Emerging roles of ferroptosis in the tumor immune landscape: from danger signals to anti-tumor immunity

Plant-derived natural compounds: A new frontier in inducing immunogenic cell death for cancer treatment

Immunogenic cell death (ICD) can activate adaptive immune response in the host with normal immune system. Some synthetic chemotherapeutic drugs and natural compounds have shown promising results in cancer treatment by triggering the release of damage-associated molecules (DAMPs) to trigger ICD. However, most chemotherapeutic drugs exhibit non-selective cytotoxicity and may also induce and promote metastasis, thereby significantly reducing their clinical efficacy. Among the natural compounds that can induce ICD, plant-derived compounds account for the largest proportion, which are of increasing value in the treatment of cancer. Understanding which plant-derived natural compounds can induce ICD and how they induce ICD is crucial for developing strategies to improve chemotherapy outcomes. In this review, we focus on the recent findings regarding plant-derived natural compounds that induce ICD according to the classification of flavonoids, alkaloids, glycosides, terpenoids and discuss the potential mechanisms including endoplasmic reticulum (ER) stress, DNA damage, apoptosis, necroptosis autophagy, ferroptosis. In addition, plant-derived natural compounds that can enhance the ICD induction ability of conventional therapies for cancer treatment is also elaborated. The rational use of plant-derived natural compounds to induce ICD is helpful for the development of new cancer treatment methods.

Regulation of gut microbiota on immune cell ferroptosis: A novel insight for immunotherapy against tumor

Gut microbiota contributes to the homeostasis of immune system and is related to various diseases such as tumorigenesis. Ferroptosis, a new type of cell death, is also involved in the disease pathogenesis. Recent studies have found the correlations of gut microbiota mediated ferroptosis and immune cell death. Gut microbiota derived immunosuppressive metabolites, which can promote differentiation and function of immune cells, tend to inhibit ferroptosis through their receptors, whereas inflammatory metabolites from gut microbiota also affect the differentiation and function of immune cells and their ferroptosis. Thus, it is possible for gut microbiota to regulate immune cell ferroptosis. Indeed, gut microbiota metabolite receptor aryl hydrocarbon receptor (AhR) can affect ferroptosis of intestinal intraepithelial lymphocytes, leading to disease pathogenesis. Since immune cell ferroptosis in tumor microenvironment (TME) affects the occurrence and development of tumor, the modulation of gut microbiota in these cell ferroptosis might influence on the tumorigenesis, and also immunotherapy against tumors. Here we will summarize the recent advance of ferroptosis mediated by gut microbiota metabolites, which potentially acts as regulator(s) on immune cells in TME for therapy against tumor.

Ferroptosis and cuproptosis: Metal-dependent cell death pathways activated in response to classical chemotherapy - Significance for cancer treatment?

Apoptosis has traditionally been regarded as the desired cell death pathway activated by chemotherapeutic drugs due to its controlled and non-inflammatory nature. However, recent discoveries of alternative cell death pathways have paved the way for immune-stimulatory treatment approaches in cancer. Ferroptosis (dependent on iron) and cuproptosis (dependent on copper) hold promise for selective cancer cell targeting and overcoming drug resistance. Copper ionophores and iron-bearing nano-drugs show potential for clinical therapy as single agents and as adjuvant treatments. Here we review up-to-date evidence for the involvement of metal ion-dependent cell death pathways in the cytotoxicity of classical chemotherapeutic agents (alkylating agents, topoisomerase inhibitors, antimetabolites, and mitotic spindle inhibitors) and their combinations with cuproptosis and ferroptosis inducers, indicating the prospects, advantages, and obstacles of their use.

Regulation of ferroptosis by nanotechnology for enhanced cancer immunotherapy

INTRODUCTION

This review explores the innovative intersection of ferroptosis, a form of iron-dependent cell death, with cancer immunotherapy. Traditional cancer treatments face limitations in efficacy and specificity. Ferroptosis as a new paradigm in cancer biology, targets metabolic peculiarities of cancer cells and may potentially overcome such limitations, enhancing immunotherapy.

AREA COVERED

This review centers on the regulation of ferroptosis by nanotechnology to augment immunotherapy. It explores how nanoparticle-modulated ferroptotic cancer cells impact the TME and immune responses. The dual role of nanoparticles in modulating immune response through ferroptosis are also discussed. Additionally, it investigates how nanoparticles can be integrated with various immunotherapeutic strategies, to optimize ferroptosis induction and cancer treatment efficacy. The literature search was conducted using PubMed and Google Scholar, covering articles published up to March 2024.

EXPERT OPINION

The manuscript underscores the promising yet intricate landscape of ferroptosis in immunotherapy. It emphasizes the need for a nuanced understanding of ferroptosis' impact on immune cells and the TME to develop more effective cancer treatments, highlighting the potential of nanoparticles in enhancing the efficacy of ferroptosis and immunotherapy. It calls for deeper exploration into the molecular mechanisms and clinical potential of ferroptosis to fully harness its therapeutic benefits in immunotherapy.

DAMP sensing and sterile inflammation: intracellular, intercellular and inter-organ pathways

Damage-associated molecular patterns (DAMPs) are endogenous molecules that are released from host cells as a result of cell death or damage. The release of DAMPs in tissues is associated with loss of tissue homeostasis. Sensing of DAMPs by innate immune receptors triggers inflammation, which can be beneficial in initiating the processes that restore tissue homeostasis but can also drive inflammatory diseases. In recent years, the sensing of intracellular DAMPs has received extensive attention in the field of sterile inflammation. However, emerging studies have shown that DAMPs that originate from neighbouring cells, and even from distal tissues or organs, also mediate sterile inflammatory responses. This multi-level sensing of DAMPs is crucial for intercellular, trans-tissue and trans-organ communication. Here, we summarize how DAMP-sensing receptors detect DAMPs from intracellular, intercellular or distal tissue and organ sources to mediate sterile inflammation. We also discuss the possibility of targeting DAMPs or their corresponding receptors to treat inflammatory diseases.

SLC7A11 inhibits ferroptosis and downregulates PD-L1 levels in lung adenocarcinoma

Introduction

Lung adenocarcinoma (LUAD) is a prevalent form of lung cancer originating from lung glandular cells with low survival rates despite recent therapeutic advances due to its diverse and complex nature. Recent evidence suggests a link between ferroptosis and the effectiveness of anti-PD-L1 therapy, with potential synergistic effects.

Methods

Our study comprehensively analyzed the expression patterns of ferroptosis regulators in LUAD and their association with prognosis and PD-L1 expression. Furthermore, we identified two distinct subtypes of LUAD through consensus clustering of ferroptosis regulators, revealing significant tumor heterogeneity, divergent PD-L1 expression, and varying prognoses between the subtypes.

Results

Among the selected ferroptosis regulators, SLC7A11 emerged as an independent prognostic marker for LUAD patients and exhibited a negative correlation with PD-L1 expression. Subsequent investigations revealed high expression of SLC7A11 in the LUAD population. In vitro experiments demonstrated that overexpression of SLC7A11 led to reduced PD-L1 expression and inhibited ferroptosis in A549 cells, underscoring the significant role of SLC7A11 in LUAD. Additionally, pan-cancer analyses indicated an association between SLC7A11 and the expression of immune checkpoint genes across multiple cancer types with poor prognoses.

Discussion

From a clinical standpoint, these findings offer a foundation for identifying and optimizing potential combination strategies to enhance the therapeutic effectiveness of immune checkpoint inhibitors and improve the prognosis of patients with LUAD.

