Non-enzymatic lipid peroxidation initiated by photodynamic therapy drives a distinct ferroptosis-like cell death pathway

Ferroptosis: when metabolism meets cell death

We present here a comprehensive update on recent advancements in the field of ferroptosis, with a particular emphasis on its metabolic underpinnings and physiological impacts. After briefly introducing landmark studies that have helped to shape the concept of ferroptosis as a distinct form of cell death, we critically evaluate the key metabolic determinants involved in its regulation. These include the metabolism of essential trace elements such as selenium and iron; amino acids such as cyst(e)ine, methionine, glutamine/glutamate, and tryptophan; and carbohydrates, covering glycolysis, the citric acid cycle, the electron transport chain, and the pentose phosphate pathway. We also delve into the mevalonate pathway and subsequent cholesterol biosynthesis, including intermediate metabolites like dimethylallyl pyrophosphate, squalene, coenzyme Q (CoQ), vitamin K, and 7-dehydrocholesterol, as well as fatty acid and phospholipid metabolism, including the biosynthesis and remodeling of ester and ether phospholipids and lipid peroxidation. Next, we highlight major ferroptosis surveillance systems, specifically the cyst(e)ine/glutathione/glutathione peroxidase 4 axis, the NAD(P)H/ferroptosis suppressor protein 1/CoQ/vitamin K system, and the guanosine triphosphate cyclohydrolase 1/tetrahydrobiopterin/dihydrofolate reductase axis. We also discuss other potential anti- and proferroptotic systems, including glutathione S-transferase P1, peroxiredoxin 6, dihydroorotate dehydrogenase, glycerol-3-phosphate dehydrogenase 2, vitamin K epoxide reductase complex subunit 1 like 1, nitric oxide, and acyl-CoA synthetase long-chain family member 4. Finally, we explore ferroptosis's physiological roles in aging, tumor suppression, and infection control, its pathological implications in tissue ischemia-reperfusion injury and neurodegeneration, and its potential therapeutic applications in cancer treatment. Existing drugs and compounds that may regulate ferroptosis in vivo are enumerated.

Hypericin mediated photodynamic therapy induces ferroptosis via inhibiting the AKT/mTORC1/GPX4 axis in cholangiocarcinoma

Cholangiocarcinoma remains a challenging primary hepatobiliary malignancy with dismal prognosis. Photodynamic therapy (PDT),a less invasive treatment, has been found to inhibit the proliferation and induce ferroptosis, apoptosis and necrosis in other tumor cells in recent years. Regrettably, the role and exact molecule mechanism of PDT is still incompletely clear in cholangiocarcinoma cells. Ferroptosis is a novel regulated cell death(RCD), which is controlled by glutathione peroxidase4(GPX4) with the characteristics of iron dependent and excessive intracellular accumulation of lipid peroxides. This novel form of RCD has attracted great attention as a potential new target in clinical oncology during recent years. In this study, we observed that hypericin mediated PDT(HY-PDT) could significantly inhibit the proliferation of the cholangiocarcinoma cells and suppress migration and the epithelial mesenchymal transition (EMT) as well. Then, we conducted transcriptome sequencing and bioinformatics analysis and observed that HY-PDT was most likely involved in ferroptosis, apoptosis, the EMT process and AKT/mTORC1 signaling pathways in cholangiocarcinoma cells. Next, a series of in vitro and in vivo experiments were performed to confirm that HY-PDT could trigger cholangiocarcinoma cells ferroptosis through inhibiting the expression of GPX4 protein. In terms of molecular mechanism, we found that HY-PDT induced ferroptosis by decreasing GPX4 expression via suppression of the AKT/mTORC1 signaling pathway. In addition, we also found that HY-PDT inhibit cholangiocarcinoma cells migration and the EMT process by inhibiting the AKT/mTORC1 pathway. Our study illustrated a new mechanism of action for HY-PDT and might throw light on the individualized precision therapy for cholangiocarcinoma patients.

Mannose functionalized small molecule nanodrug self-assembled from amphiphilic prodrug connected by disulfide bonds for synergistic cancer chemotherapy and photodynamic/photothermal therapy

Compared to conventional nanocarrier-based drug delivery technology, small-molecule-assembled nanomaterials provide various advantages, including higher drug loading efficiency, lower excipient-related toxicity, and a simpler formulation process. Our research constructed a mannonse-modified small-molecule-assembled nanodrug for synergistic photodynamic/chemotherapy against A549 cancer cells. The hydrophobic hypoxic-activated agent tirapazamine (TPZ) and a hydrophilic fluorescence probe Cyanine 3 (Cy3) constitute this amphiphilic prodrug via a glutathione (GSH)-responsive linkage, which could self-assemble into stable nanoparticles (NPs) and encapsulate a newly synthesized photosensitizer (SeBDP). To enhance the tumor targeting capability, we introduced a tumor-targeted nanodrug SeBDP@TPZ-S-S-Cy/Man NPs by co-assembling mannose-modified lipid (DSPE-PEG-Man). The GSH-responsive linkage of TPZ-S-S-Cy can be rapidly cleaved by GSH to release the therapeutic agents and fluorescent molecule. The released SeBDP generate reactive oxygen species (ROS) to specifically kill cancer cells and elevate hypoxia, thereby enhancing the cytotoxicity of TPZ. SeBDP@TPZ-S-S-Cy/Man NPs exhibited high selectivity and efficiency for in vivo combination therapy without adverse effects to normal tissues. Our findings demonstrate that SeBDP@TPZ-S-S-Cy/Man NPs have great potential for enhancing cancer treatment both in vitro and in vivo by combining an oxygen depletion prodrug with a hypoxia-activated antitumor agent. Thus, the GSH-sensitive self-assembled nanodrug from an amphiphilic hypoxia-activated prodrug, could serve as a potential drug carrier in targeted synergistic cancer therapy.

Validation and the role of PDK4 relevant to ferroptosis in degenerative lumbar disc disease

BACKGROUND

Ferroptosis was involved in the pathogenesis of intervertebral disc degeneration (IVDD). However, the exact mechanism of IVDD associated with ferroptosis still required deeper studies.

METHOD

The differentially expressed genes (DEGs) in rat lumbar disc tissue between the control and IVDD group treated with IL-1β were detected by RNA sequencing (RNA-seq). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed on DEGs. We further screened the differential expressed ferroptosis-related genes (DEFRGs). Besides, a protein-protein interaction (PPI) network of DEFRGs was constructed by STRING database. The Cytoscape database identified significant modules and the hub genes. The loss function of PDK4 by siRNA inference was investigated in NPCs by CCK8 assay, ELISA assay, and the analysis of ferroptosis indicators.

RESULT

DEGs were identified using RNA-seq. KEGG pathway analysis showed that these genes were mainly involved in Parkinson's disease, oxytocin signaling pathway, calcium ion signaling pathway, AMPK signaling pathway, and glucagon signaling pathway. Eight hub genes (including LDHA, PKM, EP300, EGFR, EGLN1, SCD, PDK4, and FABP4) were found by the PPI network and Cytoscape on a total of 25 ferroptosis-related genes that were identified in rat lumbar disc tissue after IVDD treatment. PDK4 silencing promoted NPCS proliferation, decreased the levels of the proinflammatory factors, and suppressed ferroptosis.

CONCLUSION

The study suggested the potential roles of ferroptosis-related genes in IVDD and further revealed the role of PDK4 in the progression of IVDD.

Identification of fatty acid anabolism patterns to predict prognosis and immunotherapy response in gastric cancer

Gastric cancer (GC), one of the most common and heterogeneous malignancies, is the second leading cause of cancer death worldwide and is closely related to dietary habits. Fatty acid is one of the main nutrients of human beings, which is closely related to diabetes, hypertension and other diseases. However, the correlation between fatty acid metabolism and the development and progression of GC remains largely unknown. Here, we profiled the genetic alterations of fatty acid anabolism-related genes (FARGs) in gastric cancer samples from the TCGA cohort and GEO database to evaluate the possible relationships and their internal regulatory mechanism. Through consistent clustering and functional enrichment analysis, three distinct fatty acid anabolism clusters and three gene subtypes were identified to participate in different biological pathways, and correlated with the characteristics of immune cell infiltration and clinical prognosis. Importantly, a distinctive FA-score was constructed through the principal component analysis to quantify the characteristics of fatty acid anabolism in each GC patient. Further analysis showed patients grouped in the high FA-score group were characterized with greater tumor mutational burden (TMB) and higher microsatellite stability (MSI-H), which may be more aeschynomenous to immunotherapy and had a favorable prognosis. Altogether, our bioinformatics analysis based on FARGs uncovered the potential roles of fatty acid metabolism in GC, and may provide newly prognostic information and novel approaches for promoting individualized immunotherapy in patients with GC.

