FTY720 induces ferroptosis and autophagy via PP2A/AMPK pathway in multiple myeloma cells

Identification of RUVBL2 as a novel biomarker to predict the prognosis and drug sensitivity in multiple myeloma based on ferroptosis genes

BACKGROUND

Multiple myeloma (MM) is a hematological malignancy with the proliferation of malignant plasma cells. Numerous studies have highlighted the critical role of ferroptosis in MM. However, how to use ferroptosis-related genes (FRGs) for prognostic prediction and treatment guidance in MM remains unknown.

METHODS

By analysis of GEO databases, the prognostic gene was identified and a therapeutic strategy for MM patients based on FRGs was explored. A total of 12 FRGs were identified, utilizing the STRING database and Cytoscape software, and the PPI networks were constructed to identify hub genes and further functional enrichment analyses. Based on the aforementioned data, this study analyzed the expression of RUVBL2 in MM patients by qRT-PCR and Western blotting. To validate the functional role of RUVBL2 in the MM cells, cellular experiments were ultimately conducted.

RESULTS

The analysis highlighted six hub genes, including TP53, MCM5, TLR4, RUVBL2, GCLM and ITGA6, and functional enrichment analyses indicating enrichment in DNA replication, regulation of apoptotic signaling pathway and PI3K/AKT signaling pathway. Prognostic analysis indicated that TP53, RUVBL2, and MCM5 are associated with MM prognosis, with RUVBL2 displaying a notable area under the curve (AUC) of 0.823 in ROC analysis. The study first determined that RUVBL2 is highly expressed in MM, siRUVBL2-mediated deletion of RUVBL2 inhibited proliferation, promoted apoptosis and increased the sensitivity of BTZ in MM cells, and also overcame BTZ resistance in CD138+ primary cells from MM patients.

CONCLUSIONS

Our study first suggested that RUVBL2 may be regarded as potential therapeutic targets and prognostic value in MM.

Sephin1 suppresses ER stress-induced cell death by inhibiting the formation of PP2A holoenzyme

Sephin1 was discovered as a protein phosphatase inhibitor, and its efficacy against neurodegenerative diseases has been confirmed. There are conflicting reports on whether inhibition of eIF2α dephosphorylation by PP1 holoenzyme with the protein phosphatase 1 regulatory subunit 15 A is the mechanism of action of Sephin1. In the present study, we found that Sephin1 significantly suppressed renal tubular cell death in an animal model of ER stress administered with tunicamycin. CHOP, which plays a central role in the ER stress-induced cell death pathway, requires nuclear translocation to act as a transcription factor to increase the expression of cell death-related genes. Sephin1 markedly suppressed this nuclear translocation of CHOP. To elucidate the molecular mechanism underlying the cell death suppressive effect of Sephin1, we used human renal tubular epithelial cells under ER stress with tunicamycin. Sephin1 reduced intracellular CHOP levels by promoting CHOP phosphorylation at Ser30, which led to protein degradation in UPS. Phosphorylated CHOP is generated by Thr172-phosphorylated activated AMPK, and Sephin1 increased phosphorylated AMPK. Phosphorylated AMPK is inactivated by PP2A through dephosphorylation of its Thr172, and Sephin1 inhibits the formation of the PP2A holoenzyme with the PP2A subunit B isoform delta. These results indicate that inhibition of PP2A holoenzyme formation is the molecular target of Sephin1 in this experimental system.

Elongation factor 2 in cancer: a promising therapeutic target in protein translation

Aberrant elongation of proteins can lead to the activation of oncogenic signaling pathways, resulting in the dysregulation of oncogenic signaling pathways. Eukaryotic elongation factor 2 (eEF2) is an essential regulator of protein synthesis that precisely elongates nascent peptides in the protein elongation process. Although studies have linked aberrant eEF2 expression to various cancers, research has primarily focused on its structure, highlighting a need for deeper exploration into its molecular functions. In this review, recent advancements in the structure, guanosine triphosphatase (GTPase) activity, posttranslational modifications, regulatory factors, and inhibitors of eEF2 are summarized. These findings provide a comprehensive cognition on the critical role of eEF2 and its potential as a therapeutic target in cancer. Furthermore, this review highlights important unanswered questions that warrant investigation in future research.

Bone marrow stromal cells protect myeloma cells from ferroptosis through GPX4 deSUMOylation

Bone marrow stromal cells (BMSCs) are vital for preventing chemotherapy induced apoptosis of multiple myeloma (MM), but roles and machinery in other forms of cell death have not been well elucidated. Here, using an in vitro BMSC-MM interacting model, we observed BMSCs protected MM cells from labile iron pool (LIP) and reactive oxygen species (ROS) triggered ferroptosis by elevating glutathione peroxidase 4 (GPX4). Mechanistically, direct interaction with BMSCs upregulated the expression of SUMO-specific protease 3 (SENP3) in MM cells through CD40/CD40L signaling pathway, and SENP3 de-conjugated SUMO2 at lysine 75 residue to stabilize GPX4 protein, thereby consuming ROS to obviate ferroptosis in MM cells from the Vk∗MYC mouse model, as well as in CD138+B220- cells separated from the Cd40lfl/fl;Prx1Cre/+ mice (CD40-CKO) and Sumo2 knock out (SUMO2-KO) mice. Using the NOD-scid IL2Rgammanull (NSG) mouse based xenograft model and intra-bone MM growth model, we validated that target SENP3 enhanced the killing effect of GPX4 inhibitor RSL3, thereby reduced tumor burden, prolonged survival of mice, and alleviated bone disruption of mice bearing MM tumors. Our study deciphers the mechanism of BMSCs preventing MM cells from spontaneous ferroptosis, and clarifies the therapeutic potential of non-apoptosis strategies in managing refractory or relapsed MM patients.

The Role of AMP-activated Protein Kinase in Oxytosis/Ferroptosis: Protector or Potentiator?

Significance: Evidence for a role for the oxytosis/ferroptosis regulated cell death pathway in aging and neurodegenerative diseases has been growing over the past few years. Because of this, there is an increasing necessity to identify endogenous signaling pathways that can be modulated to protect cells from this form of cell death. Recent Advances: Recently, several studies have identified a protective role for the AMP-activated protein kinase (AMPK)/acetyl CoA carboxylase 1 (ACC1) pathway in oxytosis/ferroptosis. However, there are also a number of studies suggesting that this pathway contributes to cell death initiated by various inducers of oxytosis/ferroptosis. Critical Issues: The goals of this review are to provide an overview and analysis of the published studies and highlight specific areas where more research is needed. Future Directions: Much remains to be learned about AMPK signaling in oxytosis/ferroptosis, especially the conditions where it is protective. Furthermore, the role of AMPK signaling in the brain and especially the aging brain needs further investigation.

Class II ferroptosis inducers are a novel therapeutic approach for t(4;14)-positive multiple myeloma

ABSTRACT

Multiple myeloma (MM) is a clonal plasma cell malignancy that is characterized by genetic heterogeneity. The cytogenetic abnormality t(4;14) strongly predicts poor outcome in patients with MM, even in the era of novel drugs. Ferroptosis is a new approach to antitumor therapy, but the relationship between ferroptosis and MM cytogenetic abnormalities remains largely unclear. In this study, we show that t(4;14)-positive but not t(4;14)-negative MM cells are susceptible to class II ferroptosis inducers (FINs) in a preclinical setting, which is dependent on the significant upregulation of the MM SET domain-containing protein (MMSET). Mechanistically, MMSET upregulates acyl-coenzyme A synthetase long-chain family member 4 transcription by binding to its promoter region, leading to increased polyunsaturated fatty acid (PUFA) levels and enhanced sensitivity of t(4;14)-positive MM cells to ferroptosis. Supplementation with PUFAs efficiently restores the susceptibility of t(4;14)-negative MM cells to ferroptosis. In addition, combining class II FIN treatment with bortezomib in t(4;14)-positive MM cells attenuates cellular glutathione and induces both apoptosis and ferroptosis levels by inhibiting the increase in solute carrier family 7 member 11, demonstrating synergistic antitumor activity in vitro and in a xenograft model. Taken together, our findings suggest that targeting ferroptosis with class II FINs is a novel and promising therapeutic approach to improve the outcome of t(4;14)-positive patients with MM.

