STYK1/NOK correlates with ferroptosis in non-small cell lung carcinoma

Genetic profile of ferroptosis in non-small cell lung carcinoma and pharmaceutical options for ferroptosis induction

Lung cancer (LC) is the leading cause of cancer-related deaths and the second most commonly diagnosed malignancy worldwide. Lung adenocarcinoma (LUAD) and lung squamous cell LC (LUSCC) are the most common subtypes of non-small cell LC (NSCLC). Early diagnosis of LC can be challenging due to a lack of biomarkers. The overall survival (OS) of patients with NSCLC is still poor despite the enormous efforts that have been made to develop novel treatments. Understanding fundamental molecular and genetic mechanisms is necessary to develop new therapeutic approaches for NSCLC. A recently identified type of programmed cell death known as ferroptosis is one potential approach. Ferroptosis causes oxidative damage and the death of cancerous cells by peroxidizing unsaturated phospholipids and accumulating reactive oxygen species (ROS) in an iron-dependent manner. Ferroptosis-related gene (FRG) signatures have recently been evaluated for their ability to predict patient OS and prognosis. These analyses show FRGs are involved in cancer progression, and may serve as promising biomarkers for tumor diagnosis and therapy. Moreover, we summarize the current pharmaceutical options of ferroptosis induction and their underlying molecular mechanism in LC. Therefore, this review aims to provide a comprehensive summary of FRG-based prognostic models, their associated metabolic and signaling pathways, and promising therapeutic options for ferroptosis induction in NSCLC.

Targeting ferroptosis using Chinese herbal compounds to treat respiratory diseases

BACKGROUND

Respiratory diseases pose a grave threat to human life. Therefore, understanding their pathogenesis and therapeutic strategy is important. Ferroptosis is a novel type of iron-dependent programmed cell death, distinct from apoptosis, necroptosis, and autophagy, characterised by iron, reactive oxygen species, and lipid peroxide accumulation, as well as glutathione (GSH) depletion and GSH peroxidase 4 (GPX4) inactivation. A close association between ferroptosis and the onset and progression of respiratory diseases, including chronic obstructive pulmonary disease, acute lung injury, bronchial asthma, pulmonary fibrosis, and lung cancer, has been reported. Recent studies have shown that traditional Chinese medicine (TCM) compounds exhibit unique advantages in the treatment of respiratory diseases owing to their natural properties and potential efficacy. These compounds can effectively regulate ferroptosis by modulating several key signalling pathways such as system Xc- -GSH-GPX4, NCOA4-mediated ferritinophagy, Nrf2-GPX4, and Nrf2/HO-1, thus playing a positive role in improving respiratory diseases.

PURPOSE

This comprehensive review systematically outlines the regulatory role of ferroptosis in the onset and progression of respiratory diseases and provides evidence for treating respiratory diseases by targeting ferroptosis with TCM compounds. These insights aim to offer potential remedies for the clinical prevention and treatment of respiratory diseases.

STUDY DESIGN AND METHODS

We searched scientific databases PubMed, Web of Science, Scopus, and CNKI using keywords such as "ferroptosis","respiratory diseases","chronic obstructive pulmonary disease","bronchial asthma","acute lung injury","pulmonary fibrosis","lung cancer","traditional Chinese medicine","traditional Chinese medicine compound","monomer", and "natural product" to retrieve studies on the therapeutic potential of TCM compounds in ameliorating respiratory diseases by targeting ferroptosis. The retrieved data followed PRISMA criteria (preferred reporting items for systematic review).

RESULTS

TCM compounds possess unique advantages in treating respiratory diseases, stemming from their natural origins and proven clinical effectiveness. TCM compounds can exert therapeutic effects on respiratory diseases by regulating ferroptosis, which mainly involves modulation of pathways such as system Xc- -GSH-GPX4,NCOA4-mediated ferritinophagy, Nrf2-GPX4, and Nrf2/HO-1.

CONCLUSION

TCM compounds have demonstrated promising potential in improving respiratory diseases through the regulation of ferroptosis. The identification of specific TCM-related inducers and inhibitors of ferroptosis holds great significance in developing more effective strategies. However, current research remains confined to animal and cellular studies, emphasizing the imperative for further verifications through high-quality clinical data.

The new era of lung cancer therapy: Combining immunotherapy with ferroptosis

Ferroptosis is an unconventional programmed cell death mode caused by phospholipid peroxidation dependent on iron. Emerging immunotherapies (especially immune checkpoint inhibitors) have the potential to enhance lung cancer patients' long-term survival. Although immunotherapy has yielded significant positive applications in some patients, there are still many mechanisms that can cause lung cancer cells to evade immunity, thus leading to the failure of targeted therapies. Immune-tolerant cancer cells are insensitive to conventional death pathways such as apoptosis and necrosis, whereas mesenchymal and metastasis-prone cancer cells are particularly vulnerable to ferroptosis, which plays a vital role in mediating immune tolerance resistance by tumors and immune cells. As a result, triggering lung cancer cell ferroptosis holds significant therapeutic potential for drug-resistant malignancies. Here, we summarize the mechanisms underlying the suppression of ferroptosis in lung cancer, highlight its function in the lung cancer immune microenvironment, and propose possible therapeutic strategies.

Induction of ferroptosis by natural products in non-small cell lung cancer: a comprehensive systematic review

Lung cancer is one of the leading causes of cancer-related deaths worldwide that presents a substantial peril to human health. Non-Small Cell Lung Cancer (NSCLC) is a main subtype of lung cancer with heightened metastasis and invasion ability. The predominant treatment approaches currently comprise surgical interventions, chemotherapy regimens, and radiotherapeutic procedures. However, it poses significant clinical challenges due to its tumor heterogeneity and drug resistance, resulting in diminished patient survival rates. Therefore, the development of novel treatment strategies for NSCLC is necessary. Ferroptosis was characterized by iron-dependent lipid peroxidation and the accumulation of lipid reactive oxygen species (ROS), leading to oxidative damage of cells and eventually cell death. An increasing number of studies have found that exploiting the induction of ferroptosis may be a potential therapeutic approach in NSCLC. Recent investigations have underscored the remarkable potential of natural products in the cancer treatment, owing to their potent activity and high safety profiles. Notably, accumulating evidences have shown that targeting ferroptosis through natural compounds as a novel strategy for combating NSCLC holds considerable promise. Nevertheless, the existing literature on comprehensive reviews elucidating the role of natural products inducing the ferroptosis for NSCLC therapy remains relatively sparse. In order to furnish a valuable reference and support for the identification of natural products inducing ferroptosis in anti-NSCLC therapeutics, this article provided a comprehensive review explaining the mechanisms by which natural products selectively target ferroptosis and modulate the pathogenesis of NSCLC.

Emerging mechanisms of ferroptosis and its implications in lung cancer

ABSTRACT

Lung cancer is one of the most common malignancies and has the highest number of deaths among all cancers. Despite continuous advances in medical strategies, the overall survival of lung cancer patients is still low, probably due to disease progression or drug resistance. Ferroptosis is an iron-dependent form of regulated cell death triggered by the lethal accumulation of lipid peroxides, and its dysregulation is implicated in cancer development. Preclinical evidence has shown that targeting the ferroptosis pathway could be a potential strategy for improving lung cancer treatment outcomes. In this review, we summarize the underlying mechanisms and regulatory networks of ferroptosis in lung cancer and highlight ferroptosis-targeting preclinical attempts to provide new insights for lung cancer treatment.

Ferroptosis in lung cancer: dual role, multi-level regulation, and new therapeutic strategies

Lung cancer is a highly prevalent malignant tumor worldwide, with high incidence and death rates. Recently, there has been increasing recognition of the role of ferroptosis, a unique cell death mechanism, in lung cancer. This review aims to summarize the current research progress on the relationship between ferroptosis and lung cancer. It also provides a comprehensive analysis of the regulatory processes of ferroptosis in various stages, including epigenetics, transcription, post-transcription, translation, and post-translation. Additionally, the review explores the dual nature of ferroptosis in lung cancer progression, which presents interesting therapeutic possibilities. On one hand, ferroptosis can promote the escape of immune surveillance and reduce the efficacy of treatment in the early stages of tumors. On the other hand, it can counter drug resistance, enhance radiosensitivity, and promote immunotherapy. The article also discusses various combination treatment strategies based on the mechanism of ferroptosis. Overall, this review offers a holistic perspective on the role of ferroptosis in the onset, progression, and treatment of lung cancer. It aims to contribute to future research and clinical interventions in this field.