Photodynamic therapy photosensitizers and photoactivated chemotherapeutics exhibit distinct bioenergetic profiles to impact ATP metabolism

Energy is essential for all life, and mammalian cells generate and store energy in the form of ATP by mitochondrial (oxidative phosphorylation) and non-mitochondrial (glycolysis) metabolism. These processes can now be evaluated by extracellular flux analysis (EFA), which has proven to be an indispensable tool in cell biology, providing previously inaccessible information regarding the bioenergetic landscape of cell lines, complex tissues, and in vivo models. Recently, EFA demonstrated its utility as a screening tool in drug development, both by providing insights into small molecule-organelle interactions, and by revealing the peripheral and potentially undesired off-target effects small molecules have within cells. Surprisingly, technologies to quantify cellular bioenergetics have not been systematically applied in phototherapy development, leaving open several questions about how the mechanism of action of a compound can impact essential cellular functions. Here, we utilized the Seahorse analyzer to address this question for photosensitizers (PSs) for photodynamic therapy (PDT) and contrast these systems to molecules that photo-release a ligand and thus act as photocages or photoactivated chemotherapeutics (PACT), intending to understand the influence these two classes of compounds have on cellular bioenergetics. EFA results show that acute treatment of A549 lung adenocarcinoma cells with PDT agents induces a quiescent bioenergetic response as a result of mitochondrial respiration shutdown. The loss of oxidative phosphorylation is followed by disruption of glycolysis, which occurs after an initial increase in glycolytic respiration is unable to compensate for the interruption of the electron transport chain (ETC). In contrast, the PACT agents tested had little impact on cellular respiration, and the minor inhibition of these metabolic processes was not related to the mechanism of action, as reflected by a lack of correlation with photoejection efficiency. Notably, a system capable of both generating 1O2 and photo-releasing a ligand exhibited the dominant profile of a PDT agent and induced the quiescent bioenergetic state, indicating potential implications on cellular bioenergetics for so-called dual-action agents. These findings are presented with the aim to provide the necessary groundwork for expanding the application and utility of EFA to phototherapeutics and to highlight the role of metabolic alterations in PDT.

Recent Advances in Nanomaterial-Mediated Cell Death for Cancer Therapy

Nanomedicine has shown great anticancer potential by disrupting redox homeostasis and increasing the levels of oxidative stress, but the therapeutic effect is limited by factors including the intrinsic self-protection mechanism of tumors. Cancer cell death can be induced by the exploration of different cell death mechanisms, such as apoptosis, pyroptosis, necroptosis, cuproptosis, and ferroptosis. The merging of nanotechnology with biomedicine has provided tremendous opportunities to construct cell death-based nanomedicine for innovative cancer therapy. Nanocarriers are not only used for the targeted delivery of cell death inducers, but also as therapeutic components to induce cell death to achieve efficient tumor treatment. This review focuses on seven cell death modalities mediated by nanomaterials, such as apoptosis, pyroptosis, necroptosis, ferroptosis, cuprotosis, immunogenic cell death, and autophagy. The mechanisms of these seven cell death modalities are described in detail, as well as the preparation of nanomaterials that induce them and the mechanisms, they used to exert their effects. Finally, this work describes the potential future development based on the current knowledge related to cell death induced by nanomaterials.

Evaluation of indocyanine green antimicrobial photodynamic therapy in radical species elimination: an in vitro study

INTRODUCTION

Antimicrobial photodynamic therapy (aPDT) utilizes light-sensitive materials to inactivate pathogens. Indocyanine green (ICG) is an FDA-approved photosensitizer known for its effective photo-thermal and photo-chemical properties.

Ferroptosis: A novel cell death modality as a synergistic therapeutic strategy with photodynamic therapy

Although there has been significant progress in current comprehensive anticancer treatments centered on surgery, postoperative recurrence and tumor metastasis still significantly affect both prognosis and quality of life of the patient. Hence, the development of precisely targeted tumor therapies and exploration of immunotherapy represent additional strategies for tumor treatment. Photodynamic therapy (PDT) is a relatively safe treatment modality that not only induces multiple modes of tumor cell death but also mediates the secondary immunological responses against tumor resistance and metastasis. Ferroptosis, an iron-dependent type of programmed cell death characterized by accumulation of reactive oxygen species and lipid peroxidation products to lethal levels, has emerged as an attractive target trigger for tumor therapies. Recent research has revealed a close association between PDT and ferroptosis, suggesting that combining ferroptosis inducers with PDT could strengthen their synergistic anti-tumor efficiency. Here in this review, we discuss the rationale for combining PDT with ferroptosis inducers and highlight the progress of single-molecule photosensitizers to induce ferroptosis, as well as the applications of photosensitizers combined with other therapeutic drugs for collaborative therapy. Furthermore, given the current research dilemma, we propose potential therapeutic strategies to advance the combined usage of PDT and ferroptosis inducers, providing the basis and guidelines for prospective clinical translation and research directionality with regard to PDT.

Participation of lipids in the tumor response to photodynamic therapy and its exploitation for therapeutic gain

Hydroperoxides of unsaturated membrane lipids (LOOHs) are the most abundant non-radical intermediates generated by photodynamic therapy (PDT) of soft tissues such as tumors and have far longer average lifetimes than singlet oxygen or oxygen radicals formed during initial photodynamic action. LOOH-initiated post-irradiation damage to remaining membrane lipids (chain peroxidation) or to membrane-associated proteins remains largely unrecognized. Such after-light processes could occur during clinical oncological PDT, but this is not well-perceived by practitioners of this therapy. In general, the pivotal influence of lipids in tumor responses to PDT needs to be better appreciated. Of related importance is the fact that most malignant tumors have dramatically different lipid metabolism compared with healthy tissues, and this too is often ignored. The response of tumors to PDT appears especially vulnerable to manipulations within the tumor lipid microenvironment. This can be exploited for therapeutic gain with PDT, as exemplified here by the combined treatment with the antitumor lipid edelfosine.

Preoperative prediction of occult lymph node metastasis in patients with non-small cell lung cancer: a simple and widely applicable model

OBJECTIVE

Lymph node metastasis (LNM) is one of the most common pathways of metastasis in non-small cell lung cancer (NSCLC). Preoperative assessment of occult lymph node metastasis (OLNM) in NSCLC patients is beneficial for selecting appropriate treatment plans and improving patient prognosis.

METHOD

A total of 370 NSCLC patients were included in the study. Univariate and multivariate logistic regression analysis were used to screen potential risk factors for OLNM in preoperative NSCLC patients. And establish a nomogram for OLNM in NSCLC patients before surgery. Receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA) were used to evaluate the established nomogram.

RESULT

Both univariate and multivariate logistic regression analyses suggested that multiple tumors, ERBB2 missense mutation, CA125 levels, CA153 levels, tumor site, tumor length, and serum ferritin are potential risk factors for OLNM in NSCLC patients. The constructed nomogram was evaluated, and the consistency index (C-index) and area under the ROC curve of the model were both 0.846. The calibration curve showed that the predicted values of the model had a high degree of fit with the actual observed values, and DCA suggested that the above indicators had good utility.

CONCLUSION

The personalized scoring prediction model constructed based on multiple tumors, ERBB2 miss mutation, CA125 levels, CA153 levels, tumor site, tumor length, and serum ferritin can screen NSCLC patients who may have OLNM.

In situ endoscopic photodynamic therapy combined with immature DC vaccination induces a robust T cell response against peritoneal carcinomatosis

BACKGROUND

Immunogenic cell death (ICD) and ferroptosis have recently emerged as key factors in the anticancer immune response. Among the treatments able to induce ICD and the associated release of danger signals is photodynamic therapy (PDT). Ferroptosis for its part results from lipid peroxidation and is induced by CD8+ T cells to kill nearby cancer cells on IFN-γ production. We aimed to combine the two concepts, that is, to evaluate whether the strong pro-oxidant effects of PDT may promote ferroptosis and antigen release and to develop a procedure for in situ PDT to prepare the soil for highly endocytotic immature dendritic cell (iDC) adoptive transfer. This approach was implemented for managing peritoneal carcinomatosis, a lesion often associated with poor outcomes.

METHODS

We used three-dimensional (3D) heterotypic spheroids made of cancer cells, exposed them to a white light-activated OR141 photosensitizer (PS), and subsequently complexified them by adding iDC and naive lymphocytes. We next used a model of mouse peritoneal carcinomatosis and administered PDT using laparoscopy to locally induce photoactivation using the endoscope light. The immune response following adoptive transfer of iDC was tracked both in vivo and ex vivo using isolated immune cells from in situ vaccinated mice.

RESULTS

Cancer cells undergoing PDT-induced cell death significantly increased ICD markers and the infiltration of iDCs in spheroids, relying on ferroptosis. These actions induced the sequential activation of CD8+ and CD4+ T cells as revealed by a significant spheroid 3D structure deterioration and, remarkably, were not recapitulated by conventional ferroptosis inducer RSL3. Using LED light from an endoscope for in situ photoactivation of PS enabled us to apply the vaccination modality in mice with peritoneal tumors. Consecutive intraperitoneal injection of iDCs resulted in delayed tumor growth, increased survival rates, and prevented tumor relapse on rechallenge. CD8+ T cell response was supported by depletion experiments, nodal detection of early activated T cells, and ex vivo T cell-induced cytotoxicity toward spheroids.

