SIRT3 inhibits gallbladder cancer by induction of AKT-dependent ferroptosis and blockade of epithelial-mesenchymal transition

Ferroptosis, a therapeutic target for cardiovascular diseases, neurodegenerative diseases and cancer

The identification of ferroptosis represents a pivotal advancement in the field of cell death research, revealing an entirely novel mechanism of cellular demise and offering new insights into the initiation, progression, and therapeutic management of various diseases. Ferroptosis is predominantly induced by intracellular iron accumulation, lipid peroxidation, or impairments in the antioxidant defense system, culminating in membrane rupture and consequent cell death. Studies have associated ferroptosis with a wide range of diseases, and by enhancing our comprehension of its underlying mechanisms, we can formulate innovative therapeutic strategies, thereby providing renewed hope for patients.

The Expression of SIRT3 in Endometrial Carcinoma and Its Effect on Promoting Apoptosis of Ishikawa Cells

Endometrial cancer (EC) is one of the three most common malignancies of the female reproductive system. SIRT3 is an NAD+-dependent protein deacetylase that maintains the stability of the intracellular environment. This study aims to investigate the mechanism of SIRT3 in regulating apoptosis in endometrial cancer and further reveal the role of SIRT3 in endometrial cancer. Differential expression of SIRT3 in tumors was analyzed by GEPIA using TCGA database data. Meanwhile, mRNA and protein expression levels of SIRT3 in tissues and cells were examined using RT-qPCR, Western Blot, and immunohistochemistry. The expression of SIRT3 after estradiol (E2) stimulation of Ishikawa cells was detected using RT-qPCR and Western Blot techniques. The effect of transfection after SIRT3 knockdown and overexpression was verified using RT-qPCR and Western Blot. Flow cytometry and TUNEL assay were used to detect the effect of SIRT3 on apoptosis. Reactive oxygen species (ROS) was used to detect the effect of SIRT3 on the level of oxidative stress in cells. The expression of apoptotic protein (BAX, cleaved-Caspase 3) and autophagy protein (cyto C and LC3A) were detected in transfected Ishikawa cell. Differences analysis of TCGA database data showed that the expression of SIRT3 in EC was significantly lower than that in normal endometrial tissue. The mRNA and protein levels of SIRT3 were significantly lower in EC tissues or cells than normal controls. E2 stimulation in Ishikawa cells resulted in the down-regulation of SIRT3 expression. After transfection, SIRT3 promoted the apoptosis of Ishikawa cells and attenuated the levels of ROS. Overexpression of SIRT3 promoted apoptosis and autophagy-related proteins. Thus, high expression of SIRT3 inhibits the development of EC whereas low expression of SIRT3 may promote the progression of EC, which provides a new direction for studying the treatment of EC.

Decoding ferroptosis: transforming orthopedic disease management

As a mechanism of cell death, ferroptosis has gained popularity since 2012. The process is distinguished by iron toxicity and phospholipid accumulation, in contrast to autophagy, apoptosis, and other cell death mechanisms. It is implicated in the advancement of multiple diseases across the body. Researchers currently know that osteosarcoma, osteoporosis, and other orthopedic disorders are caused by NRF2, GPX4, and other ferroptosis star proteins. The effective relief of osteoarthritis symptoms from deterioration has been confirmed by clinical treatment with multiple ferroptosis inhibitors. At the same time, it should be reminded that the mechanisms involved in ferroptosis that regulate orthopedic diseases are not currently understood. In this manuscript, we present the discovery process of ferroptosis, the mechanisms involved in ferroptosis, and the role of ferroptosis in a variety of orthopedic diseases. We expect that this manuscript can provide a new perspective on clinical diagnosis and treatment of related diseases.

Ferroptosis: mechanisms and therapeutic targets

Ferroptosis is a nonapoptotic form of cell death characterized by iron-dependent lipid peroxidation in membrane phospholipids. Since its identification in 2012, extensive research has unveiled its involvement in the pathophysiology of numerous diseases, including cancers, neurodegenerative disorders, organ injuries, infectious diseases, autoimmune conditions, metabolic disorders, and skin diseases. Oxidizable lipids, overload iron, and compromised antioxidant systems are known as critical prerequisites for driving overwhelming lipid peroxidation, ultimately leading to plasma membrane rupture and ferroptotic cell death. However, the precise regulatory networks governing ferroptosis and ferroptosis-targeted therapy in these diseases remain largely undefined, hindering the development of pharmacological agonists and antagonists. In this review, we first elucidate core mechanisms of ferroptosis and summarize its epigenetic modifications (e.g., histone modifications, DNA methylation, noncoding RNAs, and N6-methyladenosine modification) and nonepigenetic modifications (e.g., genetic mutations, transcriptional regulation, and posttranslational modifications). We then discuss the association between ferroptosis and disease pathogenesis and explore therapeutic approaches for targeting ferroptosis. We also introduce potential clinical monitoring strategies for ferroptosis. Finally, we put forward several unresolved issues in which progress is needed to better understand ferroptosis. We hope this review will offer promise for the clinical application of ferroptosis-targeted therapies in the context of human health and disease.

The role of histone post-translational modifications in cancer and cancer immunity: functions, mechanisms and therapeutic implications

Histones play crucial roles in both promoting and repressing gene expression, primarily regulated through post-translational modifications (PTMs) at specific amino acid residues. Histone PTMs, including methylation, acetylation, ubiquitination, phosphorylation, lactylation, butyrylation, and propionylation, act as important epigenetic markers. These modifications influence not only chromatin compaction but also gene expression. Their importance extends to the treatment and prevention of various human diseases, particularly cancer, due to their involvement in key cellular processes. Abnormal histone modifications and the enzymes responsible for these alterations often serve as critical drivers in tumor cell proliferation, invasion, apoptosis, and stemness. This review introduces key histone PTMs and the enzymes responsible for these modifications, examining their impact on tumorigenesis and cancer progression. Furthermore, it explores therapeutic strategies targeting histone PTMs and offers recommendations for identifying new potential therapeutic targets.

Iron homeostasis and ferroptosis in human diseases: mechanisms and therapeutic prospects

Iron, an essential mineral in the body, is involved in numerous physiological processes, making the maintenance of iron homeostasis crucial for overall health. Both iron overload and deficiency can cause various disorders and human diseases. Ferroptosis, a form of cell death dependent on iron, is characterized by the extensive peroxidation of lipids. Unlike other kinds of classical unprogrammed cell death, ferroptosis is primarily linked to disruptions in iron metabolism, lipid peroxidation, and antioxidant system imbalance. Ferroptosis is regulated through transcription, translation, and post-translational modifications, which affect cellular sensitivity to ferroptosis. Over the past decade or so, numerous diseases have been linked to ferroptosis as part of their etiology, including cancers, metabolic disorders, autoimmune diseases, central nervous system diseases, cardiovascular diseases, and musculoskeletal diseases. Ferroptosis-related proteins have become attractive targets for many major human diseases that are currently incurable, and some ferroptosis regulators have shown therapeutic effects in clinical trials although further validation of their clinical potential is needed. Therefore, in-depth analysis of ferroptosis and its potential molecular mechanisms in human diseases may offer additional strategies for clinical prevention and treatment. In this review, we discuss the physiological significance of iron homeostasis in the body, the potential contribution of ferroptosis to the etiology and development of human diseases, along with the evidence supporting targeting ferroptosis as a therapeutic approach. Importantly, we evaluate recent potential therapeutic targets and promising interventions, providing guidance for future targeted treatment therapies against human diseases.

Chinese national clinical practice guideline on diagnosis and treatment of biliary tract cancers

BACKGROUND

Biliary tract carcinoma (BTC) is relatively rare and comprises a spectrum of invasive tumors arising from the biliary tree. The prognosis is extremely poor. The incidence of BTC is relatively high in Asian countries, and a high number of cases are diagnosed annually in China owing to the large population. Therefore, it is necessary to clarify the epidemiology and high-risk factors for BTC in China. The signs associated with BTC are complex, often require collaborative treatment from surgeons, endoscopists, oncologists, and radiation therapists. Thus, it is necessary to develop a comprehensive Chinese guideline for BTC.

METHODS

This clinical practice guideline (CPG) was developed following the process recommended by the World Health Organization. The Grading of Recommendations Assessment, Development, and Evaluation approach was used to assess the certainty of evidence and make recommendations. The full CPG report was reviewed by external guideline methodologists and clinicians with no direct involvement in the development of this CPG. Two guideline reporting checklists have been adhered to: Appraisal of Guidelines for Research and Evaluation (AGREE) and Reporting Items for practice Guidelines in Healthcare (RIGHT).

