4F2 (CD98) heavy chain is associated covalently with an amino acid transporter and controls intracellular trafficking and membrane topology of 4F2 heterodimer

A monoclonal antibody recognizing CD98 on human embryonic stem cells shows anti-tumor activity in hepatocellular carcinoma xenografts

CD98, also known as SLC3A2, is a multifunctional cell surface molecule consisting of amino acid transporters. CD98 is ubiquitously expressed in many types of tissues, but expressed at higher levels in cancerous tissues than in normal tissues. CD98 is also upregulated in most hepatocellular carcinoma (HCC) patients; however, the function of CD98 in HCC cells has been little studied. In this study, we generated a panel of monoclonal antibodies (MAbs) against surface proteins on human embryonic stem cells (hESCs). NPB15, one of the MAbs, bound to hESCs and various cancer cells, including HCC cells and non-small cell lung carcinoma (NSCLC) cells, but not to peripheral blood mononuclear cells (PBMCs) and primary hepatocytes. Immunoprecipitation and mass spectrometry identified the target antigen of NPB15 as CD98. CD98 depletion decreased cell proliferation, clonogenic survival, and migration and induced apoptosis in HCC cells. In addition, CD98 depletion decreased the expression of cancer stem cell (CSC) markers in HCC cells. In tumorsphere cultures, the expression of CD98 interacting with NPB15 was significantly increased, as were known CSC markers. After cell sorting by NPB15, cells with high expression of CD98 (CD98-high) showed higher clonogenic survival than cells with low expression of CD98 (CD98-low) in HCC cells, suggesting CD98 as a potential CSC marker on HCC cells. The chimeric version of NPB15 was able to induce antibody-dependent cellular cytotoxicity (ADCC) against HCC cells in vitro. NPB15 injection showed antitumor activity in an HCC xenograft mouse model. The results suggest that NPB15 may be developed as a therapeutic antibody for HCC patients.

Metabolic cell death in cancer: ferroptosis, cuproptosis, disulfidptosis, and beyond

Cell death resistance represents a hallmark of cancer. Recent studies have identified metabolic cell death as unique forms of regulated cell death resulting from an imbalance in the cellular metabolism. This review discusses the mechanisms of metabolic cell death-ferroptosis, cuproptosis, disulfidptosis, lysozincrosis, and alkaliptosis-and explores their potential in cancer therapy. Our review underscores the complexity of the metabolic cell death pathways and offers insights into innovative therapeutic avenues for cancer treatment.

A LAT1-Like Amino Acid Transporter Regulates Neuronal Activity in the Drosophila Mushroom Bodies

The proper functioning of neural circuits that integrate sensory signals is essential for individual adaptation to an ever-changing environment. Many molecules can modulate neuronal activity, including neurotransmitters, receptors, and even amino acids. Here, we ask whether amino acid transporters expressed by neurons can influence neuronal activity. We found that minidiscs (mnd), which encodes a light chain of a heterodimeric amino acid transporter, is expressed in different cell types of the adult Drosophila brain: in mushroom body neurons (MBs) and in glial cells. Using live calcium imaging, we found that MND expressed in α/β MB neurons is essential for sensitivity to the L-amino acids: Leu, Ile, Asp, Glu, Lys, Thr, and Arg. We found that the Target Of Rapamycin (TOR) pathway but not the Glutamate Dehydrogenase (GDH) pathway is involved in the Leucine-dependent response of α/β MB neurons. This study strongly supports the key role of MND in regulating MB activity in response to amino acids.

The CRL3KCTD10 ubiquitin ligase-USP18 axis coordinately regulates cystine uptake and ferroptosis by modulating SLC7A11

SLC7A11 is a cystine transporter and ferroptosis inhibitor. How the stability of SLC7A11 is coordinately regulated in response to environmental cystine by which E3 ligase and deubiquitylase (DUB) remains elusive. Here, we report that neddylation inhibitor MLN4924 increases cystine uptake by causing SLC7A11 accumulation, via inactivating Cullin-RING ligase-3 (CRL-3). We identified KCTD10 as the substrate-recognizing subunit of CRL-3 for SLC7A11 ubiquitylation, and USP18 as SLC7A11 deubiquitylase. Upon cystine deprivation, the protein levels of KCTD10 or USP18 are decreased or increased, respectively, contributing to SLC7A11 accumulation. By destabilizing or stabilizing SLC7A11, KCTD10, or USP18 inversely regulates the cystine uptake and ferroptosis. Biologically, MLN4924 combination with SLC7A11 inhibitor Imidazole Ketone Erastin (IKE) enhanced suppression of tumor growth. In human breast tumor tissues, SLC7A11 levels were negatively or positively correlated with KCTD10 or USP18, respectively. Collectively, our study defines how SLC7A11 and ferroptosis is coordinately regulated by the CRL3KCTD10/E3-USP18/DUB axis, and provides a sound rationale of drug combination to enhance anticancer efficacy.

Comprehensive analysis of disulfidptosis-related genes reveals the effect of disulfidptosis in ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory condition of the intestinal tract. Various programmed cell death pathways in the intestinal mucosa are crucial to the pathogenesis of UC. Disulfidptosis, a recently identified form of programmed cell death, has not been extensively reported in the context of UC. This study evaluated the expression of disulfidptosis-related genes (DRGs) in UC through public databases and assessed disulfide accumulation in the intestinal mucosal tissues of UC patients and dextran sulfate sodium (DSS)-induced colitis mice via targeted metabolomics. We utilized various bioinformatics techniques to identify UC-specific disulfidptosis signature genes, analyze their potential functions, and investigate their association with immune cell infiltration in UC. The mRNA and protein expression levels of these signature genes were confirmed in the intestinal mucosa of DSS-induced colitis mice and UC patients. A total of 24 DRGs showed differential expression in UC. Our findings underscore the role of disulfide stress in UC. Four UC-related disulfidptosis signature genes-SLC7A11, LRPPRC, NDUFS1, and CD2AP-were identified. Their relationships with immune infiltration in UC were analyzed using CIBERSORT, and their expression levels were validated by quantitative real-time PCR and western blotting. This study provides further insights into their potential functions and explores their links to immune infiltration in UC. In summary, disulfidptosis, as a type of programmed cell death, may significantly influence the pathogenesis of UC by modulating the homeostasis of the intestinal mucosal barrier.

Pan-cancer analysis of disulfidptosis with potential implications in prognosis, immune microenvironment, and drug resistance in human cancer

To get a systematic assessment of disulfidptosis-related genes across human cancers and explore the predictive role of disulfidptosis in cancer drug sensitivity. We developed a score-level model to quantify the level of disulfidptosis in 33 human cancers using TCGA data. The mRNA expression and protein levels of disulfidptosis-related genes in human cancer cells and tissues were detected and retrieved from the Human Protein Atlas. Multiomics bioinformatic analyses were performed to evaluate disulfidptosis-related gene characteristics as well as the effect of disulfidptosis on the cancer immune microenvironment and drug resistance. Thirty cancers showed significantly different expression levels of disulfidptosis-related genes between normal and tumor samples. The mRNA expression and protein level of disulfidptosis-related genes were consistent with TCGA databases in lung cancer and hepatocellular carcinoma. We also found that altered levels of the disulfidptosis score expression were usually related to patient prognosis, and high expression of disulfidptosis-related genes was associated with drug resistance in different cancer types. Our study illustrates the characterization of disulfidptosis in multiple cancer types and highlights its potential value as a predictive biomarker of drug response, which can pave the way for further investigation of the prognostic and therapeutic potential of disulfidptosis.

The role of ferroptosis in acute kidney injury: mechanisms and potential therapeutic targets

Acute kidney injury (AKI) is one of the most common and severe clinical renal syndromes with high morbidity and mortality. Ferroptosis is a form of programmed cell death (PCD), is characterized by iron overload, reactive oxygen species accumulation, and lipid peroxidation. As ferroptosis has been increasingly studied in recent years, it is closely associated with the pathophysiological process of AKI and provides a target for the treatment of AKI. This review offers a comprehensive overview of the regulatory mechanisms of ferroptosis, summarizes its role in various AKI models, and explores its interaction with other forms of cell death, it also presents research on ferroptosis in AKI progression to other diseases. Additionally, the review highlights methods for detecting and assessing AKI through the lens of ferroptosis and describes potential inhibitors of ferroptosis for AKI treatment. Finally, the review presents a perspective on the future of clinical AKI treatment, aiming to stimulate further research on ferroptosis in AKI.