CONCLUSIONS

The combination of in situ PDT locally delivered by an endoscope light and iDC administration induces a durable memory immune response against peritoneal carcinomatosis thereby opening new perspectives for the treatment of a life-threatening condition.

ROS: A "booster" for chronic inflammation and tumor metastasis

Reactive oxygen species (ROS) are a group of highly active molecules produced by normal cellular metabolism and play a crucial role in the human body. In recent years, researchers have increasingly discovered that ROS plays a vital role in the progression of chronic inflammation and tumor metastasis. The inflammatory tumor microenvironment established by chronic inflammation can induce ROS production through inflammatory cells. ROS can then directly damage DNA or indirectly activate cellular signaling pathways to promote tumor metastasis and development, including breast cancer, lung cancer, liver cancer, colorectal cancer, and so on. This review aims to elucidate the relationship between ROS, chronic inflammation, and tumor metastasis, explaining how chronic inflammation can induce tumor metastasis and how ROS can contribute to the evolution of chronic inflammation toward tumor metastasis. Interestingly, ROS can have a "double-edged sword" effect, promoting tumor metastasis in some cases and inhibiting it in others. This article also highlights the potential applications of ROS in inhibiting tumor metastasis and enhancing the precision of tumor-targeted therapy. Combining ROS with nanomaterials strategies may be a promising approach to enhance the efficacy of tumor treatment.

Epilipidomics reveals lipid fatty acid and headgroup modification in gas plasma-oxidized biomembranes

Lipids, possessing unsaturated fatty acid chains and polar regions with nucleophilic heteroatoms, represent suitable oxidation targets for autologous and heterologous reactive species. Lipid peroxidation products (LPPs) are highly heterogeneous, including hydroperoxides, alkenals, chlorination, or glycation. Accordingly, delineation of lipid targets, species type, resulting products, and oxidation level remains challenging. To this end, liposomal biomimetic models incorporating a phosphatidylcholine, -ethanolamine, and a sphingomyelin were used to deconvolute effects on a single lipid scale to predict potential modification product outcomes. To introduce oxidative modifications, gas plasma technology, a powerful pro-oxidant tool to promote LPP formation by forming highly abundant reactive species in the gas and liquid phases, was employed to liposomes. The plasma parameters (gas type/combination) were modified to modulate the resulting species-profile and LPP formation by enriching specific reactive species types over others. HR-LC-MS (Münzel and et al., 2017) [2] was employed for LPP identification. Moreover, the heavy oxygen isotope 18O was used to trace O2-incorporation into LPPs, providing first information on the plasma-mediated lipid peroxidation mechanism. We found that combination of lipid class and gas composition predetermined the type of attack: admixture of O2 to the plasma and the presence of nitrogen atoms with free electrons in the molecule lead to chlorination of the amide bond and headgroup. Here, atomic oxygen driven formation of hypochlorite is the major reactive species. In contrast, POPC yields mainly to LPPs with oxidation of the oleic acid tail, especially truncations, epoxidation, and hydroperoxide formation. Here, singlet oxygen is assumingly the major driver. 18O labelling revealed that gas phase derived reactive species are dominantly incorporated into the LPPs, supporting previous findings on gas-liquid interface chemistry. In summary, we here provided the first insights into gas plasma-mediated lipid peroxidation, which, employed in more complex cell and tissue models, may support identifying mechanisms of actions in plasma medicine.

Overcoming the effects of fluid shear stress in ovarian cancer cell lines: Doxorubicin alone or photodynamic priming to target platinum resistance

Resistance to platinum-based chemotherapies remains a significant challenge in advanced-stage high-grade serous ovarian carcinoma, and patients with malignant ascites face the poorest outcomes. It is, therefore, important to understand the effects of ascites, including the associated fluid shear stress (FSS), on phenotypic changes and therapy response, specifically FSS-induced chemotherapy resistance and the underlying mechanisms in ovarian cancer. This study investigated the effects of FSS on response to cisplatin, a platinum-based chemotherapy, and doxorubicin, an anthracycline, both of which are commonly used to manage advanced-stage ovarian cancer. Consistent with prior research, OVCAR-3 and Caov-3 cells cultivated under FSS demonstrated significant resistance to cisplatin. Examination of the role of mitochondria revealed an increase in mitochondrial DNA copy number and intracellular ATP content in cultures grown under FSS, suggesting that changes in mitochondria number and metabolic activity may contribute to platinum resistance. Interestingly, no resistance to doxorubicin was observed under FSS, the first such observation of a lack of resistance under these conditions. Finally, this study demonstrated the potential of photodynamic priming using benzoporphyrin derivative, a clinically approved photosensitizer that localizes in part to mitochondria and endoplasmic reticula, to enhance the efficacy of cisplatin, but not doxorubicin, thereby overcoming FSS-induced platinum resistance.

Ferroptosis-associated genes and compounds in renal cell carcinoma

As the main type of renal cell carcinoma (RCC), clear cell RCC (ccRCC) is often associated with the deletion or mutation of the von Hippel Lindau (VHL) gene, enhancement of glucose and lipid metabolism, and heterogeneity of the tumor microenvironment. VHL alterations in RCC cells lead to the activation of hypoxia-inducible factors and their downstream target vascular endothelial growth factor, and to the reprogramming of multiple cell death pathways and metabolic weakness, including ferroptosis, which are associated with targeted therapy or immunotherapy. The changes in biological metabolites (e.g., iron and lipids) support ferroptosis as a potential therapeutic strategy for RCC, while iron metabolism and ferroptosis regulation have been examined as anti-RCC agents in numerous studies, and various ferroptosis-related molecules have been shown to be related to the metastasis and prognosis of ccRCC. For example, glutathione peroxidase 4 and glutaminase inhibitors can inhibit pyrimidine synthesis and increase reactive oxygen species levels in VHL-deficient RCC cells. In addition, the release of damage-associated molecular patterns by tumor cells undergoing ferroptosis also mediates antitumor immunity, and immune therapy can synergize with targeted therapy or radiotherapy through ferroptosis. However, Inducing ferroptosis not only suppresses cancer, but also promotes cancer development due to its potential negative effects on anti-cancer immunity. Therefore, ferroptosis and various tumor microenviroment-related molecules may co-occur during the development and treatment of RCC, and further understanding of the interactions, core targets, and related drugs of ferroptosis may provide new combination drug strategies for RCC treatment. Here we summarize the key genes and compounds on ferroptosis and RCC in order to envision future treatment strategies and to provide sufficient information for overcoming RCC resistance through ferroptosis.

Significance of Programmed Cell Death Pathways in Neurodegenerative Diseases

Programmed cell death (PCD) is a form of cell death distinct from accidental cell death (ACD) and is also referred to as regulated cell death (RCD). Typically, PCD signaling events are precisely regulated by various biomolecules in both spatial and temporal contexts to promote neuronal development, establish neural architecture, and shape the central nervous system (CNS), although the role of PCD extends beyond the CNS. Abnormalities in PCD signaling cascades contribute to the irreversible loss of neuronal cells and function, leading to the onset and progression of neurodegenerative diseases. In this review, we summarize the molecular processes and features of different modalities of PCD, including apoptosis, necroptosis, pyroptosis, ferroptosis, cuproptosis, and other novel forms of PCD, and their effects on the pathogenesis of neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), multiple sclerosis (MS), traumatic brain injury (TBI), and stroke. Additionally, we examine the key factors involved in these PCD signaling pathways and discuss the potential for their development as therapeutic targets and strategies. Therefore, therapeutic strategies targeting the inhibition or facilitation of PCD signaling pathways offer a promising approach for clinical applications in treating neurodegenerative diseases.

Synthesis and Photodynamic Activities of Pyridine- or Pyridinium-Substituted Aza-BODIPY Photosensitizers

In this work, various novel pyridinyl- and pyridinium-modified Aza-BODIPY PSs were designed and constructed based on monoiodo Aza-BODIPY PSs (BDP-4 and BDP-15) in an attempt to construct "structure-inherent organelles-targeted" PSs to endow potential organelle-targeting ability. Pyridinyl PSs displayed potent photodynamic efficacy, and monorigidified PSs were very effective. The monorigidified PS 20 with meta-pyridinyl moiety displayed the most potent photoactivity and negligible dark toxicity with a favorable dark/phototoxicity ratio (>4800). To our surprise, monorigidified PS with meta-pyridinyl moiety (e.g., 20) was lipid droplet-targeted. 20 showed good cellular uptake and intracellular ROS generation compared with BDP-15. The preliminary cell death process exploration indicated that 20 resulted in lipid peroxidation and induced cell death through an iron-independent ferroptosis-like cell death pathway. In vivo antitumor efficacy experiments manifested that 20 significantly inhibited tumor growth and outperformed BDP-15 and Ce6 even under a single low-dose light irradiation (30 J/cm2).