RESULTS

The guideline development group, which comprised 85 multidisciplinary clinical experts across China. After a controversies conference, 17 clinical questions concerning the prevention, diagnosis, and treatment of BTC were proposed. Additionally, detailed descriptions of the surgical principles, perioperative management, chemotherapy, immunotherapy, targeted therapy, radiotherapy, and endoscopic management were proposed.

CONCLUSIONS

The guideline development group created a comprehensive Chinese guideline for the diagnosis and treatment of BTC, covering various aspects of epidemiology, diagnosis, and treatment. The 17 clinical questions have important reference value for the management of BTC.

Phosphatase LHPP confers prostate cancer ferroptosis activation by modulating the AKT-SKP2-ACSL4 pathway

LHPP, a novel, recognized tumor suppressor, exerts a critical influence on the regulation of tumor cell proliferation and survival by modulating various signaling pathways with its phosphatase activity. Here, we unveil a robust correlation between reduced LHPP expression and adverse prognosis in prostate cancer. We demonstrate that LHPP interacts with AKT, thereby dampening AKT phosphorylation and subsequently inhibiting ACSL4 phosphorylation at the T624 site. This interaction impedes phosphorylation-dependent ubiquitination, thwarting SKP2 from recognizing and binding to ACSL4 at the K621 site. As a result, ACSL4 is spared from lysosomal degradation, leading to its accumulation and the promotion of lipid peroxidation, and ferroptosis. Moreover, our findings reveal that Panobinostat, a potent histone-deacetylase inhibitor, intricately regulates LHPP expression at multiple levels through the inhibition of HDAC3. This complex modulation enhances the ferroptosis pathway, offering a novel mechanism for curtailing the growth of prostate tumors and highlighting its significant translational potential for clinical application.

CircEZH2 promotes gallbladder cancer progression and lipid metabolism reprogramming through the miR-556-5p/SCD1 axis

Gallbladder cancer (GBC) is characterized by a high degree of malignancy and a poor prognosis. This study revealed that circEZH2 was frequently upregulated in GBC tissues and correlated with advanced tumor-node-metastasis (TNM) stage in GBC patients. In vitro and in vivo experiments confirmed that circEZH2 promoted the proliferation and inhibited the ferroptosis of GBC. Besides, this study discovered that circEZH2 regulated lipid metabolism reprogramming in GBC cells. Mechanistically, circEZH2 promotes SCD1 expression by sponging miR-556-5p in GBC cells. In addition, IGF2BP2 enhances the stability of circEZH2 in an m6A-dependent manner, while circEZH2 suppresses the ubiquitination and degradation of IGF2BP2 by binding to IGF2BP2. Taken together, our findings indicated that circEZH2, upregulated via a positive feedback loop between circEZH2 and IGF2BP2, promotes GBC progression and lipid metabolism reprogramming through the miR-556-5p/SCD1 axis in GBC. circEZH2 may serve as a potential therapeutic target for GBC.

SOAT1 in gallbladder cancer: Clinicopathological significance and avasimibe therapeutics

The aim of this investigation was to evaluate the differential expression of the sterol O-acyltransferase 1 (SOAT1) protein in gallbladder cancer tissues and cells, investigate the impact of Avastin on the proliferation, migration, invasion capabilities of gallbladder cancer cells, and its potential to induce cell apoptosis. Immunohistochemical analysis of samples from 145 gallbladder cancer patients was conducted, along with analysis of SOAT1 protein, mRNA expression levels, and cholesterol content in gallbladder cancer cell lines SGC-996, NOZ, and gallbladder cancer (GBC)-SD using Western blot and q-PCR techniques. Furthermore, the effects of Avastin on the proliferation, migration, and invasion capabilities of these gallbladder cancer cell lines were studied, and its ability to induce cell apoptosis was evaluated using flow cytometry, Western blot, and immunohistochemical methods. Additionally, gene expression and pathway analysis were performed, and the synergistic therapeutic effects of Avastin combined with gemcitabine were tested in a gallbladder cancer xenograft model. The study found that SOAT1 expression was significantly upregulated in GBC tissues and positively correlated with lymph node metastasis and TNM staging. In vitro experiments demonstrated that Avastin significantly inhibited the proliferation, migration, and invasion capabilities of SGC-996 and GBC-SD cell lines and induced apoptosis. RNA sequencing analysis revealed multiple differentially expressed genes in cells treated with Avastin, primarily enriched in biological pathways such as signaling transduction, malignant tumors, and the immune system. In vivo, experiments confirmed that Avastin could effectively suppress tumor growth in a gallbladder cancer xenograft model and enhanced the treatment efficacy when used in combination with gemcitabine. Overall, these findings provide new insights and strategies for targeted therapy in gallbladder cancer.

Capsaicin Enhanced the Efficacy of Photodynamic Therapy Against Osteosarcoma via a Pro-Death Strategy by Inducing Ferroptosis and Alleviating Hypoxia

Ferroptosis, a novel form of nonapoptotic cell death, can effectively enhance photodynamic therapy (PDT) performance by disrupting intracellular redox homeostasis and promoting apoptosis. However, the extremely hypoxic tumor microenvironment (TME) together with highly expressed hypoxia-inducible factor-1α (HIF-1α) presents a considerable challenge for clinical PDT against osteosarcoma (OS). Hence, an innovative nanoplatform that enhances antitumor PDT by inducing ferroptosis and alleviating hypoxia is fabricated. Capsaicin (CAP) is widely reported to specifically activate transient receptor potential vanilloid 1 (TRPV1) channel, trigger an increase in intracellular Ca2+ concentration, which is closely linked with ferroptosis, and participate in decreased oxygen consumption by inhibiting HIF-1α in tumor cells, potentiating PDT antitumor efficiency. Thus, CAP and the photosensitizer IR780 are coencapsulated into highly biocompatible human serum albumin (HSA) to construct a nanoplatform (CI@HSA NPs) for synergistic tumor treatment under near-infrared (NIR) irradiation. Furthermore, the potential underlying signaling pathways of the combination therapy are investigated. CI@HSA NPs achieve real-time dynamic distribution monitoring and exhibit excellent antitumor efficacy with superior biosafety in vivo. Overall, this work highlights a promising NIR imaging-guided "pro-death" strategy to overcome the limitations of PDT for OS by promoting ferroptosis and alleviating hypoxia, providing inspiration and support for future innovative tumor therapy approaches.

The efficacy of ferroptosis-inducing compounds IKE and RSL3 correlates with the expression of ferroptotic pathway regulators CD71 and SLC7A11 in biliary tract cancer cells

INTRODUCTION

Biliary tract cancer (BTC) is a lethal disease with a bad overall survivability, partly arising from inadequate therapeutic alternatives, detection at a belated stage, and a resistance to common therapeutic approaches. Ferroptosis is a form of programmed cell death that depends on reactive oxygen species (ROS) and iron, causing excessive peroxidation of polyunsaturated fatty acids (PUFAs). Therefore, the objective of this investigation is, whether ferroptosis can be induced in BTC in vitro and whether this induction is dependent on specific molecular markers.

METHODS

The study conducted resazurin assay and IC25/50 calculation to explore the possible cytotoxic outcomes of different classes of ferroptosis-inducing substances (FINs) on a comprehensive in vitro model of 11 BTC cell lines. Combinatory treatments with different cell death inhibitors were performed to evaluate the magnitude of ferroptosis induction. To ascertain whether ferroptotic cell death occurred, liperfluo and iron assay kits were employed to evaluate lipid ROS and intracellular iron abundance. Potential biomarkers of ferroptosis sensitivity were then assessed via western blot analysis, a rtPCR panel and functional assay kits.

RESULTS

The study found that different FINs reduced cell viability in a cell line-dependent manner. In addition, we measured increased lipid ROS and intracellular Fe2+ levels upon exposure to FINs in BTC cells. Combining FINs with inhibitors of ferroptosis, necroptosis or apoptosis suggests the occurrence of ferroptotic events in BTC cell lines CCC-5, HuH-28 and KKU-055. Furthermore, we found that BTC cells display a heterogeneous profile regarding different molecular genes/markers of ferroptosis. Subsequent analysis revealed that sensitivity of BTC cells towards IKE and RSL3 positively correlated with CD71 and SLC7A11 protein expression.

CONCLUSION

Our results demonstrate that induction of ferroptosis is a promising approach to inhibit BTC cell growth and that the sensitivity of BTC cells towards ferroptosis induction might be dependent on molecular markers such as CD71 and SLC7A11.

