depict the Tumor Microenvironment, Redox Stress Landscape, and Prognosis of Ovarian Cancer

Necroptosis is one of programmed cell death discovered recently, which involves in tumorigenesis, cancer metastasis, and immune reaction. We studied the necroptosis-related genes (NRGs) in ovarian cancer (OV) tissues using data from public databases, which separated into two NRGclusters. Patients in cluster A would have severe clinical characteristics, poor prognosis, and worse tumor microenvironment infiltration characteristics. The NRG score was achieved through the Cox analysis, along with a construction of a prognostic model. People with lower risk score would have better prognosis, lower expression of redox related genes, higher immunogenicity, and better effect on immunotherapy. In addition, the NRG score was closely related to cancer stem cell index, copy number variations, tumor mutation load, and chemosensitivity. We built a nomogram to enhance clinical application of the signature. These outcomes can help use know the function of NRGs in OV and provide new ideas for evaluating clinical outcome and developing more effective treatment protocols.

Ferroptosis triggers airway inflammation in asthma

Ferroptosis is a regulatory cell death characterized by intracellular iron accumulation and lipid peroxidation that leads to oxidative stress. Many signaling pathways such as iron metabolism, lipid metabolism, and amino acid metabolism precisely regulate the process of ferroptosis. Ferroptosis is involved in a variety of lung diseases, such as acute lung injury, chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis. Increasing studies suggest that ferroptosis is involved in the development of asthma. Ferroptosis plays an important role in asthma. Iron metabolism disorders, lipid peroxidation, amino acid metabolism disorders lead to the occurrence of ferroptosis in airway epithelial cells, and then aggravate clinical symptoms in asthmatic patients. Moreover, several regulators of ferroptosis are involved in the pathogenesis of asthma, such as Nrf2, heme oxygenase-1, mevalonate pathway, and ferroptosis inhibitor protein 1. Importantly, ferroptosis inhibitors improve asthma. Thus, the pathogenesis of ferroptosis and its contribution to the pathogenesis of asthma help us better understand the occurrence and development of asthma, and provide new directions in asthma treatment. This article aimed to review the role and mechanism of ferroptosis in asthma, describing the relationship between ferroptosis and asthma based on signaling pathways and related regulatory factors. At the same time, we summarized current observations of ferroptosis in eosinophils, airway epithelial cells, and airway smooth muscle cells in asthmatic patients.

Redox-associated messenger RNAs identify novel prognostic values and influence the tumor immune microenvironment of lung adenocarcinoma

Background: An imbalance of redox homeostasis participates in tumorigenesis, proliferation, and metastasis, which results from the production of reactive oxygen species (ROS). However, the biological mechanism and prognostic significance of redox-associated messenger RNAs (ramRNAs) in lung adenocarcinoma (LUAD) still remain unclear. Methods: Transcriptional profiles and clinicopathological information were retrieved from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) of LUAD patients. A total of 31 overlapped ramRNAs were determined, and patients were separated into three subtypes by unsupervised consensus clustering. Biological functions and tumor immune-infiltrating levels were analyzed, and then, differentially expressed genes (DEGs) were identified. The TCGA cohort was divided into a training set and an internal validation set at a ratio of 6:4. Least absolute shrinkage and selection operator regression were used to compute the risk score and determine the risk cutoff in the training set. Both TCGA and GEO cohort were distinguished into a high-risk or low-risk group at the median cutoff, and then, relationships of mutation characteristics, tumor stemness, immune differences, and drug sensitivity were investigated. Results: Five optimal signatures (ANLN, HLA-DQA1, RHOV, TLR2, and TYMS) were selected. Patients in the high-risk group had poorer prognosis, higher tumor mutational burden, overexpression of PD-L1, and lower immune dysfunction and exclusion score compared with the low-risk group. Cisplatin, docetaxel, and gemcitabine had significantly lower IC₅₀ in the high-risk group. Conclusion: This study constructed a novel predictive signature of LUAD based on redox-associated genes. Risk score based on ramRNAs served as a promising biomarker for prognosis, TME, and anti-cancer therapies of LUAD.