Non-apoptotic regulated cell death mediates reprogramming of the tumour immune microenvironment by macrophages

Tumour immune microenvironment (TIME) plays an indispensable role in tumour progression, and tumour-associated macrophages (TAMs) are the most abundant immune cells in TIME. Non-apoptotic regulated cell death (RCD) can avoid the influence of tumour apoptosis resistance on anti-tumour immune response. Specifically, autophagy, ferroptosis, pyroptosis and necroptosis mediate the crosstalk between TAMs and tumour cells in TIME, thus reprogram TIME and affect the progress of tumour. In addition, although some achievements have been made in immune checkpoint inhibitors (ICIs), there is still defect that ICIs are only effective for some people because non-apoptotic RCD can bypass the apoptosis resistance of tumour. As a result, ICIs combined with targeting non-apoptotic RCD may be a promising solution. In this paper, the basic molecular mechanism of non-apoptotic RCD, the way in which non-apoptotic RCD mediates crosstalk between TAMs and tumour cells to reprogram TIME, and the latest research progress in targeting non-apoptotic RCD and ICIs are reviewed.

Laser-Ignited Lipid Peroxidation Nanoamplifiers for Strengthening Tumor Photodynamic Therapy Through Aggravating Ferroptotic Propagation and Sustainable High Immunogenicity

Photodynamic therapy (PDT) is extensively investigated for tumor therapy in the clinic. However, the efficacy of PDT is severely limited by the tissue penetrability of light, short effective half-life and radius of reactive oxygen species (ROS), and the weak immunostimulatory effect. In this study, a glutathione (GSH)-activatable nano-photosensitizer is developed to load with arachidonic acid (AA) and camouflage by erythrocyte membrane, which serves as a laser-ignited lipid peroxidation nanoamplifier (MAR). The photosensitive effect of MAR is recovered accompanied by the degradation in the tumor microenvironment and triggers the peroxidation of AA upon laser excitation. Interestingly, it aggravates the propagation of ferroptosis among cancer cells by driving the continuous lipid peroxidation chain reactions with the participation of the degradation products, ferrous ions (Fe2+), and AA. Consequently, even the deep-seated tumor cells without illumination also undergo ferroptosis owing to the propagation of ferroptotic signal. Moreover, the residual tumor cells undergoing ferroptosis still maintain high immunogenicity after PDT, thus continuously triggering sufficient tumor-associated antigens (TAAs) release to remarkably promote the anti-tumor immune response. Therefore, this study will provide a novel "all-in-one" nano-photosensitizer that not only amplifies the damaging effect and expands the effective range of PDT but also improves the immunostimulatory effect after PDT.

Selective induction of programmed cell death using synthetic biology tools

Regulated cell death (RCD) controls the removal of dispensable, infected or malignant cells, and is thus essential for development, homeostasis and immunity of multicellular organisms. Over the last years different forms of RCD have been described (among them apoptosis, necroptosis, pyroptosis and ferroptosis), and the cellular signaling pathways that control their induction and execution have been characterized at the molecular level. It has also become apparent that different forms of RCD differ in their capacity to elicit inflammation or an immune response, and that RCD pathways show a remarkable plasticity. Biochemical and genetic studies revealed that inhibition of a given pathway often results in the activation of back-up cell death mechanisms, highlighting close interconnectivity based on shared signaling components and the assembly of multivalent signaling platforms that can initiate different forms of RCD. Due to this interconnectivity and the pleiotropic effects of 'classical' cell death inducers, it is challenging to study RCD pathways in isolation. This has led to the development of tools based on synthetic biology that allow the targeted induction of RCD using chemogenetic or optogenetic methods. Here we discuss recent advances in the development of such toolset, highlighting their advantages and limitations, and their application for the study of RCD in cells and animals.

Ferroptosis in hepatocellular carcinoma, from mechanism to effect

Hepatocellular carcinoma (HCC) is a prevalent malignant tumor worldwide, characterized by high malignancy and rapid progression. Most cases are diagnosed at intermediate to advanced stages. Current treatment methods have limited efficacy, resulting in high recurrence rates and poor prognosis. Radical hepatectomy remains the primary treatment for HCC, complemented by radiotherapy, chemotherapy, targeted therapy, and immunotherapy. Despite significant improvement in patient prognosis with radical hepatectomy, the five-year survival rate post-surgery remains low; thus necessitating exploration of more effective therapeutic approaches. Ferroptosis is a recently discovered form of cell death that can modulate the occurrence and development of HCC through various mechanisms. This article aims to elucidate the mechanism of ferroptosis and its impact on HCC development to provide novel insights for diagnosis and treatment.

Prognostic Signature Constructed of Seven Ferroptosis-Related lncRNAs Predicts the Prognosis of HBV-Related HCC

BACKGROUND

Ferroptosis and lncRNAs both play crucial roles in cancers. But the roles of ferroptosis-related lncRNAs (FRLncs) in HBV-related HCC (HBV-HCC) remain ambiguous.

METHODS

The gene expression profile and clinical data were originated from the Cancer Genome Atlas (TCGA) database. The risk signature was constructed by FRLncs based on the Cox regression analysis. The survival curve, Cox regression analysis, and time-dependent receiver operating characteristic (ROC) curve were adopted to verify the independence and reliability of the signature. A nomogram was established. Immune-infiltrating cells, immune functions, and checkpoints were analyzed.

RESULTS

A risk signature composed of 7 FRLncs (LINC00942, AC131009.1, POLH-AS1, AC090772.3, MKLN1-AS, AC009403.1, AL031985.3) was constructed and divided HBV-HCC patients into high- and low-risk groups. Patients in the high-risk group showed a poor prognosis. The area under curves (AUC) of the signature for 1-, 3-, and 5-year was satisfactory. A nomogram composed of gender, stage, age, grade, and risk signature was established. The risk signature and nomogram displayed appreciable independence and reliability in HBV-HCC patients. The T-cell CD8 + , monocyte, and macrophage M1 were expressed differently significantly in HCC patients, while macrophage M2 showed an obvious difference in the HBV-HCC patients between the different risk groups. PDCD1 and CTL4 were expressed higher in the high-risk group of HCC patients.

CONCLUSION

A 7-lncRNA signature was identified as a potential prognostic predictor for HBV-HCC patients. Immune therapy may be a promising strategy for HCC patients, especially HBV-HCC patients.

Ferroptosis in immunostimulation and immunosuppression

Ferroptosis is a form of iron-dependent regulated cell death characterized by the accumulation of toxic lipid peroxides, particularly in the plasma membrane, leading to lytic cell death. While it plays a crucial role in maintaining the overall health and proper functioning of multicellular organisms, it can also contribute to tissue damage and pathological conditions. Although ferroptotic damage is generally recognized as an immunostimulatory process associated with the release of damage-associated molecular patterns (DAMPs), the occurrence of ferroptosis in immune cells or the release of immunosuppressive molecules can result in immune tolerance. Consequently, there is ongoing exploration of targeting the upstream signals or the machinery of ferroptosis to therapeutically enhance or inhibit the immune response. In addition to introducing the core molecular mechanisms of ferroptosis, we will focus on the immune characteristics of ferroptosis in pathological conditions, particularly in the context of infection, sterile inflammation, and tumor immunity.

The recent advancements of ferroptosis in the diagnosis, treatment and prognosis of ovarian cancer

Ovarian cancer affects the female reproductive system and is the primary cause of cancer related mortality globally. The imprecise and non-specific nature of ovarian cancer symptoms often results in patients being diagnosed at an advanced stage, with metastatic lesions extending beyond the ovary. This presents a significant clinical challenge and imposes a substantial economic burden on both patients and society. Despite advancements in surgery, chemotherapy, and immunotherapy, the prognosis for most patients with ovarian cancer remains unsatisfactory. Therefore, the development of novel treatment strategies is imperative. Ferroptosis, a distinct form of regulated cell death, characterized by iron-dependent lipid peroxidation, differs from autophagy, apoptosis, and necrosis, and may hold promise as a novel cell death. Numerous studies have demonstrated the involvement of ferroptosis in various conventional signaling pathways and biological processes. Recent investigations have revealed the significant contribution of ferroptosis in the initiation, progression, and metastasis of diverse malignant tumors, including ovarian cancer. Moreover, ferroptosis exhibits a synergistic effect with chemotherapy, radiotherapy, and immunotherapy in restraining the proliferation of ovarian cancer cells. The aforementioned implies that ferroptosis holds considerable importance in the management of ovarian cancer and has the potential to serve as a novel therapeutic target. The present review provides a comprehensive overview of the salient features of ferroptosis, encompassing its underlying mechanisms and functional role in ovarian cancer, along with the associated signaling pathways and genes. Furthermore, the review highlights the prospective utility of ferroptosis in the treatment of ovarian cancer.