Disulfidptosis, A Novel Cell Death Pathway: Molecular Landscape and Therapeutic Implications

Programmed cell death is pivotal for several physiological processes, including immune defense. Further, it has been implicated in the pathogenesis of developmental disorders and the onset of numerous diseases. Multiple modes of programmed cell death, including apoptosis, pyroptosis, necroptosis, and ferroptosis, have been identified, each with their own unique characteristics and biological implications. In February 2023, Liu Xiaoguang and his team discovered "disulfidptosis," a novel pathway of programmed cell death. Their findings demonstrated that disulfidptosis is triggered in glucose-starved cells exhibiting high expression of a protein called SLC7A11. Furthermore, disulfidptosis is marked by a drastic imbalance in the NADPH/NADP+ ratio and the abnormal accumulation of disulfides like cystine. These changes ultimately lead to the destabilization of the F-actin network, causing cell death. Given that high SLC7A11 expression is a key feature of certain cancers, these findings indicate that disulfidptosis could serve as the basis of innovative anti-cancer therapies. Hence, this review delves into the discovery of disulfidptosis, its underlying molecular mechanisms and metabolic regulation, and its prospective applications in disease treatment.

Upregulation of ATF4 mediates the cellular adaptation to pharmacologic inhibition of amino acid transporter LAT1 in pancreatic ductal adenocarcinoma cells

L-type amino acid transporter 1 (LAT1) is recognized as a promising target for cancer therapy; however, the cellular adaptive response to its pharmacological inhibition remains largely unexplored. This study examined the adaptive response to LAT1 inhibition using nanvuranlat, a high-affinity LAT1 inhibitor. Proteomic analysis revealed the activation of a stress-induced transcription factor ATF4 following LAT1 inhibition, aligning with the known cellular responses to amino acid deprivation. This activation was linked to the GCN2-eIF2α pathway which regulates translation initiation. Our results show that ATF4 upregulation counteracts the suppressive effect of nanvuranlat on cell proliferation in pancreatic ductal adenocarcinoma cell lines, suggesting a role for ATF4 in cellular adaptation to LAT1 inhibition. Importantly, dual targeting of LAT1 and ATF4 exhibited more substantial anti-proliferative effects in vitro than individual treatments. This study underscores the potential of combining LAT1 and ATF4 inhibition as a therapeutic strategy in cancer treatment.

Disulfidptosis decoded: a journey through cell death mysteries, regulatory networks, disease paradigms and future directions

Cell death is an important part of the life cycle, serving as a foundation for both the orderly development and the maintenance of physiological equilibrium within organisms. This process is fundamental, as it eliminates senescent, impaired, or aberrant cells while also promoting tissue regeneration and immunological responses. A novel paradigm of programmed cell death, known as disulfidptosis, has recently emerged in the scientific circle. Disulfidptosis is defined as the accumulation of cystine by cancer cells with high expression of the solute carrier family 7 member 11 (SLC7A11) during glucose starvation. This accumulation causes extensive disulfide linkages between F-actins, resulting in their contraction and subsequent detachment from the cellular membrane, triggering cellular death. The RAC1-WRC axis is involved in this phenomenon. Disulfidptosis sparked growing interest due to its potential applications in a variety of pathologies, particularly oncology, neurodegenerative disorders, and metabolic anomalies. Nonetheless, the complexities of its regulatory pathways remain elusive, and its precise molecular targets have yet to be definitively identified. This manuscript aims to meticulously dissect the historical evolution, molecular underpinnings, regulatory frameworks, and potential implications of disulfidptosis in various disease contexts, illuminating its promise as a groundbreaking therapeutic pathway and target.

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.

Disulfidptosis: disulfide stress-induced cell death

The cystine transporter solute carrier family 7 member 11 (SLC7A11) (also known as xCT) promotes glutathione synthesis and counters oxidative stress-induced cell death, including ferroptosis, by importing cystine. Also, SLC7A11 plays a crucial role in tumor development. However, recent studies have uncovered an unexpected role of SLC7A11 in promoting disulfidptosis, a novel form of regulated cell death induced by disulfide stress. In this review, we examine the opposing roles of SLC7A11 in regulating redox homeostasis and cell survival/death, summarize current knowledge on disulfidptosis, and explore its potential in disease treatment. A deeper understanding of disulfidptosis will offer new insights into fundamental cellular homeostasis and facilitate the development of innovative therapies for disease treatment.

Active nanoparticle targeting of MUC5AC ameliorates therapeutic outcome in experimental colitis

Inflammatory bowel diseases (IBDs), which include Crohn's disease (CD) and ulcerative colitis (UC), are chronic inflammatory diseases of the gastrointestinal tract and are characterized by chronic recurrent ulceration of the bowels. Colon-targeted drug delivery systems (DDS) have received significant attention for their potential to treat IBD by improving the inflamed tissue selectivity. Herein, antiMUC5AC-decorated drug loaded nanoparticles (NP) are suggested for active epithelial targeting and selective adhesion to the inflamed tissue in experimental colitis. NPs conjugated with antiMUC5AC (anti-MUC5) were tested for their degree of bioadhesion with HT29-MTX cells by comparison with non-targeted BSA-NP conjugates. In vivo, the selectivity of bioadhesion and the influence of ligand density in bioadhesion efficiency as well as the therapeutic benefit for glucocorticoid loaded anti-MUC5-NP were studied in a murine colitis model. Quantitative adhesion analyses showed that anti-MUC5-conjugated NP exhibited a much higher binding and selectivity to inflamed tissue compared to PNA-, IgG1- and BSA-NP conjugates used as controls. This bioadhesion efficiency was found to be dependent on the ligand density, present at the NP surface. The binding specificity between anti-MUC5 ligand and inflamed tissues was confirmed by fluorescence imaging. Both anti-MUC5-NP and all other glucocorticoid containing formulations led to a significant mitigation of the experimental colitis, as became evident from the substantial reduction of myeloperoxidase activity and pro-inflammatory cytokine concentrations (TNF-α, IL-1β). Targeted NP by using anti-MUC5 appears to be a very promising tool in future treatment of various types of local disorders affecting the gastro-intestinal tract but not limited to colitis.

NINJ1 regulates ferroptosis via xCT antiporter interaction and CoA modulation

Ninjurin-1 (NINJ1), initially identified as a stress-induced protein in neurons, recently emerged as a key mediator of plasma membrane rupture during apoptosis, necrosis, and pyroptosis. However, its involvement in ferroptosis remains unknown. Here, we demonstrate that NINJ1 also plays a crucial role in ferroptosis, but through a distinct mechanism. NINJ1 knockdown significantly protected cancer cells against ferroptosis induced by xCT inhibitors but no other classes of ferroptosis-inducing compounds (FINs). Glycine, known to inhibit canonical NINJ1-mediated membrane rupture in other cell deaths, had no impact on ferroptosis. A compound screen revealed that NINJ1-mediated ferroptosis protection can be abolished by pantothenate kinase inhibitor (PANKi), buthionine sulfoximine (BSO), and diethylmaleate (DEM). These results suggest that this ferroptosis protection is mediated via Coenzyme A (CoA) and glutathione (GSH), both of which were found to be elevated upon NINJ1 knockdown. Furthermore, we discovered that NINJ1 interacts with the xCT antiporter, which is responsible for cystine uptake for the biosynthesis of CoA and GSH. The removal of NINJ1 increased xCT levels and stability, enhanced cystine uptake, and contributed to elevated CoA and GSH levels, collectively contributing to ferroptosis protection. These findings reveal that NINJ1 regulates ferroptosis via a non-canonical mechanism, distinct from other regulated cell deaths.