Establishment and validation of a redox-related long non-coding RNAs prognostic signature in head and neck squamous cell carcinoma

Reduction and oxidation (redox) reactions occur in living organisms as part of normal cellular metabolism. Here, we established a novel redox-related long non-coding RNAs (rrlncRNAs) signature to predict the prognosis and therapeutic response in Head and neck squamous cell carcinoma (HNSCC). The expression profile and clinical information were obtained from the TCGA project. In total, 10 differently expressed rrlncRNAs associated with prognosis were identified and involved in a prognostic risk score signature by the least absolute shrinkage and selection operator penalized Cox analysis. The area under the receiver operating characteristic curves of the survival rates predicted by the rrlncRNAs signature over one, two, and three years were found to be 0.651, 0.670, and 0.679. Following the completion of the Kaplan-Meier survival study, we discovered that the lower-risk cohort exhibited a much longer overall survival period in contrast with the higher-risk cohort. Univariate and multivariable Cox regression analyses demonstrated that the risk score independently served as a significant predictive factor. GO annotation and KEGG pathway analyses illustrated that the rrlncRNAs signature was strongly associated with immune-related functions as well as signaling pathways. The tumor-infiltrating immune cells, tumor microenvironment, immune-related functions, HLA gene family expression, immune checkpoint genes expression, and somatic variants differed substantially between the low- and high-risk cohorts. Moreover, patients in low-risk group were predicted to present a favorable immunotherapy responsiveness, while in contrast, the high-risk group patients might have a stronger sensitivity to "docetaxel". According to our findings, the rrlncRNAs signature showed an excellent prognosis predictive value and might indicate therapeutic response to immunotherapy in HNSCC.

Scabertopin Derived from Elephantopus scaber L. Mediates Necroptosis by Inducing Reactive Oxygen Species Production in Bladder Cancer In Vitro

Bladder cancer remains one of the most common malignant tumors that threatens human health worldwide. It imposes a heavy burden on patients and society due to the high medical costs associated with its easy metastasis and recurrence. Although several treatment options for bladder cancer are available, their clinical efficacy remains unsatisfactory. Therefore, actively exploring new drugs and their mechanisms of action for the clinical treatment of bladder cancer is very important. Scabertopin is one of the major sesquiterpene lactones found in Elephantopus scaber L. Sesquiterpene lactones are thought to have fairly strong anti-cancer efficacy. However, the anticancer effect of sesquiterpenoid scabertopin on bladder cancer and its mechanism are still unclear. The aim of this study is to evaluate the antitumor activity of scabertopin in bladder cancer and its potential molecular mechanism in vitro. Our results suggest that scabertopin can induce RIP1/RIP3-dependent necroptosis in bladder cancer cells by promoting the production of mitochondrial reactive oxygen species (ROS), inhibit the expression of MMP-9 by inhibiting the FAK/PI3K/Akt signaling pathway, and ultimately inhibit the migration and invasion ability of bladder cancer cells. At the same time, we also demonstrated that the half-inhibition concentration (IC50) of scabertopin on various bladder cancer cell lines (J82, T24, RT4 and 5637) is much lower than that on human ureteral epithelial immortalized cells (SV-HUC-1). The above observations indicate that scabertopin is a potential therapeutic agent for bladder cancer that acts by inducing necroptosis and inhibiting metastasis.

Hyperbaric oxygen protects HT22 cells and PC12 cells from damage caused by oxygen-glucose deprivation/reperfusion via the inhibition of Nrf2/System Xc-/GPX4 axis-mediated ferroptosis

This study was to investigate the protective effect of hyperbaric oxygen (HBO) on HT22 and PC12 cell damage caused by oxygen-glucose deprivation/reperfusion-induced ferroptosis. A 2-h oxygen-glucose deprivation and 24-h reperfusion model on HT22 and PC12 cells was used to simulate cerebral ischemia-reperfusion injury. Cell viabilities were detected by Cell Counting Kit-8 (CCK-8) method. The levels of reactive oxygen species (ROS) and lipid reactive oxygen species (Lipid ROS) were detected by fluorescent probes Dihydroethidium (DHE) and C11 BODIPY 581/591. Iron Colorimetric Assay Kit, malondialdehyde (MDA) and glutathione (GSH) activity assay kits were used to detect intracellular iron ion, MDA and GSHcontent. Cell ferroptosis-related ultrastructures were visualized using transmission electron microscopy (TEM). Furthermore, PCR and Western blot analyses were used to detect the expressions of ferroptosis-related genes and proteins. After receiving oxygen-glucose deprivation/reperfusion, the viabilities of HT22 and PC12 cells were significantly decreased; ROS, Lipid ROS, iron ions and MDA accumulation occurred in the cells; GSH contents decreased; TEM showed that cells were ruptured and blebbed, mitochondria atrophied and became smaller, mitochondrial ridges were reduced or even disappeared, and apoptotic bodies appeared. And the expressions of Nrf2, SLC7A11 and GPX4 genes were reduced; the expressions of p-Nrf2/Nrf2, xCT and GPX4 proteins were reduced. Notably, these parameters were significantly reversed by HBO, indicating that HBO can protect HT22 cells and PC12 cells from damage caused by oxygen-glucosedeprivation/reperfusion via the inhibition of Nrf2/System Xc-/GPX4 axis-mediated ferroptosis.

