Acetylation Is Crucial for p53-Mediated Ferroptosis and Tumor Suppression

Acetylation, ferroptosis, and their potential relationships: Implications in myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury (MIRI) is a serious complication affecting the prognosis of patients with myocardial infarction and can cause cardiac arrest, reperfusion arrhythmias, no-reflow, and irreversible myocardial cell death. Ferroptosis, an iron-dependent, peroxide-driven, non-apoptotic form of regulated cell death, plays a vital role in reperfusion injury. Acetylation, an important post-translational modification, participates in many cellular signaling pathways and diseases, and plays a pivotal role in ferroptosis. Elucidating the role of acetylation in ferroptosis may therefore provide new insights for the treatment of MIRI. Here, we summarized the recently discovered knowledge about acetylation and ferroptosis in MIRI. Finally, we focused on the acetylation modification during ferroptosis and its potential relationship with MIRI.

Reactive Oxygen Species and Ferroptosis at the Nexus of Inflammation and Colon Cancer

Significance: Reactive oxygen species (ROS) are essential in maintaining normal intestinal physiology. Inflammatory bowel disease (IBD) is a relapsing chronic inflammatory disease of the intestine that is a major risk factor for colorectal cancer (CRC). Excess ROS are widely implicated in intestinal inflammation and cancer. Recent Advances: Clinical data have shown that targeting ROS broadly does not yield improved outcomes in IBD and CRC. However, selectively limiting oxidative damage may improve the efficacy of ROS targeting. An accumulation of lipid ROS induces a novel oxidative cell death pathway known as ferroptosis. A growing body of evidence suggests that ferroptosis is relevant to both IBD and CRC. Critical Issues: We propose that inhibition of ferroptosis will improve disease severity in IBD, whereas activating ferroptosis will limit CRC progression. Data from preclinical models suggest that methods of modulating ferroptosis have been successful in attenuating IBD and CRC. Future Directions: The etiology of IBD and progression of IBD to CRC are still unclear. Further understanding of ferroptosis in intestinal diseases will provide novel therapies. Ferroptosis is highly linked to inflammation, cell metabolism, and is cell-type dependent. Further research in assessing the inflammatory and tumor microenvironment in the intestine may provide novel vulnerabilities that can be targeted. Antioxid. Redox Signal. 39, 551-568.

A p53/LINC00324 positive feedback loop suppresses tumor growth by counteracting SET-mediated transcriptional repression

The p53 tumor suppressor exerts antitumor functions through its ability to regulate the transcription of its downstream targets. Long noncoding RNAs (lncRNAs) act as oncogenes or tumor suppressors implicated in tumorigenesis and tumor progression. Here, we identify the lncRNA LINC00324 (long intergenic noncoding RNA 00324) as a direct p53 transcriptional target. Knockdown of LINC00324 expression promotes tumor growth by reducing p53 transcriptional activity, whereas ectopic LINC00324 expression demonstrates a reverse effect. Notably, LINC00324 is present in the endogenous p53 complex in tumor cells and directly binds to the C-terminal domain of p53 in vitro. Mechanistically, LINC00324 enables p53 transactivation by competitively disrupting the p53-SET interaction, resulting in an increase of p300/CBP-mediated H3K18 and H3K27 acetylation on the p53 target promoters. Lower LINC00324 expression is associated with more aggressive disease status and predicts worse overall survival of patients with cancer. Our study identifies a p53/LINC00324 positive feedback loop that suppresses tumor growth by counteracting SET-mediated transcriptional repression.

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.

Molecular subtyping of acute myeloid leukemia through ferroptosis signatures predicts prognosis and deciphers the immune microenvironment

Acute myeloid leukemia (AML) is one of the most aggressive hematological malignancies with a low 5-year survival rate and high rate of relapse. Developing more efficient therapies is an urgent need for AML treatment. Accumulating evidence showed that ferroptosis, an iron-dependent form of programmed cell death, is closely correlated with cancer initiation and clinical outcome through reshaping the tumor microenvironment. However, understanding of AML heterogeneity based on extensive profiling of ferroptosis signatures remains to be investigated yet. Herein, five independent AML transcriptomic datasets (TCGA-AML, GSE37642, GSE12417, GSE10358, and GSE106291) were obtained from the GEO and TCGA databases. Then, we identified two ferroptosis-related molecular subtypes (C1 and C2) with distinct prognosis and tumor immune microenvironment (TIME) by consensus clustering. Patients in the C1 subtype were associated with favorable clinical outcomes and increased cytotoxic immune cell infiltration, including CD8+/central memory T cells, natural killer (NK) cells, and non-regulatory CD4+ T cells while showing decreased suppressive immune subsets such as M2 macrophages, neutrophils, and monocytes. Functional enrichment analysis of differentially expressed genes (DEGs) implied that cell activation involved in immune response, leukocyte cell-cell adhesion and migration, and cytokine production were the main biological processes. Phagosome, antigen processing and presentation, cytokine-cytokine receptor interaction, B-cell receptor, and chemokine were identified as the major pathways. To seize the distinct landscape in C1 vs. C2 subtypes, a 5-gene prognostic signature (LSP1, IL1R2, MPO, CRIP1, and SLC24A3) was developed using LASSO Cox stepwise regression analysis and further validated in independent AML cohorts. Patients were divided into high- and low-risk groups, and decreased survival rates were observed in high- vs. low-risk groups. The TIME between high- and low-risk groups has a similar scenery in C1 vs. C2 subtypes. Single-cell-level analysis verified that LSP1 and CRIP1 were upregulated in AML and exhausted CD8+ T cells. Dual targeting of these two markers might present a promising immunotherapeutic for AML. In addition, potential effective chemical drugs for AML were predicted. Thus, we concluded that molecular subtyping using ferroptosis signatures could characterize the TIME and provide implications for monitoring clinical outcomes and predicting novel therapies.

The diversified role of mitochondria in ferroptosis in cancer

Ferroptosis is a form of regulated cell death induced by iron-dependent lipid peroxidation, and it has been studied extensively since its discovery in 2012. Induced by iron overload and ROS accumulation, ferroptosis is modulated by various cellular metabolic and signaling pathways. The GSH-GPX4 pathway, the FSP1-CoQ10 pathway, the GCH1-BH4 pathway, the DHODH-CoQH2 system and the sex hormones suppress ferroptosis. Mitochondrial iron metabolism regulates ferroptosis and mitochondria also undergo a morphological change during ferroptosis, these changes include increased membrane density and reduced mitochondrial cristae. Moreover, mitochondrial energy metabolism changes during ferroptosis, the increased oxidative phosphorylation and ATP production rates lead to a decrease in the glycolysis rate. In addition, excessive oxidative stress induces irreversible damage to mitochondria, diminishing organelle integrity. ROS production, mitochondrial membrane potential, mitochondrial fusion and fission, and mitophagy also function in ferroptosis. Notably, some ferroptosis inhibitors target mitochondria. Ferroptosis is a major mechanism for cell death associated with the progression of cancer. Metastasis-prone or metastatic cancer cells are more susceptible to ferroptosis. Inducing ferroptosis in tumor cells shows very promising potential for treating drug-resistant cancers. In this review, we present a brief retrospect of the discovery and the characteristics of ferroptosis, then we discuss the regulation of ferroptosis and highlight the unique role played by mitochondria in the ferroptosis of cancer cells. Furthermore, we explain how ferroptosis functions as a double-edged sword as well as novel therapies aimed at selectively manipulating cell death for cancer eradication.

