Ferroptosis, a novel pharmacological mechanism of anti-cancer drugs

Isoorientin reverses lung cancer drug resistance by promoting ferroptosis via the SIRT6/Nrf2/GPX4 signaling pathway

Cisplatin, or DDP, is a highly successful and well-known chemotherapy drug used to treat cancer. Acquired resistance to chemotherapy is a major clinical concern, yet the mechanisms of this resistance are still unknown. Ferroptosis is a type of cell death distinct from other forms, fueled by a buildup of iron-associated lipid reactive oxygen species (ROS). Gaining insight into the process of ferroptosis could lead to novel treatments for overcoming cancer resistance. In this study, the combination of isoorientin (IO) and DDP treatment resulted in a significant decrease in the viability of drug-resistant cells, a substantial increase in intracellular iron, malondialdehyde (MDA) and ROS concentrations, a notable decrease in glutathione concentration, and the occurrence of ferroptosis in cells, as revealed by in vitro and in vivo experiments. Additionally, there was a decrease in the expression of nuclear factor-erythroid factor 2-related factor 2 (Nrf2), glutathione peroxidase 4 (GPX4), and sirtuin 6 (SIRT6) proteins, and an increase in cellular ferroptosis. Isoorientin acts as a mediator to regulate cellular ferroptosis and reverse drug resistance in lung cancer cells by controlling the SIRT6/Nrf2/GPX4 signaling pathway. The findings of this study suggest that IO can promote ferroptosis and reverse drug resistance in lung cancer through the SIRT6/Nrf2/GPX4 signaling pathway, thus offering a theoretical basis for its potential clinical application.

Piezoelectric enhanced sulfur doped graphdiyne nanozymes for synergistic ferroptosis-apoptosis anticancer therapy

Graphdiyne has excellent potential due to its enzymatic properties. Metal-free sulfur-doped Graphdiyne (S-GDY) has piezoelectric characteristics, and ultrasonic excitation of S-GDY enhances peroxidase activity. It can turn hydrogen peroxide into toxic hydroxyl radicals and induce apoptosis in 4T1 cells. More importantly, the ultrasound (US) enhanced nanozyme induced 4T1 cell ferroptosis by promoting an imbalanced redox reaction due to glutathione depletion and glutathione peroxidase 4 inactivation. S-GDY exhibited enhanced nanozyme activity in vitro and in vivo that may directly trigger apoptosis-ferroptosis for effective tumor therapy. Altogether, this study was expected to provide new insights into the design of piezoelectric catalytic nanozyme and expand their application in the catalytic therapy of tumors.

A Mitochondria-Targeted Ferroptosis Inducer Activated by Glutathione-Responsive Imaging and Depletion for Triple Negative Breast Cancer Theranostics

Ferroptosis is a new type of iron-dependent programmed cell death characterized by glutathione (GSH) depletion, selenoprotein glutathione peroxidase 4 (GPX4) inactivation, and lipid peroxides accumulation. Mitochondria, as the main source of intracellular energy supply and reactive oxygen species (ROS) generation, play a central role in oxidative phosphorylation and redox homeostasis. Therefore, targeting cancer-cell mitochondria and attacking redox homeostasis is expected to induce robust ferroptosis-mediated anticancer effects. In this work, a theranostic ferroptosis inducer (IR780-SPhF), which can simultaneously achieve the imaging and therapy of triple-negative breast cancer (TNBC) by targeting mitochondria is presented. It is developed from a mitochondria-targeting small molecule (IR780) with cancer-preferential accumulation, enabling it to react with GSH by nucleophilic substitution, resulting in mitochondrial GSH depletion and redox imbalance. More interestingly, IR780-SPhF exhibits GSH-responsive near-infrared fluorescence emission and photoacoustic imaging characteristics, further facilitating diagnosis and treatment with real-time monitoring of TNBC with a highly elevated GSH level. Both in vitro and in vivo results demonstrate that IR780-SPhF exhibits potent anticancer effect, which is significantly stronger than cyclophosphamide, a classic drug commonly recommended for TNBC patients in clinic. Hence, the reported mitochondria-targeted ferroptosis inducer may represent a promising candidate and a prospective strategy for efficient cancer treatment.

Effects of amygdalin on ferroptosis and oxidative stress in diabetic retinopathy progression via the NRF2/ARE signaling pathway

Oxidative stress has been involved in the pathogenesis of diabetic retinopathy (DR). Amygdalin is an effective component of bitter almond that exhibits excellent antioxidant properties. We explored the effects of amygdalin on ferroptosis and oxidative stress in high-glucose (HG)-stimulated human retinal endothelial cells (HRECs) via the NRF2/ARE pathway. HG-stimulated HRECs were used to establish a DR model. Cell viability was evaluated using the MTT assay. The release of lactate dehydrogenase was used to evaluate cell toxicity. The protein levels of NRF2, NQO1, and HO-1 were detected using western blotting. The GSH, GSSG, GPX4, SOD, CAT, MDA, and Fe2+ levels in the HRECs were also detected. Flow cytometry was used to detect reactive oxygen species (ROS) using a fluorescent probe. Immunofluorescence staining was performed to detect NRF2 expression. The results revealed that HG stimulation decreased the levels of GSH, GPX4, SOD, and CAT but increased those of MDA, ROS, GSSG, and Fe2+ in HRECs. Ferrostatin-1 treatment reversed the effects of HG stimulation, whereas erastin aggravated these effects. Amygdalin treatment relieved HG-induced injury in HRECs. Amygdalin treatment promoted the nuclear transport of NRF2 in HG-stimulated HRECs. NQO1 and HO-1 levels were upregulated in HG-stimulated HRECs after amygdalin treatment. An inhibitor of NRF2 reversed the effects of amygdalin. Therefore, amygdalin treatment inhibited ferroptosis and oxidative stress in HG-stimulated HRECs by activating the NRF2/ARE signaling pathway.

Preclinical models to understand the biology and to discover new targets in brain metastases

PURPOSE OF REVIEW

Incidence of brain metastases increases overtime therefore it is important to rapidly progress in the discovery of new strategies of treatment for these patients. In consequence, more and more preclinical models of brain metastases (BM) are established to study new treatments for melanoma, lung, and breast cancer BM. Here, we reviewed the most recent findings of new drugs assessed in BM mouse preclinical models.

RECENT FINDINGS

BM are a common metastatic site of several types of solid cancers and can be difficult to treat due to the unique environment of the brain and the blood-brain barrier. Currently, several preclinical models of BM have been demonstrated that new molecular targeted therapies, small metabolic inhibitors, immunotherapies or a combination of these drugs with radiotherapy lead to a reduction of BM growth and an improvement of mouse survival.

SUMMARY

The use of preclinical models of BM is crucial to discover new treatment strategies for patients with BM. In the last years, some new drugs have been highlighted in preclinical models and are now tested in clinical trials including patients with brain metastases.

Anticancer mechanisms on pyroptosis induced by Oridonin: New potential targeted therapeutic strategies

Pyroptosis is a type of inflammatory cell death that is triggered by the formation of pores on the cell membrane by gasdermin (GSDM) family proteins. This process activates inflammasomes and leads to the maturation and release of proinflammatory cytokines such as interleukin-1β (IL-1β) and interleukin-18 (IL-18). Pyroptosis, a form of programmed cell death, has been found to be associated with various biomolecules such as caspases, granzymes, non-coding RNA (lncRNA), reactive oxygen species (ROS), and NOD-like receptor protein 3 (NLRP3). These biomolecules have been shown to play a dual role in cancer by affecting cell proliferation, metastasis, and the tumor microenvironment (TME), resulting in both tumor promotion and anti-tumor effects. Recent studies have found that Oridonin (Ori) has anti-tumor effects by regulating pyroptosis through various pathways. Ori can inhibit pyroptosis by inhibiting caspase-1, which is responsible for activating pyroptosis of the canonical pathway. Additionally, Ori can inhibit pyroptosis by inhibiting NLRP3, which is responsible for activating pyroptosis of the noncanonical pathway. Interestingly, Ori can also activate pyroptosis by activating caspase-3 and caspase-8, which are responsible for activating pyroptosis of the emerging pathway; Ori has been found to be effective in inhibiting pyroptosis by blocking the action of perforin, which is responsible for facilitating the entry of granzyme into cells and activating pyroptosis. Additionally, Ori plays a crucial role in regulating pyroptosis by promoting the accumulation of ROS while inhibiting the ncRNA and NLRP3 pathways. It is worth noting that all of these pathways ultimately regulate pyroptosis by influencing the cleavage of GSDM, which is a key factor in the process. These studies concludes that Ori has extensive anti-cancer effects that are related to its potential regulatory function on pyroptosis. The paper summarizes several potential ways in which Ori participates in the regulation of pyroptosis, providing a reference for further study on the relationship between Ori, pyroptosis, and cancer.