Hydrogen Sulfide: A Gaseous Mediator and Its Key Role in Programmed Cell Death, Oxidative Stress, Inflammation and Pulmonary Disease

Hydrogen sulfide (H2S) has been acknowledged as a novel gaseous mediator. The metabolism of H2S in mammals is tightly controlled and is mainly achieved by many physiological reactions catalyzed by a suite of enzymes. Although the precise actions of H2S in regulating programmed cell death, oxidative stress and inflammation are yet to be fully understood, it is becoming increasingly clear that H2S is extensively involved in these crucial processes. Since programmed cell death, oxidative stress and inflammation have been demonstrated as three important mechanisms participating in the pathogenesis of various pulmonary diseases, it can be inferred that aberrant H2S metabolism also functions as a critical contributor to pulmonary diseases, which has also been extensively investigated. In the meantime, substantial attention has been paid to developing therapeutic approaches targeting H2S for pulmonary diseases. In this review, we summarize the cutting-edge knowledge on the metabolism of H2S and the relevance of H2S to programmed cell death, oxidative stress and inflammation. We also provide an update on the crucial roles played by H2S in the pathogenesis of several pulmonary diseases. Finally, we discuss the perspective on targeting H2S metabolism in the treatment of pulmonary diseases.

Ferroptosis and Its Potential Role in Glioma: From Molecular Mechanisms to Therapeutic Opportunities

Glioma is the most common intracranial malignant tumor, and the current main standard treatment option is a combination of tumor surgical resection, chemotherapy and radiotherapy. Due to the terribly poor five-year survival rate of patients with gliomas and the high recurrence rate of gliomas, some new and efficient therapeutic strategies are expected. Recently, ferroptosis, as a new form of cell death, has played a significant role in the treatment of gliomas. Specifically, studies have revealed key processes of ferroptosis, including iron overload in cells, occurrence of lipid peroxidation, inactivation of cysteine/glutathione antiporter system Xc- (xCT) and glutathione peroxidase 4 (GPX4). In the present review, we summarized the molecular mechanisms of ferroptosis and introduced the application and challenges of ferroptosis in the development and treatment of gliomas. Moreover, we highlighted the therapeutic opportunities of manipulating ferroptosis to improve glioma treatments, which may improve the clinical outcome.

Chemopreventive Effect on Human Colon Adenocarcinoma Cells of Styrylquinolines: Synthesis, Cytotoxicity, Proapoptotic Effect and Molecular Docking Analysis

Seven styrylquinolines were synthesized in this study. Two of these styrylquinolines are new and were elucidated by spectroscopic analysis. The chemopreventive potential of these compounds was evaluated against SW480 human colon adenocarcinoma cells, its metastatic derivative SW620, and normal cells (HaCaT). According to the results, compounds 3a and 3d showed antiproliferative activity in SW480 and SW620 cells, but their effect seemed to be caused by different mechanisms of action. Compound 3a induced apoptosis independent of ROS production, as evidenced by increased levels of caspase 3, and had an immunomodulatory effect, positively regulating the production of different immunological markers in malignant cell lines. In contrast, compound 3d generated a pro-oxidant response and inhibited the growth of cancer cells, probably by another type of cell death other than apoptosis. Molecular docking studies indicated that the most active compound, 3a, could efficiently bind to the proapoptotic human caspases-3 protein, a result that could provide valuable information on the biochemical mechanism for the in vitro cytotoxic response of this compound in SW620 colon carcinoma cell lines. The obtained results suggest that these compounds have chemopreventive potential against CRC, but more studies should be carried out to elucidate the molecular mechanisms of action of each of them in depth.

