The Evolving Role of Ferroptosis in Breast Cancer: Translational Implications Present and Future

Ferroptosis as a promising targeted therapy for triple negative breast cancer

PURPOSE

Triple negative breast cancer (TNBC) is a challenging subtype characterized by the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression. Standard treatment options are limited, and approximately 45% of patients develop distant metastasis. Ferroptosis, a regulated form of cell death triggered by iron-dependent lipid peroxidation and oxidative stress, has emerged as a potential targeted therapy for TNBC.

METHODS

This study utilizes a multifaceted approach to investigate the induction of ferroptosis as a therapeutic strategy for TNBC. It explores metabolic alterations, redox imbalance, and oncogenic signaling pathways to understand their roles in inducing ferroptosis, characterized by lipid peroxidation, reactive oxygen species (ROS) generation, and altered cellular morphology. Critical pathways such as Xc-/GSH/GPX4, ACSL4/LPCAT3, and nuclear factor erythroid 2-related factor 2 (NRF2) are examined for their regulatory roles in ferroptosis and their potential dysregulation contributing to cancer cell survival and resistance.

RESULTS

Inhibiting ferroptosis has been shown to inhibit tumor growth, enhance the efficacy of conventional therapies, and overcome drug resistance in TNBC. Lipophilic antioxidants, GPX4 inhibitors, and inhibitors of the Xc- system have been demonstrated to be potential ferroptosis inducers. Additionally, targeting the NRF2 pathway and exploring other ferroptosis regulators, such as ferroptosis suppressor protein 1 (FSP1), and the PERK-eIF2α-ATF4-CHOP pathway, may offer novel therapeutic avenues.

CONCLUSION

Further research is needed to understand the mechanisms, optimize therapeutic strategies, and evaluate the safety and efficacy of ferroptosis-targeted therapies in TNBC treatment. Overall, targeting ferroptosis represents a promising approach to improving treatment outcomes and overcoming the challenges posed by TNBC.

Natural products and the balancing act of autophagy-dependent/independent ferroptosis in cancer therapy

The control of biological cell death is essential for the body's appropriate growth. The resistance of cells to the apoptotic process presents a new difficulty in the treatment of cancer. To combat cancer cells, researchers are working to find new apoptotic pathways and components to activate. One of the processes of regulated cell death (RCD) is referred to as ferroptosis marked by a decline in the activity of lipid glutathione peroxidase 4 (GPX4) after the buildup of reactive oxygen species (ROS). Since lipid peroxidation is a crucial component of ferroptosis and is required for its start, numerous medicines have been studied, particularly for the treatment of cancer. In this context, autophagy is an additional form of RCD that can govern ferroptosis through shared signaling pathways/factors involved in both mechanisms. In this review, we will explore the molecular mechanisms underlying ferroptosis and its association with autophagy, to gain fresh insights into their interplay in cancer advancement, and the potential of natural products for its treatment.

Unraveling the Molecular Regulation of Ferroptosis in Respiratory Diseases

Ferroptosis, a type of programmed cell death that relies on iron, is distinct in terms of its morphological, biochemical and genetic features. Unlike other forms of cell death, such as autophagy, apoptosis, necrosis, and pyroptosis, ferroptosis is primarily caused by lipid peroxidation. Cells that die due to iron can potentially trigger an immune response which intensifies inflammation and causes severe inflammatory reactions that eventually lead to multiple organ failure. In recent years, ferroptosis has been identified in an increasing number of medical fields, including neurological pathologies, chronic liver diseases and sepsis. Ferroptosis has the potential to cause an inflammatory tempest, with many of the catalysts and pathological indications of respiratory ailments being linked to inflammatory reactions. The growing investigation into ferroptosis in respiratory disorders has also garnered significant interest to better understand the mechanism of ferroptosis in these diseases. In this review, the recent progress in understanding the molecular control of ferroptosis and its mechanism in different respiratory disorders is examined. In addition, this review discusses current challenges and prospects for understanding the link between respiratory diseases and ferroptosis.

Tanshinone IIA destabilizes SLC7A11 by regulating PIAS4-mediated SUMOylation of SLC7A11 through KDM1A, and promotes ferroptosis in breast cancer

INTRODUCTION

Breast cancer (BC) is the most common malignancy in women with unfavorite prognosis.

OBJECTIVES

Tanshinone IIA (Tan IIA) inhibits BC progression, however, the underlying mechanism remains largely undefined.