GelMA/PEDOT:PSS Composite Conductive Hydrogel-Based Generation and Protection of Cochlear Hair Cells through Multiple Signaling Pathways

Recent advances in cochlear implantology are exemplified by novel functional strategies such as bimodal electroacoustic stimulation, in which the patient has intact low-frequency hearing and profound high-frequency hearing pre-operatively. Therefore, the synergistic restoration of dysfunctional cochlear hair cells and the protection of hair cells from ototoxic insults have become a persistent target pursued for this hybrid system. In this study, we developed a composite GelMA/PEDOT:PSS conductive hydrogel that is suitable as a coating for the cochlear implant electrode for the potential local delivery of otoregenerative and otoprotective drugs. Various material characterization methods (e.g., 1H NMR spectroscopy, FT-IR, EIS, and SEM), experimental models (e.g., murine cochlear organoid and aminoglycoside-induced ototoxic HEI-OC1 cellular model), and biological analyses (e.g., confocal laser scanning microscopy, real time qPCR, flow cytometry, and bioinformatic sequencing) were used. The results demonstrated decent material properties of the hydrogel, such as mechanical (e.g., high tensile stress and Young's modulus), electrochemical (e.g., low impedance and high conductivity), biocompatibility (e.g., satisfactory cochlear cell interaction and free of systemic toxicity), and biosafety (e.g., minimal hemolysis and cell death) features. In addition, the CDR medicinal cocktail sustainably released by the hydrogel not only promoted the expansion of the cochlear stem cells but also boosted the trans-differentiation from cochlear supporting cells into hair cells. Furthermore, hydrogel-based drug delivery protected the hair cells from oxidative stress and various forms of programmed cell death (e.g., apoptosis and ferroptosis). Finally, using large-scale sequencing, we enriched a complex network of signaling pathways that are potentially downstream to various metabolic processes and abundant metabolites. In conclusion, we present a conductive hydrogel-based local delivery of bifunctional drug cocktails, thereby serving as a potential solution to intracochlear therapy of bimodal auditory rehabilitation and diseases beyond.

Emerging roles and therapeutic potentials of ferroptosis: from the perspective of 11 human body organ systems

Since ferroptosis was first described as an iron-dependent cell death pattern in 2012, there has been increasing interest in ferroptosis research. In view of the immense potential of ferroptosis in treatment efficacy and its rapid development in recent years, it is essential to track and summarize the latest research in this field. However, few writers have been able to draw on any systematic investigation into this field based on human body organ systems. Hence, in this review, we provide a comprehensive description of the latest progress in unveiling the roles and functions, as well as the therapeutic potential of ferroptosis, in treating diseases from the aspects of 11 human body organ systems (including the nervous system, respiratory system, digestive system, urinary system, reproductive system, integumentary system, skeletal system, immune system, cardiovascular system, muscular system, and endocrine system) in the hope of providing references for further understanding the pathogenesis of related diseases and bringing an innovative train of thought for reformative clinical treatment.

Leveraging a disulfidptosis/ferroptosis-based signature to predict the prognosis of lung adenocarcinoma

BACKGROUND

Disulfidptosis and Ferroptosis are two novel forms of cell death. Although their mechanisms differ, research has shown that there is a relationship between the two. Investigating the connection between these two forms of cell death can further deepen our understanding of the development and progression of cancer, and provide better prediction models for accurate prognosis.

METHODS

In this study, RNA sequencing (RNA-seq) data, clinical data, single nucleotide polymorphism (SNP) data, and single-cell sequencing data were obtained from public databases. We used weighted gene co-expression network analysis (WGCNA) and unsupervised clustering to identify new Disulfidptosis/Ferroptosis-Related Genes (DFRG), and constructed a LASSO COX prognosis model that was externally validated. To further explore this novel signature, pathway and function analysis was performed, and differences in gene mutation frequency between high- and low-risk groups were studied. Importantly, we also conducted research on immune checkpoint, immune cell infiltration levels and immune resistance indicators, in addition to analyzing real clinical immunotherapy data.

RESULTS

We have identified four optimal disulfidptosis/ferroptosis-related genes (ODFRGs) that are differentially expressed and associated with the prognosis of Lung Adenocarcinoma (LUAD). These genes include GMPR, MCFD2, MRPL13, and SALL2. Based on these ODFRGs, we constructed a robust prognostic model in this study, and the high-risk group showed significantly lower overall survival (OS) compared to the low-risk group. Furthermore, this model can also predict the immunotherapy outcomes of LUAD patients to some extent.

Ferroptosis in lung cancer: a novel pathway regulating cell death and a promising target for drug therapy

Lung cancer is a common malignant tumor that occurs in the human body and poses a serious threat to human health and quality of life. The existing treatment methods mainly include surgical treatment, chemotherapy, and radiotherapy. However, due to the strong metastatic characteristics of lung cancer and the emergence of related drug resistance and radiation resistance, the overall survival rate of lung cancer patients is not ideal. There is an urgent need to develop new treatment strategies or new effective drugs to treat lung cancer. Ferroptosis, a novel type of programmed cell death, is different from the traditional cell death pathways such as apoptosis, necrosis, pyroptosis and so on. It is caused by the increase of iron-dependent reactive oxygen species due to intracellular iron overload, which leads to the accumulation of lipid peroxides, thus inducing cell membrane oxidative damage, affecting the normal life process of cells, and finally promoting the process of ferroptosis. The regulation of ferroptosis is closely related to the normal physiological process of cells, and it involves iron metabolism, lipid metabolism, and the balance between oxygen-free radical reaction and lipid peroxidation. A large number of studies have confirmed that ferroptosis is a result of the combined action of the cellular oxidation/antioxidant system and cell membrane damage/repair, which has great potential application in tumor therapy. Therefore, this review aims to explore potential therapeutic targets for ferroptosis in lung cancer by clarifying the regulatory pathway of ferroptosis. Based on the study of ferroptosis, the regulation mechanism of ferroptosis in lung cancer was understood and the existing chemical drugs and natural compounds targeting ferroptosis in lung cancer were summarized, with the aim of providing new ideas for the treatment of lung cancer. In addition, it also provides the basis for the discovery and clinical application of chemical drugs and natural compounds targeting ferroptosis to effectively treat lung cancer.

Ferroptosis-Related Gene GCLC Is a Novel Prognostic Molecular and Correlates with Immune Infiltrates in Lung Adenocarcinoma

Ferroptosis, a newly discovered iron-dependent type of cell death, has been found to play a crucial role in the depression of tumorigenesis. However, the prognostic value of ferroptosis-related genes (FRGs) in lung adenocarcinoma (LUAD) remains to be further elucidated. Differential expression analysis and univariate Cox regression analysis were utilized in this study to search for FRGs that were associated with the prognosis of LUAD patients. The influences of candidate markers on LUAD cell proliferation, migration, and ferroptosis were evaluated by CCK8, colony formation, and functional experimental assays in association with ferroptosis. To predict the prognosis of LUAD patients, we constructed a predictive signature comprised of six FRGs. We discovered a critical gene (GCLC) after intersecting the prognostic analysis results of all aspects, and its high expression was associated with a bad prognosis in LUAD. Correlation research revealed that GCLC was related to a variety of clinical information from LUAD patients. At the same time, in the experimental verification, we found that GCLC expression was upregulated in LUAD cell lines, and silencing GCLC accelerated ferroptosis and decreased LUAD cell proliferation and invasion. Taken together, this study established a novel ferroptosis-related gene signature and discovered a crucial gene, GCLC, that might be a new prognostic biomarker of LUAD patients, as well as provide a potential therapeutic target for LUAD patients.

