Role of GPX4-Mediated Ferroptosis in the Sensitivity of Triple Negative Breast Cancer Cells to Gefitinib

Combined blockade of GPX4 and activated EGFR/HER3 bypass pathways inhibits the development of ALK-inhibitor-induced tolerant persister cells in ALK-fusion-positive lung cancer

Cancers can develop resistance to treatment with ALK tyrosine kinase inhibitors (ALK-TKIs) via emergence of a subpopulation of drug-tolerant persister (DTP) cells that can survive initial drug treatment long enough to acquire genetic aberrations. DTP cells are thus a potential therapeutic target. We generated alectinib-induced DTP cells from a patient-derived ALK+ non-small-cell lung cancer (NSCLC) cell line and screened 3114 agents in the anticancer compounds library (TargetMol). We identified phospholipid hydroperoxide glutathione peroxidase GPX4 as being involved in promoting the survival of DTP cells. GPX4 was found to be upregulated in DTP cells and to promote cell survival by suppressing reactive oxygen species (ROS) accumulation; GPX4 inhibitors blocked this upregulation and facilitated ROS-mediated cell death. Activated bypass signals involving epidermal growth factor receptor (EGFR)/receptor tyrosine-protein kinase erbB-3 (HER3) were also identified in DTP cells, and co-treatment with EGFR-TKI plus ALK-TKI enhanced ROS levels. Triple combination with an ALK-TKI plus a bypass pathway inhibitor plus a GPX4 inhibitor suppressed cell growth and induced intracellular ROS accumulation more greatly than did treatment with each agent alone. The combined inhibition of ALK plus inhibition of activated bypass signals plus inhibition of GPX4 may be a potent therapeutic strategy for patients with ALK+ NSCLC to prevent the development of resistance to ALK-TKIs and lead to tumor eradication.

Assessment of ferroptosis as a promising candidate for metastatic uveal melanoma treatment and prognostication

Uveal melanoma (UM) is the most common primary intraocular tumour in adults. Local resection, radiation therapy, and enucleation are the current first-line, primary UM treatments. However, regardless of the treatment received, around 50% of UM patients will develop metastatic disease within five to 7 years. In the largest published series of unselected patients with metastatic UM (mUM), the median survival time after diagnosis of metastasis was 3.6 months, with less than 1% of patients surviving beyond 5 years. Approved drugs for treatment of mUM include systemic treatment with tebentafusp-tebn or isolated hepatic perfusion (IHP) with melphalan. However, these drugs are only available to a subset of patients and improve survival by only a few months, highlighting the urgent need for new mUM treatments. Accurately predicting which patients are at high risk for metastases is also crucial. Researchers are developing gene expression signatures in primary UM to create reliable prognostic models aimed at improving patient follow-up and treatment strategies. In this review we discuss the evidence supporting ferroptosis, a non-apoptotic form of cell death, as a potential novel treatment target and prognosticator for UM.

Navigating heme pathways: the breach of heme oxygenase and hemin in breast cancer

Breast cancer remains a significant global health challenge, with diverse subtypes and complex molecular mechanisms underlying its development and progression. This review comprehensively examines recent advances in breast cancer research, with a focus on classification, molecular pathways, and the role of heme oxygenases (HO), heme metabolism implications, and therapeutic innovations. The classification of breast cancer subtypes based on molecular profiling has significantly improved diagnosis and treatment strategies, allowing for tailored approaches to patient care. Molecular studies have elucidated key signaling pathways and biomarkers implicated in breast cancer pathogenesis, shedding light on potential targets for therapeutic intervention. Notably, emerging evidence suggests a critical role for heme oxygenases, particularly HO-1, in breast cancer progression and therapeutic resistance, highlighting the importance of understanding heme metabolism in cancer biology. Furthermore, this review highlights recent advances in breast cancer therapy, including targeted therapies, immunotherapy, and novel drug delivery systems. Understanding the complex interplay between breast cancer subtypes, molecular pathways, and innovative therapeutic approaches is essential for improving patient outcomes and developing more effective treatment strategies in the fight against breast cancer.

Ferroptosis and oral squamous cell carcinoma: connecting the dots to move forward

Oral squamous cell carcinoma (OSCC) is an aggressive disease whose incomplete biological comprehension contributes to the inappropriate clinical management and poor prognosis. Thus, the identification of new promising molecular targets to treat OSCC is of paramount importance. Ferroptosis is a regulated cell death caused by the iron-dependent accumulation of reactive oxygen species and the consequent oxidative damage of lipid membranes. Over the last five years, a growing number of studies has reported that OSCC is sensitive to ferroptosis induction and that ferroptosis inducers exert a remarkable antitumor effect in OSCC, even in those displaying low response to common approaches, such as chemotherapy and radiotherapy. In addition, as ferroptosis is considered an immunogenic cell death, it may modulate the immune response against OSCC. In this review, we summarize the so far identified ferroptosis regulatory mechanisms and prognostic models based on ferroptosis-related genes in OSCC. In addition, we discuss the perspective of inducing ferroptosis as a novel strategy to directly treat OSCC or, alternatively, to improve sensitivity to other approaches. Finally, we integrate data emerging from the research studies, reviewed here, through in silico analysis and we provide a novel personal perspective on the potential interconnection between ferroptosis and autophagy in OSCC.

PCK2 induces gefitinib resistance by suppresses ferroptosis in non-small cell lung cancer

OBJECTIVES

This study aimed to explore the involvement of phosphoenolpyruvate carboxykinase 2 (PCK2) in gefitinib-resistant non-small cell lung cancer (NSCLC) cells and assess its feasibility as a therapeutic target against gefitinib resistance.

METHODS

Gefitinib-resistant cell lines, PC9GR and HCC827GR, were generated through progressive exposure of parental cells to escalating concentrations of gefitinib. Transcriptomic analysis encompassed the treatment of PC9 and PC9GR cells with gefitinib or vehicle, followed by RNA extraction, sequencing, and subsequent bioinformatic analysis. Cell viability was determined via CCK-8 assay, while clonogenic assays assessed colony formation. Apoptosis was detected utilizing the Annexin V-FITC/7AAD kit. Iron ion concentrations were quantified using FerroOrange. mRNA analysis was conducted through quantitative RT-PCR. Western blotting was employed for protein analysis. H&E and immunohistochemical staining were performed on tumor tissue sections.

RESULTS

The results revealed that depletion or inhibition of PCK2 significantly enhanced gefitinib's efficacy in inducing cell growth arrest, apoptosis, and ferroptosis in resistant NSCLC. Moreover, PCK2 knockdown led to the downregulation of key ferroptosis-related proteins, GPX4 and SLC7A11, while upregulating ASCL4. Conversely, overexpression of PCK2 in gefitinib-sensitive cells rendered resistance to gefitinib. In vivo experiments using a gefitinib-resistant xenograft model demonstrated that PCK2 silencing not only reduced tumor growth but also considerably increased the anti-tumor effect of gefitinib.

CONCLUSIONS

In conclusion, our study presents compelling evidence indicating that PCK2 plays a pivotal role in gefitinib resistance in NSCLC. The modulation of ferroptosis-related proteins and the involvement of Akt activation further elucidate the mechanisms underlying this resistance. Consequently, PCK2 emerges as a promising therapeutic target for overcoming gefitinib resistance in NSCLC, offering a new avenue for the development of more effective treatment strategies.