PM2.5 inhibits system Xc- activity to induce ferroptosis by activating the AMPK-Beclin1 pathway in acute lung injury

Urban airborne fine particulate matter (PM2.5) is a global pollution source that has been strongly related to multiple respiratory diseases involving various types of regulated cell death (RCD). However, the role of ferroptosis, a novel form of RCD, in PM2.5-induced acute lung injury (ALI), has not been elucidated. Herein, we define the role and mechanism of ferroptosis in a PM2.5-induced ALI model. First, we demonstrated that lipid peroxidation and iron accumulation were significantly enhanced in ALI models and were accompanied by activation of the AMP-activated protein kinase (AMPK)-Beclin1 signaling pathway and inhibition of the key subunit SLC7A11 of System Xc-. However, these abnormalities were partially reversed by ferroptosis inhibitors. We further revealed that Beclin1 knockdown or overexpression ameliorated or exacerbated PM2.5-induced ferroptosis, respectively. Mechanistically, we verified that Beclin1 blocks System Xc- activity to trigger ferroptosis by directly binding to SLC7A11. Finally, knockdown of Beclin1 by AAV-shRNA or inhibition of AMPK, an upstream activator of Beclin1, ameliorated PM2.5-induced ferroptosis and ALI. Taken together, our results revealed that ferroptosis plays a novel role in PM2.5-induced ALI and elucidated the specific mechanism involving the AMPK-Beclin1 pathway and System Xc-, which may provide new insight into the toxicological effects of PM2.5 on respiratory problems.

Carboxyl Group-Modified Myoglobin Induces TNF-α-Mediated Apoptosis in Leukemia Cells

Previous studies have shown that chemical modification may increase the activity of proteins or confer novel activity to proteins. Some studies have indicated that myoglobin (Mb) is cytotoxic; however, the underlying mechanisms remain unclear. In this study, we investigated whether chemical modification of the carboxyl group by semicarbazide could promote the Mb cytotoxicity in human leukemia U937 cells and the underlying mechanism of semicarbazide-modified myoglobin (SEM-Mb)-induced U937 cell death. The semicarbazide-modified Mb (SEM-Mb) induced U937 cell apoptosis via the production of cleaved caspase-8 and t-Bid, while silencing of FADD abolished this effect. These findings suggest that SEM-Mb can induce U937 cell death by activating the death receptor-mediated pathway. The SEM-Mb inhibited miR-99a expression, leading to increased NOX4 mRNA and protein expression, which promoted SIRT3 degradation, and, in turn, induced ROS-mediated p38 MAPK phosphorylation. Activated p38 MAPK stimulated miR-29a-dependent tristetraprolin (TTP) mRNA decay. Downregulation of TTP slowed TNF-α mRNA turnover, thereby increasing TNF-α protein expression. The SEM-Mb-induced decrease in cell viability and TNF-α upregulation were alleviated by abrogating the NOX4/SIRT3/ROS/p38 MAPK axis or ectopic expression of TTP. Taken together, our results demonstrated that the NOX4/SIRT3/p38 MAPK/TTP axis induces TNF-α-mediated apoptosis in U937 cells following SEM-Mb treatment. A pathway regulating p38 MAPK-mediated TNF-α expression also explains the cytotoxicity of SEM-Mb in the human leukemia cell lines HL-60, THP-1, K562, Jurkat, and ABT-199-resistant U937. Furthermore, these findings suggest that the carboxyl group-modified Mb is a potential structural template for the generation of tumoricidal proteins.

Mercuric chloride induces sequential activation of ferroptosis and necroptosis in chicken embryo kidney cells by triggering ferritinophagy

Mercuric chloride (HgCl₂) is an environmental pollutant with serious nephrotoxic effects, but the underlying mechanism of HgCl₂ nephrotoxicity is not well understood. Ferroptosis and necroptosis are two programmed cell death (PCD) modalities that have been reported singly in heavy metal-induced kidney injury. However, the interaction between ferroptosis and necroptosis in HgCl₂-induced kidney injury is unclear. Here, we established a model of HgCl₂-exposed chicken embryo kidney (CEK) cells to dissect the progresses and mechanisms of these two PCDs. We found that ferroptosis was initially activated in CEK cells after HgCl₂ exposure for 12 h, and necroptosis was activated subsequently at 24 h. Importantly, further study indicated that the shift from ferroptosis to necroptosis was driven by ROS, which was produced by iron-dependent Fenton reaction, and the iron chelation by DFO prevented the sequential activation of both ferroptosis and necroptosis. To investigate the source of intracellular iron, the regulation of iron homeostasis was first explored and demonstrated a tendency for intracellular iron overload in CEK cells. Interestingly, the cellular ferritin, a free iron depository, decreased in a time-dependent manner. Further studies revealed that the degradation of ferritin was attributed to the activation of selective cargo receptor nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy, and the inhibition of ferritinophagy by CQ prevented the HgCl₂-induced cell death. In conclusion, our study demonstrated that HgCl₂ released excess free iron via ferritinophagy, led to a sustained accumulation of ROS and ultimately activated ferroptosis and necroptosis sequentially. These findings provide a new understanding for the nephrotoxic mechanism of HgCl₂.