System Xc−/GSH/GPX4 axis: An important antioxidant system for the ferroptosis in drug-resistant solid tumor therapy

The activation of ferroptosis is a new effective way to treat drug-resistant solid tumors. Ferroptosis is an iron-mediated form of cell death caused by the accumulation of lipid peroxides. The intracellular imbalance between oxidant and antioxidant due to the abnormal expression of multiple redox active enzymes will promote the produce of reactive oxygen species (ROS). So far, a few pathways and regulators have been discovered to regulate ferroptosis. In particular, the cystine/glutamate antiporter (System Xc−), glutathione peroxidase 4 (GPX4) and glutathione (GSH) (System Xc−/GSH/GPX4 axis) plays a key role in preventing lipid peroxidation-mediated ferroptosis, because of which could be inhibited by blocking System Xc−/GSH/GPX4 axis. This review aims to present the current understanding of the mechanism of ferroptosis based on the System Xc−/GSH/GPX4 axis in the treatment of drug-resistant solid tumors.

Clinical and Biological Significances of a Ferroptosis-Related Gene Signature in Lung Cancer Based on Deep Learning

Acyl-CoA synthetase long-chain family member 4 (ACSL4) has been linked to the occurrence of tumors and is implicated in the ferroptosis process. Deep learning has been applied to many areas in health care, including imaging diagnosis, digital pathology, classification of cancer, and prediction of metastasis. Nonetheless, neither the level of ACSL4 expression nor its predictive significance in non-small-cell lung cancer (NSCLC) is well understood at this time. Predictions of the ACSL4 mRNA expressions in NSCLC and its link to NSCLC prognosis were made with the aid of the Oncomine and TCGA databases. By performing real-time PCR, we detected the levels of ACSL4 expression that were present in human NSCLC samples. Analyses of the diagnostic, as well as the prognostic significance of ACSL4 in NSCLC, were performed with the use of Kaplan-Meier curves. To assess the influence of ACSL4 on ferroptosis in NSCLC cell lines, an inducer of ferroptosis, namely, erastin, was utilized in this study. In NSCLC tissues, there was a substantial decrease in the level of ACSL4 expression (p < 0.001), and this was in line with the findings of the inquiry into the Oncomine and TCGA databases. After that, the findings of the immunohistochemistry analysis revealed that the ACSL4 staining was weakened in NSCLC samples in contrast with the normal samples. It was shown that the differential expression of ACSL4 was substantially linked to the stages of cancer, smoking behaviors, and the status of nodal metastases (all p < 0.001). According to the findings of the survival analysis, both RFS and OS were favorable among NSCLC patients who had elevated expression of ACSL4. The ferroptosis sensitization in cancer cells may be reestablished with upregulation of ACSL4 through gene transfection. Mechanistically, protein ubiquitination could perform a remarkable function in ACSL4-induced ferroptosis. ACSL4, which has a function in ferroptosis as both a contributor and monitor, was shown to be downregulated in NSCLC. This finding suggests that ACSL4 might function as a helpful diagnostic and prognostic biological marker and might also be considered a novel possible treatment target for NSCLC.

Capsaicin induces ferroptosis of NSCLC by regulating SLC7A11/GPX4 signaling in vitro

NSCLC is the first cause of cancer-related deaths in China and threatens life expectancy of the people. Novel drugs and treatment strategies are urgently required. Capsaicin is noticed as a potential new drug for lots of tumors due to its anti-proliferative effect on cancer cells. Our study evaluated the roles of capsaicin in NSCLC cells (A549 and NCI-H23) and further explored its underlying mechanisms. Effect of capsaicin treatment on cell viability was determined by MTT assay and IC50 values for A549 and NCI-H23 cells were ascertained. The iron kit detected the total iron levels and the ferric divalent ions levels in A549 and NCI-H23 cells. GSH kit was used to detect the expression of GSH in A549 and NCI-H23 cells. Additionally, mRNA and protein levels of SLC7A11 and GPX4 were analyzed by real-time PCR and western blot analysis. Through MTT assay, we found that 200 μM capsaicin in cultured A549 cells for 48 h could reach the IC50 value, and the condition was 100 μM and 48 h for NCI-H23 cells. Capsaicin increased total iron levels and ferrous ion levels in A549 and NCI-H23 cells in contrast with the control group, whereas the levels of GSH was reduced in contrast with the control group. Besides, mRNA and protein levels of SLC7A11 and GPX4 were decreased significantly in A549 and NCI-H23 cells treated with capsaicin in contrast with the control group. Our study indicated that capsaicin inhibited the proliferation of A549 and NCI-H23 cells and induced ferroptosis by inactivating SLC7A11/GPX4 signaling. Capsaicin could be used as a potential anticancer agent in the treatment of NSCLC.

Screening for Potential Therapeutic Agents for Non-Small Cell Lung Cancer by Targeting Ferroptosis

Ferroptosis is a form of non-apoptotic and iron-dependent cell death originally identified in cancer cells. Recently, emerging evidence showed that ferroptosis-targeting therapy could be a novel promising anti-tumour treatment. However, systematic analyses of ferroptosis-related genes for the prognosis of non-small cell lung cancer (NSCLC) and the development of antitumor drugs exploiting the ferroptosis process remain rare. This study aimed to identify genes related to ferroptosis and NSCLC and to initially screen lead compounds that induce ferroptosis in tumor cells. We downloaded mRNA expression profiles and NSCLC clinical data from The Cancer Genome Atlas database to explore the prognostic role of ferroptosis-related genes. Four prognosis-associated ferroptosis-related genes were screened using univariate Cox regression analysis and the lasso Cox regression analysis, which could divide patients with NSCLC into high- and low-risk groups. Then, based on differentially expressed risk- and ferroptosis-related genes, the negatively correlated lead compound flufenamic acid (FFA) was screened through the Connective Map database. This project confirmed that FFA induced ferroptosis in A549 cells and inhibited growth and migration in a dose-dependent manner through CCK-8, scratch, and immunofluorescence assays. In conclusion, targeting ferroptosis might be a therapeutic alternative for NSCLC.

Induction of Ferroptosis by Ophiopogonin-B Through Regulating the Gene Signature AURKA in NSCLC

Ferroptosis is a new type of iron-dependent programmed cell death. In recent years, its role in the diagnosis and treatment of multiple tumors, including non-small cell lung cancer (NSCLC), has been continuously observed. The relationship between the ferroptosis-related genes and the prognosis of patients with NSCLC needs to be clarified. In this study, The Cancer Genome Atlas (TCGA) and the Gene Expression Synthesis database (Gene Expression Omnibus, GEO) were used to build a model of ferroptosis-related differentially expressed genes (DEGs). A total of 101 ferroptosis-related DEGs were screened using R language, and a 12-gene signature was finally established through univariate Cox regression analysis and least absolute shrinkage and selection operator (LASSO)-penalized Cox regression analysis. According to the risk scores, the patients were divided into a high-risk or a low-risk group, with patients in the low-risk group showing better prognosis. AURKA, one of the genes in the 12-gene signature, was found to be highly expressed in tumors. In addition, further study verified AURKA to be a negative regulator of ferroptosis in NSCLC cells. Ophiopogonin B (OP-B) had been reported to induce apoptosis, mitotic catastrophe, and autophagy in NSCLC cells. Herein, proteomic sequencing analysis and OP-B administration revealed the upregulation of AURKA and the downregulation of PHKG2 and SLC7A5 in the 12-gene signature, indicating that OP-B induced ferroptosis in NSCLC. Determination of the concentrations of malondialdehyde (MDA), glutathione (GSH), and intracellular iron and the mitochondrial membrane potential (MMP) confirmed the induction of ferroptosis by OP-B in vitro. Furthermore, transmission electron microscopy (TEM) examination of lung cancer xenotransplantation in nude mice confirmed that OP-B induced ferroptosis in vivo. Further study of the molecular mechanism showed that the ferroptosis effect caused by OP-B can be partially reversed by the overexpression of AURKA. Overall, our study established a new ferroptosis-related risk prediction model for the prognosis of patients with NSCLC, revealed the enrichment pathways of ferroptosis in NSCLC, and discovered the negative regulation of AURKA in ferroptosis. On this basis, we demonstrated that OP-B can induce ferroptosis in NSCLC and clarified the specific molecular mechanism of OP-B inducing ferroptosis by regulating the expression of AURKA.