Emerging role of necroptosis, pyroptosis, and ferroptosis in breast cancer: New dawn for overcoming therapy resistance

Breast cancer (BC) is one of the primary causes of death in women worldwide. The challenges associated with adverse outcomes have increased significantly, and the identification of novel therapeutic targets has become increasingly urgent. Regulated cell death (RCD) refers to a type of cell death that can be regulated by several different biomacromolecules, which is distinctive from accidental cell death (ACD). In recent years, apoptosis, a representative RCD pathway, has gained significance as a target for BC medications. However, tumor cells exhibit avoidance of apoptosis and result in treatment resistance, which emphasizes further studies devoted to alternative cell death processes, namely necroptosis, pyroptosis, and ferroptosis. Here, in this review, we focus on summarizing the crucial signaling pathways of these RCD in BC. We further discuss the molecular mechanism and potentiality in clinical application of several prospective drugs, nanoparticles, and other small compounds targeting different RCD subroutines of BC. We also discuss the benefits of modulating RCD processes on drug resistance and the advantages of combining RCD modulators with conventional treatments in BC. This review will deepen our understanding of the relationship between RCD and BC, and shed new light on future directions to attack cancer vulnerabilities with RCD modulators for therapeutic purposes.

Research progress on GPX4 targeted compounds

Blocking the System Xc-_ GSH_GPX4 pathway to induce ferroptosis in tumor cells is a novel strategy for cancer treatment. GPX4 serves as the core of the System Xc-/GSH/GPX4 pathway and is a predominant target for inducing ferroptosis in tumor cells. This article summarizes compounds identified in current research that directly target the GPX4 protein, including inhibitors, activators, small molecule degraders, chimeric degraders, and the application of combination therapies with other drugs, aiming to promote further research on the target and related diseases.

Induction of ferroptosis by brucine suppresses gastric cancer progression through the p53-mediated SLCA711/ALOX12 axis

Increasing evidence indicates important antiproliferative and anti-inflammatory roles of brucine in various diseases. However, the mechanism through which brucine causes the cell death of gastric cancer (GC) remains unclear. In the current research, we looked into whether brucine inhibits GC progression. GC cell migration and proliferation were assessed in response to brucine using Transwell, scratch, and the Cell Counting Kit-8 (CCK-8) assays. To assess the expression of proteins linked to ferroptosis, western blotting was used. An in vivo experiment was conducted to investigate if brucine decreases tumor growth. The CCK-8 experiment demonstrated that brucine reduced AGS and MKN45 cell viability in a way that was dose- and time-dependent. Brucine dramatically promoted cell death in AGS and MKN45 cells according to flow cytometry. In addition, brucine reduced AGS and MKN45 cells' ability to migrate. According to Western blot investigations, brucine elevated p53 and ALOX12 expression, while suppressing the expression of SLC7A11 in AGS and MKN45 cells. Notably, silencing p53 reversed brucine-induced ferroptotic cell death. Additionally, brucine was shown to decrease tumor weight and volume in in vivo experiments. Moreover, malondialdehyde (MDA) and Fe2+ levels decreased in response to brucine treatment. Furthermore, in tumors treated with brucine, p53 and ALOX12 expression increased, whereas SLCA711 expression decreased. In summary, we demonstrated that brucine regulates the p53/SLCA711/ALOX12 axis to cause ferroptosis in GC cells. The results of this study lend support to the idea of treating GC with brucine.

Arenobufagin regulates the p62-Keap1-Nrf2 pathway to induce autophagy-dependent ferroptosis in HepG2 cells

Hepatocellular carcinoma (HCC) is the most prevalent type of primary liver cancer, accounting for the overwhelming majority of malignant liver tumors. Therefore, how to effectively prevent and cure HCC has become a research hotspot. Many studies have shown that arenobufagin can induce apoptosis, ferroptosis, and autophagy of tumor cells. An increasing number of studies have shown that autophagy is closely linked to ferroptosis. In this study, HepG2 cells and BALB/c nude mice were used as research objects to explore the effect and preliminary mechanism of hepatoma cell autophagy and ferroptosis induced by arenobufagin. We found that arenobufagin can significantly inhibit tumor growth in vivo, and interestingly, we found that arenobufagin inhibited ferroptosis-related proteins Nrf2 and COX-2 in a dose-dependent manner and decreased the levels of reduced glutathione (GSH) and superoxide dismutase (T-SOD) in tissues, while increased the level of reduced malondialdehyde (MDA). In addition, we found that arenobufagin increased the levels of COX-2 and MDA in cells, decreased the levels of Nrf2, GSH, and T-SOD, increased the levels of tissue reactive oxygen species (ROS) and lipid ROS in a dose-dependent manner, and promoted ferroptosis in HepG2 cells. HepG2 cells were preprotected by autophagy inhibitor chloroquine (CQ) and ferroptosis inhibitor deferoxamine (DFO), and then treated with arenobufagin. It was found that CQ partially reversed the changes of COX-2 and Nrf2 expression and lipid peroxidation induced by arenobufagin-induced autophagy and HepG2 cells. Interestingly, CQ partially reversed the inhibition of arenobufagin on cytoplasmic junction protein (Keap1) and heme oxygenase-1 (HO-1) in p62-Keap1-Nrf2 pathway. At the same time, we found that the effect of arenobufagin on oxidative stress of HepG2 cells overexpressed by Nrf2 was significantly less than that of the control group. To sum up, arenobufagin promotes autophagy-dependent ferroptosis of HepG2 cells by inducing autophagy and regulating p62-Keap1-Nrf2 pathway. It is suggested that arenobufagin can be used as a potential intervention therapy.

Role of Ferroptosis Regulation by Nrf2/NQO1 Pathway in Alcohol-Induced Cardiotoxicity In Vitro and In Vivo

The aim of the present study was to evaluate the cardiotoxic effects of alcohol and its potential toxic mechanism on ferroptosis in mice and H9c2 cells. Mice were intragastrically treated with three different concentrations of alcohol, 7, 14, and 28%, each day for 14 days. Body weight and electrocardiography (ECG) were recorded over the 14 day period. Serum creatine kinase (CK), lactic dehydrogenase (LDH), MDA, tissue iron, and GSH levels were measured. Cardiac tissues were examined histologically, and ferroptosis was assessed. In H9c2 cardiomyocytes, cell viability, reactive oxygen species (ROS), labile iron pool (LIP), and mitochondrial membrane potential (MMP) were measured. The proteins of ferroptosis were evaluated by the western blot technique in vivo and in vitro. The results showed that serum CK, LDH, MDA, and tissue iron levels significantly increased in the alcohol treatment group in a dose-dependent manner. The content of GSH decreased after alcohol treatment. ECG and histological examinations showed that alcohol impaired cardiac function and structure. In addition, the levels of ROS and LIP increased, and MMP levels decreased after alcohol treatment. Ferrostatin-1 (Fer-1) protected cells from lipid peroxidation. Western blotting analysis showed that alcohol downregulated the expression of Nrf2, NQO1, HO-1, and GPX4. The expressions of P53 and TfR were upregulated in vivo and in vitro. Fer-1 significantly alleviated alcohol-induced ferroptosis. In conclusion, the study showed that Nrf2/NQO1-dependent ferroptosis played a vital role in the cardiotoxicity induced by alcohol.

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

Inducing 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.

Revolutionizing breast cancer treatment: Harnessing the related mechanisms and drugs for regulated cell death (Review)

Breast cancer arises from the malignant transformation of mammary epithelial cells under the influence of various carcinogenic factors, leading to a gradual increase in its prevalence. This disease has become the leading cause of mortality among female malignancies, posing a significant threat to the health of women. The timely identification of breast cancer remains challenging, often resulting in diagnosis at the advanced stages of the disease. Conventional therapeutic approaches, such as surgical excision, chemotherapy and radiotherapy, exhibit limited efficacy in controlling the progression and metastasis of the disease. Regulated cell death (RCD), a process essential for physiological tissue cell renewal, occurs within the body independently of external influences. In the context of cancer, research on RCD primarily focuses on cuproptosis, ferroptosis and pyroptosis. Mounting evidence suggests a marked association between these specific forms of RCD, and the onset and progression of breast cancer. For example, a cuproptosis vector can effectively bind copper ions to induce cuproptosis in breast cancer cells, thereby hindering their proliferation. Additionally, the expression of ferroptosis‑related genes can enhance the sensitivity of breast cancer cells to chemotherapy. Likewise, pyroptosis‑related proteins not only participate in pyroptosis, but also regulate the tumor microenvironment, ultimately leading to the death of breast cancer cells. The present review discusses the unique regulatory mechanisms of cuproptosis, ferroptosis and pyroptosis in breast cancer, and the mechanisms through which they are affected by conventional cancer drugs. Furthermore, it provides a comprehensive overview of the significance of these forms of RCD in modulating the efficacy of chemotherapy and highlights their shared characteristics. This knowledge may provide novel avenues for both clinical interventions and fundamental research in the context of breast cancer.

