Prognostic and Immunological Role of Key Genes of Ferroptosis in Pan-Cancer

Comprehensive cognition of yak (Bos grunniens) AIFM2 gene and its anti-ferroptosis role in bisphenol A-induced fetal fibroblast model

Apoptosis-inducing factor mitochondrion-associated 2 (AIFM2) has been identified as a gene with anti-ferroptosis properties. To explore whether AIFM2 exerts anti-ferroptosis role in yaks (Bos grunniens), we cloned yak AIFM2 gene and analyzed its biological characteristics. The coding region of AIFM2 had 1122 bp and encoded 373 amino acids, which was conserved in mammals. Next, RT-qPCR results showed an extensive expression of AIMF2 in yak tissues. Furthermore, we isolated yak skin fibroblasts (YSFs) and established a bisphenol A (BPA)-induced ferroptosis model to further investigate the role of AIFM2. BPA elevated oxidative stress (reactive oxygen species, ROS) and lipid peroxidation (malondialdehyde, MDA and BODIPY), and reduced cell viability and antioxidant capacity (glutathione, GSH), with the severity depending on the dosage. Of note, a supplement of Ferrostatin-1 (Fer), an inhibitor of ferroptosis, restored the previously mentioned indicators. Subsequently, we constructed an AIFM2 overexpression vector and designed AIFM2 specific interfering siRNAs, which were transfected into YSFs. The results showed that overexpressing AIFM2 alleviated ferroptosis, characterizing by significant changes of cell viability, ROS, BODIPY, MDA and GSH. Meanwhile, interfering AIFM2 aggravated ferroptosis, demonstrating the critical anti-ferroptosis role of the yak AIFM2 gene. This study shed light on further exploring the molecular mechanism of AIFM2 in plateau adaptability.

Silencing CK19 regulates ferroptosis by affecting the expression of GPX4 and ACSL4 in oral squamous cell carcinoma in vivo and in vitro

To analyze the mechanism of how interfering with the cytokeratin 19 (CK19) pathway via the ferroptosis pathway affects tumor biological behaviors in the process of oral squamous cell carcinoma (OSCC) development. TCGA was used to analyze the expression of CK19 in pan-cancer and head and neck squamous cell carcinoma (HNSC) and to explore the ferroptosis-related genes related to HNSC. The effect of silencing CK19 on the migration ability of HSC-4 cells was verified by wound healing and migration assay. HSC-4 cells with silencing of CK19 and tumor-bearing nude mouse model were constructed. RT-qPCR, immunofluorescence and western blot were used to analyze the expression of ferroptosis-related genes. CK19 is highly expressed in human OSCC and nude mice. The migration ability of cells in the CK19-silenced group was lower than that of the control group. In vivo and in vitro, CK19 was negatively correlated with the expression of ACSL4 and positively correlated with the expression of GPX4. Compared with the control group, GPX4 expression was down-regulated and ACSL4 expression was up-regulated in the CK19-silenced group. Silencing CK19 also increased intracellular Fe2+ content and MDA content. Silencing CK19 can affect the expression of GPX4 and ACSL4 to regulate ferroptosis and at the same time increase the content of MDA, Fe2+ and ROS levels, thereby activating the regulation of ferroptosis pathway in the development of OSCC.

Olive Flounder By-Product Prozyme2000P Hydrolysate Ameliorates Age-Related Kidney Decline by Inhibiting Ferroptosis

This study explores olive flounder by-product Prozyme2000P (OFBP) hydrolysate as a potential treatment for age-related kidney decline. Ferroptosis, a form of cell death linked to iron overload and oxidative stress, is increasingly implicated in aging kidneys. We investigated whether OFBP could inhibit ferroptosis and improve kidney health. Using TCMK-1 cells, we found that OFBP treatment protected cells from ferroptosis induced by sodium iodate (SI). OFBP also preserved the mitochondria health and influenced molecules involved in ferroptosis regulation. In aging mice, oral administration of OFBP significantly improved kidney health markers. Microscopic examination revealed reduced thickening and scarring in the kidney's filtering units, a hallmark of aging. These findings suggest that OFBP hydrolysate may be a promising therapeutic candidate for age-related kidney decline. By inhibiting ferroptosis, OFBP treatment appears to improve both cellular and structural markers of kidney health. Further research is needed to understand how OFBP works fully and test its effectiveness in more complex models.

Mediation of Ferroptosis Suppressor Protein 1 Expression via 4-Hydroxy-2-Nonenal Accumulation Contributes to Acquisition of Resistance to Apoptosis and Ferroptosis in Diffuse Large B-Cell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma. New therapeutic strategies are needed for the treatment of refractory DLBCL. 4-Hydroxy-2-nonenal (4-HNE) is a cytotoxic lipid peroxidation marker, which alters intracellular signaling and induces genetic mutations. Lipid peroxidation is associated with nonapoptotic cell death, called ferroptosis. However, the relationship between 4-HNE accumulation and feroptotic regulators in DLBCL has not been fully evaluated. Here, we aimed to evaluate the accumulation of lipid peroxide and the expression of ferroptosis suppressor protein 1 (FSP1) in DLBCL using immunohistochemistry. We found a significant increase in the expression of FSP1 in cases with nuclear 4-HNE accumulation (P = .021). Both nuclear and cytoplasmic 4-HNE accumulation and FSP1 positivity were independent predictors of worse prognosis. In vitro exposure to 4-HNE resulted in its concentration- and time-dependent intracellular accumulation and increased expression of FSP1. Furthermore, short-term (0.25 and 1.0 μM) or long-term (0.25 μM) exposure to 4-HNE induced resistance to not only apoptosis but also ferroptosis. Taken together, regulation of FSP1 through 4-HNE accumulation may attenuate resistance to cell death in treatment-resistant DLBCL and might help develop novel therapeutic strategies for refractory DLBCL.

