3D Culture Models with CRISPR Screens Reveal Hyperactive NRF2 as a Prerequisite for Spheroid Formation via Regulation of Proliferation and Ferroptosis

Human Organoids as an Emerging Tool for Genome Screenings

Over the last decade, a plethora of organoid models have been generated to recapitulate aspects of human development, disease, tissue homeostasis, and repair. Organoids representing multiple tissues have emerged and are typically categorized based on their origin. Tissue-derived organoids are established directly from tissue-resident stem/progenitor cells of either adult or fetal origin. Starting from pluripotent stem cells (PSCs), PSC-derived organoids instead recapitulate the developmental trajectory of a given organ. Gene editing technologies, particularly the CRISPR-Cas toolbox, have greatly facilitated gene manipulation experiments with considerable ease and scalability, revolutionizing organoid-based human biology research. Here, we review the recent adaptation of CRISPR-based screenings in organoids. We examine the strategies adopted to perform CRISPR screenings in organoids, discuss different screening scopes and readouts, and highlight organoid-specific challenges. We then discuss individual organoid-based genome screening studies that have uncovered novel genes involved in a variety of biological processes. We close by providing an outlook on how widespread adaptation of CRISPR screenings across the organoid field may be achieved, to ultimately leverage our understanding of human biology.

FAO-fueled OXPHOS and NRF2-mediated stress resilience in MICs drive lymph node metastasis

Metastasis is an inefficient process requiring cancer cells to adapt metabolically for survival and colonization in new environments. The contributions of tumor metabolic reprogramming to lymph node (LN) metastasis and its underlying mechanisms remain elusive. Through single-cell RNA sequencing, we identified rare metastasis-initiating cells (MICs) with stem-like properties that drive early LN metastasis. Integrated transcriptome, lipidomic, metabolomic, and functional analyses demonstrated that MICs depend on oxidative phosphorylation (OXPHOS) fueled by fatty acid oxidation (FAO) in the lipid-rich LN microenvironment. Mechanistically, the NRF2-SLC7A11 axis promotes glutathione synthesis to mitigate oxidative stress, thereby enhancing stress resistance and metastatic potential of MICs. Inhibition of NRF2-SLC7A11 reduced LN metastasis and sensitized tumors to cisplatin. Clinically, elevated NRF2-SLC7A11 expression was observed in tumors, with high expression correlating with LN metastasis, chemoresistance, and poor prognosis in esophageal squamous cell carcinoma (ESCC). These findings highlight the pivotal roles of FAO-fueled OXPHOS and NRF2 in LN metastasis and suggest targeting these pathways as a promising therapeutic strategy for metastatic ESCC.

Mechanisms of ferroptosis sensitization and resistance

Ferroptosis is an iron-dependent and oxidative form of non-apoptotic cell death with roles in development, homeostasis, and disease. Ferroptosis sensitivity can vary between cells, often for reasons that are not well understood. In this perspective, we describe the core ferroptosis mechanism and outline how changes in iron, redox, and lipid metabolism can alter ferroptosis sensitivity. We propose the concept of a ferroptosis sensitivity-resistance continuum to describe how different intrinsic and extrinsic factors interact to push cells toward a more ferroptosis-sensitive or ferroptosis-resistant state, with effects on development and diseases such as cancer.

The Type III Secretion System (T3SS) of Escherichia Coli Promotes Atherosclerosis in Type 2 Diabetes Mellitus

Large-scale studies indicate a strong relationship between the gut microbiome, type 2 diabetes mellitus (T2DM), and atherosclerotic cardiovascular disease (ASCVD). Here, a higher abundance of the type III secretion system (T3SS) virulence factors of Enterobacteriaceae/Escherichia-Shigella in patients with T2DM-related-ASCVD, which correlates with their atherosclerotic stenosis is reported. Overexpression of T3SS via Citrobacter rodentium (CR) infection in Apoe-/- T2DM mice exacerbated atherosclerotic lesion formation and increased gut permeability. Non-targeted metabolomic and proteomic analysis of mouse serum showed that T3SS caused abnormal glycerophospholipid metabolism in mice. Proteomics, RNA sequencing, and functional analyses showed that T3SS induced ferroptosis in intestinal epithelial cells, partly due to increased expression of ferritin heavy chains (FTH1). This findings first demonstrated that T3SS increases ferroptosis in intestinal epithelial cells, via disrupting the intestinal barrier and upregulation of phosphatidylcholine, thereby exacerbating T2DM-related ASCVD.

Warm-ischemia and cold storage induced modulation of ferroptosis observed in human hearts donated after circulatory death and brain death

We investigated ferroptosis, a type of programmed cell death mechanism, in human hearts donated after brain death (DBD) and those donated after circulatory death (DCD), focusing on warm ischemia time (WIT) and cold storage. A total of 24 hearts were procured, with six from the DBD group and 18 from the DCD group. The DCD group was divided into three subgroups, each containing six hearts, based on different WITs of 20, 40, and 60 min. All procured hearts were placed in cold storage for up to 6 h. Left ventricular biopsies were performed at 0, 2, 4, and 6 h. We measured ferroptosis regulators [glutathione peroxidase 4 (GPX4), acyl-CoA synthetase long chain family member 4 (ACSL4), and transferrin receptor], iron content (Fe2+ and Fe3+), and lipid peroxidation (malondialdehyde, MDA) in the cardiac tissue. Modulation of ferroptosis was observed in both DBD and DCD hearts. Warm ischemia injury increased myocardial vulnerability to ferroptotic cell death. For DBD hearts, up to 6 h of cold storage increases cardiac levels of MDA, iron content, and ACSL4, thereby increasing vulnerability to ferroptotic cell death. In contrast, for DCD hearts with a WIT of 40 min or more, warm ischemia injury was identified as the primary factor contributing to increased myocardial susceptibility to ferroptotic cell death. Ferroptosis may serve as a promising target to optimize cold preservation for DBD hearts. For DCD hearts, strategies to inhibit ferroptosis should focus on the early warm ischemia phase to assess donor heart quality and suitability for transplantation.NEW & NOTEWORTHY The first human heart research explored the effects of ischemia on the myocardial ferroptotic cell death mechanism. Prolonged cold storage increases the susceptibility of DBD hearts to ferroptotic cell death. In contrast, warm ischemic injury appears to be the main factor leading to the vulnerability of DCD heart ferroptosis. Targeting ferroptosis could be beneficial in optimizing cold preservation for DBD hearts. However, for DCD hearts, interventions should focus on the early phase of warm ischemia.

Advances in the Development of Ferroptosis-Inducing Agents for Cancer Treatment

Cancer is the main leading cause of death worldwide and poses a great threat to human life and health. Although pharmacological treatment with chemotherapy and immunotherapy is the main therapeutic strategy for cancer patients, there are still many shortcomings during the treatment such as incomplete killing of cancer cells and development of drug resistance. Emerging evidence indicates the promise of inducing ferroptosis for cancer treatment, particularly for eliminating aggressive malignancies that are resistant to conventional therapies. This review covers recent advances in important regulatory targets in the ferroptosis metabolic pathway and ferroptosis inducers (focusing mainly on the last 3 years) to delineate their design, mechanisms of action, and anticancer applications. To date, many compounds, including inhibitors, degraders, and active molecules from traditional Chinese medicine, have been demonstrated to have ferroptosis-inducing activity by targeting the different biomolecules in the ferroptosis pathway. However, strictly defined ferroptosis inducers have not yet been approved for clinical use; therefore, the discovery of new highly active, less toxic, and selective compounds remains the goal of further research in the coming years.