Expression of ferroptosis-related gene correlates with immune microenvironment and predicts prognosis in gastric cancer

The study is to explore the role of ferroptosis-related genes (FRGs) in the occurrence and development of gastric cancer (GC), and to construct a new prognosis signature to predict the prognosis in GC. Clinical information and corresponding RNA data of GC patients were downloaded from TCGA and GEO databases. Consensus clustering was performed to identify new molecular subgroups. ESTIMATE, CIBERSORT, McpCounter and TIMER algorithm were used to analyze the infiltration of immune cells in two molecular subgroups. LASSO algorithm and multivariate Cox analysis were used to construct a prognostic risk signature. Functional analysis was conducted to elucidate the underlying mechanisms. Finally, the FRPGs were verified by Quantitative Real-Time PCR. We obtained 16 FRGs and divided GC patients into two subgroups by consistent clustering. Cluster C1 with a higher abundance of immune cell infiltration but lower probability in response to immunotherapy, it was reasonable to speculate that Cluster C1 was in accordance with the immune rejection type. Functional analysis showed that the biological process of DEGs in training cohort mainly included immune globulin, and human immune response mediated by circulating immune globulin. GSEA analysis showed that compared with Cluster C2, Cluster C1 showed lower expression in lipid metabolism. The nomogram combined with risk signature and clinical features can accurately predict the prognosis of GC patients. We identified two molecular subtypes, Clusters C1 and C2. In Cluster C1, patients with poor prognosis present with a hyperimmune status and low lipid metabolism, and we speculate that Cluster C1 was in accordance with the immune rejection type. The risk model based on FRPGs can accurately predict the prognosis of GC. These results indicated that ferroptosis is associated with TIME, and deserved considerable attention in determining immunotherapy treatment strategy for GC patients.

Function and regulation of GPX4 in the development and progression of fibrotic disease

Fibrosis is a common feature of fibrotic diseases that poses a serious threat to global health due to high morbidity and mortality in developing countries. There exist some chemical compounds and biomolecules associated with the development of fibrosis, including cytokines, hormones, and enzymes. Among them, glutathione peroxidase 4 (GPX4), as a selenoprotein antioxidant enzyme, is widely found in the embryo, testis, brain, liver, heart, and photoreceptor cells. Moreover, it is shown that GPX4 elicits diverse biological functions by suppressing phospholipid hydroperoxide at the expense of decreased glutathione (GSH), including loss of neurons, autophagy, cell repair, inflammation, ferroptosis, apoptosis, and oxidative stress. Interestingly, these processes are intimately related to the occurrence of fibrotic disease. Recently, GPX4 has been reported to exhibit a decline in fibrotic disease and inhibit fibrosis, suggesting that alterations of GPX4 can change the course or dictate the outcome of fibrotic disease. In this review, we summarize the role and underlying mechanisms of GPX4 in fibrosis diseases such as lung fibrosis, liver fibrosis, kidney fibrosis, cardiac fibrosis, and myelofibrosis.

Ferroptosis-related long non-coding RNA signature predicts the prognosis of hepatocellular carcinoma

Background: Hepatocellular Carcinoma (HCC) is a highly heterogeneous malignant tumor, and its prognostic prediction is extremely challenging. Ferroptosis is a cell mechanism dependent on iron, which is very significant for HCC development. Long non-coding RNA (lncRNA) is also linked to HCC progression. This work aimed to establish a prognosis risk model for HCC and to discover a possible biomarker and therapeutic target.

Methods: The Cancer Genome Atlas (TCGA) database was used to obtain RNA-seq transcriptome data and clinic information of HCC patients. Firstly, univariate Cox was utilized to identify 66 prognostic ferroptosis-related lncRNAs. Then, the identified lncRNAs were further included in the multivariate Cox analysis to construct the prognostic model. Eventually, we performed quantitative polymerase chain reaction (q-PCR) to validate the risk model.

Results: We established a prognostic seventeen-ferroptosis-related lncRNA signature model. The signature could categorize patients into two risk subgroups, with the low-risk subgroup associated with a better prognosis. Additionally, the area under the curve (AUC) of the lncRNAs signature was 0.801, indicating their reliability in forecasting HCC prognosis. Risk score was an independent prognostic factor by regression analyses. Gene set enrichment analysis (GSEA) analyses demonstrated a remarkable enrichment of cancer-related and immune-related pathways in the high-risk group. Besides, the immune status was decreased in the high-risk group. Eventually, three prognostic lncRNAs were validated in human HCCLM3 cell lines.

Conclusions: The risk model based on seventeen-ferroptosis-related lncRNA has significant prognostic value for HCC and may be therapeutic targets associated with ferroptosis in clinical ways.

Ferroptosis: A New Strategy for Cancer Therapy

Ferroptosis is a newly discovered form of iron-dependent cell death, which is different from other death forms. The main characteristics of ferroptosis are: (1) Amino acid metabolism. (2) Iron metabolism; (3) Lipid metabolism and Reactive oxygen species (ROS). Ferroptosis is related to the occurrence and development of a variety of cancers, especially in the drug resistance. This article reviews the research progress of iron death in tumors, and provides a theoretical reference for its further research and clinical application.

A Novel Predictive Model Incorporating Ferroptosis-Related Gene Signatures for Overall Survival in Patients with Lung Adenocarcinoma

BACKGROUND Lung adenocarcinoma (LUAD) is the predominant histological type of lung cancer with high morbidity and mortality. Ferroptosis is regarded as a new pattern of programmed cell death concerned with the progression of lung cancer characterized by lipid peroxidation. Nevertheless, the prognostic role of ferroptosis-related genes for LUAD warrant to be explored. MATERIAL AND METHODS RNA sequencing and relevant clinical patient data were obtained from public-access databanks. A prognostic model was constructed through the LASSO Cox regression in the cancer genome atlas cohort. The diagnostic value of the prognostic model was further evaluated in the gene expression omnibus cohort. RESULTS Most of the ferroptosis-related genes (69.9%) were differentially expressed between tumor and adjacent non-cancerous tissues. 43 differentially expressed genes showed a close association with the prognosis of LUAD patients (adjusted p-value <0.05). An 18-gene signature was built and applied to assign patients into high vs low-risk groups. Compared with the high-risk group, patients defined as the low-risk group suffered significantly prolonged OS. Both uni- and multivariate analyses demonstrated that the signature-based score served as a crucial role in influencing the OS of LUAD patients (hazard ratio >1, p<0.001). The immunity-related signaling pathway was enriched in the functional analysis and the infiltration of the immune cells showed a great difference between groups. CONCLUSIONS The predictive model could be applied for prognostic prediction for LUAD. Targeting ferroptosis could be a possible curative strategy against LUAD, and immunomodulation may be one of the potential mechanisms.

Clinical Significance and Immune Landscape of Recurrence-Associated Ferroptosis Signature in Early-Stage Lung Adenocarcinoma

BACKGROUND

The prevalence of patients newly diagnosed with early-stage lung adenocarcinoma (LUAD) is growing alongside significant advances in screening approaches. This study aimed to construct ferroptosis-related gene score (FRGscore) for predicting recurrence, explore immune-molecular characteristics, and determine the benefit of immunotherapy in distinct ferroptosis-based patterns and FRGscore-defined subgroups.

METHODS

A total of 1,085 early-stage LUAD patients from four independent cohorts were included. Consensus clustering analysis was performed using 217 co-expressed FRGs to explore different ferroptosis-mediated patterns. An FRG scoring system was established to predict relapse, quantify ferroptosis-mediated patterns, and evaluate the response to immunotherapy in individual patients based on Lasso-penalized and stepwise Cox regression analyses. Immune landscape involving multiple parameters was further evaluated, stratified by cluster subtypes and FRGscore subgroups.

