The retinoblastoma (Rb) protein regulates ferroptosis induced by sorafenib in human hepatocellular carcinoma cells

Identification and verification of novel immune-related ferroptosis signature with excellent prognostic predictive and clinical guidance value in hepatocellular carcinoma

Background: Immunity and ferroptosis often play a synergistic role in the progression and treatment of hepatocellular carcinoma (HCC). However, few studies have focused on identifying immune-related ferroptosis gene biomarkers. Methods: We performed weighted gene co-expression network analysis (WGCNA) and random forest to identify prognostic differentially expressed immune-related genes (PR-DE-IRGs) highly related to HCC and characteristic prognostic differentially expressed ferroptosis-related genes (PR-DE-FRGs) respectively to run co-expression analysis for prognostic differentially expressed immune-related ferroptosis characteristic genes (PR-DE-IRFeCGs). Lasso regression finally identified 3 PR-DE-IRFeCGs for us to construct a prognostic predictive model. Differential expression and prognostic analysis based on shared data from multiple sources and experimental means were performed to further verify the 3 modeled genes' biological value in HCC. We ran various performance testing methods to test the model's performance and compare it with other similar signatures. Finally, we integrated composite factors to construct a comprehensive quantitative nomogram for accurate prognostic prediction and evaluated its performance. Results: 17 PR-DE-IRFeCGs were identified based on co-expression analysis between the screened 17 PR-DE-FRGs and 34 PR-DE-IRGs. Multi-source sequencing data, QRT-PCR, immunohistochemical staining and testing methods fully confirmed the upregulation and significant prognostic influence of the three PR-DE-IRFeCGs in HCC. The model performed well in the performance tests of multiple methods based on the 5 cohorts. Furthermore, our model outperformed other related models in various performance tests. The immunotherapy and chemotherapy guiding value of our signature and the comprehensive nomogram's excellent performance have also stood the test. Conclusion: We identified a novel PR-DE-IRFeCGs signature with excellent prognostic prediction and clinical guidance value in HCC.

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

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

Ferroptosis of immune cells in the tumor microenvironment

Ferroptosis is a distinct form of cell death driven by the accumulation of peroxidized lipids. Characterized by alterations in redox lipid metabolism, ferroptosis has been implicated in a variety of cellular processes, including cancer. Induction of ferroptosis is considered a novel way to kill tumor cells, especially cells resistant to radiation and chemotherapy. However, in recent years, a new paradigm has emerged. In addition to promoting tumor cell death, ferroptosis causes potent immune suppression in the tumor microenvironment (TME) by affecting both innate and adaptive immune responses. In this review, we discuss the dual role of ferroptosis in the antitumor and protumorigenic functions of immune cells in cancer. We suggest strategies for targeting ferroptosis, taking into account its ambiguous role in cancer.

"Double-edged sword" effect of reactive oxygen species (ROS) in tumor development and carcinogenesis

Reactive oxygen species (ROS) are small reactive molecules produced by cellular metabolism and regulate various physiological and pathological functions. Many studies have shown that ROS plays an essential role in the proliferation and inhibition of tumor cells. Different concentrations of ROS can have a "double-edged sword" effect on the occurrence and development of tumors. A certain concentration of ROS can activate growth-promoting signals, enhance the proliferation and invasion of tumor cells, and cause damage to biomacromolecules such as proteins and nucleic acids. However, ROS can enhance the body's antitumor signal at higher levels by initiating oxidative stress-induced apoptosis and autophagy in tumor cells. This review analyzes ROS's unique bidirectional regulation mechanism on tumor cells, focusing on the key signaling pathways and regulatory factors that ROS affect the occurrence and development of tumors and providing ideas for an in-depth understanding of the mechanism of ROS action and its clinical application.

Mechanism of sorafenib resistance associated with ferroptosis in HCC

Hepatocellular carcinoma (HCC) is the most familiar primary hepatic malignancy with a poor prognosis. The incidence of HCC and the associated deaths have risen in recent decades. Sorafenib is the first drug to be approved by the Food and Drug Administration (FDA) for routine use in the first-line therapy of patients with advanced HCC. However, only about 30% of patients with HCC will be benefited from sorafenib therapy, and drug resistance typically develops within 6 months. In recent years, the mechanisms of resistance to sorafenib have gained the attention of a growing number of researchers. A promising field of current studies is ferroptosis, which is a novel form of cell death differing from apoptosis, necroptosis, and autophagy. This process is dependent on the accumulation of intracellular iron and reactive oxygen species (ROS). Furthermore, the increase in intracellular iron levels and ROS can be significantly observed in cells resistant to sorafenib. This article reviews the mechanisms of resistance to sorafenib that are related to ferroptosis, evaluates the relationship between ferroptosis and sorafenib resistance, and explores new therapeutic approaches capable of reversing sorafenib resistance in HCC through the modulation of ferroptosis.

AKT activation because of PTEN loss upregulates xCT via GSK3β/NRF2, leading to inhibition of ferroptosis in PTEN-mutant tumor cells

Here, we show that the tumor suppressor phosphatase and tensin homolog deleted from chromosome 10 (PTEN) sensitizes cells to ferroptosis, an iron-dependent form of cell death, by restraining the expression and activity of the cystine/glutamate antiporter system Xc- (xCT). Loss of PTEN activates AKT kinase to inhibit GSK3β, increasing NF-E2 p45-related factor 2 (NRF2) along with transcription of one of its known target genes encoding xCT. Elevated xCT in Pten-null mouse embryonic fibroblasts increases the flux of cystine transport and synthesis of glutathione, which enhances the steady-state levels of these metabolites. A pan-cancer analysis finds that loss of PTEN shows evidence of increased xCT, and PTEN-mutant cells are resistant to ferroptosis as a consequence of elevated xCT. These findings suggest that selection of PTEN mutation during tumor development may be due to its ability to confer resistance to ferroptosis in the setting of metabolic and oxidative stress that occurs during tumor initiation and progression.

Ferroptosis: the vulnerability within a cancer monster

Treatment-resistant cancer, such as neuroendocrine prostate cancer (NEPC), is a lethal disease with limited therapeutic options. RB1 is a tumor suppressor gene that is lost in a majority of NEPC tumors. In this issue of the JCI, Wang and colleagues examined how RB1 loss may sensitize cancer cells to ferroptosis inducers through elevation of ACSL4, a key enzyme that promotes lipid peroxidation and triggers ferroptosis. We discuss a high potential of RB1-deficient cells to undergo ferroptosis due to the elevation of ACSL4. This is normally kept in check by abundant expression of GPX4, an antioxidant enzyme, in cancer cells. This balance, however, is tilted by GPX4 inhibitors, leading to massive ferroptosis. We highlight possible therapeutic strategies that exploit this inherent vulnerability for targeting RB1-deficient, treatment-resistant cancer.

Ferroptosis as an emerging therapeutic target in liver diseases

Ferroptosis is an iron-dependently nonapoptotic cell death characterized by excessive accumulation of lipid peroxides and cellular iron metabolism disturbances. Impaired iron homeostasis and dysregulation of metabolic pathways are contributors to ferroptosis. As a major metabolic hub, the liver synthesizes and transports plasma proteins and endogenous fatty acids. Also, it acts as the primary location of iron storage for hepcidin generation and secretion. To date, although the intricate correlation between ferroptosis and liver disorders needs to be better defined, there is no doubt that ferroptosis participates in the pathogenesis of liver diseases. Accordingly, pharmacological induction and inhibition of ferroptosis show significant potential for the treatment of hepatic disorders involved in lipid peroxidation. In this review, we outline the prominent features, molecular mechanisms, and modulatory networks of ferroptosis and its physiopathologic functions in the progression of liver diseases. Further, this review summarizes the underlying mechanisms by which ferroptosis inducers and inhibitors ameliorate liver diseases. It is noteworthy that natural active ingredients show efficacy in preclinical liver disease models by regulating ferroptosis. Finally, we analyze crucial concepts and urgent issues concerning ferroptosis as a novel therapeutic target in the diagnosis and therapy of liver diseases.