Marine Alkaloid Lepadins E and H Induce Ferroptosis for Cancer Chemotherapy

Induction of ferroptosis emerges as an effective method for cancer treatment. With massive efforts to elucidate the ferroptosis mechanism, the development of new ferroptosis inducers proceeds rather slowly, with only a few small molecules identified. Herein, we report our discovery of marine alkaloid lepadins E and H as a new class of ferroptosis inducers. Our in vitro studies show that lepadins E and H exhibit significant cytotoxicity, promote p53 expression, increase ROS production and lipid peroxides, reduce SLC7A11 and GPX4 levels, and upregulate ACSL4 expression, all of which consistently support induction of ferroptosis through the classical p53-SLC7A11-GPX4 pathway. Our animal model study of lepadin H confirms its in vivo antitumor efficacy with negligible toxicity to normal organs. This work elucidates the mode of action of lepadins (E and H) and verifies their in vivo efficacy as a new class of ferroptosis inducers for anticancer therapy with translational potential.

Overexpressed transferrin receptor implied poor prognosis and relapse in gastrointestinal stromal tumors

Ferroptosis, as a novel-induced programmed cell death, plays critical roles in the pathogenesis of cancers. However, the promising biomarkers of ferroptosis in gastrointestinal stromal tumor (GIST) remain to be elucidated. Herein, the expression of ferroptosis-related genes was analyzed in GIST. Among the 64 ferroptosis-related genes, transferrin receptor (TFRC) expression presented a remarkable upregulation in high-risk patients through Gene Expression Omnibus (GEO) dataset analysis, as well as its significant change after imatinib was treated. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of TFRC-relevant genes revealed that TFRC expression was closely associated with cell growth pathways and metabolism-related pathways. Furthermore, patients at high risk of recurrence were more likely to exhibit high TFRC expression by immunohistochemistry. Additionally, high TFRC expression indicated an undesirable state of patient relapse, which could serve as a powerful significant independent predictor of recurrence-free survival (RFS). In summary, we systematically summarize the expression characteristics and clinical relevance of TFRC and show that TFRC can be used as a prognostic factor, which can be considered a potential therapeutic target in GIST.

Identification of hepatocellular carcinoma-related subtypes and development of a prognostic model: a study based on ferritinophagy-related genes

BACKGROUND

Hepatocellular carcinoma still has a high incidence and mortality rate worldwide, and further research is needed to investigate its occurrence and development mechanisms in depth in order to identify new therapeutic targets. Ferritinophagy is a type of autophagy and a key factor in ferroptosis that could influence tumor onset and progression. Although, the potential role of ferritinophagy-related genes (FRGs) in liver hepatocellular carcinoma (LIHC) is unknown.

METHODS

Single-cell RNA sequencing (scRNA-seq) data of LIHC were obtained from the Gene Expression Omnibus (GEO) dataset. In addition, transcriptome and clinical follow-up outcome data of individuals with LIHC were extracted from the The Cancer Genome Atlas (TCGA) dataset. FRGs were collected through the GeneCards database. Differential cell subpopulations were distinguished, and differentially expressed FRGs (DEFRGs) were obtained. Differential expression of FRGs and prognosis were observed according to the TCGA database. An FRG-related risk model was constructed to predict patient prognosis by absolute shrinkage and selection operator (LASSO) and COX regression analyses, and its prognosis predictive power was validated. Ultimately, the association between risk score and tumor microenvironment (TME), immune cell infiltration, immune checkpoints, drug sensitivity, and tumor mutation burden (TMB) was analyzed. We also used quantitative reverse transcription polymerase chain reaction (qRT-PCR) to validate the expression of key genes in normal liver cells and liver cancer cells.

RESULTS

We ultimately identified 8 cell types, and 7 differentially expressed FRGs genes (ZFP36, NCOA4, FTH1, FTL, TNF, PCBP1, CYB561A3) were found among immune cells, and we found that Monocytes and Macrophages were closely related to FRGs genes. Subsequently, COX regression analysis showed that patients with high expression of FTH1, FTL, and PCBP1 had significantly worse prognosis than those with low expression, and our survival prediction model, constructed based on age, stage, and risk score, showed better prognostic prediction ability. Our risk model based on 3 FRGs genes ultimately revealed significant differences between high-risk and low-risk groups in terms of immune infiltration and immune checkpoint correlation, drug sensitivity, and somatic mutation risk. Finally, we validated the key prognostic genes FTH1, FTL, using qRT-PCR, and found that the expression of FTH1 and FTL was significantly higher in various liver cancer cells than in normal liver cells. At the same time, immunohistochemistry showed that the expression of FTH1, FTL in tumor tissues was significantly higher than that in para-tumor tissues.

CONCLUSION

This study identifies a considerable impact of FRGs on immunity and prognosis in individuals with LIHC. The collective findings of this research provide new ideas for personalized treatment of LIHC and a more targeted therapy approach for individuals with LIHC to improve their prognosis.

BRAF Mutations in Melanoma: Biological Aspects, Therapeutic Implications, and Circulating Biomarkers

Melanoma is an aggressive form of skin cancer resulting from the malignant transformation of melanocytes. Recent therapeutic approaches, including targeted therapy and immunotherapy, have improved the prognosis and outcome of melanoma patients. BRAF is one of the most frequently mutated oncogenes recognised in melanoma. The most frequent oncogenic BRAF mutations consist of a single point mutation at codon 600 (mostly V600E) that leads to constitutive activation of the BRAF/MEK/ERK (MAPK) signalling pathway. Therefore, mutated BRAF has become a useful target for molecular therapy and the use of BRAF kinase inhibitors has shown promising results. However, several resistance mechanisms invariably develop leading to therapeutic failure. The aim of this manuscript is to review the role of BRAF mutational status in the pathogenesis of melanoma and its impact on differentiation and inflammation. Moreover, this review focuses on the mechanisms responsible for resistance to targeted therapies in BRAF-mutated melanoma and provides an overview of circulating biomarkers including circulating tumour cells, circulating tumour DNA, and non-coding RNAs.

MAT2A inhibits the ferroptosis in osteosarcoma progression regulated by miR-26b-5p

Osteosarcoma (OS) is the most frequent primary malignant bone tumor. Ferroptosis, a form of regulated cell death, is a key tumor suppression mechanism. Although methionine adenosyltransferase II alpha (MAT2A) has been reported to inhibit several tumor cells, it is unclear whether inhibition of MAT2A in OS cells can reduce ferroptosis. CCK-8, flow cytometry, and Transwell assays were performed to evaluate cell viability, cell apoptosis/cycle, and cell migration, respectively. The levels of ferrous iron and glutathione (GSH) levels in cells were measured to evaluate the degree of cell ferroptosis. Western blot analysis was performed to detect protein levels of MAT2A, p-STAT3 (Ser727)/STAT3, and solute carrier family 7 member 11 (SLC7A11) in OS cells. MAT2A was significantly upregulated in OS specimens and high MAT2A expression was associated with a poorer prognosis in OS patients. shRNA targeting MAT2A significantly increased OS cell apoptosis, triggered cell cycle arrest in the G2 phase, and attenuated migration ability in vitro. MAT2A depletion dramatically inhibited tumor progression of OS in vivo. Overexpression of MAT2A rescued the tumor inhibition caused by miR-26b-5p. MAT2A knockdown promoted OS cell ferroptosis. miR-26b-5p/MAT2A regulates tumor malignant progression and OS cell ferroptosis by controlling p-STAT3 and SLC7A11 expressions. Taken together, our study displayed that miR-26b-5p/MAT2A triggers ferroptosis in OS cells by increasing intracellular ferrous iron levels and inhibiting the STAT3/SLC7A11 axis. Our results reveal a MAT2A-mediated ferroptosis defense mechanism used by OS cells and propose a potential ferroptosis-inducing strategy for the treatment of OS patients.