Single-cell characterization of infiltrating T cells identifies novel targets for gallbladder cancer immunotherapy

Gallbladder cancer (GBC) is among the most common malignancies of biliary tract system due to its limited treatments. The immunotherapeutic targets for T cells are appealing, however, heterogeneity of T cells hinds its further development. We systematically construct T cell atlas by single-cell RNA sequencing; and utilized the identified gene signatures of high_CNV_T cells to predict molecular subtyping towards personalized therapeutic treatments for GBC. We identified 12 T cell subtypes, where exhausted CD8+ T cells, activated/exhausted CD8+ T cells, and regulatory T cells were predominant in tumors. There appeared to be an inverse relationship between Th17 and Treg populations with Th17 levels significantly reduced, whereas Tregs were concomitantly increased. Furthermore, we first established subtyping criterion to identify three subtypes of GBC based on their pro-tumorigenic microenvironments, e.g., the type 1 group shows more M2 macrophages infiltration, while the type 2 group is infiltrated by highly exhausted CD8+ T cells, B cells and Tregs with suppressive activities. Our study provides valuable insights into T cell heterogeneity and suggests that molecular subtyping based on T cells might provide a potential immunotherapeutic strategy to improve GBC treatment.

Nicotinamide mononucleotide induces autophagy and ferroptosis via AMPK/mTOR pathway in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common malignancy worldwide. Herein, we investigated the role of nicotinamide mononucleotide (NMN) in HCC progression. HCC cells were treated with NMN (125, 250, and 500 μM), and then nicotinamide adenine dinucleotide (NAD+ ) and NADH levels in HCC cells were measured to calculate NAD+ /NADH ratio. Cell proliferation, apoptosis, autophagy and ferroptosis were determined. AMPK was knocked down to confirm the involvement of AMPK/mTOR signaling. Furthermore, tumor-inhibitory effect of NMN was investigated in xenograft models. Exposure to NMN dose-dependently increased NAD+ level and NAD+ /NADH ratio in HCC cells. After NMN treatment, cell proliferation was inhibited, whereas apoptosis was enhanced in both cell lines. Additionally, NMN dose-dependently enhanced autophagy/ferroptosis and activated AMPK/mTOR pathway in HCC cells. AMPK knockdown partially rescued the effects of NMN in vitro. Furthermore, NMN treatment restrained tumor growth in nude mice, activated autophagy/ferroptosis, and promoted apoptosis and necrosis in tumor tissues. The results indicate that NMN inhibits HCC progression by inducing autophagy and ferroptosis via AMPK/mTOR signaling. NMN may serve as a promising agent for HCC treatment.

Regulation of ferroptosis by PI3K/Akt signaling pathway: a promising therapeutic axis in cancer

The global challenge posed by cancer, marked by rising incidence and mortality rates, underscores the urgency for innovative therapeutic approaches. The PI3K/Akt signaling pathway, frequently amplified in various cancers, is central in regulating essential cellular processes. Its dysregulation, often stemming from genetic mutations, significantly contributes to cancer initiation, progression, and resistance to therapy. Concurrently, ferroptosis, a recently discovered form of regulated cell death characterized by iron-dependent processes and lipid reactive oxygen species buildup, holds implications for diseases, including cancer. Exploring the interplay between the dysregulated PI3K/Akt pathway and ferroptosis unveils potential insights into the molecular mechanisms driving or inhibiting ferroptotic processes in cancer cells. Evidence suggests that inhibiting the PI3K/Akt pathway may sensitize cancer cells to ferroptosis induction, offering a promising strategy to overcome drug resistance. This review aims to provide a comprehensive exploration of this interplay, shedding light on the potential for disrupting the PI3K/Akt pathway to enhance ferroptosis as an alternative route for inducing cell death and improving cancer treatment outcomes.

Pb(NO3 )2 induces cell apoptosis through triggering of reactive oxygen species accumulation and disruption of mitochondrial function via SIRT3/SOD2 pathways

Lead (Pb) is nonbiodegradable and toxic to the lungs. To investigate the potential mechanisms of Pb-induced reactive oxygen species (ROS) accumulation and cell death in the lungs, human non-small lung carcinoma H460 cells were stimulated with Pb(NO3 )2 in this study. The results showed that Pb(NO3 )2 stimulation increased cell death by inducing cell apoptosis which showed a reduced Bcl-2 expression and an enhanced caspase 3 activation. Pb(NO3 )2 also caused the production of H2 O2 in H460 cells that triggering the buildup of ROS and mitochondrial membrane potential loss. We found that Pb(NO3 )2 modulates oxidoreductive activity through reduced the glutathione-disulfide reductase and glutathione levels in Pb(NO3 )2 -exposed H460 cells. Furthermore, the superoxide dismutase (SOD) upstream molecule sirtuin 3 (SIRT3) was increased with Pb(NO3 )2 dose. Collectively, these results demonstrate that Pb(NO3 )2 promotes lung cell death through SIRT3/SOD-mediated ROS accumulation and mitochondrial dysfunction.

Hesperetin promotes diabetic wound healing by inhibiting ferroptosis through the activation of SIRT3

Hesperetin (HST) is a flavonoid compound naturally occurring in citrus fruits and is widespread in various traditional medicinal herbs such as grapefruit peel, orange peel, and tangerine peel. These plant materials are commonly used in traditional Chinese medicine to prepare herbal remedies. The study aimed to investigate the potential molecular mechanisms through which HST reduces ferroptosis in human umbilical vein endothelial cells (HUVECs) and promotes angiogenesis and wound healing. We employed network pharmacology to predict the downstream targets affected by HST. The expression of markers related to ferroptosis was assessed through Western blot (WB) and polymerase chain reaction. Intracellular levels of ferroptosis-related metabolism were examined using glutathione/oxidized glutathione (GSH/GSSG) and malondialdehyde (MDA) assay kits. Mitochondrial status and iron levels within the cells were investigated through staining with Mitosox, FerroOrange, and JC1 staining. Potential downstream direct targets of HST were identified using molecular docking. Additionally, wound healing and neovascularization within the wound site were analyzed using various methods including HE staining, Masson's staining, immunohistochemistry, and Doppler hemodynamics assessment. HST effectively inhibits the elevated levels of intracellular ferroptosis stimulated by ERASTIN. Furthermore, we observed that HST achieves this inhibition of ferroptosis by activating SIRT3. In a diabetic rat wound model, HST significantly promotes wound healing, reducing levels of tissue ferroptosis, consistent with our in vitro findings. This study demonstrates that HST can inhibit the progression of ferroptosis and protect the physiological function of HUVECs by activating SIRT3. HST holds promise as a natural compound for promoting diabetic wound healing.

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.

Targeting SIRT3 sensitizes glioblastoma to ferroptosis by promoting mitophagy and inhibiting SLC7A11

Glioblastoma (GBM) cells require large amounts of iron for tumor growth and progression, which makes these cells vulnerable to destruction via ferroptosis induction. Mitochondria are critical for iron metabolism and ferroptosis. Sirtuin-3 (SIRT3) is a deacetylase found in mitochondria that regulates mitochondrial quality and function. This study aimed to characterize SIRT3 expression and activity in GBM and investigate the potential therapeutic effects of targeting SIRT3 while also inducing ferroptosis in these cells. We first found that SIRT3 expression was higher in GBM tissues than in normal brain tissues and that SIRT3 protein expression was upregulated during RAS-selective lethal 3 (RSL3)-induced GBM cell ferroptosis. We then observed that inhibition of SIRT3 expression and activity in GBM cells sensitized GBM cells to RSL3-induced ferroptosis both in vitro and in vivo. Mechanistically, SIRT3 inhibition led to ferrous iron and ROS accumulation in the mitochondria, which triggered mitophagy. RNA-Sequencing analysis revealed that upon SIRT3 knockdown in GBM cells, the mitophagy pathway was upregulated and SLC7A11, a critical antagonist of ferroptosis via cellular import of cystine for glutathione (GSH) synthesis, was downregulated. Forced expression of SLC7A11 in GBM cells with SIRT3 knockdown restored cellular cystine uptake and consequently the cellular GSH level, thereby partially rescuing cell viability upon RSL3 treatment. Furthermore, in GBM cells, SIRT3 regulated SLC7A11 transcription through ATF4. Overall, our study results elucidated novel mechanisms underlying the ability of SIRT3 to protect GBM from ferroptosis and provided insight into a potential combinatorial approach of targeting SIRT3 and inducing ferroptosis for GBM treatment.