Ferroptosis regulates key signaling pathways in gastrointestinal tumors: Underlying mechanisms and therapeutic strategies

Ferroptosis is an emerging novel form of non-apoptotic, regulated cell death that is heavily dependent on iron and characterized by rupture in plasma membrane. Ferroptosis is distinct from other regulated cell death modalities at the biochemical, morphological, and molecular levels. The ferroptotic signature includes high membrane density, cytoplasmic swelling, condensed mitochondrial membrane, and outer mitochondrial rupture with associated features of accumulation of reactive oxygen species and lipid peroxidation. The selenoenzyme glutathione peroxidase 4, a key regulator of ferroptosis, greatly reduces the lipid overload and protects the cell membrane against oxidative damage. Ferroptosis exerts a momentous role in regulating cancer signaling pathways and serves as a therapeutic target in cancers. Dysregulated ferroptosis orchestrates gastrointestinal (GI) cancer signaling pathways leading to GI tumors such as colonic cancer, pancreatic cancer, and hepatocellular carcinoma. Crosstalk exists between ferroptosis and other cell death modalities. While apoptosis and autophagy play a detrimental role in tumor progression, depending upon the factors associated with tumor microenvironment, ferroptosis plays a decisive role in either promoting tumor growth or suppressing it. Several transcription factors, such as TP53, activating transcription factors 3 and 4, are involved in influencing ferroptosis. Importantly, several molecular mediators of ferroptosis, such as p53, nuclear factor erythroid 2-related factor 2/heme oxygenase-1, hypoxia inducible factor 1, and sirtuins, coordinate with ferroptosis in GI cancers. In this review, we elaborated on key molecular mechanisms of ferroptosis and the signaling pathways that connect ferroptosis to GI tumors.

Ferroptosis landscape in prostate cancer from molecular and metabolic perspective

Prostate cancer is a major disease that threatens men's health. Its rapid progression, easy metastasis, and late castration resistance have brought obstacles to treatment. It is necessary to find new effective anticancer methods. Ferroptosis is a novel iron-dependent programmed cell death that plays a role in various cancers. Understanding how ferroptosis is regulated in prostate cancer will help us to use it as a new way to kill cancer cells. In this review, we summarize the regulation and role of ferroptosis in prostate cancer and the relationship with AR from the perspective of metabolism and molecular pathways. We also discuss the feasibility of ferroptosis in prostate cancer treatment and describe current limitations and prospects, providing a reference for future research and clinical application of ferroptosis.

Ferroptosis in gastrointestinal cancer: From mechanisms to implications

Ferroptosis is a form of regulated cell death that is initiated by excessive lipid peroxidation that results in plasma membrane damage and the release of damage-associated molecular patterns. In recent years, ferroptosis has gained significant attention in cancer research due to its unique mechanism compared to other forms of regulated cell death, especially caspase-dependent apoptotic cell death. Gastrointestinal (GI) cancer encompasses malignancies that arise in the digestive tract, including the stomach, intestines, pancreas, colon, liver, rectum, anus, and biliary system. These cancers are a global health concern, with high incidence and mortality rates. Despite advances in medical treatments, drug resistance caused by defects in apoptotic pathways remains a persistent challenge in the management of GI cancer. Hence, exploring the role of ferroptosis in GI cancers may lead to more efficacious treatment strategies. In this review, we provide a comprehensive overview of the core mechanism of ferroptosis and discuss its function, regulation, and implications in the context of GI cancers.

LncRNA HCP5-Encoded Protein Regulates Ferroptosis to Promote the Progression of Triple-Negative Breast Cancer

BACKGROUND

Long non-coding RNAs (lncRNAs) are a class of RNA molecules that are longer than 200 nucleotides and were initially believed to lack encoding capability. However, recent research has found open reading frames (ORFs) within lncRNAs, suggesting that they may have coding capacity. Despite this discovery, the mechanisms by which lncRNA-encoded products are involved in cancer are not well understood. The current study aims to investigate whether lncRNA HCP5-encoded products promote triple-negative breast cancer (TNBC) by regulating ferroptosis.

METHODS

We used bioinformatics to predict the coding capacity of lncRNA HCP5 and conducted molecular biology experiments and a xenograft assay in nude mice to investigate the mechanism of its encoded products. We also evaluated the expression of the HCP5-encoded products in a breast cancer tissue microarray.

RESULTS

Our analysis revealed that the ORF in lncRNA HCP5 can encode a protein with 132-amino acid (aa), which we named HCP5-132aa. Further experiments showed that HCP5-132aa promotes TNBC growth by regulating GPX4 expression and lipid ROS level through the ferroptosis pathway. Additionally, we found that the breast cancer patients with high levels of HCP5-132aa have poorer prognosis.

CONCLUSIONS

Our study suggests that overexpression of lncRNA HCP5-encoded protein is a critical oncogenic event in TNBC, as it regulates ferroptosis. These findings could provide new therapeutic targets for the treatment of TNBC.

The advancements in targets for ferroptosis in liver diseases

Ferroptosis is a type of regulated cell death caused by iron overload and lipid peroxidation, and its core is an imbalance of redox reactions. Recent studies showed that ferroptosis played a dual role in liver diseases, that was, as a therapeutic target and a pathogenic factor. Therefore, herein, we summarized the role of ferroptosis in liver diseases, reviewed the part of available targets, such as drugs, small molecules, and nanomaterials, that acted on ferroptosis in liver diseases, and discussed the current challenges and prospects.

Ferroptosis: The functions of Nrf2 in human embryonic stem cells

Human embryonic stem cells (hESCs) have the capacity of self-renewal as well as differentiation towards three germ layer derivatives which makes them as a source of therapeutic application. hESCs are tremendously prone to cell death after dissociation into single cells. Therefore, it technically hinders their applications. Our recent study has revealed that hESCs can be prone to ferroptosis which differs from those in earlier explorations reporting that cellular detachment results in a process cited as anoikis. Ferroptosis occurs via increasing intracellular iron. Therefore, this form of programmed cell death is distinct from other cell deaths in terms of biochemistry, morphology, and genetics. Ferroptosis is found by excessive iron which plays an important part role in reactive oxygen species (ROS) generation through the Fenton reaction as a cofactor. Many genes are related to ferroptosis under the control of nuclear factor erythroid 2-related factor 2 (Nrf2) which is a transcription factor regulating the expression of genes to protect cells from oxidative stress. Nrf2 was demonstrated to take a perilous role in the suppression of ferroptosis by regulating the iron, antioxidant defense enzymes, usage, and restoration of glutathione, thioredoxin, and NADPH. Mitochondrial function is another target of Nrf2 to control cell homeostasis through the modulation of ROS production. In this review, we will give a succinct overview of lipid peroxidation and discuss the major players in the ferroptotic cascade. Additionally, we discussed the important role of the Nrf2 signaling pathway in mediating lipid peroxidation and ferroptosis, with a focus on known Nrf2 target genes that inhibit these processes and their possible role in hESCs.

Ferroptosis: From Basic Research to Clinical Therapeutics in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common and highly heterogeneous malignancies worldwide. Despite the rapid development of multidisciplinary treatment and personalized precision medicine strategies, the overall survival of HCC patients remains poor. The limited survival benefit may be attributed to difficulty in early diagnosis, the high recurrence rate and high tumor heterogeneity. Ferroptosis, a novel mode of cell death driven by iron-dependent lipid peroxidation, has been implicated in the development and therapeutic response of various tumors, including HCC. In this review, we discuss the regulatory network of ferroptosis, describe the crosstalk between ferroptosis and HCC-related signaling pathways, and elucidate the potential role of ferroptosis in various treatment modalities for HCC, such as systemic therapy, radiotherapy, immunotherapy, interventional therapy and nanotherapy, and applications in the diagnosis and prognosis of HCC, to provide a theoretical basis for the diagnosis and treatment of HCC to effectively improve the survival of HCC patients.