Targeting lipid peroxidation-associated ferroptosis suppresses lung carcinoma progression by regulating cell cycle arrest

Lung carcinoma is a frequently encountered cancerous growth that affects the respiratory tract and has a high occurrence rate globally. In light of the ongoing worldwide health emergency, the significance of efficient therapeutic agents and strategies is of utmost importance. A meticulous control of the cell cycle is crucial for comprehending the pathophysiology and molecular causes of lung cancer, as well as for the formulation of efficacious therapeutic medicines. The mechanism by which cells synchronize cell cycle with cell survival and death is still not fully understood. In this study, we demonstrate that the halting of the cell cycle has a strong inhibitory impact on ferroptosis, a specific type of controlled cell death triggered by excessive lipid peroxidation at the membranes of cells. Ferroptosis is halted through the mechanism of cell cycle arrest, which involves the deposition of intracellular lipids mediated by diacylglycerol acyltransferase (DGAT). Excessive amounts of polyunsaturated fatty acids (PUFAs) are stored as triacylglycerols (TAGs) within inactive cells. As a result, inhibiting DGAT causes a rearrangement of PUFAs from TAGs to phospholipids and makes arrested cells more susceptible to ferroptosis. We demonstrate that certain lung cancer cells that are resistant to antimitotic drugs and have a slow-cycling behavior exhibit an increase in lipid droplets. Furthermore, we find that the growth of tumors resistant to 5-fluorouracil, lorlatinib, and docetaxel can be effectively suppressed by a combination treatment involving the use of ferroptosis inducers and DGAT inhibitors, which induces ferroptosis. Collectively, these findings demonstrate the involvement of cell cycle arrest in conferring resistance to ferroptosis and propose a potential therapeutic approach for addressing the challenge of slow-cycling malignancies that exhibit resistance to ferroptosis.

Role of ferroptosis in the pathogenesis of heart disease

Ferroptosis is a new form of regulated necrosis characterized by iron-dependent lipid peroxidation, leading to irreparable lipid damage, membrane permeabilization, and necrotic cell death. Ferroptosis has recently been implicated in the pathogenesis of multiple forms of heart disease such as myocardial infarction, cardiac hypertrophy, heart failure, and various cardiomyopathies. Important progress has also been made regarding how ferroptosis is regulated in vitro and in vivo as well as its role in cardiac homeostasis and disease pathogenesis. In this review, we discuss molecular mechanisms that regulates ferroptosis in the heart, including pathways leading to iron overload and lipid peroxidation as well as the roles of key organelles in this process. We also discuss recent findings pertaining to the new pathogenic role of ferroptosis in various forms of heart disease as well as genetic and pharmacologic strategies targeting ferroptosis in the heart.

HINT2 may be One Clinical Significance Target for Patient with Diabetes Mellitus and Reduced ROS-Induced Oxidative Stress and Ferroptosis by MCU

The World Health Organization (WHO) predicted that patients with diabetes around the world will increase to 600 million by 2040, of which about 1/3 will develop diabetic nephropathy (DN). Therefore, the present study aimed to uncover therapeutic effect of HINT2 and determined its possible mechanisms. Patients with diabetes mellitus and normal volunteers were enrolled at our hospital. Male C57BL/6 mice were fed with a high fat diet and injected intraperitoneally with STZ for once (100 mg/kg body weight). Mouse podocytes (MPC5) cells were induced with 20 mmol/l D-glucose. Inhibition of HINT2 mRNA expression levels in patients with DN was observed, compared with normal group. The serum of HINT2 mRNA expression was negative in correlation with blood sugar, tubulo-interstitial damage, glomerular damage score or urine protein level in patients with DN. HINT2 expression in kidney tissue of mice with DN were downregulated. HINT2 presented reduced DN and inflammation and ROS-induced oxidative stress in model of DN. HINT2 promoted ferroptosis in model of DN by mitochondrial membrane potential. HINT2 suppressed MCU expression in model of DN. HINT2 protein combined with MCU protein increased MCU protein ubiquitination. HINT2 triggers mitochondrial Ca2+ influx to increase ROS production level by MCU. Taken together, these findings demonstrated that HINT2 reduced ROS-induced Oxidative stress and ferroptosis by MCU, suggesting that HINT2 may be a feasible strategy to treat DN.

Use of parvovirus B19-like particles in self-illuminated photodynamic therapy for solid tumors

Bioluminescence resonance energy transfer photodynamic therapy, which uses light generated by bioluminescent proteins to activate photosensitizers and produce reactive oxygen species without the need for external irradiation, has shown promising results in cancer models. However, the characterization of delivery systems that can incorporate the components of this therapy for preferential delivery to the tumor remains necessary. In this work, we have characterized parvovirus B19-like particles (B19V-VLPs) as a platform for a photosensitizer and a bioluminescent protein. By chemical and biorthogonal conjugation, we conjugated rose Bengal photosensitizer and firefly luciferase to B19V-VLPs and a protein for added specificity. The results showed that B19V-VLPs can withstand decoration with all three components without affecting its structure or stability. The conjugated luciferase showed activity and was able to activate rose Bengal to produce singlet oxygen without the need for external light. The photodynamic reaction generated by the functionalized VLPs-B19 can decrease the viability of tumor cells in vitro and affect tumor growth and metastasis in the 4 T1 model. Treatment with functionalized VLPs-B19 also increased the percentage of CD4 and CD8 cell populations in the spleen and in inguinal lymph nodes compared to vehicle-treated mice. Our results support B19V-VLPs as a delivery platform for bioluminescent photodynamic therapy components to solid tumors.

TYMS Knockdown Suppresses Cells Proliferation, Promotes Ferroptosis via Inhibits PI3K/Akt/mTOR Signaling Pathway Activation in Triple Negative Breast Cancer

Triple-negative breast cancer (TNBC) is characterized by a grim prognosis and numerous challenges. The objective of our study was to examine the role of thymidylate synthase (TYMS) in TNBC and its impact on ferroptosis. The expression of TYMS was analyzed in databases, along with its prognostic correlation. TYMS positive expression was identified through immunohistochemistry (IHC), while real-time quantitative PCR (qRTPCR) was employed to measure TYMS mRNA levels in various cell lines. Western blotting was utilized to assess protein expression. Cell proliferation, mobility, apoptosis, and reactive oxygen species (ROS) levels were evaluated using CCK8, wound scratch healing assay, transwell assay, and flow cytometry, respectively. Additionally, a tumor xenograft model was established in BALB/c nude mice for further investigation. Tumor volume and weight were measured, and histopathological analysis using hematoxylin and eosin (H&E) staining was conducted to assess tumor tissue changes. IHC staining was employed to detect the expression of Ki67 in tumor tissues. High expression of TYMS was observed in TNBC and was found to be correlated with poor prognosis in patients. Among various cell lines, TYMS expression was highest in BT549 cells. Knockdown of TYMS resulted in suppression of cell proliferation and mobility, as well as promotion of apoptosis. Furthermore, knockdown of TYMS led to increased accumulation of ROS and Fe2+ levels, along with upregulation of ACLS4 expression and downregulation of glutathione peroxidase 4 (GPX4) expression. In vivo studies showed that knockdown of TYMS inhibited tumor growth. Additionally, knockdown of TYMS was associated with inhibition of mTOR, p-PI3K, and p-Akt expression. Our research showed that the knockdown of TYMS suppressed the TNBC progression by inhibited cells proliferation via ferroptosis. Its underlying mechanism is related to the PI3K /Akt pathway. Our study provides a novel sight for the suppression effect of TYMS on TNBC.

Ferroptosis in health and disease

Ferroptosis is a pervasive non-apoptotic form of cell death highly relevant in various degenerative diseases and malignancies. The hallmark of ferroptosis is uncontrolled and overwhelming peroxidation of polyunsaturated fatty acids contained in membrane phospholipids, which eventually leads to rupture of the plasma membrane. Ferroptosis is unique in that it is essentially a spontaneous, uncatalyzed chemical process based on perturbed iron and redox homeostasis contributing to the cell death process, but that it is nonetheless modulated by many metabolic nodes that impinge on the cells' susceptibility to ferroptosis. Among the various nodes affecting ferroptosis sensitivity, several have emerged as promising candidates for pharmacological intervention, rendering ferroptosis-related proteins attractive targets for the treatment of numerous currently incurable diseases. Herein, the current members of a Germany-wide research consortium focusing on ferroptosis research, as well as key external experts in ferroptosis who have made seminal contributions to this rapidly growing and exciting field of research, have gathered to provide a comprehensive, state-of-the-art review on ferroptosis. Specific topics include: basic mechanisms, in vivo relevance, specialized methodologies, chemical and pharmacological tools, and the potential contribution of ferroptosis to disease etiopathology and progression. We hope that this article will not only provide established scientists and newcomers to the field with an overview of the multiple facets of ferroptosis, but also encourage additional efforts to characterize further molecular pathways modulating ferroptosis, with the ultimate goal to develop novel pharmacotherapies to tackle the various diseases associated with - or caused by - ferroptosis.