SIRT3 Activation a Promise in Drug Development? New Insights into SIRT3 Biology and Its Implications on the Drug Discovery Process

Sirtuins catalyze deacetylation of lysine residues with a NAD+-dependent mechanism. In mammals, the sirtuin family is composed of seven members, divided into four subclasses that differ in substrate specificity, subcellular localization, regulation, as well as interactions with other proteins, both within and outside the epigenetic field. Recently, much interest has been growing in SIRT3, which is mainly involved in regulating mitochondrial metabolism. Moreover, SIRT3 seems to be protective in diseases such as age-related, neurodegenerative, liver, kidney, heart, and metabolic ones, as well as in cancer. In most cases, activating SIRT3 could be a promising strategy to tackle these health problems. Here, we summarize the main biological functions, substrates, and interactors of SIRT3, as well as several molecules reported in the literature that are able to modulate SIRT3 activity. Among the activators, some derive from natural products, others from library screening, and others from the classical medicinal chemistry approach.

Context-dependent role of SIRT3 in cancer

Sirtuin 3 (SIRT3), an NAD+-dependent deacetylase, plays a key role in the modulation of metabolic reprogramming and regulation of cell death, as well as in shaping tumor phenotypes. Owing to its critical role in determining tumor-type specificity or the direction of tumor evolution, the development of small-molecule modulators of SIRT3, including inhibitors and activators, is of significant interest. In this review, we discuss recent studies on the oncogenic or tumor-suppressive functions of SIRT3, evaluate advances in SIRT3-targeted drug discovery, and present potential avenues for the design of small-molecule modulators of SIRT3 for cancer therapy.

A review on SIRT3 and its natural small molecule activators as a potential Preventive and therapeutic target

Sirtuins (SIRTs) were originally characterized by yeast Sir2 as a lifespan regulator that is conserved in all three structural domains of bacteria, archaea and eukaryotes and belong to histone deacetylases consisting of seven members (SIRT1-SIRT7). Surprisingly, SIRTs have been shown to play important regulatory roles in almost all cellular functions, including mitochondrial biogenesis, oxidative stress, inflammation, cell growth, energy metabolism, neural function, and stress resistance. Among the SIRT members, sirtuin 3 (SIRT3) is one of the most important deacetylases that regulates the mitochondrial acetylation and plays a role in pathological processes, such as metabolism, DNA repair, oxidative stress, apoptosis and ferroptosis. Therefore, SIRT3 is considered as a potential target for the treatment of a variety of pathological diseases, including metabolic diseases, neurodegenerative diseases, age-related diseases and others. Furthermore, the isolation, screening, and development of SIRT3 signaling agonists, especially from natural products, have become a widely investigated objective. This paper describes the structure of SIRT3 protein, discusses the pathological process of SIRT3-mediated acetylation modification, and reviews the role of SIRT3 in diseases, SIRT3 activators and its related disease studies.

Eriocitrin inhibits epithelial-mesenchymal transformation (EMT) in lung adenocarcinoma cells via triggering ferroptosis

INTRODUCTION

Lung adenocarcinoma (LUAD) is the most prevalent pathological subtype of non-small cell lung cancer (NSCLC), characterized by a high propensity for relapse and metastasis due to epithelial-mesenchymal transition (EMT) of cancer cells. Ferroptosis, a newly discovered regulated cell death modality, is interconnected with the EMT process in certain cancers. Eriocitrin, a natural flavonoid compound, exerts anti-inflammatory and anticancer effects.

OBJECTIVES

The aim of this study is to investigate the potential inhibitory effect of eriocitrin on lung adenocarcinoma metastasis and explore whether its underlying mechanism involves ferroptosis induction in cancer cells.

METHODS

The CCK8 assay and wound healing assay and transwell were conducted to determine the cell viability and migration ability of A549 and H1299 cells, respectively. EMT process was assessed by western blot and RT-PCR to detect protein and mRNA levels of EMT markers. ROS and cell iron were measured to determine ferroptosis level.

RESULTS

Eriocitrin treatment significantly inhibited cell viability and migration ability in a concentration-dependent manner. Furthermore, eriocitrin administration for 24 hours resulted in enhanced expression of E-cadherin, while downregulating vimentin, N-cadherin and snail expression, indicating marked repression of the EMT process. Additionally, eriocitrin significantly induced ferroptosis in A549 and H1299 cells, as evidenced by increased ROS levels, downregulation of Nrf-2, SLC7A11 and GPX4 expression, and enhanced cellular iron accumulation. Moreover, pretreatment with the ferroptosis inhibitor ferrostatin-1 effectively abrogated the inhibitory effects of eriocitrin on EMT.

CONCLUSIONS

Our findings further support the anti-cancer properties of eriocitrin, as evidenced by its ability to inhibit the EMT process in LUAD cells, which is partially mediated through induction of ferroptosis in cancer cells.

Isoliquiritigenin induces HMOX1 and GPX4-mediated ferroptosis in gallbladder cancer cells

BACKGROUND

Gallbladder cancer (GBC) is the most common malignant tumor of biliary tract. Isoliquiritigenin (ISL) is a natural compound with chalcone structure extracted from the roots of licorice and other plants. Relevant studies have shown that ISL has a strong anti-tumor ability in various types of tumors. However, the research of ISL against GBC has not been reported, which needs to be further investigated.

METHODS

The effects of ISL against GBC cells in vitro and in vivo were characterized by cytotoxicity test, RNA-sequencing, quantitative real-time polymerase chain reaction, reactive oxygen species (ROS) detection, lipid peroxidation detection, ferrous ion detection, glutathione disulphide/glutathione (GSSG/GSH) detection, lentivirus transfection, nude mice tumorigenesis experiment and immunohistochemistry.

RESULTS

ISL significantly inhibited the proliferation of GBC cells in vitro . The results of transcriptome sequencing and bioinformatics analysis showed that ferroptosis was the main pathway of ISL inhibiting the proliferation of GBC, and HMOX1 and GPX4 were the key molecules of ISL-induced ferroptosis. Knockdown of HMOX1 or overexpression of GPX4 can reduce the sensitivity of GBC cells to ISL-induced ferroptosis and significantly restore the viability of GBC cells. Moreover, ISL significantly reversed the iron content, ROS level, lipid peroxidation level and GSSG/GSH ratio of GBC cells. Finally, ISL significantly inhibited the growth of GBC in vivo and regulated the ferroptosis of GBC by mediating HMOX1 and GPX4 .

CONCLUSION

ISL induced ferroptosis in GBC mainly by activating p62-Keap1-Nrf2-HMOX1 signaling pathway and down-regulating GPX4 in vitro and in vivo . This evidence may provide a new direction for the treatment of GBC.

Acetylation, ferroptosis, and their potential relationships: Implications in myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury (MIRI) is a serious complication affecting the prognosis of patients with myocardial infarction and can cause cardiac arrest, reperfusion arrhythmias, no-reflow, and irreversible myocardial cell death. Ferroptosis, an iron-dependent, peroxide-driven, non-apoptotic form of regulated cell death, plays a vital role in reperfusion injury. Acetylation, an important post-translational modification, participates in many cellular signaling pathways and diseases, and plays a pivotal role in ferroptosis. Elucidating the role of acetylation in ferroptosis may therefore provide new insights for the treatment of MIRI. Here, we summarized the recently discovered knowledge about acetylation and ferroptosis in MIRI. Finally, we focused on the acetylation modification during ferroptosis and its potential relationship with MIRI.

Multiple forms of cell death: A focus on the PI3K/AKT pathway

Cell death is a natural biological process that occurs in living organisms. Since 1963, extensive research has shed light on the occurrence, progress, and final outcome of cell death. According to different cell phenotypes, it is classified into different types, including apoptosis, pyroptosis, necroptosis, autophagy, ferroptosis, cuproptosis, and so on. However, regardless of the form of cell death, what we ultimately expect is the disappearance of abnormal cells, such as tumor cells, while normal cells survive. As a result, it is vital to investigate the details of cell death, including death triggers, potent regulators, and executioners. Although significant progress has been made in understanding molecular pathways of cell death, many aspects remain unclear because of the complex regulatory networks in cells. Among them, the phosphoinositide-3-kinase (PI3K)/protein kinase B(AKT) pathway is discovered to be a crucial regulator of the cell death process. AKT, as a proto-oncogene, has become a major focus of attention in the medical community due to its role in regulating a multiplicity of cellular functions counting metabolism, immunity, proliferation, survival, transcription, and protein synthesis. Here, we explored the connection between the PI3K/AKT pathway and cell death, aiming to enhance our comprehension of the mechanism underlying this process. Such knowledge may pave the way for the subsequent development of more effective disease treatments, such as finding suitable targets for drug intervention.