Ferroptosis-Related Metabolic Mechanism and Nanoparticulate Anticancer Drug Delivery Systems Based on Ferroptosis

Ferroptosis is a new type of cell death discovered in recent years that distinguishes from apoptosis and necrosis, mainly caused by the imbalance between the production and degradation of lipid reactive oxygen species in cells. Although the mechanism of ferroptosis is not yet clear, the phenomenon of ferroptosis has attracted widespread attention from researchers and has become a new hotspot in anti-tumor research. Studies have shown that ferroptosis is involved in the occurrence and development of a variety of diseases such as nervous system diseases, cardiovascular diseases and cancer. And inhibiting or inducing the occurrence of ferroptosis can effectively intervene in related diseases. At the same time, nanotechnology, by virtue of its distinct advantages, has been widely used in the development of nanodrug delivery systems. This review outlines current the advance on the intersection of ferroptosis and biomedical nanotechnology. In this review, the discovery and characteristics of ferroptosis, the mechanism of occurrence and the relationship with disease are summarized. More importantly, we summarized the strategies for inducing ferroptosis based on nanoparticulate drug delivery systems for cancer treatment.

The Emerging Role of Ferroptosis in Various Chronic Liver Diseases: Opportunity or Challenge

Ferroptosis is a recently identified iron-dependent form of intracellular lipid peroxide accumulation-mediated cell death. Different from other types of cell death mechanisms, it exhibits distinct biological and morphological features characterized by the loss of lipid peroxidase repair activity caused by glutathione peroxidase 4, the presence of redox-active iron, and the oxidation of phospholipids-containing polyunsaturated fatty acids. In recent years, studies have shown that ferroptosis plays a key role in various liver diseases such as alcoholic liver injury, non-alcoholic steatohepatitis, liver cirrhosis, and liver cancer. However, the mechanism of ferroptosis and its regulation on chronic liver disease are controversial among different types of cells in the liver. Herein, we summarize the current studies on mechanism of ferroptosis in chronic liver disease, aiming to outline the blueprint of ferroptosis as an effective option for chronic liver disease therapy.

Iron as a therapeutic target in chronic liver disease

It was clearly realized more than 50 years ago that iron deposition in the liver may be a critical factor in the development and progression of liver disease. The recent clarification of ferroptosis as a specific form of regulated hepatocyte death different from apoptosis and the description of ferritinophagy as a specific variation of autophagy prompted detailed investigations on the association of iron and the liver. In this review, we will present a brief discussion of iron absorption and handling by the liver with emphasis on the role of liver macrophages and the significance of the iron regulators hepcidin, transferrin, and ferritin in iron homeostasis. The regulation of ferroptosis by endogenous and exogenous mod-ulators will be examined. Furthermore, the involvement of iron and ferroptosis in various liver diseases including alcoholic and non-alcoholic liver disease, chronic hepatitis B and C, liver fibrosis, and hepatocellular carcinoma (HCC) will be analyzed. Finally, experimental and clinical results following interventions to reduce iron deposition and the promising manipulation of ferroptosis will be presented. Most liver diseases will be benefited by ferroptosis inhibition using exogenous inhibitors with the notable exception of HCC, where induction of ferroptosis is the desired effect. Current evidence mostly stems from in vitro and in vivo experimental studies and the need for well-designed future clinical trials is warranted.

The Roles of Iron and Ferroptosis in Human Chronic Diseases

Ferroptosis, an iron-dependent novel type of cell death, has been characterized as an excessive accumulation of lipid peroxides and reactive oxygen species. A growing number of studies demonstrate that ferroptosis not only plays an important role in the pathogenesis and progression of chronic diseases, but also functions differently in different diseases. As a double-edged sword, activation of ferroptosis could potently inhibit tumor growth and increase sensitivity to chemotherapy and immunotherapy in various cancer settings. Therefore, the development of more efficacious ferroptosis agonists or inhibitors remains the mainstay of ferroptosis-targeting strategy for cancer therapeutics or cardiovascular and cerebrovascular diseases and neurodegenerative diseases therapeutics.

Identification and Validation of a Novel Prognostic Signature Based on Ferroptosis-Related Genes in Ovarian Cancer

BACKGROUND

Ovarian cancer is the most lethal gynecological tumor, with a poor prognosis due to the lack of early symptoms, resistance to chemotherapy, and recurrence. Ferroptosis belongs to the regulated cell death family, and is characterized by iron-dependent processes. Here, comprehensive bioinformatics analysis was applied to explore a valuable prognostic model based on ferroptosis-related genes, which was further validated in clinical OC samples.

METHODS

mRNA data of normal and ovarian tumor samples were obtained separately from the GTEx and TCGA databases. The least absolute shrinkage and selection operator (LASSO) cox regression was applied to construct the prognostic model based on ferroptosis-associated genes. Expression of ALOX12 in OC cell lines, as well as cell functions, including proliferation and migration, were examined. Finally, the prognostic efficiency of the model was assessed in the clinical tissues of OC patients.

RESULTS

A gene signature consisting of ALOX12, RB1, DNAJB6, STEAP3, and SELENOS was constructed. The signature divided TCGA, ICGC, and GEO cohorts into high-risk and low-risk groups separately. Receiver operating characteristic (ROC) curves and independent prognostic factor analysis were carried out, and the prognostic efficacy was validated. The expression levels of ALOX12 in cell lines were examined. Inhibition of ALOX12 attenuated cell proliferation and migration in HEY cells. Moreover, the prognostic value of ALOX12 expression was examined in clinical samples of OC patients.

CONCLUSION

This work constructed a novel ferroptosis-associated gene model. Furthermore, the clinical predictive role of ALOX12 was identified in OC patients, suggesting that ALOX12 might act as a potential prognostic tool and therapeutic target for OC patients.

Combination Analysis of Ferroptosis and Immune Status Predicts Patients Survival in Breast Invasive Ductal Carcinoma

Ferroptosis is a new form of iron-dependent cell death and plays an important role during the occurrence and development of various tumors. Increasingly, evidence shows a convincing interaction between ferroptosis and tumor immunity, which affects cancer patients' prognoses. These two processes cooperatively regulate different developmental stages of tumors and could be considered important tumor therapeutic targets. However, reliable prognostic markers screened based on the combination of ferroptosis and tumor immune status have not been well characterized. Here, we chose the ssGSEA and ESTIMATE algorithms to evaluate the ferroptosis and immune status of a TCGA breast invasive ductal carcinoma (IDC) cohort, which revealed their correlation characteristics as well as patients' prognoses. The WGCNA algorithm was used to identify genes related to both ferroptosis and immunity. Univariate COX, LASSO regression, and multivariate Cox regression models were used to screen prognostic-related genes and construct prognostic risk models. Based on the ferroptosis and immune scores, the cohort was divided into three groups: a high-ferroptosis/low-immune group, a low-ferroptosis/high-immune group, and a mixed group. These three groups exhibited distinctive survival characteristics, as well as unique clinical phenotypes, immune characteristics, and activated signaling pathways. Among them, low-ferroptosis and high-immune statuses were favorable factors for the survival rates of patients. A total of 34 differentially expressed genes related to ferroptosis-immunity were identified among the three groups. After univariate, Lasso regression, and multivariate stepwise screening, two key prognostic genes (GNAI2, PSME1) were identified. Meanwhile, a risk prognosis model was constructed, which can predict the overall survival rate in the validation set. Lastly, we verified the importance of model genes in three independent GEO cohorts. In short, we constructed a prognostic model that assists in patient risk stratification based on ferroptosis-immune-related genes in IDC. This model helps assess patients' prognoses and guide individualized treatment, which also further eelucidatesthe molecular mechanisms of IDC.