The putative role of ferroptosis in gastric cancer: a review

Ferroptosis is a unique cell death modality triggered by iron-dependent lipid peroxidation, with cysteine metabolism and glutathione-dependent antioxidant defence responses as the primary triggering mechanisms. Ferroptosis is an independent tumour suppression mechanism and has been implicated in various disorders. In tumourigenesis, ferroptosis plays a dual role in promoting and inhibiting tumours. P53, NFE2L2, BAP1, HIF, and other tumour suppressor genes regulate ferroptosis, releasing damage-associated molecular patterns or lipid metabolites to influence cellular immune responses. Ferroptosis is also involved in tumour suppression and metabolism. The combination of amino acid, lipid, and iron metabolism is involved in the initiation and execution of ferroptosis, and metabolic regulatory mechanisms also play roles in malignancies. Most investigations into ferroptosis in gastric cancer are concentrated on predictive models, not the underlying processes. This review investigates the underlying mechanisms of ferroptosis, tumour suppressor genes, and the tumour microenvironment.

Role of Non-Coding RNAs in Hepatocellular Carcinoma Progression: From Classic to Novel Clinicopathogenetic Implications

Hepatocellular carcinoma (HCC) is a predominant malignancy with increasing incidences and mortalities worldwide. In Western countries, the progressive affirmation of Non-alcoholic Fatty Liver Disease (NAFLD) as the main chronic liver disorder in which HCC occurrence is appreciable even in non-cirrhotic stages, constitutes a real health emergency. In light of this, a further comprehension of molecular pathways supporting HCC onset and progression represents a current research challenge to achieve more tailored prognostic models and appropriate therapeutic approaches. RNA non-coding transcripts (ncRNAs) are involved in the regulation of several cancer-related processes, including HCC. When dysregulated, these molecules, conventionally classified as "small ncRNAs" (sncRNAs) and "long ncRNAs" (lncRNAs) have been reported to markedly influence HCC-related progression mechanisms. In this review, we describe the main dysregulated ncRNAs and the relative molecular pathways involved in HCC progression, analyzing their implications in certain etiologically related contexts, and their applicability in clinical practice as novel diagnostic, prognostic, and therapeutic tools. Finally, given the growing evidence supporting the immune system response, the oxidative stress-regulated mechanisms, and the gut microbiota composition as relevant emerging elements mutually influencing liver-cancerogenesis processes, we investigate the relationship of ncRNAs with this triad, shedding light on novel pathogenetic frontiers of HCC progression.

Crosstalk between ferroptosis and macrophages: potential value for targeted treatment in diseases

Ferroptosis is a newly identified form of programmed cell death that is connected to iron-dependent lipid peroxidization. It involves a variety of physiological processes involving iron metabolism, lipid metabolism, oxidative stress, and biosynthesis of nicotinamide adenine dinucleotide phosphate, glutathione, and coenzyme Q10. So far, it has been discovered to contribute to the pathological process of many diseases, such as myocardial infarction, acute kidney injury, atherosclerosis, and so on. Macrophages are innate immune system cells that regulate metabolism, phagocytize pathogens and dead cells, mediate inflammatory reactions, promote tissue repair, etc. Emerging evidence shows strong associations between macrophages and ferroptosis, which can provide us with a deeper comprehension of the pathological process of diseases and new targets for the treatments. In this review, we summarized the crosstalk between macrophages and ferroptosis and anatomized the application of this association in disease treatments, both non-neoplastic and neoplastic diseases. In addition, we have also addressed problems that remain to be investigated, in the hope of inspiring novel therapeutic strategies for diseases.

Photo-Enhanced Synergistic Induction of Ferroptosis for Anti-Cancer Immunotherapy

Ferroptosis as programmed cell death received considerable attention in cancer research. Recently, studies have associated ferroptosis with photodynamic therapy (PDT) because PDT promotes glutathione (GSH) deletion, glutathione peroxidase 4 (GPX4) degradation, and lipid peroxide accumulation. However, PDT-induced ferroptosis may be potentially prevented by ferroptosis suppressor protein 1 (FSP1). To address this limitation, herein, a novel strategy is developed to trigger ferroptosis by PDT and FSP1 inhibition. For enhancement of this strategy, a photoresponsive nanocomplex, self-assembled by BODIPY-modified poly(amidoamine) (BMP), is utilized to stably encapsulate the inhibitor of FSP1 (iFSP1) and chlorin e6 (Ce6). The nanosystem promotes intracellular delivery, penetration, and accumulation of ferroptosis inducers in tumors with light irradiation. The nanosystem presents high-performance triggering of ferroptosis and immunogenic cell death (ICD) in vitro and in vivo. Importantly, the nanoparticles increase tumor infiltration of CD8+ T cells and further enhance the efficacy of anti-PD-L1 immunotherapy. The study suggests the potential of photo-enhanced synergistic induction of ferroptosis by the photoresponsive nanocomplexes in cancer immunotherapy.

Ferroptosis: a novel regulated cell death participating in cellular stress response, radiotherapy, and immunotherapy

BACKGROUND

Ferroptosis is a regulated cell death mode triggered by iron-dependent toxic membrane lipid peroxidation. As a novel cell death modality that is morphologically and mechanistically different from other forms of cell death, such as apoptosis and necrosis, ferroptosis has attracted extensive attention due to its association with various diseases. Evidence on ferroptosis as a potential therapeutic strategy has accumulated with the rapid growth of research on targeting ferroptosis for tumor suppression in recent years.

METHODS

We summarize the currently known characteristics and major regulatory mechanisms of ferroptosis and present the role of ferroptosis in cellular stress responses, including ER stress and autophagy. Furthermore, we elucidate the potential applications of ferroptosis in radiotherapy and immunotherapy, which will be beneficial in exploring new strategies for clinical tumor treatment.

RESULT AND CONCLUSION

Based on specific biomarkers and precise patient-specific assessment, targeting ferroptosis has great potential to be translated into practical new approaches for clinical cancer therapy, significantly contributing to the prevention, diagnosis, prognosis, and treatment of cancer.

CA9 knockdown enhanced ionizing radiation-induced ferroptosis and radiosensitivity of hypoxic glioma cells

PURPOSE

Ferroptosis is a type of regulatory cell death, caused by excessive lipid peroxidation This study aimed to explore whether ionizing radiation could induce ferroptosis in glioma cells and whether carbonic anhydrase 9 (CA9) knockdown could enhance the killing effect of ionizing radiation on hypoxic glioma cells through ferroptosis.

MATERIALS AND METHODS

The protein levels of Acyl-CoA Synthetase Long Chain Family Member 4 (ACSL4) were detected by Western blot in glioma cells irradiated by different doses of X-ray. The relative mRNA levels of ferroptosis markers and intracellular iron-associated proteins were detected by Real-time qPCR. Lipid peroxidation of glioma cells was detected by oxidation-sensitive probe C11-BODIPY581/591 staining. CCK-8 Assay was used to detect cell viability after X-ray irradiation. Cloning formation assay was used to assess the radiosensitivity of glioma cells. The exposure of cell surface calreticulin was measured by immunofluorescence staining.