Dynamic GelMA/DNA Dual-Network Hydrogels Promote Woven Bone Organoid Formation and Enhance Bone Regeneration

Bone organoids, in vitro models mimicking native bone structure and function, rely on 3D stem cell culture for self-organization, differentiation, ECM secretion, and biomineralization, ultimately forming mineralized collagen hierarchies. However, their development is often limited by the lack of suitable matrices with optimal mechanical properties for sustained cell growth and differentiation. To address this, a dynamic DNA/Gelatin methacryloyl (GelMA) hydrogel (CGDE) is developed to recapitulate key biochemical and mechanical features of the bone ECM, providing a supportive microenvironment for bone organoid formation. This dual-network hydrogel is engineered through hydrogen bonding between DNA and GelMA, combined with GelMA network crosslinking, resulting in appropriate mechanical strength and enhanced viscoelasticity. During a 21-day 3D culture, the CGDE hydrogel facilitates cellular migration and self-organization, promoting woven bone organoid (WBO) formation via intramembranous ossification. These WBOs exhibit spatiotemporal architectures supporting dynamic mineralization and tissue remodeling. In vivo studies demonstrate that CGDE-derived WBOs exhibit self-adaptive properties, enabling rapid osseointegration within 4 weeks. This work highlights the CGDE hydrogel as a robust and scalable platform for bone organoid development, offering new insights into bone biology and innovative strategies for bone tissue regeneration.

Thirty years of NRF2: advances and therapeutic challenges

Over the last 30 years, NRF2 has evolved from being recognized as a transcription factor primarily involved in redox balance and detoxification to a well-appreciated master regulator of cellular proteostasis, metabolism and iron homeostasis. NRF2 plays a pivotal role in diverse pathologies, including cancer, and metabolic, inflammatory and neurodegenerative disorders. It exhibits a Janus-faced duality, safeguarding cellular integrity in normal cells against environmental insults to prevent disease onset, whereas in certain cancers, constitutively elevated NRF2 levels provide a tumour survival advantage, promoting progression, therapy resistance and metastasis. Advances in understanding the mechanistic regulation of NRF2 and its roles in human pathology have propelled the investigation of NRF2-targeted therapeutic strategies. This Review dissects the mechanistic intricacies of NRF2 signalling, its cross-talk with biological processes and its far-reaching implications for health and disease, highlighting key discoveries that have shaped innovative therapeutic approaches targeting NRF2.

Intratumour oxidative hotspots provide a niche for cancer cell dissemination

Intratumour heterogeneity represents the hierarchical integration of genetic, phenotypic and microenvironmental heterogeneity. Although single-cell sequencing has clarified genetic and phenotypic variability, the heterogeneity of nongenetic, microenvironmental factors remains elusive. Here, we developed T-AP1, a tumour-targeted probe tracking extracellular H2O2, which allows the visualization and characterization of tumour cells exposed to oxidative stress, a hallmark of cancer. T-AP1 identified actively budding intratumour regions as H2O2-rich microenvironments (H2O2 hotspots), which were primarily established by neutrophils. Mechanistically, tumour cells exposed to H2O2 underwent partial epithelial-mesenchymal transition through p38-MYC axis activation and migrated away from H2O2 hotspots. This escape mechanism was absent in normal epithelial cells but prevalent in most cancers except NRF2-hyperactivated tumours, which exhibited abrogated p38 responses and enhanced antioxidant programmes, thus revealing an intrinsic stress defence programme in cancers. Together, T-AP1 enabled the identification of H2O2 hotspots that provide a niche for cancer cell dissemination, offering insights into metastasis initiation.

NINJ1 in Cell Death and Ferroptosis: Implications for Tumor Invasion and Metastasis

NINJ1 was initially recognized for its role in nerve regeneration and cellular adhesion. Subsequent studies have uncovered its participation in cancer progression, where NINJ1 regulates critical steps in tumor metastasis, such as cell migration and invasion. More recently, NINJ1 has emerged as a multifunctional protein mediating plasma membrane rupture (PMR) in several lytic cell death processes, including apoptosis, necroptosis, and pyroptosis. However, its role in ferroptosis-an iron-dependent form of lytic cell death characterized by lipid peroxidation-remained unclear until 2024. Ferroptosis is a tumor suppression mechanism that may be particularly relevant to detached and metastatic cancer cells. This review explores the role of NINJ1 in tumor invasion and metastasis, focusing on its regulation of ferroptosis via a non-canonical mechanism distinct from other cell deaths. We discuss the process of ferroptosis and its implications for cancer invasion and metastasis. Furthermore, we review recent studies highlighting the diverse roles of NINJ1 in ferroptosis regulation, including its canonical function in PMR and its non-canonical function of modulating intracellular levels of glutathione (GSH) and coenzyme A (CoA) via interaction with xCT anti-porter. Given that ferroptosis has been associated with tumor suppression, metastasis, the elimination of treatment-resistant cancer cells, and tumor dormancy, NINJ1's modulation of ferroptosis presents a promising therapeutic target for inhibiting metastasis. Understanding the dual role of NINJ1 in promoting or restraining ferroptosis depending on cellular context could open avenues for novel anti-cancer strategies to enhance ferroptotic vulnerability in metastatic tumors.

Harnessing ferroptosis for precision oncology: challenges and prospects

The discovery of diverse molecular mechanisms of regulated cell death has opened new avenues for cancer therapy. Ferroptosis, a unique form of cell death driven by iron-catalyzed peroxidation of membrane phospholipids, holds particular promise for targeting resistant cancer types. This review critically examines current literature on ferroptosis, focusing on its defining features and therapeutic potential. We discuss how molecular profiling of tumors and liquid biopsies can generate extensive multi-omics datasets, which can be leveraged through machine learning-based analytical approaches for patient stratification. Addressing these challenges is essential for advancing the clinical integration of ferroptosis-driven treatments in cancer care.

MAPK14/p38α shapes the molecular landscape of endometrial cancer and promotes tumorigenic characteristics

The molecular underpinnings of high-grade endometrial carcinoma (HGEC) metastatic growth and survival are poorly understood. Here, we show that ascites-derived and primary tumor HGEC cell lines in 3D spheroid culture faithfully recapitulate key features of malignant peritoneal effusion and exhibit fundamentally distinct transcriptomic, proteomic, and metabolomic landscapes compared with conventional 2D monolayers. Using a genetic screening platform, we identify MAPK14 (which encodes the protein kinase p38α) as a specific requirement for HGEC in spheroid culture. MAPK14/p38α has broad roles in programming the phosphoproteome, transcriptome, and metabolome of HGEC spheroids, yet has negligible impact on monolayer cultures. MAPK14 promotes tumorigenicity in vivo and is specifically required to sustain a sub-population of spheroid cells that is enriched in cancer stemness markers. Therefore, spheroid growth of HGEC activates unique biological programs, including p38α signaling, that cannot be captured using 2D culture models and are highly relevant to malignant disease pathology.

Targeting ferroptosis to enhance the efficacy of mesenchymal stem cell-based treatments for intervertebral disc degeneration

Although mesenchymal stromal cell (MSC) implantation shows promise for repairing intervertebral disc (IVD) degeneration (IVDD), their limited retention within degenerative IVDs compromises therapeutic efficacy. The oxidative stress in the microenvironment of degenerated IVDs induces a surge in reactive oxygen species production within MSCs, disrupting the balance between oxidation and antioxidation, and ultimately inducing ferroptosis. Recent evidence has suggested that targeting ferroptosis in MSCs could enhance MSC retention, extend the survival of transplanted MSCs, and markedly delay the pathological progression of IVDD. By targeting ferroptosis, a novel approach emerges to boost the efficacy of MSC transplantation therapy for IVDD. In this review, current research on targeting ferroptosis in MSCs is discussed from various perspectives, including the targeting of specific genes and pathways, drug preconditioning, and hydrogel encapsulation. A detailed discussion on the effects of targeting ferroptosis in MSCs on the transplantation repair of degenerated IVDs is provided. Insights that could guide improvements in stem cell transplantation therapies are also offered. Significantly, this review presents specific ideas for our future foundational research. These insights outline promising avenues for future clinical translation and will contribute to developing and optimizing treatment strategies for MSC transplantation therapy, maximizing benefits for patients with lumbar IVDD.