Expression and Prognostic Significance of Ferroptosis-related Proteins SLC7A11 and GPX4 in Renal Cell Carcinoma

BACKGROUND

The ferroptosis inhibitory gene solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) inhibit ferroptosis in carcinoma cells. However, whether SLC7A11 and GPX4 serve as an oncogene in renal cell carcinoma (RCC) remains unclear.

METHODS

Immunohistochemistry (IHC) assays were performed to assess the expression of SLC7A11 and GPX4 in human RCC tissues. Clinical-pathological analysis was performed to explore the correlation between SLC7A11 and GPX4 expression. Kaplan-Meier survival analysis was performed to characterise the associations between protein expression and patient progressionfree survival (PFS).

RESULTS

The upregulation of SLC7A11 and GPX4 was detected by IHC in RCC tissues compared with that in normal renal tissues. Meanwhile, the expression level of SLC7A11 and GPX4 was correlated with tumour diameter and distant metastasis (P<0.05). Kaplan-Meier survival analysis indicated that patients with high SLC7A11 and GPX4 expression levels exhibited worse PFS than those with low SLC7A11 and GPX4 expression levels (P<0.05).

CONCLUSION

The upregulation of SLC7A11 and GPX4 expression was associated with poor prognosis in patients with RCC. SLC7A11 and GPX4 may serve as diagnostic and prognostic biomarkers for patients with RCC.

Ferroptosis and its interaction with tumor immune microenvironment in liver cancer

Exploring effective systemic treatments for liver cancer is still a great challenge worldwide. As a novel form of regulated cell death, ferroptosis has been paid more and more attention in the cancer research field. In recent years, targeting ferroptosis has become an encouraging strategy for liver cancer treatment. Cancer cells can be directly killed by inducing ferroptosis; in contrast, ferroptosis can also ameliorate the tumor immunosuppressive microenvironment and sensitize cancers to immunotherapy. Here, we summarize fully current progress in the iron homeostasis in the liver, the internal association between imbalanced iron homeostasis and ferroptosis in liver carcinogenesis and development, as well as ferroptosis-related regulators in liver cancer. Furthermore, we discuss thoroughly the interaction between ferroptosis and tumor immune microenvironment. Finally, we provide certainly a future insight on the potential value of ferroptosis in the immunotherapy of liver cancer.

Ferroptosis in hepatocellular carcinoma: mechanisms and targeted therapy

Hepatocellular carcinoma is the most prevalent form of primary liver cancer with a multifactorial aetiology comprising genetic, environmental, and behavioural factors. Evading cell death is a defining hallmark of hepatocellular carcinoma, underpinning tumour growth, progression, and therapy resistance. Ferroptosis is a form of nonapoptotic cell death driven by an array of cellular events, including intracellular iron overload, free radical production, lipid peroxidation and activation of various cell death effectors, ultimately leading to rupture of the plasma membrane. Although induction of ferroptosis is an emerging strategy to suppress hepatocellular carcinoma, malignant cells manage to develop adaptive mechanisms, conferring resistance to ferroptosis and ferroptosis-inducing drugs. Herein, we aim at elucidating molecular mechanisms and signalling pathways involved in ferroptosis and offer our opinions on druggable targets and new therapeutic strategy in an attempt to restrain the growth and progression of hepatocellular carcinoma through induction of ferroptotic cell death.

Elabela: Negative Regulation of Ferroptosis in Trophoblasts via the Ferritinophagy Pathway Implicated in the Pathogenesis of Preeclampsia

Preeclampsia is a leading contributor to increased maternal morbidity and mortality in the perinatal period. Increasing evidence demonstrates that ferroptosis is an essential mechanism for the pathogenesis of preeclampsia. Elabela is a novel small-molecule polypeptide, mainly expressed in embryonic and transplacental tissues, with an ability to promote cell proliferation and invasion. However, its specific regulatory mechanism in preeclampsia has not been completely elucidated. In this study, we first reveal an increased grade of ferroptosis accompanied by a downregulation of the expression of Elabela in preeclampsia placentas. We then confirm the presence of a ferroptosis phenotype in the placenta of the mouse PE-like model, and Elabela can reduce ferroptosis in the placenta and improve adverse pregnancy outcomes. Furthermore, we demonstrate that targeting Elabela alleviates the cellular dysfunction mediated by Erastin promoting increased lipid peroxidation in vitro. Subsequent mechanistic studies suggest that Elabela increases FTH1 levels by inhibiting the ferritinophagy pathway, and consequently chelates the intracellular labile iron pool and eventually arrests ferroptosis. In conclusion, Elabela deficiency exacerbates ferroptosis in the placenta, which is among the potential mechanisms in the pathogenesis of preeclampsia. Targeting the Elabela-ferritinophagy-ferroptosis signaling axis provides a new therapeutic intervention strategy to alleviate preeclampsia.

A prognostic risk prediction model based on ferroptosis-related long non-coding RNAs in bladder cancer: A bulk RNA-seq research and scRNA-seq validation

BACKGROUND

To construct a prognostic risk model of bladder cancer (BC) from the perspective of long non-coding RNAs (lncRNAs) and ferroptosis, in order to guide clinical prognosis and identify potential therapeutic targets.

METHODS

In-hours BC samples were collected from 4 patients diagnosed with BC, who underwent radical cystectomy. Single cell transcriptome sequencing was performed and Seurat package were used for quality control and secondary analysis. LncRNAs expression profiles of BC samples were extracted from The Cancer Genome Atlas database. And sex, age, tumor, node, metastasis stage and other clinical data was downloaded at the same time. Ferroptosis-related lncRNAs were identified by co-expression analysis. We constructed a risk model by Cox regression and least absolute shrinkage and selection operator regression analyses. The predictive strength of the risk model for overall survival (OS) of patients with BC was evaluated by the log-rank test and Kaplan-Meier method. Finally, the enrichment analysis was performed and visualized.

RESULTS

We identified and included 15 prognostic ferroptosis-related lncRNAs (AL356740.1, FOXC2AS1, ZNF528AS1, LINC02535, PSMB8AS1, AL590428.1, AP000347.2, OCIAD1-AS1, AP001347.1, AC104986.2, AC018926.2, LINC00867, AC099518.4, USP30-AS1, and ARHGAP5-AS1), to build our ferroptosis-related lncRNAs risk model. Using this risk model, BC patients were divided into high and low-risk groups, and their respective survival lengths were calculated. The results showed that the OS of the low-risk group was significantly longer than that of the high-risk group. A nomogram was utilized to predict the survival rate of BC patients. As indicated in the nomogram, risk score was the most important indicator of OS in patients with BC. The ferroptosis-related lncRNAs risk model is an independent tool for prognostic risk assessment in patients with BC. Single cell transcriptome sequencing suggests that ferroptosis-related lncRNAs express specifically in BC tumor microenvironment. AL356740.1, LINC02535 and LINC00867 were mainly expressed in tumor cells.

CONCLUSION

The risk model based on the ferroptosis-related lncRNAs and the genomic clinico-pathological nomogram could be used to accurately predict the prognosis of patients with BC. The lncRNAs used to build this model might become potential therapeutic targets in the future.

