Combined treatment with cotylenin A and phenethyl isothiocyanate induces strong antitumor activity mainly through the induction of ferroptotic cell death in human pancreatic cancer cells

Mechanoredox-Enabled Isothiocyanation of Primary Amines Using Piezoelectric Material as the Redox Catalyst

A novel mechanoredox-enabled synthesis of aromatic and aliphatic isothiocyanates from primary amines and carbon disulfide under ball milling conditions using a piezoelectric material (BaTiO3) as the redox catalyst has been developed. This method displays several features, such as short reaction time, operational simplicity, room temperature and air conditions, minimal solvent, broad substrate scope, and recyclable cheap catalyst. Preliminary mechanistic studies revealed that highly polarized piezoelectric material acted as a single-electron transfer (SET) oxidation reagent for the key desulfurization process.

Exogenous dihomo-γ-linolenic acid triggers ferroptosis via ACSL4-mediated lipid metabolic reprogramming in acute myeloid leukemia cells

Ferroptosis is a novel type of programmed cell death caused by excessive iron-dependent lipid peroxidation. According to various studies, there may be a link between ferroptosis and lipid metabolism. However, few studies have been reported on the lipid metabolism of ferroptosis in acute myeloid leukemia (AML). Here, we analyzed the relationship between lipid metabolism and ferroptosis in AML cells to explore new clinical treatment strategies. This study found that 12 fatty acids were significantly changed in acute myeloid leukemia cell ferroptosis, including dihomo-γ-linolenic acid (DGLA), arachidonic acid (AA), docosahexaenoic acid (DHA), etc. Exogenous DGLA substantially increases the sensitivity to ferroptosis and induces ferroptosis alone in AML cells. In addition, acyl-CoA synthetase long-chain family member 4 (ACSL4) knockout significantly inhibited DGLA-induced AML cells ferroptosis, and ACSL4 regulates DGLA-associated lipid synthesis to affect the sensitivity of AML cells to ferroptosis. Collectively, our studies indicate that a DGLA-enriched diet significantly restricted the growth of leukemia cells as well as induced ferroptosis in vivo.

Investigating the interaction between calcium signaling and ferroptosis for novel cancer treatment

BACKGROUND

Drug resistance in cancer is steadily rising, making the development of new therapeutic targets increasingly critical for improving treatment outcomes.

PURPOSE

The mutual regulation of ions is essential for cell growth. Based on this concept, ion interference strategies offer a highly effective approach for cancer treatment. Calcium ions (Ca2+), as major second messengers, are closely associated with ion exchange and homeostasis. Disruptions in this balance can lead to cell death. However, while iron ions are also crucial, the connection between Ca2+and iron-induced cell death (ferroptosis) has not been well established. Therefore, this study suggests that Ca2+ may play a role in the induction of ferroptosis, presenting a novel and efficient target for cancer therapy.

STUDY DESIGN

PubMed, Google Scholar, and Web of Science databases were systematically searched for articles published in the past 15 years on the mechanisms of calcium ion-induced ferroptosis in cancer and related drugs.

RESULTS

The analysis highlights how Ca2+regulate ferroptosis. The mechanisms by which Ca2+influence ferroptosis are summarized based on existing literature, and relevant drugs that act on Ca2+/ferroptosis axis are outlined.

CONCLUSION

Ca2+ regulate ferroptosis primarily through the modulation of reactive oxygen species (ROS) and glutathione (GSH) levels, a mechanism that applies to a wide range of cancer cells as well as paracancerous and normal cells in cancer treatment. Furthermore, plant-derived active compounds exhibit potent anticancer properties and often act on the Ca2+/ferroptosis axis. These natural compounds could play a significant role in the development of new cancer treatment strategies.

The Role of Iron in Atherosclerosis and its Association with Related Diseases

PURPOSE OF REVIEW

This review aims to elucidate the multifaceted role of iron in the pathogenesis of atherosclerosis. The primary objective is to summarize recent advances in understanding how iron contributes to atherosclerosis through various cellular mechanisms. Additionally, the review explores the therapeutic implications of targeting iron metabolism in the prevention and treatment of cardiovascular diseases.

RECENT FINDINGS

A growing body of literature suggests that excess iron accelerates the progression of atherosclerosis, with the deleterious form of iron, non-transferrin-bound iron (NTBI), particularly exacerbating this process. Furthermore, iron overload has been demonstrated to play a pivotal role in endothelial cells, vascular smooth muscle cells, and macrophages, contributing to plaque instability and disease progression by promoting lipid peroxidation, oxidative stress, inflammatory responses, and ferroptosis. Iron plays a complex role in atherosclerosis, influencing multiple cellular processes and promoting disease progression. By promoting oxidative stress, inflammation, and ferroptosis, iron exacerbates endothelial dysfunction, smooth muscle cell calcification, and the formation of macrophage-derived foam cells. Targeted therapies focusing on iron metabolism have proven effective in treating atherosclerosis and other cardiovascular diseases.

Natural products targeting ferroptosis pathways in cancer therapy (Review)

Ferroptosis inducers (FIN) have a key role in cancer therapy and provide novel and innovative treatment strategies. Although many researchers have performed FIN screening of synthetic compounds, studies on the identification of FIN from natural products are limited, particularly in the field of drug development and combination therapy. In this review, this gap was addressed by comprehensively summarizing recent studies on ferroptosis. The causes of ferroptosis were categorized into driving and defensive factors, elucidating key pathways and targets. Next, through summarizing research on natural products that induce ferroptosis, the study elaborated in detail on the natural products that have FIN functions. Their discovery and development were also described and insight for clinical drug development was provided. In addition, the mechanisms of action were analyzed and potential combination therapies, resistance reversal and structural enhancements were presented. By highlighting the potential of natural products in inducing ferroptosis for cancer treatment, this review may serve as a reference for utilizing these compounds against cancer. It not only showed the significance of natural products but may also promote further investigation into their therapeutic effects, thus encouraging research in this field.