Research Progress on Ferroptosis in Multiple Myeloma

OPINION STATEMENT

Multiple myeloma (MM) is the second most common hematological malignant (HM) tumor, and a large proportion of patients still suffer from treatment failure and a poor prognosis despite the use of some newly approved drugs, a deeper understanding of the underlying mechanism is still needed. Ferroptosis is a new form of programmed cell death (PCD) that is different from other traditional forms of cell death such as apoptosis, necrosis and autophagy. With the continuous deepening of research on ferroptosis, ferroptosis has been found to be closely related to MM. This article reviews the regulatory mechanism of ferroptosis and research progress on ferroptosis in MM, providing a new theoretical basis and strategies for the diagnosis and treatment of MM.

Targeting Ferroptosis as an Advance Strategy in Cancer Therapy

Significance: This study innovates by systematically integrating the molecular mechanisms of iron death and its application in cancer therapy. By deeply analyzing the interaction between iron death and the tumor microenvironment, the study provides a new theoretical basis for cancer treatment and directions for developing more effective treatment strategies. In addition, the study points to critical issues and barriers that need to be addressed in future research, providing valuable insights into the use of iron death in clinical translation. Recent Advances: These findings are expected to drive further advances in cancer treatment, bringing patients more treatment options and hope. Through this paper, we see the great potential of iron death in cancer treatment and look forward to more research results being translated into clinical applications in the future to contribute to the fight against cancer. Critical Issues: In today's society, cancer is still one of the major diseases threatening human health. Despite advances in existing treatments, cancer recurrence and drug resistance remain a severe problem. These problems increase the difficulty of treatment and bring a substantial physical and mental burden to patients. Therefore, finding new treatment strategies to overcome these challenges has become significant. Future Directions: The study delved into the molecular basis of iron death in tumor biology. It proposed a conceptual framework to account for the interaction of iron death with the tumor immune microenvironment, guide treatment selection, predict efficacy, explore combination therapies, and identify new therapeutic targets to overcome cancer resistance to standard treatments, peeving a path for future research and clinical translation of ferroptosis as a potential strategy in cancer therapy. Antioxid. Redox Signal. 41, 616-636. [Figure: see text].

Ferroptosis: a new mechanism of traditional Chinese medicine for treating hematologic malignancies

Ferroptosis is a recently identified form of cell death characterized by lipid peroxidation and elevated iron levels. It is closely associated with hematologic malignancies, including leukemia, multiple myeloma (MM), and myelodysplastic syndromes (MDS). Research indicates that ferroptosis could represent a novel therapeutic target for these hematologic malignancies. Furthermore, traditional Chinese medicine (TCM) has been shown to modulate hematologic malignancies through the ferroptosis pathway. This paper aims to elucidate the mechanisms underlying ferroptosis and summarize the current research advancements regarding ferroptosis in hematologic malignancies, as well as the role of traditional Chinese medicine in the prevention and treatment of ferroptosis, with the goal of enhancing treatment efficacy.

Fingolimod alleviates type 2 diabetes associated cognitive decline by regulating autophagy and neuronal apoptosis via AMPK/mTOR pathway

This study aimed to reveal the role of fingolimod (FTY720) in mice with type 2 diabetes-associated cognitive decline and explore its potential neuroprotective mechanism. Mice were divided into five groups: normal control, normal control + FTY720 (1.0 mg/kg/day), type 2 diabetes mellitus, type 2 diabetes mellitus + low-dose FTY720 (0.5 mg/kg/day), and type 2 diabetes mellitus + high-dose FTY720 (1.0 mg/kg/day). Different doses of FTY720 were administered daily for 8 weeks after the induction of type 2 diabetes using a four-week high-fat diet feeding combined with continuous low-dose intraperitoneal injections of streptozotocin. After 8 weeks of treatment, the body weights and fasting blood glucose levels of mice from the five groups were compared. Morris water maze and new object recognition tests were used to evaluate cognitive function. Pathological changes in the hippocampal CA1 region were observed using haematoxylin-eosin and Nissl staining, and the ultrastructure of the hippocampal neurones was assessed using transmission electron microscopy. The expression levels of autophagy- and apoptosis-related proteins, such as LC3, Beclin-1, P62, Bax, and Bcl-2, in the mice hippocampus were detected by western blotting. Simultaneously, AMPK/mTOR signaling pathway proteins were detected to understand the potential mechanism. FTY720 had no significant effect on the body weight or fasting blood glucose levels in mice with type 2 diabetes. However, both FTY720 doses improved the cognitive function and hippocampal damage. In addition, the results suggested that FTY720 dramatically decreased P62 and Bax levels and increased LC3 II/LC3 I ratio, Beclin-1, and Bcl-2 expression in the hippocampus of type 2 diabetic mice. FTY720 also affected the expression of the AMPK/mTOR signaling pathway. Thus, FTY720 improved cognitive function and hippocampal pathological changes in type 2 diabetic mice without affecting fasting blood glucose levels. Our results show that FTY720 may exert neuroprotective effects in vivo by enhancing hippocampal autophagy and inhibiting apoptosis via the AMPK/mTOR signaling pathway.

A promising new approach to cancer therapy: Manipulate ferroptosis by hijacking endogenous iron

Ferroptosis, a form of regulated cell death characterized by iron-dependent phospholipid peroxidation, has emerged as a focal point in the field of cancer therapy. Compared with other cell death modes such as apoptosis and necrosis, ferroptosis exhibits many distinct characteristics in the molecular mechanisms and cell morphology, offering a promising avenue for combating cancers that are resistant to conventional therapeutic modalities. In light of the serious side effects associated with current Fenton-modulating ferroptosis therapies utilizing exogenous iron-based inorganic nanomaterials, hijacking endogenous iron could serve as an effective alternative strategy to trigger ferroptosis through targeting cellular iron regulatory mechanisms. A better understanding of the underlying iron regulatory mechanism in the process of ferroptosis has shed light on the current findings of endogenous ferroptosis-based nanomedicine strategies for cancer therapy. Here in this review article, we provide a comprehensive discussion on the regulatory network of iron metabolism and its pivotal role in ferroptosis, and present recent updates on the application of nanoparticles endowed with the ability to hijack endogenous iron for ferroptosis. We envision that the insights in the study may expedite the development and translation of endogenous ferroptosis-based nanomedicines for effective cancer treatment.

Multidimensional role of adapalene in regulating cell death in multiple myeloma

Aims

Multiple myeloma (MM) remains a challenging condition to cure, with persistent drug resistance negating the benefits of treatment advancements. The unraveling complexities in programmed cell death (PCD), inclusive of apoptosis, autophagy, and ferroptosis, have highlighted novel therapeutic avenues. Our study focuses on deciphering how adapalene (ADA), a small molecule compound, accelerates the demise of MM cells via targeting their compensatory survival mechanisms.

Methods

To assess the impact of ADA on MM, we employed flow cytometry and trypan blue exclusion assays to determine cell viabilities across MM cell lines and primary patient samples post-treatment. To delineate ADA's therapeutic targets and mechanisms, we conducted RNA sequencing (RNA-seq), gene set enrichment analysis (GSEA), molecular docking, and molecular dynamics simulations. We further designed pre-clinical trials emphasizing MM, exploring the efficacy of ADA as a standalone and in combination with bortezomib (BTZ).