Deciphering Ferroptosis: From Molecular Pathways to Machine Learning-Guided Therapeutic Innovation

Ferroptosis is a unique form of cell death reliant on iron and lipid peroxidation. It disrupts redox balance, causing cell death by damaging the plasma membrane, with inducers acting through enzymatic pathways or transport systems. In cancer treatment, suppressing ferroptosis or circumventing it holds significant promise. Beyond cancer, ferroptosis affects aging, organs, metabolism, and nervous system. Understanding ferroptosis mechanisms holds promise for uncovering novel therapeutic strategies across a spectrum of diseases. However, detection and regulation of this regulated cell death are still mired with challenges. The dearth of cell, tissue, or organ-specific biomarkers muted the pharmacological use of ferroptosis. This review covers recent studies on ferroptosis, detailing its properties, key genes, metabolic pathways, and regulatory networks, emphasizing the interaction between cellular signaling and ferroptotic cell death. It also summarizes recent findings on ferroptosis inducers, inhibitors, and regulators, highlighting their potential therapeutic applications across diseases. The review addresses challenges in utilizing ferroptosis therapeutically and explores the use of machine learning to uncover complex patterns in ferroptosis-related data, aiding in the discovery of biomarkers, predictive models, and therapeutic targets. Finally, it discusses emerging research areas and the importance of continued investigation to harness the full therapeutic potential of targeting ferroptosis.

G-4 inhibits triple negative breast cancer by inducing cell apoptosis and promoting LCN2-dependent ferroptosis

Compound G-4 is a derivate of cyclin-dependent kinase inhibitor Rocovitine and showed strong sensitivity to triple negative breast cancer (TNBC) cells. In this study, the antitumor activity, mechanism and possible targets of G-4 in TNBC were investigated. Flow cytometry and immunoblotting showed that G-4 not only arrested the S phase of the cell cycle, but also induced apoptosis in TNBC cells via the mitochondrial pathway through inhibiting epidermal growth factor receptor (EGFR), AKT and MAPK pathways. In addition, G-4 induced the iron-mutagenesis process in TNBC cells and down-regulated differentially expressed gene lipid carrier protein 2 (LCN2) by RNA-seq. Moreover, G-4 elevated levels of cytosolic reactive oxygen species (ROS), lipid ROS, Fe and malondialdehyde (MDA), but decreased levels of superoxide dismutase (SOD) and glutathione (GSH), consistent with the effects of iron-mutagenic agonists Erastin and RSL3, which were inhibited by the iron inhibitor ferrostatin-1 (Fer-1). Furthermore, a LCN2 knockdown cell model was established by siRNA transfection, the IC50 of G-4 was increased nearly 100-fold, accompanied by a trend of no ferroptosis characteristic index. The results indicated that G-4 suppressed the malignant phenotype of TNBC, induced apoptosis by inhibiting EGFR pathway and promoted LCN2-dependent ferroptosis.

Excessive fluoride induces ovarian function impairment by regulating levels of ferroptosis in fluorosis women and ovarian granulosa cells

The aim of this study was to investigate the role of ferroptosis in fluorosis women and the in vitro molecular mechanisms leading to ovarian dysfunction and abnormal hormone secretion by sodium fluoride (NaF) treatment of KGN cells. Fifty women with fluorosis as Fluorosis group and fifty healthy women as Control group were included in this study. The levels of lipid peroxidation and activities of antioxidant enzyme were assessed by photometric methods. The content of iron and glutathione (GSH) in serum was measured by microplate method. KGN cells were treated by different concentration of NaF (0, 1, 2, 4 and 8 ×10-3 M) for 24 h. The mRNA and protein expression levels of ferroptosis-related molecules, including glutathione peroxidase 4 (GPX4), solute carrier family 7 member (SLC7A11), nuclear factor erythroid 2-related factor 2 (Nrf2), ferritin heavy chain 1 (FTH1) and p53, were assessed by qRT-PCR and western blot analysis. Fluorosis group women had a significant higher levels of iron, Malondialdehyde (MDA), FSH and LH, and a lower levels of E2 and antioxidant enzyme in serum than that in the control group. The representative molecular changes of ferroptosis, such as the decrease in GPX4, Nrf2 and SLC7A11 expression (mRNA and protein expression), the increase in protein expression of p53, and a reduced level of E2 were observed in KGN cells treated by excessive NaF.It is concluded therefore that NaF increases the expression of p53 and inhibits ovarian granulosa cell ferroptosis preventive protein expression, resulting in abnormal hormone secretion and the ovarian dysfunction.

The role of hepatitis B virus surface protein in inducing Sertoli cell ferroptosis

BACKGROUNDS

Hepatitis B virus infection could result in male infertility with sperm defects and dysfunction. Sertoli cells are essential for testis function and play a crucial role in spermatogenesis. Sertoli cell death contributes to spermatogenesis impairment, leading to poor sperm quality. Ferroptosis has been implicated as a mechanism of Sertoli cell death. The issue in studying the relationship between hepatitis B virus and Sertoli cell ferroptosis has not yet been addressed.

OBJECTIVES

To explore the mechanisms underlying ferroptosis in hepatitis B virus-exposed Sertoli cells.

MATERIALS AND METHODS

Human Sertoli cells were treated in vitro with levels of 25, 50, and 100 μg/mL of hepatitis B virus surface protein (HBs). Cell viability and levels of glutathione, malondialdehyde, cellular ferrous ion (Fe2+ ), lipid peroxidation, and N6-methyladenosine in Sertoli cells were detected. The level of glutathione peroxidase 4, transferrin receptor 1, ferritin heavy chain, tripartite motif (TRIM) 37, methyltransferase like 3, and insulin-like growth factor 2 mRNA binding protein 2 was examined. Cell transfection was carried out to alter expression of ferroptosis-related proteins. qPCR and immunoblotting were performed to measure protein expression level. Immunoprecipitation was applied to determine the protein and protein-RNA interaction. Luminescence analysis was performed to identify the target of methyltransferase like 3.

RESULTS

HBs exposure triggered ferroptosis featured with increased intracellular Fe2+ ion, reduced cell viability and expression of glutathione peroxidase 4 in Sertoli cells. HBs treatment significantly increased TRIM37 expression, which suppressed glutathione peroxidase 4 expression through ubiquitination. TRIM37 silencing attenuated the effect of HBs exposure-regulated cell viability and ferroptosis. HBs upregulated N6-methyladenosine modification in TRIM37 3'-UTR by increasing methyltransferase like 3 expression. The binding of N6-methyladenosine reader insulin-like growth factor 2 mRNA binding protein 2 and TRIM37 3'-UTR enhanced the stability of TRIM37 mRNA.

CONCLUSION

HBs can decrease human Sertoli cell viability by promoting ferroptosis induced by the loss of glutathione peroxidase 4 activity through TRIM37-mediated ubiquitination of glutathione peroxidase 4. The findings highlight the role of TRIM37/glutathione peroxidase 4 signaling responsible for ferroptosis regulation in hepatitis B virus-infected Sertoli cells.