SIRT3-mediated autophagy contributes to ferroptosis-induced anticancer by inducing the formation of BECN1-SLC7A11 complex

Ferroptosis is an autophagy-dependent cell death associated with iron accumulation and lipid peroxidation, which plays a crucial part in anticancer activity. Sirtuin 3 (SIRT3) positively regulates autophagy by phosphorylation of activated protein kinase (AMPK). However, whether SIRT3-mediated autophagy can inhibit the cystine/glutamate antiporter (system Xc-) activity by inducing the formation of a BECN1-SLC7A11 complex and consequently promote induction of ferroptosis is unknown. Using both in vitro and in vivo models, we revealed that combination treatment with erastin and TGF-β1 decreased the expression of epithelial-mesenchymal transition-related markers and inhibited the invasion and metastasis of breast cancer. Furthermore, TGF-β1 promoted erastin-induced ferroptosis-related indicators in MCF-7 cells and tumor-bearing nude mice models. Interestingly, the expression of SIRT3, p-AMPK, and autophagy-related markers were significantly elevated after co-treatment with erastin and TGF-β1, suggesting that combination treatment of erastin and TGF-β1 mediated autophagy by the SIRT3/AMPK signaling pathway. In addition, erastin-induced BECN1-SLC7A11 complexes were more abundant after co-treatment with TGF-β1. This effect was inhibited by the autophagy inhibitor 3-methyladenine or siSIRT3, further revealing that combination treatment of erastin and TGF-β1 mediated autophagy-dependent ferroptosis by inducing the formation of BECN1-SLC7A11 complexes. Our results agreed with the concept that BECN1 directly binds to SLC7A11 to inhibit system Xc- activity. In summary, our studies confirmed that SIRT3-mediated autophagy is conducive to ferroptosis-mediated anticancer activity by inducing the formation of BECN1-SLC7A11 complexes, which is a potential therapeutic approach for treating breast cancer.

The ACSL4 Network Regulates Cell Death and Autophagy in Diseases

Lipid metabolism, cell death, and autophagy are interconnected processes in cells. Dysregulation of lipid metabolism can lead to cell death, such as via ferroptosis and apoptosis, while lipids also play a crucial role in the regulation of autophagosome formation. An increased autophagic response not only promotes cell survival but also causes cell death depending on the context, especially when selectively degrading antioxidant proteins or organelles that promote ferroptosis. ACSL4 is an enzyme that catalyzes the formation of long-chain acyl-CoA molecules, which are important intermediates in the biosynthesis of various types of lipids. ACSL4 is found in many tissues and is particularly abundant in the brain, liver, and adipose tissue. Dysregulation of ACSL4 is linked to a variety of diseases, including cancer, neurodegenerative disorders, cardiovascular disease, acute kidney injury, and metabolic disorders (such as obesity and non-alcoholic fatty liver disease). In this review, we introduce the structure, function, and regulation of ACSL4; discuss its role in apoptosis, ferroptosis, and autophagy; summarize its pathological function; and explore the potential implications of targeting ACSL4 in the treatment of various diseases.

The epigenetic regulatory mechanisms of ferroptosis and its implications for biological processes and diseases

Ferroptosis is a form of regulated cell death triggered by the iron-dependent peroxidation of phospholipids. Interactions of iron and lipid metabolism factors jointly promote ferroptosis. Ferroptosis has been demonstrated to be involved in the development of various diseases, such as tumors and degenerative diseases (e.g., aortic dissection), and targeting ferroptosis is expected to be an effective strategy for the treatment of these diseases. Recent studies have shown that the regulation of ferroptosis is affected by multiple mechanisms, including genetics, epigenetics, posttranscriptional modifications, and protein posttranslational modifications. Epigenetic changes have garnered considerable attention due to their importance in regulating biological processes and potential druggability. There have been many studies on the epigenetic regulation of ferroptosis, including histone modifications (e.g., histone acetylation and methylation), DNA methylation, and noncoding RNAs (e.g., miRNAs, circRNAs, and lncRNAs). In this review, we summarize recent advances in research on the epigenetic mechanisms involved in ferroptosis, with a description of RNA N6-methyladenosine (m6A) methylation included, and the importance of epigenetic regulation in biological processes and ferroptosis-related diseases, which provides reference for the clinical application of epigenetic regulators in the treatment of related diseases by targeting ferroptosis.

Cholesterol confers ferroptosis resistance onto myeloid-biased hematopoietic stem cells and prevents irradiation-induced myelosuppression

There is growing appreciation that hematopoietic alterations underpin the ubiquitous detrimental effects of metabolic disorders. The susceptibility of bone marrow (BM) hematopoiesis to perturbations of cholesterol metabolism is well documented, while the underlying cellular and molecular mechanisms remain poorly understood. Here we reveal a distinct and heterogeneous cholesterol metabolic signature within BM hematopoietic stem cells (HSCs). We further show that cholesterol directly regulates maintenance and lineage differentiation of long-term HSCs (LT-HSCs), with high levels of intracellular cholesterol favoring maintenance and myeloid bias of LT-HSCs. During irradiation-induced myelosuppression, cholesterol also safeguards LT-HSC maintenance and myeloid regeneration. Mechanistically, we unravel that cholesterol directly and distinctively enhances ferroptosis resistance and boosts myeloid but dampens lymphoid lineage differentiation of LT-HSCs. Molecularly, we identify that SLC38A9-mTOR axis mediates cholesterol sensing and signal transduction to instruct lineage differentiation of LT-HSCs as well as to dictate ferroptosis sensitivity of LT-HSCs through orchestrating SLC7A11/GPX4 expression and ferritinophagy. Consequently, myeloid-biased HSCs are endowed with a survival advantage under both hypercholesterolemia and irradiation conditions. Importantly, a mTOR inhibitor rapamycin and a ferroptosis inducer imidazole ketone erastin prevent excess cholesterol-induced HSC expansion and myeloid bias. These findings unveil an unrecognized fundamental role of cholesterol metabolism in HSC survival and fate decisions with valuable clinical implications.

SIRT3 Deficiency Enhances Ferroptosis and Promotes Cardiac Fibrosis via p53 Acetylation

Cardiac fibrosis plays an essential role in the development of diastolic dysfunction and contributes to heart failure with preserved ejection fraction (HFpEF). Our previous studies suggested Sirtuin 3 (SIRT3) as a potential target for cardiac fibrosis and heart failure. In the present study, we explored the role of SIRT3 in cardiac ferroptosis and its contribution to cardiac fibrosis. Our data showed that knockout of SIRT3 resulted in a significant increase in ferroptosis, with increased levels of 4-hydroxynonenal (4-HNE) and downregulation of glutathione peroxidase 4 (GPX-4) in the mouse hearts. Overexpression of SIRT3 significantly blunted ferroptosis in response to erastin, a known ferroptosis inducer, in H9c2 myofibroblasts. Knockout of SIRT3 resulted in a significant increase in p53 acetylation. Inhibition of p53 acetylation by C646 significantly alleviated ferroptosis in H9c2 myofibroblasts. To further explore the involvement of p53 acetylation in SIRT3-mediated ferroptosis, we crossed acetylated p53 mutant (p534KR) mice, which cannot activate ferroptosis, with SIRT3KO mice. SIRT3KO/p534KR mice exhibited a significant reduction in ferroptosis and less cardiac fibrosis compared to SIRT3KO mice. Furthermore, cardiomyocyte-specific knockout of SIRT3 (SIRT3-cKO) in mice resulted in a significant increase in ferroptosis and cardiac fibrosis. Treatment of SIRT3-cKO mice with the ferroptosis inhibitor ferrostatin-1 (Fer-1) led to a significant reduction in ferroptosis and cardiac fibrosis. We concluded that SIRT3-mediated cardiac fibrosis was partly through a mechanism involving p53 acetylation-induced ferroptosis in myofibroblasts.

DNA methylation of RUNX3 promotes the progression of gallbladder cancer through repressing SLC7A11-mediated ferroptosis

Gallbladder cancer (GBC) is a type of rare but highly aggressive cancer with a dismal prognosis. Runt-related transcription factor 3 (RUNX3), a member of the runt-domain family, and its promoter methylation have been widely observed in a variety of human malignancies. However, the biological function and underlying mechanism of RUNX3 in GBC remain elusive. In this study, bisulfate sequencing PCR (BSP), Western blot, and qPCR were applied to identify the expression level and DNA methylation level of RUNX3 in GBC tissues and cells. The transcriptional relationship between RUNX3 and Inhibitor of growth 1 (ING1) was validated by dual-luciferase reporter assay and ChIP assay. A series of gain-of-function and loss-of-function assays were performed to detect the function and the regulatory relationship of RUNX3 in vitro and in vivo. RUNX3 was aberrantly downregulated in GBC cells and tissues caused by DNA Methyltransferase 1 (DNMT1)-mediated methylation, and downregulation of RUNX3 is associated with poor prognosis of GBC patients. Functional experiments reveal that RUNX3 can induce ferroptosis of GBC cells in vitro and in vivo. Mechanistically, RUNX3 induces ferroptosis by activating ING1 transcription, thereby repressing SLC7A11 in a p53-dependent manner. In conclusion, the downregulation of RUNX3 is mediated by DNA methylation, which promotes the pathogenesis of gallbladder cancer through attenuating SLC7A11-mediated ferroptosis. This study gives novel insights into the role of RUNX3 in the ferroptosis of GBC cells, which may contribute to developing potential treatment targets for GBC.