Emerging roles of PHLPP phosphatases in lung cancer

Pleckstrin homologous domain leucine-rich repeating protein phosphatases (PHLPPs) were originally identified as protein kinase B (Akt) kinase hydrophobic motif specific phosphatases to maintain the cellular homeostasis. With the continuous expansion of PHLPPs research, imbalanced-PHLPPs were mainly found as a tumor suppressor gene of a variety of solid tumors. In this review, we simply described the history and structures of PHLPPs and summarized the recent achievements in emerging roles of PHLPPs in lung cancer by 1) the signaling pathways affected by PHLPPs including Phosphoinositide 3-kinase (PI3K)/AKT, RAS/RAF/mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) and Protein kinase C (PKC) signaling cascades. 2) function of PHLPPs regulatory factor USP46 and miR-190/miR-215, 3) the potential roles of PHLPPs in disease prognosis, Epidermal growth factor receptors (EGFR)- tyrosine kinase inhibitor (TKI) resistance and DNA damage, 4) and the possible function of PHLPPs in radiotherapy, ferroptosis and inflammation response. Therefore, PHLPPs can be considered as either biomarker or prognostic marker for lung cancer treatment.

Engineered Salmonella inhibits GPX4 expression and induces ferroptosis to suppress glioma growth in vitro and in vivo

PURPOSE

Glioma is a life-threatening malignancy where conventional therapies are ineffective. Bacterial cancer therapy has shown potential for glioma treatment, in particular, the facultative anaerobe Salmonella has been extensively studied. Meanwhile, ferroptosis is a newly characterized form of cell death. Nevertheless, the role of ferroptosis in Salmonella-induced tumour cell death remains unclear. Therefore, we aim to elucidate whether Salmonella YB1 exerts therapeutic effects via inducing ferroptosis in glioma.

METHODS

Following Salmonella YB1 infection, mRNA sequencing was applied to detect ferroptosis-related gene expression and the levels of reactive oxygen species, malondialdehyde, and glutathione were quantified. Transmission electron microscopy (TEM) was then used to observe the changes in the mitochondrial morphology of glioma cells. The role of ferroptosis in the anti-tumor effect of YB1 was assessed in vivo in mouse tumor xenograft models.

RESULTS

Whole-transcriptome analysis revealed that Salmonella YB1 infection alters ferroptosis-related gene expression in the U87 glioma cell line. Moreover, we found that Salmonella-induced ferroptosis is correlated with reduced levels of glutathione and glutathione peroxidase-4 (GPX4) and increased levels of reactive oxygen species and malondialdehyde in vitro. Meanwhile, TEM revealed that mitochondria are shrunken and mitochondrial membrane density increases in infected glioma cells. Experiments in vivo further showed that tumor growth in the Salmonella-treated group was significantly slower compared to the control and Fer-1 groups. However, Salmonella-induced tumor suppression can be reversed in vivo by Fer-1 treatment.

CONCLUSION

Salmonella YB1 inhibits GPX4 expression and induces ferroptosis to suppress glioma growth. Hence, ferroptosis regulation might represent a promising strategy to improve the efficacy of bacterial cancer therapy.

HNF4A-BAP31-VDAC1 axis synchronously regulates cell proliferation and ferroptosis in gastric cancer

B cell receptor associated protein 31 (BAP31) is closely associated with tumor progression, while the role and mechanism of BAP31 in gastric cancer (GC) remains unknown. This study explored that BAP31 was upregulated in GC tissues and high expression indicated poor survival of GC patients. BAP31 knockdown inhibited cell growth and induced G1/S arrest. Moreover, BAP31 attenuation increased the lipid peroxidation level of the membrane and facilitated cellular ferroptosis. Mechanistically, BAP31 regulated cell proliferation and ferroptosis by directly binding to VDAC1 and affected VDAC1 oligomerization and polyubiquitination. HNF4A was bound to BAP31 at the promoter and increased its transcription. Furthermore, knockdown of BAP31 inclined to make GC cells vulnerable to 5-FU and ferroptosis inducer, erastin, in vivo and in vitro. Our work suggests that BAP31 may serve as prognostic factor for gastric cancer and act as potential therapeutic strategy for gastric cancer.

Sculponeatin A promotes the ETS1-SYVN1 interaction to induce SLC7A11/xCT-dependent ferroptosis in breast cancer

BACKGROUND

E26 transformation specificity-1 (ETS1) is a transcription factor that is overexpressed in breast cancer (BC) and promotes tumor progression. Sculponeatin A (stA), a new diterpenoid extracted from Isodon sculponeatus, has no reported antitumor mechanism.

PURPOSE

Here, we explored the antitumor activity of stA in BC and further clarified its mechanism.

METHODS

Ferroptosis was detected by flow cytometric, glutathione, malondialdehyde, and iron determination assays. The effect of stA on the upstream signaling pathway of ferroptosis was detected by Western blot, gene expression, gene alterations and other approaches. The binding of stA and ETS1 was examined through a microscale thermophoresis assay and a drug affinity responsive target stability assay. An in vivo mouse model experiment was performed to evaluate the therapeutic and potential mechanism of stA.

RESULTS

stA exhibits therapeutic potential in BC by inducing SLC7A11/xCT-dependent ferroptosis. stA decreases the expression of ETS1, which is responsible for xCT-dependent ferroptosis in BC. stA inhibits the transcriptional expression of xCT by directly binding to the ETS domain of the ETS1 protein. In addition, stA promotes proteasomal degradation of ETS1 by triggering ubiquitin ligase synoviolin 1 (SYVN1)-mediated ubiquitination. The K318 site of ETS1 mediates ubiquitination of ETS1 by SYVN1. In a mouse model, stA inhibits tumor growth without causing obvious toxicity.

CONCLUSION

Taken together, the results confirm that stA promotes the ETS1-SYVN1 interaction to induce ferroptosis in BC mediated by ETS1 degradation. stA is expected to be used in research of candidate drugs for BC and drug design based on ETS1 degradation.

Cytoprotective Role of Heme Oxygenase-1 in Cancer Chemoresistance: Focus on Antioxidant, Antiapoptotic, and Pro-Autophagy Properties

Chemoresistance remains the foremost challenge in cancer therapy. Targeting reactive oxygen species (ROS) manipulation is a promising strategy in cancer treatment since tumor cells present high levels of intracellular ROS, which makes them more vulnerable to further ROS elevation than normal cells. Nevertheless, dynamic redox evolution and adaptation of tumor cells are capable of counteracting therapy-induced oxidative stress, which leads to chemoresistance. Hence, exploring the cytoprotective mechanisms of tumor cells is urgently needed to overcome chemoresistance. Heme oxygenase-1 (HO-1), a rate-limiting enzyme of heme degradation, acts as a crucial antioxidant defense and cytoprotective molecule in response to cellular stress. Recently, emerging evidence indicated that ROS detoxification and oxidative stress tolerance owing to the antioxidant function of HO-1 contribute to chemoresistance in various cancers. Enhanced HO-1 expression or enzymatic activity was revealed to promote apoptosis resistance and activate protective autophagy, which also involved in the development of chemoresistance. Moreover, inhibition of HO-1 in multiple cancers was identified to reversing chemoresistance or improving chemosensitivity. Here, we summarize the most recent advances regarding the antioxidant, antiapoptotic, and pro-autophagy properties of HO-1 in mediating chemoresistance, highlighting HO-1 as a novel target for overcoming chemoresistance and improving the prognosis of cancer patients.

Identification of essential sites of lipid peroxidation in ferroptosis

Ferroptosis, an iron-dependent form of cell death driven by lipid peroxidation, provides a potential treatment avenue for drug-resistant cancers and may play a role in the pathology of some degenerative diseases. Identifying the subcellular membranes essential for ferroptosis and the sequence of their peroxidation will illuminate drug discovery strategies and ferroptosis-relevant disease mechanisms. In this study, we employed fluorescence and stimulated Raman scattering imaging to examine the structure-activity-distribution relationship of ferroptosis-modulating compounds. We found that, although lipid peroxidation in various subcellular membranes can induce ferroptosis, the endoplasmic reticulum (ER) membrane is a key site of lipid peroxidation. Our results suggest an ordered progression model of membrane peroxidation during ferroptosis that accumulates initially in the ER membrane and later in the plasma membrane. Thus, the design of ER-targeted inhibitors and inducers of ferroptosis may be used to optimally control the dynamics of lipid peroxidation in cells undergoing ferroptosis.