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.

New insights into crosstalk between Nrf2 pathway and ferroptosis in lung disease

Ferroptosis is a distinctive process of cellular demise that is linked to amino acid metabolism, lipid oxidation, and iron oxidation. The ferroptosis cascade genes, which are closely associated with the onset of lung diseases, are among the regulatory targets of nuclear factor erythroid 2-related factor 2 (Nrf2). Although the regulation of ferroptosis is mostly mediated by Nrf2, the precise roles and underlying regulatory mechanisms of ferroptosis and Nrf2 in lung illness remain unclear. This review provides new insights from recent discoveries involving the modulation of Nrf2 and ferroptosis in a range of lung diseases. It also systematically describes regulatory mechanisms involving lipid peroxidation, intracellular antioxidant levels, ubiquitination of Nrf2, and expression of FSP1 and GPX4. Finally, it summarises active ingredients and drugs with potential for the treatment of lung diseases. With the overarching aim of expediting improvements in treatment, this review provides a reference for novel therapeutic mechanisms and offers suggestions for the development of new medications for a variety of lung disorders.

Lipid composition differentiates ferroptosis sensitivity between in vitro and in vivo systems

Ferroptosis is a regulated non-apoptotic cell death process characterized by iron-dependent lipid peroxidation. This process has recently emerged as a promising approach for cancer therapy. Peroxidation of polyunsaturated fatty acid-containing phospholipids (PUFA-PLs) is necessary for the execution of ferroptosis. Ferroptosis is normally suppressed by glutathione peroxidase 4 (GPX4), which reduces lipid hydroperoxides to lipid alcohols. Some evidence indicates that GPX4 may be a useful target for drug development, yet factors that govern GPX4 inhibitor sensitivity in vivo are poorly understood. We find that pharmacological and genetic loss of GPX4 function was sufficient to induce ferroptosis in multiple adherent ("2D") cancer cell cultures. However, reducing GPX4 protein levels did not affect tumor xenograft growth when these cells were implanted in mice. Furthermore, sensitivity to GPX4 inhibition was markedly reduced when cells were cultured as spheroids ("3D"). Mechanistically, growth in 3D versus 2D conditions reduced the abundance of PUFA-PLs. 3D culture conditions upregulated the monounsaturated fatty acid (MUFA) biosynthetic gene stearoyl-CoA desaturase (SCD). SCD-derived MUFAs appear to protect against ferroptosis in 3D conditions by displacing PUFAs from phospholipids. Various structurally related long chain MUFAs can inhibit ferroptosis through this PUFA-displacement mechanism. These findings suggest that growth-condition-dependent lipidome remodeling is an important mechanism governing GPX4 inhibitor effects. This resistance mechanism may specifically limit GPX4 inhibitor effectiveness in vivo .

Time-course characterization of whole-transcriptome dynamics of HepG2/C3A spheroids and its toxicological implications

Physiologically relevant in vitro models are a priority in predictive toxicology to replace and/or reduce animal experiments. The compromised toxicant metabolism of many immortalized human liver cell lines grown as monolayers as compared to in vivo metabolism limits their physiological relevance. However, recent efforts to culture liver cells in a 3D environment, such as spheroids, to better mimic the in vivo conditions, may enhance the toxicant metabolism of human liver cell lines. In this study, we characterized the dynamic changes in the transcriptome of HepG2/C3A hepatocarcinoma cell spheroids maintained in a clinostat system (CelVivo) to gain insight into the metabolic capacity of this model as a function of spheroid size and culture time. We assessed morphological changes (size, necrotic core), cell health, and proliferation rate from initial spheroid seeding to 35 days of continuous culture in conjunction with a time-course (0, 3, 7, 10, 14, 21, 28 days) of the transcriptome (TempO-Seq, BioSpyder). The phenotypic characteristics of HepG2/C3A growing in spheroids were comparable to monolayer growth until ∼Day 12 (Day 10-14) when a significant decrease in cell doubling rate was noted which was concurrent with down-regulation of cell proliferation and cell cycle pathways over this time period. Principal component analysis of the transcriptome data suggests that the Day 3, 7, and 10 spheroids are pronouncedly different from the Day 14, 21, and 28 spheroids in support of a biological transition time point during the long-term 3D spheroid cultures. The expression of genes encoding cellular components involved in toxicant metabolism and transport rapidly increased during the early time points of spheroids to peak at Day 7 or Day 10 as compared to monolayer cultures with a gradual decrease in expression with further culture, suggesting the most metabolically responsive time window for exposure studies. Overall, we provide baseline information on the cellular and molecular characterization, with a particular focus on toxicant metabolic capacity dynamics and cell growth, of HepG2/C3A 3D spheroid cultures over time.

SGK1 suppresses ferroptosis in ovarian cancer via NRF2-dependent and -independent pathways

High-grade serous ovarian cancer (HGSOC) is a highly aggressive disease often developing resistance to current therapies, necessitating new treatment strategies. Our study identifies SGK1, a key effector in the PI3K pathway, as a promising therapeutic target to exploit ferroptosis, a distinct form of cell death induced by iron overload and lipid peroxidation. Importantly, SGK1 activation, whether through high expression or the constitutively active SGK1-S422D mutation, confers resistance to ferroptosis in HGSOC. Conversely, SGK1 inhibition significantly enhances sensitivity to ferroptosis, as shown by increased PTGS2 expression (a ferroptosis marker), lipid peroxidation, and toxic-free iron levels. Remarkably, this enhanced cytotoxicity is reversed by ferrostatin-1 and the iron chelator deferoxamine, highlighting the pivotal roles of lipid peroxidation and iron dysregulation in the process. Mechanistically, SGK1 protects HGSOC cells from ferroptosis via NRF2-dependent pathways, promoting glutathione synthesis and iron homeostasis, and NRF2-independent pathways via mTOR/SREBP1/SCD1-mediated lipogenesis. Notably, pharmacological SGK1 inhibition sensitizes HGSOC xenograft models to ferroptosis induction, highlighting its therapeutic potential. These findings establish SGK1 as a critical regulator of ferroptosis and suggest targeting SGK1 alongside ferroptosis pathways as a potential therapeutic strategy for HGSOC patients.

Mimicking and analyzing the tumor microenvironment

The tumor microenvironment (TME) is increasingly appreciated to play a decisive role in cancer development and response to therapy in all solid tumors. Hypoxia, acidosis, high interstitial pressure, nutrient-poor conditions, and high cellular heterogeneity of the TME arise from interactions between cancer cells and their environment. These properties, in turn, play key roles in the aggressiveness and therapy resistance of the disease, through complex reciprocal interactions between the cancer cell genotype and phenotype, and the physicochemical and cellular environment. Understanding this complexity requires the combination of sophisticated cancer models and high-resolution analysis tools. Models must allow both control and analysis of cellular and acellular TME properties, and analyses must be able to capture the complexity at high depth and spatial resolution. Here, we review the advantages and limitations of key models and methods in order to guide further TME research and outline future challenges.