Sirtuin-3-Mediated Cellular Metabolism Links Cardiovascular Remodeling with Hypertension

Hypertension can cause structural and functional abnormalities in the cardiovascular system, which can be attributed to both hemodynamic and nonhemodynamic factors. These alterations are linked with metabolic changes and are induced by pathological stressors. Sirtuins are enzymes that act as stress sensors and regulate metabolic adaptation by deacetylating proteins. Among them, mitochondrial SIRT3 performs a crucial role in maintaining metabolic homeostasis. Evidence from experimental and clinical studies has shown that hypertension-induced decreases in SIRT3 activity can lead to cellular metabolism reprogramming and, subsequently, increased susceptibility to endothelial dysfunction, myocardial hypertrophy, myocardial fibrosis, and heart failure. This review presents recent research advances in SIRT3-mediated metabolic adaptation in hypertensive cardiovascular remodeling.

The Role of NAD+, SIRTs Interactions in Stimulating and Counteracting Carcinogenesis

The World Health Organization has identified oncological diseases as one of the most serious health concerns of the current century. Current research on oncogenesis is focused on the molecular mechanisms of energy-biochemical reprogramming in cancer cell metabolism, including processes contributing to the Warburg effect and the pro-oncogenic and anti-oncogenic roles of sirtuins (SIRTs) and poly-(ADP-ribose) polymerases (PARPs). However, a clear understanding of the interaction between NAD⁺, SIRTs in cancer development, as well as their effects on carcinogenesis, has not been established, and literature data vary greatly. This work aims to provide a summary and structure of the available information on NAD⁺, SIRTs interactions in both stimulating and countering carcinogenesis, and to discuss potential approaches for pharmacological modulation of these interactions to achieve an anticancer effect.

The deubiquitinase USP11 ameliorates intervertebral disc degeneration by regulating oxidative stress-induced ferroptosis via deubiquitinating and stabilizing Sirt3

Increasing studies have reported that intervertebral disc degeneration (IVDD) is the main contributor and independent risk factor for low back pain (LBP), it would be, therefore, enlightening that investigating the exact pathogenesis of IVDD and developing target-specific molecular drugs in the future. Ferroptosis is a new form of programmed cell death characterized by glutathione (GSH) depletion, and inactivation of the regulatory core of the antioxidant system (glutathione system) GPX4. The close relationship of oxidative stress and ferroptosis has been studied in various of diseases, but the crosstalk between of oxidative stress and ferroptosis has not been explored in IVDD. At the beginning of the current study, we proved that Sirt3 decreases and ferroptosis occurs after IVDD. Next, we found that knockout of Sirt3 (Sirt3^-/-) promoted IVDD and poor pain-related behavioral scores via increasing oxidative stress-induced ferroptosis. The (immunoprecipitation coupled with mass spectrometry) IP/MS and co-IP demonstrated that USP11 was identified to stabilize Sirt3 via directly binding to Sirt3 and deubiquitinating Sirt3. Overexpression of USP11 significantly ameliorate oxidative stress-induced ferroptosis, thus relieving IVDD by increasing Sirt3. Moreover, knockout of USP11 in vivo (USP11^-/-) resulted in exacerbated IVDD and poor pain-related behavioral scores, which could be reversed by overexpression of Sirt3 in intervertebral disc. In conclusion, the current study emphasized the importance of the interaction of USP11 and Sirt3 in the pathological process of IVDD via regulating oxidative stress-induced ferroptosis, and USP11-mediated oxidative stress-induced ferroptosis is identified as a promising target for treating IVDD.

Epithelial-Mesenchymal Plasticity: Implications for Ferroptosis Vulnerability and Cancer Therapy

Cancers polarized to a mesenchymal or poorly differentiated state can often evade cell death induced by conventional therapies. The epithelial-mesenchymal transition is involved in lipid metabolism and increases polyunsaturated fatty acid levels in cancer cells, contributing to chemo- and radio-resistance. Altered metabolism in cancer enables invasion and metastasis but is prone to lipid peroxidation under oxidative stress. Cancers with mesenchymal rather than epithelial signatures are highly vulnerable to ferroptosis. Therapy-resistant persister cancer cells show a high mesenchymal cell state and dependence on the lipid peroxidase pathway, which can respond more sensitively to ferroptosis inducers. Cancer cells may survive under specific metabolic and oxidative stress conditions, and targeting this unique defense system can selectively kill only cancer cells. Therefore, this article summarizes the core regulatory mechanisms of ferroptosis in cancer, the relationship between ferroptosis and epithelial-mesenchymal plasticity, and the implications of epithelial-mesenchymal transition for ferroptosis-based cancer therapy.

CDGSH iron sulfur domain 2 over-expression alleviates neuronal ferroptosis and brain injury by inhibiting lipid peroxidation via AKT/mTOR pathway following intracerebral hemorrhage in mice

Ferroptosis has been implicated in the pathogenesis of secondary brain injury following intracerebral hemorrhage (ICH), and regulating this process is considered a potential therapy for alleviating further brain injury. A previous study showed that CDGSH iron sulfur domain 2 (CISD2) can inhibit ferroptosis in cancer. Thus, we investigated the effects of CISD2 on ferroptosis and the mechanisms underlying its neuroprotective role in mice after ICH. CISD2 expression markedly increased after ICH. CISD2 over-expression significantly decreased the number of Fluoro-Jade C-positive neurons and alleviated brain edema and neurobehavioral deficits at 24 h after ICH. In addition, CISD2 over-expression up-regulated the expression of p-AKT, p-mTOR, ferritin heavy chain 1, glutathione peroxidase 4, ferroportin, glutathione, and glutathione peroxidase activity, which are markers of ferroptosis. Additionally, CISD2 over-expression down-regulated the levels of malonaldehyde, iron content, acyl-CoA synthetase long-chain family member 4, transferrin receptor 1, and cyclooxygenase-2 at 24 h after ICH. It also alleviated mitochondrial shrinkage and decreased the density of the mitochondrial membrane. Furthermore, CISD2 over-expression increased the number of GPX4-positive neurons following ICH induction. Conversely, knockdown of CISD2 aggravated neurobehavioral deficits, brain edema, and neuronal ferroptosis. Mechanistically, MK2206, an AKT inhibitor, suppressed p-AKT and p-mTOR and reversed the effects of CISD2 over-expression on markers of neuronal ferroptosis and acute neurological outcome. Taken together, CISD2 over-expression alleviated neuronal ferroptosis and improved neurological performance, which may be mediated through the AKT/mTOR pathway after ICH. Thus, CISD2 may be a potential target to mitigate brain injury via the anti-ferroptosis effect after ICH.

Abietic acid induces ferroptosis via the activation of the HO-1 pathway in bladder cancer cells

BACKGROUND

Bladder cancer (BC) is a common urological malignancy that still lacks effective treatments. Abietic acid (AA) is an abietane diterpene that possesses various biological activities, including antitumor activity. This study aimed at evaluating the effects of AA on BC cells.

MATERIALS AND METHODS

The 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) assay was used to assess the effects of AA on the viability of BC cells. Annexin-V and FITC staining was used to assess cellular death. The type of cell death was determined by the administration of various specific cell death inhibitors. Commercial kits were used to measure the levels of reactive oxygen species (ROS), intracellular iron, malondialdehyde (MDA), and glutathione (GSH). Real-time polymerase chain reaction (RT-PCR) and western blot analysis were used to assay mRNA and protein levels, respectively. The role of glutathione peroxidase 4 (GPX4) in the antitumor effects of AA was evaluated using the forced expression of GPX4 in BC cells. The impact of HO-1 on the antitumor effects of AA was examined by gene silencing and pharmacological inhibition of the protein. Finally, the antitumor effects of AA were evaluated in xenograft models.

RESULTS

AA selectively inhibited the viability of BC cells but not normal cells. AA-induced ferroptosis in BC cells was evidenced by the upregulation of ROS, intracellular iron, and MDA. AA treatment led to the downregulation of GPX4 and the upregulation of HO-1 in BC cells. Forced expression of GPX4 or inhibition of HO-1 resulted in decreased ferroptosis triggered by AA in BC cells. AA also showed synergistic effects with various chemotherapeutic agents against BC and inhibited the growth of BC cells in vivo.