Results

ADA elicited a dose-responsive induction of MM cell death. Building upon ADA's anti-MM capabilities as a single agent, we proposed that ADA-BTZ co-treatment might amplify this lethality. Indeed, ADA and BTZ together greatly potentiated MM cell death. ADA proved beneficial in restoring BTZ susceptibility in BTZ-resistant relapsed or refractory MM (RRMM) patient cells. Molecular simulations highlighted ADA's high affinity (-9.17 kcal/mol) for CD138, with MM-GBSA revealing a binding free energy of -27.39 kcal/mol. Detailed interaction analyses indicated hydrogen-bonding of ADA with CD138 at the Asp35 and Gln34 residues. Additionally, ADA emerged as a versatile instigator of both ferroptosis and apoptosis in MM cells. Furthermore, ADA disrupted activation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway triggered by BTZ, fostering cell death in BTZ-resistant MM subsets.

Conclusion

ADA demonstrates a comprehensive capability to orchestrate MM cell death, exerting pronounced anti-MM activity while disrupting NF-κB-related drug resistance. ADA sensitization of MM cells to BTZ unravels its potential as a novel therapeutic drug for MM management.

All Roads Lead to Rome: Comparing Nanoparticle- and Small Molecule-Driven Cell Autophagy

Autophagy, vital for removing cellular waste, is triggered differently by small molecules and nanoparticles. Small molecules, like rapamycin, non-selectively activate autophagy by inhibiting the mTOR pathway, which is essential for cell regulation. This can clear damaged components but may cause cytotoxicity with prolonged use. Nanoparticles, however, induce autophagy, often causing oxidative stress, through broader cellular interactions and can lead to a targeted form known as "xenophagy." Their impact varies with their properties but can be harnessed therapeutically. In this review, the autophagy induced by nanoparticles is explored and small molecules across four dimensions: the mechanisms behind autophagy induction, the outcomes of such induction, the toxicological effects on cellular autophagy, and the therapeutic potential of employing autophagy triggered by nanoparticles or small molecules. Although small molecules and nanoparticles each induce autophagy through different pathways and lead to diverse effects, both represent invaluable tools in cell biology, nanomedicine, and drug discovery, offering unique insights and therapeutic opportunities.

AP-1 inhibitor induces ferroptosis via the PI3K/AKT pathway in multiple myeloma cells

Multiple myeloma (MM) is an incurable malignancy of plasma cells that is sensitive to T-5224, an AP-1 inhibitor. Previous study indicated that T-5224 inhibits proliferation and induces apoptosis in MM cells. However, the high mortality cannot be fully explained. To date, no studies have investigated ferroptosis induced by T-5224 in MM. Therefore, we further investigated the mechanism by which T-5224 kills MM cells. We observed that T-5224 exhibits antimyeloma properties both in vitro and in vivo. T-5224-induced MM cell death was reversed by the ferroptosis-specific inhibitor ferropstatin-1 (Fer-1). The protein levels of the key ferroptosis regulators GPX4 and SLC7A11 were decreased by T-5224 in MM cells. Furthermore, T-5224 reduced the phosphorylation of PI3K and AKT signaling pathway components, ultimately causing MM cell death. Using 740 Y-P, a PI3K activator, and Fer-1, a ferroptosis inhibitor, we discovered that T-5224 induces ferroptosis through the PI3K/AKT pathway. Bortezomib (BTZ), an FDA-approved drug for MM treatment, can be administered in combination with other agents. We evaluated the synergistic effect of BTZ combined with AP-1 inhibitors on MM in vivo. Our findings provide a better theoretical basis for the potential mechanism of T-5224 and a new perspective on MM treatment.

Novel methyltransferase G9a inhibitor induces ferroptosis in multiple myeloma through Nrf2/HO-1 pathway

Multiple myeloma (MM) is a common malignant hematologic neoplasm, and the involvement of epigenetic modifications in its development and drug resistance has received widespread attention. Ferroptosis, a new ferroptosis-dependent programmed death mode, is closely associated with the development of MM. The novel methyltransferase inhibitor DCG066 has higher cell activity, but its mechanism of action in MM has not been clarified. Here, we found that DCG066 (5µM) inhibited the proliferation and induced ferroptosis in MM cells; the intracellular levels of ROS, iron, and MDA were significantly elevated, and the level of GSH was reduced after the treatment of DCG066; The protein expression levels of SLC7A11, GPX4, Nrf2 and HO-1 were significantly reduced, and these phenomena could be reversed by ferroptosis inhibitor Ferrostatin-1 (Fer-1) and Nrf2 activator Tert-butyl hydroquinone (TBHQ). Meanwhile, the protein expression levels of Keap1 was increased, and heat shock proteins (HSP70, HSP90 and HSPB1) were reduced after DCG066 treatment. In conclusion, this study confirmed that DCG066 inhibits MM proliferation and induces ferroptosis via the Nrf2/HO-1 pathway.

Targeting ferroptosis in neuroimmune and neurodegenerative disorders for the development of novel therapeutics

Neuroimmune and neurodegenerative ailments impose a substantial societal burden. Neuroimmune disorders involve the intricate regulatory interactions between the immune system and the central nervous system. Prominent examples of neuroimmune disorders encompass multiple sclerosis and neuromyelitis optica. Neurodegenerative diseases result from neuronal degeneration or demyelination in the brain or spinal cord, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. The precise underlying pathogenesis of these conditions remains incompletely understood. Ferroptosis, a programmed form of cell death characterised by lipid peroxidation and iron overload, plays a pivotal role in neuroimmune and neurodegenerative diseases. In this review, we provide a detailed overview of ferroptosis, its mechanisms, pathways, and regulation during the progression of neuroimmune and neurodegenerative diseases. Furthermore, we summarise the impact of ferroptosis on neuroimmune-related cells (T cells, B cells, neutrophils, and macrophages) and neural cells (glial cells and neurons). Finally, we explore the potential therapeutic implications of ferroptosis inhibitors in diverse neuroimmune and neurodegenerative diseases.

Naringenin enhances the efficacy of ferroptosis inducers by attenuating aerobic glycolysis by activating the AMPK-PGC1α signalling axis in liver cancer

Liver cancer is a heterogeneous disease characterized by poor responses to standard therapies and therefore unfavourable clinical outcomes. Understanding the characteristics of liver cancer and developing novel therapeutic strategies are imperative. Ferroptosis, a type of programmed cell death induced by lipid peroxidation, has emerged as a potential target for treatment. Naringenin, a natural compound that modulates lipid metabolism by targeting AMPK, shows promise in enhancing the efficacy of ferroptosis inducers. In this study, we utilized liver cancer cell lines and xenograft mice to explore the synergistic effects of naringenin in combination with ferroptosis inducers, examining both phenotypic outcomes and molecular mechanisms. Our study results indicate that the use of naringenin at non-toxic doses to hepatocytes can significantly enhance the anticancer effects of ferroptosis inducers (erastin, RSL3, and sorafenib). The combination index method confirmed a synergistic effect between naringenin and ferroptosis inducers. In comparison to naringenin or ferroptosis inducers alone, the combined therapy caused more robust lipid peroxidation and hence more severe ferroptotic damage to cancer cells. The inhibition of aerobic glycolysis mediated by the AMPK-PGC1α signalling axis is the key to naringenin's effect on reducing ferroptosis resistance in liver cancer, and the synergistic cytotoxic effect of naringenin and ferroptosis inducers on cancer cells was reversed after pretreatment with an AMPK inhibitor or a PGC1α inhibitor. Taken together, these findings suggest that naringenin could boost cancer cell sensitivity to ferroptosis inducers, which has potential clinical translational value.