FBW7/GSK3β mediated degradation of IGF2BP2 inhibits IGF2BP2-SLC7A5 positive feedback loop and radioresistance in lung cancer

BACKGROUND

The development of radioresistance seriously hinders the efficacy of radiotherapy in lung cancer. However, the underlying mechanisms by which radioresistance occurs are still incompletely understood. The N6-Methyladenosine (m6A) modification of RNA is involved in cancer progression, but its role in lung cancer radioresistance remains elusive. This study aimed to identify m6A regulators involved in lung cancer radiosensitivity and further explore the underlying mechanisms to identify therapeutic targets to overcome lung cancer radioresistance.

METHODS

Bioinformatic mining was used to identify the m6A regulator IGF2BP2 involved in lung cancer radiosensitivity. Transcriptome sequencing was used to explore the downstream factors. Clonogenic survival assays, neutral comet assays, Rad51 foci formation assays, and Annexin V/propidium iodide assays were used to determine the significance of FBW7/IGF2BP2/SLC7A5 axis in lung cancer radioresistance. Chromatin immunoprecipitation (ChIP)-qPCR analyses, RNA immunoprecipitation (RIP) and methylated RNA immunoprecipitation (MeRIP)-qPCR analyses, RNA pull-down analyses, co-immunoprecipitation analyses, and ubiquitination assays were used to determine the feedback loop between IGF2BP2 and SLC7A5 and the regulatory effect of FBW7/GSK3β on IGF2BP2. Mice models and tissue microarrays were used to verify the effects in vivo.

RESULTS

We identified IGF2BP2, an m6A "reader", that is overexpressed in lung cancer and facilitates radioresistance. We showed that inhibition of IGF2BP2 impairs radioresistance in lung cancer both in vitro and in vivo. Furthermore, we found that IGF2BP2 enhances the stability and translation of SLC7A5 mRNA through m6A modification, resulting in enhanced SLC7A5-mediated transport of methionine to produce S-adenosylmethionine. This feeds back upon the IGF2BP2 promoter region by further increasing the trimethyl modification at lysine 4 of histone H3 (H3K4me3) level to upregulate IGF2BP2 expression. We demonstrated that this positive feedback loop between IGF2BP2 and SLC7A5 promotes lung cancer radioresistance through the AKT/mTOR pathway. Moreover, we found that the ubiquitin ligase FBW7 functions with GSK3β kinase to recognize and degrade IGF2BP2.

CONCLUSIONS

Collectively, our study revealed that the m6A "reader" IGF2BP2 promotes lung cancer radioresistance by forming a positive feedback loop with SLC7A5, suggesting that IGF2BP2 may be a potential therapeutic target to control radioresistance in lung cancer.

Ferroptosis: a dual-edged sword in tumour growth

Ferroptosis, a recently identified form of non-apoptotic cell death, is distinguished by its dependence on iron-triggered lipid peroxidation and accumulation of iron. It has been linked to various disorders, including the development of tumours. Interestingly, ferroptosis appears to exhibit a dual role in the context of tumour growth. This article provides a thorough exploration of the inherent ambivalence within ferroptosis, encompassing both its facilitation and inhibition of tumorous proliferation. It examines potential therapeutic targets associated with ferroptosis, the susceptibility of cancerous cells to ferroptosis, strategies to enhance the efficacy of existing cancer treatments, the interaction between ferroptosis and the immune response to tumours, and the fundamental mechanisms governing ferroptosis-induced tumour progression. A comprehensive understanding of how ferroptosis contributes to tumour biology and the strategic management of its dual nature are crucial for maximizing its therapeutic potential.

Ferroptosis: potential targets and emerging roles in pancreatic diseases

Ferroptosis is a newly discovered form of regulatory cell death characterized by excessive iron-dependent lipid peroxidation. In the past decade, significant breakthroughs have been made in comprehending the features and regulatory mechanisms of ferroptosis, and it has been confirmed that ferroptosis plays a pivotal role in the pathophysiological processes of various diseases, including tumors, inflammation, neurodegenerative diseases, and infectious diseases. The pancreas, which is the second largest digestive gland in the human body and has both endocrine and exocrine functions, is a vital organ for controlling digestion and metabolism. In recent years, numerous studies have confirmed that ferroptosis is closely related to pancreatic diseases, which is attributed to abnormal iron accumulation, as an essential biochemical feature of ferroptosis, is often present in the pathological processes of various pancreatic exocrine and endocrine diseases and the vulnerability of the pancreas to oxidative stress stimulation and damage. Therefore, comprehending the regulatory mechanism of ferroptosis in pancreatic diseases may provide valuable new insights into treatment strategies. In this review, we first summarize the hallmark features of ferroptosis and then analyze the exact mechanisms by which ferroptosis is precisely regulated at multiple levels and links, including iron metabolism, lipid metabolism, the GPX4-mediated ferroptosis defense system, the GPX4-independent ferroptosis defense system, and the regulation of autophagy on ferroptosis. Finally, we discuss the role of ferroptosis in the occurrence and development of pancreatic diseases and summarize the feasibility and limitations of ferroptosis as a therapeutic target for pancreatic diseases.

Targeting ferroptosis in gastric cancer: Strategies and opportunities

Ferroptosis is a novel form of programmed cell death morphologically, genetically, and biochemically distinct from other cell death pathways and characterized by the accumulation of iron-dependent lipid peroxides and oxidative damage. It is now understood that ferroptosis plays an essential role in various biological processes, especially in the metabolism of iron, lipids, and amino acids. Gastric cancer (GC) is a prevalent malignant tumor worldwide with low early diagnosis rates and high metastasis rates, accounting for its relatively poor prognosis. Although chemotherapy is commonly used to treat GC, drug resistance often leads to poor therapeutic outcomes. In the last several years, extensive research on ferroptosis has highlighted its significant potential in GC therapy, providing a promising strategy to address drug resistance associated with standard cancer therapies. In this review, we offer an extensive summary of the key regulatory factors related to the mechanisms underlying ferroptosis. Various inducers and inhibitors specifically targeting ferroptosis are uncovered. Additionally, we explore the prospective applications and outcomes of these agents in the field of GC therapy, emphasizing their capacity to improve the outcomes of this patient population.

Slc7a11 stimulates glutathione synthesis to preserve fatty acid metabolism in primary hepatocytes

Primary hepatocytes are widely used as a tool for studying metabolic function and regulation in the liver. However, the metabolic properties of primary hepatocytes are gradually lost after isolation. Here, we illustrated that fatty acid metabolism is the major compromised metabolic process in isolated primary hepatocytes, along with drastically decreased GSH and ROS content, while lipid peroxidation is increased. Gain- and loss-of-function studies revealed that Slc7a11 expression is critical in maintaining fatty acid metabolism and facilitating hormone-induced fatty acid metabolic events, which is synergistic with dexamethasone treatment. Intriguingly, Slc7a11 expression and dexamethasone treatment cooperatively upregulated AKT and AMPK signaling and mitochondrial complex expression in primary hepatocytes. Furthermore, direct treatment with reduced GSH or inhibition of ferroptosis is sufficient to drive protective effects on fatty acid metabolism in primary hepatocytes. Our results demonstrate that Slc7a11 expression in isolated primary hepatocytes induces GSH production, which protects against ferroptosis, to increase fatty acid metabolic gene expression, AKT and AMPK signaling and mitochondrial function in synergy with dexamethasone treatment, thereby efficiently preserving primary hepatocyte metabolic signatures, thus providing a promising approach to better reserve primary hepatocyte metabolic activities after isolation to potentially improve the understanding of liver biological functions from studies using primary hepatocytes.