Targeting PCSK9 in Liver Cancer Cells Triggers Metabolic Exhaustion and Cell Death by Ferroptosis

Deregulated lipid metabolism is a common feature of liver cancers needed to sustain tumor cell growth and survival. We aim at taking advantage of this vulnerability and rewiring the oncogenic metabolic hub by targeting the key metabolic player pro-protein convertase subtilisin/kexin type 9 (PCSK9). We assessed the effect of PCSK9 inhibition using the three hepatoma cell lines Huh6, Huh7 and HepG2 and validated the results using the zebrafish in vivo model. PCSK9 deficiency led to strong inhibition of cell proliferation in all cell lines. At the lipid metabolic level, PCSK9 inhibition was translated by an increase in intracellular neutral lipids, phospholipids and polyunsaturated fatty acids as well as a higher accumulation of lipid hydroperoxide. Molecular signaling analysis involved the disruption of the sequestome 1/Kelch-like ECH-associated protein 1/nuclear factor erythroid 2-related factor 2 (p62/Keap1/Nrf2) antioxidative axis, leading to ferroptosis, for which morphological features were confirmed by electron and confocal microscopies. The anti-tumoral effects of PCSK9 deficiency were validated using xenograft experiments in zebrafish. The inhibition of PCSK9 was effective in disrupting the oncometabolic process, inducing metabolic exhaustion and enhancing the vulnerability of cancer cells to iron-triggered lipid peroxidation. We provide strong evidence supporting the drug repositioning of anti-PCSK9 approaches to treat liver cancers.

Targeting cell death pathways for cancer therapy: recent developments in necroptosis, pyroptosis, ferroptosis, and cuproptosis research

Many types of human cells self-destruct to maintain biological homeostasis and defend the body against pathogenic substances. This process, called regulated cell death (RCD), is important for various biological activities, including the clearance of aberrant cells. Thus, RCD pathways represented by apoptosis have increased in importance as a target for the development of cancer medications in recent years. However, because tumor cells show avoidance to apoptosis, which causes treatment resistance and recurrence, numerous studies have been devoted to alternative cancer cell mortality processes, namely necroptosis, pyroptosis, ferroptosis, and cuproptosis; these RCD modalities have been extensively studied and shown to be crucial to cancer therapy effectiveness. Furthermore, evidence suggests that tumor cells undergoing regulated death may alter the immunogenicity of the tumor microenvironment (TME) to some extent, rendering it more suitable for inhibiting cancer progression and metastasis. In addition, other types of cells and components in the TME undergo the abovementioned forms of death and induce immune attacks on tumor cells, resulting in enhanced antitumor responses. Hence, this review discusses the molecular processes and features of necroptosis, pyroptosis, ferroptosis, and cuproptosis and the effects of these novel RCD modalities on tumor cell proliferation and cancer metastasis. Importantly, it introduces the complex effects of novel forms of tumor cell death on the TME and the regulated death of other cells in the TME that affect tumor biology. It also summarizes the potential agents and nanoparticles that induce or inhibit novel RCD pathways and their therapeutic effects on cancer based on evidence from in vivo and in vitro studies and reports clinical trials in which RCD inducers have been evaluated as treatments for cancer patients. Lastly, we also summarized the impact of modulating the RCD processes on cancer drug resistance and the advantages of adding RCD modulators to cancer treatment over conventional treatments.

Role of ferroptosis inhibitors in the management of diabetes

Ferroptosis, the iron-dependent, lipid peroxide-mediated cell death, has garnered attention due to its critical involvement in crucial physiological and pathological cellular processes. Indeed, several studies have attributed its role in developing a range of disorders, including diabetes. As accumulating evidence further the understanding of ferroptotic mechanisms, the impact this specialized mode of cell death has on diabetic pathogenesis is still unclear. Several in vivo and in vitro studies have highlighted the association of ferroptosis with beta-cell death and insulin resistance, supported by observations of marked alterations in ferroptotic markers in experimental diabetes models. The constant improvement in understanding ferroptosis in diabetes has demonstrated it as a potential therapeutic target in diabetic management. In this regard, ferroptosis inhibitors promise to rescue pancreatic beta-cell function and alleviate diabetes and its complications. This review article elucidates the key ferroptotic pathways that mediate beta-cell death in diabetes, and its complications. In particular, we share our insight into the cross talk between ferroptosis and other hallmark pathogenic mediators such as oxidative and endoplasmic reticulum stress regulators relevant to diabetes progression. Further, we extensively summarize the recent developments on the role of ferroptosis inhibitors and their therapeutic action in alleviating diabetes and its complications.

Evaluation the Therapeutic Effect of Adipose-Derived Mesenchymal Stem Cells on Chronic Mild Stress by Activating PEBP1-GPX4 Axis in Ferroptosis Using qRT-PCR, Fluorescence Microscope and Iron Determination Analysis

About 50% of depressive patients failed to respond to the treatment, mainly because of insufficient knowledge about the pathogenesis of depression. The current study’s objectives were to look into the potential role of ferroptosis in the etiology of depression in the mice model of chronic mild stress (CMS) and investigate the effects of adipose-derived mesenchymal stem cells (ADSCs) on PEBP1-GPX4 axis controlled ferroptosis in mice. We grouped the male C57BL/6 mice randomly as follows: normal control (NC), CMS, and CMS+ADSCs. The second two groups’ animals were exposed to CMS for a total of six weeks. From the fourth week of modeling to the sixth week, cell therapy was given once a week. SPT, TST, FST, and NSFT behavior assessments were used to evaluate the depression-like behavior brought on by CMS. We selected the ferroptosis-related parameters, including the expression of GPX4, FTH1, ACSL4, and COX2. The amount of iron was determined in the hippocampus of the model organism by using the iron assay kit. By measuring the PEBP1 and ERK1/2 levels, as well as evaluating the expression of GFAP and IBA1, we assessed the biological function of astrocytes and microglia in mice hippocampus. It was found that six weeks after modeling in the CMS+ADSCs group, the mice’s depression-like behavior induced by CMS had significantly improved. We found a significantly changed level of genes, including GPX4, ACSL4, FTH1, COX2, ERK1/2, GFAP, PEBP1 and IBA1. Also, we found the differentiated level of total and ferric iron in our model mice. All these findings demonstrated that ADSCs had a therapeutic effect on CMS-induced depression-like behavior, probably by activating the PEBP1-GPX4 axis in ferroptosis. This anti-depression role of ADSCs may be associated with the activation of the PEBP1-GPX4 axis in ferroptosis, implying that regulation of ferroptosis is a crucial therapeutic target for depression.

PNO1 inhibits autophagy-mediated ferroptosis by GSH metabolic reprogramming in hepatocellular carcinoma

Effective strategies for hepatocellular carcinoma, which is the second leading cause of death worldwide, remain limited. A growing body of emerging evidence suggests that ferroptosis activation is a novel promising approach for the treatment of this malignancy. Nevertheless, the potential therapeutic targets and molecular mechanisms of ferroptosis remain elusive. In this study, we found that PNO1 is a bona fide inhibitor of ferroptosis and that autophagy induced by PNO1 promotes cystine/glutamate antiporter SLC7A11 while increasing the synthesis and accumulation of intracellular glutamate. This increase is followed by an equally proportional addition in cystine uptake, which consequently enhances system Xc^- activity that leads to the inhibition of ferroptosis. In the maintenance of redox homeostasis, system Xc^- activated via PNO1-autophagy metabolism is responsible for maintaining cysteine for glutathione (GSH) synthesis, and the final GSH metabolic reprogramming protects HCC cells from ferroptosis. The combination of PNO1 inhibition with drugs causing ferroptosis induction, particularly sorafenib, the first-line drug associated with ferroptosis in liver cancer shows therapeutic promise in vitro and in vivo. Together, our findings indicated that PNO1 protects HCC cells from ferroptotic death through autophagy-mediated GSH metabolic remodeling, and we identified a candidate therapeutic target that may potentiate the effect of ferroptosis-based antitumor therapy.