Cyanine dyes in the mitochondria-targeting photodynamic and photothermal therapy

Mitochondrial dysregulation plays a significant role in the carcinogenesis. On the other hand, its destabilization strongly represses the viability and metastatic potential of cancer cells. Photodynamic and photothermal therapies (PDT and PTT) target mitochondria effectively, providing innovative and non-invasive anticancer therapeutic modalities. Cyanine dyes, with strong mitochondrial selectivity, show significant potential in enhancing PDT and PTT. The potential and limitations of cyanine dyes for mitochondrial PDT and PTT are discussed, along with their applications in combination therapies, theranostic techniques, and optimal delivery systems. Additionally, novel approaches for sonodynamic therapy using photoactive cyanine dyes are presented, highlighting advances in cancer treatment.

Crosstalk among mitophagy, pyroptosis, ferroptosis, and necroptosis in central nervous system injuries

Central nervous system injuries have a high rate of resulting in disability and mortality; however, at present, effective treatments are lacking. Programmed cell death, which is a genetically determined form of active and ordered cell death with many types, has recently attracted increasing attention due to its functions in determining the fate of cell survival. A growing number of studies have suggested that programmed cell death is involved in central nervous system injuries and plays an important role in the progression of brain damage. In this review, we provide an overview of the role of programmed cell death in central nervous system injuries, including the pathways involved in mitophagy, pyroptosis, ferroptosis, and necroptosis, and the underlying mechanisms by which mitophagy regulates pyroptosis, ferroptosis, and necroptosis. We also discuss the new direction of therapeutic strategies targeting mitophagy for the treatment of central nervous system injuries, with the aim to determine the connection between programmed cell death and central nervous system injuries and to identify new therapies to modulate programmed cell death following central nervous system injury. In conclusion, based on these properties and effects, interventions targeting programmed cell death could be developed as potential therapeutic agents for central nervous system injury patients.

PDLIM3 knockdown promotes ferroptosis in endometriosis progression via inducing Gli1 degradation and blocking Hedgehog signaling pathway

AIMS

Current evidence suggests that there is no completely effective method for endometriosis (EMS) without trauma due to diverse adverse effects. Reliable evidence illustrates that inhibiting ferroptosis is a potential strategy for EMS. We sufficiently verified that the expression of endogenous protein PDZ and LIM domain 3 (PDLIM3) was significantly increased in EMS.

METHODS

PDLIM3 knockdown reduced primary ectopic endometrial stromal cells' (EESCs) viability and migration, and elevated ferroptosis signaling indicators including Fe2+, malondialdehyde (MDA), and reactive oxygen species (ROS) in EESCs.

RESULTS

Mechanistic studies revealed that inhibition of PDLIM3 accelerated glioma-associated oncogene-1 (Gli1) degradation and further deactivated Hedgehog signaling. Gli1 inhibitor, GANT61, abrogated the impact of PDLIM3 deletion on EESC growth, migration, and ferroptosis. In vivo experiments suggested that PDLIM3 reduction repressed the growth of endometrial lesions. Likewise, repression of PDLIM3 promoted ferroptosis and attenuated Hedgehog signaling in endometrial lesions.

CONCLUSIONS

Collectively, silencing of PDLIM3 facilitates ferroptosis in EMS by inducing Gli1 degradation and blocking Hedgehog signaling. It may provide an alternative strategy for developing therapeutic agents of EMS in the future.

The Emerging Role of Ferroptosis in EBV-Associated Cancer: Implications for Cancer Therapy

Ferroptosis is a novel and iron-dependent form of programmed cell death, which has been implicated in the pathogenesis of various human cancers. EBV is a well-recognized oncogenic virus that controls multiple signaling pathways within the host cell, including ferroptosis signaling. Recent studies show that inducing ferroptosis could be an efficient therapeutic strategy for EBV-associated tumors. This review will firstly describe the mechanism of ferroptosis, then summarize EBV infection and EBV-associated tumors, as well as the crosstalk between EBV infection and the ferroptosis signaling pathway, and finally discuss the role and potential application of ferroptosis-related reagents in EBV-associated tumors.

The multifaceted perspectives on the regulation of lncRNAs in hepatocellular carcinoma ferroptosis: from bench-to-bedside

Despite being characterized by high malignancy, high morbidity, and low survival rates, the underlying mechanism of hepatocellular carcinoma (HCC) has not been fully elucidated. Ferroptosis, a non-apoptotic form of regulated cell death, possesses distinct morphological, biochemical, and genetic characteristics compared to other types of cell death. Dysregulated actions within the molecular network that regulates ferroptosis have been identified as significant contributors to the progression of HCC. Long non-coding RNAs (lncRNAs) have emerged as influential contributors to diverse cellular processes, regulating gene function and expression through multiple mechanistic pathways. An increasing body of evidence indicates that deregulated lncRNAs are implicated in regulating malignant events such as cell proliferation, growth, invasion, and metabolism by influencing ferroptosis in HCC. Therefore, elucidating the inherent role of ferroptosis and the modulatory functions of lncRNAs on ferroptosis in HCC might promote the development of novel therapeutic interventions for this disease. This review provides a succinct overview of the roles of ferroptosis and ferroptosis-related lncRNAs in HCC progression and treatment, aiming to drive the development of promising therapeutic targets and biomarkers for HCC patients.

Mechanisms and therapeutic targets of ferroptosis: Implications for nanomedicine design

Ferroptosis is a nonapoptotic form of cell death and differs considerably from the well-known forms of cell death in terms of cell morphology, genetics, and biochemistry. The three primary pathways for cell ferroptosis are system Xc-/glutathione peroxidase 4 (GPX4), lipid metabolism, and ferric metabolism. Since the discovery of ferroptosis, mounting evidence has revealed its critical regulatory role in several diseases, especially as a novel potential target for cancer therapy, thereby attracting increasing attention in the fields of tumor biology and anti-tumor therapy. Accordingly, broad prospects exist for identifying ferroptosis as a potential therapeutic target. In this review, we aimed to systematically summarize the activation and defense mechanisms of ferroptosis, highlight the therapeutic targets, and discuss the design of nanomedicines for ferroptosis regulation. In addition, we opted to present the advantages and disadvantages of current ferroptosis research and provide an optimistic vision of future directions in related fields. Overall, we aim to provide new ideas for further ferroptosis research and inspire new strategies for disease diagnosis and treatment.

Photodynamic therapy for cancer: mechanisms, photosensitizers, nanocarriers, and clinical studies

Photodynamic therapy (PDT) is a temporally and spatially precisely controllable, noninvasive, and potentially highly efficient method of phototherapy. The three components of PDT primarily include photosensitizers, oxygen, and light. PDT employs specific wavelengths of light to active photosensitizers at the tumor site, generating reactive oxygen species that are fatal to tumor cells. Nevertheless, traditional photosensitizers have disadvantages such as poor water solubility, severe oxygen-dependency, and low targetability, and the light is difficult to penetrate the deep tumor tissue, which remains the toughest task in the application of PDT in the clinic. Here, we systematically summarize the development and the molecular mechanisms of photosensitizers, and the challenges of PDT in tumor management, highlighting the advantages of nanocarriers-based PDT against cancer. The development of third generation photosensitizers has opened up new horizons in PDT, and the cooperation between nanocarriers and PDT has attained satisfactory achievements. Finally, the clinical studies of PDT are discussed. Overall, we present an overview and our perspective of PDT in the field of tumor management, and we believe this work will provide a new insight into tumor-based PDT.

Identification of tumor antigens for mRNA vaccines and ferroptosis-related landscape in esophageal squamous cell carcinoma

Background

Ferroptosis, an iron-dependent form of cell death that is characterized by lipid peroxidation, has been implicated in conferring resistance to cancer therapies and may contribute to the pathogenesis of esophageal squamous cell carcinoma (ESCC). Furthermore, messenger RNA (mRNA) vaccines have emerged as a promising modality in the treatment arsenal against diverse malignancies. The aim of the study was to investigate the role of ferroptosis subtypes in ESCC and the immune microenvironment, as well as to identify key genes that could serve as targets for mRNA vaccine development.

Methods

Gene expression profiles and clinical data from 79 and 358 ESCC patients were collected from The Cancer Genome Atlas and Gene Expression Omnibus databases. Subsequently, we identified tumor mutational burden (TMB), immune microenvironment scores, and immune checkpoint and immune cell dysfunction genes for each ferroptosis subtype. Furthermore, we utilized weighted gene co-expression network analysis (WGCNA) to describe the immune landscape of ESCC and identify key genes for mRNA vaccine development.

Results

Our analysis revealed that MMD, MTDH, and TRFC were overexpressed ferroptosis genes in ESCC. In addition, ESCC was categorized into two ferroptosis subtypes, namely FS1 and FS2. Notably, FS2 exhibited a poorer prognosis, higher TMB, and increased immune cell infiltration when compared to FS1. The ferroptosis landscape analysis further revealed the presence of three distinct states. WGCNA analysis identified different modules of interest emerging as an independent prognostic factor and enriched with hub genes that could serve as targets for mRNA vaccine development.

