USP8-governed GPX4 homeostasis orchestrates ferroptosis and cancer immunotherapy.

Ferroptosis is an iron-dependent type of regulated cell death resulting from extensive lipid peroxidation and plays a critical role in various physiological and pathological processes. However, the regulatory mechanisms for ferroptosis sensitivity remain incompletely understood. Here, we report that homozygous deletion of Usp8 (ubiquitin-specific protease 8) in intestinal epithelial cells (IECs) leads to architectural changes in the colonic epithelium and shortens mouse lifespan accompanied by increased IEC death and signs of lipid peroxidation. However, mice with heterozygous deletion of Usp8 in IECs display normal phenotype and become resistant to azoxymethane/dextran sodium sulfate-induced colorectal tumorigenesis. Mechanistically, USP8 interacts with and deubiquitinates glutathione peroxidase 4 (GPX4), leading to GPX4 stabilization. Thus, USP8 inhibition destabilizes GPX4 and sensitizes cancer cells to ferroptosis in vitro. Notably, USP8 inhibition in combination with ferroptosis inducers retards tumor growth and enhances CD8+ T cell infiltration, which potentiates tumor response to anti-PD-1 immunotherapy in vivo. These findings uncover that USP8 counteracts ferroptosis by stabilizing GPX4 and highlight targeting USP8 as a potential therapeutic strategy to boost ferroptosis for enhancing cancer immunotherapy.

Depletion of the N6-Methyladenosine (m6A) reader protein IGF2BP3 induces ferroptosis in glioma by modulating the expression of GPX4.

Emerging evidence highlights the multifaceted contributions of m6A modifications to glioma. IGF2BP3, a m6A modification reader protein, plays a crucial role in post-transcriptional gene regulation. Though several studies have identified IGF2BP3 as a poor prognostic marker in glioma, the underlying mechanism remains unclear. In this study, we demonstrated that IGF2BP3 knockdown is detrimental to cell growth and survival in glioma cells. Notably, we discovered that IGF2BP3 regulated ferroptosis by modulating the protein expression level of GPX4 through direct binding to a specific motif on GPX4 mRNA. Strikingly, the m6A modification at this motif was found to be critical for GPX4 mRNA stability and translation. Furthermore, IGF2BP3 knockdown glioma cells were incapable of forming tumors in a mouse xenograft model and were more susceptible to phagocytosis by microglia. Our findings shed light on an unrecognized regulatory function of IGF2BP3 in ferroptosis. The identification of a critical m6A site within the GPX4 transcript elucidates the significance of post-transcriptional control in ferroptosis.

Moderate mechanical stress suppresses chondrocyte ferroptosis in osteoarthritis by regulating NF-κB p65/GPX4 signaling pathway.

Ferroptosis is a recently identified form of programmed cell death that plays an important role in the pathophysiological process of osteoarthritis (OA). Herein, we investigated the protective effect of moderate mechanical stress on chondrocyte ferroptosis and further revealed the internal molecular mechanism. Intra-articular injection of sodium iodoacetate (MIA) was conducted to induce the rat model of OA in vivo, meanwhile, interleukin-1 beta (IL-1ß) was treated to chondrocytes to induce the OA cell model in vitro. The OA phenotype was analyzed by histology and microcomputed tomography, the ferroptosis was analyzed by transmission electron microscope and immunofluorescence. The expression of ferroptosis and cartilage metabolism-related factors was analyzed by immunohistochemical and Western blot. Animal experiments revealed that moderate-intensity treadmill exercise could effectively reduce chondrocyte ferroptosis and cartilage matrix degradation in MIA-induced OA rats. Cell experiments showed that 4-h cyclic tensile strain intervention could activate Nrf2 and inhibit the NF-κB signaling pathway, increase the expression of Col2a1, GPX4, and SLC7A11, decrease the expression of MMP13 and P53, thereby restraining IL-1ß-induced chondrocyte ferroptosis and degeneration. Inhibition of NF-κB signaling pathway relieved the chondrocyte ferroptosis and degeneration. Meanwhile, overexpression of NF-κB by recombinant lentivirus reversed the positive effect of CTS on chondrocytes. Moderate mechanical stress could activate the Nrf2 antioxidant system, inhibit the NF-κB p65 signaling pathway, and inhibit chondrocyte ferroptosis and cartilage matrix degradation by regulating P53, SLC7A11, and GPX4.