Mitochondrial regulation of GPX4 inhibition-mediated ferroptosis in acute myeloid leukemia

Resistance to apoptosis in acute myeloid leukemia (AML) cells causes refractory or relapsed disease, associated with dismal clinical outcomes. Ferroptosis, a mode of non-apoptotic cell death triggered by iron-dependent lipid peroxidation, has been investigated as potential therapeutic modality against therapy-resistant cancers, but our knowledge of its role in AML is limited. We investigated ferroptosis in AML cells and identified its mitochondrial regulation as a therapeutic vulnerability. GPX4 knockdown induced ferroptosis in AML cells, accompanied with characteristic mitochondrial lipid peroxidation, exerting anti-AML effects in vitro and in vivo. Electron transport chains (ETC) are primary sources of coenzyme Q10 (CoQ) recycling for its function of anti-lipid peroxidation in mitochondria. We found that the mitochondria-specific CoQ potently inhibited GPX4 inhibition-mediated ferroptosis, suggesting that mitochondrial lipid redox regulates ferroptosis in AML cells. Consistently, Rho0 cells, which lack functional ETC, were more sensitive to GPX4 inhibition-mediated mitochondrial lipid peroxidation and ferroptosis than control cells. Furthermore, degradation of ETC through hyperactivation of a mitochondrial protease, caseinolytic protease P (ClpP), synergistically enhanced the anti-AML effects of GPX4 inhibition. Collectively, our findings indicate that in AML cells, GPX4 inhibition induces ferroptosis, which is regulated by mitochondrial lipid redox and ETC.

Vitamin E/Coenzyme Q-Dependent "Free Radical Reductases": Redox Regulators in Ferroptosis

Significance: Lipid peroxidation and its products, oxygenated polyunsaturated lipids, act as essential signals coordinating metabolism and physiology and can be deleterious to membranes when they accumulate in excessive amounts. Recent Advances: There is an emerging understanding that regulation of polyunsaturated fatty acid (PUFA) phospholipid peroxidation, particularly of PUFA-phosphatidylethanolamine, is important in a newly discovered type of regulated cell death, ferroptosis. Among the most recently described regulatory mechanisms is the ferroptosis suppressor protein, which controls the peroxidation process due to its ability to reduce coenzyme Q (CoQ). Critical Issues: In this study, we reviewed the most recent data in the context of the concept of free radical reductases formulated in the 1980-1990s and focused on enzymatic mechanisms of CoQ reduction in different membranes (e.g., mitochondrial, endoplasmic reticulum, and plasma membrane electron transporters) as well as TCA cycle components and cytosolic reductases capable of recycling the high antioxidant efficiency of the CoQ/vitamin E system. Future Directions: We highlight the importance of individual components of the free radical reductase network in regulating the ferroptotic program and defining the sensitivity/tolerance of cells to ferroptotic death. Complete deciphering of the interactive complexity of this system may be important for designing effective antiferroptotic modalities. Antioxid. Redox Signal. 40, 317-328.

VSIG4 ameliorates intestinal inflammation through inhibiting macrophages NLRP3 inflammasome and pyroptosis

Inflammatory bowel disease (IBD) is one of the most common diseases in the digestive system related to aberrant inflammation. V-set and immunoglobulin domain-containing 4 (VSIG4), a type I transmembrane receptor exclusively expressed in a subset of tissue-resident macrophages, has been reported to exert anti-inflammatory activity in immune-related diseases, which has been not explored in IBD yet. This study aims to explore the role and the potential mechanism of VSIG4 in IBD. Clinical samples were obtained from IBD patients and were examined by immunohistochemical staining. THP-1 cells were differentiated into macrophages, and then stimulated with IL-4 plus IL-13 or LPS to induce pro-inflammatory (M1) or anti-inflammatory (M2) phenotype. Cell transfection was conducted to overexpress VSIG4. Western blot and immunofluorescence assays were performed to assess NLRP3 inflammasome- and pyroptosis-related proteins. Cytokines were measured using ELISA. A cell co-culture model of Caco-2 cells and VSIG4-mediated macrophages were established. Cell viability and apoptosis was examined by CCK-8 and flow cytometry assays, respectively. VSIG4 was downregulated in IBD and was negatively correlated with NLRP3 inflammasome. M1 macrophages exhibited higher levels of NLRP3 inflammasome, pyroptosis and inflammatory response than M2 macrophages, while VSIG4 overexpression efficiently reversed these changes in M1 macrophages. In addition, VSIG4 overexpression partly abolished M1 macrophages-induced cell viability loss, inflammatory response, apoptosis and pyroptosis in Caco-2 cells. Collectively, VSIG4 might alleviate intestinal inflammation through regulating M1/M2 macrophages, providing novel insights for the treatment of human IBD.

Single-cell data revealed CD14-type and FCGR3A-type macrophages and relevant prognostic factors for predicting immunotherapy and prognosis in stomach adenocarcinoma

Background

Stomach adenocarcinoma (STAD) exhibits profound tumor heterogeneity and represents a great therapeutic challenge. Single-cell sequencing technology is a powerful tool to identify characteristic cell types.

Methods

Single-cell sequencing data (scRNA-seq) GSE167297 and bulk RNA-seq data from TCGA, GTEx, GSE26901 and GSE15459 database were included in this study. By downscaling and annotating the cellular data in scRNA-seq, critical cell types in tumor progression were identified by AUCell score. Relevant gene modules were then identified by weighted gene co-expression network analysis (WGCNA). A prognostic scoring system was constructed by identifying prognostic factors in STAD by Least absolute shrinkage and selection operator (LASSO) COX model. The prognosis and model performance in the RiskScore groups were measured by Kaplan-Meier (K-M) curves and Receiver operating characteristic (ROC) curves. Nomogram was drawn based on RiskScore and prognosis-related clinical factors. In addition, we evaluated patient's feedback on immunotherapy in the RiskScore groups by TIMER, ESTIMATE and TIDE analysis. Finally, the expression levels of prognostic factors were verified in gastric cancer cell lines (MKN7 and MKN28) and human normal gastric mucosal epithelial cells (GES-1), and the effects of prognostic factors on the viability of gastric cancer cells were examined by the CCK8 assay and cell cycle.