Epimedium koreanum Nakai-Induced Liver Injury-A Mechanistic Study Using Untargeted Metabolomics

Epimedii Folium is widely used worldwide as an herbal supplement, and the risk of its induced liver damage has emerged in recent years. Our preliminary study has found that, among several Epimedii Folium species specified in the Chinese Pharmacopoeia, Epimedium koreanum Nakai has a more severe propensity for hepatotoxicity. However, the mechanism of hepatotoxicity of Epimedium koreanum Nakai is still unclear. In this study, untargeted metabolomics was performed to analyze the serum and liver tissue to explore the mechanism of hepatotoxicity of Epimedium koreanum Nakai. The results of experiments in vivo showed that, after 28 days of exposure to Epimedium koreanum Nakai ethanol extract (EEE), the liver weight, levels of AST, ALP, TBIL, etc. in serum of rats in the EEE group were significantly increased, as well as severe cytoplasmic vacuolation appeared in the liver tissue, which suggested that EEE has significant hepatotoxicity. Subsequently, the results of metabolomics revealed significant changes in the metabolic profile in the liver and serum of rats after EEE exposure, in which metabolites in serum such as flavin mononucleotide, phenylacetylglycine, glutathione, l-tryptophan, and sphingomyelin were able to accurately identify liver injury caused by EEE and could be used as serum markers to reflect EEE-induced liver injury. The KEGG pathway enrichment analysis revealed that EEE caused extensive effects on rats' metabolic pathways. Some of the most affected pathways included glutathione metabolism, glutamate metabolism pathway, primary bile acid biosynthesis pathway, and sphingolipid metabolism pathway, which were all directed to the biological process of ferroptosis. Then, the main markers related to ferroptosis in the liver were examined, and the results demonstrated that the content of malondialdehyde was significantly increased, the activity of superoxide dismutase was significantly reduced, the ferroptosis inhibitory proteins GPX4 and System xc - were significantly downregulated, and the ferroptosis-promoting protein ACSL4 was significantly up-regulated. Judging from these results, we concluded that the mechanism of hepatotoxicity of Epimedium koreanum Nakai was probably related to the induction of ferroptosis in hepatocytes.

Polystyrene nanoplastics penetrate across the blood-brain barrier and induce activation of microglia in the brain of mice

Microplastics (MPs) have been well demonstrated as potential threats to the ecosystem, whereas the neurotoxicity of MPs in mammals remains to be elucidated. The current study was designed to investigate whether 50 nm polystyrene nanoplastics (PS-NPs) could pass through the blood-brain barrier (BBB), and to elucidate the underlying mechanisms and the following neurotoxic manifestation. In vivo study showed that PS-NPs (0.5-50 mg/kg. bw PS-NPs for 7 days) significantly induced the increase of permeability of BBB, and dose-dependently accumulated in the brain of mice. In addition, PS-NPs were found to be present in microglia, and induced microglia activation and neuron damage in the mouse brain. In vitro studies using the immortalized human cerebral microvascular endothelial cell (hCMEC/D3), the most commonly used cell model for BBB-related studies, revealed that PS-NPs could be internalized into cells, and caused reactive oxygen species (ROS) production, nuclear factor kappa-B (NF-κB) activation, tumor necrosis factors α (TNF-α) secretion, and necroptosis of hCMEC/D3 cells. Furthermore, PS-NPs exposure led to disturbance of the tight junction (TJ) formed by hCMEC/D3, as demonstrated by the decline of transendothelial electrical resistance (TEER) and decreased expression of occludin. Lastly, PS-NPs exposure resulted in the activation of murine microglia BV2 cells, and the cell medium of PS-NPs-exposed BV2 induced obvious damage to murine neuron HT-22 cells. Collectively, these results suggest that PS-NPs could pass through BBB and induce neurotoxicity in mammals probably by inducing activation of microglia.