Ferroptosis: A new insight for treatment of acute kidney injury

Acute kidney injury (AKI), one of the most prevalent clinical diseases with a high incidence rate worldwide, is characterized by a rapid deterioration of renal function and further triggers the accumulation of metabolic waste and toxins, leading to complications and dysfunction of other organs. Multiple pathogenic factors, such as rhabdomyolysis, infection, nephrotoxic medications, and ischemia-reperfusion injury, contribute to the onset and progression of AKI. However, the detailed mechanism remains unclear. Ferroptosis, a recently identified mechanism of nonapoptotic cell death, is iron-dependent and caused by lipid peroxide accumulation in cells. A variety of studies have demonstrated that ferroptosis plays a significant role in AKI development, in contrast to other forms of cell death, such as apoptosis, necroptosis, and pyroptosis. In this review, we systemically summarized the definition, primary biochemical mechanisms, key regulators and associated pharmacological research progress of ferroptosis in AKI. We further discussed its therapeutic potential for the prevention of AKI, in the hope of providing a useful reference for further basic and clinical studies.

Arginase 2 negatively regulates sorafenib-induced cell death by mediating ferroptosis in melanoma

Ferroptosis, a newly defined and iron-dependent cell death, morphologically and biochemically differs from other cell deaths. Melanoma is a serious type of skin cancer, and the poor efficacy of current therapies causes a major increase in mortality. Sorafenib, a multiple kinase inhibitor, has been evaluated in clinical phase trials of melanoma patients, which shows modest efficacy. Emerging evidence has demonstrated that arginase 2 (Arg2), type 2 of arginase, is elevated in various types of cancers including melanoma. To investigate the role and underlying mechanism of Arg2 in sorafenib-induced ferroptosis in melanoma, reverse transcriptase-quantitative polymerase chain reaction, western blot analysis, adenovirus and lentivirus transduction, and in vivo tumor homograft model experiments were conducted. In this study, we show that sorafenib treatment leads to melanoma cell death and a decrease in Arg2 at both the mRNA and protein levels. Knockdown of Arg2 increases lipid peroxidation, which contributes to ferroptosis, and decreases the phosphorylation of Akt. In contrast, overexpression of Arg2 rescues sorafenib-induced ferroptosis, which is prevented by an Akt inhibitor. In addition, genetic and pharmacological suppression of Arg2 is able to ameliorate the anticancer activity of sorafenib in melanoma cells in vitro and in tumor homograft models. We also show that Arg2 suppresses ferroptosis by activating the Akt/GPX4 signaling pathway, negatively regulating sorafenib-induced cell death in melanoma cells. Our study not only uncovers a novel mechanism of ferroptosis in melanoma but also provides a new strategy for the clinical applications of sorafenib in melanoma treatment.

Ferroptosis: Shedding Light on Mechanisms and Therapeutic Opportunities in Liver Diseases

Cell death is a vital physiological or pathological phenomenon in the development process of the organism. Ferroptosis is a kind of newly-discovered regulated cell death (RCD), which is different from other RCD patterns, such as apoptosis, necrosis and autophagy at the morphological, biochemical and genetic levels. It is a kind of iron-dependent mode of death mediated by lipid peroxides and lipid reactive oxygen species aggregation. Noteworthily, the number of studies focused on ferroptosis has been increasing exponentially since ferroptosis was first found in 2012. The liver is the organ that stores the most iron in the human body. Recently, it was frequently found that there are different degrees of iron metabolism disorder and lipid peroxidation and other ferroptosis characteristics in various liver diseases. Numerous investigators have discovered that the progression of various liver diseases can be affected via the regulation of ferroptosis, which may provide a potential therapeutic strategy for clinical hepatic diseases. This review aims to summarize the mechanism and update research progress of ferroptosis, so as to provide novel promising directions for the treatment of liver diseases.

Development and validation of four ferroptosis-related gene signatures and their correlations with immune implication in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. This tumor presents with an insidious onset, rapid progression, and frequent recurrence. Ferroptosis is a newly discovered mode of programmed cell death that may play a key role in the progression of HCC. This study aimed to investigate the prognostic value of ferroptosis-related genes (FRGs) in HCC and their impact on tumor immune function, thereby providing new insights into targeted therapy for HCC. First, 43 differentially expressed FRGs were identified using the TCGA database, and four prognostically relevant methylation-driven FRGs (G6PD, HELLS, RRM2, and STMN1) were screened via survival and methylation analyses. Gene co-expression, mutation, and clinicopathological characterization indicated that these four pivotal FRGs play essential roles in tumor progression. We also validated these four genes using transcriptomic and proteomic data as well as cohort samples from our patients. Moreover, receiver operator characteristic (ROC) curves confirmed that the signatures of the four FRGs were independent prognostic factors in HCC. Gene set enrichment analysis of the four FRGs showed statistically significant associations with pathways related to HCC proliferation. Finally, the TIMER and TISIDB databases indicated that the four FRGs were statistically significantly correlated with tumor-infiltrating immune cells and immune checkpoint expression. Taken together, this study provides information guiding a novel therapeutic strategy targeting FRGs for HCC treatment.

The Relationship Between Ferroptosis and Diseases

Ferroptosis is an iron-dependent mode of cell death. It can occur through two major pathways, exogenous (or transporter-dependent) and endogenous (or enzyme-regulated) pathways are activated by biological or chemical inducers, and glutathione peroxidase activity is inhibited, which causes intracellular iron accumulation and lipid Peroxidation. Ferroptosis is closely related to the pathological process of many diseases. How to intervene in the occurrence and development of related diseases by regulating ferroptosis has become a hot research topic. At present, studies have shown that ferroptosis is found in common diseases such as tumors, inflammatory diseases, bacterial infections, pulmonary fibrosis, hepatitis, inflammatory bowel disease, neurodegenerative diseases, kidney injury, ischemia-reperfusion injury and skeletal muscle injury. This article reviews the characteristics and mechanism of ferroptosis, and summarizes how ferroptosis participates in the pathophysiological process in various systemic diseases of the body, which may provide new references for the treatment of clinical diseases in the future.

Targeting Ferroptosis by Ubiquitin System Enzymes: A Potential Therapeutic Strategy in Cancer

Ferroptosis is a novel type of regulated cell death driven by the excessive accumulation of iron-dependent lipid peroxidation. Therapy-resistant tumor cells, particularly those in the mesenchymal-like state and prone to metastasis, are highly susceptible to ferroptosis, suggesting that induction of ferroptosis in tumor cells is a promising strategy for cancer therapy. Although ferroptosis is regulated at various levels, ubiquitination is key to post-translational regulation of ferroptotic cell death. E3 ubiquitin ligases (E3s) and deubiquitinating enzymes (DUBs) are the most remarkable ubiquitin system enzymes, whose dysregulation accounts for the progression of multiple cancers. E3s are involved in the attachment of ubiquitin to substrates for their degradation, and this process is reversed by DUBs. Accumulating evidence has highlighted the important role of ubiquitin system enzymes in regulating the sensitivity of ferroptosis. Herein, we will portray the regulatory networks of ferroptosis mediated by E3s or DUBs and discuss opportunities and challenges for incorporating this regulation into cancer therapy.

The differential usage of molecular machinery in brain cancer patients with iron-enriched glioma environments

Gliomas are neuroepithelial tumors in the brain or spinal cord that arise from glial or precursor cells and include astrocytomas, oligodendrogliomas, and ependymomas. They are the most common malignant primary central nervous system tumors, representing 75% of cases in adults and 24% of all cases of primary brain and CNS tumors [1,2].