Ferroptosis in health and disease

Ferroptosis is a pervasive non-apoptotic form of cell death highly relevant in various degenerative diseases and malignancies. The hallmark of ferroptosis is uncontrolled and overwhelming peroxidation of polyunsaturated fatty acids contained in membrane phospholipids, which eventually leads to rupture of the plasma membrane. Ferroptosis is unique in that it is essentially a spontaneous, uncatalyzed chemical process based on perturbed iron and redox homeostasis contributing to the cell death process, but that it is nonetheless modulated by many metabolic nodes that impinge on the cells' susceptibility to ferroptosis. Among the various nodes affecting ferroptosis sensitivity, several have emerged as promising candidates for pharmacological intervention, rendering ferroptosis-related proteins attractive targets for the treatment of numerous currently incurable diseases. Herein, the current members of a Germany-wide research consortium focusing on ferroptosis research, as well as key external experts in ferroptosis who have made seminal contributions to this rapidly growing and exciting field of research, have gathered to provide a comprehensive, state-of-the-art review on ferroptosis. Specific topics include: basic mechanisms, in vivo relevance, specialized methodologies, chemical and pharmacological tools, and the potential contribution of ferroptosis to disease etiopathology and progression. We hope that this article will not only provide established scientists and newcomers to the field with an overview of the multiple facets of ferroptosis, but also encourage additional efforts to characterize further molecular pathways modulating ferroptosis, with the ultimate goal to develop novel pharmacotherapies to tackle the various diseases associated with - or caused by - ferroptosis.

Nrf2 in human cancers: biological significance and therapeutic potential

The nuclear factor-erythroid 2-related factor 2 (Nrf2) is able to control the redox balance in the cells responding to oxidative damage and other stress signals. The Nrf2 upregulation can elevate the levels of antioxidant enzymes to support against damage and death. In spite of protective function of Nrf2 in the physiological conditions, the stimulation of Nrf2 in the cancer has been in favour of tumorigenesis. Since the dysregulation of molecular pathways and mutations/deletions are common in tumors, Nrf2 can be a promising therapeutic target. The Nrf2 overexpression can prevent cell death in tumor and by increasing the survival rate of cancer cells, ensures the carcinogenesis. Moreover, the induction of Nrf2 can promote the invasion and metastasis of tumor cells. The Nrf2 upregulation stimulates EMT to increase cancer metastasis. Furthermore, regarding the protective function of Nrf2, its stimulation triggers chemoresistance. The natural products can regulate Nrf2 in the cancer therapy and reverse drug resistance. Moreover, nanostructures can specifically target Nrf2 signaling in cancer therapy. The current review discusses the potential function of Nrf2 in the proliferation, metastasis and drug resistance. Then, the capacity of natural products and nanostructures for suppressing Nrf2-mediated cancer progression is discussed.

TFE3 fusions direct an oncogenic transcriptional program that drives OXPHOS and unveils vulnerabilities in translocation renal cell carcinoma

Translocation renal cell carcinoma (tRCC) is an aggressive subtype of kidney cancer driven by TFE3 gene fusions, which act via poorly characterized downstream mechanisms. Here we report that TFE3 fusions transcriptionally rewire tRCCs toward oxidative phosphorylation (OXPHOS), contrasting with the highly glycolytic metabolism of most other renal cancers. This TFE3 fusion-driven OXPHOS program, together with heightened glutathione levels found in renal cancers, renders tRCCs sensitive to reductive stress - a metabolic stress state induced by an imbalance of reducing equivalents. Genome-scale CRISPR screening identifies tRCC-selective vulnerabilities linked to this metabolic state, including EGLN1, which hydroxylates HIF-1α and targets it for proteolysis. Inhibition of EGLN1 compromises tRCC cell growth by stabilizing HIF-1a and promoting metabolic reprogramming away from OXPHOS, thus representing a vulnerability to OXPHOS-dependent tRCC cells. Our study defines a distinctive tRCC-essential metabolic program driven by TFE3 fusions and nominates EGLN1 inhibition as a therapeutic strategy to counteract fusion-induced metabolic rewiring.

CRISPR screens in 3D tumourspheres identified miR-4787-3p as a transcriptional start site miRNA essential for breast tumour-initiating cell growth

Our study employs pooled CRISPR screens, integrating 2D and 3D culture models, to identify miRNAs critical in Breast Cancer (BC) tumoursphere formation. These screens combine with RNA-seq experiments allowing identification of miRNA signatures and targets essential for tumoursphere growth. miR-4787-3p exhibits significant up-regulation in BC, particularly in basal-like BCs, suggesting its association with aggressive disease. Surprisingly, despite its location within the 5'UTR of a protein coding gene, which defines DROSHA-independent transcription start site (TSS)-miRNAs, we find it dependant on both DROSHA and DICER1 for maturation. Inhibition of miR-4787-3p hinders tumoursphere formation, highlighting its potential as a therapeutic target in BC. Our study proposes elevated miR-4787-3p expression as a potential prognostic biomarker for adverse outcomes in BC. We find that protein-coding genes positively selected in the CRISPR screens are enriched of miR-4787-3p targets. Of these targets, we select ARHGAP17, FOXO3A, and PDCD4 as known tumour suppressors in cancer and experimentally validate the interaction of miR-4787-3p with their 3'UTRs. Our work illuminates the molecular mechanisms underpinning miR-4787-3p's oncogenic role in BC. These findings advocate for clinical investigations targeting miR-4787-3p and underscore its prognostic significance, offering promising avenues for tailored therapeutic interventions and prognostic assessments in BC.

MAPK14 /p38α Shapes the Molecular Landscape of Endometrial Cancer and promotes Tumorigenic Characteristics

The molecular underpinnings of H igh G rade E ndometrial C arcinoma (HGEC) metastatic growth and survival are poorly understood. Here we show that ascites-derived and primary tumor HGEC cell lines in 3D spheroid culture faithfully recapitulate key features of malignant peritoneal effusion and exhibit fundamentally distinct transcriptomic, proteomic and metabolomic landscapes when compared with conventional 2D monolayers. Using genetic screening platform we identify MAPK14 (which encodes the protein kinase p38α) as a specific requirement for HGEC in spheroid culture. MAPK14 /p38α has broad roles in programing the phosphoproteome, transcriptome and metabolome of HGEC spheroids, yet has negligible impact on monolayer cultures. MAPK14 promotes tumorigenicity in vivo and is specifically required to sustain a sub-population of spheroid cells that is enriched in cancer stemness markers. Therefore, spheroid growth of HGEC activates unique biological programs, including p38α signaling, that cannot be captured using 2D culture models and are highly relevant to malignant disease pathology.

The cell biology of ferroptosis

Ferroptosis is a non-apoptotic cell death mechanism characterized by iron-dependent membrane lipid peroxidation. Here, we review what is known about the cellular mechanisms mediating the execution and regulation of ferroptosis. We first consider how the accumulation of membrane lipid peroxides leads to the execution of ferroptosis by altering ion transport across the plasma membrane. We then discuss how metabolites and enzymes that are distributed in different compartments and organelles throughout the cell can regulate sensitivity to ferroptosis by impinging upon iron, lipid and redox metabolism. Indeed, metabolic pathways that reside in the mitochondria, endoplasmic reticulum, lipid droplets, peroxisomes and other organelles all contribute to the regulation of ferroptosis sensitivity. We note how the regulation of ferroptosis sensitivity by these different organelles and pathways seems to vary between different cells and death-inducing conditions. We also highlight transcriptional master regulators that integrate the functions of different pathways and organelles to modulate ferroptosis sensitivity globally. Throughout this Review, we highlight open questions and areas in which progress is needed to better understand the cell biology of ferroptosis.

Kellerin alleviates cerebral ischemic injury by inhibiting ferroptosis via targeting Akt-mediated transcriptional activation of Nrf2

BACKGROUND

Ischemic stroke (IS) is characterized as a detrimental cerebrovascular disease with high mortality and disability. Ferroptosis is a novel mechanism involved in neuronal death. There is a close connection between IS and ferroptosis, and inhibiting ferroptosis may provide an effective strategy for treating IS. Our previous investigations have discovered that kellerin, the active compound of Ferula sinkiangensis K. M. Shen, possesses the capability to shield against cerebral ischemia injury.