RESULTS

X-ray induced lipid peroxidation and ferroptosis markers expression in U251 and GL261 glioma cells. Knockdown of CA9 in hypoxic glioma cells significantly altered the expression of iron regulation-related proteins and enhanced X-ray-induced ferroptosis and radiosensitivity. The ferroptosis inhibitor significantly improved the survival of cells irradiated by X-ray, while ferroptosis inducers (FINs) enhanced the lethal effect of X-ray on cells. Enhancing ferroptosis in glioma cells promoted the exposure and release of damage-associated molecular patterns (DAMPs).

CONCLUSIONS

Ionizing radiation can induce ferroptosis in glioma cells. CA9 knockdown can enhance the radiosensitivity of hypoxic glioma cells and overcome the resistance of ferroptosis under hypoxia. Enhancing ferroptosis will become a new idea to improve the efficacy of radiotherapy for glioma.

DNA hydrogels and nanogels for diagnostics, therapeutics, and theragnostics of various cancers

As an efficient class of hydrogel-based therapeutic drug delivery systems, deoxyribonucleic acid (DNA) hydrogels (particularly DNA nanogels) have attracted massive attention in the last five years. The main contributor to this is the programmability of these 3-dimensional (3D) scaffolds that creates fundamental effects, especially in treating cancer diseases. Like other active biological ingredients (ABIs), DNA hydrogels can be functionalized with other active agents that play a role in targeting drug delivery and modifying the half-life of the therapeutic cargoes in the body's internal environment. Considering the brilliant advantages of DNA hydrogels, in this survey, we intend to submit an informative collection of feasible methods for the design and preparation of DNA hydrogels and nanogels, and the responsivity of the immune system to these therapeutic cargoes. Moreover, the interactions of DNA hydrogels with cancer biomarkers are discussed in this account. Theragnostic DNA nanogels as an advanced species for both detection and therapeutic purposes are also briefly reviewed.

The current advances of lncRNAs in breast cancer immunobiology research

Breast cancer is the most frequently diagnosed malignancy and the leading cause of cancer-related death in women worldwide. Breast cancer development and progression are mainly associated with tumor-intrinsic alterations in diverse genes and signaling pathways and with tumor-extrinsic dysregulations linked to the tumor immune microenvironment. Significantly, abnormal expression of lncRNAs affects the tumor immune microenvironment characteristics and modulates the behavior of different cancer types, including breast cancer. In this review, we provide the current advances about the role of lncRNAs as tumor-intrinsic and tumor-extrinsic modulators of the antitumoral immune response and the immune microenvironment in breast cancer, as well as lncRNAs which are potential biomarkers of tumor immune microenvironment and clinicopathological characteristics in patients, suggesting that lncRNAs are potential targets for immunotherapy in breast cancer.

Redox Dyshomeostasis with Dual Stimuli-Activatable Dihydroartemisinin Nanoparticles to Potentiate Ferroptotic Therapy of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is highly lethal and resistant to conventional therapies, including chemo-, radio-, and immunotherapy. In this study, it is first determined that a combination of dihydroartemisinin (DHA) and RSL-3 (a glutathione peroxidase 4 (GPX4) inhibitor) markedly induced ferroptosis of PDAC tumor cells. A mechanistic study revealed that DHA can react with iron ions to generate carbon radicals and deplete intracellular glutathione, thereby cumulatively triggering the lipid peroxidation of tumor cells with RSL-3-mediated GPX4 inhibition. A DHA-conjugated amphiphilic copolymer is subsequently synthesized, and intracellular acidity and oxidation dual-responsive DHA nanoparticles are further engineered for the tumor-specific co-delivery of DHA and RSL-3. The resultant nanoparticles (PDBA@RSL-3) efficiently induce ferroptosis of tumor cells in the Panc02 tumor-bearing immune-deficient mouse model, and elicit T-cell-based antitumor immunity in the immune-competent mouse model. The combination of PDBA@RSL-3 nanoparticles and programmed death ligand 1 blockade therapy efficiently inhibits PDAC tumor growth in the immune-competent mouse models. This study may provide novel insights for treatment of PDAC with ferroptosis-based immunotherapy.

Recent Organic Photosensitizer Designs for Evoking Proinflammatory Regulated Cell Death in Antitumor Immunotherapy

In the past decades, immunotherapy has achieved a series of clinical successes in the field of cancer. However, existing therapeutic options usually show a low immune response to solid tumors caused by immunosuppressive "cold" tumor microenvironment (TME). Several types of proinflammatory regulated cell death (RCD), mainly including ferroptosis and pyroptosis, have been studied recently, which can provide proinflammatory signals and immunogenicity necessary for remodeling TME and activating an antitumor immune response. A variety of chemotherapeutic drugs are proven to be effective in the proinflammatory RCD induction of tumor cells, but several adverse effects and intrinsic drug resistance usually occur in the therapeutic process, greatly hindering their further clinical application. The emerging organic photosensitizer (PS)-based materials open new possibilities to effectively activate proinflammatory RCD through precise spatiotemporal regulation of intracellular reactive oxygen species-associated signaling pathways, which can overcome many challenges encountered in current proinflammatory RCD-mediated immunotherapy. In this review, the recent design strategies of PS probes are detailly summarized and their potential advantages for tumor-specific proinflammatory RCD induction are discussed. Moreover, the representative examples in cancer immunotherapy are highlighted and future perspectives in this emerging field are proposed.

Targeting ferroptosis as a cell death pathway in Melanoma: From molecular mechanisms to skin cancer treatment

Melanoma, the most aggressive form of human skin cancer, has been under investigation to reach the most efficient treatment. Surgical resection for early-diagnosed primary melanoma, targeted therapies, and immune checkpoint inhibitors for advanced/metastatic melanoma is the best clinical approach. Ferroptosis, a newly identified iron-dependent cell death pathway, which is morphologically and biochemically different from apoptosis and necrosis, has been reported to be involved in several cancers. Ferroptosis inducers could provide therapeutic options in case of resistance to conventional therapies for advanced/metastatic melanoma. Recently developed ferroptosis inducers, MEK and BRAF inhibitors, miRNAs such as miR-137 and miR-9, and novel strategies for targeting major histocompatibility complex (MHC) class II in melanoma can provide new opportunities for melanoma treatment. Combining ferroptosis inducers with targeted therapies or immune checkpoint inhibitors increases patient response rates. Here we review the mechanisms of ferroptosis and its environmental triggers. We also discuss the pathogenesis and current treatments of melanoma. Moreover, we aim to elucidate the relationship between ferroptosis and melanoma and ferroptosis implications to develop new therapeutic strategies against melanoma.

Bioactive inorganic nanomaterials for cancer theranostics

Bioactive materials are a special class of biomaterials that can react in vivo to induce a biological response or regulate biological functions, thus achieving a better curative effect than traditional inert biomaterials. For cancer theranostics, compared with organic or polymer nanomaterials, inorganic nanomaterials possess unique physical and chemical properties, have stronger mechanical stability on the basis of maintaining certain bioactivity, and are easy to be compounded with various carriers (polymer carriers, biological carriers, etc.), so as to achieve specific antitumor efficacy. After entering the nanoscale, due to the nano-size effect, high specific surface area and special nanostructures, inorganic nanomaterials exhibit unique biological effects, which significantly influence the interaction with biological organisms. Therefore, the research and applications of bioactive inorganic nanomaterials in cancer theranostics have attracted wide attention. In this review, we mainly summarize the recent progress of bioactive inorganic nanomaterials in cancer theranostics, and also introduce the definition, synthesis and modification strategies of bioactive inorganic nanomaterials. Thereafter, the applications of bioactive inorganic nanomaterials in tumor imaging and antitumor therapy, including tumor microenvironment (TME) regulation, catalytic therapy, gas therapy, regulatory cell death and immunotherapy, are discussed. Finally, the biosafety and challenges of bioactive inorganic nanomaterials are also mentioned, and their future development opportunities are prospected. This review highlights the bioapplication of bioactive inorganic nanomaterials.