CD8+ T cells sustain antitumor response by mediating crosstalk between adenosine A2A receptor and glutathione/GPX4.

Antitumor responses of CD8+ T cells are tightly regulated by distinct metabolic fitness. High levels of glutathione (GSH) are observed in the majority of tumors, contributing to cancer progression and treatment resistance in part by preventing glutathione peroxidase 4-dependent (GPX4-dependent) ferroptosis. Here, we show the necessity of adenosine A2A receptor (A2AR) signaling and the GSH/GPX4 axis in orchestrating metabolic fitness and survival of functionally competent CD8+ T cells. Activated CD8+ T cells treated ex vivo with simultaneous inhibition of A2AR and lipid peroxidation acquire a superior capacity to proliferate and persist in vivo, demonstrating a translatable means to prevent ferroptosis in adoptive cell therapy. Additionally, we identify a particular cluster of intratumoral CD8+ T cells expressing a putative gene signature of GSH metabolism (GMGS) in association with clinical response and survival across several human cancers. Our study addresses a key role of GSH/GPX4 and adenosinergic pathways in fine-tuning the metabolic fitness of antitumor CD8+ T cells.

Hypermethylation of the glutathione peroxidase 4 gene promoter is associated with the occurrence of immune tolerance phase in chronic hepatitis B.

BACKGROUND: Hepatitis B virus (HBV) infection is a public health problem that seriously threatens human health. This study aimed to investigate the clinical significance of glutathione peroxidase 4(GPX4) in the occurrence and development of chronic hepatitis B (CHB). METHODS: A total of 169 participants including 137 patients with CHB and 32 healthy controls (HCs) were recruited. We detected the expression of GPX4 and stimulator of interferon genes (STING) in peripheral blood mononuclear cells (PBMCs) by real-time quantitative polymerase chain reaction (RT-qPCR). The methylation level of GPX4 gene promoter in PBMCs was detected by TaqMan probe-based quantitative methylation-specific PCR (MethyLight). Enzyme-linked immunosorbent assay (ELISA) was performed to detect the serum levels of GPX4, IFN-ß, oxidative stress (OS) related molecules, and pro-inflammatory cytokines. RESULTS: The expression levels of GPX4 in PBMCs and serum of CHB patients were lower than those of HCs, but the methylation levels of GPX4 promoter were higher than those of HCs, especially in patients at the immune tolerance phase. STING mRNA expression levels in PBMCs and serum IFN-ß levels of patients at the immune activation phase and reactivation phase of CHB were higher than those at other clinical phases of CHB and HCs. GPX4 mRNA expression level and methylation level in PBMCs from patients with CHB had a certain correlation with STING and IFN-ß expression levels. In addition, the methylation level of the GPX4 promoter in PBMCs from patients with CHB was correlated with molecules associated with OS and inflammation. CONCLUSIONS: GPX4 may play an important role in the pathogenesis and immune tolerance of CHB, which may provide new ideas for the functional cure of CHB.

Expression and Significance of BCCIP and Glutathione Peroxidase 4 in Clear Cell Renal Cell Carcinoma.

In this retrospective study involving 112 patients with clear cell renal cell carcinoma (ccRCC), we analyzed clinical significance and prognostic value of the expression of BCCIP protein interacting with BRCA2 and CDKN1A and glutathione peroxidase 4 (GPX4). The expressions of mRNA and the corresponding proteins were evaluated using reverse transcription PCR and immunohistochemistry. In comparison with control samples of renal peritumoral tissue, the expressions of BCCIP and its mRNA in the tumor tissues were significantly down-regulated, while the expressions of GPX4 and the corresponding mRNA were significantly up-regulated. The down-regulation of BCCIP expression was closely related to histological grade, TNM stage, and lymph node metastasis (p<0.05). The GPX4 overexpression was closely related to tumor size, TNM stage, and the presence of distant metastasis. The Kaplan-Meier survival analysis showed that tumor size, TNM stage, lymph node metastasis, distant metastasis, expressions of BCCIP and GPX4 correlated with progression-free survival (p<0.05). Multivariate Cox regression showed that down-regulation of BCCIP expression and overexpression of GPX4, TNM stage, and distant metastasis were independent prognostic factors of progression-free survival. Thus, down-regulation of BCCIP expression and overexpression of GPX4 are indicatives of progression of ccRCC with poor prognosis. Hence, the control of expression of these proteins can be considered as a novel target for the treatment of ccRCC.

A tangible method to assess native ferroptosis suppressor activity.