Recent advancements in nanomaterial-mediated ferroptosis-induced cancer therapy: Importance of molecular dynamics and novel strategies

Ferroptosis is a novel type of controlled cell death resulting from an imbalance between oxidative harm and protective mechanisms, demonstrating significant potential in combating cancer. It differs from other forms of cell death, such as apoptosis and necrosis. Molecular therapeutics have hard time playing the long-acting role of ferroptosis induction due to their limited water solubility, low cell targeting capacity, and quick metabolism in vivo. To this end, small molecule inducers based on biological factors have long been used as strategy to induce cell death. Research into ferroptosis and advancements in nanotechnology have led to the discovery that nanomaterials are superior to biological medications in triggering ferroptosis. Nanomaterials derived from iron can enhance ferroptosis induction by directly releasing large quantities of iron and increasing cell ROS levels. Moreover, utilizing nanomaterials to promote programmed cell death minimizes the probability of unfavorable effects induced by mutations in cancer-associated genes such as RAS and TP53. Taken together, this review summarizes the molecular mechanisms involved in ferroptosis along with the classification of ferroptosis induction. It also emphasized the importance of cell organelles in the control of ferroptosis in cancer therapy. The nanomaterials that trigger ferroptosis are categorized and explained. Iron-based and noniron-based nanomaterials with their characterization at the molecular and cellular levels have been explored, which will be useful for inducing ferroptosis that leads to reduced tumor growth. Within this framework, we offer a synopsis, which traverses the well-established mechanism of ferroptosis and offers practical suggestions for the design and therapeutic use of nanomaterials.

Understanding the Novel Approach of Nanoferroptosis for Cancer Therapy

As a new form of regulated cell death, ferroptosis has unraveled the unsolicited theory of intrinsic apoptosis resistance by cancer cells. The molecular mechanism of ferroptosis depends on the induction of oxidative stress through excessive reactive oxygen species accumulation and glutathione depletion to damage the structural integrity of cells. Due to their high loading and structural tunability, nanocarriers can escort the delivery of ferro-therapeutics to the desired site through enhanced permeation or retention effect or by active targeting. This review shed light on the necessity of iron in cancer cell growth and the fascinating features of ferroptosis in regulating the cell cycle and metastasis. Additionally, we discussed the effect of ferroptosis-mediated therapy using nanoplatforms and their chemical basis in overcoming the barriers to cancer therapy.

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.

Emerging trends of phytochemicals as ferroptosis modulators in cancer therapy

Ferroptosis, a novel form of regulated cell death characterized by dependence on iron and lipid peroxidation, has been implicated in a wide range of clinical conditions including neurological diseases, cardiovascular disorders, acute kidney failure, and various types of cancer. Therefore, it is critical to suppress cancer progression and proliferation. Ferroptosis can be triggered in cancer cells and some normal cells by synthetic substances, such as erastin, Ras-selective lethal small molecule-3, or clinical pharmaceuticals. Natural bioactive compounds are traditional drug discovery tools, and some have been therapeutically used as dietary additives or pharmaceutical agents against various malignancies. The fact that natural products have multiple targets and minimal side effects has led to notable advances in anticancer research. Research has indicated that ferroptosis can also be induced by natural compounds during cancer treatment. In this review, we focused on the most recent developments in emerging molecular processes and the significance of ferroptosis in cancer. To provide new perspectives on the future development of ferroptosis-related anticancer medications, we also provide a summary of the implications of natural phytochemicals in triggering ferroptosis through ROS production and ferritinophagy induction in a variety of malignancies.

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: Emerging Role in Diseases and Potential Implication of Bioactive Compounds

Ferroptosis is a form of cell death that is distinguished from other types of death for its peculiar characteristics of death regulated by iron accumulation, increase in ROS, and lipid peroxidation. In the past few years, experimental evidence has correlated ferroptosis with various pathological processes including neurodegenerative and cardiovascular diseases. Ferroptosis also is involved in several types of cancer because it has been shown to induce tumor cell death. In particular, the pharmacological induction of ferroptosis, contributing to the inhibition of the proliferative process, provides new ideas for the pharmacological treatment of cancer. Emerging evidence suggests that certain mechanisms including the Xc- system, GPx4, and iron chelators play a key role in the regulation of ferroptosis and can be used to block the progression of many diseases. This review summarizes current knowledge on the mechanism of ferroptosis and the latest advances in its multiple regulatory pathways, underlining ferroptosis' involvement in the diseases. Finally, we focused on several types of ferroptosis inducers and inhibitors, evaluating their impact on the cell death principal targets to provide new perspectives in the treatment of the diseases and a potential pharmacological development of new clinical therapies.

Iron-Dependent Cell Death: A New Treatment Approach against Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a devastating tumor type where a very high proportion of people diagnosed end up dying from cancer. Surgical resection is an option for only about 20% of patients, where the 5-year survival increase ranges from 10 to 25%. In addition to surgical resection, there are adjuvant chemotherapy schemes, such as FOLFIRINOX (a mix of Irinotecan, oxaliplatin, 5-Fluorouraci and leucovorin) or gemcitabine-based treatment. These last two drugs have been compared in the NAPOLI-3 clinical trial, and the NALIRIFOX arm was found to have a higher overall survival (OS) (11.1 months vs. 9.2 months). Despite these exciting improvements, PDAC still has no effective treatment. An interesting approach would be to drive ferroptosis in PDAC cells. A non-apoptotic reactive oxygen species (ROS)-dependent cell death, ferroptosis was first described by Dixon et al. in 2012. ROS are constantly produced in the tumor cell due to high cell metabolism, which is even higher when exposed to chemotherapy. Tumor cells have detoxifying mechanisms, such as Mn-SOD or the GSH-GPX system. However, when a threshold of ROS is exceeded in the tumor cell, the cell's antioxidant systems are overwhelmed, resulting in lipid peroxidation and, ultimately, ferroptosis. In this review, we point out ferroptosis as an approach to consider in PDAC and propose that altering the cellular ROS balance by combining oxidizing agents or with inhibitors of the main cellular detoxifiers triggers ferroptosis in PDAC.