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.

Ferroptosis as a potential target for cancer therapy

Ferroptosis is a recently discovered essential type of cell death that is mainly characterized by iron overload and lipid peroxidation. Emerging evidence suggests that ferroptosis is a double-edged sword in human cancer. However, the precise underlying molecular mechanisms and their differential roles in tumorigenesis are unclear. Therefore, in this review, we summarize and briefly present the key pathways of ferroptosis, paying special attention to the regulation of ferroptosis as well as its dual role as an oncogenic and as a tumor suppressor event in various human cancers. Moreover, multiple pharmacological ferroptosis activators are summarized, and the prospect of targeting ferroptosis in cancer therapy is further elucidated.

Bioinformatics identification of ferroptosis-related genes and therapeutic drugs in rheumatoid arthritis

Introduction

Rheumatoid arthritis (RA) is a chronic immune disease characterized by synovial inflammation and bone destruction, with a largely unclear etiology. Evidence has indicated that ferroptosis may play an increasingly important role in the onset and development of RA. However, ferroptosis-related genes are still largely unexplored in RA. Therefore, this work focused on identifying and validating the potential ferroptosis-related genes involved in RA through bioinformatics analysis.

Methods

We screened differentially expressed ferroptosis-related genes (DEFGs) between RA patients and healthy individuals based on GSE55235 dataset. Subsequently, correlation analysis, protein-protein interaction (PPI) network analysis, GO, and KEGG enrichment analyses were performed using these DEFGs. Finally, our results were validated by GSE12021 dataset.

Results

We discovered 34 potential DEFGs in RA based on bioinformatics analysis. According to functional enrichment analysis, these genes were mainly enriched in HIF-1 signaling pathway, FoxO signaling pathway, and Ferroptosis pathway. Four genes (GABARPL1, DUSP1, JUN, and MAPK8) were validated to be downregulated by GSE12021 dataset and were diagnostic biomarkers and therapeutic targets for RA via the regulation of ferroptosis.

Discussion

Our results help shed more light on the pathogenesis of RA. Ferroptosis-related genes in RA are valuable diagnostic biomarkers and they will be exploited clinically as therapeutic targets in the future.

Acetylation Targeting Chimera Enables Acetylation of the Tumor Suppressor p53

With advances in chemically induced proximity technologies, heterobifunctional modalities such as proteolysis targeting chimeras (PROTACs) have been successfully advanced to clinics for treating cancer. However, pharmacologic activation of tumor-suppressor proteins for cancer treatment remains a major challenge. Here, we present a novel Acetylation Targeting Chimera (AceTAC) strategy to acetylate the p53 tumor suppressor protein. We discovered and characterized the first p53Y220C AceTAC, MS78, which recruits histone acetyltransferase p300/CBP to acetylate the p53Y220C mutant. MS78 effectively acetylated p53Y220C lysine 382 (K382) in a concentration-, time-, and p300-dependent manner and suppressed proliferation and clonogenicity of cancer cells harboring the p53Y220C mutation with little toxicity in cancer cells with wild-type p53. RNA-seq studies revealed novel p53Y220C-dependent upregulation of TRAIL apoptotic genes and downregulation of DNA damage response pathways upon acetylation induced by MS78. Altogether, the AceTAC strategy could provide a generalizable platform for targeting proteins, such as tumor suppressors, via acetylation.

Novel target for treatment of colorectal cancer: Metabolism and regulatory mechanisms of ferroptosis

Ferroptosis is a new type of programmed cell death charac-terized by intracellular iron overload and lipid peroxidation accumulation. In the past 10 years, research has demonstrated that intervention of ferroptosis can effectively prevent or treat cancer diseases, including colorectal cancer. However, the role of ferroptosis in different types of colorectal cancer is not the same. This article summarizes the three major pathways involved in the occurrence and development of ferroptosis, namely, iron metabolism, lipid metabolism, and amino acid metabolism, and discusses the specific mechanisms and clinical applications of ferroptosis targeted therapy in colorectal cancer of various consensus molecular subtypes. Existing studies have shown that ferroptosis targeted therapy has broad application prospects in optimizing the comprehensive treatment of colorectal cancer. This article will provide an important framework for studying the mechanism of ferroptosis in tumor prevention and treatment and have guiding significance in exploring the application of ferroptosis targeted therapy in the treatment of different types of colorectal cancer.

Alternatively mechanistic insights into acetylation in p53-mediated transcriptional regulation of cancer cell-intrinsic PD-1

Since the recent discovery of cancer cell-intrinsic programmed cell death protein-1 (PD-1), the mechanisms that manipulate PD-1 functions in tumor development beyond its immune checkpoint roles have become attractive research topics in oncology. Our previous study validated that PD-1 exists in lung cancer cells and is directly transactivated by p53 in a DNA-binding domain (DBD) acetylation-dependent manner. Here, we report that the carboxyl-terminal domain (CTD) of p53 likewise participates in PD-1 transcriptional regulation in cancer cells under different regulatory mechanisms. By mutating the lysine residues within the CTD to mimic either acetylation-deficient or fully acetylated status, we proved that acetylated CTD dramatically impeded p53-mediated transactivation of PD-1. Furthermore, we identified bromodomain-containing protein 4 (BRD4) as a transcriptional coactivator of p53 that facilitates p53-mediated PD-1 transcription. Mechanistically, BRD4 specifically bound to the unacetylated CTD of p53, while CTD acetylation almost completely destroyed the BRD4-p53 interaction and thus led to compromised PD-1 expression. Collectively, this study unveils an alternative mechanism of p53 acetylation-directed PD-1 transcriptional regulation, which would broaden our current understanding of the molecular regulatory network of cancer cell-intrinsic PD-1.

The epigenetic regulatory mechanisms of ferroptosis and its implications for biological processes and diseases

Ferroptosis is a form of regulated cell death triggered by the iron-dependent peroxidation of phospholipids. Interactions of iron and lipid metabolism factors jointly promote ferroptosis. Ferroptosis has been demonstrated to be involved in the development of various diseases, such as tumors and degenerative diseases (e.g., aortic dissection), and targeting ferroptosis is expected to be an effective strategy for the treatment of these diseases. Recent studies have shown that the regulation of ferroptosis is affected by multiple mechanisms, including genetics, epigenetics, posttranscriptional modifications, and protein posttranslational modifications. Epigenetic changes have garnered considerable attention due to their importance in regulating biological processes and potential druggability. There have been many studies on the epigenetic regulation of ferroptosis, including histone modifications (e.g., histone acetylation and methylation), DNA methylation, and noncoding RNAs (e.g., miRNAs, circRNAs, and lncRNAs). In this review, we summarize recent advances in research on the epigenetic mechanisms involved in ferroptosis, with a description of RNA N6-methyladenosine (m6A) methylation included, and the importance of epigenetic regulation in biological processes and ferroptosis-related diseases, which provides reference for the clinical application of epigenetic regulators in the treatment of related diseases by targeting 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.