Protein phosphatase 2A modulation and connection with miRNAs and natural products

Protein phosphatase 2A (PP2A), a heterotrimeric holoenzyme (scaffolding, catalytic, and regulatory subunits), regulates dephosphorylation for more than half of serine/threonine phosphosites and exhibits diverse cellular functions. Although several studies on natural products and miRNAs have emphasized their impacts on PP2A regulation, their connections lack systemic organization. Moreover, only part of the PP2A family has been investigated. This review focuses on the PP2A-modulating effects of natural products and miRNAs' interactions with potential PP2A targets in cancer and non-cancer cells. PP2A-modulating natural products and miRNAs were retrieved through a literature search. Utilizing the miRDB database, potential PP2A targets of these PP2A-modulating miRNAs for the whole set (17 members) of the PP2A family were retrieved. Finally, PP2A-modulating natural products and miRNAs were linked via a literature search. This review provides systemic directions for assessing natural products and miRNAs relating to the PP2A-modulating functions in cancer and disease treatments.

International consensus guidelines for the definition, detection, and interpretation of autophagy-dependent ferroptosis

Macroautophagy/autophagy is a complex degradation process with a dual role in cell death that is influenced by the cell types that are involved and the stressors they are exposed to. Ferroptosis is an iron-dependent oxidative form of cell death characterized by unrestricted lipid peroxidation in the context of heterogeneous and plastic mechanisms. Recent studies have shed light on the involvement of specific types of autophagy (e.g. ferritinophagy, lipophagy, and clockophagy) in initiating or executing ferroptotic cell death through the selective degradation of anti-injury proteins or organelles. Conversely, other forms of selective autophagy (e.g. reticulophagy and lysophagy) enhance the cellular defense against ferroptotic damage. Dysregulated autophagy-dependent ferroptosis has implications for a diverse range of pathological conditions. This review aims to present an updated definition of autophagy-dependent ferroptosis, discuss influential substrates and receptors, outline experimental methods, and propose guidelines for interpreting the results.Abbreviation: 3-MA:3-methyladenine; 4HNE: 4-hydroxynonenal; ACD: accidentalcell death; ADF: autophagy-dependentferroptosis; ARE: antioxidant response element; BH2:dihydrobiopterin; BH4: tetrahydrobiopterin; BMDMs: bonemarrow-derived macrophages; CMA: chaperone-mediated autophagy; CQ:chloroquine; DAMPs: danger/damage-associated molecular patterns; EMT,epithelial-mesenchymal transition; EPR: electronparamagnetic resonance; ER, endoplasmic reticulum; FRET: Försterresonance energy transfer; GFP: green fluorescent protein;GSH: glutathione;IF: immunofluorescence; IHC: immunohistochemistry; IOP, intraocularpressure; IRI: ischemia-reperfusion injury; LAA: linoleamide alkyne;MDA: malondialdehyde; PGSK: Phen Green™ SK;RCD: regulatedcell death; PUFAs: polyunsaturated fatty acids; RFP: red fluorescentprotein;ROS: reactive oxygen species; TBA: thiobarbituricacid; TBARS: thiobarbituric acid reactive substances; TEM:transmission electron microscopy.

Targeting regulated cell death (RCD) in hematological malignancies: Recent advances and therapeutic potential

Regulated cell death (RCD) is a form of cell death that can be regulated by numerous biomacromolecules. Accumulating evidence suggests that dysregulated expression and altered localization of related proteins in RCD promote the development of cancer. Targeting subroutines of RCD with pharmacological small-molecule compounds is becoming a promising therapeutic avenue for anti-tumor treatment, especially in hematological malignancies. Herein, we summarize the aberrant mechanisms of apoptosis, necroptosis, pyroptosis, PANoptosis, and ferroptosis in hematological malignancies. In particular, we focus on the relationship between cell death and tumorigenesis, anti-tumor immunotherapy, and drug resistance in hematological malignancies. Furthermore, we discuss the emerging therapeutic strategies targeting different RCD subroutines. This review aims to summarize the significance and potential mechanisms of RCD in hematological malignancies, along with the development and utilization of pertinent therapeutic strategies.

Bone marrow stromal cells dictate lanosterol biosynthesis and ferroptosis of multiple myeloma

Ferroptosis has been demonstrated a promising way to counteract chemoresistance of multiple myeloma (MM), however, roles and mechanism of bone marrow stromal cells (BMSCs) in regulating ferroptosis of MM cells remain elusive. Here, we uncovered that MM cells were more susceptible to ferroptotic induction under the interaction of BMSCs using in vitro and in vivo models. Mechanistically, BMSCs elevated the iron level in MM cells, thereby activating the steroid biosynthesis pathway, especially the production of lanosterol, a major source of reactive oxygen species (ROS) in MM cells. We discovered that direct coupling of CD40 ligand and CD40 receptor constituted the key signaling pathway governing lanosterol biosynthesis, and disruption of CD40/CD40L interaction using an anti-CD40 neutralizing antibody or conditional depletion of Cd40l in BMSCs successfully eliminated the iron level and lanosterol production of MM cells localized in the Vk*MYC Vk12653 or NSG mouse models. Our study deciphers the mechanism of BMSCs dictating ferroptosis of MM cells and highlights the therapeutic potential of non-apoptosis strategies for managing refractory or relapsed MM patients.

Targeting ferroptosis for leukemia therapy: exploring novel strategies from its mechanisms and role in leukemia based on nanotechnology

The latest findings in iron metabolism and the newly uncovered process of ferroptosis have paved the way for new potential strategies in anti-leukemia treatments. In the current project, we reviewed and summarized the current role of nanomedicine in the treatment and diagnosis of leukemia through a comparison made between traditional approaches applied in the treatment and diagnosis of leukemia via the existing investigations about the ferroptosis molecular mechanisms involved in various anti-tumor treatments. The application of nanotechnology and other novel technologies may provide a new direction in ferroptosis-driven leukemia therapies. The article explores the potential of targeting ferroptosis, a new form of regulated cell death, as a new therapeutic strategy for leukemia. It discusses the mechanisms of ferroptosis and its role in leukemia and how nanotechnology can enhance the delivery and efficacy of ferroptosis-inducing agents. The article not only highlights the promise of ferroptosis-targeted therapies and nanotechnology in revolutionizing leukemia treatment, but also calls for further research to overcome challenges and fully realize the clinical potential of this innovative approach. Finally, it discusses the challenges and opportunities in clinical applications of ferroptosis.

Multiple myeloma with high expression of SLC7A11 is sensitive to erastin-induced ferroptosis

Ferroptosis, a nonapoptotic form of cell death marked by iron-dependent peroxidation of phospholipids, is associated with the occurrence and progression of tumors. Erastin, a selective inhibitor of the cystine/glutamate transporter system Xc-, can induce the ferroptosis of cancer cells. Multiple myeloma (MM) has been reported to be insensitive to erastin-induced ferroptosis. However, we found the erastin sensitivity of different MM cells varied widely. Specifically, SLC7A11 abundance determined the sensitivity of MM cells to erastin-induced ferroptosis. MM cells expressing a high SLC7A11 level were more sensitive to erastin-induced ferroptosis than cells expressing a low level of SLC7A11. Moreover, the expression of SLC7A11 gradually increased with the progression of plasma cell dyscrasias. Survival analysis indicated that high levels of SLC7A11 predicted a poor prognosis for MM patients. Knocking down SLC7A11 expression significantly inhibited the proliferation of MM cells and induced ferroptotic cell death. Additionally, we revealed that the long noncoding RNA (lncRNA) SLC7A11-AS1 was a critical regulatory factor of SLC7A11 expression. SLC7A11-AS1 overexpression diminished SLC7A11 levels, leading to the ferroptosis of MM cells. In summary, our data show that heterogeneous SLC7A11 expression affects MM cell sensitivity to ferroptosis, providing a theoretical basis for improving the clinical treatment of MM.