Conclusions

The ferroptosis subtypes demonstrated significant associations with both prognosis and the immune microenvironment in ESCC. Additionally, the module of interest identified through immune landscape analysis represented an independent prognostic factor, with its contained genome offering promising targets for mRNA vaccine development.

Development and therapeutic implications of small molecular inhibitors that target calcium-related channels in tumor treatment

Calcium ion dysregulation exerts profound effects on various physiological activities such as tumor proliferation, migration, and drug resistance. Calcium-related channels play a regulatory role in maintaining calcium ion homeostasis, with most channels being highly expressed in tumor cells. Additionally, these channels serve as potential drug targets for the development of antitumor medications. In this review, we first discuss the current research status of these pathways, examining how they modulate various tumor functions such as epithelial-mesenchymal transition (EMT), metabolism, and drug resistance. Simultaneously, we summarize the recent progress in the study of novel small-molecule drugs over the past 5 years and their current status.

Mitigating phospholipid peroxidation of macrophages in stress-induced tumor microenvironment by natural ALOX15/PEBP1 complex inhibitors

BACKGROUND

The intricate interactions between chronic psychological stress and susceptibility to breast cancer have been recognized, yet the underlying mechanisms remain unexplored. Danzhi Xiaoyao Powder (DZXY), a traditional Chinese medicine (TCM) formula, has found clinical utility in the treatment of breast cancer. Macrophages, as the predominant immune cell population within the tumor microenvironment (TME), play a pivotal role in orchestrating tumor immunosurveillance. Emerging evidence suggests that lipid oxidation accumulation in TME macrophages, plays a critical role in breast cancer development and progression. However, a comprehensive understanding of the pharmacological mechanisms and active components of DZXY related to its clinical application in the treatment of stress-aggravated breast cancer remains elusive.

PURPOSE

This study sought to explore the plausible regulatory mechanisms and identify the key active components of DZXY contributing to its therapeutic efficacy in the context of breast cancer.

METHODS

Initially, we conducted an investigation into the relationship between the phagocytic capacity of macrophages damaged by psychological stress and phospholipid peroxidation using flow cytometry and LC-MS/MS-based phospholipomics. Subsequently, we evaluated the therapeutic efficacy of DZXY based on the results of the tumor size, tumor weight, the phospholipid peroxidation pathway and phagocytosis of macrophage. Additionally, the target-mediated characterization strategy based on binding of arachidonate 15-lipoxygenase (ALOX15) to phosphatidylethanolamine-binding protein-1 (PEBP1), including molecular docking analysis, microscale thermophoresis (MST) assay, co-immunoprecipitation analysis and activity verification, has been further implemented to reveal the key bio-active components in DZXY. Finally, we evaluated the therapeutic efficacy of isochlorogenic acid C (ICAC) based on the results of tumor size, tumor weight, the phospholipid peroxidation pathway, and macrophage phagocytosis in vivo.

RESULTS

The present study demonstrated that phospholipid peroxides, as determined by LC-MS/MS-based phospholipidomics, triggered in macrophages, which in turn compromised their capacity to eliminate tumor cells through phagocytosis. Furthermore, we elucidate the mechanism behind stress-induced PEBP1 to form a complex with ALOX15, thereby mediating membrane phospholipid peroxidation in macrophages. DZXY, demonstrates potent anti-breast cancer therapeutic effects by disrupting the ALOX15/PEBP1 interaction and inhibiting phospholipid peroxidation, ultimately enhancing macrophages' phagocytic capability towards tumor cells. Notably, ICAC emerged as a promising active component in DZXY, which can inhibit the ALOX15/PEBP1 interaction, thereby mitigating phospholipid peroxidation in macrophages.

CONCLUSION

Collectively, our findings elucidate stress increases the susceptibility of breast cancer by driving lipid peroxidation of macrophages and suggest the ALOX15/PEBP1 complex as a promising intervention target for DZXY.

A platinum(IV)-artesunate complex triggers ferroptosis by boosting cytoplasmic and mitochondrial lipid peroxidation to enhance tumor immunotherapy

Ferroptosis is an iron-dependent cell death form that initiates lipid peroxidation (LPO) in tumors. In recent years, there has been growing interest on ferroptosis, but how to propel it forward translational medicine remains in mist. Although experimental ferroptosis inducers such as RSL3 and erastin have demonstrated bioactivity in vitro, the poor antitumor outcome in animal model limits their development. In this study, we reveal a novel ferroptosis inducer, oxaliplatin-artesunate (OART), which exhibits substantial bioactivity in vitro and vivo, and we verify its feasibility in cancer immunotherapy. For mechanism, OART induces cytoplasmic and mitochondrial LPO to promote tumor ferroptosis, via inhibiting glutathione-mediated ferroptosis defense system, enhancing iron-dependent Fenton reaction, and initiating mitochondrial LPO. The destroyed mitochondrial membrane potential, disturbed mitochondrial fusion and fission, as well as downregulation of dihydroorotate dehydrogenase mutually contribute to mitochondrial LPO. Consequently, OART enhances tumor immunogenicity by releasing damage associated molecular patterns and promoting antigen presenting cells maturation, thereby transforming tumor environment from immunosuppressive to immunosensitive. By establishing in vivo model of tumorigenesis and lung metastasis, we verified that OART improves the systematic immune response. In summary, OART has enormous clinical potential for ferroptosis-based cancer therapy in translational medicine.

Long-chain acyl-CoA synthetase-4 regulates endometrial decidualization through a fatty acid β-oxidation pathway rather than lipid droplet accumulation

OBJECTIVE

Lipid metabolism plays an important role in early pregnancy, but its effects on decidualization are poorly understood. Fatty acids (FAs) must be esterified by fatty acyl-CoA synthetases to form biologically active acyl-CoA in order to enter the anabolic and/or catabolic pathway. Long-chain acyl-CoA synthetase 4 (ACSL4) is associated with female reproduction. However, whether it is involved in decidualization is unknown.

METHODS

The expression of ACSL4 in human and mouse endometrium was detected by immunohistochemistry. ACSL4 levels were regulated by the overexpression of ACSL4 plasmid or ACSL4 siRNA, and the effects of ACSL4 on decidualization markers and morphology of endometrial stromal cells (ESCs) were clarified. A pregnant mouse model was established to determine the effect of ACSL4 on the implantation efficiency of mouse embryos. Modulation of ACSL4 detects lipid anabolism and catabolism.

RESULTS

Through examining the expression level of ACSL4 in human endometrial tissues during proliferative and secretory phases, we found that ACSL4 was highly expressed during the secretory phase. Knockdown of ACSL4 suppressed decidualization and inhibited the mesenchymal-to-epithelial transition induced by MPA and db-cAMP in ESCs. Further, the knockdown of ACSL4 reduced the efficiency of embryo implantation in pregnant mice. Downregulation of ACSL4 inhibited FA β-oxidation and lipid droplet accumulation during decidualization. Interestingly, pharmacological and genetic inhibition of lipid droplet synthesis did not affect FA β-oxidation and decidualization, while the pharmacological and genetic inhibition of FA β-oxidation increased lipid droplet accumulation and inhibited decidualization. In addition, inhibition of β-oxidation was found to attenuate the promotion of decidualization by the upregulation of ACSL4. The decidualization damage caused by ACSL4 knockdown could be reversed by activating β-oxidation.

CONCLUSIONS

Our findings suggest that ACSL4 promotes endometrial decidualization by activating the β-oxidation pathway. This study provides interesting insights into our understanding of the mechanisms regulating lipid metabolism during decidualization.

Lanatoside C induces ferroptosis in non-small cell lung cancer in vivo and in vitro by regulating SLC7A11/GPX4 signaling pathway

Background

Non-small cell lung cancer (NSCLC) is a common malignant tumor worldwide, remaining resistant to chemotherapy drugs. Lanatoside C can inhibit the growth of cancer cell lines. In this study we aimed to investigate the relationship between lanatoside C and ferroptosis, exploring the possible mechanism in NSCLC.

Methods

Experiments in vitro and in vivo were conducted. A549 cells were used for in vitro, including cell counting kit-8 (CCK-8) assay, lactate dehydrogenase (LDH) release, western blotting, flow cytometry, transmission electron microscopy (TEM), and confocal microscopy. In vivo, a subcutaneous tumor model in nude mice using A549 cells was built and body size of the mice was observed. Ki67 immunohistochemistry, hematoxylin-eosin (HE) staining, and western blotting were conducted respectively.

Results

The results showed that lanatoside C had an inhibitory effect on the growth of A549 cells, and the dose of lanatoside C used in this experiment was set at 0.4 µM for 24 hours. When A549 cells were treated with lanatoside C, the cell viability was decreased observably (P<0.001) and LDH release was significantly enhanced (P<0.01) compared with the control group. However, when A549 cells were treated together with lanatoside C and five different inhibitors, containing ferroptosis inhibitors, necroptosis inhibitors, apoptosis inhibitors, pyroptosis inhibitors, and autophagy inhibitors, the results showed that the viability of A549 cells with lanatoside C and ferrostatin-1 (Fer-1) was reduced (P>0.05) and the LDH release was significantly enhanced (P<0.05). Besides, TEM and confocal microscopy showed that the mitochondria of A549 cells in the lanatoside C group disappeared and the mitochondrial membrane potential decreased. In vivo, lanatoside C efficiently enhanced the sensitivity of the xenograft tumors, as well as reducing the size and weight of the tumor. Moreover, immunohistochemical staining analysis revealed that the SLC7A11 and GPX4 levels significantly decreased in the lanatoside C group. In addition, the expression of GPX4 and SLC7A11 by western blotting was decreased in lanatoside C group.