Exploring Sorafenib and Simvastatin Combination for Ferroptosis-Induced Cancer Treatment: Cytotoxicity Screening, In Vivo Efficacy, and Safety Assessment

Ferroptosis, a pathway dependent on oxygen and iron catalysts, holds promise as a therapeutic approach for cancer treatment due to its manageable regulation, direct control, and immunogenic properties. The sensitivity of cancer cells to ferroptosis induction varies based on their metabolic, genetic, and signalling pathways, prompting the use of combination therapy. In this study, we conducted a screening of drug combinations, including sorafenib (SOR) with simvastatin (SIM), phenethyl isothiocyanate, and trigonelline, in MDA-MB-231, A549, and HeLa cells to assess their cytotoxicity. The SOR-SIM combination exhibited a synergistic effect in MDA-MB-231, A549, and HeLa cells, with calculated CI values of ~ 0.66, 0.53, and 0.59, respectively. Furthermore, co-treatment with ferrostatin-1 resulted in a concentration-dependent increase in the IC50 values. Additionally, SOR + SIM demonstrated a significant reduction in GSH levels, an increase in MDA levels, and mitochondrial membrane depolarization across all three cell lines, indicating their ferroptosis inducing potential. In-vivo studies showed a significant reduction in tumor volume by 3.53-, 2.55-, and 1.47-fold compared to control, SIM, and SOR, respectively. Toxicity assessments revealed insignificant changes in biomarker levels and no observable deformations in isolated organs, except for erythrocyte shrinkage and membrane scrambling effects caused by the SOR + SIM combination. Overall, our findings highlight the potential of the SOR + SIM combination as an effective strategy for cancer treatment, emphasizing the importance of further research in targeted drug delivery systems to ensure its safety.

Ferroptosis-modulating small molecules for targeting drug-resistant cancer: Challenges and opportunities in manipulating redox signaling

Ferroptosis is an iron-dependent cell death program that is characterized by excessive lipid peroxidation. Triggering ferroptosis has been proposed as a promising strategy to fight cancer and overcome drug resistance in antitumor therapy. Understanding the molecular interactions and structural features of ferroptosis-inducing compounds might therefore open the door to efficient pharmacological strategies against aggressive, metastatic, and therapy-resistant cancer. We here summarize the molecular mechanisms and structural requirements of ferroptosis-inducing small molecules that target central players in ferroptosis. Focus is placed on (i) glutathione peroxidase (GPX) 4, the only GPX isoenzyme that detoxifies complex membrane-bound lipid hydroperoxides, (ii) the cystine/glutamate antiporter system Xc - that is central for glutathione regeneration, (iii) the redox-protective transcription factor nuclear factor erythroid 2-related factor (NRF2), and (iv) GPX4 repression in combination with induced heme degradation via heme oxygenase-1. We deduce common features for efficient ferroptotic activity and highlight challenges in drug development. Moreover, we critically discuss the potential of natural products as ferroptosis-inducing lead structures and provide a comprehensive overview of structurally diverse biogenic and bioinspired small molecules that trigger ferroptosis via iron oxidation, inhibition of the thioredoxin/thioredoxin reductase system or less defined modes of action.

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

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

Ferroptosis in gastrointestinal cancer: From mechanisms to implications

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

Diabetic Ferroptosis and Pancreatic Cancer: Foe or Friend?

Significance: Pancreatic cancer and diabetes have a reciprocal causation relationship. As a potential risk factor, diabetes increases morbidity and promotes pancreatic cancer progression. The main mechanisms include islet dysfunction-induced systemic metabolic disorder, pancreatic stellate cell activation, and immunosuppression. Ferroptosis is regarded as regulated cell death, which participates in chemotherapy resistance and is refractory to radiation therapy and immunotherapy. Diabetes-induced ferroptosis causes many complications, but the underlying mechanism of diabetes-related ferroptosis in pancreatic cancer has not been discussed. Recent Advances: Ferroptosis alleviates pancreatic intraepithelial neoplasia (PanIN) progression by activating chronic inflammation. The specific drugs that cause ferroptosis achieve tumor suppression by inducing lipid peroxidation. Ferroptosis plays pro and con roles in cancer. Both the ferroptosis inhibitor and inducer exhibit antitumor effects through killing cancer cells or directly affecting tumor growth. Diabetes-induced ferroptosis contributes to tumor cell death by different components, including tumor cells, fibroblasts, immune cells, and adipocytes. A better understanding of its role in modulating the tumor microenvironment will reveal diabetes-associated ferroptotic features in cancer development, which can be used to figure out possible treatment strategies for cancer patients with hyperglycemia. Critical Issues: We demonstrate the potential roles of diabetes-related ferroptosis in pancreatic cancer progression and discuss ferroptosis-related antitumor effects and therapeutics for pancreatic cancer treatment. Future Directions: Further studies are required to highlight mechanisms of diabetes-mediated ferroptosis in pancreatic cancer tumorigenesis and progression. The antitumor effects of ferroptosis regulators combined with chemotherapy, targeted therapy, or immunotherapy in diabetic patients should be investigated. We hope that pancreatic cancer patients with diabetes will benefit from ferroptosis-related therapies. Antioxid. Redox Signal. 37, 1206-1221.

Lipid metabolism in pancreatic cancer: emerging roles and potential targets

Pancreatic cancer is one of the most serious health issues in developed and developing countries, with a 5-year overall survival rate currently <9%. Patients typically present with advanced disease due to vague symptoms or lack of screening for early cancer detection. Surgical resection represents the only chance for cure, but treatment options are limited for advanced diseases, such as distant metastatic or locally progressive tumors. Although adjuvant chemotherapy has improved long-term outcomes in advanced cancer patients, its response rate is low. So, exploring other new treatments is urgent. In recent years, increasing evidence has shown that lipid metabolism can support tumorigenesis and disease progression as well as treatment resistance through enhanced lipid synthesis, storage, and catabolism. Therefore, a better understanding of lipid metabolism networks may provide novel and promising strategies for early diagnosis, prognosis estimation, and targeted therapy for pancreatic cancer patients. In this review, we first enumerate and discuss current knowledge about the advances made in understanding the regulation of lipid metabolism in pancreatic cancer. In addition, we summarize preclinical studies and clinical trials with drugs targeting lipid metabolic systems in pancreatic cancer. Finally, we highlight the challenges and opportunities for targeting lipid metabolism pathways through precision therapies in pancreatic cancer.