Ferroptosis mechanisms and regulations in cardiovascular diseases in the past, present, and future

Cardiovascular diseases (CVDs) are the main diseases that endanger human health, and their risk factors contribute to high morbidity and a high rate of hospitalization. Cell death is the most important pathophysiology in CVDs. As one of the cell death mechanisms, ferroptosis is a new form of regulated cell death (RCD) that broadly participates in CVDs (such as myocardial infarction, heart transplantation, atherosclerosis, heart failure, ischaemia/reperfusion (I/R) injury, atrial fibrillation, cardiomyopathy (radiation-induced cardiomyopathy, diabetes cardiomyopathy, sepsis-induced cardiac injury, doxorubicin-induced cardiac injury, iron overload cardiomyopathy, and hypertrophic cardiomyopathy), and pulmonary arterial hypertension), involving in iron regulation, metabolic mechanism and lipid peroxidation. This article reviews recent research on the mechanism and regulation of ferroptosis and its relationship with the occurrence and treatment of CVDs, aiming to provide new ideas and treatment targets for the clinical diagnosis and treatment of CVDs by clarifying the latest progress in CVDs research.

NMDARs activation regulates endothelial ferroptosis via the PP2A-AMPK-HMGB1 axis

N-methyl-D-aspartate receptors (NMDARs) are ligand-gated, voltage-dependent channels of the ionotropic glutamate receptor family. The present study explored whether NMDAR activation induced ferroptosis in vascular endothelial cells and its complicated mechanisms in vivo and in vitro. Various detection approaches were used to determine the ferroptosis-related cellular iron content, lipid reactive oxygen species (LOS), siRNA molecules, RNA-sequence, MDA, GSH, and western blotting. The AMPK activator Acadesine (AICAR), HMGB1 inhibitor glycyrrhizin (GLY), PP2A inhibitor LB-100, and NMDAR inhibitor MK801 were used to investigate the involved in vivo and in vitro pathways. The activation of NMDAR with L-glutamic acid (GLU) or NMDA significantly promoted cellular ferroptosis, iron content, MDA, and the PTGS2 expression, while decreasing GPX4 expression and GSH concentration in human umbilical vein endothelial cells (HUVECs), which was reversed by ferroptosis inhibitors Ferrostatin-1(Fer-1), Liproxstatin-1 (Lip-1), or Deferoxamine (DFO). RNA-seq revealed that ferroptosis and SLC7A11 participate in NMDA or GLU-mediated NMDAR activation. The PP2A-AMPK-HMGB1 pathway was majorly associated with NMDAR activation-induced ferroptosis, validated using the PP2A inhibitor LB-100, AMPK activator AICAR, or HMGB1 siRNA. The role of NMDAR in ferroptosis was validated in HUVECs induced with the ferroptosis activator errasin or RSL3 and counteracted by the NMDAR inhibitor MK-801. The in vivo results showed that NMDA- or GLU-induced ferroptosis and LOS production was reversed by MK-801, LB-100, AICAR, MK-801, and GLY, confirming that the PP2A-AMPK-HMGB1 pathway is involved in NMDAR activation-induced vascular endothelium ferroptosis. In conclusion, the present study demonstrated a novel role of NMDAR in endothelial cell injury by regulating ferroptosis via the PP2A-AMPK-HMGB1 pathway.

Altering phosphorylation in cancer through PP2A modifiers

Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase integral to the regulation of many cellular processes. Due to the deregulation of PP2A in cancer, many of these processes are turned toward promoting tumor progression. Considerable research has been undertaken to discover molecules capable of modulating PP2A activity in cancer. Because PP2A is capable of immense substrate specificity across many cellular processes, the therapeutic targeting of PP2A in cancer can be completed through either enzyme inhibitors or activators. PP2A modulators likewise tend to be effective in drug-resistant cancers and work synergistically with other known cancer therapeutics. In this review, we will discuss the patterns of PP2A deregulation in cancer, and its known downstream signaling pathways important for cancer regulation, along with many activators and inhibitors of PP2A known to inhibit cancer progression.

Potential applications of ferroptosis inducers and regulatory molecules in hematological malignancy therapy

Ferroptosis, a novel form of iron-dependent cell death, has emerged as a potential avenue for promoting tumor cell death by causing cell membrane rupture and the accumulation of lipid peroxides (LPO) in the cell. Since its discovery in 2012, extensive research has been conducted to explore the mechanism of ferroptosis inducers, including erastin, sulfasalazine, and sorafenib. These compounds inhibit system XC-, while Ras-selective lethal small molecule 3 (RSL3) and FION2 specifically target GPX4 to promote ferroptosis. Therefore, targeting ferroptosis presents a promising therapeutic approach for malignant tumors. While the study of ferroptosis in solid tumors has made significant progress, there is limited information available on its role in hematological tumors. This review aims to summarize the molecular mechanisms of ferroptosis inducers and discuss their clinical applications in hematological malignancies. Furthermore, the identification of non-coding RNAs (ncRNAs) and genes that regulate key molecules in the ferroptosis pathway could provide new targets and establish a molecular theoretical foundation for exploring novel ferroptosis inducers in hematological malignancies.

Classical swine fever virus NS5A protein activates autophagy via the PP2A-DAPK3-Beclin 1 axis

IMPORTANCE

Autophagy is a conserved degradation process that maintains cellular homeostasis and regulates native and adaptive immunity. Viruses have evolved diverse strategies to inhibit or activate autophagy for their benefit. The paper reveals that CSFV NS5A mediates the dissociation of PP2A from Beclin 1 and the association of PP2A with DAPK3 by interaction with PPP2R1A and DAPK3, PP2A dephosphorylates DAPK3 to activate its protein kinase activity, and activated DAPK3 phosphorylates Beclin 1 to trigger autophagy, indicating that NS5A activates autophagy via the PP2A-DAPK3-Beclin 1 axis. These data highlight a novel mechanism by which CSFV activates autophagy to favor its replication, thereby contributing to the development of antiviral strategies.

Ferroptosis regulation by methylation in cancer

Epigenetic regulation plays a critical role in cancer development and progression. Methylation is an important epigenetic modification that influences gene expression by adding a methyl group to nucleic acids and proteins. Ferroptosis is a new form of regulated cell death triggered by the accumulation of iron and lipid peroxidation. Emerging evidence have shown that methylation regulation plays a significant role in the regulation of ferroptosis in cancer. This review aims to explore the methylation regulation of ferroptosis in cancer, including reactive oxygen species and iron bio-logical activity, amino acid and lipid metabolism, and drugs interaction. The findings of this review may provide new insights and strategies for the prevention and treatment of cancer.

The Emerging Roles of Ferroptosis in Pathophysiology and Treatment of Acute Lung Injury

Ferroptosis, a programmed cell death discovered in recent years, is an iron-dependent lipid peroxidation accumulation. Unlike other modes of cell death (autophagy, necroptosis, pyroptosis, cuproptosis, etc.), ferroptosis has unique morphological characteristics and plays an important role in a variety of diseases. In recent years, there has been great progress in the study of ferroptosis. Studies have found that ferroptosis is associated with acute lung injury (ALI), a condition with a high mortality rate and limited treatment options. This paper summarizes the mechanism of ferroptosis from the perspectives of iron metabolism, lipid metabolism, amino acid metabolism, and glutathione metabolism. It also discusses the research progress of ferroptosis in ALI in order to find new directions for the prevention and treatment of this condition.