Ferroptosis Biology and Implication in Cancers

Ferroptosis, a novel form of regulated cell death (RCD), has garnered increasing attention in studies on numerous human diseases in the last decade. Emerging evidence has indicated that the pathological process of ferroptosis involves the overloaded production of reactive oxygen species (ROS), followed by aberrant accumulation of lipid peroxidation in an iron-dependent manner, accompanied with an increased uptake of polyunsaturated fatty acids into the cellular membrane, further unfolding an ancient vulnerability in multiple context. The unique nature of ferroptosis differentiates it from other forms of RCD, as it is intricately associated with several biological processes, including the metabolism of iron, amino acids, synthesis of ROS and lipid peroxidation. Accordingly, inducers and inhibitors designed to target the key processes of ferroptosis have been extensively studied. Characterized by its distinct properties as mentioned above and its inducible nature, ferroptosis has been widely implicated in several diseases, and numerous studies have focused on identifying effective therapeutic targets for multiple human diseases, including in cancer, by targeting this process. In the present review, recent studies on the involvement of ferroptosis in several types of cancer are summarized and the findings discussed, highlighting the need for increased contemplation of its involvement in the study of cancer, particularly in the clinical setting. A comprehensive summary of the biological mechanisms underlying ferroptosis, the implications of the multiple inducers of ferroptosis, as well as immunotherapy targeting ferroptosis in different types of cancer is provided in this review to highlight the pathophysiological role of ferroptosis in carcinogenesis, to serve as an aid in future studies on the role of ferroptosis in cancer.

Heat Shock Proteins and Ferroptosis

Ferroptosis is a new form of regulatory cell death named by Dixon in 2012, which is characterized by the accumulation of lipid peroxides and iron ions. Molecular chaperones are a class of evolutionarily conserved proteins in the cytoplasm. They recognize and bind incompletely folded or assembled proteins to help them fold, transport or prevent their aggregation, but they themselves do not participate in the formation of final products. As the largest number of molecular chaperones, heat shock proteins can be divided into five families: HSP110 (HSPH), HSP90 (HSPC), HSP70 (HSPA), HSP40 (DNAJ) and small heat shock proteins (HSPB). Different heat shock proteins play different roles in promoting or inhibiting ferroptosis in different diseases. It is known that ferroptosis is participated in tumors, nervous system diseases, renal injury and ischemia-reperfusion injury. However, there are few reviews about the relationship of heat shock proteins and ferroptosis. In this study, we systematically summarize the roles of heat shock proteins in the occurrence of ferroptosis, and predict the possible mechanisms of different families of heat shock proteins in the development of ferroptosis.

SENP1 inhibition suppresses the growth of lung cancer cells through activation of A20-mediated ferroptosis

Background

Ferroptosis is a type of cell death driven by iron accumulation and lipid peroxidation, which is involved in the pathogenesis of various tumors. Small ubiquitin-like modifier (SUMO)-specific protease 1 (SENP1) is a critical SUMO-specific protease, which controls multiple cellular signaling processes. However, the roles and mechanisms of SENP1-mediated protein SUMOylation in the regulation of cell death and ferroptosis remain unexplored.

Methods

The gene expression of SENP1 and ferroptosis-related genes in samples of lung cancer patient and cells were determined by immunohistochemical staining, real-time polymerase chain reaction (RT-qPCR) and Western blot. The association of gene expression with the survival rate of lung cancer patients was analyzed from public database. The erastin and cisplatin was used to induce ferroptosis, and cell ferroptosis were determined by evaluated lipid-reactive oxygen species (ROS), cell viability and electron microscopy. The protein interaction was determined by immunoprecipitation (IP) and shotgun proteomics analysis. An in vivo tumor transplantation model of immunodeficient mice was used to evaluate the effect of SENP1 on tumor growth in vivo.

Results

SENP1 is aberrantly overexpressed in lung cancer cells and is associated with the low survival rate of patients. SENP1 inhibition by short hairpin RNA transduction or a specific inhibitor suppressed the proliferation and growth of lung cancer cells both in vitro and in vivo. SENP1 overexpression protected lung cancer cells from ferroptosis induced by erastin or cisplatin. Transcriptome and proteomics profiles revealed the involvement of SUMOylation regulation of the inflammation signal A20 in SENP1 inhibition-induced ferroptosis. Functional studies proved that A20 functions as a positive inducer and enhances the ferroptosis of A549 cells. A20 was shown to interact with ACSL4 and SLC7A11 to regulate the ferroptosis of lung cancer cells.