Ginseng-based carbon dots inhibit the growth of squamous cancer cells by increasing ferroptosis

Background

Recent studies indicated that Ginseng potentiate cancer treatments. Ginseng-based carbon dots (GCDs) might possess properties to kill cancer cells and inhibit malignant tumor development and invasion. This study aimed to prepare GCDs, examine their effects on cancer cell growth and invasion, and explore the mechanisms involved.

Methods

GCDs were synthesized, purified, and characterized. Cells were cultured with GCDs and were tested for growth, invasiveness, and wound healing. RNA was extracted for transcriptomics analysis. Protein expression was evaluated using western blot and immunohistochemistry. Mice were injected with cancer cells and treated with PBS or GCDs. Tumor volume was evaluated.

Results

GCDs were successfully synthesized and purified. The solution was yellow under sunlight and fluorescent blue under ultraviolet light. Electron microscopy showed GCDs with a uniform shape without apparent aggregation and an average diameter of about 4 nm. GCDs inhibited Cal-27, SCC-25, and SCC-7 cancer cell growth at concentrations of >250-300 μg/mL, while GCDs inhibited the non-cancerous HaCaT cells at concentrations >400 μg/mL. Immunofluorescence showed that GCDs could enter the cells. Transcriptomics revealed 552 downregulated mRNAs and 338 upregulated ones, including mRNAs involved in the oxidative phosphorylation and ferroptosis pathways. GCDs induced the ferroptosis of cancer cells, as shown by decreased GPX-4 and increased COX-2. GCDs decreased cell invasion and migration. In vivo, GCDs decreased tumor growth without apparent organ toxicity and promoted CD4+ T cell infiltration in the tumor.

Conclusion

GCDs appear to possess anticancer properties by increasing ferroptosis, resulting in cancer cell growth inhibition in vitro and in vivo.

New Insights into the Role of Ferroptosis in Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the principal cause of disease burden and death worldwide. Ferroptosis is a new form of regulated cell death mainly characterized by altered iron metabolism, increased polyunsaturated fatty acid peroxidation by reactive oxygen species, depletion of glutathione and inactivation of glutathione peroxidase 4. Recently, a series of studies have indicated that ferroptosis is involved in the death of cardiac and vascular cells and has a key impact on the mechanisms leading to CVDs such as ischemic heart disease, ischemia/reperfusion injury, cardiomyopathies, and heart failure. In this article, we reviewed the molecular mechanism of ferroptosis and the current understanding of the pathophysiological role of ferroptosis in ischemic heart disease and in some cardiomyopathies. Moreover, the comprehension of the machinery governing ferroptosis in vascular cells and cardiomyocytes may provide new insights into preventive and therapeutic strategies in CVDs.

Recent advances in ferroptosis and therapeutic strategies for glioblastoma

Ferroptosis is an emerging form of cell death characterized by the over-accumulation of iron-dependent lipid peroxidation. Ferroptosis directly or indirectly disturbs glutathione peroxidases cycle through diverse pathways, impacting the cellular antioxidant capacities, aggravating accumulation of reactive oxygen species in lipid, and it finally causes oxidative overload and cell death. Ferroptosis plays a significant role in the pathophysiological processes of many diseases. Glioblastoma is one of the most common primary malignant brain tumors in the central nervous system in adults. Although there are many treatment plans for it, such as surgical resection, radiotherapy, and chemotherapy, they are currently ineffective and the recurrent rate is almost up to 100%. The therapies abovementioned have a strong relationship with ferroptosis at the cellular and molecular level according to the results reported by numerous researchers. The regulation of ferroptosis can significantly determine the outcome of the cells of glioblastoma. Thus ferroptosis, as a regulated form of programed cell death, has the possibility for treating glioblastoma.

The function of natural compounds in important anticancer mechanisms

The existence of malignant tumors has been a threat to human life, health, and safety. Although the rapid development of radiotherapy, drug therapy, surgery, and local therapy has improved the quality of life of tumor patients, there are still some risks. Natural compounds are widely used in cancer because they are easy to obtain, have a good curative effects and have no obvious side effects, and play a vital role in the prevention and treatment of various cancers. Phenolic, flavonoids, terpenoids, alkaloids, and other natural components of traditional Chinese medicine have certain anti-tumor activities, which can promote apoptosis, anti-proliferation, anti-metastasis, inhibit angiogenesis, change the morphology of cancer cells and regulate immune function, etc., and have positive effects on breast cancer, liver cancer, lung cancer, gastric cancer, rectal cancer and so on. To better understand the effects of natural compounds on cancer, this paper screened out four important pathways closely related to cancer, including cell death and immunogenic cell death, immune cells in the tumor microenvironment, inflammation and related pathways and tumor metastasis, and systematically elaborated the effects of natural compounds on cancer.

Deciphering the potential roles of ferroptosis in regulating tumor immunity and tumor immunotherapy

Cancer immunotherapies, including immune checkpoint inhibition (ICI) and adoptive immune cells therapy, are promising therapeutic strategies. They reactivate the function of immune cells and induce immune responses to attack tumor cells. Although these novel therapies benefited a large amount of cancer patients, many cancer patients have shown fair responses even resistance to cancer immunotherapies, limiting their wide clinical application. Therefore, it is urgent to explore the underlying mechanisms of low response and resistance of cancer immunotherapy to enhance their treatment efficacy. The programmed cell death (PCD) including the ferroptosis, has been demonstrated to play essential roles in antitumor immunity and in regulating the immune response to ICIs. Ferroptosis, a phospholipid peroxidation-mediated, iron-dependent membrane damage, exhibite three critical hallmarks: the oxidation of phospholipids, the lack of lipid peroxide repair capability and the overloading of redox-active iron. Notably, ferroptosis was found to plays important roles in regulating tumor immunity and response to immunotherapy. Therefore, targeting ferroptosis alone or in combination with immunotherapy may provide novel options to promote their antitumor efficacy. However, the effect of ferroptosis on tumor immunity and immunotherapy is affected by the interaction of ferroptosis and cancer cells, immune cells, tumor microenvironment (TME) and others. In this review, we summarized and discussed the critical roles of ferroptosis in regulating antitumor immunity, TME and in the improvement of the therapeutic efficacy of immunotherapy in cancers.

C-MYC Inhibited Ferroptosis and Promoted Immune Evasion in Ovarian Cancer Cells through NCOA4 Mediated Ferritin Autophagy

OBJECTIVE

We aimed to construct the ferritin autophagy regulatory network and illustrate its mechanism in ferroptosis, TME immunity and malignant phenotypes of ovarian cancer.

METHODS

First, we used Western blot assays and immunohistochemistry to detect the pathway expression in ovarian cancer samples (C-MYC, NCOA4). Then, we performed RIP and FISH analysis to verify the targeted binding of these factors after which we constructed ovarian cancer cell models and detected pathway regulator expression (NCOA4). Co-localization and Western blot assays were used to detect ferritin autophagy in different experimental groups. We selected corresponding kits to assess ROS contents in ovarian cancer cells. MMP was measured using flow cytometry and mitochondrial morphology was observed through TEM. Then, we chose Clone, EdU and Transwell to evaluate the proliferation and invasion abilities of ovarian cancer cells. We used Western blot assays to measure the DAMP content in ovarian cancer cell supernatants. Finally, we constructed tumor bearing models to study the effect of the C-MYC pathway on ovarian cancer tumorigenesis and TME immune infiltration in in vivo conditions.