PURPOSE

Our objective is to clarify the relationship between the neuroprotective properties of kellerin against IS and its ability to modulate ferroptosis, and investigate the underlying regulatory pathway.

STUDY DESIGN

We investigated the impact and mechanism of kellerin in C57BL/6 mice underwent middle cerebral artery occlusion/reperfusion (MCAO/R) as well as SH-SY5Y cells exposed to oxygen-glucose deprivation/ re-oxygenation (OGD/R).

METHODS

The roles of kellerin on neurological severity, cerebral infarction and edema were investigated in vivo. The regulatory impacts of kellerin on ferroptosis, mitochondrial damage and Akt/Nrf2 pathway were explored. Molecular docking combined with drug affinity responsive target stability assay (DARTS) and cellular thermal shift assay (CETSA) were performed to analyze the potential target proteins for kellerin.

RESULTS

Kellerin protected against IS and inhibited ferroptosis in vivo. Meanwhile, kellerin improved the neuronal damage caused by OGD/R and suppressed ferroptosis by inhibiting the production of mitochondrial ROS in vitro. Further we found that kellerin directly interacted with Akt and enhanced its phosphorylation, leading to the increase of Nrf2 nuclear translocation and its downstream antioxidant genes expression. Moreover, kellerin's inhibitory effect on ferroptosis and mitochondrial ROS release was eliminated by inhibiting Akt/Nrf2 pathway.

CONCLUSIONS

Our study firstly demonstrates that the neuroprotective properties of kellerin against IS are related to suppressing ferroptosis through inhibiting the production of mitochondrial ROS, in which its modulation on Akt-mediated transcriptional activation of Nrf2 plays an important role. This finding shed light on the potential mechanism that kellerin exerts therapeutic effects in IS.

Unlocking the anticancer activity of gambogic acid: a shift towards ferroptosis via a GSH/Trx dual antioxidant system

Nuclear factor erythroid 2-related factor 2 (Nrf2) plays a crucial role in ferroptosis by regulating the cellular antioxidant response and maintaining redox balance. However, compounds that induce ferroptosis through dual antioxidant pathways based on Nrf2 have not been fully explored. In our study, we investigated the impact of Gambogic acid (GA) on MCF-7 cells and HepG2 cells in vitro. The cytotoxicity, colony formation assay and cell cycle assay demonstrated potent tumor-killing ability of GA, while its effect was rescued by ferroptosis inhibitors. Furthermore, RNA sequencing revealed the enrichment of ferroptosis pathway mediated by GA. In terms of ferroptosis indicators detection, evidences for GA were provided including reactive oxygen species (ROS) accumulation, alteration in mitochondrial membrane potential (MMP), disappearance of mitochondrial cristae, lipid peroxidation induction, malondialdehyde (MDA) accumulation promotion, iron ion accumulation as well as glutathione (GSH)/thioredoxin (Trx) depletion. Notably, Ferrostatin-1 (Fer-1) and Liproxstatin-1 (Lip-1) successfully rescued GA-induced MDA accumulation. In terms of mechanism, Nrf2 was found to play a pivotal role in GA-induced ferroptosis by inducing protein alterations through the iron metabolism pathway and GSH/Trx dual antioxidant pathway. Furthermore, GA exerted good antitumor activity in vivo through GSH/Trx dual antioxidant pathway, and Fer-1 significantly attenuated its efficacy. In conclusion, our findings first provided new evidence for GA as an inducer of ferroptosis, and Nrf2-mediated GSH/Trx dual antioxidant system played an important role in GA-induced ferroptosis.

Identification of a set of genes potentially responsible for resistance to ferroptosis in lung adenocarcinoma cancer stem cells

Scientific literature supports the evidence that cancer stem cells (CSCs) retain inside low reactive oxygen species (ROS) levels and are, therefore, less susceptible to cell death, including ferroptosis, a type of cell death dependent on iron-driven lipid peroxidation. A collection of lung adenocarcinoma (LUAD) primary cell lines derived from malignant pleural effusions (MPEs) of patients was used to obtain 3D spheroids enriched for stem-like properties. We observed that the ferroptosis inducer RSL3 triggered lipid peroxidation and cell death in LUAD cells when grown in 2D conditions; however, when grown in 3D conditions, all cell lines underwent a phenotypic switch, exhibiting substantial resistance to RSL3 and, therefore, protection against ferroptotic cell death. Interestingly, this phenomenon was reversed by disrupting 3D cells and growing them back in adherence, supporting the idea of CSCs plasticity, which holds that cancer cells have the dynamic ability to transition between a CSC state and a non-CSC state. Molecular analyses showed that ferroptosis resistance in 3D spheroids correlated with an increased expression of antioxidant genes and high levels of proteins involved in iron storage and export, indicating protection against oxidative stress and low availability of iron for the initiation of ferroptosis. Moreover, transcriptomic analyses highlighted a novel subset of genes commonly modulated in 3D spheroids and potentially capable of driving ferroptosis protection in LUAD-CSCs, thus allowing to better understand the mechanisms of CSC-mediated drug resistance in tumors.

Ferroptosis is an effective strategy for cancer therapy

Ferroptosis is a form of intracellular iron-dependent cell death that differs from necrosis, autophagy and apoptosis. Intracellular iron mediates Fenton reaction resulting in lipid peroxidation production, which in turn promotes cell death. Although cancer cell exhibit's ability to escape ferroptosis by multiple pathways such as SLC7A11, GPX4, induction of ferroptosis could inhibit cancer cell proliferation, migration and invasion. In tumor microenvironment, ferroptosis could affect immune cell (T cells, macrophages etc.) activity, which in turn regulates tumor immune escape. In addition, ferroptosis in cancer cells could activate immune cell activity by antigen processing and presentation. Therefore, ferroptosis could be an effective strategy for cancer therapy such as chemotherapy, radiotherapy, and immunotherapy. In this paper, we reviewed the role of ferroptosis on tumor progression and therapy, which may provide a strategy for cancer treatment.

Fisetin Suppresses Atherosclerosis by Inhibiting Ferroptosis-Related Oxidative Stress in Apolipoprotein E Knockout Mice

INTRODUCTION

Fisetin has been demonstrated to inhibit the occurrence of atherosclerosis; however, the mechanism of fisetin suppressing atherosclerosis remains elusive.

METHODS

The function of fisetin in the inhibition of atherosclerosis was evaluated by hematoxylin and eosin and Oil Red O staining in ApoE-/- mice. Molecular biomarkers of atherosclerosis progression were detected by Western blot and qPCR. Moreover, the inhibition of atherosclerosis on oxidative stress and ferroptosis was evaluated by immunofluorescence staining, qPCR, and Western blot assays.

RESULTS

The obtained results showed that serum lipid was attenuated and consequentially the formation of atherosclerosis was also suppressed by fisetin in ApoE-/- mice. Exploration of the mechanism revealed that molecular biomarkers of atherosclerosis were decreased under fisetin treatment. The level of reactive oxygen species and malondialdehyde declined, while the activity of superoxide dismutases and glutathione peroxidase was increased under the fisetin treatment. Additionally, the suppressor of ferroptosis, glutathione peroxidase 4 proteins, was elevated. The ferritin was decreased in the aortic tissues treated with fisetin.

CONCLUSIONS

In summary, fisetin attenuated the formation of atherosclerosis through the inhibition of oxidative stress and ferroptosis in the aortic tissues of ApoE-/- mice.