Research progress on the mechanism of ferroptosis and its role in diabetic retinopathy

Ferroptosis is iron-dependent regulatory cell death (RCD). Morphologically, ferroptosis is manifested as mitochondrial atrophy and increased mitochondrial membrane density. Biochemically, ferroptosis is characterized by the depletion of glutathione (GSH), the inactivation of glutathione peroxidase 4 (GPX4), and an increase in lipid peroxides (LPO)and divalent iron ions. Ferroptosis is associated with various diseases, but the relationship with diabetic retinopathy(DR) is less studied. DR is one of the complications of diabetes mellitus and has a severe impact on visual function. The pathology of DR is complex, and the current treatment is unsatisfactory. Therefore, exploring pathogenesis is helpful for the clinical treatment of DR. This paper reviews the pathological mechanism of ferroptosis and DR in recent years and the involvement of ferroptosis in the pathology of DR. In addition, we propose problems that need to be addressed in this research field. It is expected to provide new ideas for treating DR by analyzing the role of ferroptosis in DR.

Ferroptosis: From regulation of lipid peroxidation to the treatment of diseases

Ferroptosis is a regulated cell death mainly manifested by iron-dependent lipid peroxide accumulation. The leading cause of ferroptosis is the imbalance of intracellular oxidative systems (e.g., LOXs, POR, ROS) and antioxidant systems (e.g., GSH/GPx4, CoQ10/FSP1, BH4/GCH1), which is regulated by a complex network. In the past decade, this metabolic network has been continuously refined, and the links with various pathophysiological processes have been gradually established. Apoptosis has been regarded as the only form of regulated cell death for a long time, and the application of chemotherapeutic drugs to induce apoptosis of cancer cells is the mainstream method. However, studies have reported that cancer cells' key features are resistance to apoptosis and chemotherapeutics. For high proliferation, cancer cells often have very active lipid metabolism and iron metabolism, which pave the way for ferroptosis. Interestingly, researchers found that drug-resistant or highly aggressive cancer cells are more prone to ferroptosis. Therefore, ferroptosis may be a potential strategy to eliminate cancer cells. In addition, links between ferroptosis and other diseases, such as neurological disorders and ischemia-reperfusion injury, have also been found. Understanding these diseases from the perspective of ferroptosis may provide new insights into clinical treatment. Herein, the metabolic processes in ferroptosis are reviewed, and the potential mechanisms and targets of ferroptosis in different diseases are summarized.

PRMT5 reduces immunotherapy efficacy in triple-negative breast cancer by methylating KEAP1 and inhibiting ferroptosis

BACKGROUND

As an emerging treatment strategy for triple-negative breast cancer (TNBC), immunotherapy acts in part by inducing ferroptosis. Recent studies have shown that protein arginine methyltransferase 5 (PRMT5) has distinct roles in immunotherapy among multiple cancers by modulating the tumor microenvironment. However, the role of PRMT5 during ferroptosis, especially for TNBC immunotherapy, is unclear.

METHODS

PRMT5 expression in TNBC was measured by IHC (immunohistochemistry) staining. To explore the function of PRMT5 in ferroptosis inducers and immunotherapy, functional experiments were conducted. A panel of biochemical assays was used to discover potential mechanisms.

RESULTS

PRMT5 promoted ferroptosis resistance in TNBC but impaired ferroptosis resistance in non-TNBC. Mechanistically, PRMT5 selectively methylated KEAP1 and thereby downregulated NRF2 and its downstream targets which can be divided into two groups: pro-ferroptosis and anti-ferroptosis. We found that the cellular ferrous level might be a critical factor in determining cell fate as NRF2 changes. In the context of higher ferrous concentrations in TNBC cells, PRMT5 inhibited the NRF2/HMOX1 pathway and slowed the import of ferrous. In addition, a high PRMT5 protein level indicated strong resistance of TNBC to immunotherapy, and PRMT5 inhibitors potentiated the therapeutic efficacy of immunotherapy.

CONCLUSIONS

Our results reveal that the activation of PRMT5 can modulate iron metabolism and drive resistance to ferroptosis inducers and immunotherapy. Accordingly, PRMT5 can be used as a target to change the immune resistance of TNBC.

Simvastatin inhibits hepatic stellate cells activation by regulating the ferroptosis signaling pathway

BACKGROUND & AIMS

Ferroptosis is a form of regulated cell death and its promotion in hepatic stellate cells (HSCs) attenuates liver fibrosis. Statins, which are 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, may induce ferroptosis via the downregulation of glutathione peroxidase 4 (GPX4) by inhibiting the mevalonate pathway. However, little evidence is available regarding the association between statins and ferroptosis. Therefore, we investigated the association between statins and ferroptosis in HSCs.

METHODS

Two human HSC cell lines, LX-2 and TWNT-1, were treated with simvastatin, an HMG-CoA reductase inhibitor. Mevalonic acid (MVA), farnesyl pyrophosphate (FPP), and geranylgeranyl pyrophosphate (GGPP) were used to determine the involvement of the mevalonate pathway. We performed a detailed analysis of the ferroptosis signaling pathway. We also investigated human liver tissue samples from patients with nonalcoholic steatohepatitis to clarify the effect of statins on GPX4 expression.

RESULTS

Simvastatin reduced cell mortality and inhibited HSCs activation, accompanied by iron accumulation, oxidative stress, lipid peroxidation, and reduced GPX4 protein expression. These results indicate that simvastatin inhibits HSCs activation by promoting ferroptosis. Furthermore, treatment with MVA, FPP, or GGPP attenuated simvastatin-induced ferroptosis. These results suggest that simvastatin promotes ferroptosis in HSCs by inhibiting the mevalonate pathway. In human liver tissue samples, statins downregulated the expression of GPX4 in HSCs without affecting hepatocytes.

CONCLUSIONS

Simvastatin inhibits the activation of HSCs by regulating the ferroptosis signaling pathway.

Autophagy-mediated ferroptosis involved in nickel-induced nephrotoxicity in the mice

Nickel, as a widely polluted metal, has been shown nephrotoxicity. Ferroptosis is a new type of cell death driven by iron-dependent lipid peroxidation. Our study found that nickel chloride (NiCl₂) induced ferroptosis in mouse kidney and TCMK-1 cells. The iron content was significantly increased in the kidney and TCMK-1 cells after NiCl₂ treatment. Lipid peroxidation and MDA content were significantly increased, and GSH content and T-SOD activity were significantly decreased after exposure to NiCl₂. Moreover, NiCl₂ increased COX-2 protein levels, decreased SLC7A11 and GPX4 protein levels, and elevated Ptgs2 mRNA levels. Next, the mechanism of Ni-induced ferroptosis was investigated. The results showed that NiCl₂ induced autophagy in TCMK-1 cells, which promoted ferroptosis induced by NiCl₂. Furthermore, the data of autophagy activation or inhibition experiment showed that autophagy facilitated ferroptosis through the degradation of the iron regulation protein NCOA4 and FTH1. Otherwise, iron chelator DFOM treatment inhibited ferroptosis induced by NiCl₂. Finally, ferroptosis inhibitor Fer-1 treatment significantly alleviated cytotoxicity induced by NiCl₂. To sum up, our above results showed that ferroptosis is involved in NiCl₂-induced nephrotoxicity, and NiCl₂ induces autophagy-dependent ferritin degradation, releases iron ions, leads to iron overload, and induces ferroptosis. This study supplies a new theoretical foundation for the study of nickel and renal toxicity.

Discovery of New 2-Phenylamino-3-acyl-1,4-naphthoquinones as Inhibitors of Cancer Cells Proliferation: Searching for Intra-Cellular Targets Playing a Role in Cancer Cells Survival

A series of 2-phenylamino-3-acyl-1,4-naphtoquinones were evaluated regarding their in vitro antiproliferative activities using DU-145, MCF-7 and T24 cancer cells. Such activities were discussed in terms of molecular descriptors such as half-wave potentials, hydrophobicity and molar refractivity. Compounds 4 and 11 displayed the highest antiproliferative activity against the three cancer cells and were therefore further investigated. The in silico prediction of drug likeness, using pkCSM and SwissADME explorer online, shows that compound 11 is a suitable lead molecule to be developed. Moreover, the expressions of key genes were studied in DU-145 cancer cells. They include genes involved in apoptosis (Bcl-2), tumor metabolism regulation (mTOR), redox homeostasis (GSR), cell cycle regulation (CDC25A), cell cycle progression (TP53), epigenetic (HDAC4), cell-cell communication (CCN2) and inflammatory pathways (TNF). Compound 11 displays an interesting profile because among these genes, mTOR was significantly less expressed as compared to control conditions. Molecular docking shows that compound 11 has good affinity with mTOR, unraveling a potential inhibitory effect on this protein. Due to the key role of mTOR on tumor metabolism, we suggest that impaired DU-145 cells proliferation by compound 11 is caused by a reduced mTOR expression (less mTOR protein) and inhibitory activity on mTOR protein.