Conclusions

Collectively, lanatoside C could inhibit the proliferation and induce ferroptosis, and have a biological effect on inducing ferroptosis in NSCLC.

Cr(VI) induces ferroptosis in DF-1 cells by simultaneously perturbing iron homeostasis of ferritinophagy and mitophagy

Hexavalent chromium [Cr(VI)] is an environmental pollutant known for its strong oxidizing and carcinogenic effects. However, its potential to induce ferroptosis in poultry remains poorly understood. This study aims to investigate the induction of ferroptosis by Cr(VI) in DF-1 cells and elucidate the underlying mechanisms. DF-1 cells exposed to Cr(VI) showed increased lipid reactive oxygen species and changes in ferroptosis marker genes (decreased expression of GPX4 and increased expression of COX2). Notably, the addition of the ferroptosis-specific inhibitor ferrostatin-1 (Fer-1) can reverse this effect. During the cell death process, Cr(VI) induced ferritinophagy, disrupting iron homeostasis and releasing labile iron ions. We predicted by docking that these iron ions would bind to mitochondrial membrane proteins through virtual docking. This binding was validated through colocalization analysis. In addition, Cr(VI) caused mitophagy, which releases additional ferrous ions. Therefore, Cr(VI) can induce the simultaneous release of ferrous ions through these pathways, thereby exacerbating lipid peroxidation and ultimately triggering ferroptosis in DF-1 cells. This study demonstrates that Cr(VI) can induce ferroptosis in DF-1 cells by disrupting intracellular iron homeostasis and providing valuable insights into the toxic effects of Cr(VI) in poultry and potentially other organisms.

A review on ferroptosis and photodynamic therapy synergism: Enhancing anticancer treatment

Ferroptosis is an iron-dependent programmed cell death modality, which has showed great potential in anticancer treatment. Photodynamic therapy (PDT) is widely used in clinic as an anticancer therapy. PDT combined with ferroptosis-promoting therapy has been found to be a promising strategy to improve anti-cancer therapy efficacy. Fenton reaction in ferroptosis can provide oxygen for PDT, and PDT can produce reactive oxygen species for Fenton reaction to enhance ferroptosis. In this review, we briefly present the importance of ferroptosis in anticancer treatment, mechanism of ferroptosis, researches on PDT induced ferroptosis, and the mechanism of the synergistic effect of PDT and ferroptosis on cancer killing.

Laser-Ignited Lipid Peroxidation Nanoamplifiers for Strengthening Tumor Photodynamic Therapy Through Aggravating Ferroptotic Propagation and Sustainable High Immunogenicity

Photodynamic therapy (PDT) is extensively investigated for tumor therapy in the clinic. However, the efficacy of PDT is severely limited by the tissue penetrability of light, short effective half-life and radius of reactive oxygen species (ROS), and the weak immunostimulatory effect. In this study, a glutathione (GSH)-activatable nano-photosensitizer is developed to load with arachidonic acid (AA) and camouflage by erythrocyte membrane, which serves as a laser-ignited lipid peroxidation nanoamplifier (MAR). The photosensitive effect of MAR is recovered accompanied by the degradation in the tumor microenvironment and triggers the peroxidation of AA upon laser excitation. Interestingly, it aggravates the propagation of ferroptosis among cancer cells by driving the continuous lipid peroxidation chain reactions with the participation of the degradation products, ferrous ions (Fe2+), and AA. Consequently, even the deep-seated tumor cells without illumination also undergo ferroptosis owing to the propagation of ferroptotic signal. Moreover, the residual tumor cells undergoing ferroptosis still maintain high immunogenicity after PDT, thus continuously triggering sufficient tumor-associated antigens (TAAs) release to remarkably promote the anti-tumor immune response. Therefore, this study will provide a novel "all-in-one" nano-photosensitizer that not only amplifies the damaging effect and expands the effective range of PDT but also improves the immunostimulatory effect after PDT.

Magnolin alleviated DSS-induced colitis by inhibiting ALOX5-mediated ferroptosis

Inflammatory bowel disease (IBD) is a chronic and incurable disorder associated with higher cancer risk and currently faces unsatisfactory treatment outcomes. Ferroptotic cells secrete damage-associated molecular patterns (DAMPs) that recruit and activate immune cells, particularly macrophages. Magnolin has excellent antioxidant and anti-inflammatory properties, but its effect on IBD has not yet been clearly understood. This study aimed to investigate the therapeutic effects and mechanism of magnolin in IBD. For this purpose, in vivo and in vitro colitis models were established using dextran sulfate sodium (DSS), followed by optimization of magnolin concentration 2.5 μg/mL in vitro and 5 mg/kg in vivo. Bioinformatics analysis identified potential magnolin target sites and evaluated ferroptosis-associated gene expressions. Body weight, food intake, disease activity index (DAI), pathological changes, and inflammation levels were assessed. The effect of magnolin on ferroptosis and macrophages was evaluated using quantitative real time-polymerase chain reaction (qRT-PCR), immunofluorescent staining, flow cytometry, enzyme-linked immunosorbent assay (ELISA), and western blotting. Results indicated that magnolin at a lower dose (5 mg/kg) alleviated DSS-induced colitis symptoms and reduced inflammation in mice. The bioinformatics analysis showed arachidonate 5-lipoxygenase (ALOX5) as a potential magnolin target. Furthermore, magnolin inhibited the expression of ALOX5 with no effect on GPX4. Moreover, magnolin regulated macrophage differentiation into the M2 phenotype and suppressed pro-inflammatory factors, that is, interleukin-6 and tumor necrosis factor-α (IL-6 and TNFα). These results suggested that magnolin possesses significant therapeutic potential in treating IBD by suppressing ALOX5-mediated ferroptosis, inhibiting M1 while promoting M2 macrophages, which is envisaged to provide novel strategies for treating IBD.

Advances in Ferroptosis-Inducing Agents by Targeted Delivery System in Cancer Therapy

Currently, cancer remains one of the most significant threats to human health. Treatment of most cancers remains challenging, despite the implementation of diverse therapies in clinical practice. In recent years, research on the mechanism of ferroptosis has presented novel perspectives for cancer treatment. Ferroptosis is a regulated cell death process caused by lipid peroxidation of membrane unsaturated fatty acids catalyzed by iron ions. The rapid development of bio-nanotechnology has generated considerable interest in exploiting iron-induced cell death as a new therapeutic target against cancer. This article provides a comprehensive overview of recent advancements at the intersection of iron-induced cell death and bionanotechnology. In this respect, the mechanism of iron-induced cell death and its relation to cancer are summarized. Furthermore, the feasibility of a nano-drug delivery system based on iron-induced cell death for cancer treatment is introduced and analyzed. Secondly, strategies for inducing iron-induced cell death using nanodrug delivery technology are discussed, including promoting Fenton reactions, inhibiting glutathione peroxidase 4, reducing low glutathione levels, and inhibiting system Xc-. Additionally, the article explores the potential of combined treatment strategies involving iron-induced cell death and bionanotechnology. Finally, the application prospects and challenges of iron-induced nanoagents for cancer treatment are discussed.

Lipid Peroxidation in Muscle Foods: Impact on Quality, Safety and Human Health

The issue of lipid changes in muscle foods under the action of atmospheric oxygen has captured the attention of researchers for over a century. Lipid oxidative processes initiate during the slaughtering of animals and persist throughout subsequent technological processing and storage of the finished product. The oxidation of lipids in muscle foods is a phenomenon extensively deliberated in the scientific community, acknowledged as one of the pivotal factors affecting their quality, safety, and human health. This review delves into the nature of lipid oxidation in muscle foods, highlighting mechanisms of free radical initiation and the propagation of oxidative processes. Special attention is given to the natural antioxidant protective system and dietary factors influencing the stability of muscle lipids. The review traces mechanisms inhibiting oxidative processes, exploring how changes in lipid oxidative substrates, prooxidant activity, and the antioxidant protective system play a role. A critical review of the oxidative stability and safety of meat products is provided. The impact of oxidative processes on the quality of muscle foods, including flavour, aroma, taste, colour, and texture, is scrutinised. Additionally, the review monitors the effect of oxidised muscle foods on human health, particularly in relation to the autooxidation of cholesterol. Associations with coronary cardiovascular disease, brain stroke, and carcinogenesis linked to oxidative stress, and various infections are discussed. Further studies are also needed to formulate appropriate technological solutions to reduce the risk of chemical hazards caused by the initiation and development of lipid peroxidation processes in muscle foods.