Results

scRNA-seq analysis revealed that 11 cell types were identified, and macrophages exhibited relatively higher AUCell scores and specifically expressed CD14 and FCGR3A. High macrophage scores worsened the prognosis of STAD patients. We intersected the specifically expressed genes in macrophages subgroups (670) and macrophage module genes (2,360) obtained from WGCNA analysis. Among 86 common genes, seven prognostic factors (RGS2, GNAI2, ANXA5, MARCKS, CD36, NRP1 and PDE4A) were identified and composed a RiskScore model. Patients in low Risk group showed a better survival advantage. Nomogram also provided a favorable prediction for survival at 1, 3 and 5 years in STAD patients. Besides, we found positive feedback to immunotherapy in patients with low RiskScore. The expression tendency of the seven prognostic factors in MKN7 and MKN28 was consistent with that in the RNA-seq data in addition to comparison of protein expression levels in the public HPA (The Human Protein Atlas) database. Further functional exploration disclosed that MARCKS was an important prognostic factor in regulating cell viability in STAD.

Conclusion

This study preliminary uncovered a single cell atlas for STAD patients, and Macrophages relevant gene signature and nomogram displayed favorable immunotherapy and prognostic prediction ability. Collectively, our work provides a new insight into the molecular mechanisms and therapeutic approach for LUAD patients.

Suppression of the SLC7A11/glutathione axis causes ferroptosis and apoptosis and alters the mitogen-activated protein kinase pathway in nasopharyngeal carcinoma

SLC7A11 is a unit of the glutamate cystine antiporter Xc- system. It functions to import cystine for glutathione biosynthesis and maintains the redox balance in cells. Sorafenib inhibits the transporter activity of SLC7A11. The use of sorafenib has been approved in the treatment of multiple cancers. However, at present, our understanding of the mechanism of SLC7A11 and sorafenib in nasopharyngeal carcinoma (NPC) remains limited. We found that the expression of SLC7A11 was upregulated in NPC. A high SLC7A11 expression was associated with poor prognosis, metastasis, and an advanced T stage, which can be used as an independent prognostic indicator of NPC. In vitro, we observed that NPC cells relied on cystine for survival. Targeting SLC7A11 resulted in glutathione biosynthesis limitation, intracellular reactive oxygen species accumulation, lipid peroxides, ferroptosis, and apoptosis. Meanwhile, it altered mitogen activated protein kinase pathway, including p38 activation but ERK inhibition in NPC. This limited the proliferation of NPC cells. Sorafenib inhibited the proliferation and induced the death of NPC cells in vivo. In conclusion, SLC7A11 plays an important role in the occurrence and progression of NPC and may be a novel target for NPC treatment.

Inflammation-Associated Cytotoxic Agents in Tumorigenesis

Chronic inflammatory processes are related to all stages of tumorigenesis. As inflammation is closely associated with the activation and release of different cytotoxic agents, the interplay between cytotoxic agents and antagonizing principles is highlighted in this review to address the question of how tumor cells overcome the enhanced values of cytotoxic agents in tumors. In tumor cells, the enhanced formation of mitochondrial-derived reactive species and elevated values of iron ions and free heme are antagonized by an overexpression of enzymes and proteins, contributing to the antioxidative defense and maintenance of redox homeostasis. Through these mechanisms, tumor cells can even survive additional stress caused by radio- and chemotherapy. Through the secretion of active agents from tumor cells, immune cells are suppressed in the tumor microenvironment and an enhanced formation of extracellular matrix components is induced. Different oxidant- and protease-based cytotoxic agents are involved in tumor-mediated immunosuppression, tumor growth, tumor cell invasion, and metastasis. Considering the special metabolic conditions in tumors, the main focus here was directed on the disturbed balance between the cytotoxic agents and protective mechanisms in late-stage tumors. This knowledge is mandatory for the implementation of novel anti-cancerous therapeutic approaches.

The Evaluation of Prognostic Value and Immune Characteristics of Ferroptosis-Related Genes in Lung Squamous Cell Carcinoma

Background  The purpose of our study was to construct a prognostic model based on ferroptosis-related gene signature to improve the prognosis prediction of lung squamous carcinoma (LUSC). Methods  The mRNA expression profiles and clinical data of LUSC patients were downloaded. LUSC-related essential differentially expressed genes were integrated for further analysis. Prognostic gene signatures were identified through random forest regression and univariate Cox regression analyses for constructing a prognostic model. Finally, in a preliminary experiment, we used the reverse transcription-quantitative polymerase chain reaction assay to verify the relationship between the expression of three prognostic gene features and ferroptosis. Results  Fifty-six ferroptosis-related essential genes were identified by using integrated analysis. Among these, three prognostic gene signatures (HELLS, POLR2H, and POLE2) were identified, which were positively affected by LUSC prognosis but negatively affected by immune cell infiltration. Significant overexpression of immune checkpoint genes occurred in the high-risk group. In preliminary experiments, we confirmed that the occurrence of ferroptosis can reduce three prognostic gene signature expression. Conclusions  The three ferroptosis-related genes could predict the LUSC prognostic risk of antitumor immunity.

Iron, Ferroptosis, and Head and Neck Cancer

Ferroptosis is an iron-dependent regulatory form of cell death characterized by the accumulation of intracellular reactive oxygen species and lipid peroxidation. It plays a critical role not only in promoting drug resistance in tumors, but also in shaping therapeutic approaches for various malignancies. This review aims to elucidate the relationship between ferroptosis and head and neck cancer treatment by discussing its conceptual framework, mechanism of action, functional aspects, and implications for tumor therapy. In addition, this review consolidates strategies aimed at improving the efficacy of head and neck cancer treatment through modulation of ferroptosis, herein serving as a valuable reference for advancing the treatment landscape for this patient population.

Sorafenib induces ferroptosis by promoting TRIM54-mediated FSP1 ubiquitination and degradation in hepatocellular carcinoma

BACKGROUND

Ferroptosis is a unique form of regulated cell death that provided a new opportunity for cancer therapy. Ferroptosis suppressor protein 1 (FSP1) is a key regulator in the NAD(P)H/FSP1/CoQ10 antioxidant system, which sever as an oxide redox enzyme to scavenge harmful lipid hydroperoxides and escape from ferroptosis in cells. This study aimed to investigate the role of FSP1 on sorafenib-induced ferroptosis and disclosed the underlying mechanisms.