Comprehensive analysis of ferroptosis-related genes in immune infiltration and prognosis in multiple myeloma

Background: One particular type of cellular death that is known as ferroptosis is caused by the excessive lipid peroxidation. It is a regulated form of cell death that can affect the response of the tumor cells. Currently, it is not known if the presence of this condition can affect the prognosis of patients with multiple myeloma (MM). Methods: In this study, we studied the expression differences and prognostic value of ferroptosis-related genes (FRGs) in MM, and established a ferroptosis risk scoring model. In order to improve the prediction accuracy and clinical applicability, a nomogram was also established. Through gene enrichment analysis, pathways closely related to high-risk groups were identified. We then explored the differences in risk stratification in drug sensitivity and immune patterns, and evaluated their value in prognostic prediction and treatment response. Lastly, we gathered MM cell lines and samples from patients to confirm the expression of marker FRGs using quantitative real-time PCR (qRT-PCR). Results: The ability to predict the survival of MM patients is a challenging issue. Through the use of a risk model derived from ferroptosis, we were able to develop a more accurate prediction of the disease's prognosis. They were then validated by a statistical analysis, which showed that the model is an independent factor in the prognosis of MM. Patients of high ferroptosis risk scores had a much worse chance of survival than those in the low-risk groups. The calibration and power of the nomogram were also strong. We noted that the link between the ferroptosis risk score and the clinical treatment was suggested by the FRG's significant correlation with the immune checkpoint genes and the medication sensitivity. We validated the predictive model using qRT-PCR. Conclusion: We demonstrated the association between FRGs and MM, and developed a new risk model for prognosis in MM patients. Our study sheds light on the potential clinical relevance of ferroptosis in MM and highlights its potential as a therapeutic target for patients with this disease.

Ferroptosis: a novel regulated cell death participating in cellular stress response, radiotherapy, and immunotherapy

BACKGROUND

Ferroptosis is a regulated cell death mode triggered by iron-dependent toxic membrane lipid peroxidation. As a novel cell death modality that is morphologically and mechanistically different from other forms of cell death, such as apoptosis and necrosis, ferroptosis has attracted extensive attention due to its association with various diseases. Evidence on ferroptosis as a potential therapeutic strategy has accumulated with the rapid growth of research on targeting ferroptosis for tumor suppression in recent years.

METHODS

We summarize the currently known characteristics and major regulatory mechanisms of ferroptosis and present the role of ferroptosis in cellular stress responses, including ER stress and autophagy. Furthermore, we elucidate the potential applications of ferroptosis in radiotherapy and immunotherapy, which will be beneficial in exploring new strategies for clinical tumor treatment.

RESULT AND CONCLUSION

Based on specific biomarkers and precise patient-specific assessment, targeting ferroptosis has great potential to be translated into practical new approaches for clinical cancer therapy, significantly contributing to the prevention, diagnosis, prognosis, and treatment of cancer.

Ginsenoside Rh4 inhibits the malignant progression of multiple myeloma and induces ferroptosis by regulating SIRT2

Multiple myeloma (MM) has a high mortality rate, and the exploration of therapeutic drugs for MM with low side effects is a hot topic at the moment. Ginsenoside Rh4 has been shown to inhibit tumour growth in many cancers. However, the role of ginsenoside Rh4 in MM and its reaction mechanism have not been reported so far. After the treatment with different concentrations of ginsenoside Rh4, the proliferation of NCI-H929 cells was detected by Cell Counting Kit-8 and 5-ethynyl-2'-deoxyuridine staining. The cell apoptosis and cycle arrest were detected by flow cytometry and western blot. The thiobarbituric acid-reactive substances (TBARS) production was assessed with TBARS assay, whereas Fe²⁺ fluorescence assay was used for the measurement of Fe²⁺ level. The production of reactive oxygen species was evaluated with dichloro-dihydro-fluorescein diacetate staining, and western blot was applied for the estimation of ferroptosis-related proteins. The potential targets of ginsenoside Rh4 were predicted by molecular docking technology and verified by western blot. The transfection efficacy of overexpression-SIRT2 was examined with quantitative reverse transcription polymerase chain reaction and western blot. To figure out the detailed reaction mechanism between ginsenoside Rh4 and SIRT2 in MM, rescue experiments were conducted. We found that ginsenoside Rh4 inhibited cell proliferation, induced cell apoptosis, promoted cycle arrest and facilitated ferroptosis in MM. Moreover, ginsenoside Rh4 inhibited SIRT2 expression in MM cells. The overexpression of SIRT2 reversed the effects of ginsenoside Rh4 on cell proliferation, cell apoptosis, cycle arrest and ferroptosis in MM. Overall, ginsenoside Rh4 inhibited the malignant progression of MM and induced ferroptosis by regulating SIRT2.

Ferroptosis in Haematological Malignancies and Associated Therapeutic Nanotechnologies

Haematological malignancies are heterogeneous groups of cancers of the bone marrow, blood or lymph nodes, and while therapeutic advances have greatly improved the lifespan and quality of life of those afflicted, many of these cancers remain incurable. The iron-dependent, lipid oxidation-mediated form of cell death, ferroptosis, has emerged as a promising pathway to induce cancer cell death, particularly in those malignancies that are resistant to traditional apoptosis-inducing therapies. Although promising findings have been published in several solid and haematological malignancies, the major drawbacks of ferroptosis-inducing therapies are efficient drug delivery and toxicities to healthy tissue. The development of tumour-targeting and precision medicines, particularly when combined with nanotechnologies, holds potential as a way in which to overcome these obstacles and progress ferroptosis-inducing therapies into the clinic. Here, we review the current state-of-play of ferroptosis in haematological malignancies as well as encouraging discoveries in the field of ferroptosis nanotechnologies. While the research into ferroptosis nanotechnologies in haematological malignancies is limited, its pre-clinical success in solid tumours suggests this is a very feasible therapeutic approach to treat blood cancers such as multiple myeloma, lymphoma and leukaemia.

Targeting ABCB6 with nitidine chloride inhibits PI3K/AKT signaling pathway to promote ferroptosis in multiple myeloma

Since multiple myeloma (MM) remains a cureless malignancy of plasma cells to date, it becomes imperative to develop novel drugs and therapeutic targets for MM. We screened a small molecule library comprising 3633 natural product drugs, which demonstrated that Nitidine Chloride (NC), an extract from traditional Chinese medicine Zanthoxylum nitidum. We used Surface Plasmon Resonance-High Performance Liquid Chromatography-Protein Mass Spectrometry (SPR-HPLC-MS), Cellular Thermal Shift Assay (CETSA), molecular docking, and SPR assay to identify the potential targets of NC, in which ABCB6 was the unique target of NC. The effects of ABCB6 on cellular proliferation and drug resistance were determined by CCK8, western blot, flow cytometry, site-mutation cells, transmission electron microscopy, immunohistochemistry staining and xenograft model in vitro and in vivo. NC induced MM cell death by promoting ferroptosis. ABCB6 is the direct target of NC. ABCB6 expression was increased in MM samples compared to normal controls, which was significantly associated with MM relapse and poor outcomes. VGSK was the inferred binding epitope of NC on the ABCB6 protein. In the ABCB6-mutated MM cells, NC did not display cancer resistance, implying the vital role of ABCB6 in NC's bioactivity. Moreover, the silencing of ABCB6 significantly inhibited MM cell growth. Mechanistically, the direct binding of NC to ABCB6 suppressed PI3K/AKT signaling pathway to promote ferroptosis. In conclusion, ABCB6 can be a potential therapeutic target and prognostic biomarker in MM, while NC can be considered a novel drug for MM treatment.

Regulation of ncRNAs involved with ferroptosis in various cancers

As a special pattern of programmed cell death, ferroptosis is reported to participate in several processes of tumor progression, including regulating proliferation, suppressing apoptotic pathways, increasing metastasis, and acquiring drug resistance. The marked features of ferroptosis are an abnormal intracellular iron metabolism and lipid peroxidation that are pluralistically modulated by ferroptosis-related molecules and signals, such as iron metabolism, lipid peroxidation, system Xc−, GPX4, ROS production, and Nrf2 signals. Non-coding RNAs (ncRNAs) are a type of functional RNA molecules that are not translated into a protein. Increasing studies demonstrate that ncRNAs have a diversity of regulatory roles in ferroptosis, thus influencing the progression of cancers. In this study, we review the fundamental mechanisms and regulation network of ncRNAs on ferroptosis in various tumors, aiming to provide a systematic understanding of recently emerging non-coding RNAs and ferroptosis.