RESULTS

Through pathway expression detection, we confirmed that C-MYC was obviously up-regulated and NCOA4 was obviously down-regulated in ovarian cancer samples, while their expression levels were closely related to the malignancy degree of ovarian cancer. RIP, FISH and cell model detection revealed that C-MYC could down-regulate NCOA4 expression through directly targeted binding with its mRNA. Ferritin autophagy and ferroptosis detection showed that C-MYC could inhibit ferroptosis through NCOA4-mediated ferritin autophagy, thus reducing ROS and inhibiting mitophagy in ovarian cancer cells. Cell function tests showed that C-MYC could promote the proliferation and invasion of ovarian cancer cells through the NCOA4 axis. The Western blot assay revealed that C-MYC could reduce HMGB1 release in ovarian cancer cells through the NCOA4 axis. In vivo experiments showed that C-MYC could promote tumorigenesis and immune evasion in ovarian cancer cells through inhibiting HMGB1 release induced by NCOA4-mediated ferroptosis.

CONCLUSION

According to these results, we concluded that C-MYC could down-regulate NCOA4 expression through directly targeted binding, thus inhibiting ferroptosis and promoting malignant phenotype/immune evasion in ovarian cancer cells through inhibiting ferritin autophagy.

Exogenous 8-hydroxydeoxyguanosine attenuates doxorubicin-induced cardiotoxicity by decreasing pyroptosis in H9c2 cardiomyocytes

Doxorubicin (DOX), which is widely used in cancer treatment, can induce cardiomyopathy. One of the main mechanisms whereby DOX induces cardiotoxicity involves pyroptosis through the NLR family pyrin domain containing 3 (NLRP3) inflammasome and gasdermin D (GSDMD). Increased NAPDH oxidase (NOX) and oxidative stress trigger pyroptosis. Exogenous 8-hydroxydeoxyguanosine (8-OHdG) decreases reactive oxygen species (ROS) production by inactivating NOX. Here, we examined whether 8-OHdG treatment can attenuate DOX-induced pyroptosis in H9c2 cardiomyocytes. Exposure to DOX increased the peroxidative glutathione redox status and NOX1/2/4, toll-like receptor (TLR)2/4, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) expression, while an additional 8-OHdG treatment attenuated these effects. Furthermore, DOX induced higher expression of NLRP3 inflammasome components, including NLRP3, apoptosis-associated speck-like protein containing a c-terminal caspase recruitment domain (ASC), and pro-caspase-1. Moreover, it increased caspase-1 activity, a marker of pyroptosis, and interleukin (IL)-1β expression. All these effects were attenuated by 8-OHdG treatment. In addition, the expression of the cardiotoxicity markers, atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) was increased by DOX, whereas the increase of ANP and BNP induced by DOX treatment was reversed by 8-OHdG. In conclusion, exogenous 8-OHdG attenuated DOX-induced pyroptosis by decreasing the expression of NOX1/2/3, TLR2/4, and NF-κB. Thus, 8-OHdG may attenuate DOX-induced cardiotoxicity through the inhibition of pyroptosis.

Identification and validation of transferrin receptor protein 1 for predicting prognosis and immune infiltration in lower grade glioma

INTRODUCTION

Transferrin receptor protein 1 (TFRC), an ananda molecule associated with ferroptosis, has been identified as affecting a wide spectrum of pathological processes in various cancers, but the prognostic value correlates with the tumor microenvironment of TFRC in lower-grade glioma (LGG) is still unclear.

MATERIALS AND METHODS

Clinical pathological information and gene expression data of patients with LGG come from The Cancer Genome Atlas (TCGA), Chinese Glioma Genome Atlas (CGGA), GTEx, Oncomine, UCSC Xena, and GEO databases. We then used various bioinformatics methods and mathematical models to analyze those data, aiming to investigate the clinical significance of TFRC in LGG and illustrate its association with tumor immunity. In addition, the molecular function and mechanisms of TFRC were revealed by gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and gene set enrichment analysis (GSEA). Immunohistochemical experiments and single-cell analysis have been performed.

RESULTS

TFRC expression was highly expressed in many tumors and showed a poor prognosis. Including gliomas, it was significantly associated with several poor clinical prognostic variables, tumor immune microenvironment, tumor mutational burden (TMB), m6a modification, and ferroptosis in LGG. TFRC as a key factor was further used to build a prediction nomogram. The C-index, calibration curve, and decision curve analysis showed the nomogram was clinically useful and calibration was accurate. At the same time, we also demonstrated that promoter hypomethylation of DNA upstream of TFRC could lead to high TFRC expression and poor overall survival. There is a significant correlation between TFRC and CD8 + T cell, macrophage cell infiltration, and several immune checkpoints, such as PD-L1(cd274), CTLA4, and PD1, suggesting a novel direction for future clinical application. Functional and molecular mechanism analysis showed an association of TFRC expression with immune-related pathways through GSEA, GO, and KEGG analysis. Finally, immunohistochemical experiments and single-cell analysis confirmed the expression of TFRC in glioma.

CONCLUSION

TFRC may be a potential prognostic biomarker and an immunotherapeutic target for glioma.

Enhanced natural killer cell anti-tumor activity with nanoparticles mediated ferroptosis and potential therapeutic application in prostate cancer

Ferroptosis provides an opportunity to overcome the cancer cell therapeutic resistance and modulate the immune system. Here an interaction between ferroptosis of cancer cells and natural killer (NK) cells was investigated with a clinical grade iron oxide nanoparticle (ferumoxytol) for potential synergistic anti-cancer effect of ferroptosis and NK cell therapy in prostate cancer. When ferumoxytol mediated ferroptosis of cancer cells was combined with NK cells, the NK cells' cytotoxic function was increased. Observed ferroptosis mediated NK cell activation was also confirmed with IFN-γ secretion and lytic degranulation. Upregulation of ULBPs, which is one of the ligands for NK cell activating receptor NKG2D, was observed in the co-treatment of ferumoxytol mediated ferroptosis and NK cells. Additionally, HMGB1 and PD-L1 expression of cancer cells were observed in the treatment of ferroptosis + NK cells. Finally, in vivo therapeutic efficacy of ferumoxytol mediated ferroptosis and NK cell therapy was observed with significant tumor volume regression in a prostate cancer mice model. These results suggest that the NK cells' function can be enhanced with ferumoxytol mediated ferroptosis.

Immunogenic cell death related risk model to delineate ferroptosis pathway and predict immunotherapy response of patients with GBM

Immunogenic cell death (ICD) is a type of cell death that leads to the regulation and activation of the immune response, which is marked by the exposure and delivery of damage‐associated molecular patterns (DAMPs) in the tumor microenvironment. Accumulating evidence has revealed the significance of ICD-related genes in tumor progression and therapeutic response. In this study, we obtained two ICD-related clusters for glioblastoma (GBM) by applying consensus clustering, and further constructed a risk signature on account of the prognostic ICD genes. Based on the risk signature, we found that higher risk scores were associated with worse patient prognosis. Besides, the results illustrated that ferroptosis regulators/markers were highly enriched the high-risk group, and ferroptosis were correlated with cytokine signaling pathway and other immune-related pathways. We also discovered that high-risk scores were correlated to specific immune infiltration patterns and good response to immune checkpoint blockade (ICB) treatment. In conclusion, our study highlights the significance of ICD-related genes as prognostic biomarkers and immune response indicators in GBM. And the risk signature integrating prognostic genes possessed significant potential value to predict the prognosis of patients and the efficacy of ICB treatment.

A novel cuproptosis-related subtypes and gene signature associates with immunophenotype and predicts prognosis accurately in neuroblastoma

Background

Neuroblastoma (NB) is the most frequent solid tumor in pediatrics, which accounts for roughly 15% of cancer-related mortality in children. NB exhibited genetic, morphologic, and clinical heterogeneity, which limited the efficacy of available therapeutic approaches. Recently, a new term 'cuproptosis' has been used to denote a unique biological process triggered by the action of copper. In this instance, selectively inducing copper death is likely to successfully overcome the limitations of conventional anticancer drugs. However, there is still a gap regarding the role of cuproptosis in cancer, especially in pediatric neuroblastoma.