Universal method for the isolation of microvessels from frozen brain tissue: A proof-of-concept multiomic investigation of the neurovasculature

The neurovascular unit, comprised of vascular cell types that collectively regulate cerebral blood flow to meet the needs of coupled neurons, is paramount for the proper function of the central nervous system. The neurovascular unit gatekeeps blood-brain barrier properties, which experiences impairment in several central nervous system diseases associated with neuroinflammation and contributes to pathogenesis. To better understand function and dysfunction at the neurovascular unit and how it may confer inflammatory processes within the brain, isolation and characterization of the neurovascular unit is needed. Here, we describe a singular, standardized protocol to enrich and isolate microvessels from archived snap-frozen human and frozen mouse cerebral cortex using mechanical homogenization and centrifugation-separation that preserves the structural integrity and multicellular composition of microvessel fragments. For the first time, microvessels are isolated from postmortem ventromedial prefrontal cortex tissue and are comprehensively investigated as a structural unit using both RNA sequencing and Liquid Chromatography with tandem mass spectrometry (LC-MS/MS). Both the transcriptome and proteome are obtained and compared, demonstrating that the isolated brain microvessel is a robust model for the NVU and can be used to generate highly informative datasets in both physiological and disease contexts.

mTORC2-AKT-LAT1 signalling participates in methionine-induced β-CASEIN expression in mammary epithelial cells of dairy cows

This study investigated the role of the mammalian target of rapamycin complex 2 (mTORC2)-protein kinase B (AKT) signalling in methionine (Met)-induced L-type amino acid transporter 1 (LAT1) expression and milk protein production. Primary mammary epithelial cells (MECs) from mammary parenchymal tissues of three lactating cows and MAC-T bovine MECs were cultured with or without 0.6 mM Met. Rapamycin-insensitive companion of mTOR (RICTOR) siRNA, the mTORC1 inhibitor rapamycin and the AKT activator SC79 were used to evaluate the effects of mTORC2-AKT signalling on Met-induced LAT1 expression and function. Each experiment was performed three times. Data were analysed with a two-sided unpaired t test or ANOVA with the Bonferroni multiple-comparison test. Western blotting showed that Met stimulation increased RICTOR expression (~244.67%; p < 0.05; control, 0.15 ± 0.026; Met, 0.517 ± 0.109) and AKT-S473 levels (~281.42%; p < 0.01; control, 0.253 ± 0.067; Met, 0.965 ± 0.019) in both primary MECs and MAC-T cells. Rapamycin-induced mTORC1 signalling inhibition decreased only Met-induced β-CASEIN expression by ~21.24% (p < 0.01; Met, 0.777 ± 0.01; Met and rapamycin, 0.612 ± 0.04) and did not affect Met-stimulated AKT-S473 levels, suggesting that mTORC2-AKT activation upon Met stimulation also contributes to milk protein synthesis. LAT1 participates in Met-induced β-CASEIN expression. In dairy cow MECs, mTORC2 inhibition by RICTOR siRNA decreased LAT1 levels on the plasma membrane by ~45.13% (p < 0.01; control, 0.359 ± 0.006; siRICTOR, 0.197 ± 0.004). However, SC79-induced AKT activation had the opposite effect (p < 0.01). In primary MECs and MAC-T cells, Met stimulation increased cytosolic and plasma membrane LAT1 expression respectively (MECs, 113.98% and 58.43%; MAC-T, 165.85% and 396.39%; p < 0.05). However, RICTOR siRNA significantly reduced Met-induced plasma membrane LAT1 expression (~76.48%; Met, 0.539 ± 0.05; Met and siRICTOR, 0.127 ± 0.012; p < 0.05). Thus, Met increased LAT1 expression and function via mTORC2-AKT signalling, upregulating milk protein synthesis in dairy cow MECs.

Research on ferroptosis as a therapeutic target for the treatment of neurodegenerative diseases

Ferroptosis is an iron- and lipid peroxidation (LPO)-mediated programmed cell death type. Recently, mounting evidence has indicated the involvement of ferroptosis in neurodegenerative diseases, especially in Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), Huntington's disease (HD), and so on. Treating ferroptosis presents opportunities as well as challenges for neurodegenerative diseases. This review provides a comprehensive overview of typical features of ferroptosis and the underlying mechanisms that contribute to its occurrence, as well as their implications in the pathogenesis and advancement of major neurodegenerative disorders. Meanwhile, we summarize the utilization of ferroptosis inhibition in both experimental and clinical approaches for the treatment of major neurodegenerative disorders. In addition, we specifically summarize recent advances in developing therapeutic means targeting ferroptosis in these diseases, which may guide future approaches for the effective management of these devastating medical conditions.

The human LAT1-4F2hc (SLC7A5-SLC3A2) transporter complex: Physiological and pathophysiological implications

LAT1 and 4F2hc form a heterodimeric membrane protein complex, which functions as one of the best characterized amino acid transporters. Since LAT1-4F2hc is required for the efficient uptake of essential amino acids and hormones, it promotes cellular growth, in part, by stimulating mTORC1 (mechanistic target of rapamycin complex 1) signalling and by repressing the integrated stress response (ISR). Gain or loss of LAT1-4F2hc function is associated with cancer, diabetes, and immunological and neurological diseases. Hence, LAT1-4F2hc represents an attractive drug target for disease treatment. Specific targeting of LAT1-4F2hc will be facilitated by the increasingly detailed understanding of its molecular architecture, which provides important concepts for its function and regulation. Here, we summarize (i) structural insights that help to explain how LAT1 and 4F2hc assemble to transport amino acids across membranes, (ii) the role of LAT1-4F2hc in key metabolic signalling pathways, and (iii) how derailing these processes could contribute to diseases.

Mechanisms and regulations of ferroptosis

Regulation of cell mortality for disease treatment has been the focus of research. Ferroptosis is an iron-dependent regulated cell death whose mechanism has been extensively studied since its discovery. A large number of studies have shown that regulation of ferroptosis brings new strategies for the treatment of various benign and malignant diseases. Iron excess and lipid peroxidation are its primary metabolic features. Therefore, genes involved in iron metabolism and lipid metabolism can regulate iron overload and lipid peroxidation through direct or indirect pathways, thereby regulating ferroptosis. In addition, glutathione (GSH) is the body's primary non-enzymatic antioxidants and plays a pivotal role in the struggle against lipid peroxidation. GSH functions as an auxiliary substance for glutathione peroxidase 4 (GPX4) to convert toxic lipid peroxides to their corresponding alcohols. Here, we reviewed the researches on the mechanism of ferroptosis in recent years, and comprehensively analyzed the mechanism and regulatory process of ferroptosis from iron metabolism and lipid metabolism, and then described in detail the metabolism of GPX4 and the main non-enzymatic antioxidant GSH in vivo.

CD98 heavy chain as a prognostic biomarker and target for cancer treatment

The SLC3A2 gene encodes for a cell-surface transmembrane protein CD98hc (4F2). CD98hc serves as a chaperone for LAT1 (SLC7A5), LAT2 (SLC7A8), y+LAT1 (SLC7A7), y+LAT2 (SLC7A6), xCT (SLC7A11) and Asc1 (SLC7A10) providing their recruitment to the plasma membrane. Together with the light subunits, it constitutes heterodimeric transmembrane amino acid transporters. CD98hc interacts with other surface molecules, such as extracellular matrix metalloproteinase inducer CD147 (EMMPRIN) and adhesion receptors integrins, and regulates glucose uptake. In this way, CD98hc connects the signaling pathways sustaining cell proliferation and migration, biosynthesis and antioxidant defense, energy production, and stem cell properties. This multifaceted role makes CD98hc one of the critical regulators of tumor growth, therapy resistance, and metastases. Indeed, the high expression levels of CD98hc were confirmed in various tumor tissues, including head and neck squamous cell carcinoma, glioblastoma, colon adenocarcinoma, pancreatic ductal adenocarcinoma, and others. A high expression of CD98hc has been linked to clinical prognosis and response to chemo- and radiotherapy in several types of cancer. In this mini-review, we discuss the physiological functions of CD98hc, its role in regulating tumor stemness, metastases, and therapy resistance, and the clinical significance of CD98hc as a tumor marker and therapeutic target.