Ferroptosis and EMT resistance in cancer: a comprehensive review of the interplay

Ferroptosis differs from traditional cell death mechanisms like apoptosis, necrosis, and autophagy, primarily due to its reliance on iron metabolism and the loss of glutathione peroxidase activity, leading to lipid peroxidation and cell death. The dysregulation of iron metabolism is a hallmark of various cancers, contributing to tumor progression, metastasis, and notably, drug resistance. The acquisition of mesenchymal characteristics by epithelial cells is known as Epithelial-Mesenchymal Transition (EMT), a biological process intricately linked to cancer development, promoting traits such as invasiveness, metastasis, and resistance to therapeutic interventions. EMT plays a pivotal role in cancer progression and contributes significantly to the complex dynamics of carcinogenesis. Research findings indicate that mesenchymal cancer cells exhibit greater susceptibility to ferroptosis compared to their epithelial counterparts. The induction of ferroptosis becomes more effective in eliminating drug-resistant cancer cells during the process of EMT. The interplay between ferroptosis and EMT, a process where epithelial cells transform into mobile mesenchymal cells, is crucial in understanding cancer progression. EMT is associated with increased cancer metastasis and drug resistance. The review delves into how ferroptosis and EMT influence each other, highlighting the role of key proteins like GPX4, which protects against lipid peroxidation, and its inhibition can induce ferroptosis. Conversely, increased GPX4 expression is linked to heightened resistance to ferroptosis in cancer cells. Moreover, the review discusses the implications of EMT-induced transcription factors such as Snail, Zeb1, and Twist in modulating the sensitivity of tumor cells to ferroptosis, thereby affecting drug resistance and cancer treatment outcomes. Targeting the ferroptosis pathway offers a promising therapeutic strategy, particularly for tumors resistant to conventional treatments. The induction of ferroptosis in these cells could potentially overcome drug resistance. However, translating these findings into clinical practice presents challenges, including understanding the precise mechanisms of ferroptosis induction, identifying predictive biomarkers, and optimizing combination therapies. The review underscores the need for further research to unravel the complex interactions between ferroptosis, EMT, and drug resistance in cancer. This could lead to the development of more effective, targeted cancer treatments, particularly for drug-resistant tumors, offering new hope in cancer therapeutics.

Ferroptosis-Based Therapeutic Strategies toward Precision Medicine for Cancer

Ferroptosis is a type of iron-dependent programmed cell death characterized by the dysregulation of iron metabolism and the accumulation of lipid peroxides. This nonapoptotic mode of cell death is implicated in various physiological and pathological processes. Recent findings have underscored its potential as an innovative strategy for cancer treatment, particularly against recalcitrant malignancies that are resistant to conventional therapies. This article focuses on ferroptosis-based therapeutic strategies for precision cancer treatment, covering the molecular mechanisms of ferroptosis, four major types of ferroptosis inducers and their inhibitory effects on diverse carcinomas, the detection of ferroptosis by fluorescent probes, and their implementation in image-guided therapy. These state-of-the-art tactics have manifested enhanced selectivity and efficacy against malignant carcinomas. Given that the administration of ferroptosis in cancer therapy is still at a burgeoning stage, some major challenges and future perspectives are discussed for the clinical translation of ferroptosis into precision cancer treatment.

Tremella fuciformis polysaccharides induce ferroptosis in Epstein-Barr virus-associated gastric cancer by inactivating NRF2/HO-1 signaling

Approximately 10% of gastric cancers are associated with Epstein-Barr virus (EBV). Tremella fuciformis polysaccharides (TFPs) are characterized by antioxidative and anti-inflammatory effects in different diseases. However, whether TFP improves EBV-associated gastric cancer (EBVaGC) has never been explored. The effects of TFP on EBV-infected GC cell viability were determined using a CCK-8 assay and flow cytometry. Western blotting and RT-qPCR were performed to explore the expression of ferroptosis-related proteins. The CCK-8 assay showed that TFP decreased EBV-infected GC cell viability in a dose- and time-dependent manner. Flow cytometry assays indicated that TFP significantly induced EBV-infected GC cell death. TFP also reduced the migratory capacity of EBV-infected GC cells. Furthermore, treatment with TFP significantly increased the mRNA levels of PTGS2 and Chac1 in EBV-infected GC cells. Western blot assays indicated that TFP suppressed the expression of NRF2, HO-1, GPX4 and xCT in EBV-infected GC cells. More importantly, overexpression of NRF2 could obviously rescue TFP-induced downregulation of GPX4 and xCT in EBV-infected GC cells. In summary, we showed novel data that TFP induced ferroptosis in EBV-infected GC cells by inhibiting NRF2/HO-1 signaling. The current findings may shed light on the potential clinical application of TFP in the treatment of EBVaGC.

Novel Insights on Ferroptosis Modulation as Potential Strategy for Cancer Treatment: When Nature Kills

Significance: The multifactorial nature of the mechanisms implicated in cancer development still represents a major issue for the success of established antitumor therapies. The discovery of ferroptosis, a novel form of programmed cell death distinct from apoptosis, along with the identification of the molecular pathways activated during its execution, has led to the uncovering of novel molecules characterized by ferroptosis-inducing properties. Recent advances: As of today, the ferroptosis-inducing properties of compounds derived from natural sources have been investigated and interesting findings have been reported both in vitro and in vivo. Critical Issues: Despite the efforts made so far, only a limited number of synthetic compounds have been identified as ferroptosis inducers, and their utilization is still limited to basic research. In this review, we analyzed the most important biochemical pathways involved in ferroptosis execution, with particular attention to the newest literature findings on canonical and non-canonical hallmarks, together with mechanisms of action of natural compounds identified as novel ferroptosis inducers. Compounds have been classified based on their chemical structure, and modulation of ferroptosis-related biochemical pathways has been reported. Future Directions: The outcomes herein collected represent a fascinating starting point from which to take hints for future drug discovery studies aimed at identifying ferroptosis-inducing natural compounds for anticancer therapies. Antioxid. Redox Signal. 40, 40-85.

Mitochondria-related signaling pathways involved in breast cancer regulate ferroptosis

Ferroptosis is a novel form of regulated cell death characterized by iron-dependent excessive lipid peroxidation. The core organelle involved in ferroptosis is mitochondria. Mitochondria undergoing ferroptosis are distinct from normal mitochondria in terms of morphology, biochemistry, gene expression, and energy metabolism. An increasing number of studies have shown that mitochondria and their associated metabolic pathways mediate ferroptosis in the development and progression of breast cancer. In this review, we discuss the relevant research about ferroptosis in breast cancer and provide a comprehensive summary of mitochondrial regulation in ferroptosis from the perspective of lipid metabolism, oxidative phosphorylation, ion metabolism, glycometabolism, and nucleotide metabolism. We also summarize the application of mitochondrial metabolism-related pathways as ferroptosis treatment targets. Here we provide new insights into the relationship between mitochondria, ferroptosis, and breast cancer treatment.

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.

Role of mitochondria in the regulation of ferroptosis and disease

Ferroptosis is a distinctive form of iron-dependent cell death characterized by significant ultrastructural changes in mitochondria. Given the crucial involvement of mitochondria in various cellular processes such as reactive oxygen species production, energy metabolism, redox status, and iron metabolism, mounting evidence suggests a vital role of mitochondria in the regulation and execution of ferroptosis. Furthermore, there exists a strong correlation between ferroptosis and various diseases. In this review, we aim to summarize the mechanisms underlying the induction and defense of ferroptosis, emphasizing the influence of mitochondria on this intricate process. Additionally, we provide an overview of the role of ferroptosis in disease, particularly cancer, and elucidate the mechanisms by which drugs targeting mitochondria impact ferroptosis. By presenting a theoretical foundation and reference point, this review aims to contribute to both basic cell biology research and the investigation of clinically relevant diseases.