Induction of ferroptosis by photodynamic therapy and enhancement of antitumor effect with ferroptosis inducers

BACKGROUND

Photodynamic therapy (PDT) is an effective tumor treatment that involves the administration of a photosensitizer to generate cytotoxic 1O2 [reactive oxygen species (ROS)] from molecular oxygen that is produced from energy absorption following tumor irradiation at specific wavelengths. Ferroptosis is induced by the disruption of the glutathione peroxidase 4 (GPX4) antioxidant system, leading to lipid peroxidation. We hypothesized that talaporfin sodium-photodynamic therapy (TS-PDT)-generated ROS would lead to ferroptosis via accumulation of lipid peroxidation.

METHODS

Cell viability assay in TS-PDT-treated cells in combination with a ferroptosis inhibitor (ferrostatin-1: Fer-1) or ferroptosis inducers (imidazole ketone erastin: IKE, Ras-selective lethal 3: RSL3) was performed. Accumulation of lipid peroxidation, GPX4 antioxidant system and cystine/glutamate antiporter (system xc-) activity in TS-PDT-treated cells was investigated. In xenograft mice, the antitumor effect of TS-PDT in combination with ferroptosis inducers (IKE or sorafenib) was examined.

RESULTS

TS-PDT-induced cell death was partly suppressed by Fer-1 and accompanied by lipid peroxidation. TS-PDT combined with IKE or RSL3 enhanced the induction of cell death. TS-PDT inhibited cystine uptake activity via system xc-. In vivo, the combination of TS-PDT and ferroptosis inducers (IKE or sorafenib) reduced tumor volume.

CONCLUSION

This study found that the mechanism underlying TS-PDT-induced ferroptosis constitutes direct lipid peroxidation by the generated ROS, and the inhibition of system xc-, and that the combination of a ferroptosis inducer with TS-PDT enhances the antitumor effect of TS-PDT. Our findings suggest that ferroptosis-inducing therapies combined with PDT may benefit cancer patients.

Advances on the Role of Ferroptosis in Ionizing Radiation Response

Ferroptosis is an iron-dependent programmed cell death mode that is distinct from other cell death modes, and radiation is able to stimulate cellular oxidative stress and induce the production of large amounts of reactive oxygen radicals, which in turn leads to the accumulation of lipid peroxide and the onset of ferroptosis. In this review, from the perspective of the role of ferroptosis in generating a radiation response following cellular irradiation, the relationship between ferroptosis induced by ionizing radiation stress and the response to ionizing radiation is reviewed, including the roles of MAPK and Nrf2 signaling pathways in ferroptosis, resulting from the oxidative stress response to ionizing radiation, the metabolic regulatory role of the p53 gene in ferroptosis, and regulatory modes of action of iron metabolism and iron metabolism-related regulatory proteins in promoting and inhibiting ferroptosis. It provides some ideas for the follow-up research to explore the specific mechanism and regulatory network of ferroptosis in response to ionizing radiation.

Inhibition of ferroptosis by POLE2 in gastric cancer cells involves the activation of NRF2/GPX4 pathway

Gastric cancer results in great cancer mortality worldwide, and inducing ferroptosis dramatically improves the malignant phenotypes of gastric cancer. DNA polymerase epsilon subunit 2 (POLE2) plays indispensable roles in tumorigenesis; however, its involvement and molecular basis in ferroptosis and gastric cancer are not clear. Human gastric cancer cells were infected with lentiviral vectors to knock down or overexpress POLE2, and cell ferroptosis was detected. To further validate the involvement of nuclear factor erythroid 2-related factor 2 (NRF2) and glutathione peroxidase 4 (GPX4), lentiviral vectors were used. POLE2 expression was elevated in human gastric cancer cells and tissues and closely correlated with clinicopathological features in gastric cancer patients. POLE2 knockdown was induced, while POLE2 overexpression inhibited ferroptosis of human gastric cancer cells, thereby modulating the malignant phenotypes of gastric cancer. Mechanistic studies revealed that POLE2 overexpression elevated NRF2 expression and activity and subsequently activated GPX4, which then prevented lipid peroxidation and ferroptosis in human gastric cancer cells. In contrast, either NRF2 or GPX4 silence significantly prevented POLE2 overexpression-mediated inductions of cell proliferation, migration, invasion and inhibition of ferroptosis. POLE2 overexpression inhibits ferroptosis in human gastric cancer cells through activating NRF2/GPX4 pathway, and inhibiting POLE2 may be a crucial strategy to treat gastric cancer.

Photodynamic therapy in periodontitis: A narrative review

BACKGROUND

Periodontitis, a chronic infectious disease, is primarily caused by a dysbiotic microbiome, leading to the destruction of tooth-supporting tissues and tooth loss. Photodynamic therapy (PDT), which combines excitation light with photosensitizers (PS) and oxygen to produce antibacterial reactive oxygen species, is emerging as a promising adjuvant treatment for periodontitis.

METHODS

This review focuses on studies examining the antibacterial effects of PDT against periodontal pathogens. It also explores the impact of PDT on various aspects of periodontal health, including periodontal immune cells, human gingival fibroblasts, gingival collagen, inflammatory mediators, cytokines in the periodontium, vascular oxidative stress, vascular behavior, and alveolar bone health. Clinical trials assessing the types of PSs and light sources used in PDT, as well as its effects on clinical and immune factors in gingival sulcus fluid and the bacterial composition of dental plaque, are discussed.

RESULTS

The findings indicate that PDT is effective in reducing periodontal pathogens and improving markers of periodontal health. It has shown positive impacts on periodontal immune response, tissue integrity, and alveolar bone preservation. Clinical trials have demonstrated improvements in periodontal health and alterations in the microbial composition of dental plaque when PDT is used alongside conventional treatments.

CONCLUSIONS

PDT offers a promising adjunctive treatment for periodontitis, with benefits in bacterial reduction, tissue healing, and immune modulation. This article highlights the potential of PDT in periodontal therapy and emphasizes the need for further research to refine its clinical application and efficacy.

BASHY Dyes Are Highly Efficient Lipid Droplet-Targeting Photosensitizers that Induce Ferroptosis through Lipid Peroxidation

Ferroptosis is an iron-dependent lipid-peroxidation-driven mechanism of cell death and a promising therapeutic target to eradicate cancer cells. In this study, we discovered that boronic acid-derived salicylidenehydrazone (BASHY) dyes are highly efficient singlet-oxygen photosensitizers (PSs; ΦΔ up to 0.8) that induce ferroptosis triggered by photodynamic therapy. The best-performing BASHY dye displayed a high phototoxicity against the human glioblastoma multiform U87 cell line, with an IC50 value in the low nanomolar range (4.40 nM) and a remarkable phototoxicity index (PI > 22,700). Importantly, BASHY dyes were shown to accumulate in lipid droplets (LDs) and this intracellular partition was found to be essential for the enhanced phototoxicity and the induction of ferroptosis through lipid peroxidation. The safety and phototoxicity of this platform were validated using an in vivo zebrafish model (Danio rerio).

A Photoactive Supramolecular Complex Targeting PD-L1 Reveals a Weak Correlation between Photoactivation Efficiency and Receptor Expression Levels in Non-Small-Cell Lung Cancer Tumor Models

Photo-immunotherapy uses antibodies conjugated to photosensitizers to produce nanostructured constructs endowed with targeting properties and photo-inactivation capabilities towards tumor cells. The superficial receptor density on cancer cells is considered a determining factor for the efficacy of the photodynamic treatment. In this work, we propose the use of a photoactive conjugate that consists of the clinical grade PD-L1-binding monoclonal antibody Atezolizumab, covalently linked to either the well-known photosensitizer eosin or the fluorescent probe Alexa647. Using single-molecule localization microscopy (direct stochastic optical reconstruction microscopy, dSTORM), and an anti-PD-L1 monoclonal antibody labelled with Alexa647, we quantified the density of PD-L1 receptors exposed on the cell surface in two human non-small-cell lung cancer lines (H322 and A549) expressing PD-L1 to a different level. We then investigated if this value correlates with the effectiveness of the photodynamic treatment. The photodynamic treatment of H322 and A549 with the photo-immunoconjugate demonstrated its potential for PDT treatments, but the efficacy did not correlate with the PD-L1 expression levels. Our results provide additional evidence that receptor density does not determine a priori the level of photo-induced cell death.

Regulation of ferroptosis by lipid metabolism

Ferroptosis is an iron-dependent lethal mechanism that can be activated in disease and is a proposed target for cancer therapy. Ferroptosis is defined by the overwhelming accumulation of membrane lipid peroxides. Ferroptotic lipid peroxidation is initiated on internal membranes and then appears at the plasma membrane, triggering lethal ion imbalances and membrane permeabilization. Sensitivity to ferroptosis is governed by the levels of peroxidizable polyunsaturated lipids and associated lipid metabolic enzymes. A different network of enzymes and endogenous metabolites restrains lipid peroxidation by interfering with the initiation or propagation of this process. This emerging understanding is informing new approaches to treat disease by modulating lipid metabolism to enhance or inhibit ferroptosis.