CD98hc is a target for brain delivery of biotherapeutics

Brain exposure of systemically administered biotherapeutics is highly restricted by the blood-brain barrier (BBB). Here, we report the engineering and characterization of a BBB transport vehicle targeting the CD98 heavy chain (CD98hc or SLC3A2) of heterodimeric amino acid transporters (TVCD98hc). The pharmacokinetic and biodistribution properties of a CD98hc antibody transport vehicle (ATVCD98hc) are assessed in humanized CD98hc knock-in mice and cynomolgus monkeys. Compared to most existing BBB platforms targeting the transferrin receptor, peripherally administered ATVCD98hc demonstrates differentiated brain delivery with markedly slower and more prolonged kinetic properties. Specific biodistribution profiles within the brain parenchyma can be modulated by introducing Fc mutations on ATVCD98hc that impact FcγR engagement, changing the valency of CD98hc binding, and by altering the extent of target engagement with Fabs. Our study establishes TVCD98hc as a modular brain delivery platform with favorable kinetic, biodistribution, and safety properties distinct from previously reported BBB platforms.

An amino acid transporter subunit as an antibody-drug conjugate target in colorectal cancer

BACKGROUND

Advanced colorectal cancer (CRC) is difficult to treat. For that reason, the development of novel therapeutics is necessary. Here we describe a potentially actionable plasma membrane target, the amino acid transporter protein subunit CD98hc.

METHODS

Western blot and immunohistochemical analyses of CD98hc protein expression were carried out on paired normal and tumoral tissues from patients with CRC. Immunofluorescence and western studies were used to characterize the action of a DM1-based CD98hc-directed antibody-drug conjugate (ADC). MTT and Annexin V studies were performed to evaluate the effect of the anti-CD98hc-ADC on cell proliferation and apoptosis. CRISPR/Cas9 and shRNA were used to explore the specificity of the ADC. In vitro analyses of the antitumoral activity of the anti-CD98hc-ADC on 3D patient-derived normal as well as tumoral organoids were also carried out. Xenografted CRC cells and a PDX were used to analyze the antitumoral properties of the anti-CD98hc-ADC.

RESULTS

Genomic as well proteomic analyses of paired normal and tumoral samples showed that CD98hc expression was significantly higher in tumoral tissues as compared to levels of CD98hc present in the normal colonic tissue. In human CRC cell lines, an ADC that recognized the CD98hc ectodomain, reached the lysosomes and exerted potent antitumoral activity. The specificity of the CD98hc-directed ADC was demonstrated using CRC cells in which CD98hc was decreased by shRNA or deleted using CRISPR/Cas9. Studies in patient-derived organoids verified the antitumoral action of the anti-CD98hc-ADC, which largely spared normal tissue-derived colon organoids. In vivo studies using xenografted CRC cells or patient-derived xenografts confirmed the antitumoral activity of the anti-CD98hc-ADC.

CONCLUSIONS

The studies herewith reported indicate that CD98hc may represent a novel ADC target that, upon well-designed clinical trials, could be used to increase the therapeutic armamentarium against CRC.

Targeting N-glycosylation of 4F2hc mediated by glycosyltransferase B3GNT3 sensitizes ferroptosis of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains a highly fatal malignancy partially due to the acquired alterations related to aberrant protein glycosylation that pathologically remodel molecular biological processes and protect PDAC cells from death. Ferroptosis driven by lethal lipid peroxidation provides a targetable vulnerability for PDAC. However, the crosstalk between glycosylation and ferroptosis remains unclear. Here, we identified 4F2hc, a subunit of the glutamate-cystine antiporter system Xc-, and its asparagine (N)-glycosylation is involved in PDAC ferroptosis by N- and O-linked glycoproteomics. Knockdown of SLC3A2 (gene name of 4F2hc) or blocking the N-glycosylation of 4F2hc potentiates ferroptosis sensitization of PDAC cells by impairing the activity of system Xc- manifested by a marked decrease in intracellular glutathione. Mechanistically, we found that the glycosyltransferase B3GNT3 catalyzes the glycosylation of 4F2hc, stabilizes the 4F2hc protein, and enhances the interaction between 4F2hc and xCT. Knockout of B3GNT3 or deletion of enzymatically active B3GNT3 sensitizes PDAC cells to ferroptosis. Reconstitution of 4F2hc-deficient cells with wildtype 4F2hc restores ferroptosis resistance while glycosylation-mutated 4F2hc does not. Additionally, upon combination with a ferroptosis inducer, treatment with the classical N-glycosylation inhibitor tunicamycin (TM) markedly triggers the overactivation of lipid peroxidation and enhances the sensitivity of PDAC cells to ferroptosis. Notably, we confirmed that genetic perturbation of SLC3A2 or combination treatment with TM significantly augments ferroptosis-induced inhibition of orthotopic PDAC. Clinically, high expression of 4F2hc and B3GNT3 contributes to the progression and poor survival of PDAC patients. Collectively, our findings reveal a previously unappreciated function of N-glycosylation of 4F2hc in ferroptosis and suggest that dual targeting the vulnerabilities of N-glycosylation and ferroptosis may be an innovative therapeutic strategy for PDAC.

The role of ferroptosis in intervertebral disc degeneration

Nucleus pulposus, annulus fibrosus, and cartilage endplate constitute an avascular intervertebral disc (IVD), which is crucial for spinal and intervertebral joint mobility. As one of the most widespread health issues worldwide, intervertebral disc degeneration (IVDD) is recognized as a key contributor to back and neck discomfort. A number of degenerative disorders have a strong correlation with ferroptosis, a recently identified novel regulated cell death (RCD) characterized by an iron-dependent mechanism and a buildup of lipid reactive oxygen species (ROS). There is growing interest in the part ferroptosis plays in IVDD pathophysiology. Inhibiting ferroptosis has been shown to control IVDD development. Several studies have demonstrated that in TBHP-induced oxidative stress models, changes in ferroptosis marker protein levels and increased lipid peroxidation lead to the degeneration of intervertebral disc cells, which subsequently aggravates IVDD. Similarly, IVDD is significantly relieved with the use of ferroptosis inhibitors. The purpose of this review was threefold: 1) to discuss the occurrence of ferroptosis in IVDD; 2) to understand the mechanism of ferroptosis and its role in IVDD pathophysiology; and 3) to investigate the feasibility and prospect of ferroptosis in IVDD treatment.

The role of regulated necrosis in inflammation and ocular surface diseases

In recent decades, numerous types of regulated cell death have been identified, including pyroptosis, ferroptosis and necroptosis. Regulated necrosis is characterized by a series of amplified inflammatory responses that result in cell death. Therefore, it has been suggested to play an essential role in the pathogenesis of ocular surface diseases. The cell morphological features and molecular mechanisms of regulated necrosis are discussed in this review. Furthermore, it summarizes the role of ocular surface diseases, such as dry eye, keratitis, and cornea alkali burn, as potential disease prevention and treatment targets.

AKT activation because of PTEN loss upregulates xCT via GSK3β/NRF2, leading to inhibition of ferroptosis in PTEN-mutant tumor cells

Here, we show that the tumor suppressor phosphatase and tensin homolog deleted from chromosome 10 (PTEN) sensitizes cells to ferroptosis, an iron-dependent form of cell death, by restraining the expression and activity of the cystine/glutamate antiporter system Xc- (xCT). Loss of PTEN activates AKT kinase to inhibit GSK3β, increasing NF-E2 p45-related factor 2 (NRF2) along with transcription of one of its known target genes encoding xCT. Elevated xCT in Pten-null mouse embryonic fibroblasts increases the flux of cystine transport and synthesis of glutathione, which enhances the steady-state levels of these metabolites. A pan-cancer analysis finds that loss of PTEN shows evidence of increased xCT, and PTEN-mutant cells are resistant to ferroptosis as a consequence of elevated xCT. These findings suggest that selection of PTEN mutation during tumor development may be due to its ability to confer resistance to ferroptosis in the setting of metabolic and oxidative stress that occurs during tumor initiation and progression.