Compensative Resistance to Erastin-Induced Ferroptosis in GPX4 Knock-Out Mutants in HCT116 Cell Lines

Ferroptosis results from the accumulation of oxidized and damaged lipids which then leads to programmed cell death. This programmed process is iron-dependent, and as a fundamental biological process, plays a crucial role in tissue homeostasis. The ferroptosis molecular pathway depends on self-regulatory genes: GPX4; TFRC; ACSL4; FSP1; SLC7A11, and PROM2. Some of them were considered here as ferro-sensitive or ferro-resistance markers. We examined the impact of GPX4 gene knock-out, using the CRISPR/Cas-9 technique, on ferroptosis induction in the HCT116 colorectal cancer cell line. The results confirmed that cells lacking the GPX4 gene (GPX4 KO) should be more susceptible to ferroptosis after erastin treatment. However, the decrease in cell viability was not as significant as we initially assumed. Based on the lipid peroxidation markers profile and RT-qPCR gene expression analysis, we revealed the activation of an alternative antioxidant system supporting GPX4 KO cells, mostly for cellular ferroptotic death avoidance. Increased expression of FSP1 and PRDX1 genes in knock-out mutants was associated with their function-recognized here as ferroptosis suppressors. For such reasons, studies on the role of GPX4 and other crucial genes from the ferroptotic pathway should be explored. Despite promising prospects, the utilization of ferroptosis mechanisms in cancer therapy remains at the stage of experimental and in vitro preclinical studies.

SOCS1 acts as a ferroptosis driver to inhibit the progression and chemotherapy resistance of triple-negative breast cancer

OBJECTIVES

Ferroptosis is involved in many types of cancers, including triple-negative breast cancer (TNBC). Suppressor of cytokine signaling 1 (SOCS1) has recently been implicated as a regulator of ferroptosis. We aim to explore whether targeting SOCS1 is a potential therapeutic strategy for TNBC therapy.

METHODS

Stable cell lines were constructed using lentivirus transfection. Cell viability was determined using CCK-8 and cell colony formation assays, respectively. Assays including lactate dehydrogenase release, lipid peroxidation and malondialdehyde assays were conducted to evaluate ferroptosis. Real-time quantitative polymerase chain reaction and western blotting were performed to evaluate mRNA and protein expression, respectively. A xenograft animal model was established by subcutaneous injection of cells into the flank.

RESULTS

Our results showed that SOCS1 overexpression inhibited cell proliferation and induced ferroptosis in TNBC cells, while SOCS1 knockdown promoted cell proliferation and reduced ferroptosis. We also found that SOCS1 regulated ferroptosis by modulating GPX4 expression. Furthermore, SOCS1 regulated cisplatin resistance in TNBC cells by promoting ferroptosis. Our in vivo data suggested that SOCS1 regulated tumor growth and cisplatin resistance in vivo.

CONCLUSIONS

SOCS1 inhibits the progression and chemotherapy resistance of TNBC by regulating GPX4 expression.

Urechistachykinin I induced ferroptosis by accumulating reactive oxygen species in Vibrio vulnificus

Antimicrobial peptides (AMPs), such as urechistachykinin I (LRQSQFVGSR-NH2), derived from urechis unicinctus, have demonstrated antimicrobial activities. It exhibits low cytotoxicity and selectivity between microbial and mammalian cells suggesting its potent antimicrobial ability. However, the underlying antimicrobial mechanisms remain unknown. Herein, we elucidated the antibacterial action against Vibrio vulnificus, focusing on the reactive oxygen species (ROS). ROS is crucial for antibiotic-mediated killing and oxidative stress. After treatment with urechistachykinin I, superoxide anions and hydroxyl radicals increase, and the overproduction of ROS leads to oxidative damage and destruction of the redox system. Oxidation of the defense system like glutathione or glutathione peroxidase 4 illustrates the dysfunction of cellular metabolism and induces lipid peroxidation attributed to depolarization and integrity brokerage. Cell death demonstrated these properties, and additional experiments, including iron accumulation, liperfluo, and DNA fragmentation, were promoted. The results demonstrated that urechistachykinin I-induced ferroptosis-like death in Vibrio vulnificus is dependent on ROS production. KEY POINTS: • Urechistachykinin I induce reactive oxygen species production • Urechistachykinin I cause oxidative damaged on the V. vulnificus • Urechistachykinin I ferroptosis-like death in V. vulnificus.

Tamoxifen induces ferroptosis in MCF-7 organoid

BACKGROUND

Breast cancer is the most common female malignant tumor type globally. The occurrence and development of breast cancer involve ferroptosis, which is closely related to its treatment. The development of breast cancer organoids facilitates the analysis of breast cancer molecular background and tumor biological behavior, including clinical pathological characteristics, drug response, or drug resistance relationship, and promotes the advancement of precision treatment for breast cancer. The three-dimensional (3D) cell culture of breast cancer MCF-7 organoid is more similar to the in vivo environment and thus obtains more realistic results than 2D cell culture. Our study examined the new mechanism of tamoxifen in treating breast cancer through breast cancer MCF-7 organoids.

METHODS

We used 3D cells to culture breast cancer MCF-7 organoid, as well as tamoxifen-treated MCF-7 and tamoxifen-resistant MCF-7 (MCF-7 TAMR) cells. We used transcriptome sequencing. We detected GPX4 and SLC7A11 protein levels using Western blotting and the content of ATP, glutathione, and ferrous ions using the Cell Counting Lite 3D Kit. We assessed cell viability using the Cell Counting Kit-8 (CCK-8) assay.

RESULTS

Tamoxifen significantly inhibited the growth of MCF-7 organoids and significantly induced ferroptosis in MCF-7 organoids. The ferroptosis inhibitor reversed the significant tamoxifen-induced MCF-7 organoid inhibition activity. Moreover, the ferroptosis activator enhanced the tamoxifen-induced MCF-7 TAMR cell activity inhibition.

CONCLUSION

Our study revealed that ferroptosis plays an important role in tamoxifen-induced MCF-7 organoid cell death and provides a new research idea for precise treatment of breast cancer through an organoid model.

Role of GPX4 inhibition-mediated ferroptosis in the chemoresistance of ovarian cancer to Taxol in vitro

BACKGROUND

Ovarian cancer remains a common gynecological tumor and the fifth leading cause of death worldwide. Taxol-based chemotherapy is a standard approach to the treatment of ovarian cancer. Glutathione peroxidase 4 (GPX4) is the key regulator of ferroptosis, which is an important form of cell death. Here, we investigate the effect of GPX4 inhibition-mediated ferroptosis on the sensitivity of ovarian cancer cells to Taxol.

METHODS AND RESULTS

A2780/PTX and OVCAR-3/PTX Taxol-resistant ovarian cancer cells were established, and stable GPX4 knockout cell lines were generated via lentivirus GPX4-sgRNA. The GPX4 expression level, the apoptosis rate and cell viability were analyzed. The levels of ferroptosis-related factor indicators such as malondialdehyde (MDA) and reactive oxygen species (ROS) were measured. The results showed that the GPX4 protein and mRNA levels were increased in the Taxol-resistant cells. Moreover, GPX4 knockout reduced cell viability and inhibited the colony formation rate. In addition, we found that GPX4 inhibition increased Taxol sensitivity by inducing ferroptosis.

CONCLUSIONS

In summary, our studies reveal that GPX4 inhibition promotes ferroptosis and increases the sensitivity of ovarian cancer cells to Taxol in vitro.