New perspectives on ferroptosis and its role in hepatocellular carcinoma

ABSTRACT

For a long time, the morbidity and mortality rates of hepatocellular carcinoma (HCC) have remained high. Since the concept of ferroptosis was introduced in 2012, researchers' perspectives have shifted toward finding novel ferroptosis-related treatment strategies, especially for tumors that are resistant to apoptosis. In recent years, there have been an increasing number of studies on ferroptosis, and these studies have found that ferroptosis has great potential and promise for cancer treatment. Ferroptosis is a kind of regulated cell death (RCD); unlike apoptosis, ferroptosis is an iron-dependent type of RCD driven by lipid peroxidation. The whole process of ferroptosis mainly revolves around three pathways (system xc-/ glutathione peroxidase 4 [GPX4]), lipid peroxidation, and iron metabolism), which are also regulated by various metabolic factors. This review will attempt to analyze the relationship between the system xc-/GPX4 pathway, lipid peroxidation, iron metabolism, and ferroptosis from three aspects (triggering, execution, and regulation), and the regulatory factors for ferroptosis will be summarized. In this review, we will also illustrate the relationship between ferroptosis and tumors as well as its application in tumors from the perspective of HCC. Finally, we will summarize the current limitations and needs and provide perspectives related to the focus of development in the future.

OIT3 serves as a novel biomarker of hepatocellular carcinoma by mediating ferroptosis via regulating the arachidonic acid metabolism

Background

Oncoprotein-Induced Transcript 3 Protein (OIT3) was identified as a liver-specific gene with abnormal expression in hepatocellular carcinoma (HCC). Herein, we aimed to examine the function and specific mechanism of OIT3 in HCC.

Methods

Bioinformatic analyses and tissue microarray via immunohistochemistry were used to validate the expression of OIT3 in HCC. The biofunctions of OIT3 in HCC were determined in vitro and in vivo. The mechanism was confirmed by RNA-Sequence and Western blotting. The uni- and multivariate analyses were used to identify the independent predictors for HCC.

Results

Low expression of OIT3 was observed in HCC and predicted a poor clinical outcome. Ectopic expression of OIT3 could inhibit the proliferation, migration, and invasion abilities of HCC cells. Mechanistically, OIT3 upregulated the expression of ALOX15 and CYP4F3, thus inducing arachidonic acid increase, ROS accumulation, and lipid peroxidation, and eventually causing ferroptosis. OIT3 was validated as a prognostic predictor for HCC patients.

Conclusions

Our findings revealed a novel role of OIT3 in the process of tumorigenesis of HCC. OIT3 inhibited reproliferation, migration, and invasion of HCC cells by triggering ferroptosis, which indicates that OIT3 could serve as a potential biomarker in HCC.

Human umbilical cord mesenchymal stem cells ameliorate erectile dysfunction in rats with diabetes mellitus through the attenuation of ferroptosis

Background

Erectile dysfunction (ED), as one of the most prevalent consequences in male diabetic patients, has a serious impact on men's physical and mental health, and the treatment effect of diabetic mellitus erectile dysfunction (DMED) is often worse. Therefore, the development of a novel therapeutic approach is urgent. As stem cells with high differentiation potential, human umbilical cord mesenchymal stem cells (HUCMSCs) have been widely used in the treatment of diseases in other systems, and are expected to be a promising strategy for the treatment of DMED. In this study, we investigated the role of HUCMSCs in managing erectile function in rat models of type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) and compared the effects of two different injection methods.

Methods

T1DM and T2DM ED rats were given labelled HUCMSCs by corpus cavernosum injection and tail vein injection, respectively. ICP and MAP were monitored simultaneously by electrical stimulation four weeks after injection to indicate the erectile function of rats. To track the development and colonisation capabilities of stem cells, we performed EdU assay with penile tissue. The histological changes of the penis were observed by hematoxylin–eosin staining, and Masson’s trichrome staining was conducted to evaluate the smooth muscle content and the degree of fibrosis in the rat penis. Then, we employed specific kits to measure the level of NO, cGMP, MDA, SOD and Fe in penis. Electron transmission microscopy was implemented to observe morphology of mitochondria. Besides, western blot and immunofluorescence staining were performed to demonstrate the expression of ferroptosis-related genes.

Results

We found that HUCMSCs improved erectile function in T1DM and T2DM ED rats, with no difference in efficacy between corpus cavernosum injection and tail vein injection. The EdU assay revealed that only a tiny percentage of HUCMSCs colonised the corpus cavernosum, while smooth muscle in the penis expanded and collagen decreased following HUCMSC injection. Moreover, the levels of oxidative stress in the penis of the rats given HUCMSCs were dramatically reduced, as was the tissue iron content. HUCMSCs normalised mitochondrial morphology within corpus cavernosum smooth muscle cells (CCSMCs), which were characteristically altered by high glucose. Furthermore, the expression of ferroptosis inhibitory genes SLC7A11 and GPX4 was obviously elevated in CCSMCs after stem cell management, but the abundances of ACSL4, LPCAT3 and ALOX15 showed the polar opposite tendency.

Conclusions

HUCMSCs can effectively and safely alleviate erectile dysfunction in T1DM and T2DM ED rats, while restoring erectile function by attenuating diabetes-induced ferroptosis in CCSMCs. Additionally, this study provides significant evidence for the development of HUCMSCs as a viable therapeutic strategy for DMED.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03147-w.

The Ferroptosis Molecular Subtype Reveals Characteristics of the Tumor Microenvironment, Immunotherapeutic Response, and Prognosis in Gastric Cancer

Ferroptosis is a relatively new form of programmed cell death, which can enhance the efficacy of tumor immunotherapy by regulating the tumor microenvironment (TME). In the face of the dilemma of a great difference in the efficacy of immunotherapy for gastric cancer (GC) patients, the exploration of ferroptosis may assist us in predicting immunotherapy efficacy prior to treatment. The potential role of ferroptosis in TME still needs further elucidation. Based on ferroptosis-related genes (FRGs), we systematically evaluated ferroptosis molecular subtypes in gastric cancer. Additionally, the association between these molecular subtypes and the characteristics of TME was examined. A ferroptosis score was constructed to further explore the predictive efficacy of ferroptosis on the immunotherapy response in gastric cancer. There were also 32 other cancers that were evaluated. Three molecular subtypes of ferroptosis in gastric cancer were identified. The three immunophenotypes of tumor immune inflamed, immune excluded, as well as immune desert were mostly in agreement with the TME features of these three subtypes. The individual tumor genetic variation, TME characteristics, immunotherapy response, and prognosis could be assessed by a ferroptosis score. High ferroptosis scores in gastric cancer suggest stromal activation and immunosuppression. It is noted that tumors with a low ferroptosis score are characterized by extensive tumor mutations as well as an immune activation, which are associated with an enhanced immunotherapy response and an improved prognosis. This study reveals that ferroptosis plays an integral role in the regulation of the tumor immune microenvironment. The ferroptosis score may serve as an independent prognostic factor for GC and will deepen our understanding of the TME infiltration mechanisms as well as lead to more rational immunotherapy regimens.

Ferroptosis-Related Long Noncoding RNAs Have Excellent Predictive Ability for Multiomic Characteristics of Bladder Cancer

Background

The role of ferroptosis-related long non-coding RNAs (lncRNAs) in bladder cancer remains elusive. This study is aimed at examining the prognostic role of ferroptosis-related lncRNAs in bladder cancer.

Materials and Methods

The transcriptomic matrix and clinical information of patients with bladder cancer were obtained from The Cancer Genome Atlas (TCGA) database. A ferroptosis-related lncRNA signature was developed via the least absolute shrinkage and selection operator (LASSO) analysis using data from the training cohort, and the signature was further validated using data from the test cohort. The role of AC006160.1, the most significant lncRNA in the risk signature, was examined in various cell lines including SV-HUC-1, BIU-87, HT-1376, T24, RT4, RT-112, 5637, and UMUC3. The pcDNA3.1-AC006160.1 plasmid was constructed and transfected into the bladder cancer cell lines T24 and BIU-87. In addition, cell proliferation, colony formation, transwell, and wound healing assays were performed to examine the biological function of AC006160.1 in T24 and BIU-87 cell lines.