METHODS

Cell viability, malondialdehyde (MDA), glutathione (GSH), and lipid reactive oxygen species levels were assessed using indicated assay kits. The levels of FSP1 and glutathione peroxidase 4 (GPX4) in the patients with HCC were analyzed based on the database. Western blot and quantitative real-time PCR were performed to detect the protein and mRNA expression. Co-immunoprecipitation was applied to detect the interaction between proteins. Tumor xenograft experiments were used to evaluate whether overexpression of FSP1-inhibited sorafenib-induced ferroptosis in vivo.

RESULTS

We verified that sorafenib-induced ferroptosis in HCC. Furthermore, we found that sorafenib decreased the protein level of FSP1, and knockdown FSP1 rendered HCC cells susceptible to sorafenib-induced ferroptosis. Co-immunoprecipitation and ubiquitination assays showed that sorafenib accelerated the TRIM54-mediated FSP1 ubiquitination and degradation. Sorafenib-induced ferroptosis was abrogated by TRIM54 suppression. Mechanically, sorafenib-promoted TRIM54 ubiquitinated and degraded FSP1 by means of the ERK pathway. Moreover, FSP1 enhanced tumor development and decreased HCC cellular susceptibility to sorafenib in vivo.

CONCLUSIONS

Sorafenib facilitated the TRIM54-mediated FSP1 ubiquitination through the ERK pathway, thereby inducing ferroptosis in HCC cells.

The role of novel programmed cell death in head and neck squamous cell carcinoma: from mechanisms to potential therapies

Head and neck squamous cell carcinoma (HNSCC) is a common oral cancer with poor prognosis and for which no targeted therapeutic strategies are currently available. Accumulating evidence has demonstrated that programmed cell death (PCD) is essential in the development of HNSCC as a second messenger. PCD can be categorized into numerous different subroutines: in addition to the two well-known types of apoptosis and autophagy, novel forms of programmed cell death (e.g., necroptosis, pyroptosis, ferroptosis, and NETosis) also serve as key alternatives in tumorigenesis. Cancer cells are not able to avoid all types of cell death simultaneously, since different cell death subroutines follow different regulatory pathways. Herein, we summarize the roles of novel programmed cell death in tumorigenesis and present our interpretations of the molecular mechanisms with a view to the development of further potential therapies.

Exosomal circBBS2 inhibits ferroptosis by targeting miR-494 to activate SLC7A11 signaling in ischemic stroke

Umbilical cord-mesenchymal stem cells (UC-MSCs)-derived exosomes have been considered as an effective treatment for ischemic stroke. CircRNA BBS2 (circBBS2) was demonstrated to be down-regulated in patients with ischemic stroke. However, the role of UC-MSCs-derived exosomal circBBS2 in ischemic stroke and potential mechanisms remain unclear. Hypoxia/reperfusion (H/R)-exposed SH-SY5Y cells and middle cerebral artery occlusion (MCAO)-treated rats were served as in vitro and in vivo models of ischemic stroke. Target gene expression was detected by qRT-PCR. Cell viability was assessed by MTT assay. Ferroptosis was determined by iron, MDA, GSH, and lipid ROS levels. Protein levels were measured by Western blotting. The target relationships among circBBS2, miR-494, and SLC7A11 were validated by RNA-pull down, RIP, and dual-luciferase reporter assays. TTC and HE staining were performed to evaluate cerebral infarction volume and neuropathological changes. circBBS2 was lowly expressed and ferroptosis was triggered in MCAO rats and H/R-stimulated SH-SY5Y cells. UC-MSCs-derived exosomes enhanced cell viability and restrained ferroptosis via increasing circBBS2 expression in SH-SY5Y cells. Mechanistically, circBBS2 sponged miR-494 to enhance the SLC7A11 level. Knockdown of miR-494 or SLC7A11 reversed the effects of silencing circBBS2 or miR-494 on ferroptosis of SH-SY5Y cells, respectively. Furthermore, UC-MSCs-derived exosomes attenuated ischemic stroke in rats via delivering circBBS2 to inhibit ferroptosis. UC-MSCs-derived exosomal circBBS2 enhanced SLC7A11 expression via sponging miR-494, therefore repressing ferroptosis and relieving ischemic stroke. Our findings shed light on a novel mechanism for UC-MSCs-derived exosomes in the treatment of ischemic stroke.

FSP1: a key regulator of ferroptosis

Ferroptosis suppressor protein 1 (FSP1) is one of the main regulatory molecules of ferroptosis. FSP1 functions through the FSP1-coenzyme Q10 (CoQ10)-NAD(P)H axis and the vitamin K redox cycle. FSP1 is regulated by upstream factors, including transcription factors and noncoding RNA (ncRNA), and is subject to epigenetic modifications, which affect the progress of FSP1-related diseases. FSP1 is closely associated with the poor prognosis of malignant tumors and plays an important role in disease treatment. This review aims to provide a comprehensive understanding of the role of FSP1 in ferroptosis regulation by summarizing regulatory pathways, possible mechanisms involving FSP1, and the relationship between FSP1 and disease prognosis and treatment.

Unraveling the Complexity of Regulated Cell Death in Esophageal Cancer: from Underlying Mechanisms to Targeted Therapeutics

Esophageal cancer (EC) is the sixth most common and the seventh most deadly malignancy of the digestive tract, representing a major global health challenge. Despite the availability of multimodal therapeutic strategies, the existing EC treatments continue to yield unsatisfactory results due to their limited efficacy and severe side effects. Recently, knowledge of the subroutines and molecular mechanisms of regulated cell death (RCD) has progressed rapidly, enhancing the understanding of key pathways related to the occurrence, progression, and treatment of many types of tumors, including EC. In this context, the use of small-molecule compounds to target such RCD subroutines has emerged as a promising therapeutic strategy for patients with EC. Thus, in this review, we firstly discussed the risk factors and prevention of EC. We then outlined the established treatment regimens for patients with EC. Furthermore, we not only briefly summarized the mechanisms of five best studied subroutines of RCD related to EC, including apoptosis, ferroptosis, pyroptosis, necroptosis and autophagy, but also outlined the recent advances in the development of small-molecule compounds and long non-coding RNA (lncRNA) targeting the abovementioned RCD subroutines, which may serve as a new therapeutic strategy for patients with EC in the future.