Ferroptosis, a regulated cell death hallmarked by unrestrained lipid peroxidation, plays a pivotal role in the pathophysiology of various diseases, making it a promising therapeutic target. Glutathione peroxidase 4 (GPX4) prevents ferroptosis by reducing (phospho)lipid hydroperoxides, yet evaluation of its actual activity has remained arduous. Here, we present a tangible method using affinity-purified GPX4 to capture a snapshot of its native activity. Next to measuring GPX4 activity, this improved method allows for the investigation of mutational GPX4 activity, exemplified by the GPX4U46C mutant lacking selenocysteine at its active site, as well as the evaluation of GPX4 inhibitors, such as RSL3, as a showcase. Furthermore, we apply this method to the second ferroptosis guardian, ferroptosis suppressor protein 1, to validate the newly identified ferroptosis inhibitor WIN62577. Together, these methods open up opportunities for evaluating alternative ferroptosis suppression mechanisms.

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.

Selenium-SelK-GPX4 axis protects nucleus pulposus cells against mechanical overloading-induced ferroptosis and attenuates senescence of intervertebral disc.

Intervertebral disc degeneration (IVDD) is one of the most prevalent spinal degenerative disorders and imposes places heavy medical and economic burdens on individuals and society. Mechanical overloading applied to the intervertebral disc (IVD) has been widely recognized as an important cause of IVDD. Mechanical overloading-induced chondrocyte ferroptosis was reported, but the potential association between ferroptosis and mechanical overloading remains to be illustrated in nucleus pulposus (NP) cells. In this study, we discovered that excessive mechanical loading induced ferroptosis and endoplasmic reticulum (ER) stress, which were detected by mitochondria and associated markers, by increasing the intracellular free Ca2+ level through the Piezo1 ion channel localized on the plasma membrane and ER membrane in NP cells. Besides, we proposed that intracellular free Ca2+ level elevation and the activation of ER stress are positive feedback processes that promote each other, consistent with the results that the level of ER stress in coccygeal discs of aged Piezo1-CKO mice were significantly lower than that of aged WT mice. Then, we confirmed that selenium supplementation decreased intracellular free Ca2+ level by mitigating ER stress through upregulating Selenoprotein K (SelK) expression. Besides, ferroptosis caused by the impaired production and function of Glutathione peroxidase 4 (GPX4) due to mechanical overloading-induced calcium overload could be improved by selenium supplementation through Se-GPX4 axis and Se-SelK axis in vivo and in vitro, eventually presenting the stabilization of the extracellular matrix (ECM). Our findings reveal the important role of ferroptosis in mechanical overloading-induced IVDD, and selenium supplementation promotes significance to attenuate ferroptosis and thus alleviates IVDD, which might provide insights into potential therapeutic interventions for IVDD.

The selenium-independent phospholipid hydroperoxide glutathione peroxidase from Theobroma cacao (TcPHGPX) protects plant cells against damages and cell death.

Proteins from the glutathione peroxidase (GPX) family, such as GPX4 or PHGPX in animals, are extensively studied for their antioxidant functions and apoptosis inhibition. GPXs can be selenium-independent or selenium-dependent, with selenium acting as a potential cofactor for GPX activity. However, the relationship of plant GPXs to these functions remains unclear. Recent research indicated an upregulation of Theobroma cacao phospholipid hydroperoxide glutathione peroxidase gene (TcPHGPX) expression during early witches' broom disease stages, suggesting the use of antioxidant mechanisms as a plant defense strategy to reduce disease progression. Witches' broom disease, caused by the hemibiotrophic fungus Moniliophthora perniciosa, induces cell death through elicitors like MpNEP2 in advanced infection stages. In this context, in silico and in vitro analyses of TcPHGPX's physicochemical and functional characteristics may elucidate its antioxidant potential and effects against cell death, enhancing understanding of plant GPXs and informing strategies to control witches' broom disease. Results indicated TcPHGPX interaction with selenium compounds, mainly sodium selenite, but without improving the protein function. Protein-protein interaction network suggested cacao GPXs association with glutathione and thioredoxin metabolism, engaging in pathways like signaling, peroxide detection for ABA pathway components, and anthocyanin transport. Tests on tobacco cells revealed that TcPHGPX reduced cell death, associated with decreased membrane damage and H2O2 production induced by MpNEP2. This study is the first functional analysis of TcPHGPX, contributing to knowledge about plant GPXs and supporting studies for witches' broom disease control.