RESULTS

Two ferroptosis-mediated patterns were identified and verified, which were characterized by significantly distinct prognosis and immune profiles. Analyses of immune characteristics showed that identified ferroptosis patterns were characterized as immune-inflamed phenotype and immune-exhausted phenotype. The FRG scoring model based on 11 FRG-derived signatures panel classified patients into the FRGscore-high and FRGscore-low subgroups. Significantly longer recurrence-free survival (RFS) and overall survival (OS) were observed in the FRGscore-low subgroup. FRGscore-low patients were characterized by higher tumor mutational burden (TMB), immunoscore, immunophenoscore, and PD-L1 expression level and were associated with lower Tumor Immune Dysfunction and Exclusion (TIDE) score, whereas the opposite was observed in FRGscore-high patients. Immune-active pathways were remarkably enriched in the FRGscore-low subgroup. This scoring model remained highly predictive of prognosis across different clinical, molecular, and immune subgroups. Further analysis indicated that FRGscore-low patients exhibited higher response to anti-PD-1/PD-L1 immunotherapy and better clinical benefits based on two independent immunotherapy cohorts.

CONCLUSION

The proposed FRGscore could highly distinguish the recurrence patterns and molecular and immune characteristics and could predict immunotherapy prognosis, potentially representing a powerful prognostic tool for further optimization of individuated treatment and management strategies in early-stage LUAD.

Establishment and Validation of a Ferroptosis-Related Gene Signature to Predict Overall Survival in Lung Adenocarcinoma

Background: Lung adenocarcinoma (LUAD) is the most common and lethal subtype of lung cancer. Ferroptosis, an iron-dependent form of regulated cell death, has emerged as a target in cancer therapy. However, the prognostic value of ferroptosis-related genes (FRGs)x in LUAD remains to be explored.

Methods: In this study, we used RNA sequencing data and relevant clinical data from The Cancer Genome Atlas (TCGA) dataset and Gene Expression Omnibus (GEO) dataset to construct and validate a prognostic FRG signature for overall survival (OS) in LUAD patients and defined potential biomarkers for ferroptosis-related tumor therapy.

Results: A total of 86 differentially expressed FRGs were identified from LUAD tumor tissues versus normal tissues, of which 15 FRGs were significantly associated with OS in the survival analysis. Through the LASSO Cox regression analysis, a prognostic signature including 11 FRGs was established to predict OS in the TCGA tumor cohort. Based on the median value of risk scores calculated according to the signature, patients were divided into high-risk and low-risk groups. Kaplan–Meier analysis indicated that the high-risk group had a poorer OS than the low-risk group. The area under the curve of this signature was 0.74 in the TCGA tumor set, showing good discrimination. In the GEO validation set, the prognostic signature also had good predictive performance. Functional enrichment analysis showed that some immune-associated gene sets were significantly differently enriched in two risk groups.

Conclusion: Our study unearthed a novel ferroptosis-related gene signature for predicting the prognosis of LUAD, and the signature may provide useful prognostic biomarkers and potential treatment targets.

Ferroptosis in Lung Cancer: From Molecular Mechanisms to Prognostic and Therapeutic Opportunities

Lung cancer is the second commonly diagnosed malignancy worldwide and has the highest mortality rate among all cancers. Tremendous efforts have been made to develop novel strategies against lung cancer; however, the overall survival of patients still is low. Uncovering underlying molecular mechanisms of this disease can open up new horizons for its treatment. Ferroptosis is a newly discovered type of programmed cell death that, in an iron-dependent manner, peroxidizes unsaturated phospholipids and results in the accumulation of radical oxygen species. Subsequent oxidative damage caused by ferroptosis contributes to cell death in tumor cells. Therefore, understanding its molecular mechanisms in lung cancer appears as a promising strategy to induce ferroptosis selectively. According to evidence published up to now, significant numbers of research have been done to identify ferroptosis regulators in lung cancer. Therefore, this review aims to provide a comprehensive standpoint of molecular mechanisms of ferroptosis in lung cancer and address these molecules’ prognostic and therapeutic values, hoping that the road for future studies in this field will be paved more efficiently.

A novel ferroptosis-related lncRNA signature for prognosis prediction in gastric cancer

Background

Gastric cancer (GC) is a common malignant cancer with a poor prognosis. Ferroptosis has been shown to play crucial roles in GC development. Long non-coding RNAs (lncRNAs) is also associated with tumor progression in GC. This study aimed to screen the prognostic ferroptosis-related lncRNAs and to construct a prognostic risk model for GC.

Methods

Ferroptosis-related lncRNAs from The Cancer Genome Atlas (TCGA) GC expression data was downloaded. First, single factor Cox proportional hazard regression analysis was used to select seven prognostic ferroptosis-related lncRNAs from TCGA database. And then, the selected lncRNAs were further included in the multivariate Cox proportional hazard regression analysis to establish the prognostic model. A nomogram was constructed to predict individual survival probability. Finally, we performed quantitative reverse transcription polymerase chain reaction (qRT-PCR) to verify the risk model.

Results

We constructed a prognostic ferroptosis-related lncRNA signature in this study. Kaplan-Meier curve analysis revealed a significantly better prognosis for the low-risk group than for the high-risk group (P = 2.036e-05). Multivariate Cox proportional risk regression analysis demonstrated that risk score was an independent prognostic factor [hazard ratio (HR) = 1.798, 95% confidence interval (CI) =1.410–2.291, P < 0.001]. A nomogram, receiver operating characteristic curve, and principal component analysis were used to predict individual prognosis. Finally, the expression levels of AP003392.1, AC245041.2, AP001271.1, and BOLA3-AS1 in GC cell lines and normal cell lines were tested by qRT-PCR.

Conclusions

This risk model was shown to be a novel method for predicting prognosis for GC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08975-2.

Comprehensive Analysis of Ferroptosis-Related Markers for the Clinical and Biological Value in Gastric Cancer

Gastric cancer is a highly malignant tumor with poor survival rate. Ferroptosis, a newly defined regulated cell death, is closely related to several tumors. Introduction of ferroptosis is promising for cancer treatments. However, the predictive role of ferroptosis in GC remains elusive. In this study, we screened the ferroptosis-related genes which were differentially expressed between normal and GC tissues. Then, based on these differentially expressed genes (DEGs), the least absolute shrinkage and selection operator (LASSO) and multivariate Cox regressions were applied to construct the 10-gene prognostic signature (SP1, MYB, ALDH3A2, KEAP1, AIFM2, ITGB4, TGFBR1, MAP1LC3B, NOX4, and ZFP36) in TCGA training dataset. Based on the median risk score, all GC patients in TCGA training dataset and GSE84437 testing dataset were classified into a high- or low-risk group. GC patients in the low-risk group showed significantly higher survival possibilities than those in the high-risk group (P < 0.001). Combined with the clinical characteristics, the risk score was proven as an independent factor for predicting the OS of GC patients. Besides, the GC patients in the high- or low-risk group showed significantly different GO and KEGG functional enrichments, somatic mutation, fractions of immune cells, and immunotherapy response. Then, the expression levels of these genes in signature were further verified in the GC cell lines and our own GC samples (30-paired tumor/normal tissues). Furthermore, the effects of ferroptosis inducer Erastin on these 10 ferroptosis-related genes in GC cell lines were also explored in our study. In conclusion, our study constructed a prognostic signature of 10 ferroptosis-related genes, which could well predict the prognosis and immunotherapy for GC patients.

The role of ferroptosis in lung cancer

Lung cancer is one of the most common cancers in the world. Although medical treatment has made impressive progress in recent years, it is still one of the leading causes of cancer-related deaths in men and women. Ferroptosis is a type of non-apoptotic cell death modality, usually characterized by iron-dependent lipid peroxidation, rather than caspase-induced protein cleavage. Excessive or lack of ferroptosis is associated with a variety of diseases, including cancer and ischaemia-reperfusion injury. Recent preclinical evidence suggests that targeting ferroptotic pathway is a potential strategy for the treatment of lung cancer. In this review, we summarize the core mechanism and regulatory network of ferroptosis in lung cancer cells, and highlight ferroptosis induction-related tumor therapies. The reviewed information may provide new insights for targeted lung cancer therapy.