Ursolic Acid Ameliorates Myocardial Ischaemia/Reperfusion Injury by Improving Mitochondrial Function via Immunoproteasome-PP2A-AMPK Signalling

Cardiac ischaemia/reperfusion (I/R) injury causes cardiomyocyte apoptosis and mitochondrial dysfunction. Ursolic acid (UA), as a pentacyclic triterpenoid carboxylic acid, exerts several bioactivities in animal models of different diseases, but the preventive role of UA in I/R-induced myocardial dysfunction remains largely unknown. Male wild-type mice were pre-administered with UA at a dosage of 80 mg/kg i.p. and then subjected to cardiac I/R injury for 24 h. Cardiac function and pathological changes were examined by echocardiography and histological staining. The protein and mRNA levels of the genes were determined using qPCR and immunoblotting analysis. Our results revealed that UA administration in mice significantly attenuated the I/R-induced decline in cardiac function, infarct size, myocyte apoptosis, and oxidative stress. Mechanistically, UA increased three immunoproteasome catalytic subunit expressions and activities, which promoted ubiquitinated PP2A degradation and activated AMPK-PGC1α signalling, leading to improved mitochondrial biosynthesis and dynamic balance. In vitro experiments confirmed that UA treatment prevented hypoxia/reperfusion (H/R)-induced cardiomyocyte apoptosis and mitochondrial dysfunction through activation of AMPK signalling. In summary, our findings identify UA as a new activator of the immunoproteasome that exerts a protective role in I/R-induced myocardial dysfunction and suggest that UA supplementation could be beneficial for the prevention of cardiac ischaemic disease.

Erastin induces ferroptosis in cervical cancer cells via Nrf2/HO-1 signaling pathway

OBJECTIVE

Our research aims to assess the influence of erastin, a ferroptosis-inducing agent, on cervical cancer cells.

INTRODUCTION

Cervical cancer is a prevalent malignancy in females. Dysregulation of ferroptosis, a form of cell demise reliant on iron, is implicated in several cancers.

METHODS

The effect of erastin on HeLa and SiHa was detected by transwell assay, scratch test, and colony formation assay, while cell apoptosis was detected using flow cytometry. Cellular reactive oxygen species (ROS) generation was detected using the dichloro-dihydro-fluorescein diacetate assay. Sequencing analysis identified differentially expressed genes (DEGs), and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) Enrichment analyses were employed to identify the target gene. Subsequently, the utilization of small interfering RNA (siRNA) was employed to suppress the targeted gene expression in HeLa cells, thereby effectively mitigating the impact of erastin on various cellular processes including invasion, colony formation, migration, and ROS generation.

RESULTS

The findings indicate that erastin attenuates the viability of both HeLa cells (IC50 = 30.88 µM) and SiHa cells (IC50 = 29.40 µM). Treatment with erastin at 10 µM inhibits the invasion, colony formation, and migration of both HeLa and SiHa cells within 24 h. Ferrostatin-1 (1 µM) notably alleviates the inhibitory effects of erastin of HeLa and SiHa cells. Upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream target, heme oxygenase-1 (HO-1), was found in erastin-treated cells compared to the control group. When knocked down HO-1 in HeLa cells, effectively counteracting the effects of erastin on the invasion, colony formation, migration, and ROS production in HeLa cells.

CONCLUSION

Our research demonstrates that erastin induces ferroptosis and the accumulation of ROS in cervical cancer cells by activating the Nrf2/HO-1 pathway, significantly reducing cell proliferation and motility. These findings propose a potential molecular mechanism of erastin-mediated cervical cancer development.

From iron chelation to overload as a therapeutic strategy to induce ferroptosis in hematologic malignancies

OBJECTIVES

Ferroptosis is an iron-dependent, non-apoptotic mode of cell death characterized by excessive accumulation of reactive oxygen species (ROS). It plays an important role in the occurrence, development and treatment of various cancers, but little is known regarding the role of ferroptosis in hematologic malignancies. This review elaborates the regulatory mechanism of ferroptosis and the treatment opportunities for targeting ferroptosis in hematologic malignancies.

METHODS

A systematic literature review through PubMed was conducted to summarize the published evidence on the therapeutic potential of targeting ferroptosis in hematological malignant tumors. Literature sources published in English were searched, using the terms ferroptosis, leukemia, myelodysplastic syndrome, lymphoma and multiple myeloma.

RESULTS

More and more small molecules have been found to induce ferroptosis in hematologic malignancies through targeted iron metabolism and lipid peroxidation, and some ferroptosis inducers have been proved to have synergistic effect with other chemotherapeutic drugs.

CONCLUSION

This paper discusses the significance of ferroptosis in hematologic malignancies and provides a new way for the treatment of hematologic malignancies, and more experimental studies should be conducted in future.

Shikonin induces ferroptosis in multiple myeloma via GOT1-mediated ferritinophagy

Multiple myeloma (MM) is an incurable hematological malignancy that lacks effective therapeutic interventions. Ferroptosis is a newly discovered form of cell death that has shown great potential for MM therapy. As a proteasome inhibitor and necroptosis inducer, shikonin (SHK) performs dual functions in MM cells. However, whether SHK inhibits the development of MM via ferroptosis or any other mechanism remains elusive. Here, we provide evidence that SHK treatment was capable of inducing ferroptosis and immunogenic cell death (ICD) in MM. The results showed that SHK treatment induced lactate dehydrogenase release, triggered cell death, evoked oxidative stress, and enhanced ferrous iron and lipid peroxidation levels. Furthermore, treatment with ferroptosis inhibitors reversed SHK-induced cell death, which indicated that ferroptosis contributed to this phenomenon. Meanwhile, ferroptosis was accompanied by the extracellular release of Adenosine 5'-triphosphate (ATP) and High mobility group protein B1 (HMGB1), which are characteristics of ICD. Further investigation showed that glutamic-oxaloacetic transaminase 1 (GOT1) acted as a critical mediator of SHK-induced ferroptosis by promoting ferritinophagy. In conclusion, our findings suggest that SHK exerts ferroptotic effects on MM by regulating GOT1-mediated ferritinophagy. Thus, SHK is a potential therapeutic agent for MM.

Pathological mechanisms and crosstalk among different forms of cell death in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disorder characterized by a profound immune dysregulation and the presence of a variety of autoantibodies. Aberrant activation of programmed cell death (PCD) signaling and accelerated cell death is critical in the immunopathogenesis of SLE. Accumulating cellular components from the dead cells and ineffective clearance of the dead cell debris, in particular the nucleic acids and nucleic acids-protein complexes, provide a stable source of self-antigens, which potently activate auto-reactive B cells and promote IFN-I responses in SLE. Different cell types display distinct susceptibility and characteristics to a certain type of cell death, while different PCDs in various cells have mutual and intricate connections to promote immune dysregulation and contribute to the development of SLE. In this review, we discuss the role of various cell death pathways and their interactions in the pathogenesis of SLE. An in depth understanding of the interconnections among various forms cell death in SLE will lead to a better understanding of disease pathogenesis, shedding light on the development of novel therapeutic targets.