A potent GPX4 degrader to induce ferroptosis in HT1080 cells.

Glutathione peroxidase 4 (GPX4) is the most promising target for inducing ferroptosis. GPX4-targeting strategies primarily focus on inhibiting its activity or adjusting its cellular level. However, small inhibitors have limitations due to the covalent reactive alkyl chloride moiety, which could lead to poor selectivity and suboptimal pharmacokinetic properties. Herein, we designed and synthesized a series of proteolysis targeting chimeras (PROTACs) by connecting RSL3, a small molecule inhibitor of GPX4, with six different ubiquitin ligase ligands. As a highly effective degrader, compound 18a is a potent degrader (DC50, 48h = 1.68 µM, Dmax, 48h = 85 %). It also showed an obvious anti-proliferative effect with the IC50 value of 2.37 ± 0.17 µM in HT1080. Mechanism research showed that compound 18a formed a ternary complex with GPX4 and cIAP and induced the degradation of GPX4 through the ubiquitin-proteasome system pathway. Furthermore, compound 18a also induced the accumulation of lipid peroxides and mitochondrial depolarization, subsequently triggering ferroptosis. Our work demonstrated the practicality and efficiency of the PROTAC strategy and offered a promising avenue for designing degraders to induce ferroptosis in cancer cells.

Novel Covalent Probe Selectively Targeting Glutathione Peroxidase 4 In Vivo: Potential Applications in Pancreatic Cancer Therapy.

Glutathione peroxidase 4 (GPX4) emerges as a promising target for the treatment of therapy-resistant cancer through ferroptosis. Thus, there is a broad interest in the development of GPX4 inhibitors. However, a majority of reported GPX4 inhibitors utilize chloroacetamide as a reactive electrophilic warhead, and the selectivity and pharmacokinetic properties still need to be improved. Herein, we developed a compound library based on a novel electrophilic warhead, the sulfonyl ynamide, and executed phenotypic screening against pancreatic cancer cell lines. Notably, one compound A16 exhibiting potent cell toxicity was identified. Further chemical proteomics investigations have demonstrated that A16 specifically targets GPX4 under both in situ and in vivo conditions, inducing ferroptosis. Importantly, A16 exhibited superior selectivity and potency compared to reported GPX4 inhibitors, ML210 and ML162. This provides the structural diversity of tool probes for unraveling the fundamental biology of GPX4 and exploring the therapeutic potential of pancreatic cancer via ferroptosis induction.

Design, Synthesis, and Biological Evaluation of Hydrophobic-Tagged Glutathione Peroxidase 4 (GPX4) Degraders.

Ferroptosis is an iron-dependent form of oxidative cell death induced by lipid peroxidation accumulation. Glutathione peroxidase 4 (GPX4) plays a key role in the regulation of ferroptosis and is considered to be a promising therapeutic target for cancer and other human diseases. Herein, we describe our design, synthesis, and biological evaluation of a series of HyT-based degraders of the GPX4. One of the most promising compounds, 7b (ZX782), effectively induces dose- and time-dependent degradation of GPX4 protein and potently suppresses the growth of human fibrosarcoma HT1080 cells, which are highly sensitive to ferroptosis and widely used for evaluating compound specificity in ferroptosis. Mechanism investigation indicated that 7b depletes GPX4 through both the ubiquitin-proteasome and the autophagy-lysosome. Furthermore, the degradation of GPX4 induced by 7b could significantly increase the accumulation of lipid reactive oxygen species (ROS) in HT1080 cells, ultimately leading to ferroptosis. Overall, compound 7b exhibits robust potency in depleting endogenous GPX4, thereby modulating ferroptosis in cancer cells.

Natural product-derived ferroptosis mediators.

It has been 11 years since ferroptosis, a new mode of programmed cell death, was first proposed. Natural products are an important source of drug discovery. In the past five years, natural product-derived ferroptosis regulators have been discovered in an endless stream. Herein, 178 natural products discovered so far to trigger or resist ferroptosis are classified into 6 structural classes based on skeleton type, and the mechanisms of action that have been reported are elaborated upon. If pharmacodynamic data are sufficient, the structure and bioactivity relationship is also presented. This review will provide medicinal chemists with some effective ferroptosis regulators, which will promote the research of natural product-based treatment of ferroptosis-related diseases in the future.

Advancing the frontiers of colorectal cancer treatment: harnessing ferroptosis regulation.