Conclusions

SENP1 was identified as a suppressor of ferroptosis through a novel network of A20 SUMOylation links ACSL4 and SLC7A11 in lung cancer cells. SENP1 inhibition promotes ferroptosis and apoptosis and represents a novel therapeutic target for lung cancer therapy.

m6A: An Emerging Role in Programmed Cell Death

Programmed cell death is an active extinction process, including autophagy, ferroptosis, pyroptosis, apoptosis, and necroptosis. m6A is a reversible RNA modification which undergoes methylation under the action of methylases (writers), and is demethylated under the action of demethylases (erasers). The RNA base site at which m6A is modified is recognized by specialized enzymes (readers) which regulate downstream RNA translation, decay, and stability. m6A affects many aspects of mRNA metabolism, and also plays an important role in promoting the maturation of miRNA, the translation and degradation of circRNA, and the stability of lncRNA. The regulatory factors including writers, erasers and readers promote or inhibit programmed cell death via up-regulating or down-regulating downstream targets in a m6A-dependent manner to participate in the process of disease. In this review, we summarize the functions of m6A with particular reference to its role in programmed cell death.

Preparation of nanoscale cationic metal–organic framework Nano Mn(iii)-TP for theranostics based on valence changes

Schematic illustrations of the synthesis and working principle of a platform MTXNa@Nano Mn(iii)-TP for tumor theranostics.

Research progress on the mechanism of ferroptosis and its clinical application

Ferroptosis is a mode of cell death dependent on iron ions, which is mainly induced by the decrease of the biological activity of glutathione peroxidase or the accumulation of lipid peroxidation and reactive oxygen species (ROS). It is significantly different from autophagy and other forms of cell death in terms of cell morphology and biochemistry. The exact mechanisms of ferroptosis are not clear. More and more studies have shown that various tumor diseases and nervous system diseases are closely related to ferroptosis. The occurrence and development of related diseases can be tolerated by stimulating or inhibiting the occurrence of ferroptosis. Therefore, ferroptosis has occupied a very important position in recent years. This article reviews the discovery process, characteristics, mechanisms, inducers, inhibitors of ferroptosis and its related clinical applications to lay a foundation for follow-up researchers to study ferroptosis and provide some reference value.

The role of reactive oxygen species in the immunity induced by nano-pulse stimulation

Reactive oxygen species (ROS) are byproducts of tumor cells treated with Nano-Pulse Stimulation (NPS). Recently, ROS have been suggested as a contributing factor in immunogenic cell death and T cell-mediated immunity. This research further investigated the role of NPS induced ROS in antitumor immunity. ROS production in 4T1-luc breast cancer cells was characterized using three detection reagents, namely, Amplex Red, MitoSox Red, and Dihydroethidium. The efficiency of ROS quenching was evaluated in the presence or absence of ROS scavengers and/or antioxidants. The immunogenicity of NPS treated tumor cells was assessed by ex vivo dendritic cell activation, in vivo vaccination assay and in situ vaccination with NPS tumor ablation. We found that NPS treatment enhanced the immunogenicity of 4T1-luc mouse mammary tumor, resulted in a potent in situ vaccination protection and induced long-term T cell immunity. ROS production derived from NPS treated breast cancer cells was an electric pulse dose-dependent phenomenon. Noticeably, the dynamic pattern of hydrogen peroxide production was different from that of superoxide production. Interestingly, regardless of NPS treatment, different ROS scavengers could either block or promote ROS production and stimulate or inhibit tumor cell growth. The activation of dendritic cells was not influenced by blocking ROS generation. The results from in vivo vaccination with NPS treated cancer cells suggests that ROS generation was not a prerequisite for immune protection.

Dichloroacetate enhances the anti-tumor effect of sorafenib via modulating the ROS-JNK-Mcl-1 pathway in liver cancer cells

Liver cancer is one of the most common and high recurrence malignancies. Besides radiotherapy and surgery, chemotherapy also plays an essential role in the treatment of liver cancer. Sorafenib and sorafenib-based combination therapies have been proven efficacy against tumors. However, previous clinical studies have indicated that some patients with liver cancer are resistant to sorafenib treatment and the existing strategies are not satisfactory in the clinic. Therefore, it is urgent to investigate strategies to improve the effectiveness of sorafenib for liver cancer and to explore effective drug combinations. In the present study, we found that dichloroacetate (DCA) could significantly enhance the anti-tumor effect of sorafenib on liver cancer cells, including reduced viability and dramatically promoted apoptosis in liver cancer cells. Moreover, compared to sorafenib alone, the combination of DCA and sorafenib markedly increased the degradation of anti-apoptotic protein Mcl-1 by enhancing its phosphorylation. Overexpression of Mcl-1 could significantly attenuate the synergetic effect of DCA and sorafenib on apoptosis induction in liver cancer cells. Furthermore, we found that the ROS-JNK pathway was obviously activated in the DCA combined sorafenib group. The levels of ROS and p-JNK were dramatically up-regulated in the two drug combination groups. Antioxidant NAC could alleviate the synergetic effects of DCA and sorafenib on ROS generation, JNK activation, Mcl-1 degradation, and cell apoptosis. Moreover, DCA and sorafenib's effects on Mcl-1 degradation and apoptosis could also be inhibited by JNK inhibitor 'SP'600125. Finally, the synergetic effects of DCA and sorafenib on tumor growth suppression, Mcl-1 degradation and induction of apoptosis were also validated in liver cancer xenograft in vivo. These findings indicate that DCA enhances the anti-tumor effect of sorafenib via the ROS-JNK-Mcl-1 pathway in liver cancer cells. This study may provide new insights to improve the chemotherapeutic effect of sorafenib, which may be beneficial for further clinical application of sorafenib in liver cancer treatment.