System Xc−/GSH/GPX4 axis: An important antioxidant system for the ferroptosis in drug-resistant solid tumor therapy

The activation of ferroptosis is a new effective way to treat drug-resistant solid tumors. Ferroptosis is an iron-mediated form of cell death caused by the accumulation of lipid peroxides. The intracellular imbalance between oxidant and antioxidant due to the abnormal expression of multiple redox active enzymes will promote the produce of reactive oxygen species (ROS). So far, a few pathways and regulators have been discovered to regulate ferroptosis. In particular, the cystine/glutamate antiporter (System Xc−), glutathione peroxidase 4 (GPX4) and glutathione (GSH) (System Xc−/GSH/GPX4 axis) plays a key role in preventing lipid peroxidation-mediated ferroptosis, because of which could be inhibited by blocking System Xc−/GSH/GPX4 axis. This review aims to present the current understanding of the mechanism of ferroptosis based on the System Xc−/GSH/GPX4 axis in the treatment of drug-resistant solid tumors.

The mechanism and progress of ferroptosis in pancreatic cancer

Pancreatic cancer is one of the deadliest cancers in the world, causing hundreds of thousands of deaths worldwide annually. Because of late diagnosis, rapid metastasis and drug resistance to chemotherapy, pancreatic cancer has a poor prognosis. Although the treatment of pancreatic cancer has made tremendous progress, the options for effective treatment are still limited, and new treatment methods are in crying needs to improve prognosis in clinic. Ferroptosis is an iron-dependent non-apoptotic cell death mode, which is mediated by lipid peroxidation and iron accumulation. Ferroptosis plays a momentous role in regulating different cancers in recent years, such as breast cancer, hepatocellular carcinoma, lung cancer and pancreatic cancer. In this present review, we elaborate on the regulatory mechanisms and signaling pathways of ferroptosis in pancreatic cancer, with the intention of delivering directions and new ideas for the treatment of pancreatic cancer.

A Two-Phase Approach to Fusicoccane Synthesis To Uncover a Compound That Reduces Tumourigenesis in Pancreatic Cancer Cells

Alterbrassicicene D (1) and 3(11)-epoxyhypoestenone (2) were synthesised via a two-phase approach featuring concise construction of the 5-8-5 tricyclic intermediate and a tandem base-mediated epoxide opening-transannular oxa-Michael addition cascade to forge the complex skeleton of 2. The route is scalable and we generated 15 g of the tricyclic intermediate in 8 steps from (R)-limonene and 720 mg of the penultimate bioactive intermediate in a protecting-group-free manner. Our synthesis enabled the structural determination of 2 and provided materials for preliminary anticancer evaluation. The penultimate intermediate showed therapeutic potential in terms of its ability to dramatically reduce the tumourigenic potential of PANC-1 pancreatic cancer cells according to a limiting dilution tumour-initiating assay. Our synthetic approach will facilitate unified access to naturally occurring fusicoccanes and their derivatives for anticancer evaluation.

Role of ferroptosis in gastrointestinal tumors: From mechanisms to therapies

Ferroptosis is an iron-dependent nonapoptotic regulated cell death, which is mainly caused by an abnormal increase in lipid oxygen free radicals and an imbalance in redox homeostasis. Recently, ferroptosis has been shown to have implications in various gastrointestinal cancers, such as gastric carcinoma, hepatocellular carcinoma, and pancreatic cancer. This review summarises the latest research on ferroptosis, its mechanism of action, and its role in the progression of different gastrointestinal tumors to provide more information regarding the prevention and treatment of these tumors.

Platelet-Vesicles-Encapsulated RSL-3 Enable Anti-Angiogenesis and Induce Ferroptosis to Inhibit Pancreatic Cancer Progress

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant cancers. It is characterized by stromal richness, lack of blood supply and special metabolic reprogramming in the tumor microenvironment, which is difficult to treat and easy to metastase. Great efforts have been made to develop new drugs which can pass through the stroma and are more effective than traditional chemotherapeutics, such as ferroptosis inducers-Erastin and RSL-3. As current anti-angiogenic therapy drugs alone are suboptimal for PDAC, novel vascular disruption agents in combination with ferroptosis inducers might provide a possible solution. Here, we designed human platelet vesicles (PVs) to camouflage RSL-3 to enhance drug uptake rate by tumor cells and circulation time in vivo, deteriorating the tumor vessels and resulting in tumor embolism to cut the nutrient supply as well as causing cell death due to excessive lipid peroxidation. The RSL-3@PVs can also cause the classic ferroptosis-related change of mitochondrial morphology, with changes in cellular redox levels. Besides that, RSL-3@PVs has been proved to have great biological safety profile in vitro and in vivo. This study demonstrates the promising potential of integrating PVs and RSL-3 as a combination therapy for improving the outcome of PDAC.

Persister cancer cells: Iron addiction and vulnerability to ferroptosis

Ferroptosis is a unique type of non-apoptotic cell death resulting from the unrestrained occurrence of peroxidized phospholipids, which are subject to iron-mediated production of lethal oxygen radicals. This cell death modality has been detected across many organisms, including in mammals, where it can be used as a defense mechanism against pathogens or even harnessed by T cells to sensitize tumor cells toward effective killing. Conversely, ferroptosis is considered one of the main cell death mechanisms promoting degenerative diseases. Emerging evidence suggests that ferroptosis represents a vulnerability in certain cancers. Here, we critically review recent advances linking ferroptosis vulnerabilities of dedifferentiating and persister cancer cells to the dependency of these cells on iron, a potential Achilles heel for small-molecule intervention. We provide a perspective on the mechanisms reliant on iron that contribute to the persister cancer cell state and how this dependency may be exploited for therapeutic benefits.