Targeting the p53 signaling pathway in cancers: Molecular mechanisms and clinical studies

Tumor suppressor p53 can transcriptionally activate downstream genes in response to stress, and then regulate the cell cycle, DNA repair, metabolism, angiogenesis, apoptosis, and other biological responses. p53 has seven functional domains and 12 splice isoforms, and different domains and subtypes play different roles. The activation and inactivation of p53 are finely regulated and are associated with phosphorylation/acetylation modification and ubiquitination modification, respectively. Abnormal activation of p53 is closely related to the occurrence and development of cancer. While targeted therapy of the p53 signaling pathway is still in its early stages and only a few drugs or treatments have entered clinical trials, the development of new drugs and ongoing clinical trials are expected to lead to the widespread use of p53 signaling-targeted therapy in cancer treatment in the future. TRIAP1 is a novel p53 downstream inhibitor of apoptosis. TRIAP1 is the homolog of yeast mitochondrial intermembrane protein MDM35, which can play a tumor-promoting role by blocking the mitochondria-dependent apoptosis pathway. This work provides a systematic overview of recent basic research and clinical progress in the p53 signaling pathway and proposes that TRIAP1 is an important therapeutic target downstream of p53 signaling.

p53 deacetylation alleviates calcium oxalate deposition-induced renal fibrosis by inhibiting ferroptosis

Calcium oxalate (CaOx) stones are among the most common types of kidney stones and are associated with renal tubular damage, interstitial fibrosis, and chronic kidney disease. The mechanism of CaOx crystal-induced renal fibrosis remains unknown. Ferroptosis, a type of regulated cell death, is characterised by iron-dependent lipid peroxidation, and the tumour suppressor p53 is a key regulator of ferroptosis. In the present study, our results demonstrated that ferroptosis was significantly activated in patients with nephrolithiasis and hyperoxaluric mice as well as verified the protective effects of ferroptosis inhibition on CaOx crystal-induced renal fibrosis. Moreover, the single-cell sequencing database, RNA-sequencing, and western blot analysis revealed that the expression of p53 was increased in patients with chronic kidney disease and the oxalate-stimulated human renal tubular epithelial cell line, HK-2. Additionally, the acetylation of p53 was enhanced by oxalate stimulation in HK-2 cells. Mechanistically, we found that the induction of p53 deacetylation, owing to either the SRT1720-induced activation of deacetylase sirtuin 1 or the triple mutation of p53, inhibited ferroptosis and alleviated renal fibrosis caused by CaOx crystals. We conclude that ferroptosis is one of the critical mechanisms contributing to CaOx crystal-induced renal fibrosis, and the pharmacological induction of ferroptosis via sirtuin 1-mediated p53 deacetylation may be a potential target for preventing renal fibrosis in patients with nephrolithiasis.

SIRT3 Deficiency Enhances Ferroptosis and Promotes Cardiac Fibrosis via p53 Acetylation

Cardiac fibrosis plays an essential role in the development of diastolic dysfunction and contributes to heart failure with preserved ejection fraction (HFpEF). Our previous studies suggested Sirtuin 3 (SIRT3) as a potential target for cardiac fibrosis and heart failure. In the present study, we explored the role of SIRT3 in cardiac ferroptosis and its contribution to cardiac fibrosis. Our data showed that knockout of SIRT3 resulted in a significant increase in ferroptosis, with increased levels of 4-hydroxynonenal (4-HNE) and downregulation of glutathione peroxidase 4 (GPX-4) in the mouse hearts. Overexpression of SIRT3 significantly blunted ferroptosis in response to erastin, a known ferroptosis inducer, in H9c2 myofibroblasts. Knockout of SIRT3 resulted in a significant increase in p53 acetylation. Inhibition of p53 acetylation by C646 significantly alleviated ferroptosis in H9c2 myofibroblasts. To further explore the involvement of p53 acetylation in SIRT3-mediated ferroptosis, we crossed acetylated p53 mutant (p534KR) mice, which cannot activate ferroptosis, with SIRT3KO mice. SIRT3KO/p534KR mice exhibited a significant reduction in ferroptosis and less cardiac fibrosis compared to SIRT3KO mice. Furthermore, cardiomyocyte-specific knockout of SIRT3 (SIRT3-cKO) in mice resulted in a significant increase in ferroptosis and cardiac fibrosis. Treatment of SIRT3-cKO mice with the ferroptosis inhibitor ferrostatin-1 (Fer-1) led to a significant reduction in ferroptosis and cardiac fibrosis. We concluded that SIRT3-mediated cardiac fibrosis was partly through a mechanism involving p53 acetylation-induced ferroptosis in myofibroblasts.

The Role of Histone Deacetylases in Acute Lung Injury-Friend or Foe

Acute lung injury (ALI), caused by intrapulmonary or extrapulmonary factors such as pneumonia, shock, and sepsis, eventually disrupts the alveolar-capillary barrier, resulting in diffuse pulmonary oedema and microatasis, manifested by refractory hypoxemia, and respiratory distress. Not only is ALI highly lethal, but even if a patient survives, there are also multiple sequelae. Currently, there is no better treatment than supportive care, and we urgently need to find new targets to improve ALI. Histone deacetylases (HDACs) are epigenetically important enzymes that, together with histone acetylases (HATs), regulate the acetylation levels of histones and non-histones. While HDAC inhibitors (HDACis) play a therapeutic role in cancer, inflammatory, and neurodegenerative diseases, there is also a large body of evidence suggesting the potential of HDACs as therapeutic targets in ALI. This review explores the unique mechanisms of HDACs in different cell types of ALI, including macrophages, pulmonary vascular endothelial cells (VECs), alveolar epithelial cells (AECs), and neutrophils.

GINS4 suppresses ferroptosis by antagonizing p53 acetylation with Snail

Ferroptosis is an iron-dependent oxidative, nonapoptotic form of regulated cell death caused by the destruction of redox homeostasis. Recent studies have uncovered complex cellular networks that regulate ferroptosis. GINS4 is a promoter of eukaryotic G1/S-cell cycle as a regulator of initiation and elongation of DNA replication, but little is known about its impact on ferroptosis. Here, we found that GINS4 was involved in the regulation of ferroptosis in lung adenocarcinoma (LUAD). CRISPR/Cas9-mediated GINS4 KO facilitated ferroptosis. Interestingly, depletion of GINS4 could effectively induce G1, G1/S, S, and G2/M cells to ferroptosis, especially for G2/M cells. Mechanistically, GINS4 suppressed p53 stability through activating Snail that antagonized the acetylation of p53, and p53 lysine residue 351 (K351 for human p53) was the key site for GINS4-suppressed p53-mediated ferroptosis. Together, our data demonstrate that GINS4 is a potential oncogene in LUAD that functions to destabilize p53 and then inhibits ferroptosis, providing a potential therapeutic target for LUAD.

p53-Dependent ferroptosis pathways in sepsis

Sepsis is caused by complex infections, trauma, and major surgery that results in high morbidity and mortality. As one of the leading causes of death in the intensive care unit (ICU）, sepsis causes organ dysfunction and death via a vicious cycle of uncontrolled inflammatory responses and immunosuppression. Ferroptosis is an iron-dependent cellular death pathway driven by the accumulation of lipid peroxides, which occurs in sepsis. p53 is an important regulator of ferroptosis. Under intracellular/extracellular stimulation and pressure, p53 acts as a transcription factor to regulate the expression of downstream genes, which help cells/bodies to resist stimuli. p53 can also function independently as an important mediator. The understanding of key cellular and molecular mechanisms of ferroptosis facilitates the prognosis of sepsis. This article describes the molecular mechanism and role of p53 in sepsis-induced ferroptosis, and introduces some potential therapeutic targets for sepsis-induced ferroptosis, which highlights the dominant and potential therapeutic role of p53 in sepsis. Keywords: p53, acetylation, Sirt3, ferroptosis, sepsis, therapy.