In recent years, colorectal cancer incidence and mortality have increased significantly due to poor lifestyle choices. Despite the development of various treatments, their effectiveness against advanced/metastatic colorectal cancer remains unsatisfactory due to drug resistance. However, ferroptosis, a novel iron-dependent cell death process induced by lipid peroxidation and elevated reactive oxygen species (ROS) levels along with reduced activity of the glutathione peroxidase 4 (GPX4) antioxidant enzyme system, shows promise as a therapeutic target for colorectal cancer. This review aims to delve into the regulatory mechanisms of ferroptosis in colorectal cancer, providing valuable insights into potential therapeutic approaches. By targeting ferroptosis, new avenues can be explored for innovative therapies to combat colorectal cancer more effectively. In addition, understanding the molecular pathways involved in ferroptosis may help identify biomarkers for prognosis and treatment response, paving the way for personalized medicine approaches. Furthermore, exploring the interplay between ferroptosis and other cellular processes can uncover combination therapies that enhance treatment efficacy. Investigating the tumor microenvironment's role in regulating ferroptosis may offer strategies to sensitize cancer cells to cell death induction, leading to improved outcomes. Overall, ferroptosis presents a promising avenue for advancing the treatment of colorectal cancer and improving patient outcomes.

Sensitization of cancer cells to ferroptosis coincident with cell cycle arrest.

Ferroptosis is a non-apoptotic form of cell death that can be triggered by inhibiting the system xc- cystine/glutamate antiporter or the phospholipid hydroperoxidase glutathione peroxidase 4 (GPX4). We have investigated how cell cycle arrest caused by stabilization of p53 or inhibition of cyclin-dependent kinase 4/6 (CDK4/6) impacts ferroptosis sensitivity. Here, we show that cell cycle arrest can enhance sensitivity to ferroptosis induced by covalent GPX4 inhibitors (GPX4i) but not system xc- inhibitors. Greater sensitivity to GPX4i is associated with increased levels of oxidizable polyunsaturated fatty acid-containing phospholipids (PUFA-PLs). Higher PUFA-PL abundance upon cell cycle arrest involves reduced expression of membrane-bound O-acyltransferase domain-containing 1 (MBOAT1) and epithelial membrane protein 2 (EMP2). A candidate orally bioavailable GPX4 inhibitor increases lipid peroxidation and shrinks tumor volumes when combined with a CDK4/6 inhibitor. Thus, cell cycle arrest may make certain cancer cells more susceptible to ferroptosis in vivo.

Magnetic graphene oxide nanocomposites induce cytotoxicity in ADSCs via GPX4 regulating ferroptosis.

Magnetic graphene oxide nanocomposites (MGO NPs) have been widely studied in biomedical applications. However, their cytotoxicity and underlying mechanisms remain unclear. In this study, the biosafety of MGO NPs was investigated, and the mechanism involved in ferroptosis was further explored. MGO can produce cytotoxicity in ADSCs, which is dependent on their concentration. Ferroptosis was involved in MGO NP-induced ADSC survival inhibition by increasing total ROS and lipid ROS accumulation as well as regulating the expression levels of ferroptosis-related genes and proteins. GPX4 played a critical role in the MGO NP-induced ADSC ferroptosis process, and overexpressing GPX4 suppressed ferroptosis to increase cell survival. This study provides a theoretical basis for the biosafety management of MGO NPs used in the field of biomedical treatment.