Ferroptosis in cancer and cancer immunotherapy

The hallmark of tumorigenesis is the successful circumvention of cell death regulation for achieving unlimited replication and immortality. Ferroptosis is a newly identified type of cell death dependent on lipid peroxidation which differs from classical programmed cell death in terms of morphology, physiology and biochemistry. The broad spectrum of injury and tumor tolerance are the main reasons for radiotherapy and chemotherapy failure. The effective rate of tumor immunotherapy as a new treatment method is less than 30%. Ferroptosis can be seen in radiotherapy, chemotherapy, and tumor immunotherapy; therefore, ferroptosis activation may be a potential strategy to overcome the drug resistance mechanism of traditional cancer treatments. In this review, the characteristics and causes of cell death by lipid peroxidation in ferroptosis are briefly described. In addition, the three metabolic regulations of ferroptosis and its crosstalk with classical signaling pathways are summarized. Collectively, these findings suggest the vital role of ferroptosis in immunotherapy based on the interaction of ferroptosis with tumor immunotherapy, chemotherapy and radiotherapy, thus, indicating the remarkable potential of ferroptosis in cancer treatment.

Emerging Mechanisms and Disease Implications of Ferroptosis: Potential Applications of Natural Products

Ferroptosis, a newly discovered form of regulatory cell death (RCD), has been demonstrated to be distinct from other types of RCD, such as apoptosis, necroptosis, and autophagy. Ferroptosis is characterized by iron-dependent lipid peroxidation and oxidative perturbation, and is inhibited by iron chelators and lipophilic antioxidants. This process is regulated by specific pathways and is implicated in diverse biological contexts, mainly including iron homeostasis, lipid metabolism, and glutathione metabolism. A large body of evidence suggests that ferroptosis is interrelated with various physiological and pathological processes, including tumor progression (neuro)degenerative diseases, and hepatic and renal failure. There is an urgent need for the discovery of novel effective ferroptosis-modulating compounds, even though some experimental reagents and approved clinical drugs have been well documented to have anti- or pro-ferroptotic properties. This review outlines recent advances in molecular mechanisms of the ferroptotic death process and discusses its multiple roles in diverse pathophysiological contexts. Furthermore, we summarize chemical compounds and natural products, that act as inducers or inhibitors of ferroptosis in the prevention and treatment of various diseases. Herein, it is particularly highlighted that natural products show promising prospects in ferroptosis-associated (adjuvant) therapy with unique advantages of having multiple components, multiple biotargets and slight side effects.

Molecular regulatory mechanism of ferroptosis and its role in gastrointestinal oncology: Progress and updates

Gastrointestinal (GI) tumors, including liver, pancreatic, gastric, and colorectal cancers, have a high incidence rate and low survival rate due to the lack of effective therapeutic methods and frequent relapses. Surgery and postoperative chemoradiotherapy have largely reduced the fatality rates for most GI tumors, but these therapeutic approaches result in poor prognoses due to severe adverse reactions and the development of drug resistance. Recent studies have shown that ferroptosis plays an important role in the onset and progression of GI tumors. Ferroptosis is a new non-apoptotic form of cell death, which is iron-dependent, non-apoptotic cell death characterized by the accumulation of lipid reactive oxygen species (ROS). The activation of ferroptosis can lead to tumor cell death. Thus, regulating ferroptosis in tumor cells may become a new therapeutic approach for tumors, making it become a research hotspot. Current studies suggest that ferroptosis is mainly triggered by the accumulation of lipid ROS. Furthermore, several studies have indicated that ferroptosis may be a new approach for the treatment of GI tumors. Here, we review current research progress on the mechanism of ferroptosis, current inducers and inhibitors of ferroptosis, and the role of ferroptosis in GI tumors to propose new methods for the treatment of such tumors.

Abnormal Iron and Lipid Metabolism Mediated Ferroptosis in Kidney Diseases and Its Therapeutic Potential

Ferroptosis is a newly identified form of regulated cell death driven by iron-dependent phospholipid peroxidation and oxidative stress. Ferroptosis has distinct biological and morphology characteristics, such as shrunken mitochondria when compared to other known regulated cell deaths. The regulation of ferroptosis includes different molecular mechanisms and multiple cellular metabolic pathways, including glutathione/glutathione peroxidase 4(GPX4) signaling pathways, which are involved in the amino acid metabolism and the activation of GPX4; iron metabolic signaling pathways, which are involved in the regulation of iron import/export and the storage/release of intracellular iron through iron-regulatory proteins (IRPs), and lipid metabolic signaling pathways, which are involved in the metabolism of unsaturated fatty acids in cell membranes. Ferroptosis plays an essential role in the pathology of various kidneys diseases, including acute kidney injury (AKI), chronic kidney disease (CKD), autosomal dominant polycystic kidney disease (ADPKD), and renal cell carcinoma (RCC). Targeting ferroptosis with its inducers/initiators and inhibitors can modulate the progression of kidney diseases in animal models. In this review, we discuss the characteristics of ferroptosis and the ferroptosis-based mechanisms, highlighting the potential role of the main ferroptosis-associated metabolic pathways in the treatment and prevention of various kidney diseases.

The Function of cGAS-STING Pathway in Treatment of Pancreatic Cancer

The activation of stimulator of interferon genes (STING) signalling pathway has been suggested to promote the immune responses against malignancy. STING is activated in response to the detection of cytosolic DNA and can induce type I interferons and link innate immunity with the adaptive immune system. Due to accretive evidence demonstrating that the STING pathway regulates the immune cells of the tumor microenvironment (TME), STING as a cancer biotherapy has attracted considerable attention. Pancreatic cancer, with a highly immunosuppressive TME, remains fatal cancer. STING has been applied to the treatment of pancreatic cancer through distinct strategies. This review reveals the role of STING signalling on pancreatic tumors and other diseases related to the pancreas. We then discuss new advances of STING in either monotherapy or combination methods for pancreatic cancer immunotherapy.