Zeaxanthin prevents ferroptosis by promoting mitochondrial function and inhibiting the p53 pathway in free fatty acid-induced HepG2 cells

Non-alcoholic fatty liver disease (NAFLD) is a common liver disorder worldwide and a risk factor for obesity and diabetes. Emerging evidence has shown that ferroptosis is involved in the progression of NAFLD. Zeaxanthin (ZEA) is a carotenoid found in human serum. It has been reported that ZEA can ameliorate obesity, prevent age-related macular degeneration, and protect against non-alcoholic steatohepatitis. However, no study has focused on the protective effects of ZEA against NAFLD. In this study, free fatty acid (FFA) induced HepG2 cells were used as a cell model for NAFLD. Our results suggest that ZEA exerts antioxidative and anti-inflammatory effects in FFA-induced HepG2 cells. Moreover, ZEA acted as a ferroptosis inhibitor, significantly reducing reactive oxygen species (ROS) generation and iron overload and improving mitochondrial dysfunction in FFA-induced HepG2 cells. In addition, ZEA downregulated the expression of p53 and modulated downstream targets, such as GPX4, SLC7A11, SAT1, and ALOX15, which contributed to the reduction in cellular lipid peroxidation. Our findings suggest that ZEA has the potential for NAFLD intervention.

Ferroptosis Regulated by Hypoxia in Cells

Ferroptosis is an oxidative damage-related, iron-dependent regulated cell death with intracellular lipid peroxide accumulation, which is associated with many physiological and pathological processes. It exhibits unique features that are morphologically, biochemically, and immunologically distinct from other regulated cell death forms. Ferroptosis is regulated by iron metabolism, lipid metabolism, anti-oxidant defense systems, as well as various signal pathways. Hypoxia, which is found in a group of physiological and pathological conditions, can affect multiple cellular functions by activation of the hypoxia-inducible factor (HIF) signaling and other mechanisms. Emerging evidence demonstrated that hypoxia regulates ferroptosis in certain cell types and conditions. In this review, we summarize the basic mechanisms and regulations of ferroptosis and hypoxia, as well as the regulation of ferroptosis by hypoxia in physiological and pathological conditions, which may contribute to the numerous diseases therapies.

The crosslinks between ferroptosis and autophagy in asthma

Autophagy is an evolutionarily conserved cellular process capable of degrading various biological molecules and organelles via the lysosomal pathway. Ferroptosis is a type of oxidative stress-dependent regulated cell death associated with the iron accumulation and lipid peroxidation. The crosslinks between ferroptosis and autophagy have been focused on since the dependence of ferroptosis on autophagy was discovered. Although the research and theories on the relationship between autophagy and ferroptosis remain scattered and fragmented, the crosslinks between these two forms of regulated cell death are closely related to the treatment of various diseases. Thereof, asthma as a chronic inflammatory disease has a tight connection with the occurrence of ferroptosis and autophagy since the crosslinked signal pathways may be the crucial regulators or exactly regulated by cells and secretion in the immune system. In addition, non-immune cells associated with asthma are also closely related to autophagy and ferroptosis. Further studies of cross-linking asthma inflammation with crosslinked signaling pathways may provide us with several key molecules that regulate asthma through specific regulators. The crosslinks between autophagy and ferroptosis provide us with a new perspective to interpret and understand the manifestations of asthma, potential drug discovery targets, and new therapeutic options to effectively intervene in the imbalance caused by abnormal inflammation in asthma. Herein, we introduce the main molecular mechanisms of ferroptosis, autophagy, and asthma, describe the role of crosslinks between ferroptosis and autophagy in asthma based on their common regulatory cells or molecules, and discuss potential drug discovery targets and therapeutic applications in the context of immunomodulatory and symptom alleviation.

Dihydroorotate dehydrogenase regulates ferroptosis in neurons after spinal cord injury via the P53-ALOX15 signaling pathway

BACKGROUND

Spinal cord injury (SCI) is a highly disabling condition in spinal surgery that leads to neuronal damage and secondary inflammation. Ferroptosis is a non-apoptotic type of cell death that has only recently been identified, which is marked primarily by iron-dependent and lipid-derived reactive oxygen species accumulation, and accompanied by morphological modifications such as mitochondrial atrophy and increase in membrane density. Dihydroorotate dehydrogenase (DHODH) is a powerful inhibitor of ferroptosis and has been demonstrated to inhibit cellular ferroptosis in tumor cells, but whether it can inhibit neuronal injury following spinal cord injury remains ambiguous.

METHODS

In this study, the effect of DHODH on neuronal ferroptosis was observed in vivo and in vitro using a rat spinal cord injury model and erastin-induced PC12 cells, respectively. A combination of molecular and histological approaches was performed to assess ferroptosis and explore the possible mechanisms in vivo and in vitro.

RESULTS

First, we confirmed the existence of neuronal ferroptosis after spinal cord injury and that DHODH attenuates neuronal damage after spinal cord injury. Second, we showed molecular evidence that DHODH inhibits the activation of ferroptosis-related molecules and reduces lipid peroxide production and mitochondrial damage, thereby reducing neuronal ferroptosis. Further analysis suggests that P53/ALOX15 may be one of the mechanisms regulated by DHODH. Importantly, we determined that DHODH inhibits ALOX15 expression by inhibiting P53.

CONCLUSIONS

Our findings reveal a novel function for DHODH in neuronal ferroptosis after spinal cord injury, suggesting a unique therapeutic target to alleviate the disease process of spinal cord injury.

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.

Targeting p53 pathways: mechanisms, structures, and advances in therapy

The TP53 tumor suppressor is the most frequently altered gene in human cancers, and has been a major focus of oncology research. The p53 protein is a transcription factor that can activate the expression of multiple target genes and plays critical roles in regulating cell cycle, apoptosis, and genomic stability, and is widely regarded as the "guardian of the genome". Accumulating evidence has shown that p53 also regulates cell metabolism, ferroptosis, tumor microenvironment, autophagy and so on, all of which contribute to tumor suppression. Mutations in TP53 not only impair its tumor suppressor function, but also confer oncogenic properties to p53 mutants. Since p53 is mutated and inactivated in most malignant tumors, it has been a very attractive target for developing new anti-cancer drugs. However, until recently, p53 was considered an "undruggable" target and little progress has been made with p53-targeted therapies. Here, we provide a systematic review of the diverse molecular mechanisms of the p53 signaling pathway and how TP53 mutations impact tumor progression. We also discuss key structural features of the p53 protein and its inactivation by oncogenic mutations. In addition, we review the efforts that have been made in p53-targeted therapies, and discuss the challenges that have been encountered in clinical development.