Erianin inhibits the growth and metastasis through autophagy-dependent ferroptosis in KRASG13D colorectal cancer

Colorectal cancer (CRC) is the third most common cause of cancer mortality worldwide. Approximately 40% of CRC patients are KRAS sequence variation, including KRAS G13D mutation (KRAS^G13D) CRC patients, accounting for approximately 8% of all KRAS mutations in CRC patients and showing little benefit from anti-EGFR therapy. Therefore, there is an urgent need for new and effective anticancer agents in patients with KRAS^G13D CRC. Here, we identified a natural product, erianin, that directly interacted with purified recombinant human KRAS^G13D with a Kd of 1.1163 μM, which also significantly improve the thermal stability of KRAS^G13D. The cell viability assay showed that KRAS^G13D cells were more sensitive to erianin than KRAS^WT or KRAS^G12V cells. In vitro, results showed that erianin suppressed the migration, invasion and epithelial-mesenchymal transition (EMT) of KRAS^G13D CRC cells. Furthermore, erianin induced ferroptosis, as evidenced by the accumulation of Fe²⁺ and reactive oxygen species (ROS), lipid peroxidation, and changes in the mitochondrial morphology of KRAS^G13D CRC cells. Interestingly, we also found that erianin-induced ferroptosis was accompanied by autophagy. Moreover, the occurrence of erianin-induced ferroptosis is reversed by autophagy inhibitors (NH4Cl and Bafilomycin A1) and ATG5 knockdown, suggesting that erianin-induced ferroptosis is autophagy-dependent. In addition, we evaluated the inhibition of tumor growth and metastasis by erianin in vivo using a subcutaneous tumor model and a spleen-liver metastasis model, respectively. Collectively, these data provide novel insights into the anticancer activity of erianin, which is valuable for the further discussion and investigation of the use of erianin in clinical anticancer chemotherapy for KRAS^G13D CRC.

miR-491-5p regulates the susceptibility of glioblastoma to ferroptosis through TP53

BACKGROUND

Ferroptosis has excellent potential in glioblastoma (GBM) therapy. In this study, we attempted to explore the effect of miR 491-5p on ferroptosis in GBM.

METHODS

In this study, publicly available ferroptosis-related genome maps were used to screen genes upregulated in GBM and their target genes. The Spearman correlation coefficient was applied to analyze the correlation between the tumor protein p53 gene (TP53) and miR-491-5p. The expressions of miR-491-5p and TP53 were determined. The protein abundances of the TP53-encoded factors p53 and p21 were measured. Cell proliferation, migration and invasion were assessed. We pretreated U251MG cells and GBM mice with a ferroptosis inducer (erastin). The mitochondrial state was observed. The contents of reactive oxygen species (ROS), total Fe and Fe²⁺ were calculated.

RESULTS

The level of TP53 was significantly increased in GBM and negatively correlated with miR-491-5p. miR-491-5p overexpression promoted U251MG cell proliferation, migration and invasion and interfered with the p53/p21 pathway. TP53 supplement reversed the effects of miR-491-5p. U251MG cells and GBM mice exhibited significant accumulations of ROS and iron. Erastin promoted the expression of TP53. Inhibition of TP53 reversed erastin-induced physiological phenotypes. Moreover, miR-491-5p overexpression caused a decrease in the number of damaged mitochondria and the contents of ROS, total Fe and Fe²⁺. TP53 supplement disrupted miR-491-5p-repressed ferroptosis. Erastin could inhibit GBM growth, and miR-491-5p overexpression impeded the therapeutic effect of erastin.

CONCLUSIONS

Our findings reveal the functional diversity of miR-491-5p in GBM and suggest that miR-491-5p/TP53 signaling hinders the sensitivity of GBM to ferroptosis through the p53/p21 pathway.

Cadmium exposure during puberty damages testicular development and spermatogenesis via ferroptosis caused by intracellular iron overload and oxidative stress in mice

Cadmium (Cd) is a widespread environmental pollutant and a reproductive toxicant. It has been proved that Cd can reduce male fertility, however, the molecular mechanisms remain unveiled. This study aims to explore the effects and mechanisms of pubertal Cd exposure on testicular development and spermatogenesis. The results showed that Cd exposure during puberty could cause pathological damage to testes and reduce sperm counts in mice in adulthood. Moreover, Cd exposure during puberty reduced GSH content, induced iron overload and ROS production in testes, suggesting that Cd exposure during puberty may induce testicular ferroptosis. The results in vitro experiments further strengthened that Cd caused iron overload and oxidative stress, and decreased MMP in GC-1 spg cells. In addition, Cd disturbed intracellular iron homeostasis and peroxidation signal pathway based on transcriptomics analysis. Interestingly, these changes induced by Cd could be partially suppressed by pretreated with ferroptotic inhibitors, Ferrostatin-1 and Deferoxamine mesylate. In conclusion, the study demonstrated that Cd exposure during puberty maybe disrupted intracellular iron metabolism and peroxidation signal pathway, triggered ferroptosis in spermatogonia, and ultimately damaged testicular development and spermatogenesis in mice in adulthood.

A Carrier-Free Nanomedicine Enables Apoptosis-Ferroptosis Synergistic Breast Cancer Therapy by Targeting Subcellular Organelles

The heterogeneity of cancer cells disables the single-cell death patterns in subtypes of cells with different genotypes and phenotypes, such as refractory triple-negative breast cancer (TNBC). Therefore, the combination of multiple death modes, such as the proven cooperative apoptosis and ferroptosis, is expected to sensitize in treating TNBC. Herein, carrier-free theranostic ASP nanoparticles (NPs) were designed for wiping out TNBC by synergistic apoptosis and ferroptosis, which was self-assembled by aurantiamide acetate (Aa), scutebarbatine A (SA), and palmitin (P). Structurally, the rigid parent nucleus of SA and hydrophobic chain of P combined with the Aa to form an ordered nanostructure by noncovalent bonding forces. This self-assembly example applies to the design of nanomedicines based on more than two natural products. Notably, enhanced permeability and retention (EPR) effects and mitochondrial-lysosomal targeting empower ASP NPs to pinpoint tumor sites. Especially, Aa and P induced mitochondrial apoptosis of cancer cells, while SA and P inhibited TNBC by ferroptosis and upregulating p53. More interestingly, the combination of Aa, SA, and P enhanced the uptake of ASP NPs by cancer cell membranes. Overall, the three compounds synergize with each other to exert excellent anticancer effects.

A ferroptosis-related gene in Helicobacter pylori infection, SOCS1, serves as a potential prognostic biomarker and corresponds with tumor immune infiltration in stomach adenocarcinoma: In silico approach

OBJECTIVE

Helicobacter pylori (H. pylori) is a major risk factor for the stomach adenocarcinoma (STAD). This study aimed to investigate the potential role of a H. pylori infection-related gene, SOCS1, in STAD.

MATERIALS AND METHODS

Online available databases were analyzed to determine the expression, correlations with clinicopathologic parameters, patients' survival, and immunological characteristics of SOCS1 in TCGA-STAD or GEO datasets. Univariate and multivariate Cox regression analyses were used to determine independent risk factors, which were further integrated to establish a nomogram. A comparison of drug sensitivity was conducted for the chemotherapy responses between individuals with low- and high-SOCS1. Prediction of tumor response to checkpoint inhibitors was based on the tumor immunodeficiency and exclusion (TIDE) score.

RESULTS

SOCS1 expression was significantly increased in both H. pylori-infected and STAD patients. Higher SOCS1 expression indicated an undesirable prognosis in STAD patients. SOCS1 upregulation was related to enhanced immune cell infiltrations and the upregulation of immune checkpoints in STAD patients. N stage, age and SOCS1 were identified as independent risk factors for higher mortality of STAD patients and confirmed using the nomogram. Drug sensitivity analyses demonstrated that high expression of SOCS1 in STAD patients could improve the sensitivity to chemotherapy. TIDE score showed that STAD patients with high SOCS1 expression would have superior response to immunotherapy.

CONCLUSIONS

SOCS1 may act as a potential biomarker for uncovering the underlying mechanisms of gastric cancer. Increasing the activity of immunotherapy through ferroptosis-immunomodulation may be a viable strategy in STAD therapy.