METHODS

The cytotoxicity of Tan IIA was assessed by CCK-8 and LDH assays. Ferroptosis was monitored by the level of MDA, Fe2+, lipid ROS and GSH. IHC and western blot were employed to detect the localization and expression of SLC7A11, PIAS4, KDM1A and other key molecules. The SUMOylation of SLC7A11 was detected by Ni-beads pull-down assay and co-IP. Luciferase and ChIP assays were employed to detect the direct association between KDM1A and PIAS4 promoter. The proliferative and metastatic properties of BC cells were assessed by colony formation, CCK-8 and Transwell assays, respectively. The in vitro findings were verified in xenograft and lung metastasis models.

RESULTS

Tan IIA promoted ferroptosis by suppressing SLC7A11 in BC cells. Silencing of PIAS4 or KDM1A inhibited cell growth and metastasis in BC. Mechanistically, PIAS4 facilitated the SUMOylation of SLC7A11 via direct binding to SLC7A11, and KDM1A acted as a transcriptional activator of PIAS4. Functional studies further revealed that Tan IIA decreased KDM1A expression, thus suppressing PIAS4 expression transcriptionally. The inhibition of PIAS4-dependent SUMOylation of SLC7A11 further induced ferroptosis, thereby inhibiting proliferation and metastasis in BC.

CONCLUSION

Tan IIA promoted ferroptosis and inhibited tumor growth and metastasis via suppressing KDM1A/PIAS4/SLC7A11 axis.

PPARγ alleviates preeclampsia development by regulating lipid metabolism and ferroptosis

The study aims to explore the effect of PPARγ signaling on ferroptosis and preeclampsia (PE) development. Serum and placental tissue are collected from healthy subjects and PE patients. The PPARγ and Nrf2 decreases in the PE. Rosiglitazone intervention reverses hypoxia-induced trophoblast ferroptosis and decreases lipid synthesis by regulating Nfr2 and SREBP1. Compared to the Hypoxia group, the migratory and invasive abilities enhance after rosiglitazone and ferr1 treatment. Rosiglitazone reduces the effect of hypoxia and erastin. The si-Nrf2 treatment attenuats the effects of rosiglitazone on proliferation, migration, and invasion. The si-Nrf2 does not affect SREBP1 expression. PPARγ agonists alleviates ferroptosis in the placenta of the PE rats. The study confirms that PPARγ signaling and ferroptosis-related indicators were dysregulated in PE. PPARγ/Nrf2 signaling affects ferroptosis by regulating lipid oxidation rather than SREBP1-mediated lipid synthesis. In conclusion, our study find that PPARγ can alleviate PE development by regulating lipid oxidation and ferroptosis.

Ferroptosis induction via targeting metabolic alterations in triple-negative breast cancer

Triple-negative breast cancer (TNBC), the most aggressive form of breast cancer, presents severe threats to women's health. Therefore, it is critical to find novel treatment approaches. Ferroptosis, a newly identified form of programmed cell death, is marked by the buildup of lipid reactive oxygen species (ROS) and high iron concentrations. According to previous studies, ferroptosis sensitivity can be controlled by a number of metabolic events in cells, such as amino acid metabolism, iron metabolism, and lipid metabolism. Given that TNBC tumors are rich in iron and lipids, inducing ferroptosis in these tumors is a potential approach for TNBC treatment. Notably, the metabolic adaptability of cancer cells allows them to coordinate an attack on one or more metabolic pathways to initiate ferroptosis, offering a novel perspective to improve the high drug resistance and clinical therapy of TNBC. However, a clear picture of ferroptosis in TNBC still needs to be completely revealed. In this review, we provide an overview of recent advancements regarding the connection between ferroptosis and amino acid, iron, and lipid metabolism in TNBC. We also discuss the probable significance of ferroptosis as an innovative target for chemotherapy, radiotherapy, immunotherapy, nanotherapy and natural product therapy in TNBC, highlighting its therapeutic potential and application prospects.