Harnessing Ferroptosis to Overcome Drug Resistance in Colorectal Cancer: Promising Therapeutic Approaches

Drug resistance remains a significant challenge in the treatment of colorectal cancer (CRC). In recent years, the emerging field of ferroptosis, a unique form of regulated cell death characterized by iron-dependent lipid peroxidation, has offered new insights and potential therapeutic strategies for overcoming drug resistance in CRC. This review examines the role of ferroptosis in CRC and its impact on drug resistance. It highlights the distinctive features and advantages of ferroptosis compared to other cell death pathways, such as apoptosis and necrosis. Furthermore, the review discusses current research advances in the field, including novel treatment approaches that target ferroptosis. These approaches involve the use of ferroptosis inducers, interventions in iron metabolism and lipid peroxidation, and combination therapies to enhance the efficacy of ferroptosis. The review also explores the potential of immunotherapy in modulating ferroptosis as a therapeutic strategy. Additionally, it evaluates the strengths and limitations of targeting ferroptosis, such as its selectivity, low side effects, and potential to overcome resistance, as well as challenges related to treatment specificity and drug development. Looking to the future, this review discusses the prospects of ferroptosis-based therapies in CRC, emphasizing the importance of further research to elucidate the interaction between ferroptosis and drug resistance. It proposes future directions for more effective treatment strategies, including the development of new therapeutic approaches, combination therapies, and integration with emerging fields such as precision medicine. In conclusion, harnessing ferroptosis represents a promising avenue for overcoming drug resistance in CRC. Continued research efforts in this field are crucial for optimizing therapeutic outcomes and providing hope for CRC patients.

Ferroptosis: the emerging player in remodeling triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a highly heterogeneous breast tumor type that is highly malignant, invasive, and highly recurrent. Ferroptosis is a unique mode of programmed cell death (PCD) at the morphological, physiological, and molecular levels, mainly characterized by cell death induced by iron-dependent accumulation of lipid peroxides, which plays a substantial role in a variety of diseases, including tumors and inflammatory diseases. TNBC cells have been reported to display a peculiar equilibrium metabolic profile of iron and glutathione, which may increase the sensitivity of TNBC to ferroptosis. TNBC possesses a higher sensitivity to ferroptosis than other breast cancer types. Ferroptosis also occurred between immune cells and tumor cells, suggesting that regulating ferroptosis may remodel TNBC by modulating the immune response. Many ferroptosis-related genes or molecules have characteristic expression patterns and are expected to be diagnostic targets for TNBC. Besides, therapeutic strategies based on ferroptosis, including the isolation and extraction of natural drugs and the use of ferroptosis inducers, are urgent for TNBC personalized treatment. Thus, this review will explore the contribution of ferroptosis in TNBC progression, diagnosis, and treatment, to provide novel perspectives and therapeutic strategies for TNBC management.

Iron, Ferroptosis, and Head and Neck Cancer

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

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.

Neutrophil extracellular traps mediate TLR9/Merlin axis to resist ferroptosis and promote triple negative breast cancer progression

Neutrophil and neutrophil extracellular traps (NETs) were reported to be associated with tumor development, but the exact role and concrete mechanisms are still poorly understood, especially in triple negative breast cancer (TNBC). In this study, our results exhibited that NETs formation in TNBC tissues was higher than that in non-TNBC tissues, and NETs formation was distinctly correlated with tumor size, ki67 level and lymph node metastasis in TNBC patients. Subsequent in vivo experiments demonstrated that NETs inhibition could suppress TNBC tumor growth and lung metastasis. Further in vitro experiments uncovered that oncogenic function of NETs on TNBC cells were possibly dependent on TLR9 expression. We also found that neutrophils from peripheral blood of TNBC patients with postoperative fever were prone to form NETs and could enhance the proliferation and invasion of TNBC cells. Mechanistically, we revealed that NETs could interact with TLR9 to decrease Merlin phosphorylation which contributed to TNBC cell ferroptosis resistance. Our work provides a novel insight into the mechanism of NETs promoting TNBC progression and blocking the key modulator of NETs might be a promising therapeutic strategy in TNBC.

Rewiring of mitochondrial metabolism in therapy-resistant cancers: permanent and plastic adaptations

Deregulation of tumor cell metabolism is widely recognized as a "hallmark of cancer." Many of the selective pressures encountered by tumor cells, such as exposure to anticancer therapies, navigation of the metastatic cascade, and communication with the tumor microenvironment, can elicit further rewiring of tumor cell metabolism. Furthermore, phenotypic plasticity has been recently appreciated as an emerging "hallmark of cancer." Mitochondria are dynamic organelles and central hubs of metabolism whose roles in cancers have been a major focus of numerous studies. Importantly, therapeutic approaches targeting mitochondria are being developed. Interestingly, both plastic (i.e., reversible) and permanent (i.e., stable) metabolic adaptations have been observed following exposure to anticancer therapeutics. Understanding the plastic or permanent nature of these mechanisms is of crucial importance for devising the initiation, duration, and sequential nature of metabolism-targeting therapies. In this review, we compare permanent and plastic mitochondrial mechanisms driving therapy resistance. We also discuss experimental models of therapy-induced metabolic adaptation, therapeutic implications for targeting permanent and plastic metabolic states, and clinical implications of metabolic adaptations. While the plasticity of metabolic adaptations can make effective therapeutic treatment challenging, understanding the mechanisms behind these plastic phenotypes may lead to promising clinical interventions that will ultimately lead to better overall care for cancer patients.

Recent advances in targeted strategies for triple-negative breast cancer

Triple-negative breast cancer (TNBC), a highly aggressive subtype of breast cancer, negatively expresses estrogen receptor, progesterone receptor, and the human epidermal growth factor receptor 2 (HER2). Although chemotherapy is the main form of treatment for patients with TNBC, the effectiveness of chemotherapy for TNBC is still limited. The search for more effective therapies is urgent. Multiple targeted therapeutic strategies have emerged according to the specific molecules and signaling pathways expressed in TNBC. These include PI3K/AKT/mTOR inhibitors, epidermal growth factor receptor inhibitors, Notch inhibitors, poly ADP-ribose polymerase inhibitors, and antibody-drug conjugates. Moreover, immune checkpoint inhibitors, for example, pembrolizumab, atezolizumab, and durvalumab, are widely explored in the clinic. We summarize recent advances in targeted therapy and immunotherapy in TNBC, with the aim of serving as a reference for the development of individualized treatment of patients with TNBC in the future.

Irreversible HER2 inhibitors overcome resistance to the RSL3 ferroptosis inducer in non-HER2 amplified luminal breast cancer

Ferroptosis, a form of programed cell death, can be promoted by inhibitors of the xCT transporter (erastin) or GPX4 (RSL3). We found that GPX4, but not the xCT transporter, is selectively elevated in luminal breast cancer. Consistent with this observation, the majority of luminal breast cancer cell lines are exquisitely sensitive to RSL3 with limited sensitivity to erastin. In RSL3-resistant, but not sensitive, luminal breast cancer cell lines, RSL3 induces HER2 pathway activation. Irreversible HER2 inhibitors including neratinib reversed RSL3 resistance in constitutively RSL3-resistant cell lines. Combination treatment with RSL3 and neratinib increases ferroptosis through mitochondrial iron-dependent reactive oxygen species production and lipid peroxidation. RSL3 also activated replication stress and concomitant S phase and G2/M blockade leading to sensitivity to targeting the DNA damage checkpoint. Together, our data support the exploration of RSL3 combined with irreversible HER2 inhibitors in clinical trials.

Effect of tumor-associated macrophages on the pyroptosis of breast cancer tumor cells

Macrophages are immune cells with high plasticity that are widely distributed in all tissues and organs of the body. Under the influence of the immune microenvironment of breast tumors, macrophages differentiate into various germline lineages. They exert pro-tumor or tumor-suppressive effects by secreting various cytokines. Pyroptosis is mediated by Gasdermin family proteins, which form holes in cell membranes and cause a violent inflammatory response and cell death. This is an important way for the body to fight off infections. Tumor cell pyroptosis can activate anti-tumor immunity and inhibit tumor growth. At the same time, it releases inflammatory mediators and recruits tumor-associated macrophages (TAMs) for accumulation. Macrophages act as "mediators" of cytokine interactions and indirectly influence the pyroptosis pathway. This paper describes the mechanism of action on the part of TAM in affecting the pyroptosis process of breast tumor cells, as well as its key role in the tumor microenvironment. Additionally, it provides the basis for in-depth research on how to use immune cells to affect breast tumors and guide anti-tumor trends, with important implications for the prevention and treatment of breast tumors. Video Abstract.