Targeting ferroptosis, a novel programmed cell death, for the potential of alcohol-related liver disease therapy

Ferroptosis is a new iron-dependent cell death mode, which is different from the other types of programmed cell death, such as apoptosis, necrosis, and autophagy. Ferroptosis is characterized by a process in which fatal lipids from lipid peroxidation accumulate in cells and eventually lead to cell death. Alcohol-related liver disease (ALD) is a type of liver injury caused by excessive alcohol intake. Alcohol-related liver disease is a broad-spectrum disease category, which includes fatty liver, steatohepatitis, hepatitis, cirrhosis, and hepatocellular tumors. Recent studies have found that ferroptosis is involved in the pathological development of non-viral liver diseases. Therefore, ferroptosis may be an ideal target for the treatment of non-viral liver diseases. In this review article, we will elaborate the molecular mechanism and regulatory mechanism of ferroptosis, explore the key role of ferroptosis in the Alcohol-related liver disease process, and summarize the existing targeted ferroptosis drugs and their feasibility for the treatment of Alcohol-related liver disease.

TIGAR protects against adenine-induced ferroptosis in human proximal tubular epithelial cells by activating the mTOR/S6KP70 axis

TP53-induced glycolysis and apoptosis regulator (TIGAR) acts as a switch for nephropathy, but its underlying mechanism is still unclear. The purpose of this study was to explore the potential biological significance and underlying mechanism of TIGAR in modulating adenine-induced ferroptosis in human proximal tubular epithelial (HK-2) cells. HK-2 cells under- or overexpressing TIGAR were challenged with adenine to induce ferroptosis. The levels of reactive oxygen species (ROS), iron, malondialdehyde (MDA), and glutathione (GSH) were assayed. Expression of ferroptosis-associated solute carrier family seven-member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) at the level of mRNA and protein were measured by quantitative real-time-PCR and western blotting. The phosphorylation levels of proteins in the mTOR/S6KP70 pathway were determined by western blotting. Adenine overload triggered ferroptosis in HK-2 cells, as evidenced by reduced levels of GSH, SLC7A11, and GPX4, and increased levels of iron, MDA, and ROS. TIGAR overexpression repressed adenine-induced ferroptosis and induced mTOR/S6KP70 signaling. Inhibitors of mTOR and S6KP70 weakened the ability of TIGAR to inhibit adenine-induced ferroptosis. TIGAR inhibits adenine-induced ferroptosis in human proximal tubular epithelial cells by activating the mTOR/S6KP70 signaling pathway. Therefore, activating the TIGAR/mTOR/S6KP70 axis may be a treatment for crystal nephropathies.

Ferroptosis-modulating small molecules for targeting drug-resistant cancer: Challenges and opportunities in manipulating redox signaling

Ferroptosis is an iron-dependent cell death program that is characterized by excessive lipid peroxidation. Triggering ferroptosis has been proposed as a promising strategy to fight cancer and overcome drug resistance in antitumor therapy. Understanding the molecular interactions and structural features of ferroptosis-inducing compounds might therefore open the door to efficient pharmacological strategies against aggressive, metastatic, and therapy-resistant cancer. We here summarize the molecular mechanisms and structural requirements of ferroptosis-inducing small molecules that target central players in ferroptosis. Focus is placed on (i) glutathione peroxidase (GPX) 4, the only GPX isoenzyme that detoxifies complex membrane-bound lipid hydroperoxides, (ii) the cystine/glutamate antiporter system Xc - that is central for glutathione regeneration, (iii) the redox-protective transcription factor nuclear factor erythroid 2-related factor (NRF2), and (iv) GPX4 repression in combination with induced heme degradation via heme oxygenase-1. We deduce common features for efficient ferroptotic activity and highlight challenges in drug development. Moreover, we critically discuss the potential of natural products as ferroptosis-inducing lead structures and provide a comprehensive overview of structurally diverse biogenic and bioinspired small molecules that trigger ferroptosis via iron oxidation, inhibition of the thioredoxin/thioredoxin reductase system or less defined modes of action.

Emerging role of ferroptosis-related circular RNA in tumor metastasis

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

Iron deficiency in hepatocellular carcinoma cells induced sorafenib resistance by upregulating HIF-1α to inhibit apoptosis

Sorafenib is the first-line therapeutic agent for hepatocellular carcinoma (HCC), but the drug resistance has become a major impediment. Previously we found that the abnormal iron metabolism in HCC led to iron deficiency, whether it induces sorafenib resistance during the treatment of HCC is not yet disclosed. In this study, we observed the effects of iron deficiency on sorafenib resistance and explored the underlying mechanisms. The results revealed that the killing effects of sorafenib on HCC cells were weakened by iron deficiency but effectively restored by iron re-supplementation. The ferroptosis indicators, including the contents of lipid hydroperoxide (LPO) and malondialdehyde (MDA), the level of intracellular reactive oxygen species (ROS), and the expression of glutathione peroxidase 4 (GPX4), were not significantly changed by iron deficiency in sorafenib-treated HCC cells. However, the sorafenib-induced apoptosis of HCC cells was inhibited by iron deficiency. Notably, the expression of anti-apoptotic protein B-cell lymphoma-2 (BCL-2) was elevated, and the expressions of other apoptotic proteins, BCL2-associated X (Bax), caspase-3, and caspase-9, were inhibited by iron deficiency. Mechanistically, iron deficiency upregulated hypoxia-inducible factor 1 alpha (HIF-1α) to increase BCL-2. Inhibition of HIF-1α suppressed the iron deficiency-induced BCL-2 and sorafenib resistance. In summary, iron deficiency in HCC cells generated sorafenib resistance by increasing HIF-1α and BCL-2, which therefore inhibited the sorafenib-induced apoptosis of HCC cells. These results identified iron deficiency as a new factor of sorafenib resistance in HCC cells, which would be an effective target to alleviate sorafenib resistance.

n-3 PUFA Promotes Ferroptosis in PCOS GCs by Inhibiting YAP1 through Activation of the Hippo Pathway

Polycystic ovary syndrome (PCOS) is an endocrine disorder characterized by hyperandrogenemia with multiple suspended sinus follicles, thickened cortical tissue, and excessive proliferation of ovarian granulosa cells that severely affects the fertility and quality of life of women. The addition of n-3 PUFA to the diet may slightly reduce body weight and greatly alleviate disturbed blood hormone levels in PCOS mice. We treated KGN as a cell model for n-3 PUFA addition and showed that n-3 PUFA inhibited the proliferation of GCs and promoted ferroptosis in ovarian granulosa cells. We used CCK-8, fluorescence quantitative transmission electron microscopy experiments and ferroptosis marker gene detection and other methods. Furthermore, n-3 PUFA was found to promote YAP1 exocytosis by activating Hippo and weakening the cross-talk between YAP1 and Nrf2 by activating the Hippo signaling pathway. In this study, we found that n-3 PUFA inhibited the over proliferation of granulosa cells in ovarian follicles by activating Hippo, promoting YAP1 exocytosis, weakening the cross-talk between YAP1 and Nrf2, and ultimately activating the ferroptosis sensitivity of ovarian granulosa cells. We demonstrate that n-3 PUFA can alleviate the hormonal and estrous cycle disorder with PCOS by inhibiting the YAP1-Nrf2 crosstalk that suppresses over proliferating ovarian granulosa cells and promotes iron death in GCs. These findings reveal the molecular mechanisms by which n-3 PUFA attenuates PCOS and identify YAP1-Nrf2 as a potential therapeutic target for regulation granulosa cells in PCOS.

Ferroptosis landscape in prostate cancer from molecular and metabolic perspective

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

Diplacone Isolated from Paulownia tomentosa Mature Fruit Induces Ferroptosis-Mediated Cell Death through Mitochondrial Ca2+ Influx and Mitochondrial Permeability Transition

The recently defined type of cell death ferroptosis has garnered significant attention as a potential new approach to cancer treatment owing to its more immunogenic nature when compared with apoptosis. Ferroptosis is characterized by the depletion of glutathione (GSH)/glutathione peroxidase-4 (GPx4) and iron-dependent lipid peroxidation. Diplacone (DP), a geranylated flavonoid compound found in Paulownia tomentosa fruit, has been identified to have anti-inflammatory and anti-radical activity. In this study, the potential anticancer activity of DP was explored against A549 human lung cancer cells. It was found that DP induced a form of cytotoxicity distinct from apoptosis, which was accompanied by extensive mitochondrial-derived cytoplasmic vacuoles. DP was also shown to increase mitochondrial Ca2+ influx, reactive oxygen species (ROS) production, and mitochondrial permeability transition (MPT) pore-opening. These changes led to decreases in mitochondrial membrane potential and DP-induced cell death. DP also induced lipid peroxidation and ATF3 expression, which are hallmarks of ferroptosis. The ferroptosis inhibitors ferrostatin-1 and liproxstatin-1 were effective in counteracting the DP-mediated ferroptosis-related features. Our results could contribute to the use of DP as a ferroptosis-inducing agent, enabling studies focusing on the relationship between ferroptosis and the immunogenic cell death of cancer cells.