The Regulatory Effects and the Signaling Pathways of Natural Bioactive Compounds on Ferroptosis

Natural bioactive compounds abundantly presented in foods and medicinal plants have recently received a remarkable attention because of their various biological activities and minimal toxicity. In recent years, many natural compounds appear to offer significant effects in the regulation of ferroptosis. Ferroptosis is the forefront of international scientific research which has been exponential growth since the term was coined. This type of regulated cell death is driven by iron-dependent phospholipid peroxidation. Recent studies have shown that numerous organ injuries and pathophysiological processes of many diseases are driven by ferroptosis, such as cancer, arteriosclerosis, neurodegenerative disease, diabetes, ischemia-reperfusion injury and acute renal failure. It is reported that the initiation and inhibition of ferroptosis plays a pivotal role in lipid peroxidation, organ damage, neurodegeneration and cancer growth and progression. Recently, many natural phytochemicals extracted from edible plants have been demonstrated to be novel ferroptosis regulators and have the potential to treat ferroptosis-related diseases. This review provides an updated overview on the role of natural bioactive compounds and the potential signaling pathways in the regulation of ferroptosis.

Association of Diabetes Mellitus and Alcohol Abuse with Cancer: Molecular Mechanisms and Clinical Significance

Diabetes mellitus (DM), one of the metabolic diseases which is characterized by sustained hyperglycemia, is a life-threatening disease. The global prevalence of DM is on the rise, mainly in low- and middle-income countries. Diabetes is a major cause of blindness, heart attacks, kidney failure, stroke, and lower limb amputation. Type 2 diabetes mellitus (T2DM) is a form of diabetes that is characterized by high blood sugar and insulin resistance. T2DM can be prevented or delayed by a healthy diet, regular physical activity, maintaining normal body weight, and avoiding alcohol and tobacco use. Ethanol and its metabolites can cause differentiation defects in stem cells and promote inflammatory injury and carcinogenesis in several tissues. Recent studies have suggested that diabetes can be treated, and its consequences can be avoided or delayed with proper management. DM has a greater risk for several cancers, such as breast, colorectal, endometrial, pancreatic, gallbladder, renal, and liver cancer. The incidence of cancer is significantly higher in patients with DM than in those without DM. In addition to DM, alcohol abuse is also a risk factor for many cancers. We present a review of the recent studies investigating the association of both DM and alcohol abuse with cancer incidence.

Regulation and function of autophagy in pancreatic cancer

Oncogenic KRAS mutation-driven pancreatic ductal adenocarcinoma is currently the fourth-leading cause of cancer-related deaths in the United States. Macroautophagy (hereafter "autophagy") is one of the lysosome-dependent degradation systems that can remove abnormal proteins, damaged organelles, or invading pathogens by activating dynamic membrane structures (e.g., phagophores, autophagosomes, and autolysosomes). Impaired autophagy (including excessive activation and defects) is a pathological feature of human diseases, including pancreatic cancer. However, dysfunctional autophagy has many types and plays a complex role in pancreatic tumor biology, depending on various factors, such as tumor stage, microenvironment, immunometabolic state, and death signals. As a modulator connecting various cellular events, pharmacological targeting of nonselective autophagy may lead to both good and bad therapeutic effects. In contrast, targeting selective autophagy could reduce potential side effects of the drugs used. In this review, we describe the advances and challenges of autophagy in the development and therapy of pancreatic cancer.Abbreviations: AMPK: AMP-activated protein kinase; CQ: chloroquine; csc: cancer stem cells; DAMP: danger/damage-associated molecular pattern; EMT: epithelial-mesenchymal transition; lncRNA: long noncoding RNA; MIR: microRNA; PanIN: pancreatic intraepithelial neoplasia; PDAC: pancreatic ductal adenocarcinoma; PtdIns3K: phosphatidylinositol 3-kinase; SNARE: soluble NSF attachment protein receptor; UPS: ubiquitin-proteasome system.

NUPR1 inhibitor ZZW-115 induces ferroptosis in a mitochondria-dependent manner

Ferroptosis is an iron-dependent cell death characterized by the accumulation of hydroperoxided phospholipids. Here, we report that the NUPR1 inhibitor ZZW-115 induces ROS accumulation followed by a ferroptotic cell death, which could be prevented by ferrostatin-1 (Fer-1) and ROS-scavenging agents. The ferroptotic activity can be improved by inhibiting antioxidant factors in pancreatic ductal adenocarcinoma (PDAC)- and hepatocellular carcinoma (HCC)-derived cells. In addition, ZZW-115-treatment increases the accumulation of hydroperoxided lipids in these cells. We also found that a loss of activity and strong deregulation of key enzymes involved in the GSH- and GPX-dependent antioxidant systems upon ZZW-115 treatment. These results have been validated in xenografts induced with PDAC- and HCC-derived cells in nude mice during the treatment with ZZW-115. More importantly, we demonstrate that ZZW-115-induced mitochondrial morphological changes, compatible with the ferroptotic process, as well as mitochondrial network disorganization and strong mitochondrial metabolic dysfunction, which are rescued by both Fer-1 and N-acetylcysteine (NAC). Of note, the expression of TFAM, a key regulator of mitochondrial biogenesis, is downregulated by ZZW-115. Forced expression of TFAM is able to rescue morphological and functional mitochondrial alterations, ROS production, and cell death induced by ZZW-115 or genetic inhibition of NUPR1. Altogether, these results demonstrate that the mitochondrial cell death mediated by NUPR1 inhibitor ZZW-115 is fully rescued by Fer-1 but also via TFAM complementation. In conclusion, TFAM could be considered as an antagonist of the ferroptotic cell death.