CONCLUSION

This study revealed AA-induced ferroptosis in BC cells both in vitro and in vivo. AA might be applied as a promising agent for the treatment of BC.

Elucidating the progress and impact of ferroptosis in hemorrhagic stroke

Hemorrhagic stroke is a devastating cerebrovascular disease with high morbidity and mortality, for which effective therapies are currently unavailable. Based on different bleeding sites, hemorrhagic stroke can be generally divided into intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH), whose pathogenesis share some similarity. Ferroptosis is a recently defined programmed cell deaths (PCDs), which is a critical supplement to the hypothesis on the mechanism of nervous system injury after hemorrhagic stroke. Ferroptosis is characterized by distinctive morphological changes of mitochondria and iron-dependent accumulation of lipid peroxides. Moreover, scientists have successfully demonstrated the involvement of ferroptosis in animal models of ICH and SAH, indicating that ferroptosis is a promising target for hemorrhagic stroke therapy. However, the studies on ferroptosis still faces a serious of technical and theoretical challenges. This review systematically elaborates the role of ferroptosis in the pathogenesis of hemorrhagic stroke and puts forward some opinions on the dilemma of ferroptosis research.

p53 Activates the Lipoxygenase Activity of ALOX15B via Inhibiting SLC7A11 to Induce Ferroptosis in Bladder Cancer Cells

Bladder cancer is a malignant tumor of the urinary system and is one of the most common cancers worldwide. Lipoxygenases are closely related to the development of various cancers. However, the relationship between lipoxygenases and p53/SLC7A11-dependent ferroptosis in bladder cancer has not been reported. Here, we aimed to investigate the roles and internal mechanisms of lipid peroxidation and p53/SLC7A11-dependent ferroptosis in the development and progression of bladder cancer. First, ultraperformance liquid chromatography-tandem mass spectrometry was performed to measure the metabolite production of lipid oxidation in patients' plasma. The metabolic changes in patients with bladder cancer were discovered, revealing that stevenin, melanin, and octyl butyrate were upregulated. Then, the expressions of lipoxygenase family members were measured to screen out candidates with significant changes in bladder cancer tissues. Among various lipoxygenases, ALOX15B was significantly downregulated in bladder cancer tissues. Moreover, p53 and 4-hydroxynonenal (4-HNE) levels were decreased in bladder cancer tissues. Next, sh-ALOX15B, oe-ALOX15B, or oe-SLC7A11 plasmids were constructed and transfected into bladder cancer cells. Then, the p53 agonist Nutlin-3a, tert-butyl hydroperoxide, iron chelator deferoxamine, and the selective ferroptosis inhibitor ferr1 were added. The effects of ALOX15B and p53/SLC7A11 on bladder cancer cells were evaluated by in vitro and in vivo experiments. We revealed that knockdown of ALOX15B promoted bladder cancer cell growth, which was also found to protect bladder cancer cells from p53-induced ferroptosis. Furthermore, p53 activated ALOX15B lipoxygenase activity by suppressing SLC7A11. Taken together, p53 activated the lipoxygenase activity of ALOX15B via inhibiting SLC7A11 to induce ferroptosis in bladder cancer cells, which provided insight into the molecular mechanism of the occurrence and development of bladder cancer.

The roles of sirtuins in ferroptosis

Ferroptosis represents a novel non-apoptotic form of regulated cell death that is driven by iron-dependent lipid peroxidation and plays vital roles in various diseases including cardiovascular diseases, neurodegenerative disorders and cancers. Plenty of iron metabolism-related proteins, regulators of lipid peroxidation, and oxidative stress-related molecules are engaged in ferroptosis and can regulate this complex biological process. Sirtuins have broad functional significance and are targets of many drugs in the clinic. Recently, a growing number of studies have revealed that sirtuins can participate in the occurrence of ferroptosis by affecting many aspects such as redox balance, iron metabolism, and lipid metabolism. This article reviewed the studies on the roles of sirtuins in ferroptosis and the related molecular mechanisms, highlighting valuable targets for the prevention and treatment of ferroptosis-associated diseases.

Overcoming AZD9291 Resistance and Metastasis of NSCLC via Ferroptosis and Multitarget Interference by Nanocatalytic Sensitizer Plus AHP-DRI-12

The acquired resistance to Osimertinib (AZD9291) greatly limits the clinical benefit of patients with non-small cell lung cancer (NSCLC), whereas AZD9291-resistant NSCLCs are prone to metastasis. It's challenging to overcome AZD9291 resistance and suppress metastasis of NSCLC simultaneously. Here, a nanocatalytic sensitizer (VF/S/A@CaP) is proposed to deliver Vitamin c (Vc)-Fe(II), si-OTUB2, ASO-MALAT1, resulting in efficient inhibition of tumor growth and metastasis of NSCLC by synergizing with AHP-DRI-12, an anti-hematogenous metastasis inhibitor by blocking the amyloid precursor protein (APP)/death receptor 6 (DR6) interaction designed by our lab. Fe²⁺ released from Vc-Fe(II) generates cytotoxic hydroxyl radicals (•OH) through Fenton reaction. Subsequently, glutathione peroxidase 4 (GPX4) is consumed to sensitize AZD9291-resistant NSCLCs with high mesenchymal state to ferroptosis due to the glutathione (GSH) depletion caused by Vc/dehydroascorbic acid (DHA) conversion. By screening NSCLC patients' samples, metastasis-related targets (OTUB2, LncRNA MALAT1) are confirmed. Accordingly, the dual-target knockdown plus AHP-DRI-12 significantly suppresses the metastasis of AZD9291-resistant NSCLC. Such modality leads to 91.39% tumor inhibition rate in patient-derived xenograft (PDX) models. Collectively, this study highlights the vulnerability to ferroptosis of AZD9291-resistant tumors and confirms the potential of this nanocatalytic-medicine-based modality to overcome critical AZD9291 resistance and inhibit metastasis of NSCLC simultaneously.

Emerging role of ferroptosis-related circular RNA in tumor metastasis

Tumor metastasis is an important factor that contributes to the poor prognosis of patients with tumors. Therefore, to solve this problem, research on the mechanism of metastasis is essential. Ferroptosis, a new mode of cell death, is characterized by membrane damage due to lipid peroxidation caused by iron overload. Many studies have shown that excessive ferroptosis can affect tumor metastasis and thus inhibit tumor progression. Recently, circular RNA (circRNA), a type of non-coding RNA, has been shown to be associated with the progression of ferroptosis, thus influencing tumor development. However, the specific mechanisms by which circRNAs affect the progression of ferroptosis and their roles in tumor metastasis are not known. In this review, we systematically discuss the role of circRNAs in regulating tumor ferroptosis and their mechanism of action through sponging miRNAS in various tumors, thereby impacting metastasis. This review helps elucidate the relationship and role of ferroptosis-related circRNAs in tumor metastasis and may provide future researchers with new ideas and directions for targeted therapies.

The sirtuin family in health and disease

Sirtuins (SIRTs) are nicotine adenine dinucleotide(+)-dependent histone deacetylases regulating critical signaling pathways in prokaryotes and eukaryotes, and are involved in numerous biological processes. Currently, seven mammalian homologs of yeast Sir2 named SIRT1 to SIRT7 have been identified. Increasing evidence has suggested the vital roles of seven members of the SIRT family in health and disease conditions. Notably, this protein family plays a variety of important roles in cellular biology such as inflammation, metabolism, oxidative stress, and apoptosis, etc., thus, it is considered a potential therapeutic target for different kinds of pathologies including cancer, cardiovascular disease, respiratory disease, and other conditions. Moreover, identification of SIRT modulators and exploring the functions of these different modulators have prompted increased efforts to discover new small molecules, which can modify SIRT activity. Furthermore, several randomized controlled trials have indicated that different interventions might affect the expression of SIRT protein in human samples, and supplementation of SIRT modulators might have diverse impact on physiological function in different participants. In this review, we introduce the history and structure of the SIRT protein family, discuss the molecular mechanisms and biological functions of seven members of the SIRT protein family, elaborate on the regulatory roles of SIRTs in human disease, summarize SIRT inhibitors and activators, and review related clinical studies.