LAT1 enables T cell activation under inflammatory conditions

The aim of this study was to assess the L-type amino acid transporter-1 (LAT1) as a possible therapeutic target for rheumatoid arthritis (RA). Synovial LAT1 expression in RA was monitored by immunohistochemistry and transcriptomic datasets. The contribution of LAT1 to gene expression and immune synapse formation was assessed by RNA-sequencing and total internal reflection fluorescent (TIRF) microscopy, respectively. Mouse models of RA were used to assess the impact of therapeutic targeting of LAT1. LAT1 was strongly expressed by CD4⁺ T cells in the synovial membrane of people with active RA and the level of expression correlated with levels of ESR and CRP as well as DAS-28 scores. Deletion of LAT1 in murine CD4⁺ T cells inhibited the development of experimental arthritis and prevented the differentiation of CD4⁺ T cells expressing IFN-γ and TNF-α, without affecting regulatory T cells. LAT1 deficient CD4⁺ T cells demonstrated reduced transcription of genes associated with TCR/CD28 signalling, including Akt1, Akt2, Nfatc2, Nfkb1 and Nfkb2. Functional studies using TIRF microscopy revealed a significant impairment of immune synapse formation with reduced recruitment of CD3ζ and phospho-tyrosine signalling molecules in LAT1 deficient CD4⁺ T cells from the inflamed joints but not the draining lymph nodes of arthritic mice. Finally, it was shown that a small molecule LAT1 inhibitor, currently undergoing clinical trials in man, was highly effective in treating experimental arthritis in mice. It was concluded that LAT1 plays a critical role in activation of pathogenic T cell subsets under inflammatory conditions and represents a promising new therapeutic target for RA.

Ferroptosis landscape in prostate cancer from molecular and metabolic perspective

Prostate cancer is a major disease that threatens men's health. Its rapid progression, easy metastasis, and late castration resistance have brought obstacles to treatment. It is necessary to find new effective anticancer methods. Ferroptosis is a novel iron-dependent programmed cell death that plays a role in various cancers. Understanding how ferroptosis is regulated in prostate cancer will help us to use it as a new way to kill cancer cells. In this review, we summarize the regulation and role of ferroptosis in prostate cancer and the relationship with AR from the perspective of metabolism and molecular pathways. We also discuss the feasibility of ferroptosis in prostate cancer treatment and describe current limitations and prospects, providing a reference for future research and clinical application of ferroptosis.

Ferroptosis and Neurodegenerative Diseases: Insights into the Regulatory Roles of SLC7A11

Programed cell death plays a key role in promoting human development and maintaining homeostasis. Ferroptosis is a recently identified pattern of programmed cell death that is closely associated with the onset and progression of neurodegenerative diseases. Ferroptosis is mainly caused by the intracellular accumulation of iron-dependent lipid peroxides. The cysteine/glutamate antibody Solute carrier family 7 member 11 (SLC7A11, also known as xCT) functions to import cysteine for glutathione biosynthesis and antioxidant defense. SLC7A11 has a significant impact on ferroptosis, and inhibition of SLC7A11 expression promotes ferroptosis. Moreover, SLC7A11 is also closely associated with neurodegenerative diseases. In this paper, we summarize the relationship between ferroptosis and neurodegenerative diseases and the role of SLC7A11 during this process. The various regulatory mechanisms of SLC7A11 are also discussed. In conclusion, we are looking forward to a theoretical basis for further understanding the occurrence and development of ferroptosis in SLC7A11 and neurodegenerative diseases, and to seek new clues for the treatment of neurodegenerative diseases.

Contribution of the L-Type Amino Acid Transporter Family in the Diagnosis and Treatment of Prostate Cancer

The L-type amino acid transporter (LAT) family contains four members, LAT1~4, which are important amino acid transporters. They mainly transport specific amino acids through cell membranes, provide nutrients to cells, and are involved in a variety of metabolic pathways. They regulate the mTOR signaling pathway which has been found to be strongly linked to cancer in recent years. However, in the field of prostate cancer (PCa), the LAT family is still in the nascent stage of research, and the importance of LATs in the diagnosis and treatment of prostate cancer is still unknown. Therefore, this article aims to report the role of LATs in prostate cancer and their clinical significance and application. LATs promote the progression of prostate cancer by increasing amino acid uptake, activating the mammalian target of rapamycin (mTOR) pathway and downstream signals, mediating castration-resistance, promoting tumor angiogenesis, and enhancing chemotherapy resistance. The importance of LATs as diagnostic and therapeutic targets for prostate cancer was emphasized and the latest research results were introduced. In addition, we introduced selective LAT1 inhibitors, including JPH203 and OKY034, which showed excellent inhibitory effects on the proliferation of various tumor cells. This is the future direction of amino acid transporter targeting therapy drugs.

The early faecal microbiota transfer alters bile acid circulation and amino acid transport of the small intestine in piglets

The purpose of this study was to investigate the effects of faecal microbiota transfer (FMT) with lactation Min sows as faecal donor on blood immunity, small intestine amino acid transport capacity, bile acid circulation, and colon microbiota of recipient piglets. From Days 1 to 10, the recipient group (R group) was orally inoculated with a faecal suspension. The control group (Con group) was orally inoculated with sterile physiological saline. On Day 21, the results showed that the immunoglobulin A (IgA) concentration in plasma of the R group was increased (p < 0.05). The expression of 4F2hc in the jejunal mucosa and ileum mucosa of the R group was ameliorated (p < 0.05). The relative abundance of Synergistetes in the colon of the R group was increased, Proteobacteria was diminished by FMT (p < 0.05). On Day 40, the concentrations of IgA, IgG, and interleukin-2 detected in the plasma of the R group were increased (p < 0.05). FXR and fibroblast growth factor 19 gene expression was upregulated in ileum mucosa, CYP7A1 and Na⁺ taurocholate cotransporter polypeptide gene expression were downregulated in the liver and organic solute transporters α/β was downregulated in colonic mucosa (p < 0.05). The relative abundance of Proteobacteria and Spirochaetes in the colon of the R group was decreased (p < 0.05). In conclusion, an early FMT with lactation Min sows as faecal donors can alter the small intestine amino acid transport capacity, bile acid circulation, and colonic microbiota of recipient piglets during lactation and after weaning.

Kidney tubular epithelial cell ferroptosis links glomerular injury to tubulointerstitial pathology in lupus nephritis

Ferroptosis is a druggable, iron-dependent form of cell death that is characterized by lipid peroxidation but has received little attention in lupus nephritis. Kidneys of lupus nephritis patients and mice showed increased lipid peroxidation mainly in the tubular segments and an increase in Acyl-CoA synthetase long-chain family member 4, a pro-ferroptosis enzyme. Nephritic mice had an attenuated expression of SLC7A11, a cystine importer, an impaired glutathione synthesis pathway, and low expression of glutathione peroxidase 4, a ferroptosis inhibitor. Lipidomics of nephritic kidneys confirmed ferroptosis. Using nephrotoxic serum, we induced immune complex glomerulonephritis in congenic mice and demonstrate that impaired iron sequestration within the proximal tubules exacerbates ferroptosis. Lupus nephritis patient serum rendered human proximal tubular cells susceptibility to ferroptosis which was inhibited by Liproxstatin-2, a novel ferroptosis inhibitor. Collectively, our findings identify intra-renal ferroptosis as a pathological feature and contributor to tubular injury in human and murine lupus nephritis.

Amino acid profiles, amino acid sensors and transporters expression and intestinal microbiota are differentially altered in goats infected with Haemonchus contortus

Infection with the nematode Haemonchus contortus causes host malnutrition and gastrointestinal injuries. The objective of this study was to investigate the effects of H. contortus infection on gastrointestinal contents of free amino acids (AA), the expression of AA transporters and microbiota with a focus on amino acid metabolism. Twenty-four Xiangdong black goats (13 ± 1.5 kg, 6 months old) were randomly assigned into the control group (n = 8) and the infected group (n = 16). The results showed that H. contortus infection increased (P < 0.05) the free AA contents in jejunum and ileum digesta. The concentrations of blood threonine, phenylalanine and tyrosine were lower (P < 0.05) in the infected group as compared to the control group. In the jejunum and ileum epithelium, H. contortus infection significantly (P < 0.05) down-regulated the expression of AA transporter b^0,+AT/rBAT and B0AT1, but up-regulated (P < 0.05) the expression of transporter CAT2 and xCT. Furthermore, microbiota in both jejunum (Bifidobacteriaceae, Lachnospiraceae, Bacteroidaceae, Enterobacteriaceae, and Micrococcaceae) and ileum (Acidaminococcaceae, Desulfovibrionaceae, Bacteroidaceae, and Peptostreptococcaceae) were also altered at the family level by H. contortus infection. The  commensal bacteria of jejunum showed a close correlation with amino acids, AA transporters, and amino acid metabolism, especially cystine. In conclusion, H. contortus infection affected the intestinal AA contents and the expression of intestinal AA transporters, suggesting altered AA metabolism and absorption, which were accompanied by changes in the relative abundances of gut bacteria that mediate amino acid metabolism.