Construction of a Prognostic Model in Lung Adenocarcinoma Based on Ferroptosis-Related Genes

Background: Lung adenocarcinoma is one of the most common malignant tumors of the respiratory system, ranking first in morbidity and mortality among all cancers. This study aims to establish a ferroptosis-related gene-based prognostic model to investigate the potential prognosis of lung adenocarcinoma. Methods: We obtained gene expression data with matching clinical data of lung adenocarcinoma from the The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. The ferroptosis-related genes (FRGs) were downloaded from three subgroups in the ferroptosis database. Using gene expression differential analysis, univariate Cox regression, and LASSO regression analysis, seven FRGs with prognostic significance were identified. The result of multivariate Cox analysis was utilized to calculate regression coefficients and establish a risk-score formula that divided patients with lung adenocarcinoma into high-risk and low-risk groups. The TCGA results were validated using GEO data sets. Then we observed that patients divided in the low-risk group lived longer than the overall survival (OS) of the other. Then we developed a novel nomogram including age, gender, clinical stage, TNM stage, and risk score. Results: The areas under the curves (AUCs) for 3- and 5-years OS predicted by the model were 0.823 and 0.852, respectively. Calibration plots and decision curve analysis also confirmed the excellent predictive performance of the model. Subsequently, gene function enrichment analysis revealed that the identified FRGs are important in DNA replication, cell cycle regulation, cell adhesion, chromosomal mutation, oxidative phosphorylation, P53 signaling pathway, and proteasome processes. Conclusions: Our results verified the prognostic significance of FRGs in patients with lung adenocarcinoma, which may regulate tumor progression in a variety of pathways.

Targeting Ferroptosis for Lung Diseases: Exploring Novel Strategies in Ferroptosis-Associated Mechanisms

Ferroptosis is an iron-dependent regulated necrosis characterized by the peroxidation damage of lipid molecular containing unsaturated fatty acid long chain on the cell membrane or organelle membrane after cellular deactivation restitution system, resulting in the cell membrane rupture. Ferroptosis is biochemically and morphologically distinct and disparate from other forms of regulated cell death. Recently, mounting studies have investigated the mechanism of ferroptosis, and numerous proteins play vital roles in regulating ferroptosis. With detailed studies, emerging evidence indicates that ferroptosis is found in multiple lung diseases, demonstrating that ferroptosis appears to be particularly important for lung diseases. The mounting interest in ferroptosis drugs specifically targeting the ferroptosis mechanism holds substantial therapeutic promise in lung diseases. The present review emphatically summarizes the functions and integrated molecular mechanisms of ferroptosis in various lung diseases, proposing that multiangle regulation of ferroptosis might be a promising strategy for the clinical treatment of lung diseases.

Ferroptosis: A New Promising Target for Lung Cancer Therapy

Ferroptosis is a new type of regulatory cell death that differs from autophagy, apoptosis, necrosis, and pyroptosis; it is caused primarily by the accumulation of iron and lipid peroxides in the cell. Studies have shown that many classical signaling pathways and biological processes are involved in the process of ferroptosis. In recent years, investigations have revealed that ferroptosis plays a crucial role in the progression of tumors, especially lung cancer. In particular, inducing ferroptosis in cells can inhibit the growth of tumor cells, thereby reversing tumorigenesis. In this review, we summarize the characteristics of ferroptosis from its underlying basis and role in lung cancer and provide possible applications for it in lung cancer therapies.

Establishment of a ferroptosis-related gene signature for prognosis in lung adenocarcinoma patients

Objective

Lung cancer is the most common malignancy worldwide and exhibits both high morbidity and mortality. In recent years, scientists have made substantial breakthroughs in the early diagnosis and treatment of lung adenocarcinoma (LUAD), however, patient prognosis still shows vast individual differences. In this study, bioinformatics methods were used to identify and analyze ferroptosis-related genes to establish an effective signature for predicting prognosis in LUAD patients.

Methods

The gene expression profiles of LUAD patients with complete clinical and follow-up information were downloaded from two public databases, univariate Cox regression and multivariate Cox regression analysis were used to obtain ferroptosis-related genes for constructing the prognos tic risk model, AUC and calibration plot were used to evaluate the predictive accuracy of the FRGS and nomogram.

Results

A total of 74 ferroptosis-related differentially expressed genes (DEGs) were identi fied between LUAD and normal tissues from The Cancer Genome Atlas (TCGA) database. A five-gene panel for prediction of LUAD prognosis was established by multivariate regression and was verified using the GSE68465 cohort from the Gene Expression Omnibus (GEO) database. Patients were divided into two different risk groups according to the median risk score of the five genes. Based on Kaplan-Meier (KM) analysi, the OS rate of the high-risk group was markedly worse than that of the low-risk group. We also found that risk score was an independent prognostic indicator. The receiver operating characteristic ROC curve showed that the proposed model had good prediction ability. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional analyses indicated that risk score was prominently enriched in ferroptosis processes. Moreover, at the score of immune-associated gene sets, significant differences were found between the two risk groups.

Conclusions

This study demonstrated that ferroptosis-related gene signatures can be used as a potential predictor for the prognosis of LUAD, thus providing a novel strategy for individualized treatment in LUAD patients.

Identification of a prognostic ferroptosis-related lncRNA signature in the tumor microenvironment of lung adenocarcinoma

Ferroptosis is closely linked to various cancers, including lung adenocarcinoma (LUAD); however, the factors involved in the regulation of ferroptosis-related genes are not well established. In this study, we identified and characterized ferroptosis-related long noncoding RNAs (lncRNAs) in LUAD. In particular, a coexpression network of ferroptosis-related mRNAs and lncRNAs from The Cancer Genome Atlas (TCGA) was constructed. Univariate and multivariate Cox proportional hazards analyses were performed to establish a prognostic ferroptosis-related lncRNA signature (FerRLSig). We obtained a prognostic risk model consisting of 10 ferroptosis-related lncRNAs: AL606489.1, AC106047.1, LINC02081, AC090559.1, AC026355.1, FAM83A-AS1, AL034397.3, AC092171.5, AC010980.2, and AC123595.1. High risk scores according to the FerRLSig were significantly associated with poor overall survival (hazard ratio (HR) = 1.412, 95% CI = 1.271–1.568; P < 0.001). Receiver operating characteristic (ROC) curves and a principal component analysis further supported the accuracy of the model. Next, a prognostic nomogram combining FerRLSig with clinical features was established and showed favorable predictive efficacy for survival risk stratification. In addition, gene set enrichment analysis (GSEA) revealed that FerRLSig is involved in many malignancy-associated immunoregulatory pathways. Based on the risk model, we found that the immune status and response to immunotherapy, chemotherapy, and targeted therapy differed significantly between the high-risk and low-risk groups. These results offer novel insights into the pathogenesis of LUAD, including the contribution of ferroptosis-related lncRNAs, and reveal a prognostic indicator with the potential to inform immunological research and treatment.

Knockdown of SFRS9 Inhibits Progression of Colorectal Cancer Through Triggering Ferroptosis Mediated by GPX4 Reduction

Ferroptosis, a newly discovered form of programmed cell death characterized by lipid peroxidation, crafts a new perspective on cancer treatment. Serine and arginine rich splicing factor 9 (SFRS9) is frequently described as a proto-oncogene in cervical and bladder cancer. However, the role of SFRS9 in colorectal cancer (CRC) and whether SFRS9 exerts its function associated with ferroptosis is largely unknown. Herein, we found that the expression of SFRS9 mRNA and protein in the CRC tissues was obviously higher than that in the paracancerous tissues. Function assays revealed that SFRS9 overexpression (SFRS9-OE) significantly promoted cell viability, cell cycle progression and colony formation of CRC cells. While SFRS9 knockdown by shRNAs transfection inhibited these progressions. Furthermore, cell death and lipid peroxidation induced by ferroptosis inducers erastin and sorafenib were suppressed by SFRS9-OE. Bioinformatics analysis indicated that SFRS9 can bind to peroxidase 4 (GPX4) mRNA which is a central regulator of ferroptosis. Western blot showed that GPX4 protein expression was clearly elevated upon SFRS9-OE, while it was decreased in SFRS9-inhibited CRC cells. RNA immunoprecipitation experiment was carried out in HCT116 cells to confirm the binding of SFRS9 and GPX4 mRNA specifically. SiGPX4 transfection reversed the inhibitory effects of SFRS9-OE on the erastin and sorafenib-induced ferroptosis. Consistent with our in vitro observations, SFRS9 promoted the growth of tumors while SFRS9 knockdown significantly inhibited tumor growth in nude mice. In conclusion, SFRS9 represents an obstructive factor to ferroptosis by upregulating GPX4 protein expression, and knocking down SFRS9 might be an effective treatment for CRC.