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

BACKGROUNDS: Hepatitis B virus infection could result in male infertility with sperm defects and dysfunction. Sertoli cells are essential for testis function and play a crucial role in spermatogenesis. Sertoli cell death contributes to spermatogenesis impairment, leading to poor sperm quality. Ferroptosis has been implicated as a mechanism of Sertoli cell death. The issue in studying the relationship between hepatitis B virus and Sertoli cell ferroptosis has not yet been addressed. OBJECTIVES: To explore the mechanisms underlying ferroptosis in hepatitis B virus-exposed Sertoli cells. MATERIALS AND METHODS: Human Sertoli cells were treated in vitro with levels of 25, 50, and 100 µg/mL of hepatitis B virus surface protein (HBs). Cell viability and levels of glutathione, malondialdehyde, cellular ferrous ion (Fe2+ ), lipid peroxidation, and N6-methyladenosine in Sertoli cells were detected. The level of glutathione peroxidase 4, transferrin receptor 1, ferritin heavy chain, tripartite motif (TRIM) 37, methyltransferase like 3, and insulin-like growth factor 2 mRNA binding protein 2 was examined. Cell transfection was carried out to alter expression of ferroptosis-related proteins. qPCR and immunoblotting were performed to measure protein expression level. Immunoprecipitation was applied to determine the protein and protein-RNA interaction. Luminescence analysis was performed to identify the target of methyltransferase like 3. RESULTS: HBs exposure triggered ferroptosis featured with increased intracellular Fe2+ ion, reduced cell viability and expression of glutathione peroxidase 4 in Sertoli cells. HBs treatment significantly increased TRIM37 expression, which suppressed glutathione peroxidase 4 expression through ubiquitination. TRIM37 silencing attenuated the effect of HBs exposure-regulated cell viability and ferroptosis. HBs upregulated N6-methyladenosine modification in TRIM37 3'-UTR by increasing methyltransferase like 3 expression. The binding of N6-methyladenosine reader insulin-like growth factor 2 mRNA binding protein 2 and TRIM37 3'-UTR enhanced the stability of TRIM37 mRNA. CONCLUSION: HBs can decrease human Sertoli cell viability by promoting ferroptosis induced by the loss of glutathione peroxidase 4 activity through TRIM37-mediated ubiquitination of glutathione peroxidase 4. The findings highlight the role of TRIM37/glutathione peroxidase 4 signaling responsible for ferroptosis regulation in hepatitis B virus-infected Sertoli cells.

Oxytosis/Ferroptosis in Neurodegeneration: the Underlying Role of Master Regulator Glutathione Peroxidase 4 (GPX4).

Oxytosis/ferroptosis is an iron-dependent oxidative form of cell death triggered by lethal accumulation of phospholipid hydroperoxides (PLOOHs) in membranes. Failure of the intricate PLOOH repair system is a principle cause of ferroptotic cell death. Glutathione peroxidase 4 (GPX4) is distinctly vital for converting PLOOHs in membranes to non-toxic alcohols. As such, GPX4 is known as the master regulator of oxytosis/ferroptosis. Ferroptosis has been implicated in a number of disorders such as neurodegenerative diseases (amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD), etc.), ischemia/reperfusion injury, and kidney degeneration. Reduced function of GPX4 is frequently observed in degenerative disorders. In this study, we examine how diminished GPX4 function may be a critical event in triggering oxytosis/ferroptosis to perpetuate or initiate the neurodegenerative diseases and assess the possible therapeutic importance of oxytosis/ferroptosis in neurodegenerative disorders. These discoveries are important for advancing our understanding of neurodegenerative diseases because oxytosis/ferroptosis may provide a new target to slow the course of the disease.

Ferroptosis-related gene glutathione peroxidase 4 promotes reprogramming of glucose metabolism via Akt-mTOR axis in intrahepatic cholangiocarcinoma.

The role of the ferroptosis-related gene glutathione peroxidase 4 (GPX4) in oncology has been extensively investigated. However, the clinical implications of GPX4 in patients with intrahepatic cholangiocarcinoma (ICC) remain unknown. This study aimed to evaluate the prognostic impact of GPX4 and its underlying molecular mechanisms in patients with ICC. Fifty-seven patients who underwent surgical resection for ICC between 2010 and 2017 were retrospectively analyzed. Based on the immunohistochemistry, patients were divided into GPX4 high (n = 15) and low (n = 42) groups, and clinical outcomes were assessed. Furthermore, the roles of GPX4 in cell proliferation, migration and gene expression were analyzed in ICC cell lines in vitro and in vivo. The results from clinical study showed that GPX4 high group showed significant associations with high SUVmax on 18F-fluorodeoxyglucose-positron emission tomography (≥8.0, P = 0.017), multiple tumors (P = 0.004), and showed glucose transporter 1 (GLUT1) high expression with a trend toward significance (P = 0.053). Overall and recurrence-free survival in the GPX4 high expression group were significantly worse than those in the GPX4 low expression group (P = 0.038 and P < 0.001, respectively). In the experimental study, inhibition of GPX4 attenuated cell proliferation and migration in ICC cell lines. Inhibition of GPX4 also decreased the expression of glucose metabolism-related genes, such as GLUT1 or HIF1α. Mechanistically, these molecular changes are regulated in Akt-mechanistic targets of rapamycin axis. In conclusion, this study suggested the pivotal value of GPX4 serving as a prognostic marker for patients with ICC. Furthermore, GPX4 can mediate glucose metabolism of ICC.