Methods

We characterized the specific expression of cuproptosis-related genes (CRGs) in NB samples based on publicly available mRNA expression profile data. Consensus clustering and Lasso-Cox regression analysis were applied for CRGs in three independent cohorts. ESTIMATE and Xcell algorithm was utilized to visualize TME score and immune cell subpopulations' relative abundances. Tumor Immune Dysfunction and Exclusion (TIDE) score was used to predict tumor response to immune checkpoint inhibitors. To decipher the underlying mechanism, GSVA was applied to explore enriched pathways associated with cuproptosis signature and Connectivity map (CMap) analysis for drug exploration. Finally, qPCR verified the expression levels of risk-genes in NB cell lines. In addition, PDHA1 was screened and further validated by immunofluorescence in human clinical samples and loss-of-function assays.

Results

We initially classified NB patients according to CRGs and identified two cuproptosis-related subtypes that were associated with prognosis and immunophenotype. After this, a cuproptosis-related prognostic model was constructed and validated by LASSO regression in three independent cohorts. This model can accurately predict prognosis, immune infiltration, and immunotherapy responses. These genes also showed differential expression in various characteristic groups of all three datasets and NB cell lines. Loss-of-function experiments indicated that PDHA1 silencing significantly suppressed the proliferation, migration, and invasion, in turn, promoted cell cycle arrest at the S phase and apoptosis of NB cells.

Conclusions

Taken together, this study may shed light on new research areas for NB patients from the cuproptosis perspective.

Establishment of a prognostic ferroptosis- and immune-related long noncoding RNAs profile in kidney renal clear cell carcinoma

Background: Ferroptosis and immunity are novel treatments that target several cancers, including kidney renal clear cell carcinoma (KIRC). Long noncoding RNAs (lncRNAs) are an important class of gene expression regulators that play fundamental roles in the regulation of ferroptosis and immunity. We aimed to identify ferroptosis- and immune-related lncRNAs as biomarkers in patients with KIRC.

Methods: Corresponding data for each patient with KIRC were obtained from The Cancer Genome Atlas (TCGA) database. Univariate and multivariate Cox regression analyses were used to identify candidate biomarkers followed by least absolute shrinkage and selection operator (LASSO) regression analyses, weighted gene coexpression network analysis (WGCANA), and gene set enrichment analysis (GSEA).

Results: Three ferroptosis- and immune-related differentially expressed lncRNAs (FI-DELs) (AC124854.1, LINC02609, and ZNF503-AS2) were markedly and independently correlated with the overall survival (OS) of patients with KIRC. The area under the curve (AUC) value of the prognostic model in the entire group using the three FI-DELs was > 0.70. The sensitivity and specificity of the diagnostic model using the three FI-DELs were 0.8586 and 0.9583, respectively.

Conclusion: The present study found that AC124854.1, LINC02609, and ZNF503-AS2 were considerably and independently correlated with the OS of patients with KIRC, suggesting that the three FI-DELs could be used as prognostic and diagnostic biomarkers for patients with KIRC.

Establishing a prognostic model of ferroptosis- and immune-related signatures in kidney cancer: A study based on TCGA and ICGC databases

Background

Kidney cancer (KC) is one of the most challenging cancers due to its delayed diagnosis and high metastasis rate. The 5-year survival rate of KC patients is less than 11.2%. Therefore, identifying suitable biomarkers to accurately predict KC outcomes is important and urgent.

Methods

Corresponding data for KC patients were obtained from the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA) databases. Systems biology/bioinformatics/computational approaches were used to identify suitable biomarkers for predicting the outcome and immune landscapes of KC patients.

Results

We found two ferroptosis- and immune-related differentially expressed genes (FI-DEGs) (Klotho (KL) and Sortilin 1 (SORT1)) independently correlated with the overall survival of KC patients. The area under the curve (AUC) values of the prognosis model using these two FI-DEGs exceeded 0.60 in the training, validation, and entire groups. The AUC value of the 1-year receiver operating characteristic (ROC) curve reached 0.70 in all the groups.

Conclusions

Our present study indicated that KL and SORT1 could be prognostic biomarkers for KC patients. Whether this model can be used in clinical settings requires further validation.

Ferroptosis Inducer Improves the Efficacy of Oncolytic Virus-Mediated Cancer Immunotherapy

Ferroptosis is a type of programmed cell death dependent on iron and characterized by the accumulation of lipid peroxides. In this study, we explore the combination of a ferroptosis activator with an oncolytic vaccinia virus in tumor models. Erastin induced cell death in hepatoma, colon, and ovarian cancer cells, but not in melanoma cancer cells. Erastin, not the oncolytic vaccinia virus (OVV), induced the expression of key marker genes for ferroptosis in cancer cells. In hepatocellular carcinoma and colon cancer models, either erastin or OVV inhibited tumor growth, but a combination of the two yielded the best therapeutic effects, as indicated by inhibited tumor growth or regression and longer host survival. Immunological analyses indicate that erastin alone had little or no effect on systemic immunity or local immunity in the tumor. However, when combined with OV, erastin enhanced the number of activated dendritic cells and the activity of tumor-infiltrating T lymphocytes as indicated by an increase in IFN-γ⁺CD8⁺ and PD-1⁺CD8⁺ T cells. These results demonstrate that erastin can exert cytotoxicity on cancer cells via ferroptosis, but has little effect on immune activity by itself. However, when combined with an OVV, erastin promoted antitumoral immunity and efficacy by increasing the number of activated dendritic cells and promoting the activities of tumor specific CD8⁺ T cells in the tumor.

Construction and Validation of a 6-Ferroptosis Related Gene Signature for Prognosis and Immune Landscape Prediction in Melanoma

Ferroptosis is a newly discovered form of non-apoptotic cell death that relies on iron-mediated oxidative damage, playing a crucial role in the progression and therapy resistance of melanoma. Hence, the potential value of ferroptosis-related genes (FRGs) as a prognostic model and therapeutic target in melanoma requires further investigation. In this study, the relationship between FRGs and melanoma was revealed by analyzing the mRNA expression profiles from The Cancer Genome Atlas (TCGA) and Gene Expression Synthesis (GEO). A 6-FRGs signature was constructed by Univariate, multivariate, and lasso Cox regression analyses in the TCGA cohort. The GEO database was used to validate the efficacy of the signature. The protein and mRNA expression level of the signature genes were examined in real-world melanoma tissues via immunohistochemical and quantificational real-time polymerase chain reaction (qRT-PCR). Functional enrichment analysis and immune-related analysis were conducted to identify the potential biological functions and pathways of the signature. Ten putative small molecule drugs were predicted by Connectivity Map (CMAP). As a result, a 6-FRGs signature was constructed to stratify melanoma patients into two risk groups. Compared with the low-risk group, patients in the high-risk group had a worse prognosis and a lower ImmuneScore. Immune-related pathways were enriched in the low-risk group. Immune Function and immune cell infiltration of the low-risk group were significantly higher than that of the high-risk group. The differential expression of these six FRGs in melanoma and adjacent normal tissues was confirmed. Moreover, higher expression of immune checkpoint molecules and a greater sensitivity to immunotherapy were observed in the low-risk group. Some small molecular drugs in the CMAP database hold the potential to treat melanoma. Overall, we identified a novel FRGs signature for prognostic prediction in melanoma. Based on the signature-related immune infiltration landscape found in our study, targeting the FRGs might be a therapeutic alternative for melanoma.

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

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

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

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

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

Ferroptosis-Related Long Noncoding RNAs as Prognostic Marker for Colon Adenocarcinoma

Background

The incidence of colon adenocarcinoma (COAD) has been increasing over time. Although ferroptosis and long noncoding RNAs (lncRNAs) have been extensively reported to participate in the tumorigenesis and development of COAD, few studies have investigated the role of ferroptosis-related lncRNAs in the prognosis of COAD.