Drug library screening identifies histone deacetylase inhibition as a novel therapeutic strategy for choriocarcinoma

BACKGROUND

Choriocarcinoma is a rare and aggressive gynecological malignancy. The standard treatment is systemic chemotherapy as choriocarcinoma exhibits high chemosensitivity. However, refractory choriocarcinoma exhibits chemoresistance; thus, the prognosis remains very poor. This study aimed to identify novel therapeutic agents for choriocarcinoma by utilizing a drug repositioning strategy.

METHODS

Three choriocarcinoma cell lines (JAR, JEG-3, and BeWo) and a human extravillous trophoblast cell line (HTR-8/SVneo) were used for the analyses. The growth inhibitory effects of 1,271 FDA-approved compounds were evaluated in vitro screening assays and selected drugs were tested in tumor-bearing mice. Functional analyses of drug effects were performed based on RNA sequencing.

RESULTS

Muti-step screening identified vorinostat, camptothecin (S, +), topotecan, proscillaridin A, and digoxin as exhibiting an anti-cancer effect in choriocarcinoma cells. Vorinostat, a histone deacetylase inhibitor, was selected as a promising candidate for validation and the IC50 values for choriocarcinoma cells were approximately 1 μM. RNA sequencing and subsequent pathway analysis revealed that the ferroptosis pathway was likely implicated, and key ferroptosis-related genes (i.e., GPX4, NRF2, and SLC3A2) were downregulated following vorinostat treatment. Furthermore, vorinostat repressed tumor growth and downregulated the expression of GPX4 and NRF2 in JAR cell-bearing mice model.

CONCLUSION

Vorinostat, a clinically approved drug for the treatment of advanced primary cutaneous T-cell lymphoma, showed a remarkable anticancer effect both in vitro and in vivo by regulating the expression of ferroptosis-related genes. Therefore, vorinostat may be an effective therapeutic candidate for patients with choriocarcinoma.

Transporter-Mediated Drug Delivery

Transmembrane transport of small organic and inorganic molecules is one of the cornerstones of cellular metabolism. Among transmembrane transporters, solute carrier (SLC) proteins form the largest, albeit very diverse, superfamily with over 400 members. It was recognized early on that xenobiotics can directly interact with SLCs and that this interaction can fundamentally determine their efficacy, including bioavailability and intertissue distribution. Apart from the well-established prodrug strategy, the chemical ligation of transporter substrates to nanoparticles of various chemical compositions has recently been used as a means to enhance their targeting and absorption. In this review, we summarize efforts in drug design exploiting interactions with specific SLC transporters to optimize their therapeutic effects. Furthermore, we describe current and future challenges as well as new directions for the advanced development of therapeutics that target SLC transporters.

Revealing the contribution of astrocytes to glutamatergic neuronal transmission

Research on glutamatergic neurotransmission has focused mainly on the function of presynaptic and postsynaptic neurons, leaving astrocytes with a secondary role only to ensure successful neurotransmission. However, recent evidence indicates that astrocytes contribute actively and even regulate neuronal transmission at different levels. This review establishes a framework by comparing glutamatergic components between neurons and astrocytes to examine how astrocytes modulate or otherwise influence neuronal transmission. We have included the most recent findings about the role of astrocytes in neurotransmission, allowing us to understand the complex network of neuron-astrocyte interactions. However, despite the knowledge of synaptic modulation by astrocytes, their contribution to specific physiological and pathological conditions remains to be elucidated. A full understanding of the astrocyte's role in neuronal processing could open fruitful new frontiers in the development of therapeutic applications.

MEX3A Mediates p53 Degradation to Suppress Ferroptosis and Facilitate Ovarian Cancer Tumorigenesis

Epithelial ovarian cancer is a highly heterogeneous and malignant female cancer with an overall low survival rate. Mutations in p53 are prevalent in the major ovarian cancer histotype, high-grade serous ovarian carcinoma (HGSOC), while p53 mutations are much less frequent in other ovarian cancer subtypes, particularly in ovarian clear cell carcinoma (OCCC). Advanced stage OCCC with wild-type (WT) p53 has a worse prognosis and increased drug resistance, metastasis, and recurrence than HGSOC. The mechanisms responsible for driving the aggressiveness of WT p53-expressing ovarian cancer remain poorly understood. Here, we found that upregulation of MEX3A, a dual-function protein containing a RING finger domain and an RNA-binding domain, was critical for tumorigenesis in WT p53-expressing ovarian cancer. MEX3A overexpression enhanced the growth and clonogenicity of OCCC cell lines. In contrast, depletion of MEX3A in OCCC cells, as well as ovarian teratocarcinoma cells, reduced cell survival and proliferative ability. MEX3A depletion also inhibited tumor growth and prolonged survival in orthotopic xenograft models. MEX3A depletion did not alter p53 mRNA level but did increase p53 protein stability. MEX3A-mediated p53 protein degradation was crucial to suppress ferroptosis and enhance tumorigenesis. Consistently, p53 knockdown reversed the effects of MEX3A depletion. Together, our observations identified MEX3A as an important oncogenic factor promoting tumorigenesis in ovarian cancer cells expressing WT p53.

SIGNIFICANCE

Degradation of p53 mediated by MEX3A drives ovarian cancer growth by circumventing p53 tumor suppressive functions, suggesting targeting MEX3A as a potential strategy for treating of ovarian cancer expressing WT p53.

An anti-CD98 antibody displaying pH-dependent Fc-mediated tumour-specific activity against multiple cancers in CD98-humanized mice

The cell-surface glycoprotein CD98-a subunit of the LAT1/CD98 amino acid transporter-is an attractive target for cancer immunotherapies, but its widespread expression has hampered the development of CD98-targeting antibody therapeutics. Here we report that an anti-CD98 antibody, identified via the screening of phage-display libraries of CD98 single-chain variable fragments with mutated complementarity-determining regions, preserves the physiological function of CD98 and elicits broad-spectrum crystallizable-fragment (Fc)-mediated anti-tumour activity (requiring Fcγ receptors for immunoglobulins, macrophages, dendritic cells and CD8⁺ T cells, as well as other components of the innate and adaptive immune systems) in multiple xenograft and syngeneic tumour models established in CD98-humanized mice. We also show that a variant of the anti-CD98 antibody with pH-dependent binding, generated by solving the structure of the antibody-CD98 complex, displayed enhanced tumour-specific activity and pharmacokinetics. pH-dependent antibody variants targeting widely expressed antigens may lead to superior therapeutic outcomes.

Characterization of substrates and inhibitors of the human heterodimeric transporter 4F2hc-LAT1 using purified protein and the scintillation proximity radioligand binding assay

Amino acids have diverse and essential roles in many cellular functions such as in protein synthesis, metabolism and as precursors of different hormones. Translocation of amino acids and derivatives thereof across biological membranes is mediated by amino acid transporters. 4F2hc-LAT1 is a heterodimeric amino acid transporter that is composed of two subunits belonging to the SLC3 (4F2hc) and SLC7 (LAT1) solute carrier families. The ancillary protein 4F2hc is responsible for the correct trafficking and regulation of the transporter LAT1. Preclinical studies have identified 4F2hc-LAT1 as a valid anticancer target due to its importance in tumor progression. The scintillation proximity assay (SPA) is a valuable radioligand binding assay that allows the identification and characterization of ligands of membrane proteins. Here, we present a SPA ligand binding study using purified recombinant human 4F2hc-LAT1 protein and the radioligand [³H]L-leucine as tracer. Binding affinities of different 4F2hc-LAT1 substrates and inhibitors determined by SPA are comparable with previously reported K _m and IC ₅₀ values from 4F2hc-LAT1 cell-based uptake assays. In summary, the SPA is a valuable method for the identification and characterization of ligands of membrane transporters including inhibitors. In contrast to cell-based assays, where the potential interference with other proteins such as endogenous transporters persists, the SPA uses purified protein making target engagement and characterization of ligands highly reliable.