A novel ferroptosis-related genes model for prognosis prediction of lung adenocarcinoma

Background

Ferroptosis is a newly discovered form of cell death characterized by iron-dependent lipid peroxidation. This study aims to investigate the potential correlation between ferroptosis and the prognosis of lung adenocarcinoma (LUAD).

Methods

RNA-seq data were collected from the LUAD dataset of The Cancer Genome Atlas (TCGA) database. Based on ferroptosis-related genes, differentially expressed genes (DEGs) between LUAD and paracancerous specimens were identified. The univariate Cox regression analysis was performed to screen key genes associated with the prognosis of LUAD. LUAD patients were divided into the training set and validation set. Then, we screened out key genes and built a prognostic prediction model involving 5 genes using the least absolute shrinkage and selection operator (LASSO) regression with tenfold cross-validation and the multivariate Cox regression analysis. After dividing LUAD patients based on the median level of risk score as cut-off value, the generated prognostic prediction model was validated in the validation set. Moreover, we analyzed the somatic mutations, and estimated the scores of immune infiltration in the high-risk and low-risk groups. Functional enrichment analysis of DEGs was performed as well.

Results

High-risk scores indicated the worse prognosis of LUAD. The maximum area under curve (AUC) of the training set and the validation set in this study was 0.7 and 0.69, respectively. Moreover, we integrated the age, gender, and tumor stage to construct the composite nomogram. The charts indicated that the AUC of LUAD cases with the survival time of 1, 3 and 5 years was 0.698, 0.71 and 0.73, respectively. In addition, the mutation frequency of LUAD patients in the high-risk group was significantly higher than that in the low-risk group. Simultaneously, DEGs were mainly enriched in ferroptosis-related pathways by analyzing the functional results.

Conclusions

This study constructs a novel LUAD prognosis prediction model involving 5 ferroptosis-related genes, which can be used as a promising tool for decision-making of clinical therapeutic strategies of LUAD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01588-2.

Construction and validation of a 15-gene ferroptosis signature in lung adenocarcinoma

Background

Ferroptosis is a novel form of programmed cell death characterized by the excessive accumulation of intracellular iron and an increase in reactive oxygen species. Emerging studies have shown that ferroptosis plays a vital role in the progression of lung adenocarcinoma, but the effect of ferroptosis-related genes on prognosis has been poorly studied. The purpose of this study was to explore the prognostic value of ferroptosis-related genes.

Methods

Lung adenocarcinoma samples were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. The least absolute shrinkage and selection operator (LASSO) Cox regression algorithm was used to establish a predictive signature for risk stratification. Kaplan–Meier (K–M) survival analysis and receiver operating characteristic (ROC) curve analysis were conducted to evaluate the signature. We further explored the potential correlation between the risk score model and tumor immune status.

Results

A 15-gene ferroptosis signature was constructed to classify patients into different risk groups. The overall survival (OS) of patients in the high-risk group was significantly shorter than that of patients in the low-risk group. The signature could predict OS independent of other risk factors. Single-sample gene set enrichment analysis (ssGSEA) identified the difference in immune status between the two groups. Patients in the high-risk group had stronger immune suppression, especially in the antigen presentation process.

Conclusions

The 15-gene ferroptosis signature identified in this study could be a potential biomarker for prognosis prediction in lung adenocarcinoma. Targeting ferroptosis might be a promising therapeutic alternative for lung adenocarcinoma.

STYK1/NOK Promotes Metastasis and Epithelial-Mesenchymal Transition in Non-small Cell Lung Cancer by Suppressing FoxO1 Signaling

Aims

Serine/threonine/tyrosine kinase 1 (STYK1) has been previously shown to have oncogenic properties, and emerging evidence suggests that STYK1 expression correlates with epithelial-mesenchymal transition (EMT). However, the mechanism of STYK1 involvement in oncogenesis remains unknown. The present study aimed to elucidate how STYK1 expression level relates to the metastasis, migration, invasion, and EMT in non-small cell lung cancer (NSCLC) and to determine the molecular mechanism of STYK1 effects.

Methods

Serine/threonine/tyrosine kinase 1 (STYK1) expression level and its relationship with the prognosis of NSCLC were determined using the ONCOMINE database and clinical cases. Non-small cell lung cancer cell lines with the overexpression or knockdown of STYK1 were established to determine whether STYK1 promotes cell migration, invasion, and EMT in vitro and in vivo. In addition, a constitutively active FoxO1 mutant (FoxO1AAA) was used to examine the role of FoxO1 in the STYK1-mediated upregulation of metastasis and EMT in NSCLC.

Results

Serine/threonine/tyrosine kinase 1 (STYK1) was upregulated in NSCLC tissues and cell lines, and its overexpression correlated with poor prognosis in patients with NSCLC after surgery. Enhanced expression of STYK1 potentiated the migration, invasion, and EMT in SW900 cells, thereby promoting metastasis, whereas knockdown of STYK1 inhibited these cellular phenomena in Calu-1 cells. Furthermore, STYK1 expression was positively related to the level of phosphorylated-FoxO1, whereas the constitutively active FoxO1 mutant protected against the positive effect of STYK1 overexpression on cell migration, invasion, and EMT.

Conclusion

Serine/threonine/tyrosine kinase 1 (STYK1) was upregulated in NSCLC and correlated with poor clinical outcomes. In addition, STYK1 suppressed FoxO1 functions, thereby promoting metastasis and EMT in NSCLC.

Dihydroisotanshinone I induced ferroptosis and apoptosis of lung cancer cells

Danshen (Salvia miltiorrhiza Bunge) is broadly utilized in traditional Chinese medicine for lung cancer. However, it's exact effort and mechanism on lung cancer is fully unclear. In this study, we found that dihydroisotanshinone I (DT), a pure compound extracted from danshen, can inhibit the growth of A549 cells and H460 cells. DT also induced apoptosis and ferroptosis in these lung cancer cells. DT also blocking the protein expression of GPX4 (Glutathione peroxidase 4). For in vivo study, DT treatment can inhibit metastasis of A549 cells in the nude mice model without adverse effects on mice. In conclusion, DT inhibited the growth of lung cancer cells through apoptosis and ferroptosis and inhibited metastasis of A549 cells in the nude mice model. Further studies are warranted to validate the findings of this study.

A Promising Future of Ferroptosis in Tumor Therapy

Currently, mechanisms and therapeutic approaches have been thoroughly studied in various prevalent malignant tumors, such as breast and lung cancer. However, there is inevitable tumor progression and drug resistance. Uncovering novel treatment strategies to inhibit tumor development is important. Ferroptosis, a form of cell death associated with iron and lipid peroxidation, has drawn extensive attention. In this paper, we reviewed the underlying mechanisms of ferroptosis (i.e., iron, glutathione, and lipid metabolism) and its role in various tumors (i.e., lung cancer, liver carcinoma, breast cancer, and pancreatic cancer). Moreover, we summarized ferroptosis-related anti-tumor drugs and emphasized the potential of combined treatment of anti-tumor drugs and radiotherapy in an effort to provide novel anti-tumor treatments.

Identification of a ferroptosis-related gene signature (FRGS) for predicting clinical outcome in lung adenocarcinoma

Background

Lung adenocarcinoma (LUAD) is the most common pathological subtype of lung cancer. Ferroptosis, an oxidative, iron-dependent form of necrotic cell death, is highly associated with tumorigenesis and cancer progression. However, the prognostic value of ferroptosis progress in LUAD was still rarely be investigated.