Inaugurating a novel adjuvant therapy in urological cancers: Ferroptosis

Ferroptosis, a distinctive form of programmed cell death, is involved in numerous diseases with specific characteristics, including certain cell morphology, functions, biochemistry, and genetics, that differ from other forms of programmed cell death, such as apoptosis. Many studies have explored ferroptosis and its associated mechanisms, drugs, and clinical applications in diseases such as kidney injury, stroke, ischemia-reperfusion injury, and prostate cancer. In this review, we summarize the regulatory mechanisms of some ferroptosis inducers, such as enzalutamide and erastin. These are current research focuses and have already been studied extensively. In summary, this review focuses on the use of ferroptosis induction as a therapeutic strategy for treating tumors of the urinary system.

Fatostatin induces ferroptosis through inhibition of the AKT/mTORC1/GPX4 signaling pathway in glioblastoma

Glioblastoma multiforme (GBM) is the most common and fatal primary malignant central nervous system tumor in adults. Although there are multiple treatments, the median survival of GBM patients is unsatisfactory, which has prompted us to continuously investigate new therapeutic strategies, including new drugs and drug delivery approaches. Ferroptosis, a kind of regulated cell death (RCD), has been shown to be dysregulated in various tumors, including GBM. Fatostatin, a specific inhibitor of sterol regulatory element binding proteins (SREBPs), is involved in lipid and cholesterol synthesis and has antitumor effects in a variety of tumors. However, the effect of fatostatin has not been explored in the field of ferroptosis or GBM. In our study, through transcriptome sequencing, in vivo experiments, and in vitro experiments, we found that fatostatin induces ferroptosis by inhibiting the AKT/mTORC1/GPX4 signaling pathway in glioblastoma. In addition, fatostatin inhibits cell proliferation and the EMT process through the AKT/mTORC1 signaling pathway. We also designed a p28-functionalized PLGA nanoparticle loaded with fatostatin, which could better cross the blood-brain barrier (BBB) and be targeted to GBM. Our research identified the unprecedented effects of fatostatin in GBM and presented a novel drug-targeted delivery vehicle capable of penetrating the BBB in GBM.

Wild-type and mutant p53 in cancer-related ferroptosis. A matter of stress management?

Cancer cells within tumor masses are chronically exposed to stress caused by nutrient deprivation, oxygen limitation, and high metabolic demand. They also accumulate hundreds of mutations, potentially generating aberrant proteins that can induce proteotoxic stress. Finally, cancer cells are exposed to various damages during chemotherapy. In a growing tumor, transformed cells eventually adapt to these conditions, eluding the death-inducing outcomes of signaling cascades triggered by chronic stress. One such extreme outcome is ferroptosis, a form of iron-dependent non-apoptotic cell death mediated by lipid peroxidation. Not surprisingly, the tumor suppressor p53 is involved in this process, with evidence suggesting that it acts as a pro-ferroptotic factor and that its ferroptosis-inducing activity may be relevant for tumor suppression. Missense alterations of the TP53 gene are extremely frequent in human cancers and give rise to mutant p53 proteins (mutp53) that lose tumor suppressive function and can acquire powerful oncogenic activities. This suggests that p53 mutation provides a selective advantage during tumor progression, raising interesting questions on the impact of p53 mutant proteins in modulating the ferroptotic process. Here, we explore the role of p53 and its cancer-related mutants in ferroptosis, using a perspective centered on the resistance/sensitivity of cancer cells to exogenous and endogenous stress conditions that can trigger ferroptotic cell death. We speculate that an accurate molecular understanding of this particular axis may improve cancer treatment options.

Long noncoding RNAs induced control of ferroptosis: Implications in cancer progression and treatment

A novel kind of nonapoptotic, iron-dependent cell death brought on by lipid peroxidation is known as ferroptosis. Numerous pathological processes, including neurotoxicity, neurological disorders, ischemia-reperfusion damage, and particularly cancer, have been demonstrated to be influenced by changes in the ferroptosis-regulating network. Recent studies have established the critical roles that ferroptosis can play in cancer development and the evolution of resistance to standard chemoradiotherapy, thus suggesting that ferroptosis may be a feasible therapeutic strategy for cancer management. Gene expression may be regulated at the transcriptional and posttranscriptional levels by long noncoding RNAs (lncRNAs). They have been implicated in tumorigenesis. Some lncRNAs participate in the biological process of ferroptosis, which represents an exciting alternative to regulate ferroptosis as a means of cancer therapy. Even though there is evidence that lncRNAs have a mechanistic role in the ferroptosis of cancer cells, research on the mechanism and potential treatments for these lncRNAs is still lacking. We elucidate the potential mechanisms by which lncRNAs modulate ferroptosis in cancer and examine the promise and challenges of employing lncRNAs as novel therapeutic targets in cancer.

Self-assembled nanomaterials for ferroptosis-based cancer theranostics

Most ferroptosis nanomedicines based on organic or inorganic carriers have difficulties in further clinical translation due to their serious side effects and complicated preparation. Self-assembled nanomedicines can reduce the biological toxicity caused by additional chemical modifications and excipients, offering better biocompatibility and safety. Ferroptosis therapy is an iron-associated programmed cell death dependent on lipid peroxidation with efficient tumor selectivity and biosafety. Therefore, the application of self-assembled nanomedicines with good biosafety in the ferroptosis treatment of tumors has attracted extensive attention. In this review, recent advances in the field of ferroptosis-based self-assembled nanomaterials for cancer therapy are presented, with emphasis on how these nanomaterial components interact and their distinct mechanisms for inducing ferroptosis in tumor cells, including iron metabolism, amino acid metabolism and CoQ/FSP1, as well as their respective advantages and challenges. This review would therefore help the spectrum of advanced and novice researchers interested in this area to quickly zoom in on the essential information and glean some thought-provoking ideas to advance this subfield in cancer nanomedicine.

Development and validation of a combined hypoxia and ferroptosis prognostic signature for breast cancer

Background

Hypoxia is involved in tumor biological processes and disease progression. Ferroptosis, as a newly discovered programmed cell death process, is closely related to breast cancer (BC) occurrence and development. However, reliable prognostic signatures based on a combination of hypoxia and ferroptosis in BC have not been developed.

Method

We set The Cancer Genome Atlas (TCGA) breast cancer cohort as training set and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) BC cohort as the validation set. Least Absolute Shrinkage and Selection Operator (LASSO) and COX regression approaches were used to construct ferroptosis-related genes (FRGs) and hypoxia-related genes (HRGs) prognostic signature (HFRS). The CIBERSORT algorithm and ESTIMATE score were used to explore the relationship between HFRS and tumor immune microenvironment. Immunohistochemical staining was used to detect protein expression in tissue samples. A nomogram was developed to advance the clinical application of HFRS signature.

Results

Ten ferroptosis-related genes and hypoxia-related genes were screened to construct the HFRS prognostic signature in TCGA BC cohort, and the predictive capacity was verified in METABRIC BC cohort. BC patients with high-HFRS had shorter survival time, higher tumor stage, and a higher rate of positive lymph node. Moreover, high HFRS was associated with high hypoxia, ferroptosis, and immunosuppression status. A nomogram that was constructed with age, stage, and HFRS signature showed a strong prognostic capability to predict overall survival (OS) for BC patients.

Conclusion

We developed a novel prognostic model with hypoxia and ferroptosis-related genes to predict OS, and characterize the immune microenvironment of BC patients, which might provide new cures for clinical decision-making and individual treatment of BC patients.