Ferroptosis: From Basic Research to Clinical Therapeutics in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common and highly heterogeneous malignancies worldwide. Despite the rapid development of multidisciplinary treatment and personalized precision medicine strategies, the overall survival of HCC patients remains poor. The limited survival benefit may be attributed to difficulty in early diagnosis, the high recurrence rate and high tumor heterogeneity. Ferroptosis, a novel mode of cell death driven by iron-dependent lipid peroxidation, has been implicated in the development and therapeutic response of various tumors, including HCC. In this review, we discuss the regulatory network of ferroptosis, describe the crosstalk between ferroptosis and HCC-related signaling pathways, and elucidate the potential role of ferroptosis in various treatment modalities for HCC, such as systemic therapy, radiotherapy, immunotherapy, interventional therapy and nanotherapy, and applications in the diagnosis and prognosis of HCC, to provide a theoretical basis for the diagnosis and treatment of HCC to effectively improve the survival of HCC patients.

P53 Acetylation Exerts Critical Roles In Pressure Overload Induced Coronary Microvascular Dysfunction and Heart Failure

Coronary microvascular dysfunction (CMD) has been shown to contribute to cardiac hypertrophy and heart failure with preserved ejection fraction. At this point, there are no proven treatments for CMD. We have shown that histone acetylation may play a critical role in the regulation of CMD. By using a mouse model that replaces lysine with arginine at residues K98/117/161/162R of p53 (p534KR), preventing acetylation at these sites, we test the hypothesis that acetylation-deficient p534KR could improve coronary microvascular dysfunction and prevent the progression of hypertensive cardiac hypertrophy and heart failure. Wild-type (WT) and p534KR mice were subjected to pressure overload (PO) by transverse aortic constriction to induce cardiac hypertrophy and heart failure (HF). Echocardiography measurements revealed improved cardiac function together with reduction of apoptosis and fibrosis in p534KR mice. Importantly, myocardial capillary density and coronary flow reserve (CFR) were significantly improved in p534KR mice. Moreover, p534KR upregulated the expression of cardiac glycolytic enzymes and glucose transporters, as well as the level of fructose-2,6-biphosphate; increased PFK-1 activity; and attenuated cardiac hypertrophy. These changes were accompanied by increased expression of HIF-1α and proangiogenic growth factors. Additionally, the levels of SERCA-2 were significantly upregulated in sham p534KR mice as well as in p534KR mice after TAC. In vitro, p534KR significantly improved endothelial cell (EC) glycolytic function and mitochondrial respiration, and enhanced EC proliferation and angiogenesis. Similarly, acetylation-deficient p534KR significantly improved CFR and rescued cardiac dysfunction in SIRT3 KO mice. Our data reveal the importance of p53 acetylation in coronary microvascular function, cardiac function, and remodeling, and may provide a promising approach to improve hypertension-induced coronary microvascular dysfunction (CMD) and to prevent the transition of cardiac hypertrophy to heart failure.

Tumor Suppressor p53 Down-Regulates Programmed Cell Death Protein 4 (PDCD4) Expression

The programmed cell death protein 4 (PDCD4), a well-known tumor suppressor, inhibits translation initiation and cap-dependent translation by inhibiting the helicase activity of EIF4A. The EIF4A tends to target mRNAs with a structured 5'-UTR. In addition, PDCD4 can also prevent tumorigenesis by inhibiting tumor promoter-induced neoplastic transformation, and studies indicate that PDCD4 binding to certain mRNAs inhibits those mRNAs' translation. A previous study demonstrated that PDCD4 inhibits the translation of p53 mRNA and that treatment with DNA-damaging agents down-regulates PDCD4 expression but activates p53 expression. The study further demonstrated that treatment with DNA-damaging agents resulted in the downregulation of PDCD4 expression and an increase in p53 expression, suggesting a potential mechanism by which p53 regulates the expression of PDCD4. However, whether p53 directly regulates PDCD4 remains unknown. Herein, we demonstrate for the first time that p53 regulates PDCD4 expression. Firstly, we found that overexpression of p53 in p53-null cells (H1299 and Saos2 cells) decreased the PDCD4 protein level. Secondly, p53 decreased PDCD4 promoter activity in gene reporter assays. Moreover, we demonstrated that mutations in p53 (R273H: contact hotspot mutation, and R175H: conformational hotspot mutation) abolished p53-mediated PDCD4 repression. Furthermore, mutations in the DNA-binding domain, but not in the C-terminal regulatory domain, of p53 disrupted p53-mediated PDCD4 repression. Finally, the C-terminal regulatory domain truncation study showed that the region between aa374 and aa370 is critical for p53-mediated PDCD4 repression. Taken together, our results suggest that p53 functions as a novel regulator of PDCD4, and the relationship between p53 and PDCD4 may be involved in tumor development and progression.

The Roles of Iron and Ferroptosis in Human Chronic Diseases

Ferroptosis, an iron-dependent novel type of cell death, has been characterized as an excessive accumulation of lipid peroxides and reactive oxygen species. A growing number of studies demonstrate that ferroptosis not only plays an important role in the pathogenesis and progression of chronic diseases, but also functions differently in different diseases. As a double-edged sword, activation of ferroptosis could potently inhibit tumor growth and increase sensitivity to chemotherapy and immunotherapy in various cancer settings. Therefore, the development of more efficacious ferroptosis agonists or inhibitors remains the mainstay of ferroptosis-targeting strategy for cancer therapeutics or cardiovascular and cerebrovascular diseases and neurodegenerative diseases therapeutics.

Review of ferroptosis in colorectal cancer: Friends or foes?

Ferroptosis is a newly discovered type of cell-regulated death. It is characterized by the accumulation of iron-dependent lipid peroxidation and can be distinguished from other forms of cell-regulated death by different morphology, biochemistry, and genetics. Recently, studies have shown that ferroptosis is associated with a variety of diseases, including liver, kidney and neurological diseases, as well as cancer. Ferroptosis has been shown to be associated with colorectal epithelial disorders, which can lead to cancerous changes in the gut. However, the potential role of ferroptosis in the occurrence and development of colorectal cancer (CRC) is still controversial. To elucidate the underlying mechanisms of ferroptosis in CRC, this article systematically reviews ferroptosis, and its cellular functions in CRC, for furthering the understanding of the pathogenesis of CRC to aid clinical treatment.

IRF8 Regulates Intrinsic Ferroptosis through Repressing p53 Expression to Maintain Tumor Cell Sensitivity to Cytotoxic T Lymphocytes

Ferroptosis has emerged as a cytotoxic T lymphocyte (CTL)-induced tumor cell death pathway. The regulation of tumor cell sensitivity to ferroptosis is incompletely understood. Here, we report that interferon regulatory factor 8 (IRF8) functions as a regulator of tumor cell intrinsic ferroptosis. Genome-wide gene expression profiling identified the ferroptosis pathway as an IRF8-regulated pathway in tumor cells. IRF8.KO tumor cells acquire resistance to intrinsic ferroptosis induction and IRF8-deficient tumor cells also exhibit decreased ferroptosis in response to tumor-specific CTLs. Irf8 deletion increased p53 expression in tumor cells and knocking out p53 in IRF8.KO tumor cells restored tumor cell sensitivity to intrinsic ferroptosis induction. Furthermore, IRF8.KO tumor cells grew significantly faster than WT tumor cells in immune-competent mice. To restore IRF8 expression in tumor cells, we designed and synthesized codon usage-optimized IRF8-encoding DNA to generate IRF8-encoding plasmid NTC9385R-mIRF8. Restoring IRF8 expression via a lipid nanoparticle-encapsulated NTC9385R-mIRF8 plasmid therapy suppressed established tumor growth in vivo. In human cancer patients, nivolumab responders have a significantly higher IRF8 expression level in their tumor cells as compared to the non-responders. Our data determine that IRF8 represses p53 expression to maintain tumor cell sensitivity to intrinsic ferroptosis.