Ferroptosis: From regulation of lipid peroxidation to the treatment of diseases

Ferroptosis is a regulated cell death mainly manifested by iron-dependent lipid peroxide accumulation. The leading cause of ferroptosis is the imbalance of intracellular oxidative systems (e.g., LOXs, POR, ROS) and antioxidant systems (e.g., GSH/GPx4, CoQ10/FSP1, BH4/GCH1), which is regulated by a complex network. In the past decade, this metabolic network has been continuously refined, and the links with various pathophysiological processes have been gradually established. Apoptosis has been regarded as the only form of regulated cell death for a long time, and the application of chemotherapeutic drugs to induce apoptosis of cancer cells is the mainstream method. However, studies have reported that cancer cells' key features are resistance to apoptosis and chemotherapeutics. For high proliferation, cancer cells often have very active lipid metabolism and iron metabolism, which pave the way for ferroptosis. Interestingly, researchers found that drug-resistant or highly aggressive cancer cells are more prone to ferroptosis. Therefore, ferroptosis may be a potential strategy to eliminate cancer cells. In addition, links between ferroptosis and other diseases, such as neurological disorders and ischemia-reperfusion injury, have also been found. Understanding these diseases from the perspective of ferroptosis may provide new insights into clinical treatment. Herein, the metabolic processes in ferroptosis are reviewed, and the potential mechanisms and targets of ferroptosis in different diseases are summarized.

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.

Iron cycle disruption by heme oxygenase-1 activation leads to a reduced breast cancer cell survival

Heme oxygenase-1 (HO-1), which catalyzes heme degradation releasing iron, regulates several processes related to breast cancer. Iron metabolism deregulation is also connected with several tumor processes. However the regulatory relationship between HO-1 and iron proteins in breast cancer remains unclear. Using human breast cancer biopsies, we found that high HO-1 levels significantly correlated with low DMT1 levels. Contrariwise, high HO-1 levels significantly correlated with high ZIP14 and prohepcidin expression, as well as hemosiderin storage. At mRNA level, we found that high HO-1 expression significantly correlated with low DMT1 expression but high ZIP14, L-ferritin and hepcidin expression. In in vivo experiments in mice with genetic overexpression or pharmacological activation of HO-1, we detected the same expression pattern observed in human biopsies. In in vitro experiments, HO-1 activation induced changes in iron proteins expression leading to an increase of hemosiderin, ROS levels, lipid peroxidation and a decrease of the growth rate. Such low growth rate induced by HO-1 activation was reversed when iron levels or ROS levels were reduced. Our findings demonstrate an important role of HO-1 on iron homeostasis in breast cancer. The changes in iron proteins expression when HO-1 is modulated led to the iron accumulation deregulating the iron cell cycle, and consequently, generating oxidative stress and low viability, all contributing to impair breast cancer progression.

Metformin and long non-coding RNAs in breast cancer

Breast cancer (BC) is the second most common cancer and cause of death in women. In recent years many studies investigated the association of long non-coding RNAs (lncRNAs), as novel genetic factors, on BC risk, survival, clinical and pathological features. Recent studies also investigated the roles of metformin treatment as the firstline treatment for type 2 diabetes (T2D) played in lncRNAs expression/regulation or BC incidence, outcome, mortality and survival, separately. This comprehensive study aimed to review lncRNAs associated with BC features and identify metformin-regulated lncRNAs and their mechanisms of action on BC or other types of cancers. Finally, metformin affects BC by regulating five BC-associated lncRNAs including GAS5, HOTAIR, MALAT1, and H19, by several molecular mechanisms have been described in this review. In addition, metformin action on other types of cancers by regulating ten lncRNAs including AC006160.1, Loc100506691, lncRNA-AF085935, SNHG7, HULC, UCA1, H19, MALAT1, AFAP1-AS1, AC026904.1 is described.

Current insights into the functional roles of ferroptosis in musculoskeletal diseases and therapeutic implications

Ferroptosis is a novel type of cell death associated with iron accumulation and excessive lipid peroxidation. Elucidating the underlying molecular mechanisms of ferroptosis is intensively related to the development and treatment of multiple diseases, including musculoskeletal disorders. Moreover, in vitro and in vivo studies have shown the importance of oxidative stress in musculoskeletal conditions such as osteoporosis, osteoarthritis, rheumatoid arthritis, and osteosarcoma. Ferroptosis-derived clinical management of musculoskeletal diseases offers tremendous and attractive opportunities. Notably, ferroptosis agonists have been proven to enhance the sensitivity of osteosarcoma cells to conventional therapeutic strategies. In this review, we have mainly focused on the implications of ferroptosis regulation in the pathophysiology and therapeutic response of musculoskeletal disorders. Understanding roles of ferroptosis for controlling musculoskeletal diseases might provide directions for ferroptosis-driven therapies, which could be promising for the development of novel therapeutic strategies.