Role of ferroptosis in esophageal cancer and corresponding immunotherapy

Esophageal cancer (EC) is one of the most common digestive system malignancies in the world. The combined modality treatment of EC is usually surgery and radiation therapy, however, its clinical efficacy for advanced patients is relatively limited. Ferroptosis, a new type of iron-dependent programmed cell death, is different from apoptosis, necrosis and autophagy. In recent years, many studies have further enlightened that ferroptosis plays an essential role in the occurrence, development and metastasis of tumors. Targeting ferroptosis stimulates a new direction for further exploration of oncologic treatment regimens. Furthermore, ferroptosis has a critical role in the immune microenvironment of tumors. This paper reviews the mechanism of ferroptosis and the ferroptosis research progress in the treatment of EC. We further elaborate the interaction between ferroptosis and immunotherapy, and the related mechanisms of ferroptosis participation in the immunotherapy of EC, so as to provide new directions and ideas for the treatment of EC.

Discovery of Novel Potent Covalent Glutathione Peroxidase 4 Inhibitors as Highly Selective Ferroptosis Inducers for the Treatment of Triple-Negative Breast Cancer

Glutathione peroxidase 4 (GPX4) is a promising target to induce ferroptosis for the treatment of triple-negative breast cancer (TNBC). We designed and synthesized a novel series of covalent GPX4 inhibitors based on RSL3 and ML162 by structural integration and simplification strategies. Among them, compound C18 revealed a remarkable inhibitory activity against TNBC cells and significantly inhibited the activity of GPX4 compared to RSL3 and ML162. Moreover, it was identified that C18 could notably induce ferroptosis with high selectivity by increasing the accumulation of lipid peroxides (LPOs) in cells. Further study demonstrated that C18 covalently bound to the Sec46 of GPX4. Surprisingly, C18 exhibited an outstanding potency of tumor growth inhibition in the MDA-MB-231 xenograft model with a TGI value of 81.0%@20 mg/kg without obvious toxicity. Overall, C18 could be a promising GPX4 covalent inhibitor to induce ferroptosis for the treatment of TNBC.

SPINK2 Protein Expression Is an Independent Adverse Prognostic Marker in AML and Is Potentially Implicated in the Regulation of Ferroptosis and Immune Response

There is an urgent need for the identification as well as clinicopathological and functional characterization of potent prognostic biomarkers and therapeutic targets in acute myeloid leukemia (AML). Using immunohistochemistry and next-generation sequencing, we investigated the protein expression as well as clinicopathological and prognostic associations of serine protease inhibitor Kazal type 2 (SPINK2) in AML and examined its potential biological functions. High SPINK2 protein expression was an independent adverse biomarker for survival and an indicator of elevated therapy resistance and relapse risk. SPINK2 expression was associated with AML with an NPM1 mutation and an intermediate risk by cytogenetics and European LeukemiaNet (ELN) 2022 criteria. Furthermore, SPINK2 expression could refine the ELN2022prognostic stratification. Functionally, an RNA sequencing analysis uncovered a potential link of SPINK2 with ferroptosis and immune response. SPINK2 regulated the expression of certain P53 targets and ferroptosis-related genes, including SLC7A11 and STEAP3, and affected cystine uptake, intracellular iron levels and sensitivity to erastin, a specific ferroptosis inducer. Furthermore, SPINK2 inhibition consistently increased the expression of ALCAM, an immune response enhancer and promoter of T-cell activity. Additionally, we identified a potential small-molecule inhibitor of SPINK2, which requires further characterization. In summary, high SPINK2 protein expression was a potent adverse prognostic marker in AML and might represent a druggable target.

Deoxynivalenol affects cell metabolism in vivo and inhibits protein synthesis in IPEC-1 cells

Deoxynivalenol is present in forage crops in concentrations that endanger animal welfare but is also found in cereal-based food. The amphipathic nature of mycotoxins allows them to cross the cell membrane and interacts with different cell organelles such as mitochondria and ribosomes. In our study, we investigated the gene expression of several genes in vivo and in vitro that are related to the metabolism. We observed a significantly higher COX5B and MHCII expression in enterocytes of DON-fed pigs compared to CON-fed pigs and a marked increase in GAPDH and SLC7A11 in DON-fed pigs, but we could not confirm this in vitro in IPEC-1. In vitro, functional metabolic analyses were performed with a seahorse analyzer. A significant increase of non-mitochondrial respiration was observed in all DON-treatment groups (50-2000 ng/mL). The oxygen consumption of cells, which were cultured on membranes, was examined with a fiber-glass electrode. Here, we found significantly lower values for DON 200- and DON 2000-treatment group. The effect on ribosomes was investigated using biorthogonal non-canonical amino acid tagging (BONCAT) to tag newly synthesized proteins. A significantly reduced amount was found in almost all DON-treatment groups. Our findings clearly show that apical and basolateral DON-treatment of epithelial cell layer results in decreasing amounts of newly synthesized proteins. Furthermore, our study shows that DON affects enterocyte metabolism in vivo and in vitro.

Upregulation of the ferroptosis-related STEAP3 gene is a specific predictor of poor triple-negative breast cancer patient outcomes

Objective

This study was designed to assess ferroptosis regulator gene (FRG) expression patterns in patients with TNBC based on data derived from The Cancer Genome Atlas (TCGA). Further, it was utilized to establish a TNBC FRG signature, after which the association between this signature and the tumor immune microenvironment (TIME) composition was assessed, and relevant prognostic factors were explored.

Methods

The TCGA database was used to obtain RNA expression datasets and clinical information about 190 TNBC patients, after which a prognostic TNBC-related FRG signature was established using a least absolute shrinkage and selection operator (LASSO) Cox regression approach. These results were validated with separate data from the Gene Expression Omnibus (GEO). The TNBC-specific prognostic gene was identified via this method. The STEAP3 was then validated through Western immunoblotting, immunohistochemical staining, and quantitative real‐time polymerase chain reaction (RT-qPCR) analyses of clinical tissue samples and TNBC cell lines. Chemotherapy interactions and predicted drug sensitivity studies were investigated to learn more about the potential clinical relevance of these observations.