Identification of a Novel Ferroptosis-Related Gene Signature for Predicting Prognosis and Responsiveness to Immunotherapy in Hepatocellular Carcinoma

Purpose

Ferroptosis has been reported to regulate multiple biological behaviors. However, the prognostic and oncologic values of ferroptosis-related genes (FRGs) have not been comprehensively elucidated in hepatocellular carcinoma (HCC). Here, we aimed to construct FRGs-associated signature for stratification of the prognosis of HCC patients.

Methods

A list of FRGs was generated from FerrDb. Public databases were used to extract expression matrices and clinical information. TCGA cohort was randomly divided into a training set and a validation set. Prognostic signature for Overall Survival (OS) was established in training set and validated in internal cohorts (TCGA validation set and entire set) and external cohort (ICGC cohort). Additionally, the role of signature in HCC was well investigated by analysis of mutations, gene set enrichment analysis (GSEA), analysis of immune infiltrates, and analysis of response to immune checkpoint blockade (ICB) treatment. The oncogenic effects of ZFP69B on HCC were also investigated in vitro.

Results

We identified 12 FRGs-based signature for OS with LASSO regression. Patients were partitioned into different risk groups based on the signature. Overall, patients in different groups had different prognosis. The signature independently predicted OS in multivariate Cox regression analyses. Anti-tumor immune cells including activated CD8 T cells, cytolytic activity, and Th1 cells were negatively correlated with risk score in both TCGC and ICGC cohorts. Furthermore, low-risk patients responded better to ICB than high-risk patients. In addition, knockdown of ZFP69B reduced proliferation, migration, and invasion, and promoted erastin-induced ferroptosis of HCC cells.

Conclusion

We developed a prognostic signature based on FRGs to predict OS of HCC patients. And the signature may facilitate clinicians in identifying those who are likely to benefit from ICIs. The results also indicated that ZFP69B might regulate the process of ferroptosis and could be used as a novel potential target for HCC.

Ferroptosis: mechanisms and advances in ocular diseases

As an essential trace element in the body, iron is critical for the maintenance of organismal metabolism. Excessive iron facilitates reactive oxygen species generation and inflicts damage on cells and tissues. Ferroptosis, a newly identified iron-dependent type of programmed cell death, has been implicated in a broad set of metabolic disorders. Ferroptosis is mainly characterized by excess iron accumulation, elevated lipid peroxides and reactive oxygen species, and reduced levels of glutathione and glutathione peroxidase 4. The vast emerging literature on ferroptosis has shown that numerous diseases, such as cancers, neurodegeneration, and autoimmune diseases, are associated with ferroptosis. Meanwhile, recent studies have confirmed the relationship between ferroptosis and eye diseases including keratopathy, cataract, glaucoma, retinal ischemia-reperfusion injury, age-related macular degeneration, retinitis pigmentosa, diabetic retinopathy, and retinoblastoma, indicating the critical role of ferroptosis in ocular diseases. In this article, we introduce the primary signaling pathways of ferroptosis and review current advances in research on ocular diseases involving iron overload and ferroptosis. Furthermore, several unanswered questions in the area are raised. Addressing these unanswered questions promises to provide new insights into preventing, controlling, and treating not only ocular diseases but also a variety of other diseases in the near future.

Effect of regulatory cell death on the occurrence and development of head and neck squamous cell carcinoma

Head and neck cancer is a malignant tumour with a high mortality rate characterized by late diagnosis, high recurrence and metastasis rates, and poor prognosis. Head and neck squamous cell carcinoma (HNSCC) is the most common type of head and neck cancer. Various factors are involved in the occurrence and development of HNSCC, including external inflammatory stimuli and oncogenic viral infections. In recent years, studies on the regulation of cell death have provided new insights into the biology and therapeutic response of HNSCC, such as apoptosis, necroptosis, pyroptosis, autophagy, ferroptosis, and recently the newly discovered cuproptosis. We explored how various cell deaths act as a unique defence mechanism against cancer emergence and how they can be exploited to inhibit tumorigenesis and progression, thus introducing regulatory cell death (RCD) as a novel strategy for tumour therapy. In contrast to accidental cell death, RCD is controlled by specific signal transduction pathways, including TP53 signalling, KRAS signalling, NOTCH signalling, hypoxia signalling, and metabolic reprogramming. In this review, we describe the molecular mechanisms of nonapoptotic RCD and its relationship to HNSCC and discuss the crosstalk between relevant signalling pathways in HNSCC cells. We also highlight novel approaches to tumour elimination through RCD.

Ferroptosis: Mechanism and potential applications in cervical cancer

Ferroptosis is a distinct form of cell death mechanism different from the traditional ones. Ferroptosis is characterized biochemically by lipid peroxidation, iron accumulation, and glutathione deficiency. It has already demonstrated significant promise in antitumor therapy. Cervical cancer (CC) progression is closely linked to iron regulation and oxidative stress. Existing research has investigated the role of ferroptosis in CC. Ferroptosis could open up a new avenue of research for treating CC. This review will describe the factors and pathways and the research basis of ferroptosis, which is closely related to CC. Furthermore, the review may provide potential future directions for CC research, and we believe that more studies concerning the therapeutic implications of ferroptosis in CC will come to notice.

Protein acylation: mechanisms, biological functions and therapeutic targets

Metabolic reprogramming is involved in the pathogenesis of not only cancers but also neurodegenerative diseases, cardiovascular diseases, and infectious diseases. With the progress of metabonomics and proteomics, metabolites have been found to affect protein acylations through providing acyl groups or changing the activities of acyltransferases or deacylases. Reciprocally, protein acylation is involved in key cellular processes relevant to physiology and diseases, such as protein stability, protein subcellular localization, enzyme activity, transcriptional activity, protein-protein interactions and protein-DNA interactions. Herein, we summarize the functional diversity and mechanisms of eight kinds of nonhistone protein acylations in the physiological processes and progression of several diseases. We also highlight the recent progress in the development of inhibitors for acyltransferase, deacylase, and acylation reader proteins for their potential applications in drug discovery.

Inhibition of TIGAR Increases Exogenous p53 and Cisplatin Combination Sensitivity in Lung Cancer Cells by Regulating Glycolytic Flux

The metabolism and apoptosis of tumor cells are important factors that increase their sensitivity to chemotherapeutic drugs. p53 and cisplatin not only induce tumor cell apoptosis, but also regulate the tumor cell metabolism. The TP53-induced glycolysis and apoptosis regulator (TIGAR) can inhibit glycolysis and promote more glucose metabolism in the pentose phosphate pathway. We speculate that the regulation of the TIGAR by the combination therapy of p53 and cisplatin plays an important role in increasing the sensitivity of tumor cells to cisplatin. In this study, we found that the combined treatment of p53 and cisplatin was able to inhibit the mitochondrial function, promote mitochondrial pathway-induced apoptosis, and increase the sensitivity. Furthermore, the expression of the TIGAR was inhibited after a combined p53 and cisplatin treatment, the features of the TIGAR that regulate the pentose phosphate pathway were inhibited, the glucose flux shifted towards glycolysis, and the localization of the complex of the TIGAR and Hexokinase 2 (HK2) on the mitochondria was also reduced. Therefore, the combined treatment of p53 and cisplatin may modulate a glycolytic flux through the TIGAR, altering the cellular metabolic patterns while increasing apoptosis. Taken together, our findings reveal that the TIGAR may serve as a potential therapeutic target to increase the sensitivity of lung cancer A549 cells to cisplatin.