Emerging mechanisms of ferroptosis and its implications in lung cancer

ABSTRACT

Lung cancer is one of the most common malignancies and has the highest number of deaths among all cancers. Despite continuous advances in medical strategies, the overall survival of lung cancer patients is still low, probably due to disease progression or drug resistance. Ferroptosis is an iron-dependent form of regulated cell death triggered by the lethal accumulation of lipid peroxides, and its dysregulation is implicated in cancer development. Preclinical evidence has shown that targeting the ferroptosis pathway could be a potential strategy for improving lung cancer treatment outcomes. In this review, we summarize the underlying mechanisms and regulatory networks of ferroptosis in lung cancer and highlight ferroptosis-targeting preclinical attempts to provide new insights for lung cancer treatment.

Thiol starvation triggers melanoma state switching in an ATF4 and NRF2-dependent manner

The cystine/glutamate antiporter xCT is an important source of cysteine for cancer cells. Once taken up, cystine is reduced to cysteine and serves as a building block for the synthesis of glutathione, which efficiently protects cells from oxidative damage and prevents ferroptosis. As melanomas are particularly exposed to several sources of oxidative stress, we investigated the biological role of cysteine and glutathione supply by xCT in melanoma. xCT activity was abolished by genetic depletion in the Tyr::CreER; BrafCA; Ptenlox/+ melanoma model and by acute cystine withdrawal in melanoma cell lines. Both interventions profoundly impacted melanoma glutathione levels, but they were surprisingly well tolerated by murine melanomas in vivo and by most human melanoma cell lines in vitro. RNA sequencing of human melanoma cells revealed a strong adaptive upregulation of NRF2 and ATF4 pathways, which orchestrated the compensatory upregulation of genes involved in antioxidant defence and de novo cysteine biosynthesis. In addition, the joint activation of ATF4 and NRF2 triggered a phenotypic switch characterized by a reduction of differentiation genes and induction of pro-invasive features, which was also observed after erastin treatment or the inhibition of glutathione synthesis. NRF2 alone was capable of inducing the phenotypic switch in a transient manner. Together, our data show that cystine or glutathione levels regulate the phenotypic plasticity of melanoma cells by elevating ATF4 and NRF2.

Induction of stearoyl-CoA desaturase confers cell density-dependent ferroptosis resistance in melanoma

Ferroptosis is a form of regulated cell death that is induced by inhibiting glutathione peroxidase 4 (GPX4), which eliminates lipid peroxidation. Ferroptosis induction is influenced by the cell environment. However, the cellular states altering ferroptosis susceptibility remain largely unknown. We found that melanoma cell lines became resistant to ferroptosis as cell density increased. Comparative transcriptome and metabolome analyses revealed that cell density-dependent ferroptosis resistance was coupled with a shift toward a lipogenic phenotype accompanied by strong induction of stearoyl-CoA desaturase (SCD). Database analysis of gene dependency across hundreds of cancer cell lines uncovered a negative correlation between GPX4 and SCD dependency. Importantly, SCD inhibition, either pharmacologically or through genetic knockout, sensitized melanoma cells to GPX4 inhibition, thereby attenuating ferroptosis resistance in cells at high density. Our findings indicate that transition to an SCD-inducing, lipogenic cell state produces density-dependent resistance to ferroptosis, which may provide a therapeutic strategy against melanoma.

[What is the Initiating Reaction for the Lipid Radical Chain Reaction System That Can Induce Ferroptotic Cell Death at the Lower Oxygen Content?]

The neural cell death in cerebral infarction is suggested to be ferroptosis-like cell death, involving the participation of 15-lipoxygenase (15-LOx). Ferroptosis is induced by lipid radical species generated through the one-electron reduction of lipid hydroperoxides, and it has been shown to propagate intracellularly and intercellularly. At lower oxygen concentration, it appeared that both regiospecificity and stereospecificity of conjugated diene moiety in lipoxygenase-catalysed lipid hydroperoxidation are drastically lost. As a result, in the reaction with linoleic acid, the linoleate 9-peroxyl radical-ferrous lipoxygenase complex dissolves into the linoleate 9-peroxyl radical and ferrous 15-lipoxygenase. Subsequently, the ferrous 15-lipoxygenase then undergoes one-electron reduction of 13-hydroperoxy octadecadienoic acid, generating an alkoxyl radical (pseudoperoxidase reaction). A part of the produced lipid alkoxyl radicals undergoes cleavage of C-C bonds, liberating small molecular hydrocarbon radicals. Particularly, in ω-3 polyunsaturated fatty acids, which are abundant in the vascular and nervous systems, the liberation of small molecular hydrocarbon radicals was more pronounced compared to ω-6 polyunsaturated fatty acids. The involvement of these small molecular hydrocarbon radicals in the propagation of membrane lipid damage is suggested.

The Role of Oxidative Stress in Tumorigenesis and Progression

Oxidative stress refers to the imbalance between the production of reactive oxygen species (ROS) and the endogenous antioxidant defense system. Its involvement in cell senescence, apoptosis, and series diseases has been demonstrated. Advances in carcinogenic research have revealed oxidative stress as a pivotal pathophysiological pathway in tumorigenesis and to be involved in lung cancer, glioma, hepatocellular carcinoma, leukemia, and so on. This review combs the effects of oxidative stress on tumorigenesis on each phase and cell fate determination, and three features are discussed. Oxidative stress takes part in the processes ranging from tumorigenesis to tumor death via series pathways and processes like mitochondrial stress, endoplasmic reticulum stress, and ferroptosis. It can affect cell fate by engaging in the complex relationships between senescence, death, and cancer. The influence of oxidative stress on tumorigenesis and progression is a multi-stage interlaced process that includes two aspects of promotion and inhibition, with mitochondria as the core of regulation. A deeper and more comprehensive understanding of the effects of oxidative stress on tumorigenesis is conducive to exploring more tumor therapies.

The pleiotropic functions of reactive oxygen species in cancer

Cellular redox homeostasis is an essential, dynamic process that ensures the balance between reducing and oxidizing reactions within cells and thus has implications across all areas of biology. Changes in levels of reactive oxygen species can disrupt redox homeostasis, leading to oxidative or reductive stress that contributes to the pathogenesis of many malignancies, including cancer. From transformation and tumor initiation to metastatic dissemination, increasing reactive oxygen species in cancer cells can paradoxically promote or suppress the tumorigenic process, depending on the extent of redox stress, its spatiotemporal characteristics and the tumor microenvironment. Here we review how redox regulation influences tumorigenesis, highlighting therapeutic opportunities enabled by redox-related alterations in cancer cells.

Loss of Myo19 increases metastasis by enhancing microenvironmental ROS gradient and chemotaxis

Tumor metastasis involves cells migrating directionally in response to external chemical signals. Reactive oxygen species (ROS) in the form of H2O2 has been demonstrated as a chemoattractant for neutrophils but its spatial characteristics in tumor microenvironment and potential role in tumor cell dissemination remain unknown. Here we investigate the spatial ROS distribution in 3D tumor spheroids and identify a ROS concentration gradient in spheroid periphery, which projects into a H2O2 gradient in tumor microenvironment. We further reveal the role of H2O2 gradient to induce chemotaxis of tumor cells by activating Src and subsequently inhibiting RhoA. Finally, we observe that the absence of mitochondria cristae remodeling proteins including the mitochondria-localized actin motor Myosin 19 (Myo19) enhances ROS gradient and promotes tumor dissemination. Myo19 downregulation is seen in many tumors, and Myo19 expression is negatively associated with tumor metastasis in vivo. Together, our study reveals the chemoattractant role of tumor microenvironmental ROS and implies the potential impact of mitochondria cristae disorganization on tumor invasion and metastasis.