Results

These data revealed that 87 FRGs were differentially expressed when comparing TNBC tumors and healthy tissue samples (87/259, 33.59%). Seven of these genes (CA9, CISD1, STEAP3, HMOX1, DUSP1, TAZ, HBA1) are significantly related to the overall survival of TNBC patients. Kaplan-Meier analyses and established FRG signatures and nomograms identified CISD1 and STEAP3 genes of prognostic relevance. Prognostic Risk Score values were positively correlated with the infiltration of CD4+ T cells (p = 0.001) and myeloid dendritic cells (p =0.004). Further evidence showed that STEAP3 was strongly and specifically associated with TNBC patient OS (P<0.05). The results above were confirmed by additional examinations of STEAP3 expression changes in TNBC patient samples and cell lines. High STEAP3 levels were negatively correlated with half-maximal inhibitory concentration (IC50) values for GSK1904529A (IGF1R inhibitor), AS601245 (JNK inhibitor), XMD8−85 (Erk5 inhibitor), Gefitinib, Sorafenib, and 5-Fluorouracil (P < 0.05) in patients with TNBC based on information derived from the TCGA-TNBC dataset.

Conclusion

In the present study, a novel FRG model was developed and used to forecast the prognosis of TNBC patients accurately. Furthermore, it was discovered that STEAP3 was highly overexpressed in people with TNBC and associated with overall survival rates, laying the groundwork for the eventually targeted therapy of individuals with this form of cancer.

Overexpression of ferroptosis-related genes FSP1 and CISD1 is related to prognosis and tumor immune infiltration in gastric cancer

PURPOSE

Gastric cancer (GC) is one of the highest incidence rate cancers worldwide and the search for new biomarkers remains urgent due to its relatively poor prognosis and limited treatment methods. Ferroptosis suppressor protein 1 (FSP1) and iron sulfur domain 1 (CISD1) promoted malignant tumor progression as ferroptosis suppressors in a variety of tumors, but their study in GC remains to be explored.

METHODS

In our study, FSP1 and CISD1 expression were predicted through different databases and confirmed by qRT-PCR, immunohistochemistry and western blotting. Enrichment analyses were exploited to explore the potential functions of FSP1 and CISD1. Finally, their relationship with immune infiltration was determined by Tumor Immune Estimation Resource and ssGSEA algorithm.

RESULTS

The expression of FSP1 and CISD1 was higher in GC tissues. Their strongly positive immunostaining was associated with increased tumor size, degree of differentiation, depth of invasion and lymph node metastasis in GC patients. Up-regulated FSP1 and CISD1 predicted poorer overall survival of patients with GC. Furthermore, FSP1 and CISD1 as ferroptosis inhibitors were predicted to be involved in GC immune cell infiltration.

CONCLUSIONS

Our study suggested that FSP1 and CISD1 acted as biomarkers of poor prognosis and promising immunotherapeutic targets for GC.

Curcumin and Andrographis Exhibit Anti-Tumor Effects in Colorectal Cancer via Activation of Ferroptosis and Dual Suppression of Glutathione Peroxidase-4 and Ferroptosis Suppressor Protein-1

Colorectal cancer (CRC) is the leading cause of cancer-related deaths worldwide. The limitations of current chemotherapeutic drugs in CRC include their toxicity, side effects, and exorbitant costs. To assess these unmet needs in CRC treatment, several naturally occurring compounds, including curcumin and andrographis, have gained increasing attention due to their multi-targeted functionality and safety vs. conventional drugs. In the current study, we revealed that a combination of curcumin and andrographis exhibited superior anti-tumor effects by inhibiting cell proliferation, invasion, colony formation, and inducing apoptosis. Genome-wide transcriptomic expression profiling analysis revealed that curcumin and andrographis activated the ferroptosis pathway. Moreover, we confirmed the gene and protein expression of glutathione peroxidase 4 (GPX-4) and ferroptosis suppressor protein 1 (FSP-1), the two major negative regulators of ferroptosis, were downregulated by this combined treatment. With this regimen, we also observed that intracellular accumulation of reactive oxygen species and lipid peroxides were induced in CRC cells. These cell line findings were validated in patient-derived organoids. In conclusion, our study revealed that combined treatment with curcumin and andrographis exhibited anti-tumorigenic effects in CRC cells through activation of ferroptosis and by dual suppression of GPX-4 and FSP-1, which have significant potential implications for the adjunctive treatment of CRC patients.

GPX4: The hub of lipid oxidation, ferroptosis, disease and treatment

Glutathione peroxidase 4 (GPx4) moonlights as structural protein and antioxidase that powerfully inhibits lipid oxidation. In the past years, it is considered as a key regulator of ferroptosis, which takes role in the lipid and amine acid metabolism and influences the cell aging, oncogenesis, and cell death. More and more evidences show that targeting GPX4-induced ferroptosis is a promising strategy for disease therapy, especially cancer treatment. In view of these, we generalize the function of GPX4 and regulatory mechanism between GPX4 and ferroptosis, discuss its roles in the disease pathology, and focus on the recent advances of disease therapeutic potential.

Potential upstream lncRNA-miRNA-mRNA regulatory network of the ferroptosis-related gene SLC7A11 in renal cell carcinoma

Background

SLC7A11 is a key regulator of ferroptosis, which mediates cysteine uptake for glutathione biosynthesis and maintains redox homeostasis. Emerging evidence has shown that SLC7A11 is upregulated in many human tumors. Nevertheless, the prognosis and posttranslational regulatory mechanism of SLC7A11 in renal cell carcinoma (RCC) remains obscure.