Copper homeostasis-associated gene PRNP regulates ferroptosis and immune infiltration in breast cancer

Breast cancer (BRCA) is one of the most common cancers in women. Copper (Cu) is an essential trace element implicated in many physiological processes and human diseases, including BRCA. In this study, we performed bioinformatics analysis and experiments to determine differentially expressed copper homeostasis-associated genes in BRCA. Based on two Gene Expression Omnibus (GEO) datasets, the copper homeostasis-associated gene, prion protein (PRNP), a highly conserved ubiquitous glycoprotein, was significantly down-regulated in BRCA compared to normal tissues. Moreover, PRNP expression predicted a better prognosis in BRCA patients. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that PRNP was potentially linked with several cancer-associated signaling pathways, including regulation of inflammatory response and oxidative phosphorylation. To validate the biological functions of PRNP, we overexpressed PRNP in BRCA cell lines, MDA-MB-231 and BT-549. CCK8 assay showed that PRNP overexpression significantly increased the sensitivity of gefitinib in BRCA cells. Overexpression of PRNP resulted in increased reactive oxygen species (ROS) production upon gefitinib treatment and ferroptosis selective inhibitor, ferrostatin-1 attenuated the enhanced ROS production effect of PRNP in BRCA cells. PRNP expression was positively correlated with macrophages, Th1 cells, neutrophils, and B cells, while negatively correlated with NK CD56 bright cells and Th17 cells in BRCA. Single-cell analysis showed that PRNP was highly expressed in M1 phenotype macrophages, essential tumor-suppressing cells in the tumor stroma. Therefore, our findings suggest that PRNP may participate in ROS-mediated ferroptosis and is a potential novel therapeutic target of chemotherapy and immunotherapy in BRCA.

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.

Ferroptosis, a new form of cell death: mechanisms, biology and role in gynecological malignant tumor

Ferroptosis, a term coined by Dixon et al. in 2012, refers to an iron-dependent form of regulated cell death driven by an overload of lipid peroxides on cellular membranes. It is morphologically and mechanistically distinct from apoptosis and other types of regulated cell death. Many studies have confirmed that ferroptosis is involved in the occurrence and development of many diseases, such as neurodegenerative diseases, chronic cardiovascular diseases, respiratory diseases and even tumors. While in the systemic diseases of obstetrics and gynecology, the related researches are still limited. In this article, we retrieved PubMed and WEB OF SCI databases for articles and reviews published before May 6, 2022, using "ferroptosis, ferroptosis regulator, gynecological tumors" as keywords, and comprehensively reviewed on their basis. Here, we systematically summarize the studies on the mechanism and characteristics of ferroptosis, investigate the role of ferroptosis in clinical systemic diseases of obstetrics and gynecology, evaluate the research status, unsolved problems and further research directions of ferroptosis, so as to let people learn more about ferroptosis and establish a research foundation for the exploration of the treatment strategies for ferroptosis-mediated diseases.

Nanoparticle-mediated synergistic anticancer effect of ferroptosis and photodynamic therapy: Novel insights and perspectives

Current antitumor monotherapy has many limitations, highlighting the need for novel synergistic anticancer strategies. Ferroptosis is an iron-dependent form of nonapoptotic cell death that plays a pivotal regulatory role in tumorigenesis and treatment. Photodynamic therapy (PDT) causes irreversible chemical damage to target lesions and is widely used in antitumor therapy. However, PDT's effectiveness is usually hindered by several obstacles, such as hypoxia, excess glutathione (GSH), and tumor resistance. Ferroptosis improves the anticancer efficacy of PDT by increasing oxygen and reactive oxygen species (ROS) or reducing GSH levels, and PDT also enhances ferroptosis induction due to the ROS effect in the tumor microenvironment (TME). Strategies based on nanoparticles (NPs) can subtly exploit the potential synergy of ferroptosis and PDT. This review explores recent advances and current challenges in the landscape of the underlying mechanisms regulating ferroptosis and PDT, as well as nano delivery system-mediated synergistic anticancer activity. These include polymers, biomimetic materials, metal organic frameworks (MOFs), inorganics, and carrier-free NPs. Finally, we highlight future perspectives of this novel emerging paradigm in targeted cancer therapies.

An integrative review of nonobvious puzzles of cellular and molecular cardiooncology

Oncologic patients are subjected to four major treatment types: surgery, radiotherapy, chemotherapy, and immunotherapy. All nonsurgical forms of cancer management are known to potentially violate the structural and functional integrity of the cardiovascular system. The prevalence and severity of cardiotoxicity and vascular abnormalities led to the emergence of a clinical subdiscipline, called cardiooncology. This relatively new, but rapidly expanding area of knowledge, primarily focuses on clinical observations linking the adverse effects of cancer therapy with deteriorated quality of life of cancer survivors and their increased morbidity and mortality. Cellular and molecular determinants of these relations are far less understood, mainly because of several unsolved paths and contradicting findings in the literature. In this article, we provide a comprehensive view of the cellular and molecular etiology of cardiooncology. We pay particular attention to various intracellular processes that arise in cardiomyocytes, vascular endothelial cells, and smooth muscle cells treated in experimentally-controlled conditions in vitro and in vivo with ionizing radiation and drugs representing diverse modes of anti-cancer activity.

Targeting GPX4 in human cancer: Implications of ferroptosis induction for tackling cancer resilience

Cancer metabolic alterations have been emphasized to protect cancer cells from cell death. The metabolic reprogramming toward a mesenchymal state makes cancer cells resistant to therapy but vulnerable to ferroptosis induction. Ferroptosis is a new form of regulated cell death based on the iron-dependent accumulation of excessive lipid peroxidation. Glutathione peroxidase 4 (GPX4) is the core regulator of ferroptosis by detoxifying cellular lipid peroxidation using glutathione as a cofactor. GPX4 synthesis requires selenium incorporation into the selenoprotein through isopentenylation and selenocysteine tRNA maturation. GPX4 synthesis and expression can be regulated by multiple levels of its transcription, translation, posttranslational modifications, and epigenetic modifications. Targeting GPX4 in cancer may be a promising strategy for effectively inducing ferroptosis and killing therapy-resistant cancer. Several pharmacological therapeutics targeting GPX4 have been developed constantly to activate ferroptosis induction in cancer. The potential therapeutic index of GPX4 inhibitors remains to be tested with thorough examinations of their safety and adverse effects in vivo and clinical trials. Many papers have been published continuously in recent years, requiring state-of-the-art updates in targeting GPX4 in cancer. Herein, we summarize targeting the GPX4 pathway in human cancer, which leads to implications of ferroptosis induction for tackling cancer resilience.

PGRMC1 promotes triple-negative breast cancer cell growth via suppressing ferroptosis

OBJECTIVE

Triple-negative breast cancer (TNBC) is the most malignant form of breast cancer with increasing incidence and mortality worldwide. The progesterone receptor membrane component-1 (PGRMC1) is a well-identified hormone receptor with unknown functions in TNBC. The current study aims to explore the involvement of PGRMC1 in regulation of glutathione metabolism and ferroptosis during development of TNBC, providing new therapy options for TNBC patients.

METHODS

Bioinformatic analysis, cell proliferation assay, western blot assay and other biochemistry methods were performed in TNBC cells.

RESULTS

Our results revealed that the expression of PGRMC1 is higher in TNBC than the other subtypes of breast cancer. Interestingly, as an iron binding protein, increased PGRMC1 expression in TNBC cells leads to resistance to ferroptosis inducer. On the contrary, silenced PGRMC1 expression enhanced sensitivity of MDA-MB231 cells to Erastin. Mechanistically, overexpression of PGRMC1 decreased the intracellular free iron concentration, which was reduced by AG205 treatment.