Antioxidant Systems as Modulators of Ferroptosis: Focus on Transcription Factors

Ferroptosis is a type of programmed cell death that differs from apoptosis, autophagy, and necrosis and is related to several physio-pathological processes, including tumorigenesis, neurodegeneration, senescence, blood diseases, kidney disorders, and ischemia-reperfusion injuries. Ferroptosis is linked to iron accumulation, eliciting dysfunction of antioxidant systems, which favor the production of lipid peroxides, cell membrane damage, and ultimately, cell death. Thus, signaling pathways evoking ferroptosis are strongly associated with those protecting cells against iron excess and/or lipid-derived ROS. Here, we discuss the interaction between the metabolic pathways of ferroptosis and antioxidant systems, with a particular focus on transcription factors implicated in the regulation of ferroptosis, either as triggers of lipid peroxidation or as ferroptosis antioxidant defense pathways.

Impaired bone morphogenetic protein (BMP) signaling pathways disrupt decidualization in endometriosis

Endometriosis is linked to increased infertility and pregnancy complications due to defective endometrial decidualization. We hypothesized that identification of altered signaling pathways during decidualization could identify the underlying cause of infertility and pregnancy complications. Our study reveals that transforming growth factor β (TGFβ) pathways are impaired in the endometrium of individuals with endometriosis, leading to defective decidualization. Through detailed transcriptomic analyses, we discovered abnormalities in TGFβ signaling pathways and key regulators, such as SMAD4, in the endometrium of affected individuals. We also observed compromised activity of bone morphogenetic proteins (BMP), a subset of the TGFβ family, that control endometrial receptivity. Using 3-dimensional models of endometrial stromal and epithelial assembloids, we showed that exogenous BMP2 improved decidual marker expression in individuals with endometriosis. Our findings reveal dysfunction of BMP/SMAD signaling in the endometrium of individuals with endometriosis, explaining decidualization defects and subsequent pregnancy complications in these individuals.

Quantitative Assessment of the Post-translational Modifications of Human Serum Albumin by Dimethyl Trisulfide

Some bacteria, such as Fusobacterium nucleatum, act as dimethyl trisulfide (DMTS) producers in the host in vivo. DMTS acts as a sulfane sulfur donor and chemically modifies the sulfhydryl groups. This study explored the post-translational modifications of human serum albumin using DMTS. Quantitative assessments were conducted on mixed disulfides of mercaptoalbumin with mercaptomethane (Alb-SS-CH3) and albumin hydropersulfide (Alb-SSH) as post-translationally modified species. The hydropersulfide group was alkylated with iodoacetamide, resulting in the formation of an albumin-mercaptoacetamide mixed disulfide. The mixed disulfides were subsequently reduced with tris(2-carboxyethyl)phosphine, and the liberated mercaptomethane and mercaptoacetamide were fluorescently labeled with 4-fluoro-7-sulfamoylbenzofurazan (ABD-F). Quantification was performed using HPLC with fluorescence detection. Using this methodology, we examined the formation of Alb-SS-CH3 and Alb-SSH via the reaction between 4% human serum albumin and DMTS at 10-100 µM concentrations. Approximately two molecules of Alb-SS-CH3 and one molecule of Alb-SSH were generated from one DMTS molecule. Moreover, hydrogen sulfide was identified as an intermediate, suggesting its generation and subsequent reaction with intraprotein disulfide bonds, leading to the production of Alb-SSH. These results suggest the production of DMTS in humans in vivo should be involved in the elevation of Alb-SS-CH3 and Alb-SSH contents in plasma samples.

Regulation of antioxidants in cancer

Scientists in this field often joke, "If you don't have a mechanism, say it's ROS." Seemingly connected to every biological process ever described, reactive oxygen species (ROS) have numerous pleiotropic roles in physiology and disease. In some contexts, ROS act as secondary messengers, controlling a variety of signaling cascades. In other scenarios, they initiate damage to macromolecules. Finally, in their worst form, ROS are deadly to cells and surrounding tissues. A set of molecules with detoxifying abilities, termed antioxidants, is the direct counterpart to ROS. Notably, antioxidants exist in the public domain, touted as a "cure-all" for diseases. Research has disproved many of these claims and, in some cases, shown the opposite. Of all the diseases, cancer stands out in its paradoxical relationship with antioxidants. Although the field has made numerous strides in understanding the roles of antioxidants in cancer, many questions remain.

Guilu-Erxian-Glue alleviates Tripterygium wilfordii polyglycoside-induced oligoasthenospermia in rats by resisting ferroptosis via the Keap1/Nrf2/GPX4 signaling pathway

CONTEXT

Guilu-Erxian-Glue (GLEXG) is a traditional Chinese formula used to improve male reproductive dysfunction.

OBJECTIVE

To investigate the ferroptosis resistance of GLEXG in the improvement of semen quality in the oligoasthenospermia (OAS) rat model.

MATERIALS AND METHODS

Male Sprague-Dawley (SD) rats were administered Tripterygium wilfordii polyglycoside, a compound extracted from Tripterygium wilfordii Hook F. (Celastraceae), at a dose of 40 mg/kg/day, to establish an OAS model. Fifty-four SD rats were randomly divided into six groups: sham, model, low-dose GLEXG (GLEXGL, 0.25 g/kg/day), moderate-dose GLEXG (GLEXGM, 0.50 g/kg/day), high-dose GLEXG (GLEXGH, 1.00 g/kg/day) and vitamin E (0.01 g/kg/day) group. The semen quality, structure and function of sperm mitochondria, histopathology, levels of oxidative stress and iron, and mRNA levels and protein expression in the Keap1/Nrf2/GPX4 pathway, were analyzed.

RESULTS

Compared with the model group, GLEXGH significantly improved sperm concentration (35.73 ± 15.42 vs. 17.40 ± 4.12, p < 0.05) and motility (58.59 ± 11.06 vs. 28.59 ± 9.42, p < 0.001), and mitigated testicular histopathology. Moreover, GLEXGH markedly reduced the ROS level (5684.28 ± 1345.47 vs. 15500.44 ± 2307.39, p < 0.001) and increased the GPX4 level (48.53 ± 10.78 vs. 23.14 ± 11.04, p < 0.01), decreased the ferrous iron level (36.31 ± 3.66 vs. 48.64 ± 7.74, p < 0.05), and rescued sperm mitochondrial morphology and potential via activating the Keap1/Nrf2/GPX4 pathway.

DISCUSSION AND CONCLUSIONS

Ferroptosis resistance from GLEXG might be driven by activation of the Keap1/Nrf2/GPX4 pathway. Targeting ferroptosis is a novel approach for OAS therapy.

Impaired bone morphogenetic protein (BMP) signaling pathways disrupt decidualization in endometriosis

Endometriosis is linked to increased infertility and pregnancy complications due to defective endometrial decidualization. We hypothesized that identification of altered signaling pathways during decidualization could identify the underlying cause of infertility and pregnancy complications. Our study reveals that transforming growth factor β (TGFβ) pathways are impaired in the endometrium of individuals with endometriosis, leading to defective decidualization. Through detailed transcriptomic analyses, we discovered abnormalities in TGFβ signaling pathways and key regulators, such as SMAD4, in the endometrium of affected individuals. We also observed compromised activity of bone morphogenetic proteins (BMP), a subset of the TGFβ family, that control endometrial receptivity. Using 3-dimensional models of endometrial stromal and epithelial assembloids, we showed that exogenous BMP2 improved decidual marker expression in individuals with endometriosis. Our findings unveil a previously unidentified dysfunction in BMP/SMAD signaling in the endometrium of individuals with endometriosis, explaining decidualization defects and subsequent pregnancy complications in these individuals.