Methods

The Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), and The Cancer Genome Atlas (TCGA) databases were used to analyze the difference in SLC7A11 expression between malignant and normal tissues. Furthermore, the GEPIA, the University of ALabama at Birmingham CANcer data analysis Portal (UALCAN), and starBase databases were used to conduct the survival analyses. For correlation analysis, the UALCAN and starBase databases were employed. The Tumor Immune Estimation Resource (TIMER) database was used to approximate the abundance of immune infiltration.

Results

We confirmed that SLC7A11 was upregulated in most human cancers, including 3 types of RCC. SLC7A11 overexpression was linked to poor prognosis of individuals with kidney renal clear cell carcinoma (KIRC), kidney chromophobe cell carcinoma (KICH), and kidney renal papillary cell carcinoma (KIRP). SLC7A11 expression was also linked to immune cell infiltration levels. After performing a comprehensive analysis of the regulatory mechanisms of SLC7A11 expression, the results depicted a potential noncoding (ncRNA)-messenger RNA (mRNA) axis, incorporating SNHG6-miR-26a-5p-SLC7A11 networks in KICH, CASC19/CYTOR/LINC00997-miR-27b-3pSLC7A11 networks in KIRC, and CASC19/CYTOR/PVT1-miR27b-3p-SLC7A11 networks in KIRP as partially responsible for the functions of SLC7A11 in RCC. SLC7A11 expression was positively linked to infiltrated immune cells and their matching marker sets in 3 types of RCC, including CD8⁺ and myeloid dendritic cells.

Conclusions

Our research elucidated the crucial functions and the upstream long noncoding RNA (lncRNA)-microRNA (miRNA) regulatory network of SLC7A11 in RCC. Importantly, SLC7A11 can be used as a potential prognostic biomarker for 3 types of RCC and to determine the infiltration of immune cells in malignant tissues.

Erk1/2-Dependent HNSCC Cell Susceptibility to Erastin-Induced Ferroptosis

Unfavorable clinical outcomes mean that cancer researchers must attempt to develop novel therapeutic strategies to overcome therapeutic resistance in patients with HNSCC. Recently, ferroptosis was shown to be a promising pathway possessing druggable targets, such as xCT (SLC7A11). Unfortunately, little is known about the molecular mechanisms underlying the susceptibility of HNSCC cells to ferroptosis. The goal of this study was to determine whether HNSCC cells with activated Erk1/2 are vulnerable to ferroptosis induction. Our results have shown that xCT (SLC7A11) was overexpressed in malignant tissues obtained from the patients with HNSCC, whereas normal mucosa demonstrated weak expression of the protein. In order to investigate the role of Erk1/2 in the decrease in cell viability caused by erastin, xCT-overexpressing FaDu and SCC25 HNSCC cells were used. The ravoxertinib-dependent inhibition of Erk1/2 signaling led to the decrease in erastin efficacy due to the effect on ROS production and the upregulation of ROS scavengers SOD1 and SOD2, resulting in repressed lipid peroxidation. Therefore, it was concluded that the erastin-dependent activation of ferroptosis seems to be a promising approach which can be further developed as an additional strategy for the treatment of HNSCC. As ferroptosis induction via erastin is strongly dependent on the expression of Erk1/2, this MAP kinase can be considered as a predictor for cancer cells' response to erastin.

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.

Rethinking glutamine metabolism and the regulation of glutamine addiction by oncogenes in cancer

Glutamine, the most abundant non-essential amino acid in human blood, is crucial for cancer cell growth and cancer progression. Glutamine mainly functions as a carbon and nitrogen source for biosynthesis, energy metabolism, and redox homeostasis maintenance in cancer cells. Dysregulated glutamine metabolism is a notable metabolic characteristic of cancer cells. Some carcinogen-driven cancers exhibit a marked dependence on glutamine, also known as glutamine addiction, which has rendered the glutamine metabolic pathway a breakpoint in cancer therapeutics. However, some cancer cells can adapt to the glutamine unavailability by reprogramming metabolism, thus limiting the success of this therapeutic approach. Given the complexity of metabolic networks and the limited impact of inhibiting glutamine metabolism alone, the combination of glutamine metabolism inhibition and other therapeutic methods may outperform corresponding monotherapies in the treatment of cancers. This review summarizes the uptake, transport, and metabolic characteristics of glutamine, as well as the regulation of glutamine dependence by some important oncogenes in various cancers to emphasize the therapeutic potential of targeting glutamine metabolism. Furthermore, we discuss a glutamine metabolic pathway, the glutaminase II pathway, that has been substantially overlooked. Finally, we discuss the applicability of polytherapeutic strategies targeting glutamine metabolism to provide a new perspective on cancer therapeutics.

Emerging Potential Mechanism and Therapeutic Target of Ferroptosis in PDAC: A Promising Future

Pancreatic cancer (PC) is a devastating malignant tumor of gastrointestinal (GI) tumors characterized by late diagnosis, low treatment success and poor prognosis. The most common pathological type of PC is pancreatic ductal adenocarcinoma (PDAC), which accounts for approximately 95% of PC. PDAC is primarily driven by the Kirsten rat sarcoma virus (KRAS) oncogene. Ferroptosis was originally described as ras-dependent cell death but is now defined as a regulated cell death caused by iron accumulation and lipid peroxidation. Recent studies have revealed that ferroptosis plays an important role in the development and therapeutic response of tumors, especially PDAC. As the non-apoptotic cell death, ferroptosis may minimize the emergence of drug resistance for clinical trials of PDAC. This article reviews what has been learned in recent years about the mechanisms of ferroptosis in PDAC, introduces the association between ferroptosis and the KRAS target, and summarizes several potential strategies that are capable of triggering ferroptosis to suppress PDAC progression.

The role of ferroptosis in esophageal cancer

Esophageal cancer is one of the most common cancers with high mortality rate around the world. Although the treatment strategy of this disease has made great progress, the prognosis of advanced patients is not ideal. Ferroptosis, a novel regulatory cell death model, that is different from traditional apoptosis and characterized by increased Fenton reaction mediated by intracellular free iron and lipid peroxidation of cell membrane. Ferroptosis has been proved to be closely linked to a variety of diseases, especially cancer. This review aims to summarize the core mechanism of ferroptosis in esophageal cancer, the regulation of ferroptosis signaling pathway and its current application. At the same time, we emphasize the potential and prospect of ferroptosis in the treatment of esophageal cancer. Collectively, targeting ferroptosis pathway may provide new insights into the diagnosis, treatment and prognosis of esophageal cancer.