Ferroptosis and its emerging role in tumor

Ferroptosis is a novel form of programmed cell death characterized by iron-dependent lipid peroxidation accumulation. It is morphologically, biochemically, and genetically distinct from other known cell death, such as apoptosis, necrosis, and pyroptosis. Its regulatory mechanisms include iron metabolism, fatty acid metabolism, mitochondrial respiration, and antioxidative systems eliminating lipid peroxidation, such as glutathione synthesis, selenium-dependent glutathione peroxidase 4, and ubiquinone. The disruption of cellular redox systems causes damage to the cellular membrane leading to ferroptotic cell death. Recent studies have shown that numerous pathological diseases, like tumors, neurodegenerative disorders, and ischemia-reperfusion injury are associated with ferroptosis. As such, pharmacological regulation of ferroptosis either by activation or by suppression will provide a vast potential for treatments of relevant diseases. This review will discuss the advanced progress in ferroptosis and its regulatory mechanisms from both the antioxidative and oxidative sides. In addition, the roles of ferroptosis in various tumorigenesis, development, and therapeutic strategies will be addressed, particularly to chemotherapy and immunotherapy, as well as the discoveries from Traditional Chinese Medicine. This review will lead us to have a comprehensive understanding of the future exploration of ferroptosis and cancer therapy.

Mitochondrial regulation of ferroptosis

Ferroptosis is a form of iron-dependent regulated cell death driven by uncontrolled lipid peroxidation. Mitochondria are double-membrane organelles that have essential roles in energy production, cellular metabolism, and cell death regulation. However, their role in ferroptosis has been unclear and somewhat controversial. In this Perspective, I summarize the diverse metabolic processes in mitochondria that actively drive ferroptosis, discuss recently discovered mitochondria-localized defense systems that detoxify mitochondrial lipid peroxides and protect against ferroptosis, present new evidence for the roles of mitochondria in regulating ferroptosis, and outline outstanding questions on this fascinating topic for future investigations. An in-depth understanding of mitochondria functions in ferroptosis will have important implications for both fundamental cell biology and disease treatment.

Targeting ferroptosis in osteosarcoma

Osteosarcoma (OS) is the most common primary bone tumour in children and adolescents, with high degree of malignancy and an extremely poor prognosis. Ferroptosis, a non-traditional mode of regulated cell death (RCD) characterised by iron-dependent accumulation of lipid reactive oxygen species (ROS), is closely associated with a variety of cancers. It has been demonstrated that ferroptosis can regulate OS progression and exert an essential role in the treatment of OS, which is potentially of great value. By targeting ferroptosis in OS, the present review article summarises the relevant mechanisms and therapeutic applications along with discussing current limitations and future directions, which may provide a new strategy for the treatment of OS.

Development and validation of a ferroptosis-related prognostic model in pancreatic cancer

BACKGROUND

The purpose of this study was to identify ferroptosis-related genes (FRGs) associated with the prognosis of pancreatic cancer and to construct a prognostic model based on FRGs.

METHODS

Based on pancreatic cancer data obtained from The Cancer Genome Atlas database, we established a prognostic model from 232 FRGs. A nomogram was constructed by combining the prognostic model and clinicopathological features. Gene Expression Omnibus datasets and tissue samples obtained from our center were utilized to validate the model. The relationship between risk score and immune cell infiltration was explored by CIBERSORT and TIMER.

RESULTS

The prognostic model was established based on four FRGs (ENPP2, ATG4D, SLC2A1 and MAP3K5), and the risk score was demonstrated to be an independent risk factor in pancreatic cancer (HR 1.648, 95% CI 1.335-2.035, p < 0.001). Based on the median risk score, patients were divided into a high-risk group and a low-risk group. The low-risk group had a better prognosis than the high-risk group. In the high-risk group, patients treated with chemotherapy had a better prognosis. The nomogram showed that the model was the most important element. Gene set enrichment analysis identified three key pathways, namely, TGFβ signaling, HIF signaling pathway and the adherens junction. The prognostic model may be associated with infiltration of immune cells such as M0 macrophages, M1 macrophages, CD4 + T cells and CD8 + T cells.

CONCLUSION

The ferroptosis-related prognostic model can be employed to predict the prognosis of pancreatic cancer. Ferroptosis is an important marker, and immunotherapy may be a potential therapeutic target for pancreatic cancer.

Targeting ferroptosis in pancreatic cancer: a double-edged sword

Pancreatic ductal adenocarcinoma (PDAC) remains an aggressive malignancy with a 5-year survival rate below 10%. Its unique genetic makeup and tumor microenvironment produce a lack of response to current treatments, including chemotherapy, radiotherapy, and immunotherapy. Recent preclinical studies have revealed that ferroptosis, an iron-dependent form of nonapoptotic cell death driven by unrestricted lipid peroxidation, may be an attractive therapeutic goal in PDAC. Understanding the dual role of ferroptotic cell death in both promoting and suppressing tumor immunity, as well as its integrated regulatory mechanisms and signaling pathways, may lead to more effective treatment designs for clinical trials of PDAC and may minimize or delay the emergence of drug resistance or side effects.

Heme Oxygenase-1 Inhibition Potentiates the Effects of Nab-Paclitaxel-Gemcitabine and Modulates the Tumor Microenvironment in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with a poor prognosis. Tumor hypoxia plays an active role in promoting tumor progression, malignancy, and resistance to therapy in PDAC. We present evidence that nab-paclitaxel-gemcitabine (NPG) and/or a hypoxic tumor microenvironment (TME) up-regulate heme oxygenase-1 (HO-1), providing a survival advantage for tumors. Using PDAC cells in vitro and a PDAC mouse model, we found that NPG chemotherapy up-regulated expression of HO-1 in PDAC cells and increased its nuclear translocation. Inhibition of HO-1 with ZnPP and SnPP sensitized PDAC cells to NPG-induced cytotoxicity (p < 0.05) and increased apoptosis (p < 0.05). Additionally, HO-1 expression was increased in gemcitabine-resistant PDAC cells (p < 0.05), and HO-1 inhibition increased GEM-resistant PDAC sensitivity to NPG (p < 0.05). NPG combined with HO-1 inhibitor inhibited tumor size in an orthotopic model. In parallel, HO-1 inhibition abrogated the influx of macrophages and FoxP3+ cells, while increasing the proportion of CD8+ infiltration in the pancreatic tumors. These effects were mediated primarily by reducing expression of the immunosuppressive cytokine IL-10.