CRISPR-Cas System Is an Effective Tool for Identifying Drug Combinations That Provide Synergistic Therapeutic Potential in Cancers

Despite numerous efforts, the therapeutic advancement for neuroblastoma and other cancer treatments is still ongoing due to multiple challenges, such as the increasing prevalence of cancers and therapy resistance development in tumors. To overcome such obstacles, drug combinations are one of the promising applications. However, identifying and implementing effective drug combinations are critical for achieving favorable treatment outcomes. Given the enormous possibilities of combinations, a rational approach is required to predict the impact of drug combinations. Thus, CRISPR-Cas-based and other approaches, such as high-throughput pharmacological and genetic screening approaches, have been used to identify possible drug combinations. In particular, the CRISPR-Cas system (Clustered Regularly Interspaced Short Palindromic Repeats) is a powerful tool that enables us to efficiently identify possible drug combinations that can improve treatment outcomes by reducing the total search space. In this review, we discuss the rational approaches to identifying, examining, and predicting drug combinations and their impact.

[Research Progress of Nrf2 and Ferroptosis in Tumor Drug Resistance]

Lung cancer is one of the most common cancers in the world, and its treatment strategy is mainly surgery combined with radiotherapy and chemotherapy. However, long-term chemotherapy will result in drug resistance, which is also one of the difficulties in the treatment of lung cancer. Ferroptosis is an iron-dependent and lipid peroxidation-driven non-apoptotic cell death cascade, occurring when there is an imbalance of redox homeostasis in the cell. Nuclear factor erythroid 2-related factor 2 (Nrf2) is key for cellular antioxidant responses. Numerous studies suggest that Nrf2 assumes an extremely important role in regulation of ferroptosis, for its various functions in iron, lipid, and amino acid metabolism, and so on. In this review, a brief overview of the research progress of ferroptosis over the past decade will be presented. In particular, the mechanism of ferroptosis and the regulation of ferroptosis by Nrf2 will be discussed, as well as the role of the Nrf2 pathway and ferroptosis in tumor drug resistance, which will provide new research directions for the treatment of drug-resistant lung cancer patients.
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Genetic and Functional Modifications Associated with Ovarian Cancer Cell Aggregation and Limited Culture Conditions

The aggregation of cancer cells provides a survival signal for disseminating cancer cells; however, the underlying molecular mechanisms have yet to be elucidated. Using qPCR gene arrays, this study investigated the changes in cancer-specific genes as well as genes regulating mitochondrial quality control, metabolism, and oxidative stress in response to aggregation and hypoxia in our progressive ovarian cancer models representing slow- and fast-developing ovarian cancer. Aggregation increased the expression of anti-apoptotic, stemness, epithelial-mesenchymal transition (EMT), angiogenic, mitophagic, and reactive oxygen species (ROS) scavenging genes and functions, and decreased proliferation, apoptosis, metabolism, and mitochondrial content genes and functions. The incorporation of stromal vascular cells (SVF) from obese mice into the spheroids increased DNA repair and telomere regulatory genes that may represent a link between obesity and ovarian cancer risk. While glucose had no effect, glutamine was essential for aggregation and supported proliferation of the spheroid. In contrast, low glucose and hypoxic culture conditions delayed adhesion and outgrowth capacity of the spheroids independent of their phenotype, decreased mitochondrial mass and polarity, and induced a shift of mitochondrial dynamics towards mitophagy. However, these conditions did not reduce the appearance of polarized mitochondria at adhesion sites, suggesting that adhesion signals that either reversed mitochondrial fragmentation or induced mitobiogenesis can override the impact of low glucose and oxygen levels. Thus, the plasticity of the spheroids' phenotype supports viability during dissemination, allows for the adaptation to changing conditions such as oxygen and nutrient availability. This may be critical for the development of an aggressive cancer phenotype and, therefore, could represent druggable targets for clinical interventions.

Impaired bone morphogenetic protein signaling pathways disrupt decidualization in endometriosis

It is hypothesized that impaired endometrial decidualization contributes to decreased fertility in individuals with endometriosis. To identify the molecular defects that underpin defective decidualization in endometriosis, we subjected endometrial stromal cells from individuals with or without endometriosis to time course in vitro decidualization with estradiol, progesterone, and 8-bromo-cyclic-AMP (EPC) for 2, 4, 6, or 8 days. Transcriptomic profiling identified differences in key pathways between the two groups, including defective bone morphogenetic protein (BMP)/SMAD4 signaling (ID2, ID3, FST), oxidate stress response (NFE2L2, ALOX15, SLC40A1), and retinoic acid signaling pathways (RARRES, RARB, ALDH1B1). Genome-wide binding analyses identified an altered genomic distribution of SMAD4 and H3K27Ac in the decidualized stromal cells from individuals without endometriosis relative to those with endometriosis, with target genes enriched in pathways related to signaling by transforming growth factor β (TGFβ), neurotrophic tyrosine kinase receptors (NTRK), and nerve growth factor (NGF)-stimulated transcription. We found that direct SMAD1/5/4 target genes control FOXO, PI3K/AKT, and progesterone-mediated signaling in decidualizing cells and that BMP2 supplementation in endometriosis patient-derived assembloids elevated the expression of decidualization markers. In summary, transcriptomic and genome-wide binding analyses of patient-derived endometrial cells and assembloids identified that a functional BMP/SMAD1/5/4 signaling program is crucial for engaging decidualization.

Fabricating a low-temperature synthesized graphene-cellulose acetate-sodium alginate scaffold for the generation of ovarian cancer spheriod and its drug assessment

3D cell culture can mimic tumor pathophysiology, which reflects cellular morphology and heterogeneity, strongly influencing gene expression, cell behavior, and intracellular signaling. It supports cell-cell and cell-matrix interaction, cell attachment, and proliferation, resulting in rapid and reliable drug screening models. We have generated an ovarian cancer spheroid in interconnected porous scaffolds. The scaffold is fabricated using low-temperature synthesized graphene, cellulose acetate, and sodium alginate. Graphene nanosheets enhance cell proliferation and aggregation, which aids in the formation of cancer spheroids. The spheroids are assessed after day 7 and 14 for the generation of reactive oxygen species (ROS), expression of the hypoxia inducing factor (HIF-1⍺) and vascular endothelial growth factor (VEGF). Production of ROS was observed due to the aggregated tumor mass, and enhanced production of HIF-1⍺ and VEGF results from a lack of oxygen and nutrition. Furthermore, the efficacy of anticancer drug doxorubicin at varying concentrations is assessed on ovarian cancer spheroids by studying the expression of caspase-3/7 at day 7 and 14. The current findings imply that the graphene-cellulose-alginate (GCA) scaffold generates a reliable ovarian cancer spheroid model to test the efficacy of the anticancer drug.

Targeting Conserved Pathways in 3D Spheroid Formation of Diverse Cell Types for Translational Application: Enhanced Functional and Antioxidant Capacity

Three-dimensional (3D) in vitro spheroid/organoid culture increasingly appears to better mimic physiological states than standard 2D systems. The biological consequence of 3D spheroids, however, differs for different cell types: for pluripotent embryonic stem cells (ESCs), differentiation and loss of stemness occur, while the converse is true for somatic and cancer cells. Despite such diverse consequences, there are likely conserved mechanisms governing 3D spheroid formation across cell types that are unknown but could be efficiently targeted for translational application. To elucidate such processes, we performed transcriptome analysis with functional validation on 2D- and 3D-cultured mouse ESCs, mesenchymal stromal/stem cells (MSCs), and cancer cells. At both the transcriptomic and functional levels, 3D spheroid formation resulted in commitment towards known cell-specific functional outcomes. Surprisingly in all cell types, downregulation of the cholesterol synthesis pathway was found during 3D spheroid formation, with modulation concomitantly affecting 3D spheroid formation and cell-specific consequences; similar results were seen with human cell types. Furthermore, improved antioxidant capacity after 3D spheroid formation across cell types was further enhanced with modulation of the pathway. These findings demonstrate the profound cell-specific consequences and the translational value of understanding conserved mechanisms across diverse cell types after 3D spheroid formation.