Methods

Herein, we collected three mRNA expression profiles and 85 ferroptosis-related genes from public databases. The “limma” package was used to identify ferroptosis-related differentially expressed genes (DEGs). Univariate Cox regression analysis and LASSO regression analysis were applied to screen and develop a ferroptosis-related gene signature (FRGS) and a formula to calculate the risk score. Multivariate Cox regression analysis was implemented to determine independent prognostic predictors of overall survival (OS). The area under the receiver operating characteristic curve (AUC) and calibration plot were used to evaluate the predictive accuracy of the FRGS and nomogram.

Results

We developed a FRGS with five genes (CYBB, CISD1, FADD, SAT2, VDAC2). The AUC of the FRGS in TCGA cohort was 0.777 at 1-year, 0.721 at 3-year and 0.725 at 5-year, significantly superior to the AUC of TNM stage (1-year: 0.701, 3-year: 0.691, 5-year: 0.686). A similar phenomenon was observed in GEO cohort 1 and 2. Multivariate Cox regression analysis indicted TNM stage and risk score were independent prognostic predictors. Finally, we built a nomogram with TNM stage and FRGS, the AUCs of which markedly higher than that of FRGS or TNM stage alone.

Conclusion

We constructed a prognostic FRGS with five ferroptosis-related genes and a nomogram for predicting the 1-, 3- and 5-year survival rate of LUAD patients, which may provide a new understanding of the prognostic value of ferroptosis progress in LUAD and will benefit prognosis assessment of LUAD patients.

Ferroptosis: Biochemistry and Biology in Cancers

The challenge of eradicating cancer is that cancer cells possess diverse mechanisms to protect themselves from clinical strategies. Recently, ferroptosis has been shown to exhibit appreciable anti-tumor activity that could be harnessed for cancer therapy in the future. Ferroptosis is an iron-dependent form of regulated cell death that is characterized by the oxidization of polyunsaturated fatty acids (PUFAs) and accumulation of lipid peroxides. Ferroptosis has been closely correlated with numerous biological processes, such as amino acid metabolism, glutathione metabolism, iron metabolism, and lipid metabolism, as well as key regulators including GPX4, FSP1, NRF2, and p53. Although ferroptosis could be involved in killing various cancer cells, multiple aspects of this phenomenon remain unresolved. In this review, we summarize the biochemistry and biology of ferroptosis in diverse cancers and discuss the potential mechanisms of ferroptosis, which might pave the way for guiding cancer therapeutics.

Emerging mechanisms and targeted therapy of ferroptosis in cancer

Ferroptosis is an iron- and lipid reactive oxygen species (ROS)-dependent form of programmed cell death that is distinct from other forms of regulatory cell death at the morphological, biological, and genetic levels. Emerging evidence suggests critical roles for ferroptosis in cell metabolism, the redox status, and various diseases, such as cancers, nervous system diseases, and ischemia-reperfusion injury, with ferroptosis-related proteins. Ferroptosis is inhibited in diverse cancer types and functions as a dynamic tumor suppressor in cancer development, indicating that the regulation of ferroptosis can be utilized as an interventional target for tumor treatment. Small molecules and nanomaterials that reprogram cancer cells to undergo ferroptosis are considered effective drugs for cancer therapy. Here, we systematically summarize the molecular basis of ferroptosis, the suppressive effect of ferroptosis on tumors, the effect of ferroptosis on cellular metabolism and the tumor microenvironment (TME), and ferroptosis-inducing agents for tumor therapeutics. An understanding of the latest progress in ferroptosis could provide references for proposing new potential targets for the treatment of cancers.

Dysregulation of ferroptosis may involve in the development of non-small-cell lung cancer in Xuanwei area

The Xuanwei area of Yunnan Province, China, is one of the regions suffering from the highest occurrence and mortality rate of lung cancer in the world. Local residents tend to use bituminous coal as domestic fuel, which causes serious indoor air pollution and is established as the main carcinogen. After the local government carried out furnace and stove reform work, lung cancer rate including incidence and mortality among residents remains high. We herein wonder if there are specific mechanisms at protein level for the development of non-small-cell lung cancer (NSCLC) in this area. We investigated the changes of protein profiling in tumour of the patients from Xuanwei area. Tandem mass tag (TMT) was employed to screen the differential proteins between carcinoma and para-carcinoma tissues. We identified a total of 422 differentially expressed proteins, among which 162 proteins were significantly up-regulated and 260 were downregulated compared to para-carcinoma tissues. Many of the differentially expressed proteins were related to extracellular matrix (ECM)-receptor interaction, focal adhesion, PI3K/AKT pathway and ferroptosis. Further experiments on the two differential proteins, thioredoxin 2 (TXN2) and haptoglobin (HP), showed that the change of their expressions could make the lung cancer cell lines more resistant to erastin or RSL-induced ferroptosis in vitro, and promote the growth of tumour in nude mice. In conclusion, this study revealed that aberrant regulation of ferroptosis may involve in the development of lung cancer in Xuanwei area.

A ferroptosis-related gene signature predicts overall survival in patients with lung adenocarcinoma

Aims: To elucidate the association between ferroptosis-related genes and prognosis in patients with lung adenocarcinoma (LUAD). Materials & methods: A ferroptosis-related gene signature was made by lasso regression analysis through the LUAD datasets of the Cancer Genome Atlas. The prognostic value of the multigene signature was externally validated in the GSE72094 dataset from the Gene Expression Omnibus database. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analysis were used to explore underlying mechanisms. Results & conclusion: We established a novel ferroptosis-related gene signature for overall survival in LUAD that was predictive in both the training and validation cohorts. Immune-related pathways were significantly enriched, and immune status differed between the high- and low-risk groups. Targeting ferroptosis is a potential therapeutic option in LUAD. These results still need to be confirmed by more studies.

Mitochondrial dysfunction in neurological disorders: Exploring mitochondrial transplantation

Mitochondria are fundamental for metabolic homeostasis in all multicellular eukaryotes. In the nervous system, mitochondria-generated adenosine triphosphate (ATP) is required to establish appropriate electrochemical gradients and reliable synaptic transmission. Notably, several mitochondrial defects have been identified in central nervous system disorders. Membrane leakage and electrolyte imbalances, pro-apoptotic pathway activation, and mitophagy are among the mechanisms implicated in the pathogenesis of neurodegenerative diseases, such as Alzheimer's, Parkinson's, and Huntington's disease, as well as ischemic stroke. In this review, we summarize mitochondrial pathways that contribute to disease progression. Further, we discuss pathological states that damaged mitochondria impose on normal nervous system processes and explore new therapeutic approaches to mitochondrial diseases.

[Mechanism of Ferroptosis and Its Research Progress in Lung Cancer]

铁死亡是近年来发现的一种铁依赖性的程序性细胞死亡，这种死亡是脂质过氧化物和活性氧堆积引起的。而肺癌作为病死率最高的恶性肿瘤之一，关于肺癌中铁死亡的研究甚少。本文中我们综述了肺癌中铁死亡受抑制的研究进展，从铁死亡发生的不同途径来解释肺癌中铁死亡受抑制现象。此外，诱导铁死亡治疗癌症越来越受到重视，本文中我们介绍了四种铁死亡激活剂以及铁死亡治疗肺癌的新展望，以期为肺癌治疗提供新的思路。

Ferroptosis in Carcinoma: Regulatory Mechanisms and New Method for Cancer Therapy

Ferroptosis is a new form of programmed cell death with characteristic accumulation of reactive oxygen species (ROS) resulting from iron accumulation and lipid peroxidation. Ferroptosis is involved in many diseases, including cancer, and induction of ferroptosis has shown attractive antitumour activities. In this review, we summarize recent findings on the regulatory mechanisms of key regulators of ferroptosis, including the catalytic subunit solute carrier family 7 member 11 (SLC7A11), the glutathione peroxidase 4 (GPX4), p53 and non-coding RNAs, the correlations between ferroptosis and iron homeostasis or autophagy, ferroptosis-inducing agents and nanomaterials and the diagnostic and prognostic value of ferroptosis-associated genes in TCGA data.