Mechanistic connections between mitochondrial biology and regulated cell death

The ancient, dynamic, and multifaceted functions of the mitochondrial network are essential for organismal homeostasis and contribute to numerous human diseases. As central hubs for metabolism, ion transport, and multiple macromolecular synthesis pathways, mitochondria establish and control extensive signaling networks to ensure cellular survival. In this review, we explore how these same mitochondrial functions also participate in the control of regulated cell death (RCD). We discuss the complementary essential mitochondrial functions as compartments that participate in the production and presentation of key molecules and platforms that actively enable, initiate, and execute RCD.

Regulation of ferroptosis by bioactive phytochemicals: Implications for medical nutritional therapy

Ferroptosis is an iron- and lipotoxicity-dependent regulated cell death that has been implicated in various diseases, such as cancer, neurodegeneration and stroke. The biosynthesis of phospholipids, coenzyme Q₁₀, and glutathione, and the metabolism of iron, amino acids and polyunsaturated fatty acid, are tightly associated with cellular sensitivity to ferroptosis. Up to now, only limited drugs targeting ferroptosis have been documented and exploring novel effective ferroptosis-modulating compound is needed. Natural bioactive products are conventional resources for drug discovery, and some of them have been clinically used against cancers and neurodegenerative diseases as dietary supplements or pharmaceutic agents. Notably, increasing evidence demonstrates that natural compounds, such as saponins, flavonoids and isothiocyanates, can either induce or inhibit ferroptosis, further expanding their therapeutic potentials. In this review, we highlight current advances of the emerging molecular mechanisms and disease relevance of ferroptosis. We also systematically summarize the regulatory effects of natural phytochemicals on ferroptosis, and clearly indicate that saponins, terpenoids and alkaloids induce ROS- and ferritinophagy-dependent ferroptosis, whereas flavonoids and polyphenols modulate iron metabolism and nuclear factor erythroid 2-related factor 2 (NRF2) signaling to inhibit ferroptosis. Finally, we explore their clinical applications in ferroptosis-related diseases, which may facilitate the development of their dietary usages as nutraceuticals.

Caspase-Independent Regulated Necrosis Pathways as Potential Targets in Cancer Management

Regulated necrosis is an emerging type of cell death independent of caspase. Recently, with increasing findings of regulated necrosis in the field of biochemistry and genetics, the underlying molecular mechanisms and signaling pathways of regulated necrosis are gradually understood. Nowadays, there are several modes of regulated necrosis that are tightly related to cancer initiation and development, including necroptosis, ferroptosis, parthanatos, pyroptosis, and so on. What’s more, accumulating evidence shows that various compounds can exhibit the anti-cancer effect via inducing regulated necrosis in cancer cells, which indicates that caspase-independent regulated necrosis pathways are potential targets in cancer management. In this review, we expand the molecular mechanisms as well as signaling pathways of multiple modes of regulated necrosis. We also elaborate on the roles they play in tumorigenesis and discuss how each of the regulated necrosis pathways could be therapeutically targeted.

Application of natural products for inducing ferroptosis in tumor cells

Ferroptosis is a regulated cell death pathway based on the deposition of lipid-based reactive oxygen species (L-ROS) in the presence of iron ions. The term was first coined in 2012 by Dixon. Decreased glutathione (GSH) synthesis and low glutathione-dependent antioxidant peroxidase 4 (GPX4) activity are the major causes of ferroptosis. Sensitivity to ferroptosis for example in tumor cells may be further enhanced by high cellular iron concentrations and/or high p53 levels. Therefore, driving ferroptosis in tumor cells could be a new way to treat tumors. Thus far, natural products have played considerable roles in antitumor research and treatment, and some drugs, such as paclitaxel, have proven beneficial in many cancer patients. According to current research, natural products can induce ferroptosis when used alone or in conjunction with other cancer therapies. This review mainly elaborates the main mechanism of ferroptosis and the regulating effects of some natural products on ferroptosis, aiming to create a new space for the research and development of novel anticancer drugs.

Targeting ferroptosis in breast cancer

Ferroptosis is a recently discovered distinct type of regulated cell death caused by the accumulation of lipid-based ROS. Metabolism and expression of specific genes affect the occurrence of ferroptosis, making it a promising therapeutic target to manage cancer. Here, we describe the current status of ferroptosis studies in breast cancer and trace the key regulators of ferroptosis back to previous studies. We also compare ferroptosis to common regulated cell death patterns and discuss the sensitivity to ferroptosis in different subtypes of breast cancer. We propose that viewing ferroptosis-related studies from a historical angle will accelerate the development of ferroptosis-based biomarkers and therapeutic strategies in breast cancer.

The multifaceted role of reactive oxygen species in tumorigenesis

Redox homeostasis is an essential requirement of the biological systems for performing various normal cellular functions including cellular growth, differentiation, senescence, survival and aging in humans. The changes in the basal levels of reactive oxygen species (ROS) are detrimental to cells and often lead to several disease conditions including cardiovascular, neurological, diabetes and cancer. During the last two decades, substantial research has been done which clearly suggests that ROS are essential for the initiation, progression, angiogenesis as well as metastasis of cancer in several ways. During the last two decades, the potential of dysregulated ROS to enhance tumor formation through the activation of various oncogenic signaling pathways, DNA mutations, immune escape, tumor microenvironment, metastasis, angiogenesis and extension of telomere has been discovered. At present, surgery followed by chemotherapy and/or radiotherapy is the major therapeutic modality for treating patients with either early or advanced stages of cancer. However, the majority of patients relapse or did not respond to initial treatment. One of the reasons for recurrence/relapse is the altered levels of ROS in tumor cells as well as in cancer-initiating stem cells. One of the critical issues is targeting the intracellular/extracellular ROS for significant antitumor response and relapse-free survival. Indeed, a large number of FDA-approved anticancer drugs are efficient to eliminate cancer cells and drug resistance by increasing ROS production. Thus, the modulation of oxidative stress response might represent a potential approach to eradicate cancer in combination with FDA-approved chemotherapies, radiotherapies as well as immunotherapies.