CONCLUSIONS

PGRMC1 increases the possibility of TNBC development through binding to intracellular iron and suppressing ferroptosis, providing the molecular basis of combined treatment for TNBC.

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.

Potent nanoreactor-mediated ferroptosis-based strategy for the reversal of cancer chemoresistance to Sorafenib

The drug resistance of cancer cells is related to a variety of mechanisms, among which the destruction of redox homeostasis is one of the key factors. Ferroptosis, an intracellular iron-dependent form of cell death, is related to the production of oxidative stress. The accumulation of lipid peroxidation (LPO) during ferroptosis disrupts intracellular redox homeostasis, thereby affecting the sensitivity of tumor cells to drugs. In this work, we proposed a ferroptosis strategy based on LPO accumulation, reduced glutathione generation via inhibition of SLC3A2 protein and inactivated glutathione peroxidase 4 (GPX4) to reverse the chemoresistance of cancer cells. The Fenton reaction based on the ferroptosis-inducing nanoreactors (Au/Fe-GA/Sorafenib@PEG) not only generated hydroxyl radicals (·OH) under laser irradiation to realize the accumulation of LPO, but also depleted GSH to increase the accumulation of LPO. Meanwhile, the cystine uptake of cells was inhibited by Sorafenib, resulting in reduced GSH synthesis and inactivated GPX4. In vitro and in vivo experiments demonstrated AFG/SFB@PEG + Laser group could inactivate GPX4 and the enhanced ferroptosis can reverse chemo-resistance caused by continuous upregulation of GPX4 levels in cells through 'self-rescue'. The study proposed the mechanism and feasibility of ferroptosis to reverse drug resistance, providing a promising strategy for chemo-resistant cancer treatment. STATEMENT OF SIGNIFICANCE: Herein, we proposed a ferroptosis strategy based on LPO accumulation, reduced glutathione generation via inhibition of SLC3A2 protein, and inactivated glutathione peroxidase 4 (GPX4) to reverse chemoresistance of cancer cells. The Fenton reaction based on the ferroptosis-inducing nanoreactors (Au/Fe-GA/Sorafenib@PEG) not only generated hydroxyl radicals (·OH) under laser irradiation to realize the accumulation of LPO but also depleted GSH to increase the accumulation of LPO. Meanwhile, the cystine uptake of cells was inhibited by Sorafenib, resulting in reduced GSH synthesis and inactivated GPX4. In vitro and in vivo experiments demonstrated AFG/SFB@PEG + Laser group could inactivate GPX4 and the enhanced ferroptosis can reverse chemo-resistance caused by continuous upregulation of GPX4 levels in cells through 'self-rescue'.

Development and validation of a combined hypoxia and ferroptosis prognostic signature for breast cancer

Background

Hypoxia is involved in tumor biological processes and disease progression. Ferroptosis, as a newly discovered programmed cell death process, is closely related to breast cancer (BC) occurrence and development. However, reliable prognostic signatures based on a combination of hypoxia and ferroptosis in BC have not been developed.

Method

We set The Cancer Genome Atlas (TCGA) breast cancer cohort as training set and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) BC cohort as the validation set. Least Absolute Shrinkage and Selection Operator (LASSO) and COX regression approaches were used to construct ferroptosis-related genes (FRGs) and hypoxia-related genes (HRGs) prognostic signature (HFRS). The CIBERSORT algorithm and ESTIMATE score were used to explore the relationship between HFRS and tumor immune microenvironment. Immunohistochemical staining was used to detect protein expression in tissue samples. A nomogram was developed to advance the clinical application of HFRS signature.

Results

Ten ferroptosis-related genes and hypoxia-related genes were screened to construct the HFRS prognostic signature in TCGA BC cohort, and the predictive capacity was verified in METABRIC BC cohort. BC patients with high-HFRS had shorter survival time, higher tumor stage, and a higher rate of positive lymph node. Moreover, high HFRS was associated with high hypoxia, ferroptosis, and immunosuppression status. A nomogram that was constructed with age, stage, and HFRS signature showed a strong prognostic capability to predict overall survival (OS) for BC patients.

Conclusion

We developed a novel prognostic model with hypoxia and ferroptosis-related genes to predict OS, and characterize the immune microenvironment of BC patients, which might provide new cures for clinical decision-making and individual treatment of BC patients.

Iron nitroprusside as a chemodynamic agent and inducer of ferroptosis for ovarian cancer therapy

ChemoDynamic Therapy (CDT) is a powerful therapeutic modality using Fenton/Fenton-like reactions to produce oxidative stress for cancer treatment. However, the insufficient amount of catalyst ions and ROS scavenging activity of glutathione peroxidase (GPX4) limit the application of this approach. Therefore, a tailored strategy to regulate the Fenton reaction more efficiently (utilizing dual metal cations) and inhibit the GPX4 activity, is in great demand. Herein, a CDT system is based on dual (Fe²⁺ metals) iron pentacyanonitrosylferrate or iron nitroprusside (FeNP) having efficient ability to catalyze the reaction of endogenous H₂O₂ to form highly toxic ˙OH species in cells. Additionally, FeNP is involved in ferroptosis via GPX4 inhibition. In particular, FeNP was structurally characterized, and it is noted that a minimum dose of FeNP is required to kill cancer cells while a comparable dose shows negligible toxicity on normal cells. Detailed in vitro studies confirmed that FeNP participates in sustaining apoptosis, as determined using the annexin V marker. Cellular uptake results showed that in a short time period, FeNP enters lysosomes and, due to the acidic lysosomal pH, releases Fe²⁺ ions, which are involved in ROS generation (˙OH species). Western blot analyses confirmed the suppression of GPX4 activity over time. Importantly, FeNP has a therapeutic effect on ovarian cancer organoids derived from High-Grade Serous Ovarian Cancer (HGSOC). Furthermore, FeNP showed biocompatible nature towards normal mouse liver organoids and in vivo. This work presents the effective therapeutic application of FeNP as an efficient Fenton agent along with ferroptosis inducer activity to improve CDT, through disturbing redox homeostasis.

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

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

Studying ferroptosis and iron metabolism pre- and post-radiotherapy treatment in breast cancer patients

BACKGROUND

Radiotherapy (RT) is an important part of the treatment of many tumors. Radiotherapy causes oxidative damage in all cellular compartments, including lipid membrane, on a random basis. Toxic lipid peroxidation accumulation has only lately been linked to a regulated type of cell death known as ferroptosis. Iron is required for ferroptosis sensitization in cells.

AIM OF THE WORK

This work aimed to study ferroptosis and iron metabolism before and after RT in BC patients.

SUBJECTS AND METHODS

Eighty participants were included divided into two main groups: group I: 40 BC patients treated with RT. Group II: 40 healthy volunteers' age and sex matched as control group. Venous blood samples were collected from BC patients (prior to and after RT) and healthy controls. Glutathione (GSH), malondialdehyde (MDA), serum iron levels and % of transferrin saturation were measured by colorimetric technique. Ferritin, ferroportin, and prostaglandin-endoperoxide synthase 2 (PTGS2) levels were assessed by ELISA.

RESULTS

Serum ferroportin, reduced glutathione, and ferritin showed significant decrease after radiotherapy in comparison to before radiotherapy. However, there was significant increase in serum PTGS2, MDA, % of transferrin saturation and iron levels after radiotherapy in comparison to before radiotherapy.

CONCLUSION

Radiotherapy induced ferroptosis in breast cancer patients as a new cell death mechanism and PTGS2 is a biomarker of ferroptosis. Iron modulation is a useful approach for the treatment of BC especially if combined with targeted therapy and immune-based therapy. Further studies are warranted to be translated into clinical compounds.