Role of Sphingolipids in Multiple Myeloma Progression, Drug Resistance, and Their Potential as Therapeutic Targets

Multiple myeloma (MM) is an incapacitating hematological malignancy characterized by accumulation of cancerous plasma cells in the bone marrow (BM) and production of an abnormal monoclonal protein (M-protein). The BM microenvironment has a key role in myeloma development by facilitating the growth of the aberrant plasma cells, which eventually interfere with the homeostasis of the bone cells, exacerbating osteolysis and inhibiting osteoblast differentiation. Recent recognition that metabolic reprograming has a major role in tumor growth and adaptation to specific changes in the microenvironmental niche have led to consideration of the role of sphingolipids and the enzymes that control their biosynthesis and degradation as critical mediators of cancer since these bioactive lipids have been directly linked to the control of cell growth, proliferation, and apoptosis, among other cellular functions. In this review, we present the recent progress of the research investigating the biological implications of sphingolipid metabolism alterations in the regulation of myeloma development and its progression from the pre-malignant stage and discuss the roles of sphingolipids in in MM migration and adhesion, survival and proliferation, as well as angiogenesis and invasion. We introduce the current knowledge regarding the role of sphingolipids as mediators of the immune response and drug-resistance in MM and tackle the new developments suggesting the manipulation of the sphingolipid network as a novel therapeutic direction for MM.

Function and regulation of GPX4 in the development and progression of fibrotic disease

Fibrosis is a common feature of fibrotic diseases that poses a serious threat to global health due to high morbidity and mortality in developing countries. There exist some chemical compounds and biomolecules associated with the development of fibrosis, including cytokines, hormones, and enzymes. Among them, glutathione peroxidase 4 (GPX4), as a selenoprotein antioxidant enzyme, is widely found in the embryo, testis, brain, liver, heart, and photoreceptor cells. Moreover, it is shown that GPX4 elicits diverse biological functions by suppressing phospholipid hydroperoxide at the expense of decreased glutathione (GSH), including loss of neurons, autophagy, cell repair, inflammation, ferroptosis, apoptosis, and oxidative stress. Interestingly, these processes are intimately related to the occurrence of fibrotic disease. Recently, GPX4 has been reported to exhibit a decline in fibrotic disease and inhibit fibrosis, suggesting that alterations of GPX4 can change the course or dictate the outcome of fibrotic disease. In this review, we summarize the role and underlying mechanisms of GPX4 in fibrosis diseases such as lung fibrosis, liver fibrosis, kidney fibrosis, cardiac fibrosis, and myelofibrosis.

Lupeol triggers oxidative stress, ferroptosis, apoptosis and restrains inflammation in nasopharyngeal carcinoma via AMPK/NF-κB pathway

OBJECTIVE

Nasopharyngeal carcinoma is a malignant tumor with high incidence in Asia. This study investigated the anti-tumor capacities of lupeol in nasopharyngeal carcinoma.

METHODS

CCK-8 assay was employed to select the suitable concentration and intervention time of lupeol in 5-8F and CNE1 cells. The anti-cancer impacts of lupeol were evaluated by flow cytometry, ROS generation, western blotting, ELISA, iron assay, lipid peroxidation, mitochondrial membrane potential (MMP), TUNEL, and immunohistochemistry assays. Additionally, levels of AMPK/NF-κB pathway-related proteins were tested by western blotting.

RESULTS

Cell viability was notably decreased after administration of lupeol ≧ 20 μM. 20 μM and 40 μM lupeol induced cell apoptosis, enhanced oxidative stress and restrained immune response in nasopharyngeal carcinoma cells to some extent, as evidenced by the elevation of apoptotic rate, Bax and cleaved caspase-3 expression, ROS production and malondialdehyde level, and reduction of levels of Bcl-2, MMP, superoxide dismutase, TNF-α, IL-6 and IL-1β. Also, lupeol promoted the iron secretion and lipid peroxidation, the effects of which were reversed by ferroptosis inhibitor (Fer-1). The inhibitory impacts of lupeol at the doses of 20 μM and 40 μM on glutathione and GPX4 levels were observed. Importantly, lupeol significantly elevated AMPKα phosphorylation, and reduced the levels of p-IκBα and nuclear NF-κB p65. Rescue assay stated that siAMPK could neutralize the above impacts of lupeol. Moreover, lupeol suppressed tumorigenesis of xenografts in nude mice.

CONCLUSION

Lupeol exerted the anti-cancer impacts by inducing oxidative stress, ferroptosis and apoptosis, and suppressing inflammation via the AMPK/NF-κB pathway in nasopharyngeal carcinoma.

Targeting Sphingolipid Metabolism as a Therapeutic Strategy in Cancer Treatment

Sphingolipids are bioactive molecules that have key roles in regulating tumor cell death and survival through, in part, the functional roles of ceramide accumulation and sphingosine-1-phosphate (S1P) production, respectively. Mechanistic studies using cell lines, mouse models, or human tumors have revealed crucial roles of sphingolipid metabolic signaling in regulating tumor progression in response to anticancer therapy. Specifically, studies to understand ceramide and S1P production pathways with their downstream targets have provided novel therapeutic strategies for cancer treatment. In this review, we present recent evidence of the critical roles of sphingolipids and their metabolic enzymes in regulating tumor progression via mechanisms involving cell death or survival. The roles of S1P in enabling tumor growth/metastasis and conferring cancer resistance to existing therapeutics are also highlighted. Additionally, using the publicly available transcriptomic database, we assess the prognostic values of key sphingolipid enzymes on the overall survival of patients with different malignancies and present studies that highlight their clinical implications for anticancer treatment.

Maresin1 Protect Against Ferroptosis-Induced Liver Injury Through ROS Inhibition and Nrf2/HO-1/GPX4 Activation

Drugs, viruses, and chemical poisons stimulating live in a short period of time can cause acute liver injury (ALI). ALI can further develop into serious liver diseases such as cirrhosis and liver cancer. Therefore, how to effectively prevent and treat ALI has become the focus of research. Numerous studies have reported Maresin1 (MaR1) has anti-inflammatory effect and protective functions on organs. In the present study, we used d-galactosamine/lipopolysaccharide (D-GalN/LPS) to establish an ALI model, explored the mechanism of liver cells death caused by D-GalN/LPS, and determined the effect of MaR1 on D-GalN/LPS-induced ALI. In vivo experiments, we found that MaR1 and ferrostatin-1 significantly alleviated D-GalN/LPS-induced ALI, reduced serum alanine transaminase and aspartate transaminase levels, and improved the survival rate of mice. Meanwhile, MaR1 inhibited hepatocyte death, inhibited tissue reactive oxygen species (ROS) expression, reduced malondialdehyde (MDA), reduced glutathione (GSH), GSH/oxidized glutathione (GSSG), and iron content induced by D-GalN/LPS in mice. In addition, MaR1 inhibited ferroptosis-induced liver injury through inhibiting the release of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and IL-6. Subsequently, western blot showed that MaR1 improved the expression of nuclear factor E2-related factor 2(Nrf2)/heme oxygenase-1 (HO-1)/glutathione peroxidase 4 (GPX4). In vitro experiments, we found that MaR1 inhibited LPS-induced and erastin-induced cell viability reduction. Meanwhile, we found that MaR1 increased the MDA and GSH levels in cells. Western blot showed that MaR1 increased the expression level of Nrf2/HO-1/GPX4. Next, the Nrf2 was knocked down in HepG2 cells, and the results showed that the protective effect of MaR1 significantly decreased. Finally, flow cytometry revealed that MaR1 inhibited ROS production and apoptosis. Overall, our study showed MaR1 inhibited ferroptosis-induced liver injury by inhibiting ROS production and Nrf2/HO-1/GPX4 activation.

Ferroptosis in hematological malignancies and its potential network with abnormal tumor metabolism

Ferroptosis, a new type of regulated cell death, displays characteristics that transparently differ from apoptosis, autophagy and necroptosis. There is growing appreciation that targeting ferroptosis is potentially a novel strategy in anti-tumor therapy, especially for invasive malignancies demonstrating resistance to chemotherapy. Almost all types of cancer cells depend on abnormal metabolic activities to participate in vicious progression, giving the possibility to interfere with underlying metabolic preferences and compromise malignant cells by inducing ferroptosis. In this perspective, we give an overview of potential interactions between ferroptosis and abnormal tumor metabolism, with special focus on systematic researches in hematological malignancies.