SLC7A11 as a Gateway of Metabolic Perturbation and Ferroptosis Vulnerability in Cancer

SLC7A11 is a cell transmembrane protein composing the light chain of system xc^-, transporting extracellular cystine into cells for cysteine production and GSH biosynthesis. SLC7A11 is a critical gateway for redox homeostasis by maintaining the cellular levels of GSH that counter cellular oxidative stress and suppress ferroptosis. SLC7A11 is overexpressed in various human cancers and regulates tumor development, proliferation, metastasis, microenvironment, and treatment resistance. Upregulation of SLC7A11 in cancers is needed to adapt to high oxidative stress microenvironments and maintain cellular redox homeostasis. High basal ROS levels and SLC7A11 dependences in cancer cells render them vulnerable to further oxidative stress. Therefore, cyst(e)ine depletion may be an effective new strategy for cancer treatment. However, the effectiveness of the SLC7A11 inhibitors or cyst(e)inase has been established in many preclinical studies but has not reached the stage of clinical trials for cancer patients. A better understanding of cysteine and SLC7A11 functions regulating and interacting with redox-active proteins and their substrates could be a promising strategy for cancer treatment. Therefore, this review intends to understand the role of cysteine in antioxidant and redox signaling, the regulators of cysteine bioavailability in cancer, the role of SLC7A11 linking cysteine redox signaling in cancer metabolism and targeting SLC7A11 for novel cancer therapeutics.

A PARP1 PROTAC as a novel strategy against PARP inhibitor resistance via promotion of ferroptosis in p53-positive breast cancer

Therapeutic targeting of the nuclear enzyme poly (ADP-ribose) polymerase 1 (PARP1) with PARP inhibitors (PARPis) in patients with a homologous recombination (HR)- deficient phenotype based on the mechanism of synthetic lethality has been shown tremendous success in cancer therapy. With the clinical use of various PARPis, emerging evidence has shown that some PARPis offer hope for breakthroughs in triple-negative breast cancer (TNBC) therapy, regardless of HR status. However, similar to other conventional cytotoxic drugs, PARPis are also subject to the intractable problem of drug resistance. Notably, acquired resistance to PARPis caused by point mutations in the PARP1 protein is hard to overcome with current strategies. To explore modalities to overcome resistance and identify patients who are most likely to benefit from PARP1-targeted therapy, we developed a proteolysis-targeted chimaera (PROTAC) to degrade mutant PARP1 in TNBC. Here, we investigated a PARP1 PROTAC termed "NN3″, which triggered ubiquitination and proteasome-mediated degradation of PARP1. Moreover, NN3 degraded PARP1 with resistance-related mutations. Interestingly, compared with other reported PARP1 degraders, NN3 exhibited a unique antitumor mechanism in p53-positive breast cancer cells that effectively promoted ferroptosis by downregulating the SLC7A11 pathway. Furthermore, NN3 showed potent activity and low toxicity in vivo. In conclusion, we propose PROTAC-mediated degradation of PARP1 as a novel strategy against mutation-related PARPi resistance and a paradigm for targeting breast cancer with functional p53 via ferroptosis induction.

Diabetic Ferroptosis and Pancreatic Cancer: Foe or Friend?

Significance: Pancreatic cancer and diabetes have a reciprocal causation relationship. As a potential risk factor, diabetes increases morbidity and promotes pancreatic cancer progression. The main mechanisms include islet dysfunction-induced systemic metabolic disorder, pancreatic stellate cell activation, and immunosuppression. Ferroptosis is regarded as regulated cell death, which participates in chemotherapy resistance and is refractory to radiation therapy and immunotherapy. Diabetes-induced ferroptosis causes many complications, but the underlying mechanism of diabetes-related ferroptosis in pancreatic cancer has not been discussed. Recent Advances: Ferroptosis alleviates pancreatic intraepithelial neoplasia (PanIN) progression by activating chronic inflammation. The specific drugs that cause ferroptosis achieve tumor suppression by inducing lipid peroxidation. Ferroptosis plays pro and con roles in cancer. Both the ferroptosis inhibitor and inducer exhibit antitumor effects through killing cancer cells or directly affecting tumor growth. Diabetes-induced ferroptosis contributes to tumor cell death by different components, including tumor cells, fibroblasts, immune cells, and adipocytes. A better understanding of its role in modulating the tumor microenvironment will reveal diabetes-associated ferroptotic features in cancer development, which can be used to figure out possible treatment strategies for cancer patients with hyperglycemia. Critical Issues: We demonstrate the potential roles of diabetes-related ferroptosis in pancreatic cancer progression and discuss ferroptosis-related antitumor effects and therapeutics for pancreatic cancer treatment. Future Directions: Further studies are required to highlight mechanisms of diabetes-mediated ferroptosis in pancreatic cancer tumorigenesis and progression. The antitumor effects of ferroptosis regulators combined with chemotherapy, targeted therapy, or immunotherapy in diabetic patients should be investigated. We hope that pancreatic cancer patients with diabetes will benefit from ferroptosis-related therapies. Antioxid. Redox Signal. 37, 1206-1221.

Insights into Regulators of p53 Acetylation

The tumor suppressor p53 is a transcription factor that regulates the expression of dozens of target genes and diverse physiological processes. To precisely regulate the p53 network, p53 undergoes various post-translational modifications and alters the selectivity of target genes. Acetylation plays an essential role in cell fate determination through the activation of p53. Although the acetylation of p53 has been examined, the underlying regulatory mechanisms remain unclear and, thus, have attracted the interest of researchers. We herein discuss the role of acetylation in the p53 pathway, with a focus on p53 acetyltransferases and deacetylases. We also review recent findings on the regulators of these enzymes to understand the mode of p53 acetylation from a broader perspective.

Inducing ferroptosis has the potential to overcome therapy resistance in breast cancer

Breast cancer is the most common type of malignancy among women. Due to the iron-dependent character of breast cancer cells, they are more sensitive to ferroptosis compared to normal cells. It is possible to reverse tumor resistance by inducing ferroptosis in breast cancer cells, thereby improving tumor treatment outcomes. Ferroptosis is highly dependent on the balance of oxidative and antioxidant status. When ferroptosis occurs, intracellular iron levels are significantly increased, leading to increased membrane lipid peroxidation and ultimately triggering ferroptosis. Ferroptotic death is a form of autophagy-associated cell death. Synergistic use of nanoparticle-loaded ferroptosis-inducer with radiotherapy and chemotherapy achieves more significant tumor suppression and inhibits the growth of breast cancer by targeting cancer tissues, enhancing the sensitivity of cells to drugs, reducing the drug resistance of cancer cells and the toxicity of drugs. In this review, we present the current status of breast cancer and the mechanisms of ferroptosis. It is hopeful for us to realize effective treatment of breast cancer through targeted ferroptosis.