The Role of Nonapoptotic Programmed Cell Death — Ferroptosis, Necroptosis, and Pyroptosis — in Pancreatic Ductal Adenocarcinoma Treatment

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal cancer, with a dismal 5-year survival rate of less than 10%. It is estimated that approximately 80% of pancreatic ductal carcinoma (PDAC) patients are diagnosed at an advanced or metastatic stage. Hence, most patients are not appropriate candidates for surgical resection and therefore require systemic chemotherapy. However, it has been reported that most patients develop chemoresistance within several months, partly because of antiapoptotic mechanisms. Hence, inducing alternative programmed cell death (PCD), including ferroptosis, necroptosis or pyroptosis, seems to be a promising strategy to overcome antiapoptosis-mediated chemoresistance. In this review, we shed light on the molecular mechanisms of ferroptosis, necroptosis and pyroptosis and suggest several potential strategies (e.g., compounds and nanoparticles [NPs]) that are capable of triggering nonapoptotic PCD to suppress PDAC progression. In conclusion, these strategies might serve as adjuvants in combination with clinical first-line chemotherapies to improve patient survival rates.

IFNγ enhances ferroptosis by increasing JAK‑STAT pathway activation to suppress SLCA711 expression in adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a rare type of tumor with a poor prognosis. Ferroptosis is a relatively novel form of programmed cell death driven by iron-dependent lipid peroxidation accumulation. Recent evidence suggests that IFNγ facilitates erastin-induced ferroptosis, which contributed to anticancer therapy in various types of cancer. However, it has remained elusive whether the regulation of IFNγ on ferroptosis has a positive role in the treatment of ACC. Thus, the aim of the present study was to explore the effects of IFNγ on erastin-induced ferroptosis in the ACC cell line NCI-H295R and investigate the underlying mechanisms. Cell viability was assessed using a Cell Counting Kit-8 assay, an ethynyldioxyuridine proliferation assay and Live/Dead staining. The levels of iron, reactive oxygen species, lipid peroxidation and mitochondrial damage were also assessed. Western blot and reverse transcription-quantitative PCR analyses were used to determine the underlying molecular mechanisms involved in the erastin-induced ferroptosis of NCI-H295R cells. The results suggested that IFNγ promoted erastin-induced ferroptotic cell death. Furthermore, IFNγ enhanced erastin-induced ferroptosis, as evidenced by the accumulation of iron, as well as the increase in lipid peroxidation and promotion of mitochondrial damage. Further analysis suggested that IFNγ enhanced ferroptosis by suppressing the expression of solute carrier family 7 member 11, an important negative regulator of ferroptosis, and this was achieved via activation of the JAK/STAT pathway in NCI-H295R cells. The present study provided experimental evidence on the activity and mechanism of ferroptosis enhanced by IFNγ in ACC and may give critical insight into the immunotherapeutic management of ACC.

The Role of Cystine/Glutamate Antiporter SLC7A11/xCT in the Pathophysiology of Cancer

SLC7A11/xCT is an antiporter that mediates the uptake of extracellular cystine in exchange for glutamate. Cystine is reduced to cysteine, which is a rate-limiting precursor in glutathione synthesis; a process that protects cells from oxidative stress and is, therefore, critical to cell growth, proliferation, and metabolism. SLC7A11 is expressed in different tissues and plays diverse functional roles in the pathophysiology of various diseases, including cancer, by regulating the processes of redox homeostasis, metabolic flexibility/nutrient dependency, immune system function, and ferroptosis. SLC7A11 expression is associated with poor prognosis and drug resistance in cancer and, therefore, represents an important therapeutic target. In this review, we discuss the molecular functions of SLC7A11 in normal versus diseased tissues, with a special focus on how it regulates gastrointestinal cancers. Further, we summarize current therapeutic strategies targeting SLC7A11 as well as novel avenues for treatment.

Ferroptosis Involvement in Glioblastoma Treatment

Glioblastoma multiforme (GBM) is one of the deadliest brain tumors. Current standard therapy includes tumor resection surgery followed by radiotherapy and chemotherapy. Due to the tumors invasive nature, recurrences are almost a certainty, giving the patients after diagnosis only a 12–15 months average survival time. Therefore, there is a dire need of finding new therapies that could potentially improve patient outcomes. Ferroptosis is a newly described form of cell death with several implications in cancer, among which GBM. Agents that target different molecules involved in ferroptosis and that stimulate this process have been described as potentially adjuvant anti-cancer treatment options. In GBM, ferroptosis stimulation inhibits tumor growth, improves patient survival, and increases the efficacy of radiation and chemotherapy. This review provides an overview of the current knowledge regarding ferroptosis modulation in GBM.

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.

Esophageal Cancer Stem-like Cells Resist Ferroptosis-Induced Cell Death by Active Hsp27-GPX4 Pathway

Cancer stem cells (CSCs), a subpopulation of cancer cells responsible for tumor initiation and treatment failure, are more susceptible to ferroptosis-inducing agents than bulk cancer cells. However, regulatory pathways controlling ferroptosis, which can selectively induce CSC death, are not fully understood. Here, we demonstrate that the CSCs of esophageal squamous carcinoma cells enriched by spheroid culture have increased intracellular iron levels and lipid peroxidation, thereby increasing exposure to several products of lipid peroxidation, such as MDA and 4-HNE. However, CSCs do not reduce cell viability until glutathione is depleted by erastin treatment. Mechanistic studies revealed that damage from elevated lipid peroxidation is avoided through the activation of Hsp27, which upregulates GPX4 and thereby rescues CSCs from ferroptosis-induced cell death. Our results also revealed a correlation between phospho-Hsp27 and GPX4 expression levels and poor prognosis in patients with esophageal cancer. Together, these data indicate that targeting Hsp27 or GPX4 to block this intrinsic protective mechanism against ferroptosis is a potential treatment strategy for eradicating CSC in esophageal squamous cell carcinoma.