Inducing ferroptosis has the potential to overcome therapy resistance in breast cancer

Breast cancer is the most common type of malignancy among women. Due to the iron-dependent character of breast cancer cells, they are more sensitive to ferroptosis compared to normal cells. It is possible to reverse tumor resistance by inducing ferroptosis in breast cancer cells, thereby improving tumor treatment outcomes. Ferroptosis is highly dependent on the balance of oxidative and antioxidant status. When ferroptosis occurs, intracellular iron levels are significantly increased, leading to increased membrane lipid peroxidation and ultimately triggering ferroptosis. Ferroptotic death is a form of autophagy-associated cell death. Synergistic use of nanoparticle-loaded ferroptosis-inducer with radiotherapy and chemotherapy achieves more significant tumor suppression and inhibits the growth of breast cancer by targeting cancer tissues, enhancing the sensitivity of cells to drugs, reducing the drug resistance of cancer cells and the toxicity of drugs. In this review, we present the current status of breast cancer and the mechanisms of ferroptosis. It is hopeful for us to realize effective treatment of breast cancer through targeted ferroptosis.

Phytochemicals Targeting Ferroptosis: Therapeutic Opportunities and Prospects for Treating Breast Cancer

Ferroptosis, a recently discovered iron-dependent regulated cell death, has been implicated in the therapeutic responses of various cancers including breast cancer, making it a promising therapeutic target to manage this malignancy. Phytochemicals are conventional sources for medication development. Some phytochemicals have been utilized therapeutically to treat cancers as pharmaceutic agents or dietary supplements. Intriguingly, a considerable number of antitumor drugs derived from phytochemicals have been proven to be targeting ferroptosis, thus producing anticancer effects. In this review, we provide a short overview of the interaction between core ferroptosis modulators and breast cancer, illustrating how ferroptosis affects the destiny of breast cancer cells. We also systematically summarize the regulatory effects of phytochemicals on ferroptosis and emphasize their clinical applications in breast cancer suppression, which may accelerate the development of their therapeutic use in breast cancer.

Inhibition of cannabinoid receptor type 1 sensitizes triple-negative breast cancer cells to ferroptosis via regulating fatty acid metabolism

Triple-negative breast cancer (TNBC) is a heterogeneous subtype of breast cancer that displays highly aggressive with poor prognosis. Owing to the limited targets and drugs for TNBC clinical therapy, it is necessary to investigate the factors regulating cancer progression and develop novel therapies for cancer treatment. Ferroptosis, a nonapoptotic form of programmed cell death characterized by accumulation of iron-dependent peroxidation of phospholipids, is regulated by cellular metabolism, redox homeostasis, and various cancer-related signaling pathways. Recently, considerable progress has been made in demonstrating the critical role of lipid metabolism in regulating ferroptosis, indicating potential combinational therapeutic strategies for cancer treatment. In this study, by drug combination screen of lipid metabolism compounds with ferroptosis inducers in decreasing TNBC cell viability, we found potent synergy of the CB1 antagonist rimonabant with erastin/(1 S, 3 R)-RSL3 (RSL3) in inhibiting TNBC cell growth both in vitro and in vivo via promoting the levels of lipid peroxides, malondialdehyde (MDA), 4-hydroxynonenal (4-HNE) and cytosolic reactive oxygen species (ROS) production, enhancing intracellular glutathione (GSH) depletion and inducing G1 cell cycle arrest. We identified that inhibition of CB1 promoted the effect of erastin/RSL3 on inducing ferroptosis and enhanced their inhibitory effect on tumor growth. Using RNA-Seq, fatty acid analyses and functional assays, we found that CB1 regulated stearoyl-CoA desaturase 1 (SCD1)- and fatty acyl desaturase 2 (FADS2)-dependent fatty acid metabolism via phosphatidylinositol 3 kinase (PI3K)-AKT and mitogen-activated protein kinase (MAPK) signaling pathways to modulate ferroptosis sensitivity in TNBC cells. These data demonstrate that dual targeting of CB1 and ferroptosis could be a promising therapeutic strategy for TNBC.