Lack of L-type amino acid transporter 2 in murine thyroid tissue induces autophagy

Proteolytic cleavage of thyroglobulin (Tg) for thyroid hormone (TH) liberation is followed by TH release from thyroid follicles into the circulation, enabled by TH transporters. The existence of a functional link between Tg-processing cathepsin proteases and TH transporters has been shown to be independent of the hypothalamus-pituitary-thyroid axis. Thus, lack of cathepsin K, combined with genetic defects in the TH transporters Mct8 and Mct10, that is the Ctsk-/-/Mct8-/y/Mct10-/- genotype, results in persistent Tg proteolysis due to autophagy induction. Because amino acid transport by L-type amino acid transporter 2 (Lat2) has been described to regulate autophagy, we asked whether Lat2 availability is affected in Ctsk-/-/Mct8-/y/Mct10-/- thyroid glands. Our data revealed that while mRNA amounts and subcellular localization of Lat2 remained unaltered in thyroid tissue of Ctsk-/-/Mct8-/y/Mct10-/- mice in comparison to WT controls, the Lat2 protein amounts were significantly reduced. These data suggest a direct link between Lat2 function and autophagy induction in Ctsk-/-/Mct8-/y/Mct10-/- mice. Indeed, thyroid tissue of Lat2-/- mice showed enhanced endo-lysosomal cathepsin activities, increased autophagosome formation, and enhanced autophagic flux. Collectively, these results suggest a mechanistic link between insufficient Lat2 protein function and autophagy induction in the thyroid gland of male mice.

Licochalcone A Induces Ferroptosis in Hepatocellular Carcinoma via Reactive Oxygen Species Activated by the SLC7A11/GPX4 Pathway

Liver cancer is a common malignant tumor, and its incidence is increasing yearly. Millions of people suffer from liver cancer annually, which has a serious impact on global public health security. Licochalcone A (Lico A), an important component of the traditional Chinese herb licorice, is a natural small molecule drug with multiple pharmacological activities. In this study, we evaluated the inhibitory effects of Lico A on hepatocellular carcinoma cell lines (HepG2 and Huh-7), and explored the inhibitory mechanism of Lico A on hepatocellular carcinoma. First, we evaluated the inhibitory effects of Lico A on hepatocellular carcinoma, and showed that Lico A significantly inhibited and killed HepG2 and Huh-7 cells in vivo and in vitro. Transcriptomic analysis showed that Lico A inhibited the expression of solute carrier family 7 member 11 (SLC7A11), which induced ferroptosis. We confirmed through in vivo and in vitro experiments that Lico A promoted ferroptosis in hepatocellular carcinoma cells by downregulating SLC7A11 expression, thereby inhibiting the glutathione (GSH)-glutathione peroxidase 4 (GPX4) pathway and inducing activation of reactive oxygen species (ROS). In this study, we suggest that Lico A is a potential SLC7A11 inhibitor that induces ferroptotic death in hepatocellular carcinoma cells, thereby providing a theoretical basis for the development of natural small molecule drugs against hepatocellular carcinoma.

The initiator of neuroexcitotoxicity and ferroptosis in ischemic stroke: Glutamate accumulation

Glutamate plays an important role in excitotoxicity and ferroptosis. Excitotoxicity occurs through over-stimulation of glutamate receptors, specifically NMDAR, while in the non-receptor-mediated pathway, high glutamate concentrations reduce cystine uptake by inhibiting the System Xc-, leading to intracellular glutathione depletion and resulting in ROS accumulation, which contributes to increased lipid peroxidation, mitochondrial damage, and ultimately ferroptosis. Oxidative stress appears to crosstalk between excitotoxicity and ferroptosis, and it is essential to maintain glutamate homeostasis and inhibit oxidative stress responses in vivo. As researchers work to develop natural compounds to further investigate the complex mechanisms and regulatory functions of ferroptosis and excitotoxicity, new avenues will be available for the effective treatment of ischaemic stroke. Therefore, this paper provides a review of the molecular mechanisms and treatment of glutamate-mediated excitotoxicity and ferroptosis.

Defective autophagy triggered by arterial cyclic stretch promotes neointimal hyperplasia in vein grafts via the p62/nrf2/slc7a11 signaling pathway

Autophagy is an adaptation mechanism to keep cellular homeostasis, and its deregulation is implicated in various cardiovascular diseases. After vein grafting, hemodynamic factors play crucial roles in neointimal hyperplasia, but the mechanisms are poorly understood. Here, we investigated the impacts of arterial cyclic stretch on autophagy of venous smooth muscle cells (SMCs) and its role in neointima formation after vein grafting. Rat jugular vein graft were generated via the 'cuff' technique. Autophagic flux in venous SMCs is impaired in 3-day, 1-week and 2-week grafted veins. 10%-1.25 Hz cyclic stretch (arterial stretch) loaded with FX5000 stretch system on venous SMCs blocks cellular autophagic flux in vitro and shows no significant impact on activity of mTORC1 and AMPK. Microtubule depolymerization but not lysosome dysfunction nor autophagosome/amphisome-lysosomal membrane fusion blockade is involved in the impairment of autophagic flux. Microtubule stabilization, induced by paclitaxel treatment and external stents intervention respectively, restores venous SMC autophagy and ameliorates neointimal hyperplasia in vivo. Moreover, autophagy impairment causes accumulation of the cargo receptor p62, which sequesters keap1 to p62 aggregates and results in the stabilization and nuclear translocation of nrf2 to modulate its target antioxidative gene SLC7A11. p62 silencing abrogates the increases of nrf2 and slc7a11 protein expression, glutathione level and venous SMC proliferation triggered by arterial cyclic stretch in vitro, and further hinders nrf2 nuclear translocation, reduces neointimal thickness after vein grafting in vivo. p62 (T349A) mutation also inhibited venous SMC proliferation and alleviated neointimal formation in vivo. These findings suggest that stabilization of microtubules to rescue autophagic flux or direct silencing of p62 are potential therapeutic strategies for neointimal hyperplasia.

Ferroptosis increases obesity: Crosstalk between adipocytes and the neuroimmune system

Ferroptosis requires not only the accumulation of iron ions, but also changes in many ferroptosis-related regulators, including a decrease in GPX4 and inhibition of SLC7A11 for classical ferroptosis, a deletion of FSP1 or GCH1. Surprisingly, adipose tissue (AT) in the obesity conditions is also accompanied by iron buildup, decreased GSH, and increased ROS. On the neurological side, the pro-inflammatory factor released by AT may have first caused ferroptosis in the vagus nerve by inhibiting of the NRF2-GPX4 pathway, resulting in disorders of the autonomic nervous system. On the immune side, obesity may cause M2 macrophages ferroptosis due to damage to iron-rich ATMs (MFe^hi) and antioxidant ATMs (Mox), and lead to Treg cells ferroptosis through reductions in NRF2, GPX4, and GCH1 levels. At the same time, the reduction in GPX4 may also trigger the ferroptosis of B1 cells. In addition, some studies have also found the role of GPX4 in neutrophil autophagy, which is also worth pondering whether there is a connection with ferroptosis. In conclusion, this review summarizes the associations between neuroimmune regulation associated with obesity and ferroptosis, and on the basis of this, highlights their potential molecular mechanisms, proposing that ferroptosis in one or more cells in a multicellular tissue changes the fate of that tissue.