Research progress of traditional Chinese medicine as sensitizer in reversing chemoresistance of colorectal cancer

In recent years, the incidences and mortalities from colorectal cancer (CRC) have been increasing; therefore, there is an urgent need to discover newer drugs that enhance drug sensitivity and reverse drug tolerance in CRC treatment. With this view, the current study focuses on understanding the mechanism of CRC chemoresistance to the drug as well as exploring the potential of different traditional Chinese medicine (TCM) in restoring the sensitivity of CRC to chemotherapeutic drugs. Moreover, the mechanism involved in restoring sensitivity, such as by acting on the target of traditional chemical drugs, assisting drug activation, increasing intracellular accumulation of anticancer drugs, improving tumor microenvironment, relieving immunosuppression, and erasing reversible modification like methylation, have been thoroughly discussed. Furthermore, the effect of TCM along with anticancer drugs in reducing toxicity, increasing efficiency, mediating new ways of cell death, and effectively blocking the drug resistance mechanism has been studied. We aimed to explore the potential of TCM as a sensitizer of anti-CRC drugs for the development of a new natural, less-toxic, and highly effective sensitizer to CRC chemoresistance.

Fighting age-related orthopedic diseases: focusing on ferroptosis

Ferroptosis, a unique type of cell death, is characterized by iron-dependent accumulation and lipid peroxidation. It is closely related to multiple biological processes, including iron metabolism, polyunsaturated fatty acid metabolism, and the biosynthesis of compounds with antioxidant activities, including glutathione. In the past 10 years, increasing evidence has indicated a potentially strong relationship between ferroptosis and the onset and progression of age-related orthopedic diseases, such as osteoporosis and osteoarthritis. Therefore, in-depth knowledge of the regulatory mechanisms of ferroptosis in age-related orthopedic diseases may help improve disease treatment and prevention. This review provides an overview of recent research on ferroptosis and its influences on bone and cartilage homeostasis. It begins with a brief overview of systemic iron metabolism and ferroptosis, particularly the potential mechanisms of ferroptosis. It presents a discussion on the role of ferroptosis in age-related orthopedic diseases, including promotion of bone loss and cartilage degradation and the inhibition of osteogenesis. Finally, it focuses on the future of targeting ferroptosis to treat age-related orthopedic diseases with the intention of inspiring further clinical research and the development of therapeutic strategies.

Sorafenib triggers ferroptosis via inhibition of HBXIP/SCD axis in hepatocellular carcinoma

Sorafenib, which inhibits multiple kinases, is an effective frontline therapy for hepatocellular carcinoma (HCC). Ferroptosis is a form of iron-dependent programmed cell death regulated by lipid peroxidation, which can be induced by sorafenib treatment. Oncoprotein hepatitis B X-interacting protein (HBXIP) participates in multiple biological pro-tumor processes, including growth, metastasis, drug resistance, and metabolic reprogramming. However, the role of HBXIP in sorafenib-induced ferroptotic cell death remains unclear. In this study, we demonstrated that HBXIP prevents sorafenib-induced ferroptosis in HCC cells. Sorafenib decreased HBXIP expression, and overexpression of HBXIP blocked sorafenib-induced HCC cell death. Interestingly, suppression of HBXIP increased malondialdehyde (MDA) production and glutathione (GSH) depletion to promote sorafenib-mediated ferroptosis and cell death. Ferrostatin-1, a ferroptosis inhibitor, reversed the enhanced anticancer effect of sorafenib caused by HBXIP silencing in HCC cells. Regarding the molecular mechanism, HBXIP transcriptionally induced the expression of stearoyl-CoA desaturase (SCD) via coactivating the transcriptional factor ZNF263, resulting in the accumulation of free fatty acids and suppression of ferroptosis. Functionally, activation of the HBXIP/SCD axis reduced the anticancer activity of sorafenib and suppressed ferroptotic cell death in vivo and in vitro. HBXIP/SCD axis-mediated ferroptosis can serve as a novel downstream effector of sorafenib. Our results provide new evidence for clinical decisions in HCC therapy.

GPX4: The hub of lipid oxidation, ferroptosis, disease and treatment

Glutathione peroxidase 4 (GPx4) moonlights as structural protein and antioxidase that powerfully inhibits lipid oxidation. In the past years, it is considered as a key regulator of ferroptosis, which takes role in the lipid and amine acid metabolism and influences the cell aging, oncogenesis, and cell death. More and more evidences show that targeting GPX4-induced ferroptosis is a promising strategy for disease therapy, especially cancer treatment. In view of these, we generalize the function of GPX4 and regulatory mechanism between GPX4 and ferroptosis, discuss its roles in the disease pathology, and focus on the recent advances of disease therapeutic potential.

The Gut Microbiome and Ferroptosis in MAFLD

Metabolic-associated fatty liver disease (MAFLD) is a new disease definition, and is proposed to replace the previous name, nonalcoholic fatty liver disease (NAFLD). Globally, MAFLD/NAFLD is the most common liver disease, with an incidence rate ranging from 6% to 35% in adult populations. The pathogenesis of MAFLD/NAFLD is closely related to insulin resistance (IR), and the genetic susceptibility to acquired metabolic stress-associated liver injury. Similarly, the gut microbiota in MAFLD/NAFLD is being revaluated by scientists, as the gut and liver influence each other via the gut-liver axis. Ferroptosis is a novel form of programmed cell death caused by iron-dependent lipid peroxidation. Emerging evidence suggests that ferroptosis has a key role in the pathological progression of MAFLD/NAFLD, and inhibition of ferroptosis may become a novel therapeutic strategy for the treatment of NAFLD. This review focuses on the main mechanisms behind the promotion of MAFLD/NAFLD occurrence and development by the intestinal microbiota and ferroptosis. It outlines new strategies to target the intestinal microbiota and ferroptosis to facilitate future MAFLD/NAFLD therapies.

Curcumin Represses Colorectal Cancer Cell Proliferation by Triggering Ferroptosis via PI3K/Akt/mTOR Signaling

Curcumin is known to suppress the progression of colorectal cancer by inhibiting cancer cell proliferation. In this study, we explored the role of ferroptosis in the antiproliferative properties of curcumin. The effect of curcumin on ferroptosis In Vitro was evaluated in HCT-8 cells. Ferroptosis was first blocked by ferrostatin-1 (Fer-1) and the antiproliferative effect of curcumin was evaluated by determining the levels of ferroptotic markers, including glutathione (GSH), SLC7A11, GPX4, iron, malondialdehyde (MDA), and reactive oxygen species (ROS). An agonist and an inhibitor of PI3K were also used to verify the signaling pathway involved in the antiproliferative effects. Curcumin repressed HCT-8 cell proliferation in a dose-dependent manner. Treating HCT-8 cells with curcumin significantly downregulated GSH, SLC7A11, and GPX4, while significantly increasing levels of iron, MDA, and ROS. In addition, curcumin promoted ferroptosis and reduced proliferation of HCT-8 cells by suppressing the PI3K/Akt/mTOR pathway, and these effects were antagonized by Fer-1. The effects of curcumin were antagonized by a PI3K agonist and reinforced by a PI3K inhibitor. Curcumin triggers ferroptosis and suppresses proliferation of colorectal cancer cells by inhibiting the PI3K/Akt/mTOR signaling pathway. These results indicate its potential as a treatment against colorectal cancer.

Prognostic Significance of Iron Metabolism Related Genes in Human Lung Adenocarcinoma

Background

Iron metabolism related genes participate in cell proliferation, cell growth, and redox cycling in multiple cancers. Limited studies have revealed the roles and clinical significance of iron metabolism in the pathogenesis and prognosis of lung cancer.

Methods

A total of 119 iron metabolism related genes were extracted from MSigDB database and their prognostic values were determined in The Cancer Genome Atlas lung adenocarcinoma (TCGA-LUAD) dataset and the Gene Expression Profiling Interactive Analysis 2 (GEPIA 2) database. Immunohistochemistry technique and correlations with immune cell infiltration, gene mutation and drug resistance were used to identify the potential and underlying mechanisms of STEAP1 and STEAP2 as prognostic biomarkers of LUAD.

Results

The expression of STEAP1 and STEAP2 are negatively associated with the prognosis of LUAD patients both at the mRNA and protein level. The expression of STEAP1 and STEAP2 was not only negatively correlated with the trafficking degree of CD4+ T immune cells and positively related to most immune cells' trafficking degree, but also significantly associated with gene mutation status, particularly with mutations on TP53 and STK11. Four types of drug resistance showed significant correlation with the expression level of STEAP1 while 13 types of drug resistance were associated with the expression level of STEAP2.

Conclusion

Multiple iron metabolism related genes including STEAP1 and STEAP2 are significantly associated with the prognosis of LUAD patients. STEAP1 and STEAP2 might affect the prognosis of LUAD patients partially through immune cell infiltration, gene mutation and drug resistance, which indicated they were independent prognostic factors for LUAD patients.