Methods

Gene-sequencing and clinical data for COAD were obtained from The Cancer Genome Atlas database. The coexpression network was constructed using known ferroptosis-related genes. Cox and least absolute shrinkage and selection operator regression were used to screen ferroptosis-related lncRNAs with prognostic value and to identify a predictive model of COAD. Patients with COAD were divided into low- and high-risk groups according to their risk score. Cases of COAD in the International Cancer Genome Consortium database were included as the testing cohort.

Results

In total, nine lncRNAs (LINC02381, AC105219.1, AC009283.1, LINC01011, ELFN1-AS1, EIF3J-DT, NKILA, LINC01063, and SNHG16) were considered prognostic factors for COAD. Then, a risk score model was established. The overall survival rate of COAD patients was negatively associated with the risk score. Kaplan-Meier analyses in the original and testing cohorts showed similar results. The expression of the lncRNAs in tissue was consistent with the risk score, and the relationship with tumor mutation burden, immunity, and drug sensitivity presented a marked link between the signature and COAD. A nomogram was established for clinical applications.

Conclusions

Nine ferroptosis-related lncRNAs and the established signature have a certain predictive value for prognosis of COAD patients and can be used as potential research targets for exploring treatment of COAD.

Construction and Validation of a Ferroptosis-Related Prognostic Signature for Melanoma Based on Single-Cell RNA Sequencing

Melanoma, the deadliest type of skin cancer, is on the rise globally. The generally poor prognosis makes melanoma still an enormous public health problem. Ferroptosis is a newly emerging form of iron-dependent regulated cell death, which has been implicated in the development and treatment of several tumors. However, whether there is a connection between ferroptosis-related genes and the prognosis of melanoma patients remains an enigma. In the present study, we identified a ferroptosis-related genes signature to predict the prognosis of melanoma patients by analyzing single-cell RNA-sequencing data from the Gene Expression Omnibus (GEO). Single-cell trajectory analysis was performed to explore malignant differentiation. CellChat was used to investigate intercellular communications in melanoma. Collectively, a novel four-gene signature (CP, MAP1LC3A, transferrin, and TP53) was constructed for prognosis prediction. COX proportional hazards regression analysis showed that the established ferroptosis-associated risk model was an independent prognostic predictor for melanoma patients (HR = 2.3293; 95%CI 1.1528–4.706) (p < 0.018). Patients with low-risk scores had significantly better overall survival (OS) than those with high-risk scores in The Cancer Genome Atlas, GSE59455, and GSE22153 dataset (p = 0.0015, p = 0.031, p = 0.077). Furthermore, the gene expression level of the four genes were verified in multistrain melanoma cell lines and normal human epidermal melanocytes (NHEM). The protein expression level of the four genes in clinical samples were further verified in the Human Protein Atlas (HPA) databases. Taken together, our study identified the prognostic significance of the ferroptosis-related genes in melanoma and developed a novel four-gene prognostic signature, which may shed light on the prognostic assessment and clinical decision making for melanoma patients.

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

Background

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

Methods

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

Results

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

Conclusion

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

Prognostic Signatures Based on Ferroptosis- and Immune-Related Genes for Cervical Squamous Cell Carcinoma and Endocervical Adenocarcinoma

Cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC) are among the most common malignancies of the female genital tract. Ferroptosis and immunity regulate each other and play important roles in the progression of CESC. The present study aimed to screen ferroptosis- and immune-related differentially expressed genes (FI-DEGs) to identify suitable prognostic signatures for patients with CESC. We downloaded the RNAseq count data and corresponding clinical information of CESC patients from The Cancer Genome Atlas database; obtained recognized ferroptosis- and immune-related genes from the FerrDb and ImmPort databases, respectively; and screened for suitable prognostic signatures using a series of bioinformatics analyses. We identified eight FI-DEGs (CALCRL, CHIT1, DES, DUOX1, FLT1, HELLS, SCD, and SDC1) that were independently correlated with the overall survival of patients with CESC. The prediction model constructed using these eight FI-DEGs was also independently correlated with overall survival. Both the sensitivity and specificity of the prediction model constructed using these eight signatures were over 60%. The comprehensive index of ferroptosis and immune status was significantly correlated with the immunity of patients with CESC. In conclusion, the risk assessment model constructed with these eight FI-DEGs predicted the CESC outcomes. Therefore, these eight FI-DEGs could serve as prognostic signatures for CESC.

Ferroptosis: The Silver Lining of Cancer Therapy

Regulatory cell death has been a major focus area of cancer therapy research to improve conventional clinical cancer treatment (e.g. chemotherapy and radiotherapy). Ferroptosis, a novel form of regulated cell death mediated by iron-dependent lipid peroxidation, has been receiving increasing attention since its discovery in 2012. Owing to the highly iron-dependent physiological properties of cancer cells, targeting ferroptosis is a promising approach in cancer therapy. In this review, we summarised the characteristics of ferroptotic cells, associated mechanisms of ferroptosis occurrence and regulation and application of the ferroptotic pathway in cancer therapy, including the use of ferroptosis in combination with other therapeutic modalities. In addition, we presented the challenges of using ferroptosis in cancer therapy and future perspectives that may provide a basis for further research.

Emerging Pathological Engagement of Ferroptosis in Gut Diseases

Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, is mainly characterized by chronic and progressive inflammation that damages the gastrointestinal mucosa. Increasing studies have enlightened that dysregulated cell death occurs in the inflamed sites, leading to the disruption of the intestinal barrier and aggravating inflammatory response. Ferroptosis, a newly characterized form of regulated cell death, is driven by the lethal accumulation of lipid peroxides catalyzed by cellular free iron. It has been widely documented that the fundamental features of ferroptosis, including iron deposition, GSH exhaustion, GPX4 inactivation, and lipid peroxidation, are manifested in the injured gastrointestinal tract in IBD patients. Furthermore, manipulation of the critical ferroptotic genes could alter the progression, severity, or even morbidity of the experimental colitis. Herein, we critically summarize the recent advances in the field of ferroptosis, focusing on interpreting the potential engagement of ferroptosis in the pathogenesis of IBD. Moreover, we are attempting to shed light on a perspective insight into the possibility of targeting ferroptosis as novel therapeutic designs for the clinical intervention of these gastrointestinal diseases.

Identification of Autophagy- and Ferroptosis-Related lncRNAs Functioned through Immune-Related Pathways in Head and Neck Squamous Carcinoma

The interplay between autophagy and ferroptosis has been highlighted as an important event to decide cancer cell fate. However, the underlying mechanisms remain largely unclear. In this study, we systematically explored the expression, prognostic value and functional roles of lncRNA in autophagy and ferroptosis. By a set of bioinformatics analyses, we identified 363 autophagy- and ferroptosis-related lncRNAs (AF-lncRNAs) and found 17 of them are dramatically related to the prognosis of head and neck squamous cell carcinoma (HNSC) patients, named as prognosis-related AF-lncRNAs (PAF-lncRNAs). Based on six key PAF-lncRNAs, a risk score model was developed and used to categorize the TCGA-retrieved HNSC patients into two groups (high-risk vs. low-risk). Functional analysis showed the differentially expressed genes (DEGs) between the two groups were mainly enriched in immune-related pathways and regulated by a PAF-lncRNA-directed ceRNA (competitive endogenous RNA) network. Combined with a variety of immune infiltration analyses, we also found a decreased landscape of immune cell infiltration in high-risk groups. Together, by revealing PAF-lncRNAs with tumor prognostic features functioned through immune-related pathways, our work would contribute to show the pathogenesis of a lncRNA-directed interplay among autophagy, ferroptosis and tumor immunity in HNSC and to develop potential prognostic biomarkers and targets for tumor immunotherapy.