Results

Two clusters were identified through consensus clustering based on prognostic ferroptosis-related lncRNAs. A 5-lncRNA risk signature was successfully constructed using data from the training cohort and validated using data from the test cohort. The risk signature had excellent ability to predict survival outcomes, clinical stages, pathological grades, expression of immune checkpoints, and immunotherapeutic responses in bladder cancer samples. Furthermore, AC006160.1 expression was found to be lower in the cancer cell lines BIU-87, T24, RT4, RT-112, and 5637 than in the normal control cell line SV-HUC-1. Cell proliferation, colony formation, transwell migration, and wound healing assays validated that overexpression of AC006160.1 significantly inhibited the proliferation and invasion abilities of both T24 and BIU-87 cells. Drug sensitivity analysis revealed that patients with high expression of AC006160.1 were sensitive to metformin and methotrexate, and the results were further validated via in vitro drug experiments.

Conclusions

Ferroptosis-related lncRNAs play a vital role in predicting the multiomic characteristics of bladder cancer. The lncRNA AC006160.1 serves as a protective factor for the development of bladder cancer.

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.

Cancer suppression by ferroptosis and its role in digestive system tumors

Cancer is the second leading cause of death worldwide, and digestive system tumors remain the leading malignancy in China, seriously endangering national health and imposing a huge economic burden. Ferroptosis is a form of cell death characterized by increased intracellular reduced iron and accumulated lipid peroxide. Recent studies have revealed that ferroptosis is closely related to the occurrence and treatment of cancer. Therefore, this paper reviews the studies on ferroptosis and cancer to explore the potential of ferroptosis in the treatment of malignant tumors, especially digestive system tumors, and to provide a new direction for developing treatment options.

Immunization Combined with Ferroptosis Related Genes to Construct a New Prognostic Model for Head and Neck Squamous Cell Carcinoma

Simple Summary

Immunity combined with ferroptosis is being considered as a new tumor treatment modality, and its regulation in head and neck squamous cell carcinoma is still unknown. The purpose of this study was to look into the potential molecular biological roles of immune ferroptosis genes in head and neck squamous cell carcinoma. The 12-IFRM signatures were successfully constructed and classified into high- and low-risk groups using the TCGA database and related data resources. In patients with head and neck squamous cell carcinoma, feature-based risk scores were more predictive of survival than traditional clinicopathological features. Furthermore, the expression of CD8⁺T cells and macrophage M0 differed significantly between the two groups. The expression of TNFSF9 and CD44 in the high-risk groups was significantly increased compared with the low-risk groups. Next, we found a higher proportion of high-risk mutations than in the low-risk group. In addition, the high-risk group was more sensitive to some chemotherapy drugs. Finally, we performed correlation analysis on the model genes. In this paper, the 12-IFRM signatures was developed with promising application prospects for predicting the clinical outcomes and treatment outcomes in head and neck squamous cell carcinoma.

Abstract

Ferroptosis is a new type of programmed cell death that plays a pivotal role in a variety of tumors. Moreover, immunity is closely related to ferroptosis. However, immune-ferroptosis-related mRNAs (IFRMs) are still not fully understood in the regulation of head and neck squamous cell carcinoma (HNSC). The purpose of this paper was to investigate the IFRMs prediction of HNSC and its possible molecular biological role. RNA-Seq and related clinical data were mined from the TCGA database, ImmPort database, GeneCards database, FerrDb database, and previous data. In R software, the “DESeq2” package was used to analyze the differential expression of IFRMs. We used univariate Cox analysis to judge the prognosis of the IFRMs. Using the least absolute shrinkage and selection operator (LASSO) and Cox regression, a prediction model for 12 IFRMs was established. In this study, the Kaplan–Meier survival curve and receiver operating characteristic (ROC) curve analysis were used to evaluate the prediction results. Moreover, factors such as immune landscape, somatic mutations, and drug susceptibility are also discussed. We successfully constructed the signature of 12-IFRMs. The two risk groups were classified according to the risk score obtained by this signature. Compared with conventional clinicopathological features, the characteristic-based risk score was more predictive of survival in patients with HNSC. Furthermore, the expression of CD8⁺T cells and macrophage M0 differed significantly between the two groups. Moreover, the expression of TNFSF9 and CD44 in high-risk groups was significantly increased compared with the low-risk groups. Then, we found a higher proportion of high-risk mutations than in the low-risk group. Next, the high-risk group was more sensitive to chemotherapy drugs such as bosutinib, docetaxel, erlotinib, gefitinib, imatinib, lapatinib, and sorafenib. Finally, an in-depth analysis of the association and potential value of the 12 genes was performed. In summary, the 12-IFRM signatures established in this paper had good application prospects and could be effectively used to predict the clinical outcome and treatment response of head and neck squamous cell carcinoma.

A Ferroptosis-Related LncRNA Signature Associated with Prognosis, Tumor Immune Environment, and Genome Instability in Hepatocellular Carcinoma

Background

Ferroptosis is an iron-dependent form of cell death. In this study, we identified ferroptosis-related long noncoding RNAs (FRlncRNAs) to investigate their association with hepatocellular carcinoma (HCC) in prognosis, tumor immune environment, and genome instability.

Methods

Transcriptome profile data of HCC were retrieved from a public database. FRlncRNAs were identified by co-expression analysis. Patients were randomly divided into training and test cohorts. Univariate Cox analysis and Least Absolute Shrinkage and Selection Operator (LASSO) Cox regression were performed to construct a risk model. Patients were divided into high- and low-risk groups based on the risk model. AUC and C index were used to assess the risk model. Survival analysis, immune status, and genome instability were compared between the two groups.

Results

Sixteen FRlncRNAs were identified and used to construct an FRlncRNA signature for the risk model. The Kaplan-Meier analysis revealed that patients in the high-risk group had poorer overall survival than patients in the low-risk group. The area under curve of the risk model was 0.879, 0.809, and 0.757 in the training cohort and 0.635, 0.688, and 0.739 in the test cohort at 1, 2, and 3 years, respectively. The risk model was an independent prognostic predictor and showed excellent prediction of prognosis compared with clinicopathological features. For the differentially expressed ferroptosis-related genes, many enriched metabolic pathways were identified in the functional enrichment analysis. Immune cells such as CD8+ T cells, macrophages M1, natural killer cells, and B cells, which may be associated with antitumor immune responses, differed between the high- and low-risk groups. Genome instability based on the risk model was also explored. A total of 61 genes were differently mutated between the two risk groups, and among them, TP53, HECW2, TRIM66, MCTP2, and KIAA1551 had the most significant mutation frequency differences.

Conclusion

The FRlncRNA signature is closely related with overall survival, tumor immune environment, and genome instability in HCC.

Perspectives and mechanisms for targeting ferroptosis in the treatment of hepatocellular carcinoma

Ferroptosis is a novel process of regulated cell death discovered in recent years, mainly caused by intracellular lipid peroxidation. It is morphologically manifested as shrinking of mitochondria, swelling of cytoplasm and organelles, rupture of plasma membrane, and formation of double-membrane vesicles. Work done in the past 5 years indicates that induction of ferroptosis is a promising strategy in the treatment of hepatocellular carcinoma (HCC). System xc^-/GSH/GPX4, iron metabolism, p53 and lipid peroxidation pathways are the main focus areas in ferroptosis research. In this paper, we analyze the ferroptosis-inducing drugs and experimental agents that have been used in the last 5 years in the treatment of HCC. We summarize four different key molecular mechanisms that induce ferroptosis, i.e., system xc^-/GSH/GPX4, iron metabolism, p53 and lipid peroxidation. Finally, we outline the prognostic analysis associated with ferroptosis in HCC. The findings summarized suggest that ferroptosis induction can serve as a promising new therapeutic approach for HCC and can provide a basis for clinical diagnosis and prevention of this disease.