LCZ696 protects against doxorubicin-induced cardiotoxicity by inhibiting ferroptosis via AKT/SIRT3/SOD2 signaling pathway activation

Doxorubicin (DOX) is an effective and widely used anticancer drug but has limited clinical applicability because of its cardiotoxicity. Ferroptosis plays a key role in DOX-induced cardiac damage and cardiomyocyte cell death. The inhibition of ferroptosis reverses DOX-induced cardiotoxicity (DIC). LCZ696, a first-in-class angiotensin receptor neprilysin inhibitor, protects against DIC. However, the mechanism of action of LCZ696, especially its effect on ferroptosis, is incompletely understood. This study investigates the cardioprotective effects of LCZ696 on DIC in vivo and in vitro.Cardiotoxicity was induced in Wistar rats by tail intravenous injection of 2.5 mg/kg DOX once a week for six weeks. Rats and H9c2 cells were treated with or without LCZ696 to determine the cardioprotective role and underlying mechanisms of LCZ696 against DIC. To assess the role of SIRT3 and correlated pathways in ferroptosis, SIRT3 knockout was performed using lentiviral vectors, and AKT was inhibited with LY294002. LCZ696 significantly attenuated DIC by decreasing the concentrations of lipid reactive oxygen species and malondialdehyde and increasing the levels of glutathione peroxidase-4 and reduced glutathione in cells and heart tissues. Moreover, LCZ696 remodeled myocardial structures and improved heart ventricular function in DOX-treated rats. LCZ696 treatment increased SIRT3 expression and deacetylated its target gene SOD2, and these changes were mediated by AKT activation. SIRT3 knockdown and AKT inhibition induced lipid peroxidation and reduced the protective effect of LCZ696 in H9c2 cells. Collectively,LCZ696 prevents DIC by inhibiting ferroptosis via AKT/SIRT3/SOD2 signaling pathway activation. Thus, LZC696 is a potential therapeutic strategy for DIC.

Transcriptome and proteomics conjoint analysis reveal metastasis inhibitory effect of 6-shogaol as ferroptosis activator through the PI3K/AKT pathway in human endometrial carcinoma in vitro and in vivo

Endometrial cancer remains as one of the widespread female malignancies despite the existing treatment measures mainly surgery, radiotherapy, and chemotherapy. In recent times, studies have focused on medicinal plants such as ginger due to its multifaceted characteristics compared to conventional medicine. 6-Shogaol is regarded as the main active compound of ginger participating in pharmacological activities and combating various health disorders, especially cancer. In our study, we compared the effects of 6-gingerol, 6-paradol, and 6-shogaol on Ishikawa cells, and found 6-shogaol as a more effective ingredient against Ishikawa cell proliferation. Moreover, its promoted ferroptosis, as a result, triggered mitochondrial morphologic alternation, as well as changed iron concentration, GSH and MDA levels. Furthermore, 6-Shogaol inhibited cell metastasis by influencing cell invasion and migration. Finally, 6-shogaol could trigger PI3K/AKT signaling pathways in vitro and in vivo confirmed by western blotting assay and immunohistochemical evaluation. These findings suggest that 6-shogaol can be used as promising functional food component in health diet and in drug target methods for endometrial cancer therapy.

ACSL3 and ACSL4, Distinct Roles in Ferroptosis and Cancers

The long-chain fatty acyl CoA synthetase (ACSLs) family of enzymes contributes significantly to lipid metabolism and produces acyl-coenzyme A by catalyzing fatty acid oxidation. The dysregulation of ACSL3 and ACSL4, which belong to the five isoforms of ACSLs, plays a key role in cancer initiation, development, metastasis, and tumor immunity and may provide several possible therapeutic strategies. Moreover, ACSL3 and ACSL4 are crucial for ferroptosis, a non-apoptotic cell death triggered by the accumulation of membrane lipid peroxides due to iron overload. Here, we present a summary of the current knowledge on ACSL3 and ACSL4 and their functions in various cancers. Research on the molecular mechanisms involved in the regulation of ferroptosis is critical to developing targeted therapies for cancer.

IGF2BP3 promotes progression of gallbladder carcinoma by stabilizing KLK5 mRNA in N6-methyladenosine-dependent binding

Background

Recent studies have reported that IGF2BP3 is linked to the pathogenesis of various malignancies. Since IGF2BP3 is associated with poor outcomes of gallbladder carcinoma (GBC), we aimed to explore the association between its N⁶-methyladenosine (m6A) RNA methylation and GBC progression.

Methods

Bioinformatic analysis of GSE136982, GSE104165, and RNA-seq was performed. In vitro and in vivo gain- and loss-of-function assays were done. qPCR, Western blotting, and IHC were conducted in cells or in collected clinical tissue samples. RNA immunoprecipitation, RNA stability measurement, methylated RNA immunoprecipitation, and dual-luciferase reporter assays were performed in this study.

Results

The expression of IGF2BP3 was higher in GBC tissues than in peritumoral tissues. Functions such as cell proliferation and migration, both in vitro and in vivo, were inhibited by downregulation of IGF2BP3. The analysis of RNA-seq indicated that KLK5 was a downstream target of IGF2BP3. The expression of KLK5 was measured in GBC cells and tumor samples. It was found to be positively correlated with IGF2BP3 level. Upon IGF2BP3 depletion, ectopic expression of KLK5 could rescue cell function in part. Mechanistically, we found that IGF2BP3 directly binds to KLK5 mRNA and regulates its stability in an m6A-dependent manner. As a result, inhibition of KLK5 decreased the expression of PAR2, and deregulated phospho-Akt. Using bioinformatic prediction combined with miRNA microarray analysis, we identified that let-7g-5p is an inhibitor of IGF2BP3, and let-7g-5p expression was negatively correlated with IGF2BP3. Overexpression of let-7g-5p affected the aggressive phenotype of GBC cells by deregulating IGF2BP3, and inhibiting the KLK5/PAR2/AKT axis.

Conclusions

Our data showed that IGF2BP3 is associated with the aggressive phenotype of GBC. Mechanistically, IGF2BP3 activated the PAR2/AKT axis by stabilizing KLK5 mRNA in an m6A-dependent manner. The loss of let-7g-5p enhanced the expression of IGF2BP3 and improved GBC progression. Thus, IGF2BP3 plays a crucial role in GBC, and the let-7g-5p/IGF2BP3/KLK5/PAR2 axis may be a therapeutic target for GBC.

Lithocholic acid inhibits gallbladder cancer proliferation through interfering glutaminase-mediated glutamine metabolism

Lithocholic acid (LCA), one of the most common metabolic products of bile acids (BAs), is originally synthesized in the liver, stored in the gallbladder, and released to the intestine, where it assists absorption of lipid-soluble nutrients. LCA has recently emerged as a powerful reagent to inhibit tumorigenesis; however, the anti-tumor activity and molecular mechanisms of LCA in gallbladder cancer (GBC) remain poorly acknowledged. Here, we analyzed serum levels of LCA in human GBC and found that LCA was significantly downregulated in these patients, and reduced LCA levels were associated with poor clinical outcomes. Treatment of xenografts with LCA impeded tumor growth. Furthermore, LCA treatment in GBC cell lines decreased glutaminase (GLS) expression, glutamine (Gln) consumption, and GSH/GSSG and NADPH/NADP⁺ ratios, leading to cellular ferroptosis. In contrast, GLS overexpression in tumor cells fully restored GBC proliferation and decreased ROS imbalance, thus suppressing ferroptosis. Our findings reveal that LCA functions as a tumor-suppressive factor in GBC by downregulating GLS-mediated glutamine metabolism and subsequently inducing ferroptosis. This study may offer a new therapeutic strategy tailored to improve the treatment of GBC.

The Impact of Oxidative Stress and AKT Pathway on Cancer Cell Functions and Its Application to Natural Products

Oxidative stress and AKT serine-threonine kinase (AKT) are responsible for regulating several cell functions of cancer cells. Several natural products modulate both oxidative stress and AKT for anticancer effects. However, the impact of natural product-modulating oxidative stress and AKT on cell functions lacks systemic understanding. Notably, the contribution of regulating cell functions by AKT downstream effectors is not yet well integrated. This review explores the role of oxidative stress and AKT pathway (AKT/AKT effectors) on ten cell functions, including apoptosis, autophagy, endoplasmic reticulum stress, mitochondrial morphogenesis, ferroptosis, necroptosis, DNA damage response, senescence, migration, and cell-cycle progression. The impact of oxidative stress and AKT are connected to these cell functions through cell function mediators. Moreover, the AKT effectors related to cell functions are integrated. Based on this rationale, natural products with the modulating abilities for oxidative stress and AKT pathway exhibit the potential to regulate these cell functions, but some were rarely reported, particularly for AKT effectors. This review sheds light on understanding the roles of oxidative stress and AKT pathway in regulating cell functions, providing future directions for natural products in cancer treatment.