Vitamin E Can Ameliorate Oxidative Damage of Ovine Hepatocytes In Vitro by Regulating Genes Expression Associated with Apoptosis and Pyroptosis, but Not Ferroptosis

(1) Background: the current research was conducted to investigate the potential non-antioxidant roles of vitamin E in the protection of hepatocysts from oxidative damage. (2) Methods: primary sheep hepatocytes were cultured and exposed to 200, 400, 600, or 800 μmol/L hydrogen peroxide, while their viability was assessed using a CCK-8 kit. Then, cells were treated with 400 μmol/L hydrogen peroxide following a pretreatment with 50, 100, 200, 400, and 800 μmol/L vitamin E and their intracellular ROS levels were determined by means of the DCF-DA assay. RNA-seq, verified by qRT-PCR, was conducted thereafter: non-treated control (C1); cells treated with 400 μmol/L hydrogen peroxide (C2); and C2 plus a pretreatment with 100 μmol/L vitamin E (T1). (3) Results: the 200-800 μmol/L hydrogen peroxide caused significant cell death, while 50, 100, and 200 μmol/L vitamin E pretreatment significantly improved the survival rate of hepatocytes. ROS content in the cells pretreated with vitamin E was significantly lower than that in the control group and hydrogen-peroxide-treated group, especially in those pretreated with 100 μmol/L vitamin E. The differentially expressed genes (DEGs) concerning cell death involved in apoptosis (RIPK1, TLR7, CASP8, and CASP8AP2), pyroptosis (NLRP3, IL-1β, and IRAK2), and ferroptosis (TFRC and PTGS2). The abundances of IL-1β, IRAK2, NLRP3, CASP8, CASP8AP2, RIPK1, and TLR7 were significantly increased in the C1 group and decreased in T1 group, while TFRC and PTGS2 were increased in T1 group. (4) Conclusions: oxidative stress induced by hydrogen peroxide caused cellular damage and death in sheep hepatocytes. Pretreatment with vitamin E effectively reduced intracellular ROS levels and protected the hepatocytes from cell death by regulating gene expression associated with apoptosis (RIPK1, TLR7, CASP8, and CASP8AP2) and pyroptosis (NLRP3, IL-1β, and IRAK2), but not ferroptosis (TFRC and PTGS2).

The potential application of nanomaterials for ferroptosis-based cancer therapy

Ferroptosis is a new type of programmed cell death, which is expected to become an important strategy of cancer treatment. Traditional strategies for inducing iron death are small molecule inducers based on biological agents. However, because of their poor water solubility, low cell targeting ability and fast metabolismin vivo, it is difficult for molecular drugs to play the long-acting role of ferroptosis induction. With the further study of ferroptosis and development of nanotechnology, nanomaterials have been proved to be more efficient drugs for inducing ferroptosis than those biological drugs. Therein, iron-based nanomaterials can directly release high concentrations of irons and increase reactive oxygen species levels in cells, which produce a better induction effect for ferroptosis. Whereas, it is challenging to differentiate nanoparticle-induced ferroptosis and traditional inducing strategies, elucidate the detailed mechanisms and further classify the synthetical methods of nanomaterials. For better guidance on the development of anticancer strategies, comprehensive summary of the latest developments of ferroptosis related nanomaterials, especially iron-based nanomaterials are in urgent need. In the paper, we summarized the main mechanisms of ferroptosis, highlighted the latest developments of nanomaterials for ferroptosis, and emphasized the advantages of iron-based nanomaterials for ferroptosis. The future prospect in this field was also discussed, paving the way for the related nanomaterials in the clinical cancer therapy.