Anti-metastatic breast cancer potential of novel nanocomplexes of diethyldithiocarbamate and green chemically synthesized iron oxide nanoparticles

Mortality rate of metastatic breast cancer is linked to cancer stem cells (CSCs)' aggressive features (chemoresistance to apoptosis and redox imbalance). Therefore, unique dual therapeutic strategy compacts CSCs with inducing oxidative stress-mediated nonapoptosis (ferroptosis), confers effective malignant tumor eradication. Diethyldithiocarbamate (DDC) is a potent inhibitor of CSC aldehyde dehydrogenase and lowers glutathione (GSH) which aggravate iron-dependent ferroptosis. Herein, nanoformulations of DDC with green chemically synthesized ferrous oxide nanoparticles (FeO NPs) and ferric oxide (Fe₂O₃ NPs) were prepared. Due to nanoparticle characters and synergistic effect between iron oxide NPs and DDC, nanocomplexes (DFeO NPs and DFe₂O₃ NPs, respectively) exhibited the strongest anti-metastatic cancer potency in vitro. Because of corresponding iron oxide nature, DFeO NPs demonstrated better therapeutic efficacy than DFe₄O₃ NPs, in mammary tumor liver metastasis-bearing mice, in terms of tumor size, histological analysis, immunostaining % of ki-67⁺ and caspase 3⁺, and gene expression of p53 and BCl2. The potent anti-tumor effect of DFeO nanocomplex is attributed to the maximum elevation of reactive oxygen species and lipid peroxidation (ferroptosis hall marker) with severe depletion of GSH and Nrf2 selectively in both tumor tissues, causing CSC eradication with halting metastatic activity. The latters were confirmed by lowering CD44⁺ % and gene expression of HIF-α, β-catenin, Notch, ABCG2-mediated chemoresistance, and MMP9 with diminishing liver tumor marker. Moreover, this nanocomplex did not cause any abnormal alterations in histological and biochemical parameters, compared to healthy group. Therefore, the selective apoptotic and ferroptotic with anti-CSC effects of DFeO NPs open new safe avenue for metastatic tumor therapy.

Identification of Ferroptosis-Related Prognostic Signature and Subtypes Related to the Immune Microenvironment for Breast Cancer Patients Receiving Neoadjuvant Chemotherapy

Purpose

To identify molecular clusters associated with ferroptosis and to develop a ferroptosis-related signature for providing novel potential targets for the recurrence-free survival and treatment of breast cancer.

Methods

Ferroptosis-related gene (FRG) signature was constructed by univariate and multivariate Cox regression and least absolute shrinkage and selection operator (LASSO). Receiver operating characteristic curves, Kaplan–Meier survival analysis, principal component analysis, and univariate and multivariate Cox regression analyses in the training and test cohorts were used to evaluate the application of this signature. Quantitative reverse transcriptase–PCR (qRT-PCR) was employed to detect the expression of FRGs in the model. Furthermore, the correlations between the signature and immune microenvironment, somatic mutation, and chemotherapeutic drugs sensitivity were explored.

Results

Internal and external validations affirmed that relapse-free survival differed significantly between the high-risk and low-risk groups. Univariate and multivariate Cox regression analyses indicated that the riskScore was an independent prognostic factor for BRCA. The areas under the curve (AUCs) for predicting 1-, 2-, and 3-year survival in the training and test cohorts were satisfactory. Significant differences were also found in the immune microenvironment and IC50 of chemotherapeutic drugs between different risk groups. Furthermore, we divided patients into three clusters based on 18 FRGs to ameliorate the situation of immunotherapy failure in BRCA.

Conclusions

The FRG signature functions as a robust prognostic predictor of the immune microenvironment and therapeutic response, with great potential to guide individualized treatment strategies in the future.

Ferroptosis as a Major Factor and Therapeutic Target for Neuroinflammation in Parkinson's Disease

Mounting evidence suggests that ferroptosis is not just a consequence but also a fundamental contributor to the development and progression of Parkinson’s disease (PD). Ferroptosis is characterized as iron-dependent regulated cell death caused by excessive lipid peroxidation, leading to plasma membrane rupture, release of damage-associated molecular patterns, and neuroinflammation. Due to the crucial role of intracellular iron in mediating the production of reactive oxygen species and the formation of lipid peroxides, ferroptosis is intimately controlled by regulators involved in many aspects of iron metabolism, including iron uptake, storage and export, and by pathways constituting the antioxidant systems. Translational and transcriptional regulation of iron homeostasis and redox status provide an integrated network to determine the sensitivity of ferroptosis. We herein review recent advances related to ferroptosis, ranging from fundamental mechanistic discoveries and cutting-edge preclinical animal studies, to clinical trials in PD and the regulation of neuroinflammation via ferroptosis pathways. Elucidating the roles of ferroptosis in the survival of dopaminergic neurons and microglial activity can enhance our understanding of the pathogenesis of PD and provide opportunities for the development of novel prevention and treatment strategies.