The Underestimated Role of the p53 Pathway in Renal Cancer

The TP53 tumor suppressor gene is known as the guardian of the genome, playing a pivotal role in controlling genome integrity, and its functions are lost in more than 50% of human tumors due to somatic mutations. This percentage rises to 90% if mutations and alterations in the genes that code for regulators of p53 stability and activity are taken into account. Renal cell carcinoma (RCC) is a clear example of cancer that despite having a wild-type p53 shows poor prognosis because of the high rate of resistance to radiotherapy or chemotherapy, which leads to recurrence, metastasis and death. Remarkably, the fact that p53 is poorly mutated does not mean that it is functionally active, and increasing experimental evidences have demonstrated this. Therefore, RCC represents an extraordinary example of the importance of p53 pathway alterations in therapy resistance. The search for novel molecular biomarkers involved in the pathways that regulate altered p53 in RCC is mandatory for improving early diagnosis, evaluating the prognosis and developing novel potential therapeutic targets for better RCC treatment.

The Four Homeostasis Knights: In Balance upon Post-Translational Modifications

A cancer outcome is a multifactorial event that comes from both exogenous injuries and an endogenous predisposing background. The healthy state is guaranteed by the fine-tuning of genes controlling cell proliferation, differentiation, and development, whose alteration induces cellular behavioral changes finally leading to cancer. The function of proteins in cells and tissues is controlled at both the transcriptional and translational level, and the mechanism allowing them to carry out their functions is not only a matter of level. A major challenge to the cell is to guarantee that proteins are made, folded, assembled and delivered to function properly, like and even more than other proteins when referring to oncogenes and onco-suppressors products. Over genetic, epigenetic, transcriptional, and translational control, protein synthesis depends on additional steps of regulation. Post-translational modifications are reversible and dynamic processes that allow the cell to rapidly modulate protein amounts and function. Among them, ubiquitination and ubiquitin-like modifications modulate the stability and control the activity of most of the proteins that manage cell cycle, immune responses, apoptosis, and senescence. The crosstalk between ubiquitination and ubiquitin-like modifications and post-translational modifications is a keystone to quickly update the activation state of many proteins responsible for the orchestration of cell metabolism. In this light, the correct activity of post-translational machinery is essential to prevent the development of cancer. Here we summarize the main post-translational modifications engaged in controlling the activity of the principal oncogenes and tumor suppressors genes involved in the development of most human cancers.

The roles of lncRNA functions and regulatory mechanisms in the diagnosis and treatment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most frequent and deadly type of liver cancer. While the underlying molecular mechanisms are poorly understood, it is documented that lncRNAs may play key roles. Many HCC-associated lncRNAs have been linked to HBV and HCV infection, mediating gene expression, cell growth, development, and death. Studying the regulatory mechanisms and biological functions of HCC-related lncRNAs will assist our understanding of HCC pathogenesis as well as its diagnosis and management. Here, we address the potential of dysregulated lncRNAs in HCC as diagnostic and therapeutic biomarkers, and we evaluate the oncogenic or tumor-suppressive properties of these lncRNAs.

Mutant p53 in cancer: from molecular mechanism to therapeutic modulation

TP53, a crucial tumor suppressor gene, is the most commonly mutated gene in human cancers. Aside from losing its tumor suppressor function, mutant p53 (mutp53) often acquires inherent, novel oncogenic functions, which is termed "gain-of-function". Emerging evidence suggests that mutp53 is highly associated with advanced malignancies and poor prognosis, which makes it a target for development of novel cancer therapies. Herein, we provide a summary of our knowledge of the mutp53 types and mutp53 spectrum in cancers. The mechanisms of mutp53 accumulation and gain-of-function are also summarized. Furthermore, we discuss the gain-of-function of mutp53 in cancers: genetic instability, ferroptosis, microenvironment, and stemness. Importantly, the role of mutp53 in the clinic is also discussed, particularly with regard to chemotherapy and radiotherapy. Last, emphasis is given to emerging strategies on how to target mutp53 for tumor therapy. Thus, this review will contribute to better understanding of the significance of mutp53 as a target for therapeutic strategies.

The role of TIGAR in nervous system diseases

TP53-induced glycolysis and apoptosis regulator (TIGAR) mainly regulates pentose phosphate pathway by inhibiting glycolysis, so as to synthesize ribose required by DNA, promote DNA damage repair and cell proliferation, maintain cell homeostasis and avoid body injury. Its physiological functions include anti-oxidative stress, reducing inflammation, maintaining mitochondrial function, inhibiting apoptosis, reducing autophagy etc. This paper reviews the research of TIGAR in neurological diseases, including stroke, Parkinson’s disease (PD), Alzheimer’s disease (AD), seizures and brain tumors, aiming to provide reference for the development of new therapeutic targets.

Phytochemicals Targeting Ferroptosis: Therapeutic Opportunities and Prospects for Treating Breast Cancer

Ferroptosis, a recently discovered iron-dependent regulated cell death, has been implicated in the therapeutic responses of various cancers including breast cancer, making it a promising therapeutic target to manage this malignancy. Phytochemicals are conventional sources for medication development. Some phytochemicals have been utilized therapeutically to treat cancers as pharmaceutic agents or dietary supplements. Intriguingly, a considerable number of antitumor drugs derived from phytochemicals have been proven to be targeting ferroptosis, thus producing anticancer effects. In this review, we provide a short overview of the interaction between core ferroptosis modulators and breast cancer, illustrating how ferroptosis affects the destiny of breast cancer cells. We also systematically summarize the regulatory effects of phytochemicals on ferroptosis and emphasize their clinical applications in breast cancer suppression, which may accelerate the development of their therapeutic use in breast cancer.

Identification of Molecular Markers Related to Immune Infiltration in Patients with Severe Asthma: A Comprehensive Bioinformatics Analysis Based on the Human Bronchial Epithelial Transcriptome

Background. Severe asthma (SA), a heterogeneous inflammatory disease characterized by immune cell infiltration, is particularly difficult to treat and manage. The airway epithelium is an important tissue in regulating innate and adaptive immunity, and targeting airway epithelial cell may contribute to improving the efficacy of asthma therapy. Methods. Bioinformatics methods were utilized to identify the hub genes and signaling pathways involved in SA. Experiments were performed to determine whether these hub genes and signaling pathways were affected by the differences in immune cell infiltration. Results. The weighted gene coexpression network analysis identified 14 coexpression modules, among which the blue and salmon modules exhibited the strongest associations with SA. The blue module was mainly enriched in actomyosin structure organization and was associated with regulating stem cell pluripotency signaling pathways. The salmon module was mainly involved in cornification, skin development, and glycosphingolipid biosynthesis-lacto and neolacto series. The protein-protein interaction network and module analysis identified 11 hub genes in the key modules. The CIBERSORTx algorithm revealed statistically significant differences in CD8+ T cells ( $P=0.013$ ), T follicular helper cells ( $P=0.002$ ), resting mast cells ( $P=0.004$ ), and neutrophils ( $P=0.002$ ) between patients with SA and mild-moderate asthma patients. Pearson’s correlation analysis identified 11 genes that were significantly associated with a variety of immune cells. We further predicted the utility of some potential drugs and validated our results in external datasets. Conclusion. Our results may help provide a better understanding of the relationship between the airway epithelial transcriptome and clinical data of SA. And this study will help to guide the development of SA-targeted molecular therapy.